I'd argue that 90% of innovation is someone saying "why don't we just do it this way?" and everyone else just replies "duh, why didn't we think of that."
@@TheRainHarvester the primary reason is cooling/fireproofing. Pouch cell packs have to be heavily armoured against both cell swelling and puncturing. cylindrical cells have a lot of that built in because of the shape
@rrobertt13 I heard manufacturing pouch cells is more difficult and costly than manufacturing cylindrical cells. Plus consider how the manufacturer will have to secure the prismatic type cells in a pack. They would need a heavy structural system to keep it stable and secured. This of course will take up space and add weight.
just calculate the optimal surface/volume size and you will see the "new" cell design comes close to that. eg: a can of coke. cell technology is just old fashion in new clothes. I would say: welcome back bigger brother of D-Cell
@@TheRainHarvester Aren't they. There were reports last year that they are using CATL's prismatic cells for the Asian produced cars. The 4680 are probably designed to reuse the whole equipment they already build for the cylindrical cells in the states. These bigger cells look like they are easier to cool than prismatics if they can direct contact them.
I understood the "jelly roll" but the tabless concept escapes me. Until you showed that toilet paper with those post-ts and then it dawned on me. Awesome! Good analog!
In the calculation of the internal resistance of a foil, the tabbed design was for a conductor 80 mm wide and 800 mm long, for the tab-less foil it was 80 mm long and 80 mm wide. (Website flashing by at 15:14) Shouldn't the width be 800 mm in the second case. This would make the internal resistance two magnitudes lower, not just one. Now, in real batteries the internal resistance is also affected by the resistance in the electrolyte and polarization of the electrode so it isn't as easy as just calculating the loss in the electrode material.
That is the problem for engineers - when you have a really great innovation it is hard to get any credit for it because it seems obvious after the fact
This is also not entirely without drawbacks. Copper is really expensive and you are going to have more of that with this design, and you have to figure out a reliable/fast/cheap way of cutting and folding the new tabs that are not tabs. Imagine the idea is you offset the cost of the copper with the simpler thermal system and other details. So this idea may have been thought of before but wasn't viable in other contexts, or that the tricky innovation was how to manufacture it well. devils in the details.
@@EEVblog I did tensile tests with the elasticated bits of diapers/nappies once, one of the big corps commissioned our university to do it. They sent us a pack and we spent an afternoon cutting the waists and leg cuffs out.
“Why hasn’t this been done before?” My guess: 1. Tradition (the “aye bin” approach if you’re Scottish). Batteries have always been made this way, so we won’t think about alternatives. 2. Existing companies don’t want to invest huge amounts in developing new methods to produce cells with cap ends. They’re already making a good deal of their old production line which has been going for a decade, they’re not about to pay someone to develop this, create machines to do it then halt production of their existing ones to retrofit in new ones. Tesla has the massive advantage of being a new-to-market (being battery market in this case) company and thus being able to look over their production top to bottom as they set up instead of retroactively. Plus Elon’s the kind of whacko who will throw money and time at this to make it perfect instead of settling for less. Just the sort of whacko we need right now.
Beautifully explained Dave. Its amazing how such a simple rethink of cell design to remove the tabs can resolve so many limitations of the previous cell generations. Very excited to see where these advantages, especially in manufacturing costs, bring the final cost of cells. I just may have to build my own powerwall some day!
Remember Dave, maximum packing density if circles/cylinders are always the same regardless of diameter. The tabless design allows for the removal of the cooling pipes between cells regardless of cell dimensions, so that density improvement isn't attributable to cell dimensions. It can however reduce the energy density with cell dimensions if there is less cell can and wiggle room needed for inserting the jelly roll.
That would be true if the ratio of jelly roll : hollow core : case were the same, but if the core is the same size and the case is the same thickness, you end up with a higher power density with larger cells when they are packed together.
@@ausnetting Exactly, I was going to make a comments that would be both of these. Lucky didn't take long to get to these. And you mean higher energy density not power. Yeah the energy density of the battery materials (anode, electrolyte, cathode, insulator) might be the same, but with there is probably 16% more energy holding material within the given total volume of the battery. Also there might be some minor increases in the % depletion and % charge that can be achieved based on the reduction of internal resistance, this would be so low that it would be negligible compared to the material ratio differences.
@@ausnetting My point is packing density of cylinders is always 90.69% solid with the rest wasted regardless of cylinder diameter (edit: or height) for Dave's 26:00 game "for those playing along at home". The cell itself may have a better energy density but the cell size itself will not lead to a better packing density of the cells into a pack in a apple to apples comparison. EDIT: yes on a technical level cell interconnects, cooling heatsink and edge of the cell packing density "may" improve but that needs information that us "playing along at home" don't have.
When you have cuts in a strip of material that is tensioned to be rolled up into a cylinder, you risk tearing it up and disrupting your high speed production line. They must have found a clever way to avoid this. Perhaps cutting the tabs as late as possible in the process.
Coud it be that you first glue a reinforcement/insulation strip onto the copper sheet. Or now that I think of it, could you cut them after you have rolled them?
It's possible they could have a rotating drum-cutter to cut the edge of the strip into tabs as the final step before the strip gets rolled up. Rolling and tab folding is definitely gonna be done in a single step. I agree though, that tab cutting is probably going to be as close to the last process step involving the strip as is practical.
This really shows how important it is to thoroughly examine assumptions. There is a story about a newlywed couple where one of them makes a roast and cuts off the ends before they start and the other asks why. This is the way my parents did it. When the parents are asked the reason was "the pan was too short". Doing things the same old way is a liability especially today when Every think is changing from week to week.
Please be reminded that 1) Conventional tab (have preload force) to secure contact resistance also spark proof. 2) Tab less / multi tab architecture have more tabs made of annealed soft copper to be in touch with casing (without a preload force) have undefined contact resistance. Tabs will deform under mechanical shock on road. It cannot reform itself once deformed. Gradually the effective (passing current) tab counts continues to drop as shock persists. When the last effective tab remains in the circuit the next shock will open circuit at that tab-case junction producing a spark next to hot chemical inside to a possible internal ignition/combustion.
Couldn't you solve that by just loading the cell itself? I.e. Squash it slightly between the two battery terminals. As a side benefit, you get better thermal conductivity at the end of the cells, which you want anyway.
@@dirkson I know what you mean and I agree with squash. Unfortunately squashing also requires a specific preload force to be stored in an elastomer associated with a conductor tap found in 18650 and 21700, is however removed along with the tap in the tab less 46800. There is a clean solution for all cylindrical type- one stone kills two problems. A solid metal wafer to conduct feat and current. Wafer created by magnetic induction heated soldering, jointing anode and cylinder base.
@@kinamod2k not exactly. AA cells work with an external spring is absent in 4680 cell. Electrical engineers don’t understand the distinctions between annealed vs hardened metal assuming the anode were annealed during jelly roll process, and falsely assume all anode flaps are hardened for spring, is the problem. Metals can’t behave in any state as an engineer expect it to be, annealed at one stage and magically hardened to the next. For all practical purposes these anode flaps begins annealed state and stay annealed during the jelly roll process. Annealed to avoid self delimitation - similar to the unwinding nature of a clock spring. So the anode flaps does not possess spring property, is more like annealed aluminum foil. At the end 4680 cell has no pre load (spring) force built in to enable good electrical contacts.
"i'd expect more than 16%" ... Watch battery day again. They state explicitly that the 5x power, 6x range, 16% range is due Only to the form factor. Then they walk through all the other advances and add in their effects, ending up with a 54% increase in range overall.
@@prich0382 Why would it jump that high? Lion batteries improve by about 6% a year. Tesla may have clever engineers but they still have to obey the laws of physics.
Yes, as per the pinned comment here, I missed this. I was bombarded with people and other news sources just mentioning this, I should have watched the whole thing for the context.
@@N0xiety How did you get that? A name cannot encompass the entirety of the function. But calling it "tabless" is incorrect, since it does have tabs...
The continuous tabs trick is pretty simple and obvious, I remember thinking about that years ago. My question is: why it wasn't done before? I mean, in comparison with the amount of knowledge and research in chemistry, this is nothing and improve noticably. Or just several tabs at least (was it already done in high C-rate cells?)
It probably has to do with the fact that this is the same than having a lot of small batteries in a pack maybe this makes them save on the container for all the batteries replaced by this single one but it's harder to manufacture
I had just the same question after watching this: are the battery designers kind of autistic and focus only on one part of the problem not knowing what the other department does with the package? I would not be surprised if that was the case XD
Cost. The competition has cheaper batteries. The increase in efficiency is minimal. Tesla has a habit of doing it anyway and then pretending it's bulletproof. Oh, snap. Anyway, without the overhype strategies of Tesla, practically no one would buy such batteries because practically no one lives in California or is a rich snob, meaning that most people will check cost vs. product and it's just not worth it to spend that much more for slightly better batteries.
26:28 isn't the packing efficiency for cilindres independent from its diameter? 16% is pretty impressive to be honest, its a high optimized product already
I think he is talking about the packing efficiency of the cell components. Since current is more evenly distributed, the ratio of conductor to electrode/electrolyte can be shifted to have less conductor (i.e. thinner conductors) The packing efficiency of "battery" to necessary wiring is improved.
It is, the upside is loosing a lot of metal from A: cell packs, B: idividual cell metal. Thats probably why its "only" 16% for now. Imo 16% is still huge, since they couldnt beat Tesla before, they certainly wont beat the new cells anytime soon.
Leonardo, you are correct (geometrically speaking) the packing density is about 92% regardless of diameter. When you start to account for the fewer can walls, you gain some. Also, the jelly rolls have a center gap, there are now fewer of these (another small gain), but not 16% worth, so the bulk of this must come from chemistry improvements.
My experience in Engineering has always been "if it ain't broke don't fix it" there are always new projects that require time. That is most likely why no one ever looked at the old battery designs. This was an excellent discussion. Thanks.
Many great inventions/solutions look obvious when found; it’s just a new way of looking at the problem that leads to the breakthrough. I love the elegance of these kind of solutions!
In large part, the original cell were designed for small cell counts, computers, in particular, also tools so the tabs acted as a Fuse to protect the user from failure
I still remember first press statements of a Californian company powering cars by notebook batteries. At that point in time the Tesla founders where still named Eberhard and Tarpenning. Later they siamized into Musk.
When I was a kid, learning about electricity, pre 1980, I made capacitors in various shapes with tin/aluminum foil, sticky tape, sandwich bags, plastic bottles, and paper clips. For the foil and tape versions, I rolled them up and folded over the edges, just like in the Tesla cells. I guess I should have patented it, but Leyden jars had already existed for 200 years.
I tried to predict before seeing it and got it wrong. I thought they were going to adopt the capacitor method of end connection as opposed to this folded tab design.
Good instructive video,Dave. It goes to show how newer generations of engineers sometimes suffer a sort of collective amnesia. The tabless roll design was invented decades ago with film capacitors for the same reasons.
Yeah with the larger cell you save about 16% weight in steel and replace that with cell. They didn't increase the energy density per cell just increased the thermal conductivity and electrical conductivity. Yes it is an order of magnitude, and that will result in less waste heat but still, the energy density of lithium is not changed with the cell design just efficiency.
That's awesome how they change the way engeineers and hobbyists see cylindrical batterys just adding these terminals along the conductive material. I hope these batteries out to the market outside tesla's cars and we can get this amount of energy and power in our scholar projects
It would be great if those batteries were on the market outside of tesla cars, but I think they might be too expensive to use for academic projects, it's just an opinion.
As you said, why didn't they come up with that before? Or it may seem really simple, but in reality it's not, only making physical changes, they could enhance the efficiency quite much
You don't get 16% more range by only using larger cells. It's the cooling solution needed for older cells that limits energy density. The newer 4680 cell does't need lateral cooling for cells, and that increase energy density. And the external metal case also decrease energy density. Big cells use les external metal cases in total, less weight ans space per battery.
Max packing density of identical circles is 0.9069, this is independent of diameter. The big savings of larger diameter is much less casing material and decrease in total plant number of operations, since you are processing fewer cells. And volumetric energy density isn't such a massive issue anyway (everybody drives an SUV), the real issue that matters for EVs is energy per unit mass. kWh/dm3 is def an issue, but not as high of a priority as kWh/kg. I think the reason they stick with cylindrical cell design is for increasing speed of production. Both prismatic and cylindrical cells are wound around a mandrel and winding speed per unit length is probably not hugely different, but with cylindrical cells you can use continuous motion assembly equipment to do all the further processes (like what you see in bottling plants with insane throughputs). This would definitely be a necessity if they plan to deliver their 2TWh/y or whatever musk's stated ambition is. Inb4 accused of being fan boy. I just think that if they're sticking with the cylinder design there is probably a very good reason. In the past that company has been very quick to kill their babies and abandon designs that didn't work, so I would expect them to do the same with the cylinder v prism design.
@EEVblog see this. Why bother then? I speculate that it has to do with overhead costs of packaging. 1 larger cell takes less material wrapping it up, takes less time to manufacture, etc. than multiples of lesser volume. Prismatic/pouch cells make the most sense until you consider all the supporting bits to securely position them safely inside of an automobile.
I don't know if it's the same design, but Tesla just bought Maxwell battery design in 2019. * So it's most likely they just made the Production process. What else they could do in a year?
I don't think this is a new technology except for in batteries possibly. Film capacitors have had non inductive variants for years now that mechanically do the same thing. I think in that case the ends are embedded in some conductive material rather than being folded over but the concept is the same.
true i had to figure out a way to do something that was not friendly/possible for what I was doing. then I ended up making an easier, more accurate & stronger way of doing it & it used less parts
This has been thought of before, but not successfully implemented in batteries, it may have appeared first successfully in Electrolytic Capacitors, particularly the axial electrolytic capacitors. This is why, I suspect this technique came from the engineering of Maxwell’s Supercapacitors!
Nice deep dive, Dave. The tabless construction allowing for both a decrease in ESR and in thermal resistance is huge. The only think that was missing was actual Amp-Hour numbers (or estimates of same)
aH should be more or less the same per linear length (chemical capacity), but instantaneous current (power) will be much higher (thermally/anode thickness limited) There's nothing stopping Tesla making the cells significantly larger than 46mm diameter. You're no longer constrained by the volume to surface area condundrum for cooling cells as your cooling requirement is now off the endfaces of the cells and as long as you're not making the cells st00pid-long the maximum thermal distance is the length of the cell
Great intro as always, Dave. I think the single tab leads on those plates initially did not make anybody concerned much as historically capacitors have been wound like that for decades. In fact, I have seen capacitors where the tabs were shaped from the plates directly, eliminating the need to weld contact terminals to the capacitor plates. This however became more of an issue with batteries where energy both in quantity and induration is far greater as opposed to capacitors, which also can get warm if their power handling is high.
Great vid, there is an entire recycling system as part of the battery technology development as well, so that makes the solution irresistible. Also, thermal paste between end cap and folded copper would be very efficient... unless chemical reaction, but im sure that could be resolved. Wonder how this transforms drone tech. And portable tools...
Dave is a huge BTTF nerd. You might have noticed his time circuit and OUTATIME license plate in his usual set. Also, the choice of model number for his self-branded multimeter, 121GW might ring a bell.
What a great teacher you are!!! Don't forget these new batteries will be sandwiched into a pack which will be like a hollow door which only have a cardboard honeycomb inside but are amazingly strong and rigid, hard to twist, so the batteries become a structural element of the car.
Maybe not new a Toyota Prius, but around 15 years ago when I was working at Toyota I watch a tech put dielectric grease on the connections in a recall of the battery bank and it was all 18650 cells on the inside. I remember it quite well because I sat and listened to the tech explain the entire battery and because I am a nerd it was right up my alley.
There is 2 separator layers so when you start to roll things the top of the copper doesn’t touch the bottom of the aluminum. You can see that in the picture at 14 minutes 45 seconds. It goes: separator , aluminum, separator, copper. With the electrolyte between everything. When people draw the roll flat they regularly miss the second layer of separator.
Manufacturing batteries using the induction-welded (IW) Tabs is very easy for the volume of production that was necessary for the world's consumption of laptops etc. The volumes required for EV's is much greater and so the requirement for "no-stop" manufacturing is essential. Musk explains this on battery day. Likely another reason why the IW-Tabs were used is due to re-use of existing manufacturing methods/facilities used for older designs. R&D is expensive and anywhere they can save a buck is exploited. For each method of manufacturing (anything) at a given rate, a dollar value can be applied to the investment required to reach that rate. This rate is not reached instantaneously upon completion of the factory, but accelerates, and when the ceiling for that method's rate is reached, further investment is required. This trend when graphed looks something like a serrated/saw-toothed line on a graph of investment vs production rate.
I figure the added cost of copper per cell would be a breakingpoint for tabless design at the time many battery designs were chosen (most likely disposables rather than longlife rechargeables). And as you said once the infrastructure is in place there is huge investment involved in retooling an optimised productionline.
Nope, 6months ago it was percieved to be worth it's worth in gold. You western noobs have no understanding of what recycling really is and where it starts.
AFAIK they didnt do it earlier as there was a higher change of accidental short when rolling. Maybe tesla has figured out a way to reduce that probability in production
I did not read all comments, so sorry if duplicated. Big Clive calls it "Schoopage" after the inventor of the folded contact design (which is apparently also used in capacitors).
If the 4680 cell replaces 5 of the 18650/2170 cells with 10 times less resistance, that will only reduce the power loss, charging/discharging, by 2x for the whole battery pack. example (10A*10A * 0.02 = 2W*5 = 10W, 50A*50A*0.002 = 5W)
As he pointed out, there are no tabs involved. They just extended the current collector and made cuts in it to fold it together. So no tabs needed, the connection is directly to the current collector
@@hoedjeexplains3661 I agree with @Dennis Shows, it looks like a lot of tabs, if you slit the edge multiple times you have made multiple tabs. Just a marketing bullshit.
@@jellybean2032 depends on how you define tabs in a battery cell. In my opinion tabs are the extra thing they solder on, and so with that view it is truly tabless. Dennis uses another definition. But if the only difference for true tabless is that they slit and folded the current collector instead of it spiraling around, than I think there will never be tabless battery cells because that is impossible to get decent connection to the battery cell housing
I'm here after listening to Clive Mitchell's thoughts on the topic (and hearing about these new cells from him as well), so I'm excited like an electron!
I'd say that most of the greatest modifications, guided only by the video, are done, and only a few details and adjustments, can be made, such as increasing the size or the vertical integration we just saw here. Unless they start using a supermaterial or so, other features won't change dramatically the efficiency of the battery. This is only from my very short point of view, since I know very little about this. Perhaps I'm terribly wrong and it's really likely to see remarkable improvements in the near future.
I think increasing the battery size does increase the capacity and efficiency, but at some point it would become the same as other batteries. That is why I totally agree with you that if they want to continue innovating, they must use other materials, new or familiar.
Course they have chemistry researches and it's pretty important in the energy capacity but talking about the low resistance they reach just by adding these wires along the copper or conductive material is incredible because it provides the battery the possibility to give more power without waste much in warm
I'm pretty sure that in the future new materials will appear and batteries will be powerful, but also they have to keep in mind the batteries' chemistry.
Love your direct approach, this is how it works and really just comes down to size increase. Heat dissipation is better, but again size. Thanks for sharing.
On the subject of "folding tabs" being used along the length of the anode material (instead of single tabs)... Do you think a similar improvement could be made to electrolytic capacitors to improve their efficiency and speed of charge/discharge? I believe that all electrolytic caps use the single tab at the ends approach.
Now imagine if they could construct electrolytics or batteries with the schooperage end connection of film capacitors. Far lower ESR. Greatly increased charge/discharge current. Much better performance than these new Tesla batteries. Probably impossible to make, though.
@@EEVblog It's a common mistake to say the electrons have to travel end to end of a material. There has to be spacing between electrons called the valens band and the hole vacancies get to travel light speed. That causes the resistance across the material but the tabless design making it travel across, instead of along sure does help. The electrons still travel a cm per minute. Good, eh?
No it's a decimal point . Apparently this notation comes from smaller cells like the CR2032 where the height is in tenths of millimeters and it just carried over to the bigger ones. And for the small cells you need the extra precision.
It's actually your best asset, standing in front of the whiteboard and teaching us all. Much of the other stuff can be quite repetitive in terms of the wordings used. (...aficionados playing along at home.....etc) This was a joy. Cheerioh
Would be nice to see how they handle the cathode - everyone talks about the anode, but I haven't seen anyone mention what they intend to do with the cathode.
I don't see why it couldn't be somewhat similar, with maybe a small outer section of cathode spared. But even if it's just the anode, it's a substantial improvement and the incremental improvement of doing both ends may end up being relatively minor, especially regarding heat extraction.
They only showed the copper end, but it's called tabless design, not 1 tab instead of 2. The other end of a "tabless" design would be folded the same, for the same reasons and same benefit. The electrons move through both sheets in the exact same numbers. He just did the calculations for one sheet, but mean electron path length reduction is same order of magnitude difference on both sides (ends), so same order of magnitude difference overall.
“Tab-less” was an idea the industry chose to for go, out of technically challenged to pass current out better than standard welded tabs before Tesla stumble on it. Tab-less is a misunderstood title - the correct should be “multi tab” formed in J shape with point contact conduction. Yes the J formed annealed copper can pass heat and current from coiled core ready to be transfer BUT stay where they were at the tabs and not to the cell casing because the process is weld-less tabs (Tesla’s tab less assembly). It is quite challenging to effectively conduct those heat and electricity with point contacts that is reducing over time for no known means for conduction resilience, to keep all J tabs in good coupled to conductive cell casing. Why? Annealed copper do not hold shape that spring steel do. Mechanical and thermal shock will deform its J shape from conduction of heat and electricity. Remedy? In theory design in mechanical resilience to the assembly such as a spring, pushing the roll and contacts against the base of cell casing. On the other hand resilience’s axial force, heat and vehicle shock can delaminates the roll stack is a reliability issue. When the last J tabs have gone through thermal and mechanical shock next there will be spark electric arc inside the cell, as the last tab eventually get shaken off the cell casing. Is another reliability and performance issue. Tab less was a good idea stop short to the finish line.
He does seam to be climaxing over Tesla Company (oh look, they stole the good name of Telsa too) getting a patient on copying someone else idea from years ago.. nothing new from the con-artist team..
If the internal resistance is is so much lower, then does that mean the batteries would run cooler under load ? resistance generates heat !. if so then the reverse should also be true, that is, you could charge them up faster using a more powerful charger because their would be less resistance to the flow of charge and again, less heat generated.
Yep. The new 130 kWh pack may charge slightly faster on V3 Superchargers from down to max as it keeps long the high peak. We might see still 100 kW speed at 80% SOC. So less time charging for an increase from 300 to 500 miles (500 to 800 kilometers). Cool 😎
Yes a much lower internal resistance will allow to dissipate quite less heat under the same loads , allowing an higher C rates than current batteries. This means faster charging and more there will be more regen allowed, the lower heat production will also mean a more compact and light battery thermal management (allowing for a greater battery pack energy density)
the simplest answer to why no one thought of it before is because it was a necessity and we tend to make way better designs when there is a high need or necessity for them.
Nice explanation, even a year later! One point, yes resistance per cell is down but so is the number of cells per pack so I'm surprised it's such a big win overall.
Thanks for finding the time to make that one Dave. As I suspected it was a little talked up for just a new cell size and a slight change in the architecture. If all the other things pan out and they hit the overall 50% range gain it will be great, but I'm pretty skeptical about their theoretical numbers vs what we will really get when the time comes. 14% is the only real confirmed number I have seen so far, so I'm going to use that for now until they demonstrate all these other things working. We are still waiting on a hyperloop and a real mass transit tunnel after all, so I'm not holding my breath on a $25k EV unless it's like the boring tunnel and what is delivered is hugely short of any traditional expectations. Half expecting it to have seats as an option TBH, if not have some sort of strings attached deal like the free Xbox consoles with a subscription fee that just puts the cost elsewhere like a fee to access the charging network.
It's not that Tesla is the first one to think of getting rid of the tab, by going for a tabless design, Tesla is eliminating the cells internal protection at the positive terminal. Since OEMs made these for a variety of applications they had to set this safety feature. When Tesla has complete control over the end application, they can get rid of this and inturn add an external fuse wire.
Can't the individual tabs act as a fuse to be burnt out when a dendrite shorts that strip ? That would make these less likely to go into thermal runaway.
@@era31415 The "tabs" are all one single roll and directly connected on both sides. If it shorts out, the battery is toast one way or another. The only reason why it's split on the ends is so they can smoothly fold it over flat. It's done purely for mechanical reasons, not electrical.
Right.. but from purely theoretical point of view, once you have this flat mega-multi-tab formed and squished by the top/bottom plate, you can still put a protection circuit over that and add another contact plate. Surely that: (a) steals a bit of height from the cell (b) adds more manufacturing steps (c) adds more metal/etc = weight (d) the protection circuit starts being the choke point when calculating power transfer or internal resistance. But certainly that is doable. We've got protection circuits in smaller cylinder-shaped batteries, so it's not like Tesla's design prevents that. The question is, with 10x lower resistance and X times better heat transfer, do these batteries need internal protection circuits at all?
At 6:42, you show a cross section of the "jelly roll" showing how it's assembled. Making the cell tabless by utilizing the full length of the rolled material as shown is ingenious! However, wouldn't it also be possible to take the opposite electrode, the aluminum positive electrode and give it the same treatment? Aluminum has a very high heat conduction potential and this would allow pulling heat from both the negative and positive ends of the cell. With proper external heat sinking, the only heat in the cell would be caught up in the "chemistry" layers themselves, but with copper on one side, and aluminum on the other, this heat would be "sucked" away from the chemistry, making for a much more thermally stable cell. Whoever thought this up, earned his(or her) Christmas bonus!
@05:20 Pouch vs Cylindrical : there is one important and often overlooked difference - longevity. Pouch cells are better in almost every aspect of performance but they have one major disadvantage - they have a far shorter lifetime. The most common failure mode of pouch cells is not aging but delamination, that is the layers start to lose contact with each other. Often this happens long before chemical aging starts to have an impact on the battery. This is where cylindrical cells excel as the cylindrical construction allows for easily keeping pressure on the layered electrodes preventing them from delaminating. You could of course enclose pouch cells in a thick steel casing that would keep the layers together no matter what but geometry dicatates that such an enclosure would be very heavy and bulky and would negate any performance advantage the pouch cell had since it now becomes very heavy for what it can do. The cylindrical cell has the optimal geometry for keeping the layers together under pressure with the minimum amount of structural material. I'm pretty sure longevity is the primary reason they went for cylindrical cells. The tabless design will maintain this advantage while at the same time getting very close to pouch cells with regards to energy and power density. Pouch cells should only really be expected to last five years or less and we are indeed used to that sort of lifetime with our smartphones, laptops and such where it doesn't matter because the device itself doesn't last that long due to obsolescence. The EV manufacturers using pouch cells of course know this but they probably don't care because it is just enough to last through the warranty period so you will have to pay for a new battery yourself when it starts to lose capacity not long after the warranty ends whereas with cyclindrical cells comined with a good BMS and cooling will last way longer than that. On another note, I was actually quite shocked to find out that the tabless design is something new. I have always incorrectly assumed that high power cells would be constructed in this manner, which has been the normal way to build capacitors for a long time, especially low ESR electrolytics. I'm still finding it hard to understand why one would use the tabbed design at all - it just doesn't seem to make sense to me.
Perfect video and very well executed, the only thing I may add here, for the reason that nobody came up with the idea to remove the tabs before.. I believe it's a perfect example of just how dangerous it is to say: "but we've always done it like that!!"
the 5x energy is only from formfactor. Chemistry changes are not included in this number. +16% range probably means + 16% energy density (energy/weight). But also - this is only from form factor change + tabless design.
@@EEVblog Yes. But it was also explicitly stated on the presentation. Only think I don't understend why 5x energy - when volume is 5.5 bigger. Maybe empty space in the middle needs to be larger due to tabless design?
only cell design that is correct. The anode in itself gives more range increase .. i believer extra 20 procent range .. in total the new battery will give 56 procent more range .. this is insane!!
W P, the energy density by mass was not given in the battery day presentation, nor was enough information to infer it. But what was given was the data to infer a 10% less volumetric energy density with a 10% increase in volumetric power density. Funny thing is, any battery cell manufacturer (Panasonic, CATL, LG Chem, Samsung SGI) can do a similar change without using some “tabless” design. We all know the 18650 cells have a wide range in choice of energy:power. You can choose a 2600 mah cell with 30 A continuous discharge or go to he opposite extreme and have 3500 mah with 11 A continuous discharge rating. Tesla could have just asked Panasonic of any company to make a 4680 cell using known technology, and gotten some improvements in Wh/kg just due to the 30-40% less metal needed for the cell case (this is based on needing 50% less area but slightly higher thickness). The 16% range improvement is more marketable wankology. As we know there are ONLY two aspects of a battery that can increase range of an EV, More kWh and/or less weight. By them saying the form factor alone gives 16% range is misleading because if they merely took apart a standard range model 3 battery, pulled out the 2170 cells, and added appropriate 1/5 as many 4680 cells, but uses all the same modules, thermal management etc, (after making slight adjustments for the taller but fewer cells), then there is no way these will increase range 16%. One thing that is related is the Chinese Standard Range model 3 (with the partially empty modules) changed to LiFePO4 cells, and added enough to make up for the lower energy density. So they got a better battery, cobalt free, more range, and lower price. I guess the 4680 is also supposed to be cobalt free, which is probably why the volumetric energy density is lower than the 2170. And with tabless design they were able to get 10% more power.
@@imho7250 The final battery pack including cooling weighs less than the current long-range version. They said somewhere over 100 kg reduction so you can add loads like 1 fat passenger to the car 😁
Tesla is one of the greatest technological companies that hace ever existed. It is a company that always wants to innovate anda this video is the perfect example, in this case Tesla innovated in the battery chemistry and algo in manufacturing by making a new battery that it's better than the others. In my opinion, in the coming years Tesla will continue to make changes in the world, not only talking about batteries but also in the automotive field, just to give an example.
I think Tesla still has a lot to offer because as you say, it is one of the largest technology companies that has ever existed, and to maintain its prestige and level it will have to continue innovating and developing as much as possible.
As you said, Tesla is on the top of the innovative companies, and it'll enhance not only their services and products but also the way they are manufacturing them. This batteries are destined to it's electric cars, and that means Tesla's always one step ahead when it comes to sustainable vehicles
The volumetric efficiency of packing cylinders is always 90.69%, regardless of dimensions. So not sure what you're referring to by "improved volumetric efficiency"??
The steel casing of the cell is wasted volume which (assuming they use the same thickness steel on the new cells) will occupy a volume proportional to the surface area of each cylinder. It's a similar story with the required plastic filling to bind all of the cells together. The individual new cells will occupy a larger volume obviously, but their surface area to volume ratio will decrease so the proportion of space wasted by casings/structure/filling material in the battery will decrease.
I was thinking the same while watching the video. Perhaps the efficiency comes from secondary issues of less packaging and fewer cores. In a one meter square array, there are 48 x 48 of the 2170 cells and 22 x 22 of the 4680 cells If each cell uses a 0.25mm thick shrink fit cover and a 0.25mm thick steel case, each cell has 1mm(4x0.25mm) of its diameter of non-energy storage. Basically a reduction of energy storage area of 26mm along both axis of the meter square, about 5%. If the minimum empty core diameters are similar for both cell sizes there will be 1,820 fewer cores in a meter square array. Anyone know a typical area of the empty core?
@@musiphonix You don't need to bind the cells together, in fact this makes it impossible to replace faulty cells. You don't need anything between the cells besides coolant and this can be pumped through the existing triangular spaces between the cells in the lengthwise direction instead of perpendicular to the length in a separate tube as in the existing design. The steel casing of the cell is beneficial as you can seal the cooling system with off the shelf o-rings.
@@77gravity The electrolyte is not liquid but a solid material. It is still in the works but Toyota was to reveal their electric car this past summer at the Olympics and it was to have a solid state battery . Solid state lithium ion batteries would make a thousand mile range possible with very short charge times. Do a search for solid state batteries....quite interesting. the battery technology is rapidly advancing and Tesla is in the cutting edge.
Yup my first thought to. There are a few advantages with larger sizes, but a bigger cylinder wastes more space that will not be used directly for more cooling with this design. Also I know this is really not the intent, but can't help to wonder how the replacement batteries will be for old size packs, like all pre 202? models, when the new batteries become taller.
Thank-you. I have watched a lot of videos about the tabless battery, many with stranger accents than yours, and in about one hour of watching I was able to make a reasonable guess about that a "tabless battery" is, but your first whiteboard diagram confirmed what I had suspected in less than 2 seconds.
![Stromae, Pomme - “Ma Meilleure Ennemie” (from Arcane Season 2) [Official Visualizer]](http://i.ytimg.com/vi/1F3OGIFnW1k/mqdefault.jpg)
dude, this was a great explanation. It was super detailed and yet done with a fantastically accessible approach. Thanks so much man.
I'd argue that 90% of innovation is someone saying "why don't we just do it this way?" and everyone else just replies "duh, why didn't we think of that."
Why don't they just use pack cells?
@@TheRainHarvester the primary reason is cooling/fireproofing. Pouch cell packs have to be heavily armoured against both cell swelling and puncturing. cylindrical cells have a lot of that built in because of the shape
@rrobertt13 I heard manufacturing pouch cells is more difficult and costly than manufacturing cylindrical cells. Plus consider how the manufacturer will have to secure the prismatic type cells in a pack. They would need a heavy structural system to keep it stable and secured. This of course will take up space and add weight.
just calculate the optimal surface/volume size and you will see the "new" cell design comes close to that. eg: a can of coke.
cell technology is just old fashion in new clothes. I would say: welcome back bigger brother of D-Cell
@@TheRainHarvester Aren't they. There were reports last year that they are using CATL's prismatic cells for the Asian produced cars. The 4680 are probably designed to reuse the whole equipment they already build for the cylindrical cells in the states. These bigger cells look like they are easier to cool than prismatics if they can direct contact them.
I understood the "jelly roll" but the tabless concept escapes me. Until you showed that toilet paper with those post-ts and then it dawned on me. Awesome! Good analog!
Some capacitors are made in a similar way
Yes but now I only wipe my ass with copper sheets.
Everything makes more sense with big roll and post its.
@@klam77 oooOooOOOOooooOooOOOOoo the paaatent.
Isnt that a multi tap design? Instead of tables?
In the calculation of the internal resistance of a foil, the tabbed design was for a conductor 80 mm wide and 800 mm long, for the tab-less foil it was 80 mm long and 80 mm wide. (Website flashing by at 15:14) Shouldn't the width be 800 mm in the second case. This would make the internal resistance two magnitudes lower, not just one.
Now, in real batteries the internal resistance is also affected by the resistance in the electrolyte and polarization of the electrode so it isn't as easy as just calculating the loss in the electrode material.
Good point
I’ve noticed obvious things are generally only obvious after the fact.
That is the problem for engineers - when you have a really great innovation it is hard to get any credit for it because it seems obvious after the fact
Yes - that's obvious!
I just spent a paragraph saying this. Nicely done Sergei.
This is also not entirely without drawbacks. Copper is really expensive and you are going to have more of that with this design, and you have to figure out a reliable/fast/cheap way of cutting and folding the new tabs that are not tabs. Imagine the idea is you offset the cost of the copper with the simpler thermal system and other details. So this idea may have been thought of before but wasn't viable in other contexts, or that the tricky innovation was how to manufacture it well. devils in the details.
The thing is that they were able to scale the cell size without compromising, charging speed, power, and heat rejection.
Pretty good in my book.
Longer and thicker is better... obviously 😂😂
That's what she said.
EEVblog LOL
Its not the size that matters, its the way you use it!
Fnar fnar
@@EEVblog You made my day aha
It's good that you are self-employed. Imagine your boss looking over your shoulder while affixing Post-It notes to TP. "Hey Dave, whatcha doin'?"
I'm makin' a super battery, boss! (cell, I know)
I've tested the vibration and shock response of feminine hygiene pads before. True story. Wasn't a bit awkward getting that money reimbursed.
EEVblog WE want to know, now that you've talked about it! Second channel, maybe?
@@EEVblog I did tensile tests with the elasticated bits of diapers/nappies once, one of the big corps commissioned our university to do it. They sent us a pack and we spent an afternoon cutting the waists and leg cuffs out.
@@EEVblog We get to see that video when?
“Why hasn’t this been done before?”
My guess:
1. Tradition (the “aye bin” approach if you’re Scottish). Batteries have always been made this way, so we won’t think about alternatives.
2. Existing companies don’t want to invest huge amounts in developing new methods to produce cells with cap ends. They’re already making a good deal of their old production line which has been going for a decade, they’re not about to pay someone to develop this, create machines to do it then halt production of their existing ones to retrofit in new ones.
Tesla has the massive advantage of being a new-to-market (being battery market in this case) company and thus being able to look over their production top to bottom as they set up instead of retroactively. Plus Elon’s the kind of whacko who will throw money and time at this to make it perfect instead of settling for less. Just the sort of whacko we need right now.
We definitely need more perfectionist whackos with that amount of money and the right attitude \o/
Tradition and also the batteries were following the construction steps of electrolytic capacitors. Log strips of metal with tabs at the ends.
Ruslan Fernandez well said!
&, it was probably Goodenough🤓
@@quetzalcoatl-pl I am a perfectionist whacko just find me some money I'm what you need promise.
This guy's vibe is so great he could be giving you your cancer diagnosis and you would laugh
Why would I laugh? I would be interested how he would explain how he calculated my life expectancy.
As long as he said he could “tear it apart!”
He talks so much and repeats himself endlessly. You may loose interest and not get the message at all. Volume is no indication of quality.
@@jofie2302 ª
@@jofie2302 probably just him adapting to the audience I'm sure he knows he's speaking to
"Marketing Wankology" should be a class
It would be very valuable, given that nowadays investment is more important than profit.
Dave also used the phrase, "differential pairs buggering off". Hmm, is there some pattern here?
It exists, it's called Marketing 101
100% fat free! (solid sugar/gelatin candy)
English year 11 and 12. Persuasive language?
46 x 80mm is the EXACT dimension of a dunny roll. Now I know who was hoarding all of that toilet paper at the start of the pandemic.
... prototyping battery packs need certain ressources ....
There are NO COINCIDENCES
Is that what Australians call toilet paper or is it the name for a roll of battery material? That was what I first though when I heard it 😂
@@bears7777777 I heard of bog roll...
@@EEVblog When even hardcore rationalists are saying this, there's something big going on.
Imagine if they all had batterisers installed.
@@Okurka. same to you
Thats how you build a nuclear plant at home.
@@Okurka. Ah, the ol' youtube batteroo
That's illegal!
I sense an acquisition in the works...
Someone said at the Factory "This isn`t a Capacitor, this is a Battery".
lol this is what I was thinking
Beautifully explained Dave. Its amazing how such a simple rethink of cell design to remove the tabs can resolve so many limitations of the previous cell generations. Very excited to see where these advantages, especially in manufacturing costs, bring the final cost of cells. I just may have to build my own powerwall some day!
Remember Dave, maximum packing density if circles/cylinders are always the same regardless of diameter. The tabless design allows for the removal of the cooling pipes between cells regardless of cell dimensions, so that density improvement isn't attributable to cell dimensions. It can however reduce the energy density with cell dimensions if there is less cell can and wiggle room needed for inserting the jelly roll.
That would be true if the ratio of jelly roll : hollow core : case were the same, but if the core is the same size and the case is the same thickness, you end up with a higher power density with larger cells when they are packed together.
@@ausnetting Exactly, I was going to make a comments that would be both of these. Lucky didn't take long to get to these. And you mean higher energy density not power. Yeah the energy density of the battery materials (anode, electrolyte, cathode, insulator) might be the same, but with there is probably 16% more energy holding material within the given total volume of the battery. Also there might be some minor increases in the % depletion and % charge that can be achieved based on the reduction of internal resistance, this would be so low that it would be negligible compared to the material ratio differences.
@@ausnetting My point is packing density of cylinders is always 90.69% solid with the rest wasted regardless of cylinder diameter (edit: or height) for Dave's 26:00 game "for those playing along at home". The cell itself may have a better energy density but the cell size itself will not lead to a better packing density of the cells into a pack in a apple to apples comparison.
EDIT: yes on a technical level cell interconnects, cooling heatsink and edge of the cell packing density "may" improve but that needs information that us "playing along at home" don't have.
love the way Dave just gets carried away and bombarded us with tons of information.
When you have cuts in a strip of material that is tensioned to be rolled up into a cylinder, you risk tearing it up and disrupting your high speed production line. They must have found a clever way to avoid this. Perhaps cutting the tabs as late as possible in the process.
Coud it be that you first glue a reinforcement/insulation strip onto the copper sheet.
Or now that I think of it, could you cut them after you have rolled them?
Maybe using a sinusoidal cutting die to create the tabs would keep that from happening?
It's possible they could have a rotating drum-cutter to cut the edge of the strip into tabs as the final step before the strip gets rolled up. Rolling and tab folding is definitely gonna be done in a single step. I agree though, that tab cutting is probably going to be as close to the last process step involving the strip as is practical.
perforate and tear at the end?
It could be cut as it's being rolled.
This really shows how important it is to thoroughly examine assumptions. There is a story about a newlywed couple where one of them makes a roast and cuts off the ends before they start and the other asks why. This is the way my parents did it. When the parents are asked the reason was "the pan was too short". Doing things the same old way is a liability especially today when Every think is changing from week to week.
Only if you don't know the reason for doing it the old way and just assume. I disagree with your statement that the old way is always a liability.
@@chocolate_squiggle you have a point, I was unclear, "Doing things the same old way 'without examination'" would have made my point better.
Please be reminded that
1) Conventional tab (have preload force) to secure contact resistance also spark proof.
2) Tab less / multi tab architecture have more tabs made of annealed soft copper to be in touch with casing (without a preload force) have undefined contact resistance. Tabs will deform under mechanical shock on road. It cannot reform itself once deformed. Gradually the effective (passing current) tab counts continues to drop as shock persists. When the last effective tab remains in the circuit the next shock will open circuit at that tab-case junction producing a spark next to hot chemical inside to a possible internal ignition/combustion.
Couldn't you solve that by just loading the cell itself? I.e. Squash it slightly between the two battery terminals. As a side benefit, you get better thermal conductivity at the end of the cells, which you want anyway.
@@dirkson I know what you mean and I agree with squash. Unfortunately squashing also requires a specific preload force to be stored in an elastomer associated with a conductor tap found in 18650 and 21700, is however removed along with the tap in the tab less 46800.
There is a clean solution for all cylindrical type- one stone kills two problems. A solid metal wafer to conduct feat and current. Wafer created by magnetic induction heated soldering, jointing anode and cylinder base.
Isn’t this solved in a similar way to AA cells that use springs? You just build some give into it.
@@kinamod2k not exactly. AA cells work with an external spring is absent in 4680 cell. Electrical engineers don’t understand the distinctions between annealed vs hardened metal assuming the anode were annealed during jelly roll process, and falsely assume all anode flaps are hardened for spring, is the problem. Metals can’t behave in any state as an engineer expect it to be, annealed at one stage and magically hardened to the next. For all practical purposes these anode flaps begins annealed state and stay annealed during the jelly roll process. Annealed to avoid self delimitation - similar to the unwinding nature of a clock spring. So the anode flaps does not possess spring property, is more like annealed aluminum foil. At the end 4680 cell has no pre load (spring) force built in to enable good electrical contacts.
"i'd expect more than 16%" ... Watch battery day again. They state explicitly that the 5x power, 6x range, 16% range is due Only to the form factor. Then they walk through all the other advances and add in their effects, ending up with a 54% increase in range overall.
Still sounds a lot lower then it should be
@@prich0382 What should it be?
@@RunesLegacy idk at least 2 to 2.5 times
@@prich0382 Why would it jump that high? Lion batteries improve by about 6% a year. Tesla may have clever engineers but they still have to obey the laws of physics.
Yes, as per the pinned comment here, I missed this. I was bombarded with people and other news sources just mentioning this, I should have watched the whole thing for the context.
Thank you Dave, you always teach us something.
The tabless design is a good example of something that seems obvious once you see it
It's like 0306 capacitors and current sense resistors....
Well it isn't tabless is it... More correct would be non welded tab battery or multiple tab battery...
Selfschooping battery ;-)
@@truezulu By that logic, the whole battery itself is a huge tab...
@@N0xiety How did you get that?
A name cannot encompass the entirety of the function. But calling it "tabless" is incorrect, since it does have tabs...
So would the cathode side be the same extended, cut, and folded sheet, just with aluminum?
The continuous tabs trick is pretty simple and obvious, I remember thinking about that years ago. My question is: why it wasn't done before? I mean, in comparison with the amount of knowledge and research in chemistry, this is nothing and improve noticably. Or just several tabs at least (was it already done in high C-rate cells?)
It probably has to do with the fact that this is the same than having a lot of small batteries in a pack maybe this makes them save on the container for all the batteries replaced by this single one but it's harder to manufacture
I had just the same question after watching this: are the battery designers kind of autistic and focus only on one part of the problem not knowing what the other department does with the package? I would not be surprised if that was the case XD
Electrolytic cap makers did it 2 decades ago.... You really do have to wonder (It knocks the series inductance out too)
@@miscbits6399 Also foil caps. The whole roll of each electrodes are soldered together to increase current handling and decrease ESL.
Cost. The competition has cheaper batteries. The increase in efficiency is minimal. Tesla has a habit of doing it anyway and then pretending it's bulletproof. Oh, snap.
Anyway, without the overhype strategies of Tesla, practically no one would buy such batteries because practically no one lives in California or is a rich snob, meaning that most people will check cost vs. product and it's just not worth it to spend that much more for slightly better batteries.
It's hard to overstate how much Dave makes the world a better place with his videos. Sincere thanks.
26:28 isn't the packing efficiency for cilindres independent from its diameter?
16% is pretty impressive to be honest, its a high optimized product already
I think he is talking about the packing efficiency of the cell components. Since current is more evenly distributed, the ratio of conductor to electrode/electrolyte can be shifted to have less conductor (i.e. thinner conductors) The packing efficiency of "battery" to necessary wiring is improved.
@@senorjp21 well, there are cell walls. Those are kind of in-the-way.
It is, the upside is loosing a lot of metal from A: cell packs, B: idividual cell metal. Thats probably why its "only" 16% for now. Imo 16% is still huge, since they couldnt beat Tesla before, they certainly wont beat the new cells anytime soon.
Leonardo, you are correct (geometrically speaking) the packing density is about 92% regardless of diameter. When you start to account for the fewer can walls, you gain some. Also, the jelly rolls have a center gap, there are now fewer of these (another small gain), but not 16% worth, so the bulk of this must come from chemistry improvements.
Why don't they just use a pack design instead of cylindrical?
I finaly understand tabless design, it was so confusing before, thanks for the explanation.
Long videos, but the only channel I can rely on to get consistently accurate and well-informed explanations about the latest in the tech world
My experience in Engineering has always been "if it ain't broke don't fix it" there are always new projects that require time. That is most likely why no one ever looked at the old battery designs. This was an excellent discussion. Thanks.
Many great inventions/solutions look obvious when found; it’s just a new way of looking at the problem that leads to the breakthrough. I love the elegance of these kind of solutions!
In large part, the original cell were designed for small cell counts, computers, in particular, also tools so the tabs acted as a Fuse to protect the user from failure
I still remember first press statements of a Californian company powering cars by notebook batteries. At that point in time the Tesla founders where still named Eberhard and Tarpenning. Later they siamized into Musk.
Bigclive did a video correctly predicting that this was probably the "innovation" behind Tesla announcement. Nice technique anyway
When I was a kid, learning about electricity, pre 1980, I made capacitors in various shapes with tin/aluminum foil, sticky tape, sandwich bags, plastic bottles, and paper clips. For the foil and tape versions, I rolled them up and folded over the edges, just like in the Tesla cells. I guess I should have patented it, but Leyden jars had already existed for 200 years.
I tried to predict before seeing it and got it wrong. I thought they were going to adopt the capacitor method of end connection as opposed to this folded tab design.
It never ceases to amaze me your knowledge im surprised the new Dave battery patent isn't already out there cheers
Good instructive video,Dave.
It goes to show how newer generations of engineers sometimes suffer a sort of collective amnesia. The tabless roll design was invented decades ago with film capacitors for the same reasons.
Yeah with the larger cell you save about 16% weight in steel and replace that with cell. They didn't increase the energy density per cell just increased the thermal conductivity and electrical conductivity. Yes it is an order of magnitude, and that will result in less waste heat but still, the energy density of lithium is not changed with the cell design just efficiency.
Battery Engineer: So we need more tabs to get better current flow... how many do we need?
Tesla: Yes!
All the tabs!
Wow, thank you Dave. Appreciate your contributions.
That's awesome how they change the way engeineers and hobbyists see cylindrical batterys just adding these terminals along the conductive material.
I hope these batteries out to the market outside tesla's cars and we can get this amount of energy and power in our scholar projects
Thinking about what you said, having that energy in our hands for scholar projects would be great.
It would be great if those batteries were on the market outside of tesla cars, but I think they might be too expensive to use for academic projects, it's just an opinion.
As you said, why didn't they come up with that before? Or it may seem really simple, but in reality it's not, only making physical changes, they could enhance the efficiency quite much
You don't get 16% more range by only using larger cells. It's the cooling solution needed for older cells that limits energy density. The newer 4680 cell does't need lateral cooling for cells, and that increase energy density. And the external metal case also decrease energy density. Big cells use les external metal cases in total, less weight ans space per battery.
Max packing density of identical circles is 0.9069, this is independent of diameter. The big savings of larger diameter is much less casing material and decrease in total plant number of operations, since you are processing fewer cells. And volumetric energy density isn't such a massive issue anyway (everybody drives an SUV), the real issue that matters for EVs is energy per unit mass. kWh/dm3 is def an issue, but not as high of a priority as kWh/kg.
I think the reason they stick with cylindrical cell design is for increasing speed of production. Both prismatic and cylindrical cells are wound around a mandrel and winding speed per unit length is probably not hugely different, but with cylindrical cells you can use continuous motion assembly equipment to do all the further processes (like what you see in bottling plants with insane throughputs). This would definitely be a necessity if they plan to deliver their 2TWh/y or whatever musk's stated ambition is.
Inb4 accused of being fan boy. I just think that if they're sticking with the cylinder design there is probably a very good reason. In the past that company has been very quick to kill their babies and abandon designs that didn't work, so I would expect them to do the same with the cylinder v prism design.
I haven’t understood from all the talks what they’re doing on the other end is it folded too?
@EEVblog see this. Why bother then? I speculate that it has to do with overhead costs of packaging. 1 larger cell takes less material wrapping it up, takes less time to manufacture, etc. than multiples of lesser volume. Prismatic/pouch cells make the most sense until you consider all the supporting bits to securely position them safely inside of an automobile.
@@billjohnson8794 I think so, yes.
yes . continuous motion assembly
Why nobody else thought of it: Its hard until someone figures out how, then it's easy.
I don't know if it's the same design, but Tesla just bought Maxwell battery design in 2019.
* So it's most likely they just made the Production process.
What else they could do in a year?
I don't think this is a new technology except for in batteries possibly. Film capacitors have had non inductive variants for years now that mechanically do the same thing. I think in that case the ends are embedded in some conductive material rather than being folded over but the concept is the same.
They've been building supercaps with this tabless design forever, not sure why someone didn't think to build li-po cell using the same technique
true i had to figure out a way to do something that was not friendly/possible for what I was doing. then I ended up making an easier, more accurate & stronger way of doing it & it used less parts
This has been thought of before, but not successfully implemented in batteries, it may have appeared first successfully in Electrolytic Capacitors, particularly the axial electrolytic capacitors. This is why, I suspect this technique came from the engineering of Maxwell’s Supercapacitors!
Nice deep dive, Dave. The tabless construction allowing for both a decrease in ESR and in thermal resistance is huge. The only think that was missing was actual Amp-Hour numbers (or estimates of same)
aH should be more or less the same per linear length (chemical capacity), but instantaneous current (power) will be much higher (thermally/anode thickness limited)
There's nothing stopping Tesla making the cells significantly larger than 46mm diameter. You're no longer constrained by the volume to surface area condundrum for cooling cells as your cooling requirement is now off the endfaces of the cells and as long as you're not making the cells st00pid-long the maximum thermal distance is the length of the cell
Point made on energy density...Not going to get 6x range unless you can pack in 6x the energy, so 6x the mass ( for the same chemistry).
The best video explaining 4680 battery.
Great intro as always, Dave.
I think the single tab leads on those plates initially did not make anybody concerned much as historically capacitors have been wound like that for decades. In fact, I have seen capacitors where the tabs were shaped from the plates directly, eliminating the need to weld contact terminals to the capacitor plates. This however became more of an issue with batteries where energy both in quantity and induration is far greater as opposed to capacitors, which also can get warm if their power handling is high.
Great vid, there is an entire recycling system as part of the battery technology development as well, so that makes the solution irresistible.
Also, thermal paste between end cap and folded copper would be very efficient... unless chemical reaction, but im sure that could be resolved. Wonder how this transforms drone tech. And portable tools...
lol 11:58 "Please excuse the crudity of this model. I didn't have time to build it to scale or paint it" back to the future line
Dave is a huge BTTF nerd. You might have noticed his time circuit and OUTATIME license plate in his usual set. Also, the choice of model number for his self-branded multimeter, 121GW might ring a bell.
@@Gameboygenius i went bike riding and discovered a DeLorean in someone's driveway, it has blocks behind the wheels so I guess its inoperable
Sandy already cut and painted examples. But cannot roll out and reuse it later 😜
@@thabg007 That is the saddest thing I've heard all day. :(
ruclips.net/video/MqcSLlXcXoU/видео.html
Others that use cylindrical cells: Lucid, Rivian, Toyota PHEV, and hundreds of e-bikes and scooters.
Is your point that those fields will be reliant on Tesla?
Edit: I got 4 minutes into the video
au no. The host said he didn’t think anyone else was using cylindrical cells in transportation. That’s why I commented.
@@JoelSapp That's why I edited
au ok. All good.
Lucid and Rivian are still basically vaporware, Toyota is interesting though
what a wonderful presentation! Thanks for taking the time to make something like this! Interested in Tesla's battery day technology!
great review on the new TESLA 4680 cell design - so far the best I've watched! thanks Dave!
What a great teacher you are!!! Don't forget these new batteries will be sandwiched into a pack which will be like a hollow door which only have a cardboard honeycomb inside but are amazingly strong and rigid, hard to twist, so the batteries become a structural element of the car.
"4 times the size. 16 times the detail!"
Hahaha funny I thought the same 2 min. before I wrote this. Best marketing ever xD
And it just works
Maybe not new a Toyota Prius, but around 15 years ago when I was working at Toyota I watch a tech put dielectric grease on the connections in a recall of the battery bank and it was all 18650 cells on the inside. I remember it quite well because I sat and listened to the tech explain the entire battery and because I am a nerd it was right up my alley.
There is 2 separator layers so when you start to roll things the top of the copper doesn’t touch the bottom of the aluminum. You can see that in the picture at 14 minutes 45 seconds. It goes: separator , aluminum, separator, copper. With the electrolyte between everything.
When people draw the roll flat they regularly miss the second layer of separator.
Capacitor manufacturers will be able to produce super-low ESR caps like this!
I was wondering if through-hole cans will be better than smd bricks now! I'll ask buildzoid about his thoughts on that.
Aren't they already? Big Clive made a video on that few days ago.
They already do.
The OP probably means electrolytic caps, not your normal low-ESR ones.
They would have to pay for the rights to produce them.
They said that the +16% was strictly due to the size of the cell. So that was expected.
That's mostly the height difference, the packing density between 21mm and 46mm cells doesn't change much.
When its circled with a box you know its important
Really helpful gave a lot of knowledge and cleared all my doubts about the most confusing battery tech
Manufacturing batteries using the induction-welded (IW) Tabs is very easy for the volume of production that was necessary for the world's consumption of laptops etc.
The volumes required for EV's is much greater and so the requirement for "no-stop" manufacturing is essential. Musk explains this on battery day.
Likely another reason why the IW-Tabs were used is due to re-use of existing manufacturing methods/facilities used for older designs. R&D is expensive and anywhere they can save a buck is exploited.
For each method of manufacturing (anything) at a given rate, a dollar value can be applied to the investment required to reach that rate.
This rate is not reached instantaneously upon completion of the factory, but accelerates, and when the ceiling for that method's rate is reached, further investment is required.
This trend when graphed looks something like a serrated/saw-toothed line on a graph of investment vs production rate.
I figure the added cost of copper per cell would be a breakingpoint for tabless design at the time many battery designs were chosen (most likely disposables rather than longlife rechargeables). And as you said once the infrastructure is in place there is huge investment involved in retooling an optimised productionline.
be careful with that precious toilet paper 6 months ago it was worth its weight in gold!
Good news is Tesla can easily retool it's battery factories to make toilet paper if the need comes.
@@redsquirrelftw when the need comes. this game ain't going away too soon
Nope, 6months ago it was percieved to be worth it's worth in gold. You western noobs have no understanding of what recycling really is and where it starts.
@DerOldHerr Tesla is putting the golden roll inside a small tin. So yes, both are right 😁
AFAIK they didnt do it earlier as there was a higher change of accidental short when rolling. Maybe tesla has figured out a way to reduce that probability in production
I did not read all comments, so sorry if duplicated. Big Clive calls it "Schoopage" after the inventor of the folded contact design (which is apparently also used in capacitors).
and no mention of the "E" word (electrolyte)
If the 4680 cell replaces 5 of the 18650/2170 cells with 10 times less resistance, that will only reduce the power loss, charging/discharging, by 2x for the whole battery pack. example (10A*10A * 0.02 = 2W*5 = 10W, 50A*50A*0.002 = 5W)
Why do they call it tabless? It looks more like a "tabfull" design to me.
As he pointed out, there are no tabs involved. They just extended the current collector and made cuts in it to fold it together. So no tabs needed, the connection is directly to the current collector
@@hoedjeexplains3661 I agree with @Dennis Shows, it looks like a lot of tabs, if you slit the edge multiple times you have made multiple tabs. Just a marketing bullshit.
@@jellybean2032 depends on how you define tabs in a battery cell. In my opinion tabs are the extra thing they solder on, and so with that view it is truly tabless. Dennis uses another definition. But if the only difference for true tabless is that they slit and folded the current collector instead of it spiraling around, than I think there will never be tabless battery cells because that is impossible to get decent connection to the battery cell housing
hehe maybe its like why a circle has no corners, when it kinda has an infinite amount! :D
@@PresidentBust A corner is a hard angle where two line segments meet. A circle is made from one line and so cannot have even one corner.
incredibly good explanation as always thank you Dave
I'm here after listening to Clive Mitchell's thoughts on the topic (and hearing about these new cells from him as well), so I'm excited like an electron!
Big Clive? I never knew that his last name was public info.
@@Gameboygenius yes, Big Clive.
And yes, most of us know him not by his last name, since it's not necessary for enjoying his videos. ;D
who else loves Dave with in front of a whiteboard.
That is the way to teach during pandemic. Tell Mr. Orange 👉
I'd say that most of the greatest modifications, guided only by the video, are done, and only a few details and adjustments, can be made, such as increasing the size or the vertical integration we just saw here. Unless they start using a supermaterial or so, other features won't change dramatically the efficiency of the battery. This is only from my very short point of view, since I know very little about this. Perhaps I'm terribly wrong and it's really likely to see remarkable improvements in the near future.
I think increasing the battery size does increase the capacity and efficiency, but at some point it would become the same as other batteries. That is why I totally agree with you that if they want to continue innovating, they must use other materials, new or familiar.
Course they have chemistry researches and it's pretty important in the energy capacity but talking about the low resistance they reach just by adding these wires along the copper or conductive material is incredible because it provides the battery the possibility to give more power without waste much in warm
I'm pretty sure that in the future new materials will appear and batteries will be powerful, but also they have to keep in mind the batteries' chemistry.
Love your direct approach, this is how it works and really just comes down to size increase.
Heat dissipation is better, but again size.
Thanks for sharing.
In short: They attempt to square the circle. ;-)
The area is squared: a=pi*r^2
On the subject of "folding tabs" being used along the length of the anode material (instead of single tabs)... Do you think a similar improvement could be made to electrolytic capacitors to improve their efficiency and speed of charge/discharge? I believe that all electrolytic caps use the single tab at the ends approach.
Now imagine if they could construct electrolytics or batteries with the schooperage end connection of film capacitors. Far lower ESR. Greatly increased charge/discharge current. Much better performance than these new Tesla batteries. Probably impossible to make, though.
Other types of caps use this technique already. Could probably be applied to cylindrical electrolytics too if you wanted to.
@@EEVblog It's a common mistake to say the electrons have to travel end to end of a material. There has to be spacing between electrons called the valens band and the hole vacancies get to travel light speed. That causes the resistance across the material but the tabless design making it travel across, instead of along sure does help. The electrons still travel a cm per minute. Good, eh?
I wonder if It would be enough to harvest the mother of all renewable power sources. Lightning strikes!
1:17 - I think that the ‘0’ in 18650 denotes a cylindrical cell rather than a decimal point.
No it's a decimal point . Apparently this notation comes from smaller cells like the CR2032 where the height is in tenths of millimeters and it just carried over to the bigger ones. And for the small cells you need the extra precision.
@@adi331 So only one of the two dimensions has a decimal point?
@@ForViewingOnly yes
The 0 means cylinder shape
It's actually your best asset, standing in front of the whiteboard and teaching us all. Much of the other stuff can be quite repetitive in terms of the wordings used. (...aficionados playing along at home.....etc)
This was a joy. Cheerioh
Would be nice to see how they handle the cathode - everyone talks about the anode, but I haven't seen anyone mention what they intend to do with the cathode.
I don't see why it couldn't be somewhat similar, with maybe a small outer section of cathode spared. But even if it's just the anode, it's a substantial improvement and the incremental improvement of doing both ends may end up being relatively minor, especially regarding heat extraction.
They only showed the copper end, but it's called tabless design, not 1 tab instead of 2. The other end of a "tabless" design would be folded the same, for the same reasons and same benefit. The electrons move through both sheets in the exact same numbers. He just did the calculations for one sheet, but mean electron path length reduction is same order of magnitude difference on both sides (ends), so same order of magnitude difference overall.
“Tab-less” was an idea the industry chose to for go, out of technically challenged to pass current out better than standard welded tabs before Tesla stumble on it. Tab-less is a misunderstood title - the correct should be “multi tab” formed in J shape with point contact conduction.
Yes the J formed annealed copper can pass heat and current from coiled core ready to be transfer BUT stay where they were at the tabs and not to the cell casing because the process is weld-less tabs (Tesla’s tab less assembly). It is quite challenging to effectively conduct those heat and electricity with point contacts that is reducing over time for no known means for conduction resilience, to keep all J tabs in good coupled to conductive cell casing.
Why?
Annealed copper do not hold shape that spring steel do. Mechanical and thermal shock will deform its J shape from conduction of heat and electricity. Remedy? In theory design in mechanical resilience to the assembly such as a spring, pushing the roll and contacts against the base of cell casing. On the other hand resilience’s axial force, heat and vehicle shock can delaminates the roll stack is a reliability issue.
When the last J tabs have gone through thermal and mechanical shock next there will be spark electric arc inside the cell, as the last tab eventually get shaken off the cell casing. Is another reliability and performance issue.
Tab less was a good idea stop short to the finish line.
He does seam to be climaxing over Tesla Company (oh look, they stole the good name of Telsa too) getting a patient on copying someone else idea from years ago.. nothing new from the con-artist team..
I have always been told the zero at the end of 18650 was to represent it was a cylinder.
Yep right 0 means cylinder shape
If the internal resistance is is so much lower, then does that mean the batteries would run cooler under load ? resistance generates heat !. if so then the reverse should also be true, that is, you could charge them up faster using a more powerful charger because their would be less resistance to the flow of charge and again, less heat generated.
Yep. The new 130 kWh pack may charge slightly faster on V3 Superchargers from down to max as it keeps long the high peak. We might see still 100 kW speed at 80% SOC. So less time charging for an increase from 300 to 500 miles (500 to 800 kilometers). Cool 😎
Yes a much lower internal resistance will allow to dissipate quite less heat under the same loads , allowing an higher C rates than current batteries. This means faster charging and more there will be more regen allowed, the lower heat production will also mean a more compact and light battery thermal management (allowing for a greater battery pack energy density)
the simplest answer to why no one thought of it before is because it was a necessity and we tend to make way better designs when there is a high need or necessity for them.
Nice explanation, even a year later! One point, yes resistance per cell is down but so is the number of cells per pack so I'm surprised it's such a big win overall.
Thanks for finding the time to make that one Dave. As I suspected it was a little talked up for just a new cell size and a slight change in the architecture. If all the other things pan out and they hit the overall 50% range gain it will be great, but I'm pretty skeptical about their theoretical numbers vs what we will really get when the time comes. 14% is the only real confirmed number I have seen so far, so I'm going to use that for now until they demonstrate all these other things working. We are still waiting on a hyperloop and a real mass transit tunnel after all, so I'm not holding my breath on a $25k EV unless it's like the boring tunnel and what is delivered is hugely short of any traditional expectations. Half expecting it to have seats as an option TBH, if not have some sort of strings attached deal like the free Xbox consoles with a subscription fee that just puts the cost elsewhere like a fee to access the charging network.
So happy I found you many years ago. Most valuable channel on RUclips for me coming up as an engineer.
It's not that Tesla is the first one to think of getting rid of the tab, by going for a tabless design, Tesla is eliminating the cells internal protection at the positive terminal. Since OEMs made these for a variety of applications they had to set this safety feature. When Tesla has complete control over the end application, they can get rid of this and inturn add an external fuse wire.
Can't the individual tabs act as a fuse to be burnt out when a dendrite shorts that strip ?
That would make these less likely to go into thermal runaway.
@@era31415 The "tabs" are all one single roll and directly connected on both sides. If it shorts out, the battery is toast one way or another. The only reason why it's split on the ends is so they can smoothly fold it over flat. It's done purely for mechanical reasons, not electrical.
Right.. but from purely theoretical point of view, once you have this flat mega-multi-tab formed and squished by the top/bottom plate, you can still put a protection circuit over that and add another contact plate. Surely that: (a) steals a bit of height from the cell (b) adds more manufacturing steps (c) adds more metal/etc = weight (d) the protection circuit starts being the choke point when calculating power transfer or internal resistance. But certainly that is doable. We've got protection circuits in smaller cylinder-shaped batteries, so it's not like Tesla's design prevents that. The question is, with 10x lower resistance and X times better heat transfer, do these batteries need internal protection circuits at all?
At 6:42, you show a cross section of the "jelly roll" showing how it's assembled. Making the cell tabless by utilizing the full length of the rolled material as shown is ingenious! However, wouldn't it also be possible to take the opposite electrode, the aluminum positive electrode and give it the same treatment? Aluminum has a very high heat conduction potential and this would allow pulling heat from both the negative and positive ends of the cell. With proper external heat sinking, the only heat in the cell would be caught up in the "chemistry" layers themselves, but with copper on one side, and aluminum on the other, this heat would be "sucked" away from the chemistry, making for a much more thermally stable cell. Whoever thought this up, earned his(or her) Christmas bonus!
Excellent explanation. Thanks, Dave! Like you said, it's a win all-around. Congrats to the Tesla engineers!
3:17 Was expecting the next line to be "Don't believe me? Just ask your mom."
Please excuse the crudity of the model, I didn't have time to build it to scale or paint it.... Was that a Dr Emmet Brown quote?! 😂
@05:20 Pouch vs Cylindrical : there is one important and often overlooked difference - longevity. Pouch cells are better in almost every aspect of performance but they have one major disadvantage - they have a far shorter lifetime.
The most common failure mode of pouch cells is not aging but delamination, that is the layers start to lose contact with each other. Often this happens long before chemical aging starts to have an impact on the battery.
This is where cylindrical cells excel as the cylindrical construction allows for easily keeping pressure on the layered electrodes preventing them from delaminating. You could of course enclose pouch cells in a thick steel casing that would keep the layers together no matter what but geometry dicatates that such an enclosure would be very heavy and bulky and would negate any performance advantage the pouch cell had since it now becomes very heavy for what it can do.
The cylindrical cell has the optimal geometry for keeping the layers together under pressure with the minimum amount of structural material. I'm pretty sure longevity is the primary reason they went for cylindrical cells. The tabless design will maintain this advantage while at the same time getting very close to pouch cells with regards to energy and power density.
Pouch cells should only really be expected to last five years or less and we are indeed used to that sort of lifetime with our smartphones, laptops and such where it doesn't matter because the device itself doesn't last that long due to obsolescence.
The EV manufacturers using pouch cells of course know this but they probably don't care because it is just enough to last through the warranty period so you will have to pay for a new battery yourself when it starts to lose capacity not long after the warranty ends whereas with cyclindrical cells comined with a good BMS and cooling will last way longer than that.
On another note, I was actually quite shocked to find out that the tabless design is something new. I have always incorrectly assumed that high power cells would be constructed in this manner, which has been the normal way to build capacitors for a long time, especially low ESR electrolytics. I'm still finding it hard to understand why one would use the tabbed design at all - it just doesn't seem to make sense to me.
Perfect video and very well executed, the only thing I may add here, for the reason that nobody came up with the idea to remove the tabs before.. I believe it's a perfect example of just how dangerous it is to say: "but we've always done it like that!!"
Understanding how the tabs are folded to increase surface area…Wow! Thank you for the deep dive.
the 5x energy is only from formfactor. Chemistry changes are not included in this number. +16% range probably means + 16% energy density (energy/weight). But also - this is only from form factor change + tabless design.
That's what my calcs showed must be the case.
@@EEVblog Yes. But it was also explicitly stated on the presentation. Only think I don't understend why 5x energy - when volume is 5.5 bigger. Maybe empty space in the middle needs to be larger due to tabless design?
only cell design that is correct. The anode in itself gives more range increase .. i believer extra 20 procent range .. in total the new battery will give 56 procent more range .. this is insane!!
W P, the energy density by mass was not given in the battery day presentation, nor was enough information to infer it. But what was given was the data to infer a 10% less volumetric energy density with a 10% increase in volumetric power density.
Funny thing is, any battery cell manufacturer (Panasonic, CATL, LG Chem, Samsung SGI) can do a similar change without using some “tabless” design. We all know the 18650 cells have a wide range in choice of energy:power.
You can choose a 2600 mah cell with 30 A continuous discharge or go to he opposite extreme and have 3500 mah with 11 A continuous discharge rating.
Tesla could have just asked Panasonic of any company to make a 4680 cell using known technology, and gotten some improvements in Wh/kg just due to the 30-40% less metal needed for the cell case (this is based on needing 50% less area but slightly higher thickness).
The 16% range improvement is more marketable wankology. As we know there are ONLY two aspects of a battery that can increase range of an EV, More kWh and/or less weight. By them saying the form factor alone gives 16% range is misleading because if they merely took apart a standard range model 3 battery, pulled out the 2170 cells, and added appropriate 1/5 as many 4680 cells, but uses all the same modules, thermal management etc, (after making slight adjustments for the taller but fewer cells), then there is no way these will increase range 16%.
One thing that is related is the Chinese Standard Range model 3 (with the partially empty modules) changed to LiFePO4 cells, and added enough to make up for the lower energy density. So they got a better battery, cobalt free, more range, and lower price.
I guess the 4680 is also supposed to be cobalt free, which is probably why the volumetric energy density is lower than the 2170. And with tabless design they were able to get 10% more power.
@@imho7250 The final battery pack including cooling weighs less than the current long-range version. They said somewhere over 100 kg reduction so you can add loads like 1 fat passenger to the car 😁
Tesla is one of the greatest technological companies that hace ever existed. It is a company that always wants to innovate anda this video is the perfect example, in this case Tesla innovated in the battery chemistry and algo in manufacturing by making a new battery that it's better than the others.
In my opinion, in the coming years Tesla will continue to make changes in the world, not only talking about batteries but also in the automotive field, just to give an example.
I think Tesla still has a lot to offer because as you say, it is one of the largest technology companies that has ever existed, and to maintain its prestige and level it will have to continue innovating and developing as much as possible.
You're totally right
Is incredible just to imagine what they are going to create and how is each camp of engineering changing due to they researches
As you said, Tesla is on the top of the innovative companies, and it'll enhance not only their services and products but also the way they are manufacturing them. This batteries are destined to it's electric cars, and that means Tesla's always one step ahead when it comes to sustainable vehicles
Poly put the kettle on😂 now I cannot remember what’s the real name of that material, thanks.
polysomething
Are you on about ptfe?
I was searching for a video about these new batteries that would explain why they are better and this is easy to understand! Thanks so much!
Great presentation.
Clarified how 'Tabless' was achieved, and its implications for thermal and power management.
Many thanks.
The volumetric efficiency of packing cylinders is always 90.69%, regardless of dimensions. So not sure what you're referring to by "improved volumetric efficiency"??
They will be doing away with much of the liquid cooling for the new batteries,
So less space is needed between the batteries in the car.
The steel casing of the cell is wasted volume which (assuming they use the same thickness steel on the new cells) will occupy a volume proportional to the surface area of each cylinder. It's a similar story with the required plastic filling to bind all of the cells together. The individual new cells will occupy a larger volume obviously, but their surface area to volume ratio will decrease so the proportion of space wasted by casings/structure/filling material in the battery will decrease.
I was thinking the same while watching the video.
Perhaps the efficiency comes from secondary issues of less packaging and fewer cores.
In a one meter square array, there are 48 x 48 of the 2170 cells and 22 x 22 of the 4680 cells
If each cell uses a 0.25mm thick shrink fit cover and a 0.25mm thick steel case, each cell has 1mm(4x0.25mm) of its diameter of non-energy storage. Basically a reduction of energy storage area of 26mm along both axis of the meter square, about 5%.
If the minimum empty core diameters are similar for both cell sizes there will be 1,820 fewer cores in a meter square array.
Anyone know a typical area of the empty core?
@@musiphonix You don't need to bind the cells together, in fact this makes it impossible to replace faulty cells. You don't need anything between the cells besides coolant and this can be pumped through the existing triangular spaces between the cells in the lengthwise direction instead of perpendicular to the length in a separate tube as in the existing design. The steel casing of the cell is beneficial as you can seal the cooling system with off the shelf o-rings.
@@musiphonix Exactly.
When Tesla comes out with a solid state battery it will be truly interesting.
What is a "solid state" battery? They already move nothing but electrons. How much more "solid" can they get?
@@77gravity The electrolyte is not liquid but a solid material. It is still in the works but Toyota was to reveal their electric car this past summer at the Olympics and it was to have a solid state battery . Solid state lithium ion batteries would make a thousand mile range possible with very short charge times. Do a search for solid state batteries....quite interesting. the battery technology is rapidly advancing and Tesla is in the cutting edge.
@@manofreedom in this case i think is called dry instead of solid
Nitpick: you don't get better packing density by increasing the size of a cylinder.
Yup my first thought to. There are a few advantages with larger sizes, but a bigger cylinder wastes more space that will not be used directly for more cooling with this design. Also I know this is really not the intent, but can't help to wonder how the replacement batteries will be for old size packs, like all pre 202? models, when the new batteries become taller.
If the density is described energy per weight as it should, it doesn't matter so much. If it's energy per volume, it might be cheating
I wonder if you get rid of the TMS between the cells if it's a wash volumetrically with the larger cells?
Question 23:33, Answer 1:13:50 ( tesla's video livestreams 23 sept)
Thank-you.
I have watched a lot of videos about the tabless battery, many with stranger accents than yours, and in about one hour of watching I was able to make a reasonable guess about that a "tabless battery" is, but your first whiteboard diagram confirmed what I had suspected in less than 2 seconds.