Great Video as always. I am a vote for the 138S. There are a few reasons. 1. Many power module suppliers are creating 750V rated SiC mosfet packages 2. electrical losses are I^2*R, so current is the biggest impact to losses, however at road load, the current level differences will me minimal. 3. if the V2 charging infrastructure can handle this intermediate voltage, there is even less reason to switch to 800V quickly. One other point, the 800V cars today all have an on-vehicle voltage booster that allows them to use 400V charging infrastructure to charge the 800V pack. That is more costly, but it does work in the rare instances it is needed.
plus there is the other way, unlike porsche doing voltage doubling on 400V chargers (which is really not great solution), like hyundai/kia are doing - using motor inverters to "change" voltage as needed, which means one less (unnecessary and pricy) component
You can get 1200V rated SiC modules from the same manufacturers. My guess is that all automaker will switch to 800V sooner or later because there is not really any reason not to.
@@EinzigfreierName agreed, those are needed for the 800V, i was just mentioning that 750V devices may be an easy/cheaper upgrade for the ~500V packs coming to market. The fact they are making 750V devices means there is demand
If you are able to charge at home, then 400/800 V makes little difference. However, for owner, who can't charge the cars at home, charge speed dose matter. It affects significantly how long you are going to spend in charge station and also the refresh rate for charging station. Given EV is stilling in the early phase that selling to house owner is good enough. Once the market is crowded with competitor and needs to adapt more consumer. Low charging time will be a BIG feature.
Charging: The limiting factor is the cell. It is the characteristics of the cells that determines the charging curve. The maximum chemical reaction rate and heat generated does not change no matter what configuration is used. Total heat generated by the cells is the same regardless of electrical configuration.
Many times type THHN insulated conductors rated at 600V is used in commercial applications at 480/277V and the 600V rated insulation gives a comfortable margin for safety.
Voltage: A battery pack can be electrically divided into two. Put in series for operation but parallel for charging so the charging infrastructure does not need to change as long as the high voltage design does not exceed twice the lower voltage design.
Discharge: This is where the advantages are. There is little advantage at the pack level. On the external circuits the conductors can loose less power and be smaller but the spacing on circuit boards between two high voltage traces will need to be larger to prevent arcing between traces and creep through the circuit board material between. Since there are no uninsulated conductors there isn’t a related distance concern for open air arcing. For insulated conductors the insulation needs to have a higher rating so may get thicker and a space trade off analysis may need to be done if any tight space exists along the run path.
I dont think Tesla puts strings in parallel. (Someone correct me if otherwise). They put all cells into modules of parallel cells and then place the modules into series configuration only. So it would be correct that if there are less cells in parallel that if one fails, its a bigger proportion. But it wouldnt take out an "entire string", just that one cell. Also, there is less current due to the higher voltage so the impact of a bad cell is reduced further.
Going to higher voltage may save some material in the conductor size thats it. So the gauge of wire used in motors or wiring will be thinner but going to a thinner conductor alone does not save much money on the other hand working with higher voltage requires all the semiconductor and software and charging station to be upgraded. Makes no sense.
Bad Engineering Physics errors come from missing what is important: moving to higher voltages is really all about performance driving; significant charging advantages only come about as a bonus. Consider this: AC wiring needs to be safe not only up to rated supply voltages but also for switching power on and off, and especially for motors and other inductive loads where voltage surges need to go many multiples higher. For DC applications, we also expect to see nuisance over-voltages, in switching and beyond, wherever motors are ramping up and down under variable loads; but our primary concerns go further, to where desirable over-voltages come from regenerative braking, and where respective voltages routinely become extreme: keep in mind, most energy advantage in regenerative braking is always near and often beyond current BEV limits. Doubling operating voltage quite certainly gives real advantages in BEV design for performance: marketing regressive low voltage legacy technologies may work with non-technical business executives in the board room; not so much however in the real world of engineers and scientists.
Higher voltage requires lesser amperage in operation. It is better but the time it would take to optimize it would make Tesla lag the other car maker if they switched to a higher voltage.
400V is when human tissue ionizes and resistance drops. Current goes up substantially. So 400V is a good medium here. Although ideally there should sufficient safe guards like HVIL and Isolation detection so the occupants are never exposed to high voltage.
Great Video as always. I am a vote for the 138S. There are a few reasons. 1. Many power module suppliers are creating 750V rated SiC mosfet packages 2. electrical losses are I^2*R, so current is the biggest impact to losses, however at road load, the current level differences will me minimal. 3. if the V2 charging infrastructure can handle this intermediate voltage, there is even less reason to switch to 800V quickly. One other point, the 800V cars today all have an on-vehicle voltage booster that allows them to use 400V charging infrastructure to charge the 800V pack. That is more costly, but it does work in the rare instances it is needed.
plus there is the other way, unlike porsche doing voltage doubling on 400V chargers (which is really not great solution), like hyundai/kia are doing - using motor inverters to "change" voltage as needed, which means one less (unnecessary and pricy) component
You can get 1200V rated SiC modules from the same manufacturers. My guess is that all automaker will switch to 800V sooner or later because there is not really any reason not to.
@@EinzigfreierName agreed, those are needed for the 800V, i was just mentioning that 750V devices may be an easy/cheaper upgrade for the ~500V packs coming to market. The fact they are making 750V devices means there is demand
If you are able to charge at home, then 400/800 V makes little difference. However, for owner, who can't charge the cars at home, charge speed dose matter. It affects significantly how long you are going to spend in charge station and also the refresh rate for charging station. Given EV is stilling in the early phase that selling to house owner is good enough. Once the market is crowded with competitor and needs to adapt more consumer. Low charging time will be a BIG feature.
Charging: The limiting factor is the cell. It is the characteristics of the cells that determines the charging curve. The maximum chemical reaction rate and heat generated does not change no matter what configuration is used. Total heat generated by the cells is the same regardless of electrical configuration.
Why can Lucid do 300kW then? Better cooling? Because Lucid uses cylindrical NMC LG cells no different than Tesla MiC models.
@@boostav Probably because of very large 130ish KW packs
@@aljones8519 They're not 130kWh packs.
Many times type THHN insulated conductors rated at 600V is used in commercial applications at 480/277V and the 600V rated insulation gives a comfortable margin for safety.
Thank you for taking the time to dive deep into these topics. Very helpful.
Voltage: A battery pack can be electrically divided into two. Put in series for operation but parallel for charging so the charging infrastructure does not need to change as long as the high voltage design does not exceed twice the lower voltage design.
This requires at least an additional pack contactor (if not more) which is already $200.
Discharge: This is where the advantages are. There is little advantage at the pack level. On the external circuits the conductors can loose less power and be smaller but the spacing on circuit boards between two high voltage traces will need to be larger to prevent arcing between traces and creep through the circuit board material between. Since there are no uninsulated conductors there isn’t a related distance concern for open air arcing. For insulated conductors the insulation needs to have a higher rating so may get thicker and a space trade off analysis may need to be done if any tight space exists along the run path.
cybertruck 's 800v
Great video. Thanks
your videos are so good, why did you stop making them?
I dont think Tesla puts strings in parallel. (Someone correct me if otherwise). They put all cells into modules of parallel cells and then place the modules into series configuration only.
So it would be correct that if there are less cells in parallel that if one fails, its a bigger proportion. But it wouldnt take out an "entire string", just that one cell. Also, there is less current due to the higher voltage so the impact of a bad cell is reduced further.
Excellent Great technical video
If a cell fails by being electrically open, ok, but a cell can fail by being shorted or closed too, right? I wonder which is more common?
Going to higher voltage may save some material in the conductor size thats it. So the gauge of wire used in motors or wiring will be thinner but going to a thinner conductor alone does not save much money on the other hand working with higher voltage requires all the semiconductor and software and charging station to be upgraded. Makes no sense.
Bad Engineering Physics errors come from missing what is important: moving to higher voltages is really all about performance driving; significant charging advantages only come about as a bonus. Consider this: AC wiring needs to be safe not only up to rated supply voltages but also for switching power on and off, and especially for motors and other inductive loads where voltage surges need to go many multiples higher. For DC applications, we also expect to see nuisance over-voltages, in switching and beyond, wherever motors are ramping up and down under variable loads; but our primary concerns go further, to where desirable over-voltages come from regenerative braking, and where respective voltages routinely become extreme: keep in mind, most energy advantage in regenerative braking is always near and often beyond current BEV limits. Doubling operating voltage quite certainly gives real advantages in BEV design for performance: marketing regressive low voltage legacy technologies may work with non-technical business executives in the board room; not so much however in the real world of engineers and scientists.
cant they provide higher charging speeds with higher voltage easier ...
Higher voltage requires lesser amperage in operation. It is better but the time it would take to optimize it would make Tesla lag the other car maker if they switched to a higher voltage.
Lag like when they switched to hairpin windings too behind GM Etc? Its ok
@@aljones8519 lag as in lag in time. But you already got it.
Because Ohm’s law hasn’t change in 140+ years…….:kids😱
Wouldn't 400 volt system be safer for occupants ? ( Electro magnetic field wise)
Yes, in terms of electric shock risk 400 V is safer. The occupants aren't exposed to any significant fields.
400V is when human tissue ionizes and resistance drops. Current goes up substantially. So 400V is a good medium here. Although ideally there should sufficient safe guards like HVIL and Isolation detection so the occupants are never exposed to high voltage.