so here is a question for battery people when the battery is being discharged positive Li ions travel from the anode to the cathode for this to happen the cathode voltage must be less than the anode HOW does this occur since the cathode from an external circuit point of view is +3.6 v higher than the anode. I have asked this question on every battery video and no one has given me a straight answer IN FACT 100% of you tube Li Ion battery videos just gloss this over they just state the LI ions flow from the anode to cathode during discharge and I always ask why the hell would a positive Li Ion flow to a cathode that is has a positive potential with respect to the anode. So Stefan Rehnberg answer the riddle
The cathode voltage does not need to be less than the anode. When the battery is being charged the positively charged Li ions are attracted to the anodes negative charge. When the cell is being discharged the Li ions are pushed out of the graphite anode like a spring that is decompressing. The li ions once they go from the graphite anode back into the electrolyte are all bunched together and they repel each other. They diffuse into the cell by pushing against each other, and when they bump into an active intercalation site on the cathode they are absorbed and generate that positive potential. The tendency for the cathode to adsorb the lithium IS what creates the positive voltage. You can think of the voltage of a cathode as a way of measuring how much that material wants to adsorb the electrolyte charge carrier.
@@ferriswhitehouse1476 Hey Ferris thanks!!! by the way are you a battery chemistry guy just want to know so that I can trust what you are saying. So regarding discharge where does this spring force come from that propels the LI Ions up the potential hill to the cathode which is approx 3 volt higher than the anode? Also can you recommend a paper I can read on this mechanism? My background is semi conductors and IC design not Li Ion battery chemistry but I am really interested in what you have said!! thanks so much!!!
@@roger_is_red Im just a hobbyist so you shouldn't trust me lol, I'm pretty confident in my understanding, but you should be skeptical anyways. The li ions are not flowing up a hill that's not how you should think of it. They are more flowing down a hill and their speed/momentum down the hill is what is creating the voltage of the battery. The Lithium ions are positively charged, they are all bunch up at the anode when the battery is in a charged state. For every positively charged lithium ion there is a negatively charged ion usually PF6- (hexaflourophosphate) depending on the electrolyte chemistry. All the negatively charged ions will start out bunched up at the cathode. Its fairly intuitive that the negative ions will attract to the positive ones and if you left it to discharge long enough the electrolyte would balance out again will an even concentration of + and - all over the place. Important to remember the lithium isn't racing over to the cathode, its just dispersing itself evenly throughout the volume of electrolyte. Imagine a container full of salty water and you pushed all of the salt to one side of the container and held it there. As soon as you let go it would all disperse into the rest of the water naturally. Or a container full of gas, the gas will spread out through the container evenly.
@@ferriswhitehouse1476 So are u a hobbyist not really sure about your answer? So I am very familiar with diffusion this is how minority carriers transport across the base of bipolar transistor so that I get. I find interesting your point about the negative charge PF6 ions sitting over at the cathode that would indeed attract the Li Ions from the anode so these negative ions are sitting in the electrolyte at the cathode are actually reducing the voltage appearance of the cathode to a negative voltage allowing for the li ions to flow down hill instead of uphill if they were not there. So internally the cathode actually is negative with respect to the anode and this is due to the negative ions in the electrolyte. Any way I am rephrasing what you have said. and what do you think? does this rephrasing sound right? also point me to a tech paper I would appreciate it. I just find it funny that every youtube video totally does not get how this is not at all obvious and it's because they are just repeating someone who does not get the complexity
@@roger_is_red Yeah your summary sounds good, that's what i was trying to get across. When i was getting into this at first I had the exact same question about why the lithium ions were able to magically race over to the cathode. I couldnt find any crystal clear info on it either. And yeah every video on youtube you look for just shows the lithium moving straight from anode to cathode with no explanation. I don't have any specific paper to point you to unfortunately. But lots of papers on different cathode materials and processes refer to "diffusion coefficients" which makes me more confident that this is indeed how its working. Generally thin layers of cathode materials and high degrees of porosity increase the rate at which the battery can charge/discharge. It seems like information people dont think about to much, probably for battery chemists its sort of a fundamental things that doesnt need to be covered any more by the time you get to writing scientific papers. You might have more luck finding information on how super capacitors work and it would be highly analogous as far as ion transport from one side to the other happens.
uhhm ... no ... this is a 8s configuration with alternating orientation pouches where + and - tabs are being joined/clamped together. The green bars are isolators and only transfer mechanical clamping pressure. The last bit of the video illustration shows how to convert the pack to a 8s2p (doubling the capacity only). Think before you smear!
![FNAF Into the Pit has A LOT of Unused Graphics | LOST BITS [TetraBitGaming]](http://i.ytimg.com/vi/6YhZCRdipl4/mqdefault.jpg)
Brilliant! I might try this.
Hi dear sir do you supply this prismatic battery cell pouch In India
Great Idea, I love it. But also, those cells like to expand. Remember that if you ever decide to do this.
3D print files (.stl, .stp, etc.) posted anywhere (Thingiverse, etc.)? Thx!
did you find them?
@@krishnakumari2739 I did not
Best pressure contactor kit approach so far. Here's 2nd best ; ruclips.net/video/O3VtYwJz78g/видео.html
so here is a question for battery people when the battery is being discharged positive Li ions travel from the anode to the cathode for this to happen the cathode voltage must be less than the anode HOW does this occur since the cathode from an external circuit point of view is +3.6 v higher than the anode. I have asked this question on every battery video and no one has given me a straight answer IN FACT 100% of you tube Li Ion battery videos just gloss this over they just state the LI ions flow from the anode to cathode during discharge and I always ask why the hell would a positive Li Ion flow to a cathode that is has a positive potential with respect to the anode. So Stefan Rehnberg answer the riddle
The cathode voltage does not need to be less than the anode. When the battery is being charged the positively charged Li ions are attracted to the anodes negative charge. When the cell is being discharged the Li ions are pushed out of the graphite anode like a spring that is decompressing. The li ions once they go from the graphite anode back into the electrolyte are all bunched together and they repel each other. They diffuse into the cell by pushing against each other, and when they bump into an active intercalation site on the cathode they are absorbed and generate that positive potential. The tendency for the cathode to adsorb the lithium IS what creates the positive voltage. You can think of the voltage of a cathode as a way of measuring how much that material wants to adsorb the electrolyte charge carrier.
@@ferriswhitehouse1476 Hey Ferris thanks!!! by the way are you a battery chemistry guy just want to know so that I can trust what you are saying. So regarding discharge where does this spring force come from that propels the LI Ions up the potential hill to the cathode which is approx 3 volt higher than the anode? Also can you recommend a paper I can read on this mechanism? My background is semi conductors and IC design not Li Ion battery chemistry but I am really interested in what you have said!!
thanks so much!!!
@@roger_is_red Im just a hobbyist so you shouldn't trust me lol, I'm pretty confident in my understanding, but you should be skeptical anyways. The li ions are not flowing up a hill that's not how you should think of it. They are more flowing down a hill and their speed/momentum down the hill is what is creating the voltage of the battery. The Lithium ions are positively charged, they are all bunch up at the anode when the battery is in a charged state. For every positively charged lithium ion there is a negatively charged ion usually PF6- (hexaflourophosphate) depending on the electrolyte chemistry. All the negatively charged ions will start out bunched up at the cathode. Its fairly intuitive that the negative ions will attract to the positive ones and if you left it to discharge long enough the electrolyte would balance out again will an even concentration of + and - all over the place. Important to remember the lithium isn't racing over to the cathode, its just dispersing itself evenly throughout the volume of electrolyte.
Imagine a container full of salty water and you pushed all of the salt to one side of the container and held it there. As soon as you let go it would all disperse into the rest of the water naturally. Or a container full of gas, the gas will spread out through the container evenly.
@@ferriswhitehouse1476 So are u a hobbyist not really sure about your answer? So I am very familiar with diffusion this is how minority carriers transport across the base of bipolar transistor so that I get. I find interesting your point about the negative charge PF6 ions sitting over at the cathode that would indeed attract the Li Ions from the anode so these negative ions are sitting in the electrolyte at the cathode are actually reducing the voltage appearance of the cathode to a negative voltage allowing for the li ions to flow down hill instead of uphill if they were not there. So internally the cathode actually is negative with respect to the anode and this is due to the negative ions in the electrolyte. Any way I am rephrasing what you have said. and what do you think? does this rephrasing sound right? also point me to a tech paper I would appreciate it. I just find it funny that every youtube video totally does not get how this is not at all obvious and it's because they are just repeating someone who does not get the complexity
@@roger_is_red Yeah your summary sounds good, that's what i was trying to get across. When i was getting into this at first I had the exact same question about why the lithium ions were able to magically race over to the cathode. I couldnt find any crystal clear info on it either. And yeah every video on youtube you look for just shows the lithium moving straight from anode to cathode with no explanation. I don't have any specific paper to point you to unfortunately. But lots of papers on different cathode materials and processes refer to "diffusion coefficients" which makes me more confident that this is indeed how its working. Generally thin layers of cathode materials and high degrees of porosity increase the rate at which the battery can charge/discharge. It seems like information people dont think about to much, probably for battery chemists its sort of a fundamental things that doesnt need to be covered any more by the time you get to writing scientific papers. You might have more luck finding information on how super capacitors work and it would be highly analogous as far as ion transport from one side to the other happens.
Hahhahahahha... It will not work because you not connected all same polarity terminals toghter.
uhhm ... no ... this is a 8s configuration with alternating orientation pouches where + and - tabs are being joined/clamped together. The green bars are isolators and only transfer mechanical clamping pressure. The last bit of the video illustration shows how to convert the pack to a 8s2p (doubling the capacity only).
Think before you smear!