How are cylindrical, prismatic, and pouch style battery cells different?

This is a portion of a conversation with PhD scholar Ravindra Kempaiah. We dive deep into the process of battery raw materials, how they're manufactured into battery cells, energy density, and future battery tech. Watch the entire two hour long conversation here: • How Tesla batteries wo... .
*******
Tesla referral code: ts.la/sean510
Become a Patreon supporter: / seanmmitchell
Like Tesla: / liketesla
Now You Know: / nowyouknowchannel
Hyperchange: TV / hyperchangetv
Teslanomics: / @bensullinsofficial
Products I use:
Canon 80D: www.amazon.com/dp/B01H8CWRBM/...
JOBY GorillaPod 3K Kit. Compact Tripod 3K Stand and Ballhead 3K for Compact Mirrorless Cameras or Devices up to 3K (6.6lbs). Black/Charcoal: www.amazon.com/gp/product/B07...
Rode VMGO Video Mic GO Lightweight On-Camera Microphone Super-Cardioid: www.amazon.com/Rode-VMGO-Ligh...
Michelin X-Ice Xi3 Winter Radial Tire - 245/45R19/XL 102H: amzn.to/2DyiHUc
iOttie Easy One Touch 4: amzn.to/2Bs3SR6
KobraTech Mini Cell Phone Tripod: amzn.to/2sJMOH2
#Tesla #ModelS #ElonMusk

[@DavidDrivesElectric]

BTW, it is also incorrect that when one cell in a Tesla pack is failing it s impacted only by 1/7000. In a battery pack the weakest link determines the capacity of the entire pack. There are 96 bricks in series. If one cell fails, the effect is 96 times as much as this one brick is now the weakest link and limits the capacity of the entire pack. Another statement that isn't quite true is the load on each cell in high power drain situations. Yes the power is divided between 7000 cells vs 300 but those 7000 cells are also much smaller. That's why the 'C' factor is used when describing load on batteries. Instead of absolute power numbers, what really matters is the ratio between cell capacity and power draw. C1 means the power draw is equivalent to the cell capacity in Ampere. C1 on 7000 small cells is exactly the same load as C1 on 300 cells that are larger. And that's what matters to a cell.

[@andrasbiro3007]

I'm pretty sure the BMS can isolate failing cells, or at least bricks. In practice Tesla batteries degrade very very slowly, so regardless of how this works, it's definitely not an issue.

[@DavidDrivesElectric]

@@andrasbiro3007 the BMS can't isolate cells not bricks. But even if it could, that would make no difference. A single lost cell is always multiplied by 96 in terms of capacity loss.

[@andrasbiro3007]

@@DavidDrivesElectric Look into the Tesla BMS, and the overall structure of the battery. I'm pretty sure each cell is individually managed. I looked up the details. I found very little about the Model S battery, but it seems to consist of ~7100 cells. 96 cells work in parallel in a brick, and bricks are connected in a series. That's 74 bricks. If Even if each brick has to be at the same voltage, that means each dead cell counts as 1% capacity loss. Not the end of the world. But if they are managing each cell individually, one cell failure is just 1/7100 capacity loss, which is nothing. I'm not sure about the Model S, but the Model 3's BMS definitely manages cells individually. kzbin.info/www/bejne/ipW4ooSQeJeXmac teslamotorsclub.com/tmc/threads/effect-of-a-cell-failure-on-the-whole-battery-pack.95480/ insideevs.com/news/338947/expert-says-tesla-model-3-battery-pack-is-most-advanced-ever-produced/ But the very slow degradation of Model S batteries suggests that it also manages cells individually. It's not just about dead cells, but cell imbalance, which seriously reduces battery life.

[@DavidDrivesElectric]

@@andrasbiro3007 It is physically impossible to manage single cells the way the battery packs are designed. This is true for Model S/X/3.

[@andrasbiro3007]

@@DavidDrivesElectric This is the most detailed description of the Model 3 BMS I could find : evtv.me/2018/05/tesla-model-3-gone-battshit/ And reading it carefully, I found that what this article calls "cell" is actually a "brick" consisting of 96 cells. So probably this is the source of the confusion. Anyway, that's still sufficiently fine grained control to make rare cell failures mostly irrelevant.

[@phonzy]

I love educational videos haha what a treat, thank you both for the knowledge

[@FamilyFirstJ]

I needed this...I didn't know I did, but im glad you made this video

[@Infinity_Squared]

Calling it, this video is about to get wayyyy more than is current 5k views. Thanks for the information!

[@farukcarushi4983]

He didn’t say anything about prismatic batteries. I think prismatic batteries are in my Fiat 500 E. I was kind of looking forward to learning about that.

[@csteve360]

very useful info on cylindrical and pouch cells ..... what can you tell me about prismatic cell?

[@KenHeslip]

It's almost like traditional car companies are deliberately giving their customers inferior batteries. 🤔

[@MrTiomanu]

the cell is cheaper, but termal management is expensive. Pouch has much more heat transfer area

[@Alrukitaf]

One down side of cylindrical cells is the weight. The rigidity of the cylindrical cell gives no contribution to the structural strength of the vehicle because the safety regulations state that the battery pack cannot form part of the chassis; it has to be a separate structure. There is an advantage in cooling, but pouch cells can withstand more of the inevitable swelling of the electrodes. Pouch cells will come down in cost as faster cycle times are achieved through innovations in the manufacturing process. So that would explain the preference for pouch cells with so many manufacturers. Also, if a cell in series with a whole bunch of other cells “goes bad” the whole section is affected, so the impact of one cell going bad is not as much of an issue as stated.

[@KingLutherQ]

1) Best in cost per KwH: Cylindrical 2) Best KwH per weight: Pouch 3) Best in temperature management: Cylindrical 4) Speed of battery production: Cylindrical Why did GM choose pouch? Maybe they could not balance the voltages of cylindrical cells as Tesla did.

[@SeplosTechnology]

Very professional explaination.

[@theflew]

#3 is wrong. Pouch cells have more surface area to cool without hot spots like cylindrical cells. The Volt's back was way overkill in the cooling department.

[@rogerstarkey5390]

Rivian said they were using 2170?

[@AllThingsEV]

Yes

[@shawn1260]

Other companies are probably using pouch cells because they are cheaper to assemble into a battery even if the cells are more expensive. Tesla has perfected the assembly of cylindrical cells into batteries. So Tesla can take advantage of this cost savings due to there manufacturing expertise.

[@teunlll]

so whats the differense between pouch and prismatic cells?

[@CarbonGlassMan]

Does anyone know the amp discharge rating of the 18650 cells Tesla uses? Like DeWalt battery packs have a 20a discharge rate, meaning they can safely and continuously output 20 amps to the tool for long periods of time.

[@geraldkoth654]

Cost of material is usually the smallest part of a vehicle. Labor is the primary content. So Tesla is not unionized, does not pay union scale and is not required to have at a minimum three workers per shift to put out what one worker not in the union can produce. 7000 connections and numerous assemblies are cheaper for Tesla than 200 connections and less assemblies for an auto maker already ruined by unions. I have always used pouch packs for my electric vehicles, they are more space efficient, since even with hexagonal closest packing cylindrical cells have a lot of air included in the pack. As far as cell stress with massive amounts of current required during acceleration, the area of the active chemicals is what provides the current. As well the internal resistance of the cells will influence the efficiency of the cells both from the old I squared R and from peukert factors where capacity is lower for high draws than for lower draws. Prismatic cells are just prepackaged pouch cells with lots of extra added weight and volume. Great for DIY assembly or for batteries with few cells in series. For high voltages used in vehicles, the prismatic cell is just way too bulky and difficult to cool.

[@DavidDrivesElectric]

As JB Straubel once said, the packaging isn't important, but what's inside. Tesla doesn't have a cost advantage because cylindrical cells. They are producing far far more than any other EV companies thus they can produce cheaper. Tesla's success is stunning, but it is not due to the cylindrical cells form factor. That has purely historical reasons. When they started production capacity was mostly available for cylindrical cells. Tesla designed their battery packs around those cells and got that to work really well, so they continue that way rather than starting their battery pack design from scratch. The other reason Tesla is ahead in batteries is because they push their batteries way more than others. They might have pushed too far as we can see now with the old 85 packs which are now severely crippled by Tesla in terms of charging, performance and also capacity.

[@emreucar3322]

Dear Ravindra, why did you focus on cylindrical battery cells?

[@brolls2735]

Wow very insightful information from your guest. I knew there had to be more to why Tesla batteries don't degrade and get such a long cycle life. Thank you for putting this interview together.

[@jaycarneygiants]

Do the pouch batteries have more charge cycles in their lifetime?

[@maitrick1963]

Hello Sir, How does the battery content change with a change in battery shape? that is, is there any difference in the active material of the Cathode if the same battery is cylindrical or prismatic?

[@kt9aq]

No, the battery chemistry is independent of shape. The difference is the shape of the electrode.

[@DougJessee]

Just something not mentioned: When manufacturing, a single cylinder cell being tested as 'weak' is easily swapped for one that matches the others in the module BEFORE the module is built.

[@relentlesskst1231]

why don't you do a video on glass batteries? since it is the future

[@brittennz]

Sean, thanks for the video. However several other resources including Sandy Monro highlighted that the paunch cells are more cost effective than the cylindrical. I wonder why this gentleman say the opposite

[@AllThingsEV]

Though I don’t have any data to back it up I’d take a guess to say Tesla cylindrical battery packs are very complex to make and therefore more expensive, pouch are not because it takes less time to manufacture. The individual cylindrical cell *is* less expensive than pouch. I may have covered this in a previous video back in August or September.

[@rzee4331]

@@AllThingsEV I'd agree cylindrical-based packs are more complex and more expensive to make * in low volumes *. By designing and owning their own battery pack lines, Tesla's battery pack cost per kWh is probably much lower than pouch-based packs that others buy from Samsung & LG.

[@melllvar4262]

Perhaps they don't have a practical method for producing cylindrical cells en masse.

[@mrgcav]

Needs an update

[@Nikki-4-President]

I think the pouches are lighter

[@TheSn1per]

possibly the cylindrical cell is still cheaper due to reason like the VHS tape. demand and supply. those 18650's are damn near everywhere. not simply cheaper to build. imho..

[@rogerstarkey5390]

Sean Read the battery pack patent!

[@raymondcasso7966]

Oh I dont know why everyone uses pouch cells... packing efficientcy???????

[@Mr_Battlefield]

I seen a video that a electric vehicle company called "xos" or sox or what ever is using Cylinder batteries for the vehicles there building. I'll find the video.

[@Mr_Battlefield]

kzbin.info/www/bejne/pIOldp6ef8ydicU

[@QUADBOYification]

I do disagree, pouch cells are way more capable of discharging high current. There is way more material in a pouch cell than in a 18650 cell. Especially bike batteries are made of pouch cells because they are manufactured in longer flat sizes and fit a canister way better. Cooling is also way better because it's a larger area to have direct contact with metal casings. I have seen 3.7v 200Ah pouch cells that are way smaller than prismatic equivalent cells. The weight is half of 18650 equivalent batteries. I have also read a new study that claims you get twice the cycle life if you compress a pouch battery into a strong metal casing so it can't expand. So, 1000 cycles for a 3.7v lithium ion pouch battery.

[@crosscarlisle3077]

Seems like you and I are on the same page. We should start an ebike business together. If these pouch cells are actually capable of the amp hours they claim, then we can become very rich men. It would only be the beginning.

[@turbosupra2jzdragracingtob249]

7000 vs 300 is one comparison makes the cylindrical cells more labor intensive. Cylindrical cells life span drops to 0% and pouch cells life span drops only to 80%. So they would rather sell replacement batteries in future…

[@ReevansElectro]

My BS meter keeps ticking up during this whole presentation. Cylindrical cells are better, cheaper and yet nobody uses them except Tesla and Rivian?

[@yehudagoldberg6400]

Tesla has the technology to properly manage 7000 cells, other OEMs which are not tech companies do not have the technology to manage so many cells so they opt for the easier-to-mange option.

[@waynelewis9110]

Definitely believable. I mean, Tesla is not an inexperienced company. They have no experience making ICE vehicles, but that is irrelevant. They’ve been mass producing EVs for almost 8 years now, and have been developing and improving the tech needed to do so for 12+ years. They have years of experience in solely being focused on EV development, unlike traditional automakers. Tesla has positive margins on all of their vehicles. Rivian is using cylindrical cells most likely due to the fact that they’ve been working on their tech for 10 years, also solely working on EVs, not ICE. As stated from the video, Tesla’s vehicles are built from the ground up to be electric, same with Rivian’s vehicles. Many traditional automakers’ EVs are based on ICE vehicle platforms and/or were not worked on for as long as they needed to be, especially in comparison to Tesla and Rivian, in order to properly utilize cylindrical cells, so they use pouch instead. Legacy automakers have been launching EVs as either compliance cars, or most recently, a rushed reaction to Tesla’s apparent dominance of the EV market, which they now acknowledge is the future. Prime example is the Ford Mustang Mach-E. I like the car, but if you read about it, Ford pretty much has admitted that the Mach-E was going to be a compliance car at first, but then they did a complete design and architectural overhaul over the course of 2 years to make the car a serious competitor to ICE vehicles as well as EVs. In short, the Mach-E was relatively rushed, as with many legacy automaker EVs.

[@ReevansElectro]

@@waynelewis9110 Cylindrical cells are better, cheaper and yet nobody uses them except Tesla and Rivian?

[@waynelewis9110]

Robert Evans Yes, Tesla and Rivian are the only ones. Cheaper + better != easy/easier to utilize. Hence why Ford jumped on investing in Rivian to use their skateboard platform in some of their future EVs instead of developing their own. Using cylindrical cells in a battery and power train platform in EVs appears to require expertise in software (for BMS), proper cell chemistry, electric motors, and major investments in actually developing the required platform instead of talking about it. The Ford Mustang Mach E uses pouch cells, and despite starting at $43k, it’s going to be $4k more than the starting price of the Tesla Model Y. Ford will be building Mach Es in Mexico, utilizing a ton of robots. Yet they are still going to experience anemic margins on Mach Es despite this. In contrast, all Tesla Model Ys sold in the US will be produced in the US, and Tesla will experience healthy margins on Model Ys. A testament to their hard work on honing cylindrical cells + electric power trains, which made them cheaper to produce and utilize.

[@ReevansElectro]

@@waynelewis9110 You are aware that Tesla released all their patents to the public, aren't you?

[@carljaekle]

Don't cylindrical cells also have more surface area, making thermal management easier?

[@ronalaska2472]

My 2013 Focus Electric has degraded to 75 miles from about 90 I wish I had cylindrical cells!

[@mrknesiah]

The biggest advatage of cylindrical is that it can be pushed the hardest due to the natural strength of it’s coiled structure encased in a metal tube. Pouch cells will be cheaper to manufacture in volume due to their simple and flinsy structure but they are not suitable for high performance applications.

[@Foxfried]

They Indian guy is completely wrong, the ONLY REASON to use pouch cells is because they have a higher charge & discharge rate, Easily can be charged at 2-3C and pouch can be drawn at 10-20c where as you can not do that on traditional cylindrical cells. Cylindrical struggle to do more than 3c.

[@danielc3453]

Could it be that G.M doesn't want to make EVs? They didn't want to make small cars for years and the results were the Chevette, Cavalier and the Sonic.

[@leysin]

How are the Tela battery more "favorable" when only Tesla is the only one using them. Every other automakers are using the prismatic cell or pouch cell. You have no idea and just making subjective claims with no proof that Tesla batteries are better.

[@eyeswideshut2800]

Horrible video, stay on track, everyone is not building a car.

[@YoursNKR]

Nothing here about prismatic cells!! Hence my dislike!