The LFP 4680 Battery Cell // + LFP with Tesla Silicon

The LFP 4680 Battery Cell  // + LFP with Tesla Silicon

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Welcome back everyone. I'm Jordan  Giesige and this is The Limiting Factor.   I made this video before the Q4 2021 earnings  call. And at that earnings call Drew and Elon   did make some comments in relation to 4680s with  LFP. So, I thought before we kick into the video,   it would be good for me to give my perspective  on what was said at that earnings call.  Let's start by working through the comments  that Drew and Elon made, and then we'll move   into the video. Drew said, quote, “To the  question about, should everything be 4680?  

It doesn't have to be. In the end, it's about cost  competitiveness and scalability of manufacturing.”  So my thoughts on that are: This gels with what  I'm saying. Throughout the video I talk about   there's…you could go with a 4680 or prismatic,  but there's trade off decisions that you have to   make. Now it's also worth noting that Drew's  comments were prompted by Pierre Ferragu’s   question. And his question was focused on outside  self-supply. So, Drew's comments don't necessarily  

apply to Tesla's in-house 4680 or whatever  form factor that they decide to use for LFP.  Drew continued on by saying quote, “There are  just some physics-based differences in what   happens in certain corner cases that would drive  different form factors. And we just have to be   cognizant of that and design to that.” End quote. As I said a moment ago, different form factors   have positives and negatives. Just  like you can change the thickness   of the electrode and a battery, so, or change  the electrolyte mix depending on if you're using   those battery cells for energy storage or high  power applications like vehicles. So, what drew  

might be suggesting here is that they might use  different form factors for different use cases,   such as mobility, like vehicles or energy storage. Uh, as I say in this video, uh, a 4680 form   factor, because it's smaller, it's  easier to thermally regulate. So,   they might use 4680s for their vehicles and  a prismatic battery cells for energy storage.  

And in fact, they, they still might be exploring  this. One interesting thing to note is that   it might actually change over time. Now, overall, as I say, in the video,   my preference is for Tesla to use the 4680  for everything, just to keep things simple,   but they do have these avenues open to  them. So, with that, let's move on to   Elon's comment, which is, “Yeah, we don't use  the 4680 at all for the Iron based cells.” 

This is something we already know from, from my  perspective, this was a present tense comment   by Elon, and it speaks directly to what  Pierre Ferragu’s question was, which is,   “Our outside suppliers all going to switch to a  4680 form factor for all their battery cells.” And   CATL already uses a prismatic LFP cell for  the battery cells that supplying to Tesla. So,   there's no reason for them to switch that up if  that's hitting costs and scalability requirements.  Now, that doesn't preclude other battery  cells or future manufacturing lines from   using the 4680 form factor for LFP or  nickel-based cells. It's just that, uh,   it doesn't have to be used for everything. And  they're currently not using the 4680 for the   cells they get from, for instance, CATL Now with all that out of the way,   let's kick into the video. There are two questions I’m consistently  

asked about when it comes to the topic of LFP:  “Can Tesla produce LFP in a 4680 battery cell”   and “Will Tesla produce LFP in a 4680 battery  cell?” The answer to the first question is easy:   Yes, all the technologies unveiled at  Battery Day are compatible with LFP,   so Tesla can produce an LFP 4680. The question of  will they produce and LFP 4680 is more complex,   but I think the answer is also yes. This video will cover how I came to   that conclusion, the benefits and drawbacks of  using a 4680 form factor, a roadmap for energy   density improvements, and why I think LFP  will become the dominant lithium chemistry.  Before we begin, a special thanks to my  Patreon supporters and YouTube members.   This is the support that gives me the freedom  to avoid chasing the algorithm and sponsors.   As always, the links for  support are in the description. 

First, for those who aren’t familiar with  what LFP means, it’s simply the abbreviation   of Lithium Ferro-Phosphate. Ferro means iron, so  what we’re talking about is an iron based cathode.   LFP’s primary benefits are that it’s cheap,  durable, and easy to scale. But it has a catch.  LFP batteries have low volumetric energy  density compared to commonly used Nickel based   chemistries, meaning they take up a lot of space.  To counteract the low volumetric energy density,   LFP batteries are typically large and use  a rectangular format known as prismatic.   Prismatic battery cells maximise the  rectangular shaped volume under the vehicle   so manufacturers can squeeze in more energy. This is as opposed to cylindrical cells which   have a maximum packing efficiency of about 78%  in a rectanguloid or cuboid box. This poses a  

challenge for Tesla because they’ve chosen a  cylindrical format for their in-house battery   cell production. The dimensions are 46 by 80mm  and it’s why they named the format the 4680.   So, the question naturally arises as  to whether Tesla will manufacture LFP   batteries in a 4680 format given that it has an  energy density handicap versus a prismatic cell.  CATL LFP Model 3s out of China are now getting  about 273 miles of range with a 60 kWh pack.   This is with a prismatic battery cell, which  has a theoretical packing density of 100%. Can   Tesla hit 273 miles of range with a cylindrical  format that has a 78% theoretical packing density?  First, although the theoretical packing  efficiency of prismatic battery cells is a 100%,   in reality, manufacturers like CATL only hit about  42% due to the steel bracing and other packaging.  Second, cylindrical battery packs like Tesla’s  achieve a 33% packing density. However,  

that battery pack was designed about 5 years ago  and also uses steel bracing, more fireproofing,   and other packaging such as modules. That is, just  by eyeballing it, it looks to me that if Tesla can   strip out the steel bracing and some of the other  excess packaging, they should be able to match the   energy density of a CATL LFP battery pack. As we know, stripping out the steel bracing   and excess packaging is exactly what Tesla is  attempting to do with the structural battery   pack that they unveiled at battery day. Let’s  run the numbers on a structural pack with LFP.   Sandy Munro indicated that a structural  battery pack using the 4680 could   fit 960 cells under a Model 3. To double check Sandy’s claim,   I checked with Alex Tourville, who’s done a lot of  work and given some great presentations covering   4680 cell and pack design on the Official X  Pod YouTube channel and on the Callin app.  He indicated that the maximum pack size would  depend on safety margin and pack orientation   and could be anywhere between 912 and 1064 cells  for a Model 3. What that in mind, I think Sandy’s  

guess of cells is a good middle ground. How  much energy will each of those cells contain?  The 2170 battery cell used in the Model 3 and  Y stores roughly 18 Wh of energy. If a 4680   cell stores 5x the energy due to its larger  volume that would mean a 90 Wh battery cell.  

Again, I’m being conservative here. The 4680  has nearly 5.5 times the volume of a 2170 cell   rather than 5x the volume. Let’s convert that 90  Wh Nickel cell into a comparable LFP battery cell.  In terms of volumetric energy density, Tesla’s  Nickel based 2170 battery cells are 720 Wh/l   while BYD and CATL LFP are maxing out at 450 Wh/l.  That is, LFP has roughly 63% of the volumetric   energy density of the 2170 nickel battery cell. 63% of a 90 Wh battery cell is 56 Wh per battery   cell. 56 Wh times 960 battery cells is 54 kWh.  54 kWh is roughly the same size as the pack on  

the 2021 standard range plus Model 3 LFP vehicles  from China, which achieved 253 miles of range.  So, the answer to the question “Can Tesla make  a 4680 cell using LFP?” gets a yes from me,   because it looks like they can make a  battery pack that satisfies Tesla’s 250 mile   minimum range requirement. Furthermore, I was  conservative in most of the estimate steps,   which leads me to believe that Tesla could  overshoot 250 miles of range with LFP   in a 4680 form factor. More on that in a moment. Is there any indication from Tesla that they’ll   use the 4680 for LFP? Yes…ish. Tesla unveiled the  LFP chemistry in the same presentation that they  

unveiled the 4680 battery cell. Then, at the end  of the presentation, Drew Baglino said that the   benefits of Tesla’s structural battery apply to  an iron based cathode the same way they apply to   a nickel based cathode. That is, Tesla didn’t  explicitly say they’d use the LFP in a 4680,   but my view is that this was implied  because the structural battery uses 4680s.  But why does it matter whether Tesla  can use LFP in the 4680 form factor?  If Tesla didn’t use the 4680 for their LFP battery  cells, it would require the design of new battery   cells and packs as well as the manufacturing  lines to make those battery cells and packs.   That is, using different form factors  for different chemistries would add   complexity to Tesla’s cell manufacturing  operations, which runs counter to Tesla’s   tendency to reduce manufacturing complexity. Furthermore, those who don’t think that the 4680   form factor’s viable for LFP and want to see Tesla  do prismatic LFP may be placing too much emphasis   on energy density. Although prismatic battery  cells do offer higher theoretical energy density  

than cylindrical cells due to their better packing  efficiency, they also come with a draw back.  They tend to have low surface area for a given  volume. This makes regulating the temperature of   prismatic battery cells more difficult for  both high and low temperature performance.  LFP is robust to high temperatures, but as LFP  chemistries become more energy dense and the   prismatic cells are packed more tightly, prismatic  battery cells may hit a thermal limit. That is,   there may come a point when prismatic cells reach  a high enough energy density and packing density   that a smaller battery cell becomes necessary  to prevent degradation issues from trapped heat. 

As for low temperatures, in my LFP science video  I showed that LFP battery cells perform best   when pre-heated. 4680 cells will have a smaller  internal volume than prismatic battery cells,   which may allow for quicker pre-heating of  the 4680 battery cell in colder climates.  What if I’m wrong, and Tesla  can’t make the 4680 work with LFP.   Could Tesla make a prismatic LFP battery  cell? Absolutely. As I said earlier,  

it would just require further investment into R&D  and separate battery cell lines. The question is,   would that be the best use of Tesla’s engineering  resources and would they be able to recuperate the   R&D expenses. Those are two questions I don’t  have an answer to and they’d be tightly linked.  Let’s press on and look at the full potential  of a 4680 cell using LFP. As I said earlier,   250 miles of range with a Tesla LFP 4680 cell is  the base case. If we take into account that I was  

conservative and that Tesla might have a trick  up their sleeves with the thick DBE cathodes I   talked about in the secret sauce video, they might  be able to get that to 275-300 miles of range.  What about beyond 300 miles of range?  Let’s look at high loaded silicon anodes.  By a high loaded silicon anode, I mean adding  5-30% Silicon to the graphite normally used in a   lithium ion battery anode. This is versus the 0-5%  silicon commonly used in graphite mixes today. To  

keep things simple, I’ll refer to the 5-30% high  loaded silicon anode as a high silicon anode.  I’ve covered silicon doping of LFP a couple times  in the past, but my view continues to develop on   the topic. My original view was that Silicon would  handicap one of the biggest benefits of LFP, which   is high cycle life. LFP is good for 3000 cycles  and beyond, which makes it perfect for commercial  

applications like energy storage and Robotaxis. Meanwhile, Silicon struggles to hit 1000 cycles   in a battery anode due to issues related to the  expansion and contraction of the silicon. That is,   why kneecap the cycle life of LFP for additional  energy density when the primary use case would be   Robotaxis and energy storage, where cycle  life plays a large role in the economics.  Furthermore, LFP battery cells are, so far,  unprofitable to recycle because the value of   the iron in LFP batteries is low. With Nickel  based battery cells recycling makes more sense   because Nickel is more than an order of magnitude  more expensive on the open market than iron. 

Because the recycle value of LFP is so low,  my view was that the cells would be trashed   at the end of life rather than recycled. It that  were the case, it would make sense to leave out   the silicon to maximise cycle life, which would  reduce the carbon impact of a single life cell.  However, for several reasons, I’m now getting  more bullish on Silicon for LFP batteries.  First, on the recycling front, JB  Straubel is giving recycling a big   push with Redwood Materials, and I think  his involvement will accelerate scaling   and therefore improve the economics of recycling  LFP batteries. By the time LFP batteries start  

coming off the road in about 10-15 years,  recycling LFP batteries might make economic sense.  Second, somehow, I missed a bombshell comment  from Drew at Battery Day in the Q&A section.   Drew stated that Silicon is a key part of  the roadmap for iron based cells. That is,   Tesla has stated they plan to use Silicon in their  in-house LFP battery chemistry using the 4680.   I see two potential technology pathways here: First, a single chemistry pathway where high   silicon anodes are used in all of Tesla’s in  house LFP battery cells. This would happen   if they’re able to achieve 3000+ cycles with  Tesla silicon, which would match the 3000+ cycle   life that LFP is capable of. If Tesla silicon  achieves anything less than around 3000 cycles,  

it would limit the cycle life of the entire  battery cell to the cycle life of the silicon,   which brings us to the second pathway. If Tesla hasn’t fully cracked the Silicon   code, they may manufacture two different LFP  chemistries. First, a workhorse LFP chemistry   using no silicon that offers 3000+ cycles for  energy storage products. Weight and volume aren’t   a primary concern for energy storage products and  the silicon wouldn’t be needed. Second, a mobility   LFP chemistry using a high silicon anode  that offers around 1,000 cycles for vehicles. 

Silicon would reduce the weight of battery cells  and therefore the weight of Tesla battery packs,   which would increase range, but there would be  a hit to cycle life. However, 1000 cycles would   still be acceptable. 1000 cycles would mean around  a 300,000 mile service life on a vehicle with   more than 300 miles of range. A 300 mile range  vehicle should be no problem for LFP if it has   a high silicon anode. More on that in a moment. Will Tesla take path A or path B? My guess is   that Tesla hasn’t fully mastered the durable  silicon required for 3000+ cycles because it’s   such a difficult problem to solve. Meaning I  think they’ll take path B and pair their LFP   cathode with two different anode options. This is  much the same way slightly different electrolyte  

formulations and electrode thicknesses are often  used in the battery industry for high power,   high energy, or high cycle life cells. If Tesla does have high cycle life Silicon,   I’ll be gobsmacked and be happy to be wrong.  Going from the 0% Silicon used in current LFP   chemistries to 5-30% Silicon with high cycle life  is like skipping the amphibian stage in evolution   and going directly from fish to lizard. Regardless, the key takeaway here is that  

Drew indicated that they plan to use Tesla  Silicon in Tesla 4680 LFP batteries, which   will expand the scope of use cases for LFP and  open the door to long range LFP based vehicles.  How much would high silicon anodes  increase range for LFP based vehicles?   On our base case 250 mile range vehicle, a  high Silicon anode would increase range by 20%   to 300 miles of range. However, there are three  things worth considering along with that estimate:  First, the range boost probably wouldn’t  happen all at once. Tesla would likely  

titrate Silicon into their LFP chemistries  over the course of a few years. Second,   the 250 mile base range was conservative.  If Tesla can hit 270 miles without silicon,   they could eventually hit 325 miles of range or  more in the mid-2020s with a high silicon anode.  Third, LFP’s already poised for dominance in  energy storage products because of its high   cycle life and low cost AND it’s already making  great inroads into short range and mid-range   vehicle segments. If Tesla was able to achieve  325+ miles of range with a high silicon LFP  

chemistry, LFP would gain dominance  in both grid and automotive use cases.  With that in mind, it quickly becomes clear  why Elon has said that the ratio of iron to   nickel based battery cells will be 3:1 or more.  At Battery Day, Tesla indicated that the energy   storage market is worth 10 Terawatt hours and the  transportation market is worth 10 terawatt hours. 

A 3:1 ratio would be 15 terawatts  of LFP chemistries and 5 terawatts   of Nickel chemistries. In 2021 about 100  GWh of LFP battery cells were produced,   which means the market for LFP could grow by 150x  in the next 15 years or so. It’s worth noting that   I’m purposely leaving Sodium ion batteries out  here, which’ll be covered in a separate video. 

Earlier I said that LFP with a high Silicon  anode could easily hit 300 miles of range but   325 miles or more was certainly possible.  I also said that my definition of a high   silicon anode was 5-30%. Clearly, LFP  has even more runway beyond 325 miles.  On Twitter, Matt Lacey did some rough calculations  for LFP when paired with advanced anodes and   electrolytes. At the cell level, with 25% Silicon,  the energy density was around 500 Wh/l. With 100%   Silicon or lithium metal, it was around 600  Wh/l. For reference, Tesla’s Nickel based 2170   chemistry used in the Model 3 and Y is 720 Wh/l. However, these numbers are all at the cell level.   Typically, LFP batteries require less packaging  material because it’s a safer chemistry than   Nickel. Plus, we need to factor in that by  the time we see these advanced chemistries  

in the late 2020s, there’ll be further efficiency  improvements throughout the power train. With all   that in mind, my view is that an LFP 4680 battery  pack could eventually provide 400 miles of range.  As a side note, with other LFP form factors  such as the BYD Blade, it could be possible   to hit 400 miles of range without 100% Silicon  anode or lithium metal. This is because prismatic   based battery packs have a higher theoretical  energy density than cylindrical based packs.  However, Tesla’s efficiency is several  years ahead of Chinese manufacturers.  

With so many variables in play, If Tesla  does manufacture LFP based 4680s, it’ll be   an interesting case study to watch the competition  between Chinese made prismatic LFP based vehicles   vs Tesla made cylindrical LFP based vehicles. With all that said, form factor may be an academic   point. First, Tesla can always develop  an in house prismatic LFP battery cell.   From a customer perspective, does it really  matter whether the battery cell looks like   a SPAM can or a Campbell’s Soup can? Second, Tesla’s already purchasing   prismatic LFP battery cells from CATL and  will likely be purchasing them from BYD.   That is, even if Tesla does use the 4680 for in  house LFP cells, many of their vehicles will be   using prismatic LFP and it’s unlikely Tesla would  allow all those vehicles to have much variability   in their performance characteristics. So again,  the difference would be transparent to customers.  Are there any barriers to Tesla adopting LFP?  None that I can see besides developing and   qualifying a new LFP cathode material.  As I covered in the LFP Patents video,  

the patents should be expired by April of 2022.  My guess is that Tesla could deploy LFP in 2023   to 2024 after they have their first Nickel  based production lines up in Berlin and Austin.  Are there any barriers for other auto  manufacturers looking to adopt LFP for their   electrification efforts? For western automakers  that are expected to offer mid to long range   vehicles, definitely. Every other automaker  has an efficiency about 20% less than Tesla’s,   and in most cases that’s being generous.  Instead of 273 miles of range from an LFP   pack, they’d get about 218 miles of range. That 20% efficiency handicap could spell disaster   for some of these companies because they’ll be  forced to use Nickel based battery chemistries   instead of LFP. Nickel is difficult  to source and supply shortages are  

expected throughout the decade, meaning  shortages of Nickel based battery cells.  Shortages of Nickel based battery cells may mean  that if a manufacturer can’t adapt and use an LFP   based battery pack, their electrification efforts  may fail because they simply won’t have the   batteries they need to make vehicles. Furthermore,  LFP battery packs are 20% cheaper than Nickel   based battery packs, which gives manufacturers who  can use LFP battery packs operational head room. 

In short, electric vehicle efficiency may  determine whether some EV makers survive   or go bankrupt in the 2020s. Tesla’s been  working on their core vehicle efficiency   for about 15 years, which allows them to use fewer  battery cells in each vehicle, increases margins,   and opens up more chemistry options and therefore  a larger cell supply to ramp vehicle production.  With regards to Chinese manufacturers, their  domestic market isn’t as demanding for range   and I expect the efficiency of Chinese vehicles to  increase rapidly, which’ll make them competitive   in North American and European markets.  That is, Tesla and Chinese manufacturers   seem to be the best positioned with LFP. Let’s wrap things up. The Tesla 4680 cell   is compatible with an LFP battery chemistry  and should provide a range similar to the   current LFP variant of the standard range plus  model 3, at around 250-260 miles of range.   This is true even with a conservative  estimate and before factoring in potential   energy density improvements from silicon. 250-260 miles o f range is a minimum.  

In the next few years, Tesla could achieve 300  miles of range with LFP in the Model 3 with a   moderate loading of Silicon, 350 miles of range  in the mid-2020s with a high silicon loading,   and eventually 400 miles of range fully evolved  with a 100% silicon anode or lithium metal anode.  Prismatic battery cell formats do have some first  principles advantages but, as Tesla indicated at   Battery Day, if more range is needed, they can use  one of their other chemistries. Nickel will remain   the premium chemistry for range and performance  and LFP will be the work horse. Why develop an   entirely new cell and pack architecture if you  can just change your cathode coating mixture,   at any of your factories, at any time, from a  Nickel coating to an LFP coating, and vice versa. 

It’s a little more complicated than that, but  that’s the general idea. Changing the coating   mixture versus tens, possibly hundreds of millions  of dollars of R&D expense. From a technology   standpoint, a prismatic LFP cell could leverage  most of the technology unveiled at battery day,   but it still wouldn’t be cheap to develop. I’m not sure if the tabless electrode could be   used, but it might allow Tesla to make a large  prismatic cell with good thermal regulation.  

Regardless, if a prismatic form factor allows  Tesla to recuperate the R&D expenses, they’ll go   prismatic for in house LFP. I don’t imagine the  savings would be large, but every penny counts.  What about cost? How cheap will  Tesla LFP battery cells be?  As discussed in the BYD blade battery video,  prior to the current bout of inflation, a CATL LFP   battery cell cost about $88/kWh at the pack level  whereas the BYD blade battery pack costs about   $65/kWh. Tesla’s cost would be at or below the  cost of the BYD blade battery pack when they hit   scale. This is because Tesla will have the  advantage of a higher throughput on their   battery cell lines and won’t be paying a margin to  a third party for the cells they produce in house. 

That is, I’m expecting below $50 per kilowatt hour  at the pack level around 2025, possibly as low   as $40 per kilowatt hour at the pack level. That  comes with a big caveat - that Tesla can get their   materials cheaply. Battery materials are currently  running short and there’s inflation in the market.  What’s the price floor for LFP batteries?  My guess is perhaps as low as $20-25 per   kilowatt hour at the pack level by the  mid twenty thirties. It would take an  

entire video and some cost modelling to prove  that out, and there would be some significant   potential error bars, but I think it’s doable. Regardless, LFP batteries are inherently cheaper,   and the materials are more widely available. That  is, the cost and scalability of LFP will make   electric vehicles affordable and widely available.  For those manufacturers that lag on efficiency,  

it may be more difficult to use a lower  energy density chemistry like LFP, and it’ll   make their scaling efforts more difficult. Tesla’s been preparing for this moment for   decade and has the efficiency and adaptability  to incorporate LFP into their line up rapidly,   where it will eventually displace  Nickel as their go-to battery chemistry.  In the next video of the LFP series, I’ll wrap  up the entire LFP series with a summary video.  If you enjoyed this video, please consider  supporting me on Patreon with the link   at the end of the video or as a YouTube member.  You can find the details in the description,   and I look forward to hearing from you. A special thanks to Mike Gabrys,   Dave Fitzhugh, James (The Illustrious)  Douma, Asbjørn S. Tunheim, Stefan Sommer,  

and Chan Nguyen for your generous support of the  channel, my YouTube members, and all the other   patrons listed in the credits. I appreciate  all your support, and thanks for tuning in.

2022-02-10 13:15

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