The 100% Graphite Silicon-Free 4680 Anode // What are the Implications?

[@thelimitingfactor]

Note 1: I think if anything is delaying Tesla Silicon, it's the issues Tesla has with the dry coating process rather than the Silicon itself Note 2: One person (Dr. Juho Heiska) has noted that it's most likely the tabless electrode providing the extra power that Sany mentioned. I agree!

[@larrypeters8638]

⁰0

[@celsostarec6735]

Please note Tesla MUST qualify batteries for the heavy duty semi trucks that NEED to endure. This HD application is far more demanding than typical in cycle life, both in total SOC excursion and possibly going to the limits of SOC. (SOC - State Of Charge of each cell). Qualifying pure carbon cathode first is a prudent move, as the semi cannot turn into a Bolt style flop without endangering the company. Prudent move. Reasonable move. As Tesla perfects (and thoroughly tests & qualifies) it's silicon enhanced cathodes over time current choices could be overcome.

[@joeyang9475]

@@stefanweilhartner4415 Is the silicon nanowire technology the same as that from Amprius' silicon nanowire?

[@lifewalk244]

@@celsostarec6735 I think they do not go to the limits of SOC. Especially for HD applications: 1.) Limiting the SOC range (smaller DOD) allows more cycle life and less degradation. They maybe will use it for qulification in order to create nore harsh conditions but not during real truck generation. Voltage window (SOC range) has much impact on lifetime 2.) One thing where they would need to find the balance is to be able to gurantee the power needed to propel the truck especially at the edges of the SOC window. This is tough to do especially at cold temperature. 3.) In order to qualify the cell they will probably will use much higher C-Rates then will actually be usued during operation (e.g. 1C/1C) 4.)

[@gridcoregilry666]

Jordan, your videos are really something special. The level of sophistication is insane! From the slide design, research, script, reasoning to simply everything. Glad to have you on board, helping people to understand and eventually support Tesla's mission.

[@thelimitingfactor]

Hell yeah man! Glad to hear it.

[@DanielZajic]

Great job, thanks for the hard work you put into these. You're keeping the Tesla investor community (I'm basically all in) and a lot of other people well informed about the industry.

[@thelimitingfactor]

So much more coming. Really excited about this thermal management video 🤠

[@mtran1980]

Thanks!

[@grahambrown42]

Great stuff Jordan and simply explained thanks 🙏

[@thelimitingfactor]

You're most welcome Graham!

[@NickoSwimmer]

Hey Jordan! I loved the video as usual, and my God your CAD animations are incredible. Really helps convey the physical material transformation. I wanted to share one thought on charging speed for Austin 4680. I would assume that Tesla has fairly conservative margins on allowable charging speeds, so they may have given some of that up to keep 4680 comparable for 2170. Also, an improved thermal management system may also compensate for that. Would be an interesting video if you were able to do a deep dive on thermal management for structural pack vs traditional pack. I'm sure there is a lot of evolution there discovered by Monroe teardown.

[@SolveFixBuild]

I don’t think Battery Day meant to imply all of the modifications would occur overnight. I didn’t expect DBE or tabless to happen as fast as it did. So if anything, Silicon might come faster than we (I) expected.

[@Mel_ilm]

Thank you for a very insightful video. I deeply appriciate your hard work.

[@thelimitingfactor]

Sure thing buddy 🤠

[@ky8187]

Great quality content as always. Hope you cross that 100gems in mark soon, well deserved

[@thelimitingfactor]

I hope so too! Looking forward to the little Play Button 😁

[@joeyang9475]

Thanks for sharing!

[@philforrence]

Great video! Will have to watch again!! So detailed!

[@michaelsmith2723]

Thanks, Jordan!

[@thelimitingfactor]

You're welcome buddy!

[@timhomstad]

Another great video as always

[@runeoveras3966]

Love it Jordan. Thank you. 😊

[@thelimitingfactor]

Glad to hear it man!

[@ewhite5291]

Thank you for the presentation from David Guay.

[@thelimitingfactor]

🤜🤛🤠

[@ps-gq5km]

God I love your intro, it’s so soothing

[@olegs79]

Great video. Thank you.

[@nahuelkondratzky7664]

great video!

[@mp3mike237]

Aren't you missing that the Model 3 battery is larger so 80% charging for it is more energy than 80% in the AWD Model Y. So while it got to 80% in the same time, it actually charged fewer kWhs, so it does charge slower.

[@bernhardleopold6702]

Charging speed of battery cells is not measured in kW but in %SOC/time unit.

[@w0ttheh3ll]

absolute charging power is irrelevant. If you charge two cars at the same time, you put more energy into the batteries (that you could view as a combined, bigger pack), without changing the actual batteries at all. for comparing battery tech, we are interested in charge rates. Jordan's comparison is the correct and useful one.

[@lifewalk244]

I think achieving the same energy density and same or better charging speed without using silicon is due to two things mainly: 1.) As you mentioned dry coating allows for better point to point contact and higher thickness of the anode --> Energy 2.) Tabless (multitab) design decreases the DCIR (Direct Current Internal Resistance). Low DCIR is one of the main drivers for charging speed and this effect somewhat counteracts the effect of slower Li-Ion uptake. But one has to say 30min is not that fast to be honest which is a issue of cylindrical cell form factor. Will be difficult to achieve same charging speed as with stack/winding based pouch or prismatic cells (just on a pure design point of view, but these form factors have other drawbacks). Nevertheless typically cylindrical cells have already usually between 7-10% Silicon. Prismatic cells maybe 4-6% One issue that we should not forget: Handling Si is not easy, you need to add other conductive agents, you have issues with swelling etc. Your voltage curve and nominal voltage changes (decreases). So also Tesla is new to the cell manufacturing game and might need to catch up to established cell suppliers like Panasonic, LG, Samsung or CATL. And maybe dry coating alone is a handful for now! I assume they will add it eventually but probably do not need to yet, due to the effects described above. Also Si cost maybe ~50-60 $/kg but graphite ~5-6$/kg

[@thelimitingfactor]

Totally missed this comment! Thanks man!

[@andrewbuck5016]

Why would Tesla make a storage optimized nickel cell instead of just using LFP? Seems like it would be a waste of nickel given the shortage of cleanly mined nickel.

[@thelimitingfactor]

Great question. This is something I wonder as well. I'm left with this view: -At this point it might be too premature to say whether a split chemistry pathway will be useful for Tesla's in house production. I included it in the video because I thought it was an idea worth putting out there. -Panasonic already uses a split chemistry pathway and has been for some time. The utility of that approach may outlive its usefulness, but at least in the interim, Tesla and Panasonic are finding it useful. -There will always be a mismatch between the number of cells required for a use case and the number available. The supply chain will constantly be evolving and Battery Tetris will be ongoing. So, a split chemistry pathway may not necessarily be a permanent fixture, but may prove to be useful intermittently to plug gaps in demand or to take advantage of short term slack where cell supply exceeds a specific need (both of which we've seen happen in the last few years). I could go deeper here with examples, but those are my general thoughts.

[@davidclark2286]

From some old Elon interviews my understanding was that domestic power walls used cylindrical cells containing nickel (& cobalt/manganese) to save weight. The power walls are delivered to site fully built with only electrical connections, settings and fixing of the unit carried out on site. These units are heavy and difficult for two men to handle in customer's homes. For the larger grid and commercial units they could buy lfp batteries on the open market. Mechanical handling is all done by machine. Most other manufacturers of power wall type products normally install the lfp batteries on site after the box has been installed thus avoiding handling weight problems/restrictions. TESLA have recently increased the size, capacity and weight of power walls, I suspect that this means batteries will have to be installed on site unless they have come up with home friendly handling equipment.

[@davidclark2286]

@@patreekotime4578 that is unlikely but we will have to wait and see the performance of the batteries when they are available. Claims made at the moment are extremely erratic. My impression is that per kWh they weigh more and the cycle life while better than lead acid is far worse than lithium iron at between 800 to 1000 discharge cycles. This would suggest they are not going to be suitable for ststionary storage. I read of a CATL plan to lease them, each vehicle having 3 'batteries' but only needing one of them to run. So one could have the long term lease for one battery and rent an extra battery or two for longer trips. This would make battery swap set ups interesting.

[@rcinfla9017]

Thicker electrode means higher AH capacity for given size and weight, but limits maximum cell current, earlier onset of electrode layer ion starvation, and greater internal heat generation for high current. Greater internal heating and larger 4680 cell size may make thermal management more challenging.

[@rcinfla9017]

There is a practical limit to increasing anode capacity in terms of limit to how thin the anode layer can be made relative to the corresponding cathode thickness capacity. Thickening up cathode layer to ratio match a higher capacity thin limit anode layer is not an option as it degrades performance of cathode.

[@xsirfr1958]

Hey Jordan - what’s your take on Stordot? Do they really have the goods?

[@thelimitingfactor]

I don't know why people are focused on them. They are 1/100 companies making similar claims. How often do these companies make it big? None as far as I can tell.

[@AfaqSaleemChannel]

I will take a guess here after learning from your video. Tesla has Cybertruck and Semi coming up, both relying on 4680, both would be desired to have long cycle life due to commercial nature and not KW constrainted bcz of large packs KWh they would need to meet range requirements, so Tesla might be focusing on perfecting carbon Anode which complements vehicle requirements and existing chemistry before moving to silicon for vehicles like Roadster, S & X.

[@DavidMG99]

👍👍

[@brettmciver432]

Can you mix sulphur in to the mix with silicon? Or is there an arguement between the 2 elements?

[@toddpossum]

Farzad sent me

[@thelimitingfactor]

🤠🙌

[@saurabhchandra6267]

Silicon is that overrated wow. Amazing content. Hope you receive munro battery soon.

[@lifewalk244]

Not overrated. But very tough to handle

[@fgabrieltomas]

My name is Taylor and i approve this video 🤣

[@thelimitingfactor]

🤣🤣🤣

[@JoelSapp]

Nice homage to Where's the beef ? 😅

[@weaverdreams]

So where is the silicon?

[@Kjgunn1111]

Hi Jordon - didn't Elon say that his priority this year was to complete the design of the Robotaxi? Couldn't these silicon-free cells be the best choice for a long-service life taxi - and the reason why this design has been chosen?

[@thelimitingfactor]

I think they'll use CATL or BYD LFP for that vehicle 😀

[@utube091116]

XXLnt !

[@hallkbrdz]

Since most of my vehicles have more than 200k miles, I'd really like longer life for a future EV.

[@thelimitingfactor]

Elon has said 3-500k miles. I'm being conservative until it shows in the data. So as not to screw people over with high expectations.

[@user-wy4mp9ts3u]

Graphene is getting cheaper and very light relative to its effectiveness and light generally.There are quite a few types of graphite also so with the right formula it is possible.Silicon has many problems.

[@joeyang9475]

Does anybody know the spec of anode TESLA 4680 is using? Any information about the formulations of anode electrodes? Thanks!

[@justinw1765]

Uh oh... We're moving towards the Matrix since y'all are being categorized according to your energy density...

[@nealtauss1715]

... the best silicon is no silicon and.... the best graphene comes from hemp.....

[@avikaragrawaal2824]

Thanks!

[@thelimitingfactor]

You're Most Welcome!

[@kennethhickey6068]

Thanks!

[@thelimitingfactor]

Sure thing Kenneth! Thanks for the support.