Comment by fencepost
21 hours ago
Doing a quick bit of searching based on the 4680 makes me think that there has been or will be a change from NMC811 to LFP chemistry in the 4680, including one article talking about changing to US and European-based in-house manufacturing and reducing dependence on China.
I'm no fan of Tesla, but this looks like the collapse of the contract with the supplier for the battery chemistry they've moved away from, aka "no [more] big deal."
2023 article confirming NMC chemistry: https://iopscience.iop.org/article/10.1149/1945-7111/ad14d0
5/2025 article discussing change to LFP: https://roboticsbiz.com/teslas-4680-lfp-battery-explained-ch...
3/2025 article comparing BYD's LFP and Tesla's NMC/NCM: https://www.sciencedirect.com/science/article/pii/S266638642...
Does having larger LFP cells, like the 4680 format, allow this chemistry to be used in higher-performance models? Right now it looks like only the RWD basic models use LFP cells everything else uses NMC.
This makes sense but does it make sense to manufacture LFPs as 4680 cylinders instead of rectangular blocks/blades, given https://en.wikipedia.org/wiki/BYD_Blade_battery ?
Which cell technology to use depends on the application. Tesla actually uses BYD blade batteries in some of their vehicles sold in Europe. The main issue with prismatic cells is that to be safe, they must be made with LFP chemistry, which hurts energy density. LFP is also worse at charging/discharging when cold, though battery management software mostly solves that.
Cylindrical cells make sense for higher performance NMC and NCA chemistries, as they can be cooled more easily (coolant lines can run in the voids between cylindrical cells), and any single cell failure is less likely to cascade to other cells. Batteries with cylindrical cells were easier to repair, but nowadays cells are welded together instead of bolted, so that's no longer an advantage.
> The main issue with prismatic cells is that to be safe, they must be made with LFP chemistry, which hurts energy density
This is obviously untrue. Tons of other chemistries have used prismatic cells with good safety as well. You think Macbooks and iPhones use LFP or cylinder cells?
> Batteries with cylindrical cells were easier to repair,
It can be just as easy to repair a prismatic battery as a cylinder battery. It all comes down to the layout of the battery. And as you mentioned, how the battery is constructed, if the battery is structural, etc.
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Yep. Prismatic cells have poorer packaging-to-material ratio (circles are optimal). They offer better thermal properties, but thermals are not the main limiting factor anymore.
And the US automakers tried prismatic cells before. Chevy Volt used them in 2012!
How are circles optimal???
Circle packing = 90%
Blade battery packing = 100%
Chevy sells EVs with prismatic and pouch cells. I don't recall any they've widely sold that used cylinder cells. Most automakers use prismatic cells on their cars, even non-LFP variants.
Yeah, it's typical of Elektrec to interpret anything Tesla-related in the worst light.
I personally fact checked articles about "Autopilot disengages milliseconds before collision" and the one related to Benavides v. Tesla case.
In the first case they jumped to conclusions. In the second case they "forgot" to mention any details that contradict their narrative: that there were two cases separated by years, that the police has received all the information they needed in the first case, that the driver was pressing the accelerator.
My understanding is Fred (Electrek) has been nothing but negative about Tesla since he got upset that they haven't released the roadster yet. Something to do with having enough referral points to get one. It has become his whole identity and it is sad to see.