[cyberax]

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!

[vel0city]

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.

[onethought]

I’m not sure id call Chevy widely sold, yet. Their full year sales don’t even match a single quarter of Tesla.

[ggreer]

Also GM had to replace batteries in 142,000 Chevy Bolts & Volts due to fire risk, so I'm not sure that should count as an example of a successful use of non-cylindrical, non-LFP batteries.

[rasz]

To be fair everyone had to recall those LG batteries and unauthorized SK clones [*]. Porsche Taycan, Ford F-150, its recalls all the way down.

https://www.wardsauto.com/news/ford-terminates-ev-battery-su...

https://www.autoevolution.com/news/ford-recalls-f-150-lightn...

SK settled for $2B case that revealed they stole LG battery technology https://cleantechnica.com/2021/02/15/itc-sides-with-lg-chem-...

[vel0city]

I can go to any major metro area in the US and go buy a GM EV today. That's widely sold.

[onethought]

That’s “widely available” — no one is buying them, so not “widely sold”

[rent0pat]

How are circles optimal???

Circle packing = 90%

Blade battery packing = 100%

[epgui]

it's not just a basic geometry problem, it's an engineering problem. You need to account for far more details.

[cyberax]

It's more complicated. You can't pack the battery at 100% anyway, because you need cooling. Cylindrical cells are also more rigid, so they need less supporting material, or they can even be a part of the support structure itself.

[moogly]

With cylindrical cells, you have more leeway in the overall shape of the battery pack and can fill nooks and crannies with them.