4 ms·

Yep. Prismatic cells have poorer packaging-to-material ratio (circles are optimal). They offer better thermal properties, but thermals are not the main limiting

by cyberax 10mo ago

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 10mo ago
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 10mo ago
  I’m not sure id call Chevy widely sold, yet. Their full year sales don’t even match a single quarter of Tesla.
  - vel0city 10mo ago
    I can go to any major metro area in the US and go buy a GM EV today. That's widely sold.
    - onethought 10mo ago
      That’s “widely available” — no one is buying them, so not “widely sold”
  - ggreer 10mo ago
    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 10mo ago
      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-supply-deal-lg-energy-solution/808340/ https://www.wardsauto.com/news/ford-terminates-ev-battery-su... https://www.autoevolution.com/news/ford-recalls-f-150-lightning-over-potential-battery-cell-manufacturing-defect-248161.html 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-in-sk-innovation-patent-infringement-case/ https://cleantechnica.com/2021/02/15/itc-sides-with-lg-chem-...
rent0pat 10mo ago
How are circles optimal??? Circle packing = 90% Blade battery packing = 100%
- epgui 10mo ago
  it's not just a basic geometry problem, it's an engineering problem. You need to account for far more details.
- moogly 10mo ago
  With cylindrical cells, you have more leeway in the overall shape of the battery pack and can fill nooks and crannies with them.
- cyberax 10mo ago
  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.

by cyberax 10mo ago

vel0city 10mo ago

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 10mo ago
I’m not sure id call Chevy widely sold, yet. Their full year sales don’t even match a single quarter of Tesla.
- vel0city 10mo ago
  I can go to any major metro area in the US and go buy a GM EV today. That's widely sold.
  - onethought 10mo ago
    That’s “widely available” — no one is buying them, so not “widely sold”
- ggreer 10mo ago
  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 10mo ago
    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-supply-deal-lg-energy-solution/808340/ https://www.wardsauto.com/news/ford-terminates-ev-battery-su... https://www.autoevolution.com/news/ford-recalls-f-150-lightning-over-potential-battery-cell-manufacturing-defect-248161.html 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-in-sk-innovation-patent-infringement-case/ https://cleantechnica.com/2021/02/15/itc-sides-with-lg-chem-...

rent0pat 10mo ago

How are circles optimal??? Circle packing = 90% Blade battery packing = 100%

epgui 10mo ago
it's not just a basic geometry problem, it's an engineering problem. You need to account for far more details.
moogly 10mo ago
With cylindrical cells, you have more leeway in the overall shape of the battery pack and can fill nooks and crannies with them.
cyberax 10mo ago
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.