An update on QuantumScape's cycle life

Original post at Twitter here

An appreciated update from QuantumScape on encouraging cycle life tests, although there is not much new info since the showcase. But I am reminded a little bit about Jeff Dahn’s “million mile battery” from ~15 months back…

A lot of people seemed to read that paper as an indication of what Tesla would soon be able to do (maybe?) - I read it more as an encouraging sign of what the Li-ion chemistry was capable of in terms of cycle life, and that’s how I look at this too.

What also made me think of the Dahn paper was the mention of 99.991% charge efficiency - Dahn’s paper reported CE as high as 99.985% for optimised electrolytes. Though I’m cautious about this comparison since CE ≠ capacity loss per cycle.

Some things I’d hope to see in future data releases:

  • At least a bi-layer cell, preferably more layers
  • Some indication of separator thickness to get a better idea of achievable energy density
  • How much catholyte…
  • Calendar life at 100% SoC
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