QuantumScape, San Jose, California, is pleased to inform that the cells the company showed at the Battery Showcase (12/8/2020) continue to cycle and have now exceeded 1,000 cycles (over 1,100). This corresponds to over 300,000 miles for a 300-mile battery pack and over 500,000 miles for a 500-mile battery pack.
At cycle 1000, energy remaining in the cells is 87.5-91.8%, with a median of 90.5% at 1C. The capacity retention of these cells gives a Coulombic efficiency (CE) of > 99.991%. Note that to get to 800 cycles, a CE of 99.972% is required, and a CE of 99.955% only gets to 500 cycles.
These are single-layer cells:
-full depth-of-discharge cycles (0-100% SOC)
-30°C (not > 60°C)
-1C/1C rate (not ≤ C/3)
-Thick cathode (3.2mAh/cm2)
-High current density (3.2mA/cm2)
-Commercial-target area (70x85mm)
-Zero lithium anode as manufactured
-~3.4atm of pressure (not>10atm).
Battery researchers know the hardest part of making solid-state lithium-metal batteries work is hitting all these conditions simultaneously – compromising on even one (e.g., current density or temperature or pressure or cycle life) makes the cells not commercially relevant.
This updated cycle life slide can be found as part of the updated Battery Showcase presentation here – Battery Showcase