QuantumScape Corporation, a developer of next-generation solid-state lithium-metal batteries for use in electric vehicles, released an independent third-party laboratory testing report on the performance of its solid-state lithium-metal battery cells.

QuantumScape’s single-layer cells were tested by Mobile Power Solutions, an independent battery lab, and met automotive-relevant conditions: more than 800 cycles at 25 °C, 1C (one hour) charge/discharge rates, 100% depth of discharge and under 3.4 atmospheres of pressure.

The company said that it believes that the results from the tests, covering a group of three single-layer cells, are consistent with those initially reported by QuantumScape in December 2020. (Earlier post.)

We are happy that these independent test results substantially replicate the cycling performance we reported at our December 2020 Battery Showcase. With the publication of this report, we will continue to focus on our product roadmap goals and delivering cells to our customers.

—Jagdeep Singh, CEO and co-founder of QuantumScape

The test performed on QuantumScape’s cells reflects a complete cycle-life test that demonstrates how well the cell chemistry performs under extended high-performance usage and various commercially relevant conditions for EVs. These conditions, which QuantumScape believes must be met simultaneously, include:

• 800 cycles — roughly equivalent to 240,000 miles driven for a 300-mile range vehicle and demonstrating the battery technology’s ability to perform over a vehicle’s expected lifetime

• 25 °C — operating at room temperature, as opposed to elevated temperatures (e.g., 60-80 °C), showing the robustness of a battery’s power capability

• 1C charge/discharge rates — indicate that the battery can operate at continuously high charge and discharge rates with minimal degradation (with energy retention maintained at more than 80%) over a long period (800 cycles in this case)

• 100% depth of discharge — the battery was fully charged and discharged every cycle of testing, which is typically more strenuous on the battery than shallower charge and discharge cycles

• 3.4 atmospheres of pressure — this amount of pressure is sufficiently low for automotive applications

Mobile Power Solutions is an independent battery laboratory, ANAB accredited to ISO/IEC 17025:2017, based in Beaverton, Oregon.