Prepared for: Amprius
Test report numbers: AK-1823
Prepared by: Spencer Poff, Engineering Manager
Report date: 3/17/2023

Executive Summary

Amprius Technologies Model RD1039-R49 cells were tested at MPS using a test regimen provided by Amprius. The results indicate that this cell model provides >504 Wh/kg and >1321 Wh/l at 25°C.




The cells arrived in a well cushioned box placed in a steel drum.

Incoming inspection

  • Cells/compression fixtures were visually inspected. No visible damage or other anomalies were observed.
  • Voltage was recorded.
  • 1kHz impedance was recorded.


The cell tabs were trimmed to the proper length needed for testing.
All charge and discharge tests were conducted at 25°C ±1°C.

Test Protocol conducted:

  • Constant Current Charge at C/10 (660mA) to 4.37V, then Constant Voltage charge (taper) at 4.37V to a cutoff current of C/100 (66mA).
  • Rest for 15 minutes.
  • Constant Current Discharge at C/10 to 2.4V.
  • Rest for 15 minutes.
  • Repeat for a second cycle.
  • Charge the cells to 30% SOC before removing fixture and measuring the cells.



The fixtures were removed from the cells.
Cell mass was recorded. Width and length of the body of the cell were measured with calipers on the main body of the cell not including the tab terrace or seams. Thickness was measured by parallel plate gage using 600g mass.


Test Results: