Investigation into State-of-Health Impedance Diagnostic for 26650 4P1S Battery Packs

State-of-Health (SoH) is a critical parameter for determining the safe operating area of a battery cell and battery packs to avoid abuse and prevent failure and accidents. Experiments were performed at the US Naval Research Laboratory (NRL) on a 4P1S cell array using pulsed discharge and electrochemical impedance spectra (EIS) to determine a single-point SoH frequency for the array as a whole. Individual cell EIS measurements were taken, as well as measurements of the array as a whole. This work will discuss experimental results to date.