Sensitivity of Electrochemical Impedance Parameters for Detecting Changes in Lithium-Ion Batteries due to Acceleration Shocks and Local Mechanical Deformations

Electrochemical Impedance Spectroscopy (EIS) offers valuable insights into cell characteristics and presents a promising tool for enhancing battery management systems (BMS) in electric vehicles (EVs). Its potential to detect safety-critical conditions, such as acceleration shocks and local mechanical deformations, along with its sensitivity to State of Charge (SOC), State of Health (SOH), and preload, remains underexplored. This study addresses this gap by performing EIS measurements on commercial lithium-ion pouch cells, assessing the impact of acceleration shocks and local mechanical deformations while considering its sensitivity to capacity levels, mechanical surface loads, and aging histories. A sensitivity analysis identifies the most responsive EIS parameters and frequencies for detecting cell changes induced by acceleration shocks and local mechanical deformations, independent of capacity levels, mechanical surface loads, and aging histories. Results show the real part of the impedance (Re) at 97.66 Hz and 976.56 Hz is highly sensitive to acceleration shocks. For local mechanical deformations, the magnitude of impedance |Z|, Re, and the minimum phase angle exhibited high sensitivities at frequencies between 1.09 Hz and 976.56 Hz. These findings highlight EIS’s potential to detect safety-critical changes in lithium-ion batteries (LIBs), supporting their use in BMS for safety monitoring in commercial EV applications.