On advanced state-of-health assessment for lithium-ion batteries of degradation mode identification with time-domain AC impedance analysis
摘要
Accurate estimation of the state of health (SOH) of lithium-ion batteries (LIBs) is essential for the safety of energy storage devices. Electrochemical impedance spectroscopy (EIS), which measures kinetic information in LIBs, is a powerful tool for explaining the degradation mechanisms of these batteries. To understand the internal state of coupled-measured LIBs, the distribution of relaxation times (DRT) method was first employed to reconstruct the EIS data and extract valuable health factors (HFs). Next, correlation analysis was used to identify the most pertinent degradation mode of LIBs at different states of charge (SOCs) and temperatures. Finally, four training test cases were designed using recurrent neural network to estimate SOH on LiCoO2 battery datasets at 25 °C, 35 °C, and 45 °C. The model demonstrated a root mean square error (RMSE) of 0.67% and a mean absolute error (MAE) of 0.41%, while also exhibiting greater robustness and requiring less training time. This work demonstrates the excellent performance of time-domain information from AC impedance, offering a promising solution for battery SOH estimation.