Rapid prediction of the state of charge and health of retired power batteries based on electrochemical impedance spectroscopy

Aiming at the problems of long time, low accuracy and high energy consumption in detecting the health status of retired power batteries at this stage, a rapid prediction method of battery state of charge (SOC) and state of health (SOH) based on electrochemical impedance spectroscopy (EIS) is proposed. First, through electrochemical impedance spectroscopy measurements of multiple retired power batteries with different SOHs at different SOCs and different temperatures, the relationship between impedance amplitude, phase angle and the equivalent circuit model parameters obtained by fitting and SOC at different temperatures are analyzed. Then, based on this, find the most stable impedance parameter to establish the battery SOC estimation algorithm to realize the rapid estimation of the SOC of the retired power battery;Finally, the EIS twice measurement method is proposed to quickly predict the state of charge and health of the retired power battery, and the minimum error of the verification experimental results is less than 1%. Using this method can greatly reduce test time, save energy, and achieve rapid estimation of unknown state of charge and health of the battery.