关键词: 退役锂电池；SOC 估计；最大可用容量；双扩展卡尔曼滤波

Abstract: In order to improve the safety of retired lithium-ion batteries of electric vehicles in cascade utilization, it is necessary to obtain the state of charge (SOC) parameter values of retired batteries in use accurately and timely. Because the aging of retired batteries will cause capacity decay faster and seriously affect the estimation accuracy of SOC parameters, this paper proposes an online SOC estimation method considering the capacity decay of retired lithium-ion batteries. Through the test of hybrid plulse power characteristic (HPPC) and dymanic stress test (DST) cycle conditions, it is proved that the proposed method can estimate the SOC of retired lithium-ion batteries under different operating conditions accurately and realtimely, and the maximum estimation error is less than 2%.

Key words: Retired lithium-ion batteries; SOC estimation; Maximum usable capacity; Dual extended kalman filter