采用Morlet小波的锂电池相对健康状态估计

A novel estimation method based on Morlet wavelet for the relative state-of-health (SOH) of lithium-ion batteries is proposed to solve the problem that the existing methods of estimating battery SOH have low estimation accuracy and large computation. Firstly, the correspondence between electrochemical impedance spectroscopy (EIS) and SOH is explored. Then, the data of voltage and current of a battery are obtained under actual working condition, and the Morlet wavelet is used to perform wavelet transform on the data. The EIS of the battery is estimated online by calculating the wavelet coefficient ratio of voltage signal to current signal. Finally, the SOH of the battery is predicted by the online estimated EIS. The proposed method has the advantages of no need for a lot of experimental data, high accuracy and high computational efficiency. Urban dynamometer driving schedule (UDDS) tests are conducted, and results show that the proposed method accurately estimates the relative SOH of the battery, and the estimation error is less than 3.3%.