Detection Method of Lithium Plating of Lithium-Ion Battery Based on Complex Morlet Wavelet Transform

Lithium-ion batteries (LIBs) are widely used in electric vehicles (EVs) and energy storage systems for their high energy density, high power density and long service life. The phenomenon of lithium plating (LP) has always threatened the safe operation of LIBs, and the detection of LP by electrochemical impedance spectroscopy (EIS) has become the focus of industry and academia. Therefore, in order to solve the time-consuming problem of existing LP detection method, this paper proposes a method of EIS calculation and LP detection method based on complex Morlet wavelet transform (CMWT). Firstly, the boundary conditions of LP phenomenon in LIBs under different rates and ambient temperatures were investigated through LP induction experiments. Then, the EIS of the battery was extracted quickly by current excitation pulse and CMWT. Finally, the EIS variation rules in different SOC intervals after LP are studied, and the LP criterion is formed. The LP detection method in this paper can promote the reduction of EIS detection time.