Abstract:At present, the decommissioned power batteries have problems of low screening efficiency, high energy consumption and low grouping rate. To address these issues, a fast screening and recombinant method is proposed, which is based on short-time pulse discharge and electrochemical impedance spectroscopy ( EIS ) for decommissioned power batteries. Through the short-time pulse discharge, EIS test and analysis of 200 decommissioned lithium iron phosphate power batteries of the same type and different batches, the obtained pulse voltage difference, DC internal resistance, EIS curve shape characteristics and EIS equivalent circuit model parameters are taken as screening indicators. Then, a mathematical model is formulated to realize the rapid and effective sorting and reorganization of decommissioned power batteries. Experimental results show that this method can effectively reduce energy consumption. The average test time of a single cell is less than 20 min. Meanwhile, the module consistency index after grouping is good, which has great practical value in engineering.