Research on Modeling and Characteristic Parameters Consistency of Retired Lithium Power Batteries

Abstract

Abstract For retired power batteries, it is difficult for single cell to meet the power requirements, and there is a problem of poor consistency between multiples. Therefore, re-grouping and consistency assessment are required for cascade utilizaton of retired batteries. In this paper, the remaining capacity test and HPPC test of retired lithium power batteries were carried out. And then the consistency of characteristic parameters of retired batteries under different SOC conditions was compared and analyzed based on capacity, internal resistance and other parameters. The results show that as the battery discharges, the ohmic internal resistance increases, and the consistency of polarization resistance and polarization capacitance are obviously deteriorated. Therefore, it is more reasonable to group them into consistent groups according to the electrochemical parameters of retired batteries at high discharge depth. Moreover, there is no strong correlation among the characteristic parameters such as open-circuit voltage, internal resistance and capacitance. Multiple parameters are required to evaluate the consistency of retired lithium batteries.