Effects of Fast Charging Modes on Thermal Performance of Lithium-Ion Battery

Fast charging technology can greatly increase the charging speed and shorten the charging time of electric vehicles, but the heat generation and temperature rise of the lithium-ion battery during the fast charging process seriously affect its electrochemical characteristics and cycle life and even cause safety issues. Therefore, it is necessary to analyze the thermal performance of the lithium-ion battery under fast charging conditions and investigate the effects of different fast charging modes on it. Herein, an NMC lithium-ion cell is taken as the object, and the electrochemical-thermal coupling model is built and verified. Based on this model, the heat generations and temperature rises of the cell in different fast charging modes are analyzed and compared, including constant current (CC) charging, constant voltage (CV) charging, CC-CV charging, stage CC charging, and pulse charging. It is found that the peak temperature of the cell appears at different moments in the above charging modes. The peak temperature and total heat generation during CV charging are much greater than those during charging of other modes. The results can provide references for the design and selection of charging modes and battery thermal management systems toward fast charging technology.