Comparative Study on Traction Battery Charging Strategies from the Perspective of Material Structure

The service life of an electric vehicle is, to some extent, determined by the life of the traction battery. A good charging strategy has an important impact on improving the cycle life of the lithium-ion battery. Here, this paper presents a comparative study on the cycle life and material structure stability of lithium-ion batteries, based on typical charging strategies currently applied in the market, such as constant current charging, constant current and constant voltage charging, multi-stage constant current charging, variable current intermittent charging, and pulse charging. Compared with the reference charging strategy, the charging capacity of multi-stage constant current charging reaches 88%. Moreover, the charging time is reduced by 69%, and the capacity retention rate after 500 cycles is 93.3%. Through CT, XRD, SEM, and Raman spectroscopy analysis, it is confirmed that the smaller the damage caused by this charging strategy to the overall structure of the battery and the layered structure and particle size of the positive electrode material, the higher the capacity retention rate is. This work facilitates the development of a better charging strategy for a lithium-ion battery from the perspective of material structure.