Polarization is the main factor affecting the fast charging efficiency of lithium-ion batteries. In this paper, based on the traditional RC circuit model simulation of lithium-ion battery charging process, the charging current, the initial SOC, the initial polarization state, the cycle of life and other aspects of the analysis, the establishment of the polarization voltage and SOC relationship model, it can be estimated Polarization voltage of lithium-ion battery. On the basis of this study, the fuzzy control algorithm is used to control the charging polarization voltage to optimize the fast charging of the battery, so that the charging current can adapt to the SOC rechargeable current of the lithium-ion battery at any time. The experimental results show that the proposed method can greatly shorten the charging time by about 20% compared with the traditional constant current constant voltage method, and improve the charging efficiency, and there is no obvious temperature rise.