Abstract:

For the problem of SOC estimation accuracy reducing that is caused by the lithiumion battery capacity losing in pure electric vehicle, the paper analyzes the influence factors of battery capacity losing and put forward a capacity correction algorithm. By improving battery model, the battery capacity is as state variables and the capacity correction algorithm is used in kalman filter to estimate the SOC. This solves the error accumulation problem that is caused by the lithiumion battery capacity losing. The test proves that the based on the capacity fixed kalman optimal filter algorithm is of benefit to improving the accuracy of SOC estimation and performs well when initial error happens. The method can ensure the stability of lithiumion of pure electric vehicle.

Key words: pure electric vehicle;battery capacity losing;SOC estimation;Kalman filter algorithm