Analysis on the influence of measurement error on state of charge estimation of LiFePO4 power Battery

The error sources of state of charge(SOC) estimation of li-ion battery based on Kalman filter is analyzed in this paper. To LiFePO4 power battery, the extremely flat part during the normal SOC range of SOC-OCV curve will require strong restriction to the voltage detection especially. This paper aims at the influence of the measuring precision of the voltage and current signal of battery management system (BMS) to SOC estimation of the li-ion battery including LiFePO4 battery. A simulation analysis is performed independently in Simulink on the assumption that other factors are under ideal conditions, in which the effects of Gaussian white noise and offset error of measurement of BMS are discussed respectively to simulate the actual vehicle condition. The principle to the precision index design of BMS is proposed according to the analysis result, in addition, a high-precision data acquisition system is developed as a precise calibration benchmark device for BMS.