Estimation of State of Charge for Lithium-ion Battery Considering Effect of Aging and Temperature

Accurate estimation of state of charge (SOC) is necessary for battery management system in electric vehicles. In this paper, a dual polarization temperature-dependent battery model of Lithium-ion battery is built considering the aging effect. The relationships between temperature and model parameters are obtained by battery calibration experiments. The model accuracy is verified under different temperatures. Then the multi-scale extended Kalman filter (MEKF) is chosen to estimate SOC and battery capacity with different time scales, which can address the different variation rates between SOC and battery capacity. Finally the MEKF estimator is tested in Matlab under variable temperatures and the simulation results show that the proposed model and method have high accuracy.