低温环境下车用锂电池预加热策略研究

To improve the driving range of electric vehicles under low temperatures, a battery pack heating strategy based on the optimization of heating target temperature is proposed in this paper, which can effectively enhance the battery energy efficiency to achieve the driving requirement under low temperature. Firstly, the maximum discharge capacity of the battery at different temperatures is determined by the experiment test. Secondly, based on the energy retention rate of the battery at different temperatures and considering the influence of temperature on the battery life, a nonlinear multi-objective constraint function is established and solved to obtain the optimal heating target temperature of the battery under different ambient temperatures and different SOC. Finally, the heating strategy is validated via simulation of the physical model calibrated with real world vehicle experiment data. The experimental results show that the vehicle driving range based on the optimized battery heating target temperature increases maximumly by 8.41% and 4.77% respectively at the initial temperature of -15 and -5 ℃, indicating the proposed method can effectively improve the driving range of electric vehicles at low temperature.