基于AMESim的车用磷酸铁锂动力电池包寿命仿真分析

Life prediction of vehicle lithium-iron phosphate battery based on AMESim

利用AMESim软件建立了一维电化学-热耦合模型,对车用磷酸铁锂动力电池包的质保寿命进行预测。通过研究15 Ah磷酸铁锂电芯的混合动力脉冲能力特性数据和老化数据,获得了模型所需的电芯内阻、开路电压及容量衰减等相关电化学参数;通过研究动力电池包在不同运行工况下的温度变化趋势,标定出模型所需的热特性参数;通过对比动力电池包的实测循环实验数据与仿真结果,验证了电化学-热耦合模型的精度并得出了容量衰减预测值与实测值的误差仅为0.3%;在此仿真模型基础上,以CLTC-P工况模拟车辆行驶,预测出该动力电池包在合肥地区运行8年20万公里时的容量衰减率为17.4%,且证实了电池包内部温度差过大带来内阻的增加,加剧容量衰减。

This study employed AMESim software to build a one-dimensional electrochemicalthermal coupling model for predicting the lifetime of the lithium iron phosphate(LFP)battery pack.The electrochemical parameters(i.e.,cell internal resistance,open circuit voltage,and capacity attenuation)of the model were obtained by analyzing the hybrid pulsed power characterization and the aging data of 15 Ah LFP battery.The temperature change trend of the pack under various operating situations was examined to calibrate the thermal parameters.The accuracy of this model was further verified by comparing the simulation data with the experimental data.The discrepancy between simulated values and experimental values of capacity attenuation was only 0.3%.Utilizing this highprecision simulation model,the lifetime of battery pack was evaluated under the CLTC-P condition,and the capacity attenuation rate of the battery pack was 17.4%when it ran for 8 years and 200000 kilometers in Hefei city.Consequently,an excessive temperature difference inside the battery pack increases the cell resistance and aggravates the capacity attenuation of the battery pack.