基于仿真对比的电池等效电路模型分析

摘要

Lithium iron phosphate battery (LiFePO4) has become the research focus in electric vehicle application areas,due to its high specific power,high specific energy,long life and other advantages.A reasonable equivalent model is necessary for accurate state-of-charge (SOC) estimation.The battery SOC estimation is affected by accuracy and complexity of the model directly.This paper analyzed four equivalent circuit model parameters,and the hybrid pulse power characterization (HPPC) is executed based on LiFePO4 battery test system.The least squares method was implemented in model parameterization,and voltage estimation accuracy of the three empirical models with RC network structure was compared in SOC range 0 ～ 100％.Dual polarization equivalent circuit model accuracy was compared at different temperatures based on federal urban driving schedule (FUDS) test.The experimental results show that dual polarization equivalent circuit model provides better accuracy and low-temperature characteristics.%磷酸铁锂电池(LiFePO4)凭借其较高的比功率、较高的比能量和使用寿命长等优点,逐渐成为电动汽车领域应用电池的研究热点.准确的电池荷电状态(State-of-Charge,简称SOC)估计离不开合理的等效模型,模型的精度与复杂程度直接影响电池SOC估计.文章首先分析四种等效电路模型参数,基于电池测试系统对LiFePO4进行混合脉冲功率性能测试(The Hybrid Pulse Power Characterization,简称HPPC),应用最小二乘法进行模型参数辨识,根据辨识结果对比模型精度与复杂程度;然后将电池在整个SOC周期内对三个带有RC网络结构的模型精度进行对比;最后对LiFePO4电池进行联邦城市运行工况(The Federal Urban Driving Schedule,简称FUDS)测试,对比双极化等效电路模型在不同温度下模型精度.实验结果显示双极化等效电路模型为具有良好精度的等效电路模型,同时带有低温特性.