纯电动汽车用磷酸铁锂电池工作特性分析与表征

Analysis of Working Characteristics and Characterization of Iron Phosphate Lithium Battery for Pure Electric Vehicle

磷酸铁锂电池作为锂离子电池之一,因原材料磷、铁存在于地球的资源含量丰富,并且在高温与高热环境下的稳定性高等优势,在纯电动汽车中有着广泛的应用。为准确估算磷酸铁锂电池的荷电状态(SOC),以容量为10Ah的磷酸铁锂电池作为对象进行了研究,控制温度在25℃下,通过标准充电与放电试验、不同倍率的充放电试验和OCV-SOC非线性曲线辨识试验分析其工作特性。根据电池内部的极化反应、OCV-SOC相对稳定性,建立戴维南等效模型。通过HPPC测试试验对其实现参数辨识,得出欧姆内阻均值R0为20.68mΩ,极化内阻均值RP为1.36mΩ,极化电容均值CP为47747.9F。通过试验得到其电压、电阻工作特性,且模型参数可为锂离子电池的荷电状态准确估算提供理论依据,为纯电动汽车用磷酸铁锂电池今后建模仿真、SOC的准确估算和电池管理系统设计提供了可行性方案。

As one of the lithium ion batteries,iron phosphate lithium battery is widely used in pure electric vehicles due to the abundant resources of raw materials phosphorus and iron in the earth and its high stability in high temperature and high heat environment.In order to accurately estimate the state of charge (SOC) of lithium iron phosphate battery,a lithium iron phosphate battery with a capacity of 10 Ah is studied;and its working characteristics are analyzed through standard charging and discharging experiments,charging and discharging experiments with different rates and OCV-SOC nonlinear curve identification experiments at 25 degrees Celsius.According to the polarization reaction inside the battery and the relatively stable OCV-SOC,the Thevenin equivalent model is established.Through HPPC test for parameter identification of its implementation and the conclusion ohm resistance mean value R 0 of 20.68 mΩ,polarization resistance mean R P of 1.36 mΩ,polarization capacitance mean C P of 47 747.9 F .The working characteristics of voltage and resistance are obtained through experiments,and the model parameters can provide a theoretical basis for the accurate estimation of the SOC of lithium ion batteries.It provides a feasibility scheme for the modeling simulation,battery management system design and practical application of lithium iron phosphate battery for pure electric vehicle.