锂电池电化学阻抗谱的多项式等效电路模型

Polynomial equivalent circuit model for electrochemical impedance spectroscopy of lithium ion battery

选取磷酸铁锂圆柱形锂离子电池为实验对象,测试其在263、273和283 K低温环境,298 K常温环境和不同荷电状态(SOC)值下的电化学阻抗谱,建立锂电池多项式等效电路模型,对比了传统等效电路和多项式等效电路的拟合性能,结果表明多项式等效电路模型具有良好的性能,八阶多项式函数足以描述SOC对电路参数的非线性影响,为预测不可见SOC的阻抗谱和电路参数奠定了基础。

Lithium iron phosphate cylindrical lithium battery was selected as the test object.The electrochemical impedance spectra of different SOC values at low temperature environment of 263,273 and 283 K and normal temperature environment of 298 K was tested,and the polynomial equivalent circuit model of lithium battery was established.The fitting performance comparison result of the traditional equivalent circuit and the polynomial equivalent circuit shows that the proposed polynomial model is effective,the eighth-order polynomial function is sufficient to describe the nonlinear influence of the SOC on the circuit parameters,and it lays the foundation for predicting the impedance spectrum and circuit parameters of the invisible SOC.