基于三阶RC网络的等效电路电池模型

Equivalent circuit model for battery based on third-order RC network

针对Thevenin模型结构过于简化、精度不足的问题,提出一种精确的三阶RC网络等效电路模型。在充分考虑电池极化的基础上,对磷酸铁锂正极锂离子电池进行充放电性能测试,并用最小二乘拟合法对模型参数进行辨别。基于Simscape搭建Thevenin模型及三阶RC模型,用变电压对模型进行仿真分析。三阶RC网络电池模型估算的相对误差不超过±0. 01 V,相比于Thevenin模型的±0. 06 V,精度更高,更能体现电池的特性。

Aiming at the problems of simplified Thevenin model structure and insufficient accuracy, a kind of accurate third-order RC network equivalent circuit model was proposed. The experimental data was obtained through charging and discharging performance of lithium iron phosphate ( LiFePO4 ) cathode Li-ion battery, the model parameters were identified by the least squares fitting method on the basis of fully considering the polarization of the battery. The Thevenin model and the third-order RC mode) were built based on Simscape model library, which the simulation analysis was carried out on the model with the variable voltages. Compared with Thevenin model(±0. 06 V),the average error estimated by the third-order RC network battery model was less than ±0. 01 V,which was more accurate,could better reflect the characteristics of the battery.