计及非线性容量效应的锂离子电池混合等效电路模型

摘要

Based on the Thevenin equivalent circuit model of the lithium ion battery, a state-of-charge ( SOC)part is added into the model, so as to improve the accuracy of SOC estimation and to embody the nonlinear capacity effect of the lithium ion battery. The battery capacity is divided into two parts, i. e. the available capacity and the unavailable capacity, the introduction of which appropriately describe the rated capacity effect when the battery is working and the recovery effect when the battery is not working. Meanwhile,a new definition of the SOC is given to estimate the SOC of the battery through the state-of-charge part of the proposed model in real-time. And a one-to-one relationship is built up between the open circuit voltage of battery and the SOC. Moreover,the second-order polarization RC network in the Thevenin equivalent model is upgraded into a third-order one,with real physical significance added to the third-order RC network in order to make the polarization effect more accurate. Finally,the simulation waveforms within Simulink indicate the validity of the proposed model.%为提高荷电状态（ SOC）估计的精度，对锂离子电池戴维宁（ Thevenin）等效电路模型进行了改进。在此模型基础上增加了荷电状态部分，从而使得锂离子电池的非线性容量效应得以体现。将电池的容量分为可用容量与不可用容量，电池容量一分为二的引入能很好的体现电池工作时的额定容量效应、不工作时的恢复效应以及时刻存在的自放电效应。同时，对SOC进行了新定义，通过荷电状态部分的模型来实时估计电池的SOC值，并建立SOC与开路电压之间的一一对应关系。另外，将戴维宁模型中的二阶极化RC网络升级为三阶，并赋予这三阶RC网络实际的物理意义，从而更精确的反映电池的极化效应。最后通过Simulink仿真与实验分析验证了所提出模型的正确性。