锂离子电池静置下阶跃放电电流动态模型

Dynamic Model for Step Current Discharge of Lithium-ion Battery after Rest

分析锂离子电池的一些特性时通常要电池的恒流放电曲线特性。目前工程上一般令电池输出阶跃电流以测取这个曲线,因此得到的电池电压特性是阶跃电流响应而不是恒电流响应。基于电化学理论中的控制电流法提出了建立锂离子电池阶跃电流响应模型的方法,分析了放电过程正极材料扩散系数的变化对电池端电压的影响,建立了数学模型并给出了模型参数的获取方法,还分析了模型参数随工作电流、环境温度以及电池荷电状态的变化规律。仿真和实物实验验证了模型的正确性。

The constant current discharge(CCD) curve of a battery is usually used to analyze some characteristics of the lithium-ion battery. However, in engineering practices, step current is generally managed to be output from the battery when measuring the CCD curve. Consequently, the battery's voltage characteristics are step current responses rather than CCD responses. In this paper, based on the controlled-current method in the electrochemical theory, a method to establish the step current response model of the lithium-ion battery is proposed. After the analysis of the influence of cathode material's diffusion coefficient variation on the terminal voltage, a mathematical model is established, and the calculation method for model parameters is given. In addition, the relations of model parameters with the operation current, ambient temperature, and the state of charge of the battery are analyzed. The proposed model was verified by both simulations and experiments.