基于恒流充放电测量的锂离子电池内阻估计

Estimation of internal resistance of lithium ion battery based on constant current charge and discharge measurement

针对准确测量锂离子电池内阻的需求,提出一种基于恒流充放电测量的内阻估计方法。该方法通过分析电路模型的串并联结构特性,采用方波恒流源激励锂电池获得充放电输出响应,利用充放电状态切换产生的电压跳变估计欧姆内阻,再通过差分和对数变换,将阻容回路参数估计问题建模为直线拟合问题,降低问题求解的难度。通过软件仿真和实测数据分析验证该方法的有效性,与现有测量方法相比,该方法能有效消除单频点测量引起的不同相问题,具有测量准确、简单可靠的优点,在实际测量中获得较好的使用效果。

In order to accurately measure the internal resistance of lithium ion batteries,a method of internal resistance estimation based on constant current charge discharge measurement is proposed.By analyzing the series and parallel structure characteristics of the circuit model,a square wave constant current source is used to stimulate the lithium battery and the charge and discharge response is acquired.The voltage jump generated by the state switching between charge and discharge is used to estimate the ohm internal resistance,and then the parameter estimation problem of the resistance and capacitance loop is modeled as a linear fitting problem by means of difference and logarithmic transformation,which reduces the difficulty of the problem solving.The validity of the method is verified by software simulation and measured data analysis.Compared with the existing measurement methods,this method can effectively eliminate the different phase problems caused by single frequency point measurement and bring about accurate result via simple and reliable measurement,which is effective in practical measurement.