三元锂电池荷电状态估计的传感器误差影响

Effect of sensor errors on state of charge estimation for ternary lithium-ion cells

锂电池荷电状态(SOC)的准确估计是电池管理系统的关键技术,为了解析传感器误差对SOC估计精度的影响,以二阶RC等效电路模型为基础,运用遗传算法进行参数辨识,采用扩展Kalman滤波算法进行SOC估计,分析电压、电流传感器存在的漂移和白噪声对SOC估计的影响。结果表明:电压、电流传感器的漂移与SOC估计误差的均值近似呈线性关系,电压、电流传感器存在的白噪声对SOC估计误差的均值无影响;对于实验中的三元锂离子电池,若使SOC估计精度在5%以内,电压的偏差值应控制在10 m V以内、电流偏差值应在1/30 C以内。

The accurate estimation of state of charge（SOC） of lithium-ion cells is the key technology of battery management system. The influence of SOC estimation accuracy with the drift or white noise of voltage or current sensor was analyzed to determine the sensor errors on the accuracy of SOC estimation using genetic algorithm to identify model parameters and extended Kalman filter based on the second-order RC equivalent circuit model. The results show that the relationship between offset values and the mean of SOC estimation error has an approximately linear when the voltage or current sensor has drift, but the white noise of the voltage and current sensors has no influence on the mean of the SOC estimation error. If the estimation accuracy of SOC is less than 5% for lithium-ion cell used in the experiment, the voltage and current offset should be controlled respectively within 10 m V and 1/30 C.