基于卡尔曼滤波的新能源汽车动力锂离子电池SOC估算方法

SOC Estimation Method for Lithium-ion Battery of New Energy Vehicle Based on Kalman Filter

由于进行新能源汽车动力锂离子电池SOC估算的过程中产生了滞回电压现象,导致锂离子电池SOC估算结果不准确,估算时间较长,为此提出一种基于卡尔曼滤波的新能源汽车动力锂离子电池SOC估算方法.采用双极化等效电路模型作为基础,加入二极管构建新能源汽车动力锂离子电池模型,消除滞回电压现象造成的理论误差;同时将模型离散化处理,辨识锂离子电池参数;根据参数辨识结果,采用卡尔曼滤波算法估计新能源汽车动力锂离子电池SOC状态.经实验测试结果表明,所提方法的SOC值相对误差基本控制在-0.5%~0.4%左右,所提方法不仅可以有效提升锂离子电池SOC估算结果的准确性,同时还能够有效减少估算时间.

Due to the hysteretic voltage phenomenon in the process of SOC estimation for lithium-ion battery of new energy vehicle,the SOC estimation results of lithium-ion battery are inaccurate and the estimation time is long.Therefore,a new method of SOC estimation for lithium-ion battery of new energy vehicle based on Kalman filter is proposed.Based on the dual-polarization equivalent circuit model,a new energy vehicle power lithium-ion battery model is constructed by adding diodes to eliminate theoretical errors caused by hysteretic voltage phenomenon.At the same time,the model is discretized to identify the parameters of lithium-ion batteries.According to the parameter identification results,the SOC state of Li-ion batteries for new energy vehicles is estimated by Kalman filter algorithm.The experimental results show that the relative error of SOC value of the proposed method is basically controlled within-0.5%-0.4%.The proposed method can not only effectively improve the accuracy of SOC estimation results of lithium-ion batteries,but also effectively reduce the estimation time.