Hermite插值法建立锂离子电池开路电压模型*

传统的开路电压(Open Circuit Voltage,OCV)模型建模方法中,利用最小二乘法拟合OCV曲线,使得OCV测试点不能落在曲线上,建模精度低,为此提出利用Hermite插值法建立电池OCV模型。首先通过对电池进行间隔放电获得若干个OCV测试点；其次利用分段三次Hermite插值函数建立OCV模型并拟合OCV曲线；最后验证所建立OCV模型的有效性。验证实验通过对电池进行不同温度下的UDDS动态工况放电实验,将OCV曲线应用在扩展卡尔曼滤波(Extended Kalman Filter, EKF)算法实现的电池SOC估算中,通过对比SOC估算结果验证OCV模型精度。实验结果表明,在不同温度下Hermite插值法OCV模型具有可行性,与传统OCV模型相比Hermite插值法OCV模型具有更高的建模精度。

Modeling of lithium-ion battery open circuit voltage by hermite interpolation method

In traditional Open Circuit Voltage (OCV) model modeling method, the OCV curve is fitted by the least squares method, so that the OCV test point cannot fall on the curve and the modeling precision is low. For this reason the use of Hermite interpolation method to establish the battery OCV model. Firstly, interval discharge of the battery is implemented to obtain several OCV test points. Then, piecewise cubic Hermite interpolation function is used to establish OCV model and the OCV curve is fitted. Finally, verify the validity of the established OCV model. Verify the experiment through the battery at different temperatures under the UDDS dynamic discharge test, and the OCV curve is applied to the SOC estimation of the EKF algorithm to verify the accuracy of the OCV model by comparing the SOC estimation results. The experimental results show that the Hermite interpolation OCV model is feasible at different temperatures. Compared with the traditional OCV model, the Hermite interpolation OCV model has higher modeling accuracy.