基于积分变换的锂电池系统建模

Lithium battery system modeling based on an integral transform method

Gassing锂电池模型考虑了电化学反应的析气和温度影响,描述了锂电池系统的非线性时变特性,使模型的适用范围拓广至SOC>85%的临界情况。通过积分变换,用能量状态W0代替原状态变量开路电压U0,将表征锂电池重要特性的SOC-OCV曲线转换成SOC-W0曲线,同时进一步考虑了倍率充放电效应,提出了改进型Gassing模型。仿真结果表明,改进型Gassing模型不仅能适用于SOC-OCV曲线中间区域平坦的磷酸铁锂电池,还进一步提高了模型的仿真精度及SOC计算的合理性和有效性。

The gassing lithium battery model that considered the influence of gassing and temperature on battery electrochemical reaction,described the nonlinear and time-varying characteristics of lithium battery systems,and made its applicable scope extend to the critical situation of SOC ＆gt; 85%.With an integral transform method,the original state of open voltage U0 was replaced by the energy state W0,and the SOC-OCV curve that described the battery’s important characteristics was transformed into the SOC-W0 curve.Finally,an improved gassing model was developed,additionally considering the effect of charge and discharge rate.The simulation results show that the improved gassing model can not only be well applied to lithium iron phosphate battery whose SOC-OCV curve is flat in its middle working area,but also improve the rationality and validity of the SOC calculation.