基于Li分布特性的锂电池放电容量研究

Study on Discharge Capacity of Lithium-Ion Batteries Based on the Li Distribution Characteristics

本文采用锂电池多尺度耦合模型对不同工况下放电的电极颗粒内部Li浓度分布特性进行了研究,并根据放电过程中的Li脱嵌量对放电容量进行了估算。结果表明:在1 C放电电流下,当环境温度较低(0~25℃)时,锂电池放电容量随环境温度的升高而迅速增大,当环境温度较高(25~40℃)时,放电容量基本不随温度变化;在25℃的环境温度下,当放电电流较小时(0 C^4 C)时,放电容量随放电倍率的增大而减小,而当放电电流较大(4 C^10 C)时,锂电池放电容量随放电倍率的增大基本不变。

The distributions of Li concentration in the electrode particleare simulated by a multi-scale coupling model of lithium-ion batteries during discharging at different operating conditions.This paper have estimated the discharge capacity on the basis of the amount of de-intercalated/intercalated Li from the electrode particles.With fixing discharge current at 1 C,the discharge capacity decreases rapidly as the ambient temperature decreases from 25° C to 0℃,while it changes little when the temperature increases from 25℃ to 40℃.Correspondingly,the discharge capacity decreases as the discharging current increases from 0 C to 4 C with keeping the ambient temperature at 25℃,while it basically remains unchanged as the discharging current increases from 4 C to 10 C.