锂离子电池放电循环的发热特性研究

Study of Heat Generation of a Lithium-Ion Battery During Discharge Cycle

锂离子电池发热特性的研究对于发展电池热管理系统具有重要意义.本文采用数值方法对锂电池放电过程中的微观发热特性进行了研究,并对锂电池放电循环过程中固体电解质(SEI)膜和欧姆热的变化规律进行了分析,研究结果表明:锂电池以高倍率(>5C)放电时,SEI膜产生的热量是锂电池发热的重要部分;随着放电循环的进行,锂电池负极颗粒表面SEI膜以线性规律增厚,导致电池SEI膜电阻不断增大;锂电池放电环境温度越高,锂电池负极SEI膜增厚越快,容量衰退越快。

To understand the heat generation characteristics of a Li-ion battery is of great importance to develop the battery thermal management system.This paper presents the study on heat generation characteristics at microcosmic level for the discharge of a Li-ion battery via the numerical simulations.The changes of the solid electrolyte interphase(SEI) and ohmic heat are studied as growing of battery charge/discharge cycles.The results show that the ohmic heat producing from the SEI is the considerable heat source when the battery discharge rate is larger than 5C.The thickness of SEI on the negative electrode grows lineally with increasing of cycle number and the resistance of SEI presents linear increasing as well.The higher the battery discharge temperature is,the more quickly the negative SEI thickens,and the faster the cycle life of a battery shortens.