Study of heat generation of a lithium-ion battery during discharge cycle

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.