Research on the Influence of Liquid on Heat Dissipation and Heating Characteristics of Lithium-Ion Battery Thermal Management System

A battery thermal management system (BTMS) with functions of heat dissipation and heating by using only one liquid and one structure was studied, and a design for a new type of thermal management device structure was proposed. To find the influence factors of the BTMS on heat dissipation and heating characteristics, we selected and simulated three parameters: inlet size, liquid flow rate, and temperature. The convective heat transfer coefficient h and the Nusselt number Nu were used to analyze the influence of inlet size and liquid velocity on heat transfer intensity. The results show that: (1) In the temperature environment of 298 K with different discharge rates, a pipe diameter of 10 mm is the best size of the BTMS; (2) The increase in flow rate can increase the convective heat transfer coefficient h and the Nusselt number Nu. When the flow rate is 0.02 m/s, the growth rate of h and Nu is the largest; (3) The higher the fluid temperature, the faster the temperature of the battery pack increases in cold environments, but the uneven surface temperature of the battery is also more obvious.