Effect of Heat Pipe’s Configuration in Managing the Temperature of EV Battery

Abstract

Because of their high energy density and long cycle life, lithium-ion batteries are commonly employed in electric cars. As battery performance and life are highly dependent on temperature, it is critical to maintain the optimum temperature range. A battery thermal management system (BTMS) is critical for controlling the thermal behaviour of the battery. Air cooling, liquid cooling, direct refrigerant cooling, phase change material (PCM) cooling, and heat pipe cooling are all BTMS strategies. Heat pipes come in a variety of sizes and configurations that can be employed in the BTMS and many studies have proven the feasibility of using heat pipe as the electric vehicles’ BTMS. However, there are many aspects of the design and configuration of the heat pipe that could affect the overall thermal performance of the heat pipe BTMS such as its length, diameter, evaporator and condenser lengths, tilt angle, types of heat pipes and working fluids. In this work, a numerical study was conducted to investigate the effect of heat pipe’s diameter, number of heat pipes and the types of heat pipes on the thermal performance of the heat pipe BTMS. The diameter of the heat pipe varies between 6 – 12 mm, the number of heat pipes varies from 2 – 10 and the type of heat pipe considered in this work is straight heat pipe. The thermal performance of the heat pipe is measured by the maximum battery temperature and the thermal resistance at different battery heat generation rate in the range of 10 - 30W. The simulation model was validated against experimental data and results indicate excellent agreement between simulation and experimental data. Simulation results shows that the greater the diameter, the lower is the battery temperature. By increasing the heat pipe’s diameter, the battery temperature can be reduced by at least 10% or 3.4°C. Temperature reduction of at least 12.7% was observed when the number of heat pipes used in the BTMS increases.