Numerical investigation of the performance of a hybrid battery thermal management system at high discharge rates

Abstract

In this research study, a comprehensive numerical study was conducted to investigate the thermal behavior of a hybrid battery thermal management system (BTMS) that involves air and phase change material (PCM) cooling. Analyses were carried out by considering three different PCM thicknesses of 4 mm, 6 mm, and 8 mm, two different types of PCM, and three different Reynolds (Re) numbers of 100, 200, and 400 at four different discharge rates of 3C, 5C, 7C, and 9C. The enthalpy method was used, and the analyses were performed by using COMSOL Multiphysics. In the analysis, 60 °C was determined to be the upper limit temperature, and BTMS was optimized by the type of PCM, Re number, and PCM thickness for this temperature. The results indicate that PCM-2 has a better cooling effect due to its relatively high thermal conductivity. Both PCM-1 and PCM-2 were sufficient for all thicknesses at 3C and 5C discharge rates. However, PCM-1 was insufficient for all three thicknesses at 7C and 9C discharge rates. In contrast, PCM-2 was sufficient for a thickness of 4 mm at 7C and a thickness of 6 mm at 9C. Moreover, with the use of PCM, the difference between the minimum and maximum temperature in the BTMS was kept below 5 °C in the case of a 400 Re number and a 4 mm PCM thickness at all four discharge rates.