Optimal structure design and heat transfer characteristic analysis of X-type air-cooled battery thermal management system

Abstract

This paper develops an X-type double inlet and outlet symmetrical air-cooled battery thermal management system (BTMS) that overcomes the high temperature, large temperature difference, and high power dissipation problems. The proposed method extends previous symmetrical BTMSs, i.e., single inlet and outlet BTMS, single inlet and double outlet BTMS, and double inlet and single outlet BTMS. However, compared with the existing symmetrical BTMS, the suggested X-type BTMS improves performance and reduces the maximum temperature, maximum temperature difference, and maximum power dissipation by 4.33 K, 74 %, and 62.9 %, respectively. Additionally, the inlet and outlet parameters of the X-type BTMS are optimized with orthogonal analysis, and the optimum settings defined as 71 mm near the outlet, 135 mm near the inlet, 90° for the outlet angle, and 150° for the inlet angle, among which the outlet position and inlet angle significantly affect the performance of the BTMS. The original X-type BTMS is optimized to reduce the maximum temperature and maximum temperature difference by 4 K and 76.5 %, respectively. Furthermore, the heat transfer correlation expression for the X-type BTMS is obtained through theoretical analysis within an 8 % deviation, providing a reference for the design of BTMS.