Optimization design for improving thermal performance of T-type air-cooled lithium-ion battery pack

Abstract In order to solve the problems of high battery temperature and poor temperature uniformity of the battery pack in the process of high-intensity operation, an air-cooled T-type battery thermal management system (T-BTMS) was designed based on traditional U-type and Z-type. The charge and discharge process of lithium-ion battery was tested to obtain the key parameters of the battery, and the reliability of the computational fluid dynamic (CFD) method was verified by the air-cooled heat dissipation experiment of battery pack. Subsequently, the temperature and airflow distribution of the T-BTMS were simulated based on the validated CFD method. Compared with Z- and U- BTMS, the T-BTMS was more effective in improving the cooling performance and had lower power consumption. In this study, the effects of battery layout, top inclination, structural parameters of inlet and outlet, cooling ducts and controlled variables on the cooling performance of T-BTMS was explored. The results demonstrated that the structural design with the battery placed vertically (T-type I) and the top inclination angle of the battery box was 41.5° (Design 4) achieved better thermal performance. When the orthogonal test was further designed for the structural parameters of the inlet and outlet, the combination scheme of a1b5β5 had the best cooling effect, and the influence of the vertical length of the inlet was relatively large. When considering adding baffles in the cooling ducts and adjusting the cell spacings, the cooling performance of BTMS was greatly improved. Compared with the original model, the maximum temperature and maximum temperature difference were reduced by 2.2% and 90.8%, respectively.