Analysis of the Battery Direct Cooling Thermal Management System Coupled with Passenger Cabin Air Conditioning in Extended-Range Vehicles

To investigate the characteristics of a battery direct-cooling thermal management system integrated with the passenger compartment air-conditioning in a range-extended hybrid electric vehicle (REV), a model of the vehicle’s direct-cooling and liquid-cooling thermal management systems was established in GT-SUITE software. The findings are as follows: (1) Under high-temperature fast-charging conditions, the direct-cooling thermal management system exhibited improved performance indicators compared to the liquid-cooling system. Specifically, the charging time was reduced by 3.8%, the maximum heat exchange power increased by 27.33%, the battery temperature decreased by 2.37°C, the thermal decay rate was only 6%, and the average system energy efficiency ratio increased by 8.37%. (2)The outlet pressure of the direct-cooling plate significantly affected the temperature reduction of the battery pack during high-temperature fast-charging. The results indicated that within a certain range, a lower outlet pressure of the cooling plate led to a greater average temperature reduction of the battery pack. (3)Under high-speed cruising conditions, the direct-cooling thermal management system also demonstrated improved performance indicators compared to the liquid-cooling system. Notably, the average temperature reduction of the battery pack increased by 18.8% with the direct-cooling system. The inlet water temperature of the electric motor and the temperature reduction in the passenger compartment were nearly identical and met thermal safety requirements. (4)Significant differences in battery pack temperature reduction were observed under three thermal balance conditions with the direct-cooling thermal management system. Specifically, the temperature reduction was smallest during high-speed cruising and largest during high-speed climbing, with an increase of 13.52% compared to high-speed cruising. This study provides a theoretical basis for the practical application of direct-cooling thermal management systems in range-extended vehicles.