A new design of cooling plate for liquid-cooled battery thermal management system with variable heat transfer path

Liquid-cooled battery thermal management system (BTMS) is of great significance to improve the safety and efficiency of electric vehicles. However, the temperature gradient of the coolant along the flow direction has been an obstacle to improve the thermal uniformity of the cell. In this study, a BTMS design based on variable heat transfer path (VHTP) was developed and applied to prismatic cells. Compared with the reference liquid cooling plate, the variable heat transfer path design changes the heat transfer path between the coolant channel and the battery surface by setting a reasonable groove, thereby changing the basic feature that the battery surface temperature rises monotonously along the flow direction. The geometric parameters of the trench are optimized. The results show that grooves with d1 = 0, d2 = 26 mm, d3 = 57 mm, and d4 = 0 are the best VHTP designs to improve thermal uniformity. The optimized VHTP cooling plate reduces the temperature difference across the battery surface by 22.7 % to 25.4 % for different discharge rates and cooling fluid mass flow rates, while slightly improving the maximum temperature on the battery surface, compared to the reference cooling plate.