Theoretical Analysis of the Thermal Resistance Network for Battery Thermal Management

Battery thermal management for electric vehicles have gained significance over recent years, especially for the present lithium-ion batteries. However, high operating temperature and uneven temperature distribution inside the battery cell can significantly reduce capacity and lifetime. The temperature difference between the battery cells needs to be minimized to avoid premature aging of specific cells exposed to a higher temperature. The most common way to dissipate heat from the battery cells is to use air or liquid cooling. Air cooling is less complex than liquid cooling, but the extremely high ambient temperature dramatically limits the usage of air cooling. This paper developed a thermal connector that could be repeatedly assembled and disassembled between the battery cell. The thermal connector can effectively dissipate the heat into the refrigeration cycle while providing constant thermal resistance among the battery cells, which can be as lower as 0.115°C/W. Heat transfer through the thermal connector and refrigeration cycle were then calculated by applying different two-phase heat transfer correlations. Our results indicated that the overall heat transfer coefficient is around 7000.69 W/m²·K, which can be used to dissipate the heat of 20.01 kW. This research can provide the application of thermal connector with refrigeration cycle design in battery thermal management.