Experimental and simulation study of a multichannel immersion cooling system for hot spot mitigation in energy storage batteries

The immersion battery thermal management (BTMS) system exhibits significant application potential in high-capacity energy storage systems. However, the inlet and outlet temperature effects of the coolant and the heat generation characteristics of lithium-ion batteries (LIBs) introduce spatial temperature differences and hot spots within the energy storage system. To address these issues, this study proposes and optimizes a multichannel immersion cooling system for hot spot mitigation (MICS) BTMS. The heat dissipation performance of MICS BTMS under different operating conditions was experimentally investigated. The influence of flow rate, module spacing, guide hole diameter, and guide hole position on heat transfer performance was studied through numerical simulations, and the interactions among the parameters were analyzed. The results show that in the heat transfer prioritized scheme, the maximum temperature of the battery module is 32.30 °C, 12% lower than that of the initial model and 23% lower than that of the static experimental system. The temperature difference prioritized scheme validates that increasing the flow rate does not lead to an increase in temperature difference. The balanced scheme achieves a low pressure drop of 135.37 Pa while maintaining a maximum temperature of 34.18 °C. In the optimized structure, the velocities in each guide hole and branch are significantly increased, with flow velocity variations between channels remaining within 6%. The optimized structure enhances the hot spot mitigation, reducing the average temperature difference between the tabs and the battery body to 0.63 °C. These results confirm the advantages of the MICS BTMS in addressing the issue of spatial temperature differences in immersion cooling.