Multi-objective optimization of immersion cooling system for large-capacity lithium-ion battery with collaborative thermal management structures

The efficient thermal management of large-capacity energy storage batteries is a critical technical challenge to ensure their safe operation and support the implementation of national energy strategies. This study proposes a novel immersion liquid cooling system that integrates structural components such as support bars, spacer strips, and flow stabilizing block to form collaborative heat dissipation channels at the bottom, sides, and top of the battery module. High-performance hydrocarbon oil is used as the cooling medium to enhance heat exchange efficiency. Compared to cold plate liquid cooling, the proposed immersion cooling system offers superior performance, reducing the maximum temperature, temperature difference, and pressure drop by 51.91 %, 51.72 %, and 3.64 % over the parallel channel, and by 50.61 %, 51.52 %, and 94.23 % over the S-sharped channel. Key design variables are identified through sensitivity analysis, and a multi-objective optimization methodology is employed to refine the immersion cooling structure. The optimized solutions achieve reductions in maximum temperature (2.3 %–6.21 %) and temperature difference (5.37 %–10.32 %) while simultaneously decreasing the immersion liquid consumption by 7.8 %–31.5 %. Experimental validation shows that the maximum deviation between simulation results and test data is less than 1.76 °C, confirming the accuracy and reliability of the proposed design method.