Comparison analysis of thermal behavior of Lithium-ion batteries based on a novel multi-modal composite immersion liquid cooling system coupled with fin/micro-heat pipe array

Immersion liquid cooling technology demonstrates significant potential for rapid heat dissipation from Lithium-ion batteries under extreme discharge conditions. To mitigate the effects of temperature inconsistency and liquid shock on battery life, a novel multi-mode composite immersion cooling (CILC) method is proposed in this study by combining static immersion liquid cooling (SILC) and conventional dynamic immersion liquid cooling (DILC). The cooling performances of both DILC and CILC modules were compared under various conditions. Compared to DILC, the CILC reduced the maximum temperature by 9.48 % and the temperature difference by 78.36 %. Notably, the temperature difference of the CILC remains relatively stable and is less influenced by coolant flow variations. Additionally, the concept of fluctuation effect was introduced to quantify the maximum temperature and temperature difference, enabling a deeper evaluation of the impact of various coolant types on the thermal equalization behavior of both DILC and CILC modules. The results indicate that the thermal equalization rate of DILC is low and experiences significant fluctuations. In contrast, CILC consistently demonstrates efficient and stable thermal equalization behavior. Furthermore, even under various failure scenarios, the CILC system retains its fundamental heat dissipation capabilities, effectively safeguarding the thermal integrity and stability of the module. Overall, the proposed CILC thermal solution outperforms traditional DILC in terms of heat dissipation uniformity, shock protection for battery surfaces, and stable thermal equalization behavior, providing a novel approach for the thermal management of immersed battery systems.