A comparative investigation of two-phase immersion thermal management system for lithium-ion battery pack

The applications of lithium-ion batteries (LIBs) still suffer from thermal sensitivity and safety issues, especially given the rigorous requirements of fast charging and discharging. When choosing a proper battery thermal management system (BTMS), a comprehensive investigation should be made in terms of design complexity, system cost, and cooling efficiency, which usually forms a trade-off. In this study, four types of BTMS including air cooling, single phase immersion, indirect cooling, and two phase immersion are first evaluated on pouch battery pack. To describe the uniform heat generation, batteries are simulated by a three-dimensional electrochemical-thermal coupled model. Results show that air cooling and immersion cooling exhibits less extra weight, while two phase immersion delivers better in suppressing temperature rise and maintaining temperature uniformity. Then, the simulations involving different coolants are conducted for two phase immersion-based BTMS. The thermal behaviors of battery pack are examined at 5, 7, and 9 C discharge rates. The R1336mzz(Z) coolant with high boiling heat transfer coefficient is suitable for thermal management at high discharge rates. Besides, analysis reveals that increasing the immersion level of battery pack can improve battery temperature behaviors. This work is expected to provide preliminary proof of BTMS design for fast discharging.