Performance improvement of thermal management system of lithium-ion battery module on purely electric AUVs

A paraffin-dominated battery thermal management system (BTMS) is developed in this work, to protect the Li-ion battery (LIB) module from thermal runaway and improve the output performance of autonomous underwater vehicles (AUVs). First, a physical model is established for analyzing the transient heat transfer process and corresponding thermal behavior, occurring in the AUV's battery module during its charge/discharge cycles. Second, numerical calculations are performed by using a pressure-velocity coupled algorithm based on a finite volume solver, to reveal heat dissipation and temperature distribution on the battery module cooled by the paraffin-dominated BTMS. Third, the calculation results are verified comparing with the open literature data. It indicates that air-dependent thermal resistance in the battery module causes an inevitable temperature rise and nonuniformity accounting for potential thermal runaway. Also, the customized RT48 paraffin mixture with a melting temperature range from 321.0 K to 325.0 K is high-efficiency to maintain the optimal working temperature and temperature difference for the battery module. In conclusion, a well-controlled phase change temperature range and equivalent thermal conductivity combined with the optimized charge/discharge strategy is exceedingly crucial for guaranteeing thermal safety and high performance regarding the AUVs. Besides, the research findings are in good agreement with the open literature data.