Improvement of cooling performance and mitigation of fire propagation in lithium-ion batteries using a novel gas-cooled thermal management system

The development of battery thermal management system has become significant because an inappropriate temperature operating condition is the major reason for deteriorating battery lifetime and causing battery explosions. This paper aims to propose a novel alternative battery thermal management system by using an inert gas as an alternative coolant instead of air to improve the cooling performance and prevent battery thermal runaway and fire propagation. The test section of the 18650 cylindrical lithium-ion battery modules was designed and tested to assess the thermal behavior. Ansys Fluent was employed to investigate the cooling performance of battery thermal management system, while the fire dynamics simulator observed the fire propagation when the battery was encapsulated with various inert gas coolants. The inert gas can exhibit better cooling performance than air. It succeeded in declining the maximum temperature and increasing the convective heat coefficient. Increased turbulent flow aided in the improvement of the heat transfer process as measured by Nusselt number. Although all gas coolants in this study can successfully manage the cell temperature lower than 60°C which was the starting temperature of thermal runaway, but high Reynolds number of coolant flowing was required. Otherwise, helium can act as the best coolant to transfer heat out of the battery even at a very low Reynolds number. The mitigation of fire propagation on the battery can be achieved when the battery was surrounded with inert gas. The use of the air-cooling system initiated the fire explosion when the battery thermal runaway occurred.