Investigating the Effect of Hydrogen-Helium Blends on Thermal Management Efficiency in Battery Systems

An effective battery thermal management system (BTMS) is crucial for ensuring the safety, longevity, and performance of lithium-ion batteries (LIB) in electric vehicles (EVs). This study investigates the performance of BTMS using innovative gas mixtures of hydrogen and helium as coolants. The research focuses on varying concentrations of these gases, with hydrogen to helium ratios ranging from 90:10 to 60:40 in 10% increments of helium. The integration of inert helium with hydrogen mitigates flammability risk and effectively maintains optimal LIB operating conditions. The thermal performance of immersion cooling for a cylindrical LIB cell (4000 mAh) was evaluated using computational fluid dynamics (CFD) software (ANSYS Fluent). Temperature response and power consumption were analysed at a high discharge rate of 2C, with varying coolant inlet velocities (0.5 m/s, 1 m/s, 5 m/s, and 20 m/s) and helium concentrations. A key finding of the study is that higher concentrations of helium led to a trade-off in BTMS performance: while improving safety, thermal performance slightly decreased, and pressure drop increased. These effects are attributed to the increased density of the gas mixture, which heightens frictional losses and flow resistance. Across all test scenarios, the maximum LIB temperature was consistently maintained below the threshold of 40°C. This finding reinforces the effectiveness of the gas mixture strategy in ensuring both safe operation and reliable performance of LIB in EVs.