A Cooling Strategy to Suppress Thermal Runaway in Lithium-Ion Battery Systems

Lithium-ion batteries are essential for electric vehicles and energy storage systems owing to their high energy density and long cycle life. Nonetheless, thermal runaway (TR) remains a critical safety challenge: excessive heat from abuse conditions can trigger exothermic reactions that propagate across cells, leading to catastrophic module failure. This study presents a three-dimensional thermal model of a pressurized air cooling system designed to enhance heat dissipation and suppress runaway propagation in large-scale battery packs. A Tesla Model S module is used for model validation. The influence of airflow conditions and initial failure locations on propagation behavior is systematically investigated. Results show that higher Reynolds numbers (Re) reduce the temperatures of cells adjacent to the failure site, effectively slowing propagation, while sidewall failures generate higher temperatures due to additional radiative heat. Under normal operation, pressurized cooling with Re above 21,000, corresponding to a heat transfer coefficient of 65 W/m²·K, maintains both peak temperature and temperature uniformity within safe operating limits. TR propagation across the module is fully suppressed when Re exceeds 48,000. These findings highlight the effectiveness of pressurized air cooling in mitigating TR risks in large battery modules.