Application of DFSS for Optimizing Thermal Protection in Electric Vehicles During Battery Thermal Runaway Events

_________As electric vehicles (EVs) become increasingly prevalent, ensuring occupant safety during battery failure events—particularly thermal runaway (TR)—has become a critical aspect of vehicle design. TR in lithium-ion batteries involves a rapid escalation in temperature and the release of high-energy gases, which can result in intense heat transfer from the battery pack toward the cabin. If not properly managed, this heat can elevate cabin floor temperatures, posing risks to passenger safety and damaging interior components. A vital safety objective is to delay the transmission of heat from the battery enclosure to the vehicle floor, allowing sufficient time for occupant evacuation. This paper presents a robust design methodology using Design for Six Sigma (DFSS) principles to optimize the thermal protection system within the vehicle’s underbody. The approach identifies key design control factors that significantly affect heat propagation during a TR event. These control factors include the thermal conductivity and thickness of internal battery insulation, the emissivity of the battery’s top surface, the performance of a top-mounted heat shield, and the effectiveness of thermal resistance of vehicle floor shields. By systematically analyzing these parameters and applying statistical modeling, the study demonstrates how robust thermal protection design can enhance safety margins, reduce system variability, and ensure consistent occupant protection under worst-case thermal runaway scenarios. _______________________________