Safety assessment for battery thermal runaway propagation for urban air mobility

Abstract Recent research on batteries has led to novel approaches for preventing TRP at both the module and pack levels. Since evidence for failure mechanisms and propagation processes is still emerging and limited, this study introduces a scenario-based framework to evaluate strategies for mitigating TRP. The focus is on the synergistic use of thermal barriers and liquid cooling systems in combination with a TRP containment mechanism. Four scenarios were analyzed under simplified assumptions to investigate whether the considered battery system could meet the safety targets for manned eVTOL and UAV applications. The results highlight the crucial role of TRP containment mechanisms, in addition to cell-to-cell TRP prevention techniques. Under the most conservative scenario, where no TRP containment mechanism is included, the safety targets could be achieved only for UAV applications with a moderate mass penalty. However, achieving the safety targets for manned eVTOL applications would require a TRP containment mechanism, which significantly increases the mass penalty. In more progressive scenarios, safety targets for both UAV and manned eVTOL applications could be met with a negligible mass penalty even without any TRP containment mechanism.