Experimental study on failure behaviors of cylindrical lithium-ion batteries under high-velocity impact loading

Lithium-ion batteries are extensively utilized in civilian and military fields. However, their safety under extreme conditions (e.g., high-velocity impacts) remains to be further investigated. Cylindrical cells behave as the fundamental units in numerous electronic devices and energy-storage systems. This study investigates two types of cylindrical lithium-ion batteries (i.e., 18650 and 21700) and propels high-velocity projectiles into the batteries, thereby simulating extreme impact scenarios. We experimentally examine the failure behaviors of these batteries across the full state of charge (SOC) range, that is, from 0 to 100% at 10% intervals. Our results reveal that higher SOCs lead to more severe failure failures and significantly elevate the risk of thermal runaway (TR) following the battery penetration. Different battery types exhibit almost identical capacity threshold for thermal runaway. This study introduces the BiHill function model to simulate the temperature evolutions during the thermal runaway processes of high-SOC batteries. Additional experiments were conducted to investigate the effect of velocity on the thermal runaway threshold. Our results are expected to provide theoretical foundation for the safety protection of LIB in extreme environments.