Mechanical and electrical degradation of impaired batteries after impact loading

Lithium-ion battery combustion accidents are known for their rapid onset and difficulty in extinguishment, raising significant safety concerns in environments with collision risks. These risks highlight the need for stringent damage assessment and failure prediction methods for power batteries. While severe collisions can cause immediate catastrophic damage and thermal runaway, most collisions occur at low speeds, where the impact may result in only minor external deformation without immediate failure. However, the potential safety risks associated with the continued use of batteries after such minor collisions are not well understood. Current research and battery safety standards primarily focus on immediate or short-term failure after impact, leaving a gap in understanding the long-term effects of low-energy collisions on battery safety. This study addresses this gap by investigating the influence of low-energy collisions on the safety and reliability of lithium-ion batteries. A shock-compression sequential loading experiment was used to evaluate the mechanical response and failure behavior of pouch batteries under dynamic loading. The study also explored the deterioration of batteries subjected to weaker impact loads through electrochemical performance testing and internal structural damage analysis. The results reveal that even if a battery does not fail immediately under low-impact energy, its internal mechanical integrity may still be compromised, leading to a lower failure threshold under subsequent loads. Significant deterioration in capacity and internal resistance was observed, with the ability to withstand secondary loads of the battery and its electrochemical performance declining as impact energy increased. This indicates a clear correlation between impact-induced deformation and overall battery performance. The study also proposes a quantitative evaluation method for assessing the battery's condition after minor impacts, offering a valuable tool for predicting the risks associated with reusing impacted batteries. These insights are essential for understanding the response mechanisms of lithium-ion batteries under low-energy collision conditions and optimizing safety standards for their continued use in collision-prone environments.