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.

Metamaterials with both reversible deformation and a long load plateau meet the demand for cyclic buffering, offering great application prospects in protective engineering. However, current metamaterials generally suffer from low material utilization, which limits their load-bearing and energy absorption performance. To address these limitations, a novel buffering metamaterial with a long load plateau is proposed in this work. Composed of bilaterally symmetric double-arc structures and vertically symmetric curved plates, the metamaterial is capable of recoverable large deformation and overall cooperative load-bearing deformation, thereby improving material utilization and optimizing structural load capacity and energy absorption performance. Experimental tests and numerical simulations were conducted to validate the long load plateau and recoverable large deformation characteristics of the metamaterial. The influences of structural geometric parameters on its mechanical behavior were also systematically analyzed. The results indicate that the long load plateau can be effectively tuned by adjusting the thickness of lateral double arcs, the thickness of intermediate curved plates, and the central transverse span. Once the intermediate curved plates are removed, the long load plateau feature disappears, and the force-displacement curve presents an approximately linear variation. Finite element simulations at equal mass confirm that the proposed metamaterial possesses better buffering performance than similar structures without a long load plateau, and the underlying buffering mechanism is clarified. The findings provide a novel design strategy for improving the performance of metamaterials with a long load plateau, and facilitate their application in protective engineering.