Electrochemical degradation of defective lithium-ion batteries under mechanical vibration

The electrochemical stability of defective batteries induced by mechanical abuse raises serious safety concerns. However, their performance under realistic vibration conditions, a critical operational scenario, remains insufficiently understood. In this work, we systematically investigate the vibration-induced electrochemical degradation behavior and associated failure mechanisms of mechanically defective LIBs by combining the experiments and morphological characterization. The defective batteries were prepared through quasi-static indentation and flat compression. Subsequently, mechanical vibration excitation was applied on defective LIBs during charge-discharge test to investigate its influence on electrochemical performance characteristics. The indentation defective batteries exhibit a specific vibration acceleration threshold beyond which the capacity starts to decreases. Furthermore, vibration durability test was performed on the defective batteries to explore their electrochemical degradation during sustained vibration loading. And a comprehensive post-mortem analysis was conducted on the battery components to establish structure-property relationships for the observed degradation behavior. Besides, an acceleration-dependent vibration durability threshold model was proposed based on the experimental data to supply guidance for engineering application. The effects of defect type, state of charge (SOC) and charge-discharge rate were also discussed. These findings reveal the performance evolution behavior and critical thresholds of slightly deformed batteries under vibration, providing fundamental insights for safety warning systems and degradation prediction. Furthermore, the results establish a scientific basis for establishing battery application and retirement standards, thus supporting the development of a circular economy for lithium-ion batteries.