Study on the Safety Performance Parameters of Lithium-Ion Batteries Under Unconventional Extrusion Conditions

The safety issues of lithium-ion batteries under mechanical abuse conditions have earned widespread attention due to their high uncertainty and risk. In this article, extrusion tests were conducted on 10 Ah pouch cells, with different indenter shapes, loading locations, and state of charge (SOC). The voltage changes, temperature changes during the loading process, and microscopic structural changes of the cell electrodes after extrusion tests were analyzed to investigate the impact of different test conditions on the safety performance parameters of the cells. The tests included various unconventional locations that cannot be achieved under standard experimental conditions for lithium-ion batteries, better simulating the random collisions that lithium-ion batteries may experience in real-world scenarios. The results show that a sharp indenter induces earlier internal short circuits in the cells compared to a blunt indenter, leading to more severe thermal runaway reactions. Higher SOC is associated with faster average temperature rise rates, increased risk of thermal runaway, and more pronounced voltage drops at the moment of internal short circuits. The research results provide theoretical insights into the failure mechanisms of cells under mechanical abuse and offer valuable guidance for improving cell safety design.