Safety analysis of lithium-ion batteries under mechanical shock conditions

The harsh and confined environment of underground coal mines makes lithium-ion batteries vulnerable to external physical shocks or damage, potentially leading to safety incidents. This study investigated a 100 A·h lithium manganese oxide ion battery designed for mining applications, employing puncture, high-temperature, and humidity tests to evaluate its safety performance. The puncture test simulated mechanical shocks typical in coal mine environments by penetrating the battery with a sharp object and observing its response under extreme conditions. A furnace and humidity-controlled environment chamber were also utilized to replicate the high-temperature and humid conditions encountered in coal mines, assessing the battery's safety and reliability post-puncture. The results revealed the following: ① After puncture by a tungsten needle, the battery exhibited surface deformation and cracking, but no electrolyte leakage, smoke, fire, or explosion occurred, with no gas generation inside. Although the temperature of the punctured battery rose significantly, it remained within a safe range without igniting or exploding, indicating a certain level of thermal stability suitable for coal mine applications. ② The punctured battery expanded notably when heated in the furnace, accompanied by gas leakage; however, no explosion or combustion took place, suggesting thermal stability under specific conditions. ③ In a humid environment, the punctured battery produced gas, leading to increased internal pressure. The combination of puncture and humidity raised the battery's temperature, but the moisture acted as a cooling agent, resulting in a slower temperature increase compared to high-temperature conditions, without triggering explosion or combustion. This indicated that the battery maintained thermal stability in humid environments and did not exhibit thermal runaway.