不同诱发条件下NCM三元锂离子电池热失控和燃烧特性

目的 研究不同诱发条件下三元锂离子电池热失控和燃烧特性,科学认识海洋工程和装备领域储能电池的安全性,为海洋工程的消防安全设计提供理论依据。方法 模拟三元锂离子电池机械滥用和热滥用场景,分别用针刺和加热方式触发锂电池热失控,对不同带电状态(0%、25%、50%、75%、100%SOC值)的锂离子电池热失控过程中温度、电压、质量损失进行测量,对热失控后的电池进行拆解,并分析极片残余物的宏观和微观变化特征。结果 随着电池SOC值的增加,热失控反应强度增加,电池表面最高温度、温升速率和质量损失率均增大。针刺和加热触发电池热失控后极卷形态变化特征不同,分别呈“贝壳”和“月牙”形状。极片残余物的热重分析表明,50%SOC值和100%SOC值电池在针刺和加热后,极片残余物氧化分解后的质量损失比例分别为36.73%、18.75%和38.28%、30.38%。结论 三元锂离子电池的热失控行为随电池SOC值和诱发条件的改变而变化,高SOC值时,电池热失控反应更剧烈。一定条件下,针刺比加热更易触发电池热失控,而加热触发的热失控反应速率更快。热失控后的极卷形状变化和残余物热重分析可为火灾原因调查提供证据。

Thermal Runaway and Combustion Characteristics of NCM Ternary Lithium-ion Batteries under Different Induced Conditions

The research on the thermal runaway and combustion characteristics of ternary lithium-ion batteries under different induced conditions are helpful to understand the safety of energy storage batteries in the field of marine engineering and equipment, and provide a theoretical basis for the fire safety design of marine engineering. Mechanical abuse and thermal abuse scenarios of ternary lithium-ion batteries were simulated by acupuncture and heating respectively. The temperature, voltage and mass loss during thermal runaway of lithium-ion batteries with different state of charge (0%, 25%, 50%, 75% and 100%SOC) were measured. The batteries after thermal runaway were disassembled and the macroscopic and microscopic variation characteristics of the electrode residues were discussed. It is found that with the increase of battery SOC, the thermal runaway reactivity increases, and the battery surface temperature, temperature rising rate and mass loss rate also increase. The thermal runaway reaction of the two electrode coils triggered by acupuncture and heating are different, and the pair of electrode coils are shaped as "shell" and "crescent" respectively. The thermogravimetric analysis of the pole piece residues showed that the mass loss of battery of 50%SOC and 100%SOC were 36.73%, 18.75%, and 38.28%, 30.38%, respectively. Thermal runaway behavior of ternary lithium-ion batteries varies with battery SOC and induced conditions, and the thermal runaway reaction of batteries is more severe at high SOC. Under certain conditions, acupuncture triggers thermal runaway than heating more easily, but the reaction rate of batteries triggered by heating is faster. Informations on electrodes and thermogravimetric analysis of residues after thermal runaway can provide evidence for fire cause investigation.