基于COMSOL的三元锂离子电池穿刺热失控行为研究

基于COMSOL的三元锂离子电池穿刺热失控行为研究摘要锂离子电池由于较好的循环性能、更大的能量密度等优点，在人们的生产生活中，尤其是新能源汽车等领域的运用越来越广泛。但与此同时锂离子电池也存在着热安全性不足，过电、过热、穿刺等条件触发的电池热失控，可能引发火灾甚至爆炸等继发事故，这不仅不利于保护锂电池应用场景下人们的生命财产安全，也限制了锂离子电池在各领域的广泛应用。针刺热失控是锂离子电池热失控三种触发方式中最为严酷和直接的，因为其能有效模拟电池内短路情况而被广泛用于评估锂离子电池在作为电动汽车动力电池并遭遇撞击时的稳定性和安全性。通过钢针刺入电池引发的电池内部短路，导致本体存储能量快速异常释放，造成大量的热产生和积聚，并引发一系列电池中的副反应，最终造成锂离子电池热失控。所以，本文针对三元锂离子电池针刺下热失控机理进行研究，并利用COMSOL建立热失控模型，探究不同穿刺材料与穿刺直径对三元锂离子电池热失控的影响。研究发现，电池发生热失控时的温度-时间随曲线趋势对穿刺材料与穿刺直径不敏感，但不同的穿刺直径会导致电池的温度升高速度与升温顶点出现差异，穿刺直径大时温度升高更快，最高温度也更高：不同的穿刺材料对电池温度的影响也类似，就最高温度而言，穿刺材料对电池热失控的影响要大于穿刺直径。关键词安全工程：锂离子电池：热失控IResearch on thermal runaway behavior of ternarylithium-ion battery puncture based on COMSOLAbstractLithium-ion batteries are more and more widely used in people's productionand life,especially in the fields of new energy vehicles,because of their bettercycle performance and greater energy density.However,at the same time,lithium-ion batteries also have insufficient thermal safety,and the thermalrunaway of the battery triggered by overelectricity,overheating,puncture andother conditions may cause secondary accidents such as fire and even explosion,which is not only conducive to protecting the safety of people's lives andproperty in the application scenario of lithium batteries,but also limits the wideapplication of lithium-ion batteries in various fields.Acupuncture thermal runaway is the most severe and direct of the threetrigger ways of lithium-ion battery thermal runaway,because it can effectivelysimulate the short-circuit situation in the battery,and is widely used to evaluatethe stability and safety of lithium-ion batteries when they are used as electricvehicle power batteries and are hit.The internal short circuit of the batterycaused by the steel needle stabbing into the battery leads to the rapid abnormalrelease of the body stored energy,causing a large amount of heat generation andaccumulation,and triggering a series of side reactions in the battery,and finallycausing the thermal runaway of the lithium-ion battery.Therefore,this paper studied the thermal runaway mechanism of ternarylithium-ion battery under acupuncture,and established a thermal runaway modelwith COMSOL to explore the influence of different puncture materials andpuncture diameter on the thermal runaway of ternary lithium-ion battery.It was-Ⅱ-found that the temperature-time curve trend of the battery when thermalrunaway occurred was insensitive to the puncture material and puncturediameter,but different puncture diameterwould lead to differences between thetemperature rise rate and the temperature rise peak of the battery.When thepuncture diameter was large,the temperature rise was faster and the maximumtemperature was higher.Different puncture materials have a similar effect on thetemperature of the battery,and for the maximum temperature,the puncturematerial has a greater effect on the thermal runaway of the battery than thepuncture diameter.Keywords Safety engineering,Lithium-ion battery,Thermal runaway-川-目录摘要Abst