NCM622三元动力电池热失控蔓延抑制的实验与建模研究

Experimental and Modeling Study on Thermal Runaway Propagation Inhibition in NCM622 Ternary Lithium-Ion Batteries

当动力电池系统内某一节电池在遭到热滥用或机械滥用的条件下,可能发生热失控,瞬间在电池系统内释放大量热量,导致多节电池发生多米诺骨牌式的热失控。同时,热失控释放的高温气体在电池系统内聚集会有潜在爆燃的风险。气凝胶因其隔热性能良好、成本低、结构稳定等优点,是作为阻隔热失控扩散的理想材料。本研究对大容量方壳三元锂电池展开了从单体、模组实验与建模研究,通过实验验证了同时使用气凝胶在抑制电池系统热失控蔓延方面的有效性。结果表明,引入气凝胶可以明显地降低电池组的温度上升,使热量被限制在局部区域内,防止热失控传播到相邻的电池单元。电池系统内部发生部分电池热失控后,喷发的高温气体需要快速疏导排出系统内以降低热灾害。最后建立电池系统内部热失控高温气体喷发流动3D模型。该模型模拟了两节电池依次热失控后高温气体在系统内的流动情况,为后续的电池系统安全结构设计提供思路。

In a power battery system, under conditions of thermal or mechanical abuse, a single cell may ex-perience thermal runaway, releasing a substantial amount of heat within the battery system in-stantly. This can lead to a domino effect of thermal runaway across multiple cells. Simultaneously, the high-temperature gases released during thermal runaway pose a potential risk of combustion within the battery system. Aerogels, due to their excellent thermal insulation, low cost, and struc-tural stability, are considered an ideal material for inhibiting the spread of thermal runaway. This study focuses on large-capacity ternary lithium-ion batteries, conducting experiments and model-ing at the individual cell and module level. Experimental validation confirms the effectiveness of using aerogels to suppress the propagation of thermal runaway in the battery system. The results indicate that introducing aerogels significantly reduces the temperature rise of the battery pack, confining the heat to a localized area and preventing the spread of thermal runaway to adjacent battery units. In the event of partial thermal runaway within the battery system, rapid venting of the high-temperature gases is necessary to mitigate thermal hazards. Finally, a 3D model depicting the flow of high-temperature gases expelled during thermal runaway within the battery system is developed. This model simulates the flow of high-temperature gases after sequential thermal run-away events in two cells, offering insights for the design of safety structures in future battery sys-tems.