锂离子电池过充着火机理及能量释放规律研究

Lithium-ion batteries are characterized by high energy density, long cycle life and environmentally friendly. Their market scale and application fields are expanding. Frequent safety accidents make their safety problems more and more serious. Air shock wave and combustion are two main disaster effects of safety accidents. In this proposal, it will focus on the key scientific issues of the formation and evolution of air shock wave and combustion flame.   The time-space coupling relationship between explosive air shock wave and combustion flame under overcharge will be studied on the base of the knowledge of the reaction process of lithium-ion battery components using experimental and numerical simulation methods. We will study the relationship of the structure-performance-charge of battery components in order to obtain the key step of battery failure, the three-dimensional electrothermal model coupled with overcharge current to understand the heat release law of battery, the influences of capacity and overcharge current on characteristic parameters of flammable fluid overflow to get the evolution process of air shock wave pressure, the influences of overcharge current and battery capacity on ignition position, ignition time and flame structure to obtain the ignition mechanism and flame spreading mechanism of lithium-ion batteries. This proposal aims at controlling the behaviors of explosive and combustion of batteries under extreme conditions, and providing some new ideas for the prevention and emergency treatment of safety accidents of lithium-ion batteries.

锂离子电池能量密度高、循环寿命长、环境友好，市场规模和应用领域不断扩大。频繁发 生的安全事故使其安全问题越来越突出。空气冲击波和可燃流体燃烧是安全事故的两个主要灾 害效应。本课题拟围绕空气冲击波和燃烧火焰形成及演变关键科学问题，从锂离子电池组件反 应历程出发，采用试验与数值模拟相结合的方法，研究过充意外激源作用下锂离子电池爆炸空 气冲击波与可燃流体燃烧火焰在时间和空间上的耦合行为；研究电池组件结构-性能-荷电状态 的关联性，获得电池失效的关键步骤；建立耦合过充电流的三维电热模型，掌握电池本体释热 规律；探索电池容量和过充电流对可燃流体溢出特征参数的影响规律，获得空气冲击波压力演 变规律；探索过充电流和电池容量对可燃流体着火位置、着火时间及火焰结构的影响规律，揭 示电池着火机理和燃烧火焰扩展机制，实现电池在极端条件下发生爆炸燃烧行为的过程调控， 为锂离子电池安全事故的预防和应急处理提供新理论、新思路和新方法。