过热影响下大容量锂离子电池火灾发生机制与危险特性研究

Being the carrier of power supply or energy storage, vast quantities of large-capacity lithium-ion batteries are being used in the new energy vehicles and energy storage power station. Fire accidents are apt to occur when the batteries are under the influence of over-heating. This phenomenon is not similar to the thermal runaway of the battery without considering fire. Furthermore, the fire behavior and hazard characteristics of the large-capacity lithium-ion battery is quite different from that of the small one. In this project, experimental research and theoretical analysis will be combined. The thermal-electrical synchronous characteristic parameters and coupling interaction of the large-capacity lithium-ion battery at the critical state of fire will be examined, under the effect of various heat source powers and battery characteristics. The occurrence mechanism and critical criterion of the battery fire will be determined. By analyzing the thermal and smoke hazard characteristics and the multiple eruption behavior of jet fire, relationship of the fire hazard characteristics, the heat source powers and the battery characteristics will be established, and the controlled mechanism of the jet fire will be revealed. This study will deepen understanding and provide reliable basis for fighting decision of the lithium-ion battery fire, and also has realistic significance for protecting the consumers, firefighters and the personal and property safety related with the electric vehicle and energy storage power station.

作为提供动力或储存能量的载体，大容量锂离子电池被大量应用于新能源汽车、储能电站中。电池容易在过热影响下起火，这一事故现象不同于未考虑起火的电池热失控；大容量锂离子电池的火灾行为以及危险特性与小型锂离子电池也有所不同。本项目拟通过实验研究与理论分析，系统研究不同热源功率、电池特征等条件下大容量锂离子电池起火临界状态的热-电同步特征参数及热-电耦合作用关系，揭示电池的起火机制与临界判据；分析着火过程中电池的热、烟气危险特性以及喷射火多次喷发行为，获得电池热、烟气特性参数随热源、电池特征变化规律，揭示电池喷射火动力学特征与多次喷发受控机制。本项目的开展有助于加深对锂离子电池火灾的认识，为大容量锂离子电池火灾消防决策提供可靠依据，对于保护消费者、消防人员、电动交通工具与储能电站相关的人身、财产安全具有现实意义。

锂离子电池目前广泛用于电动汽车、储能等领域，但是由于锂离子电池本身的热稳定性等问题，在过热等热滥用条件下极易引发热失控，进而发生火灾爆炸等严重后果。为此，本项目通过实验、数值模拟和理论分析，主要研究了过热条件下高能量锂离子电池热失控火灾行为及特征，获得了电池着火、发生爆燃的临界热辐射通量、临界温度、产热、烟气成分及变化、喷射火特征参数等，揭示了电池的不同荷电状态对电池起火时间、着火时间、起火临界参数的影响规律，揭示了锂离子电池热失控、起火、爆燃的反应历程。基于开源CFD计算平台Open FOAM，将电化学平衡与传热、能量平衡方程等进行耦合，编译了能够描述锂离子电池热-电特性的求解器，建立了能够准确预测外部加热滥用条件下单体电池热失控发生的产热、电压、电流等参数变化的三维模型。针对主流的圆柱形和方形锂离子电池，分别提出了基于相变材料-翅片的被动热管理和基于相变材料-液冷的主动热管理方案。通过实验和数值模拟方法，对两种热管理方案的具体参数进行了分析，获得了两种热管理方案的最优参数和管理策略，为圆柱形电池和方形电池的热管理提供了新的思路。