Thermal runaway (TR) behavior of 38 Ah lithium-ion batteries with various states of charge (SOC) is experimentally investigated in this work using extended volume plus accelerating rate calorimeter (EV+ ARC). Some of the critical kinetic parameters, such as onset exothermic temperature (T_onset), temperature of TR (T_TR), and maximum temperature (T_max), can be obtained to characterize the risks of TR event. The impact of SOC on thermal stability of the battery is researched. It is found that the higher the SOC state, the lower the battery safety. Thermal features of both the cathode and anode, as well as the materials, are also investigated. The morphology and the structure change of the materials are characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). Finally, a general theory is proposed and detailed reactions are summarized in this work. The thermal runaway follows a mechanism of chain reactions, during which the decomposition reactions of the battery component materials occur one after another.

在这项工作中，使用扩展体积加加速量热仪（EV + ARC），通过实验研究了38 Ah具有不同充电状态（SOC）的锂离子电池的热失控（TR）行为。一些关键的动力学参数，例如起始放热温度（T _onset），TR温度（T _TR）和最高温度（T _max），可以表征TR事件的风险。研究了SOC对电池热稳定性的影响。发现SOC状态越高，电池安全性越低。还研究了阴极和阳极以及材料的热特性。通过扫描电子显微镜（SEM）和X射线衍射（XRD）表征材料的形貌和结构变化。最后，提出了一个一般的理论，并在这项工作中总结了详细的反应。热失控遵循链式反应的机理，在此过程中，电池组件材料的分解反应一个接一个地发生。