Safety issue is very important for the lithium ion battery used in electric vehicle or other applications. This paper probes the heat sources in the thermal runaway processes of lithium ion batteries composed of different chemistries using accelerating rate calorimetry (ARC) and differential scanning calorimetry (DSC). The adiabatic thermal runaway features for the 4 types of commercial lithium ion batteries are tested using ARC, whereas the reaction characteristics of the component materials, including the cathode, the anode and the separator, inside the 4 types of batteries are measured using DSC. The peaks and valleys of the critical component reactions measured by DSC can match the fluctuations in the temperature rise rate measured by ARC, therefore the relevance between the DSC curves and the ARC curves is utilized to probe the heat source in the thermal runaway process and reveal the thermal runaway mechanisms. The results and analysis indicate that internal short circuit is not the only way to thermal runaway, but can lead to extra electrical heat, which is comparable with the heat released by chemical reactions. The analytical approach of the thermal runaway mechanisms in this paper can guide the safety design of commercial lithium ion batteries.

对于电动汽车或其他应用中使用的锂离子电池，安全性问题非常重要。本文利用加速量热法（ARC）和差示扫描量热法（DSC）探究了由不同化学组成的锂离子电池热失控过程中的热源。使用ARC测试了4种商用锂离子电池的绝热热失控特征，而使用DSC测量了4种电池内部的组成材料（包括阴极，阳极和隔板）的反应特性。DSC测量的关键组分反应的峰和谷可以匹配ARC测量的升温速率的波动，因此，利用DSC曲线和ARC曲线之间的相关性来探测热失控过程中的热源并揭示热失控机理。结果和分析表明，内部短路不是导致热失控的唯一方法，而是会导致额外的电热，这与化学反应释放的热量相当。本文对热失控机理的分析方法可以指导商业锂离子电池的安全设计。