基于电化学机理模型的锂离子电池早期内短路电热特征研究

锂离子电池的内短路故障是诱发其热失控的主要原因之一，早期内短路特征研究能够为电池管理系统的故障诊断和安全预警提供支撑，对提高电动汽车的安全性具有重要意义。构建了锂离子电池内短路电化学机理模型，实现了不同内短路阻值下的锂枝晶内短路故障模拟。结果表明，由锂枝晶导致的电池内短路产热98%以上来源于正负极产生的焦耳热，早期内短路过程中正负极集流体表面的温升小于1.5 K，不显著的外部热特征无法用于早期内短路故障诊断。与正常电池相比，内短路故障将使得电池充电速度变慢，放电速度变快，端电压异常下降，上述电特征可以为构建早期内短路故障诊断方法提供依据。

Electrical and thermal characteristics of early stage internal short circuit of lithium-ion batteries based on electrochemical mechanism model

Internal short circuit (ISC) fault is one of the major causes of thermal runaway in lithium-ion battery. Study on early stage ISC characteristics can provide support for fault diagnosis and safety warning in battery management systems, which is of great significance to improve the safety of electric vehicles. An electrochemical ISC model for lithium-ion battery was constructed to simulate the ISC fault caused by lithium dendrites with different ISC resistance. The results show that more than 98% of the generated heat during the process of ISC caused by lithium dendrites in the battery comes from joule heat generated by positive and negative electrodes. The temperature rise on the current collector surface of positive and negative electrodes is less than 1.5 K in the early stage ISC, so the non-significant external thermal characteristics can not be used for fault diagnosis of early stage ISC. Compared to normal batteries, the ISC fault will make the battery charge slower, discharge faster and the terminal voltage abnormally drop. The above electrical characteristics can provide the basis for the establishment of early stage ISC fault diagnosis methods.