过热条件下86 Ah磷酸铁锂电池热失控行为研究

Study on Thermal Runaway Behavior of 86 Ah Lithium Iron Phosphate Battery Under Overheat Condition

随着电化学储能项目快速发展,储能用电池的安全性越来越受到社会的关注。为了更好地防控储能用锂离子电池的热失控风险,需对其热失控行为有着清晰的认识。该文基于锂离子电池热失控实验平台,采用过热的方式触发86 Ah磷酸铁锂电池热失控,对其热失控的产热与产气过程进行深入分析。以泄压阀打开与最高温度这两个临界点将热失控过程分为3个阶段。热失控过程中,发现温升速率存在2个峰值,分别对应温度为110℃与225℃,并进一步分析了温升速率存在2个峰值的可能原因。通过傅里叶红外光谱仪(FITR)和氢气探头监测,得到热失控产生气体的实时组分,并详细梳理了各类产气反应。最后,对热失控产生气体在整个热失控过程中进行积分,二氧化碳和氢气是热失控产气的主要成分,两者分别占比30.15%与39.5%。该文研究可为储能电站锂离子电池火灾事故预警提供参考。

With the rapid development of electrochemical energy storage projects,the safety of energy storage battery has attracted more and more attention.In order to prevent and control the thermal runaway risk of lithium-ion battery,it is necessary to clarify the behavior of thermal runaway.Based on the lithium-ion battery thermal runaway experimental platform,overheating is used to trigger the thermal runaway of 86 Ah iron phosphate lithium battery.The process of thermal runaway heat and gas generation is analyzed.The thermal runaway process is divided into three stages by two critical peaks at the pressure relief valve opening and maximum temperature.In the process of thermal runaway,it is found that there are two peaks of temperature rise rate corresponding to 110℃and 225℃,and the possible reasons for the temperature rise rate peaks are further analyzed.Moreover,the online detection of gases measuring is conducted through Fourier Transform Infrared(FTIR)and hydrogen probe.The real time components of the gas produced by thermal runaway are obtained and various gas generation reactions are summarized in detail.Finally,the thermal runaway gases are integrated during the whole thermal runaway process.The results reveal that carbon dioxide and hydrogen are main components in the gas production and account for 30.15%and 39.5%,respectively.The results can provide insight into the early warning of lithium-ion battery fire accident in electrochemical energy storage.