磷酸铁锂电池火灾危险性

Fire risk of lithium iron phosphate battery

由于稳定性好、可靠性高等优点,近年来磷酸铁锂电池在储能和变电系统中得到大量应用。为研究大容量磷酸铁锂电池的火灾危险性,通过自主设计的锂离子电池火灾测试平台,开展了228 A·h磷酸铁锂电池的热滥用测试,系统研究了该大型电池的燃烧过程及产热规律,对比分析了不同荷电状态(SOC)下目标电池的火灾特性。结果表明电池的燃烧行为可大致分为初次射流火、稳定燃烧、多次射流火以及火焰熄灭等阶段;燃烧行为会进一步加速电池温度的上升,而对于荷电状态较高的电池,内短路是造成其温度迅速跃升的关键因素;荷电状态较高的电池燃烧过程更加剧烈,具体表现为电池温度、热释放速率(HRR)、燃烧热将会更高,相应电池的燃烧时间也将更加短暂。此外,高温会造成电池电压的微量衰减,但是电池的安全泄压时间往往早于电压跳水时间。本研究结果旨在为锂离子电池系统在储能、变电等领域的安全设计及火灾防控技术提供理论和技术支撑。

In recent years,the lithium iron phosphate battery(LIB)has been widely used in energy storage and power transformation systems because of its advantages of good stability and high reliability.With the purpose of investigating the fire risk of LIB with large capacity,the thermal abuse test of the 228 A·h LIB is conducted through the fire test platform.The combustion process and heat generation law of the LIB were systematically studied,as well the fire characteristics of the battery with different state of charge(SOCs)were compared and analyzed.The result indicates that the combustion behavior of the battery can be roughly divided into several stages:the first jet flame,stable combustion,multiple jet lame and extinguishing stages.Further,the combustion behavior will further accelerate the temperature rise,and the internal short circuit for the battery with higher SOC will cause the rapid temperature rise.The battery with high SOC shows intense combustion behavior while the corresponding burning time will be shorter,which is specifically reflected in the higher temperature,heat release rate(HRR)and heat of combustion.In addition,the venting time is earlier than the voltage drops although the high temperature will result in the slight attenuation of the battery.The results in this work can provide theoretical and technical support for the safety design and fire prevention and control technology of lithium-ion battery systems in the fields of energy storage and transformer substation system.