Research On Fire-Extinguishing Agents For Lithium-Ion Batteries Fire

Lithium-ion batteries are prone to fire or even explode due to overcharge,short circuit,overheating,puncture or collision.In order to reduce the risk of lithium battery fire,it is urgent to study the fire extinguishing agent of lithium ion battery.The combustion situation of lithium-ion batteries is very complex,and rapid cooling is the key to extinguishing the fire.Water has a high specific heat capacity,and water-based fire extinguishing agents can inhibit fire and runaway battery heat propagation.The aqueous film foam extinguishing agent is composed of fluorocarbon surfactant,which can be used in combination with hydrocarbon surfactant.It can quickly film on the surface of combustible materials,play the dual role of cooling and oxygen isolation,and has the advantages of high extinguishing efficiency and short time,and can prevent reignition.However,perfluorooctane sulfonate and its derivatives are the main active components of traditional aqueous film foam extinguishing agents,which are difficult to degrade and toxic to organisms.The fire extinguishing agent of lithium ion battery fire must be environmentally friendly and safe,and it is necessary to develop a new water-based fire extinguishing agent.In this paper,according to the fire characteristics of lithium ion battery combustion,the biodegradable perfluorohexyl（C6 type）fluorocarbon surfactant was used as the basic active ingredient,and the best hydrocarbon surfactant was selected as the auxiliary active ingredient to compose the complex system with two parameters of surface tension and foaming ratio.After screening,the surface tension of the compound solution composed of perfluorohexyl fluorocarbons surfactant VF-9129 and sodium dodecyl sulfate is the lowest,which is 14.44 m N·m^-1.It can quickly spread and fully cover the surface of combustible materials and put out flames.At the same time,blowing agent,antifreeze agent,cosolvent and other components are added to the system to improve the physical and chemical properties of the system,which can quickly extingule the lithium ion battery fire and prevent the reignition effect.In this paper,according to the relevant standards of the national standard"foam extinguishing agent"（GB15308-2006）,test the foaming multiple of the fire extinguishing liquid is 8.3,the spreading time is 0.3 s,the corrosion rate is 8.639,the p H value is 9.29,the frost resistance is excellent,the test results show that its performance is in line with the requirements of the relevant national standards.This extinguishing fluid was applied to the fire of single lithium ion battery,and the combustion experiment was carried out on the independently designed and built fire extinguishing platform.After the lithium-ion battery is burned,the temperature changes during the combustion process are collected synchronously after the lithium-ion battery fire extinguishing fluid is ejected at an appropriate time.The results show that the configured lithium ion battery fire extinguishing fluid can extinguish 25 Ah lithium ion battery flame within 10 s,and will not reignite.