Research On The Effectiveness Of Fire Detection Tube Fire Extinguishing System To Suppress Thermal Runaway Of Lithium Ion Batteries

Due to its high energy density,good cycling performance,and high operating voltage,lithium-ion batteries are widely used in fields such as mobile electronic devices,electric vehicles,and energy storage stations.However,in recent years,safety accidents caused by lithium-ion batteries have been common,posing a serious threat to people’s lives,health,and property.At present,the suppression technology for thermal runaway hazards of lithium-ion batteries is still in the selection stage.Therefore,in order to effectively weaken the harm of thermal runaway in lithium-ion batteries,it is urgent to carry out research on thermal runaway hazard suppression technology.Based on the characteristics and practical application requirements of thermal runaway hazards in lithium-ion batteries,a fire detection tube type thermal runaway hazard suppression system has been independently designed.The characteristic of this system is that the fire detection tube is used as a sensing element for battery thermal runaway,which can automatically trigger when the battery thermal runaway occurs,and can also transport the suppression medium at a fixed point to the battery that generates thermal runaway.Due to the advantages of cleanliness,affordability,and good cooling effect,water is currently a hot material in the research of thermal runaway hazard suppression for lithium-ion batteries.Therefore,water is chosen as the suppression medium for the fire detection tube type thermal runaway hazard suppression system.On the basis of the self-developed thermal runaway hazard suppression system,this article conducted a series of thermal runaway hazard suppression simulation experiments,revealing the disaster suppression mechanism of the fire detection tube type thermal runaway hazard suppression system,and exploring the relevant factors affecting the system’s disaster suppression ability.The main tasks are as follows:（1）We have established an open space lithium-ion battery thermal runaway hazard suppression experimental platform and studied the effects of suppression medium types,medium dosages,and driving pressures on the disaster suppression ability of a fire detection tube type thermal runaway hazard suppression system in an open space environment.Research has found that under the conditions of consistent dosage and driving pressure,the fire extinguishing and cooling ability of water is significantly better than that of C₆F₁₂O;The fire extinguishing and cooling capacity of the system is positively correlated with water consumption.Under a driving pressure of 1MPa,25 m L and 50 m L doses of water cannot suppress the combustion of thermal runaway gas.With the increase of water consumption,the battery no longer experiences severe combustion after thermal runaway,and the maximum surface temperature and duration of high temperature of the battery are greatly reduced;Under the condition of restraining the water consumption of the medium to 100 m L,a pressure of 0.5 MPa failed to ensure timely response of the system,resulting in an open flame in the battery after thermal runaway;When the driving pressure gradually increases,the system can respond in a timely manner,but the released droplets show obvious sputtering phenomenon,which has a negative impact on the cooling efficiency of the system.When the driving pressure is 1 MPa,the cooling performance of the system is the best.（2）We have established an experimental platform for the suppression of thermal runaway hazards of lithium-ion batteries in enclosed spaces,conducted thermal runaway experiments on individual lithium-ion batteries in enclosed spaces,and studied the effects of medium dosage and driving pressure on the disaster suppression ability of a fire detection tube type thermal runaway hazard suppression system.Research has found that there is a risk of gas explosion when lithium-ion batteries experience thermal runaway in enclosed spaces,and the intensity of gas explosion after thermal runaway is positively correlated with the battery’s state of charge;The ability of the system to suppress gas explosions is positively correlated with water consumption and driving pressure.At a driving pressure of 1 MPa and a water consumption of 100 m L,the system can completely suppress the gas explosion caused by thermal runaway of a 100%SOC single lithium-ion battery.When the water consumption is 100 m L and the driving pressure is 0.5 MPa,it cannot suppress the thermal runaway gas explosion.As the driving pressure increases,the gas explosion intensity decreases until the thermal runaway gas does not explode.（3）On the basis of research on the suppression of thermal runaway hazards in individual lithium-ion batteries,further research was conducted on the thermal runaway hazard characteristics of lithium-ion battery modules and the ability of the fire detection tube type thermal runaway hazard suppression system to suppress thermal runaway propagation.Research has found that the thermal runaway of one battery within a battery module can lead to the subsequent thermal runaway of other batteries,and the batteries within the battery module will exhibit more complex flame behavior during the thermal runaway process;Equipping a single battery with 100 m L of water can prevent the thermal runaway propagation of battery packs arranged in ways 1×3 and 3×3,while under the same conditions,C₆F₁₂O has a poor ability to prevent thermal runaway propagation and cannot completely prevent the thermal runaway propagation of 3×3 battery modules.