A Comparative Study On The Effect Of Typical Clean Extinguishing Agents On Suppressing Lithium-ion Battery Fires

Currently,the frequent fire incidents of lithium-ion batteries in the process of civil aviation transportation have seriously affected flight safety.The fire prevention and control technology of lithium-ion batteries has become a major practical problem that needs to be solved urgently.However,the clean extinguishing agents that are efficient for suppressing battery fires,are still being selected.Therefore,on the basis of the fire risk of lithium-ion batteries,the selection range of fire extinguishing agent is expanded in tis study.A variety of clean fire extinguishing agents are designed to proceed the test of suppression battery fire,The optimal fire extinguishing agent is got through comparison.This study provides experimental support for the selection of fire extinguishing agents in practical applications.In order to investigate the effect and efficiency of fire extinguishing agents on suppressing the lithium-ion battery fire.In the confined space,the 14 Ah Li Fe PO₄ lithium battery was used as the research object.It was heated to trigger the combustion by an electric heating plate.The fire extinguishing agents were released at a special time node.First of all,three new clean fire extinguishing agents were selected in this work,including water mist,2-BTP（2-Bromo-3,3,3-Trifluoropropene）and AVD fire extinguishing agent（Aqueous Vermiculite Dispersion）.Three release pressures（0.3,0.6 and 1.0 MPa）and three used doses（100,200 and 300 m L）were designed to investigate the influence of releasing pressure and dosage on the inhibition of temperature rise.The optimal release pressure and used dose were obtained by comparison.Secondly,the optimal state of fire extinguishing agents was chosen to carry out the suppression battery fire experiment,and several parameters were selected to compare the extinguishing efficiency of three fire extinguishing agents and get the optimal agent.Finally,the specialist-scored method was used to determine the weight value of each evaluation index.Several evaluation indexes were selected and the TOPSIS evaluation method（Technique for Order Preference by Similarity to Ideal Solution）was used to evaluate the comprehensive performance of agents and get the optimal scheme.The results show that the Li Fe PO₄ lithium battery fire can be effectively extinguished after the release of three fire extinguishing agents,but there were differences in the efficiency of suppression fire.The fire-fighting efficiency of water mist was the highest,and the fire-extinguishing time was about 11 s.At the same time,compared with the control group,the peak surface temperature decreased significantly with a range of about 100-200℃after applying the agents.The suppression temperature rise of fire extinguishing agent was positively correlated with pressure release and dosage.Several key parameters were selected to compare the extinguishing efficiency of the agents.It was found that the water mist extinguishing efficiency was the highest,the second best was 2-BTP extinguishing agent and last come AVD extinguishing agent.The main mechanism of water mist was physical cooling and dilute oxygen asphyxiation.2-BTP fire extinguishing agent reduced the concentration of free radicals by the free radical catalytic reforming cycle.The AVD extinguishing agent mainly extinguished the battery fire through the synergistic action of endothermic cooling,oxygen isolation and combustible isolation.The TOPSIS compreshensive evaluation method was improved by the triangle fuzzy number.The four first-level indexes and thirteen second-level indexes were chosen.The TOPSIS evaluation method was used to evaluate the comprehensive performance of the three fire extinguishing agents.Water mist showed the best performance under the evaluation system set up in this study,follows by AVD fire extinguishing agent and 2-BTP fire extinguishing agent.