含添加剂细水雾抑制三元锂离子电池火灾试验研究

Experimental study on fire suppression of ternary lithium-ion battery by water mist with additive

通过自主搭建的锂离子电池燃烧及灭火平台,以三元镍钴锰酸锂电池为研究对象,开展了含添加剂细水雾抑制三元锂离子电池火灾试验,从溶液表面张力、电池最高温度以及降温速率等方面综合分析溶液灭火机理及效果。试验中选择热滥用方式,采用加热炉加热,使三元锂离子电池发生热失控燃烧,采用高清摄像机记录全过程。选取十二烷基苯磺酸钠、十二烷基硫酸钠、氯化钠、氯化钾、磷酸二氢铵、碳酰胺6种添加剂进行单一及复配溶液细水雾灭火试验。测量每种溶液的表面张力,分析其随溶液浓度的变化情况以及对灭火性能的影响,发现表面活性剂可使溶液的表面张力降低,提高细水雾雾化效果。而表面活性剂趋于饱和后,溶液的表面张力则基本保持稳定。用K型热电偶测量三元锂离子电池热失控及细水雾灭火过程中的温度,将测得的电池最高温度、降温速率等特征参数进行对比分析,结果表明,相比于纯水细水雾,含添加剂细水雾在雾化效果、稀释氧气以及阻断燃烧反应链等方面均有较大提升,且电池未发生复燃。十二烷基苯磺酸钠、十二烷基硫酸钠、氯化钠、氯化钾、磷酸二氢铵、碳酰胺单一添加剂细水雾抑制三元锂离子电池火灾的最佳质量分数分别为1.5%、1%、8%、10%、10%、0.3%。在单一添加剂最佳灭火浓度的基础上进行复配,发现氯化钾与磷酸二氢铵两种添加剂单一灭火效果优于二者复配溶液,其间灭火作用存在相互抵消的现象。表面活性剂、碱金属盐与受热易分解物质3种添加剂共同作用时可以有效提高灭火效率,其中,十二烷基苯磺酸钠(1.5%)、氯化钾(10%)与磷酸二氢铵(10%)的复配溶液细水雾灭火效果最优。该复配溶液通过降低溶液的表面张力、减小细水雾雾滴粒径以及电离出金属离子与燃烧链中的自由基结合等多种机理协同发挥作用,吸收大量热量,得到较好的灭火效果。对含不同添加剂细水雾抑制三元锂离子电池热失控火灾展开了相关试验,在今后的研究中,可以选择更多不同类型以及浓度的添加剂进行复配试验,从高效、环保的角度充分考虑各种灭火剂的优缺点,为锂离子电池消防安全技术提供支撑。

Through self-built lithium-ion battery combustion and fire extinguishing platform, taking the ternary lithium nickel cobalt manganese oxide battery as the research object, the fire test of ternary lithium-ion battery by water mist with additive was carried out, the mechanism and effect of solution fire extinguishing were analyzed comprehensively from the aspects of solution surface tension, battery maximum temperature and cooling rate, etc. In the test, the heat abuse method was selected, and a heating furnace was used to heat the ternary lithiumion battery to cause thermal runaway combustion, and a highdefinition camera recorded the whole process. Six kinds of additives including sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium chloride, potassium chloride, ammonium dihydrogen phosphate and carbonamide were selected for single and compound solution water mist fire extinguishing test. The surface tension of each solution was measured, and its change with the concentration of the solution and its influence on the fire extinguishing performance were analyzed. It was found that the surface active agent could reduce the surface tension of the solution, thereby improving the atomization effect of water mist.When the surfactant tends to be saturated, the surface tension of the solution remains basically stable. A K-type thermocouple was used to measure the temperature during the thermal runaway of the ternary lithium-ion battery and the water mist fire extinguishing process, and the measured characteristic parameters such as the highest temperature and cooling rate of the battery were compared and analyzed. The result shows that, compared with pure water mist, the fire extinguishing performance of the additive-containing water mist is improved greatly in atomization effect, diluted oxygen concentration, and blocking the combustion reaction chain, and the battery does not reignite.The best mass fraction of single additive water mist with sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium chloride, potassium chloride, ammonium dihydrogen phosphate, and carbamide to suppress the fire of ternary lithium-ion battery is 1.5%, 1%, 8%, 10%, 10%, 0.3% respectively. Compounding on this basis, it was found that the single extinguishing effect of potassium chloride and ammonium dihydrogen phosphate was better than the combined solution, the fire extinguishing effects canceled each other out. Coordination of surfactants, alkali metal salts and three additives that are easily decomposed by heat can improve the fire extinguishing efficiency effectively, the mixed solution of sodium dodecyl benzene sulfonate(1.5%), potassium chloride(10%) and ammonium dihydrogen phosphate(10%) had the best fire-extinguishing effect. The compound solution works synergistically through various mechanisms such as reducing the surface tension of the solution, reducing the particle size of fine water mist droplets, and combining ionized metal ions with free radicals in the combustion chain, absorbing a large amount of heat, thereby obtaining better fire extinguishing effect.The article carried out relevant experiments on the suppression of thermal runaway fires in ternary lithium-ion batteries with fine water mist containing different additives. In future research, more additives of different types and concentrations can be selected for compounding experiments considering fully from the perspective of high efficiency and environmental protection, and the advantages and disadvantages of various fire extinguishing agents, to provide support for lithium-ion battery fire protection technology.