Preparation of a novel environmental-friendly lithium-ion battery fire suppression microcapsule and its fire extinguishing mechanism in coordination with ABC dry powder

Lithium-ion battery fires are one of the main bottlenecks hindering the industrialization development of lithium-ion batteries. The existing fire extinguishing materials can not completely solve the problems of lithium-ion battery cooling, reignition, pollution and so on. Therefore, it is imperative to develop efficient and environmentally friendly fire extinguishing materials. In this paper, environmentally friendly CTS-SA@F7A-Novec 1230 microcapsule fire extinguishing agent with good flame retardant properties was prepared by coating heptafluorocyclopentane (F7A) and perfluorohexanone (Novec 1230) fire-extinguishing materials by the complex coalescence method using chitosan (CTS) and sodium alginate (SA) as the shell material, and the fire-extinguishing effects of the three methods, namely, N2+ABC dry powder + microcapsule (NAM), N2+ABC dry powder (NA), and N2(N), were comparatively analyzed. The research results indicate that, CTS-SA@F7A-Novec 1230 microcapsules were well formed and had excellent thermal stability; The peak heat release rate (PHRR) of CTS-SA@F7A-Novec 1230 microcapsules decreased by 22.56 w/g after the addition of CTS-SA@F7A-Novec 1230 microcapsules to the composite battery materials, and the temperature TPHRR corresponding to PHRR increased by 18.09 °C accordingly, which resulted in a good flame retardant property of the materials; The cell cooling effect was ranked as NAM > NA > N, and the maximum cell surface temperatures under these three methods were reduced by 10.34%, 17.30% and 18.68%, respectively, compared with the thermal runaway experimental data; The fire extinguishing effectiveness was ranked as NAM > NA > N. The maximum flame temperature was reduced by 52.10%, 40.53%, and 23.95%, and the flame extinguishing time was shortened by 71.02%, 64.12%, and 22.48%, respectively, with these three methods compared to the thermal runaway flame data. Based on this, the three-phase synergistic extinguishing mechanism of gas, liquid and solid under the NAM method is revealed, which provides an important reference for the design of extinguishing agents and extinguishing methods for lithium-ion batteries.