Fabrication of a microcapsule extinguishing agent with a core–shell structure for lithium-ion battery fire safety

Abstract

Safety issues limit the large-scale application of lithium-ion batteries. Here, a new type of N–H-microcapsule fire extinguishing agent with a core–shell structure is prepared by using melamine-urea-formaldehyde resin as the shell material, and perfluoro(2-methyl-3-pentanone) and heptafluorocyclopentane as the core material. Through the test of cooling and extinguishing performance, the optimal ratio of the compound extinguishing agent is 1 : 1, which can extinguish open fire in 8 s. The microencapsulated fire extinguishing agent with a diameter of 60–80 μm is pre-stored on the outer surface of the aluminum plastic film of lithium-ion batteries to form a kind of “protective clothing”, and the shell material will crack and releases the wrapped fire extinguishing agent when lithium-ion batteries reach 120 °C due to thermal runaway, so as to inhibit the spread of fire, cooling from 800 °C to 30 °C in 10 s and inhibit the reburning of lithium-ion batteries. This work changed the liquid fire extinguishing agent into solid microcapsules, which not only proposes a new method and strategy to solve the safety problem of lithium-ion batteries, but also provides useful information for guiding the application of lithium-ion batteries.