Novelty method based on thermal trigger mechanism for high energy density lithium-ion battery safety

Thermal runaway is the most serious issue for high energy density lithium-ion batteries. Adding flame retardants to electrolytes is a general way to improve safety of lithium-ion batteries. However, the addition of flame retardants will give rise to adverse effects on the electrochemical performance of batteries, especially phosphate ester flame retardants decompose on the surface of the negative electrode. This research innovatively outlines a heat-triggered addition method of flame retardants using the polypropylene film (PP film) package. Only under abusive circumstances can the flame retardants be released and have a profound effect. The feasibility of this addition method is verified by the battery thermal safety testing. This ingenious addition method not only avoids the negative effects of flame retardants on battery performance, but also provides a new way to prevent thermal runaway of batteries.