Research on thermal runaway expansion barrier technology of NCM power battery

Abstract

In order to effectively control thermal runaway expansion of high energy density lithium ion batteries (LIBs)ꎬ a composite barrier technology was proposed. With soft NCM811 battery as research objectꎬ existing fire prevention and control method of LIBs was analyzed and relationship between surface temperature and thermal runaway trigger time was determined by studying its thermal runaway characteristics. Thenꎬ thermal insulation tests for materials of different microstructures and sizesꎬ represented by aerogelsꎬ asbestos and rock woolꎬ were conducted to determine relationship between microstructure size and thermal barrier characteristics. Finallyꎬ thermal resistance characteristics of different barrier schemes were studied through thermal isolation tests with different thickness and number of layers. The results show that the smaller microstructure of barrier material is ( less than 70 nm of average free path of air molecules)ꎬ the thinner it isꎬ and the more layers and better thermal barrier effect it has.