高比能NCM动力电池热失控扩展安全阻隔技术

Research on thermal runaway expansion barrier technology of NCM power battery

为有效控制高能量密度锂离子电池(LIBs)热失控扩展,提出一种复合阻隔技术。以软包镍钴锰(NCM) 811型(NCM811)电池为研究对象,分析现有锂离子电池热失控火灾防控方法及NCM811电池热失控特性,通过加热方式进行电池热失控特性试验,以确定表面温度和热失控触发时间之间的影响关系;通过以气凝胶、石棉、岩棉为代表的不同微结构尺寸材料的热阻隔试验,确定微结构尺寸与热阻隔特性的关系;通过不同厚度、层数的热阻隔试验,研究不同阻隔方案的热阻隔特性。研究表明:在进行毫米厚度级别的热阻隔时,阻隔板材料微结构尺寸越小(小于空气分子平均自由程70 nm),阻隔板越薄、层数越多,热阻隔效果越好。

In order to effectively control thermal runaway expansion of high energy density lithium ion batteries( LIBs),a composite barrier technology was proposed. With soft NCM811 battery as research object,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. Then, thermal insulation tests for materials of different microstructures and sizes,represented by aerogels,asbestos and rock wool,were conducted to determine relationship between microstructure size and thermal barrier characteristics. Finally, 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),the thinner it is,and the more layers and better thermal barrier effect it has.