锂离子电池用聚烯烃复合隔膜材质及薄膜厚度的检测  

Measurement for the Material and Film Thickness of Polyolefin Composite Diaphragm Used in Lithium Ion Battery

作　　者：付雪涛[1] 张军华 曹可慰 颜旺 王香[1] 吴怡然 FU Xue-tao;ZHANG Jun-hua;CAO Ke-wei;YAN Wang;WANG Xiang;WU Yi-ran(China Electronics Standardization Institute,Beijing 100176,China)

机构地区：[1]中国电子技术标准化研究院,北京100176

出　　处：《塑料工业》2021年第9期126-129,139,共5页China Plastics Industry

摘　　要：复合隔膜的材料种类及结构尺寸已成为了产品质量检验、锂离子电池失效分析中关注的对象,通过对聚丙烯/聚乙烯/聚丙烯(PP/PE/PP)复合隔膜进行叠折、压实、切割后获得了规整、无变形的横截面,采用偏光显微镜、激光共聚焦显微拉曼光谱仪对复合隔膜的横截面进行了分析,鉴别了隔膜的类型(单层或多层),并测定了每层薄膜的厚度、材质。结果显示,PP、PE、PP薄膜厚度分别为7.71、5.34、6.68μm,隔膜总厚度为19.73μm,测量值与理论真值的偏差不大于2%,且各薄膜的材质可以通过激光共聚焦显微拉曼光谱实现鉴别。采用同步热分析仪对复合隔膜的熔融温度及热焓进行了测定,结果显示聚乙烯的熔融温度为134℃,热焓大约为179~187 J/g。结合聚乙烯熔融温度与结晶度的递增关系或热焓与结晶度的线性关系,从而进一步明确了复合隔膜中聚乙烯的密度类型。The material and structure size of composite diaphragm had become the focus in product quality inspection and failure analysis of lithium ion battery.The polypropylene/polyethylene/polypropylene(PP/PE/PP)composite diaphragm was folded,compacted and cut to obtain a regular,non-deformation cross section.The cross section of the composite diaphragm was analyzed by polarizing microscope and laser confocal microscopic Raman spectrometer,the type of diaphragm(single layer diaphragm or multilayer diaphragm)was identified,and the thickness and material of each film were determined.The result shows that the thickness of PP,PE and PP film is 7.71μm,5.34μm and 6.68μm respectively,the total thickness of diaphragm is 19.73μm,the deviation between the measured value and the theoretical truth value is no more than 2%,and the material of each film can be identified by laser confocal microscopy Raman spectroscopy.The melting temperature and enthalpy of the composite diaphragm were measured by synchronous thermal analyzer,the result shows that the melting temperature of polyethylene is 134℃,the enthalpy of polyethylene is about 179~187 J/g.According to the increasing relationship between melting temperature and crystallinity or the linear relationship between enthalpy and crystallinity of polyethylene,the density type of polyethylene in the composite diaphragm was further determined.

关 键 词：聚丙烯 聚乙烯 复合隔膜 厚度 材质 

分 类 号：TQ325.1[化学工程—合成树脂塑料工业]