拉伸外场作用下热定型工艺对湿法隔膜微观结构及性能影响关系研究  

The Influence of Heat Setting Process on the Microstructure and Performance of Wet-process Separator under the Tensile External Field

作　　者：万彩霞 王月勤 胡玉涛 周世蛟 宋红芹 许寒飞 李良彬[1] Cai-xia Wan;Yue-qin Wang;Yu-tao Hu;Shi-jiao Zhou;Hong-qin Song;Han-fei Xu;Liang-bin Li(National Synchrotron Radiation Laboratory,University of Science and Technology of China,Hefei 230026;Lucky Film Co.,Ltd,Baoding 071054)

机构地区：[1]中国科学技术大学国家同步辐射实验室,合肥230029 [2]乐凯胶片股份有限公司,保定071054

出　　处：《高分子学报》2022年第3期245-253,共9页Acta Polymerica Sinica

基　　金：国家重点研发计划项目(项目号2020YFA0405800);国家自然科学基金(基金号51790503)资助。

摘　　要：在湿法隔膜制备过程中,热定型工艺与常规热定型工艺有所不同,在高温处理同时还需要对隔膜进行拉伸回缩,即湿法隔膜在热定型过程中存在拉伸外场和温度场耦合作用.本文通过设计不同拉伸比与回缩比,研究了热定型工艺中拉伸外场(拉伸比、回缩比)对隔膜微观结构及宏观热收缩性能的影响关系.结果发现,小的拉伸比(≤1.3)仅作用于聚乙烯的无定型区,随拉伸比增大,聚乙烯晶体开始被拉伸破坏,导致结晶度和晶粒尺寸均减小.同时随拉伸比增大,湿法隔膜孔径呈增大趋势,而回缩比增大同样会使得隔膜孔径增大,在回缩过程中隔膜内部会发生纤维融合和孔隙增大.此外,拉伸比和回缩比增大有利于隔膜内应力的释放,使得隔膜TD热收缩率明显减小.In the producing process of wet-process separator,the heat setting process is different from the conventional one,because in addition to the high temperature treatment,the separator also needs to be stretched and retracted.That is,the coupling effect of stretching external field and temperature field act on the wet separator during the heat setting process.In this study,by designing different draw ratios and retraction ratios,the influence of the external stretching field(draw ratio,retraction ratio)on the microstructure and macro thermal shrinkage properties of the separators during the heat setting process is studied.It was found that a small draw ratio(≤1.3)only acts on the amorphous region of polyethylene.As the draw ratio increases,the polyethylene crystals begin to be stretched and destroyed,resulting in the decrease of crystallinity and crystal size.At the same time,increasing draw ratio could enlarge the pore diameter of the wet separator.While the pore diameter of the separator also increases with the retraction ratio,indicating that the fiber fusion and pore enlargement occur during the retraction process.In addition,the increase of the draw ratio and the retraction ratio is beneficial to the release of the internal stress in separator,so that the TD thermal shrinkage of the separator is significantly reduced.

关 键 词：湿法隔膜 内应力 热定型 孔径 热收缩 

分 类 号：TM912[电气工程—电力电子与电力传动] TB383.2[一般工业技术—材料科学与工程]