Preparation method of composite diaphragm for lithium ion battery

• Main Authors: AN XUPENG, REN SHUAIJIAN, CHANG LI, YAN WEIXING
• Format: Patent
• Language: Chinese; English
• Published: 05.04.2024
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRICITY; PERFORMING OPERATIONS; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY; PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCESIN A PLASTIC STATE; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL

Aiming at the problem of high thermal shrinkage rate of a polyolefin diaphragm, the invention provides a preparation method of a composite diaphragm for a lithium ion battery, and belongs to the technical field of preparation of diaphragms for lithium ion batteries, the preparation method of the composite diaphragm comprises five steps of melt extrusion, sheet longitudinal stretching, sheet transverse stretching, additive extraction and secondary transverse stretching, wherein a certain amount of silane coupling agent and nano-hydroxyapatite are added into the polyolefin raw material. According to the preparation method disclosed by the invention, polyolefin is taken as a matrix and is combined with nano-hydroxyapatite, and the composite diaphragm with extremely low thermal shrinkage rate and excellent ionic conductivity can be prepared through a two-way stretching process. 本发明针对聚烯烃隔膜热收缩率高的问题，提供一种锂离子电池用复合隔膜的制备方法，属于锂离子电池用隔膜制备技术领域，所述复合隔膜的制备方法包括熔融挤出，片材纵向拉伸，片材横向拉伸，助剂萃取及二次横向拉伸5个步骤，其中在聚烯烃原料中加入了一定量的硅烷偶联剂与纳米羟基磷灰石。本发明