| 摘要 |
PURPOSE:To retard generation ot dendritic lithium and to increase charge- discharge performance and safety by using a microporous film-like separator whose porosity and micropore opening areas are specified. CONSTITUTION:A separator 3 is formed by cutting a sheet made of polypropylene and having three-dimensional micropore networks in the shape of belt whose width is wider than those ot positive and negative plates. The separator is interposed between positive and negative plates, and they are spirally wound to form an electrode body. The separator is a microporous film, and has a porosity of 20-60%, and a pore opening area of 1.0X10<-3>-5.0X10<-3>mum<2>. By this separator, generation of dendritic lithium is retarded, and even if internal short circuit arises, the positive and negative plates are separately covered by heat shrinkage of the separator, and hiring caused by melting of metallic lithium generated by short circuit heat is prevented. |
