Separator for battery, battery and process for preparing the separator

• Main Authors: SHIOTA HISASHI, URUSHIBATA HIROAKI, HAMANO KOUJI, HIROI OSAMU, MURAI MICHIO, ARAGANE JUN, INUZUKA TAKAYUKI, YOSHIDA YASUHIRO, AIHARA SIGERU, TAKEMURA DAIGO
• Format: Patent
• Language: English
• Published: 28.06.2001
• Edition: 7
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRICITY; PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSIONOF CHEMICAL INTO ELECTRICAL ENERGY

Conventional separators had a function that their melting made minute holes inside the separator smaller, leading to cut off of ion conductivity in temperature increase due to unusual conditions such as short circuit. However, there was a problem that, at a temperature higher than a certain degree, not only the minute holes were closed but also the separator itself was melted to cause deformation of the separator such as shrink and generation of holes due to melting and insulation was broken. The present invention has been carried out in order to solve the above problems. The separator for batteries of the present invention comprises a first porous layer (3a) containing a thermoplastic resin as a main component and a second porous layer (3b) laminated on the first porous layer (3a), which has higher heat resistance than that of the first porous layer (3a).