OXYGEN-PERMEABLE COMPOSITE MEMBRANE AND BATTERY USING THE SAME

摘要

PURPOSE:To provide excellent practicality within the wide range over the high- low load of a battery, excellent liquid leakage resistance and long-term storage properties by mainly constituting an oxygen-permeable composite membrane of a porous polymeric membrane coated with a mixture of a solvent-soluble fluoroplastic and fluorinated graphite with a particle size of 10mum or less. CONSTITUTION:For example, in a button battery, an oxygen permeable composite membrane 11 selectively introducing the oxygen gas in the atmosphere into the battery and preventing the pernetration of the steam and carbon dioxide in the atmosphere into the battery over a long period of time is interposed between a water repelling membrane 2 made of polytetrafluoroethylene blocking an electrolyte 7 constituting a cathode and the porous membrane 4 supporting an oxygen electrode 1 and permitting the diffusion of air. The oxygen-permeable composite membrane can be obtained by a method wherein fluorinated graphite with a particle size of 10mum or less is added to solvent-soluble fluoroplastic to be sufficiently dispersed therein under stirring to be applied to a fluoroplastic porous membrane being a support membrane and the solvent in the formed layer is naturally evaporated at room temp.