Patent ID: 7670717

Claim:
A combined electrode plate for a spirally-wound electrode group for a non-aqueous secondary battery comprising a current collector, an active material layer carried on said current collector and a multi-layer porous membrane carried on said active material layer, wherein said multi-layer porous membrane comprises a first porous membrane and a second porous membrane, said first porous membrane comprises metal oxide particles and a first binder, said second porous membrane comprises resin particles and a second binder, said multi-layer porous membrane has a thickness of 15 to 25 μm, said first porous membrane has a thickness of 2 to 15 μm, said second porous membrane has a thickness of 2 to 15 μm, primary particles of said metal oxide particles have an average particle size of 0.1 to 1 μm, secondary particles of said metal oxide particles have an average particle size of 0.3 to 3 μm, and said secondary particles comprise a cluster having an indefinite shape comprising a plurality of primary particles bonded together.