US Patent 7670717 Spirally-wound non-aqueous secondary battery and electrode plate used therefor

To provide a non-aqueous secondary battery having a capacity as high as that of a conventional battery using a conventional resin separator and achieving excellent overcharge characteristics and excellent resistance to external short-circuit, a combined electrode plate for a spirally-wound electrode group for a non-aqueous secondary battery including a current collector, an active material layer carried on the current collector and a multi-layer porous membrane carried on the active material layer is used. The multi-layer porous membrane includes a first porous membrane and a second porous membrane. The first porous membrane contains metal oxide particles and a first binder. The second porous membrane contains resin particles and a second binder. The thickness of the multi-layer porous membrane is preferably 15 to 25 μm.