SEPARATOR, AND NONAQUEOUS ELECTROLYTE SECONDARY BATTERY INCLUDING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a separator which enables the further enhancement in safety of a nonaqueous electrolyte secondary battery.SOLUTION: A separator of the present invention comprises: a base material; and a heat-resistant layer provided on at least one face of the base material. The heat-resistant layer includes: a heat-resistant material higher than the base material in heatproof temperature; and a binding agent which melts at a first temperature. The base material has two or more porous layers differing from each other in pore size. The two or more porous layers include a first porous layer and a second porous layer. The first porous layer is the largest in pore size. The first porous layer is located in contact with the heat-resistant layer, and with the binding agent melting, it holds the melting binding agent. The second porous layer shuts down at a temperature higher than the first temperature.SELECTED DRAWING: Figure 3