Nonaqueous electrolyte secondary battery having separators with base material and heat-resistant layer on coiling outer peripheral side

Abstract

Provided is a nonaqueous electrolyte secondary batterywhich, in cases where separatorseach having a heat-resistant layeron only one face thereof are used, has an excellent thermal stability and thus a higher safety and reliability when the batteryreaches a high temperature. Such a nonaqueous electrolyte secondary batteryincludes a positive electrodein which a positive electrode active material layeris provided on both faces of a positive electrode current collector, a negative electrodein which a negative electrode active material layeris provided on both faces of a negative electrode current collector, at least two separatorseach having a heat-resistant layeron one face of a base material, and an electrolyte. The nonaqueous electrolyte secondary battery has an electrode assemblyin which the positive electrodeand the negative electrodeare stacked on top of one another with the separatorsinterposed therebetween. The at least two separatorsare disposed in such a way that, for each separator, the heat-resistant layeris positioned on the same side with respect to the base materialin the stacking direction.