Separator and secondary battery including the separator

Abstract

Provided is a separator including a first layer which consists of a porous polyolefin and a secondary battery utilizing the separator. A first layer exhibits a minimum height equal to or more than 50 cm and equal to or less than 150 cm when a ball having a diameter of 14.3 mm and a weight of 11.9 g located over the first layer is allowed to free fall causing a split in the first layer. A tearing strength of the first layer in a width direction, measured with an Elmendorf tearing method, is equal to or more than 1.5 mN/μm. A tensile elongation of the first layer is equal to or longer than 0.5 mm until a load decreases to 25% of a maximum load in a load-elongation curve in machine direction measured by a rectangular tearing method.

Dependencies are inferred from the claim text.