METHOD FOR PREPARING POROUS SEPARATION MEMBRANE COMPRISING ELASTIC MATERIAL, POROUS SEPARATION MEMBRANE PREPARED BY SAID METHOD, AND SECONDARY BATTERY COMPRISING SAID SEPARATION MEMBRANE

摘要

Disclosed is a method of manufacturing a porous separator, specifically, a method of manufacturing a porous separator including an elastic material, a separator manufactured by the method, and a secondary battery including the separator. According to one aspect, there is provided a porous separator in which an elastic material is uniformly dispersed in a polymer at a weight ratio of 40:60 to 5:95, and a value of elongation at break in a low tensile strength direction at room temperature is greater than or equal to 250%. According to another aspect, there is provided a method of manufacturing a porous separator including forming an extruded sheet by extruding, through an extruder, a mixture of a polymer and an elastic material at a weight ratio of 95:5 to 60:40, forming a film by annealing and stretching the extruded sheet, and forming a porous separator by heat setting the stretched film. Accordingly, a thermal shrinkage ratio of the film is reduced and an elongation at break is greatly increased, to provide a porous separator with improved stability.