PET nonwoven fabric as a separator for secondary batteries and separator for secondary batteries comprising these

This invention relates to a PET nonwoven fabric for a separator for a secondary battery and a separator for a secondary battery, which includes this. The PET nonwoven fabric includes first fibers, which are composed of PET, having a melting temperature of 240 ° C or more, and second fibers which are composed of PET, having a melting temperature of 180 to 220 ° C, or fibers, the two types of fibers with different diameters, and has a fine pore size and uniform pore size distribution as well as excellent surface properties, few surface defects, high mechanical strength and is very well suited for mass production. Even when the temperature of a battery at 200 ° C or more is increased, the PET nonwoven fabric a heat resistance, which prevents thermal runaway and does not lead to melting and shrinkage.