1 . A method of manufacturing a separator, including: (a) laminating a first porous support and a second porous support to obtain a laminate; (b) forming a functional layer by applying a composition including a binder and a solvent on both sides of the laminate and drying the composition; and (c) dividing the laminate into two separators along an interface formed by the lamination, wherein the thickness of each of the first porous support and the second porous support is 10 m or less, and wherein the first porous support and the second porous support are pressed to face each other during the lamination, and both ends of the first porous support and the second porous support in the transverse direction (TD) are attached to each other by a physical means selectively applied to both ends in the transverse direction (TD) of the first porous support and the second porous support.
2 . The method of claim 1 , wherein the each of the first porous support and the second porous support includes one selected from the group consisting of polyethylene, polypropylene, polybutylene, polymethylpentene, ethylene vinyl acetate, ethylene butyl acrylate, ethylene ethyl acrylate, and combinations or copolymers of two or more thereof.
3 . The method of claim 1 , wherein the binder is one selected from the group consisting of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trichloroethylene, polymethyl methacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinyl acetate, ethylene vinyl acetate, polyimide, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, hydroxyethyl cellulose, cyanoethyl sucrose, pullulan, carboxymethyl cellulose, polyvinyl alcohol, polyvinyl butyral, an acrylonitrile-acrylic acid copolymer, an ethylene-acrylic acid copolymer, a styrene-butadiene copolymer, an alkyl acrylate-acrylonitrile copolymer, polyethylene glycol, acrylic rubber, and a combination of two or more thereof.