Separator having porous coating layer, method for manufacturing the same and electrochemical device having the same

Abstract

A separator includes a porous substrate having a plurality of pores; and a porous coating layer formed on at least one surface of the porous substrate and made of a mixture of a binder and a plurality of inorganic particles, wherein the binder includes a crosslinked binder. This separator may improve high temperature cycle performance, discharge characteristics and thermal resistance of an electrochemical device since the separator exhibits improved insolubility and impregnation to electrolyte and improved thermal resistance.

1 . A separator, comprising:
 a porous substrate having a plurality of pores; and   a porous coating layer formed on at least one surface of the porous substrate and made of a mixture of a binder and a plurality of inorganic particles,   wherein the binder includes a crosslinked binder.   
     
     
         2 . The separator according to  claim 1 ,
 wherein the crosslinked binder is crosslinked by means of reaction among binders selected from the group consisting of polymer having at least three reactive groups, low molecule having at least three reactive groups, or their mixtures.   
     
     
         3 . The separator according to  claim 1 ,
 wherein the crosslinked binder is obtained by crosslinking a binder selected from the group consisting of polymer having at least two reactive groups, low molecule having at least two reactive groups, or their mixtures, by using a crosslinking agent.   
     
     
         4 . The separator according to  claim 1 ,
 wherein the binder is a mixture of a crosslinked binder and a non-crosslinked binder.   
     
     
         5 . The separator according to  claim 4 ,
 wherein the non-crosslinked binder is any one selected from the group consisting of polyvinylidene fluoride-co-hexafluoropropylene, polyvinylidene fluoride-co-trichloroethylene, polymethylmethacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylacetate, polyethylene-co-vinyl acetate, polyethylene oxide, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethylpullulan, cyanoethylpolyvinylalcohol, cyanoethylcellulose, cyanoethylsucrose, pullulan, carboxyl methyl cellulose, acrylonitrile-styrene-butadiene copolymer and polyimide, or their mixtures.   
     
     
         6 . The separator according to  claim 1 ,
 wherein the inorganic particles have a size of 0.01 to 10 μm.   
     
     
         7 . The separator according to  claim 1 ,
 wherein a weight ratio of the inorganic particles and the crosslinked binder is 50:50 to 99:1.   
     
     
         8 . The separator according to  claim 1 ,
 wherein the porous coating layer has a pore size of 0.01 to 10 μm and a porosity of 5 to 95%.   
     
     
         9 . The separator according to  claim 1 ,
 wherein the porous substrate is a polyolefin porous film.   
     
     
         10 . The separator according to  claim 1 ,
 wherein the porous substrate is a non-woven fabric made of any one polymer selected from the group consisting of polyethyleneterephthalate, polybutyleneterephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenyleneoxide, polyphenylenesulfidro and polyethylenenaphthalene, or their mixtures.   
     
     
         11 . A method for manufacturing a separator, comprising:
 (S1) preparing a coating solution containing a crosslinkable binder component selected from the group consisting of a crosslinkable polymer, a crosslinkable low molecule, and their mixtures;   (S2) adding inorganic particles to the coating solution such that the inorganic particles are dispersed in the coating solution;   (S3) applying the coating solution in which the inorganic particles are dispersed to at least one surface of a porous substrate to form a coating layer; and   (S4) crosslinking the crosslinkable binder component in the coating layer to form a porous coating layer.   
     
     
         12 . The method for manufacturing a separator according to  claim 11 ,
 wherein the crosslinkable binder component is any one selected from the group consisting of polymer having at least three reactive groups, low molecule having at least three reactive groups, or their mixtures.   
     
     
         13 . The method for manufacturing a separator according to  claim 11 ,
 wherein the coating solution contains a crosslinking agent and a crosslinkable binder component selected from the group consisting of polymer having at least two reactive groups, low molecule having at least two reactive groups, or their mixtures.   
     
     
         14 . An electrochemical device, which includes a cathode, an anode and a separator interposed between the cathode and the anode,
 wherein the separator is a separator defined in  claim 1 .