Method for manufacturing secondary battery separator and method for manufacturing lithium secondary battery

A method for manufacturing a secondary battery separator comprising a porous resin film in which pores have a three-dimensionally ordered structure and are in mutual communication via through-holes, the method comprising:

• uniformly dispersing spherical microparticles having a narrow particle size distribution in a dispersion medium to prepare a spherical microparticles-dispersed slurry;
• drying the spherical microparticles-dispersed slurry to obtain a spherical microparticles-dispersed film;
• heat treating the spherical microparticles-dispersed film to form a spherical microparticles-resin film in which the spherical microparticles are regularly arrayed in three-dimensions in a resin matrix;
• and
• forming the porous resin film having the pores, which are in mutual communication via through-holes and regularly arrayed in three-dimensions in the resin matrix, the forming comprising
• contacting the spherical microparticles-resin film with an organic acid, water, an alkaline solution or an inorganic acid other than hydrofluoric acid to dissolve and remove the spherical microparticles, to form the pores, or
• heating the spherical microparticles-resin film to remove the microparticles, to form the pores,
• wherein the dispersion medium comprises a resin precursor which constitutes the resin matrix,
• the surfaces of the spherical microparticles are inactive against the dispersion medium, and
• the spherical microparticles are selected from calcium carbonate, calcium oxide, titanium dioxide, cerium oxide, polymethyl methacrylate, polystyrene, and a complex of silica particles, titania particles or ceria particles and carboxymethyl cellulose or polymethyl methacrylate.