| 摘要 |
The present invention relates to a method for manufacturing a separator, a separator manufactured by the method, and an electrochemical device comprising the separator and, particularly, to a method for manufacturing a separator, a separator manufactured by the method, and an electrochemical device comprising the separator, wherein the concentration of a pore forming agent in a solvent is maintained within a predetermined range in the process of extracting the pore forming agent. According to an embodiment of the present invention, a method for manufacturing a separator is provided, comprising the steps of: mixing polymer particles with a pore forming agent to prepare a mixture; extruding the mixture by an extruder to form an extruded sheet; stretching the extruded sheet to form a membrane; removing the pore forming agent from the formed membrane using a solvent in one or more extracting baths, wherein 0.3 wt% or less of the concentration of the pore forming agent in the solvent is maintained; and fixing the pore forming agent-removed membrane by heat to form a porous separator. According to the present invention, a separator having superior air porosity and air permeability can be manufactured without the problems of poor heat resistance, closed pores, and reduced thickness. [Reference numerals] (S1) Step of preparing a mixture; (S2) Step of forming an extruded sheet; (S3) Step of forming a membrane; (S4) Step of maintaining concentration of a pore forming agent; (S5) Step of forming a porous separator |
