Apparatus for manufacturing a fine porous film for a separation film of a battery and method for manufacturing a film using same

Abstract

The present invention relates to an apparatus and method for manufacturing a fine porous film to be used as a separation film of a secondary battery. The apparatus for manufacturing the fine porous film of the present invention comprises: a T-shaped die (20) for forming a precursor film by extruding a melted resin generated by melting a partially crystalline resin through the front end of a nozzle; a guide roller (50) arranged at a downstream side of the extrusion direction of the T-shaped die (20) so as to move and guide the precursor film (F1) at a predetermined draft ratio; a precursor film cooling means (40) for providing, in the moving direction of the precursor film, a flow of cooling air over either or both of the front and back surfaces of the precursor film so as to cool the precursor film; and a film elongation means for applying a tensile force, in an axial direction or in biaxial directions, to the cooled film while same is passing through the precursor film cooling means (40).

Description

Technical field [0001] The present invention relates to an apparatus and method for manufacturing a microporous film (microporous film). In particular, the present invention relates to a method for manufacturing a microporous film, which presses a part of the crystalline resin through a T-shaped extrusion die to form a precursor film, and the precursor film is annealed and stretched to be suitable for battery Microporous separation membrane. Background technique [0002] Recently, as electronic devices such as portable communication devices, portable notebook computers, etc. have become popular and rapidly increased in use, rechargeable batteries as electronic device batteries are required to have characteristics of lighter weight, high current density, and low self-discharge. [0003] Along with this trend, separators for rechargeable batteries are widely used as microporous membranes formed with multiple micropores to ensure good ion permeability between electrodes. Microporous...

AI Technical Summary

Problems solved by technology

[0007] However, according to the above-mentioned conventional precursor film manufacturing method, since the moving precursor film is cooled by contacting the rotating cooling roll, it is not only difficult to perform uniform cooling, but also difficult to adjust the cooling rate.

This makes it difficult to adjust the pore size or porosity of the microporous membrane, which in turn leads to technical limitations in improving the porosity and porosity of the membrane.

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