Composite microporous film, and production method and use thereof

Abstract

Disclosed is a composite microporous film which is obtained by applying a liquid mixture containing (a) a fluororesin which can be gelated, (b) a good solvent therefor and (c) a poor solvent therefor having a dipole moment of not more than 1.8 Debye to at least one surface of a polyolefin microporous film and drying it, thereby forming a coating layer composed of a porous body of the fluororesin on the surface. The composite microporous film has columnar through holes in the coating layer, and has an excellent balance among permeability, adhesion to electrodes, mechanical strength, thermal shrinkage resistance, shutdown characteristics and meltdown characteristics.

Description

technical field

[0001] The present invention relates to a composite microporous membrane, a method for producing the same, and an application thereof, and in particular, relates to permeability, adhesion to electrodes, mechanical strength, heat shrinkage resistance, sealing (Shauttodown) characteristics, and melting (Meltdown) characteristics. Composite microporous membrane with excellent balance, its production method and use. Background technique

[0002] Polyolefin microporous membranes are widely used in battery separators including lithium batteries, separators for various capacitors, various filters, moisture-permeable waterproof clothing, reverse osmosis membranes, ultrafiltration membranes, precision filtration membranes, etc. use.

[0003] In separators for lithium secondary batteries and lithium ion batteries, in order to prevent battery heat generation, fire, rupture accidents, etc. In addition to the function of stopping the reaction of the battery, it is also ...

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