Laminated porous film, non-aqueous electrolyte secondary battery separator, and non-aqueous electrolyte secondary battery

Patent metadata

Field	Value
Publication number	US-2016268570-A1
Application number	US-201415031365-A
Country	US
Kind code	A1
Filing date	Oct 27, 2014
Priority date	Oct 28, 2013
Publication date	Sep 15, 2016
Grant date	—

Abstract

As a laminated porous film realizing excellent handling properties in a low-humidity environment, a laminated porous film in which a layer containing a polymer is laminated on at least one side of a polyolefin porous film, satisfying the following (1) and (2) is provided. (1) When the laminated porous film has left still for 1 hour in an environment at a temperature of 23° C. and a humidity of 50%, a lifting amount of the side parallel with the direction perpendicular to the machine direction is 8 mm or more. (2) When the laminated porous film has left still for 1 hour in an environment at a temperature of 23° C. and a humidity of 5%, a lifting amount of the side parallel with the machine direction is 15 mm or less.

First claim

1 . A laminated porous film in which a layer comprising a polymer is laminated on at least one side of a polyolefin porous film, the laminated porous film satisfying the following (1) and (2):
(1) when the laminated porous film has been left still for 1 hour in an environment at a temperature of 23° C. and a humidity of 50%, a lifting amount of the side parallel with the direction perpendicular to the machine direction is 8 mm or more. (2) when the laminated porous film has been left still for 1 hour in an environment at a temperature of 23° C. and a humidity of 5%, the lifting amount of the side parallel with the machine direction is 15 mm or less.

2 . The laminated porous film according to claim 1 , wherein the modulus of elasticity of the polyolefin porous film in the direction perpendicular to the machine direction is lower than the modulus of elasticity in the machine direction.

3 . The laminated porous film according to claim 1 , wherein the polymer is a hygroscopic polymer.

4 . The laminated porous film according to claim 1 , wherein the layer comprising a polymer further comprising fine particles.

5 . The laminated porous film according to claim 1 , wherein the layer comprising a polymer is laminated on one side of the polyolefin porous film.

6 . The laminated porous film according to claim 1 , wherein the polymer is a water-soluble polymer.

7 . The laminated porous film according to claim 1 , wherein the difference between the moisture content when the laminated porous film has been left still for 1 hour in an environment at a temperature of 23° C. and a humidity of 50% and the moisture content when the laminated porous film has been left still for 1 hour in an environment at a temperature of 23° C. and a humidity of 5% is 45 mg/m 2 or more.

8 . A laminated porous film obtained by:
applying a coating liquid containing a polymer to at least one face of a polyolefin porous film; drying the polyolefin porous film to which the coating liquid is applied; and applying a film tension to the dried polyolefin porous film for 10 seconds or more in a predetermined temperature environment, the film tension giving an elongation percentage of 0.3% to 2% when it is applied to a polyolefin porous film before application of a coating liquid in the same temperature environment as the predetermined temperature environment, wherein a lifting amount of a side parallel with a direction orthogonal to a machine direction when the laminated porous film is left still for 1 hour in an environment at a temperature of 23° C. and a humidity of 50% is 8 mm or more, and a lifting amount of a side parallel with the machine direction when the laminated porous film is left still for 1 hour in an environment at a temperature of 23° C. and a humidity of 5% is 15 mm or less.

9 . A method for producing a laminated porous film comprising the steps (a), (b) and (c):
(a) applying a coating liquid containing a polymer to at least one face of a polyolefin porous film; (b) drying the polyolefin porous film to which the coating liquid is applied; and (c) applying a film tension to the dried polyolefin porous film for 10 seconds or more in a predetermined temperature environment, the film tension giving an elongation percentage of 0.3% to 2% when it is applied to a polyolefin porous film before application of a coating liquid in the same temperature environment as the predetermined temperature environment.

10 . A non-aqueous electrolyte secondary battery separator comprising the laminated porous film according to claim 1 .

11 . A non-aqueous electrolyte secondary battery comprising the non-aqueous electrolyte secondary battery separator according to claim 10 .

Assignees

• Sumitomo Chemical Co

Inventors

• Wang Jian
• Hasegawa Hirohiko

Classifications

• C08J2323/02

  not modified by chemical after treatment · CPC title

• H01M2220/30

  Batteries in portable systems, e.g. mobile phone, laptop · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M50/417

  Polyolefins · CPC title

• H01M50/426

  Fluorocarbon polymers · CPC title