MULTI-LAYERED POROUS FILM, SEPARATOR FOR POWER STORAGE DEVICE, AND POWER STORAGE DEVICE

• US 20180233730A1
• Filed: 08/09/2016
• Published: 08/16/2018
• Est. Priority Date: 08/12/2015
• Status: Abandoned Application

• Current Assignee: UBE Industries Limited
• Original Assignee: UBE Industries Limited
• Inventors: OHYA, Shusei, MATSUBAYASHI, Akihiro, KAMADA, Asumi
• Application Number:
  US15/750,769
• Publication Number:
  US 20180233730A1
• Time in Patent Office: Days
• CPC Class Codes: B32B 2250/03 3 layers
• CPC Class Codes: B32B 2250/242 All polymers belonging to those covered by group B32B27/32
• CPC Class Codes: B32B 2255/10 on synthetic resin layer or on natural or synthetic rubber layer
• CPC Class Codes: B32B 2255/102 synthetic resin or rubber layer being a foamed layer
• CPC Class Codes: B32B 2255/20 Inorganic coating
• CPC Class Codes: B32B 2255/26 Polymeric coating
• CPC Class Codes: B32B 2264/102 Oxide or hydroxide
• CPC Class Codes: B32B 2266/025 Polyolefin vinyl or acrylic copolymers B32B2266/0221, B32B2266/0242
• CPC Class Codes: B32B 2307/306 Resistant to heat
• CPC Class Codes: B32B 2307/724 Permeability to gases, adsorption
• CPC Class Codes: B32B 2307/732 Dimensional properties
• CPC Class Codes: B32B 2307/734 Dimensional stability
• CPC Class Codes: B32B 2457/10 Batteries
• CPC Class Codes: B32B 2457/16 Capacitors
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/205 the fillers creating voids or cavities, e.g. by stretching
• CPC Class Codes: B32B 27/32 comprising polyolefins comprising vinyl (co)polymers or acrylic (co)polymers B32B27/30
• CPC Class Codes: B32B 5/18 characterised by features of a layer of foamed material
• CPC Class Codes: B32B 5/32 at least two layers being foamed and next to each other
• CPC Class Codes: B32B 7/027 Thermal properties
• CPC Class Codes: H01G 11/06 : with one of the electrodes allowing ions to be reversibly doped thereinto, e.g. lithium ion capacitors [LIC]
• CPC Class Codes: H01G 11/52 : Separators
• CPC Class Codes: H01G 11/84 : Processes for the manufacture of hybrid or EDL capacitors, or components thereof
• CPC Class Codes: H01M 10/0525 : Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 50/406 : Moulding; Embossing; Cutting
• CPC Class Codes: H01M 50/417 : Polyolefins
• CPC Class Codes: H01M 50/446 : Composite material consisting of a mixture of organic and inorganic materials
• CPC Class Codes: H01M 50/457 : comprising three or more layers
• CPC Class Codes: H01M 50/489 : Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries

Abstract

A multi-layered porous film which minimizes the incidence of warpage, and having excellent liquid absorbing property performance in regard to absorbing electrolytic solution. The multi-layered porous film includes a porous layer containing a filler which is layered on at least one surface of a polyolefin porous film containing polypropylene as a raw material, the multi-layered porous film having a total lifting amount of 10 mm or less, which is the sum of the lifting amounts of the four sides, when a rectangular multi-layered porous film obtained by cutting a side length in the machine direction at 60 mm and another side length in the direction substantially orthogonal to machine direction at 60 mm was placed in an environment at 23° C. and a dew point of −20° C. or less for 1 hour; and the porous layer containing the filler is placed on the upper surface or the lower surface.

Claims

1. A multi-layered porous film comprising a porous layer containing a filler which is layered on at least one surface of a polyolefin porous film containing polypropylene as a raw material,

wherein the multi-layered porous film has a total lifting amount of 10 mm or less, which is the sum of the lifting amounts of the four sides, when a rectangular multi-layered porous film obtained by cutting a side length in the machine direction at 60 mm and another side length in the direction substantially orthogonal to machine direction at 60 mm is placed in an environment at 23°

C. and a dew point of −

20°

C. or less for 1 hour; and

the porous layer containing the filler is placed on the upper surface or the lower surface.

2. The multi-layered porous film according to claim 1, wherein the polyolefin porous film is a multi-layered structure including a polypropylene layer, and a polypropylene constituting the polypropylene layer has a weight average molecular weight of 500,000 to 1,000,000.

3. The multi-layered porous film according to claim 2, wherein the polyolefin porous film has a three-layer structure comprising the polypropylene layer as a surface layer and a polyethylene layer as an inner layer.

4. The multi-layered porous film according to claim 3, wherein a heat shrinkage percentage in the machine direction is 1% or less at 110°

C. and a heat shrinkage percentage in the direction substantially orthogonal to machine direction is −

1.7% to −

1.0% at 110°

C.

5. The multi-layered porous film according to claim 4, wherein the elongation percentage is 1.0% or more when tension is applied.

6. The multi-layered porous film according to claim 3, wherein the electrolytic solution absorption area is 1.5 cm² or more.

7. The multi-layered porous film according to claim 1, wherein the filler is an inorganic fine particle.

8. A separator for a power storage device comprising the multi-layered porous film according to claim 1.

9. A power storage device comprising:

the separator for a power storage device according to claim 8;

a positive electrode; and

a negative electrode.

10. A method for producing a multi-layered porous film comprising a polyolefin porous film prepared by stretching in a machine direction by a dry stretching method and having a porous layer containing a filler laminated on at least one side thereof,

wherein the multi-layered porous film has a total lifting amount of 10 mm or less, which is the sum of the lifting amounts of the four sides, when a rectangular multi-layered porous film obtained by cutting a side length in the machine direction at 60 mm and another side length in the direction substantially orthogonal to machine direction at 60 mm is placed in an environment at 23°

C. and a dew point of −

20°

C. or less for 1 hour; and

the porous layer containing the filler is placed on the upper surface or the lower surface.

11. The method of producing a multi-layered porous film according to claim 10, comprising heating the film while applying a tension of 0.04 N/mm or more per unit length of the film in the machine direction to the film, after applying a coating liquid containing the filler and a medium and drying at a predetermined drying temperature.

12. The method for producing a multi-layered porous film according to claim 10, wherein the filler is an inorganic fine particle.

13. The method of producing a multi-layered porous film according to claim 12, wherein the heating temperature is 40°

C. or more and 170°

C. or less.

14. The method for producing a multi-layered porous film according to claim 13, wherein the time for applying a tension after drying is 60 seconds or less.

15. The method for producing a multi-layered porous film according to claim 14, wherein the elongation percentage when tension is applied is 1.0% or more.

16. The multi-layered porous film produced by the method for producing a multi-layered porous film according to claim 10, wherein the multi-layered porous film has a total lifting amount of 10 mm or less, which is the sum of the lifting amounts of the four sides, when a rectangular multi-layered porous film obtained by cutting a side length in the machine direction at 60 mm and another side length in the direction substantially orthogonal to machine direction at 60 mm is placed in an environment at 23°

C. and a dew point of −

20°

C. or less for 1 hour; and

the porous layer containing the filler is placed on the upper surface or the lower surface.

18. The multi-layered porous film according to claim 16, wherein the polyolefin porous film is a multi-layered structure comprising a polypropylene layer.

19. The multi-layered porous film according to claim 18, wherein the polyolefin porous film has a three-layer structure comprising the polypropylene layer as a surface layer and a polyethylene layer as an inner layer.

20. The multi-layered porous film according to claim 16, wherein a polypropylene constituting the polypropylene layer has a weight average molecular weight of 500,000 to 1,000,000.

17. A multi-layered porous film comprising a porous layer containing a filler which is layered on at least one surface of a polyolefin porous film produced by a dry process, wherein the multi-layered porous film has a total lifting amount of 10 mm or less, which is the sum of the lifting amounts of the four sides, when a rectangular multi-layered porous film obtained by cutting a side length in the machine direction at 60 mm and another side length in the direction substantially orthogonal to machine direction at 60 mm is placed in an environment at 23°

C. and a dew point of −

20°

C. or less for 1 hour; and

the porous layer containing the filler is placed on the upper surface or the lower surface.