Separator for electric double layer capacitors, and electric double layer capacitor

Patent metadata

Field	Value
Publication number	US-10020124-B2
Application number	US-201514750063-A
Country	US
Kind code	B2
Filing date	Jun 25, 2015
Priority date	Dec 26, 2012
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

A separator for electric double layer capacitor comprising a fiber sheet containing 10% by mass (relative to 100% by mass of fiber sheet) of polyvinyl alcohol fibers (fibers A) having a hot water-dissolving temperature of lower than 100° C. and higher than 85° C., the separator having a density within a range of 0.25 to 0.7 g/cm 3 , and a thickness within a range of not less than 5 μm and less than 40 μm.

First claim

What is claimed is:

1. A separator for an electric double layer capacitor, comprising:
a fiber sheet containing polyvinyl alcohol fibers A and polyvinyl alcohol fibers B;
wherein:
the fibers A have a hot water-dissolving temperature of lower than 100° C. and higher than 85° C.;
the fibers B have a hot water-dissolving temperature of lower than 80° C.;
the fiber sheet contains at least 10% by mass of the fibers A relative to 100% by mass of the fiber sheet;
the separator has a density within a range of 0.25 to 0.7 g/cm 3 ;
the separator has a thickness within a range of not less than 5 μm and less than 40 μm;
the fibers A have a single fiber fineness smaller than a single fiber fineness of the fibers B; and
a ratio of the single fiber fineness of the fibers A to the single fiber fineness of the fibers B is from 5/95 to 35/65.

2. The separator for an electric double layer capacitor according to claim 1 , wherein a mass ratio between the fibers A and the fibers B satisfies A/B=40/60 to 99/1.

3. The separator for an electric double layer capacitor according to claim 1 , wherein the fiber sheet further contains cellulose fibers.

4. The separator for an electric double layer capacitor according to claim 3 , wherein the cellulose fibers are beaten fibers of organic solvent spun cellulose fibers or natural cellulose fibers.

5. The separator for an electric double layer capacitor according to claim 1 , wherein:
a thickness of the separator is within a range of 5 to 30 μm; and
a strength of the separator in a longitudinal direction (kg/15 mm)/thickness of the separator (μm) is larger than 0.025.

6. An electric double layer capacitor comprising the separator for an electric double layer capacitor according to claim 1 .

7. The separator for electric double layer capacitor according to claim 1 , wherein:
the fiber sheet contains 30% by mass or more of fibers A relative to 100% by mass of the fiber sheet; and
a mass ratio between the fibers A and the fibers B satisfies A/B=40/60 to 85/15.

8. The separator for electric double layer capacitor according to claim 1 , wherein the fiber sheet contains 50% by mass or more of fibers A relative to 100% by mass of the fiber sheet.

9. The separator for electric double layer capacitor according to claim 1 , wherein the fibers A have a single fiber fineness of from 0.01 dtex to 0.8 dtex and a fiber length of from 1 m to 5 mm.

10. The separator for electric double layer capacitor according to claim 1 , wherein the fibers A have a single fiber fineness of from 0.1 dtex to 0.8 dtex and a fiber length of from 0.5 mm to 10 mm.

11. The separator for electric double layer capacitor according to claim 1 , wherein the fibers A are obtained by spinning only from a vinyl alcohol polymer.

12. The separator for electric double layer capacitor according to claim 1 , wherein the fibers A are blend spun fibers or conjugated spun islands-in-the-sea fibers.

13. The separator for electric double layer capacitor according to claim 1 , wherein the fibers A are obtained by spinning a vinyl alcohol polymer having an average degree of polymerization of 1,000 to 5,000 and a degree of saponification of not lower than 95% by mole, where the average degree of polymerization is a viscosity average degree of polymerization determined based on a viscosity of an aqueous solution at 30° C.

14. The separator for electric double layer capacitor according to claim 1 , wherein the fibers B have a single fiber fineness of from 0.01 dtex to 3 dtex and a fiber length of from 1 mm to 5 mm.

15. The separator for electric double layer capacitor according to claim 1 , wherein the fibers B are obtained by spinning only from a vinyl alcohol polymer.

16. The separator for electric double layer capacitor according to claim 1 , wherein the fibers B are blend spun fibers or conjugated spun islands-in-the-sea fibers.

17. The separator for electric double layer capacitor according to claim 1 , wherein the fibers B are obtained by spinning a vinyl alcohol polymer having an average degree of polymerization of 300 to 500 and a degree of saponification of 80 to 99% by mole, where the average degree of polymerization is a viscosity average degree of polymerization determined based on a viscosity of an aqueous solution at 30° C.

18. A separator for an electric double layer capacitor, comprising:
a fiber sheet comprising polyvinyl alcohol fibers A, polyvinyl alcohol fibers B, and cellulose fibers;
wherein:
the fibers A have a hot water-dissolving temperature of lower than 100° C. and higher than 85° C.;
the fibers A have a single fiber fineness of from 0.01 dtex to 0.8 dtex and a fiber length of from 1 mm to 5 mm;
the fibers B have a hot water-dissolving temperature of lower than 80° C.;
the fibers B have a single fiber fineness of from 0.01 dtex to 3 dtex and a fiber length of from 1 mm to 5 mm;
the fiber sheet contains at least 10% by mass of the fibers A relative to 100% by mass of the fiber sheet;
the fibers A have a single fiber fineness smaller than a single fiber fineness of the fibers B; and
a ratio of the single fiber fineness of the fibers A to the single fiber fineness of the fibers B is from 5/95 to 35/65;
the separator has a density within a range of 0.25 to 0.7 g/cm 3 ;
the separator has a thickness within a range of 5 to 30 μm; and
a strength of the separator in a longitudinal direction (kg/15 mm)/thickness of the separator (μm) is larger than 0.025.

Assignees

• Kuraray Co

Inventors

• Hayakawa Tomohiro
• Kawai Hiroyuki
• Hayashi Hideo

Classifications

• H01M50/489

  Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties · CPC title

• H01M50/429

  Natural polymers · CPC title

• H01M50/414

  Synthetic resins, e.g. thermoplastics or thermosetting resins · CPC title

• Y02E60/13

  Energy storage using capacitors · CPC title

• H01M2/162

  Electricity · mapped topic