Separator for power storage device and power storage device using the separator

• US 10,497,913 B2
• Filed: 01/14/2016
• Issued: 12/03/2019
• Est. Priority Date: 03/12/2015
• Status: Active Grant

• Current Assignee: Nippon Kodoshi Corporation
• Original Assignee: Nippon Kodoshi Corporation
• Inventors: Igawa, Atsushi, Wada, Norihiro, Ichimura, Takumi
• Primary Examiner(s): Douyette, Kenneth J
• Application Number:
  US15/552,862
• Publication Number:
  US 20180047961A1
• Time in Patent Office: 1,419 Days
• 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 11/58 Liquid electrolytes
• CPC Class Codes: H01G 9/02 Diaphragms; Separators
• 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 50/489 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
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors

Abstract

Provided is a separator for power storage device having excellent tearing strength, denseness, and resistance performance, and a power storage device provided with the separator for power storage device. The present invention constitutes a separator for power storage device including beatable regenerated cellulose fibers, wherein a CSF value X [ml] and a tear index Y [mN·m²/g] are within the ranges satisfying the following Formulae. The present invention also constitutes a power storage device in which the separator for power storage device is used, and which is formed by interposing the separator between one pair of electrodes.
0≤X≤150  Formula 1:
10≤Y≤70  Formula 2:
Y≥0.3X−5  Formula 3:

Claims

1. A separator for power storage device, comprising:

beatable regenerated cellulose fibers,

wherein a CS F value X [ml] and a tear index Y [mN·

m²/g] of the separator are within ranges satisfying Formulae 1 to 3;

0≤

X≤

150;

 

 

Formula 1;

10≤

Y≤

70; and

 

 

Formula 2;

Y≥

0.3X−

5, 

 

Formula 3;

wherein the separator is for power storage device which is interposed between a pair of electrodes and optionally holds an electrolyte-containing electrolytic solution, and

the power storage device is selected from the group consisting of an electric double-layer capacitor, a lithium-ion capacitor and a lithium-ion secondary battery.

2. The separator according to claim 1, wherein the CSF value X and the tear index Y are within range further satisfying Formula 4:

Y≤

0.1X+40. 

 

Formula 4;

3. The separator according to claim 2, wherein the CSF value X is within range further satisfying Formula 5:

0≤

X≤

50. 

 

Formula 5;

4. The separator according to claim 1, wherein a thickness of the separator is 10 to 80 μ

m.

5. The separator according to claim 1, wherein a density of the separator is 0.25 to 0.70 g/cm³.

6. A separator,

wherein the separator is for power storage,

the separator has a multilayered structure, and

at least one separator layer is the separator according to claim 1.

7. A power storage device, comprising:

a pair of electrodes; and

the separator of claim 1 interposed between the pair of electrodes.

8. The power storage device according to claim 7, wherein the power storage device is selected from the group consisting of an electric double-layer capacitor, a lithium-ion capacitor and a lithium-ion secondary battery.

9. The power storage device according to claim 7, wherein the power storage device is an electric double-layer capacitor.

10. The power storage device according to claim 7, wherein the power storage device is a lithium-ion capacitor.

11. The power storage device according to claim 7, wherein the beatable regenerated cellulose fibers consists of:

from 20 to 80% of a first fiber having a CSF value of from 350 to 0 ml and

from 80 to 20% of a second fiber having a CSF value of from 1 to 500 ml in which the value is once lowered to 0 ml (lower limit) and then turns upward by further beating.

12. The separator according to claim 1, wherein the beatable regenerated cellulose fibers consists of:

from 20 to 80% of a first fiber having a CSF value of from 350 to 0 ml and

from 80 to 20% of a second fiber having a CSF value of from 1 to 500 ml in which the value is once lowered to 0 ml (lower limit) and then turns upward by further beating.

13. The power storage device according to claim 7, wherein the beatable regenerated cellulose fiber comprises at least two regenerated cellulose fibers having different degrees of beat.

14. The separator according to claim 1, wherein the beatable regenerated cellulose fiber comprises at least two regenerated cellulose fibers having different degrees of beat.