# US 2019/0355950 A1 · Separator for electrochemical element, electrochemical element, automobile, and electronic device

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- Number: US 2019/0355950 A1
- Document ID: US20190355950A1
- Status: Published application
- Kind: A1
- Application number: 16/311,467
- Filed: 2016-06-27
- Published: 2019-11-21
- Earliest claimed: 2016-06-27
- Assignees: Nippon Kodoshi Corporation
- Applicants: Nippon Kodoshi Corporation
- Inventors: Norihiro WADA; Atsushi IGAWA; Masahiko UETA
- Web page: https://patentgrep.com/patent/US20190355950A1

## CPC

- H01M 50/44: Fibrous material
- H01G 9/02: Diaphragms; Separators
- H01G 11/52: Separators
- H01M 10/052: Li-accumulators
- H01M 50/417: Polyolefins
- H01M 50/429: Natural polymers
- H01M 50/4295: {Natural cotton, cellulose or wood}
- 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
- H01M 50/494: Tensile strength
- H01M 2220/20: Batteries in motive systems, e.g. vehicle, ship, plane
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01G: CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE (selection of specified materials as dielectric H01B3/00; capacitors having potential barriers H10D1/62, H10K10/10)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A separator for an electrochemical element interposed between a pair of electrodes, capable of holding an organic electrolytic solution contains an electrolyte. The separator is a wet-laid nonwoven fabric containing 10-50 mass % of thermoplastic synthetic fibers and 50-90 mass % of beaten regenerated cellulose fibers having a mean fiber length of 0.2-2.0 mm, the separator has a thickness of 10-70 μm and a density of 0.25-0.90 g/cm3, including two parts obtained by bisecting a cross-section of the separator in a thickness direction. Two A-parts with a small number of the thermoplastic synthetic fibers and B-part with a large number of the thermoplastic synthetic fibers, and the A and B parts are formed into a single layer in an integrated manner; a value obtained by dividing the number of thermoplastic synthetic fibers in the A part by the number of the thermoplastic synthetic fibers in the B part is 0.85 or less.

## Claims

### Claim 1

A separator for an electrochemical element, the separator being interposed between a pair of electrodes and configured to be capable of holding an organic electrolytic solution that contains an electrolyte,
wherein the separator is a wet-laid nonwoven fabric that contains 10 to 50 mass % of thermoplastic synthetic fibers and 50 to 90 mass % of beaten regenerated cellulose fibers having a mean fiber length of 0.2 to 2.0 mm, and the separator has a thickness of 10 to 70 μm and a density of 0.25 to 0.90 g/cm3, including two parts obtained by bisecting a cross-section of the separator in a thickness direction,
wherein the two parts are a part (A part) with a small number of the thermoplastic synthetic fibers and a part (B part) with a large number of the thermoplastic synthetic fibers, and the A part and the B part are formed into a single layer in an integrated manner,
wherein a value obtained by dividing the number of the thermoplastic synthetic fibers in the A part by the number of the thermoplastic synthetic fibers in the B part is 0.85 or less.

### Claim 2 (depends on 1)

The separator for an electrochemical element according to claim 1, wherein the thermoplastic synthetic fibers are one or more kinds of fibers selected from a polyester fiber, a polyolefin fiber, and an acrylic fiber.

### Claim 3 (depends on 1)

The separator for an electrochemical element according to claim 1, wherein a value obtained by dividing the number of the regenerated cellulose fibers in the B part by the number of the regenerated cellulose fibers in the A part is 0.85 or less.

### Claim 4 (depends on 1)

An electrochemical element including the separator for an electrochemical element according to claim 1.

### Claim 5 (depends on 4)

The electrochemical element according to claim 4, wherein the electrochemical element is any one of an aluminum electrolytic capacitor, an electric double layer capacitor, a lithium-ion capacitor, a lithium-ion secondary battery, and a lithium primary battery.

### Claim 6 (depends on 5)

The electrochemical element according to claim 5, wherein the part (B part) in the separator for an electrochemical element that has a large number of the thermoplastic synthetic fibers is disposed on a positive electrode of the electrochemical element.

### Claim 7 (depends on 4)

An electronic device equipped with the electrochemical element according to claim 4.

### Claim 8 (depends on 4)

An automobile equipped with the electrochemical element according to claim 4.