# US 12,603,292 B2 · Energy storage device

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- Number: US 12,603,292 B2
- Document ID: US12603292B2
- Status: Granted
- Kind: B2
- Application number: 18/022,661
- Filed: 2021-08-23
- Published: 2023-10-05
- Granted: 2026-04-14
- Earliest claimed: 2020-08-24
- Assignees: GS Yuasa International Ltd.
- Applicants: GS Yuasa International Ltd.
- Inventors: Norio Yamatani; Morito Tanabe; Takeshi Sasaki
- Web page: https://patentgrep.com/patent/US12603292B2

## CPC

- H01M 4/625: {Carbon or graphite}
- H01G 11/06: with one of the electrodes allowing ions to be reversibly doped thereinto, e.g. lithium ion capacitors [LIC]
- H01G 11/26: characterised by their structure, e.g. multi-layered, porosity or surface features
- H01G 11/78: Cases; Housings; Encapsulations; Mountings
- H01M 4/13: Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M 4/587: for inserting or intercalating light metals
- H01M 4/62: Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M 10/04: Construction or manufacture in general (H01M10/058, H01M10/12, H01M10/28, H01M10/38 take precedence)
- H01M 10/052: Li-accumulators
- H01M 10/0587: of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
- H01M 50/538: Connection of several leads or tabs of wound or folded electrode stacks
- H01M 2004/021: {Physical characteristics, e.g. porosity, surface area}
- H01M 2004/027: {Negative electrodes}
- Y02E 60/10: Energy storage using batteries
- Y02P 70/50: Manufacturing or production processes characterised by the final manufactured product
- 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
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

One aspect of the present invention is an energy storage device satisfying the following formula 1, in which a flat electrode assembly obtained by winding a positive electrode and a negative electrode with a separator interposed therebetween and having two curved surface portions facing each other, and a case that houses the electrode assembly, and at least one of the positive electrode and the negative electrode includes an active material layer containing active material particles and a fibrous conductive agent. In the formula 1, X is a distance from a distal end of one of the curved surface portions to the inner surface of the case facing the distal end of the curved surface portion as viewed in the winding axis direction of the electrode assembly. R is a length of a periphery of the one curved surface portion as viewed in the winding axis direction of the electrode assembly. D is an average particle size D50 of the active material particles. A is a surface roughness Ra of the active material layer. (R/D)A≥2X 1

## Claims

### Claim 1

An energy storage device satisfying a following formula 1, comprising:
a flat electrode assembly obtained by winding a positive electrode and a negative electrode with a separator interposed therebetween and having two curved surface portions facing each other; and
a case that houses the electrode assembly,
wherein at least one of the positive electrode and the negative electrode includes an active material layer containing active material particles and a fibrous conductive agent:
(R/D)A≥2X (formula 1)
wherein X is a distance from a distal end of one of the curved surface portions to the inner surface of the case facing the distal end of the curved surface portion as viewed in the winding axis direction of the electrode assembly, R is a length of a periphery of the one curved surface portion as viewed in the winding axis direction of the electrode assembly, D is an average particle size D50 of the active material particles, and A is a surface roughness Ra of the active material layer.

### Claim 2

An energy storage device satisfying a following formula 2, comprising:
a flat electrode assembly obtained by winding a positive electrode and a negative electrode with a separator interposed therebetween and having two curved surface portions facing each other; and
a case that houses the electrode assembly,
wherein at least one of the positive electrode and the negative electrode includes an active material layer containing active material particles and a fibrous conductive agent:
A/D≥0.2 (formula 2)
wherein D is an average particle size D50 of the active material particles, and A is a surface roughness Ra of the active material layer, and
the energy storage device further satisfies the following formula 1:
(R/D)A≥2X (formula 1)
wherein X is a distance from a distal end of one of the curved surface portions to the inner surface of the case facing the distal end of the curved surface portion as viewed in the winding axis direction of the electrode assembly, R is a length of a periphery of the one curved surface portion as viewed in the winding axis direction of the electrode assembly, and D and A have the same meaning as D and A in the formula 2.

### Claim 3 (depends on 1)

The energy storage device according to claim 1, further satisfying the following formula 3:
0.06≤X/R≤0.12 (formula 3)
wherein X and R have the same meaning as X and R in the formula 1.

### Claim 4 (depends on 1)

The energy storage device according to claim 1, wherein a content of the fibrous conductive agent in the active material layer is 0.01% by mass or more.

### Claim 5 (depends on 1)

The energy storage device according to claim 1, wherein an average length of the fibrous conductive agent is larger than an average particle size D50 of the active material particles.

### Claim 6 (depends on 1)

The energy storage device according to claim 1, wherein the active material particles are present in a state of secondary particles in which a ratio of an average particle size D50 to a primary particle size is 3 or less, or primary particles that are not substantially aggregated.

### Claim 7 (depends on 1)

The energy storage device according to claim 1, wherein the positive electrode has the active material layer containing the active material particles and the fibrous conductive agent.