# US 12,119,439 B2 · Energy storage device

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- Number: US 12,119,439 B2
- Document ID: US12119439B2
- Status: Granted
- Kind: B2
- Application number: 16/764,212
- Filed: 2018-11-22
- Published: 2020-12-17
- Granted: 2024-10-15
- Earliest claimed: 2017-11-30
- Assignees: GS Yuasa International Ltd.
- Applicants: GS Yuasa International Ltd.
- Inventors: Yudai Kawasoe; Kenta Nagamine
- Web page: https://patentgrep.com/patent/US12119439B2

## CPC

- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 10/0569: characterised by the solvents
- H01M 10/0468: {Compression means for stacks of electrodes and separators}
- H01M 10/0481: {Compression means other than compression means for stacks of electrodes and separators}
- H01M 10/052: Li-accumulators
- H01M 10/0563: Liquid materials, e.g. for Li-SOCl2 cells
- H01M 10/0567: characterised by the additives
- H01M 10/054: Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
- H01M 50/103: prismatic or rectangular (H01M50/109, H01M50/11 take precedence)
- H01M 2220/20: Batteries in motive systems, e.g. vehicle, ship, plane
- H01M 2300/002: Inorganic electrolyte
- H01M 2300/0034: Fluorinated solvents
- H01M 2300/004: Three solvents
- H01M 2300/0042: Four or more solvents
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

One aspect of the present invention is an energy storage device including: an electrode assembly including a negative electrode and a positive electrode that are stacked on each other with a separator interposed therebetween; a nonaqueous electrolyte containing a nonaqueous solvent; and a flat outer case housing the electrode assembly and the nonaqueous electrolyte, wherein the electrode assembly is disposed in the outer case in a compressed state so that the electrode assembly is pressurized in a direction of stack, a surface pressure acting on the outer case in the direction of stack is 1 k Pa or more, the nonaqueous solvent contains a fluorinated cyclic carbonate, and the nonaqueous electrolyte has an electric conductivity at 25° C. of 0.75 S/m or more.

## Claims

### Claim 1

An energy storage device comprising: an electrode assembly including a negative electrode and a positive electrode that are stacked on each other with a separator interposed therebetween; a nonaqueous electrolyte containing a nonaqueous solvent; and a flat outer case housing the electrode assembly and the nonaqueous electrolyte, wherein the electrode assembly is disposed in the outer case in a compressed state so that the electrode assembly is pressurized in a direction of stack,
the energy storage device further comprises a pressing member that pressurizes the electrode assembly in the direction of stack,
a surface pressure acting on the outer case in the direction of stack is 100 kPa or more, the nonaqueous solvent contains a fluorinated cyclic carbonate, the nonaqueous electrolyte has an electric conductivity at 250 C of 0.75 S/m or more and 0.95 S/m or less, and the nonaqueous solvent further contains a linear carbonate.

### Claim 2 (depends on 1)

The energy storage device according to claim 1, wherein a volume percentage of the fluorinated cyclic carbonate in the nonaqueous solvent is 3 vol % or more and 50 vol % or less.

### Claim 3 (depends on 1)

The energy storage device according to claim 1, wherein the fluorinated cyclic carbonate is fluoroethylene carbonate.

### Claim 4 (depends on 1)

The energy storage device according to claim 1, wherein a maximum expansion rate of the negative electrode excluding a negative electrode substrate after charging is 10% or more and 15% or less relative to a thickness of the negative electrode after discharging.

### Claim 5 (depends on 1)

The energy storage device according to claim 1, wherein the negative electrode has a porosity of 25% or more and 40% or less after discharging.

### Claim 6 (depends on 1)

The energy storage device according to claim 1, wherein the linear carbonate includes dimethyl carbonate and ethyl methyl carbonate.

### Claim 7 (depends on 1)

The energy storage device according to claim 1, wherein a volume percentage of ethylene carbonate in the nonaqueous solvent is 1 vol % or less.

### Claim 8 (depends on 1)

The energy storage device according to claim 1, wherein a volume percentage of the fluorinated cyclic carbonate in the nonaqueous solvent is 10 vol % or more and 30 vol % or less, and a volume percentage of the linear carbonate in the nonaqueous solvent is 70 vol % or more and 90 vol % or less.