# US 12,191,506 B2 · Redox flow battery cell, cell stack and redox flow battery system

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- Number: US 12,191,506 B2
- Document ID: US12191506B2
- Status: Granted
- Kind: B2
- Application number: 17/626,382
- Filed: 2019-07-18
- Published: 2022-08-18
- Granted: 2025-01-07
- Earliest claimed: 2019-07-18
- Assignees: Sumitomo Electric Industries, Ltd.
- Applicants: Sumitomo Electric Industries, Ltd.
- Inventors: Yuta Ochi
- Web page: https://patentgrep.com/patent/US12191506B2

## CPC

- H01M 4/96: Carbon-based electrodes
- H01M 8/04186: of liquid-charged or electrolyte-charged reactants
- H01M 8/1009: with one of the reactants being liquid, solid or liquid-charged (H01M8/12 takes precedence)
- H01M 8/188: {by recharging of redox couples containing fluids; Redox flow type batteries}
- H01M 2004/8684: {Negative electrodes}
- H01M 2004/8689: {Positive electrodes}
- Y02E 60/50: Fuel cells
- 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

A redox flow battery cell includes a positive electrode and a negative electrode, and each of the positive electrode and the negative electrode is an assembly containing a plurality of carbon fibers, and a quantity per unit area of the positive electrode is larger than a quantity per unit area of the negative electrode.

## Claims

### Claim 1

A redox flow battery cell comprising a positive electrode and a negative electrode, wherein
each of the positive electrode and the negative electrode is an assembly consisting essentially of a carbon fiber assembly consisting of a plurality of carbon fibers, and
a mass of the carbon fiber assembly per unit area of the positive electrode is larger than a mass of the carbon fiber assembly per unit area of the negative electrode.

### Claim 2 (depends on 1)

The redox flow battery cell according to claim 1, wherein a ratio of the mass of the assembly per unit area of the positive electrode to the mass of the assembly per unit area of the negative electrode is no less than 107%.

### Claim 3 (depends on 1)

The redox flow battery cell according to claim 1, wherein the mass of the assembly per unit area of the positive electrode and the mass of the assembly per unit area of the negative electrode are no less than 20 g/m2 and no more than 500 g/m2.

### Claim 4 (depends on 1)

The redox flow battery cell according to claim 1, wherein an average fiber diameter of the carbon fibers is no more than 20 μm.

### Claim 5 (depends on 1)

The redox flow battery cell according to claim 1, wherein the carbon fiber assembly is in a form of felt, cloth or paper.

### Claim 6 (depends on 5)

The redox flow battery cell according to claim 5, wherein an average fiber diameter of the carbon fibers is no less than 1 μm and no more than 20 μm.

### Claim 7 (depends on 1)

A cell stack comprising a plurality of the redox flow battery cells according to claim 1.

### Claim 8 (depends on 7)

A redox flow battery system comprising the cell stack according to claim 7.

### Claim 9 (depends on 1)

A redox flow battery system comprising the redox flow battery cell according to claim 1.