# US 8,771,857 B2 · Redox flow battery

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- Number: US 8,771,857 B2
- Document ID: US8771857B2
- Status: Granted
- Kind: B2
- Application number: 13/505,281
- Filed: 2011-04-27
- Published: 2012-09-27
- Granted: 2014-07-08
- Earliest claimed: 2010-04-27
- Assignees: Sumitomo Electric Industries, Ltd.
- Applicants: Toshio Shigematsu; Yongrong Dong; Takahiro Kumamoto
- Inventors: Toshio Shigematsu; Yongrong Dong; Takahiro Kumamoto
- Web page: https://patentgrep.com/patent/US8771857B2

## CPC

- H01M 50/77: with external circulating path
- H01M 8/188: {by recharging of redox couples containing fluids; Redox flow type batteries}
- H01M 2300/0088: Composites
- H01M 2300/0091: in the form of mixtures
- Y02E 60/10: Energy storage using batteries
- 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 (RF) battery performs charge and discharge by supplying a positive electrode electrolyte and a negative electrode electrolyte to a battery cell. Each of the positive electrode electrolyte and the negative electrode electrolyte contains a vanadium (V) ion as active material. At least one of the positive electrode electrolyte and the negative electrode electrolyte further contains another metal ion, for example, a metal ion such as a manganese ion that exhibits a higher redox potential than a V ion or a metal ion such as a chromium ion that exhibits a lower redox potential than a V ion.

## Claims

### Claim 1

A redox flow battery performing charge and discharge by supplying a positive electrode electrolyte and a negative electrode electrolyte to a battery cell,
each of said positive electrode electrolyte and said negative electrode electrolyte containing a vanadium ion,
at least said positive electrode electrolyte further containing a divalent manganese ion higher in redox potential than the vanadium ion, and
a total concentration of said divalent manganese ion being not less than 0.1M and not more than 0.5M.

### Claim 2 (depends on 1)

The redox flow battery according to claim 1, wherein
said negative electrode electrolyte further contains a metal ion higher in redox potential than the vanadium ion, and
a total concentration of said divalent manganese ion in said positive electrode electrolyte and a total concentration of said metal ion in said negative electrode electrolyte each are not less than 0.1M and not more than 0.5M.

### Claim 3 (depends on 2)

The redox flow battery according to claim 2, wherein said metal ion higher in redox potential is at least one type of metal ions selected from a manganese ion, a lead ion, a cerium ion, and a cobalt ion.

### Claim 4 (depends on 2)

The redox flow battery according to claim 2, wherein said metal ion higher in redox potential is at least one type of manganese ions of a divalent manganese ion and a trivalent manganese ion.

### Claim 5 (depends on 2)

The redox flow battery according to claim 2, wherein the electrolyte containing said metal ion higher in redox potential contains at least one type of manganese ions of a divalent manganese ion and a trivalent manganese ion, and tetravalent manganese.

### Claim 6 (depends on 1)

The redox flow battery according to claim 1, wherein each of said positive electrode electrolyte and said negative electrode electrolyte contains a sulfate anion.

### Claim 7 (depends on 1)

The redox flow battery according to claim 1, wherein
a solvent of each of said positive electrode electrolyte and said negative electrode electrolyte is an H2SO4 aqueous solution, and
a sulfuric acid concentration of each of said positive electrode electrolyte and
said negative electrode electrolyte is not more than 5M.

### Claim 8 (depends on 1)

The redox flow battery according to claim 1, wherein said redox flow battery is operated such that a state of charge of said positive electrode electrolyte exceeds 90%.