Electrolyte balancing strategies for flow batteries

Patent metadata

Field	Value
Publication number	US-10249897-B2
Application number	US-201415025225-A
Country	US
Kind code	B2
Filing date	Sep 24, 2014
Priority date	Sep 25, 2013
Publication date	Apr 2, 2019
Grant date	Apr 2, 2019

Abstract

The present invention is directed to a redox flow battery comprising at least one electrochemical cell in fluid communication with a balancing cell, said balancing cell comprising: a first and second half-cell chamber, wherein the first half-cell chamber comprises a first electrode in contact with a first aqueous electrolyte of the redox flow battery; and wherein the second half-cell chamber comprises a second electrode in contact with a second aqueous electrolyte, said second electrode comprising a catalyst for the generation of O2.

First claim

What is claimed:

1. A redox flow battery comprising at least one electrochemical cell in fluid communication with a balancing cell, said balancing cell comprising:
first and second half-cell chambers separated by a membrane,
wherein the first half-cell chamber comprises a first electrode in contact with a first aqueous electrolyte of the redox flow battery; and
wherein the second half-cell chamber comprises a second electrode in contact with a second aqueous electrolyte, said second electrode comprising a catalyst for the generation of O 2 ; and wherein the second aqueous electrolyte has a pH from 2 to 7.

2. A balancing cell comprising:
first and second half-cell chambers
separated by a membrane,
wherein the first half-cell chamber comprises a first electrode in contact with a first aqueous electrolyte of an electrochemical cell of a redox flow battery; and
wherein the second half-cell chamber comprises a second electrode in contact with a second aqueous electrolyte, said second electrode comprising a catalyst for the generation of O 2; and wherein the second aqueous electrolyte has a pH from 2 to 7.

3. The flow battery of claim 1 , wherein the first aqueous electrolyte comprises a negative working electrolyte of the redox flow battery.

4. The flow battery of claim 1 , wherein the first aqueous electrolyte has a pH in a range of from about 9 to about 14.

5. The flow battery of claim 1 , wherein the first and second aqueous electrolytes each have a pH whose difference is less than about 7.

6. The flow battery of claim 1 , further comprising a porous medium located near or adjacent to the membrane in the first half-cell chamber.

7. The flow battery of claim 1 , wherein the membrane comprises a sulfonated perfluorinated polymer or co-polymer.

8. The flow battery of claim 7 , wherein the membrane comprises a sulfonated perfluorinated polymer or co-polymer of tetrafluoroethylene, optionally comprising perfluorovinyl ether.

9. The flow battery of claim 1 , wherein the membrane comprises an ionomer membrane.

10. The flow battery of claim 9 , wherein the ionomer membrane comprises a short side chain (SSC) copolymer of tetrafluoroethylene and a sulfonyl fluoride vinyl ether (SFVE) F 2 C═CF—O—CF 2 CF 2 —SO 2 F.

11. The flow battery of claim 10 , wherein the ionomer membrane is modified by precipitating particles therewithin, the particles comprising a metal, metal oxide, organometallic, polymeric material, or a combination thereof.

12. The flow battery of claim 1 , wherein the membrane comprises a bipolar membrane.

13. The flow battery of claim 12 , wherein the bipolar membrane comprises at least one cation exchange ionomer membrane and one anion exchange ionomer membrane.

14. The flow battery of claim 13 , wherein the bipolar membrane further comprises a metal oxide film sandwiched between the at least one cation exchange ionomer membrane and one anion exchange ionomer membrane, the metal oxide film being capable of catalyzing the dissociation of water upon the application of an electric potential thereto.

15. The flow battery of claim 1 , wherein the second electrode comprises a catalyst suitable for the electrochemical generation of oxygen from water.

16. The flow battery of claim 15 , wherein catalyst comprises a metal oxide.

17. The flow battery of claim 16 , wherein the metal oxide comprises an oxide of cobalt, iridium, iron, manganese, nickel, ruthenium, indium, tin, or a combination thereof.

18. The flow battery of claim 17 , wherein the second electrode comprises an oxide of iridium, an oxide of nickel, or an oxide of a nickel-iron alloy.

19. The flow battery of claim 15 , wherein the catalyst comprises an allotrope of carbon.

20. The flow battery of claim 3 , wherein the negative working electrolyte of the flow battery comprises a compound comprising Al, Ca, Ce, Co, Cr, Fe, Mg, Mn, Mo, Si, Sn, Ti, V, W, Zn, or Zr.

21. The flow battery of claim 20 , wherein the negative working electrolyte of the flow battery comprises a coordination compound of titanium.

22. The flow battery of claim 1 , wherein at least the first half-cell chamber and optionally the second half-cell chamber is configured as a flow-through cell.

23. An energy storage system comprising the flow battery of claim 1 .

Assignees

• Lockheed Martin Energy Llc

Inventors

• Reece Steven Y
• Badrinarayanan Paravastu
• Tyagi Nitin
• Grejtak Timothy B

Classifications

• H01M8/1051

  Non-ion-conducting additives, e.g. stabilisers, SiO2 or ZrO2 · CPC title

• H01M8/20

  Indirect fuel cells, e.g. fuel cells with redox couple being irreversible (H01M8/18 takes precedence) · CPC title

• H01M8/1039

  halogenated, e.g. sulfonated polyvinylidene fluorides · CPC title

• H01M8/1053

  consisting of layers of polymers with at least one layer being ionically conductive · CPC title

• H01M8/188 Primary

  by recharging of redox couples containing fluids; Redox flow type batteries · CPC title