Method and system for rebalancing electrolytes in a redox flow battery system

Patent metadata

Field	Value
Publication number	US-11527771-B2
Application number	US-202117151611-A
Country	US
Kind code	B2
Filing date	Jan 18, 2021
Priority date	Jun 7, 2013
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

A method of rebalancing electrolytes in a redox flow battery system comprises directing hydrogen gas generated on the negative side of the redox flow battery system to a catalyst surface, and fluidly contacting the hydrogen gas with an electrolyte comprising a metal ion at the catalyst surface, wherein the metal ion is chemically reduced by the hydrogen gas at the catalyst surface, and a state of charge of the electrolyte and pH of the electrolyte remain substantially balanced.

First claim

The invention claimed is:

1. A redox flow battery system, comprising:
a redox flow battery cell, and
a catalyst bed positioned in a rebalancing reactor fluidly coupled to the redox flow battery cell, the catalyst bed including,
a substrate layer, a spacing layer, and a catalyst layer interposed between and attached to the substrate layer and the spacing layer to form a one-piece removable catalyst bed; and
a controller comprising computer-readable instructions stored on non-transitory memory thereof that when executed enable the controller to:
eject hydrogen gas from a gas head space of a positive electrolyte source via a first ejector in response to a negative electrolyte flowing through the first ejector; and
eject hydrogen gas from a gas head space of a negative electrolyte source via a second ejector in response to a positive electrolyte flowing through the second ejector.

2. The redox flow battery system of claim 1 , wherein sizes of the first ejector and the second ejector are based on a desired hydrogen gas flow rate to a first trickle bed reactor and a second trickle bed reactor.

3. The redox flow battery system of claim 2 , wherein the first trickle bed reactor is arranged along a positive electrolyte flow path from a first pump to a positive electrode compartment.

4. The redox flow battery system of claim 2 , wherein the second trickle bed reactor is arranged along a negative electrolyte flow path from a second pump to a negative electrode compartment.

5. The redox flow battery system of claim 1 , further comprising an external source of hydrogen gas, wherein the external source is configured to supply hydrogen gas to the positive electrolyte source and the negative electrolyte source.

6. The redox flow battery system of claim 5 , where the external source of hydrogen gas is further configured to supply hydrogen gas to inlets of one or more of a first trickle bed reactor and a second trickle bed reactor.

7. The redox flow battery system of claim 6 , wherein the instructions further enable the controller to control a flow of hydrogen gas from the external source in response to a gas leak being detected.

8. The redox flow battery system of claim 6 , wherein the instructions further enable the controller to control a flow of hydrogen gas from the external source in response to a reduction reaction rate being less than a threshold rate at a hydrogen partial pressure less than a threshold partial pressure.

9. The redox flow battery system of claim 6 , wherein the instructions further enable the controller to control a flow of hydrogen gas from the external source in response to a measured change in pH, wherein the measured change includes a pH increasing above a first threshold or decreasing below a second threshold.

10. A redox flow battery system, comprising:
a redox flow battery cell, and
a catalyst bed positioned in a rebalancing reactor fluidly coupled to the redox flow battery cell, the catalyst bed including,
a substrate layer, a spacing layer, and a catalyst layer interposed between and attached to the substrate layer and the spacing layer to form a one-piece removable catalyst bed; and
a controller comprising computer-readable instructions stored on non-transitory memory thereof that when executed enable the controller to:
adjust a hydrogen gas flow from an external source to one or more of a positive electrolyte source, a negative electrolyte source, a first trickle bed reactor, and a second trickle bed reactor.

11. The redox flow battery system of claim 10 , wherein the instructions further enable the adjust the hydrogen gas flow from the external source to the negative electrolyte source in response to the pH increasing beyond a first threshold pH or decreasing beyond a second threshold pH.

12. The redox flow battery system of claim 11 , wherein the instructions further enable the controller to increase the hydrogen gas flow in response to the pH being greater than the first threshold pH.

13. The redox flow battery system of claim 10 , wherein the instructions further enable the controller to adjust the hydrogen gas flow from the external source in response to a change in electrolyte pH or a change in electrolyte state of charge detected by an oxygen-reduction potential meter or an optical sensor.

14. The redox flow battery system of claim 10 , the instructions further enable the controller to adjust the hydrogen gas flow from the external source in response to a change in pH or a change in state of charge of an electrolyte over a predetermined amount of time.

15. The redox flow battery system of claim 14 , wherein the predetermined amount of time is based on one more of a recirculation rate and changes in concentration due to side reactions or leaks.

16. The redox flow battery system of claim 15 , wherein the predetermined amount of time is reduced in response to the recirculation rate increasing.

17. A redox flow battery, comprising:
a redox flow battery cell, and
a catalyst bed positioned in a rebalancing reactor fluidly coupled to the redox flow battery cell, the catalyst bed including,
a substrate layer, a spacing layer, and a catalyst layer interposed between and attached to the substrate layer and the spacing layer to form a one-piece removable catalyst bed, wherein the one-piece removable catalyst bed is arranged in a reactor vessel comprising a higher aspect ratio reactor shape, wherein a length to diameter ratio is greater than a threshold ratio.

18. The redox flow battery of claim 17 , wherein the reactor vessel is free of interior baffling.

19. The redox flow battery of claim 17 , wherein the spacing layer separates successive substrate and catalyst layers wound into a jelly roll structure, wherein the spacing layer comprises a plastic mesh.

20. The redox flow battery of claim 17 , wherein a thickness or a porosity of the spacing layer is increased in response to a pressure drop across the reactor vessel.

Assignees

• Ess Technology Inc

Inventors

• Song Yang
• Evans Craig E

Classifications

• Y02E60/50

  Fuel cells · CPC title

• H01M8/20

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

• H01M8/188 Primary

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

• H01M8/004

  Cylindrical, tubular or wound · CPC title

• H01M8/0693

  Treatment of the electrolyte residue, e.g. reconcentrating · CPC title