Method and system to modify the performance of a redox flow battery

Patent metadata

Field	Value
Publication number	US-2020136161-A1
Application number	US-201816171542-A
Country	US
Kind code	A1
Filing date	Oct 26, 2018
Priority date	Oct 26, 2018
Publication date	Apr 30, 2020
Grant date	—

Abstract

According to one embodiment of the present disclosure, a redox flow battery is provided comprising an ionically conductive separator, a working side flowing electrolyte, a working electrode in ionic contact with the working side of the ionically conductive separator and the working side flowing electrolyte, a counter electrode, and an auxiliary electrode peripherally circumscribed by the working electrode in a common layer of the flow battery. The auxiliary electrode is in ionic contact with the working electrode, an electrically insulating peripheral gap separates the auxiliary electrode from the working electrode. A working electrode terminal is conductively coupled to the working electrode, an auxiliary electrode terminal is conductively coupled to the auxiliary electrode, and a counter electrode terminal is conductively coupled to the counter electrode. An auxiliary power source is configured to establish an auxiliary circuit voltage differential between the counter electrode terminal and the auxiliary electrode terminal, control an auxiliary electrode voltage such that the auxiliary electrode voltage is within an electrochemical window of the working side flowing electrolyte, and establish a voltage differential between the working electrode terminal and the auxiliary electrode terminal. A method of operation of the redox flow battery is further provided

First claim

What is claimed is:

1 . A redox flow battery comprising:
an ionically conductive separator comprising a working side and a counter side; a working side flowing electrolyte; a working electrode in ionic contact with the working side of the ionically conductive separator and the working side flowing electrolyte; a counter side flowing electrolyte; a counter electrode in ionic contact with the counter side of the ionically conductive separator and the counter side flowing electrolyte; an auxiliary electrode peripherally circumscribed by the working electrode in a common layer of the flow battery, wherein the auxiliary electrode is in ionic contact with the working electrode, the working side flowing electrolyte, and the working side of the ionically conductive separator; an electrically insulating peripheral gap separating the auxiliary electrode from the working electrode; a working electrode terminal conductively coupled to the working electrode; an auxiliary electrode terminal conductively coupled to the auxiliary electrode; a counter electrode terminal conductively coupled to the counter electrode; and an auxiliary power source electrically connected to the auxiliary electrode terminal and the counter electrode terminal, wherein the auxiliary power source is configured to
establish an auxiliary circuit voltage differential between the counter electrode terminal and the auxiliary electrode terminal,
control an auxiliary electrode voltage such that the auxiliary electrode voltage is within an electrochemical window of the working side flowing electrolyte, and
establish a voltage differential between the working electrode terminal and the auxiliary electrode terminal.

2 . The redox flow battery of claim 1 , wherein the working side flowing electrolyte comprises an aqueous acidic solution and the auxiliary electrode voltage is less than 1.23 Volts (V) vs a standard hydrogen electrode (SHE).

3 . The redox flow battery of claim 1 , wherein the auxiliary power source is configured such that a ratio of a boosted power circuit current minus a conventional power circuit current to auxiliary circuit current is greater than 1:1, when the auxiliary power source is activated.

4 . The redox flow battery of claim 1 , wherein the auxiliary power source is configured such that a ratio of a boosted power circuit current minus a conventional power circuit current to auxiliary circuit current is greater than 10:1, when the auxiliary power source is activated.

5 . The redox flow battery of claim 1 , wherein the auxiliary power source is configured such that a ratio of a boosted power circuit power minus a conventional power circuit power to auxiliary circuit power is greater than 1:1, when the auxiliary power source is activated.

6 . The redox flow battery of claim 1 , wherein the working electrode is substantially free of metallic electro-catalysts.

7 . The redox flow battery of claim 1 , wherein the ionically conductive separator, the working electrode, the counter electrode, and the auxiliary electrode comprise a substantially planar geometry.

8 . The redox flow battery of claim 1 , wherein the ionically conductive separator, the working electrode, the counter electrode, and the auxiliary electrode comprise a substantially cylindrical geometry.

9 . The redox flow battery of claim 1 , wherein the respective total surface areas of the working electrode and the auxiliary electrode define a working electrode to auxiliary electrode surface area ratio of at least 5:1.

10 . The redox flow battery of claim 1 , wherein the respective total surface areas of the working electrode and the auxiliary electrode define a working electrode to auxiliary electrode surface area ratio of between 5:1 and 100:1.

11 . The redox flow battery of claim 1 , wherein:
the working electrode defines a circular geometry comprising a working electrode inside diameter, a working electrode outside diameter, and a working electrode surface area defined between the working electrode inside diameter and the working electrode outside diameter; the auxiliary electrode defines a circular geometry comprising an auxiliary electrode outside diameter circumscribing an auxiliary electrode surface area; and the electrically insulating peripheral gap comprises an annular region between the working electrode inside diameter and the auxiliary electrode outside diameter.

12 . The redox flow battery of claim 1 wherein the electrically insulating border gap has a thickness of between 5 mm and 0.001 mm, and
the electrically insulating border gap comprises an electrically insulating material.

13 . The redox flow battery of claim 1 , wherein the working side flowing electrolyte comprises an aqueous acidic solution.

14 . The redox flow battery of claim 1 , wherein the working side flowing electrolyte has a conductivity of at least 0.045 Siemens per centimeter.

15 . The redox flow battery of claim 1 , wherein the working side flowing electrolyte comprises one or more of vanadium, iron, chromium, bromine, chlorine, sulfuric acid, hydrochloric acid, redox active organic chemicals, zinc, lithium, and aluminum.

16 . The redox flow battery of claim 1 , wherein the working side flowing electrolyte comprises vanadium chloride and hydrochloric acid.

17 . The redox flow battery of claim 1 , wherein the counter side flowing electrolyte comprises one or more of vanadium, iron, chromium, bromine, chlorine, sulfuric acid, hydrochloric acid, redox active organic chemicals, zinc, lithium, and aluminum.

18 . The redox flow battery of claim 1 , wherein the counter side flowing electrolyte comprises iron chloride and hydrochloric acid.

19 . The redox flow battery of claim 1 , wherein the redox flow battery is structurally configured such that the working side flowing electrolyte and the counter side flowing electrolyte are only in ionic communication through the ionically conductive separator.

20 . A method of operating a redox flow battery comprising
a working side flowing electrolyte; a working electrode in ionic contact with the working side of the ionically conductive separator and the working side flowing electrolyte; a counter side flowing electrolyte; a counter electrode in ionic contact with the counter side of the ionically conductive separator and the counter side flowing electrolyte; an auxiliary electrode peripherally circumscribed by the working electrode in a common layer of the flow battery, wherein the auxiliary electrode is in ionic contact with the working electrode, the working side flowing electrolyte, and the working side of the ionically conductive separator; an electrically insulating peripheral gap separating the auxiliary electrode from the working electrode; a working electrode terminal conductively coupled to the working electrode; an auxiliary electrode terminal conductively coupled to the auxiliary electrode; a counter electrode terminal conductively coupled to the counter electrode; a working electrical circuit structured to provide an electrical connection between the working electrode terminal and the counter electrode terminal; an auxiliary circuit structured to provide an electrical connection between the auxiliary electrode terminal and the counter electrode terminal; and an auxiliary power source configured to apply a subthreshold voltage across the auxiliary circuit; the method comprising: passing the working side flowing electrolyte across the working electrode and the auxiliary electrode, pass

Assignees

• Saudi Arabian Oil Co

Inventors

• Hammad Ahmad D
• Souentie Stamatios
• Alsuhaibani Abdulrahman
• Amr Issam T

Classifications

• H01M8/04873 Primary

  of the individual fuel cell · CPC title

• H01M2300/0005

  Acid electrolytes · CPC title

• H01M8/18 Primary

  Regenerative fuel cells, e.g. redox flow batteries or secondary fuel cells · CPC title

• H01M8/188 Primary

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

• H01M8/04925

  Power, energy, capacity or load · CPC title