Reactivation of flow battery electrode by exposure to oxidizing solution

Patent metadata

Field	Value
Publication number	US-2016013505-A1
Application number	US-201314770969-A
Country	US
Kind code	A1
Filing date	Mar 15, 2013
Priority date	Mar 15, 2013
Publication date	Jan 14, 2016
Grant date	—

Abstract

A flow battery includes at least a cell that has a first electrode, a second electrode and an electrolyte separator layer arranged between the electrodes. A supply/storage system is external of the cell and includes a first vessel fluidly connected in a first loop with the first electrode and a second vessel fluidly connected in a second loop with the second electrode. The first loop and the second loop are isolated from each other. The supply/storage system is configured to fluidly connect the first loop and the second loop to move a second liquid electrolyte from the second vessel into a first liquid electrolyte in the first vessel responsive to a half-cell potential at the first electrode being less than a defined threshold half-cell potential.

First claim

What is claimed is:

1 . A flow battery comprising:
at least one cell including a first electrode, a second electrode spaced apart from the first electrode, and an electrolyte separator layer arranged between the first electrode and the second electrode; and a supply/storage system external of the at least one cell and including:
a first vessel fluidly connected in a first loop with the first electrode,
a second vessel fluidly connected in a second loop with the second electrode, the first loop and the second loop being isolated from each other with respect to open fluid flow there between, and
the supply/storage system being configured to fluidly connect the first loop and the second loop to move a second liquid electrolyte from the second vessel into a first liquid electrolyte in the first vessel responsive to a half-cell potential at the first electrode being less than a defined threshold half-cell potential.

2 . The flow battery as recited in claim 1 , wherein the supply/storage system includes a feed line between the first vessel and the second vessel.

3 . The flow battery as recited in claim 1 , wherein the first electrode is a negative electrode.

4 . The flow battery as recited in claim 1 , further comprising a reference electrode configured to determine the half-cell potential of the first electrode.

5 . The flow battery as recited in claim 1 , wherein the defined threshold half-cell potential is a difference between a a half-cell potential taken during operation of the flow battery| [MLK1] and a half-cell potential taken at open circuit.

6 . The flow battery as recited in claim 1 , wherein the supply/storage system includes at least one fluid level sensor and at least one concentration sensor configured to detect, respectively, a level of the first liquid electrolyte in the first vessel and a concentration of the first liquid electrolyte in the first vessel.

7 . The flow battery as recited in claim 1 , wherein an active area of the at least one cell is symmetrical with respect to the electrolyte separator layer.

8 . The flow battery as recited in claim 7 , wherein the first electrode and the second electrode include respective vertical mid-lines about which the first electrode and the second electrode are also symmetrical.

9 . The flow battery as recited in claim 7 , wherein the flow of the second loop is configured to be re-directed to the first electrode and the flow of the first loop is configured to be re-directed to the second electrode after a defined period of operation.

10 . The flow battery as recited in claim 1 , wherein the first electrode is a negative electrode and the second electrode is a positive electrode, and the supply/storage system is configured to be changed such that the first electrode becomes the positive electrode and the second electrode becomes the negative electrode, responsive to a defined time period of operation of the at least one cell.

11 . A method of operating a flow battery, the method comprising:
balancing amounts of a first fluid electrolyte and a second fluid electrolyte in a flow battery in response to the half-cell potential on the first side being less than a defined threshold half-cell potential.

12 . The method as recited in claim 11 , wherein the balancing includes mixing the second liquid electrolyte from a second vessel of the flow battery into the first liquid electrolyte in a first vessel of the flow battery in response to the half-cell potential of the first electrode being less than the defined threshold half-cell potential.

13 . The method as recited in claim 10 , wherein the first electrode is a negative electrode.

14 . The method as recited in claim 10 , further comprising activating the first electrode in-situ by exposing the first electrode to an oxidizing fluid to reactivate the first electrode.

15 . The method as recited in claim 14 , wherein the oxidizing fluid is a positive liquid electrolyte of the flow battery.

16 . The method as recited in claim 14 , including, prior to the exposing of the first electrode to the oxidizing fluid, draining the first electrode of a negative liquid electrolyte.

17 . The method as recited in claim 11 , including determining the half-cell potential at the first electrode using a reference electrode.

18 . The method as recited in claim 10 , wherein the defined threshold half-cell potential is a difference between a half-cell potential taken during operation of the flow battery and a half-cell potential taken at open circuit and.

19 . The method as recited in claim 10 , wherein the flow battery includes at least one cell having the first electrode, a second electrode spaced apart from the first electrode, and an electrolyte separator layer arranged between the first electrode and the second electrode, further including swapping a flow of the first liquid electrolyte and the second liquid electrolyte through the at least one cell in response to a defined time period of operation of the at least one cell.

20 . The method as recited in claim 10 , wherein the flow battery includes at least one cell having the first electrode, a second electrode spaced apart from the first electrode, and an electrolyte separator layer arranged between the first electrode and the second electrode, the first fluid electrolyte initially being a negative electrolyte and the second fluid electrolyte initially being a positive electrolyte, further including reversing a polarity of the at least one cell and charging the flow battery to convert the positive electrolyte to negative electrolyte and the negative electrolyte to positive electrolyte without changing the pumping configuration.

21 . A flow battery comprising:
at least one cell including a first electrode, a second electrode spaced apart from the first electrode, and an electrolyte separator layer arranged between the first electrode and the second electrode; and a supply/storage system external of the at least one cell and including:
a first vessel fluidly connectable in a first loop with each of the first electrode and the second electrode, and
a second vessel fluidly connectable in a second loop with each of the first electrode and the second electrode,
the supply/storage system including a first configuration in which the first vessel is fluidly connected in the first loop with the first electrode and the second vessel is fluidly connected in the second loop with the second electrode and a second configuration in which the first vessel is fluidly connected in the first loop with the second electrode and the second vessel is fluidly connected in the second loop with the first electrode.

22 . The flow battery as recited in claim 21 , wherein the first electrode and the second electrode include respective vertical mid-lines about which the first electrode and the second electrode are also symmetrical.

23 . The flow battery as recited in claim 21 , wherein switching between the first configuration and the second configuration is responsive to a defined time period of operation of the flow battery.

24 . The flow battery as recited in claim 21 , wherein the first electrode is a negative electrode and the second electrode is a positive electrode.

Assignees

• United Technologies Corp

Inventors

• Darling Robert Mason
• Zaffou Rachid
• Perry Michael L
• Walker Craig R

Classifications

• 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

• Y02E60/50

  Fuel cells · CPC title