Mitigation of parasitic reactions within flow batteries

Patent metadata

Field	Value
Publication number	US-2016308224-A1
Application number	US-201615090506-A
Country	US
Kind code	A1
Filing date	Apr 4, 2016
Priority date	Apr 15, 2015
Publication date	Oct 20, 2016
Grant date	—

Abstract

Productive electrochemical reactions can often occur most effectively in proximity to a separator dividing an electrochemical cell into two half-cells. Parasitic reactions can often occur at locations more removed from the separator. Parasitic reactions are generally undesirable in flow batteries and other electrochemical systems, since they can impact operating performance. Flow batteries having a decreased incidence of parasitic reactions can include, a first half-cell containing a first electrode, a second half-cell containing a second electrode, a separator disposed between the first half-cell and the second half-cell and contacting the first and second electrodes, a first bipolar plate contacting the first electrode, and a second bipolar plate contacting the second electrode, where a portion of the first electrode or the first bipolar plate contains a dielectric material. The first electrode and the first bipolar plate still define a contiguous electrically conductive pathway when containing the dielectric material.

First claim

What is claimed is the following:

1 . A flow battery comprising:
a first half-cell containing a first electrode; a second half-cell containing a second electrode; a separator disposed between the first half-cell and the second half-cell;
wherein the first electrode and the second electrode overlay and contact opposing faces of the separator; and
a first bipolar plate overlaying and contacting the first electrode and a second bipolar plate overlaying and contacting the second electrode;
wherein a portion of the first electrode or the first bipolar plate contains a dielectric material, but such that the first electrode and the first bipolar plate collectively define a contiguous electrically conductive pathway within the first half-cell.

2 . The flow battery of claim 1 , wherein an internal portion of the first electrode or an internal portion of the first bipolar plate is infused with the dielectric material.

3 . The flow battery of claim 2 , wherein the internal portion of the first electrode is infused with the dielectric material;
wherein the dielectric material is not in contact with the separator or the first bipolar plate.

4 . The flow battery of claim 2 , wherein the internal portion of the first bipolar plate is infused with the dielectric material;
wherein the dielectric material is not in contact with the first electrode.

5 . The flow battery of claim 4 , wherein the first bipolar plate comprises a plurality of channels that are at least partially coated with the dielectric material.

6 . The flow battery of claim 1 , wherein the first bipolar plate comprises a plurality of conductive posts extending through the dielectric material and contacting the first electrode.

7 . The flow battery of claim 1 , wherein the first electrode comprises a conductive mesh having a conductive medium deposited on a first side of the conductive mesh and the dielectric material deposited on a second side of the conductive mesh, the conductive medium being in contact with the separator and the dielectric material being in contact with the first bipolar plate;
wherein a plurality of conductive posts extend through the dielectric material from the conductive mesh to the first bipolar plate.

8 . The flow battery of claim 1 , wherein the first electrode is a negative electrode.

9 . A flow battery comprising:
a first half-cell containing a first electrode; a second half-cell containing a second electrode; and a separator disposed between the first half-cell and the second half-cell;
wherein the first electrode and the second electrode overlay and contact opposing faces of the separator; and
wherein the first electrode has a thickness of about 100 microns or less.

10 . The flow battery of claim 9 , wherein the first electrode has an active area sized such that a ratio of productive reactions to parasitic reactions exceeds about 10 when the flow battery is in operation.

11 . The flow battery of claim 9 , wherein the first electrode comprises a catalyst layer coated upon the separator.

12 . The flow battery of claim 11 , wherein the catalyst layer comprises a plurality of carbon nanotubes.

13 . The flow battery of claim 9 , further comprising:
a first bipolar plate overlaying and contacting the first electrode and a second bipolar plate overlaying and contacting the second electrode.

14 . The flow battery of claim 9 , wherein the first electrode is a negative electrode.

15 . A method comprising:
forming an electrochemical cell comprising:
a first half-cell containing a first electrode;
a second half-cell containing a second electrode;
a separator disposed between the first half-cell and the second half-cell;
wherein the first electrode and the second electrode overlay and contact opposing faces of the separator; and

a first bipolar plate overlaying and contacting the first electrode and a second bipolar plate overlaying and contacting the second electrode; and
incorporating a dielectric material in a portion of the first electrode or the first bipolar plate, but such that the first electrode and the first bipolar plate collectively define a contiguous electrically conductive pathway within the first half-cell.

16 . The method of claim 15 , wherein a portion of the first electrode contains the dielectric material, incorporating the dielectric material comprising infusing the dielectric material into an internal portion of the first electrode;
wherein the dielectric material is not in contact with the separator or the first bipolar plate.

17 . The method of claim 15 , wherein a portion of the first bipolar plate contains the dielectric material, incorporating the dielectric material comprising infusing the dielectric material into an internal portion of the first bipolar plate;
wherein the dielectric material is not in contact with the first electrode.

18 . The method of claim 17 , wherein the dielectric material is infused into a plurality of channels within the dielectric material, the channels being coated with the dielectric material.

19 . The method of claim 15 , wherein the dielectric material is incorporated by spraying a solution of the dielectric material onto the first electrode or the first bipolar plate.

20 . The method of claim 15 , wherein the first bipolar plate comprises a plurality of conductive posts extending through the dielectric material, the conductive posts contacting the first electrode.

21 . The method of claim 15 , wherein the first electrode comprises a conductive mesh having a conductive medium deposited on a first side of the conductive mesh and the dielectric material deposited on a second side of the conductive mesh, the conductive medium being in contact with the separator and the dielectric material being in contact with the first bipolar plate;
wherein a plurality of conductive posts extend through the dielectric material from the conductive mesh to the first bipolar plate.

22 . A method comprising:
providing a separator; depositing a catalyst layer upon at least a first face of the separator; and forming a flow battery having the catalyst layer in contact with a bipolar plate in a at least a first half-cell of the flow battery.

23 . The method of claim 22 , wherein the catalyst layer comprises a plurality of carbon nanotubes.

Assignees

• Lockheed Martin Advanced Energy Storage Llc

Inventors

• Morris-Cohen Adam
• Puranam Srivatsava
• Goeltz John
• Esswein Arthur J

Classifications

• H01M8/0228 Primary

  in the form of layered or coated products · CPC title

• H01M4/96

  Carbon-based electrodes · CPC title

• H01M8/0258 Primary

  characterised by the configuration of channels, e.g. by the flow field of the reactant or coolant · CPC title

• H01M8/188

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

• Y02E60/50

  Fuel cells · CPC title