Redox flow cell

• US 20100003586A1
• Filed: 07/01/2008
• Published: 01/07/2010
• Est. Priority Date: 07/01/2008
• Status: Active Grant

• Current Assignee: Imergy Power Systems, Inc.
• Original Assignee: Deeya Energy Incorporated A California C-Corporation
• Inventors: Sahu, Saroj Kumar
• Granted Patent: US 7,927,731 B2
• Time in Patent Office: Days
• US Class Current: 429/101
• CPC Class Codes: H01M 8/1016 characterised by the electrolyte material H01M8/12 takes precedence
• CPC Class Codes: H01M 8/188 by recharging of redox couples containing fluids; Redox flow type batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

A redox flow cell is presented that utilizes a porous membrane separating a first half cell and a second half cell. The porous membrane is chosen to have a figure of merit (FOM) is at least a minimum FOM. A method of providing a porous membrane for a flow cell can include determining a figure of merit; determining a first parameter from a pore size or a thickness for the porous membrane; determining a second parameter from the pore size or the thickness that is not the first parameter for the porous membrane, based on the figure of merit; and constructing a porous membrane having the pore size and the thickness.

Claims

1. A redox flow cell, comprising:

a first half cell having a first electrolyte;

a second half cell having a second electrolyte; and

a porous membrane separating the first half cell and the second half cell, the porous membrane having a figure-of-merit (FOM) that is at least a minimum FOM, wherein the FOM=(T²η

)/P where T is a membrane thickness, P is an average pore size of the membrane, and η

is an average viscosity of the first electrolyte and the second electrolyte.

2. The cell of claim 1, wherein the first electrolyte and the second electrolyte are both in a non-zero redox state when charged or discharged.

3. The redox flow cell of claim 1, wherein the average pore size is less than about 0.5 micron, the membrane thickness is greater than about 1.0 millimeters, and the average viscosity of the first electrolyte and the second electrolyte is about 4.0 cP.

4. The cell of claim 1, wherein the porous membrane has been post production treated to substantially remove any oil or plasticizer content.

5. The cell of claim 1, wherein the membrane has been surface treated to modify the surface contact angle with respect to the electrolyte solutions.

6. The cell of claim 1 wherein the first electrolyte includes hydrochloric acid and chlorides of iron and the second electrolyte includes hydrochloric acid and chlorides of chromium.

7. The cell of claim 1, wherein the minimum FOM is ten (10).

8. A method of providing a porous membrane for a flow cell, comprising:

determining a figure of merit;

determining a first parameter from a pore size or a thickness for the porous membrane;

determining a second parameter from the pore size or the thickness that is not the first parameter for the porous membrane, based on the figure of merit; and

constructing a porous membrane having the determined pore size and thickness.

9. The method of claim 8, wherein determining the figure of merit comprises:

defining the figure of merit as FOM=(T²η

)/P where T is the thickness, P is the pore size, and η

is an average viscosity of the electrolytes of the flow cell, and

choosing a figure of merit greater than about 10 based on a target cross-diffusion current when the porous membrane is utilized in the flow cell