US4576878A
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Method and apparatus for rebalancing a redox flow cell system
Assignee: UNITED STATES NASA THE, Administrator of
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Filing: 1985-06-25
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Granted: 1986-03-18
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Expires: 2005-06-25
Abstract
Abstract A rebalance cell is provided for a REDOX electrochemical system of the type having anode and cathode fluids which are aqueous HCl solutions with two metal species in each. The rebalance cell has a cathode compartment and a chlorine compartment separated by an ion permeable membrane. By applying an electrical potential to the rebalance cell while circulating cathode fluid through the cathode compartment and while circulating an identical fluid through the chlorine compartment, any significant imbalance of the REDOX system is prevented.
Inventors
- 👤 Randall F. Gahn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 02:37
CPC Classifications
H; H01; H01M; H01M10/00; H01M10/42; H01M50/00; H01M50/70; H01M50/77; Y; Y02; Y02E; Y02E60/00; Y02E60/10
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
182 words
In a REDOX system including a REDOX cell having an anode chamber and a cathode chamber separated by an ion exchange membrane with an inert electrode in each chamber and anode and cathode fluids each of which includes the same two species of metal chlorides in aqueous HCl, the active metal ions in each fluid being determined by the charging voltage applied between the electrodes of the REDOX cell, the improvement comprising: a rebalance cell having a cathode chamber and a chlorine reactant chamber separated by an ion permeable membrane with an inert electrode in each chamber; means for directing the cathode fluid of the REDOX cell through the cathode chamber of the rebalance cell; a supply of reactant fluid comprised of said two species of metal chlorides in aqueous HCl; means for circulating said reactant fluid through said reactant chamber while said electrode in said reactant chamber is negative with respect to said electrode in the cathode chamber whereby the active metal ions in the cathode chamber are reduced while chlorine ions in the reactant chamber are oxidized to chlorine gas.
Claim 2
Dependent Claim
182 words
In a REDOX system including a REDOX cell having an anode chamber and a cathode chamber separated by an ion exchange membrane with an inert electrode in each chamber and anode and cathode fluids each of which includes the same two species of metal chlorides in aqueous HCl, the active metal ions in each fluid being determined by the charging voltage applied between the electrodes of the REDOX cell, the improvement comprising: a rebalance cell having a cathode chamber and a chlorine reactant chamber separated by an ion permeable membrane with an inert electrode in each chamber; means for directing the cathode fluid of the REDOX cell through the cathode chamber of the rebalance cell; a supply of reactant fluid comprised of said two species of metal chlorides in aqueous HCl; means for circulating said reactant fluid through said reactant chamber while said electrode in said reactant chamber is negative with respect to said electrode in the cathode chamber whereby the active metal ions in the cathode chamber are reduced while chlorine ions in the reactant chamber are oxidized to chlorine gas.
Claim 3
Dependent Claim
23 words
The system of claim 1 wherein the two metal species in the anode, cathode and reactant fluids are iron chloride and chromium chloride.
Claim 4
Dependent Claim
18 words
The system of claim 2 wherein said anode, cathode and reactant fluids are 3 N aqueous HCl solutions.
Claim 5
Dependent Claim
21 words
The system of claim 3 wherein the iron ions and the chromium ions are each present in a 1 molar concentration.
Claim 6
Dependent Claim
12 words
The system of claim 1 wherein the electrodes are carbon felt material.
Claim 7
Dependent Claim
25 words
The system of claim 1 wherein the electrode in the chlorine chamber of the rebalance cell is in direct contact with the ion permeable membrane.
Claim 8
Dependent Claim
14 words
The system of claim 1 wherein said anode, cathode and reactant fluids contain bismuth.
Claim 9
Dependent Claim
17 words
The system of claim 1 wherein said ion permeable membrane of the rebalance cell is cation permeable.
Claim 10
Independent Claim
129 words
A method of rebalancing the charge in the anode and cathode fluids of a REDOX cell of the type having the same two metal ion species in each of said fluids, the fluids being aqueous HCl, comprising the steps of: providing a rebalance cell separated into a cathode chamber and a chlorine chamber by an ion permeable membrane; passing said cathode fluid through said cathode chamber; providing a supply of aqueous HCl reactant fluid containing the same metal ion species as the anode and cathod fluids; and passing said reactant fluid through said chlorine chamber while supplying electrons thereto and simultaneously removing electrons from said cathode fluid whereby active metal ions are reduced in the cathode chamber and chlorine ions are oxidized to chlorine gas in the chlorine chamber.
Claim 11
Independent Claim
129 words
A method of rebalancing the charge in the anode and cathode fluids of a REDOX cell of the type having the same two metal ion species in each of said fluids, the fluids being aqueous HCl, comprising the steps of: providing a rebalance cell separated into a cathode chamber and a chlorine chamber by an ion permeable membrane; passing said cathode fluid through said cathode chamber; providing a supply of aqueous HCl reactant fluid containing the same metal ion species as the anode and cathod fluids; and passing said reactant fluid through said chlorine chamber while supplying electrons thereto and simultaneously removing electrons from said cathode fluid whereby active metal ions are reduced in the cathode chamber and chlorine ions are oxidized to chlorine gas in the chlorine chamber.
Claim 12
Dependent Claim
19 words
The method of claim 9 wherein one of said two metal ion species in the cathode fluid is iron.
Claim 13
Dependent Claim
21 words
The method of claim 9 wherein the anode, cathode and reactant fluids contain trace amounts of bismuth or bismuth and lead.
Claim 14
Dependent Claim
13 words
The method of claim 9 wherein said ion permeable membrane is cation permeable.
Claim 15
Dependent Claim
15 words
The method of claim 9 wherein said two metal ion species are iron and chromium.
Claim 16
Dependent Claim
16 words
The method of claim 13 wherein the anode, cathode and reactant fluids are 3 normal HCl.
Claim 17
Dependent Claim
20 words
The method of claim 14 wherein said iron and chromium species are present in a 1 molar concentration of each.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-03-17 | 1989-09-16 | 1990-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-17 | 1993-09-16 | 1994-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-17 | 1997-09-16 | 1998-03-18 | $7700.00 | Window Closed / Lapsed |