US4761348A
Expired / Lapsed
US
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Electrolytic cell stack with molten electrolyte migration control
Assignee: United States Department of Energy
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Filing: 1987-03-17
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Granted: 1988-08-02
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Expires: 2007-03-17
Abstract
Abstract An electrolytic cell stack includes inactive electrolyte reservoirs at the upper and lower end portions thereof. The reservoirs are separated from the stack of the complete cells by impermeable, electrically conductive separators. Reservoirs at the negative end are initially low in electrolyte and the reservoirs at the positive end are high in electrolyte fill. During stack operation electrolyte migration from the positive to the negative end will be offset by the inactive reservoir capacity. In combination with the inactive reservoirs, a sealing member of high porosity and low electrolyte retention is employed to limit the electrolyte migration rate.
Inventors
- 👤 H. Russell Kunz
- 👤 Robin J. Guthrie
- 👤 Murray Katz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:30
CPC Classifications
H; H01; H01M; H01M8/00; H01M8/24; H01M8/241; H01M8/244; H01M8/14; H01M2008/147; H01M2300/00; H01M2300/0017; H01M2300/0048; H01M2300/0051; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/50
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
341 words
In an electrolytic cell stack including a plurality of electrolytic cells with electrically conductive, electrolyte impermeable separator sheets between adjacent cells in said stack, the electrolytic cells including a porous anode member, a porous cathode member and a porous matrix for molten electrolyte disposed in the stack between major surfaces of the anode and cathode members, said stack having a negative end portion and a positive end portion at opposite ends thereof with the edge surfaces of the cells forming a first stack face for admitting a supply of oxidant gas and the edge surfaces forming a second stack face for admitting a supply of fuel gas, porous sealing means at the outer margins of the first stack face and at the outer margins of the second stack face for sealing to the supply of oxidant gas and to the supply of fuel gas, the improvement comprising: a first porous reservoir layer in the negative end portion of said stack having an edge surface thereof exposed to the supply of oxidant gas at the first stack face and being in electrolyte communication with the sealing means for receiving and containing electrolyte migrating towards the negative end of said stack, said first porous layer being separated from all adjacent electrodes and matrices by an electrolyte impermeable, electrically conducted layer; a second porous reservoir layer in the positive end portion of said stack having an edge surface exposed at the second stack face and being in electrolyte communication with the second sealing means for providing reserve electrolyte to fuel cells in the positive end portion of the stack, said second porous layer being separated from all adjacent electrodes and matrices by an electrolyte impermeable electrically conducted layer; and wherein said porous sealing means having a portion of increased cross-section and volume at the negative end portion of said stack and having a portion of its length of lesser volume and cross-section at the midportion of said stack for restricting molten electrolyte migration from the positive to the negative end portion of the stack.
Claim 2
Dependent Claim
341 words
In an electrolytic cell stack including a plurality of electrolytic cells with electrically conductive, electrolyte impermeable separator sheets between adjacent cells in said stack, the electrolytic cells including a porous anode member, a porous cathode member and a porous matrix for molten electrolyte disposed in the stack between major surfaces of the anode and cathode members, said stack having a negative end portion and a positive end portion at opposite ends thereof with the edge surfaces of the cells forming a first stack face for admitting a supply of oxidant gas and the edge surfaces forming a second stack face for admitting a supply of fuel gas, porous sealing means at the outer margins of the first stack face and at the outer margins of the second stack face for sealing to the supply of oxidant gas and to the supply of fuel gas, the improvement comprising: a first porous reservoir layer in the negative end portion of said stack having an edge surface thereof exposed to the supply of oxidant gas at the first stack face and being in electrolyte communication with the sealing means for receiving and containing electrolyte migrating towards the negative end of said stack, said first porous layer being separated from all adjacent electrodes and matrices by an electrolyte impermeable, electrically conducted layer; a second porous reservoir layer in the positive end portion of said stack having an edge surface exposed at the second stack face and being in electrolyte communication with the second sealing means for providing reserve electrolyte to fuel cells in the positive end portion of the stack, said second porous layer being separated from all adjacent electrodes and matrices by an electrolyte impermeable electrically conducted layer; and wherein said porous sealing means having a portion of increased cross-section and volume at the negative end portion of said stack and having a portion of its length of lesser volume and cross-section at the midportion of said stack for restricting molten electrolyte migration from the positive to the negative end portion of the stack.
Claim 3
Dependent Claim
37 words
The electrolytic cell stack of claim 1 wherein said porous sealing means at the midportion of said stack comprises a fiberous ceramic strip containing no more than about 4% by volume molten electrolyte to restrict electrolyte migration.
Claim 4
Dependent Claim
56 words
The electrolytic cell stack of claim 2 wherein said porous sealing means in the midportion of said stack comprises a fiberous ceramic strip having smooth fibers of about 5 to 20 microns diameter, a porosity of more than 90%, a width of about 1 to 2 cm and a thickness of about 0.1 to 0.2 cm.
Claim 5
Dependent Claim
33 words
The electrolytic cell stack of claim 3 wherein said porous sealing means is selected from the group of ceramics consisting of lithium aluminate, lithium zirconate, alumina, ceria, and calcia or yttria stabilized zirconia.
Claim 6
Dependent Claim
65 words
The electrolytic cell stack of claim 1 further comprising an additional porous reservoir layer of electrically conductive material at the negative end portion of said stack exposed to fuel gas at said second vertical face and separated from said first porous layer and adjacent electrodes and electrolyte matrices by at least one electrolyte impermeable, electrically conductive layer at a major surface of the reservoir layer.
Claim 7
Dependent Claim
26 words
The electrolytic cell stack of claim 5 wherein said additional porous layer is of compacted particles of nickel-chromium alloy having a porosity in excess of 50%.
Claim 8
Dependent Claim
29 words
The electrolytic cell stack of claim 1 wherein said first reservoir layer is of greater thickness than that of an individual anode member in the midportion of said stack.
Claim 9
Dependent Claim
140 words
An electrolytic cell stack with a plurality of cells from a positive to a negative end portion, the edge surfaces of said cells forming a first vertical face with sealing means for oxidant gas and a second vertical face with sealing means for fuel gas, said cell stack further comprising the combination of an electronically conductive, electrolyte reservoir in the negative end portion thereof, an electronically conductive, electrolyte reservoir in the positive end portion thereof and sealing means in the midportion thereof, said electrolyte reservoir comprising porous layers of electronically conductive material wettable by electrolyte and separated from adjacent electrodes and matrices by an electrolyte impermeable, electronically conductive layer, said sealing means extending between said reservoirs in the negative and positive stack end portions and being resistant to electrolyte migration between the positive and negative end portions of said stack.
Claim 10
Dependent Claim
140 words
An electrolytic cell stack with a plurality of cells from a positive to a negative end portion, the edge surfaces of said cells forming a first vertical face with sealing means for oxidant gas and a second vertical face with sealing means for fuel gas, said cell stack further comprising the combination of an electronically conductive, electrolyte reservoir in the negative end portion thereof, an electronically conductive, electrolyte reservoir in the positive end portion thereof and sealing means in the midportion thereof, said electrolyte reservoir comprising porous layers of electronically conductive material wettable by electrolyte and separated from adjacent electrodes and matrices by an electrolyte impermeable, electronically conductive layer, said sealing means extending between said reservoirs in the negative and positive stack end portions and being resistant to electrolyte migration between the positive and negative end portions of said stack.
Claim 11
Dependent Claim
38 words
The electrochemical cell stack of claim 8 wherein said electrolyte reservoir at the positive end portion of said stack is filled initially with substantially more electrolyte than the electrolyte reservoir at the negative end portion of said stack.
Claim 12
Dependent Claim
67 words
The electrolytic cell stack of claim 8 wherein said sealing means comprises a fiberous ceramic strip along marginal portions of a stack faces, said strip is of smooth fibers of about 5-20 microns diameter defining a porosity of more than 90%, a width of about 1-2 cm, a thickness of about 0.1 to 0.2 cm, to restrict electrolyte migration along the height of the electrolytic cell stack.
Claim 13
Dependent Claim
34 words
The electrolytic cell stack of claim 8 wherein cells in the positive end portion are filled with electrolyte to a substantially higher level than corresponding cells in the negative end portion of said stack.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-08-02 | 1992-02-01 | 1992-08-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-02 | 1996-02-01 | 1996-08-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-02 | 2000-02-01 | 2000-08-02 | $7700.00 | Window Closed / Lapsed |