Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04007—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids related to heat exchange
  • H01M8/04067—Heat exchange or temperature measuring elements, thermal insulation, e.g. heat pipes, heat pumps, fins
  • H01M8/04074—Heat exchange unit structures specially adapted for fuel cell
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/02—Details
  • H01M8/0297—Arrangements for joining electrodes, reservoir layers, heat exchange units or bipolar separators to each other
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04223—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells
  • H01M8/04225—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells during start-up
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
  • H01M8/043—Processes for controlling fuel cells or fuel cell systems applied during specific periods
  • H01M8/04302—Processes for controlling fuel cells or fuel cell systems applied during specific periods applied during start-up
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/24—Grouping of fuel cells, e.g. stacking of fuel cells
  • H01M8/241—Grouping of fuel cells, e.g. stacking of fuel cells with solid or matrix-supported electrolytes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/24—Grouping of fuel cells, e.g. stacking of fuel cells
  • H01M8/241—Grouping of fuel cells, e.g. stacking of fuel cells with solid or matrix-supported electrolytes
  • H01M8/2425—High-temperature cells with solid electrolytes
  • H01M8/2432—Grouping of unit cells of planar configuration
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/10—Fuel cells with solid electrolytes
  • H01M8/12—Fuel cells with solid electrolytes operating at high temperature, e.g. with stabilised ZrO2 electrolyte
  • H01M2008/1293—Fuel cells with solid oxide electrolytes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M2250/00—Fuel cells for particular applications; Specific features of fuel cell system
  • H01M2250/40—Combination of fuel cells with other energy production systems
  • H01M2250/405—Cogeneration of heat or hot water
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
  • H01M8/04007—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids related to heat exchange
  • H01M8/04014—Heat exchange using gaseous fluids; Heat exchange by combustion of reactants
  • H01M8/04022—Heating by combustion
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M8/00—Fuel cells; Manufacture thereof
  • H01M8/06—Combination of fuel cells with means for production of reactants or for treatment of residues
  • H01M8/0606—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants
  • H01M8/0612—Combination of fuel cells with means for production of reactants or for treatment of residues with means for production of gaseous reactants from carbon-containing material
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02B90/10—Applications of fuel cells in buildings
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/30—Hydrogen technology
  • Y02E60/50—Fuel cells

Definitions

• the present invention relates to solid oxide fuel cells.
• Automobile emissions are said to be a significant contributor to pollution. Automobiles emit hydrocarbons, nitrogen oxides, carbon monoxide and carbon dioxide as a result of the combustion process. In the United State, the Clean Air Act of 1970 and the 1990 Clean Air Act set national goals of clean and healthy air for all and established responsibilities for industry to reduce emissions from vehicles and other pollution sources. Standards set by the 1990 law limit automobile emissions to 0.25 grams per mile (gpm) non-methane hydrocarbons and 0.4 gpm nitrogen oxides. The standards are predicted to be further reduced by half in the year 2004, and similar air quality standards have been or are predicted to be adopted worldwide. It is expected that automobiles will continue to be powered by internal combustion engines for decades to come.
• gpm grams per mile
• SOFC solid oxide fuel cells
• a fuel cell is a device that converts chemical energy into electrical energy. More particularly, a SOFC generates electricity and heat by electrochemically combining across an ion-conducting electrolyte a gaseous fuel, such as hydrogen, carbon monoxide, or a hydrocarbon, and an oxidant, such as air or oxygen.
• a conventional SOFC system typically includes a SOFC, a reformer and a waste energy recovery unit.
• the SOFC is a solid-state device, and includes two electrodes disposed on opposite sides of the ion-conducting electrolyte.
• a SOFC system In operation, a SOFC system generates electricity and heat by directing a flow of oxidant over the oxygen electrode or cathode while the fuel is passed over the fuel electrode or anode, thereby generating electricity, water and heat.
• the fuel (or reformate) provided to the SOFC is produced in the reformer.
• the reformer converts a hydrocarbon or oxygenated fuel into reformats thereof, e.g., hydrogen and carbon monoxide, and byproducts thereof, such as carbon dioxide and water.
• Byproducts from the SOFC, a supply of oxidant, and a supply of reformate are typically directed through the discrete waste energy recovery unit.
• the waste energy recovery unit converts chemical and thermal energy into input thermal energy for the SOFC via one or more heat exchangers.
• the waste energy recovery unit unlike the solid-state SOFC itself, is relatively large and bulky, is constructed of relatively durable and heat transferable materials, and includes many tubes and connections for directing the chemical and thermal energy through the unit.
• SOFC systems were used primarily for stationary power generation in the power generating industry.
• Conventional SOFC systems were not readily adaptable or suitable for use in a motor vehicle.
• Other types of fuel cell systems such as, for example, proton exchange membrane (PEM) systems, have been adapted for use in motor vehicles.
• PEM systems require costly and relatively complex systems for the on-board storage and/or generation of hydrogen and water management systems for on-board fuel reforming and system hydration.
• PEM proton exchange membrane
• the present invention provides an integrated solid oxide fuel cell system.
• the present invention comprises, in one form thereof, a solid oxide fuel cell subassembly having a fuel cell stack fluidly interconnected with a distribution manifold.
• a waste energy recovery subassembly includes a heat exchanger and combustion zone. The waste energy recovery subassembly is fluidly interconnected with the distribution manifold.
• a reformer subassembly is fluidly connected to the waste energy recovery subassembly.
• An advantage of the present invention is that it is suitable for use in a motor vehicle.
• Another advantage of the present invention is that the fuel cell, waste recovery unit and reformer are combined into one unit or system suitable for installation within a vehicle.
• a further advantage of the present invention is that any two or more of the fuel cell system subassemblies can be integrated into one subassembly.
• FIG. 1 is a schematic diagram of one embodiment of an integrated SOFC fuel cell system of the present invention
• FIG. 2 is a schematic diagram of a single electrochemical cell of the SOFC fuel cell stack of Fig. 1 , and illustrates the operation thereof;
• FIG. 3 is a perspective view of the electrochemical cell of Fig. 2;
• FIG. 4 is a perspective view an exemplary integration of the SOFC subassembly and waste energy recovery subassembly of Fig. 1, and illustrates the flow of gasses therethrough;
• FIG. 5 is a perspective view of the integrated SOFC subassembly and waste energy recovery subassembly of Fig. 4.
• SOFC fuel cell system 10 includes reformer subassembly 12, waste energy recovery subassembly 14 and SOFC subassembly 16. Reformer subassembly 12, waste energy recovery subassembly 14 and SOFC subassembly 16 are all disposed within a single system enclosure 20. More particularly, system enclosure 20 includes a first chamber 22, second chamber 24 and third chamber 26. Each of reformer subassembly 12, waste energy recovery subassembly 14 and SOFC subassembly 16 are disposed in first chamber 22. Insulation layer 28 surrounds first chamber 22, and bulkhead 30, such as, for example, a metal or composite plate member, separates second chamber 24 and third chamber 26.
• Reformer subassembly 12 includes main reformer 32 and micro-reformer 34.
• reformer subassembly 12 converts a supply of fuel F and a supply of air A into a flow of reformate, i.e., fuel, to SOFC subassembly 16 via waste energy recovery subassembly 14.
• each of main reformer 32 and micro-reformer 34 receive from fuel supply F a flow of fuel 36a, 36b, respectively, via respective fuel control valves 38a, 38b, such as, for example, fuel injectors, and receive from air supply A respective flows of air 40a, 40b via respective air control valves 42a, 42b.
• Main reformer 32 is fluidly connected to reformate control valve 44, and supplies thereto a flow of fuel/reformate 46.
• Micro-reformer 34 is fluidly connected to main reformer 32 and, as will be more particularly described hereinafter, supplies a flow of pre-reformate 48 to main reformer 32.
• Main and micro-reformers 32, 34 are integrally disposed within reformer subassembly housing 50.
• Main and micro- reformers 32, 34 are configured as exothermic partial oxidation (POx) reformers, and therefore the need for a separate supply of water and/or to re-circulate anode exhaust gases to obtain water vapor are avoided.
• POx exothermic partial oxidation
• Main reformer 32 includes a heating device and/or igniter 32a that heats the catalyst (not shown) contained in main reformer 32 thereby expediting the attainment of a desired operating temperature by main reformer 32.
• Micro-reformer 34 is sized to provide sufficient heat when in a full or substantially full combustion mode and sufficient reformate when in the reforming or normal operation mode to preheat and start-up the downstream device, i.e., main reformer 32, in a predetermined or desired period of time. Operation of main and micro-reformers 32, 34, respectively, is monitored with appropriate sensors (not shown), such as, for example, pressure, temperature, and gas pressure and composition sensors. Main and micro-reformers 32, 34, respectively, are connected in series.
• Waste energy recovery subassembly 14 integrates a catalytic combustion zone 52 and one or more heat exchangers 54. Generally, waste energy recovery subassembly 14 receives a flow of reformate from main reformer 32 via reformate control valve 44. Depending on the mode of operation of SOFC system 10, waste energy recovery subassembly 14 either combusts the reformate, or heats the reformate and a flow of air. The flows of heated reformate and air are supplied to SOFC subassembly 16. Thus, waste energy recovery subassembly 14 converts unused chemical energy (such as unused reformate) and thermal energy (such as the exothermic reaction heat from the SOFC subassembly 16) to input thermal energy for SOFC fuel cell system 10.
• unused chemical energy such as unused reformate
• thermal energy such as the exothermic reaction heat from the SOFC subassembly 16
• waste energy recovery subassembly 14 receives a plurality of working fluids and/or gases.
• Combustion zone 52 and heat exchanger 54 are each fluidly connected to reformate control valve 44.
• reformate control valve 44 Under predefined operating conditions, such as, for example, during a start-up mode of operation of SOFC fuel cell system 10, at least a portion of reformate flow 46 is directed by reformate control valve 44 to combustion zone 52 as start-up or low-grade reformate flow 62.
• at least a portion of reformate flow 46 is directed by reformate control valve 44 to heat exchanger 54 as operating reformate flow 64.
• Combustion zone 52 is further fluidly connected to and receives from SOFC subassembly 16 a flow of cathode exhaust 74 and anode exhaust 76. Under certain operating conditions, such as, for example, shut down, a flow of purge air from first chamber 22 is fluidly coupled to combustion zone 52 via inlet 78.
• Waste energy recovery subassembly 14 also exhausts and/or transfers a plurality of fluids and/or gases during the operation of SOFC fuel system 10. More particularly, the flows of operating reformate 64 and cathode air 66 are passed through heat exchanger 54 and to SOFC subassembly 16, as will be more particularly described hereinafter. Further, waste energy recovery subassembly 14 emits exhaust flow 80, e.g., a flow of reaction byproducts such as water, carbon dioxide and air, to the exterior of system enclosure 20.
• exhaust flow 80 e.g., a flow of reaction byproducts such as water, carbon dioxide and air
• Waste energy recovery subassembly 14 is embodied as a series of connected generally flat plate structures (not shown) having one or more openings or manifold passages along or bordering the edge of the plate for guiding the flow of oxidant, reformate or exhaust gases.
• the plates also include features (not shown), such as, for example, etchings, chevrons or channels, that are disposed, for example, in or near the center portion of the plates for guiding the movement of the oxidant, reformate or exhaust.
• the oxidant, reformate and exhaust enter the waste energy recovery subassembly 14 via respective inputs, as described above, and are guided through respective features/channels and across the plates to corresponding outlet passages.
• the flows of oxidant, reformate and/or exhaust are separated from each other by the features/channels to prevent mixing of the gases.
• SOFC subassembly 16 includes SOFC fuel cell stack 90 and distribution manifold 92. Generally, SOFC subassembly 16 distributes the flow of operating reformate 64 and cathode air 66, and converts those flows to electricity.
• SOFC fuel cell stack 90 is a multi-layer ceramic / metal composite fuel cell having the capacity to produce a predetermined amount of electricity, such as, for example, a level of current sufficient to drive the electrical load presented by the various electrical devices found on a typical automobile.
• SOFC fuel cell stack 90 produces electricity at an operating temperature of from approximately 600°C to approximately 1000°C, and
• SOFC fuel cell stack 90 includes one or more electrically and fluidly interconnected multi-cell modules (not shown), and includes an electrode 94 that extends from system enclosure 20 for connecting SOFC fuel cell stack 90 to an electrical load, such as, for example, a power bus (not shown) of a motor vehicle.
• a schematic representation of a single cell 100 of mutli- layer, multi-cell fuel cell stack 90 is shown to illustrate the operation of fuel cell stack 90.
• Anode 102 and cathode 104 are disposed on opposite sides of and spaced apart by oxygen ion conducting electrolyte 106.
• Reformate flow 64 is directed over anode 102, and cathode air flow 66 is passed over cathode 104 of cell 100. Cathode flow 66 is reduced in the presence of electrolyte 106. Oxygen ions (O "2 ) are thereby generated and move through electrolyte 106 to anode 102, as summarized by the following reaction: O 2 + 4e " -> 2(O "2 ).
• reformate flow 64 is oxidized in the presence of electrolyte 106 and the migrating oxygen ions.
• the reaction of reformate flow 64 with the oxygen ions produces electrons (e " ), which flow to external circuit 110 and back to cathode 104.
• Unreacted fuel byproducts such as, for example, carbon monoxide, water, and carbon dioxide, exit cell 100 in anode exhaust flow 76, which is in turn directed by distribution manifold 92 to combustion zone 52 of waste energy recovery subassembly 14.
• cell 100 includes anode plate 102 which is spaced apart and separated from cathode plate 104 by electrolyte 106.
• Collector 112 is disposed adjacent the side (not referenced) of anode 102 that is opposite electrolyte 106, and collector 114 is disposed adjacent the side (not referenced) of cathode 104 that is opposite electrolyte 106.
• An anode plate 116 of a second cell (not shown) is disposed below, i.e., on the opposite side of, collector 114, thereby illustrating the placement of and ability to stack several cells in electrical communication with cell 100.
• the anode 102 and cathode 104 which with electrolyte 106 form phase boundaries between gas/electrolyte/catalyst commonly known as triple points, are disposed adjacent to and/or integral with electrolyte 106.
• Anode 102 and cathode 104 are generally formed of porous material capable of functioning as an electrical conductor and capable of facilitating the reactions described herein. More particularly, the porosity of the material that comprises anode 102 and cathode 104 should be sufficient to enable dual directional flow of gases, i.e., the admission of fuel or oxidant gases and the exit of byproducts. Even more particularly, the porosity of the material that comprises anode 102 and cathode 104 should be up to approximately 40 percent and ideally from approximately 20 to approximately 40 percent.
• Anode 102 and cathode 104 are constructed of material that include elements such as zirconium, yttrium, nickel, manganese, strontium, lanthanum and oxides, alloys and combinations including at least one of the foregoing elements.
• Anode 102 is preferably formed upon a ceramic skeleton, such as, for example, a yttria-stabilized zirconia, for thermal compatibility.
• Both anode 102 and cathode 104 are formed on electrolyte 106 by a variety of techniques, such as, for example, sputtering, chemical vapor deposition, screen printing, spraying, dipping, stenciling and painting.
• the anode 102 and cathode 104 electrodes are typically up to approximately 1 ,000 microns in thickness, with a thickness of from approximately 10 to approximately 50 microns typically being preferred.
• cell 100 can be configured as an anode supported cell by forming electrolyte 106 and cathode 104 on anode 102 using any of the above deposition/application techniques.
• cathode 104 or an inert layer (not shown) can be substituted as the support for cell 100.
• Electrolyte 106 is an ion conductor capable of transporting oxygen ions from the cathode 104 to the anode 102, and which is compatible with the environment in which SOFC fuel cell system 10 is to be used, such as, for example, in temperatures of up to approximately 1000°C.
• suitable materials for electrolyte 106 include ceramics, such as, for example, perovskite and/or fluorite, metals, such as, for example, alloys, oxides, and/or gallates.
• suitable electrolyte materials include, for example, zirconium, yttrium, calcium, cerium, magnesium, aluminum, rare earth metals, oxides, gallates, aluminates, and combinations and/or composites of at least one of the foregoing materials.
• a rare earth oxide such as, for example, yttria, gadolinia, neodymia, and the like doped with aliovalient oxides, such as, for example, magnesia, calcia, strontia, and other +2 valence metal oxides, are used for the material of electrolyte 106.
• a yttria-stabilized zirconia material is used for electrolyte 106.
• Collectors 112, 114 include passages (not referenced) for guiding the flow of fuel and oxidant, respectively.
• Collectors 112 and 114 are generally formed of electrically conductive material that is capable of withstanding the temperatures and pressures under which SOFC fuel cell system 10 is operated.
• collectors 112 and 114 are constructed of materials, such as, for example, silver, copper, ferrous materials, strontium, lanthanum, chromium, chrome, gold, platinum, palladium, nickel, titanium, conducting ceramics, or composites and combinations of at least one of the foregoing, that are capable of withstanding the operating conditions of a motor vehicle, i.e., ambient temperatures from approximately - 40°C to operating temperatures of approximately 1000°C.
• Each individual cell 100 generates approximately from 0.5 volts to approximately 1.2 volts direct current.
• the desired output voltage of SOFC fuel cell system 10 is obtained by connecting in series a plurality of cells 100 together, as described herein.
• Gas distribution manifold 92 fluidly interconnects SOFC fuel cell stack 90 with waste energy recovery subassembly 14. More particularly, gas distribution manifold 92 receives heated reformate flow 64 and heated cathode air flow 66 from waste energy recovery subassembly 14 via inlet/outlet manifold 120 (Figs. 4 and 5), and distributes those flows to the SOFC fuel cell stack 90. Gas distribution manifold 92 further directs anode and cathode exhaust flows 74 and 76, respectively, from SOFC fuel cell stack 90 to combustion zone 52 of waste energy recovery subassembly 14. After combustion thereof, any remaining byproducts are exhausted via exhaust flow 80. It should be particularly noted that, as best shown in Figs.
• gas distribution manifold 92 integrates into a unitary subassembly (not referenced) the waste energy recovery subassembly 14 and SOFC subassembly 16. More particularly, as shown in Fig. 5, fuel cell stack 90, distribution manifold 92, waste energy recovery subassembly 14 and inlet/outlet manifold 120, are integrated into a single unitary subassembly (not referenced) by fasteners 121 , such as, for example, bolts.
• anode exhaust 76 and cathode exhaust 74 are routed back to combustion zone 52 of waste energy recovery subassembly 14, where they are mixed with air flow 70 and burned.
• the burning of the anode and cathode exhausts 76, 74, respectively, in combustion zone 52 heats heat exchanger 54 of waste energy recovery subassembly 14.
• cooling air control valve 122 is actuated and connects a flow of cooling air 124 to cathode air flow 66, thereby blending cooler air with cathode air flow 66 and controlling the temperature of SOFC subassembly 16.
• the thermal management (not referenced) of SOFC fuel cell system 10 should be particularly noted.
• the thermal management system of SOFC fuel cell system includes first, second and third chambers 22, 24 and 26, respectively, and is designed to insulate the internal hardware of SOFC fuel cell system 10 and maintain the exterior temperature of system enclosure 20 at approximately 90°C or less.
• System enclosure 20 supports the components of SOFC fuel cell system 10, and can optionally be actively temperature controlled in a known manner.
• System enclosure 20 surrounds and defines at least in part second and third chambers 24 and 26, respectively.
• First chamber 22 is housed internally to second chamber 24, and contains reformer subassembly 12, waste energy recovery subassembly 14, SOFC subassembly 16 and other high-temperature components (not shown), such as, for example, sensors and controllers.
• reformer subassembly 12, waste energy recovery subassembly 14 and SOFC subassembly 16 are integrated within first chamber 22.
• the thermal management system includes two means that actively control the temperature of system enclosure 20.
• cooling air lid passage 128 is defined by lid 126 of system enclosure 20.
• Lid 126 incorporates a thin heat exchanger (not shown) across the entire surface thereof.
• the surface of lid 126 provides a contact point to vehicle 130 and therefore operates at a lower temperature than the other surfaces of system enclosure 20.
• Main blower 132 is disposed within system enclosure 20 and together with air control valve 134 selectively draws cooling air A through cooling air lid passage 128, thereby cooling the surface of system enclosure 20 that is in contact with vehicle 130 and pressurizing third chamber 26 to a pressure P1.
• main blower 132 and valve 134 are controlled and adjusted dependent at least in part upon the temperature of the incoming cooling air, and preferably cools the surface of system enclosure 20 to approximately 90°C or less, and more preferably to approximately 45°C or less.
• Air control valve 136 controls the flow of air into second chamber 24 and thereby regulates pressure P2 and ensures the appropriate degree of cooling is attained.
• Insulation layer or wall 28 is disposed between first chamber 22 and second chamber 24, and also forms part of the thermal management system of SOFC fuel cell system 10.
• a flow of air 137 from second chamber 24 through insulation layer 28 and into first chamber 22 cools first chamber 22.
• the flow of air 137 pressurizes first chamber 22 to a pressure P3, which is maintained at a level that is a predetermined amount less than P2. Once the flow of air has reached first chamber 22, the air is referred to as purge air.
• the purge air is drawn (or pushed by the pressure P2 and P3 differentials) into inlet 78 of waste energy recovery system 14, and is exhausted from SOFC fuel cell system 10.
• the above described thermal management system controls the exterior temperature of first chamber 22 to a temperature of approximately 200°C or less, and
• a process air system (not referenced) provides cooling air to the thermal management system and to the other components of SOFC fuel cell system 10 that utilize/require air.
• the process air system draws air from air supply A, such as, for example, an external air supply.
• Air supply A is processed through air filter 142 and directed through cooling air passage 128 in lid 122 and to main blower 132, as described above.
• Main blower 132 is disposed within third chamber 26, and delivers air through process air control valve 134 to third chamber 26 and, thus, to the thermal management system of SOFC fuel cell system 10.
• Main blower 132 pressurizes the chambers 22, 24 and 26, thereby providing for the cooling and purging thereof.
• main blower 132 pressurizes the chambers appropriately and as described above.
• Fuel supply F enters and thus pressurizes the fuel system and operation of micro-reformer 34 is commenced, such as, for example, by energizing an electrically heated element (not shown) in the fuel vaporization zone thereof.
• Micro-reformer 34 receives fuel flow 36a from fuel injector 38a and receives air flow 40a from air control valve 42a, and produces pre-reformate 48.
• Pre-reformate flow 48 is routed through and heats main reformer 34.
• pre-reformate flow 48 is also routed through and heats waste energy recovery subassembly 14 and SOFC subassembly 16.
• Appropriate sensors monitor the properties of reformate flows 62 and 64.
• a predetermined minimum start-up temperature such as, for example, approximately 600°C
• fuel valve 38b and air control valve 42b are actuated to thereby supply fuel flow 36b and air flow 40b to main reformer 32.
• Main reformer 32 thus begins producing operating reformate flow 46.
• At least a portion of reformate flow 46 is directed by reformate control valve 44 through combustion zone 52 as refromate flow 62 during the start up operating mode of SOFC fuel cell system 10.
• the combustion of reformats within combustion zone 52 heats heat exchangers 54.
• fuel cell stack 90 reaches a predetermined lower or minimum operational temperature limit, such as, for example, approximately 650°C or greater and preferably
• SOFC subassembly 16 transitions from the start-up mode of operation to the normal mode of operation. At least a portion of reformate flow 46 is re-directed by reformate control valve 44 to flow as reformate flow 64 through heat exchanger 54 and to SOFC subassembly 16, rather than through combustion zone 52 as reformate flow 62.
• the output, i.e., cathode and anode exhaust flows 74, 76, respectively, are routed through combustion zone 52 where they are mixed with air flow 70 and catalyzed.
• Shutdown from normal operating mode includes cooling SOFC system 10 to near ambient conditions, the electrical load placed upon SOFC system 10 is removed and anode supply 64 is reduced to a predetermined minimum flow necessary to avoid/prevent anode oxidation.
• Cathode air supply 66 and pressures P1, P2 and P3 are maintained at least in part to promote air cooling of SOFC fuel system 10 and exhaust purge air therefrom via inlet 78.
• Reformer subassembly 12 is shut down when the air cooling has lowered the temperature of SOFC subassembly has decreased to a point below that at which anode oxidation occurs, i.e., approximately 200°C.
• each of main and micro-reformers 32, 34 are configured as partial oxidation reduction reformers.
• each of main and micro- reformers 32, 34 respectively, receive from fuel supply F a flow of fuel 36a, 36b, respectively, via respective fuel control valves 38a, 38b, such as, for example, fuel injectors, and receive from air supply A respective flows of air 40a, 40b via respective air control valves 42a, 42b.
• the present invention can be alternately configured, such as, for example, with one or more micro and/or main steam reformer(s), thereby requiring a source of steam or water be fluidly connected to the reformer(s) rather than a supply of air.
• the integrated SOFC fuel system of the present invention is configured to include the fuel cell stack, fuel reformer, and waste energy recovery subassembly (including one or more heat exchangers and a combustor) into a single unit or housing.
• the present invention can be alternately configured as a system that integrates any combination of the above, such as, for example, a combustor, reformer and heat exchanger, or a fuel cell, reformer and one or more heat exchangers into a single unit or housing.
• the integrated SOFC fuel system of the present invention integrates into a single chamber, within a single system enclosure, a reformer, waste energy recovery subassembly, and SOFC subassembly.
• a reformer waste energy recovery subassembly
• SOFC subassembly SOFC subassembly.
• the present invention can be alternately configured with chambers and an enclosure having a different geometric configuration, such as, for example, generally concentric spherical chambers generally concentrically contained within a generally spherical system enclosure.
• the micro-reformer is configured as an exothermic POx reduction reformer.
• the micro-refromer can be alternately configured, such as, for example, as a reformer, a catalytic or gas phase combustor. While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the present invention using the general principles disclosed herein. Further, this application is intended to cover such departures from the present disclosure as come within the known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

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• 2002
  • 2002-04-19 WO PCT/US2002/012315 patent/WO2002087052A2/en not_active Application Discontinuation
  • 2002-04-19 AU AU2002258864A patent/AU2002258864A1/en not_active Abandoned
  • 2002-04-19 EP EP02728838A patent/EP1382079A4/de not_active Withdrawn

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