Fuel cell and fuel cell system for an aircraft

Abstract

A fuel cell to provide a higher power density. The fuel cell can be produced by 3D printing in ceramic and has an improved power density by virtue of its spiral shape. In order to better extract the energy generated by the fuel cell, an interconnector sheet can be fastened positively to fastening knobs of the fuel cell by holding eyes. In addition, the interconnector sheet can be fixed by glass solder.

Claims

1. A fuel cell for a fuel cell system, the fuel cell comprising: a first fuel cell region that forms a first gas channel for a flow of a fuel through the first gas channel; a second fuel cell region that forms a second gas channel for a flow of an oxidizer through the second gas channel; a first distribution tube comprising: a gas supply region for providing the fuel to the first gas channel of the first fuel cell region; and a gas discharge region for discharging, from the first gas channel of the first fuel cell region, reaction product and/or any of the fuel that is unconsumed; and a second distribution tube comprising: a gas supply region for providing the oxidizer to the second gas channel of the second fuel cell region; and a gas discharge region for discharging, from the second gas channel of the second fuel cell region, reaction product and/or any of the oxidizer that is unconsumed; and wherein the first and second gas channels that are formed, respectively, by the first and second fuel cell regions both extend in a circumferential direction around a construction axis; wherein, when viewed along the construction axis, the first and second distribution tubes are both at least partially surrounded by both of the first and second gas channels of the first and second fuel cell regions, respectively; wherein the first gas channel comprises a gas inlet region and a gas outlet region, the gas inlet region and the gas outlet region of the first gas channel being arranged such that, when a further first fuel cell region is arranged or formed offset from the first fuel cell region along the construction axis, the gas outlet region of the first gas channel is aligned with and/or fluidically connected to a gas inlet region of a further first gas channel of the further first fuel cell region, the further first gas channel being configured for receiving the flow of the fuel from the first gas channel; wherein the second gas channel comprises a gas inlet region and a gas outlet region, the gas inlet region and the gas outlet region of the second gas channel being arranged such that, when a further second fuel cell region is arranged or formed offset from the second fuel cell region along the construction axis, the gas outlet region of the second gas channel is aligned with and/or fluidically connected to a gas inlet region of a further second gas channel of the further second fuel cell region, the further second gas channel being configured for receiving the flow of the oxidizer from the second gas channel; wherein the fuel cell is divided into subsections that each contain a respective portion of each of the first and second gas channels of the first and second fuel cell regions, the first and second distribution tubes being connected for providing, within each of the subsections and in parallel, the respective portion of each of the first and second gas channels contained therein with the fuel and the oxidizer, respectively.

2. The fuel cell of claim 1, wherein the first gas channel and the second gas channel extend in a circumferential direction about the construction axis in a form of a double helix.

3. The fuel cell of claim 1, wherein the first and second fuel cell regions comprise a plurality of the first fuel cell regions and a plurality of the second fuel cell regions, the plurality of the first fuel cell regions and the plurality of the second fuel cell regions being arranged along the construction axis such that the first gas channels and the second gas channels are in each case fluidically connected.

4. The fuel cell of claim 1, wherein an ion-conductive separating layer is on one of the first and second gas channels or between adjacent gas channels of the first and second gas channels to connect the adjacent gas channels to one another in an ion-conducting manner.

5. The fuel cell of claim 1, wherein the first and second gas channels, when viewed in a direction of extent thereof, enclose an angle between 30° and 60°, with a plane orthogonal to the construction axis.

6. The fuel cell of claim 1, wherein the first and second gas channels form a double helix.

7. The fuel cell of claim 1, wherein each of the first and second gas channels has a gas channel curvature region and an adjoining gas channel plane region, wherein the gas inlet regions and/or the gas outlet regions are arranged on the gas channel plane region in a middle of the gas channel plane region.

8. The fuel cell of claim 7, wherein each distribution tube is arranged within a region surrounded by the gas channel curvature region and the gas channel plane region of the first and second gas channels.

9. The fuel cell of claim 1, wherein each of the first and second gas channels contains a conductive electrode coating for extracting generated electrical energy from the fuel cell.

10. The fuel cell of claim 9, comprising interconnector sheets, wherein each interconnector sheet is arranged on one of the first and second fuel cell regions and is embedded in a respective electrode coating for extracting the generated electrical energy from a corresponding one of the first and second fuel cell regions.

11. The fuel cell of claim 1, where the fuel cell is a solid oxide fuel cell of an aircraft.

12. A fuel cell system for an aircraft, comprising: a plurality of fuel cells of claim 1; wherein the plurality of fuel cells are arranged in one plane and/or stacked at a distance from each other along the construction axis.

13. An aircraft comprising a fuel cell of claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Example embodiments of the disclosure herein are explained in greater detail below with reference to the attached schematic drawings. In the drawings:

(2) FIG. 1 shows an example of a spiral fuel cell;

(3) FIG. 2 shows an example of a flat fuel cell region;

(4) FIG. 3 shows a plurality of fuel cell regions;

(5) FIG. 4 shows an example of a fuel cell from the fuel cell regions of FIG. 2;

(6) FIG. 5 shows a section through the fuel cell of FIG. 4;

(7) FIG. 6 shows another example of a fuel cell;

(8) FIG. 7 shows a schematic view of the gas supply to the fuel cell of FIG. 6;

(9) FIG. 8 through FIG. 12 show an example embodiment of a fuel cell with interconnector sheets;

(10) FIG. 13 shows an example of an interconnector sheet;

(11) FIG. 14 shows the interconnector sheet of FIG. 13 in the installed state;

(12) FIG. 15 through FIG. 17 show example embodiments of a fastening of the interconnector sheet;

(13) FIG. 18 and FIG. 19 show an example relating to the production of the interconnector sheet of FIG. 13;

(14) FIG. 20 and FIG. 21 show an example embodiment of a fuel cell system;

(15) FIG. 22 shows an example embodiment of a fuel cell;

(16) FIG. 23 shows a schematic illustration of the inflow and outflow of gas in the fuel cell of FIG. 22;

(17) FIG. 24 shows a detail view of wiring of the fuel cell of FIG. 22;

(18) FIG. 25 shows an example embodiment of an interconnector sheet; and

(19) FIG. 26 shows an example of a wiring operation of the fuel cell.

DETAILED DESCRIPTION

(20) Reference is made first of all to FIG. 1, which shows an example of a fuel cell 10. The fuel cell 10 has a first fuel cell region 12 and a second fuel cell region 14. Each fuel cell region 12, 14 contains a gas channel 16.

(21) The first fuel cell region 12 comprises a first gas channel 18, e.g. for an oxidizer, and the second fuel cell region 14 comprises a second gas channel 20, e.g. for fuel.

(22) The first gas channel 18 and the second gas channel 20 extend spirally in a circumferential direction about a construction axis 22. Here, the construction axis 22 extends in the center of the spiral.

(23) The first gas channel 18 and the second gas channel 20 are connected to one another along their direction of extent by an ion-conductive separating layer 24. Furthermore, an insulation layer 26 is arranged in order to prevent a cell short circuit.

(24) Each gas channel 16 may include an electrode coating 28 to extract the generated electrical energy from the fuel cell 10.

(25) Reference is made to FIGS. 2 through 4, which show an example of a fuel cell 30. The fuel cell 30 comprises a plurality of fuel cell regions 32. In this case, a first fuel cell region 34 and a second fuel cell region 36 can be designed as one piece.

(26) Each fuel cell region 32 comprises a first gas channel 38 and a second gas channel 40, respectively. The fuel cell region 32 is designed in such a way that the gas channels 38, 40 extend in the circumferential direction around a construction axis 42. In FIGS. 2 and 3, the construction axis 42 is perpendicular to the plane of the drawing.

(27) Each of the gas channels 38, 40 has a gas channel curvature region 44 and an adjoining gas channel plane region 46. The gas channel curvature region 44 is preferably curved by 180°. The gas channel plane region 46 is straight and without any curvature, resulting in an elongate oval shape of the fuel cell region 32.

(28) The first gas channel 38 and the second gas channel 40 each have a gas inlet region 48. The gas inlet region 48 can be seen in the plan view of FIGS. 2 and 3 and is not shown specifically in FIG. 4. In FIG. 4, the gas inlet region 48 is oriented upward. The gas inlet region 48 is arranged in the middle of the gas channel plane region 46, for example. The gas inlet region 48 is preferably arranged in such a way that, for example, when a further fuel cell region 32 is arranged along the construction axis 42, the gas inlet region 48 is fluidically connected to the respective gas channel 38, 40 of the further fuel cell region 32.

(29) The first gas channel 38 and the second gas channel 40 each have a gas outlet region 50. In the plan view of FIGS. 2 and 3, the gas outlet region 50 is below the plane of the drawing and can therefore not be seen. In FIG. 4, the gas outlet region 50 is oriented downward. The gas outlet region 50 is arranged in the middle of the gas channel plane region 46, for example. The gas outlet region 50 is preferably arranged in such a way that, for example, when a further fuel cell region 32 is arranged along the construction axis 42, the gas inlet region 48 is fluidically connected to the gas outlet region 50 of the respective gas channel 38, 40 of the further fuel cell region 32.

(30) Each gas channel 38, 40 may include an electrode coating 52 to extract the generated electrical energy from the fuel cell 30.

(31) Overall, a continuous first gas channel 38 and second gas channel 40 can be formed in this way. Thus, the effective area is significantly increased and the volumetric power density can be increased.

(32) As illustrated in FIG. 5, the gas channels 38, 40 may be formed at an angle α relative to the horizontal direction. With this embodiment, production by 3D printing can be simplified because fewer or no support structures are required.

(33) Reference is made to FIGS. 6 and 7, which show an example of a fuel cell 54 in different variants. The fuel cell 54 comprises a plurality of fuel cell regions 32, a first distribution tube 56, and a second distribution tube 58. The first distribution tube 56 can be provided for the fuel, while the second distribution tube 58 can be provided for the oxidizer.

(34) The distribution tubes 56, 58 are arranged in a region which is surrounded or, as seen in plan view, enclosed by the gas channels 38, 40. In the present case, the distribution tubes 56, 58 extend parallel to the construction axis 42.

(35) Each distribution tube 56, 58 has a gas supply region 60, which can be designed to be connectable to a gas reservoir. In the case of the oxidizer, the gas supply region 60 can serve for air supply without a gas reservoir.

(36) In addition, each distribution tube 56, 58 has a gas discharge region 62, from which unused residual gas and reaction product can emerge.

(37) In the variant shown in FIG. 6, the first distribution tube 56 serves to distribute the fuel and the second distribution tube 58 serves to distribute the oxidizer. In this variant, the first distribution tube 56 forms a continuous fluid path with the first gas channel 38 and the second distribution tube 58 forms a continuous fluid path with the second gas channel 40.

(38) In the variant shown in FIG. 7, the fuel cell 54 is divided into three subsections 64, for example. Each subsection 64 is supplied with fuel and oxidizer through the distribution tubes 56, 58 independently of the other subsections 64.

(39) Reference is made to FIG. 8 through FIG. 14, which show an example of a fuel cell 66. Fuel cell 66 is similar in design to fuel cell 54 and additionally comprises a plurality of interconnector sheets 68. Each interconnector sheet 68 is arranged on a fuel cell region 70 of the fuel cell 64. The generated electrical energy can be extracted by the interconnector sheets 68.

(40) The interconnector sheet 68 comprises a plurality of contact tongues 71. Each contact tongue 71 projects either into the first gas channel 38 or into the second gas channel 40. The contact tongues 71 are fastened to the wall of the respective gas channel 38, 40. The electrode coating 52 is preferably arranged in such a way that the contact tongues 71 are embedded in the electrode coating 52.

(41) Each interconnector sheet 68 further comprises an electrical connection region 72. The connection regions 72 are designed in such a way that they can be electrically connected along a connection axis 74 by a threaded rod. Each connection region 72 may have a connection opening 76 for the threaded rod. In other words, the connection openings 76 of the connection regions 72 are aligned.

(42) Each interconnector sheet 68 has a band-like region 78. The band-like region 78 is matched to the contour of the fuel cell region 70 in such a way that the band-like region 78 conforms to the fuel cell region 32. The band-like region 78 is preferably of C-shaped design. A holding eye 80 is arranged at each of the opposite ends of the band-like region 78.

(43) The fuel cell region 70 comprises a holding device 81 which fits the holding eyes 80 in order to hold the interconnector sheet 68. The holding device 81 has fastening knobs 82 in order to produce a positive connection to the holding eyes 80.

(44) Each fastening knob 82 is arranged on an outer circumferential surface of the fuel cell region 70. The fastening knob 72 is preferably of substantially hemispherical design. The interconnector sheets 68 can be secured on the fuel cell region 70 by glass solder. In this case, the glass solder can seal any remaining openings.

(45) The fuel cell region 70 further comprises an aperture 84 for each contact tongue 71.

(46) As illustrated in FIGS. 15 through 17, the holding eyes 80 and the fastening knobs 82 may have different shapes. FIG. 15, on the left, illustrates a hemispherical fastening knob 82, with which a circular holding eye 80 is associated (FIG. 15, in the center). FIG. 15, on the right, shows the positive connection which prevents the interconnector sheet 68 from sliding off the fuel cell region 70.

(47) A further variant is illustrated on the left in FIG. 16, which shows a quarter-spherical fastening knob 82. This is associated with a D-shaped holding eye 80 (FIG. 16, in the center). By virtue of the steep flank of the fastening knob 82, slipping off can be prevented even better (FIG. 16, on the right). It is also possible to keep the interconnector sheet 68 slightly under mechanical stress and thus to enable even better application to the fuel cell region 70.

(48) With the variant shown in FIG. 17, the positive fit can be further improved. As in FIG. 16, a D-shaped holding eye 80 is required. However, the fastening knob 82 is at an acute angle to the horizontal.

(49) The production of an interconnector sheet 68 is explained in more detail below with reference to FIG. 18 and FIG. 19. An interconnector sheet blank 86 is cut out of a flat sheet metal material initially provided.

(50) The interconnector sheet blank 86 already has a plurality of rectangular contact tongues 71, a connection region 72, a band-like region 78 as well as holding eyes 80.

(51) The interconnector sheet blank 86 is formed into the finished interconnector sheet 68 by bending. In this case, the band-like region 78 is bent in such a way that the interconnector sheet 68 can conform to the fuel cell region 70. The holding eyes 80 are bent to positions corresponding to the fastening knobs 82. The contact tongues 71 receive the angle α, which corresponds to the slope of the gas channels 38, 40 with respect to the horizontal direction. Finally, the connection region 72 can also be bent into the horizontal.

(52) Reference is made below to FIG. 20 and FIG. 21, which each show an example of a fuel cell system 88. The fuel cell system 88 comprises a plurality of fuel cells 90, which is illustrated in more detail in FIG. 22 to FIG. 24.

(53) The fuel cells 90 have a roughly hexagonal shape in plan view. The fuel cells 90 are arranged in a plane at a distance from each other, as shown in detail, for example, in FIG. 20. The fuel cells 90 may also be staggered along their construction axis 22, as shown in detail in FIG. 21. A combination of the arrangements in which the fuel cells 90 are arranged in a plurality of planes one above the other is also conceivable.

(54) An example of the fuel cell 90 will be explained in detail below with reference to FIG. 22 through FIG. 24.

(55) The fuel cell 90 has a first fuel cell region 92 and a second fuel cell region 94. Each fuel cell region 92, 94 contains a gas channel. In the present case, the first fuel cell region 92 and the second fuel cell region 94 are formed integrally as a single one-piece element.

(56) The first fuel cell region 92 comprises a first gas channel, e.g. for an oxidizer, and the second fuel cell region 94 comprises a second gas channel, e.g. for fuel.

(57) The first gas channel and the second gas channel extend in the form of a double helix in a circumferential direction about the construction axis 22. The construction axis 22 extends in the center of the fuel cell 90.

(58) The first gas channel and the second gas channel are preferably connected to one another along their direction of extent by an ion-conductive separating layer. Furthermore, an insulation layer can be arranged in order to prevent a cell short circuit.

(59) Each gas channel may include an electrode coating 96 to extract the electrical energy generated therein from the fuel cell 90.

(60) Each of the gas channels has a plurality of gas channel curvature regions 98 and adjoining gas channel plane regions 100. Each gas channel curvature region 98 is preferably curved by 120°. Each gas channel plane region 100 is straight and without any curvature.

(61) Overall, a substantially hexagonal shape of the fuel cell regions 92, 94 is obtained in plan view.

(62) The fuel cell 90 comprises a first distribution tube 102 and a second distribution tube 104. The first distribution tube 102 can be provided for the fuel, while the second distribution tube 104 can be provided for the oxidizer.

(63) The distribution tubes 102, 104 are arranged in a region which is surrounded or, as seen in plan view, enclosed by the gas channels. The distribution tubes 102, 104 are preferably arranged in the center of the fuel cell 90, as seen in plan view. In the present case, the distribution tubes 102, 104 extend parallel to the construction axis 22.

(64) Each distribution tube 102, 104 has a gas supply region 106, which can be designed to be connectable to a gas reservoir. In the case of the oxidizer, the gas supply region 106 can serve for air supply without a gas reservoir.

(65) In addition, each distribution tube 102, 104 has a gas discharge region 108, from which unused residual gas and reaction product can emerge.

(66) For example, first distribution tube 102 may be provided for distribution of the fuel and form a continuous fluid path with the first gas channel. In other words, the gas supply region 106 of the first distribution tube 102 is fluidically connected to the gas discharge region 108 of the first distribution tube 102 via the first gas channel.

(67) The second distribution tube 58 can be used to distribute the oxidizer and form a continuous fluid path with the second gas channel. In other words, the gas supply region 106 of the second distribution tube 104 is fluidically connected to the gas discharge region 108 of the second distribution tube 104 via the second gas channel.

(68) The fuel cell 90 may be internally divided into a plurality of subsections which may be supplied with fuel and oxidizer through the distribution tubes 102, 104 independently of the other subsections.

(69) The fuel cell 90 additionally comprises a plurality of apertures 110 for interconnector sheets. The apertures 110 are preferably arranged in the gas channel plane regions 100. The apertures 110 may be arranged at the respective ends of the gas channel plane region 100, adjacent to the gas channel curvature regions 98.

(70) The fuel cell 90 comprises a holding device 112 for interconnector sheets. The holding device 112 is arranged in the vicinity of or in the apertures 110.

(71) The fuel cell 90 also comprises a winding structure 114 for a conductive element 116, e.g. a wire. The winding structure 114 is on the outer circumferential surface of the fuel cell 90. The winding structure 114 is of spiral design. The winding structure 114 preferably comprises a groove 118 which extends in such a way that interconnector sheets of the same polarity can be electrically connected to one another by winding the conductive element 116 around the winding structure 114.

(72) Furthermore, the conductive element 116 may have insulation that prevents the conductive element 116 from causing a short circuit. The conductive element 116 may also contain a plurality of wires, each of which is associated with one interconnector polarity and only comes into contact with the latter.

(73) The fuel cell 90 furthermore comprises a plurality of interconnector sheets 120.

(74) Each interconnector sheet 120 comprises a single contact tongue 122. The contact tongue 120 projects into the first gas channel or into the second gas channel. The contact tongues 120 are each fastened to the wall of the respective gas channel. The electrode coating 96 is preferably arranged in such a way that the contact tongues 120 are embedded in the electrode coating 96.

(75) Each interconnector sheet 120 further comprises an electrical connection region 124, which adjoins the contact tongue 120. The connection region 124 is designed in such a way that it faces radially outward in the installed state of the interconnector sheet 120 and can be engaged by a conductive element 116.

(76) Each interconnector sheet 120 has a clamping region 126. The clamping region 126 extends substantially parallel to and at a distance from the contact tongue 120. The interconnector sheet 120 can therefore be inserted into the aperture 110 and held on the fuel cell 90.

(77) In the following, reference is made to FIG. 26. As illustrated, the fuel cell 90 may be electrically connected by first inserting the interconnector sheets 120 into the apertures 110. The conductive element 116 can then be wound around the outer circumferential surface of the fuel cell 90 using the winding structure 114. In this case, the conductive element 116 comes into contact with the interconnector sheets 120, to be more precise the electrical connection region 124. Any remaining openings can be sealed by glass solder. At the same time, the glass solder can be used for fastening the interconnector sheets 120.

(78) In order to provide a higher power density, a fuel cell (66) is proposed. The fuel cell (66) can be produced by 3D printing in ceramic and has an improved power density by virtue of its spiral shape. In order to better extract the energy generated by the fuel cell (66), an interconnector sheet (68) is proposed which can be fastened positively to fastening knobs (82) of the fuel cell (66) by holding eyes (80). In addition, the interconnector sheet (68) can be fixed by glass solder.

(79) While at least one example embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the example embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a”, “an” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.

LIST OF REFERENCE SIGNS

(80) 10 fuel cell 12 first fuel cell region 14 second fuel cell region 16 gas channel 18 first gas channel 20 second gas channel 22 construction axis 24 ion-conductive separating layer 26 insulation layer 28 electrode coating 30 fuel cell 32 fuel cell region 34 first fuel cell region 36 second fuel cell region 38 first gas channel 40 second gas channel 42 construction axis 44 gas channel curvature region 46 gas channel plane region 48 gas inlet region 50 gas outlet region 52 electrode coating 54 fuel cell 56 first distribution tube 58 second distribution tube 60 gas supply region 62 gas discharge region 64 subsection 66 fuel cell 68 interconnector sheet 70 fuel cell region 71 contact tongue 72 connection region 74 connection axis 76 connection opening 78 band-like region 80 holding eye 81 holding device 82 fastening knobs 84 aperture 86 interconnector sheet blank 88 fuel cell system 90 fuel cell 92 first fuel cell region 94 second fuel cell region 96 electrode coating 98 gas channel curvature region 100 gas channel plane region 102 first distribution tube 104 second distribution tube 106 gas supply region 108 gas discharge region 110 aperture 112 holding device 114 winding structure 116 conductive element 118 groove 120 interconnector sheet 122 contact tongue 124 electrical connection region 126 clamping region