Stack, hot module, and hydrogen production apparatus

Abstract

To provide a stack, a hot module, and a hydrogen production device capable of improving durability of a cell.SOLUTION: The stack includes a stack body in which reaction units are arranged side by side, each of the reaction units including a cell containing an electrolyte separating a fuel electrode and an air electrode from each other in a thickness direction, and a fuel chamber including the fuel electrode. The fuel cell stack includes a first manifold for supplying fuel gas to a fuel electrode, two conductive plates disposed outside in a thickness direction of a laminate and electrically connected to reaction units and having different polarities, and two terminals connected to each of the conductive plates and protruding from a first edge of the laminate, wherein a distance between a second edge of the conductive plate facing the first edge and the fuel electrode is shorter than a distance between the first edge and the fuel electrode.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a stack in which cells are stacked, a hot module, and a hydrogen production device. [Background technology]

[0002] In a stack having cells containing an electrolyte that separates the fuel electrode and the air electrode in the thickness direction, the prior art disclosed in Patent Document 1 provides a layer that captures contaminants in the oxidant gas in order to improve the durability of the cell, thereby reducing poisoning of the air electrode. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-67509 Summary of the Invention [Problem to be solved by the invention]

[0004] As in the prior art, there is a demand for improved cell durability.

[0005] The present invention has been made to meet this demand, and an object of the present invention is to provide a stack, a hot module, and a hydrogen production device that can improve the durability of the cells. [Means for solving the problem]

[0006] A first aspect to achieve this object is a stack comprising: a stack of three or more reaction units arranged in a line in the thickness direction, each reaction unit including a cell containing an electrolyte separating an anode and an cathode in the thickness direction, and a fuel chamber including an anode, the reaction units being connected in series to one another; a first manifold extending in the thickness direction of the stack, connected to the fuel chamber provided in each reaction unit, and supplying fuel gas to the anode; a second manifold extending in the thickness direction of the stack, connected to the fuel chamber provided in each reaction unit, and discharging the fuel gas supplied to the anode; two conductive plates of different polarities arranged on the outside of the stack in the thickness direction and electrically connected to the reaction units; and two terminals connected to each of the conductive plates and protruding outside the stack from first edges of the conductive plates, wherein the distance between the second edge of the conductive plate facing the first edge and the anode is shorter than the distance between the first edge and the anode of the reaction unit adjacent to the conductive plate.

[0007] In a second embodiment, the two terminals in the first embodiment protrude in the same direction, and the distance between the boundary between the first manifold and the fuel chamber and the first edge is shorter than the distance between the boundary between the second manifold and the fuel chamber and the first edge.

[0008] In a third aspect, in the first aspect, the two terminals protrude in the same direction, and the distance between the boundary between the second manifold and the fuel chamber and the first edge is shorter than the distance between the boundary between the first manifold and the fuel chamber and the first edge.

[0009] In a fourth aspect, in any of the first to third aspects, the fuel electrode of the reaction unit adjacent to the conductive plate is located farther from the periphery of the stack from which the two terminals protrude than the fuel electrode of the reaction unit located in the center of the row of reaction units.

[0010] In a fifth aspect, in any one of the first to fourth aspects, the cell has a function of electrolyzing a fuel gas.

[0011] The sixth aspect is a hot module comprising a stack according to any one of the first to fifth aspects, a vaporizer that generates steam as a fuel gas, a heat exchanger that exchanges heat with the gas supplied to the stack, a heater for heating the stack, and insulation within which the stack, vaporizer, heat exchanger, and heater are disposed.

[0012] A seventh aspect is a hydrogen production device, which includes the hot module according to the sixth aspect. [Effects of the Invention]

[0013] According to the present invention, in the reaction unit adjacent to the conductive plate, the distance between the fuel electrode and the second edge of the conductive plate facing the first edge of the conductive plate on which the terminal is provided is shorter than the distance between the first edge and the fuel electrode. Compared to when the distance between the first edge and the fuel electrode is equal to the distance between the second edge and the fuel electrode, Joule heat from the terminal is less likely to be transferred to the fuel electrode, thereby reducing the temperature variation of the fuel electrode. Because the variation in the reaction of the fuel electrode can be reduced, the durability of the cell can be improved. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 2 is a perspective view of a stack according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the stack taken along line II-II. [Figure 3] FIG. 3 is a cross-sectional view of the stack taken along line III-III. [Figure 4] FIG. 10 is a cross-sectional view of a stack according to a second embodiment. [Figure 5] FIG. 1 is a cross-sectional view of the stack taken along line VV. [Figure 6] FIG. 1 is a block diagram of a hydrogen production device. DETAILED DESCRIPTION OF THE INVENTION

[0015] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Fig. 1 is a perspective view of a stack 10 in one embodiment. The stack 10 includes a reaction unit 11, a stack 12 formed by stacking a plurality of reaction units 11 in the thickness direction, conductive plates 13 and 15 electrically connected to the stack 12, and end plates 17 and 18 that sandwich the stack 12 and the conductive plates 13 and 15 in the thickness direction. The stack 12 is formed by stacking, for example, approximately 10-30 reaction units 11.

[0016] Conductive plate 13 is disposed between laminate 12 and end plate 17, and conductive plate 15 is disposed between laminate 12 and end plate 18. Terminals 14 and 16 are connected to conductive plates 13 and 15, respectively. Stainless steel is an example of the material for conductive plates 13 and 15 and terminals 14 and 16. In this embodiment, terminals 14 and 16 protrude in the same direction.

[0017] An insulator 19 disposed between the conductive plate 13 and the end plate 17 electrically insulates the conductive plate 13 from the end plate 17. An insulator 20 disposed between the conductive plate 15 and the end plate 18 electrically insulates the conductive plate 15 from the end plate 18. Bolts 21 are disposed around the periphery of the stack 10 and pass through the end plates 17, 18, insulators 19, 20, conductive plates 13, 15, and laminate 12 in the thickness direction. The stack 10 is fastened together by the bolts 21.

[0018] The four spaces that penetrate the periphery of the stack 10 in the thickness direction function as a first manifold 22 that supplies fuel gas from outside the stack 10 to a fuel chamber 36 (described later) of the reaction unit 11, a second manifold 23 that discharges gas from the fuel chamber 36 to outside the stack 10, a third manifold 24 that supplies oxidant gas from outside the stack 10 to an air chamber 37 (described later) of the reaction unit 11, and a fourth manifold 25 that discharges gas from the air chamber 37 to outside the stack 10.

[0019] The first manifold 22 passes through the end plate 18, the insulator 20, and the conductive plate 15, and is closed by the end plate 17, the insulator 19, and the conductive plate 13. The fuel gas supplied to the stack 10 flows through the first manifold 22 from the end plate 18 to the end plate 17.

[0020] In this embodiment, the second manifold 23 penetrates the end plate 18, the insulator 20, and the conductive plate 15, and is closed by the end plate 17, the insulator 19, and the conductive plate 13. Similarly, the third manifold 24 penetrates the end plate 18, the insulator 20, and the conductive plate 15, and is closed by the end plate 17, the insulator 19, and the conductive plate 13. The fourth manifold 25 penetrates the end plate 18, the insulator 20, and the conductive plate 15, and is closed by the end plate 17, the insulator 19, and the conductive plate 13.

[0021] Figure 2 is a cross-sectional view of the stack 10 taken along line II-II in Figure 1, which passes through the manifolds 22 and 23. Figure 2 mainly illustrates the reaction unit 11a adjacent to the conductive plate 13, the reaction unit 11b adjacent to the conductive plate 15, and the reaction unit 11c located in the center of the row of reaction units 11, and does not illustrate the others. In Figure 2, the thickness of each part is exaggerated.

[0022] Reaction unit 11a is the reaction unit 11 located closest to conductive plate 13. Reaction unit 11b is the reaction unit 11 located closest to conductive plate 15. When the number of reaction units 11 included in stack 12 is odd, reaction unit 11c is one reaction unit 11 located in the middle of the arrangement of stack 12. When the number of reaction units 11 included in stack 12 is even, reaction unit 11c is two reaction units 11 located in the middle of the arrangement of stack 12.

[0023] 2, the reaction unit 11 includes, in order in the thickness direction, an anode frame 26, a first separator 27, an air electrode frame 28, and a second separator 29. Manifolds 22-25 penetrate the anode frame 26, the first separator 27, the air electrode frame 28, and the second separator 29. Cells 30, interconnectors 34, and current collectors 35 are arranged inside the anode frame 26, the first separator 27, the air electrode frame 28, and the second separator 29.

[0024] The cell 30 includes an electrolyte 31, and an anode 32 and cathode 33 separated in the thickness direction by the electrolyte 31. In this embodiment, a flat-plate type cell 30 is described, but the present invention is not limited to this. The cell 30 may be a metal-supported type (metal-supported flat-plate type) in which the electrodes and electrolyte are supported by a porous body of a metal such as an Fe-Cr-based metal. The cell 30 may be an electrode-supported type or an electrolyte-supported type.

[0025] The electrolyte 31 is made of a solid oxide, and examples thereof include stabilized zirconia, ceria-based solid solution, and a solid solution of alumina with one or more selected from stabilized zirconia and ceria-based solid solutions. Examples of stabilizers for stabilized zirconia include CaO, MgO, YO, ScO, and YbO. Examples of elements dissolved in ceria in ceria-based solid solutions include Gd, Sm, and Y.

[0026] Examples of the material for the fuel electrode 32 include a material containing a catalyst containing Ni and zirconia with Y dissolved therein, and a material containing a catalyst containing Ni and ceria with Gd dissolved therein. Examples of the catalyst include Ni, Ni-based alloys, and cermet, which is a composite (sintered body) of NiO and an oxide (solid electrolyte).

[0027] The material of the cathode 33 is a perovskite oxide called La 1-X Sr X MnO 3-δ ,La 1-X Sr X CoO 3-δ ,La 1-X Sr X Co 1-Y Fe Y O 3-δ,Pr 1-X Sr X MnO 3-δ is exemplified.

[0028] The fuel electrode frame 26 is a frame-shaped member disposed between the second separator 29 and the first separator 27, and surrounds the cells 30 and the current collector 35. Stainless steel is an example of the material for the fuel electrode frame 26. The first separator 27 is a frame-shaped member, and is airtightly joined to the electrolyte 31 with brazing material or the like, avoiding the air electrode 33. Stainless steel is an example of the material for the first separator 27.

[0029] The cathode frame 28 is a frame-shaped member disposed between the first separator 27 and the second separator 29, and surrounds the interconnector 34. An example of the material for the cathode frame 28 is an insulator such as mica. The second separator 29 is a frame-shaped member, and is airtightly joined to the interconnector 34 with a brazing material or the like. An example of the material for the second separator 29 is stainless steel.

[0030] The current collector 35 electrically connects the interconnector 34 and the anode 32 that are adjacent in the thickness direction. The current collector 35 is exemplified by one that includes a bent conductor that contacts the interconnector 34 and the anode 32, and an insert that is placed in the conductor. Examples of the material for the conductor include metals such as nickel, nickel-based alloys, and stainless steel. Examples of the material for the insert include an insulator such as mica. The interconnector 34 electrically connects the current collector 35 and the cathode 33 that are adjacent in the thickness direction. Examples of the material for the interconnector 34 are stainless steel.

[0031] A fuel chamber 36 is provided inside the anode frame 26, and an air chamber 37 is provided inside the cathode frame 28. Slits 38 and 39 are provided in the anode frame 26. The fuel chamber 36 is connected to the first manifold 22 by the slit 38, and to the second manifold 23 by the slit 39. The air chamber 37 is connected to the third manifold 24 and the fourth manifold 25 (see FIG. 1). The first separator 27 and the second separator 29 isolate the fuel chamber 36 and the air chamber 37, preventing the fuel gas in the fuel chamber 36 and the oxidizer gas in the air chamber 37 from mixing.

[0032] When the stack 10 is a fuel cell, examples of the fuel gas include hydrogen, carbon monoxide, and hydrocarbon, and examples of the oxidant gas include oxygen and air. When the stack 10 is an electrolysis device (the cell 30 is an electrolysis cell having the function of electrolyzing the fuel gas), examples of the fuel gas include water vapor, carbon dioxide, and a mixture thereof, and examples of the oxidant gas include oxygen and air. The stack 10 also includes one that is capable of reversible operation as a fuel cell and an electrolysis device.

[0033] The multiple cells 30 are electrically connected in series between terminals 14 and 16 via conductive materials such as interconnectors 34 and current collectors 35. When the stack 10 is an electrolysis device, the positive electrode of a power supply (not shown) is connected to terminal 14, and the negative electrode of the power supply is connected to terminal 16, causing electrons to flow toward the fuel electrode 32 of each cell 30. Fuel gas entering the fuel chamber 36 from the first manifold 22 is reduced at the fuel electrode 32. Because electrons are removed at the air electrode 33, oxide ions that have migrated to the air electrode 33 via the electrolyte 31 are oxidized at the air electrode 33. As a result, energy carriers such as hydrogen and hydrocarbons are generated in the fuel chamber 36. The energy carriers generated in the fuel chamber 36 are exhausted to the outside of the stack 10 through the second manifold 23.

[0034] When stack 10 is a fuel cell, fuel gas is flowed from first manifold 22 to fuel chamber 36, and oxidant gas is flowed from third manifold 24 to air chamber 37. Gas-phase oxygen reacts with electrons at air electrode 33 of cell 30 to generate oxide ions, and the oxide ions that have traveled through electrolyte 31 react with fuel gas at fuel electrode 32 to generate electrons. This causes a current to flow through a load (not shown) connected to terminals 14 and 16.

[0035] The terminal 14 protrudes from a first edge 40 of the conductive plate 13 to the outside of the reaction unit 11. A second edge 41 of the conductive plate 13 opposite the first edge 40 overlaps the edge of the reaction unit 11. The terminal 16 protrudes from a first edge 42 of the conductive plate 15 to the outside of the reaction unit 11. A second edge 43 of the conductive plate 15 opposite the first edge 42 overlaps the edge of the reaction unit 11.

[0036] In this embodiment, the planar shape of the conductive plates 13 and 15 is a quadrangle including four sides. The first edge 40 and the second edge 41 of the conductive plate 13 are opposite sides, and the first edge 42 and the second edge 43 of the conductive plate 15 are opposite sides. The corners of the conductive plates 13 and 15 where the sides of the planar shape intersect may be chamfered or rounded.

[0037] FIG. 3 is a cross-sectional view of the stack 10 taken along line III-III in FIG. 2, showing the reaction unit 11b adjacent to the conductive plate 15. In the reaction unit 11b adjacent to the conductive plate 15, the distance D3 between the first edge 42 of the conductive plate 15 (see FIG. 2) on which the terminal 16 is provided and the anode 32 is longer than the distance D4 between the second edge 43 of the conductive plate 15 (see FIG. 2) facing the first edge 42 and the anode 32. Compared to when the distances D3 and D4 are equal, the Joule heat generated at the terminal 16 during stack 10 operation is less likely to be transferred to the anode 32. This reduces the temperature variation within the anode 32 due to the Joule heat of the terminal 16. This reduces the variation in the reaction within the anode 32, thereby reducing the occurrence of areas of significant degradation in the anode 32. This improves the durability of the cell 30 including the anode 32.

[0038] The distance D6 between the first edge 42 and the boundary between the first manifold 22 and the fuel chamber 36 is shorter than the distance D7 between the first edge 42 and the boundary between the second manifold 23 and the fuel chamber 36. Compared to when the distance D7 is longer than the distance D6, the Joule heat of the terminal 16 is more easily transferred to the fuel gas flowing through the first manifold 22.

[0039] Returning to Figure 2, terminal 14 protrudes in the same direction as terminal 16. Because Joule heat from terminal 14 is easily transferred to the fuel gas flowing through first manifold 22, the Joule heat from terminals 14 and 16 can be used to heat the fuel gas supplied to fuel chamber 36. Because the temperature of the fuel gas increases, the reaction at fuel electrode 32 can be promoted.

[0040] In the reaction unit 11a adjacent to the conductive plate 13, the distance D1 between the first edge 40 of the conductive plate 13, on which the terminal 14 is provided, and the anode 32 is longer than the distance D2 between the second edge 41 of the conductive plate 13 facing the first edge 40 and the anode 32. Compared to when the distances D1 and D2 are equal, Joule heat generated at the terminal 14 when the stack 10 is operated is less likely to be transferred to the anode 32, thereby reducing the temperature variation within the surface of the anode 32 caused by the Joule heat of the terminal 14. Because the variation in the reaction within the surface of the anode 32 can be reduced, the occurrence of significantly deteriorated portions of the anode 32 can be reduced. This improves the durability of the cell 30 including the anode 32.

[0041] It is desirable to make the distance D1 of not only the reaction units 11a adjacent to the conductive plate 13 but also the reaction units 11 close to the conductive plate 13 longer than the distance D2. This is because the reaction units 11 close to the conductive plate 13 are affected by Joule heat from the terminal 14. The number of reaction units 11 close to the conductive plate 13 that make the distance D1 longer than the distance D2 can be about 20% of the total number of reaction units 11 included in the laminate 12.

[0042] Similarly, it is desirable to make the distance D3 of not only the reaction unit 11b adjacent to the conductive plate 15 but also the reaction units 11 close to the conductive plate 15 longer than the distance D4. This is because the reaction units 11 close to the conductive plate 15 are affected by Joule heat from the terminal 16. When the distance D3 is made longer than the distance D4, the number of reaction units 11 close to the conductive plate 15 can be about 20% of the total number of reaction units 11 included in the laminate 12.

[0043] The fuel electrode 32 of reaction unit 11a adjacent to conductive plate 13 and the fuel electrode 32 of reaction unit 11b adjacent to conductive plate 15 are located farther from the periphery 44 of stack 12 from which terminals 14 and 16 protrude than the fuel electrode 32 of reaction unit 11c located in the center of the row of reaction units 11. Specifically, distances D1 and D3 are longer than the distance D5 between periphery 44 and fuel electrode 32. This reduces the temperature variation within the plane of fuel electrode 32 of reaction units 11a and 11b due to the addition of Joule heat from terminals 14 and 16, thereby reducing the reaction variation within the plane of fuel electrode 32.

[0044] When the number of reactive units 11 contained in the stack 12 is even, reactive unit 11c is the two reactive units 11 located in the middle of the arrangement of the stack 12, and therefore distance D5 is the average of the distances D5 of the two reactive units 11.

[0045] There are no restrictions on the relationship between distance D5 between periphery 44 of laminate 12 and fuel electrode 32 and distance D8 between the periphery of laminate 12 facing periphery 44 and the fuel electrode. However, by making distance D5 shorter than distance D8, Joule heat from terminals 14 and 16 is more easily transferred to fuel electrode 32 of reaction unit 11c than when distance D5 is longer than distance D8, and the electrode reaction in reaction unit 11c can be promoted.

[0046] A second embodiment will be described with reference to Figures 4 and 5. In the first embodiment, the stack 10 was described in which the terminals 14, 16 protruded near the first manifold 22. In contrast, in the second embodiment, a stack 45 will be described in which the terminals 14, 16 protruded near the second manifold 23. In the second embodiment, the same parts as those described in the first embodiment are designated by the same reference numerals, and the following description will be omitted.

[0047] Fig. 4 is a cross-sectional view of a stack 45 according to the second embodiment. Fig. 5 is a cross-sectional view of the stack 45 taken along line VV in Fig. 4, through a reaction unit 11b adjacent to the conductive plate 15. The terminals 14 and 16 protrude in the same direction.

[0048] The distance D9 between the boundary between the second manifold 23 and the fuel chamber 36 and the first edge 42 is shorter than the distance D10 between the boundary between the first manifold 22 and the fuel chamber 36 and the first edge 42. Therefore, Joule heat from the terminal 16 is easily transferred downstream of the fuel gas flowing through the fuel chamber 36 from the first manifold 22 to the second manifold 23. Although the fuel gas concentration is lower downstream of the fuel gas than upstream of the fuel gas, the Joule heat from the terminal 16 heats the anode 32 downstream of the fuel gas, thereby promoting the reaction at the anode 32 downstream of the fuel gas. This reduces the variation in the reaction within the surface of the anode 32, thereby reducing the occurrence of significantly deteriorated portions of the anode 32. This improves the durability of the cell 30, including the anode 32.

[0049] 5 is a block diagram of a hydrogen production device 50 including the stack 10. The hydrogen production device 50 is a device that produces hydrogen from water and includes a hot module 51.

[0050] The hot module 51 includes the stack 10, a vaporizer 52 that generates steam to be supplied to the stack 10, a heat exchanger 53 that exchanges heat between the gas supplied to the stack 10 and the gas generated by the stack 10, and a heater 54 that heats the stack 10. In the hot module 51, the stack 10, the vaporizer 52, the heat exchanger 53, and the heater 54 are arranged inside a heat insulating material 55 to reduce heat radiation.

[0051] The vaporizer 52 includes a heat exchanger that exchanges heat with the high-temperature gas containing oxygen produced by the stack 10, and heats water to produce steam. The steam produced by the vaporizer 52 contains hydrogen, which reduces oxidation of the catalyst contained in the anode 32. The hydrogen-containing steam exchanges heat with the hydrogen and oxygen produced by the stack 10 in the heat exchanger 53, is then heated by the heater 54 to the operating temperature of the stack 10, and is supplied to the fuel chamber 36 of the stack 10. The air exchanges heat with the hydrogen and oxygen produced by the stack 10 in the heat exchanger 53, is then heated by the heater 54 to the operating temperature of the stack 10, and is supplied to the air chamber 37 of the stack 10.

[0052] Examples of heat insulating material 55 include heat-resistant fibers such as ceramic wool, refractory ceramic fiber (RCF), and biosoluble fiber (AES), and a heat-resistant container made of heat-resistant fibers. The heat-resistant fibers fill gaps between stack 10, vaporizer 52, heat exchanger 53, and heater 54. Condenser 56 is a device that cools hydrogen gas, and liquefied water is supplied to vaporizer 52 as raw water.

[0053] When the stack 10 is used in the hydrogen production device 50, the variation in the reaction within the surface of the fuel electrode 32 can also be reduced, thereby improving the durability of the cell 30. The same applies when the stack 45 is used in the hydrogen production device 50 instead of the stack 10.

[0054] The present invention has been described above based on the embodiments, but the present invention is not limited to the above embodiments, and it can be easily inferred that various improvements and modifications are possible within the scope of the present invention.

[0055] In the embodiment, the first manifold 22 penetrates the end plate 18, the insulator 20, and the conductive plate 15, and is closed by the end plate 17, the insulator 19, and the conductive plate 13, and the fuel gas supplied to the stack 10 flows through the first manifold 22 from the end plate 18 to the end plate 17. However, this is not necessarily limited to this. It is of course possible for the first manifold 22 to penetrate the end plate 17, the insulator 19, and the conductive plate 13, and be closed by the end plate 18, the insulator 20, and the conductive plate 15. In this case, the fuel gas supplied to the stack 10 flows through the first manifold 22 from the end plate 17 to the end plate 18.

[0056] In the embodiment, the second manifold 23 penetrates the end plate 18, the insulator 20, and the conductive plate 15, is closed by the end plate 17, the insulator 19, and the conductive plate 13, and the gas flows through the second manifold 23 from the end plate 17 to the end plate 18 and is exhausted to the outside of the stack 10. However, this is not necessarily limited to this. It is of course possible for the second manifold 23 to penetrate the end plate 17, the insulator 19, and the conductive plate 13, and be closed by the end plate 18, the insulator 20, and the conductive plate 15. In this case, the gas flows through the second manifold 23 from the end plate 18 to the end plate 17 and is exhausted to the outside of the stack 10. The directions of the gas flowing through the third manifold 24 and the fourth manifold 25 are also set appropriately.

[0057] In the embodiment, the fuel chambers 36 are connected in parallel to the first manifold 22 and the second manifold 23, but this is not necessarily limited to this. For example, as in the stack disclosed in Japanese Patent Application Laid-Open No. 2017-228481, it is of course possible to connect the fuel chambers 36 to the first manifold 22 and the second manifold 23 so that the flow of fuel gas is in parallel and serial.

[0058] In the embodiment, the terminals 14, 16 protrude in the same direction from the laminate 12, but this is not necessarily limited to this. It is of course possible to arrange the conductive plates 13, 15 on the laminate 12 so that the terminals 14, 16 protrude in different directions.

[0059] In the embodiment, the case where the shape of the cells 30 is a rectangle has been described, but this is not necessarily limited to this. The shape of the cells 30 may be a circle or an ellipse, or may be a polygon other than a rectangle, such as a triangle or a pentagon.

[0060] In the embodiment, the manifolds 22, 23, 24, and 25 through which gas passes are built into the stack 10, but this is not necessarily limited to this. It is of course possible to provide manifolds such as the manifolds 22, 23, 24, and 25 outside the cells by joining them to the cells. Examples of materials for the manifolds include ceramics with high high-temperature strength.

[0061] In the embodiment, the stack 10 including the solid oxide type cells 30 has been described, but this is not necessarily limited to this. It is of course possible to apply the technology according to the embodiment to a stack including other types of cells, such as a molten carbonate type. [Explanation of symbols]

[0062] 10,45 stack 11 Reaction Units 12 Laminate 13,15 Conductive plate 14,16 terminals 22 First manifold 23 Second Manifold 30 cells 31 Electrolytes 32 Fuel electrode 33 Air electrode 36 Fuel chamber 40,42 First Edge 41,43 Second Edge 44 laps 50 Hydrogen production equipment 51 Hot Module 52 Vaporizer 53 Heat exchanger 54 Heater 55 Insulation

Claims

1. a cell including an electrolyte separating an anode and a cathode through its thickness; a stack in which three or more reaction units each including a fuel chamber including the anode are arranged side by side in the thickness direction and the reaction units are connected in series to each other; a first manifold extending in the thickness direction of the stack, connected to the fuel chamber provided in each of the reaction units, and supplying a fuel gas to the fuel electrode; a second manifold extending in the thickness direction of the stack, connected to the fuel chamber provided in each of the reaction units, and discharging the fuel gas supplied to the anode; two conductive plates having different polarities and arranged on the outer sides of the laminate in the thickness direction and electrically connected to the reaction units; two terminals connected to each of the conductive plates and projecting out of the stack from a first edge of the conductive plate, A stack in which the reaction unit adjacent to the conductive plate has a distance between the second edge of the conductive plate facing the first edge and the anode shorter than the distance between the first edge and the anode.

2. The two terminals protrude in the same direction, The stack according to claim 1 , wherein a distance between the boundary between the first manifold and the fuel chamber and the first edge is shorter than a distance between the boundary between the second manifold and the fuel chamber and the first edge.

3. The two terminals protrude in the same direction, The stack according to claim 1 , wherein a distance between the boundary between the second manifold and the fuel chamber and the first edge is shorter than a distance between the boundary between the first manifold and the fuel chamber and the first edge.

4. 4. A stack as described in claim 2 or 3, wherein the fuel electrode of the reaction unit adjacent to the conductive plate is located farther from the periphery of the stack from which the two terminals protrude than the fuel electrode of the reaction unit located in the center of the arrangement of the reaction units.

5. 4. The stack according to claim 1, wherein the cells have a function of electrolyzing the fuel gas.

6. A stack according to any one of claims 1 to 3; a vaporizer for generating water vapor as the fuel gas; a heat exchanger that exchanges heat with the gas supplied to the stack; a heater for heating the stack; a hot module comprising a thermal insulator in which the stack, the vaporizer, the heat exchanger, and the heater are disposed;

7. A hydrogen production device comprising the hot module according to claim 6.

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