Stack, hot module, and hydrogen production apparatus

Abstract

To provide a stack, a hot module, and a hydrogen production device capable of improving durability.SOLUTION: The stack includes a stack body in which three or more reaction units are arranged side by side in a thickness direction and the reaction units are connected to each other in series, each of the reaction units including a cell containing an electrolyte separating a fuel electrode and an air electrode from each other in the thickness direction, and a fuel chamber including the fuel electrode. When the reaction unit is partitioned into a central portion located at the center of the arrangement of the reaction units, an upstream portion of the fuel gas with respect to the central portion, and a downstream portion of the fuel gas with respect to the central portion, a distance between the fuel electrode and a boundary between the fuel chamber and the manifold in the downstream portion is shorter than a distance between the fuel electrode and the boundary between the fuel chamber and the manifold in the central portion.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 durability, 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 stack 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 durability. [Means for solving the problem]

[0006] A first aspect for achieving this object is a stack comprising a stack in which three or more reaction units, each including a cell containing an electrolyte that separates an anode and an cathode in the thickness direction and a fuel chamber including an anode, are arranged in a line in the thickness direction and connected in series to each other, and a manifold extending in the thickness direction of the stack, connected to a fuel chamber provided in each of the reaction units, and supplying fuel gas flowing from one side to the other in the thickness direction to the anode, wherein when the reaction units are divided into a central portion located in the center of the arrangement of reaction units, an upstream portion of the fuel gas relative to the central portion, and a downstream portion of the fuel gas relative to the central portion, the distance between the boundary between the fuel chamber and the manifold and the anode in the downstream portion is shorter than the distance between the boundary between the fuel chamber and the manifold and the anode in the central portion.

[0007] The second aspect is a stack comprising a stack in which three or more reaction units, each including a cell containing an electrolyte that separates an anode and an cathode in the thickness direction and a fuel chamber including an anode, are arranged in a line in the thickness direction and connected in series to each other, and a manifold extending in the thickness direction of the stack, connected to a fuel chamber provided in each of the reaction units, and supplying fuel gas flowing from one side to the other in the thickness direction to the anode, wherein when the reaction units are divided into a central portion located in the center of the arrangement of reaction units, an upstream portion of the fuel gas relative to the central portion, and a downstream portion of the fuel gas relative to the central portion, the distance between the boundary between the fuel chamber and the manifold and the anode in the upstream portion is longer than the distance between the boundary between the fuel chamber and the manifold and the anode in the central portion.

[0008] In a third aspect, in the first aspect, the distance between the fuel electrode and the boundary between the fuel chamber and the manifold in the upstream portion is longer than the distance between the fuel electrode and the boundary between the fuel chamber and the manifold in the central portion.

[0009] In a fourth aspect, in any one of the first to third aspects, the cell has a function of electrolyzing a fuel gas.

[0010] The fifth aspect is a hot module comprising a stack according to any one of the first to fourth 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 in which the stack, vaporizer, heat exchanger, and heater are disposed.

[0011] A sixth aspect is a hydrogen production device, which includes the hot module according to the fifth aspect. [Effects of the Invention]

[0012] According to the present invention, the distance between the boundary between the fuel chamber and the manifold and the anode in the downstream section is shorter than the distance between the boundary between the fuel chamber and the manifold and the anode in the central section, thereby reducing the difference between the distance between the manifold inlet and the anode in the downstream section and the distance between the manifold inlet and the anode in the central section. Since the difference between the fuel gas concentration at the anode in the downstream section and the fuel gas concentration at the anode in the central section can be reduced, the difference between the output of the cells in the downstream section and the output of the cells in the central section can be reduced. Since the cells in the downstream section can be prevented from continuing to operate with low-concentration fuel gas, deterioration of the cells in the downstream section can be reduced. This improves the durability of the stack.

[0013] Furthermore, because the distance between the boundary between the fuel chamber and the manifold and the anode in the upstream section is longer than the distance between the boundary between the fuel chamber and the manifold and the anode in the central section, the difference between the distance between the inlet of the manifold and the anode in the upstream section and the distance between the inlet of the manifold and the anode in the central section can be reduced. Since the difference between the fuel gas concentration at the anode in the central section and the fuel gas concentration at the anode in the upstream section can be reduced, the difference between the output of the cells in the central section and the output of the cells in the upstream section can be reduced. Since the output of any particular cell between the central and upstream sections can be prevented from becoming excessive, the durability of the stack can be improved. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 2 is a perspective view of a stack according to one embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the laminate taken along line II-II. [Figure 3] FIG. 3 is a cross-sectional view of the laminate taken along line III-III. [Figure 4] 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. The conductive plates 13 and 15 and terminals 14 and 16 can be made of stainless steel, for example.

[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 manifold 22 that supplies fuel gas from outside the stack 10 to a fuel chamber 39 (described later) of the reaction unit 11, a manifold 23 that discharges gas from the fuel chamber 39 to outside the stack 10, a manifold 24 that supplies oxidant gas from outside the stack 10 to an air chamber 41 (described later) of the reaction unit 11, and a manifold 25 that discharges gas from the air chamber 41 to outside the stack 10.

[0019] Manifold 22 passes through end plate 18, insulator 20, and conductive plate 15, and is closed by end plate 17, insulator 19, and conductive plate 13. Fuel gas supplied to stack 10 flows through manifold 22 from end plate 18 to end plate 17. For ease of explanation, reaction units 11 are divided into three sections: a central section 26 located in the center of the row of reaction units 11, an upstream section 27 of the fuel gas relative to central section 26, and a downstream section 28 of the fuel gas relative to central section 26.

[0020] When the number of reaction units 11 is a multiple of three, the stack 12 is divided into three sections so that the number of reaction units 11 contained in the central section 26, the number of reaction units 11 contained in the upstream section 27, and the number of reaction units 11 contained in the downstream section 28 are equal. When the number of reaction units 11 is not a multiple of three, the number of reaction units 11 is divided by 3 to obtain the quotient and remainder, and the remainder is then allocated to the central section 26, the upstream section 27, or the downstream section 28 so that the number of reaction units 11 contained in the upstream section 27 and the number of reaction units 11 contained in the downstream section 28 are equal. The reason for making the number of reaction units 11 contained in the upstream section 27 and the number of reaction units 11 contained in the downstream section 28 equal is to fairly evaluate the reaction units 11 contained in the upstream section 27 and the downstream section 28.

[0021] For example, when the remainder when the number of reaction units 11 is divided by 3 is 1, the number of reaction units 11 contained in the upstream section 27 and the number of reaction units 11 contained in the downstream section 28 are each set as the quotient, and the number of reaction units 11 contained in the central section 26 is set as the quotient plus the remainder of 1. When the remainder when the number of reaction units 11 is divided by 3 is 2, the number of reaction units 11 contained in the central section 26 is set as the quotient, and the number of reaction units 11 contained in the upstream section 27 and the number of reaction units 11 contained in the downstream section 28 are each set as the quotient plus 1.

[0022] In this embodiment, manifold 23 penetrates end plate 18, insulator 20, and conductive plate 15, and is closed by end plate 17, insulator 19, and conductive plate 13. Similarly, manifold 24 penetrates end plate 18, insulator 20, and conductive plate 15, and is closed by end plate 17, insulator 19, and conductive plate 13. Manifold 25 penetrates end plate 18, insulator 20, and conductive plate 15, and is closed by end plate 17, insulator 19, and conductive plate 13.

[0023] 2 is a cross-sectional view of the laminate 12 taken along line II-II in FIG. 1, which passes through the manifolds 22 and 23, and illustrates the upstream portion 27 and part of the downstream portion 28 of the laminate 12, as well as the central portion 26. In FIG. 2, the thickness of each portion is exaggerated.

[0024] 2, the reaction unit 11 includes, in order in the thickness direction, an anode frame 29, a first separator 30, an air electrode frame 31, and a second separator 32. Manifolds 22-25 penetrate the anode frame 29, the first separator 30, the air electrode frame 31, and the second separator 32. Cells 33, interconnectors 37, and current collectors 38 are arranged inside the anode frame 29, the first separator 30, the air electrode frame 31, and the second separator 32.

[0025] The cell 33 includes an electrolyte 34, and an anode 35 and cathode 36 separated in the thickness direction by the electrolyte 34. In this embodiment, a flat-plate type cell 33 is described, but the present invention is not limited to this. The cell 33 may also 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 33 may be an electrode-supported type or an electrolyte-supported type.

[0026] The electrolyte 34 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, Sc, and Yb. Examples of elements that dissolve in ceria in ceria-based solid solutions include Gd, Sm, and Y.

[0027] Examples of the material for the fuel electrode 35 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).

[0028] The material of the cathode 36 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.

[0029] The fuel electrode frame 29 is a frame-shaped member disposed between the second separator 32 and the first separator 30, and surrounds the cells 33 and the current collectors 38. Stainless steel is an example of the material for the fuel electrode frame 29. The first separator 30 is a frame-shaped member, and is airtightly joined to the electrolyte 34 with brazing material or the like, avoiding the air electrode 36. Stainless steel is an example of the material for the first separator 30.

[0030] The cathode frame 31 is a frame-shaped member disposed between the first separator 30 and the second separator 32, and surrounds the interconnector 37. An example of the material for the cathode frame 31 is an insulator such as mica. The second separator 32 is a frame-shaped member, and is airtightly joined to the interconnector 37 with a brazing material or the like. An example of the material for the second separator 32 is stainless steel.

[0031] The current collector 38 electrically connects the interconnector 37 and the anode 35 adjacent to each other in the thickness direction. The current collector 38 is exemplified by one including a bent conductor that contacts the interconnector 37 and the anode 35, and an insert 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 37 electrically connects the current collector 38 and the cathode 36 adjacent to each other in the thickness direction. Examples of the material for the interconnector 37 include stainless steel.

[0032] A fuel chamber 39 is provided inside the anode frame 29, and an air chamber 41 is provided inside the cathode frame 31. Slits 40 and 42 are provided in the anode frame 29. The fuel chamber 39 is connected to the manifold 22 by the slit 40, and to the manifold 23 by the slit 42. The air chamber 41 is connected to the manifolds 24 and 25 (see FIG. 1). The first separator 30 and the second separator 32 isolate the fuel chamber 39 from the air chamber 41, preventing the fuel gas in the fuel chamber 39 and the oxidizer gas in the air chamber 41 from mixing.

[0033] When 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 stack 10 is an electrolysis device (cell 33 is an electrolysis cell having the function of electrolyzing fuel gas), examples of the fuel gas include water vapor, carbon dioxide, and a mixed gas thereof, and examples of the oxidant gas include oxygen and air. Stack 10 also includes stacks that are capable of reversible operation as a fuel cell and an electrolysis device.

[0034] The multiple cells 33 are electrically connected in series between terminals 14, 16 via interconnectors 37 and current collectors 38. 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 35 of the cell 33. The fuel gas that enters the fuel chamber 39 is reduced at the fuel electrode 35. Because electrons are removed at the air electrode 36, oxide ions that have migrated to the air electrode 36 via the electrolyte 34 are oxidized at the air electrode 36. As a result, energy carriers such as hydrogen and hydrocarbons are generated in the fuel chamber 39. The energy carriers generated in the fuel chamber 39 are exhausted to the outside of the stack 10 through the manifold 23.

[0035] When stack 10 is a fuel cell, when fuel gas is flowed through fuel chamber 39 and oxidant gas is flowed through air chamber 41, gas-phase oxygen reacts with electrons at air electrode 36 of cell 33 to generate oxide ions, and the oxide ions that have moved through electrolyte 34 react with fuel gas at fuel electrode 35 to generate electrons. This causes a current to flow through a load (not shown) connected to terminals 14 and 16 (see FIG. 1).

[0036] Distance D2 between the anode 35 and the boundary between the fuel chamber 39 and manifold 22 in upstream section 27 is longer than distance D1 between the anode 35 and the boundary between the fuel chamber 39 and manifold 22 in central section 26. Distance D3 between the anode 35 and the boundary between the fuel chamber 39 and manifold 22 in downstream section 28 is shorter than distance D1. In this embodiment, the anode 35 in central section 26, the anode 35 in upstream section 27, and the anode 35 in downstream section 28 are all equal in size.

[0037] 3 is a cross-sectional view of the laminate 12 taken along line III-III in FIG. 2. The starting point of distance D2 on the manifold 22 side is the edge of the manifold 22 closest to the anode 35, regardless of the slits 40 connecting to the manifold 22. Similarly, the starting points of distances D1 and D3 on the manifold 22 side are the edge of the manifold 22 closest to the anode 35, regardless of the slits 40 connecting to the manifold 22. Distance D4 between the boundary between the fuel chamber 39 and the manifold 23 in the upstream section 27 and the anode 35 is shorter than distance D2. The starting point of distance D4 on the manifold 23 side is also the edge of the manifold 23 closest to the anode 35, regardless of the slits 42 connecting to the manifold 23.

[0038] Returning to FIG. 2 , the following explanation is provided. Because distance D3 is shorter than distance D1, the difference between the distance between the inlet of the manifold 22 (end plate 18 in this embodiment) and the anode 35 in the downstream section 28 and the distance between the inlet of the manifold 22 and the anode 35 in the central section 26 can be reduced. Compared to when distance D3 is equal to distance D1, the difference between the fuel gas concentration at the anode 35 in the downstream section 28 and the fuel gas concentration at the anode 35 in the central section 26 can be reduced. Because the difference between the output of the cells 33 in the downstream section 28 and the output of the cells 33 in the central section 26 can be reduced, it is possible to prevent the cells 33 in the downstream section 28 from continuing to operate with low-concentration fuel gas. Because deterioration of the cells 33 in the downstream section 28 can be reduced, the durability of the stack 10 can be improved.

[0039] When the number of reaction units 11 in the central portion 26 is one, the distance D1 is the distance between the fuel electrode 35 included in that reaction unit 11 and the manifold 22. When the number of reaction units 11 in the central portion 26 is multiple, the distance D1 compared with the distance D3 is the shortest distance among multiple distances between the fuel electrode 35 and the manifold 22.

[0040] When the downstream section 28 includes a plurality of fuel electrodes 35, the distances D3 may all be the same value, or some of the distances D3 may be different. When some of the distances D3 are different, it is preferable that the distances D3 gradually decrease with increasing distance from the central section 26. This is because the distance that the fuel gas supplied to the reaction units 11 in the downstream section 28 flows through the manifold 22 gradually increases with increasing distance from the central section 26.

[0041] When the central portion 26 has a plurality of reaction units 11, the distances D1 may all be the same value, or some of the distances D1 may be different. When some of the distances D1 are different, it is preferable that the distances D1 gradually decrease toward the downstream portion 28. This is because the distance that the fuel gas supplied to the reaction units 11 in the central portion 26 flows through the manifold 22 gradually increases toward the downstream portion 28.

[0042] Furthermore, because distance D2 is longer than distance D1, the difference between the distance between the inlet of manifold 22 and the anode 35 in upstream section 27 and the distance between the inlet of manifold 22 and the anode 35 in central section 26 can be reduced. Compared to when distance D2 is equal to distance D1, the difference between the fuel gas concentration at the anode 35 in central section 26 and the anode 35 in upstream section 27 can be reduced. Because the difference between the output of cells 33 in central section 26 and the output of cells 33 in upstream section 27 can be reduced, it is possible to prevent the output of any particular cell among the cells 33 in central section 26 and the upstream section 27 from becoming excessive. This improves the durability of stack 10.

[0043] When the number of reaction units 11 in the central portion 26 is plural, the distance D1 compared with the distance D2 is the longest distance among the plural distances between the fuel electrode 35 and the manifold 22.

[0044] When the upstream section 27 includes a plurality of fuel electrodes 35, the distances D2 may all be the same value, or some of the distances D2 may be different. When some of the distances D2 are different, it is preferable that the distances D2 gradually increase with increasing distance from the central section 26. This is because the distance that the fuel gas supplied to the reaction units 11 in the upstream section 27 flows through the manifold 22 gradually decreases with increasing distance from the central section 26.

[0045] Furthermore, because the shortest distance among distances D2 is longer than the longest distance among distances D3, the difference between the distance between the inlet of manifold 22 and the anode 35 in downstream section 28 and the distance between the inlet of manifold 22 and the anode 35 in upstream section 27 can be reduced. Compared to when distance D2 is equal to distance D3, the difference between the fuel gas concentration at the anode 35 in downstream section 28 and the fuel gas concentration at the anode 35 in central section 26 can be reduced. Because the difference between the output of cells 33 in downstream section 28 and the output of cells 33 in central section 26 can be reduced, it is possible to prevent cells 33 in downstream section 28 from continuing to operate with low concentration fuel gas. Because deterioration of cells 33 in downstream section 28 can be reduced, the durability of stack 10 can be improved.

[0046] The distance D4 (see FIG. 3) between the boundary between the fuel chamber 39 and the manifold 23 and the fuel electrode 35 in the upstream section 27 is shorter than the distance between the boundary between the fuel chamber 39 and the manifold 23 and the fuel electrode 35 in the central section 26. The distance between the boundary between the fuel chamber 39 and the manifold 23 and the fuel electrode 35 in the downstream section 28 is longer than the distance between the boundary between the fuel chamber 39 and the manifold 23 and the fuel electrode 35 in the central section 26. This is because the fuel electrodes 35 are the same size.

[0047] 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.

[0048] 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.

[0049] 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 35. 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 39 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 41 of the stack 10.

[0050] 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.

[0051] When the stack 10 is used in a hydrogen production device 50, the variations in output of the cells 33 included in the central portion 26, the upstream portion 27, and the downstream portion 28 of the stack 12 can be reduced, thereby improving durability.

[0052] 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.

[0053] In the embodiment, the 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 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 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 manifold 22 from the end plate 17 to the end plate 18.

[0054] In the embodiment, the 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, and the gas flows through the 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 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 manifold 23 from the end plate 18 to the end plate 17 and is exhausted to the outside of the stack 10. The direction of the gas flowing through the manifolds 24 and 25 is also set appropriately.

[0055] In the embodiment, the fuel chambers 39 are connected in parallel to the manifolds 22, 23, but this is not necessarily limited to this. For example, as in the stack disclosed in JP 2017-228481 A, it is of course possible to connect the fuel chambers 39 to the manifolds 22, 23 so that the flow of fuel gas is parallel and serial. In this case, too, the reaction units 11 of the stack 12 are divided into a central portion 26, an upstream portion 27, and a downstream portion 28 according to the flow of fuel gas, and the distance D3 is set to be shorter than the distance D1, and the distance D2 is set to be longer than the distance D1.

[0056] In the embodiment, the case where the distances D1, D2, and D3 are set by changing the position of the fuel electrode 35 without changing the size of the fuel electrode 35 has been described, but this is not necessarily limited to this. It is of course possible to set the distances D1, D2, and D3 by changing the size of the fuel electrode 35. In this case, the position of the fuel electrode 35 may or may not be changed.

[0057] In the embodiment, the case where the shape of the anode frame 29 is constant has been described, but this is not necessarily limited to this. It is of course possible to arrange various anode frames 29 with slits 40 of different lengths. This is because the starting points on the manifold 22 side of the distances D1, D2, and D3 are the edges of the manifold 22 that are closest to the anode 35, regardless of the slits 40 that connect to the manifold 22, and therefore the shape of the anode frame 29 and the lengths of the slits 40 do not affect the distances D1, D2, and D3.

[0058] In the embodiment, the case where the shape of the cells 33 is a rectangle has been described, but this is not necessarily limited to this. The shape of the cells 33 may be a circle or an ellipse, or may be a polygon other than a rectangle, such as a triangle or a pentagon.

[0059] 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.

[0060] In the embodiment, the stack 10 including the solid oxide type cells 33 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]

[0061] 10 stacks 11 Reaction Units 12 Laminate 22 Manifold 26 Central part 27 Upper reaches 28 Downstream 33 cells 34 Electrolytes 35 Fuel electrode 36 Air electrode 39 Fuel chamber 50 Hydrogen production equipment 51 Hot Module 52 Vaporizer 53 Heat exchanger 54 Heater 55 Insulation D1, D2, D3 distance

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 manifold extending in the thickness direction of the stack, connected to the fuel chamber provided in each of the reaction units, and supplying the fuel gas flowing from one side to the other in the thickness direction to the fuel electrode, When the reaction units are divided into a central portion located at the center of the row of the reaction units, an upstream portion of the fuel gas relative to the central portion, and a downstream portion of the fuel gas relative to the central portion, A stack in which the distance between the boundary between the fuel chamber and the manifold and the anode in the downstream portion is shorter than the distance between the boundary between the fuel chamber and the manifold and the anode in the central portion.

2. 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 manifold extending in the thickness direction of the stack, connected to the fuel chamber provided in each of the reaction units, and supplying the fuel gas flowing from one side to the other in the thickness direction to the fuel electrode, When the reaction units are divided into a central portion located at the center of the row of the reaction units, an upstream portion of the fuel gas relative to the central portion, and a downstream portion of the fuel gas relative to the central portion, A stack in which the distance between the boundary between the fuel chamber and the manifold and the anode in the upstream portion is longer than the distance between the boundary between the fuel chamber and the manifold and the anode in the central portion.

3. 2. The stack according to claim 1, wherein the distance between the boundary between the fuel chamber and the manifold and the anode in the upstream portion is longer than the distance between the boundary between the fuel chamber and the manifold and the anode in the central portion.

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

5. The stack of claim 4; 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;

6. A hydrogen production device comprising the hot module according to claim 5.

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