Cell stack, hot module, and hydrogen production apparatus

Abstract

To provide a cell stack capable of improving cell durability, a hot module, and a hydrogen production apparatus.SOLUTION: A cell stack comprises: a laminate in which a plurality of cells containing an electrolyte for isolating a fuel electrode and an air electrode are laminated; terminal plates arranged outside both ends of the laminate in the laminating direction and electrically connected to the cells; and a first supply path and a first discharge path provided side by side with the cells and extending in the laminating direction. A fuel gas supplied to the fuel electrode flows in the first supply path, and a gas containing a gas after the reaction of the fuel gas in the fuel electrode flows in the first discharge path. Each of the terminal plates includes a terminal. When the cell stack is viewed from the laminating direction, a terminal of at least one terminal plate is present in an area including the first discharge path, of the two areas divided by a vertical bisector of a line segment connecting the center of the first supply path and the center of the first discharge path.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cell stack in which a plurality of cells, each containing an electrolyte that separates a fuel electrode from a cathode, are stacked, a hot module including the cell stack, and a hydrogen production device. [Background technology]

[0002] Patent Document 1 discloses a prior art cell stack including a laminate of multiple cells, each containing an electrolyte that separates an anode and an cathode, and a terminal plate electrically connected to the cells. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-73494 Summary of the Invention [Problem to be solved by the invention]

[0004] The prior art calls for improved cell durability.

[0005] The present invention has been made to meet this demand, and has an object to provide a cell 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 for achieving this object is a cell stack including a laminate in which a plurality of cells containing an electrolyte that separates an anode and an cathode are laminated, terminal plates disposed on the outer sides of both ends of the laminate in the stacking direction and electrically connected to the cells, and a first supply path, a first exhaust path, a second supply path, and a second exhaust path that are arranged in parallel with the cells and extend in the stacking direction. A fuel gas to be supplied to the anode flows through the first supply path, and a gas containing a gas obtained after the fuel gas reacts at the anode flows through the first exhaust path. An oxidant gas to be supplied to the cathode flows through the second supply path, and a gas containing a gas obtained after the oxidant gas reacts at the cathode flows through the second exhaust path. The terminal plates each include a terminal. When the cell stack is viewed from the stacking direction, at least one terminal of the terminal plate is present in an area including the first exhaust path out of two areas divided by a perpendicular bisector of a line segment connecting the center of the first supply path and the center of the first exhaust path. The distance between the terminal and the first exhaust path is less than the distance between the terminal and the first supply path, and the distance between the terminal and the second exhaust path is less than the distance between the terminal and the second supply path.

[0007] In the second embodiment, the terminals of the two terminal plates in the first embodiment are present in an area including the first discharge path.

[0008] In a third aspect, in the first or second aspect, the terminal is disposed between the first discharge path and the second discharge path.

[0009] A fourth aspect is the method according to any one of the first to third aspects, wherein the fuel gas contains water vapor.

[0010] The hot module in the fifth aspect comprises a cell stack described in any one of the first to fourth aspects, a vaporizer that generates water vapor to be supplied to the cell stack, a heat exchanger that exchanges heat with the gas supplied to the cell stack, a heater for heating the cell stack, and insulation in which the cell stack, the vaporizer, the heat exchanger and the heater are disposed.

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

[0012] According to the present invention, when the cell stack is viewed from the stacking direction, the two regions are divided by the perpendicular bisector of the line segment connecting the center of the first fuel gas supply path and the center of the first exhaust path, and the region in which the terminal of the terminal plate is present has a higher temperature than the region in which the terminal is not present. The higher the temperature, the higher the cell performance, but since fuel-rich gas is supplied to the cell from the first supply path in the low-temperature region, the reaction in the cell can be ensured. Since the fuel-poor gas reacts in the high-temperature region, the variation in current density in the cell plane is reduced, and the non-uniformity of the reaction in the cell plane is reduced. Therefore, the durability of the cell can be improved. [Brief description of the drawings]

[0013] [Figure 1] FIG. 2 is an exploded assembly view of a cell stack in one embodiment. [Diagram 2] FIG. 2 is a cross-sectional view of the reaction unit taken along line II-II in FIG. [Diagram 3] 4 is a plan view of the terminal plate as viewed from the stacking direction of the laminate. FIG. [Figure 4] FIG. 1 is a block diagram of a hydrogen production device. [Diagram 5] FIG. 13 is a block diagram of another hot module. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Fig. 1 is an exploded view of a cell stack 10 in one embodiment. The cell stack 10 may be, for example, a polymer electrolyte fuel cell or a solid oxide fuel cell, or a solid oxide hydrogen production device. The hydrogen production device may be, for example, one including a steam electrolysis cell (SOEC).

[0015] The cell stack 10 includes a stack 12 in which a plurality of reaction units 11 are stacked. The cell stack 10 includes, in order from the outside of one end of the stack 12 in the stacking direction, a terminal plate 13, an insulating plate 15, and an end plate 16, and includes, in order from the outside of the other end of the stack 12 in the stacking direction, a terminal plate 17, an insulating plate 19, and an end plate 20. The terminal plates 13 and 17 include terminals 14 and 18, respectively, for connection to an electric circuit (not shown).

[0016] A plurality of holes 21 penetrating in the stacking direction of the laminate 12 are provided around the peripheries of the laminate 12, the terminal plates 13 and 17, the insulating plates 15 and 19, and the end plates 16 and 20. The laminate 12, the terminal plates 13 and 17, the insulating plates 15 and 19, and the end plates 16 and 20 are fastened together by members (not shown) such as bolts placed in the holes 21. Four holes 22-25 penetrating in the stacking direction of the laminate 12 are provided around the peripheries of the laminate 12, the terminal plate 13, the insulating plate 15, and the end plate 16.

[0017] The holes 22 are connected in the stacking direction and form a first supply path 30 (described later) that supplies fuel gas to the reaction units 11. The holes 23 are connected in the stacking direction and form a first exhaust path 31 (described later) through which gas containing gas remaining after the fuel gas reacts in the reaction units 11 flows. The holes 24 are connected in the stacking direction and form a second supply path 45 (described later) that supplies oxidant gas to the reaction units 11. The holes 25 are connected in the stacking direction and form a second exhaust path 46 (described later) through which gas containing gas remaining after the reaction in the reaction units 11 flows.

[0018] In a fuel cell, examples of the fuel gas include hydrogen, carbon monoxide, and hydrocarbon, and examples of the oxidant gas include oxygen and air. In a hydrogen production device, examples of the fuel gas include gas containing water vapor and gas containing water vapor and carbon dioxide, and examples of the oxidant gas include oxygen. A hydrogen production device that uses a gas containing water vapor and carbon dioxide as a raw material corresponds to a part of a co-electrolysis system that converts the gas containing water vapor and carbon dioxide into a gas containing hydrogen and carbon monoxide by electrolysis.

[0019] Figure 2 is a cross-sectional view of the reaction unit 11 taken along line II-II in Figure 1. Figure 2 is an exploded view in which the components constituting one reaction unit 11 are separated in the thickness direction. In this embodiment, the reaction unit 11 of a solid oxide cell stack 10 will be described. In Figure 2, the thickness of each part is exaggerated.

[0020] The reaction unit 11 includes, in order in the thickness direction, an interconnector 26, an anode frame 27, a separator-fitted cell 28, and an air electrode frame 29. The separator-fitted cell 28 includes a cell 32 and a separator 38 arranged in the cell 32. The holes 22 provided in the interconnector 26, the anode frame 27, the separator 38, and the air electrode frame 29 are connected in the stacking direction to form a first supply path 30, and the holes 23 connected in the stacking direction to form a first discharge path 31.

[0021] The cell 32 includes, in this order, an anode 33, an electrolyte 36, and an air cathode 37. The anode 33 includes a support 34 and a functional layer 35. The support 34 is a flat porous body having a higher gas permeability than the porosity of the functional layer 35. The support 34 mainly functions to support the functional layer 35. The material constituting the support 34 may be the same as the material constituting the functional layer 35, or may be a different material from the material constituting the functional layer 35. When the material constituting the support 34 is different from the material constituting the functional layer 35, the material of the support 34 is, for example, stabilized zirconia.

[0022] In a fuel cell, the functional layer 35 has the function of reacting oxide ions supplied from the electrolyte 36 with the fuel gas to generate electrons, and in steam electrolysis, it has the function of electrolyzing water vapor when an electric current is passed through it, converting it into hydrogen and oxide ions.

[0023] The functional layer 35 includes a catalyst containing Ni and zirconia with Y dissolved therein. Examples of the catalyst include Ni, Ni-based alloys, and cermets that are composites (sintered bodies) of NiO and oxides (electrolytes). In the cermets, Ni is produced by hydrogen reduction of NiO. Examples of the oxides (electrolytes) contained in the cermets include zirconia with Y dissolved therein. The functional layer 35 may also include a catalyst containing Ni and ceria with Gd dissolved therein.

[0024] The electrolyte 36 is a plate-like member that exhibits oxide ion conductivity under the operating conditions of the cell 32. Examples of the electrolyte 36 include stabilized zirconia, a ceria-based solid solution, and a solid solution of alumina and one or more selected from stabilized zirconia and a ceria-based solid solution.

[0025] The air electrode 37 is disposed in the center of the electrolyte 36. In a fuel cell, the air electrode 37 is the site where the gas phase oxidant (oxygen) reacts with electrons to become oxide ions, and in steam electrolysis, it is the site where the oxide ions release electrons to become oxygen. The material of the air electrode 37 is a perovskite oxide, La 1-X Sr X MnO 3-δ ,La 1-X Sr X Chief of Staff 3-δ ,La 1-X Sr X Co 1-Y Fe Y O 3-δ ,Pr 1-X Sr X MnO 3-δ Examples include:

[0026] The separator 38 is a frame-shaped member disposed around the air electrode 37. The material of the separator 38 is, for example, stainless steel. The separator 38 is airtightly joined to the electrolyte 36 by brazing material or the like, avoiding the air electrode 37.

[0027] The interconnectors 26 are conductive plate-like members arranged on both sides in the thickness direction of the cell 32. The interconnectors 26 electrically connect the reaction units 11 adjacent to each other in the stacking direction. An example of the material of the interconnectors 26 is stainless steel.

[0028] The fuel electrode frame 27 is a frame-shaped member disposed between the interconnector 26 and the separator 38. The material of the fuel electrode frame 27 is, for example, stainless steel. The fuel electrode frame 27 surrounds the cells 32 and a current collector 39 provided in the center of the interconnector 26.

[0029] The current collector 39 electrically connects the anode 33 and the interconnector 26. An example of the material of the current collector 39 is a porous body made of a gas permeable metal such as Ni. A fuel chamber 40 surrounded by the interconnector 26, the anode frame 27, and a separator 38 is provided inside the anode frame 27. A groove 41 provided in the anode frame 27 connects the fuel chamber 40 and the hole 22 (first supply path 30). A groove 42 provided in the anode frame 27 connects the fuel chamber 40 and the hole 23 (first discharge path 31).

[0030] The air electrode frame 29 is a frame-shaped member disposed between the interconnector 26 and the separator 38. The material of the air electrode frame 29 is, for example, an insulator such as mica. The air electrode frame 29 surrounds a current collector 43 provided in the center of the interconnector 26. The current collector 43 electrically connects the air electrode 37 and the interconnector 26. In this embodiment, the current collector 43 is formed integrally with the interconnector 26, but this is not limited to this. It is of course possible for the current collector 43 to be a member separate from the interconnector 26.

[0031] An air chamber 44 is provided inside the air electrode frame 29 and is surrounded by the interconnector 26, the air electrode frame 29, and a separator 38. The separator 38 separates the fuel chamber 40 from the air chamber 44, preventing the fuel gas in the fuel chamber 40 and the oxidizer gas in the air chamber 44 from mixing.

[0032] Returning to Fig. 1, the cell stack 10 has a plurality of reaction units 11 connected in series between terminal plates 13 and 17. The terminal plates 13 and 17 are plate-shaped members made of a conductive material such as stainless steel, and terminals 14 and 18 are connected to the terminals 14 and 18, respectively. The terminals 14 and 18 protrude outward from the stack 12.

[0033] The insulating plates 15 and 19 are plate-shaped members made of an insulator. The insulating plate 15 provides electrical insulation between the terminal plate 13 and the end plate 16, and the insulating plate 19 provides electrical insulation between the terminal plate 17 and the end plate 20.

[0034] 3 is a plan view of the terminal plate 13 when the cell stack 10 (see FIG. 1) is viewed from the stacking direction of the laminate 12. In FIG. 3, the cells 32 overlapping the terminal plate 13 are shown by dashed lines. Holes 21-25 are provided between the edge of the terminal plate 13 and the cells 32. The fuel gas supplied to the cell stack 10 from the hole 22 (first supply path 30) enters the fuel chamber 40 from a groove 41 provided in the fuel electrode frame 27 (see FIG. 2) of each reaction unit 11 and reacts with the fuel electrode 33. The gas containing the gas generated after the reaction of the fuel gas at the fuel electrode 33 enters the hole 23 (first exhaust path 31) from the fuel chamber 40 through the groove 42 provided in the fuel electrode frame 27 of each reaction unit 11, and flows out of the cell stack 10 through the first exhaust path 31.

[0035] The oxidant gas supplied to the cell stack 10 from the hole 24 (second supply path 45) enters the air chamber 44 through a groove (not shown) provided in the air electrode frame 29 (see FIG. 2) of each reaction unit 11. The gas containing oxygen produced in the air electrode 37 passes through a groove (not shown) provided in the air electrode frame 29 of each reaction unit 11, enters the hole 25 (second exhaust path 46) from the air chamber 44, and flows through the second exhaust path 46 to the outside of the cell stack 10.

[0036] When the cell stack 10 is a fuel cell, a load (not shown) is connected to the terminals 14, 18 of the terminal plates 13, 17. The fuel gas supplied to the fuel chamber 40 reacts with oxide ions supplied from the electrolyte 36 at the fuel electrode 33 to generate electrons, and a current flows through the stack 12, generating heat. Of the two areas 49, 50 divided by a perpendicular bisector 48 of a line segment 47 connecting the center of the first fuel gas supply path 30 and the center of the first exhaust path 31, the area 49 where the terminal 14 of the terminal plate 13 is present has a higher temperature than the area 50.

[0037] The width of terminal 14 (the dimension in the vertical direction in FIG. 3) is half or less the width of terminal plate 13. Compared to when the width of terminal 14 is approximately the same as the width of terminal plate 13, the resistance of terminal 14 can be more than doubled, so the Joule heat of terminal 14 can be doubled. This increases the heating effect of area 49 by terminal 14.

[0038] The higher the temperature, the higher the performance of the cell 32; however, since fuel-rich gas is supplied to the cell 32 from the first supply path 30 present in the area 50, which has a lower temperature than the area 49, the generation of electrons in the area 50 of the anode 33 can be ensured. The fuel-poor gas reacts in the area 49, which has a higher temperature and the performance of the cell 32 is higher, and electrons are generated. This reduces the variation in current density within the surface of the cell 32, and reduces the non-uniformity of the reaction within the surface of the cell 32. Since it is possible to prevent the occurrence of parts in the cell 32 through which an excessive current flows, the durability of the cell 32 can be improved.

[0039] When the cell stack 10 is for steam electrolysis, a power source (not shown) is connected to the terminals 14, 18 of the terminal plates 13, 17, and the fuel electrode 33 converts water vapor into hydrogen and oxide ions when electricity is applied. The heat generated by the cell 32 causes the temperature of the area 49 in which the terminal 14 of the terminal plate 13 is present to be higher than that of the area 50. The higher the temperature, the higher the performance of the cell 32. However, since water vapor is supplied to the cell 32 from the first supply path 30 in the area 50, which is lower in temperature than the area 49, the water vapor electrolysis in the area 50 of the cell 32 can be ensured. Even with gas with little water vapor (fuel-poor gas), electrolysis is performed in the area 49, which is high in temperature and where the performance of the cell 32 is high, and the variation in the current density in the plane of the cell 32 is reduced. Since the non-uniformity of the reaction in the plane of the cell 32 is reduced, the durability of the cell 32 can be improved.

[0040] Since the terminals 14, 18 of the two terminal plates 13, 17 are present in the area 49 including the first discharge path 31, the variation in current density within the surface of the cell 32 can be reduced compared to a case in which the terminals 14, 18 of either one of the terminal plates 13, 17 are present in the area 49 including the first discharge path 31. Therefore, the durability of the cell 32 can be further improved.

[0041] In this embodiment, the second supply path 45 for the gas supplied to the air electrode 37 is located in the area 50, and the second discharge path 46 for the gas discharged from the air electrode 37 is located in the area 49. Since the second supply path 45 is located in the area 50, which has a lower temperature than the area 49, when the cell stack 10 is a fuel cell, it is possible to prevent the temperature difference between the area 49 and the area 50 from increasing due to the gas supplied to the air electrode 37. This makes it possible to further reduce the variation in current density within the plane of the cell 32.

[0042] In addition, the distance between the terminal 14 and the first exhaust path 31 is shorter than the distance between the terminal 14 and the first supply path 30, and the distance between the terminal 14 and the second exhaust path 46 is shorter than the distance between the terminal 14 and the second supply path 45. Since the first supply path 30 and the second supply path 45 are located far from the terminal 14, it is possible to prevent the temperature difference between the zone 49 and the zone 50 from increasing due to the fuel gas supplied from the first supply path 30 to the fuel electrode 33 and the oxidant gas supplied from the second supply path 45 to the air electrode 37. This makes it possible to further reduce the variation in current density within the surface of the cell 32.

[0043] A first exhaust path 31 and a second exhaust path 46 are provided on both sides of the range of the terminal 14 projected toward the cell 32. When the cell 32 is a fuel cell, an exothermic reaction occurs, and when electrolysis occurs in the cell 32, an endothermic reaction occurs. Since the terminal 14 is disposed between the first exhaust path 31 and the second exhaust path 46, the Joule heat of the terminal 14 is transferred to the surroundings of the first exhaust path 31 and the second exhaust path 46, and the area 49 can be heated both during the exothermic reaction and during the endothermic reaction.

[0044] A hydrogen production device 60 including the cell stack 10 and a hot module 61 will be described with reference to Fig. 4. Fig. 4 is a block diagram of the hydrogen production device 60. The hydrogen production device 60 is a device that produces hydrogen from water and includes a hot module 61.

[0045] The hot module 61 includes a cell stack 10, a vaporizer 62 that generates water vapor to be supplied to the cell stack 10, a heat exchanger 63 that exchanges heat between the gas supplied to the cell stack 10 and the gas generated by the cell stack 10, and a heater 64 that heats the cell stack 10. In the hot module 61, the cell stack 10, the vaporizer 62, the heat exchanger 63, and the heater 64 are disposed inside a thermal insulation material 65 to reduce heat radiation.

[0046] The vaporizer 62 includes a heat exchanger that exchanges heat with high-temperature gas containing oxygen generated by the cell stack 10, and heats water to produce water vapor. The water vapor generated by the vaporizer 62 contains hydrogen that reduces oxidation of the catalyst contained in the anode 33. The hydrogen-containing water vapor exchanges heat with hydrogen and oxygen generated by the cell stack 10 in the heat exchanger 63, is heated to the operating temperature of the cell stack 10 by the heater 64, and is supplied to the fuel chamber 40 of the cell stack 10. The air exchanges heat with hydrogen and oxygen generated by the cell stack 10 in the heat exchanger 63, is heated to the operating temperature of the cell stack 10 by the heater 64, and is supplied to the air chamber 44 of the cell stack 10.

[0047] Examples of the heat insulating material 65 include heat resistant fibers such as ceramic wool, refractory ceramic fiber (RCF), and biosoluble fiber (AES), and a heat resistant container formed from the heat resistant fibers. The heat resistant fibers fill the gaps between the cell stack 10, the vaporizer 62, the heat exchanger 63, and the heater 64. The condenser 66 is a device that cools the hydrogen gas, and liquefied water is supplied to the vaporizer 62 as raw water.

[0048] A hot module 70 of a fuel cell including a cell stack 10 will be described with reference to Fig. 5. Fig. 5 is a block diagram of the hot module 70. The hot module 70 includes the cell stack 10, a vaporizer 71 that processes fuel gas, a reformer 72 and a heat exchanger 73 that exchange heat with the gas, and a combustor 74. The fuel gas containing hydrocarbons is supplied to the hot module 70 after sulfur content is removed by a desulfurizer 76. The desulfurizer 76 is, for example, a hydrodesulfurization type.

[0049] In order to reduce heat radiation, the hot module 70 has the cell stack 10, vaporizer 71, reformer 72, heat exchanger 73, and combustor 74 disposed inside a thermal insulation material 75. The thermal insulation material 75 is similar to the thermal insulation material 65 of the hot module 61 (see FIG. 4), and therefore a description thereof will be omitted.

[0050] The combustor 74 (heater) combusts the off-gas discharged from the cell stack 10. The vaporizer 71 evaporates water using the heat of the combustion gas obtained in the combustor 74 to generate water vapor. The water vapor generated by the vaporizer 71 is supplied to the reformer 72 together with the desulfurized fuel gas. A portion of the off-gas discharged from the fuel chamber 40 of the cell stack 10 is also mixed with the fuel gas and water vapor, and supplied to the reformer 72.

[0051] The reformer 72 (heat exchanger) contains a steam reforming catalyst. The reformer 72 heats a gas containing fuel gas by heat exchange with the combustion gas of the combustor 74, and reforms the fuel gas in the presence of the catalyst and supplies it to the fuel chamber 40 of the cell stack 10.

[0052] The heat exchanger 73 heats the air supplied to the air chamber 44 of the cell stack 10 by exchanging heat with the combustion gas in the combustor 74. Since the temperature difference between the air and the fuel gas supplied to the cell stack 10 is reduced, the power generation efficiency of the cell stack 10 is improved. The combustion gas that has exchanged heat with the air in the heat exchanger 73 is discharged outside the system.

[0053] The present invention has been described above based on an embodiment, but the present invention is in no way limited to the above embodiment, and it can be easily inferred that various improvements and modifications are possible within the scope of the present invention without departing from the spirit of the present invention.

[0054] In the embodiment, the shape of the cells 32 and the terminal plates 13, 17 as viewed in the stacking direction is rectangular, but this is not necessarily limited to this. The shape of the cells 32 and the terminal plates 13, 17 can be set to any shape, such as a circle, an ellipse, or a polygon other than a rectangle.

[0055] In the embodiment, the fuel electrode-supported cell 32 has been described, but the present invention is not limited to this. It is of course possible to use an electrolyte-supported or metal-supported cell 32.

[0056] In the embodiment, a solid oxide cell stack 10 has been described, but the present invention is not necessarily limited to this. It is of course possible to provide a passage for flowing cooling water around the cells 32 in addition to the first supply path 30 and the first discharge path 31, etc., to make the cell stack 10 a solid polymer cell stack.

[0057] In the embodiment, the case where the portions of the terminal plates 13, 17 that overlap the cells 32 are joined to the terminals 14, 18 has been described, but this is not necessarily limited to this. It is of course possible to mold the terminal plates 13, 17 and the terminals 14, 18 integrally.

[0058] In the embodiment, the hydrogen production device 60 including the hot module 61 using water (steam) as a raw material has been described, but the present invention is not necessarily limited to this. It is of course possible for the hot module to be part of a hydrogen production device that simultaneously electrolyzes water (steam) and carbon dioxide. [Explanation of symbols]

[0059] 10 Cell stack 12 Laminate 13,17 Terminal plate 14,18 Terminal 30 First Supply Channel 31 First Discharge Channel 32 Cells 33 Fuel electrode 36 Electrolytes 37 Air electrode 45 Second Supply Route 46 Second Discharge Channel 47 Line Segments 48 Perpendicular bisector 49,50 area 60 Hydrogen production equipment 61,70 Hot Module 62,71 Carburetor 63,72 Reformer (heat exchanger) 64 Heater 65,75 Insulation 73 Heat exchanger 74 Combustor (heater)

Claims

1. a stack of a plurality of cells each including an electrolyte that separates an anode from an cathode; terminal plates arranged on the outer sides of both ends of the stack in the stacking direction and electrically connected to the cells; a first supply path, a first discharge path, a second supply path, and a second discharge path that are arranged alongside the cells and extend in the stacking direction; The first supply path carries a fuel gas to be supplied to the fuel electrode, the first exhaust passage is for flowing a gas containing a gas remaining after the reaction of the fuel gas at the fuel electrode; the second supply path carries an oxidant gas to be supplied to the air electrode; the second exhaust passage is for a gas containing a gas remaining after the reaction of the oxidant gas at the air electrode to flow therethrough, The terminal plate is a cell stack including a terminal, A cell stack in which, when the cell stack is viewed from the stacking direction, the terminal of at least one of the terminal plates is present in a region including the first discharge path, out of two regions separated by a perpendicular bisector of a line segment connecting the center of the first supply path and the center of the first discharge path, and the distance between the terminal and the first discharge path is shorter than the distance between the terminal and the first supply path, and the distance between the terminal and the second discharge path is shorter than the distance between the terminal and the second supply path.

2. The cell stack according to claim 1 , wherein the terminals of the two terminal plates are present in the area including the first discharge path.

3. The cell stack according to claim 1 , wherein the terminal is disposed between the first exhaust path and the second exhaust path.

4. The cell stack according to claim 1 , wherein the fuel gas contains water vapor.

5. The cell stack according to claim 1 or 2; a vaporizer for generating water vapor to be supplied to the cell stack; a heat exchanger for exchanging heat with the gas supplied to the cell stack; a heater for heating the cell stack; a heat insulating material in which the cell stack, the vaporizer, the heat exchanger and the heater are disposed.

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

Images