Electrochemical stack, hot module, and hydrogen production apparatus

Abstract

To provide: an electrochemical stack capable of using heat of the stack; a hot module; and a hydrogen production apparatus.SOLUTION: An electrochemical stack includes: a stack to which a plurality of cells including an electrolyte in the shape of a solid oxide for isolating two electrodes are connected in series; a terminal that is disposed in the stack and is electrically connected to the electrodes; a pipe that permits flow of gas supplied to the stack; and a passage disposed in the stack. The passage connects to the cells and the pipe. A part of the terminal is hollow, and the pipe and the passage connect to a hollow part of the terminal.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a solid electrolyte type electrochemical stack, a hot module, and a hydrogen production device.

Background Art

[0002] An electrochemical stack including a cell including an electrolyte that separates two electrodes, the cells being connected in series, and terminals electrically connected to the electrodes is used in an electrolyzer or a fuel cell that produces energy carriers such as hydrogen and hydrocarbons. The prior art disclosed in Patent Document 1 related to a fuel cell applies an oxidant gas discharged from the stack to the terminals in order to reduce the temperature drop of the cells near the terminals.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The prior art has a problem that when the temperature of the oxidant gas applied to the terminals is lower than the temperature of the terminals, the terminals cannot be heated, so the heat of the stack cannot be utilized.

[0005] The present invention has been made to meet this requirement, and an object thereof is to provide an electrochemical stack, a hot module, and a hydrogen production device that can utilize the heat of the stack.

Means for Solving the Problems

[0006] A first aspect for achieving this object is an electrochemical stack, which includes a stack in which a plurality of cells including a solid oxide type electrolyte that isolates two electrodes are connected in series, a terminal disposed on the stack and electrically connected to the electrodes, a pipe through which a gas supplied to the stack flows, and a passage provided in the stack. The passage is connected to the cells and the pipe, the terminal is partially hollow, and the pipe and the passage are connected to the hollow portion of the terminal.

[0007] A second aspect is, in the first aspect, the stack includes flat plate-shaped cells stacked, the terminal includes a first conductor and a second conductor respectively connected to two electrodes isolated by the electrolyte, the passage includes a first part extending along the stacking method of the cells, a plurality of second parts branching from the first part and connected to the cells, a third part extending along the stacking method of the cells, and a plurality of fourth parts branching from the third part and connected to the cells. The third part and the fourth part are not connected to the first part and the second part. The first conductor includes a first cavity connected to the first part and a second cavity branching from the first cavity and connected to the second part. The second conductor includes a third cavity connected to the third part.

[0008] A third aspect is, in the first or second aspect, the stack includes a laminate in which flat plate-shaped cells are stacked, and the thickness of the portion of the terminal that overlaps the laminate in the stacking direction of the cells is thicker than the thickness of the members constituting the laminate.

[0009] A fourth aspect is, in any one of the first to third aspects, the cell has the function of an electrolytic cell.

[0010] A fifth aspect is a hot module, which includes the electrochemical stack in the fourth aspect, a vaporizer that generates steam supplied to the electrochemical stack, a heat exchanger that performs heat exchange with the gas supplied to the electrochemical stack, a heater for heating the electrochemical stack, and a heat insulating material in which the electrochemical stack, the vaporizer, the heat exchanger, and the heater are disposed inside.

[0011] A sixth aspect is a hydrogen production device, which includes the hot module in the fifth aspect.

Advantages of the Invention

[0012] According to the present invention, a part of the terminal connected to the electrode of the cell is hollow, and the tubes through which the gas supplied to the stack flows, and the passages connecting the cell and the tubes are connected to the hollow part of the terminal. The Joule heat generated in the terminal is transmitted to the gas, and the cooling of the cell supplied with the gas can be reduced, so that the heat of the stack can be utilized.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0014] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view of an electrochemical stack 10 in one embodiment. The electrochemical stack 10 includes a solid oxide type stack 11, terminals 14 and 15 disposed on the stack 11, and tubes 25 and 26 for supplying gas to the stack 11. The material of the tubes 25 and 26 is exemplified by stainless steel.

[0015] Stack 11 includes a laminate 13 in which reaction units 12 are stacked in the thickness direction, and end plates 18 and 19 that sandwich the laminate 13 in the thickness direction. Terminal 14 is disposed between the laminate 13 and the end plate 18, and terminal 15 is disposed between the laminate 13 and the end plate 19. Insulators 16 disposed between terminal 14 and end plate 18 and insulators 17 disposed between terminal 15 and end plate 19 electrically insulate between terminals 14 and 15 and end plates 18 and 19. At the periphery of stack 11, bolts 20 that penetrate end plates 18 and 19, insulators 16 and 17, terminals 14 and 15, and laminate 13 in the thickness direction are disposed. Stack 11 is fastened by bolts 20.

[0016] Four spaces that penetrate the periphery of stack 11 in the thickness direction function as a passage 21 for supplying fuel gas from outside stack 11 to a fuel chamber 37 (described later) of reaction unit 12, a passage 22 for discharging gas from the fuel chamber 37, a passage 23 for supplying oxidant gas from outside stack 11 to an air chamber 38 (described later) of reaction unit 12, and a passage 24 for discharging gas from the air chamber 38, respectively.

[0017] FIG. 2 is a cross-sectional view of the electrochemical stack 10 cut along line II-II of FIG. 1 passing through passages 21 and 22. In FIG. 2, the thicknesses of the respective parts are exaggerated (the same applies to FIGS. 3 and 4). The reaction unit 12 includes, in order in the thickness direction, a fuel electrode frame 33, a separator 34, an air electrode frame 35, and a separator 36. Holes (passages 21 - 24) penetrate the fuel electrode frame 33, the separator 34, the air electrode frame 35, and the separator 36. Inside the fuel electrode frame 33, the separator 34, the air electrode frame 35, and the separator 36, cells 27, current collectors 31, and interconnects 32 are disposed.

[0018] Figure 3 is a cross-sectional view of the cell 27. The cell 27 includes a fuel electrode 28, an air electrode 29, and an electrolyte 30 that separates the fuel electrode 28 and the air electrode 29. In this embodiment, a flat cell 27 is described, but it is not limited thereto. The cell 27 may be a metal-supported type (metal-supported flat type) in which electrodes and an electrolyte are supported by a porous body of a metal such as an Fe—Cr system. The cell 27 may be of an electrode-supported type or an electrolyte-supported type.

[0019] The material of the electrolyte 30 is a solid oxide, and examples thereof include a solid solution of one or more selected from stabilized zirconia, ceria-based solid solution, stabilized zirconia and ceria-based solid solution, and alumina. Examples of the stabilizer of stabilized zirconia include CaO, MgO, Y2O3, Sc2O3, and Yb2O3. Examples of the elements dissolved in ceria in the ceria-based solid solution include Gd, Sm, and Y.

[0020] Examples of the material of the fuel electrode 28 include those containing a catalyst containing Ni and zirconia in which Y is dissolved, and those containing a catalyst containing Ni and ceria in which Gd is dissolved. Examples of the catalyst include Ni, Ni-based alloys, and cermets that are composites (sintered bodies) of NiO and an oxide (solid electrolyte).

[0021] The material of the air electrode 29 is a perovskite-type oxide 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 are exemplified.

[0022] Returning to FIG. 2 for description. The current collector 31 electrically connects the terminal 14 or the interconnector 32 adjacent in the thickness direction and the fuel electrode 28 (see FIG. 3) of the cell 27. Examples of the material of the current collector 31 include a porous body made of a metal such as Ni having gas permeability.

[0023] The interconnector 32 electrically connects the current collector 31 adjacent in the thickness direction and the air electrode 29 (see FIG. 3) of the cell 27. As an example of the material of the interconnector 32, stainless steel is cited.

[0024] The fuel electrode frame 33 is disposed between the separator 36 and the separator 34, and is a frame-shaped member surrounding the cell 27 and the current collector 31. As an example of the material of the fuel electrode frame 33, stainless steel is cited.

[0025] The separator 34 is a frame-shaped member, and is hermetically joined to the electrolyte 30 by a brazing material or the like, avoiding the air electrode 29 (see FIG. 3) of the cell 27. As an example of the material of the separator 34, stainless steel is cited.

[0026] The air electrode frame 35 is disposed between the separator 34 and the separator 36, and is a frame-shaped member surrounding the interconnector 32. As an example of the material of the air electrode frame 35, an insulator such as mica is cited.

[0027] The separator 36 is a frame-shaped member, and is hermetically joined to the interconnector 32 by a brazing material or the like. As an example of the material of the separator 36, stainless steel is cited.

[0028] A fuel chamber 37 is provided inside the fuel electrode frame 33, and an air chamber 38 is provided inside the air electrode frame 35. The fuel chamber 37 is connected to the passages 21, 22, and the air chamber 38 is connected to the passages 23, 24 (see FIG. 1). The passage 21 includes a first portion 42 extending along the stacking direction of the cell 27, and a fuel chamber 37 (second portion) branched from the first portion 42 and connected to the cell 27. The separators 34 and 36 isolate the fuel chamber 37 and the air chamber 38 so that the fuel gas in the fuel chamber 37 and the oxidant gas in the air chamber 38 do not mix.

[0029] The partition plate 39 disposed between the terminal 15 and the insulator 17 partitions the inside and outside of the stack 11. The material of the partition plate 39 is exemplified by stainless steel. The laminate 13 is pressed between the terminal 14 and the terminal 15 by the insert 40 disposed between the end connector 32 of the laminate 13 and the partition plate 39.

[0030] When the stack 11 is a fuel cell, the fuel gas is exemplified by hydrogen, carbon monoxide, and hydrocarbons, and the oxidant gas is exemplified by oxygen and air. When the stack 11 is an electrolyzer (the cell 27 is an electrolytic cell), the fuel gas is exemplified by steam, carbon dioxide, and their mixed gases, and the oxidant gas is exemplified by oxygen and air. The stack 11 includes those capable of reversible operation between a fuel cell and an electrolyzer.

[0031] The plurality of cells 27 are electrically connected in series between the terminals 14 and 15 via the current collector 31 and the connector 32. When the stack 11 is a fuel cell, a load (not shown) is connected to the terminals 14 and 15. In a fuel cell, gaseous oxygen reacts with electrons at the air electrode 29 (see FIG. 3) of the cell 27 to generate oxide ions. The oxide ions that have moved through the electrolyte 30 react with the fuel gas at the fuel electrode 28 to generate electrons. As a result, a current flows through the load via the terminals 14 and 15.

[0032] When the stack 11 is an electrolyzer, when the positive electrode of a power source (not shown) is connected to the terminal 15 and the negative electrode of the power source is connected to the terminal 14, a current flows through the terminals 14 and 15, and electrons flow out toward the fuel electrode 28 of the cell 27. The fuel gas that has entered the fuel chamber 37 is reduced at the fuel electrode 28. Since electrons are taken away at the air electrode 29, the oxide ions that have moved to the air electrode 29 through the electrolyte 30 are oxidized at the air electrode 29. As a result, energy carriers such as hydrogen and hydrocarbons are synthesized in the stack 11.

[0033] The operating temperature of the cell 27 is exemplified by 600 - 1000°C. The stack 11 is surrounded by a heat insulating material 41 to ensure the energy efficiency of heating the cell 27 to the operating temperature. The heat insulating material 41 is exemplified by heat resistant fibers such as ceramic wool, refractory ceramic fiber (RCF), bio - soluble fiber (AES), and a heat resistant container formed of heat resistant fibers. Inside the heat insulating material 41, a heater 64 (described later) for heating the cell 27 to the operating temperature is arranged.

[0034] FIG. 4 is a cross - sectional view of the electrochemical stack 10 cut along line IV - IV of FIG. 1 passing through the passages 23, 24 of the stack 11. The passage 23 through which the oxidant gas flows toward the cell 27 includes a third part 43 extending along the stacking direction of the cell 27 and an air chamber 38 (fourth part) branching from the third part 43 and connected to the cell 27. The air chamber 38 is also connected to the passage 24.

[0035] Returning to FIG. 2 for explanation, a pipe 25 for supplying fuel gas to the stack 11 from the outside of the heat insulating material 41 is connected to a terminal 14 (first conductor). The terminal 14 includes an overlapping part 44 overlapping the laminate 13 in the thickness direction and an overhanging part 45 protruding from the overlapping part 44 in a direction intersecting the stacking direction of the laminate 13. The overhanging part 45 includes a hollow part 46 provided with a space 47 inside. In this embodiment, the hollow part 46 extends to the outside of the heat insulating material 41.

[0036] In the overlapping part 44, a first cavity 48 connected to the first part 42 and the space 47 and a second cavity 49 branching from the first cavity 48 and connected to the fuel chamber 37 are provided. The second cavity 49 is also connected to the space 47.

[0037] The pipe 25 is connected to the part of the hollow part 46 outside the heat insulating material 41. An electrically insulating gasket 50 is arranged between the pipe 25 and the hollow part 46, and the pipe 25 is connected to the hollow part 46 with an electrically insulating ceramic screw 51. Thereby, the pipe 25 is electrically insulated from the terminal 14.

[0038] The fuel gas that enters the hollow portion 46 of the terminal 14 from the pipe 25 enters the fuel chamber 37 closest to the end plate 18 through the space 47 and the second cavity 49, and exits the stack 11 and the heat insulating material 41 from the passage 24 through the cell 27 closest to the end plate 18. The remaining fuel gas flowing through the space 47 enters the first part 42 through the first cavity 48, passes through a plurality of fuel chambers 37 branched from the first part 42, and exits the stack 11 and the heat insulating material 41 from the passage 22.

[0039] As shown in FIG. 4, the pipe 26 for supplying the oxidant gas from outside the heat insulating material 41 to the stack 11 is connected to the terminal 15 (the second conductor). The terminal 15 includes an overlapping portion 52 that overlaps the laminate 13 in the thickness direction, and an overhanging portion 53 that protrudes from the overlapping portion 52 in a direction intersecting the stacking direction of the laminate 13. The overhanging portion 53 includes a hollow portion 54 in which a space 55 is provided inside. In the present embodiment, the hollow portion 54 extends to the outside of the heat insulating material 41. A third cavity 56 that connects the third part 43 and the space 55 is provided in the overlapping portion 52.

[0040] The pipe 26 is connected to the portion of the hollow portion 54 outside the heat insulating material 41. An electrically insulating gasket 57 is disposed between the pipe 26 and the hollow portion 54, and the pipe 26 is connected to the hollow portion 54 with an electrically insulating ceramic screw 58. Thereby, the pipe 26 is electrically insulated from the terminal 15.

[0041] The oxidant gas that enters the hollow portion 54 of the terminal 15 from the pipe 26 enters the third part 43 through the space 55 and the third cavity 56, passes through a plurality of air chambers 38 branched from the third part 43, passes through the cell 27, and exits the stack 11 and the heat insulating material 41 from the passage 24.

[0042] When stack 11 is a fuel cell or an electrolyzer, current flows through terminals 14 and 15, so Joule heat is generated at terminals 14 and 15. Since the fuel gas is supplied to stack 11 through the hollow portion 46 of terminal 14, it is supplied to cell 27 after being heated by the Joule heat of terminal 14. By utilizing the heat dissipation of terminal 14 to heat the fuel gas, the cooling of cell 27 can be reduced, thus reducing energy loss. Since the oxidant gas is supplied to stack 11 through the hollow portion 54 of terminal 15, it is supplied to cell 27 after being heated by the Joule heat of terminal 15. By utilizing the heat dissipation of terminal 15 to heat the oxidant gas, the cooling of cell 27 can be reduced, thus reducing energy loss.

[0043] The overhang portions 45 and 53 of terminals 14 and 15 are inside the heat insulating material 41 and protrude outside the laminate 13, so they are heated by the atmosphere around stack 11. Therefore, the overhang portions 45 and 53 are heated by the atmosphere in addition to the Joule heat. Since the heat energy given to the fuel gas and the oxidant gas passing through the spaces 47 and 55 of the hollow portions 46 and 54 provided in the overhang portions 45 and 53 can be increased by the atmosphere, the energy loss can be further reduced.

[0044] Stack 11 is preferably capable of operating as an electrolyzer, that is, cell 27 preferably has the function of an electrolytic cell. This is because the current flowing through terminals 14 and 15 can be controlled by a power source (not shown) connected to terminals 14 and 15, so the heat generation of terminals 14 and 15 due to Joule heat can be ensured.

[0045] Terminal 14 and tube 25 are electrically insulated, and terminal 15 and tube 26 are also electrically insulated, so electric shock when touching tubes 25 and 26 can be prevented. Since heat is directly transferred from the hollow portion 46 to the fuel gas entering terminal 14 from tube 25 and heat is directly transferred from the hollow portion 54 to the oxidant gas entering terminal 15 from tube 26, the heat transfer efficiency can be increased.

[0046] The fuel gas is heated by terminal 14, and the oxidant gas is heated by terminal 15, and they are supplied to the stack 11. Therefore, compared with the case where only one of the fuel gas and the oxidant gas is heated, the heat radiation of terminals 14 and 15 can be effectively utilized.

[0047] Terminal 14 (the first conductor) includes a first cavity 48 connected to the first part 42 and a second cavity 49 branched from the first cavity 48 and connected to the fuel chamber 37 (the second part). Terminal 15 (the second conductor) includes a third cavity 56 connected to the third part 43. Since the cavity structures provided in the overlapping part 44 of terminal 14 and the cavity structure provided in the overlapping part 52 of terminal 15 are different, fuel gas and oxidant gas can be supplied to all the cells 27 arranged in the laminate 13 without waste.

[0048] When comparing the members (cells 27, current collectors 31, interconnects 32, fuel electrode frames 33, separators 34, air electrode frames 35, and separators 36) constituting the laminate 13 with the thicknesses of the overlapping parts 44 and 52 of terminals 14 and 15, the overlapping parts 44 and 52 are thicker. This makes it easier to form the first cavity 48, the second cavity 49, and the third cavity 56 in the overlapping parts 44 and 52 and ensures the strength of the overlapping parts 44 and 52.

[0049] The hydrogen production device 60 and the hot module 61 including the electrochemical stack 10 will be described with reference to FIG. 5. FIG. 5 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.

[0050] The hot module 61 includes an electrochemical stack 10, a vaporizer 62 that generates steam supplied to the stack 11, a heat exchanger 63 that performs heat exchange between the gas supplied to the stack 11 and the gas generated by the stack 11, and a heater 64 that heats the stack 11. For reducing heat dissipation, the stack 11, the vaporizer 62, the heat exchanger 63, and the heater 64 are arranged inside the heat insulating material 41 in the hot module 61. Heat-resistant fibers such as ceramic wool, RCF, and AES fill the gaps between the stack 11, the vaporizer 62, the heat exchanger 63, and the heater 64.

[0051] The vaporizer 62 includes a heat exchanger that exchanges heat with the high-temperature gas containing oxygen generated by the stack 11, and heats water to produce steam. The steam generated by the vaporizer 62 contains hydrogen that reduces the oxidation of the catalyst contained in the fuel electrode 28 (see FIG. 3). The steam containing hydrogen is heat-exchanged by the heat exchanger 63 with the hydrogen and oxygen generated by the stack 11, and then heated to the operating temperature of the stack 11 by the heater 64 and supplied to the fuel chamber 37 of the stack 11. Air is heat-exchanged by the heat exchanger 63 with the hydrogen and oxygen generated by the stack 11, and then heated to the operating temperature of the stack 11 by the heater 64 and supplied to the air chamber 38 of the stack 11. The condenser 65 is a device that cools hydrogen gas, and the liquefied water is supplied to the vaporizer 62 as raw material water.

[0052] Although the present invention has been described based on the embodiments above, it is easily inferred that the present invention is not limited to the above embodiments at all, and various improvements and modifications can be made without departing from the spirit of the present invention.

[0053] In the embodiment, the electrochemical stack 10 with the flat plate-shaped cells 27 connected is described, but it is not necessarily limited to this. It is naturally possible to adopt other cell designs than the flat plate shape for the electrochemical stack. Examples of other cell designs include metal-supported flat plate shape, cylindrical flat plate shape, cylindrical horizontal stripe shape, and cylindrical vertical stripe shape.

[0054] In the embodiment, the case where both the fuel gas and the oxidant gas are heated at the terminals 14 and 15 has been described, but it is not necessarily limited to this. It is of course possible to heat either the fuel gas or the oxidant gas at the terminal 14 or the terminal 15.

[0055] In the embodiment, the case where the terminal 14 is the first conductor including the first cavity 48 and the second cavity 49, the first conductor is used as the passage for the fuel gas, the terminal 15 is the second conductor including the third cavity 56, and the second conductor is used as the passage for the oxidant gas has been described, but it is not necessarily limited to this. For example, if a laminate with the front and back of the reaction unit 12 swapped is used and the air chamber 38 is connected to the second cavity 49 of the terminal 14, the first conductor can be used as the passage for the oxidant gas and the second conductor can be used as the passage for the fuel gas. In this case, the air chamber 38 becomes the second part.

[0056] Similarly, it is of course possible to use the terminal 15 as the first conductor including the first cavity and the second cavity, and the terminal 14 as the second conductor including the third cavity. In this case, the fuel chamber 37 may be connected to the second cavity of the terminal 15, or the air chamber 38 may be connected to the second cavity.

[0057] In the embodiment, the case where a part of the hollow portions 46 and 54 is arranged outside the heat insulating material 41 has been described, but it is not necessarily limited to this. It is of course possible to arrange the entire hollow portions 46 and 54 inside the heat insulating material 41 and connect the pipes 25 and 26 to the hollow portions 46 and 54 respectively inside the heat insulating material 41.

[0058] In the embodiment, the case where gaskets 50 and 57 are arranged between the pipes 25 and 26 and the hollow portions 46 and 54 respectively, and the pipes 25 and 26 are joined to the hollow portions 46 and 54 using screws 51 and 58 has been described, but it is not necessarily limited to this. It is of course possible to drill a hole in the hollow portions 46 and 54 that is larger than the pipes 25 and 26 without flanges, fit the hole and the pipes with a clearance fit, and seal the gap between the hole and the pipes with an inorganic adhesive having heat resistance and electrical insulation to join the hollow portions 46 and 54 and the pipes.

[0059] Although the description is omitted in the embodiment, it is of course possible to provide fins (protrusions) protruding toward the spaces 47 and 55 in the hollow portions 46 and 54, respectively. When fins are provided in the hollow portions 46 and 54, the heat transfer area is increased, so that the heat transfer efficiency can be improved.

Explanation of Signs

[0060] 10 Electrochemical stack 11 Stack 13 Laminate 14 Terminal (first conductor) 15 Terminal (second conductor) 21, 23 Passage 25, 26 Pipe 27 Cell 28 Fuel electrode (electrode) 29 Air electrode (electrode) 30 Electrolyte 37 Fuel chamber (second part) 38 Air chamber (fourth part) 41 Heat insulating material 42 First part 43 Third part 46, 54 Hollow portion 48 First cavity 49 Second cavity 56 Third cavity 60 Hydrogen production device 61 Hot module 62 Vaporizer 63 Heat exchanger 64 Heater

Claims

1. A stack in which cells each including a solid oxide electrolyte separating two electrodes are connected in series, terminals disposed in the stack and electrically connected to the electrodes, a tube through which a gas supplied to the stack flows, and a passage provided in the stack, and the passage is an electrochemical stack connected to the cell and the tube, a part of the terminals is hollow, and the tube and the passage are an electrochemical stack connected to the hollow part of the terminals.

2. the stack includes the flat cells stacked, the terminals include a first conductor and a second conductor respectively connected to the two electrodes separated by the electrolyte, the passage includes a first part extending along the stacking method of the cells, a plurality of second parts branching from the first part and connected to the cells, a third part extending along the stacking method of the cells, and a plurality of fourth parts branching from the third part and connected to the cells, the third part and the fourth part are not connected to the first part and the second part, the first conductor includes a first cavity connected to the first part, and a second cavity branching from the first cavity and connected to the second part, the second conductor includes a third cavity connected to the third part. The electrochemical stack according to Claim 1.

3. the stack includes a laminate in which the flat cells are stacked, the thickness of a part of the terminals overlapping the laminate in the stacking direction of the cells is thicker than the thickness of the members constituting the laminate. The electrochemical stack according to Claim 1.

4. the cell has the function of an electrolytic cell. The electrochemical stack according to any one of Claims 1 to 3.

5. The electrochemical stack according to Claim 4, a vaporizer that generates steam supplied to the electrochemical stack, a heat exchanger that performs heat exchange with the gas supplied to the electrochemical stack, a heater for heating the electrochemical stack, and a heat insulating material in which the electrochemical stack, the vaporizer, the heat exchanger, and the heater are disposed inside. A hot module.

6. A hydrogen production apparatus including the hot module according to Claim 5.

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