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 in the shape of a solid oxide to which a plurality of cells including an electrolyte for isolating two electrodes are connected in series; a terminal that is disposed in the stack and is electrically connected to the electrodes; and a pipe that permits flow of gas supplied to the cells. The terminal has a part extending outside of the stack, and the terminal includes a transfer part that transfers heat of the terminal to the gas flowing through the pipe. The transfer part and the pipe are electrically isolated.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 and having a plurality of the cells 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 is a solid oxide type stack in which a plurality of cells including an electrolyte that separates two electrodes are connected in series, terminals arranged in the stack and electrically connected to the electrodes, and a tube through which the gas supplied to the cell flows. The terminal has a portion extending outside the stack, and the terminal includes a transmission portion that transfers the heat of the terminal to the gas flowing through the tube, and the transmission portion and the tube are electrically insulated.

[0007] A second aspect is that, in the first aspect, the transmission portion is provided on the outer surface of the portion of the terminal extending outside the stack, and heat is transferred from the transmission portion to the outer surface of the tube.

[0008] A third aspect is that, in the first aspect, a part of the terminal is hollow, the tube is connected to the hollow portion of the terminal, the transmission portion is provided inside the terminal, and the gas is supplied to the cell through the transmission portion.

[0009] A fourth aspect is that, 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 exchanges heat 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 arranged 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, in addition to Joule heat being generated at the terminals, when the stack is heated from the surroundings, the portion of the terminals that extends outside the stack is heated. Since the transmission portion of the terminals is electrically insulated from the pipes through which the gas supplied to the cells flows, electric shock can be prevented when touching the pipes. The transmission portion transfers the heat of the terminals to the gas supplied to the cells, and can reduce the cooling of the cells to which the gas is supplied, 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 the first embodiment. The electrochemical stack 10 includes a solid oxide type stack 11, terminals 13 and 14 disposed on the stack 11, and pipes 24 and 25 for supplying gas to the stack 11.

[0015] Stack 11 includes a plurality of reaction units 12 stacked in the thickness direction, and end plates 17 and 18 sandwiching the reaction units 12 in the thickness direction. Terminal 13 is disposed between the reaction unit 12 and the end plate 17, and terminal 14 is disposed between the reaction unit 12 and the end plate 18. Insulators 15 disposed between the terminal 13 and the end plate 17 and insulators 16 disposed between the terminal 14 and the end plate 18 electrically insulate between the terminals 13 and 14 and the end plates 17 and 18. Bolts 19 passing through the end plates 17 and 18, insulators 15 and 16, terminals 13 and 14, and reaction units 12 in the thickness direction are disposed on the periphery of the stack 11. The stack 11 is fastened by the bolts 19.

[0016] Four spaces passing through the periphery of the stack 11 in the thickness direction function as a passage 21 for supplying fuel gas from outside the stack 11 to a fuel chamber 36 (described later) of the reaction unit 12, a passage 20 for discharging gas from the fuel chamber 36, a passage 22 for supplying oxidant gas from outside the stack 11 to an air chamber 37 (described later) of the reaction unit 12, and a passage 23 for discharging gas from the air chamber 37, respectively.

[0017] FIG. 2 is a cross-sectional view of the electrochemical stack 10 cut along line II-II of FIG. 1 passing through the passages 22 and 23. In FIG. 2, the thicknesses of the respective parts are exaggeratedly illustrated. The reaction unit 12 includes a fuel electrode frame 32, a separator 33, an air electrode frame 34, and a separator 35 in order in the thickness direction. Holes (passages 20 - 23) penetrate through the fuel electrode frame 32, the separator 33, the air electrode frame 34, and the separator 35. Inside the fuel electrode frame 32, the separator 33, the air electrode frame 34, and the separator 35, cells 26, current collectors 30, and interconnects 31 are disposed.

[0018] Figure 3 is a cross-sectional view of the cell 26. The cell 26 includes a fuel electrode 27, an air electrode 28, and an electrolyte 29 that separates the fuel electrode 27 and the air electrode 28. In this embodiment, a flat plate-shaped cell 26 will be described, but the present invention is not limited thereto. The cell 26 may be a metal-supported type (metal-supported flat plate type) in which electrodes and an electrolyte are supported by a porous body of a metal such as an Fe—Cr system. The cell 26 may be of an electrode-supported type or an electrolyte-supported type.

[0019] The material of the electrolyte 29 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 for 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 27 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 28 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 and the like.

[0022] Returning to FIG. 2 for description. The current collector 30 electrically connects the terminal 13 or the interconnector 31 adjacent in the thickness direction and the fuel electrode 27 of the cell 26 (see FIG. 3). Examples of the material of the current collector 30 include a porous body made of a metal such as Ni having gas permeability.

[0023] The interconnector 31 electrically connects the current collector 30 adjacent in the thickness direction and the air electrode 28 (see FIG. 3) of the cell 26. The material of the interconnector 31 is exemplified by stainless steel.

[0024] The fuel electrode frame 32 is a frame-shaped member disposed between the terminal 13 or the separator 35 and the separator 33 and surrounding the cell 26 and the current collector 30. The material of the fuel electrode frame 32 is exemplified by stainless steel.

[0025] The separator 33 is a frame-shaped member and is hermetically joined to the electrolyte 29 by a brazing material or the like, avoiding the air electrode 28 (see FIG. 3) of the cell 26. The material of the separator 33 is exemplified by stainless steel.

[0026] The air electrode frame 34 is a frame-shaped member disposed between the separator 33 and the separator 35 and surrounding the interconnector 31. The material of the air electrode frame 34 is exemplified by an insulator such as mica.

[0027] The separator 35 is a frame-shaped member and is hermetically joined to the interconnector 31 by a brazing material or the like. The material of the separator 35 is exemplified by stainless steel.

[0028] A fuel chamber 36 is provided inside the fuel electrode frame 32, and an air chamber 37 is provided inside the air electrode frame 34. The fuel chamber 36 is connected to the passages 20, 21 (see FIG. 1), and the air chamber 37 is connected to the passages 22, 23. The separators 33, 35 isolate the fuel chamber 36 and the air chamber 37 so that the fuel gas in the fuel chamber 36 and the oxidant gas in the air chamber 37 do not mix. A partition plate 38 disposed between the terminal 14 and the insulator 16 partitions the inside and outside of the stack 11. The material of the partition plate 38 is exemplified by stainless steel.

[0029] When the stack 11 is a fuel cell, examples of the fuel gas include hydrogen, carbon monoxide, and hydrocarbons, and examples of the oxidant gas include oxygen and air. When the stack 11 is an electrolyzer (the cell 26 is an electrolytic cell), 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. The stack 11 includes those capable of reversible operation between a fuel cell and an electrolyzer.

[0030] The operating temperature of the cell 26 is exemplified as 600 - 1000°C. The stack 11 is surrounded by a heat insulating material 47 to ensure the energy efficiency of heating the cell 26 to the operating temperature. Examples of the heat insulating material 47 include heat-resistant fibers such as ceramic wool, refractory ceramic fiber (RCF), and bio-soluble fiber (AES), and heat-resistant containers formed of heat-resistant fibers. Inside the heat insulating material 47, a heater 54 (described later) for heating the cell 26 to the operating temperature is arranged.

[0031] A pipe 24 for supplying fuel gas to the stack 11 from the outside of the heat insulating material 47 is connected to a passage 21 (see FIG. 1) of the stack 11. The fuel gas that has entered the passage 21 passes through the fuel chamber 36 and exits the stack 11 and the heat insulating material 47 through the passage 20 (see FIG. 1). A pipe 25 for supplying oxidant gas to the stack 11 from the outside of the heat insulating material 47 is connected to a passage 22 of the stack 11. The oxidant gas that has entered the passage 22 passes through the air chamber 37 and exits the stack 11 and the heat insulating material 47 through the passage 23. Examples of the material of the pipes 24 and 25 include stainless steel.

[0032] A plurality of cells 26 are electrically connected in series between the terminals 13 and 14 via a current collector 30 and an interconnector 31. When the stack 11 is a fuel cell, a load (not shown) is connected to the terminals 13 and 14. In a fuel cell, gaseous oxygen reacts with electrons at the air electrode 28 (see FIG. 3) of the cell 26 to generate oxide ions. The oxide ions that have moved through the electrolyte 29 react with the fuel gas at the fuel electrode 27 to generate electrons. As a result, a current flows through the load via the terminals 13 and 14.

[0033] When stack 11 is an electrolyzer, if the positive electrode of a power source (not shown) is connected to terminal 14 and the negative electrode of the power source is connected to terminal 13, a current flows through terminals 13 and 14, and electrons flow out toward the fuel electrode 27 of cell 26. The fuel gas that has entered the fuel chamber 36 is reduced at the fuel electrode 27. Since electrons are taken away at the air electrode 28, the oxide ions that have moved to the air electrode 28 through the electrolyte 29 are oxidized at the air electrode 28. As a result, energy carriers such as hydrogen and hydrocarbons are synthesized in stack 11.

[0034] Whether stack 11 is a fuel cell or an electrolyzer, a current flows through terminals 13 and 14, so Joule heat is generated at terminals 13 and 14. Terminal 13 includes a first portion 39 that overlaps with the reaction unit 12 inside stack 11 and a rod-shaped second portion 40 that extends outside stack 11. Since the second portion 40 is inside the heat insulating material 47 and extends outside stack 11, it is heated by the atmosphere around stack 11. Therefore, the second portion 40 is heated not only by Joule heat but also by the atmosphere.

[0035] Terminal 14 includes a first portion 43 that overlaps with the reaction unit 12 inside stack 11 and a rod-shaped second portion 44 that extends outside stack 11. Since the second portion 44 is inside the heat insulating material 47 and extends outside stack 11, it is heated by the atmosphere around stack 11. Therefore, the second portion 44 is heated not only by Joule heat but also by the atmosphere.

[0036] A transmission portion 41 is provided on the outer surface of the second portion 40 of terminal 13. The heat receiving portion 42 of the pipe 25 is arranged along the transmission portion 41 with a gap from the transmission portion 41. Since the heat receiving portion 42 is separated from the transmission portion 41 by air and the transmission portion 41 and the heat receiving portion 42 are electrically insulated, electric shock when touching the pipe 25 can be prevented.

[0037] The transmission portion 41 transfers the heat of terminal 13 to the oxidant gas flowing through the pipe 25 via the heat receiving portion 42. By using the heat of stack 11 to heat the oxidant gas, the cooling of cell 26 supplied with the oxidant gas can be reduced.

[0038] A cylindrical spiral-shaped heat receiving part 42 is arranged around the second part 40. Since the heat receiving area can be increased compared to the case where the heat receiving part 42 is linear, the amount of heat that the transfer part 41 gives to the oxidant gas can be increased.

[0039] A transfer part 45 is provided on the outer surface of the second part 44 of the terminal 14. The heat receiving part 46 of the pipe 24 is arranged along the transfer part 45 with a space therebetween. Since the transfer part 45 and the heat receiving part 46 are electrically insulated, electric shock when touching the pipe 24 can be prevented. Since the transfer part 45 is provided on the outer surface of the second part 44 of the terminal 14, the transfer part 45 and the heat receiving part 46 can be easily electrically insulated by arranging the heat receiving part 46 with a space from the transfer part 45 or the like.

[0040] The transfer part 45 transfers the heat of the terminal 14 to the fuel gas flowing through the pipe 24 via the heat receiving part 46. By using the heat of the stack 11 to heat the fuel gas, the cooling of the cell 26 supplied with the fuel gas can be reduced.

[0041] A cylindrical spiral-shaped heat receiving part 46 is arranged around the second part 44. Since the heat receiving area can be increased compared to the case where the heat receiving part 46 is linear, the amount of heat that the transfer part 45 gives to the fuel gas can be increased.

[0042] By using the heat dissipation of the terminals 13 and 14 to preheat the fuel gas and the oxidant gas supplied to the stack 11, energy loss can be reduced. Since both the fuel gas flowing through the pipe 24 and the oxidant gas flowing through the pipe 25 are heated using the terminals 13 and 14, energy loss can be reduced compared to the case of heating only one of the fuel gas and the oxidant gas.

[0043] The stack 11 is preferably capable of operating as an electrolysis device, that is, the cell 26 preferably has the function of an electrolysis cell. This is because the current flowing through the terminals 13 and 14 can be controlled by a power source (not shown) connected to the terminals 13 and 14, and heat generation of the terminals 13 and 14 due to Joule heat can be ensured.

[0044] With reference to FIG. 4, a hydrogen production apparatus 50 including an electrochemical stack 10 and a hot module 51 will be described. FIG. 4 is a block diagram of the hydrogen production apparatus 50. The hydrogen production apparatus 50 is an apparatus for producing hydrogen from water and includes a hot module 51.

[0045] The hot module 51 includes an electrochemical stack 10, a vaporizer 52 that generates steam supplied to the stack 11, a heat exchanger 53 that performs heat exchange between the gas supplied to the stack 11 and the gas generated by the stack 11, and a heater 54 that heats the stack 11. For reducing heat dissipation, in the hot module 51, the stack 11, the vaporizer 52, the heat exchanger 53, and the heater 54 are arranged inside a heat insulating material 47. Heat resistant fibers such as ceramic wool, RCF, and AES fill the gaps between the stack 11, the vaporizer 52, the heat exchanger 53, and the heater 54.

[0046] The vaporizer 52 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 52 contains hydrogen that reduces the oxidation of the catalyst contained in the fuel electrode 27 (see FIG. 3). The steam containing hydrogen exchanges heat with the hydrogen and oxygen generated by the stack 11 by the heat exchanger 53, and then is heated to the operating temperature of the stack 11 by the heater 54 and supplied to the fuel chamber 36 of the stack 11. Air exchanges heat with the hydrogen and oxygen generated by the stack 11 by the heat exchanger 53, and then is heated to the operating temperature of the stack 11 by the heater 54 and supplied to the air chamber 37 of the stack 11. The condenser 55 is a device for cooling hydrogen gas, and the liquefied water is supplied to the vaporizer 52 as raw water.

[0047] The second embodiment will be described with reference to FIG. 5. In the first embodiment, the case where the transmission parts 41 and 45 are provided on the outer surfaces of the terminals 13 and 14 was described. In the second embodiment, the case where the transmission parts 64 and 74 are provided inside the terminals 13 and 14 will be described. The same parts as those described in the first embodiment are denoted by the same reference numerals, and the following description thereof will be omitted.

[0048] FIG. 5 is a cross-sectional view of the electrochemical stack 60 in the second embodiment. The electrochemical stack 60 includes a solid oxide type stack 11, terminals 13 and 14 disposed on the stack 11, and tubes 24 and 25 for supplying gas to the stack 11. In FIG. 5, illustration of the middle portion of the stack 11 is omitted.

[0049] The terminal 13 includes a first portion 61 that overlaps the reaction unit 12 inside the stack 11 and a second portion 62 that extends outside the stack 11. Since the second portion 62 is inside the heat insulating material 47, in addition to Joule heat, it is heated by the atmosphere. The second portion 62 includes a cylindrical hollow portion 63 having a cavity inside. In this embodiment, the hollow portion 63 extends to the outside of the heat insulating material 47.

[0050] The tube 25 includes a first tube 65 and a second tube 68. The first tube 65 is connected to the portion of the hollow portion 63 outside the heat insulating material 47. An electrically insulating gasket 66 is disposed between the first tube 65 and the hollow portion 63, and the first tube 65 is connected to the hollow portion 63 by an electrically insulating ceramic screw 67, so the first tube 65 is electrically insulated from the terminal 13.

[0051] One end of the second tube 68 is connected to the portion of the hollow portion 63 inside the heat insulating material 47, and the other end is connected to the passage 22 of the stack 11. An electrically insulating gasket 69 is disposed between the second tube 68 and the hollow portion 63, and the second tube 68 is connected to the hollow portion 63 by an electrically insulating ceramic screw 70, so the second tube 68 is electrically insulated from the terminal 13.

[0052] The oxidant gas that enters the hollow portion 63 from the first tube 65 enters the passage 22 through the second tube 68. The transmission portion 64 (inner surface of the hollow portion 63) provided inside the hollow portion 63 transfers heat to the oxidant gas. By utilizing the heat dissipation of the terminal 13 to preheat the oxidant gas supplied to the stack 11, energy loss can be reduced.

[0053] The terminal 14 includes a first portion 71 that overlaps the reaction unit 12 inside the stack 11 and a second portion 72 that extends outside the stack 11. Since the second portion 72 is inside the heat insulating material 47, in addition to the Joule heat, it is heated by the atmosphere. The second portion 72 includes a cylindrical hollow portion 73 having a cavity inside. In the present embodiment, the hollow portion 73 extends to the outside of the heat insulating material 47.

[0054] The pipe 24 includes a first pipe 75 and a second pipe 78. The first pipe 75 is connected to the portion of the hollow portion 73 outside the heat insulating material 47. An electrically insulating gasket 76 is disposed between the first pipe 75 and the hollow portion 73, and the first pipe 75 is connected to the hollow portion 73 by an electrically insulating ceramic screw 77, so the first pipe 75 is electrically insulated from the terminal 14.

[0055] One end of the second pipe 78 is connected to the portion of the hollow portion 73 inside the heat insulating material 47, and the other end is connected to the passage 21 (see FIG. 1) of the stack 11. An electrically insulating gasket 79 is disposed between the second pipe 78 and the hollow portion 73, and the second pipe 78 is connected to the hollow portion 73 by an electrically insulating ceramic screw 80, so the second pipe 78 is electrically insulated from the terminal 14.

[0056] The fuel gas that enters the hollow portion 73 from the first pipe 75 enters the passage 21 through the second pipe 78. The transmission portion 74 (the inner surface of the hollow portion 73) provided inside the hollow portion 73 transfers heat to the fuel gas. By utilizing the heat dissipation of the terminal 14 to preheat the fuel gas supplied to the stack 11, energy loss can be reduced.

[0057] The transmission portions 64 and 74 are provided inside the terminals 13 and 14, and since the transmission portions 64 and 74 are provided on the inner surfaces of the hollow portions 63 and 73, heat is transferred from the transmission portions 64 and 74 provided on the inner surfaces of the hollow portions 63 and 73 to the fuel gas and oxidant gas flowing through the hollow portions 63 and 73. Therefore, the transmission portions 64 and 74 in the second embodiment can improve the heat transfer efficiency compared to the transmission portions 41 and 45 in the first embodiment.

[0058] Although the present invention has been described based on the embodiments, it is easily conceivable 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 gist of the present invention.

[0059] In the embodiment, the electrochemical stacks 10 and 60 to which the flat plate-shaped cell 26 is connected have been described, but it is not necessarily limited thereto. It is of course possible to adopt other cell designs than the flat plate shape for the electrochemical stack. Examples of other cell designs include a metal-supported flat plate shape, a cylindrical flat plate shape, a cylindrical horizontal stripe shape, and a cylindrical vertical stripe shape.

[0060] In the embodiment, the case where the oxidant gas is heated at the terminal 13 and the fuel gas is heated at the terminal 14 has been described, but it is not necessarily limited thereto. It is of course possible to heat the fuel gas at the terminal 13 and the oxidant gas at the terminal 14. Alternatively, it is of course possible to heat both the fuel gas and the oxidant gas at the terminal 13, or to heat both the fuel gas and the oxidant gas at the terminal 14.

[0061] In the embodiment, the case where both the fuel gas and the oxidant gas are heated at the terminals 13 and 14 has been described, but it is not necessarily limited thereto. It is of course possible to heat either the fuel gas or the oxidant gas at the terminal 13 or the terminal 14.

[0062] In the embodiment, the hydrogen production apparatus 50 and the hot module 51 including the electrochemical stack 10 have been described, but it is not necessarily limited thereto. It is of course possible for the hydrogen production apparatus 50 and the hot module 51 to include the electrochemical stack 60 instead of the electrochemical stack 10.

[0063] In the first embodiment, the case where the entire heat receiving portions 42 and 46 are arranged inside the heat insulating material 47 has been described, but it is not necessarily limited thereto. It is of course possible to arrange a part of the heat receiving portions 42 and 46 outside the heat insulating material 47, like the hollow portions 63 and 73 of the second embodiment.

[0064] In the second embodiment, the case where a part of the hollow portions 63 and 73 is disposed outside the heat insulating material 47 has been described, but it is not necessarily limited to this. It is of course possible to dispose the entire hollow portions 63 and 73 inside the heat insulating material 47 as in the heat receiving portions 42 and 46 of the first embodiment.

[0065] In the first embodiment, the case where the cylindrical spiral heat receiving portions 42 and 46 are disposed around the rod-shaped second portions 40 and 44 has been described, but it is not necessarily limited to this. The second portions 40 and 44 may be formed in a flat plate shape. In this case, in order to increase the heat receiving area, the heat receiving portions 42 and 46 are formed in a shape of a spiral or a meandering planar curve, and the second portion 40 and the heat receiving portion 42 are disposed apart from each other, or the second portion 44 and the heat receiving portion 46 are disposed apart from each other.

[0066] In the first embodiment, the case where air intervenes between the second portion 40 and the heat receiving portion 42 or between the second portion 44 and the heat receiving portion 46 in order to electrically insulate the terminals 13 and 14 and the tubes 24 and 25 from each other has been described, but it is not necessarily limited to this. It is of course possible to dispose an inorganic adhesive or an inorganic filler having heat resistance and high thermal conductivity between the second portion 40 and the heat receiving portion 42 or between the second portion 44 and the heat receiving portion 46.

[0067] In the second embodiment, the case where gaskets 66, 69, 76, and 79 are disposed between the first tubes 65 and 75 and the second tubes 68 and 78 and the hollow portions 63 and 73, and the first tubes 65 and 75 and the second tubes 68 and 78 and the hollow portions 63 and 73 are joined using screws 67, 70, 77, and 80 has been described, but it is not necessarily limited to this. It is of course possible to form a hole in the hollow portion 63 and 73 that is larger than the first tubes 65 and 75 and the second tubes 68 and 78 from which the flanges are omitted, fit the hole and the tube with a clearance fit, and seal the gap between the hole and the tube with an inorganic adhesive having heat resistance and electrical insulation to join the hollow portion 63 and 73 and the tube.

[0068] Although not described in the second embodiment, it is of course possible to provide fins (protrusions) on the transmission portions 64 and 74. When fins are provided on the transmission portions 64 and 74, the heat transfer area is increased, so that the heat transfer efficiency can be improved.

Explanation of Symbols

[0069] 10, 60 Electrochemical Stack 11 Stack 13, 14 Terminals 24, 25 Tubes 26 Cell 27 Fuel Electrode (Electrode) 28 Air Electrode (Electrode) 29 Electrolyte 40, 44, 62, 72 Parts outside the Stack 63, 73 Hollow Parts 41, 45, 64, 74 Transfer Parts 47 Heat Insulating Material 50 Hydrogen Production Device 51 Hot Module 52 Vaporizer 53 Heat Exchanger 54 Heater

Claims

1. A solid oxide type stack in which a plurality of cells each containing an electrolyte that separates 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 cells flows, an electrochemical stack comprising: The terminal has a portion extending outside the stack, The terminal includes a transfer portion that transfers heat of the terminal to the gas flowing through the tube, An electrochemical stack in which the transfer portion and the tube are electrically insulated.

2. The transfer portion is provided on an outer surface of the portion of the terminal, The electrochemical stack according to claim 1, wherein heat is transferred from the transfer portion to an outer surface of the tube.

3. A part of the terminal is hollow, The tube is connected to the hollow portion of the terminal, The transfer portion is provided inside the terminal, The electrochemical stack according to claim 1, wherein the gas is supplied to the cell through the transfer portion.

4. The cell has a 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 exchanges heat with the gas supplied to the electrochemical stack, A heater for heating the electrochemical stack, A hot module comprising the electrochemical stack, the vaporizer, the heat exchanger, and a heat insulating material in which the heater is disposed inside.

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

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