Stack, hot module, and hydrogen production device

Abstract

To provide a stack, a hot module and a hydrogen production device, capable of reducing the generation of a lower temperature segment.SOLUTION: The stack comprises: a laminate in which, a plurality of electrolytic cells each including an electrolyte separating an anode and a cathode in a thickness direction are disposed in the thickness direction with electrolytic cells connected to each other in series therein; two conductive plates disposed outside the laminate in the thickness direction, electrically connected to the electrolytic cells, and having mutually different polarities; and terminals respectively connected to the two conductive plates to protrude in a direction intersecting the thickness direction, wherein at least one of the terminals is bent toward the laminate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] A stack, which includes a laminate of multiple electrolytic cells containing an electrolyte that separates the anode and cathode, and terminals connected in series to the electrolytic cells, uses the electrical and thermal energy supplied to the stack to electrolyze fuel gases such as water vapor and carbon dioxide, producing energy carriers such as hydrogen and hydrocarbons. Because the electrolysis of fuel gas is an endothermic reaction, energy is usually supplied to the stack with the goal of reaching a thermal neutral point where the heat generated by Joule heat and the heat absorbed are balanced. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2016-538420 Summary of the Invention [Problem to be solved by the invention]

[0004] In the prior art disclosed in Patent Document 1, if the amount of energy supplied to the stack is set to the required amount in an attempt to increase the ratio of the energy of carriers generated by the stack to the energy supplied to the stack (energy efficiency), low-temperature areas are more likely to appear in the stack, reducing the amount of energy carriers generated and potentially reducing energy efficiency.

[0005] The present invention has been made to solve this problem, and has as its object to provide a stack, a hot module and a hydrogen generating apparatus that can reduce the generation of low-temperature portions. [Means for solving the problem]

[0006] A first aspect for achieving this object is a stack comprising: a laminate in which a plurality of electrolytic cells containing an electrolyte that separates an anode and a cathode in the thickness direction are arranged in the thickness direction and the electrolytic cells are connected in series to each other; two conductive plates with opposite polarities that are arranged on the outer side of the laminate in the thickness direction and electrically connected to the electrolytic cells; and terminals that are connected to the two conductive plates, respectively, and protrude in a direction intersecting the thickness direction, at least one of the terminals being bent toward the laminate.

[0007] In the second embodiment, the two terminals in the first embodiment are bent toward the laminate.

[0008] In a third embodiment, the terminals in the second embodiment protrude in the same direction.

[0009] In a fourth embodiment, the terminals in the second embodiment protrude in different directions from each other.

[0010] In a fifth aspect, in any of the first to fourth aspects, when the laminate is divided into three equal parts in the thickness direction into two end parts and a central part sandwiched between the two end parts, the terminal includes an opposing part facing the central part.

[0011] In a sixth aspect, in the fifth aspect, the facing portion includes a portion whose cross-sectional area is smaller than the cross-sectional area of ​​the connection portion where the terminal is connected to the conductive plate.

[0012] A seventh aspect is a hot module comprising a stack of any one of the first to fifth aspects, a vaporizer that generates steam to be supplied to the stack, a heat exchanger that exchanges heat with the gas supplied to the stack, a heater for heating the stack, and insulation in which the stack, vaporizer, heat exchanger, and heater are disposed.

[0013] An eighth aspect is a hydrogen production device comprising the hot module of the seventh aspect. [Effects of the Invention]

[0014] According to the present invention, the terminals connected to the conductive plates are bent toward the laminate, so that Joule heat from the terminals can be utilized to reduce the occurrence of low-temperature portions in the laminate. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a perspective view of a stack according to the first embodiment. [Figure 2] FIG. 1 is a cross-sectional view of an electrolysis cell. [Figure 3] FIG. [Figure 4] FIG. 4 is a front view of the stack as seen from the direction of arrow IV in FIG. 3. [Figure 5] FIG. 1 is a block diagram of a hydrogen production device. [Figure 6] FIG. 10 is a front view of a stack according to a second embodiment. [Figure 7] FIG. 7 is a side view of the stack as seen in the direction of arrow VII in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0016] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Fig. 1 is a perspective view of a stack 10 according to a first embodiment. The stack 10 is a device that electrolyzes fuel gases such as water vapor and carbon dioxide to produce energy carriers such as hydrogen and hydrocarbons. The stack 10 includes a stack that is capable of reversible operation between producing energy carriers and acting as a fuel cell that generates electricity from the energy carriers.

[0017] The stack 10 includes a laminate 12 in which reaction units 11 are stacked in the thickness direction, conductive plates 13 and 15 arranged on both sides of the reaction units 11 in the thickness direction, and end plates 17 and 18 that sandwich the laminate 12 and the conductive plates 13 and 15 in the thickness direction. The conductive plates 13 and 15 are electrically connected to the laminate 12. The laminate 12 is made up of, for example, about 10 to 30 reaction units 11 stacked together.

[0018] A terminal 14 is provided on the conductive plate 13, and a terminal 16 is provided on the conductive plate 15. The conductive plates 13, 15 and terminals 14, 16 are made of stainless steel, for example. An insulator 19 is disposed between the end plate 17 and the conductive plate 13, and an insulator 20 is disposed between the end plate 18 and the conductive plate 15.

[0019] Bolts 21 are arranged at the four corners of the periphery of the stack 10, penetrating the laminate 12, the conductive plates 13 and 15, the insulators 19 and 20, and the end plates 17 and 18 in the thickness direction. The laminate 12, the conductive plates 13 and 15, the insulators 19 and 20, and the end plates 17 and 18 are fastened together by the bolts 21.

[0020] The four spaces that penetrate the periphery of the stack 10 in the thickness direction function as a passage 22 through which gas enters the cathode chamber 36 (described later) of the reaction unit 11 from outside the stack 10, a passage 23 through which gas exits the stack 10 from the cathode chamber 36, a passage 24 through which gas enters the anode chamber 38 (described later) of the reaction unit 11 from outside the stack 10, and a passage 25 through which gas exits the stack 10 from the anode chamber 38.

[0021] 2 is a cross-sectional view of the stack 10 taken along line II-II in FIG. 1, which passes through the passages 22 and 23, and shows the components constituting one reaction unit 11 separated in the thickness direction and exploded. The thickness of each part is exaggerated in FIG. 2. The reaction unit 11 includes, in order in the thickness direction, an interconnector 26, a cathode frame 27, a cell 28 with separator, and an anode frame 29.

[0022] The separator-equipped cell 28 includes an electrolytic cell 30 and a separator 34 disposed in an electrolyte 31 of the electrolytic cell 30. Holes (passages 22, 23) penetrate the interconnector 26, the cathode frame 27, the separator 34, and the anode frame 29.

[0023] The electrolytic cell 30 includes an electrolyte 31, and a cathode 32 and an anode 33 separated by the electrolyte 31. The material of the electrolyte 31 is a solid oxide, such as stabilized zirconia, a ceria-based solid solution, or a solid solution of alumina with one or more selected from stabilized zirconia and a ceria-based solid solution. Examples of stabilizers for stabilized zirconia include CaO, MgO, YO, ScO, and YbO. Examples of elements that dissolve in ceria in a ceria-based solid solution include Gd, Sm, and Y.

[0024] Examples of the material for the cathode 32 include a material containing a catalyst containing Ni and zirconia with Y as a solid solution, and a material containing a catalyst containing Ni and ceria with Gd as a solid solution. Examples of the catalyst include Ni, Ni-based alloys, and cermet, which is a composite (sintered body) of NiO and an oxide (solid electrolyte).

[0025] The material of the anode 33 is a perovskite 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 is exemplified.

[0026] The separator 34 is a frame-shaped member provided with an opening larger than the anode 33. The separator 34 is made of, for example, stainless steel. The separator 34 is airtightly joined to the electrolyte 31 with brazing material or the like, avoiding the anode 33.

[0027] The interconnectors 26 are conductive plate-like members arranged on both sides in the thickness direction of the electrolytic cell 30. The interconnectors 26 electrically connect the reaction units 11 adjacent to each other in the thickness direction. An example of the material of the interconnectors 26 is stainless steel.

[0028] The cathode frame 27 is a frame-shaped member disposed between the interconnector 26 and the separator 34. The cathode frame 27 is made of, for example, stainless steel. The cathode frame 27 surrounds the electrolytic cell 30 and a current collector 35 provided in the center of the interconnector 26.

[0029] The current collector 35 electrically connects the cathode 32 and the interconnector 26. The material of the current collector 35 is, for example, a porous body made of a gas-permeable metal such as Ni. Inside the cathode frame 27, a cathode chamber 36 is provided which is surrounded by the interconnector 26 and the separator-equipped cell 28.

[0030] The anode frame 29 is a frame-shaped member disposed between the interconnector 26 and the separator 34. An example of the material of the anode frame 29 is an insulator such as mica. The anode frame 29 surrounds a current collector 37 provided in the center of the interconnector 26. The current collector 37 electrically connects the anode 33 and the interconnector 26. In this embodiment, the current collector 37 is formed integrally with the interconnector 26, but this is not limitative. It is of course possible for the current collector 37 to be a member separate from the interconnector 26.

[0031] An anode chamber 38 surrounded by the interconnector 26 and the separator-equipped cell 28 is provided inside the anode frame 29. A separator 34 separates the cathode chamber 36 from the anode chamber 38, preventing the fuel gas in the cathode chamber 36 from mixing with the oxidizer gas (oxygen, air, etc.) in the anode chamber 38. Examples of fuel gas include water vapor, carbon dioxide, and a mixture thereof.

[0032] Returning to Figure 1, an interconnector 26 in contact with the anode chamber 38 (see Figure 2) is connected to the conductive plate 13 provided with the terminal 14, and an interconnector 26 in contact with the cathode chamber 36 is connected to the conductive plate 15 provided with the terminal 16. A plurality of electrolytic cells 30 (see Figure 2) arranged in the thickness direction of the stack 12 are connected in series to the conductive plates 13, 15, which have opposite polarities. The terminals 14, 16 protrude in the same direction from one of the four side surfaces of the stack 10, which has a substantially rectangular parallelepiped shape.

[0033] Pipes (not shown) through which gas flows are connected to the passages 22, 23, 24, and 25, respectively. The fuel gas that enters the passage 22 from the pipe passes through a cathode chamber 36 (see FIG. 2) provided in each reaction unit 11, and then passes through passage 23 to exit the stack 10. The oxidant gas that enters the passage 24 from the pipe passes through an anode chamber 38 provided in each reaction unit 11, and then passes through passage 25 to exit the stack 10.

[0034] When the positive electrode of a power supply (not shown) is connected to terminal 14 and the negative electrode of the power supply is connected to terminal 16, electrons flow toward the cathode 32 of the electrolytic cell 30 (see FIG. 2). The fuel gas that enters the cathode chamber 36 is reduced at the cathode 32. Because electrons are taken away at the anode 33 of the electrolytic cell 30, oxide ions that have migrated to the anode 33 via the electrolyte 31 are oxidized at the anode 33. As a result, energy carriers such as hydrogen and hydrocarbons are synthesized in the electrolytic cell 30.

[0035] Because the electrolysis of water vapor, carbon dioxide, and the like contained in the fuel gas is an endothermic reaction, the temperature of the electrolytic cell 30 (the temperature of the exhaust gas flowing through the passages 23 and 25) decreases as the current density increases, compared to the temperature at the open circuit voltage of the electrolytic cell 30 when current begins to flow (the average voltage of the electrolytic cell 30 when the current density is 0). As the current density increases further, the temperature of the electrolytic cell 30 begins to rise due to Joule heat, and reaches a thermal neutral point where endothermic and exothermic reactions are balanced. When the current density of the reaction unit 11 becomes lower than the current density of the reaction unit 11 at the thermal neutral point, endothermic reaction in the reaction unit 11 becomes dominant, and the temperature decreases. When the current density of the reaction unit 11 becomes higher than the current density of the reaction unit 11 at the thermal neutral point, exothermic reaction in the reaction unit 11 becomes dominant, and the temperature increases.

[0036] Because the Joule heat of the conductive plates 13 and 15 is greater than the Joule heat of the reaction unit 11, the Joule heat of the conductive plates 13 and 15 is transferred to the laminate 12, and the temperature of the center of the laminate 12 in the stacking direction of the reaction unit 11 tends to be lower than the temperature of both ends in the stacking direction. This tendency becomes more pronounced as the current flowing through the stack 10 decreases. Since the electrolytic cell 30 exhibits more active energy carrier synthesis at higher temperatures, it is preferable to reduce the occurrence of low-temperature portions in the laminate 12 and reduce temperature unevenness in the laminate 12 in order to activate the energy carrier synthesis. In the stack 10, the terminals 14 and 16 connected to the conductive plates 13 and 15, respectively, are bent toward the laminate 12, and the Joule heat of the terminals 14 and 16 is used to reduce temperature unevenness in the laminate 12.

[0037] Fig. 3 is a side view of stack 10, and Fig. 4 is a front view of stack 10 as seen in the direction of arrow IV in Fig. 3. Fig. 4 omits the illustration of stack 10 except for the portions of stack 10 from which terminals 14 and 16 protrude. Terminals 14 and 16 are the inlets and outlets of current to and from conductive plates 13 and 15, respectively. For ease of explanation, the thickness of laminate 12 is divided into three equal parts in the thickness direction, dividing laminate 12 into end portion 39 close to conductive plate 13, end portion 40 close to conductive plate 15, and central portion 41 sandwiched between end portions 39 and 40.

[0038] 4, terminal 14 includes a connection portion 42 connected to conductive plate 13 and protruding from laminate 12 and end plate 17, a bent portion 43 bent toward laminate 12, a facing portion 44 facing central portion 41 of laminate 12, a bent portion 45 bent in a direction away from laminate 12, and an end portion 46 to which a power source (not shown) is connected. Terminal 16 includes a connection portion 47 connected to conductive plate 15 and protruding from laminate 12 and end plate 18, a bent portion 48 bent toward laminate 12, a facing portion 49 facing central portion 41 of laminate 12, a bent portion 50 bent in a direction away from laminate 12, and an end portion 51 to which a power source (not shown) is connected.

[0039] In this embodiment, terminal 14 is bent at a nearly right angle at bent portion 43 and is bent at a nearly right angle at bent portion 45. Similarly, terminal 16 is bent at a nearly right angle at bent portion 48 and is bent at a nearly right angle at bent portion 50. There is a certain distance between facing portion 44 and laminate 12 to ensure electrical insulation, and the distance between bent portion 43 and laminate 12 is approximately equal to the distance between bent portion 45 and laminate 12. Similarly, there is a certain distance between facing portion 49 and laminate 12 to ensure electrical insulation, and the distance between bent portion 48 and laminate 12 is approximately equal to the distance between bent portion 50 and laminate 12.

[0040] As shown in Figure 3, end 46 of terminal 14 and end 51 of terminal 16 are aligned side by side at the center in the thickness direction of central portion 41 of laminate 12. The width of terminal 14 gradually narrows from connection portion 42 (see Figure 4) to end 46, and the thickness of terminal 14 is approximately constant, so the cross-sectional area of ​​terminal 14 gradually decreases from connection portion 42 to end 46. The cross-sectional area of ​​facing portion 44 is smaller than the cross-sectional area of ​​connecting portion 42, and the cross-sectional area of ​​bent portion 45 of facing portion 44 is the smallest.

[0041] The end portions 39 and the central portion 41 of the laminate 12 are heated by Joule heat from the terminals 14. The temperature of the central portion 41 tends to be lower than the temperature of the end portions 39, but because the opposing portions 44 of the terminals 14 face the central portion 41, the temperature of the central portion 41 can be raised by Joule heat from the opposing portions 44. This reduces uneven temperature in the laminate 12.

[0042] Because the cross-sectional area of ​​the facing portion 44 is smaller than the cross-sectional area of ​​the connecting portion 42, the Joule heat of the facing portion 44 can be made larger than the Joule heat of the connecting portion 42. Since the amount of heat that the center portion 41 of the laminate 12 receives from the facing portion 44 can be made larger, the temperature unevenness of the laminate 12 can be further reduced.

[0043] Similarly, the width of terminal 16 gradually narrows from connection portion 47 (see FIG. 4) to end portion 51, and because the thickness of terminal 16 is approximately constant, the cross-sectional area of ​​terminal 16 gradually decreases from connection portion 47 to end portion 51. The cross-sectional area of ​​facing portion 49 is smaller than the cross-sectional area of ​​connecting portion 47, and the cross-sectional area of ​​bent portion 50 of facing portion 49 is the smallest.

[0044] The end portions 40 and the central portion 41 of the laminate 12 are heated by Joule heat from the terminals 16. The temperature of the central portion 41 tends to be lower than the temperature of the end portions 40, but because the opposing portions 49 of the terminals 16 face the central portion 41, the temperature of the central portion 41 can be raised by Joule heat from the opposing portions 49. This reduces uneven temperature in the laminate 12.

[0045] Because the cross-sectional area of ​​the facing portion 49 is smaller than the cross-sectional area of ​​the connecting portion 47, the Joule heat of the facing portion 49 can be made larger than the Joule heat of the connecting portion 47. Since the amount of heat that the center portion 41 of the laminate 12 receives from the facing portion 49 can be made larger, the temperature unevenness of the laminate 12 can be further reduced.

[0046] Because the facing portion 44 of the terminal 14 and the facing portion 49 of the terminal 16 are aligned horizontally in the central portion 41 of the laminate 12, the central portion 41 can be heated by utilizing the Joule heat of the facing portions 44, 49. Compared to when one of the terminals 14, 16 is used for heating, the Joule heat applied to the central portion 41 can be increased, further reducing unevenness in the temperature of the laminate 12.

[0047] Bent portion 45 of terminal 14 and bent portion 50 of terminal 16 are aligned side by side at the center position in the thickness direction of central portion 41 of laminate 12. Bent portion 45 has the smallest cross-sectional area of ​​opposing portion 44, and bent portion 50 has the smallest cross-sectional area of ​​opposing portion 49, so bent portions 45, 50 have the largest Joule heat. Bent portions 45, 50 have the largest Joule heat, so the center position in the thickness direction of central portion 41, which is likely to have the lowest temperature, can be heated, further reducing temperature unevenness in laminate 12.

[0048] In this embodiment, a hook-shaped metal fitting including a facing portion 44, a bent portion 45, and an end portion 46 is welded at a bent portion 43 to a conductive plate 13 provided with a connecting portion 42. Also, a hook-shaped metal fitting including a facing portion 49, a bent portion 50, and an end portion 51 is welded at a bent portion 48 to a conductive plate 15 provided with a connecting portion 47. This makes it easier to manufacture the terminals than when terminals 14, 16 are made by bending a metal plate twice.

[0049] 5 is a block diagram of a hydrogen production apparatus 60. The hydrogen production apparatus 60 includes a hot module 61 including a stack 10. The hot module 61 includes the stack 10, a vaporizer 62 that generates water vapor to be supplied to the cathode chamber 36 of the stack 10, a heat exchanger 63 that exchanges heat between the gas supplied to the stack 10 and the gas generated by the stack 10, and a heater 64 that heats the stack 10. To reduce heat radiation, the hot module 61 has the stack 10, the vaporizer 62, the heat exchanger 63, and the heater 64 arranged inside a thermal insulation material 65. Heat-resistant fibers such as ceramic wool, RCF, and AES fill the gaps between the stack 10, the vaporizer 62, the heat exchanger 63, and the heater 64.

[0050] The vaporizer 62 includes a heat exchanger that exchanges heat with the high-temperature gas containing oxygen produced by the stack 10, and heats water to produce steam. The steam produced by the vaporizer 62 contains hydrogen, which reduces oxidation of the catalyst contained in the cathode 32 (see FIG. 2). The hydrogen-containing steam exchanges heat with the hydrogen and oxygen produced by the stack 10 in a heat exchanger 63, is heated to the operating temperature of the stack 10 by a heater 64, and is supplied to the cathode chamber 36 of the stack 10. The air exchanges heat with the hydrogen and oxygen produced by the stack 10 in a heat exchanger 63, is heated to the operating temperature of the stack 10 by a heater 64, and is supplied to the anode chamber 38 of the stack 10. The condenser 66 is a device that cools the hydrogen gas, and the liquefied water is supplied to the vaporizer 62 as raw water.

[0051] The hot module 61 and the hydrogen production device 60 include the stack 10 having the terminals 14, 16, which can reduce the occurrence of low-temperature portions of the stack 12 due to Joule heat of the terminals 14, 16. This can improve the energy efficiency of the hot module 61 and the hydrogen production device 60.

[0052] A second embodiment will be described with reference to Figures 6 and 7. In the first embodiment, a stack 10 in which terminals 14, 16 protrude in the same direction was described. In contrast, in the second embodiment, a stack 70 in which terminals 71, 72 protrude in different directions will be described. In the second embodiment, parts that are the same as those described in the first embodiment are given the same reference numerals as in the first embodiment, and the following description will be omitted.

[0053] Fig. 6 is a front view of stack 70 in the second embodiment. Fig. 7 is a side view of stack 70 as seen in the direction of arrow VII in Fig. 6. Stack 70 includes laminate 12 and two conductive plates 13 and 15 of opposite polarities that are arranged on the outer side of laminate 12 in the thickness direction. Terminal 71 is connected to conductive plate 13, and terminal 72 is connected to conductive plate 15.

[0054] End 46 of terminal 71 is located at end 40 of laminate 12, and end 51 of terminal 72 is located at end 39 of laminate 12. A hole 73 is provided between bent portions 43 and 45 of terminal 71. A hole 74 is provided between bent portions 48 and 50 of terminal 72. Hole 73 penetrates terminal 71 in the thickness direction, and hole 74 penetrates terminal 72 in the thickness direction.

[0055] The width and thickness of terminal 71 are approximately constant from connecting portion 42 to end portion 46, and the width of hole 73 is widest at facing portion 44, so the cross-sectional area of ​​facing portion 44 is smaller than the cross-sectional area of ​​connecting portion 42. The width and thickness of terminal 72 are approximately constant from connecting portion 47 to end portion 51, and the width of hole 77 is widest at facing portion 49, so the cross-sectional area of ​​facing portion 49 is smaller than the cross-sectional area of ​​connecting portion 47.

[0056] The end portions 39, 40 and the central portion 41 of the laminate 12 are heated by Joule heat from the terminals 71. The temperature of the central portion 41 tends to be lower than the temperature of the end portions 39, 40, but because the opposing portion 44, which has the smallest cross-sectional area, faces the central portion 41, the temperature of the central portion 41 can be raised by Joule heat from the opposing portion 44. This reduces temperature unevenness in the laminate 12.

[0057] Similarly, the end portions 39, 40 and the central portion 41 of the laminate 12 are heated by Joule heat from the terminals 72. The temperature of the central portion 41 tends to be lower than the temperature of the end portions 39, 40, but because the opposing portion 49, which has the smallest cross-sectional area, faces the central portion 41, the temperature of the central portion 41 can be raised by the Joule heat of the opposing portion 49. This reduces temperature unevenness in the laminate 12.

[0058] Because the facing portion 44 of the terminal 71 and the facing portion 49 of the terminal 72 are arranged side by side with the central portion 41 of the laminate 12 in between, the central portion 41 can be heated by utilizing the Joule heat of the facing portions 44, 49. Compared to when heating is performed using only one of the terminals 71, 72, the Joule heat applied to the central portion 41 can be increased, and further, Joule heat can be applied to a wider range of the central portion 41, thereby further reducing unevenness in the temperature of the laminate 12.

[0059] The portion of opposing portion 44 of terminal 71 with the smallest cross-sectional area and the portion of opposing portion 49 of terminal 72 with the smallest cross-sectional area are disposed at the center position in the thickness direction of central portion 41 of laminate 12. Because the center position in the thickness direction of central portion 41, which is the portion of opposing portions 44, 49 with the greatest Joule heat and is therefore likely to have the lowest temperature, can be heated, it is possible to further reduce temperature unevenness in laminate 12.

[0060] The present invention has been described above based on the embodiments, but the present invention is not limited to the above embodiments, and it can be easily inferred that various improvements and modifications are possible within the scope of the present invention.

[0061] In the embodiment, the terminals 14, 16, 71, 72 are bent at approximately right angles at the bent portions 43, 45, 48, 50, but this is not necessarily limited to this. If the terminals 14, 16, 71, 72 are bent toward the laminate 12, the laminate 12 is heated by Joule heat of the terminals 14, 16, 71, 72, so the bending angles of the terminals 14, 16, 71, 72 at the bent portions 43, 45, 48, 50 are set appropriately.

[0062] In the embodiment, the case where Joule heat of the terminals 14, 16, 71, and 72 is transferred to the laminate 12 via air has been described, but this is not necessarily limited to this. A thermally conductive material such as cement having electrical insulation may be filled between the terminals 14 and 71 and the laminate 12, and Joule heat may be transferred to the laminate 12 via the thermally conductive material.

[0063] In the embodiment, the cross-sectional area of ​​the terminals is reduced by narrowing the width of the terminals 14, 16 or by drilling holes 73, 74 in the terminals 71, 72, but this is not necessarily limited to this. For example, it is of course possible to reduce the cross-sectional area of ​​the terminals by reducing their thickness.

[0064] In the embodiment, the stack 10 has a flat cell design. The flat stack 10 may be an electrode-supported type or an electrolyte-supported type. It may also be a metal-supported type (metal-supported flat plate type) in which the cathode, anode, and electrolyte are supported by a porous body of a metal such as an Fe-Cr system.

[0065] In the embodiment, the electrolytic cell 30 has a rectangular shape, but this is not necessarily limited to this. The shape of the electrolytic cell 30 may be circular or elliptical, or may be polygonal other than a rectangular shape, such as a triangle or pentagon.

[0066] In the embodiment, the case where the electrolyte 31 having oxide ion conductivity is used has been described, but this is not necessarily limited to this. It is of course possible to use an electrolyte 31 that has proton conductivity under the operating conditions of the electrolytic cell 30. Examples of substances that exhibit proton conductivity under the operating conditions of the electrolytic cell 30 include perovskite-type oxides such as SrZrO3 and BaZrO3, in which the B site is substituted with trivalent metal ions such as Y or In, pyrochlore-type oxides, and phosphates.

[0067] In the embodiment, the gas passages 22, 23, 24, and 25 are built into the stack 10, but this is not necessarily limited to this. It is of course possible to connect manifolds serving as the gas passages 22, 23, 24, and 25 to the electrolysis cell and provide them outside the electrolysis cell. Examples of materials for the manifolds include ceramics with high high-temperature strength. [Explanation of symbols]

[0068] 10,70 stack 12 Laminate 13,15 Conductive plate Terminals 14, 16, 71, 72 30 electrolysis cells 31 Electrolytes 32 Cathode 33 Anode 39,40 End 41 Central part 42,47 Connection 44,49 Opposite part 60 Hydrogen production equipment 61 Hot Module 62 Vaporizer 63 Heat exchanger 64 Heater 65 Insulation

Claims

1. a stack of electrolytic cells arranged in a thickness direction, the electrolytic cells including an electrolyte separating an anode and a cathode in the thickness direction, the electrolytic cells being connected in series with each other; two conductive plates having different polarities and arranged on outer sides of the laminate in the thickness direction and electrically connected to the electrolysis cell; a terminal connected to each of the two conductive plates and protruding in a direction intersecting the thickness direction, A stack in which at least one of the terminals is bent toward the laminate.

2. 2. The stack according to claim 1, wherein two of the terminals are bent toward the laminate.

3. 3. The stack of claim 2, wherein said terminals project in the same direction.

4. 3. The stack of claim 2, wherein the terminals project in different directions.

5. When the laminate is divided into three equal parts in the thickness direction into two end parts and a central part sandwiched between the two end parts, The stack according to claim 3 or 4, wherein the terminal includes an opposing portion facing the central portion.

6. The stack according to claim 5 , wherein the facing portion includes a portion having a cross-sectional area smaller than a cross-sectional area of ​​a connection portion where the terminal is connected to the conductive plate.

7. A stack according to any one of claims 1 to 4; a vaporizer that generates steam to be supplied to the stack; a heat exchanger that exchanges heat with the gas supplied to the stack; a heater for heating the stack; a hot module comprising a thermal insulator in which the stack, the vaporizer, the heat exchanger, and the heater are disposed;

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

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