Hot module

Abstract

To provide a hot module capable of reducing generation of a low-temperature portion in a stack.SOLUTION: A hot module includes: a laminated body that has a plurality of electrochemical cells, each containing an electrolyte that separates an anode and a cathode, which are stacked and connected in series; stacks that are disposed on both sides in a stacking direction of the electrochemical cells, of the laminated body, and are connected in series with the electrochemical cells, each stack having two terminals of opposite polarity; and electric lines that are connected to connection portions of the terminals and connect the plurality of stacks in series. The hot module also includes a proximity region where at least either of two end surfaces of the stack located at both ends in the stacking direction of the electrochemical cells is located near some part of the electric line, and a distance between the electric line at the proximity region and the end surface is shorter than a distance between the connection portion closest to the proximity region and the end surface at the proximity region.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a hot module including a stack of electrolysis cells. [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 hot module that can reduce the occurrence of low-temperature portions in the stack. [Means for solving the problem]

[0006] A first aspect of a hot module for achieving this objective is a hot module including: a stack including electrolytic cells each containing an electrolyte separating an anode and a cathode, the electrolytic cells being stacked and connected in series; two terminals of opposite polarity arranged on either side of the stack in the stacking direction of the electrolytic cells and connected in series to the electrolytic cells; and an electric wire connected to the connection part of the terminals and connecting the stack in series; a proximity part where at least one of two end faces of the stack located at both ends in the stacking direction of the electrolytic cells and a part of the electric wire are located close to each other; and the distance between the electric wire and the end face in the proximity part is shorter than the distance between the connection part located closest to the proximity part and the end face in the proximity part.

[0007] A second aspect of the present invention is the first aspect, including stacks arranged along the stacking direction of the electrolysis cells, and the adjacent portion is provided between stacks adjacent to each other in the stacking direction of the electrolysis cells.

[0008] A third aspect is the first or second aspect, including a stack arranged in a direction intersecting the stacking direction of the electrolytic cells, in which the stacks have connection portions arranged on opposite sides of an imaginary plane that includes the direction in which the stacks are arranged and the stacking direction of the electrolytic cells, and the adjacent portion includes a part of an electric wire connected to the connection portion of the stack.

[0009] A fourth aspect includes a stack according to the first or second aspect, arranged so as to intersect with the stacking direction of the electrolysis cells, in which the connection portions of the stack are arranged facing oppositely, and the adjacent portion includes a part of the electric wire connected to the connection portion of the stack.

[0010] In a fifth aspect, in any one of the first to fourth aspects, the electric wire has an electrical resistance per unit length of the proximal portion equal to or greater than the electrical resistance per unit length of the portion other than the proximal portion. [Effects of the Invention]

[0011] According to the present invention, portions of the electric wires are located close to the end faces of the stacks located at both ends in the stacking direction of the electrolysis cell. The distance between the electric wires and the end faces in the close portions is shorter than the distance between the connection portions located closest to the close portions and the end faces in the close portions. Therefore, Joule heat from the electric wires is transferred to the end faces of the stacks in the close portions, heating the stack. This reduces the occurrence of low-temperature portions in the stack. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a block diagram of a hot module according to the first embodiment. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. 1 is a cross-sectional view of an electrolysis cell. [Figure 5] FIG. 3 is a side view of the stack group as seen from the direction of arrow V in FIG. 2. [Figure 6] FIG. 3 is a front view of the stack group as seen from the direction of arrow VI in FIG. 2. [Figure 7] FIG. 10 is a perspective view of a stack group of hot modules in a second embodiment. [Figure 8] FIG. 8 is a side view of the stack group as seen from the direction of arrow VIII in FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0013] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. FIG. 1 is a block diagram of a hot module 10 in a first embodiment. The hot module 10 is a device that electrolyzes fuel gases such as steam and carbon dioxide to produce energy carriers such as hydrogen and hydrocarbons. Hot modules 10 include those that are capable of reversible operation between producing energy carriers and operating as a fuel cell that generates electricity from the energy carriers. In this embodiment, a hot module 10 that electrolyzes steam to produce hydrogen is illustrated.

[0014] The hot module 10 includes a stack group 11 that performs electrolysis, a vaporizer 12 that generates steam that is supplied to the cathode chamber 51 of the stack group 11, a heat exchanger 13 that exchanges heat between the gas supplied to the stack group 11 and the gas generated by the stack group 11, and a heater 14 that heats the stack group 11. To reduce heat radiation, the hot module 10 has the stack group 11, the vaporizer 12, the heat exchanger 13, and the heater 14 arranged inside a thermal insulation material 15. Heat-resistant fibers such as ceramic wool, RCF, and AES fill the gaps between the stack group 11, the vaporizer 12, the heat exchanger 13, and the heater 14.

[0015] The vaporizer 12 includes a heat exchanger that exchanges heat with the high-temperature gas containing oxygen produced by the stack group 11, and heats water to produce steam. The steam produced by the vaporizer 12 contains hydrogen, which reduces oxidation of the catalyst contained in the cathode 47 (see Figure 4). The hydrogen-containing steam exchanges heat with the hydrogen and oxygen produced by the stack group 11 in the heat exchanger 13, is heated to the operating temperature of the stack group 11 by the heater 14, and is supplied to the cathode chamber 51 of the stack group 11. The air exchanges heat with the hydrogen and oxygen produced by the stack group 11 in the heat exchanger 13, is heated to the operating temperature of the stack group 11 by the heater 14, and is supplied to the anode chamber 53 of the stack group 11. The condenser 16 is a device that cools the hydrogen gas, and the liquefied water is supplied to the vaporizer 12 as raw water.

[0016] 2 is a perspective view of the stack group 11. The stack group 11 includes stacks 17, 18, 19, and 20 installed on a rack (not shown). In this embodiment, the stack group 11 will be described as having four stacks arranged in a row, but the number of stacks is not limited to this, and can be set appropriately depending on the required amount of energy carriers to be generated.

[0017] Each of the stacks 17, 18, 19, and 20 has an anode terminal 21 and a cathode terminal 23. The stacks 17, 18, 19, and 20 are arranged spaced apart from one another with the surfaces on which the terminals 21 and 23 are provided facing the same direction. The stack 18 is arranged next to the stack 17, with the terminals 21 and 23 of the stack 18 facing the stack 17. The stack 20 is arranged next to the stack 19, with the terminals 21 and 23 of the stack 20 facing the stack 19. The stack 20 is arranged below the stack 18, and the stack 19 is arranged below the stack 17. A positive electrode of a power supply is connected to a connection portion 22 of the terminal 21 of the stack 17, and a negative electrode of the power supply is connected to a connection portion 24 of the terminal 23 of the stack 20.

[0018] Electric wire 25 connects connection portion 24 of terminal 23 of stack 17 to connection portion 22 of terminal 21 of stack 18. Electric wire 26 connects connection portion 24 of terminal 23 of stack 18 to connection portion 22 of terminal 21 of stack 19. Electric wire 27 connects connection portion 24 of terminal 23 of stack 19 to connection portion 22 of terminal 21 of stack 20. Electric wires 25, 26, and 27 connect stacks 17, 18, 19, and 20 in series.

[0019] 3 is a perspective view of stack 17. Stacks 17, 18, 19, and 20 have the same structure although they are installed at different positions on the rack. Therefore, the structure of stack 17 will be described below, and descriptions of the structures of stacks 18, 19, and 20 will be omitted. Stack 17 includes a stack 29 in which reaction units 28 are stacked in the thickness direction, conductors 30 and 31 arranged on both sides of the reaction units 28 in the stacking direction and electrically connected to stack 29, and end plates 32 and 33 that sandwich stack 29 and conductors 30 and 31 in the thickness direction. Stack 29 is made by stacking, for example, approximately 10 to 30 reaction units 28.

[0020] A terminal 21 is provided on the conductor 30, and a terminal 23 is provided on the conductor 31. The conductors 30, 31 and the terminals 21, 23 may be made of stainless steel, for example. An insulator 34 is disposed between the end plate 32 and the conductor 30, and an insulator 35 is disposed between the end plate 33 and the conductor 31.

[0021] Bolts 36 are arranged at the four corners of the periphery of the stack 17, penetrating the laminate 29, the conductors 30, 31, the insulators 34, 35, and the end plates 32, 33 in the thickness direction. The laminate 29, the conductors 30, 31, the insulators 34, 35, and the end plates 32, 33 are fastened together by the bolts 36.

[0022] Four spaces penetrating the periphery of the stack 17 in the thickness direction function as a passage 37a through which gas enters a cathode chamber 51 (described later) of a reaction unit 28 from outside the stack 17, a passage 37b through which gas exits from the cathode chamber 51 to outside the stack 17, a passage 38b through which gas enters an anode chamber 53 (described later) of a reaction unit 28 from outside the stack 17, and a passage 38a through which gas exits from the anode chamber 53 to outside the stack 17. The stack 17 fastened with bolts 36 includes side surfaces 39 extending in the stacking direction of the reaction units 28 and end surfaces 40 located at both ends of the stacking direction of the reaction units 28.

[0023] Figure 4 is an exploded view of the stack 17 taken along line IV-IV in Figure 3, passing through passages 37a and 37b. Figure 4 is a cross-sectional view taken along line IV-IV, with the components constituting one reaction unit 28 separated in the thickness direction. The thickness of each part is exaggerated in Figure 4. The reaction unit 28 includes, in order in the thickness direction, an interconnector 41, a cathode frame 42, a cell 43 with separators, and an anode frame 44.

[0024] The separator-equipped cell 43 includes an electrolytic cell 45 and a separator 49 disposed in an electrolyte 46 of the electrolytic cell 45. Holes (passages 37a, 37b) penetrate the interconnector 41, the cathode frame 42, the separator 49, and the anode frame 44.

[0025] The electrolytic cell 45 includes an electrolyte 46, and a cathode 47 and an anode 48 separated by the electrolyte 46. The material of the electrolyte 46 is a solid oxide, and examples thereof include stabilized zirconia, a ceria-based solid solution, and 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 the ceria-based solid solution include Gd, Sm, and Y.

[0026] Examples of the material for the cathode 47 include a material containing a catalyst containing Ni and zirconia with Y dissolved therein, and a material containing a catalyst containing Ni and ceria with Gd dissolved therein. Examples of the catalyst include Ni, Ni-based alloys, and cermet, which is a composite (sintered body) of NiO and an oxide (solid electrolyte).

[0027] The material of the anode 48 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.

[0028] The separator 49 is a frame-shaped member provided with an opening larger than the anode 48. The separator 49 is made of, for example, stainless steel. The separator 49 is airtightly joined to the electrolyte 46 with brazing material or the like, avoiding the anode 48.

[0029] The interconnectors 41 are conductive plate-like members arranged on both sides in the thickness direction of the electrolytic cell 45. The interconnectors 41 electrically connect the reaction units 28 adjacent to each other in the thickness direction. An example of the material of the interconnectors 41 is stainless steel.

[0030] The cathode frame 42 is a rectangular frame-shaped member disposed between the interconnector 41 and the separator 49. The cathode frame 42 is made of, for example, stainless steel. The cathode frame 42 surrounds the electrolytic cell 45 and a current collector 50 provided in the center of the interconnector 41.

[0031] The current collector 50 electrically connects the cathode 47 and the interconnector 41. The material of the current collector 50 is, for example, a porous body made of a gas-permeable metal such as Ni. A cathode chamber 51 surrounded by the interconnector 41 and the separator-equipped cell 43 is provided inside the cathode frame 42.

[0032] The anode frame 44 is a frame-shaped member disposed between the interconnector 41 and the separator 49. The material of the anode frame 44 is, for example, an insulator such as mica. The anode frame 44 surrounds a current collector 52 provided in the center of the interconnector 41. The current collector 52 electrically connects the anode 48 and the interconnector 41. In this embodiment, the current collector 52 is formed integrally with the interconnector 41, but this is not limitative. It is of course possible for the current collector 52 to be a member separate from the interconnector 41.

[0033] An anode chamber 53 surrounded by an interconnector 41 and a separator-equipped cell 43 is provided inside the anode frame 44. A separator 49 separates the cathode chamber 51 from the anode chamber 53, preventing the fuel gas in the cathode chamber 51 from mixing with the oxidizer gas (oxygen, air, etc.) in the anode chamber 53. Examples of fuel gas include water vapor, carbon dioxide, and a mixture thereof.

[0034] Returning to Figure 3, an interconnector 41 that contacts an anode chamber 53 (see Figure 4) contacts a conductor 30 provided with terminal 21, and an interconnector 41 that contacts a cathode chamber 51 contacts a conductor 31 provided with terminal 23. Terminals 21 and 23 protrude from one of four side surfaces 39 of stack 17, which has a substantially rectangular parallelepiped shape.

[0035] Pipes (not shown) through which gas flows are connected to the passages 37a, 37b, 38a, and 38b, respectively. The fuel gas that enters the passage 37a from the pipe passes through the cathode chambers 51 (see FIG. 4) provided in the respective reaction units 28, and then passes through passage 37b to exit the stack 17. The oxidant gas that enters the passage 38b from the pipe passes through the anode chambers 53 provided in the respective reaction units 28, and then passes through passage 38a to exit the stack 17.

[0036] When the positive electrode of the power supply is connected to terminal 21 and the negative electrode of the power supply is connected to terminal 23, electrons flow toward the cathode 47 of the electrolytic cell 45 (see FIG. 4). The fuel gas that enters the cathode chamber 51 is reduced at the cathode 47. Because electrons are taken away at the anode 48 of the electrolytic cell 45, oxide ions that have moved to the anode 48 via the electrolyte 46 are oxidized at the anode 48. As a result, energy carriers such as hydrogen and hydrocarbons are synthesized in the electrolytic cell 45.

[0037] 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 45 (the temperature of the exhaust gas flowing through the passages 37b and 38a) decreases as the current density increases, compared to the temperature at the open circuit voltage of the electrolytic cell 45 when current begins to flow (the average voltage of the electrolytic cell 45 when the current density is 0). As the current density increases further, the temperature of the electrolytic cell 45 begins to rise due to Joule heat, and the temperature reaches a thermal neutral point where endothermic and exothermic reactions are balanced. When the current density of the reaction unit 28 becomes lower than the current density of the reaction unit 28 at the thermal neutral point, endothermic reaction in the reaction unit 28 becomes dominant, and the temperature decreases. When the current density of the reaction unit 28 becomes higher than the current density of the reaction unit 28 at the thermal neutral point, exothermic reaction in the reaction unit 28 becomes dominant, and the temperature increases.

[0038] FIG. 5 is a side view of the stack group 11. The stack group 11 is heated from the surroundings by a heat source such as a heat exchanger 13 (see FIG. 1) so that the reaction units 28 (see FIG. 3) of the stacks 17, 18, 19, and 20 reach their operating temperatures. Of the two end faces 40 of the stacks 17, 18, 19, and 20, the face farthest from the heat source is less likely to heat and therefore its temperature is less likely to rise. Since the higher the temperature of the electrolytic cell 45, the more active the synthesis of energy carriers, it is preferable to reduce the occurrence of low-temperature portions of the stacks 17, 18, 19, and 20 and reduce temperature unevenness in the stacks 17, 18, 19, and 20 in order to activate the synthesis of energy carriers.

[0039] The stacks 17 and 19 are arranged side by side, with the end face 40 of the stack 17 closest to the terminal 23 facing the end face 40 of the stack 18 closest to the terminal 21. The stacks 18 and 20 are arranged side by side, with the end face 40 of the stack 18 closest to the terminal 23 facing the end face 40 of the stack 20 closest to the terminal 21. Portions of the electric wires 25 and 26 are arranged between the end face 40 of the stack 17 and the end face 40 of the stack 19, and portions of the electric wire 27 are arranged near the end face 40 of the stack 19.

[0040] The stack group 11 includes a proximity portion 54 where the end face 40 of the stack 17 and a portion of the electric wire 25 are located close to each other. In the proximity portion 54, a distance D2 between the electric wire 25 and the end face 40 is shorter than a distance D1 between the end face 40 and the connection portion 23 located closest to the proximity portion 54. The origin of the distances D1 and D2 on the end face 40 is a point 55 obtained by projecting the center of gravity of the conductor 31 (see FIG. 3 ) on which the connection portion 23 is provided onto the end face 40 along the stacking direction of the electrolytic cell 45 (see FIG. 4 ). The reason for using point 55 as the origin of the distances D1 and D2 is that the vicinity of point 55 (the center of the end face 40) is less likely to be heated by the atmosphere than the vicinity of the edge of the end face 40. Joule heat from the electric wire 25 in the proximity portion 54 is transferred to the end face 40 of the stack 17, heating the end face 40 of the stack 17. This reduces the occurrence of low-temperature portions of the stack 17 that are shaded by a heat source.

[0041] At the proximity portion 54, the electric wire 25 may be in contact with the end face 40 of the stack 17, or the electric wire 25 may be spaced apart from the end face 40. Because the electric wire 25 is covered with an insulating coating, problems such as a short circuit can be prevented even if the electric wire 25 is in contact with the stack 17.

[0042] It is preferable that the electrical resistance per unit length of the proximal portion 54 of the electric wire 25 is equal to or greater than the electrical resistance per unit length of the portions other than the proximal portion 54, because this allows for greater Joule heat of the electric wire 25 in the proximal portion 54. Examples of means for increasing the electrical resistance per unit length of the electric wire 25 include making the proximal portion 54 of the electric wire 25 thinner than the portions other than the proximal portion 54 of the electric wire 25, and disposing in the proximal portion 54 a material whose resistivity is higher than the portions other than the proximal portion 54 of the electric wire 25.

[0043] The stack group 11 includes a proximity portion 56 where the end face 40 of the stack 19 and a portion of the electric wire 26 are located close to each other. The proximity portion 56 is a portion where the distance D2 between the electric wire 26 and the end face 40 is shorter than the distance D1 between the end face 40 and the connection portion 22 located closest to the proximity portion 56. The origin of the distances D1 and D2 on the end face 40 is a point 57 obtained by projecting the center of gravity of the conductor 30 (see FIG. 3 ) on which the connection portion 22 is provided onto the end face 40 along the stacking direction of the electrolytic cell 45 (see FIG. 4 ). Joule heat from the electric wire 26 in the proximity portion 56 is transferred to the end face 40 of the stack 19, heating the end face 40 of the stack 19, thereby reducing the occurrence of low-temperature portions of the stack 19 that are caused by being shaded by a heat source.

[0044] The stack group 11 includes a proximity portion 58 where the end surface 40 of the stack 19 and a part of the electric wire 27 are located close to each other. Joule heat of the electric wire 27 in the proximity portion 58 is transferred to the end surface 40 of the stack 19, heating the end surface 40 of the stack 19, thereby reducing the occurrence of low-temperature portions of the stack 19 that are caused by being in the shadow of the heat source.

[0045] The stack group 11 has proximity portions 54, 56 at the portions where the end face 40 of the stack 17 and the end face 40 of the stack 19 face each other, so that it is possible to heat the end faces of the stacks 17, 19 that are sandwiched between the stacks 17, 19 and are likely to be in the shadow of the heat source. This further reduces the occurrence of low-temperature portions of the stacks 17, 19.

[0046] Because the stacks 17, 18, 19, and 20 are arranged with the surfaces on which the terminals 21 and 23 are provided facing the same direction, the electric wires 25, 26, and 27 connecting the stacks 17, 18, 19, and 20 can be longer than when the stacks 17, 18, 19, and 20 are arranged with the surfaces on which the terminals 21 and 23 are provided facing each other. Since the Joule heat of the electric wires 25, 26, and 27 can be increased, the heating effect of the stacks 17 and 18 by the adjacent portions 54, 56, and 58 can be increased.

[0047] 6 is a front view of the stack group 11 as viewed in the direction of arrow VI in FIG. 2. Stack 18 is hidden behind stack 17, and stack 20 is hidden behind stack 19. In stacks 17, 18, 19, and 20, the connection portion 22 of terminal 21 and the connection portion 24 of terminal 23 are arranged on opposite sides of an imaginary plane P that includes the arrangement direction of stacks 17, 18, 19, and 20 (the direction perpendicular to the paper surface in FIG. 6) and the stacking direction of electrolysis cells 45 (see FIG. 4) (the up-and-down direction in FIG. 6). Compared to when the connection portions 22 and 24 are arranged on plane P, the electric wire 25 connecting the terminal 23 of stack 17 to the terminal 21 of stack 18 can be made longer, the electric wire 26 connecting the terminal 21 of stack 18 to the terminal 21 of stack 19 can be made longer, and the electric wire 27 connecting the terminal 23 of stack 19 to the terminal 21 of stack 20 can be made longer. As a result, the Joule heat of the electric wires 25, 26, and 27 can be increased. Therefore, the effect of heating the stacks 17 and 18 by the adjacent portions 54, 56, and 58 can be increased.

[0048] A second embodiment will be described with reference to Figures 7 and 8. In the first embodiment, the stacks 17, 18, 19, and 20 are arranged with the surfaces on which the terminals 21 and 23 are provided facing the same direction. In contrast, in the second embodiment, the stacks 17, 18, 19, and 20 are arranged with the surfaces on which the terminals 21 and 23 are provided facing opposite directions. The same parts as those described in the first embodiment are given the same reference numerals, and the following description will be omitted.

[0049] 7 is a perspective view of a stack group 60 of a hot module 10 in the second embodiment. The stack group 60 includes stacks 17, 18, 19, and 20 installed in a rack (not shown). In this embodiment, as an example, the stack group 60 will be described in which four stacks are arranged, but the number of stacks is not limited to this, and can be set appropriately depending on the required amount of energy carriers to be generated.

[0050] Terminals 21 and 23 are arranged on stacks 17, 18, 19, and 20 facing opposite directions. A positive pole of a power supply is connected to connection portion 22 of terminal 21 of stack 17, and a negative pole of the power supply is connected to connection portion 24 of terminal 23 of stack 20. Electric wire 61 connects connection portion 24 of terminal 23 of stack 17 to connection portion 22 of terminal 21 of stack 18. Electric wire 62 connects connection portion 24 of terminal 23 of stack 18 to connection portion 22 of terminal 21 of stack 19. Electric wire 63 connects connection portion 24 of terminal 23 of stack 19 to connection portion 22 of terminal 21 of stack 20. Electric wires 61, 62, and 63 connect stacks 17, 18, 19, and 20 in series.

[0051] Fig. 8 is a side view of the stack group 60 as seen in the direction of arrow VIII in Fig. 7. The stack group 60 includes a proximity portion 64 between the end face 40 of the stack 17 and the electric wire 61. In the proximity portion 64, the distance between the electric wire 61 and the end face 40 of the stack 17 is shorter than the distance between the connection portion 24 located closest to the proximity portion 64 and the end face 40 of the stack 17. The proximity portion 64 heats the end face 40 of the stack 17.

[0052] The stack group 60 includes a proximity portion 65 between the end face 40 of the stack 18 and the electrical wire 61. In the proximity portion 65, the distance between the electrical wire 61 and the end face 40 of the stack 18 is shorter than the distance between the connection portion 24 located closest to the proximity portion 65 and the end face 40 of the stack 18. The proximity portion 65 heats the end face 40 of the stack 18.

[0053] The stack group 60 includes a proximity portion 66 between the end face 40 of the stack 19 and the electrical wire 62. In the proximity portion 66, the distance between the electrical wire 62 and the end face 40 of the stack 19 is shorter than the distance between the connection portion 22 located closest to the proximity portion 66 and the end face 40 of the stack 19. The proximity portion 66 heats the end face 40 of the stack 19.

[0054] The stack group 60 includes a proximity portion 67 between the end face 40 of the stack 20 and the electric wire 62. In the proximity portion 67, the distance between the electric wire 62 and the end face 40 of the stack 20 is shorter than the distance between the connection portion 22 located closest to the proximity portion 67 and the end face 40 of the stack 20. The proximity portion 67 heats the end face 40 of the stack 20.

[0055] The stack group 60 includes a proximity portion 68 between the end face 40 of the stack 19 and the electrical wire 63. In the proximity portion 68, the distance between the electrical wire 63 and the end face 40 of the stack 19 is shorter than the distance between the connection portion 24 located closest to the proximity portion 68 and the end face 40 of the stack 19. The proximity portion 68 heats the end face 40 of the stack 19.

[0056] The stack group 60 includes a proximity portion 69 between the end face 40 of the stack 20 and the electric wire 63. In the proximity portion 69, the distance between the electric wire 63 and the end face 40 of the stack 20 is shorter than the distance between the connection portion 24 located closest to the proximity portion 69 and the end face 40 of the stack 20. The proximity portion 69 heats the end face 40 of the stack 20.

[0057] Since the connection portions 22 and 24 of the stacks 17, 18, 19, and 20 are arranged facing opposite directions, the electric wires 61, 62, and 63 can be made longer than when the connection portions 22 and 24 are arranged facing the same direction. Since the Joule heat of the electric wires 61, 62, and 63 can be increased, the heating effect of the adjacent portions 64, 65, 66, 67, 68, and 69 on the stacks 17, 18, 19, and 20 can be increased.

[0058] Since the connection portions 22 and 24 of the stacks 17, 18, 19, and 20 are arranged facing opposite directions, it is possible to provide a proximity portion 65 that heats the end surface 40 of the stack 18 and proximity portions 67 and 69 that heat the end surface 40 of the stack 20. This makes it possible to reduce temperature variations in the stacks 18 and 20.

[0059] 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.

[0060] The electric wires 25, 26, 27, 61, 62, and 63 described in the embodiments may be flexible wires or may be hard wires (conductive plates) with a predetermined shape.

[0061] In the embodiment, the terminals 21, 23 are provided on one of the side surfaces 39 (four surfaces) of the stacks 17, 18, 19, 20, but this is not necessarily limited to this. Of course, it is possible to provide the terminal 21 on one of the side surfaces 39 (four surfaces) and the terminal 23 on another surface. It is also possible to arrange the terminals 21, 23 so that they are on the same straight line extending in the stacking direction of the electrolytic cell 45.

[0062] In the first embodiment, the case where the proximity portion 54 is provided between the stack 17 and the electric wire 25 and the proximity portion 56 is provided between the stack 19 and the electric wire 26 has been described, but this is not necessarily limited to this. It is of course possible to provide the proximity portion 54 between the stack 17 and the electric wire 26 and the proximity portion 56 between the stack 19 and the electric wire 25.

[0063] In the second embodiment, a case has been described in which the proximity portion 64 is provided between the stack 17 and the electric wire 61, and the proximity portion 65 is provided between the stack 18 and the electric wire 61, but this is not necessarily limited to this. It is of course possible to provide the proximity portion 64 between the stack 17 and the electric wire 62, or to provide the proximity portion 65 between the stack 18 and the electric wire 62.

[0064] In the second embodiment, a case has been described in which the proximity portion 66 is provided between the stack 19 and the electric wire 62, and the proximity portion 67 is provided between the stack 20 and the electric wire 62, but this is not necessarily limited to this. It is of course possible to provide the proximity portion 66 between the stack 19 and the electric wire 61, or to provide the proximity portion 67 between the stack 20 and the electric wire 61.

[0065] In the above embodiment, the stacks 17, 18, 19, and 20 have a flat cell design. The flat stacks 17, 18, 19, and 20 may be electrode-supported or electrolyte-supported. They may also be metal-supported (metal-supported flat-plate) stacks in which the cathode, anode, and electrolyte are supported by a porous metal such as an Fe-Cr-based metal.

[0066] In the embodiment, the electrolytic cell 45 has a rectangular shape, but this is not necessarily limited to this. The shape of the electrolytic cell 45 may be circular or elliptical, or may be polygonal other than a rectangular shape, such as a triangle or pentagon.

[0067] In the embodiment, the case where the electrolyte 46 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 46 that has proton conductivity under the operating conditions of the electrolytic cell 45. Examples of substances that exhibit proton conductivity under the operating conditions of the electrolytic cell 45 include perovskite-type oxides such as SrZrO3 and BaZrO3, in which the B site is substituted with a trivalent metal ion such as Y or In, pyrochlore-type oxides, and phosphates.

[0068] In the above embodiment, the gas passages 37a, 37b, 38a, and 38b are built into the stacks 17, 18, 19, and 20, but this is not necessarily limited to this. It is of course possible to connect manifolds serving as the gas passages 37a, 37b, 38a, and 38b to the electrolysis cell and provide them outside the electrolysis cell. Examples of materials for the manifolds include ceramics with high high-temperature strength.

[0069] In the embodiment, the conductors 30 and 31 provided with the terminals 21 and 23 are arranged in the stacks 17, 18, 19, and 20, but this is not necessarily limited to this. It is of course possible to omit the conductors 30 and 31 and the insulators 34 and 35, electrically connect the reaction units 28 to the end plates 32 and 33, and use the end plates 32 and 33 as terminals for the stacks 17, 18, 19, and 20. [Explanation of symbols]

[0070] 10 Hot Modules 17,18,19,20 stacks 21 terminals 22 Connection 23 terminals 24 Connection 25,26,27,61,62,63 Electric wire 29 Laminate 40 End face 45 Electrolysis Cell 46 Electrolytes 47 Cathode 48 Anode 54, 56, 58, 64, 65, 66, 67, 68, 69 Proximal area D1,D2 distance P plane

Claims

1. a stack of electrolytic cells each containing an electrolyte separating an anode from a cathode, the electrolytic cells being stacked and connected in series; a stack including two terminals of opposite polarities arranged on both sides of the electrolysis cell in the stacking direction of the stack and connected in series to the electrolysis cell; and an electric wire connected to the connection portion of the terminal and connecting a plurality of the stacks in series, a proximity portion where at least one of two end surfaces of the stack located at both ends in the stacking direction of the electrolysis cell and a part of the electric wire are located close to each other; A hot module in which the distance between the electric wire and the end face in the proximity portion is shorter than the distance between the connection portion located closest to the proximity portion and the end face in the proximity portion.

2. the stacks are arranged along a stacking direction of the electrolysis cells, The hot module according to claim 1 , wherein the adjacent portion is provided between the stacks adjacent to each other in the stacking direction of the electrolysis cells.

3. The stacks are arranged in a direction intersecting the stacking direction of the electrolysis cells, the stack has the connection portions disposed on opposite sides with respect to a virtual plane including a direction in which the stacks are arranged and a stacking direction of the electrolysis cells, The hot module according to claim 1 , wherein the adjacent portion includes a portion of the electric wire connected to the connection portion of the stack.

4. The stacks are arranged in a direction intersecting the stacking direction of the electrolysis cells, The stack is arranged with the connection portions facing in opposite directions, The hot module according to claim 1 , wherein the adjacent portion includes a portion of the electric wire connected to the connection portion of the stack.

5. 5. The hot module according to claim 1, wherein the electrical resistance per unit length of the adjacent portion of the electric wire is equal to or greater than the electrical resistance per unit length of the portion other than the adjacent portion.

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