JP2025076541A - Electrolysis module and electrolysis device - Google Patents

Abstract

To provide an electrolytic module and an electrolytic device which are capable of reducing heat dissipation from electrolytic cells.SOLUTION: An electrolysis module includes arrayed electrolytic cells, each containing elements that include an electrolyte isolating two electrodes, and the elements are electrically connected in series. When the electrolytic cells are divided into a peripheral portion on an outer periphery of the group of the arrayed electrolytic cells, and a central portion surrounded by the peripheral portion, an average of the area of the elements included in the electrolytic cells in the peripheral portion is greater than an average of the area of the elements included in the electrolytic cells in the central portion.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electrolysis module and an electrolysis device in which electrolysis cells are arranged.

An electrolysis module, which is an array of electrolysis cells in which an element part containing an electrolyte is arranged to separate two electrodes, electrolyzes fuel gas in the element part heated to an operating temperature, synthesizing energy carriers such as hydrogen and hydrocarbons (Patent Document 1).

JP 2023-72892 A

In order to reduce the energy required to heat the element to its operating temperature, technology is required to reduce heat dissipation from the electrolytic cell.

The present invention has been made to meet this demand, and aims to provide an electrolysis module and electrolysis device that can reduce heat dissipation from the electrolysis cell.

The first aspect for achieving this object is an electrolysis module including an electrolysis cell in which an element part containing an electrolyte is arranged to separate two electrodes, the electrolysis cells being arranged and the element parts being electrically connected in series, in which when the electrolysis cell is partitioned into an outer peripheral part located on the outer periphery of the set of arranged electrolysis cells and a central part surrounded by the outer peripheral part, the average area of the element parts included in the electrolysis cells in the outer peripheral part is larger than the average area of the element parts included in the electrolysis cells in the central part.

In the second aspect, the average area of the element parts included in the electrolytic cell in the central portion is 40% or more of the average area of the element parts included in the electrolytic cell in the peripheral portion in the first aspect.

In the third aspect, in the first or second aspect, the average area of the element parts included in the electrolytic cell in the central portion is 97% or less of the average area of the element parts included in the electrolytic cell in the peripheral portion.

The fourth aspect includes an electrolysis module according to any one of the first to third aspects, a power source that passes a current through a circuit connected to the electrodes, and an adjustment unit that adjusts the output of the power source, and the adjustment unit sets the average voltage of the central portion to a voltage higher than the thermal neutral point where the heat absorption and heat generation are balanced in the electrolysis module set to a predetermined temperature, and sets the average voltage of the outer periphery to a voltage lower than the thermal neutral point.

According to the present invention, when the electrolytic cell is divided into an outer periphery located on the outer periphery of the set of arranged electrolytic cells and a central portion surrounded by the outer periphery, the average area of the element parts included in the electrolytic cells in the outer periphery is larger than the average area of the element parts included in the electrolytic cells in the central portion. Since the element parts are connected in series, the same current flows in the outer periphery and the central portion, and the current density of the element parts in the outer periphery can be made smaller than the current density of the element parts in the central portion. By reducing the temperature rise in the outer periphery, which dissipates more heat than the central portion, and by reducing the difference between the temperature of the outer periphery and the temperature of the atmosphere, the heat dissipation of the electrolytic cell can be reduced.

FIG. 2 is a perspective view of an electrolysis module according to the first embodiment. FIG. 2 is a cross-sectional view of an electrolysis cell. 1 is a graph showing the current-voltage characteristics and heat generation characteristics of an electrolysis module. FIG. 2 is a plan view of the electrolysis module. FIG. 1 is a block diagram of an electrolysis device. FIG. 11 is a plan view of an electrolysis module according to a second embodiment. FIG. 1 is a perspective view of an electrolysis cell. FIG. 13 is a side view of the electrolysis module according to the third embodiment. FIG. 9 is a cross-sectional view of the electrolysis module taken along line IX-IX in FIG. 8. FIG. 13 is a perspective view of an electrolysis module according to a fourth embodiment. FIG. 2 is an exploded view of the electrolysis cell.

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. FIG. 1 is a perspective view of an electrolysis module 10 in a first embodiment. The electrolysis module 10 includes a plurality of electrolysis cells 11. The electrolysis cells 11 have element sections 13 arranged on a breathable support 12. The electrolysis module 10 includes a manifold 14 connected to one end of the support 12, and a manifold 15 connected to the other end of the support 12. The electrolysis cells 11 are arranged between the manifolds 14 and 15. In this embodiment, 20 electrolysis cells 11 are arranged at intervals from each other in three rows.

Figure 2 is a cross-sectional view of the electrolysis cell 11. The support 12 has a plurality of cavities 16 with a circular cross section that connect the manifolds 14 and 15. The element units 13 are provided on the outer surfaces (front and back) of the support 12. The support 12 has air permeability between the outer surface of the support 12 and the cavities 16. The element units 13 include, in order from the outer surface of the support 12, a fuel electrode 17, an electrolyte 18, and an air electrode 19. In Figure 2, the thickness of the element units 13 is exaggerated. In this embodiment, the electrolysis cell 11 is a flat cylindrical horizontal stripe electrolysis cell in which the element units 13 are lined up along the cavities 16.

The support 12 is a member that does not have electronic conductivity, and an example of the material is stabilized zirconia. Examples of stabilizers for stabilized zirconia include CaO and MgO. Examples of the material for the fuel electrode include a material that includes a catalyst containing Ni and zirconia with Y dissolved therein, and a material that includes a catalyst containing Ni and ceria with Gd dissolved therein. Examples of the catalyst include Ni, Ni-based alloys, and cermets that are composites (sintered bodies) of NiO and oxides (solid electrolytes).

The material of the electrolyte 18 is a solid oxide, and examples thereof include stabilized zirconia, a ceria-based solid solution, and a solid solution of one or more selected from stabilized zirconia and a ceria-based solid solution and _alumina . Examples of stabilizers for stabilized zirconia include CaO, MgO, _Y2O3 , _Sc2O3 , and _{Yb2O3 .} Examples of elements that are dissolved in ceria in _the ceria-based solid solution include Gd, Sm, and Y.

Examples of the material of the air electrode 19 include perovskite oxides such as _{La1- xSrxMnO3 -δ} , _{La1-xSrxCoO3-δ, La1- xSrxCo1- YFeYO3 - δ , and Pr1 - xSrxMnO3 -δ} .

The interconnector 20 connects the air electrode 19 and fuel electrode 17 of adjacent element units 13. An example of the material of the interconnector 20 is conductive La1 _{- xSrxTiO3 -δ} . In one electrolysis cell 11, the element units 13 are connected in series by the interconnector 20. In adjacent electrolysis cells 11, the element units 13 are connected by a connecting member (not shown), and the element units 13 included in 60 electrolysis cells 11 are connected in series.

Returning to FIG. 1, the manifold 14 supplies fuel gas to each of the electrolytic cells 11. Examples of fuel gas include water vapor, carbon dioxide, and a mixture of these. The spent fuel gas that has passed through each of the electrolytic cells 11 is supplied to the manifold 15. An oxidizer gas flows outside the electrolytic cells 11. Examples of the oxidizer gas include air and oxygen.

When the positive electrode of a power source (not shown) is connected to the air electrode 19 (see FIG. 2) of the element section 13 and the negative electrode of the power source is connected to the fuel electrode 17, electrons flow toward the fuel electrode 17. The fuel gas that has passed through the support 12 is reduced at the fuel electrode 17. Since electrons are taken away at the air electrode 19, oxide ions that have moved to the air electrode 19 via the electrolyte 18 are oxidized at the air electrode 19. As a result, energy carriers such as hydrogen and hydrocarbons are synthesized in the electrolysis cell 11.

Figure 3 is a graph showing the current-voltage characteristics and heat generation characteristics of the electrolysis module 10. Since the electrolysis of water vapor, carbon dioxide, and other substances contained in the fuel gas is an endothermic reaction, the temperature of the element section 13 (the temperature of the exhaust gas entering the manifold 15) decreases as the current density increases, compared to the temperature at the open circuit voltage of the element section 13 when current begins to flow (the average voltage of the element section 13 when the current density is 0). If the current density increases further, the temperature of the element section 13 begins to rise due to Joule heat, and reaches the thermal neutral point N where the heat absorption and heat generation are balanced.

At the thermal neutral point N, the electrolytic cell 11 neither generates nor absorbs heat, but when the current density of the element part 13 becomes lower than the current density of the element part 13 at the thermal neutral point N, the electrolytic cell 11 becomes dominated by heat absorption, and the temperature drops. When the current density of the element part 13 becomes higher than the current density of the element part 13 at the thermal neutral point N, the electrolytic cell 11 becomes dominated by heat generation, and the temperature rises.

Returning to FIG. 1, the electrolysis module 10 is typically placed in an insulated container (not shown). The electrolysis module 10 is used in a state where the electrolysis cell 11 is heated by a heater (not shown) and the element unit 13 is at its operating temperature (e.g., about 700°C). Reducing the heat dissipation from the heated electrolysis cell 11 can reduce the energy required to heat the element unit 13 to its operating temperature, thereby improving the efficiency of energy carrier synthesis.

Figure 4 is a plan view of the electrolysis module 10. The manifolds 14, 15 are not shown in Figure 4. The outer peripheral portion 21 is a portion located on the outer periphery of the arranged electrolysis cells 11. In this embodiment, 42 electrolysis cells 11 are included in the outer peripheral portion 21. The central portion 22 is a portion surrounded by the outer peripheral portion 21. In this embodiment, 18 electrolysis cells 11 are included in the central portion 22. When the collection of electrolysis cells 11 is viewed in a plan view, a single ring is formed by connecting the electrolysis cells 11 included in the outer peripheral portion 21 with lines. The electrolysis cells 11 included in the central portion 22 are located inside the ring.

In the electrolysis module 10, the average area of the element parts 13 (see FIG. 1) included in the electrolysis cells 11 in the outer peripheral portion 21 is larger than the average area of the element parts 13 included in the electrolysis cells 11 in the central portion 22. The area of the element parts 13 refers to the area of the parts where the electrolyte 18 (see FIG. 2), the fuel electrode 17, and the air electrode 19 overlap. The area of the element parts 13 can be changed, for example, by changing the area of the fuel electrode 17 or the air electrode 19. The average area of the element parts 13 is the sum of the areas of the element parts 13 divided by the number of element parts 13 for which the sum was calculated.

The element parts 13 of the electrolytic cell 11 are electrically connected in series, so the same current flows through the element parts 13. The average area of the element parts 13 included in the electrolytic cell 11 in the outer periphery 21 is larger than the average area of the element parts 13 included in the electrolytic cell 11 in the central part 22, so the current density of the element parts 13 in the outer periphery 21 can be made smaller than the current density of the element parts 13 in the central part 22. This makes it possible to reduce the temperature rise of the element parts 13 in the outer periphery 21.

The central portion 22 is surrounded by the outer peripheral portion 21, and the outer peripheral portion 21 is open on the opposite side of the central portion 22, so that the heat dissipation of the outer peripheral portion 21 is greater than that of the central portion 22. Since the temperature rise of the outer peripheral portion 21, which dissipates more heat than the central portion 22, can be reduced, the difference between the temperature of the outer peripheral portion 21 and the temperature of the atmosphere can be reduced. This allows the electrolysis module 10 to reduce heat dissipation of the electrolysis cell 11 heated by a heater (not shown). Therefore, the energy required by the heater to heat the element portion 13 to the operating temperature can be reduced, and the efficiency of energy carrier synthesis can be improved.

It is preferable that the average area of the element parts 13 included in the electrolytic cell 11 in the central portion 22 is 40% or more of the average area of the element parts 13 included in the electrolytic cell 11 in the peripheral portion 21, since this prevents the current density of the element parts 13 in the central portion 22 from becoming excessive and reduces deterioration of the element parts 13 in the central portion 22. It is preferable that the average area of the element parts 13 included in the electrolytic cell 11 in the central portion 22 is 97% or less of the average area of the element parts 13 included in the electrolytic cell 11 in the peripheral portion 21, since this allows a difference to be made between the heat generation of the element parts 13 in the central portion 22 and the heat generation of the element parts 13 in the peripheral portion 21.

Figure 5 is a block diagram of the electrolysis device 30. The electrolysis device 30 includes an electrolysis module 10, a power supply 31 that supplies current to the element portion 13 of the electrolysis module 10, and an adjustment portion 33 that adjusts the output of the power supply 31. In Figure 5, the element portions 13 included in the electrolysis cells 11 in the outer peripheral portion 21 and central portion 22 of the electrolysis module 10 are represented by line segments. The length of the line segments indicates the average size of the area of the element portions 13 included in the electrolysis cells 11 in each portion.

An ammeter 32 that measures the current flowing through the circuit is disposed in the circuit connected to the power supply 31 and the element unit 13. The power supply 31 outputs a unipolar pulsating current, pulse, or direct current to the circuit.

The electrolysis device 30 is equipped with a thermometer 34 that detects the temperature of the electrolysis cell 11 (see FIG. 1). The thermometer 34 is placed near the manifold 15 and detects the temperature of the exhaust gas entering the manifold 15 as a representative value of the temperature of the electrolysis cell 11. However, this is not limited to this, and it is of course possible to place the thermometer 34 in a part other than the manifold 15 and detect a representative value of the temperature of the electrolysis cell 11.

The electrolysis device 30 is equipped with a heater (not shown) that heats the electrolysis cell 11. There are no limitations on the heater as long as it can heat the electrolysis cell 11. Examples of heaters include a heater that heats the fuel gas or oxidant gas supplied to the electrolysis cell 11 to heat the electrolysis cell 11, and a heater that is placed in an insulated container that houses the electrolysis cell 11 to heat the electrolysis cell 11 from around the electrolysis cell 11.

The adjustment unit 33 includes a CPU, ROM, RAM, and backup RAM (none of which are shown). The adjustment unit 33 obtains the current detected by the ammeter 32, and adjusts the output of the power source 31 so that the average temperature of the element unit 13 (the temperature of the electrolytic cell 11) becomes a temperature equivalent to the thermal neutral point N (see FIG. 3). Since the area of the element unit 13 is known, the current to be passed through the electrolytic cell 11 in order to make the average temperature of the element unit 13 a temperature equivalent to the thermal neutral point N is determined in advance. The adjustment unit 33 adjusts the output of the power source 31 so that the current detected by the ammeter 32 becomes equal to the previously determined current.

Instead of the adjustment unit 33 adjusting the output of the power supply 31 so that the current detected by the ammeter 32 is equal to the pre-determined current, the adjustment unit 33 may obtain the temperature detected by the thermometer 34 and adjust the output of the power supply 31 so that the average temperature of the element unit 13 (the temperature of the electrolytic cell 11) becomes a temperature equivalent to the thermal neutral point N. The adjustment unit 33 may use both of these.

In the electrolysis module 10, the average area of the element parts 13 included in the electrolysis cells 11 in the outer peripheral portion 21 is larger than the average area of the element parts 13 included in the electrolysis cells 11 in the central portion 22. Therefore, when a current flows through the electrolysis cells 11 so that the average temperature of the element parts 13 becomes a temperature equivalent to the thermal neutral point N, the average voltage of the element parts 13 included in the central portion 22 becomes higher than the voltage equivalent to the thermal neutral point N. In addition, the average voltage of the element parts 13 included in the outer peripheral portion 21 becomes lower than the voltage equivalent to the thermal neutral point N.

As a result, the average temperature of the element parts 13 included in the central part 22 becomes higher than the temperature corresponding to the thermal neutral point N, and the average temperature of the element parts 13 included in the peripheral part 21 becomes lower than the temperature corresponding to the thermal neutral point N. This makes it possible to make the activation overvoltage of the central part 22 lower than the activation overvoltage of the peripheral part 21. As a result, the central part 22 can synthesize energy carriers more efficiently than the peripheral part 21 for the energy input by the power source 31 to the electrolysis module 10.

Furthermore, since the average temperature of the element portion 13 included in the outer peripheral portion 21 is lower than the temperature corresponding to the thermal neutral point N, heat dissipation from the outer peripheral portion 21 can be reduced. Since the energy loss caused by the heater (not shown) in heating the element portion 13 to the operating temperature can be reduced, the efficiency of synthesizing energy carriers can be improved.

The electrolysis device 30 performs electrolysis near the current density of the element part 13 that corresponds to the thermal neutral point N, so the temperature of the element part 13 can be maintained even with little new energy input. This ensures electrolysis efficiency. Furthermore, the temperature change of the element part 13 can be reduced, improving the durability of the element part 13.

The electrolytic module 40 in the second embodiment will be described with reference to Figures 6 and 7. In the second embodiment, the electrolytic module 40 including cylindrical vertical stripe electrolytic cells 41 will be described. Figure 6 is a plan view of the electrolytic module 40 in the second embodiment. The electrolytic module 40 includes a plurality of electrolytic cells 41. In this embodiment, a total of 18 electrolytic cells 41 are arranged, six vertically and three horizontally.

Figure 7 is a perspective view of the electrolytic cell 41. The electrolytic cell 41 is cylindrical and includes an element section 42. From the inside to the outside, the element section 42 includes an air electrode 43, an electrolyte 44, and a fuel electrode 45. An interconnector 46 is connected to the air electrode 43. The materials of the air electrode 43, the electrolyte 44, the fuel electrode 45, and the interconnector 46 are the same as those of the air electrode 19, the electrolyte 18, the fuel electrode 17, and the interconnector 20 of the electrolytic cell 11 in the first embodiment, so a description thereof will be omitted.

Returning to FIG. 6, adjacent electrolytic cells 41 are connected by conductors 47. The conductors 47 are in contact with the interconnectors 46 and fuel electrodes 45 of adjacent electrolytic cells 41. The conductors 47 also function to buffer the thermal expansion of the electrolytic cells 41. An example of the conductors 47 is a nonwoven fabric of metal fibers containing nickel or the like.

The electrolytic cells 41 adjacent to each other in a different direction via the conductor 47 are electrically insulated by the insulator 48. Examples of materials for the insulator 48 include alumina, mullite, magnesia, and zirconia. All of the electrolytic cells 41 are connected in series by the conductors 47 and the insulators 48. With oxidant gas supplied into the electrolytic cells 41 and fuel gas supplied outside the electrolytic cells 41, electrolysis is carried out in the element section 42 to which a voltage is applied.

When the electrolysis module 40 is divided into two parts, an outer peripheral part 49 located on the outer periphery of the set of electrolysis cells 41, and a central part 50 surrounded by the outer peripheral part 49, the average area of the element part 42 included in the electrolysis cells 41 in the outer peripheral part 49 is larger than the average area of the element part 42 included in the electrolysis cells 41 in the central part 50. Since the current density of the element part 42 in the outer peripheral part 49 can be made smaller than the current density of the element part 42 in the central part 50, the temperature rise of the element part 42 in the outer peripheral part 49 can be reduced. Since the difference between the temperature of the outer peripheral part 49 and the temperature of the atmosphere can be reduced, the heat dissipation of the electrolysis cells 41 heated by a heater (not shown) can be reduced. Therefore, the energy required by the heater to heat the element part 42 to the operating temperature can be reduced, and the efficiency of synthesizing energy carriers can be improved.

The electrolysis module 60 in the third embodiment will be described with reference to Figures 8 and 9. In the third embodiment, the electrolysis module 60 including a cylindrical horizontal stripe electrolysis cell 61 will be described. Figure 8 is a side view of the electrolysis module 60 in the third embodiment. Figure 9 is a cross-sectional view of the electrolysis module 60 taken along line IX-IX in Figure 8.

In the electrolysis module 60, manifolds 63, 64 are connected to both ends of a plurality of cylindrical electrolysis cells 61 arranged at intervals from each other. The electrolysis cells 61 include a support and a plurality of element units 62 arranged on the support. The element units 62 include, in order from the outer surface of the support, a fuel electrode, an electrolyte, and an air electrode, and adjacent element units 62 are connected by an interconnector (all not shown). The support, fuel electrode, electrolyte, air electrode, and interconnector included in the electrolysis cell 61 are similar to the support 12, fuel electrode 17, electrolyte 18, air electrode 19, and interconnector 20 of the electrolysis cell 11 in the first embodiment, so a description thereof will be omitted. All element units 62 are connected in series.

The manifold 63 supplies fuel gas into the electrolytic cells 61. The spent fuel gas that has passed through each of the electrolytic cells 61 is supplied to the manifold 64. The oxidizer gas flows outside the electrolytic cells 61. Electrolysis takes place in the element section 62 to which a voltage is applied.

When the electrolytic cell 61 of the electrolytic module 60 is divided into two parts, an outer peripheral part 65 located on the outer periphery of the set of electrolytic cells 61, and a central part 66 surrounded by the outer peripheral part 65, the average area of the element parts 62 included in the electrolytic cell 61 in the outer peripheral part 65 is larger than the average area of the element parts 62 included in the electrolytic cell 61 in the central part 66. Since the current density of the element parts 62 in the outer peripheral part 65 can be made smaller than the current density of the element parts 62 in the central part 66, the temperature rise of the element parts 62 in the outer peripheral part 65 can be reduced, and heat dissipation can be reduced.

The electrolytic module 70 in the fourth embodiment will be described with reference to Figures 10 and 11. In the fourth embodiment, the electrolytic module 70 including a flat electrolytic cell 71 will be described. Figure 10 is a perspective view of the electrolytic module 70 in the fourth embodiment. In this embodiment, a total of nine electrolytic cells 71 are arranged, three vertically and three horizontally.

The electrolytic cell 71 includes a reaction unit 72 and end plates 73, 74 that sandwich the reaction unit 72 in the thickness direction. Bolts 75 are arranged on the periphery of the electrolytic cell 71, penetrating the reaction unit 72 and the end plates 73, 74 in the thickness direction. The reaction unit 72 and the end plates 73, 74 are fastened by the bolts 75. In this embodiment, multiple reaction units 72 are stacked on top of each other.

The four spaces that penetrate the periphery of the electrolytic cell 71 in the thickness direction function as a passage 76 through which gas enters from outside the electrolytic cell 71 to the fuel chamber 90 (described later) of the reaction unit 72, a passage 77 through which gas exits from the fuel chamber 90 to the outside of the electrolytic cell 71, a passage 78 through which gas enters from outside the electrolytic cell 71 to the air chamber 92 (described later) of the reaction unit 72, and a passage 79 through which gas exits from the air chamber 92 to the outside of the electrolytic cell 71.

Figure 11 is an exploded view of the electrolysis cell 71 cut along line XI-XI in Figure 10, passing through passages 76 and 77. Figure 11 is a cross-sectional view along line XI-XI, with the components constituting one reaction unit 72 separated in the thickness direction. In Figure 11, the thickness of each part is exaggerated. The reaction unit 72 includes, in order in the thickness direction, an interconnector 80, an anode frame 81, a cell with separator 82, and an cathode frame 83.

The separator-equipped cell 82 includes an element portion 84 and a separator 88 arranged in the element portion 84. Holes (passages 76-78) penetrate the interconnector 80, the fuel electrode frame 81, the separator 88, and the air electrode frame 83. The element portion 84 includes an electrolyte 85, and an anode 86 and an air electrode 87 isolated by the electrolyte 85. The materials of the electrolyte 85, the anode 86, and the air electrode 87 are the same as those of the electrolyte 18, the anode 17, and the air electrode 19 of the electrolysis cell 11 in the first embodiment, so a description thereof will be omitted.

The separator 88 is a frame-shaped member with an opening larger than the air electrode 87. The separator 88 is made of, for example, stainless steel. The separator 88 is hermetically bonded to the electrolyte 85 by brazing material or the like, avoiding the air electrode 87.

The interconnector 80 is a conductive plate-like member arranged on both sides of the element section 84 in the thickness direction. The interconnector 80 electrically connects adjacent reaction units 72 in the thickness direction. An example of the material of the interconnector 80 is stainless steel.

The fuel electrode frame 81 is a frame-shaped member disposed between the interconnector 80 and the separator 88. An example of the material of the fuel electrode frame 81 is stainless steel. The fuel electrode frame 81 surrounds the element portion 84 and the current collector 89 provided in the center of the interconnector 80.

The current collector 89 electrically connects the fuel electrode 86 and the interconnector 80. The material of the current collector 89 is, for example, a gas-permeable porous body made of a metal such as Ni. Inside the fuel electrode frame 81, a fuel chamber 90 is provided, surrounded by the interconnector 80 and the separator-equipped cell 82.

The air electrode frame 83 is a frame-shaped member disposed between the interconnector 80 and the separator 88. Examples of the material of the air electrode frame 83 include an insulator such as mica. The air electrode frame 83 surrounds a current collector 91 provided in the center of the interconnector 80. The current collector 91 electrically connects the air electrode 87 and the interconnector 80. In this embodiment, the current collector 91 is formed integrally with the interconnector 80, but this is not limited to this. It is of course possible for the current collector 91 to be a separate member from the interconnector 80.

An air chamber 92 surrounded by an interconnector 80 and a separator-equipped cell 82 is provided inside the air electrode frame 83. The separator 88 separates the fuel chamber 90 from the air chamber 92, preventing the fuel gas in the fuel chamber 90 from mixing with the oxidizer gas in the air chamber 92.

Returning to FIG. 10, the electrolytic cell 71 includes a terminal plate 93 arranged between the end plate 73 and the reaction unit 72, and a terminal plate 94 arranged between the end plate 74 and the reaction unit 72. The reaction units 72 are electrically connected in series between the terminal plates 93 and 94. The terminal plate 93 is connected to the air electrode 87, and the terminal plate 94 is connected to the fuel electrode 86. The protruding portions of the terminal plates 93 and 94 function as terminals. The terminal plate 94 has holes (passages 76-78) penetrating it. The element parts 84 included in the multiple electrolytic cells 71 are connected in series.

When the positive pole of a power supply (not shown) is connected to terminal plate 93 and the negative pole of the power supply is connected to terminal plate 94, electrons flow toward the fuel electrode 86 of element section 84. The fuel gas that enters the fuel chamber 90 is reduced at the fuel electrode 86. Since electrons are taken away from the air electrode 87 of element section 84, oxide ions that have moved to the air electrode 87 via electrolyte 85 are oxidized at the air electrode 87. As a result, energy carriers such as hydrogen and hydrocarbons are synthesized in the electrolysis cell 71.

When the electrolytic cell 71 of the electrolytic module 70 is divided into two parts, an outer peripheral part 95 (eight in this embodiment) located on the outer periphery of the set of electrolytic cells 71, and a central part 96 (one in this embodiment) surrounded by the outer peripheral part 95, the average area of the element part 84 included in the electrolytic cell 71 in the outer peripheral part 95 is larger than the average area of the element part 84 included in the electrolytic cell 71 in the central part 96. Since the current density of the element part 84 in the outer peripheral part 95 can be made smaller than the current density of the element part 84 in the central part 96, the temperature rise of the element part 84 in the outer peripheral part 95 can be reduced. Since the electrolytic module 70 can reduce the heat dissipation of the electrolytic cell 71 heated by a heater (not shown), the energy required by the heater to heat the element part 84 to the operating temperature can be reduced, and the efficiency of synthesizing energy carriers can be improved.

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

The number and arrangement of the electrolytic cells 11, 41, 61, and 71 in the embodiment are merely examples and are set appropriately according to the required characteristics of the electrolytic module.

In the first embodiment, an electrolysis module 10 in which multiple element units 13 are provided in one electrolysis cell 11 has been described, but this is not necessarily limited to this. Electrolysis cells 11 each having one element unit 13 may be mixed and arranged with electrolysis cells 11 each having multiple element units 13, or multiple electrolysis cells 11 each having one element unit 13 may be arranged.

In the first embodiment, the electrolytic cells 11 are arranged in a flat cylindrical horizontal stripe shape, but this is not necessarily limited to this. It is of course possible to change the design of the electrolytic cells 11 to a flat plate shape or a cylindrical horizontal stripe shape.

In the second embodiment, an electrolysis module 40 in which all 18 electrolysis cells 41 are connected in series has been described, but this is not necessarily limited to this. For example, it is of course possible to create two sets of nine cells, three vertical and three horizontal, connected in series, and connect the two sets in parallel. In this case, when the electrolysis cell 41 is divided into an outer periphery (eight cells) and a central portion (one cell) surrounded by the outer periphery, the average area of the element portion 42 included in the electrolysis cell 41 in the central portion is set to be smaller than the average area of the element portion 42 included in the electrolysis cell 41 in the outer periphery.

In the third embodiment, the electrolytic cells 61 are clustered together, but this is not necessarily limited to this. It is of course possible to arrange the electrolytic cells 61 vertically and horizontally or in a single horizontal row.

In the fourth embodiment, the electrolytic cell 71 is described as having a flat plate design. The flat plate electrolytic cell 71 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 electrodes and electrolyte are supported by a porous body of a metal such as an Fe-Cr system.

In the fourth embodiment, the passages 76-79 through which the gas passes are built into the electrolytic cell 71, but this is not necessarily limited to this. It is of course possible to connect a manifold serving as the passages 76-79 to the electrolytic cell and provide it outside the electrolytic cell. Examples of materials for the manifold include ceramics, which have high high-temperature strength.

In the fourth embodiment, the terminal plates 93, 94 including terminals to which a power source (not shown) is connected are arranged in the electrolytic cell 71, but this is not necessarily limited to this. It is of course possible to omit the terminal plates 93, 94 and electrically connect the reaction units 72 to the end plates 73, 74, thereby making the end plates 73, 74 the terminals of the electrolytic cell 71.

In the embodiment, the case where the element parts 13, 42, 62, 84 of the electrolytic cells 11, 41, 61, 71 included in the electrolytic module 10, 40, 60, 70 are all connected in series, that is, the case where there is only one circuit in which the element parts 13, 42, 62, 84 are connected in series in the electrolytic module 10, 40, 60, 70 is described, but this is not necessarily limited to this. Of course, it is possible for the electrolytic module 10, 40, 60, 70 to have multiple circuits in which the element parts 13, 42, 62, 84 are connected in series. In this case, the electrolytic cell including the element parts constituting the circuit connected in series is divided into an outer periphery and a center, and the average area of the element parts included in the electrolytic cell in the center is made smaller than the average area of the element parts included in the electrolytic cell in the outer periphery.

In the embodiment, the electrolyte 18, 44, 85 having oxide ion conductivity is used, but the present invention is not necessarily limited to this. It is of course possible to use the electrolyte 18, 44, 85 having proton conductivity under the operating conditions of the element unit 13, 42, 62, 84. Examples of materials that exhibit proton conductivity under the operating conditions of the element unit 13, 42, 62, 84 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.

10, 40, 60, 70 Electrolysis module 11, 41, 61, 71 Electrolysis cell 13, 42, 62, 84 Element portion 17, 45, 86 Fuel electrode (electrode)
18, 44, 85 Electrolyte 19, 43, 87 Air electrode
21, 49, 65, 95 outer peripheral part 22, 50, 66, 96 central part 30 electrolysis device 31 power supply 33 adjustment part

Claims (4)

An electrolysis module including an electrolysis cell in which an element portion including an electrolyte is disposed separating two electrodes, the electrolysis cells being arranged and the element portions being electrically connected in series,
An electrolysis module, wherein when the electrolysis cells are partitioned into an outer periphery located on the outer periphery of the set of arranged electrolysis cells and a central portion surrounded by the outer periphery, the average area of the element units included in the electrolysis cells in the outer periphery is larger than the average area of the element units included in the electrolysis cells in the central portion. The electrolytic module according to claim 1, wherein the average area of the element parts included in the electrolytic cell in the central part is 40% or more of the average area of the element parts included in the electrolytic cell in the peripheral part. The electrolytic module according to claim 1, wherein the average area of the element parts included in the electrolytic cell in the central part is 97% or less of the average area of the element parts included in the electrolytic cell in the peripheral part. An electrolysis module according to any one of claims 1 to 3;
A power source that applies a current to a circuit connected to the electrodes;
An adjustment unit that adjusts the output of the power source,
The adjustment unit sets an average voltage of the central portion to a voltage higher than a thermal neutral point at which heat absorption and heat generation are balanced in the electrolysis module, which is set to a predetermined temperature, and sets an average voltage of the outer periphery to a voltage lower than the thermal neutral point.

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