Annular packing material, electrochemical module, electrochemical device, energy system, solid oxide fuel cell and solid oxide electrolysis cell

Abstract

The present invention comprises a metal material 42a, 52a formed from a thermal expansion member that expands with heat, and an insulating metal oxide layer 42b, 52b. A through hole 42c, 52c is formed on the inside of the metal material 42a, 52a and metal oxide layer 42b, 52b formed in an annular shape.

Description

[Technical Field]

[0001] The present invention relates to an annular packing material that can be used in, for example, an electrochemical module, an electrochemical module including this annular packing material, an electrochemical device, an energy system, a solid oxide fuel cell, and a solid oxide electrolysis cell. [Background technology]

[0002] In a fuel cell stack, a stack is formed by stacking a plurality of electrochemical elements (power generation cells). A seal material is provided between the power generation cells to maintain a seal against reactant gases.

[0003] Known conventional sealing materials include, for example, those containing insulating materials such as vermiculite to block electronic conduction between power generation cells and prevent short circuits, as disclosed in Patent Document 1 below. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2016-511506 Summary of the Invention [Problem to be solved by the invention]

[0005] Fuel cell stacks typically reach temperatures of over 500°C during power generation, so sealing materials must have excellent heat resistance.

[0006] Although inorganic materials such as vermiculite have excellent heat resistance, they tend to harden when exposed to high temperatures. Therefore, when the fuel cell stack is repeatedly started and stopped, causing temperature changes, the sealing material made of vermiculite hardens at high temperatures, reducing its elasticity and surface pressure. As a result, the sealing performance of the sealing material deteriorates, making it more susceptible to reactant gas leakage.

[0007] An object of the present invention is to provide an annular packing material that maintains high sealing and insulating properties even when exposed to temperature changes including high-temperature environments, an electrochemical module including this annular packing material, an electrochemical device including this electrochemical module, an energy system including this electrochemical device, a solid oxide fuel cell including the electrochemical module, and a solid oxide electrolysis cell including the electrochemical module. [Means for solving the problem]

[0008] The annular packing material according to the present invention for achieving the above object has the following characteristic configuration: An annular packing material that electrically insulates adjacent members, a metal material made of a thermal expansion member that expands due to heat; At least one side of the metal material in the thickness direction an insulating metal oxide layer, and a through hole is formed inside the annularly formed metal material and the metal oxide layer; The cross-sectional shape of the metal material is a triangular shape, a sawtooth shape, a wave shape, a circular shape, an elliptical shape, O-shape Shape and and D The point is that it has one or more of the following character shapes.

[0009] According to the above characteristic configuration, when exposed to a high-temperature environment, the expansion tension of the metal material increases the surface pressure, thereby providing high sealing performance between the inside and outside of the metal material and the metal oxide layer (between the inside and outside of the ring). Furthermore, since the metal material is difficult to harden even when exposed to high temperatures, it can withstand long-term use accompanied by temperature changes, including high-temperature environments. An insulating material provided on at least one side of the metal material in the thickness direction The metal oxide layer also maintains the insulating properties. Furthermore, according to the above-described characteristic configuration, the metal material can be formed in various shapes, which broadens the range of applications.

[0012] A further characteristic feature of the annular packing material according to the present invention is that the metal oxide layer contains one or more of alumina, silica, magnesium oxide, iron oxide, chromium oxide, and manganese oxide.

[0013] According to the above characteristic configuration, the metal oxide layer can be made from readily available materials.

[0014] A further characteristic feature of the annular packing material according to the present invention is that the metal material includes at least one of ferritic stainless steel, austenitic stainless steel, Inconel, copper, and Invar material.

[0015] According to the above characteristic configuration, the metal material can be made from readily available materials.

[0016] A further characteristic feature of the annular packing material according to the present invention is that the cross-sectional shape of the metal material is an annular shape having a closed space inside.

[0017] According to the above characteristic configuration, when exposed to a high-temperature environment, the thermal expansion of the gas or liquid sealed in the closed space (internal space) formed inside the ring shape further promotes the expansion of the metal material, thereby increasing the surface pressure, and as a result, even higher sealing performance is achieved.

[0018] A further characteristic feature of the annular packing material according to the present invention is that the metallic material is a bimetal.

[0019] According to the above characteristic configuration, the seal is configured to change into a specific shape in response to temperature changes, so that when exposed to a high-temperature environment, the change in shape increases the surface pressure, resulting in even higher sealing performance.

[0022] The electrochemical module according to the present invention, which is intended to achieve the above-mentioned object, has a characteristic configuration in that a plurality of electrochemical elements, each of which includes an electrolyte layer and a first electrode and a second electrode disposed on either side of the electrolyte layer, are stacked with metal substrates interposed between the electrochemical elements, and the annular packing material is disposed between adjacent metal substrates.

[0023] According to the above characteristic configuration, even if the electrochemical module is placed in an environment where temperatures change, including high temperatures, the metal material is resistant to hardening, so it can withstand long-term use. Furthermore, when exposed to a high-temperature environment, the expansion force of the metal material increases the surface pressure, providing high sealing performance, thereby ensuring sufficient sealing between adjacent metal substrates. Furthermore, the formation of a metal oxide layer also maintains insulation between adjacent metal substrates.

[0024] A further characteristic feature of the electrochemical module according to the present invention is that the thermal expansion coefficient of the metal material is different from the thermal expansion coefficient of the metal substrate.

[0025] According to the above characteristic configuration, when exposed to a high-temperature environment, the surface pressure can be increased by utilizing the thermal expansion force generated by the difference in thermal expansion between the metal substrate and the metal material, resulting in even higher sealing performance.

[0026] A further characteristic feature of the electrochemical module according to the present invention is that the annular packing material is arranged between the metal substrate and the annular packing material with ceramic paste applied to at least a portion of its surface.

[0027] According to the above-mentioned characteristic configuration, the minute gap between the annular packing material and the metal substrate is filled with the ceramic paste, thereby achieving even higher sealing performance.

[0028] A further characteristic feature of the electrochemical module according to the present invention is that the ceramic paste contains mica.

[0029] According to the above-mentioned characteristic configuration, the ceramic paste contains mica, which has been experimentally confirmed to provide high sealing properties.

[0030] The electrochemical device according to the present invention, which is intended to achieve the above object, is characterized by having at least the above electrochemical module and a fuel converter which generates a reducing component to be supplied to the electrochemical module or converts a gas containing the reducing component generated in the electrochemical module.

[0031] According to the above-mentioned characteristic configuration, when the electrochemical module is operated as a fuel cell, it can be configured to generate hydrogen using a fuel converter such as a reformer from natural gas or the like supplied using existing raw fuel supply infrastructure such as city gas, thereby realizing an electrochemical device equipped with an electrochemical module that is excellent in durability, reliability, and performance.In addition, it becomes easy to build a system for recycling unused fuel gas circulated from the electrochemical module, thereby realizing a highly efficient electrochemical device. On the other hand, when the electrochemical module is operated as an electrolysis cell, gas containing water vapor and carbon dioxide is passed through the electrode layer, and a voltage is applied between the electrode layer and the counter electrode layer. Then, electrons e - reacts with water molecules H2O and carbon dioxide molecules CO2 to produce hydrogen molecules H2, carbon monoxide CO and oxygen ions O 2- The generated oxygen ions O 2- moves through the electrolyte layer to the counter electrode layer, where oxygen ions O 2- releases electrons and becomes oxygen molecules O2. Through the above reaction, when gas containing water vapor is passed through, water molecules H2O are decomposed into hydrogen H2 and oxygen O2, and when gas containing carbon dioxide molecules CO2 is passed through, it is electrolyzed into carbon monoxide CO and oxygen O2. Therefore, when gas containing water vapor and carbon dioxide molecules (CO2) is circulated, a fuel converter can be provided that synthesizes various compounds such as hydrocarbons from the hydrogen and carbon monoxide produced in the electrochemical module by the electrolysis described above. This allows the hydrocarbons produced by the fuel converter to be circulated to the electrochemical module or extracted outside the system / device and used separately as fuel or chemical raw materials.

[0032] Another electrochemical device according to the present invention for achieving the above object is characterized by having the above electrochemical module and a power converter that extracts power from the electrochemical module or passes power to the electrochemical module.

[0033] According to the above characteristic configuration, the power converter extracts power generated by the electrochemical module or distributes power to the electrochemical module. As a result, the electrochemical module functions as a fuel cell or an electrolysis cell. Therefore, according to the above configuration, it is possible to provide an electrochemical device that can improve the efficiency of converting chemical energy such as fuel into electrical energy or converting electrical energy into chemical energy such as fuel. For example, using an inverter as a power converter is preferable because it can boost the electrical output obtained from an electrochemical module, which has excellent durability, reliability, and performance, or convert DC to AC, making it easier to utilize the electrical output obtained from the electrochemical module. Furthermore, when used for electrolysis, it is preferable because it can obtain DC from an AC power source and construct an electrochemical device that can supply DC power to an electrochemical element or electrochemical module.

[0034] To achieve the above object, the energy system according to the present invention is characterized by having the electrochemical device and a waste heat utilization section that reuses heat discharged from the electrochemical device.

[0035] According to the above characteristic configuration, since the electrochemical device and the waste heat utilization unit that reuses the heat discharged from the electrochemical device are included, it is possible to realize an energy system that is excellent in durability, reliability, performance, and energy efficiency. Furthermore, it is also possible to realize a hybrid system with excellent energy efficiency by combining it with a power generation system that generates electricity by utilizing the combustion heat of unused fuel gas discharged from the electrochemical device.

[0036] In order to achieve the above object, a solid oxide fuel cell according to the present invention has a characteristic configuration in that it includes the above electrochemical module, and a power generation reaction occurs in the electrochemical module.

[0037] According to the above-described characteristic configuration, a power generation reaction can be performed in a solid oxide fuel cell equipped with an electrochemical module that is durable, reliable, and highly functional, thereby achieving a highly durable and high-performance solid oxide fuel cell. A solid oxide fuel cell that can operate at a temperature range of 650°C or higher during rated operation is preferable because it can be used in fuel cell systems that use hydrocarbon gases, such as city gas, as raw fuel, to generate the heat required for converting the raw fuel into hydrogen using the fuel cell's exhaust heat, thereby improving the power generation efficiency of the fuel cell system. A solid oxide fuel cell that operates at a temperature range of 900°C or lower during rated operation is more preferable because it can effectively suppress Cr volatilization from metal-supported electrochemical elements. A solid oxide fuel cell that operates at a temperature range of 850°C or lower during rated operation is even more preferable because it can further enhance the suppression of Cr volatilization.

[0038] To achieve the above object, a solid oxide electrolysis cell according to the present invention is characterized by including the above electrochemical module, and causing an electrolytic reaction in the electrochemical module.

[0039] According to the above characteristic configuration, a gas can be generated by an electrolytic reaction as a solid oxide electrolysis cell provided with an electrochemical element that is excellent in durability, reliability, and performance, and therefore a highly durable and high-performance solid oxide electrolysis cell can be obtained. [Brief explanation of the drawings]

[0040] [Figure 1] FIG. 1 is a cross-sectional view of an electrochemical module. [Figure 2] FIG. 2 is a top view of an electrochemical module. [Figure 3] FIG. 2 is a side view of an electrochemical module. [Figure 4] FIG. 1 is a schematic diagram of an electrochemical module. [Figure 5] FIG. 1 is a cross-sectional view of an electrochemical module according to Alternative Embodiment 1. [Figure 6] FIG. 10 is a cross-sectional view of an electrochemical module according to another embodiment 2. [Figure 7] FIG. 7 is a top view of the electrochemical module of FIG. 6. [Figure 8] FIG. 7 is a side view of the electrochemical module of FIG. 6. [Figure 9] FIG. 1 is a schematic diagram of an electrochemical device. [Figure 10] 10 is a cross-sectional view taken along the line XX in FIG. 9. [Figure 11] 10 is a cross-sectional view taken along the line XI-XI in FIG. 9. [Figure 12] 10 is a cross-sectional view taken along the line XII-XII in FIG. 9. [Figure 13] 10 is a cross-sectional view taken along the line XIII-XIII in FIG. 9. [Figure 14] 10 is a cross-sectional view taken along the line XIV-XIV in FIG. 9. [Figure 15] 10 is a cross-sectional view taken along the line XV-XV in FIG. 9. [Figure 16] 10 is a cross-sectional view taken along the line XVI-XVI in FIG. 9. [Figure 17] 10 is a cross-sectional view taken along the line XVII-XVII in FIG. 9. [Figure 18] FIG. 2 is an enlarged view of a main part of an electrochemical reaction section. [Figure 19] FIG. [Figure 20] FIG. 2 is a longitudinal cross-sectional view of an annular packing material. [Figure 21] FIG. 10 is a longitudinal sectional view of another type of annular packing material. [Figure 22] FIG. 10 is a longitudinal cross-sectional view of another type of annular packing material after heating. [Figure 23] FIG. 10 is a longitudinal sectional view of another type of annular packing material. [Figure 24] FIG. 10 is a longitudinal sectional view of another type of annular packing material. [Figure 25] FIG. 10 is a longitudinal sectional view of another type of annular packing material. [Figure 26]FIG. 10 is a longitudinal sectional view of another type of annular packing material. [Figure 27] FIG. 10 is a longitudinal sectional view of another type of annular packing material. [Figure 28] FIG. 10 is a longitudinal sectional view of another type of annular packing material. [Figure 29] FIG. 1 is a schematic diagram of an energy system. [Figure 30] FIG. 10 is an explanatory diagram of an electrochemical module according to another embodiment. [Figure 31] FIG. 1 is a schematic diagram of another energy system. [Figure 32] FIG. 10 is a longitudinal cross-sectional view of a modified annular packing material. [Figure 33] 10 is a table showing measurement results of gas leakage amounts. DETAILED DESCRIPTION OF THE INVENTION

[0041] [Embodiment] The following describes an electrochemical module M, an electrochemical device, and an energy system according to an embodiment of the present invention. When describing the positional relationship of layers, for example, the electrolyte layer side as viewed from the electrode layer is referred to as "top" or "upper side," and the first plate-like body side is referred to as "bottom" or "lower side." Furthermore, since the same effect can be obtained whether the electrochemical module M is installed vertically or horizontally in the present invention, "top" and "bottom" can also be read as "left" and "right," respectively.

[0042] (1) Overall configuration of electrochemical module M The overall configuration of the electrochemical module M will be described below. As shown in Fig. 1, the electrochemical module M includes an electrochemical element stack (stack) S and a roughly rectangular parallelepiped container (housing, first sandwiching body, second sandwiching body) 200 that houses the electrochemical element stack S. The electrochemical element A (Fig. 4) is an element that generates electricity using a power generation reaction, and is formed in a plate shape extending from the front to the back of the paper in the cross-sectional view of Fig. 1. The electrochemical element stack S is configured by stacking a plurality of flat plate-shaped electrochemical elements A in the vertical stacking direction in the cross-sectional view of Fig. 1. In this embodiment, an SOFC (Solid Oxide Fuel Cell) will be described as an example of the electrochemical element A.

[0043] The electrochemical module M also includes a first gas supply section 61 that supplies a first gas to the electrochemical element stack S from the outside of the container 200, and a first gas discharge section 62 that discharges the first gas after reaction in the electrochemical element stack S.

[0044] As shown in FIGS. 1 to 3, the container 200 is provided with a second gas supply unit 71, which supplies a second gas from outside the container 200 to the electrochemical element stack S. The second gas after the reaction in the electrochemical element stack S is discharged to the outside from a second gas discharge unit 72 provided in the container 200. Here, the first gas is a reducing gas such as a fuel gas, and the second gas is an oxidizing gas such as air.

[0045] 1, the electrochemical module M is provided with opening-equipped plate members (non-hard members) 240 on both side surfaces of the electrochemical element stack S. The opening-equipped plate members 240 are plate-shaped members that correspond to both side surfaces of the electrochemical element stack S and extend in the stacking direction of the electrochemical elements A, and are preferably made of an insulating material such as mica to prevent electrical short circuits in the electrochemical module M. The opening-equipped plate members 240 are formed with a plurality of openings 240a that penetrate along the planar direction of the electrochemical element stack S.

[0046] Thus, the electrochemical element laminate S receives a supply of fuel gas from the first gas supply unit 61 and a supply of air from the second gas supply unit 71 through the openings 240a of the opening-equipped plate member 240, and generates electricity by causing an electrochemical reaction between the fuel gas and oxygen in the air. The fuel gas after the electrochemical reaction is discharged to the outside from the first gas discharge unit 62. The air after the electrochemical reaction is led to the second gas discharge unit 72 through the openings 240a of the opening-equipped plate member 240 and discharged from the second gas discharge unit 72 to the outside.

[0047] Here, although aperture plate members 240 are provided adjacent to both side surfaces of the electrochemical element stack S, this is not essential, and either one may be provided, or both may be omitted.

[0048] The electrochemical module M also includes, at the top of the electrochemical element stack S, an upper insulator 210T, an upper flat plate member 220T, and an upper plate (first holding body) 230T, in that order from the electrochemical element stack S side to the outside. Similarly, the electrochemical module M also includes, at the bottom of the electrochemical element stack S, a lower insulator 210B, a lower flat plate member 220B, and a lower plate (second holding body) 230B, in that order from the electrochemical element stack S side to the outside. The electrochemical element laminate S will be described in detail later.

[0049] (2) Insulators, flat members, plates and containers The insulators (upper and lower insulators 210T and 210B) 210, the flat members (upper and lower flat members 220T and 220B) 220, the plates (upper and lower plates 230T and 230B) 230, and the container 200 will be further described below.

[0050] The upper insulator 210T is a plate-shaped member and is arranged so as to cover the upper flat surface (first flat surface) of the electrochemical element stack S. The upper insulator 210T is made of, for example, ceramics or hard mica, and electrically insulates the electrochemical element stack S from the outside.

[0051] The upper flat plate member 220T is disposed on top of the upper insulator 210T. The upper flat plate member 220T is an elastic member, and in this embodiment, is formed in a wave shape, for example, in the cross-sectional view of FIG. 1. The wave shape extends along the plane of the electrochemical element stack S. Therefore, the upper flat plate member 220T is disposed so that the top of the wave shape comes into contact with the upper insulator 210T. The thickness of the corrugated upper flat plate member 220T is, but is not limited to, about 0.1 mm to 1 mm, for example, and the amplitude (height) of the corrugation is, but is not limited to, about 1 mm to 10 mm, for example. The role of the upper flat plate member 220T will be described later.

[0052] The upper plate 230T is a plate-like member disposed on top of the upper flat plate-like member 220T and is made of a ceramic material with high bending strength at high temperatures, such as 99 alumina. The upper plate 230T contacts at least a portion of the upper flat plate-like member 220T. In this embodiment, the crests of the corrugations of the upper flat plate-like member 220T contact the upper plate 230T.

[0053] The upper plate 230T, together with the lower plate 230B, receives a predetermined clamping pressure from the container 200, and sandwiches the electrochemical element stack S, the pair of upper and lower insulators 210T and 210B, and the upper and lower flat plate members 220T and 220B. Here, the clamping pressure is, for example, 1 mm 2 The pressure per unit area is the pressure per square meter.

[0054] The lower insulator 210B is disposed so as to cover the lower flat surface (second flat surface) of the electrochemical element stack S. The lower flat plate-shaped member 220B is disposed below the lower insulator 210B, and the lower plate 230B is disposed below the lower flat plate-shaped member 220B. The lower insulator 210B, lower flat plate-shaped member 220B, and lower plate 230B are similar to the upper insulator 210T, upper flat plate-shaped member 220T, and upper plate 230T, respectively. Note that the crests of the corrugations of the lower flat plate-shaped member 220B contact the lower plate 230B, and the crests 220Bb contact the lower insulator 210B.

[0055] 1 to 3, the container 200 that houses the electrochemical element laminate S is a roughly rectangular parallelepiped container. The container 200 includes a box-shaped upper lid (first holding body) 201 that is open at the bottom, and a lower lid (second holding body) 203 that is open at the top. A connecting portion 202 is provided on the end face of the upper lid 201 that faces the lower lid 203, and a connecting portion 205 is provided on the end face of the lower lid 203 that faces the upper lid 201. The upper lid 201 and the lower lid 203 are connected by, for example, welding the connecting portion 202 and the connecting portion 205, thereby forming a rectangular parallelepiped space inside.

[0056] 1, the depth of the lower lid 203 in the vertical direction (the stacking direction of the electrochemical element A) is deeper than the depth of the upper lid 201. However, the relationship between the depths is not limited to this as long as the upper lid 201 and the lower lid 203 can integrally form a space therein. For example, the depth of the upper lid 201 may be deeper than the depth of the lower lid 203.

[0057] As shown in FIGS. 1 to 3, a second gas supply part 71 and a second gas discharge part 72 are formed on a pair of opposing side walls of the lower lid 203 at the center of the container 200 in the vertical direction.

[0058] Here, the second gas supply unit 71 and the second gas exhaust unit 72 are formed in the lower lid 203. However, the positions at which the second gas supply unit 71 and the second gas exhaust unit 72 are formed are not limited thereto, and they may be formed in any position in the container 200. The second gas supply unit 71 and the second gas exhaust unit 72 may be formed in the upper lid 201, for example.

[0059] As shown in FIGS. 1 and 2, the top lid 201 has an opening 201c that is slightly smaller than the outer edge of the top lid 201. In the cross-sectional view of FIG. 1, adjacent to the opening 201c, the inner end facing the electrochemical element laminate S branches into a first end 201a and a second end 201b. The first end 201a extends a predetermined length in a planar direction toward the inside of the container 200, and the second end 201b branches from the first end 201a and extends a predetermined length downward of the container 200. The first end 201a and the second end 201b form an angle of approximately 90° in the cross-sectional view, forming an L-shaped corner. This L-shaped corner is formed along the outer edge of the top lid 201 shown in FIG. 2, on the inner side of the outer edge. As a result, an opening 201c that is slightly smaller than the outer edge of the top cover 201 is formed in the top surface of the top cover 201 at the end of the first end 201a, as shown in FIGS.

[0060] Similar to the upper cover 201, the lower cover 203 has a first end 203a and a second end 203b that form L-shaped corners at an angle of approximately 90° in the cross-sectional view shown in Fig. 1. The end of the first end 203a forms an opening 203c that is slightly smaller than the outer edge of the lower cover 203, as shown in Fig. 1.

[0061] As shown in FIG. 1 , the upper ends of a pair of opening-equipped plate members 240, an upper insulator 210T, an upper flat plate member 220T, and an upper plate 230T are fitted into the L-shaped corner formed by the first end 201a and the second end 201b of the upper lid 201. Specifically, the upper plate 230T, which is aligned along the planar direction of the electrochemical element stack S, is supported with the upper surface of its outer circumferential edge in contact with the lower surface of the first end 201a (part of the inner surface of the L-shaped corner). The opening-equipped plate member 240, which is aligned along the side surface of the electrochemical element stack S, is supported with the outer surface of its upper end in contact with the inner side surface of the second end 201b (part of the inner surface of the L-shaped corner). The upper flat plate member 220T and the upper insulator 210T are supported by the L-shaped corner formed by the first end 201a and the second end 201b via the upper plate 230T and the opening-equipped plate member 240.

[0062] Similarly, the lower ends of a pair of opening plate members 240, a lower insulator 210B, a lower flat plate member 220B, and a lower plate 230B are fitted into a pair of L-shaped corners facing each other in the planar direction of the lower cover 203. The upper surface of the electrochemical element stack S is supported by the upper lid 201 via an upper plate 230T, an upper flat plate member 220T, and an upper insulator 210T. The lower surface of the electrochemical element stack S is supported by the lower lid 203 via a lower plate 230B, a lower flat plate member 220B, and a lower insulator 210B.

[0063] With this configuration, the upper lid 201 and the lower lid 203 sandwich the electrochemical element stack S, the upper and lower insulators 210T and 210B, the upper and lower flat plate-like members 220T and 220B, the upper and lower plates 230T and 230B, etc., from above and below, and are connected to each other by, for example, welding between the connecting portion 202 and the connecting portion 205. During this connection, the upper lid 201 and the lower lid 203 are connected by applying a predetermined load to the electrochemical element stack S, etc. In other words, with the upper lid 201 and the lower lid 203 connected, a predetermined load is applied to the electrochemical element stack S, the upper and lower insulators 210T and 210B, the upper and lower flat plate-like members 220T and 220B, and the upper and lower plates 230T and 230B, and they are tightened.

[0064] 3, an opening 203e is formed in the side surface of the lower lid 203. Therefore, a part of the side surface of the electrochemical element laminate S is exposed through the opening 203e. By forming the openings 201c, 203c, and opening 203e in the container 200, the weight of the container 200 can be reduced, and the amount of material required for the container 200 can be reduced. If there is a possibility of an electrical short circuit due to contact between the side surface of the electrochemical element laminate S and the upper lid 201 or the lower lid 203, or both, a side surface insulator (not shown) made of a material such as mica is placed between the electrochemical element laminate S and the side surface of the upper lid 201 or the lower lid 203.

[0065] (3) Structure and function of flat plate-shaped members and related members Next, the configuration and operation of the flat plate-like members (upper and lower flat plate-like members 220T and 220B) 220 and related members will be further described.

[0066] As described above, when the upper lid 201 and the lower lid 203 are connected, the electrochemical element stack S and the upper and lower insulators 210T and 210B are clamped between the upper and lower plates 230T and 230B via the upper and lower flat members 220T and 220B with a predetermined clamping pressure applied.

[0067] (3-1) Structure of flat plate-shaped members and related members In this embodiment, the flat plate member 220 is made of a thermal expansion member that expands due to heat. The thermal expansion coefficient (hereinafter the same) of the flat plate member 220 is preferably greater than the thermal expansion coefficient of the members that make up the electrochemical element stack S, the container 200, etc. Examples of materials for such flat plate member 220 include austenitic stainless steel.

[0068] The thermal expansion coefficient of austenitic stainless steel is relatively large. For example, the thermal expansion coefficient of aluminum is approximately 23.8 x 10 -6 / °C, whereas the thermal expansion coefficient of austenitic stainless steel is as large as that of aluminum. The thermal expansion coefficient of austenitic stainless steel is approximately 17.3 x 10 for SUS303 and SUS304. -6 / ℃, and SUS316 is approximately 16×10 -6 / ° C. However, the material of the flat plate member 220 is not limited to this, and it is preferable to select a material that has a thermal expansion coefficient greater than that of the container 200 and the like and that has excellent corrosion resistance.

[0069] Furthermore, it is preferable that the thermal expansion coefficient of the container 200 is smaller than that of the flat plate-like member 220. The container 200 is disposed adjacent to the flat plate-like member 220 with the plate 230 interposed therebetween. When the lower lid 203 and the upper lid 201 of the container 200 are joined together, a clamping pressure is applied to the electrochemical element stack S via the flat plate-like member 220. Examples of materials for such a container 200 include ferritic stainless steel, martensitic stainless steel, and composites of these with ceramics. These materials have a smaller thermal expansion coefficient than austenitic stainless steel, and the thermal expansion coefficient of ferritic stainless steel is about 11×10 for SUS430. -6 / ℃. The thermal expansion coefficient of martensitic stainless steel is approximately 10.4 × 10 for SUS403 and SUS420J1. -6 / ℃, and SUS410 and SUS440C are approximately 10.1 × 10 -6 / ° C. However, the container 200 is not limited to this, and it is preferable to select a material that has a thermal expansion coefficient smaller than that of the flat plate-shaped member 220 and has excellent corrosion resistance.

[0070] The material of the electrochemical element laminate S is preferably the same as that of the container 200. In other words, the materials of the electrochemical element laminate S and the container 200 preferably have the same thermal expansion coefficient as that of the container 200. In this case, the substrate of the electrochemical element laminate S and the container 200 thermally expand to the same extent, for example, during power generation when the electrochemical element A reaches a high temperature. Therefore, for example, the difference in thermal expansion between the substrate of the electrochemical element A and the container 200 can be kept small, and damage to the substrate can be prevented.

[0071] (3-2) Assembly method of electrochemical module M and compression displacement of flat plate members during assembly (a) Assembly method of electrochemical module M Next, a method for assembling the electrochemical module M will be described. A plurality of electrochemical elements A are stacked to prepare an electrochemical element stack S. The configuration and manufacturing method of the electrochemical element stack S will be described later.

[0072] A container 200 for containing the electrochemical element laminate S is also prepared. The container 200 can be manufactured using, but is not limited to, a lost-wax casting method. When using the lost-wax casting method, a hollow model corresponding to the outer shape of the container 200 is manufactured using a thermoplastic material such as beeswax or rosin. This model is then covered with a refractory material such as silica sand or lime powder. The model covered with the refractory material is then heated to dissolve the thermoplastic model. This forms a cavity within the refractory material that corresponds to the model's shape, imitating the shape of the container 200. The material for the container 200 is poured into this cavity and solidified, and the refractory material is then removed. This results in the container 200 having an upper lid 201 and a lower lid 203 manufactured using the lost-wax casting method. Note that the upper lid 201 and the lower lid 203 may be manufactured separately.

[0073] Next, for example, a pair of opening-equipped plate members 240 are placed on both side surfaces of the electrochemical element stack S, and the insulator 210, flat plate-like member 220, and plate 230 are placed in this order on the upper and lower flat surfaces of the electrochemical element stack S, and the electrochemical element stack S is housed in the lower lid 203. The lower lid 203 is covered with the upper lid 201, and the position is adjusted so that a predetermined clamping pressure is applied to the electrochemical element stack S, and the lower lid 203 and the upper lid 201 are joined by welding or the like. In this way, the electrochemical module M is assembled.

[0074] As described above, when the container 200 is manufactured using the lost wax casting method, it is possible to achieve cost reduction through thinning, precision, and mass production. Furthermore, by forming the box-shaped container 200, in this embodiment, a space for a manifold for supplying air from the second gas supply unit 71 to the electrochemical element stack S can be provided.

[0075] (b) Compression displacement of flat plate members during assembly When assembling the electrochemical module M, a predetermined clamping pressure is applied to the electrochemical element stack S when joining the lower lid 203 and the upper lid 201. This clamping pressure is applied by giving a predetermined compressive displacement L to the flat plate-like member 220.

[0076] This compression displacement L will be explained below. In the following description, it is assumed that the container 200 is made of a predetermined material Y1, the main parts of the electrochemical element stack S, such as the substrate, are made of a predetermined material Y2, and the flat plate-like member 220 is made of a predetermined material Y3. The thermal expansion coefficient of material Y3 is greater than the thermal expansion coefficients of materials Y1 and Y2.

[0077] Here, the flat plate member 220 has a spring constant of K20 at room temperature (20° C.) The spring constant K20 is calculated using, for example, the plate thickness of the flat plate member 220, the amplitude (height) of the waveform shape, and the wave pitch. The spring constant is K700 at the temperature (for example, 700° C.) during power generation by the electrochemical device A. K700 is, for example, approximately 75% of K20.

[0078] Here, the clamping pressure per unit area required by the electrochemical element laminate S during power generation (for example, at 700°C) is defined as P. Here, P is not limited to this value, but may be, for example, about 1 to 3 kgf / cm. 2 If the area of ​​the electrochemical element stack S is SB, the applied force F is given by F=P×SB.

[0079] Furthermore, when the temperature rises from room temperature (20°C) to a high temperature during power generation (e.g., 700°C), in the load direction (here, the stacking direction of the electrochemical element A), the thermal expansion length of the container 200 is defined as LA, the thermal expansion length of the electrochemical element stack S is defined as LB, and the thermal expansion length of the flat plate-shaped member 220 is defined as LC.

[0080] The difference ΔG in thermal expansion length between the container 200 and the electrochemical element stack S is ΔG=LA-LB. Here, the difference in thermal expansion length ΔG may be calculated as the difference in thermal expansion length between the container 200, the electrochemical element stack S, and the flat plate-like member 220. In this case, ΔG=LA-(LB+LC). In the following, by assuming that the flat plate-like member 220 does not thermally expand, ΔG=LA-LB is used so that an appropriate clamping pressure can be more reliably applied by the compressive displacement L of the flat plate-like member 220 during assembly even after the container 200 etc. have thermally expanded.

[0081] Here, in order to maintain the clamping pressure P per unit area at high temperatures (for example, 700° C.) during power generation, the compression displacement L of the flat plate member 220 at room temperature (20) is calculated using the following formula. L=P×SB / (K700)+ΔG

[0082] As described above, after the electrochemical element stack S, the flat plate-like member 220, etc. are housed in the container 200, the lower lid 203 and the upper lid 201 are sealed by welding or the like, with the bond distance or the like adjusted so as to impart the above-calculated compressive displacement L to the flat plate-like member 220. This allows a predetermined clamping pressure to be applied to the electrochemical element stack S.

[0083] (3-3) Function of flat plate members As described above, the flat plate-like member 220 made of a thermal expansion member is placed on the upper and lower planes of the electrochemical element stack S, and is subjected to a predetermined clamping pressure from the upper and lower plates 230, thereby elastically supporting the electrochemical element stack S.

[0084] Here, for example, at least one of the electrochemical element laminate S and the container 200 expands when the electrochemical element A changes from a low temperature (for example, room temperature, about 20°C) when the electrochemical element A is not generating electricity to a high temperature (for example, about 650°C to about 950°C) when the electrochemical element A is generating electricity. If a difference in thermal expansion occurs between the electrochemical element laminate S and the container 200 at this time, the distance between the electrochemical element laminate S and the container 200 will be different when power is being generated (high temperature) and when power is not being generated (low temperature).

[0085] According to the above configuration, since the flat plate-shaped member 220 is a thermally expandable member, the flat plate-shaped member 220 also thermally expands when the electrochemical elements A reach a high temperature during power generation. Therefore, even if the distance between the electrochemical element stack S and the container 200 fluctuates due to thermal expansion, the flat plate-shaped member 220 applies an appropriate clamping pressure to the electrochemical element stack S, using the plate 230 as a pressing surface, by utilizing the elastic force generated by the thermal expansion of the flat plate-shaped member 220 itself and the elastic force due to the pre-given compression displacement L.

[0086] That is, the variation in the gap between the electrochemical element stack S and the container 200 due to thermal expansion can be compensated for by the variation due to thermal expansion of the flat plate-shaped member 220. Therefore, even after the aforementioned gap has varied, an appropriate clamping pressure is applied to the electrochemical element stack S. For example, the gap between the electrochemical element stack S and the container 200 that has increased due to thermal expansion is compensated for by the thermal expansion of the flat plate-shaped member 220, and an appropriate clamping pressure is applied to the electrochemical element stack S.

[0087] Furthermore, since the flat plate-like member 220 is arranged along the plane of the electrochemical element stack S and the plane of the plate 230, an appropriate clamping pressure is applied generally uniformly along the plane of the electrochemical element stack S even after the aforementioned gap has changed. This makes it possible to prevent a decrease in the contact area between the electrochemical elements A in the electrochemical module M, thereby reducing internal resistance. Furthermore, since the electrochemical elements A can be kept in appropriate contact with each other to maintain airtightness, it is possible to prevent fuel gas and the like from leaking outside the electrochemical elements A, and to prevent a decrease in the sealing performance for the reactant gas.

[0088] In this way, a small, lightweight, and low-cost electrochemical module can be achieved that can adequately fasten the electrochemical element stack S, etc., even when the electrochemical element stack S, etc., expands.

[0089] In particular, in the above embodiment, the thermal expansion coefficient of the flat plate-shaped member 220 is greater than the thermal expansion coefficient of the members constituting the container 200. To achieve this relationship, for example, austenitic stainless steel is used as the material for the flat plate-shaped member 220, and ferritic stainless steel, martensitic stainless steel, or a composite of these with ceramics is used as the material for the container 200. Furthermore, the same material as that of the container 200 is used as the material for the electrochemical element laminate S.

[0090] As described above, when the electrochemical element laminate S changes from a low-temperature state where no power is generated to a high-temperature state where power is generated, at least one of the electrochemical element laminate S and the container 200 thermally expands, resulting in a difference between the amount of thermal expansion of the electrochemical element laminate S and the amount of thermal expansion of the container 200. As a result, the gap between the electrochemical element laminate S and the container 200 at high temperatures becomes larger than at low temperatures. For example, if the amount of thermal expansion of the container 200 is relatively large, the gap between the electrochemical element laminate S and the container 200 becomes larger.

[0091] In this embodiment, as described above, the thermal expansion coefficient of the flat plate-shaped member 220 is greater than the thermal expansion coefficient of the members constituting the container 200. Therefore, the thermal expansion of the flat plate-shaped member 220 can compensate for the gap between the electrochemical element stack S and the container 200, which has increased due to the expansion of the container 200 in particular. In other words, even if the gap between the electrochemical element stack S and the container 200 changes significantly due to thermal expansion, the flat plate-shaped member 220, which thermally expands even more, can compensate for the gap. Therefore, even after this gap has changed, an appropriate clamping pressure can be applied approximately uniformly along the plane of the electrochemical element stack S due to the elastic force caused by the compressive displacement previously applied to the flat plate-shaped member 220 and the elastic force generated by the thermal expansion of the flat plate-shaped member 220 itself.

[0092] If the thermal expansion coefficient of the container 200 is relatively small, the amount of thermal expansion of the container 200 can be kept small, for example, when the container 200 becomes hot during power generation. This makes it possible to keep the increase in the gap between the electrochemical element stack S and the container 200 due to thermal expansion small. Therefore, even if the thermal expansion coefficient of the flat plate-shaped member 220 is relatively small, an appropriate clamping pressure can be applied generally uniformly along the plane of the electrochemical element stack S after the gap changes. Furthermore, if the amount of thermal expansion of the container 200 is small, displacement and damage to the substrates of the electrochemical device A due to the expansion of the container 200 can be suppressed.

[0093] In the above embodiment, the flat plate member 220 is formed in a corrugated shape, and therefore, the peaks of the corrugations of the flat plate member 220 are alternately in contact with the flat surface of the plate 230 and the flat surface of the electrochemical element stack S via the insulator 210 at multiple dispersed locations.

[0094] Here, when the gap between the electrochemical element stack S and the container 200 fluctuates due to expansion of at least one of the electrochemical element stack S and the container 200, the pressing force applied to the flat plate-like member 220 also fluctuates due to this gap fluctuation. This fluctuating pressing force is elastically absorbed by the flat plate-like member 220 in a state in which it is distributed substantially uniformly along substantially the entire plane of the electrochemical element stack S and the plane of the plate 230. This is because, as described above, the flat plate-like member 220 is in contact with the plane of the electrochemical element stack S and the plane of the plate 230 at multiple dispersed points. Furthermore, when the flat plate-like member 220 undergoes thermal fluctuation, the fluctuation in the gap between the electrochemical element stack S and the container 200 is absorbed at the multiple points described above by the thermal expansion and elasticity of the flat plate-like member 220 itself.

[0095] Therefore, even if the gap between the electrochemical element stack S and the container 200 fluctuates due to expansion of the electrochemical element stack S, etc., the flat plate-like member 220 can apply an appropriate clamping pressure in the stacking direction substantially uniformly along the plane of the electrochemical element stack S. This makes it possible to suppress an increase in internal resistance and a decrease in the sealing performance for reaction gases in the electrochemical module M, while also achieving miniaturization and weight reduction.

[0096] In this embodiment, the electrochemical element stack S is composed of an SOFC, which is an electrochemical element. The temperature of an SOFC reaches high temperatures of approximately 650°C to approximately 950°C during power generation. Therefore, the expansion of the electrochemical element stack S and the container 200 increases as the temperature changes from a low temperature (e.g., room temperature of approximately 20°C) during non-power generation to a high temperature (e.g., approximately 650°C to approximately 950°C) during power generation. In this embodiment, the flat plate-like member 220 can apply an appropriate clamping pressure to the electrochemical element stack S by using the plate 230 as a pressing surface, utilizing the change in elastic force due to the thermal expansion of the flat plate-like member 220 itself. Therefore, even in an SOFC or the like that generates power in a high-temperature range, this embodiment can be applied to apply an appropriate clamping pressure to the electrochemical element stack S.

[0097] The miniaturization of the electrochemical module M will be further described. For example, in a configuration in which a clamping pressure is applied to the electrochemical element stack S by clamping the periphery of a pair of thick clamping plates, it is necessary to arrange large clamping bolts using springs on the outside of the electrochemical module M as clamping members. However, in the above embodiment, it is only necessary to arrange the flat plate-shaped member 220 inside the electrochemical module M, and the electrochemical module M can be made smaller.

[0098] Furthermore, if protrusions such as large tightening bolts are disposed on the outside of the electrochemical module M, heat is more likely to be dissipated during power generation by such protrusions on the electrochemical module M. Since the flat plate-shaped member 220 of this embodiment is disposed inside the electrochemical module M, the heat dissipation surface can be reduced, and the power generation efficiency of the electrochemical module M can be improved.

[0099] Furthermore, in this embodiment, the tightening pressure is adjusted by the flat plate-shaped member 220, which significantly reduces the effort required to adjust the tightening pressure compared to adjusting the tightening pressure of the electrochemical element stack S using multiple large tightening bolts or the like. For example, when multiple large tightening bolts are used to tighten the electrochemical element stack S, it is necessary to adjust the pressure while managing the torque of the multiple bolts. However, when the flat plate-shaped member 220 of this embodiment is used, the flat plate-shaped member 220 applies a generally uniform tightening pressure to the plane of the electrochemical element stack S, eliminating the need for the complex torque management described above.

[0100] (4) Specific configuration of electrochemical module M Next, a specific configuration of the electrochemical module M will be described with reference to Figures 1 and 4. The electrochemical element stack S of Figure 1 is shown in detail in Figure 1.

[0101] As shown in Figures 1 and 4, the electrochemical module M includes a container 200 (top lid 201 and bottom lid 203) that houses an electrochemical element stack S, a first gas supply unit 61 that supplies a first gas from the outside of the container 200 to the internal flow path A1 via a supply path 4, a first gas discharge unit 62 that discharges the first gas after the reaction, a second gas supply unit 71 that supplies a second gas from the outside of the container 200 to the flow section A2, a second gas discharge unit 72 that discharges the second gas after the reaction, and an output unit 8 that obtains an output associated with the electrochemical reaction in the electrochemical reaction section 3, and a distribution chamber 9 within the container 200 that distributes the second gas supplied from the second gas supply unit 71 to the flow section A2.

[0102] The distribution chamber 9 is a space located on the side of the electrochemical element stack S that supplies the second gas to the electrochemical element stack S, and the flow passage A2 is opened on the space side and communicates with the space.

[0103] The electrochemical element laminate S is housed within the container 200 in a state where it is sandwiched between a pair of current collectors 81, 82, and an output section 8 is extended from these current collectors 81, 82 and is connected freely to a power supply destination outside the container 200 so as to supply power, and at least one of the current collectors 81, 82 is electrically insulated from the container 200 and is contained in the container 200 so as to keep the first gas airtight.

[0104] As a result, the electrochemical module M is supplied with fuel gas from the first gas supply unit 61 and air from the second gas supply unit 71, so that fuel gas enters as shown by the dashed arrows in Figures 1 and 4 and air enters as shown by the solid arrows.

[0105] The fuel gas supplied from the first gas supply unit 61 is guided to the supply channel 4 through the first through-hole 41 of the uppermost electrochemical element A of the electrochemical element stack S, and flows through the supply channel 4 partitioned by a first annular packing material 42 (details of which will be described later) to the internal flow paths A1 of all the electrochemical elements A. In addition, the air supplied from the second gas supply unit 71 temporarily flows into the distribution chamber 9, and then flows through the flow passages A2 formed between the electrochemical elements A.

[0106] Incidentally, when the second plate-like body 2 (part of the plate-like support body 10 (an example of a metal substrate)) is used as a reference, an internal flow path A1 is formed between the first plate-like body 1 and the second plate-like body 2 at the portion where the corrugated second plate-like body 2 bulges out from the first plate-like body 1 (part of the plate-like support body 10 (an example of a metal substrate)), and the corrugated second plate-like body 2 comes into contact with the electrochemical reaction section 3 of the adjacent electrochemical element A, enabling electrical connection. Meanwhile, the portion where the corrugated second plate-like body 2 comes into contact with the first plate-like body 1 is electrically connected to the first plate-like body 1, and a flow section A2 is formed between the second plate-like body 2 and the electrochemical reaction section 3 of the adjacent electrochemical element A.

[0107] 18 shows, for convenience, an electrochemical element A showing a cross section including the internal flow path A1 and an electrochemical element A showing a cross section including the flow section A2, but the fuel gas supplied from the first gas supply section 61 reaches the distribution section A12 (see FIGS. 9, 12, and 15), spreads along the width direction of one end side through the distribution section A12, and reaches each sub-flow path A11 of the internal flow path A1 (see FIGS. 9, 11, and 15). In this case, the first gas can be distributed evenly from the distribution section A12 to the multiple sub-flow paths A11, and each electrochemical element can generate an equal electrochemical output.

[0108] As a result, the fuel gas that has entered the internal flow path A1 can enter the electrode layer (first electrode) 31 and the electrolyte layer 32 via the gas flow permitting portion 1A. The fuel gas further travels through the internal flow path A1 together with the fuel gas that has undergone the electrochemical reaction, passes through the confluence portion A13 and the second through portion 51, and proceeds to the discharge path 5 formed by the second annular packing material 52 (details of which will be described later), and is discharged to the outside of the container 200 from the first gas discharge portion 62 together with the fuel gas that has undergone the electrochemical reaction from the other electrochemical elements A.

[0109] On the other hand, the air supplied from the second gas supply unit 71 enters the flow section A2 via the distribution chamber 9, and can then enter the counter electrode layer (second electrode) 33 and the electrolyte layer 32. The air further travels through the flow section A2 along the electrochemical reaction unit 3 together with the air that has undergone the electrochemical reaction, and is discharged to the outside of the container 200 from the second gas discharge section 72.

[0110] The electricity generated in the electrochemical reaction section 3 in accordance with the flow of the fuel gas and air is connected in series between the current collectors 81, 82 due to contact between the electrochemical reaction section 3 of the adjacent electrochemical element A and the second plate-like body 2, and the combined output is taken out from the output section 8. The configuration of the electrochemical element stack S will be described in detail later.

[0111] (5) Modified examples of flat plate-shaped members (a) In the above, the flat plate member 220 is a thermal expansion member that expands due to heat. However, the flat plate member 220 is not limited to a thermal expansion member as long as it is a member that can apply a generally uniform clamping pressure to the plane of the electrochemical element stack S when the electrochemical element stack S and the container 200 expand and contract. For example, the flat plate member 220 may be a member that has a small coefficient of thermal expansion but a certain degree of elasticity.

[0112] The elastic flat plate members 220 are arranged along the upper and lower flat surfaces of the electrochemical element stack S. A predetermined clamping pressure is applied to the flat plate members 220 from the container 200 via the upper and lower plates 230, and the flat plate members 220 elastically support the electrochemical element stack S.

[0113] Here, when at least one of the electrochemical element stack S and the container 200 expands, the gap between the electrochemical element stack S and the container 200 may vary before and after the expansion of the electrochemical element stack S. Because the flat plate-like member 220 has elasticity, even if the gap between the electrochemical element stack S and the container 200 varies, the flat plate-like member 220 elastically sandwiches the electrochemical element stack S within the container 200 by using that elasticity. In other words, the flat plate-like member 220 receives a clamping pressure from the container 200 and elastically sandwiches the electrochemical element stack S between the pair of plates 230.

[0114] More specifically, when the gap between the electrochemical element stack S and the container 200 fluctuates due to expansion of at least one of the electrochemical element stack S and the container 200, the fluctuation in gap also fluctuates the pressing force applied to the flat plate-like member 220. This fluctuating pressing force is elastically received by the flat plate-like member 220 arranged along the plane of the electrochemical element stack S and the plane of the plate 230 in a state in which the pressing force is distributed substantially uniformly along substantially the entire plane of the electrochemical element stack S and the plane of the plate 230.

[0115] Therefore, even if the distance between the electrochemical element stack S and the container 200 changes due to expansion of the electrochemical element stack S, etc., the flat plate-shaped member 220 can apply an appropriate clamping pressure in the stacking direction approximately uniformly along the plane of the electrochemical element stack S. In this way, an electrochemical module M that takes into account the expansion of the electrochemical element stack S and the like can be constructed with a simple configuration in which a flat plate-like member 220 is placed between the plane of the electrochemical element stack S and the plane of the plate 230, along the plane of the electrochemical element stack S and the plate 230, and then stored in the container 200.

[0116] If the flat plate-like member 220 is a member with a small coefficient of thermal expansion, it is preferable to apply a larger clamping pressure when housing and assembling the flat plate-like member 220, electrochemical element stack S, etc. in the container 200 than when the flat plate-like member 220 is a member with a large coefficient of thermal expansion. In this case, a large repulsive force is generated in the flat plate-like member 220 during assembly due to the large clamping pressure. Therefore, even if the gap between the electrochemical element stack S and the container 200 widens due to expansion of the electrochemical element stack S, etc., and the clamping pressure becomes smaller to some extent, an appropriate clamping pressure can be applied to the electrochemical element stack S.

[0117] (b) In the above, upper and lower flat plate-shaped members 220T, 220B are provided, but it is also possible to provide only one of the flat plate-shaped members 220. However, when upper and lower flat plate-shaped members 220T, 220B are provided, clamping pressure can be applied to the electrochemical element stack S from above and below by the flat plate-shaped members 220, which is preferable because clamping pressure can be applied more uniformly to the plane of the electrochemical element stack S.

[0118] (c) In the above, the flat plate-like member 220 has a corrugated shape, but this is not limited thereto, and other configurations in which the flat plate-like member 220 comes into dispersed contact with the electrochemical element stack S and the plate 230, etc. at multiple locations may also be employed. For example, the flat plate-like member 220 may have a metal honeycomb shape.

[0119] The flat plate member 220 may also be in contact with only one of the flat surface of the electrochemical element stack S and the flat surface of the plate 230 at a plurality of dispersed locations. For example, the flat plate-like member 220 may be in contact with the plane of the electrochemical element stack S at multiple dispersed locations, and may be in surface contact with the plane of the plate 230. In this case, the flat plate-like member 220 receives the load force due to the expansion of the electrochemical element stack S and the like in a dispersed manner at the portions in contact with the electrochemical element stack S.

[0120] Furthermore, for example, the flat plate-like member 220 is in surface contact with the flat surface of the electrochemical element stack S, and may also be in contact at multiple points with the flat surface of the plate 230. In this case, the flat plate-like member 220 receives and distributes the load force due to the expansion of the electrochemical element stack S and the like at the portions in contact with the flat surface of the plate 230.

[0121] (d) In the above, the thermal expansion coefficient of the flat plate-shaped member 220 is greater than the thermal expansion coefficient of the members constituting the container 200. However, as long as the gap between the electrochemical element stack S and the container 200 caused by thermal expansion is compensated for by the expansion of the flat plate-shaped member 220, the relationship between the thermal expansion coefficients is not limited to this. For example, the thermal expansion coefficient of the flat plate-like member 220 may be approximately the same as or smaller than the thermal expansion coefficient of the member that constitutes the container 200 .

[0122] (e) In the above, the flat plate-shaped member 220 has been described as adjusting for variations in the gap between the electrochemical element stack S and the container 200 due to expansion. However, the flat plate-shaped member 220 can also be used to adjust for variations in the gap between the electrochemical element stack S and the container 200 due to contraction.

[0123] (f) In the above, the flat plate-like member 220 can absorb not only the temperature changes that accompany power generation, but also the expansion and contraction of the electrochemical element stack S and the container 200, etc., that occur due to, for example, vibrations applied to the electrochemical module M, external pressure, changes in humidity and outside temperature, etc.

[0124] (g) In the above, the electrochemical module M is provided with a functional layer such as an insulating insulator 210. The electrochemical module M may be provided with a separate functional layer in addition to or instead of the functional layer described above.

[0125] (h) In the above, the lower lid 203 and the upper lid 201 are joined by welding. However, the joining of the lower lid 203 and the upper lid 201 is not limited to welding, and they may be joined by, for example, bolts or the like.

[0126] (6) Specific Configuration of Electrochemical Element Laminate S Next, a specific configuration of the electrochemical element laminate S will be described. The electrochemical element laminate S is formed by laminating a plurality of electrochemical elements A. The electrochemical elements A will be described with reference to FIGS.

[0127] (electrochemical element) As shown in Figures 9 to 17, the electrochemical element A comprises a plate-like support 10 having an internal flow path A1 formed between the opposing surfaces of a conductive first plate-like body 1 and a conductive second plate-like body 2. The plate-like support 10 comprises, in at least a part of the first plate-like body 1 and the second plate-like body 2 constituting the plate-like support 10, a gas flow-permitting portion 1A that allows gas to pass between the internal flow path A1 on the inside of the plate-like support 10 and the outside, and an electrochemical reaction portion 3 that covers all or part of the gas flow-permitting portion 1A and has, in the stated order, a membrane-like electrode layer 31, a membrane-like electrolyte layer 32, and a membrane-like counter electrode layer 33 (see Figures 13 to 17). The plate-like support 10 also has a first through-portion 41 at one end forming a supply path 4 that supplies a first gas, which is one of a reducing component gas such as a fuel gas and an oxidizing component gas such as air, to the internal flow path A1 from the outside in the direction penetrating the surface, and a second through-portion 51 at the other end forming a discharge path 5 that discharges the first gas that has flowed through the internal flow path A1 outward in the direction penetrating the surface of the plate-like support (see Figures 9, 11, 16, and 17). It will be understood that the supply paths 4 and the discharge paths 5 are symmetrical and have similar structures.

[0128] (Plate-shaped support) The first plate-like body 1 supports the electrochemical reaction unit 3, which includes the electrode layer 31, the electrolyte layer 32, and the counter electrode layer 33, and serves to maintain the strength of the electrochemical device A. The material for the first plate-like body 1 is preferably a material with excellent electronic conductivity, heat resistance, oxidation resistance, and corrosion resistance. For example, ferritic stainless steel, austenitic stainless steel, or a nickel-based alloy is preferably used. In particular, an alloy containing chromium is preferably used. In this embodiment, the first plate-shaped body 1 uses an Fe-Cr-based alloy containing 18% by mass or more and 25% by mass or less of Cr, but particularly preferred are an Fe-Cr-based alloy containing 0.05% by mass or more of Mn, an Fe-Cr-based alloy containing 0.15% by mass or more and 1.0% by mass or less of Ti, an Fe-Cr-based alloy containing 0.15% by mass or more and 1.0% by mass or less of Zr, an Fe-Cr-based alloy containing Ti and Zr in which the total content of Ti and Zr is 0.15% by mass or more and 1.0% by mass or less, and an Fe-Cr-based alloy containing 0.10% by mass or more and 1.0% by mass or less of Cu.

[0129] The second plate-like body 2 is superimposed on the first plate-like body 1 and integrated with it by welding the peripheral edge portion 1a to form the plate-like support body 10 (see FIGS. 10 to 17). The second plate-like body 2 may be divided into multiple pieces relative to the first plate-like body 1, or conversely, the first plate-like body 1 may be divided into multiple pieces relative to the second plate-like body 2. Furthermore, when integrating them, other means such as adhesion or fitting can be used instead of welding, and they may be integrated at a portion other than the peripheral edge portion 1a as long as the internal flow path can be formed separately from the outside.

[0130] The first plate-like body 1 has a gas flow-permitting portion 1A formed by a large number of through-holes 11 that penetrate from the front surface to the back surface (see FIGS. 13 to 17). The through-holes 11 can be formed in the first plate-like body 1 by laser processing, for example. The through-holes 11 have the function of allowing gas to pass from the back surface to the front surface of the first plate-like body 1. The gas flow-permitting portion 1A is preferably provided in an area of ​​the first plate-like body 1 that is smaller than the area where the electrode layer 31 is provided.

[0131] A metal oxide layer 12 (see FIG. 18 , described later) is provided on the surface of the first plate-shaped body 1 as a diffusion-suppressing layer. That is, the diffusion-suppressing layer is formed between the first plate-shaped body 1 and the electrode layer 31 (described later). The metal oxide layer 12 is provided not only on the surface exposed to the outside of the first plate-shaped body 1 but also on the contact surface (interface) with the electrode layer 31. It can also be provided on the inner surface of the through-hole 11. This metal oxide layer 12 can suppress interdiffusion of elements between the first plate-shaped body 1 and the electrode layer 31. For example, if ferritic stainless steel containing chromium is used for the first plate-shaped body 1, the metal oxide layer 12 is mainly composed of chromium oxide. The metal oxide layer 12, which is mainly composed of chromium oxide, suppresses the diffusion of chromium atoms and the like from the first plate-shaped body 1 into the electrode layer 31 and the electrolyte layer 32. The thickness of the metal oxide layer 12 may be any thickness that achieves both high diffusion prevention performance and low electrical resistance. The metal oxide layer 12 can be formed by various methods, but a method of oxidizing the surface of the first plate-like body 1 to form a metal oxide is preferably used. The metal oxide layer 12 may also be formed on the surface of the first plate-like body 1 by a spray coating method (such as thermal spraying, aerosol deposition, aerosol gas deposition, powder jet deposition, particle jet deposition, or cold spray), a PVD method such as sputtering or PLD, or a CVD method, or by plating and oxidation treatment. Furthermore, the metal oxide layer 12 may contain a highly conductive spinel phase.

[0132] When ferritic stainless steel is used for the first plate 1, its thermal expansion coefficient is similar to that of YSZ (yttria-stabilized zirconia) and GDC (gadolinium-doped ceria, also known as CGO), which are materials for the electrode layer 31 and the electrolyte layer 32. Therefore, the electrochemical element A is less susceptible to damage even when subjected to repeated low- and high-temperature cycles. This is preferable because it allows for an electrochemical element A with excellent long-term durability. The first plate 1 has multiple through-holes 11 extending from the front surface to the back surface. For example, the through-holes 11 can be formed in the first plate 1 by mechanical, chemical, or optical drilling. The through-holes 11 allow gas to pass from the back surface of the first plate 1 to the front surface. Porous metal can also be used to impart gas permeability to the first plate 1. For example, the first plate 1 can be made of sintered metal, foam metal, or the like.

[0133] The second plate-like body 2 is formed in a corrugated shape in a region facing the gas flow permitting portion 1A of the first plate-like body 1, forming an internal flow path A1 with multiple sub-flow paths A11, A11 ... extending from one end side to the other end side (see FIGS. 9 and 13). The second plate-like body 2 is also formed in a corrugated shape on both its front and back sides, and the surface opposite to the surface defining the internal flow path A1 is electrically connected to the electrochemical reaction portion 3 of the adjacent electrochemical element A, and a passage formed near the contact point between the corrugated second plate-like body 2 and the first plate-like body 1 functions as the flow portion A2. A plurality of these sub-flow paths A11 are provided in parallel along the long sides of the rectangular plate-like support body 10, and form the internal flow path A1 extending from the supply path 4 at one end to the discharge path 5 at the other end. The connection between the first through-portion 41 and the internal flow path A1 bulges downward from the contact portion with the first plate-like body 1 and includes a distribution portion A12 that distributes the first gas supplied from the first through-portion 41 to each of the sub-flow paths A11 (see FIG. 9 ), and the connection between the second through-portion 51 and the internal flow path A1 bulges downward from the contact portion with the first plate-like body 1 and includes a confluence portion A13 that collects the first gas that has flowed through each of the sub-flow paths A11 and leads it to the second through-portion 51 (see FIGS. 9 , 11 , 12 , 14 to 17 ; it should be understood that the supply path 4 and the discharge path 5 are symmetrical and have the same structure). The material of the second plate-like body 2 is preferably a heat-resistant metal, and is more preferably the same material as the first plate-like body 1 from the viewpoints of reducing the thermal expansion difference with the first plate-like body 1 and ensuring the reliability of joinability such as welding.

[0134] The plate-like support 10 (an example of a metal support) consisting of the first plate-like body 1 and the second plate-like body 2 described above has an electrode layer 31, an electrolyte layer 32, a counter electrode layer 33, and the like formed on its upper surface. That is, the electrode layer 31, the electrolyte layer 32, the counter electrode layer 33, and the like are supported on the plate-like support 10, thereby realizing an electrochemical element A that is strong and has excellent reliability and durability. In addition, a metallic plate-like support 10 is preferable because it is easy to process. Furthermore, since a high-strength plate-like support 10 can be produced even when an inexpensive metal is used for the plate-like support 10, it is possible to form the expensive electrode layer 31, the electrolyte layer 32, and the like into thin layers, which is preferable because it allows for a low-cost electrochemical element A with reduced material and processing costs.

[0135] (Electrochemical reaction section) (Electrode layer) As shown in FIGS. 13 to 18, the electrode layer 31 can be provided as a thin layer on the front surface of the first plate-like body 1 in an area larger than the area where the through holes 11 are provided. When the electrode layer 31 is a thin layer, its thickness can be, for example, about 1 μm to 100 μm, preferably 5 μm to 50 μm. Such a thickness makes it possible to reduce the amount of expensive electrode layer material used, thereby reducing costs, while ensuring sufficient electrode performance. The entire area where the through holes 11 are provided is covered with the electrode layer 31. In other words, the through holes 11 are formed inside the area of ​​the first plate-like body 1 where the electrode layer 31 is formed. In other words, all of the through holes 11 are provided facing the electrode layer 31.

[0136] The electrode layer 31 has a plurality of pores inside and on the surface thereof to provide gas permeability. That is, the electrode layer 31 is formed as a porous layer. The electrode layer 31 is formed, for example, so that its density is 30% or more and less than 80%. The size of the pores can be appropriately selected so that the electrochemical reaction proceeds smoothly. Note that density is the proportion of the space occupied by the material constituting the layer, and can be expressed as (1 - porosity), and is equivalent to the relative density.

[0137] Examples of materials that can be used for the electrode layer 31 include composites such as NiO-GDC, Ni-GDC, NiO-YSZ, Ni-YSZ, CuO-CeO, and Cu-CeO. In these examples, GDC, YSZ, and CeO can be referred to as aggregates of the composites. The electrode layer 31 is preferably formed by a low-temperature firing method (e.g., a wet method using firing in a low-temperature range without firing at a high temperature above 1100°C), a spray coating method (e.g., thermal spraying, aerosol deposition, aerosol gas deposition, powder jet deposition, particle jet deposition, cold spray, etc.), a PVD method (e.g., sputtering, pulsed laser deposition, etc.), or a CVD method. These processes that can be used in a low-temperature range can provide a good electrode layer 31 without firing at a high temperature above 1100°C. This is preferable because it prevents damage to the first plate-like body 1 and suppresses interdiffusion of elements between the first plate-like body 1 and the electrode layer 31, resulting in a highly durable electrochemical device A. Furthermore, using a low-temperature firing method is even more preferable because it makes it easier to handle the raw materials.

[0138] (middle class) The intermediate layer 34 can be formed as a thin layer on the electrode layer 31, covering the electrode layer 31. When the intermediate layer 34 is a thin layer, its thickness can be, for example, about 1 μm to 100 μm, preferably about 2 μm to 50 μm, and more preferably about 4 μm to 25 μm. This thickness reduces the amount of expensive material used for the intermediate layer 34, thereby reducing costs, while ensuring sufficient performance. Examples of materials that can be used for the intermediate layer 34 include YSZ (yttria-stabilized zirconia), SSZ (scandium-stabilized zirconia), GDC (gadolinium-doped ceria), YDC (yttrium-doped ceria), and SDC (samarium-doped ceria). Ceria-based ceramics are particularly preferred.

[0139] The intermediate layer 34 is preferably formed by a low-temperature firing method (e.g., a wet method using firing at a low temperature without firing at a high temperature above 1100°C), a spray coating method (thermal spraying, aerosol deposition, aerosol gas deposition, powder jet deposition, particle jet deposition, cold spray, etc.), a PVD method (sputtering, pulsed laser deposition, etc.), a CVD method, etc. These film formation processes that can be used in a low-temperature range can obtain the intermediate layer 34 without firing at a high temperature above 1100°C, for example. This can suppress interdiffusion of elements between the first plate-like body 1 and the electrode layer 31 without damaging the first plate-like body 1, thereby achieving an electrochemical device A with excellent durability. Furthermore, using a low-temperature firing method is more preferable because it facilitates handling of raw materials.

[0140] The intermediate layer 34 preferably has oxygen ion (oxide ion) conductivity. Furthermore, it is more preferable that the intermediate layer 34 has mixed conductivity of oxygen ions (oxide ions) and electrons. The intermediate layer 34 having these properties is suitable for application to the electrochemical device A.

[0141] (electrolyte layer) As shown in FIGS. 13 to 18, the electrolyte layer 32 is formed as a thin layer on the intermediate layer 34, covering the electrode layer 31 and the intermediate layer 34. Alternatively, the electrolyte layer 32 may be formed as a thin film having a thickness of 10 μm or less. Specifically, the electrolyte layer 32 is provided across (straddles) the intermediate layer 34 and the first plate-like body 1. By configuring the electrolyte layer 32 in this way and joining the electrolyte layer 32 to the first plate-like body 1, the electrochemical element as a whole can be made to have excellent robustness.

[0142] 13, the electrolyte layer 32 is provided on the front surface of the first plate 1 in an area larger than the area in which the through-holes 11 are provided. In other words, the through-holes 11 are formed inside the area in the first plate 1 in which the electrolyte layer 32 is formed.

[0143] Furthermore, gas leakage from the electrode layer 31 and the intermediate layer (not shown) can be suppressed around the electrolyte layer 32. Specifically, when the electrochemical device A is used as a component of an SOFC, gas is supplied to the electrode layer 31 from the back side of the first plate 1 through the through-holes 11 during operation of the SOFC. Gas leakage can be suppressed in the area where the electrolyte layer 32 contacts the first plate 1 without providing a separate member such as a gasket. Note that, although the electrolyte layer 32 completely covers the periphery of the electrode layer 31 in this embodiment, a configuration in which the electrolyte layer 32 is provided on top of the electrode layer 31 and the intermediate layer 34 and a gasket or the like is provided around the periphery may also be adopted.

[0144] The electrolyte layer 32 can be made of oxygen ion-conducting electrolyte materials such as YSZ (yttria-stabilized zirconia), SSZ (scandium-stabilized zirconia), GDC (gadolinium-doped ceria), YDC (yttrium-doped ceria), SDC (samarium-doped ceria), or LSGM (strontium-magnesium-doped lanthanum gallate), or hydrogen ion-conducting electrolyte materials such as perovskite-type oxides. Zirconia-based ceramics are particularly suitable. Using zirconia-based ceramics for the electrolyte layer 32 can increase the operating temperature of an SOFC using electrochemical element A compared to ceria-based ceramics and various hydrogen ion-conducting materials. For example, when electrochemical element A is used in an SOFC, if a material such as YSZ that can exhibit high electrolyte performance even at high temperatures of approximately 650°C or higher is used as the material for electrolyte layer 32, and if a hydrocarbon-based raw fuel such as city gas or LPG is used as the raw fuel for the system and the raw fuel is converted into SOFC anode gas by steam reforming or the like, a highly efficient SOFC system can be constructed in which the heat generated in the SOFC cell stack is used to reform the raw fuel gas.

[0145] The electrolyte layer 32 is preferably formed by a low-temperature firing method (e.g., a wet method using firing at a low temperature without firing at a high temperature above 1100°C), a spray coating method (such as thermal spraying, aerosol deposition, aerosol gas deposition, powder jet deposition, particle jet deposition, or cold spray), a PVD method (such as sputtering or pulsed laser deposition), or a CVD (chemical vapor deposition) method. These low-temperature film-forming processes can produce a dense electrolyte layer 32 with high airtightness and gas barrier properties without firing at a high temperature above 1100°C. This can prevent damage to the first plate-like body 1 and inhibit interdiffusion of elements between the first plate-like body 1 and the electrode layer 31, resulting in an electrochemical device A with excellent performance and durability. Low-temperature firing methods and spray coating methods are particularly preferred because they allow for low-cost devices. Furthermore, spray coating is more preferable because it is easy to obtain a dense electrolyte layer that is airtight and has high gas barrier properties at low temperatures.

[0146] The electrolyte layer 32 is densely structured to prevent gas leakage of anode gas and cathode gas and to exhibit high ionic conductivity. The density of the electrolyte layer 32 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. When the electrolyte layer 32 is a uniform layer, the density is preferably 95% or more, and even more preferably 98% or more. Furthermore, when the electrolyte layer 32 is structured in a multi-layer structure, it is preferable that at least a portion of the layers includes a layer with a density of 98% or more (a dense electrolyte layer), and more preferably a layer with a density of 99% or more (a dense electrolyte layer). When such a dense electrolyte layer is included as part of the electrolyte layer, it is easier to form an electrolyte layer that is dense and has high airtightness and gas barrier properties, even when the electrolyte layer is structured in a multi-layer structure.

[0147] (Reaction prevention layer) The reaction prevention layer 35 can be formed as a thin layer on the electrolyte layer 32. When the layer is thin, its thickness can be, for example, about 1 μm to 100 μm, preferably about 2 μm to 50 μm, and more preferably about 3 μm to 15 μm. This thickness reduces the amount of expensive reaction prevention layer material used, thereby reducing costs and ensuring sufficient performance. The material for the reaction prevention layer can be any material that can prevent a reaction between the components of the electrolyte layer 32 and the components of the counter electrode layer 33, such as a ceria-based material. A material containing at least one element selected from the group consisting of Sm, Gd, and Y is preferably used as the material for the reaction prevention layer 35. It is preferable that the material contains at least one element selected from the group consisting of Sm, Gd, and Y, and that the total content of these elements is 1.0% by mass or more and 10% by mass or less. By providing the reaction prevention layer 35 between the electrolyte layer 32 and the counter electrode layer 33, the reaction between the constituent materials of the counter electrode layer 33 and the electrolyte layer 32 is effectively suppressed, thereby improving the long-term stability of the performance of the electrochemical device A. The reaction prevention layer 35 is preferably formed using a method that allows it to be formed at a processing temperature of 1100°C or less, because this prevents damage to the first plate-like body 1 and also suppresses interdiffusion of elements between the first plate-like body 1 and the electrode layer 31, resulting in an electrochemical device A with excellent performance and durability. For example, the reaction prevention layer 35 can be formed by a low-temperature firing method (e.g., a wet method that uses a firing process at a low temperature that does not involve firing at a high temperature above 1100°C), a spray coating method (such as a thermal spraying method, an aerosol deposition method, an aerosol gas deposition method, a powder jet deposition method, a particle jet deposition method, or a cold spray method), a PVD method (such as a sputtering method or a pulsed laser deposition method), or a CVD method. In particular, low-temperature firing or spray coating is preferred because it allows for low-cost elements to be realized. Furthermore, low-temperature firing is even more preferred because it allows for easy handling of raw materials.

[0148] (Counter electrode layer) As shown in FIGS. 13 to 18, the counter electrode layer 33 can be formed as a thin layer on the electrolyte layer 32 or the reaction prevention layer 35. When the counter electrode layer 33 is formed as a thin layer, its thickness can be, for example, approximately 1 μm to 100 μm, preferably 5 μm to 50 μm. This thickness reduces the amount of expensive counter electrode layer material used, thereby reducing costs, while ensuring sufficient electrode performance. Examples of materials that can be used for the counter electrode layer 33 include composite oxides such as LSCF and LSM, ceria-based oxides, and mixtures thereof. It is particularly preferable that the counter electrode layer 33 contains a perovskite-type oxide containing two or more elements selected from the group consisting of La, Sr, Sm, Mn, Co, and Fe. The counter electrode layer 33 formed using these materials functions as a cathode.

[0149] The counter electrode layer 33 is preferably formed using a method capable of forming the counter electrode layer at a processing temperature of 1100°C or less, since this method can prevent damage to the first plate 1 and suppress interdiffusion of elements between the first plate 1 and the electrode layer 31, thereby achieving an electrochemical device A with excellent performance and durability. For example, a low-temperature firing method (e.g., a wet method using a firing process at a low temperature without firing at a high temperature above 1100°C), a spray coating method (thermal spraying, aerosol deposition, aerosol gas deposition, powder jet deposition, particle jet deposition, cold spray, etc.), a PDV method (sputtering, pulsed laser deposition, etc.), a CVD method, etc., can be used. Low-temperature firing methods and spray coating methods are particularly preferred, since they allow for low-cost devices. Furthermore, low-temperature firing methods are even more preferred, since they facilitate the handling of raw materials.

[0150] By configuring the electrochemical reaction unit 3 in this way, when the electrochemical reaction unit 3 is made to function as a fuel cell (electrochemical power generation cell), the electrochemical element A can be used as a power generation cell of a solid oxide fuel cell. For example, a fuel gas containing hydrogen as a first gas is supplied to the electrode layer 31 through the through-holes 11 from the back surface of the first plate-like body 1, and air as a second gas is supplied to the counter electrode layer 33, which is the counter electrode of the electrode layer 31, and the temperature is maintained at an operating temperature of, for example, about 700°C. Then, oxygen O2 contained in the air is converted into electrons e in the counter electrode layer 33. - reacts with oxygen ions O 2- The oxygen ions O 2- The hydrogen H2 contained in the supplied fuel gas moves through the electrolyte layer 32 to the electrode layer 31. In the electrode layer 31, the hydrogen H2 contained in the supplied fuel gas is converted into oxygen ions O 2- reacts with water H2O and electrons e - is generated. When an electrolyte material that conducts hydrogen ions is used for the electrolyte layer 32, hydrogen H2 contained in the fuel gas flowing through the electrode layer 31 is converted into electrons e - releases hydrogen ions H + The hydrogen ions H + moves through the electrolyte layer 32 to the counter electrode layer 33. At the counter electrode layer 33, oxygen O2 and hydrogen ions H + , electronic e - reacts to produce water H2O. The above reaction generates an electromotive force as an electrochemical output between the electrode layer 31 and the counter electrode layer 33. In this case, the electrode layer 31 functions as the fuel electrode (anode) of the fuel cell, and the counter electrode layer 33 functions as the air electrode (cathode).

[0151] 13 to 17, in this embodiment, the electrochemical reaction unit 3 includes an intermediate layer 34 between the electrode layer 31 and the electrolyte layer 32, as shown in Fig. 18. Furthermore, a reaction prevention layer 35 is provided between the electrolyte layer 32 and the counter electrode layer 33.

[0152] (Electrochemical element stack) 4, the electrochemical element stack S has a plurality of electrochemical elements A, and the electrochemical elements A are stacked such that, with respect to adjacent electrochemical elements A, the plate-like support 10 constituting one electrochemical element A faces the plate-like support 10 constituting the other electrochemical element A, the outer surface of a second plate-like body 2 other than the first plate-like body 1 on which the electrochemical reaction unit 3 of the plate-like support 10 constituting one electrochemical element A is electrically connected to the outer surface of the first plate-like body 1 of the plate-like support 10 constituting the other electrochemical element A, and a flow section A2 through which the second gas flows is formed along the two adjacent outer surfaces. To achieve the electrical connection, methods such as simply contacting the electrically conductive surface portions or applying a surface pressure to the contact surface or interposing a highly electrically conductive material to reduce contact resistance can be used. Specifically, each rectangular electrochemical element is aligned with the first through-hole 41 at one end and the second through-hole 51 at the other end, with the electrochemical reaction part of each electrochemical element facing upward, and is stacked with a first annular packing material 42 and a second annular packing material 52 interposed between each first through-hole 41 and second through-hole 51, thereby achieving the above-mentioned configuration.

[0153] The plate-like support 10 is provided with first penetrations 41 at one longitudinal end of the rectangular plate-like support 10, which form a supply path 4 for supplying a first gas, which is one of a reducing component gas and an oxidizing component gas, to the internal flow path A1 from the outside in the surface penetration direction, and first annular packing materials 42 are provided within the flow path A2 as annular packing materials that separate the first penetrations 41, which are formed on both outer surfaces of the plate-like support 10, from the flow path A2, and the first penetrations 41 and the first annular packing materials 42 form the supply path 4 for supplying the first gas to the internal flow path A1. Incidentally, an annular bulge a is provided on the side of the first plate-like body 1 opposite to the internal flow path A1 around the portion of the first plate-like body 1 that contacts the first annular packing material 42, to facilitate positioning of the first annular packing material 42 in the direction along the surface of the first plate-like body 1.

[0154] In addition, the plate-shaped support body 10 has a second through-portion 51 on the other end side which forms an exhaust path 5 for discharging the first gas that has flowed through the internal flow path A1 outward in the direction penetrating the surface of the plate-shaped support body 10, and the second through-portion 51 is configured to allow the first gas to flow while being partitioned from the second gas, and within the flow-through portion A2, it has a second annular packing material 52 as an annular packing material that partitions the second through-portions 51 formed on both outer surfaces of the plate-shaped support body 10 from the flow-through portion A2, and the second through-portion 51 and the second annular packing material 52 form an exhaust path 5 for discharging the first gas that has flowed through the internal flow path A1.

[0155] (7) Annular packing material Next, the first and second annular packing materials 42, 52 will be described.

[0156] 19 and 20, each annular packing material 42, 52 in this embodiment includes a metal material 42 a, 52 a made of a thermally expandable material and an insulating metal oxide layer 42 b, 52 b. A through-hole 42 c, 52 c is formed inside the metal material 42 a, 52 a and the metal oxide layer 42 b, 52 b, which are annular in top view. The sealing area sealed by the metal material 42 a, 52 a and the metal oxide layer 42 b, 52 b is annular. Each annular packing material 42, 52 communicates the first and second through-holes 41, 51 with each other through the through-hole 42 c, 52 c, and seals between adjacent electrochemical elements A with the sealing area.

[0157] As shown in FIG. 2, the annular packing materials 42, 52 of this embodiment are made of metal materials 42a, 52a which are circular flat plates, and the entire surfaces of the metal materials 42a, 52a, including the upper and lower surfaces, are covered with metal oxide layers 42b, 52b.

[0158] The planar outer shape of the annular packing materials 42, 52 is not limited to a circular ring, and may be any shape as long as it is annular. The annular shape includes any shape such as a circle, an ellipse, a square, a polygon, etc.

[0159] Examples of constituent materials of the metal materials 42a, 52a include ferritic stainless steel, austenitic stainless steel, Inconel, copper, Invar, etc. The metal materials 42a, 52a preferably include at least one selected from the group consisting of ferritic stainless steel, austenitic stainless steel, Inconel, copper, and Invar.

[0160] 21, the metal materials 42a, 52a may be bimetals 420a, 520a formed by bonding, for example, by rolling, metal 421a, 521a having a small thermal expansion coefficient and metal 422a, 522a having a large thermal expansion coefficient. The bimetals 420a, 520a are formed by bonding together plates of two types of metal with different thermal expansion coefficients, and change into a specific shape in response to temperature changes.

[0161] When bimetals 420a, 520a are used as the metal materials 42a, 52a, it is desirable that the bimetals 420a, 520a are configured so that as the temperature of the bimetals 420a, 520a themselves rises, they change from a flat plate shape shown in FIG. 21 to an arc-shaped warp as shown in FIG. 22, increasing the width in the thickness direction (T>t). For example, invar material (thermal expansion coefficient 0.2×10) is used as the metal 421a, 521a having a small thermal expansion coefficient. -5 / ℃), and SUS316 (thermal expansion coefficient 1.8×10 -5 / °C) is used, and if the bimetals 420a and 520a have t of 0.5 mm, when the temperature of the bimetals 420a and 520a themselves rises to 700°C, T becomes 0.68 mm.

[0162] The longitudinal cross-sectional shape of the metal material 42a, 52a of the annular packing materials 42, 52 may be a flat plate shape (see FIG. 20), a wave shape (see FIG. 23), a triangular shape (see FIG. 24), a circular shape (see FIG. 25), an oval shape (not shown), a sawtooth shape (see FIG. 26), O-shape Shape (see Figure 27) 、D It is preferable that the casing has one or more of the following shapes (see FIG. 27).

[0163] 28, the vertical cross-sectional shape of the metal materials 42a, 52a is preferably a ring shape with a closed space (internal space) 42d, 52d on the inside. That is, the metal materials 42a, 52a are formed in a ring shape around the entire circumference in a vertical cross-sectional view, and a closed space 42d, 52d that is partitioned from the outside is formed in a sealed state inside the ring-shaped portion. Note that the closed space 42d, 52d is formed in a ring shape around the entire circumference of the metal materials 42a, 52a in a top view. Gas or liquid is sealed within the closed spaces 42d, 52d, and when exposed to a high-temperature environment, the gas or liquid sealed within the closed spaces 42d, 52d thermally expands, further promoting the expansion of the metal materials 42a, 52a, thereby increasing the surface pressure, thereby achieving even higher sealing performance. The vertical cross-sectional shapes of the metal materials 42a and 52a shown in FIG. 、D However, the cross-sectional shape is not limited to this, and the cross-sectional shape may be, for example, a circle, an ellipse, a triangle, a rectangle, or the like.

[0164] Examples of materials constituting the metal oxide layers 42b, 52b include alumina, silica, magnesium oxide, iron oxide, chromium oxide, manganese oxide, etc. The metal oxide layers 42b, 52b preferably contain at least one selected from the group consisting of alumina, silica, magnesium oxide, iron oxide, chromium oxide, and manganese oxide.

[0165] When the metal material 42a, 52a has a flat, corrugated, sawtooth, or other shape, the metal oxide layer 42b, 52b may be provided on at least one of the upper and lower surfaces of the metal material 42a, 52a. Even if the metal material 42a, 52a has another shape, as long as its insulation is ensured, the metal oxide layer 42b, 52b does not necessarily need to cover the entire metal material 42a, 52a, and may be provided on at least one side in the thickness direction of the metal material 42a, 52a.

[0166] The annular packing materials 42, 52 according to the present embodiment can be produced by a known lamination method for laminating a metal oxide on a metal material 42 a, 52 a. For example, the surface of the metal material 42 a, 52 a can be etched to deposit an oxide on the surface of the metal material 42 a, 52 a, thereby laminating the metal oxide layer 42 b, 52 b, or the metal oxide can be applied, bonded, baked, spray-coated, or thermally sprayed onto the surface of the metal material 42 a, 52 a, thereby laminating the metal oxide layer 42 b, 52 b. Note that it is preferable to laminate the metal oxide layers 42b, 52b on the metal materials 42a, 52a by, for example, a low-temperature firing method (a wet method using firing treatment in a low-temperature range that does not involve firing treatment in a high-temperature range exceeding 1100°C), a spray coating method (such as thermal spraying, aerosol deposition, aerosol gas deposition, powder jet deposition, particle jet deposition, or cold spray), a PVD method (such as sputtering or pulsed laser deposition), or a CVD method, since this method can suppress deterioration of the metal materials 42a, 52a.

[0167] In an SOFC, there is a large temperature difference between when power is being generated and when it is not, and therefore the electrochemical element stack S in the SOFC is exposed to an environment where the temperature changes, including high temperatures. In this embodiment, as described above, the planar members 220 made of a thermal expansion member are disposed on the upper and lower planar surfaces of the electrochemical element stack S, and are subjected to a predetermined clamping pressure from the upper and lower plates 230 to elastically support the electrochemical element stack S. The surface pressure of the annular packing materials 42, 52 acts on the plate-like support 10, ensuring sealing. However, repeated temperature changes may, for example, reduce the elasticity of the metal oxide layers 42b, 52b, resulting in the formation of a small gap between the annular packing materials 42, 52 and the plate-like support 10.

[0168] With the annular packing materials 42, 52, even if the elasticity of the metal oxide layers 42b, 52b decreases, creating a small gap between the annular packing materials 42, 52 and the plate-like support 10, the expansion tension of the metal materials 42a, 52a increases the surface pressure during power generation of the SOFC, providing high sealing performance. Therefore, sufficient sealing performance is ensured between the inside (i.e., the supply path 4 and the discharge path 5) and outside (i.e., the flow section A2) of the metal materials 42a, 52a and the metal oxide layers 42b, 52b between adjacent plate-like support members 10. Furthermore, the metal materials 42a, 52a are resistant to hardening even at high temperatures, allowing for long-term use. Furthermore, the annular packing materials 42, 52, including the metal oxide layers 42b, 52b, maintain insulation between adjacent plate-like support members 10 (i.e., between the electrochemical elements A).

[0169] Furthermore, if the first plate-like body 1 and the second plate-like body 2 of the plate-like support body 10 are formed from materials having different thermal expansion coefficients from the thermal expansion coefficients of the metal materials 42a and 52a, when exposed to high temperatures, the surface pressure can be increased by utilizing the thermal expansion force generated by the difference in thermal expansion between the first plate-like body 1 and the second plate-like body 2 and the metal materials 42a and 52a, resulting in even higher sealing performance. Specifically, the thermal expansion coefficient of the metal materials 42a, 52a can be made larger than that of the first plate-shaped body 1 and the second plate-shaped body 2, or the thermal expansion coefficient of the metal materials 42a, 52a can be made smaller than that of the first plate-shaped body 1 and the second plate-shaped body 2. More specifically, by using ferritic stainless steel for the first plate-shaped body 1 and the second plate-shaped body 2 and austenitic stainless steel for the metal materials 42a, 52a, the thermal expansion coefficient of the metal materials 42a, 52a can be made larger than that of the first plate-shaped body 1 and the second plate-shaped body 2. In this case, when exposed to high temperatures, the metal materials 42a, 52a thermally expand larger than that of the first plate-shaped body 1 and the second plate-shaped body 2, and the surface pressure of the metal materials 42a, 52a against the first plate-shaped body 1 and the second plate-shaped body 2 increases, thereby achieving higher sealing performance.

[0170] (8) Energy systems, electrochemical devices Next, the energy system and the electrochemical device will be described with reference to FIG. The energy system Z includes an electrochemical device 100 and a heat exchanger 190 as a waste heat utilization section that reuses heat discharged from the electrochemical device 100. The electrochemical device 100 has an electrochemical module M, a fuel supply module, and an inverter (an example of a power converter) 104 as an output unit 8 that extracts electric power from the electrochemical module M. The fuel supply module is composed of a desulfurizer 101, a vaporizer 106, and a reformer 102, and has a fuel supply unit 103 that supplies a fuel gas containing a reducing component to the electrochemical module M. In this case, the reformer 102 serves as the fuel converter.

[0171] Specifically, the electrochemical device 100 includes a desulfurizer 101, a reforming water tank 105, a vaporizer 106, a reformer 102, a blower 107, a combustion unit 108, an inverter 104, a control unit 110, and an electrochemical module M.

[0172] The desulfurizer 101 removes (desulfurizes) sulfur compounds contained in hydrocarbon raw fuel such as city gas. When sulfur compounds are contained in the raw fuel, the provision of the desulfurizer 101 can suppress adverse effects of the sulfur compounds on the reformer 102 or the electrochemical device A. The vaporizer 106 generates steam from reforming water supplied from the reforming water tank 105. The reformer 102 uses the steam generated in the vaporizer 106 to steam reform the raw fuel desulfurized in the desulfurizer 101, generating a reformed gas containing hydrogen.

[0173] The electrochemical module M generates electricity by electrochemical reaction using the reformed gas supplied from the reformer 102 and the air supplied from the blower 107. The combustion section 108 mixes the reaction exhaust gas discharged from the electrochemical module M with air and combusts combustible components in the reaction exhaust gas.

[0174] The inverter 104 adjusts the output power of the electrochemical module M to the same voltage and frequency as the power received from a commercial grid (not shown). The control unit 110 controls the operation of the electrochemical device 100 and the energy system Z.

[0175] The reformer 102 performs a reforming process on the raw fuel using the combustion heat generated by the combustion of the reaction exhaust gas in the combustion section 108 .

[0176] The raw fuel is supplied to the desulfurizer 101 through a raw fuel supply path 112 by operation of a booster pump 111. The reforming water in the reforming water tank 105 is supplied to the vaporizer 106 through a reforming water supply path 114 by operation of a reforming water pump 113. The raw fuel supply path 112 merges with the reforming water supply path 114 at a location downstream of the desulfurizer 101, and the reforming water and raw fuel that have merged outside the container 200 are supplied to the vaporizer 106.

[0177] The reforming water is vaporized in the vaporizer 106 to become water vapor. The raw fuel containing water vapor produced in the vaporizer 106 is supplied to the reformer 102 through a water vapor-containing raw fuel supply path 115. The raw fuel is steam reformed in the reformer 102 to produce a reformed gas (a first gas having a reducing component) mainly composed of hydrogen gas. The reformed gas produced in the reformer 102 is supplied to the electrochemical module M through a fuel supply unit 103.

[0178] The reaction exhaust gas is combusted in the combustion section 108 to become a combustion exhaust gas, which is sent from the combustion exhaust gas discharge path 116 to the heat exchanger 190. A combustion catalyst section 117 (e.g., a platinum-based catalyst) is arranged in the combustion exhaust gas discharge path 116, and reduces the carbon monoxide, hydrogen, and other reducing components contained in the combustion exhaust gas by combustion.

[0179] The heat exchanger 190 exchanges heat between the combustion exhaust gas generated by combustion in the combustion unit 108 and the supplied cold water to generate hot water. In other words, the heat exchanger 190 operates as a waste heat utilization unit that reuses the heat discharged from the electrochemical device 100.

[0180] Instead of the exhaust heat utilization section, a reaction exhaust gas utilization section may be provided that utilizes the reaction exhaust gas discharged (without being combusted) from the electrochemical module M. Also, at least a portion of the reaction exhaust gas circulating from the first gas discharge section 62 to the outside of the container 200 may be recycled by joining it with any of the locations 100, 101, 103, 106, 112, 113, and 115 in FIG. 29. The reaction exhaust gas contains residual hydrogen gas that was not used in the reaction in the electrochemical device A. In the reaction exhaust gas utilization section, the residual hydrogen gas is utilized for heat utilization by combustion or for power generation using a fuel cell or the like, thereby making effective use of energy.

[0181] [Modification of annular packing material] The following describes modified examples of the first and second annular packing materials 42, 52. Note that the same components as those in the above-described embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0182] As shown in FIG. 32, in the annular packing materials 42, 52 of this example, the metal oxide layers 42b, 52b are laminated along the surfaces of the metal materials 42a, 52a. In other words, the thickness of the metal oxide layers 42b, 52b is uniform. In the illustrated example, the longitudinal cross-sectional shape of the metal materials 42a, 52a is corrugated. The cross-sectional shape (surface shape) of the metal oxide layers 42b, 52b is also corrugated. The longitudinal cross-sectional shape of the annular packing materials 42, 52 is also corrugated. In other words, the longitudinal cross-sectional shape of the annular packing materials may be the same as the longitudinal cross-sectional shape of the metal materials 42a, 52a.

[0183] The cross-sectional shape of the metal material 42a, 52a may be other shapes (for example, a triangular shape (see FIG. 24), a saw blade shape (see FIG. 26), O-shape Shape (see Figure 27) 、D In the case of the annular packing material 42, 52 having a square shape (see FIG. 27), the thickness of the metal oxide layers 42b, 52b may be uniform, and the vertical cross-sectional shape of the metal materials 42a, 52a and the vertical cross-sectional shape of the annular packing materials 42, 52 may be the same.

[0184] 24 and 26-28, the thickness of the metal oxide layers 42b, 52b may not be uniform. The cross-sectional shape of the annular packing material may be different from that of the metal materials 42a, 52a.

[0185] [Modifications of Electrochemical Element Stack and Electrochemical Module] In the electrochemical element laminate S and the electrochemical module M, the first and second annular packing materials 42, 52 may be disposed between the plate-shaped support 10 (an example of a metal substrate) and the annular packing materials 42, 52 with ceramic paste applied to at least a portion of their surfaces. The ceramic paste may be applied to the entire surfaces of the annular packing materials 42, 52. The ceramic paste may be applied only to the front or back surfaces of the annular packing materials 42, 52.

[0186] The ceramic paste is a paste that improves the airtightness (sealing property) of a joint, such as a gasket paste. The ceramic paste is made into a paste form by adding a viscosity adjuster to a ceramic as the main component. The main component of the ceramic paste may be a metal oxide or an inorganic polymer. The main component of the ceramic paste may be mica, silica, or alumina. The ceramic paste may be water-soluble.

[0187] It should be noted that the electrochemical elements A do not have to be stacked in the electrochemical module M. In other words, a plurality of electrochemical elements A may be arranged in a cluster in the electrochemical module M. The electrochemical elements A do not have to be stacked in the electrochemical element stack S. In other words, a plurality of electrochemical elements A may be arranged in a cluster in the electrochemical element stack S. In this case, the electrochemical element stack S may be referred to as an "electrochemical element assembly."

[0188] [Gas leak measurement test results] The results of a measurement test of the amount of gas leakage when the above-described annular packing materials 42, 52 and ceramic paste were used will be described with reference to the table of FIG.

[0189] A sealed container with a volume of 1 liter and one opening is created. The opening is sealed with test packing material. Nitrogen is supplied to the sealed container to increase the internal pressure. When the internal pressure reaches the test pressure, the nitrogen supply is stopped and the pressure is measured after 10 minutes. The amount of gas leakage is calculated from the difference between the test pressure and the measured pressure. The test was conducted at room temperature and at 750°C (Experimental Example 2 only). The test pressure was approximately 23 kPa, which is approximately 10 times the normal operating pressure of the electrochemical element stack S and electrochemical module M.

[0190] The following two types of test packing were used:

[0191] [Experimental Example 1] The test packing in Experimental Example 1 is a vermiculite-glass composite packing, which is a commercially available product.

[0192] [Experimental Example 2] The test packing in Experimental Example 2 was made by applying a ceramic paste containing mica as the main component to the annular packing material shown in Figure 32. The metal material of the annular packing material was a ring-shaped corrugated stainless steel plate made of SUS430. The thickness of the metal material was 0.1 mm. The metal oxide layer of the annular packing material was alumina. The thickness of the metal oxide layer was 1 μm to 2 μm. The metal oxide layer was layered on the surface of the metal material by spray coating.

[0193] The results of the gas leakage measurement test are shown in Figure 33. At room temperature, the gas leakage rate for the test packing of Experimental Example 1 was 2.1 ml / min. In contrast, the gas leakage rate for the test packing of Experimental Example 2 was 0.0 ml / min, below the measurement limit. At 750°C, the gas leakage rate for the test packing of Experimental Example 2 was 0.0 ml / min, below the measurement limit. Because the gas leakage rate at room temperature was large, the test at 750°C for the test packing of Experimental Example 1 was omitted.

[0194] The experimental results confirmed that by using the test packing of Experimental Example 2, the amount of gas leakage can be extremely reduced both at room temperature and at a high temperature of 750°C. The test packing of Experimental Example 2 is an example of the present invention. The test packing of Experimental Example 1 is a comparative example.

[0195] Other Embodiments The configurations disclosed in the above-described embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, as long as no contradictions arise. Furthermore, the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited to these, and can be modified as appropriate within the scope that does not deviate from the purpose of the present invention.

[0196] (1) In the above embodiment, the flat plate member 220 is applied to the electrochemical module M in which the electrochemical element A is an SOFC. However, the above flat plate member 220 can also be applied to an SOEC (Solid Oxide Electrolyzer Cell), a secondary battery, etc.

[0197] (2) In the above embodiment, the electrochemical element A is used in a solid oxide fuel cell as the electrochemical device 100, but the electrochemical element A can also be used in a solid oxide electrolysis cell, an oxygen sensor using a solid oxide, etc. Furthermore, the electrochemical element A can be used alone, not limited to being used in combination as the electrochemical element stack S or the electrochemical module M. That is, in the above embodiment, a configuration capable of improving the efficiency of converting chemical energy such as fuel into electrical energy has been described. That is, in the above embodiment, the electrochemical device A and the electrochemical module M are operated as a fuel cell, and hydrogen gas is circulated through the electrode layer 31, and oxygen gas is circulated through the counter electrode layer 33. Then, oxygen molecules O2 are converted into electrons e in the counter electrode layer 33. - reacts with oxygen ions O 2- The oxygen ions O 2- moves through the electrolyte layer 32 to the electrode layer 31. In the electrode layer 31, hydrogen molecules H2 are converted into oxygen ions O 2-reacts with water H2O and electrons e - The above reaction generates an electromotive force between the electrode layer 31 and the counter electrode layer 33, generating electricity. On the other hand, when the electrochemical device A and the electrochemical module M are operated as an electrolysis cell, a gas containing water vapor and carbon dioxide is passed through the electrode layer 31, and a voltage is applied between the electrode layer 31 and the counter electrode layer 33. Then, electrons e - reacts with water molecules H2O and carbon dioxide molecules CO2 to produce hydrogen molecules H2, carbon monoxide CO, and oxygen ions O 2- Oxygen ions O 2- moves through the electrolyte layer 32 to the counter electrode layer 33. In the counter electrode layer 33, oxygen ions O 2- releases electrons and becomes oxygen molecules O2. Through the above reaction, water molecules H2O are electrolyzed into hydrogen H2 and oxygen O2, and when gas containing carbon dioxide molecules CO2 is circulated, it is electrolyzed into carbon monoxide CO and oxygen O2. When gas containing water vapor and carbon dioxide molecules CO2 is circulated, a fuel converter 25 (Fig. 31) can be provided to synthesize various compounds such as hydrocarbons from the hydrogen and carbon monoxide produced by the electrolysis in the electrochemical element A and electrochemical module M. The hydrocarbons produced by the fuel converter 25 can be extracted from the system / device by a fuel supply unit (not shown) and used separately as fuel. The hydrogen and carbon monoxide can also be converted into chemical raw materials by the fuel converter 25 and used.

[0198] FIG. 31 shows an example of an energy system Z and an electrochemical device 100 in which the electrochemical reaction unit 3 operates as an electrolysis cell (an electrolysis reaction occurs in the electrochemical element A). In this system, supplied water and carbon dioxide are electrolyzed in the electrochemical reaction unit 3 to produce hydrogen, carbon monoxide, and other substances. Furthermore, hydrocarbons and other substances are synthesized in the fuel converter 25. Energy efficiency can be improved by configuring the heat exchanger 24 in FIG. 31 to operate as a waste heat utilization unit that exchanges heat generated by the reaction in the fuel converter 25 with water to vaporize it, and the heat exchanger 23 in FIG. 31 to operate as a waste heat utilization unit that exchanges heat generated by the electrochemical element A with water vapor and carbon dioxide to preheat them. Furthermore, the power converter 93 supplies power to the electrochemical element A. As a result, the electrochemical element A functions as an electrolysis cell, as described above. Therefore, the above configuration can provide an electrochemical device 100, an energy system Z, and the like that can improve the efficiency of converting electrical energy into chemical energy, such as fuel.

[0199] (3) In the above embodiment, the electrode layer 31 is made of a composite material such as NiO-GDC, Ni-GDC, NiO-YSZ, Ni-YSZ, CuO-CeO, or Cu-CeO, and the counter electrode layer 33 is made of a composite oxide such as LSCF or LSM. The electrochemical element A configured in this manner can be used as a solid oxide fuel cell by supplying hydrogen gas to the electrode layer 31 to serve as a fuel electrode (anode) and air to the counter electrode layer 33 to serve as an air electrode (cathode). This configuration can also be modified to configure the electrochemical element A so that the electrode layer 31 serves as an air electrode and the counter electrode layer 33 serves as a fuel electrode. That is, the electrode layer 31 is made of a composite oxide such as LSCF or LSM, and the counter electrode layer 33 is made of a composite material such as NiO-GDC, Ni-GDC, NiO-YSZ, Ni-YSZ, CuO-CeO, or Cu-CeO. In the electrochemical element A configured in this manner, air can be supplied to the electrode layer 31 to make it an air electrode, and hydrogen gas can be supplied to the counter electrode layer 33 to make it a fuel electrode, and the electrochemical element A can be used as a solid oxide fuel cell.

[0200] (4) In the above embodiment, the electrode layer 31 is disposed between the first plate 1 and the electrolyte layer 32, and the counter electrode layer 33 is disposed on the opposite side of the electrolyte layer 32 from the first plate 1. A configuration in which the electrode layer 31 and the counter electrode layer 33 are disposed in reverse is also possible. That is, a configuration in which the counter electrode layer 33 is disposed between the first plate 1 and the electrolyte layer 32, and the electrode layer 31 is disposed on the opposite side of the electrolyte layer 32 from the first plate 1 is also possible. In this case, the supply of gas to the electrochemical device A must also be changed. That is, various configurations can be adopted for the order of the electrode layer 31 and the counter electrode layer 33 and whether the first gas or the second gas is one or the other of the reducing component gas and the oxidizing component gas, as long as the first gas and the second gas are supplied to the electrode layer 31 and the counter electrode layer 33 in a form that allows them to react appropriately.

[0201] (5) In the above embodiment, the electrochemical reaction unit 3 is provided on the side of the first plate-like body 1 opposite the second plate-like body 2, covering the gas flow-permitting portion 1A. However, the electrochemical reaction unit 3 may be provided on the side of the first plate-like body 1 facing the second plate-like body 2. In other words, the present invention is valid even if the electrochemical reaction unit 3 is configured to be disposed in the internal flow path A1.

[0202] (6) In the above embodiment, the first through portion 41 and the second through portion 51 are provided in pairs at both ends of the rectangular plate-like support body, but they are not limited to being provided at both ends, and two or more pairs may be provided. Moreover, the first through portion 41 and the second through portion 51 do not have to be provided in pairs. Therefore, one or more first through portion 41 and one or more second through portion 51 may be provided. Furthermore, the plate-like support body is not limited to a rectangular shape, and various shapes such as a square shape and a circular shape may be adopted.

[0203] (7) In the above, the plate-like support 10 is composed of a first plate-like body 1 and a second plate-like body 2. Here, the first plate-like body 1 and the second plate-like body 2 may be composed of separate plate-like bodies, or may be composed of a single plate-like body as shown in FIG. 30. In the case of FIG. 30, the first plate-like body 1 and the second plate-like body 2 are overlapped by bending the single plate-like body. Then, the first plate-like body 1 and the second plate-like body 2 are integrated by welding or the like at the peripheral edge portion 1a. Note that the first plate-like body 1 and the second plate-like body 2 may be composed of a single seamless plate-like body, or may be formed as shown in FIG. 30 by bending a single plate-like body. As will be described later, the second plate-like body 2 may be made up of one member or two or more members. Similarly, the first plate-like body 1 may be made up of one member or two or more members.

[0204] (8) The second plate-like body 2, together with the first plate-like body 1, forms an internal flow path A1. The internal flow path A1 has a distribution section A12, multiple sub-flow paths A11, and a junction section A13. As shown in FIG. 9, the first gas supplied to the distribution section A12 is distributed to each of the multiple sub-flow paths A11 and then merges at the junction section A13 at the outlets of the multiple sub-flow paths A11. Thus, the first gas flows along the gas flow direction from the distribution section A12 to the junction section A13. The multiple sub-flow paths A11 are formed by forming the portions of the second plate-like body 2 other than the distribution section A12 to the junction section A13 into a corrugated plate shape. As shown in FIG. 13, the multiple sub-flow paths A11 are formed into a corrugated plate shape in cross section in a flow intersecting direction that intersects the gas flow direction of the first gas. The multiple sub-flow paths A11 are formed by extending corrugated plates along the gas flow direction shown in FIG. The plurality of sub-flow paths A11 may be formed from a series of corrugated plates between the distribution section A12 and the confluence section A13, or may be composed of two or more corrugated plates. The plurality of sub-flow paths A11 may be formed, for example, from two or more corrugated plates separated along the gas flow direction, or from two or more corrugated plates separated along the cross-flow direction.

[0205] 13, the sub-flow paths A11 are formed in a wave-like shape by repeatedly forming peaks and valleys of the same shape. However, the second plate-like body 2 may have plate-like portions in the region where the sub-flow paths A11 are formed. For example, the sub-flow paths A11 may be formed by alternately forming plate-like portions and protruding portions. The protruding portions may be portions through which a fluid such as the first gas flows.

[0206] (9) The portions of the second plate-like body 2 corresponding to the plurality of sub-flow paths A11 do not need to be entirely corrugated, but may be at least partially corrugated. For example, between the distribution section A12 and the merging section A13, part of the second plate-like body 2 in the gas flow direction may be flat and the rest may be corrugated. Furthermore, part of the second plate-like body 2 in the cross-flow direction may be flat and the rest may be corrugated.

[0207] (10) In the above embodiment, the electrochemical device includes an electrochemical module M including a plurality of electrochemical elements A. However, the electrochemical device of the above embodiment can also be applied to a configuration including one electrochemical element.

[0208] Furthermore, the configurations disclosed in the above embodiments can be applied in combination with configurations disclosed in other embodiments as long as no contradictions arise, and the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited to these, and can be modified as appropriate within the scope that does not deviate from the purpose of the present invention. [Industrial Applicability]

[0209] The present invention can be suitably used in technical fields relating to annular packing materials, electrochemical modules, electrochemical devices, energy systems, solid oxide fuel cells, and solid oxide electrolysis cells. [Explanation of symbols]

[0210] 25 Fuel Converter 31 Electrode layer 32 Electrolyte layer 33 Counter electrode layer 42 First annular packing material 52 Second annular packing material 42a,52a Metal materials 420a, 520a Bimetal 421a,521a Metals with low thermal expansion coefficients 422a,522a Metals with large thermal expansion coefficients 42b,52b Metal oxide layer 42c,52c through hole 42d,52d Closed space 93 Power Converter 100 Electrochemical Device 101 Desulfurizer 102 Reformer 103 Fuel supply section 104 Inverter 200 containers 220 Flat plate members 230 Plate A. Electrochemical element M Electrochemistry Module S Electrochemical element stack Z Energy System

Claims

1. An annular packing material that electrically insulates adjacent members, a metal material made of a thermal expansion member that expands due to heat, and an insulating metal oxide layer on at least one side in a thickness direction of the metal material, wherein a through hole is formed inside the annularly formed metal material and the metal oxide layer; The annular packing material has a cross-sectional shape of the metal material that is one or more of a triangular shape, a sawtooth shape, a wave shape, a circular shape, an elliptical shape, an O-shape, and a D-shape.

2. 2. The annular packing material according to claim 1, wherein the metal oxide layer contains at least one of alumina, silica, magnesium oxide, iron oxide, chromium oxide, and manganese oxide.

3. 3. The annular packing material according to claim 1, wherein the metallic material includes at least one of ferritic stainless steel, austenitic stainless steel, Inconel, copper, and Invar.

4. 4. The annular packing material according to claim 1, wherein the metal material has a cross-sectional shape of an annulus having a closed space therein.

5. 4. The annular packing material according to claim 1, wherein the metallic material is a bimetal.

6. 6. An electrochemical module comprising a plurality of electrochemical elements, each of which includes an electrolyte layer and a first electrode and a second electrode disposed on either side of the electrolyte layer, stacked with metal substrates interposed between the electrochemical elements, and wherein the annular gasket material according to any one of claims 1 to 5 is disposed between adjacent metal substrates.

7. 7. The electrochemical module according to claim 6, wherein the thermal expansion coefficient of the metallic material is different from the thermal expansion coefficient of the metallic substrate.

8. 8. The electrochemical module according to claim 6, wherein the annular packing material is disposed between the metal substrate and the annular packing material with a ceramic paste applied to at least a portion of the surface of the annular packing material.

9. The electrochemical module of claim 8 , wherein the ceramic paste contains mica.

10. 10. An electrochemical device comprising at least the electrochemical module according to claim 6, and a fuel converter that generates reducing components to be supplied to the electrochemical module or converts gas containing reducing components generated in the electrochemical module.

11. 10. An electrochemical device comprising: the electrochemical module according to claim 6; and a power converter that extracts electric power from the electrochemical module or passes electric power to the electrochemical module.

12. 12. An energy system comprising: the electrochemical device according to claim 10; and a waste heat utilization section that reuses heat discharged from the electrochemical device.

13. A solid oxide fuel cell comprising the electrochemical module according to any one of claims 6 to 9, wherein a power generation reaction occurs in the electrochemical module.

14. A solid oxide electrolysis cell comprising the electrochemical module according to any one of claims 6 to 9, wherein an electrolytic reaction occurs in the electrochemical module.

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