JP7645683B2 - Annular spacer, electrochemical element, electrochemical module, electrochemical device, energy system, solid oxide fuel cell, and solid oxide electrolysis cell - Google Patents

Description

The present invention relates to an annular spacer, an electrochemical element, an electrochemical module, an electrochemical device, an energy system, a solid oxide fuel cell, and a solid oxide electrolysis cell.

Conventionally, electrochemical element stacks constituting electrochemical devices such as fuel cells (electrochemical power generation cells) and electrolysis cells have been configured by airtightly stacking a number of substrates, including metal substrates that have a gas permeable region and cover the gas permeable region to form an electrochemical reaction section, and metal substrates that function as spacers and separators, as shown in Patent Document 1. Then, an air flow path for air (oxidizing component gas) and a fuel gas flow path for fuel gas (reducing component gas) are defined along both sides of the metal substrate (electrochemical element) that has an electrochemical reaction section, and air and fuel gas are circulated through each flow path. In other words, a plurality of electrochemical elements are stacked and integrally formed as an electrochemical module. As a result, electrochemical output such as electricity is generated from the reaction between air and fuel gas in the electrochemical reaction section.

Special table 2017-508254 publication

However, because an electrochemical module like this forms the air flow path and the fuel gas flow path by stacking multiple substrates, it is necessary to securely seal and fix multiple metal substrates. Therefore, to produce such an electrochemical module, a great deal of labor and meticulous care are required to reliably and securely fix the substrates. This results in a large increase in the production costs of such electrochemical modules, and a decrease in the reliability of the electrochemical modules produced (such as the airtightness between the metal substrates and the reliability of the electrical connections).

In view of the above circumstances, the present invention aims to provide a means for facilitating the creation of an electrochemical module in which multiple electrochemical elements are arranged in an assembled state, and to provide electrochemical elements having a structure that is easy to handle when producing the electrochemical module. It is a further aim to provide electrochemical devices and energy systems, solid oxide fuel cells, and solid oxide electrolysis cells that utilize electrochemical modules at low cost.

As a means for solving the above-mentioned problems, the annular spacer of the present invention is a plate-shaped annular spacer having a through hole extending from the front to the back, and is provided with a flow path for allowing gas to flow from the space inside the through hole to the space outside the annular spacer when sandwiched between other members , and is characterized in that in the central portion of the annular spacer, at least one of the front and back surfaces has a flange-shaped flange portion that protrudes in the front-to-back direction beyond the surrounding area so as to form a peripheral wall of the through hole .

According to this configuration, when the annular spacer is sandwiched between other members, gas can flow from the space inside the through hole to the space outside the annular spacer. Such an annular spacer can be suitably applied to the plate-like support of an electrochemical element. For example, the plate-like support may be constructed by opposing two plates, and the space between the two plates may be used as a gas flow path (internal flow path). In this case, various advantages are obtained by arranging the annular spacer in a state where it is sandwiched between the two plates. First, the rigidity of the plate-like support can be increased. When an electrochemical module is created, a plurality of electrochemical elements are assembled, and a force is applied in the assembly direction. The presence of the annular spacer can suppress deformation of the plate-like elements and maintain the shape of the internal flow path. In addition, the through hole and flow path of the annular spacer can be used to supply gas to the internal flow path of the plate-like support. Therefore, the annular spacer can easily create an electrochemical module in which a plurality of electrochemical elements are arranged in an assembled state. In other words, the annular spacer can provide an electrochemical element having a structure that is easy to handle when creating an electrochemical module.
In addition, in this configuration, the annular spacer has a flange-shaped portion on at least one of the front and back surfaces at the center thereof, which protrudes in the front-back direction from the periphery so as to form a peripheral wall of the through hole. With this, when the annular spacer is sandwiched between two plate-like bodies, the annular spacer can be positioned relative to the plate-like bodies, for example, by providing a flange portion at the through hole provided in one of the plate-like bodies.

In the present invention, it is preferable that the base has a flat base and a protrusion on at least one of the front and back surfaces of the base that protrudes in the front-back direction beyond the surrounding area, the space around the protrusion functions as the flow path , and the flange portion is provided in the center of the base .

This configuration allows for a simple flow path in the annular spacer.

In the present invention, it is preferable that the nozzle is configured to include a plurality of first portions arranged with gaps in the circumferential direction and a second portion connecting the first portions, the gaps functioning as the flow path and the second portions serving as the flange portion .

This configuration allows for a simple flow path in the annular spacer.

In the present invention, it is preferable that the electrode be formed from an electrically conductive material.

According to this configuration, when the annular spacer is sandwiched between two other components, the two components can be electrically connected through the annular spacer. In other words, when the annular spacer is used as a plate-like support for an electrochemical element, the electrical conductivity of the plate-like support can be improved.

In the present invention, it is preferable that the material includes one or more of ferritic stainless steel, austenitic stainless steel, Inconel, copper, and Invar material.

This configuration allows the annular spacer to be produced inexpensively using readily available materials.

As a means for solving the above-mentioned problems, the electrochemical element of the present invention is an electrochemical element comprising an electrolyte layer, a first electrode and a second electrode respectively disposed on both sides of the electrolyte layer, and a plate-shaped support for supporting the electrolyte layer, the first electrode, and the second electrode, wherein the plate-shaped support comprises a conductive first plate-shaped body, a conductive second plate-shaped body, and an internal flow path formed between the opposing surfaces of the first plate-shaped body and the second plate-shaped body, and the above-mentioned annular spacer is disposed between the first plate-shaped body and the second plate-shaped body.

According to this configuration, since the annular spacer is disposed between the first plate-like body and the second plate-like body, deformation of the first plate-like body and the second plate-like body can be suppressed, and the shape of the internal flow path can be maintained. In other words, the rigidity of the plate-like support can be increased. In addition, the through holes and flow paths of the annular spacer can be used to supply gas to the internal flow path of the plate-like support. Therefore, it is possible to easily create an electrochemical module in which multiple electrochemical elements are arranged in a grouped state. In other words, the annular spacer can provide electrochemical elements with a structure that is easy to handle when fabricating an electrochemical module.

In the present invention, it is preferable that at least one of the first plate-like body and the second plate-like body has a through-hole that forms a gas supply path to the internal flow path, and the annular spacer is arranged so that the through-hole overlaps with the through-hole of the annular spacer when viewed in the thickness direction of the plate-like support body.

With this configuration, gas from the through-hole can be supplied to the internal flow path between the first plate-like body and the second plate-like body through the through-hole and flow path of the annular spacer.

As a means for solving the above-mentioned problems, the electrochemical module of the present invention is characterized in that a plurality of the above-mentioned electrochemical elements are arranged in a cluster.

With this configuration, multiple electrochemical elements as described above are arranged in a cluster, making it possible to obtain a compact, high-performance electrochemical module with excellent strength and reliability while keeping material and processing costs down.

As a means for solving the above-mentioned problems, the electrochemical device of the present invention is characterized by having at least the above-mentioned electrochemical element or the above-mentioned electrochemical module, and a fuel converter that generates a reducing component to be supplied to the electrochemical element or the electrochemical module, or that converts a gas containing a reducing component generated by the electrochemical element or the electrochemical module.

According to this configuration, when the electrochemical element or electrochemical module is operated as a fuel cell, it can be configured to generate hydrogen using a fuel converter such as a reformer based on 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 element or 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 element or electrochemical module is operated as an electrolysis cell, a gas containing water vapor or carbon dioxide is circulated through the electrode layer, and a voltage is applied between the electrode layer and the counter electrode layer. Then, in the electrode layer, the electrons e ^- react with the water molecules H ₂ O and the carbon dioxide molecules CO ₂ to become hydrogen molecules H ₂ , carbon monoxide CO, and oxygen ions O ^{2 -} . The generated oxygen ions O ^{2 -} move through the electrolyte layer to the counter electrode layer. Then, in the counter electrode layer, the oxygen ions O ^{2 -} release electrons to become oxygen molecules O _2. By the above reaction, when a gas containing water vapor is circulated, the water molecules H ₂ O are decomposed into hydrogen H ₂ and oxygen O ₂ , and when a gas containing carbon dioxide molecules CO ₂ is circulated, the water molecules H 2 O are electrolyzed into carbon monoxide CO and oxygen O ₂ .
Therefore, when a 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 hydrogen and carbon monoxide generated in the electrochemical element or electrochemical module by the above-mentioned electrolysis. This makes it possible to circulate the hydrocarbons generated by the fuel converter to the electrochemical element or electrochemical module, or to extract them from the system/apparatus and use them as fuel or chemical raw materials separately.

As a means for solving the above-mentioned problems, the electrochemical device of the present invention is characterized by having at least the above-mentioned electrochemical element or the above-mentioned electrochemical module, and a power converter that extracts power from the electrochemical element or the electrochemical module or passes power to the electrochemical element or the electrochemical module.

According to this configuration, the power converter extracts power generated by the electrochemical element or electrochemical module, or passes power to the electrochemical element or electrochemical module. As a result, the electrochemical element or electrochemical module functions as a fuel cell or an electrolysis cell. Thus, according to the above configuration, it is possible to provide an electrochemical element or the like 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, when an inverter is used as a power converter, the electric output obtained from an electrochemical element or electrochemical module having excellent durability, reliability, and performance can be boosted or DC can be converted to AC by the inverter, so that the electric output obtained from the electrochemical element or electrochemical module can be easily utilized, which is preferable. In addition, when used for electrolysis, it is preferable because an electrochemical device can be constructed that can obtain DC from an AC power source and supply DC power to an electrochemical element or electrochemical module.

As a means for solving the above-mentioned problems, the energy system of the present invention is characterized by having the above-mentioned electrochemical device and a waste heat utilization section that reuses the heat discharged from the electrochemical device.

This configuration has an electrochemical device and a waste heat utilization section that reuses the heat discharged from the electrochemical device, making it possible to realize an energy system that is durable, reliable, and has excellent performance, as well as excellent energy efficiency. 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 using the combustion heat of unused fuel gas discharged from the electrochemical device.

As a means for solving the above-mentioned problems, the solid oxide fuel cell of the present invention is characterized by comprising the above-mentioned electrochemical element, and causing a power generation reaction in the electrochemical element.

According to this configuration, a power generation reaction can be performed as a solid oxide fuel cell equipped with an electrochemical element having excellent durability, reliability, and performance, so that a highly durable and high-performance solid oxide fuel cell can be obtained. In addition, a solid oxide fuel cell that can be operated at a temperature range of 650°C or more during rated operation is more preferable because it can construct a system in which the heat required for converting raw fuel into hydrogen can be supplied by the exhaust heat of the fuel cell in a fuel cell system that uses hydrocarbon gas such as city gas as raw fuel, thereby improving the power generation efficiency of the fuel cell system. In addition, a solid oxide fuel cell that is operated at a temperature range of 900°C or less during rated operation is more preferable because it enhances the effect of suppressing Cr volatilization from the metal-supported electrochemical element, and a solid oxide fuel cell that is operated at a temperature range of 850°C or less during rated operation is even more preferable because it further enhances the effect of suppressing Cr volatilization.

As a means for solving the above-mentioned problems, the solid oxide electrolysis cell of the present invention is characterized by comprising the above-mentioned electrochemical element and causing an electrolytic reaction in the electrochemical element.

This configuration allows gas to be generated through an electrolytic reaction as a solid oxide electrolysis cell equipped with an electrochemical element that is highly durable, reliable, and high performance, making it possible to obtain a highly durable, high-performance solid oxide electrolysis cell.

Schematic diagram of an electrochemical device Cross-sectional view taken along line II-II in FIG. III-III view in FIG. IV-IV cross-sectional view in FIG. VV cross-sectional view in FIG. VI-VI cross-sectional view in FIG. 1. Cross-sectional view taken along the line VII-VII in FIG. Cross-sectional view taken along line VIII-VIII in FIG. IX-IX cross-sectional view in FIG. Enlarged view of the electrochemical reaction section Schematic diagram of the electrochemical module Energy system diagram FIG. 1 is an explanatory diagram of an electrochemical module according to another embodiment. Schematic diagram of alternative energy systems A perspective view of an annular spacer Plan view of an annular spacer Cross-section of an electrochemical device A perspective view of an annular spacer Plan view of an annular spacer Cross-section of an electrochemical device

The annular spacer, electrochemical element, electrochemical device, energy system, solid oxide fuel cell, and solid oxide electrolysis cell of the present invention are described below. Note that although preferred examples are described below, these examples are described to more specifically illustrate the present invention, and various modifications are possible within the scope of the present invention, and the present invention is not limited to the following description. Note that when describing the positional relationship of layers, for example, the side of the electrolyte layer as viewed from the electrode layer is called "upper" or "upper side", and the side of the first plate-like body is called "lower" or "lower side", etc.

(Electrochemical element)
As shown in Figures 1 to 9, the electrochemical element A comprises a plate-like support 10 having an internal flow path A1 formed between 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 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 in a state covering all or a part of the gas flow-permitting portion 1A (see Figures 5 to 9). Furthermore, the plate-shaped support 10 has a first through portion 41 at one end forming a supply passage 4 through which a first gas, which is one of a reducing component gas such as a fuel gas and an oxidizing component gas such as air, flows from the outside in the surface-penetrating direction into the internal flow passage A1, and a second through portion 51 at the other end forming an exhaust passage 5 through which the first gas that has passed through the internal flow passage A1 flows outward in the surface-penetrating direction of the plate-shaped support 10 (see Figures 1, 3, 8, and 9; it will also be understood that the supply passages 4, etc. and the exhaust passages 5, etc. are symmetrical and have similar structures).

(Plate-shaped support)
The first plate-like body 1 supports the electrochemical reaction section 3 having the electrode layer 31, the electrolyte layer 32, and the counter electrode layer 33, and plays a role in maintaining the strength of the electrochemical element A. The material of the first plate-like body 1 is a material having excellent electronic conductivity, heat resistance, oxidation resistance, and corrosion resistance. For example, ferritic stainless steel, austenitic stainless steel, nickel-based alloys, etc. are used. In particular, alloys containing chromium are preferably used. In this embodiment, the first plate-like body 1 uses an Fe—Cr-based alloy containing 18% by mass or more and 25% by mass or less of Cr. However, 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.

The second plate-like body 2 is overlapped with the first plate-like body 1 and integrated with it by welding the peripheral portion 1a to form the plate-like support body 10 (see Figures 2 to 9). 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. In addition, when integrating, other means such as adhesion or fitting can be used instead of welding, and as long as the internal flow path can be formed separately from the outside, integration may be possible at a portion other than the peripheral portion 1a.

The first plate-like body 1 is generally plate-shaped. It has a gas flow-permitting portion 1A having a large number of through holes 11 that penetrate the front surface and the back surface (see Figures 5 to 9). For example, the through holes 11 can be provided in the first plate-like body 1 by laser processing or the like. The through holes 11 have the function of allowing gas to pass from the back surface of the first plate-like body 1 to the front surface. It is preferable that the gas flow-permitting portion 1A is provided in an area of the first plate-like body 1 that is smaller than the area in which the electrode layer 31 is provided.

The first plate-shaped body 1 has a metal oxide layer 12 (see FIG. 10, described later) on its surface as a diffusion suppression layer. That is, the diffusion suppression 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, when ferritic stainless steel containing chromium is used as the first plate-shaped body 1, the metal oxide layer 12 is mainly chromium oxide. The metal oxide layer 12, which is mainly composed of chromium oxide, suppresses the diffusion of chromium atoms, etc. of 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 can achieve 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 a thermal spray 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 PLD method, a CVD method, or by plating and oxidation treatment. Furthermore, the metal oxide layer 12 may contain a highly conductive spinel phase, etc.

When a ferritic stainless steel material is used as the first plate-like body 1, the thermal expansion coefficient is close to that of YSZ (yttria-stabilized zirconia) and GDC (gadolinium-doped ceria, also called CGO), which are materials for the electrode layer 31 and the electrolyte layer 32. Therefore, the electrochemical element A is less likely to be damaged even when a low-temperature and high-temperature temperature cycle is repeated. This is preferable because it allows the electrochemical element A to have excellent long-term durability. The first plate-like body 1 has a plurality of through holes 11 that penetrate the front surface and the back surface. For example, the through holes 11 can be formed in the first plate-like body 1 by mechanical, chemical, or optical drilling. The through holes 11 have the function of allowing gas to pass from the back surface of the first plate-like body 1 to the front surface. It is also possible to use a porous metal to give the first plate-like body 1 gas permeability. For example, the first plate-like body 1 can be made of a sintered metal, a foamed metal, or the like.

The second plate-like body 2 is formed in a corrugated shape to form an internal flow path A1 having a plurality of sub-flow paths A11, A11 ... from one end side to the other end side in the region facing the gas flow permitting portion 1A of the first plate-like body 1 (see Figs. 1 and 5). In addition, both the front and back sides of the second plate-like body 2 are formed in a corrugated shape, and the surface opposite to the surface that defines the internal flow path A1 is electrically connected to the electrochemical reaction portion 3 of the adjacent electrochemical element A, and the passage formed near the portion where the corrugated second plate-like body 2 contacts the first plate-like body 1 functions as the flow portion A2. A plurality of sub-flow paths A11 are provided in parallel along the long side of the plate-like support body 10 formed in a rectangular shape, and constitute the internal flow path A1 from the supply path 4 provided at one end to the discharge path 5 provided at the other end. In addition, the connection between the first through-portion 41 and the internal flow passage A1 is formed by bulging downward from the contact portion with the first plate-like body 1, and is provided with a distribution portion A12 that distributes the first gas flowing from the first through-portion 41 to each of the sub-flow passages A11 (see FIG. 1), and the connection between the second through-portion 51 and the internal flow passage A1 is formed by bulging downward from the contact portion with the first plate-like body 1, and is provided with a junction portion A13 that collects the first gas that has flowed through each of the sub-flow passages A11 and leads it to the second through-portion 51 (see FIGS. 1, 3, 4, 6 to 9, and it is understood that the supply passage 4 and the discharge passage 5 are symmetrical and have the same structure). In addition, 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 viewpoint of reducing the thermal expansion difference with the first plate-like body 1 and ensuring the reliability of joining such as welding.

(Electrochemical reaction section)
(Electrode layer)
As shown in Figs. 5 to 10, the electrode layer 31 can be provided in 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 provided as a thin layer, the thickness can be, for example, about 1 µm to 100 µm, preferably 5 µm to 50 µm. With such a thickness, it is possible to ensure sufficient electrode performance while reducing the amount of expensive electrode layer material used to reduce costs. The entire area where the through holes 11 are provided is covered with the electrode layer 31. That is, the through holes 11 are formed inside the area where the electrode layer 31 is formed in the first plate-like body 1. In other words, all the through holes 11 are provided facing the electrode layer 31.

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 the density is the ratio of the space occupied by the material constituting the layer, and can be expressed as (1-porosity), and is equivalent to the relative density.

The material of the electrode layer 31 may be, for example, a composite material such as NiO-GDC, Ni-GDC, NiO-YSZ, Ni-YSZ, CuO _{- CeO2} , or Cu _{- CeO2} . In these examples, GDC, YSZ, and _CeO2 may be called aggregates of the composite material. The electrode layer 31 is preferably formed by a low-temperature firing method (for example, a wet method using firing in a low-temperature range without firing in a high-temperature range higher than 1100°C), a spray coating method (such as a thermal spray 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. By using these processes that can be used in a low-temperature range, a good electrode layer 31 can be obtained without firing in a high-temperature range higher than 1100°C. Therefore, it is preferable because it is possible to realize an electrochemical element A having excellent durability without damaging the first plate-like body 1 and suppressing interdiffusion of elements between the first plate-like body 1 and the electrode layer 31. Furthermore, it is even more preferable to use a low-temperature firing method because it makes it easier to handle the raw materials.

(Middle class)
The intermediate layer 34 can be formed as a thin layer on the electrode layer 31 while covering the electrode layer 31. When the intermediate layer 34 is a thin layer, the 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. With such a thickness, it is possible to reduce the amount of expensive material used for the intermediate layer 34, thereby reducing costs, while ensuring sufficient performance. As the material for the intermediate layer 34, for example, YSZ (yttria-stabilized zirconia), SSZ (scandium-stabilized zirconia), GDC (gadolinium-doped ceria), YDC (yttrium-doped ceria), SDC (samarium-doped ceria), etc. can be used. In particular, ceria-based ceramics are preferably used.

The intermediate layer 34 is preferably formed by a low-temperature firing method (e.g., a wet method using firing in a low-temperature range without firing in a high-temperature range higher than 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, pulse 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 in a high-temperature range higher than 1100°C, for example. Therefore, it is possible to suppress interdiffusion of elements between the first plate-like body 1 and the electrode layer 31 without damaging the first plate-like body 1, and to realize an electrochemical element A with excellent durability. In addition, using a low-temperature firing method is even more preferable because it makes it easier to handle the raw materials.

It is preferable that the intermediate layer 34 has oxygen ion (oxide ion) conductivity. It is even more preferable that the intermediate layer 34 has mixed conductivity of oxygen ions (oxide ions) and electrons. An intermediate layer having these properties is suitable for application to the electrochemical element A.

The electrode layer 31 may also be configured so that the content ratio, density, and strength of the aggregate of the cermet material increase continuously from the lower side to the upper side of the electrode layer 31. In this case, the electrode layer 31 does not need to have regions that can be clearly distinguished as layers. However, even in this case, it is possible to increase the content ratio, density, strength, etc. of the aggregate of the cermet material in the portion of the electrode layer 31 adjacent to the electrolyte layer 32 (upper portion) compared to the portion of the electrode layer 31 adjacent to the first plate-like body 1 (lower portion).

(Electrolyte layer)
5 to 10, the electrolyte layer 32 is formed in a thin layer state on the electrode layer 31 and the intermediate layer 34 while covering the intermediate layer. Alternatively, the electrolyte layer 32 may be formed in a thin film state having a thickness of 10 μm or less. More specifically, the electrolyte layer 32 is provided across (straddling) the intermediate layer 34 and the first plate-like body 1. By configuring 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.

As shown in FIG. 5, the electrolyte layer 32 is provided on the front surface of the first plate-like body 1 in an area larger than the area in which the through-hole 11 is provided. In other words, the through-hole 11 is formed inside the area in which the electrolyte layer 32 is formed in the first plate-like body 1.

In addition, gas leakage from the electrode layer 31 and the intermediate layer (not shown) can be suppressed around the electrolyte layer 32. To explain, when the electrochemical element 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-like body 1 through the through hole 11 during operation of the SOFC. In the area where the electrolyte layer 32 contacts the first plate-like body 1, gas leakage can be suppressed without providing a separate member such as a gasket. Note that, although the electrolyte layer 32 covers the entire 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 and a gasket or the like is provided around the periphery may also be used.

As the material of the electrolyte layer 32, electrolyte materials that conduct oxygen ions, such as YSZ (yttria-stabilized zirconia), SSZ (scandium-stabilized zirconia), GDC (gadolinium-doped ceria), YDC (yttrium-doped ceria), SDC (samarium-doped ceria), and LSGM (strontium-magnesium-doped lanthanum gallate), and electrolyte materials that conduct hydrogen ions, such as perovskite-type oxides, can be used. In particular, zirconia-based ceramics are preferably used. When the electrolyte layer 32 is made of zirconia-based ceramics, the operating temperature of the SOFC using the electrochemical element A can be made higher than that of ceria-based ceramics and various hydrogen ion conductive materials. For example, when electrochemical element A is used in an SOFC, a material that can exhibit high electrolyte performance even at high temperatures of 650°C or higher, such as YSZ, is used as the material for electrolyte layer 32, and a hydrocarbon-based raw fuel such as city gas or LPG is used as the raw fuel for the system. The raw fuel is converted into SOFC anode gas by steam reforming or the like, making it possible to construct a highly efficient SOFC system in which the heat generated in the SOFC cell stack is used to reform the raw fuel gas.

The electrolyte layer 32 is preferably formed by a low-temperature firing method (e.g., a wet method using firing at a low temperature range without firing at a high temperature range exceeding 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, pulse laser deposition, etc.), a CVD (chemical vapor deposition) method, etc. These film formation processes that can be used in the low temperature range can obtain an electrolyte layer 32 that is dense, airtight, and has high gas barrier properties without firing at a high temperature range exceeding 1100 ° C., for example. Therefore, damage to the first plate-like body 1 can be suppressed, and the interdiffusion of elements between the first plate-like body 1 and the electrode layer 31 can be suppressed, and an electrochemical element A with excellent performance and durability can be realized. In particular, it is preferable to use a low-temperature firing method or a spray coating method, etc., because it is possible to realize a low-cost element. Furthermore, spray coating is more preferable because it is easy to obtain a dense electrolyte layer 32 with high airtightness and gas barrier properties at low temperatures.

The electrolyte layer 32 is densely constructed to prevent gas leakage of the anode gas and the cathode gas and to exhibit high ion 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 more preferably 98% or more. When the electrolyte layer 32 is constructed in a multi-layered structure, it is preferable that at least a part of the electrolyte layer 32 includes a layer (dense electrolyte layer) having a density of 98% or more, and more preferably includes a layer (dense electrolyte layer) having a density of 99% or more. If such a dense electrolyte layer is included in a part of the electrolyte layer 32, it is easy to form an electrolyte layer 32 that is dense, airtight, and has high gas barrier properties, even when the electrolyte layer 32 is constructed in a multi-layered structure.

(Reaction prevention layer)
The reaction prevention layer 35 can be formed in a thin layer state on the electrolyte layer 32. When the reaction prevention layer 35 is a thin layer, the 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. With such a thickness, it is possible to reduce the amount of expensive reaction prevention layer material used to reduce costs while ensuring sufficient performance. The material of the reaction prevention layer may be any material that can prevent the reaction between the components of the electrolyte layer 32 and the components of the counter electrode layer 33, and for example, a ceria-based material is used. In addition, a material containing at least one element selected from the group consisting of Sm, Gd, and Y is preferably used as the material of the reaction prevention layer 35. It is preferable that the reaction prevention layer 35 contains at least one element selected from the group consisting of Sm, Gd, and Y, and the total content of these elements is 1.0 mass% or more and 10 mass% or less. By introducing the reaction prevention layer 35 between the electrolyte layer 32 and the counter electrode layer 33, the reaction between the constituent material of the counter electrode layer 33 and the constituent material of the electrolyte layer 32 is effectively suppressed, and the long-term stability of the performance of the electrochemical element A can be improved. The reaction prevention layer 35 is preferably formed by a method that can be formed at a processing temperature of 1100° C. or less, since it can suppress damage to the first plate-like body 1 and also suppress interdiffusion of elements between the first plate-like body 1 and the electrode layer 31, thereby realizing an electrochemical element A with excellent performance and durability. For example, it can be formed by a low-temperature firing method (for example, a wet method using a firing process in a low-temperature range that does not include a firing process in a high-temperature range exceeding 1100° C.), a spray coating method (a method such as a thermal spray 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 (a sputtering method, a pulsed laser deposition method, or the like), a CVD method, or the like, as appropriate. In particular, low-temperature firing or spray coating is preferable because it allows low-cost devices to be realized. Furthermore, low-temperature firing is even more preferable because it allows easy handling of raw materials.

(Counter electrode layer)
As shown in FIGS. 5 to 10, the counter electrode layer 33 can be formed in a thin layer state on the electrolyte layer 32 or the reaction prevention layer 35. When the counter electrode layer 33 is formed as a thin layer, the thickness can be, for example, about 1 μm to 100 μm, preferably 5 μm to 50 μm. With such a thickness, it is possible to ensure sufficient electrode performance while reducing the amount of expensive counter electrode layer material used to reduce costs. As the material for the counter electrode layer 33, for example, composite oxides such as LSCF and LSM, ceria-based oxides, and mixtures thereof can be used. In particular, it is 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 the above materials functions as a cathode.

The counter electrode layer 33 is preferably formed by a method capable of forming the layer at a processing temperature of 1100°C or less, since it can suppress damage to the first plate-like body 1 and also suppress interdiffusion of elements between the first plate-like body 1 and the electrode layer 31, thereby realizing an electrochemical element A with excellent performance and durability. For example, the low-temperature firing method (for example, a wet method using a firing process in a low-temperature range without firing at a high temperature range exceeding 1100°C), the spray coating method (thermal spraying method, aerosol deposition method, aerosol gas deposition method, powder jet deposition method, particle jet deposition method, cold spray method, etc.), the PDV method (sputtering method, pulse laser deposition method, etc.), the CVD method, etc. can be appropriately used. In particular, the low-temperature firing method and the spray coating method are preferable because they can realize a low-cost element. Furthermore, the low-temperature firing method is even more preferable because it makes it easier to handle the raw materials.

By configuring such an electrochemical reaction unit 3, for example, a fuel gas containing hydrogen as a first gas is circulated from the back surface of the first plate-like body 1 through the through hole 11 to the electrode layer 31, and air as a second gas is circulated to the counter electrode layer 33 which is the counter electrode of the electrode layer 31, and the operating temperature is maintained at, for example, 500°C to 900°C. Then, when an electrolyte material that conducts oxygen ions is used for the electrolyte layer 32, oxygen O ₂ contained in the air reacts with electrons e ^- in the counter electrode layer 33 to generate oxygen ions O ^2- . The oxygen ions O ^2- move through the electrolyte layer 32 to the electrode layer 31. In the electrode layer 31, hydrogen H ₂ contained in the circulated fuel gas reacts with oxygen ions O ^2- to generate water H ₂ O and electrons e ^- . When an electrolyte material that conducts hydrogen ions is used for the electrolyte layer 32, hydrogen H ₂ contained in the circulated fuel gas in the electrode layer 31 releases electrons e ^- to generate hydrogen ions H ⁺ . The hydrogen ions H ⁺ move through the electrolyte layer 32 to the counter electrode layer 33. In the counter electrode layer 33, oxygen _O2 contained in the air reacts with the hydrogen ions H ⁺ and electrons ^e- to produce water _H2O . Due to the above reaction, an electromotive force is generated 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).

Although omitted in Figs. 5 to 9, in this embodiment, as shown in Fig. 10, the electrochemical reaction unit 3 has an intermediate layer 34 between the electrode layer 31 and the electrolyte layer 32. Furthermore, a reaction prevention layer 35 is provided between the electrolyte layer 32 and the counter electrode layer 33.

(Method of manufacturing electrochemical reaction section)
Next, a method for manufacturing the electrochemical reaction section 3 will be described. Note that since the intermediate layer 34 and the reaction prevention layer 35 described below are omitted in Fig. 5 to Fig. 9, the description will be given mainly with reference to Fig. 10.

(Electrode layer formation step)
In the electrode layer forming step, the electrode layer 31 is formed in a thin film state in an area wider than the area where the through holes 11 are provided on the front surface of the first plate-like body 1. The through holes 11 of the first plate-like body 1 can be provided by laser processing or the like. As described above, the electrode layer 31 can be formed by a low-temperature firing method (a wet method in which firing is performed in a low temperature range of 1100 ° C or less), a spray coating method (a method such as a thermal spray method, an aerosol deposition method, an aerosol gas deposition method, a powder jet deposition method, a particle jet deposition method, a cold spray method, etc.), a PVD method (a sputtering method, a pulsed laser deposition method, etc.), a CVD method, etc. In any case, it is preferable to perform the method at a temperature of 1100 ° C or less in order to suppress deterioration of the first plate-like body 1.

When the electrode layer formation step is performed using a low-temperature firing method, it is specifically performed as follows. First, the material powder of the electrode layer 31 is mixed with a solvent (dispersion medium) to prepare a material paste, which is then applied to the front surface of the first plate-like body 1 and fired at 800°C to 1100°C.

(Diffusion suppression layer formation step)
During the firing process in the electrode layer formation step described above, a metal oxide layer 12 (diffusion suppression layer) is formed on the surface of the first plate-like body 1. If the firing process includes a firing process in which the firing atmosphere is under atmospheric conditions with a low oxygen partial pressure, the interdiffusion suppression effect of elements is high and a good quality metal oxide layer 12 (diffusion suppression layer) with a low resistance value is formed, which is preferable. The electrode layer formation step may include a separate diffusion suppression layer formation step, including a case where a coating method without firing is used. In either case, it is preferable to perform the process at a processing temperature of 1100° C. or less, which is capable of suppressing damage to the first plate-like body 1.

(Intermediate layer forming step)
In the intermediate layer forming step, the intermediate layer 34 is formed in a thin layer state on the electrode layer 31 so as to cover the electrode layer 31. As described above, the intermediate layer 34 can be formed by a low-temperature firing method (a wet method in which firing is performed in a low-temperature range of 1100°C or less), a spray coating method (a thermal spray method, an aerosol deposition method, an aerosol gas deposition method, a powder jet deposition method, a particle jet deposition method, a cold spray method, or the like), a PVD method (a sputtering method, a pulsed laser deposition method, or the like), a CVD method, or the like. In any case, it is preferable to perform the method at a temperature of 1100°C or less in order to suppress deterioration of the first plate-like body 1.

When the intermediate layer forming step is carried out by a low-temperature firing method, it is specifically carried out as follows.
First, the material powder of the intermediate layer 34 and a solvent (dispersion medium) are mixed to prepare a material paste, which is then applied to the front surface of the first plate-like body 1. The intermediate layer 34 is then compression molded (intermediate layer smoothing step) and fired at 1100°C or less (intermediate layer firing step). The intermediate layer 34 can be rolled by, for example, CIP (Cold Isostatic Pressing) molding, roll pressure molding, RIP (Rubber Isostatic Pressing) molding, etc. In addition, it is preferable to fire the intermediate layer 34 at a temperature of 800°C or more and 1100°C or less. This is because such a temperature makes it possible to form a high-strength intermediate layer 34 while suppressing damage and deterioration of the first plate-like body 1. In addition, it is more preferable to fire the intermediate layer 34 at 1050°C or less, and even more preferable to fire it at 1000°C or less. This is because the lower the firing temperature of the intermediate layer 34, the more the electrochemical element A can be formed while suppressing damage and deterioration of the first plate-like body 1. In addition, the order of the intermediate layer smoothing step and the intermediate layer firing step can be reversed.
The intermediate layer smoothing step can also be carried out by lapping, leveling, cutting and polishing the surface, or the like.

(Electrolyte layer formation step)
In the electrolyte layer forming step, the electrolyte layer 32 is formed in a thin layer state on the intermediate layer 34 while covering the electrode layer 31 and the intermediate layer 34. Alternatively, the electrolyte layer 32 may be formed in a thin film state having a thickness of 10 μm or less. As described above, the electrolyte layer 32 can be formed by a low-temperature firing method (a wet method in which firing is performed in a low-temperature range of 1100° C. or less), a spray coating method (a thermal spray method, an aerosol deposition method, an aerosol gas deposition method, a powder jet deposition method, a particle jet deposition method, a cold spray method, or the like), a PVD method (a sputtering method, a pulsed laser deposition method, or the like), a CVD method, or the like. In any case, it is preferable to perform the formation at a temperature of 1100° C. or less in order to suppress deterioration of the first plate-like body 1.

To form a high-quality electrolyte layer 32 that is dense, airtight, and has high gas barrier performance at a temperature range of 1100°C or less, it is desirable to perform the electrolyte layer formation step by a spray coating method. In this case, the material for the electrolyte layer 32 is sprayed toward the intermediate layer 34 on the first plate-like body 1 to form the electrolyte layer 32.

(Reaction prevention layer forming step)
In the reaction prevention layer forming step, the reaction prevention layer 35 is formed in a thin layer state on the electrolyte layer 32. As described above, the reaction prevention layer 35 can be formed by a low-temperature firing method (a wet method in which firing is performed in a low temperature range of 1100°C or less), a spray coating method (a thermal spray method, an aerosol deposition method, an aerosol gas deposition method, a powder jet deposition method, a particle jet deposition method, a cold spray method, etc.), a PVD method (a sputtering method, a pulse laser deposition method, etc.), a CVD method, etc. In any case, in order to suppress deterioration of the first plate-like body 1, it is desirable to perform the method at a temperature of 1100°C or less. In order to flatten the upper surface of the reaction prevention layer 35, for example, a leveling process or a cutting/polishing process may be performed on the surface after the formation of the reaction prevention layer 35, or a press process may be performed after the wet formation and before firing.

(Counter electrode layer forming step)
In the counter electrode layer forming step, the counter electrode layer 33 is formed in a thin layer state on the reaction prevention layer 35. As described above, the counter electrode layer 33 can be formed by a low-temperature firing method (a wet method in which firing is performed in a low temperature range of 1100°C or less), a spray coating method (a thermal spray method, an aerosol deposition method, an aerosol gas deposition method, a powder jet deposition method, a particle jet deposition method, a cold spray method, or the like), a PVD method (a sputtering method, a pulsed laser deposition method, or the like), a CVD method, or the like. In any case, it is preferable to perform the formation at a temperature of 1100°C or less in order to suppress deterioration of the first plate-like body 1.

In this manner, the electrochemical reaction section 3 can be manufactured.

In the electrochemical reaction section 3, it is possible to have a configuration in which either or both of the intermediate layer 34 and the reaction prevention layer 35 are not provided. That is, it is also possible to have a configuration in which the electrode layer 31 and the electrolyte layer 32 are in contact with each other, or a configuration in which the electrolyte layer 32 and the counter electrode layer 33 are in contact with each other. In this case, the above-mentioned manufacturing method omits the intermediate layer formation step and the reaction prevention layer formation step. It is also possible to add a step of forming another layer, or to stack multiple layers of the same type, but in either case, it is preferable to perform the process at a temperature of 1100°C or less.

(Electrochemical element stack)
As shown in Fig. 11, the electrochemical element stack S (electrochemical element assembly) has a plurality of electrochemical elements A, and with respect to adjacent electrochemical elements A, the plate-like support 10 constituting one electrochemical element A faces the plate-like support 10 constituting another electrochemical element A, and the outer surface of the second plate-like body 2 other than the first plate-like body 1 on which the electrochemical reaction section 3 in the plate-like support 10 constituting one electrochemical element A is electrically connected to the outer surface of the first plate-like body 1 in the plate-like support 10 constituting the other electrochemical element A, and a flow section A2 through which the second gas flows along the two outer surfaces is formed between the adjacent outer surfaces, and the electrochemical elements A are stacked (assembled). In order to electrically connect the electrochemical elements A, in addition to simply contacting the electrically conductive surface portions with each other, a method of applying a surface pressure to the contact surface or interposing a highly electrically conductive material to reduce contact resistance can be adopted. Specifically, each rectangular electrochemical element is aligned with the first through portion 41 at one end and the second through portion 51 at the other end, with the electrochemical reaction portion 3 of each electrochemical element A facing upward, and the first annular sealing portion 42 and the second annular sealing portion 52 are interposed between each first through portion 41 and second through portion 51, and the elements are stacked (assembled) to form the above-mentioned configuration.

The plate-shaped support 10 is provided with a first through-portion 41 on one end of the longitudinal direction of the rectangular plate-shaped support 10, which forms a supply path 4 for flowing a first gas, which is one of a reducing component gas and an oxidizing component gas, from the outer side in the surface penetration direction to the internal flow path A1. In the flow part A2, the plate-shaped support 10 is provided with a first annular seal portion 42 as an annular seal portion that separates the first through-portion 41 formed on both outer surfaces of the plate-shaped support 10 from the flow part A2, and the first through-portion 41 and the first annular seal portion 42 form the supply path 4 for flowing the first gas to the internal flow path A1. In addition, a ring-shaped bulge portion a is provided on the side of the first plate-shaped body 1 opposite to the internal flow path A1 around the portion where the first annular seal portion 42 contacts the first plate-shaped body 1, making it easy to position the first annular seal portion 42 in the direction along the surface of the first plate-shaped body 1.

The plate-shaped support 10 also has a second through-hole 51 at the other end that forms an exhaust passage 5 through which the first gas that has passed through the internal flow path A1 flows outward in the direction through the surface of the plate-shaped support 10. The second through-hole 51 is configured to allow the first gas to flow while being partitioned from the second gas. In the flow-through portion A2, the plate-shaped support 10 is provided with a second annular seal portion 52 that serves as an annular seal portion that partitions the second through-holes 51 formed on both outer surfaces of the plate-shaped support 10 from the flow-through portion A2. The second through-hole 51 and the second annular seal portion 52 form an exhaust passage 5 through which the first gas that has passed through the internal flow path A1 flows.

The first and second annular seal portions 42, 52 are made of insulating ceramic materials such as alumina, metals coated with such materials, or materials such as mica fibers and glass, and function as insulating seal portions that electrically insulate adjacent electrochemical elements from each other.

(Electrochemical module)
As shown in FIG. 11 , the electrochemical module M includes a housing B made of an insulator that houses the electrochemical element stack S, a first gas supply unit 61 that circulates a first gas from the outside of the housing B to the internal flow path A1 via a supply path 4, a first gas exhaust unit 62 that circulates the first gas after the reaction, a second gas supply unit 71 that circulates a second gas from the outside of the housing B to the flow unit A2, a second gas exhaust unit 72 that circulates the second gas after the reaction, and an output unit 8 that obtains an output associated with the electrochemical reaction in the electrochemical reaction unit 3. The electrochemical module M includes a distribution chamber 9 within the housing B that distributes and circulates the second gas circulated from the second gas supply unit 71 to the flow unit A2.
The distribution chamber 9 is a space located on the side (lateral side) of the electrochemical element stack S that serves as the inlet or outlet of the flow section of the electrochemical element stack S, and the flow section A2 is formed with an opening on the space side and is connected to the space.

The electrochemical element stack S is housed in the housing B in a state where it is sandwiched between a pair of current collectors 81, 82, and an output section 8 is extended from the current collectors 81, 82 so that it can be freely connected to a power supply destination outside the housing B. The current collectors 81, 82 accommodate the electrochemical element stack S in an airtight manner in the housing B, and the current collectors 81, 82 are arranged to function as buffer materials for each electrochemical element A.

As a result, the electrochemical module M flows fuel gas from the first gas supply unit 61 and air from the second gas supply unit 71, so that the fuel gas enters as shown by the dashed arrows in Fig. 11 and air enters as shown by the solid arrows in Fig. 11. The fuel gas flowing from the first gas supply unit 61 is guided to the supply path 4 from the first penetration portion 41 of the uppermost electrochemical element A of the electrochemical element stack S, and flows through the internal flow paths A1 of all the electrochemical elements A from the supply path 4 partitioned by the first annular seal portion 42. The air flowing from the second gas supply unit 71 temporarily flows into the distribution chamber 9, and then flows through the flow portions A2 formed between the electrochemical elements A.
Incidentally, when the second plate-like body 2 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 a portion where the corrugated second plate-like body 2 bulges out from the first plate-like body 1, and the corrugated second plate-like body 2 comes into contact with the electrochemical reaction section 3 of the adjacent electrochemical element A to enable 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.
In a portion of FIG. 10, the electrochemical element A in which a cross section including the internal flow path A1 appears and the electrochemical element A in which a cross section including the flow section A2 appears are shown side by side for convenience, but the fuel gas flowing from the first gas supply section 61 reaches the distribution section A12 (see FIGS. 1, 4, and 7), spreads along the width direction of the one end side through the distribution section A12, and reaches each sub-flow path A11 of the internal flow path A1 (see FIGS. 1, 3, and 7). Then, the fuel gas that has entered the internal flow path A1 can enter the electrode layer 31 through the gas flow allowance section 1A. In addition, the fuel gas further advances through the internal flow path A1 together with the fuel gas that has undergone electrochemical reaction, and advances through the junction section A13 and the second through-hole section 51 to the discharge path 5 formed by the second annular seal section 52, and is circulated outside the housing B from the first gas discharge section 62 together with the fuel gas that has undergone electrochemical reaction from the other electrochemical elements A. On the other hand, the air circulated from the second gas supply unit 71 enters the flow section A2 via the distribution chamber 9, and can enter the counter electrode layer 33. The air, together with the air that has undergone the electrochemical reaction, further travels through the flow section A2 along the electrochemical reaction unit 3, and is circulated outside the housing B through the second gas exhaust unit 72.

The electricity generated in the electrochemical reaction section 3 by the flow of the fuel gas and air is connected in series between the current collectors 81, 82 by 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 electrochemical module M described above can be used to construct an electrochemical device 100 and an energy system Z.

In addition, the electrochemical elements A do not have to be stacked in the electrochemical module M. In other words, the electrochemical elements A may be arranged in a group in the electrochemical module M.

(Annular spacer)
3, 8, 9, and 11, in each of the electrochemical elements A, an annular spacer 91 is disposed between the first plate-like body 1 and the second plate-like body 2. The annular spacer 91 is disposed on one end side (first penetrating portion 41) and the other end side (second penetrating portion 51) of the plate-like support 10.

(First Example of Annular Spacer)
A first example of the annular spacer 91 will be described with reference to Figures 15, 16, and 17. In the cross-sectional view of Figure 17, the cross section of the annular spacer 91 is drawn as a cross section taken along plane CS1 shown in Figure 16.

The annular spacer 91 is a plate-like member with a through hole 91a extending from the front to the back. The annular spacer 91 has a flow path 91b that allows gas to flow from the space SI inside the through hole 91a to the space SO outside the annular spacer 91 when sandwiched between other members (the first plate-like body 1 and the second plate-like body 2).

Specifically, the annular spacer 91 is a disk-shaped member having a through hole 91a in the center. The annular spacer 91 can be integrally formed by pressing. The annular spacer 91 may be formed of an electrically conductive material. For example, the annular spacer 91 is made of a metal. It is preferable that the material of the annular spacer 91 includes one or more of ferritic stainless steel, austenitic stainless steel, Inconel, copper, and Invar material. The material of the annular spacer 91 may be an insulator.

The first example of the annular spacer 91 includes a base portion 92, a protruding portion 93, and a flange portion 94.

The base 92 is a portion that extends like a flat plate.

The protrusions 93 are parts of the base 92 that protrude in the front-back direction (the up-down direction in FIG. 17, the up-down direction in the electrochemical element) beyond the periphery. In the illustrated example, the annular spacer 91 has eight protrusions 93 arranged evenly in the circumferential direction. The upper surfaces of the protrusions 93 are flat. The upper surfaces of all of the protrusions 93 are approximately the same height. The annular spacer 91 may have protrusions on both the front and back surfaces. The number of protrusions 93 is not limited to 8, and may be 1 to 7, or 9 or more.

The flange portion 94 is a flange-shaped portion that protrudes in the front-back direction from the center of the base portion 92. The flange portion 94 is the peripheral wall of the through hole 91a. In the illustrated example, the flange portion 94 protrudes on the opposite side to the protruding portion 93 in the front-back direction. The flange portion 94 is formed in an annular shape. The flange portion 94 is a continuous annular shape. A portion of the flange portion 94 may be cut out. In other words, the flange portion 94 may be a discontinuous annular shape.

Figure 17 shows the state in which the annular spacer 91 of the first example is arranged between the first plate-like body 1 and the second plate-like body 2. The flange portion 94 fits into the second through-hole 51 (through-hole 2b) of the second plate-like body 2. The flange portion 94 positions the annular spacer 91 with respect to the second plate-like body 2. The upper surface of the annular spacer 91, i.e., the upper surface of the protruding portion 93, contacts the lower surface of the first plate-like body 1. The lower surface of the base portion 92 contacts the upper surface of the second plate-like body 2. The first plate-like body 1 and the second plate-like body 2 can be electrically connected through the annular spacer 91. Compared to the case in which the annular spacer 91 is not present, the electrical conductivity between the first plate-like body 1 and the second plate-like body 2 is improved.

The presence of the protrusions 93 creates a space P between the base 92 and the first plate-like body 1. The space P is the space around the protrusions 93. The space P connects the internal flow path A1 of the plate-like support 10 (the space SO outside the annular spacer 91) and the space SI inside the through hole 91a of the annular spacer 91. The space P is formed between the two protrusions 93. Since the annular spacer 91 has eight protrusions 93, the eight spaces P are positioned in a circumferential line around the through hole 91a.

17, the annular spacer 91 is arranged with its central axis (the central axis of the through hole 91a) coinciding with the central axis of the second through portion 51. In detail, the annular spacer 91 is arranged with its central axis (the central axis of the through hole 91a) coinciding with the central axis of the through hole 1b formed in the first plate-like body 1, the central axis of the through hole 2b formed in the second plate-like body 2, and the central axis of the second annular seal portion 52. Therefore, the annular spacer 91 is arranged so that the second through portion 51 (through hole 2b) and the through hole 91a of the annular spacer 91 overlap when viewed in the thickness direction of the plate-like support body 10. In this embodiment, the annular spacer 91 is arranged so that the second through portion 51 (through hole 2b) and the entire through hole 91a overlap. The annular spacer 91 may be arranged so that the second through portion 51 (through hole 2b) and a part of the through hole 91a overlap.

Figure 17 shows the state in which the annular spacer 91 is arranged on the other end side (second penetration portion 51) of the plate-shaped support 10. The annular spacer 91 arranged on one end side (first penetration portion 41) of the plate-shaped support 10 also has the same shape as the example shown in Figure 17.

When fuel gas (first gas, an example of a "gas") is supplied to the first penetration 41, the fuel gas flows from the penetration hole 91a of the annular spacer 91 through the space P into the internal flow path A1. The fuel gas that has flowed through the internal flow path A1 then flows into the penetration hole 91a through the space P of the annular spacer 91 on the second penetration 51 side, and flows out to the second penetration 51. In this way, the space P functions as the flow path 91b.

The annular spacer 91 has eight flow paths 91b corresponding to the eight spaces P. The eight flow paths 91b extend radially from the through hole 91a. The eight flow paths 91b are arranged in a line in the circumferential direction. Therefore, the first gas from the first through portion 41 can be effectively diffused to the internal flow path A1 (distribution portion A12). In other words, the annular spacer 91 can uniformly supply the first gas to the multiple sub-flow paths A11.

(Second Example of Annular Spacer)
18, 19, and 20, a second example of the annular spacer 91 will be described. In the cross-sectional view of Fig. 20, the cross section of the annular spacer 91 is drawn as a cross section along the plane CS2 shown in Fig. 19.

The annular spacer 91 of the second example is a plate-like member with through holes 91a from the front to the back, as in the first example. The annular spacer 91 has a flow path 91b that allows gas to flow from the space SI inside the through holes 91a to the space SO outside the annular spacer 91 when sandwiched between other members (the first plate-like body 1 and the second plate-like body 2).

Specifically, the annular spacer 91 is a disk-shaped member having a through hole 91a in the center. The annular spacer 91 can be integrally formed by pressing. The annular spacer 91 may be formed of an electrically conductive material. For example, the annular spacer 91 is made of a metal. It is preferable that the material of the annular spacer 91 includes one or more of ferritic stainless steel, austenitic stainless steel, Inconel, copper, and Invar material. The material of the annular spacer 91 may be an insulator.

The second example of the annular spacer 91 has a first portion 95 and a second portion 96.

The first portions 95 are portions that extend in a flat plate shape. In the illustrated example, the annular spacer 91 has eight first portions 95 that are arranged with a gap T in the circumferential direction. The upper and lower surfaces of the first portions 95 are flat. The upper and lower surfaces of all the first portions 95 are approximately the same height. In other words, all the first portions 95 are arranged on the same plane. The height of the upper surface, the height of the lower surface, and the thickness of the first portions 95 may differ from one another among the first portions 95. The number of first portions 95 is not limited to eight, and may be two to seven, or may be nine or more.

The gaps T extend from the outer peripheral end of the annular spacer 91 to the through hole 91a. Since the annular spacer 91 has eight first portions 95, eight gaps T are positioned in a circumferential line around the through hole 91a. In the illustrated example, the width of the eight gaps T is the same. The widths of the gaps T may be different.

The second portion 96 is a portion that connects multiple first portions 95. The second portion 96 is a flange-shaped portion that protrudes in the front-rear direction at the center of the annular spacer 91. The second portion 96 is the peripheral wall of the through hole 91a. The second portion 96 is connected to the lower surface of the first portion 95 and protrudes downward from the first portion 95. In the illustrated example, the second portion 96 is formed in an annular shape. A portion of the second portion 96 may be cut out. In other words, the second portion 96 may be a discontinuous annular shape.

Figure 20 shows the state in which the annular spacer 91 of the second example is disposed between the first plate-like body 1 and the second plate-like body 2. The second portion 96 is inserted into the second through-hole 51 (through-hole 2b) of the second plate-like body 2. The second portion 96 positions the annular spacer 91 relative to the second plate-like body 2. The upper surface of the annular spacer 91, i.e., the upper surface of the first portion 95, contacts the lower surface of the first plate-like body 1. The lower surface of the first portion 95 contacts the upper surface of the second plate-like body 2. The first plate-like body 1 and the second plate-like body 2 can be electrically conductive through the annular spacer 91. Compared to the case in which the annular spacer 91 is not present, the electrical conductivity between the first plate-like body 1 and the second plate-like body 2 is improved.

In the state shown in FIG. 20, the gap T is surrounded by the two first portions 95, the first plate-like body 1, and the second plate-like body 2. The gap T connects the internal flow path A1 of the plate-like support body 10 (the space SO outside the annular spacer 91) to the space SI inside the through hole 91a of the annular spacer 91.

As shown in FIG. 20, and similarly to the first example, the annular spacer 91 is arranged with its central axis (the central axis of the through hole 91a) coinciding with the central axis of the second through portion 51. In detail, the annular spacer 91 is arranged with its central axis (the central axis of the through hole 91a) coinciding with the central axis of the through hole 1b formed in the first plate-like body 1, the central axis of the through hole 2b formed in the second plate-like body 2, and the central axis of the second annular seal portion 52. Therefore, the annular spacer 91 is arranged so that the second through portion 51 (through hole 2b) and the through hole 91a of the annular spacer 91 overlap when viewed in the thickness direction of the plate-like support body 10. In this embodiment, the annular spacer 91 is arranged so that the second through portion 51 (through hole 2b) and the entire through hole 91a overlap. The annular spacer 91 may be arranged so that the second through portion 51 (through hole 2b) and a part of the through hole 91a overlap.

Figure 20 shows the state in which the annular spacer 91 is arranged on the other end side (second penetration portion 51) of the plate-shaped support 10. The annular spacer 91 arranged on one end side (first penetration portion 41) of the plate-shaped support 10 also has the same shape as the example shown in Figure 20.

When fuel gas (first gas, an example of a "gas") is supplied to the first penetration 41, the fuel gas flows from the penetration hole 91a of the annular spacer 91 through the gap T into the internal flow path A1. The fuel gas that has flowed through the internal flow path A1 then flows into the penetration hole 91a through the gap T of the annular spacer 91 on the second penetration 51 side, and flows out to the second penetration 51. In this way, the gap T functions as the flow path 91b.

The annular spacer 91 has eight flow paths 91b corresponding to the eight gaps T. The eight flow paths 91b extend radially from the through hole 91a. The eight flow paths 91b are arranged in a line in the circumferential direction. Therefore, the first gas from the first through portion 41 can be effectively diffused to the internal flow path A1 (distribution portion A12). In other words, the annular spacer 91 can uniformly supply the first gas to the multiple sub-flow paths A11.

The advantages of the annular spacer 91 common to the first and second examples will be described. In the electrochemical module M, a plurality of electrochemical elements A are stacked. The plurality of electrochemical elements A are pressed in the stacking direction. Then, a force acts from the first annular seal portion 42 and the second annular seal portion 52 to the plate-like support 10. That is, a compressive force acts on the plate-like support 10 in the thickness direction. The presence of the annular spacer 91 suppresses deformation of the plate-like support 10 (particularly deformation in the thickness direction). In addition, the reaction force from the plate-like support 10 to the first annular seal portion 42 and the second annular seal portion 52 becomes large. The first annular seal portion 42 and the second annular seal portion 52 are strongly pressed against the plate-like support 10. The airtightness is improved at the contact portion between the first annular seal portion 42 and the plate-like support 10 and at the contact portion between the second annular seal portion 52 and the plate-like support 10.

The annular spacer 91 may be arranged upside down compared to the examples shown in Figures 17 and 20. In other words, the annular spacer 91 may be arranged upside down compared to the examples shown in Figures 17 and 20.

The annular spacer 91 in the first and second examples is a circular ring. The annular spacer 91 may be an annular spacer of any shape, such as an elliptical, rectangular, or polygonal shape.

(Energy systems, electrochemical devices)
FIG. 12 shows an overview of an energy system Z and an electrochemical device 100.
The energy system Z includes an electrochemical device 100 and a heat exchanger 200 serving as an exhaust heat utilization section that reuses heat circulated from the electrochemical device 100 .
The electrochemical device 100 has an electrochemical module M, a desulfurizer 101, and a reformer 102, which is a type of fuel converter, as well as a fuel supply unit 103 that circulates fuel gas containing a reducing component to the electrochemical module M, and an inverter 104, which is a type of power converter, as an output unit 8 that extracts electric power from the electrochemical module M.

In detail, the electrochemical device 100 has a desulfurizer 101, a reforming water tank 105, a vaporizer 106, a reformer 102, a blower 107, a combustion section 108, an inverter 104, a control section 110, and an electrochemical module M.

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 the adverse effects of the sulfur compounds on the reformer 102 or the electrochemical element A. The vaporizer 106 generates steam from the reforming water flowing from the reforming water tank 105. The reformer 102 uses the steam generated by the vaporizer 106 to steam reform the raw fuel desulfurized by the desulfurizer 101, generating a reformed gas containing hydrogen.

The electrochemical module M generates electricity by electrochemically reacting the reformed gas circulated from the reformer 102 with the air circulated from the blower 107. The combustion section 108 mixes the reaction exhaust gas circulated from the electrochemical module M with air and combusts the combustible components in the reaction exhaust gas.

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

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.

The raw fuel is circulated to the desulfurizer 101 through the raw fuel supply passage 112 by the operation of the boost pump 111. The reforming water in the reforming water tank 105 is circulated to the vaporizer 106 through the reforming water supply passage 114 by the operation of the reforming water pump 113. The raw fuel supply passage 112 merges with the reforming water supply passage 114 at a location downstream of the desulfurizer 101, and the reforming water and raw fuel that are merged outside the housing B are circulated to the vaporizer 106.

The reforming water is vaporized in the vaporizer 106 to become water vapor. The raw fuel containing water vapor generated in the vaporizer 106 is circulated to the reformer 102 through the water vapor-containing raw fuel supply passage 115. The raw fuel is steam reformed in the reformer 102 to generate a reformed gas (a first gas having a reducing component) mainly composed of hydrogen gas. The reformed gas generated in the reformer 102 is circulated to the electrochemical module M through the fuel supply unit 103.

The reaction exhaust gas is combusted in the combustion section 108 to become combustion exhaust gas, which is sent to the heat exchanger 200 through the combustion exhaust gas exhaust passage 116. A combustion catalyst section 117 (e.g., a platinum-based catalyst) is arranged in the combustion exhaust gas exhaust passage 116, and reducing components such as carbon monoxide and hydrogen contained in the combustion exhaust gas are burned and removed.

The heat exchanger 200 exchanges heat between the exhaust gas generated by combustion in the combustion section 108 and the cold water being circulated, generating hot water. In other words, the heat exchanger 200 operates as a waste heat utilization section that reuses the heat discharged from the electrochemical device 100.

In place of the exhaust heat utilization section, a reaction exhaust gas utilization section may be provided that utilizes the reaction exhaust gas circulating (without being combusted) from the electrochemical module M. Also, at least a portion of the reaction exhaust gas circulating from the first gas exhaust section 62 to the outside of the housing B may be recycled by merging with any of the locations 100, 101, 103, 106, 112, 113, and 115 in FIG. 12. The reaction exhaust gas contains residual hydrogen gas that was not used in the reaction in the electrochemical element A. In the reaction exhaust gas utilization section, the residual hydrogen gas is utilized for heat utilization by combustion or for power generation by a fuel cell or the like, thereby making effective use of energy.

Fig. 14 shows an example of the energy system Z and the electrochemical device 100 in the case where the electrochemical reaction section 3 is operated as an electrolysis cell. In this system, supplied water and carbon dioxide are electrolyzed in the electrochemical reaction section 3 to generate hydrogen, carbon monoxide, etc. Furthermore, hydrocarbons and the like are synthesized in the fuel converter 25. By configuring the heat exchanger 24 in Fig. 14 to operate as an exhaust heat utilization section that exchanges heat between the reaction heat generated by the reaction in the fuel converter 25 and water to vaporize it, and by configuring the heat exchanger 23 in Fig. 14 to operate as an exhaust heat utilization section that exchanges heat between the exhaust heat generated by the electrochemical element A and water vapor and carbon dioxide to preheat it, it is possible to improve energy efficiency.
Furthermore, the power converter 104 (converter) supplies power to the electrochemical device A. This allows the electrochemical device A to function as an electrolysis cell as described above.
Therefore, according to the above configuration, it is possible to provide an electrochemical device 100 and an energy system Z that can improve the efficiency of converting electrical energy into chemical energy such as fuel.

Other Embodiments
(1) 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. In addition, 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.

(2) 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 ₂ , or Cu _- CeO ₂ , 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 passing hydrogen gas through the electrode layer 31 to make it a fuel electrode (anode) and passing air through the counter electrode layer 33 to make it an air electrode (cathode). It is also possible to change this configuration and configure the electrochemical element A so that the electrode layer 31 can be made an air electrode and the counter electrode layer 33 can be made a fuel electrode. That is, for example, a composite oxide such as LSCF or LSM is used as the material of the electrode layer 31, and for example, a composite material such as NiO _- GDC, Ni _- GDC, NiO _- YSZ, Ni _- YSZ, CuO _{- CeO2} , or Cu _{- CeO2} is used as the material of the counter electrode layer 33. In the electrochemical element A configured in this manner, air is circulated through the electrode layer 31 to serve as an air electrode, and hydrogen gas is circulated through the counter electrode layer 33 to serve as a fuel electrode, so that the electrochemical element A can be used as a solid oxide fuel cell.

(3) In the above embodiment, the electrode layer 31 is disposed between the first plate-like body 1 and the electrolyte layer 32, and the counter electrode layer 33 is disposed on the side opposite the first plate-like body 1 as viewed from the electrolyte layer 32. 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-like body 1 and the electrolyte layer 32, and the electrode layer 31 is disposed on the side opposite the first plate-like body 1 as viewed from the electrolyte layer 32 is also possible. In this case, it is also necessary to change the flow of gas to the electrochemical element A.
In other words, 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 arranged so as to flow in a form that allows them to react appropriately with the electrode layer 31 and the counter electrode layer 33.

(4) In the above embodiment, the electrochemical reaction section 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 section 1A, but it may be provided on the second plate-like body 2 side of the first plate-like body 1. In other words, the present invention is valid even if the electrochemical reaction section 3 is configured to be disposed in the internal flow path A1.

(5) In the above embodiment, the first through-hole 41 and the second through-hole 51 are provided in pairs at both ends of the rectangular plate-like support 10, but the present invention is not limited to providing them at both ends, and two or more pairs may be provided. In addition, the first through-hole 41 and the second through-hole 51 do not need to be provided in pairs. Thus, one or more first through-holes 41 and one or more second through-holes 51 may be provided.
Furthermore, the shape of the plate-like support 10 is not limited to a rectangular shape, but various shapes such as a square shape, a circular shape, etc. can be adopted.

(6) The first and second annular seal portions 42, 52 may have any shape as long as they are configured to connect the first and second through-holes 41, 51 to each other and prevent gas leakage. In other words, the first and second annular seal portions 42, 52 may have an endless configuration with an opening therein that connects to the through-hole, and may be configured to seal between adjacent electrochemical elements A. The first and second annular seal portions 42, 52 may be, for example, annular. The annular shape may be any shape, such as circular, elliptical, rectangular, or polygonal.

(7) In the above, the plate-shaped support 10 is composed of a first plate-shaped body 1 and a second plate-shaped body 2. Here, the first plate-shaped body 1 and the second plate-shaped body 2 may be composed of separate plate-shaped bodies, or may be composed of a single plate-shaped body as shown in FIG. 13. In the case of FIG. 13, for example, the first plate-shaped body 1 and the second plate-shaped body 2 are overlapped by folding the single plate-shaped body. Then, the first plate-shaped body 1 and the second plate-shaped body 2 are integrated by welding the peripheral portion 1a or the like. Note that the first plate-shaped body 1 and the second plate-shaped body 2 may be composed of a series of seamless plate-shaped bodies, or may be molded as shown in FIG. 13 by folding a series of plate-shaped bodies.
As described later, the second plate-like body 2 may be made of one member or may be made of two or more members. Similarly, the first plate-like body 1 may be made of one member or may be made of two or more members.

(8) The second plate-like body 2 forms an internal flow path A1 together with the first plate-like body 1. The internal flow path A1 has a distribution section A12, a plurality of sub-flow paths A11, and a junction section A13. The first gas supplied to the distribution section A12 is distributed and supplied to each of the plurality of sub-flow paths A11 as shown in Fig. 1, and is junctioned at the junction section A13 at the outlets of the plurality of sub-flow paths A11. Thus, the first gas flows along the gas flow direction from the distribution section A12 toward the junction section A13.
The sub-flow passages A11 are formed by forming the second plate-like body 2 in a corrugated shape from the distribution section A12 to the junction section A13. As shown in FIG. 5, the sub-flow passages A11 are formed in a corrugated shape in a cross-sectional view in a flow cross direction that crosses the gas flow direction of the first gas. Such a sub-flow passages A11 are formed by extending a corrugated plate along the gas flow direction shown in FIG. 1. The sub-flow passages A11 may be formed from a series of corrugated plate-like bodies between the distribution section A12 and the junction section A13, or may be composed of two or more corrugated plate-like bodies. The sub-flow passages A11 may be formed from, for example, two or more corrugated plate-like bodies separated along the gas flow direction, or may be composed of two or more corrugated plate-like bodies separated along the flow cross direction.

The multiple sub-flow paths A11 are formed in a wavy shape by repeatedly forming peaks and valleys of the same shape as shown in FIG. 5. However, the second plate-like body 2 may have plate-like portions in the area where the multiple sub-flow paths A11 are formed. For example, the multiple 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.

(9) The portion of the second plate-like body 2 corresponding to the multiple sub-flow paths A11 does not need to be entirely corrugated, but at least a portion of it may be corrugated. For example, between the distribution section A12 and the merging section A13, the second plate-like body 2 may have a flat portion in the gas flow direction and a corrugated portion in the remainder. Also, the second plate-like body 2 may have a flat portion in the cross-flow direction and a corrugated portion in the remainder.

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

The configurations disclosed in the above embodiments can be applied in combination with configurations disclosed in other embodiments, provided no inconsistencies arise. Furthermore, the embodiments disclosed in this specification are merely examples, and the present invention is not limited to these embodiments. They can be modified as appropriate within the scope of the purpose of the present invention.

The present invention can be used in annular spacers, electrochemical elements, electrochemical modules, electrochemical devices, energy systems, solid oxide fuel cells and solid oxide electrolysis cells.

1: First plate-like body 2: Second plate-like body 10: Plate-like support body 25: Fuel converter 31: Electrode layer (first electrode, second electrode)
32: Electrolyte layer 33: Counter electrode layer (first electrode, second electrode)
41: First penetration part (penetration part)
51: Second penetration part (penetration part)
91: Annular spacer 91a: Through hole 91b: Flow path 93: Protrusion 95: First portion 96: Second portion 100: Electrochemical device 104: Power converter 200: Heat exchanger (exhaust heat utilization portion)
A: Electrochemical element A1: Internal flow path CS1: Surface CS2: Surface M: Electrochemical module P: Space SI: Space SO: Space T: Gap Z: Energy system

Claims (13)

a plate-shaped annular spacer having a through hole extending from the front to the back, the plate-shaped annular spacer including a flow path for allowing a gas to flow from a space inside the through hole to a space outside the annular spacer when the plate-shaped annular spacer is sandwiched between other members ;
The annular spacer includes a flange portion on at least one of a front surface and a back surface, the flange portion protruding in a front-back direction from a periphery at a central portion of the annular spacer so as to form a peripheral wall of the through hole . 2. An annular spacer as described in claim 1, comprising a flat base and a protrusion on at least one of the front and back surfaces of the base that protrudes in the front-back direction beyond the surrounding area, the space around the protrusion functions as the flow path , and the flange portion is provided in the center of the base . 2. The annular spacer according to claim 1, comprising a plurality of first portions arranged with gaps therebetween and a second portion connecting the first portions, the gaps functioning as the flow paths and the second portions functioning as the flange portions . The annular spacer according to any one of claims 1 to 3, which is made of an electrically conductive material. The annular spacer according to claim 4, wherein the material includes one or more of ferritic stainless steel, austenitic stainless steel, Inconel, copper, and Invar. An electrochemical element comprising: an electrolyte layer; a first electrode and a second electrode disposed on either side of the electrolyte layer; and a plate-shaped support supporting the electrolyte layer, the first electrode, and the second electrode,
The plate-shaped support includes a conductive first plate-shaped body, a conductive second plate-shaped body, and an internal flow path formed between opposing surfaces of the first plate-shaped body and the second plate-shaped body,
An electrochemical element, comprising: the annular spacer according to claim 1 disposed between the first plate-like body and the second plate-like body. The electrochemical element according to claim 6, wherein at least one of the first plate-like body and the second plate-like body has a through-hole that forms a gas supply path to the internal flow path, and the annular spacer is arranged so that the through-hole overlaps with the through-hole of the annular spacer when viewed in the thickness direction of the plate-like support. An electrochemical module in which a plurality of electrochemical elements according to claim 6 or 7 are arranged in an assembled state. An electrochemical device comprising at least the electrochemical element according to claim 6 or 7 or the electrochemical module according to claim 8, and a fuel converter that generates a reducing component to be supplied to the electrochemical element or the electrochemical module, or that converts a gas containing a reducing component generated by the electrochemical element or the electrochemical module. An electrochemical device comprising at least the electrochemical element according to claim 6 or 7 or the electrochemical module according to claim 8, and a power converter that extracts power from the electrochemical element or the electrochemical module or passes power to the electrochemical element or the electrochemical module. An energy system having the electrochemical device according to claim 9 or 10 and a waste heat utilization section that reuses heat discharged from the electrochemical device. A solid oxide fuel cell comprising the electrochemical element according to claim 6 or 7, in which a power generation reaction occurs in the electrochemical element. A solid oxide electrolysis cell comprising the electrochemical element according to claim 6 or 7, in which an electrolytic reaction occurs.

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