JP7650699B2 - Electrochemical modules, electrochemical devices, energy systems, solid oxide fuel cells and solid oxide electrolysis cells - Google Patents

Description

The present invention relates to electrochemical modules, electrochemical devices, energy systems, solid oxide fuel cells, and solid oxide electrolysis cells.

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 or 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.

Electrochemical modules such as those found in fuel cells (electrochemical power generation cells) and electrolysis cells need to be able to position flat electrochemical elements when they are fitted inside a housing, and to prevent misalignment of the flat electrochemical elements caused by thermal expansion due to heat generated when the electrochemical module is in use.

Patent documents 2 to 7 disclose the following configurations that can prevent such positioning and misalignment.

For example, Patent Document 2 discloses a configuration in which a positioning pin is used to prevent the fuel cell from being misaligned relative to the fuel cell stack. Patent Document 3 discloses a configuration in which a pin is used to position the first stack. Patent Document 4 discloses a configuration in which a unit cell is positioned using a positioning pin.

Patent Document 5 discloses a configuration in which a positioning section formed by a recess on the back surface of an embossed section provided in a reaction gas buffer section positions multiple power generation cells. Patent Document 6 discloses a configuration in which a separator is provided with a connecting section that connects the end of a first flat section to the end of a second flat section, and the connecting section functions like a spring that easily expands and contracts in the surface direction, thereby suppressing positional deviation of multiple unit cells. Patent Document 7 discloses a configuration in which the outer periphery of multiple electrochemical elements is positioned via an insulating material and the elements are stacked and mounted inside a housing.

Special table 2017-508254 publication JP 2019-192503 A JP 2012-3893 A JP 2020-126748 A JP 2017-168289 A JP 2019-169240 A JP 2020-167128 A

However, the configuration described in Patent Document 2 requires the design of positioning pins to accommodate dimensional tolerances during manufacturing of fuel cell units and thermal expansion of each part during use of the fuel cell, and machining is also required to fix the positioning pins, resulting in high costs.

In addition, when the fuel cell is in use, a temperature difference can occur in the stacking direction of the fuel cell, causing a difference in the amount of expansion of the fuel cell. This causes a difference in the force with which the positioning pins suppress the misalignment of the fuel cell, and if stress is concentrated in the fuel cell, the fuel cell may be deformed or the positioning pin may be damaged.

Furthermore, since the positioning pins come into contact with the fuel cell, they must be made of a material that is electrically insulating and highly rigid, such as an expensive material such as alumina. If the positioning pins do not have electrical insulation, a separate electrically insulating material must be provided. This poses the problem of high costs. The same problem may arise with the configurations described in Patent Documents 3 and 4.

The configuration described in Patent Document 5 has the risk of the power generation cells being deformed or damaged because the dimensional tolerances during manufacturing of the power generation cells and the thermal expansion of each part during use of the fuel cell are restrained by the fitting of the positioning parts. In addition, there is a problem in that costs are high because a material with electrical insulation and high rigidity, such as an expensive material such as alumina, must be disposed between adjacent power generation cells.

The configuration described in Patent Document 6 has the problem that the unit cell and the separator are joined by joints formed with a brazing material, which requires labor and material costs to create, resulting in high costs. In addition, because the configuration connects the convex and concave parts of adjacent connecting parts, stress caused by thermal expansion of each part during use of the fuel cell system is concentrated on the convex parts, which may cause fatigue damage to the convex parts, creating problems from the perspective of long-term durability.

In the configuration described in Patent Document 7, when the elastic force of the insulating material is small (Young's modulus is large) or when the insulating member is thin, the thermal expansion of each part during use of the fuel cell cannot be fully absorbed, and the restraining force of the insulating material on the electrochemical element becomes strong, which may cause deformation or damage to the electrochemical element.

Therefore, in view of the above circumstances, the present invention aims to provide an electrochemical module that is inexpensive, allows easy positioning of electrochemical elements, and suppresses positional deviation. It is also an object of the present invention to provide electrochemical devices, energy systems, solid oxide fuel cells, and solid oxide electrolysis cells at low cost.

As a means for achieving the above-mentioned object, the electrochemical module has a characteristic configuration comprising a flat electrochemical element in which an electrolyte layer and a first electrode and a second electrode respectively arranged on either side of the electrolyte layer are formed along a substrate, a housing surrounding the periphery of the electrochemical element, and a buffer section arranged between at least a portion of the periphery of the electrochemical element and the housing, the housing and the electrochemical element having approximately the same thermal expansion coefficient, and the substrate being a plate-shaped support body made of metal .

The material constituting the buffer section is preferably a material having excellent electrical insulation, heat resistance, and compression resistance, and an example of such a material is soft mica (phlogopite). Soft mica is a material with greater flexibility than hard mica (muscovite). By having a buffer section made of a material with a certain degree of flexibility, such as soft mica, it is easy to position the electrochemical element when it is housed in the housing.
In addition, by providing a buffer section made of a material having a certain degree of flexibility, such as soft mica, the buffer section absorbs external forces acting on the housing, thereby suppressing acceleration and impact forces acting on the electrochemical element and preventing it from being displaced.
The housing and the electrochemical element each undergo thermal expansion due to heat generation during use of the electrochemical module. If the electrochemical element were directly mounted inside the housing without disposing a buffer section, there would be a risk of defects such as deformation or damage to the electrochemical element. In contrast, since the buffer section is disposed between at least a part of the periphery of the electrochemical element and the housing as described above, the thermal expansion of the electrochemical element and the housing can be absorbed, thereby suppressing the risk of defects such as deformation or damage to the electrochemical element.
When the buffer portion is disposed so as to contact the entire circumference of the electrochemical element, the buffer portion can improve the airtightness of the space in which the electrochemical element is housed. Since the gas required for the electrochemical element does not leak, the amount of the gas required to be supplied can be reduced.
In addition, the housing and the electrochemical element each undergo thermal expansion due to heat generation during use of the electrochemical module. Since the electrochemical element is housed within the housing, if the thermal expansion coefficients of the housing and the electrochemical element differ significantly, there is a risk of defects such as deformation and damage occurring in the electrochemical element. In contrast, as described above, the housing and the electrochemical element have approximately the same thermal expansion coefficients, and therefore thermally expand to the same extent. Therefore, the difference in thermal expansion between the electrochemical element and the housing is kept small, and the risk of defects such as deformation and damage occurring in the electrochemical element can be suppressed.
Furthermore, in the case where a plurality of electrochemical elements are stacked, a temperature difference may occur between the plurality of electrochemical elements during use of the electrochemical module, which may cause a difference in the amount of expansion of each electrochemical element. Even in such a case, since the buffer section is disposed between the periphery of the plurality of electrochemical elements and the housing, the expansion of each of the plurality of electrochemical elements can be absorbed by the buffer section, and the risk of defects such as deformation or damage occurring to each electrochemical element can be reduced.
Furthermore, if the substrate is a metal plate-like support, the electrochemical module is one in which the components of a flat-plate electrochemical element, such as an electrode layer, an electrolyte layer, and a counter electrode layer, are formed on a metal plate-like support having excellent strength, and it is therefore possible to make the components of the flat-plate electrochemical element, such as the electrode layer, electrolyte layer, and counter electrode layer, thinner, thereby making it possible to reduce the material cost of the electrochemical module.

In the present invention, it is preferable that the Young's modulus of the flexible material constituting the buffer section is 10 MPa or more and 35 MPa or less.

As a result of intensive research by the inventors, it was found that if the buffer section has a Young's modulus of 10 MPa or more and 35 MPa or less, the electrochemical element can be positioned easily and misalignment is more suppressed. The buffer section preferably has a Young's modulus of 15 MPa or more, and more preferably has a Young's modulus of 18 MPa or more. The buffer section preferably has a Young's modulus of 30 MPa or less, and more preferably has a Young's modulus of 20 MPa or less. If the buffer section has a Young's modulus of less than 10 MPa, it is difficult to suppress misalignment, and if it is greater than 30 MPa, it is difficult to achieve a buffering effect.

In the present invention, it is preferable that the flexible member constituting the buffer portion is formed in a plate shape, and the thickness of the flexible member is 0.1% to 10% of the length of the electrochemical element in the planar direction.

As a result of intensive research by the inventors, it was found that when the thickness of the buffer portion is 0.1% or more and 10% or less of the in-plane length of the electrochemical element, the electrochemical element can be easily positioned and misalignment can be more effectively prevented. The thickness of the buffer portion is preferably 0.3% or more, and more preferably 0.5% or more. The thickness of the buffer portion is preferably 5% or less, and more preferably 2% or less. If the thickness of the buffer portion is less than 0.1%, it is too thin and does not provide a sufficient buffering effect, and if it is more than 10%, it is difficult to position the electrochemical element and does not provide a sufficient effect of preventing misalignment.

In the present invention, it is preferable that the flexible member constituting the buffer section is formed in a plate shape, and that the buffer section is formed by stacking multiple flexible members.

In other words, if the buffer section is configured with multiple laminated flexible members, the number of flexible members can be adjusted to easily adjust the internal dimensions of the buffer section, i.e., the dimensions and flexibility of the space that contains the electrochemical element.

In the present invention, it is preferable that the housing contains a plurality of the electrochemical elements in a stacked state.

Even when multiple electrochemical elements are used, they are stacked on the housing via a flexible buffer section for positioning, which allows for a wider tolerance for dimensional accuracy during manufacturing of each electrochemical element, making it easier to manufacture the electrochemical elements and improving the yield of the electrochemical elements.

In the present invention, it is preferable that the plate-shaped flexible member constituting the buffer section is arranged around the electrochemical elements with its plate-shaped surface aligned with the stacking direction of the electrochemical elements.

According to this configuration, by providing the buffer portion made of a plate-like flexible member between the housing and the plurality of electrochemical elements, it is easy to position each electrochemical element when housing it in the housing.
Furthermore, by providing the buffer section, external forces acting on the housing are absorbed by the buffer section, thereby suppressing acceleration forces and impact forces on the electrochemical elements, and thus suppressing positional displacement.
The housing and each electrochemical element thermally expand due to heat generation during use of the electrochemical module. If each electrochemical element is directly installed inside the housing without disposing a buffer section, there is a risk of defects such as deformation and damage occurring to the electrochemical element. In contrast, since the buffer section is disposed between at least a part of the periphery of each electrochemical element and the housing as described above, the thermal expansion of each electrochemical element and the housing can be absorbed, and the risk of defects such as deformation and damage occurring to each electrochemical element can be reduced.

In the present invention, it is preferable that the buffer portion is made of an electrically insulating material.

An example of an electrically insulating material is soft mica. If the buffer section is made of an inexpensive material such as soft mica, even when electrical insulation is required between electrochemical elements, there is no need to use expensive materials such as ceramics, which helps to reduce costs.

In the present invention, it is preferable that the housing is made of metal.

Because the housing is made of metal, it is robust. This improves the strength of the electrochemical module that includes the housing.

As a means for achieving the above-mentioned objective, the electrochemical device according to the present invention is characterized in that it has at least the electrochemical module and a fuel converter that generates a reducing component to be supplied to the electrochemical module or converts a gas containing a reducing component generated by the electrochemical module.

According to the above characteristic configuration, when the electrochemical module is operated as a fuel cell, it can be configured to generate hydrogen using a fuel converter such as a reformer 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 module that is excellent in durability, reliability, and performance. In addition, it becomes easy to build a system for recycling unused fuel gas circulated from the electrochemical module, thereby realizing a highly efficient electrochemical device.
On the other hand, when the electrochemical module is operated as an electrolysis cell, 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 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 module by the above-mentioned electrolysis. This makes it possible to circulate the hydrocarbons generated by the fuel converter to the electrochemical module, or to extract them from the system/apparatus and use them as fuel or chemical raw materials.

As a means for achieving the above-mentioned objective, the electrochemical device according to the present invention is characterized in that it has at least the above-mentioned electrochemical module and a power converter that extracts power from the electrochemical module or passes power to the electrochemical module.

According to this configuration, the power converter extracts the power generated by the electrochemical module or passes the power to the electrochemical module. This allows the electrochemical module to function as a fuel cell or an electrolysis cell as described above. Therefore, according to the above configuration, it is possible to provide an electrochemical module 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 inverter can boost the electric output obtained from the electrochemical module, which has excellent durability, reliability, and performance, and convert DC to AC, making it easier to use the electric output obtained from the electrochemical module, which is preferable. In addition, when used for electrolysis, an electrochemical device can be constructed that can obtain DC from an AC power source and supply DC power to an electrochemical element or an electrochemical module, which is preferable.

As a means for achieving the above-mentioned objective, the characteristic configuration of the energy system according to the present invention is that it has the above-mentioned electrochemical module or the above-mentioned electrochemical device, and a waste heat utilization section that reuses the heat discharged from the electrochemical module or the electrochemical device.

The above characteristic configuration has an exhaust heat utilization section that reuses heat discharged from the electrochemical module or the electrochemical device, making it possible to realize an energy system that is excellent in durability, reliability, and performance, as well as 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 power by utilizing the combustion heat of unused fuel gas discharged from the electrochemical device.

As a means for achieving the above-mentioned objective, the solid oxide fuel cell according to the present invention is characterized in that it is provided with the above-mentioned electrochemical module, and a power generation reaction occurs in the electrochemical module.

According to this configuration, a power generation reaction can be performed as a solid oxide fuel cell equipped with an electrochemical module with excellent durability, reliability, and performance, so 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 be constructed in a fuel cell system that uses hydrocarbon gas such as city gas as raw fuel, and the heat required for converting the raw fuel into hydrogen can be supplied by the exhaust heat of the fuel cell, 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 the effect of suppressing Cr volatilization from the electrochemical module is enhanced, 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 the effect of suppressing Cr volatilization can be further enhanced.

As a means for achieving the above-mentioned objective, the solid oxide electrolysis cell according to the present invention is characterized in that it is equipped with the above-mentioned electrochemical module and causes an electrolytic reaction in the electrochemical module.

This configuration allows gas to be generated through an electrolytic reaction as a solid oxide electrolysis cell equipped with an electrochemical module 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 the electrochemical module 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

The electrochemical module, electrochemical device, energy system, solid oxide fuel cell, and solid oxide electrolysis cell of the present invention are described below. Note that although preferred embodiments are described below, each of these embodiments is described to more specifically illustrate the present invention, and various modifications are possible within the scope of the invention, and the present invention is not limited to the following description. Note that when expressing 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.

The electrochemical element, electrochemical module, electrochemical device, and energy system will be described below with reference to Figures 1 to 12.

(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 is provided at one end with a first through portion 41 which forms 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 direction of penetrating the surface into the internal flow passage A1, and is provided at the other end with a second through portion 51 which forms a discharge passage 5 through which the first gas which has passed through the internal flow passage A1 flows outward in the direction of penetrating the surface of the plate-shaped support (see Figures 1, 3, 8, and 9; it will also be understood that the supply passages 4, etc. and the discharge 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 for 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, a 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 temperature cycle of low and high temperatures is repeated. This is preferable because it is possible to realize an electrochemical element A with 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 sintered metal, foam metal, or the like.

The second plate-like body 2 is formed in a corrugated shape to form an internal flow path A1 with multiple 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 portion 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 portion 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; it is also 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 is preferably a heat-resistant metal, and it is more preferable that it is 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 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 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 reduce the amount of expensive electrode layer material used to reduce costs while ensuring sufficient electrode performance. 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.

As the material of the electrode layer 31, for example, a composite material such as NiO-GDC, Ni-GDC, NiO-YSZ, Ni-YSZ, CuO-CeO ₂ , or Cu-CeO ₂ can be used. In these examples, GDC, YSZ, and CeO ₂ can 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 a firing process 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 pulse 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. This is preferable because it is possible to prevent damage to the first plate-like body 1 and suppress interdiffusion of elements between the first plate-like body 1 and the electrode layer 31, thereby realizing an electrochemical element A with excellent durability. Furthermore, the use of a low-temperature firing method is even more preferable because it makes it easier to handle the raw materials.

(Middle class)
The intermediate layer 34 can be formed in 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 continuously increase 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, the electrolyte layer 32 may be provided on top of the electrode layer 31 and the intermediate layer, and a gasket or the like may be provided around the periphery.

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, pulsed 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 and has high airtightness and 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 that is airtight and has high 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-layer structure, it is preferable that at least a part of the electrolyte layer 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, it is easy to form an electrolyte layer that is dense, airtight, and has high gas barrier properties, even when the electrolyte layer is constructed in a multi-layer 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 ensure sufficient performance while reducing the amount of expensive reaction prevention layer material used and reducing costs. 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 method will be described 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 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 formation 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 the intermediate layer 34 or the reaction prevention layer 35 is not provided, or both of them 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, 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 disposed 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 a manner such that the electrochemical elements A are simply contacted to each other to make the electrical connection, or a method of applying a surface pressure to the contact surface or interposing a highly electrically conductive material to reduce the 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 of each electrochemical element facing upward, and the first through portion 41 and the second through portion 51 are stacked (assembled) with the first annular sealing portion 42 and the second annular sealing portion 52 interposed between each first through portion 41 and second through portion 51, thereby resulting in 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 Figures 1, 11 and 12, the electrochemical module M includes a housing B 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.

Examples of materials for the case B include ferritic stainless steel, martensitic stainless steel, or a composite of these and ceramics. These materials have a smaller thermal expansion coefficient than austenitic stainless steel, and the thermal expansion coefficient of ferritic stainless steel is about 11×10 ⁻⁶ /°C for SUS430. The thermal expansion coefficient of martensitic stainless steel is about 10.4×10 ⁻⁶ /°C for SUS403 and SUS420J1, and about 10.1×10 ⁻⁶ /°C for SUS410 and SUS440C. However, the case B is not limited to this, and it is preferable to select a material that has a smaller thermal expansion coefficient than the flat plate member 220 and has excellent corrosion resistance. Therefore, the electrochemical module M is robust.

The material of the electrochemical element A is preferably the same as that of the housing B. In other words, the materials of the electrochemical element A and the housing B preferably have the same thermal expansion coefficient as that of the housing B. The housing B and the electrochemical element A each thermally expand due to heat generated during use of the electrochemical module M. Since the electrochemical element A is built into the housing B, if the thermal expansion coefficients of the housing B and the electrochemical element A differ significantly, there is a risk that defects such as deformation or damage will occur in the electrochemical element A. In contrast, as described above, the housing B and the electrochemical element A have approximately the same thermal expansion coefficients, and therefore thermally expand to the same extent. Therefore, the difference in thermal expansion between the electrochemical element A and the housing B is kept small, and the risk of defects such as deformation or damage occurring in the electrochemical element A can be suppressed.

Furthermore, in the case of a configuration in which multiple electrochemical elements A are stacked, such as the electrochemical element stack S, when the electrochemical module M is in use, a temperature difference may occur between the multiple electrochemical elements A, resulting in a difference in the amount of expansion of each electrochemical element A. Even in such a case, since the buffer section 300 is disposed between the periphery of the multiple electrochemical elements A and the housing B, the expansion of each of the multiple electrochemical elements A can be absorbed by the buffer section, and the risk of defects such as deformation or damage occurring to each electrochemical element A can be reduced.

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 at both ends in the stacking direction of the electrochemical elements A of the electrochemical element stack S. An output section 8 is extended from the current collectors 81, 82 and can be freely connected to a power supply destination outside the housing B. The current collectors 81, 82 accommodate the electrochemical element stack S airtightly in the housing B, and the current collectors 81, 82 are arranged to function as buffer sections for each electrochemical element A.

In the case B, a buffer portion 300 is disposed between the case B and the periphery of the electrochemical device A.
Specifically, as shown in Figures 1, 11 and 12, the electrochemical element stack S is mounted inside a housing B such that the periphery of each electrochemical element A of the electrochemical element stack S is in contact with a buffer section 300. Note that Figures 2 to 9 are cross-sectional views of Figure 1, and Figure 10 is an enlarged view of a main portion, but the buffer section 300 and the housing B are omitted in Figures 2 to 10.

The housing B is provided with a support part B1 integrally therewith. The support part B1 is provided so as to protrude from the inner surface of the housing B. The buffer part 300 is disposed at a predetermined position inside the housing B in the longitudinal direction by being supported by the support part B1. On the other hand, in the lateral direction, the buffer part 300 is disposed at a predetermined position inside the housing B by being supported by the inner wall of the housing B. The support part B1 may be provided only in a portion corresponding to the lower part of the buffer part 300, may be provided only in a portion corresponding to the upper part of the buffer part 300, or may be provided in a portion corresponding to the entire height direction of the buffer part 300. When the support part B1 is provided in a portion corresponding to the entire height direction of the buffer part 300, an opening communicating with the second gas supply port 301 and the second gas exhaust port 302 described later is provided. The buffer part 300 may also be disposed at a predetermined position inside the housing B in the lateral direction by the support part B1 provided so as to protrude from the inner surface of the housing B. The support part B1 may also be configured in the same manner as the support part B1 described above.

Even if the electrochemical element stack S is constructed by stacking multiple electrochemical elements A, they are stacked on the housing B via the buffer section 300, which is flexible in terms of positioning. This makes it easy to manufacture because the tolerance for dimensional accuracy during manufacturing of each electrochemical element A can be widened. As a result, the yield of electrochemical elements A can be improved.

The buffer section 300 is a plate-shaped flexible member that extends along the stacking direction of each electrochemical element A in the electrochemical element stack S. The flexible member is a plate made of a material that has excellent electrical insulation, heat resistance, and compression resistance, for example, soft mica. If the buffer section 300 is formed from an inexpensive material that has electrical insulation properties such as soft mica, even when electrical insulation between electrochemical elements A is required, there is no need to use expensive materials such as ceramics, making it possible to reduce costs.

The soft mica plates constituting the buffer section 300 surround the four sides of the electrochemical element stack S and are arranged so as to be close to or in contact with the electrochemical element stack S. The buffer section 300 may be composed of four plates arranged parallel to each of the four sides, or the four plates may be connected together to form an integrated structure. The buffer section 300 may also be provided only in the portions corresponding to the corners or sides of the electrochemical element stack S.

The buffer section 300 may be configured by stacking multiple flexible members. When the buffer section 300 is configured by stacking multiple flexible members, the number of flexible members can be adjusted to easily adjust the inner dimensions of the buffer section 300, i.e., the dimensions and flexibility of the electrochemical element stack S, i.e., the storage space for the stacked multiple electrochemical elements A.

If the buffer section 300 has a Young's modulus of 10 MPa or more and 35 MPa or less, the electrochemical element can be positioned easily and misalignment is further suppressed. The buffer section preferably has a Young's modulus of 15 MPa or more, and more preferably has a Young's modulus of 18 MPa or more. The buffer section 300 preferably has a Young's modulus of 30 MPa or less, and more preferably has a Young's modulus of 20 MPa or less.

When the thickness of the buffer section 300 is 0.1% or more and 10% or less of the in-plane length of the electrochemical element A, the electrochemical element A can be easily positioned and misalignment is further suppressed. The thickness of the buffer section 300 is preferably 0.3% or more, and more preferably 0.5% or more. The thickness of the buffer section is preferably 5% or less, and more preferably 2% or less.

By having the buffer section 300 made of a material with a certain degree of flexibility, such as soft mica, external forces acting on the housing are absorbed by the buffer section 300. This reduces acceleration and impact forces on the electrochemical element A, and prevents it from shifting out of position.

As shown in Figures 1, 11 and 12, the buffer section 300 has a second gas supply port 301 that supplies a second gas from the second gas supply section 71 into the storage space R of the electrochemical element A surrounded by the buffer section 300, and a second gas exhaust port 302 that exhausts the second gas from the storage space R to the second gas exhaust section 72. The buffer section 300 airtightly surrounds the electrochemical element stack S with respect to the housing B, except for the second gas supply port 301 and the second gas exhaust port 302.

Such a buffer section 300 can improve the airtightness of the space in which electrochemical element A is housed, and the first and second gases required for electrochemical element A do not leak, making it possible to conserve the supply amount.

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.
10 shows an electrochemical element A with a cross section including the internal flow path A1 and an electrochemical element A with a cross section including the flow section A2 arranged for convenience, and 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 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. The fuel gas further advances through the internal flow path A1 together with the electrochemically reacted fuel gas, passes through the junction section A13 and the second through-hole section 51, advances 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 electrochemically reacted fuel gas 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 device 100 and energy system Z can be constructed using the electrochemical module M described above.

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.

<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 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 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 from the combustion exhaust gas exhaust passage 116 to the heat exchanger 200. 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 module M.

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 reaction heat generated by the reaction occurring in the fuel converter 25 with water and vaporizes 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 the electrochemical module M of 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 with a plurality of elements in 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 an 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 portion 41 and the second through portion 51 are provided in pairs at both ends of the rectangular plate-like support body, but the present invention is not limited to providing the first through portion 41 and the second through portion 51 at both ends, and two or more pairs may be provided. In addition, the first through portion 41 and the second through portion 51 do not have to be provided in pairs. Thus, one or more first through portion 41 and one or more second through portion 51 may be provided.
Furthermore, the plate-like support 10 is not limited to a rectangular shape, but may have various other shapes such as a square shape, a circle shape, etc.

(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 formed 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 paths A11 are formed by forming the second plate-like body 2 in a corrugated shape from the distribution portion A12 to the junction portion A13. As shown in FIG. 5, the sub-flow paths 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 path A11 is formed by extending a corrugated plate along the gas flow direction shown in FIG. 1. The sub-flow paths A11 may be formed from a series of corrugated plate-like bodies between the distribution portion A12 and the junction portion A13, or may be composed of two or more corrugated plate-like bodies. The sub-flow paths 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 electrochemical modules, electrochemical devices, energy systems, solid oxide fuel cells, and solid oxide electrolysis cells.

1: First plate-like body 1A: Gas flow permitting portion 2: Second plate-like body 3: Electrochemical reaction portion 4: Supply path 5: Discharge path 8: Output portion 9: Distribution chamber 10: Plate-like support 31: Electrode layer (first electrode, second electrode)
32: Electrolyte layer 33: Counter electrode layer (first electrode, second electrode)
41: First penetration part (penetration part)
42: First annular seal portion 51: Second penetration portion (penetration portion)
52: second annular seal portion 61: first gas supply portion 71: second gas supply portion 100: electrochemical device 102: reformer 103: fuel supply portion 104: inverter 300: buffer portion 301: second gas supply port 302: second gas exhaust port A: electrochemical element A1: internal flow path A11: sub-flow path A12: distribution portion A2: flow portion B: housing B1: support portion M: electrochemical module S: electrochemical element stack Z: energy system

Claims (13)

a flat-plate electrochemical element in which an electrolyte layer and a first electrode and a second electrode, respectively disposed on either side of the electrolyte layer, are formed along a substrate;
A housing surrounding the electrochemical device;
a buffer portion disposed between at least a portion of the periphery of the electrochemical element and the housing;
the housing and the electrochemical element have substantially the same coefficient of thermal expansion;
The substrate is a metal plate-shaped support for an electrochemical module. The electrochemical module according to claim 1, wherein the flexible member constituting the buffer section has a Young's modulus of 10 MPa or more and 35 MPa or less. The electrochemical module according to claim 1 or 2, wherein the flexible member constituting the buffer portion is formed in a plate shape, and the thickness of the flexible member is 0.1% to 10% of the length of the electrochemical element in the planar direction. The electrochemical module according to any one of claims 1 to 3, wherein the flexible member constituting the buffer section is formed in a plate shape, and the buffer section is formed by stacking multiple flexible members. The electrochemical module according to any one of claims 1 to 4, wherein the housing contains a plurality of the electrochemical elements in a stacked state. The electrochemical module according to any one of claims 1 to 5, wherein the plate-shaped flexible member constituting the buffer section is arranged around the electrochemical elements with its plate-shaped surface aligned along the stacking direction of the electrochemical elements. The electrochemical module according to any one of claims 1 to 6 , wherein the buffer section is made of an electrically insulating material. The electrochemical module according to any one of claims 1 to 7 , wherein the housing is made of metal. An electrochemical device comprising at least the electrochemical module according to any one of claims 1 to 8 , and a fuel converter that generates a reducing component to be supplied to the electrochemical module, or that converts a gas containing a reducing component generated in the electrochemical module. 9. An electrochemical device comprising at least the electrochemical module according to claim 1 , and a power converter for extracting electric power from the electrochemical module or for transmitting electric power to the electrochemical module. An energy system comprising: an electrochemical module according to any one of claims 1 to 8 ; or an electrochemical device according to claim 9 or 10 ; and an exhaust heat utilization section that reuses heat exhausted from the electrochemical module or the electrochemical device. A solid oxide fuel cell comprising the electrochemical module according to any one of claims 1 to 8 , wherein an electric power generating reaction occurs in the electrochemical module. A solid oxide electrolysis cell comprising the electrochemical module according to any one of claims 1 to 8 , in which an electrolytic reaction occurs in the electrochemical module.

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