Electrochemical module, solid oxide fuel cell, solid oxide electrolysis cell, electrochemical device, and energy system

Abstract

To provide a method for improving the supply of gas to an electrochemical reaction portion of an electrochemical element.SOLUTION: An electrochemical module M includes a connector C having electrical conductivity and gas permeability, and a plurality of electrochemical elements A stacked with the connector C sandwiched therebetween. The electrochemical element A includes a plate-shaped support 10 having an internal flow path on the inside, a gas flow-permitting portion 1A that allows gas to pass between the outside of the plate-shaped support 10 and the internal flow path A1, and an electrochemical reaction portion 3. The connector C is disposed between the plate-shaped support 10 of the electrochemical element A and a counter electrode layer 33 of another electrochemical element A such that gas that has flowed through the inside of the connector C is supplied to the counter electrode layer 33.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to an electrochemical module, a solid oxide fuel cell, a solid oxide electrolysis cell, an electrochemical device, and an energy system. [Background technology]

[0002] Patent Document 1 discloses an electrochemical element that can be used as a solid oxide fuel cell. The electrochemical element (A) in Patent Document 1 includes a metal support (10) that is made up of a first plate-like body (1) that is a flat plate and a second plate-like body (2) that is a corrugated plate. Fuel gas passes through the space between the first plate-like body and the second plate-like body.

[0003] When this electrochemical element is used as a fuel cell, the electrochemical elements are stacked to form an electrochemical module. The lower end of the second plate-like body, i.e., the apex of the corrugation, is joined to the upper surface of the electrochemical reaction section (3) of another electrochemical element. The second plate-like body electrically joins the two electrochemical elements and forms an air flow path between the second plate-like body and the electrochemical reaction section. In other words, air passes through a long and narrow flow path between the recess of the second plate-like body, which is a corrugated plate, and the electrochemical reaction section. The air in the flow path comes into contact with the surface of the electrochemical reaction section, causing an electrochemical reaction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 189915 Summary of the Invention [Problem to be solved by the invention]

[0005] As described below, the electrochemical module described in Patent Document 1 has room for improvement in terms of the supply of gas to the electrochemical reaction section.

[0006] First, gas is unlikely to be supplied from the gas flow path to the portion of the electrochemical reaction section that is joined to the second plate-like body.

[0007] Secondly, in a long and narrow flow channel, the flow velocity near the wall surface is smaller than the flow velocity in the center. In other words, the flow velocity is likely to be non-uniform inside the long and narrow flow channel, which tends to result in non-uniform supply of gas to the electrochemical reaction section.

[0008] Thirdly, the presence of a member (first annular seal portion (42)) on the upstream side of the second plate-like body reduces the flow rate of the gas behind the member (downstream side). In other words, the flow rate of the gas tends to become non-uniform along a direction intersecting the direction of the gas flow (the width direction or short side direction of the electrochemical element). This tends to result in non-uniform supply of the gas to the electrochemical reaction section.

[0009] An object of the present invention is to provide a method for improving the supply of gas to an electrochemical reaction section of an electrochemical element. [Means for solving the problem]

[0010] As a means for solving the above-mentioned problems, the electrochemical module of the present invention comprises a conductive and breathable connector, and a plurality of electrochemical elements stacked with the connector sandwiched between them, the electrochemical elements comprising a plate-shaped support having an internal flow path on the inside, a gas flow-permitting portion that allows gas to pass between the outside of the plate-shaped support and the internal flow path, an electrode layer, a counter electrode layer, and an electrolyte layer sandwiched between the electrode layer and the counter electrode layer, and an electrochemical reaction portion formed on the outer surface of the plate-shaped support by stacking the electrode layer, the electrolyte layer, and the counter electrode layer in a state in which the electrode layer covers all or a part of the gas flow-permitting portion, and the connector is disposed between the plate-shaped support of one electrochemical element and the counter electrode layer of another electrochemical element such that gas that has flowed through the inside of the connector is supplied to the counter electrode layer.

[0011] According to the above features, a plurality of electrochemical elements are stacked with conductive and breathable connectors sandwiched between them. Gas flowing through the inside of the connectors is supplied to the counter electrode layer of the electrochemical reaction section. Since the connectors in contact with the electrochemical reaction section are breathable, the supply of gas to the electrochemical reaction section is made uniform. In other words, the supply of gas to the electrochemical reaction section of the electrochemical element can be improved.

[0012] In the present invention, it is preferable to further include a first gas supply unit that supplies a first gas to the internal flow path, and a second gas supply unit that supplies a second gas different from the first gas to the connector.

[0013] According to the above features, the first gas supplied to the internal flow path is supplied to the electrode layer of the electrochemical reaction section through the gas flow permitting section. The second gas supplied to the connector is supplied to the counter electrode layer of the electrochemical reaction section. This makes it possible to improve the supply of the second gas to the electrochemical reaction section of the electrochemical element. This improves the performance of the electrochemical module.

[0014] In the present invention, the direction in which the second gas flows in the connecting body is defined as the flow direction, and the present invention further includes a specific member that is arranged upstream of the connecting body in the flow direction and in a position that overlaps with the connecting body when viewed in the flow direction, and it is preferable that a recess is formed at the upstream end of the connecting body in the flow direction, the recess being recessed toward the downstream side of the flow direction, and the recess is in a position that overlaps with the specific member when viewed in the flow direction.

[0015] If the connecting body does not have a recess, the second gas is less likely to flow into the portion of the connecting body downstream of the specific member. As a result, the flow rate of the second gas in that portion is smaller than in other portions. This results in unevenness in the amount of the second gas supplied to the electrochemical reaction portion. According to the above feature, since the connecting body has a recess, the second gas is more likely to flow into the portion of the connecting body downstream of the specific member. This makes it possible to uniform the flow rate of the second gas in the connecting body.

[0016] In the present invention, the specific member is preferably a tube that connects the internal flow path of the electrochemical element with the internal flow path of another electrochemical element.

[0017] According to the above feature, the second gas easily flows into the portion of the connector downstream of the tube, thereby making it possible to make the flow rate of the second gas in the connector uniform.

[0018] In the present invention, the direction in which the second gas flows in the connecting body is defined as the flow direction, and the connecting body further includes a specific member that is arranged upstream of the flow direction relative to the connecting body and at a position that overlaps with the connecting body when viewed in the flow direction, and the connecting body preferably includes a first portion and a second portion having a flow resistance of the second gas smaller than that of the first portion, and the second portion is preferably at a position that overlaps with the specific member when viewed in the flow direction.

[0019] The second gas is less likely to flow into the portion of the connecting body downstream of the specific member. If the connecting body does not have the second portion and the flow resistance is uniform, the flow rate of the second gas in that portion will be smaller than in other portions. Therefore, non-uniformity occurs in the amount of the second gas supplied to the electrochemical reaction section. According to the above feature, since the connecting body has the second portion with a smaller flow resistance of the second gas, the second portion reduces the decrease in the flow rate of the second gas in the portion of the connecting body downstream of the specific member. This makes it possible to uniformize the flow rate of the second gas in the connecting body.

[0020] In the present invention, it is preferable that the density of the second portion is smaller than the density of the first portion.

[0021] According to the above feature, since the density of the second portion is lower than the density of the first portion, the flow resistance of the second portion is lower than that of the first portion, thereby making it possible to make the flow rate of the second gas in the connecting body uniform.

[0022] In the present invention, the specific member is preferably a tube that connects the internal flow path of the electrochemical element with the internal flow path of another electrochemical element.

[0023] According to the above feature, a decrease in the flow rate of the second gas in the portion of the connector downstream of the tube is reduced by the second portion, thereby making it possible to uniform the flow rate of the second gas in the connector.

[0024] In the present invention, the direction in which the second gas flows in the connecting body is defined as the flow direction, and the present invention further includes a specific member that is arranged upstream of the connecting body in the flow direction and at a position that overlaps with the connecting body when viewed in the flow direction, and the connecting body is arranged to be divided in a direction intersecting the flow direction, sandwiching a space extending along the flow direction, and the space is preferably at a position that overlaps with the specific member when viewed in the flow direction.

[0025] If the connecting body is not divided and does not have a space, the second gas is less likely to flow into the portion of the connecting body downstream of the specific member. As a result, the flow rate of the second gas in that portion is smaller than in other portions. Therefore, non-uniformity occurs in the amount of the second gas supplied to the electrochemical reaction portion. According to the above feature, the space is located at a position that overlaps with the specific member when viewed in the flow direction. The flow resistance of the space is smaller than the flow resistance of the connecting body. Therefore, the space reduces the decrease in the flow rate of the second gas in the portion of the connecting body downstream of the specific member. This makes it possible to uniformly supply the second gas from the connecting body and the space to the electrochemical reaction portion.

[0026] In the present invention, the specific member is preferably a tube that connects the internal flow path of the electrochemical element with the internal flow path of another electrochemical element.

[0027] According to the above feature, the effect of a decrease in the flow rate of the second gas in the portion of the connector downstream of the tube is reduced by the presence of the space, thereby making it possible to make the flow rate of the second gas in the connector uniform.

[0028] In the present invention, the connector is preferably any one of a metallic mesh body, a porous metal, a metallic nonwoven fabric, and a porous ceramic.

[0029] According to the above features, a connector having electrical conductivity and gas permeability can be manufactured easily and at low cost, and the supply of gas to the electrochemical reaction section can be made uniform.

[0030] In the present invention, it is preferable that the connector is made of a metal containing Cr and has a surface coated with a coating that suppresses scattering of Cr.

[0031] According to the above-mentioned features, it is possible to suppress scattering of Cr from the connector, thereby improving the durability of the electrochemical module.

[0032] As a means for solving the above-mentioned problems, the solid oxide fuel cell of the present invention is characterized in that it comprises any one of the electrochemical modules described above, and causes a power generation reaction in the electrochemical element.

[0033] According to the above features, a power generation reaction can be performed as a solid oxide fuel cell equipped with an electrochemical element having excellent durability, reliability and performance, so that a highly durable and high-performance solid oxide fuel cell can be obtained. In addition, a solid oxide fuel cell that can be operated at a temperature range of 650°C or more during rated operation is more preferable because it can construct a system that can cover the heat required for converting a raw fuel into hydrogen in a fuel cell system that uses a hydrocarbon gas such as city gas as a raw fuel, and therefore can improve 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 a metal-supported electrochemical element 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.

[0034] As a means for solving the above-mentioned problems, the solid oxide electrolysis cell of the present invention is characterized in that it comprises any one of the electrochemical modules described above, and causes an electrolytic reaction in the electrochemical element.

[0035] According to the above features, gas can be generated by an electrolytic reaction as a solid oxide electrolysis cell equipped with an electrochemical element that is excellent in durability, reliability, and performance, so that a highly durable, high-performance solid oxide electrolysis cell can be obtained.

[0036] As a means for solving the above-mentioned problems, the electrochemical device of the present invention is characterized by having at least any one of the electrochemical modules described above, and a fuel converter that generates a reducing component to be supplied to the electrochemical element or the electrochemical module, or converts a gas containing a reducing component generated in the electrochemical element or the electrochemical module.

[0037] According to the above features, when the electrochemical element or electrochemical module is operated as a fuel cell, it can be configured to generate hydrogen using a fuel converter such as a reformer based on natural gas or the like supplied using existing raw fuel supply infrastructure such as city gas, thereby realizing an electrochemical device equipped with an electrochemical element or electrochemical module with excellent durability, reliability and performance. In addition, it becomes easier to build a system for recycling unused fuel gas circulated from the electrochemical module, thereby realizing a highly efficient electrochemical device. On the other hand, when the electrochemical element or electrochemical module is operated as an electrolysis cell, a gas containing water vapor or carbon dioxide is passed through the electrode layer, and a voltage is applied between the electrode layer and the counter electrode layer. Then, electrons e - reacts with water molecules H2O and carbon dioxide molecules CO2 to produce hydrogen molecules H2, carbon monoxide CO, and oxygen ions O 2- The generated oxygen ions O 2- The oxygen ions O move through the electrolyte layer to the counter electrode layer. 2- releases electrons and becomes oxygen molecules O2. Through the above reaction, when gas containing water vapor flows, water molecules H2O are decomposed into hydrogen H2 and oxygen O2, and when gas containing carbon dioxide molecules CO2 flows, they are electrolyzed into carbon monoxide CO and oxygen O2. Therefore, when gas containing water vapor and carbon dioxide molecules CO2 is circulated, a fuel converter can be provided that synthesizes various compounds such as hydrocarbons from hydrogen and carbon monoxide generated in the electrochemical element or electrochemical module by the above-mentioned electrolysis. This makes it possible to circulate the hydrocarbons generated by the fuel converter to the electrochemical element or electrochemical module, or to extract them from this system / device and use them as fuel or chemical raw materials.

[0038] As a means for solving the above-mentioned problems, the electrochemical device of the present invention is characterized by having at least any one of the electrochemical modules described above, and a power converter that extracts power from the electrochemical element or the electrochemical module, or that supplies power to the electrochemical element or the electrochemical module.

[0039] According to the above features, the power converter extracts power generated by the electrochemical element or electrochemical module, or passes power to the electrochemical element or electrochemical module. As a result, the electrochemical element or electrochemical module functions as a fuel cell or an electrolysis cell. Thus, the above configuration can provide an electrochemical element or the like that can improve the efficiency of converting chemical energy such as fuel into electrical energy, or converting electrical energy into chemical energy such as fuel. For example, when an inverter is used as a power converter, the electric output obtained from an electrochemical element or electrochemical module having excellent durability, reliability, and performance can be boosted or DC can be converted to AC by the inverter, which is preferable since it makes it easier to utilize the electric output obtained from the electrochemical element or electrochemical module. Also, when used for electrolysis, it is preferable since it is possible to construct an electrochemical device that can obtain DC from an AC power source and supply DC power to an electrochemical element or electrochemical module.

[0040] As a means for solving the above-mentioned problems, the energy system of the present invention is characterized by having at least the above-mentioned electrochemical device and a waste heat utilization section that reuses heat discharged from the electrochemical device.

[0041] According to the above features, since the electrochemical device and the waste heat utilization unit that reuses the heat discharged from the electrochemical device are included, it is possible to realize an energy system that is excellent in durability, reliability, and performance as well as energy efficiency. Note that 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. [Brief description of the drawings]

[0042] [Figure 1] Schematic diagram of an electrochemical device [Diagram 2] Cross-sectional view of Fig. 1 along line II-II [Diagram 3] III-III plane view in Fig. 1 [Figure 4] Cross-sectional view of FIG. 1 taken along the line IV-IV [Diagram 5] VV cross section in Figure 1 [Figure 6] Cross section taken along the line VI-VI in Fig. 1 [Figure 7] Cross-sectional view taken along the line VII-VII in FIG. [Figure 8] Cross-sectional view taken along the line VIII-VIII in FIG. [Figure 9] Enlarged view of the electrochemical reaction section [Figure 10] Schematic diagram of the electrochemical module [Figure 11] Energy system diagram [Figure 12] Schematic diagram of alternative energy systems [Figure 13] Schematic diagram showing the shape of the connector [Figure 14] FIG. 13 is a schematic diagram showing a modified example of the connector; [Figure 15] FIG. 1 shows a first shape model. [Figure 16]FIG. 2 shows a second shape model. [Figure 17] A diagram showing the third shape model [Figure 18] Graph showing analysis results of flow velocity distribution at a first position of a first geometric model [Figure 19] Graph showing analysis results of flow velocity distribution at a second position of the first geometric model [Figure 20] Graph showing analysis results of flow velocity distribution at the third position of the first geometric model [Figure 21] Graph showing the analysis result of the flow velocity distribution at the first position of the second geometric model [Figure 22] Graph showing analysis results of flow velocity distribution at a second position of a second geometric model [Figure 23] Graph showing the analysis result of the flow velocity distribution at the third position of the second shape model [Figure 24] Graph showing the analysis result of the flow velocity distribution at the first position of the third geometric model [Diagram 25] Graph showing the analysis result of the flow velocity distribution at the second position of the third shape model [Figure 26] Graph showing the analysis result of the flow velocity distribution at the third position of the third shape model [Figure 27] FIG. 13 is a schematic diagram showing another modified example of the connector; [Figure 28] FIG. 13 is a schematic diagram showing another modified example of the connector; [Figure 29] FIG. 13 is a schematic diagram showing another modified example of the connector; [Diagram 30] FIG. 13 is a schematic diagram showing another modified example of the connector; [Diagram 31] FIG. 13 is a schematic diagram showing another modified example of the connector; [Diagram 32] FIG. 13 is a schematic diagram showing another modified example of the connector; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] First embodiment The electrochemical module, electrochemical device, energy system, solid oxide fuel cell, and solid oxide electrolysis cell of the present invention will be described below. Note that, although preferred examples are described below, each of these examples is described to more specifically illustrate the present invention, and various modifications are possible within the scope of the present invention, and the present invention is not limited to the following description. Note that, when expressing the positional relationship of layers, for example, the electrolyte layer side as viewed from the electrode layer is called "upper" or "upper side", and the first plate-like body side is called "lower" or "lower side", etc.

[0044] (Electrochemical element) As shown in Figures 1 to 8, 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 8). 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 penetrating the surface to 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 penetrating the surface of the plate-shaped support 10 (see Figures 1, 3, 7 and 8; it will also be understood that the supply passages 4, etc. and the discharge passages 5, etc. are symmetrical and have similar structures).

[0045] (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 alloy, etc. are used. In particular, an alloy containing Cr is preferably used. In this embodiment, the first plate-shaped body 1 uses an Fe-Cr alloy containing 18% by mass or more and 25% by mass or less of Cr, but particularly preferred are an Fe-Cr alloy containing 0.05% by mass or more of Mn, an Fe-Cr alloy containing 0.15% by mass or more and 1.0% by mass or less of Ti, an Fe-Cr alloy containing 0.15% by mass or more and 1.0% by mass or less of Zr, an Fe-Cr alloy containing Ti and Zr and having a total content of Ti and Zr of 0.15% by mass or more and 1.0% by mass or less, and an Fe-Cr alloy containing 0.10% by mass or more and 1.0% by mass or less of Cu.

[0046] The second plate-like body 2 is welded and integrated with the first plate-like body 1 at the peripheral edge 1a in a state where it is overlapped with the first plate-like body 1 to form the plate-like support body 10 (see Figs. 2 to 8). The second plate-like body 2 may be divided into a plurality of pieces relative to the first plate-like body 1, or conversely, the first plate-like body 1 may be divided into a plurality of pieces relative to the second plate-like body 2. In addition, when integrating the first plate-like body 2 and the second plate-like body 2, other means such as adhesion or fitting can be used instead of welding, and as long as the internal flow path A1 can be formed by separating it from the outside, the two may be integrated at a portion other than the peripheral edge 1a.

[0047] The first plate-like body 1 is generally plate-shaped. In this embodiment, the first plate-like body 1 is a flat plate. The first plate-like body 1 has a gas flow-permitting portion 1A having a large number of through holes 11 penetrating the front surface and the back surface (see Figs. 5 to 8). 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. The gas flow-permitting portion 1A is preferably provided in an area of ​​the first plate-like body 1 that is smaller than the area in which the electrode layer 31 is provided.

[0048] The first plate-like body 1 is provided on its surface with a metal oxide layer 12 (see FIG. 9, described later) as a diffusion suppression layer. That is, the diffusion suppression layer is formed between the first plate-like 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-like 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-like body 1 and the electrode layer 31. For example, when ferritic stainless steel containing Cr is used as the first plate-like body 1, the metal oxide layer 12 is mainly Cr oxide. The metal oxide layer 12, which is mainly composed of Cr oxide, suppresses the diffusion of Cr atoms and the like of the first plate-like 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.

[0049] 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 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 may be formed by plating and oxidation treatment. Furthermore, the metal oxide layer 12 may contain a highly conductive spinel phase, etc.

[0050] 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) or 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 not easily damaged even when a temperature cycle of low and high temperatures is repeated. Therefore, it is preferable because an electrochemical element A excellent in long-term durability can be realized. The first plate-like body 1 has a plurality of through holes 11 provided through the front surface and the back surface. For example, the through holes 11 can be provided in the first plate-like body 1 by mechanical, chemical, or optical drilling processing. The through holes 11 have a function of transmitting gas from the back surface of the first plate-like body 1 to the front surface. It is also possible to use a porous metal to give the first plate-like body 1 gas permeability. For example, the first plate-like body 1 can be made of a sintered metal, a foamed metal, or the like.

[0051] The second plate-like body 2 is generally plate-shaped. The second plate-like body 2 has a recess that becomes the internal flow path A1 when joined to the first plate-like body 1. The material of the second plate-like body 2 is preferably a heat-resistant metal, and is more preferably the same material as the first plate-like body 1 from the viewpoints of reducing the thermal expansion difference with the first plate-like body 1 and ensuring the reliability of joining such as welding.

[0052] (Electrochemical reaction section, electrode layer) As shown in Figs. 5 to 9, the electrode layer 31 can be provided in a thin layer state on the front surface of the first plate-like body 1 in an area larger than the area where the through holes 11 are provided. When the electrode layer 31 is provided as a thin layer, the thickness can be, for example, about 1 µm to 100 µm, preferably 5 µm to 50 µm. With such a thickness, it is possible to ensure sufficient electrode performance while reducing the amount of expensive electrode layer material used to reduce costs. The entire area where the through holes 11 are provided is covered with the electrode layer 31. That is, the through holes 11 are formed inside the area where the electrode layer 31 is formed in the first plate-like body 1. In other words, all the through holes 11 are provided facing the electrode layer 31.

[0053] 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 material constituting the layer to the space, and can be expressed as (1-porosity), and is equivalent to the relative density.

[0054] Examples of materials for the electrode layer 31 include NiO-GDC, Ni-GDC, NiO-YSZ, Ni-YSZ, and CuO. - CeO2, Cu - A composite material such as CeO2 can be used. In these examples, GDC, YSZ, and CeO2 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 firing in a low-temperature range without firing in a high-temperature range higher than 1100°C), a spray coating method (such as a thermal spray method, an aerosol deposition method, an aerosol gas deposition method, a powder jet deposition method, a particle jet deposition method, and a cold spray method), a PVD method (such as a sputtering method and 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. Therefore, it is preferable because it is possible to realize an electrochemical element A with excellent durability without damaging the first plate-like body 1 and suppressing the interdiffusion of elements between the first plate-like body 1 and the electrode layer 31. Furthermore, it is even more preferable to use a low-temperature firing method because it makes it easier to handle the raw materials.

[0055] (Middle class) The intermediate layer 34 can be formed as a thin layer on the electrode layer 31 in a state where it covers the electrode layer 31. When it 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. Such a thickness makes it possible to ensure sufficient performance while reducing the amount of expensive material used for the intermediate layer 34, thereby cutting costs. 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 as the material for the intermediate layer 34. In particular, ceria-based ceramics are preferably used.

[0056] 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. By using these film formation processes that can be used in a low-temperature range, the intermediate layer 34 can be obtained 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, it is more preferable to use a low-temperature firing method because it makes it easier to handle the raw materials.

[0057] The intermediate layer 34 preferably has oxygen ion (oxide ion) conductivity. It is 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.

[0058] The electrode layer 31 may 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 make the content ratio, density, strength, etc. of the aggregate of the cermet material higher in the portion of the electrode layer 31 adjacent to the electrolyte layer 32 (upper portion) than in the portion of the electrode layer 31 adjacent to the first plate-like body 1 (lower portion).

[0059] (electrolyte layer) 5 to 9, the electrolyte layer 32 is formed as a thin layer on the electrode layer 31 and the intermediate layer 34, covering the electrode layer 31 and the intermediate layer 34. Alternatively, the electrolyte layer 32 may be formed as a thin film having a thickness of 10 μm or less. 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.

[0060] 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 holes 11 are provided. In other words, the through holes 11 are formed inside the area in the first plate-like body 1 in which the electrolyte layer 32 is formed.

[0061] Additionally, gas leakage from the electrode layer 31 and the intermediate layer (not shown) can be suppressed around the electrolyte layer 32. In detail, 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-holes 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. In this embodiment, the electrolyte layer 32 covers the entire periphery of the electrode layer 31. However, the electrolyte layer 32 may be provided on the electrode layer 31 and the intermediate layer, and a gasket or the like may be provided around the periphery.

[0062] 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 a SOFC, a material that can exhibit high electrolyte performance even in a high temperature range of about 650°C or more, such as YSZ, is used as the material for electrolyte layer 32, a hydrocarbon-based raw fuel such as city gas or LPG is used as the raw fuel for the system, and the raw fuel is converted into SOFC anode gas by steam reforming or the like. In this way, a highly efficient SOFC system can be constructed in which the heat generated in the SOFC cell stack is used to reform the raw fuel gas.

[0063] The electrolyte layer 32 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 exceeding 1100°C), a spray coating method (thermal spraying, aerosol deposition, aerosol gas deposition, powder jet deposition, particle jet deposition, cold spray, etc.), a PVD method (sputtering, pulse laser deposition, etc.), a CVD (chemical vapor deposition) method, etc.). By using these film formation processes that can be used in a low-temperature range, it is possible to obtain an electrolyte layer 32 that is dense and has high airtightness and gas barrier properties without firing in a high-temperature range exceeding 1100°C, for example. Therefore, damage to the first plate-like body 1 can be suppressed, and interdiffusion of elements between the first plate-like body 1 and the electrode layer 31 can be suppressed, thereby realizing an electrochemical element A with excellent performance and durability. In particular, it is preferable to use a low-temperature firing method or a spray coating method, etc., because it is possible to realize a low-cost element. Furthermore, spray coating is more preferable because it is easy to obtain a dense electrolyte layer 32 that has high airtightness and gas barrier properties in a low temperature range.

[0064] The electrolyte layer 32 is densely configured to prevent 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 configured in a multi-layered form, it is preferable that at least a part of the layers 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. When such a dense electrolyte layer is included as part of the electrolyte layer 32, it becomes easier to form an electrolyte layer 32 that is dense and has high airtightness and gas barrier properties, even if the electrolyte layer 32 is composed of multiple layers.

[0065] (Reaction prevention layer) The reaction prevention layer 35 can be formed in a thin layer state on the electrolyte layer 32. When the reaction prevention layer 35 is a thin layer, the thickness can be, for example, about 1 μm to 100 μm, preferably about 2 μm to 50 μm, and more preferably about 3 μm to 15 μm. With such a thickness, it is possible to reduce the amount of expensive reaction prevention layer material used, thereby reducing costs, while ensuring sufficient performance. The material of the reaction prevention layer may be any material that can prevent the reaction between the components of the electrolyte layer 32 and the components of the counter electrode layer 33, and for example, a ceria-based material is used. In addition, a material containing at least one element selected from the group consisting of Sm, Gd, and Y is preferably used as the material of the reaction prevention layer 35. It is preferable that the reaction prevention layer 35 contains at least one element selected from the group consisting of Sm, Gd, and Y, and the total content of these elements is 1.0 mass% or more and 10 mass% or less. By introducing the reaction prevention layer 35 between the electrolyte layer 32 and the counter electrode layer 33, the reaction between the constituent material of the counter electrode layer 33 and the constituent material of the electrolyte layer 32 is effectively suppressed, and the long-term stability of the performance of the electrochemical element A can be improved. The reaction prevention layer 35 is preferably formed by a method capable of forming the layer at a processing temperature of 1100° C. or less, since this 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 reaction prevention layer 35 can be formed by a method capable of forming the layer at a processing temperature of 1100° C. or less, since this can suppress damage to the first plate-like body 1 and 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 reaction prevention layer 35 can be formed by a method appropriately using a low-temperature firing method (for example, a wet method using a firing treatment in a low-temperature range that does not include a firing treatment 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. 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.

[0066] (Counter electrode layer) As shown in Figs. 5 to 9, 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 reduce the amount of expensive counter electrode layer material used to reduce costs while ensuring sufficient electrode performance. 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.

[0067] The counter electrode layer 33 is preferably formed by a suitable method capable of forming the layer at a processing temperature of 1100° C. or less, since it is possible to suppress damage to the first plate-like body 1 and also to suppress interdiffusion of elements between the first plate-like body 1 and the electrode layer 31, thereby realizing an electrochemical element A having excellent performance and durability. For example, the counter electrode layer 33 can be formed by a suitable method such as a low-temperature firing method (e.g., a wet method using a firing process in a low-temperature range without firing at a high temperature range exceeding 1100° C.), 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 PDV method (a sputtering method, a pulsed laser deposition method, etc.), a CVD method, etc. In particular, it is preferable to use a low-temperature firing method or a spray coating method, etc., since it is possible to realize a low-cost element. Furthermore, it is even more preferable to use a low-temperature firing method, since it is easier to handle the raw materials.

[0068] By configuring the electrochemical reaction unit 3 in this manner, for example, a fuel gas containing hydrogen as a first gas is circulated from the rear surface of the first plate-like body 1 through the through holes 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 O2 contained in the air is converted into electrons e in the counter electrode layer 33. - reacts with oxygen ions O 2- The oxygen ion O 2- The hydrogen H2 contained in the flowing fuel gas is converted into oxygen ions O 2- reacts with water H2O and electrons e - When an electrolyte material that conducts hydrogen ions is used for the electrolyte layer 32, hydrogen H2 contained in the fuel gas flowing through the electrode layer 31 is converted into electrons e - releases hydrogen ions H + The hydrogen ion H + moves through the electrolyte layer 32 to the counter electrode layer 33. In the counter electrode layer 33, oxygen O2 and hydrogen ions H + , electronic e - reacts to produce water HO. The above reaction generates an electromotive force as an electrochemical output between the electrode layer 31 and the counter electrode layer 33. In this case, the electrode layer 31 functions as the fuel electrode (anode) of the fuel cell, and the counter electrode layer 33 functions as the air electrode (cathode).

[0069] 5 to 8, in this embodiment, 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, as shown in FIG.

[0070] (Manufacturing method of electrochemical reaction part) Next, a description will be given of a manufacturing method of the electrochemical reaction section 3. Note that since an intermediate layer 34 and a reaction prevention layer 35 described below are omitted in Figs. 5 to 8, the description will be given mainly with reference to Fig. 9.

[0071] (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 in 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, 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. Whichever method is used, 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.

[0072] When the electrode layer forming step is carried out by a low-temperature firing method, the step is specifically carried out as follows. First, a material powder of the electrode layer 31 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 and fired at 800°C to 1100°C.

[0073] (Diffusion suppression layer formation step) During the firing process in the electrode layer formation step described above, a metal oxide layer 12 (diffusion-suppressing 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 of elements is highly suppressed, and a good-quality metal oxide layer 12 (diffusion-suppressing layer) with low resistance is formed, which is preferable. The electrode layer formation step may include a separate diffusion-suppressing layer formation step, including a case where a coating method is used without firing. In either case, it is preferable to perform the process at a processing temperature of 1100°C or less, at which damage to the first plate-like body 1 can be suppressed.

[0074] (Intermediate layer formation 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. Whichever method is used, 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.

[0075] 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), roll pressing, RIP (Rubber Isostatic Pressing), or the like. The intermediate layer 34 is preferably fired 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. The intermediate layer 34 is more preferably fired at 1050°C or less, and even more preferably fired 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. Also, 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 performed by lapping, leveling, cutting and polishing the surface, or the like.

[0076] (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 where any method is used, 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.

[0077] In order to form a high-quality electrolyte layer 32 that is dense and has high airtightness and gas barrier properties in 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.

[0078] (Reaction prevention layer formation 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, or the like), a PVD method (a sputtering method, a pulse laser deposition method, or the like), a CVD method, or the like. In any case, in order to suppress deterioration of the first plate-like body 1, it is preferable 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 treatment or a cutting / polishing treatment of the surface may be performed after the formation of the reaction prevention layer 35, or a press process may be performed after the wet formation and before firing.

[0079] (Counter electrode layer formation 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. Whichever method is used, 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.

[0080] In this manner, the electrochemical reaction portion 3 can be manufactured.

[0081] In addition, the electrochemical reaction section 3 may be configured to have either or both of the intermediate layer 34 and the reaction prevention layer 35. That is, the electrode layer 31 and the electrolyte layer 32 may be formed in contact with each other, or the electrolyte layer 32 and the counter electrode layer 33 may be formed in contact with each other. In this case, the above-mentioned manufacturing method omits the intermediate layer forming step and the reaction prevention layer forming step. It is also possible to add a step of forming another layer or to stack a plurality of layers of the same type, but in either case, it is preferable to perform the process at a temperature of 1100°C or less.

[0082] (Electrochemical element stack) As shown in FIG. 10, the electrochemical element stack S (electrochemical element assembly, electrochemical module M) comprises a connector C having electrical conductivity and breathability, and a plurality of electrochemical elements A stacked with the connector C sandwiched between them.

[0083] The connector C is disposed between the plate-like support 10 of the electrochemical element A and the counter electrode layer 33 of another electrochemical element A such that the gas (second gas) flowing through the inside of the connector C is supplied to the counter electrode layer 33. The connector C also electrically connects the plate-like support 10 of the electrochemical element A and the counter electrode layer 33 of the other electrochemical element A.

[0084] In other words, the electrochemical element stack S has a plurality of electrochemical elements A. Adjacent electrochemical elements A are arranged such that the plate-like support 10 constituting one electrochemical element A faces the plate-like support 10 constituting the other electrochemical element A.

[0085] Specifically, a plurality of electrochemical elements A are aligned with their first through-holes 41 and second through-holes 51 aligned in a straight line, with the electrochemical reaction portion 3 of each electrochemical element A facing upward. Then, a plurality of electrochemical elements A are stacked (assembled) with the first annular seal portion 42 interposed between the first through-holes 41 and the second annular seal portion 52 interposed between the second through-holes 51.

[0086] The first annular seal portion 42 and the second annular seal portion 52 are cylindrical members formed of an insulating ceramic material such as alumina, a metal coated with this, or a material such as mica fiber, glass, etc. The first annular seal portion 42 and the second annular seal portion 52 physically connect and electrically insulate the adjacent electrochemical elements A.

[0087] The supply passage 4 is formed by a first through-hole 41 of the plate-like support 10 and a cylindrical first annular seal portion 42. An annular bulge a is formed around a portion of the first plate-like body 1 that comes into contact with the first annular seal portion 42 (first through-hole 41). The bulge a makes it easy to position the first annular seal portion 42 in a direction along the surface of the first plate-like body 1.

[0088] The discharge passage 5 is formed by the second through-hole 51 of the plate-like support 10 and a second cylindrical annular seal portion 52 .

[0089] (Electrochemical Module) As shown in FIG. 11, the electrochemical module M includes a housing B made of an insulator that houses the electrochemical element stack S, a first gas supply unit 61 that distributes a first gas from the outside of the housing B to the internal flow path A1 via the supply path 4, a first gas discharge unit 62 that distributes the first gas after the reaction, a second gas supply unit 71 that distributes a second gas from the outside of the housing B to the connector C, a second gas discharge unit 72 that distributes 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.

[0090] A distribution chamber 9 is provided in the housing B, which distributes and distributes the second gas circulated from the second gas supply unit 71 to the connectors C. The distribution chamber 9 is a space located on the side (lateral side) of the electrochemical element stack S that serves as an inlet or outlet of the circulation part of the electrochemical element stack S.

[0091] The electrochemical element stack S is housed within the case B in a state where it is sandwiched between a pair of current collectors 81, 82. An output unit 8 is extended from the current collectors 81, 82 and is freely connected to a power supply destination outside the case B. The current collectors 81, 82 are provided so as to accommodate the electrochemical element stack S in an airtight manner within the case B and to function as buffer materials for each electrochemical element A.

[0092] When fuel gas is supplied from the first gas supply unit 61 and air is supplied from the second gas supply unit 71, the fuel gas enters as shown by the dashed arrow in FIG. 10, and air enters as shown by the solid arrow.

[0093] The fuel gas circulating from the first gas supply section 61 is guided to the supply channel 4 through the first through portion 41 of the uppermost electrochemical element A of the electrochemical element stack S, and flows through the supply channel 4 partitioned by the first annular seal portion 42 to the internal flow paths A1 of all the electrochemical elements A.

[0094] The fuel gas that has entered the internal flow path A1 can enter the electrode layer 31 via the gas flow permissive portion 1A. The fuel gas and the fuel gas that has undergone the electrochemical reaction further advance through the internal flow path A1 and enter the exhaust path 5 formed by the second through-hole portion 51 and the second annular seal portion 52. Then, together with the fuel gas from the other electrochemical elements A, it is circulated to the outside of the casing B through the first gas exhaust portion 62.

[0095] The air circulated from the second gas supply unit 71 flows temporarily into the distribution chamber 9, and then passes through the connectors C disposed between the electrochemical devices A.

[0096] The air circulated from the second gas supply unit 71 passes through the distribution chamber 9 and enters the connecting body C, and can then enter the counter electrode layer 33. The air, together with the air that has undergone an electrochemical reaction, further travels through the connecting body C along the electrochemical reaction unit 3, and is circulated outside the casing B through the second gas exhaust unit 72.

[0097] The electricity generated in the electrochemical reaction section 3 in accordance with the flow of the fuel gas and air is connected in series between the current collectors 81, 82 by contact between the electrochemical reaction section 3 of the adjacent electrochemical element A and the second plate-like body 2 via the connector C, and the combined output is taken out from the output section 8.

[0098] The electrochemical device 100 and the energy system Z can be constructed using the electrochemical module M described above.

[0099] (Energy systems, electrochemical devices) FIG. 11 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 a waste heat utilization section for reusing 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 electricity from the electrochemical module M.

[0100] In detail, the electrochemical device 100 includes a desulfurizer 101, a reforming water tank 105, a vaporizer 106, a reformer 102, a blower 107, a combustion unit 108, an inverter 104, a control unit 110, and an electrochemical module M.

[0101] The desulfurizer 101 removes (desulfurizes) sulfur compounds contained in a hydrocarbon-based 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, and generates a reformed gas containing hydrogen.

[0102] The electrochemical module M generates power by electrochemical reaction using the reformed gas circulated from the reformer 102 and 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 combustible components in the reaction exhaust gas.

[0103] The inverter 104 adjusts the output power of the electrochemical module M to have the same voltage and frequency as the power received from a commercial grid (not shown). The control unit 110 controls the operation of the electrochemical device 100 and the energy system Z.

[0104] The reformer 102 performs a reforming process of the raw fuel using the combustion heat generated by the combustion of the reaction exhaust gas in the combustion section 108 .

[0105] The raw fuel is circulated to the desulfurizer 101 through a raw fuel supply passage 112 by the operation of a boost pump 111. The reforming water in the reforming water tank 105 is circulated to the vaporizer 106 through a reforming water supply passage 114 by the operation of a 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 have been merged outside the casing B are circulated to the vaporizer 106.

[0106] The reforming water is vaporized in the vaporizer 106 to become water vapor. The raw fuel containing water vapor produced in the vaporizer 106 is circulated to the reformer 102 through a water vapor-containing raw fuel supply passage 115. The raw fuel is steam reformed in the reformer 102 to produce a reformed gas (a first gas having a reducing component) mainly composed of hydrogen gas. The reformed gas produced in the reformer 102 is circulated to the electrochemical module M through a fuel supply unit 103.

[0107] The reaction exhaust gas is combusted in the combustion section 108 to become a combustion exhaust gas, which is sent from the combustion exhaust gas discharge 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 discharge passage 116, and reduces the carbon monoxide, hydrogen, and other reducing components contained in the combustion exhaust gas by combustion.

[0108] The heat exchanger 200 exchanges heat between the combustion exhaust gas generated by the combustion in the combustion section 108 and the cold water passing through it, thereby generating hot water. That is, the heat exchanger 200 operates as a waste heat utilization section that reuses the heat discharged from the electrochemical device 100.

[0109] 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 part of the reaction exhaust gas circulating from the first gas discharge section 62 to the outside of the housing B may be recycled by joining it to any one of the locations 100, 101, 103, 106, 112, 113, and 115 in Fig. 11. The reaction exhaust gas contains the remaining hydrogen gas that was not used in the reaction in the electrochemical element A. In the reaction exhaust gas utilization section, the remaining hydrogen gas is utilized to utilize heat through combustion or to generate electricity through a fuel cell or the like, thereby making effective use of energy.

[0110] Fig. 12 shows an example of the energy system Z and the electrochemical device 100 when the electrochemical reaction unit 3 is operated as an electrolysis cell. In this system, supplied water and carbon dioxide are electrolyzed in the electrochemical reaction unit 3 to generate hydrogen, carbon monoxide, etc. Furthermore, hydrocarbons and the like are synthesized in the fuel converter 25. Energy efficiency can be improved by configuring the heat exchanger 24 in Fig. 12 to operate as an exhaust heat utilization unit that exchanges heat between the reaction heat generated by the reaction in the fuel converter 25 and water to vaporize it, and the heat exchanger 23 in Fig. 12 to operate as an exhaust heat utilization unit that exchanges heat between the exhaust heat generated by the electrochemical element A and water vapor and carbon dioxide to preheat them. 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 the electrochemical device 100, the energy system Z, and the like that can improve the efficiency of converting electrical energy into chemical energy such as fuel.

[0111] (Connector) The connector C of this embodiment will be described with reference to FIGS.

[0112] In the following description, the direction in which the second gas flows in the electrochemical element A and the connector C is referred to as a flow direction X. As shown in Fig. 10, the second gas flows from the second gas supply portion 71 to the second gas discharge portion 72. Therefore, the second gas flows along the longitudinal direction of the electrochemical element A from the side of the first through-hole 41 and the first annular seal portion 42 to the side of the second through-hole 51 and the second annular seal portion 52.

[0113] In the drawing, the upstream side of the flow direction X is indicated by an arrow X1, and the downstream side is indicated by an arrow X2. The direction perpendicular to the flow direction X is called the cross direction Y. The right side of the downstream side X2 of the flow direction X is indicated by an arrow Y1 as the Y1 side, and the left side is indicated by an arrow Y2 as the Y2 side.

[0114] As described above, the connector C is a member having electrical conductivity and air permeability. In the example of FIG. 13, the connector C is rectangular in plan view and covers the entire electrochemical reaction section 3 of the electrochemical element A. In the illustrated example, the end of the connector C is located outside the end of the electrochemical reaction section 3. In other words, the connector C is larger than the electrochemical reaction section 3. The shape of the connector C in plan view is not limited to the illustrated example. Modified examples of the connector C will be described later.

[0115] The connector C may be a metal or an electrically conductive ceramic. For example, the connector C is a metal mesh, a porous metal, a metal nonwoven fabric, or a porous ceramic.

[0116] When the connector C is a metal containing Cr, it is preferable that the connector C is provided with a coating that suppresses scattering and abnormal oxidation of Cr. The coating is, for example, Mn-Co oxide, Mn-Cu oxide, or Ni-Co oxide.

[0117] The thickness of the connector C is, for example, 0.8 mm. The thickness of the connector C is preferably 0.3 mm or more and 1.5 mm or less.

[0118] The porosity of the connector C is, for example, 70%. The porosity of the connector C is preferably 40% or more and 90% or less.

[0119] As shown in FIG. 10, an electrochemical module M includes the above-mentioned connector C and a plurality of electrochemical elements A stacked with the connector C sandwiched therebetween. A first gas is supplied from a first gas supply unit 61 to the electrode layer 31 via an internal flow path A1. A second gas is supplied from a second gas supply unit 71 to the connector C. The second gas passes through the connector C and reaches the counter electrode layer 33. That is, the second gas is supplied from the connector C to the counter electrode layer 33. Since the connector C has air permeability, the second gas is uniformly supplied from a portion in contact with the connector C to the electrochemical reaction unit 3.

[0120] Sealing members for preventing gas leakage may be disposed on both outer sides in the Y direction of the electrochemical reaction unit 3 and the connector C. The sealing members may extend to the ends of the plate-like support 10 in the X direction, or may extend to the ends of the electrochemical reaction unit 3 in the X direction.

[0121] (Modification of Connector) Another example of a connector C is shown in Fig. 14. This connector C is generally rectangular in plan view, and has a recess C1 at the end on the upstream side (X1 side) of the flow direction X. The recess C1 is recessed toward the downstream side (X2) of the flow direction X. In other words, the recess C1 is recessed toward the downstream side (X2) of the flow direction X.

[0122] The recess C1 is located at a position overlapping with the first annular seal portion 42 when viewed along the flow direction X. In other words, at least a portion of the recess C1 is located on the downstream side X2 in the flow direction X of the first annular seal portion 42.

[0123] In the illustrated example, the width (size in the Y direction) of the recess C1 is larger than the width (size in the Y direction) of the first annular seal portion 42. The depth (size in the X direction) of the recess C1 is smaller than the vertical width (size in the X direction) of the first annular seal portion 42. A part of the first annular seal portion 42 is located inside the recess C1. The X1 side end of the connecting body C is located on the X1 side of the X2 side end of the first annular seal portion 42.

[0124] When the connecting body C does not have a recess as in the illustrated example of FIG. 13 described above, the second gas does not easily flow into the portion of the connecting body C downstream of the first annular seal portion 42 (specific member). This makes the flow rate of the second gas in that portion smaller than in other portions. This causes unevenness in the amount of the second gas supplied to the electrochemical reaction portion 3. According to the example of FIG. 14, since the connecting body C has the recess C1, the second gas easily flows into the portion of the connecting body C downstream of the first annular seal portion 42 (specific member). This makes it possible to uniformize the flow rate of the second gas in the connecting body C.

[0125] (Computer simulation confirms the effect of connectors) The effect of the connector C was confirmed using a computer simulation. The gas flow velocity distribution was calculated by fluid analysis for the first shape model SM1, the second shape model SM2, and the third shape model SM3 shown in Figures 15-17. Since the electrochemical element A and the connector C are symmetrical in the Y direction, each shape model was modeled after the shape of the half of the Y2 side of the electrochemical element A. The conditions of the fluid analysis are shown below. Please note that the directions of the arrows X1, X2, Y1, and Y2 in Figures 15-17 are reversed from those in Figures 13 and 14.

[0126] In the figures, the plain areas surrounded by solid lines and the shaded areas (Figs. 16 and 17) are areas through which gas can flow. The shaded areas correspond to connector C. The shaded areas are areas through which gas flow is prohibited.

[0127] Gas flows in from end 121 on the X1 side of the geometric model, passes through intermediate gas flow section 122, and flows out from end 123 on the X2 side of the geometric model. Defects 124 and 125 appear in each geometric model. Defect 124 is a portion through which gas cannot pass, and corresponds to first annular seal section 42. Defect 125 is a portion through which gas cannot pass, and corresponds to second annular seal section 52. Although only plan views are shown in FIGS. 15-17, each geometric model has a thickness that mimics that of an actual electrochemical element A.

[0128] 15 is modeled after the gas flow path (hereinafter, may be referred to as the "conventional example") disclosed in International Publication No. 2019 / 189915 (Patent Document 1 mentioned above). The gas flow section 122 of this first shape model SM1 is a plurality of flow paths extending along the X direction and aligned along the Y direction.

[0129] The second shape model SM2 in FIG. 16 imitates the connector C, the space on the X1 side of the connector C, and the space on the X2 side of the connector C in the example in FIG.

[0130] The third shape model SM3 in Fig. 17 mimics the connector C, the space on the X1 side of the connector C, and the space on the X2 side of the connector C in the example of Fig. 14. A recess 122a corresponding to the recess C1 of the connector C is formed at the end on the X1 side of the gas flow section 122.

[0131] In the second shape model SM2 in Figure 16 and the third shape model SM3 in Figure 17, the gas flow section 122 corresponding to the connector C has a void ratio set to 0.5, and the fluid resistance is set so that the overall pressure loss of the shape model is approximately the same as that of the first shape model SM1.

[0132] The gas flowing in from the end 121 was air at 700° C. The gas flow rate was set to a value that would generate power at a current density of 0.5 A / cm with a gas utilization rate of 30%.

[0133] The analysis results of each shape model are explained below with reference to the graphs in Figures 18 to 26. The graphs show the flow velocity distribution along the Y direction at the following three positions: (1) First position (P1 in the figure): the inlet side of the gas flow section 122, i.e., the end on the X1 side (2) Second position (P2 in the figure): 5 mm from the second position on the X2 side (3) Third position (P3 in the figure): Center of the gas flow section 122 in the X direction

[0134] When each geometric model is applied to the electrochemical module M, the gas flow velocity distribution shown in each graph corresponds to the amount of gas supplied to the electrochemical reaction section 3. At positions where the flow velocity is zero, gas cannot be supplied to the electrochemical reaction section 3. At positions where the flow velocity is high, gas (more specifically, reaction components in the gas that are subjected to the electrochemical reaction) is supplied in greater quantities than at positions where the flow velocity is low. It is preferable that the reaction in the electrochemical reaction section 3 occurs uniformly throughout the electrochemical reaction section 3. To achieve this, it is preferable that the gas used in the reaction is supplied uniformly throughout the electrochemical reaction section 3. Therefore, it is preferable that the flow velocity distribution in the gas flow section 122 of each geometric model is uniform.

[0135] In addition, two series of flow velocities with different magnitudes appear in each graph. For example, in the graph of the third position of the second shape model (Fig. 23), a series of flow velocities of approximately 4 m / s and approximately 3 m / s appear. This is because when the flow velocity distribution is taken in the width direction (Y direction), a flow velocity distribution in which the maximum value is at the center in the thickness direction also occurs in the thickness direction of each shape model.

[0136] Moreover, the magnitude of the flow velocity of the second and third shape models (approximately 4 m / s) is less than half of the magnitude of the flow velocity of the first shape model (approximately 10 m / s), because the gas flow section 122 of the first shape model is divided into multiple thin flow paths.

[0137] [Analysis results of the first shape model] Periodic peaks in the flow velocity appeared at the first position (FIG. 18), the second position (FIG. 19), and the third position (FIG. 20). This is because the gas flow section 122 of the first shape model SM1 (FIG. 15) has a form of multiple flow paths extending along the X direction and aligned along the Y direction, and gas does not flow between the flow paths, so the flow velocity is zero. Since the flow velocity is not uniform in the gas flow section 122, it is believed that the supply of gas to the electrochemical reaction section 3 is also not uniform.

[0138] At the second position (FIG. 19) and the third position (FIG. 20), the flow velocity near the end on the Y1 side (corresponding to the center of the electrochemical element A in the Y direction) is approximately 1 m / s slower than the flow velocity at other positions. This is believed to be because the end on the Y1 side is downstream of the defect 124 (a gas-impermeable portion corresponding to the first annular seal portion 42).

[0139] [Analysis results of the second shape model] At the first position (FIG. 21), the second position (FIG. 22), and the third position (FIG. 23), no periodic peaks like those in the first shape model appeared, and the graph of the flow velocity distribution had a smooth shape. Particularly at the third position, the flow velocity was uniform across the entire width (width in the Y direction) of the gas flow section 122. Therefore, by employing the connector C in the example of FIG. 13 described above, it is possible to supply gas to the electrochemical reaction section 3 more uniformly than in the conventional example.

[0140] The decrease in flow velocity near the end on the Y1 side (corresponding to the center of the electrochemical element A in the Y direction) will be examined. At the first position (FIG. 21), the flow velocity near the end on the Y1 side (corresponding to the center of the electrochemical element A in the Y direction) is about 2 m / s smaller than the flow velocity at other positions. At the second position (FIG. 22), a decrease in flow velocity of about 1 m / s is also observed. On the other hand, at the third position (FIG. 23), no decrease in flow velocity occurs. This is considered to be due to the fact that gas can move in the Y direction in the gas flow section 122 of the second shape model. From the above results, it is recognized that the decrease in flow velocity near the end on the Y1 side (corresponding to the center of the electrochemical element A in the Y direction) is improved in the second shape model compared to the first shape model.

[0141] [Analysis results of the third shape model] As with the second shape model, no periodic peaks like those in the first shape model appeared at the first position (FIG. 24), the second position (FIG. 25), and the third position (FIG. 26), and the flow velocity distribution was smooth. Therefore, by adopting the connector C in the example of FIG. 14 described above, it is possible to supply gas to the electrochemical reaction unit 3 more uniformly than in the conventional example.

[0142] The decrease in flow velocity near the end on the Y1 side (corresponding to the center of the electrochemical element A in the Y direction) will be examined. The decrease in flow velocity at the first position (FIG. 24) is approximately 1 m / s, which is an improvement over the second shape model (FIG. 21). The decrease in flow velocity at the second position (FIG. 25) is approximately 0.2 m / s, which is an improvement over the second shape model (FIG. 22). This is believed to be due to the fact that a recess 122a corresponding to the recess C1 of the connector C is formed at the end on the X1 side of the gas flow section 122 of the third shape model. The recess 122a (recess C1) makes it easier for gas to flow into the downstream side of the missing section 124 (first annular seal section 42).

[0143] (Other Modifications of Connector) The form of the connector C is not limited to the example shown in FIG. 13-14.

[0144] 27, an end (side) of the connecting body C overlaps with an end (side) of the electrochemical reaction unit 3 in a planar view. The recess C1 is recessed inward (toward the X2 side) from the end (side) of the electrochemical reaction unit 3. That is, in the illustrated example, the connecting body C does not cover the entire electrochemical reaction unit 3. The electrochemical reaction unit 3 has a portion that is not covered by the connecting body C. The width (size in the Y direction) of the recess C1 is approximately the same as the width of the first annular seal portion 42.

[0145] In the example of FIG. 28, the ends (sides) of the connector C on the X2 side, Y1 side, and Y2 side overlap the ends (sides) of the electrochemical reaction unit 3 in a plan view, and the end on the X1 side is located closer to the X1 side than the end on the X1 side of the electrochemical reaction unit 3. The vertical width (size in the X direction) of the recess C1 is smaller than that of the recess C1 in the example of FIG. 27. The end on the X2 side of the recess C1 is located closer to the X2 side than the end on the X1 side of the electrochemical reaction unit 3. The horizontal width (size in the Y direction) of the recess C1 is approximately the same as the horizontal width of the first annular seal portion 42.

[0146] 29, the ends (sides) of the connecting body C on the X2 side, the Y1 side, and the Y2 side overlap the ends (sides) of the electrochemical reaction unit 3 in a plan view. The X1 side end of the connecting body C is located closer to the X1 side than the X1 side end of the electrochemical reaction unit 3. The X1 side end of the connecting body C protrudes in the X1 direction beyond the X1 side end of the electrochemical reaction unit 3 to near the center of the first annular seal portion 42.

[0147] In the example of FIG. 30, the connector C is divided and arranged in the Y direction intersecting the flow direction X, with a space D extending along the flow direction X between them. More specifically, two split connectors C2 as the connector C are arranged spaced apart in the Y direction. That is, a space D exists between the split connectors C2. The gas that has passed through the split connector C2 and the gas that has passed through the space D are supplied to the electrochemical reaction section 3. Note that the connector C may be divided into three or more pieces, and two or more spaces D may exist between the split connectors C2.

[0148] In the illustrated example, the space D is located at a position overlapping with the first annular seal portion 42 (specific member) when viewed along the flow direction X. In other words, the space D is located downstream X2 of the first annular seal portion 42 in the flow direction X. The gas flow resistance in the space D is smaller than the gas flow resistance in the connecting body C. Therefore, the space D reduces the decrease in the gas flow rate in the portion of the connecting body C downstream of the first annular seal portion 42. This makes it possible to uniformly supply gas from the connecting body C and the space D to the electrochemical reaction unit 3.

[0149] In the example of FIG. 31, the connector C is divided in the Y direction and the X direction. More specifically, the connector C is divided into two in the Y direction and three in the X direction. Six split connectors C2 as the connector C are arranged spaced apart in the Y direction and the X direction. A space D exists between the split connectors C2. The gas that has passed through the split connector C2 and the gas that has passed through the space D are supplied to the electrochemical reaction section 3. Note that the number of divisions of the connector C, i.e., the number of split connectors C2, is not limited to the number in the illustrated example.

[0150] In the illustrated example, the portion of space D extending along the X direction is located at a position overlapping with the first annular seal portion 42 when viewed along the flow direction X. In other words, the portion of space D extending along the X direction is located on the downstream side X2 in the flow direction X of the first annular seal portion 42. The flow resistance of gas in space D is smaller than the flow resistance of gas in the connecting body C. Therefore, the portion of space D in the example of FIG. 31 extending along the X direction can achieve the same effect as space D in the example of FIG. 30 described above.

[0151] In the example of FIG. 32, the connecting body C has a first portion C3 and a second portion C4. The density of the first portion C3 is different from the density of the second portion C4. In the illustrated example, the first portion C3 and the second portion C4 are strip-shaped portions extending along the X direction. The shapes of the first portion C3 and the second portion C4 are not limited to the illustrated example. The first portion C3 may be divided in the X direction, and the second portion C4 may be disposed between the divided first portions C3.

[0152] In the illustrated example, the second portion C4 is located at a position overlapping with the first annular seal portion 42 when viewed along the flow direction X. In other words, the second portion C4 is located downstream X2 of the first annular seal portion 42 in the flow direction X. When the density of the second portion C4 is smaller than that of the first portion C3, the gas flow resistance in the second portion C4 is smaller than the gas flow resistance in the first portion C3. Since the connecting body C has the second portion C4 having a smaller gas flow resistance, the reduction in the gas flow rate in the downstream portion of the first annular seal portion 42 in the connecting body C is reduced by the second portion C4. This makes it possible to uniformize the gas flow rate in the connecting body C.

[0153] The first portion C3 and the second portion C4 may be separate members or may be an integral member. The density may change continuously between the first portion C3 and the second portion C4. That is, a form in which there is no clear boundary between the first portion C3 and the second portion C4 is also possible.

[0154] [Another embodiment] The present invention is not limited to the configurations exemplified in the above-described embodiments. Other representative embodiments of the present invention will be described below.

[0155] (1) In the above embodiment, the electrochemical element A is used in a solid oxide fuel cell as the electrochemical device 100, but the electrochemical element A can also be used in a solid oxide electrolysis cell, an oxygen sensor using a solid oxide, etc. In addition, the electrochemical element A can be used alone, not limited to being combined with a plurality of elements as the electrochemical element stack S or the electrochemical module M.

[0156] (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-CeO2, or Cu-CeO2, 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 of an air electrode and the counter electrode layer 33 can be made of a fuel electrode. That is, the electrode layer 31 is made of a composite oxide such as LSCF or LSM, and the counter electrode layer 33 is made of a composite material such as NiO-GDC, Ni-GDC, NiO-YSZ, Ni-YSZ, CuO-CeO2, or Cu-CeO2. In the electrochemical element A configured in this manner, air can be circulated through the electrode layer 31 to make it an air electrode, and hydrogen gas can be circulated through the counter electrode layer 33 to make it a fuel electrode, so that the electrochemical element A can be used as a solid oxide fuel cell.

[0157] (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, the flow of gas to the electrochemical device A also needs to be changed. 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.

[0158] (4) In the above embodiment, the electrochemical reaction unit 3 is provided on the side of the first plate-like body 1 opposite the second plate-like body 2 to cover the gas flow-permitting portion 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 unit 3 is configured to be disposed in the internal flow path A1.

[0159] (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 10, but the present invention is not limited to providing them at both ends, and two or more pairs may be provided. In addition, the first through portion 41 and the second through portion 51 do not have to be provided in pairs. Therefore, one or more first through portion 41 and one or more second through portion 51 may be provided. Furthermore, the plate-like support 10 is not limited to a rectangular shape, but may have various other shapes such as a square shape, a circle shape, etc.

[0160] (6) The first and second annular seal portions 42, 52 may have any shape as long as they are configured to communicate between the first and second through-holes 41, 51 to prevent gas leakage. In other words, the first and second annular seal portions 42, 52 may have an endless configuration having an opening therein that communicates with 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.

[0161] (7) In the above, the plate-like support 10 is composed of a first plate-like body 1 and a second plate-like body 2. Here, the first plate-like body 1 and the second plate-like body 2 may be composed of separate plate-like bodies, or may be composed of a single plate-like body. For example, the first plate-like body 1 and the second plate-like body 2 are overlapped by folding the single plate-like body. Then, the first plate-like body 1 and the second plate-like body 2 are integrated by welding the peripheral portion 1a or the like. Note that the first plate-like body 1 and the second plate-like body 2 may be composed of a series of seamless plate-like bodies, or may be formed by folding a series of plate-like bodies. 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.

[0162] (8) In the above-described embodiment, all the electrochemical elements A are connected via the connectors C. That is, the connectors C are disposed between all the electrochemical elements A. Some of the electrochemical elements A may be connected via a member (e.g., a corrugated member) different from the connectors C.

[0163] (9) In the above embodiment, the member corresponding to the "specific member" is the first annular seal portion 42, which is a tube. The first annular seal portion 42 may be a cylinder as in the illustrated example, or may be a square tube. In other words, the cross-sectional shape of the first annular seal portion 42 is arbitrary. The "specific member" may be a member different from the first annular seal portion 42. For example, a member such as a spacer sandwiched between the electrochemical elements A, or a protrusion provided on the plate-like support 10 may be the "specific member."

[0164] In addition, the configurations disclosed in the above embodiments can be applied in combination with configurations disclosed in other embodiments as long as no contradiction occurs. In addition, the embodiments disclosed in this specification are examples, and the present invention is not limited to these embodiments, and can be appropriately modified within the scope of the purpose of the present invention. [Industrial Applicability]

[0165] The present invention is applicable to electrochemical modules, solid oxide fuel cells, solid oxide electrolysis cells, electrochemical devices, and energy systems. [Explanation of symbols]

[0166] 1A: Gas flow permitting section 3: Electrochemical reaction section 10: Plate-shaped support 25: Fuel converter 31: Electrode layer 32: Electrolyte layer 33: Counter electrode layer 42: First annular seal portion (specific member) 61: First gas supply section 71: Second gas supply section 100: Electrochemical device 104: Power converter A: Electrochemical element A1: Internal flow path C: Connector C1: Recess C3: First part C4:Second part D: Space M: Electrochemical module X:Flow direction Z: Energy System

Claims

1. A connector having electrical conductivity and air permeability; a plurality of electrochemical elements stacked with the connector therebetween; The electrochemical device comprises: A plate-shaped support having an internal flow path therein; a gas flow permitting portion that allows gas to pass between the outside of the plate-shaped support body and the internal flow path; an electrochemical reaction section including an electrode layer, a counter electrode layer, and an electrolyte layer sandwiched between the electrode layer and the counter electrode layer, the electrode layer, the electrolyte layer, and the counter electrode layer being stacked on an outer surface of the plate-shaped support in a state in which the electrode layer covers all or a part of the gas flow allowing section, The connector is disposed between the plate-like support of the electrochemical element and the counter electrode layer of another electrochemical element such that gas that has passed through the inside of the connector is supplied to the counter electrode layer.

2. A first gas supply unit that supplies a first gas to the internal flow path; The electrochemical module according to claim 1 , further comprising: a second gas supply unit that supplies a second gas different from the first gas to the connection body.

3. The direction in which the second gas flows in the connector is defined as a flow direction, A specific member is further provided that is arranged on the upstream side of the connector in the flow direction and at a position overlapping with the connector as viewed in the flow direction, a recessed portion recessed toward a downstream side in the flow direction is formed at an upstream end portion of the connecting body in the flow direction, The electrochemical module according to claim 2 , wherein the recess is located at a position overlapping with the specific member when viewed in the flow direction.

4. 4. The electrochemical module according to claim 3, wherein the specific member is a tube that connects the internal flow path of the electrochemical element with the internal flow path of another electrochemical element.

5. The direction in which the second gas flows in the connector is defined as a flow direction, A specific member is further provided that is disposed upstream of the connector in the flow direction and at a position overlapping with the connector as viewed in the flow direction, the connecting body includes a first portion and a second portion having a flow resistance of the second gas smaller than that of the first portion, The electrochemical module according to claim 2 , wherein the second portion is positioned so as to overlap the specific member when viewed in the flow direction.

6. 6. The electrochemical module of claim 5, wherein the second portion has a density less than the density of the first portion.

7. 7. The electrochemical module according to claim 6, wherein the specific member is a tube that connects the internal flow path of the electrochemical element with the internal flow path of another electrochemical element.

8. The direction in which the second gas flows in the connector is defined as a flow direction, A specific member is further provided that is arranged on the upstream side of the connector in the flow direction and at a position overlapping with the connector as viewed in the flow direction, The connectors are divided and arranged in a direction intersecting the flow direction with a space extending along the flow direction therebetween, The electrochemical module according to claim 2 , wherein the space is located at a position overlapping the specific member when viewed in the flow direction.

9. 9. The electrochemical module according to claim 8, wherein the specific member is a tube that connects the internal flow path of the electrochemical element with the internal flow path of another electrochemical element.

10. 2. The electrochemical module according to claim 1, wherein the connector is any one of a metallic mesh, a porous metal, a metallic nonwoven fabric, and a porous ceramic.

11. 2. The electrochemical module according to claim 1, wherein the connector is made of a metal containing Cr and has a surface coated with a coating that inhibits Cr from scattering.

12. A solid oxide fuel cell comprising the electrochemical module according to claim 1 , wherein the electrochemical element generates a power generation reaction.

13. A solid oxide electrolysis cell comprising the electrochemical module according to claim 1 , wherein an electrochemical reaction occurs in the electrochemical element.

14. An electrochemical module according to any one of claims 1 to 11; and a fuel converter that generates a reducing component to be supplied to the electrochemical element or the electrochemical module, or that converts a gas containing a reducing component generated in the electrochemical element or the electrochemical module.

15. An electrochemical module according to any one of claims 1 to 11; and a power converter that extracts electric power from the electrochemical element or the electrochemical module, or that passes electric power to the electrochemical element or the electrochemical module.

16. An electrochemical device according to claim 14; and a waste heat utilization section that reuses heat discharged from the electrochemical device.

17. An electrochemical device according to claim 15; and a waste heat utilization section that reuses heat discharged from the electrochemical device.

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