Bonding material, electrochemical module, electrochemical device, solid oxide fuel cell, solid oxide electrolysis cell, energy system, and method for manufacturing electrochemical module

Abstract

To provide a bonding material capable of securing bonding performance even when baked at a low temperature.SOLUTION: A bonding material 10 for bonding an alloy member 26 containing Fe and Cr and an electrochemical element E having a single cell configured by sandwiching an electrolyte layer 4 between an electrode layer 2 and a counter electrode layer 6 has a structure in which a plurality of fine particles having an average particle diameter of 0.1 μm or more and 0.2 μm or less aggregate in a state where the alloy member 26 and the single cell are joined.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] For example, a solid oxide fuel cell (SOFC) is configured as a cell stack in which single cells, each having an electrolyte layer sandwiched between a fuel electrode and an air electrode, are stacked with inter-cell connectors made of alloy materials between them. In this case, a bonding material is used to electrically and physically connect the single cells and the inter-cell connectors. The bonding material is required to have low resistance and high adhesion.

[0003] Common bonding materials include non-metallic oxide materials and precious metal materials such as Ag, Ag-Pd alloys, and Pt. Precious metal materials such as Pt and Ag exhibit low resistance and high adhesion in the operating environment, but Pt is an extremely expensive material, and Ag has issues such as the risk of short circuits due to evaporation and precipitation in insulating parts in the operating environment of SOFCs.

[0004] Non-metallic oxide materials as the bonding material include perovskite-based oxides and spinel-based oxides.

[0005] The perovskite oxide has a composition similar to that of the material used for the air electrode material, and examples of the composition include oxides such as La-Sr-Co-Fe-O, La-Sr-Mn-O, and La-Sr-Ni-O. These materials are preferred because they have affinity with the air electrode, have a matching thermal expansion coefficient, and have high electronic conductivity. Patent Document 1 (JP 2016-195101 A) describes an example in which a conductive ceramic material containing a perovskite oxide containing a metal selected from La, Sr, Pr, Sm, Fe, Co, Mn, and Ni as a bonding material is used as a main material. In Patent Document 1, the bonding material is baked at a temperature of 1000°C to 1150°C.

[0006] Thus, a temperature of 1000°C or higher is generally required to bake the bonding material between the single cell and the cell connection member in a state of close adhesion, and depending on the configuration of the SOFC cell stack, such bonding materials may not be usable due to temperature restrictions. For example, in fuel cells equipped with metal-supported SOFCs or glass seal parts that cannot be subjected to a temperature history of 1000°C or higher, bonding materials that require baking at 1000°C or higher cannot be used due to adverse effects such as sintering of the electrode material.

[0007] In addition, spinel oxides containing one or more transition metals, such as Co-Mn, Cu-Mn, Co-Ni, Co-Ni-Mn, and Ni-Mn, are considered to be candidates for bonding materials, just like perovskite oxides, because they have high electronic conductivity and a thermal expansion coefficient that matches that of cell materials.

[0008] However, the low resistance and high adhesion required of a bonding material are in a trade-off relationship with the sintering temperature. The lower the sintering temperature, the lower the adhesion becomes, which in turn increases the contact resistance. This makes it difficult to reduce the sintering temperature. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2016-195101 A Summary of the Invention [Problem to be solved by the invention]

[0010] As described above, it is desirable for a bonding material for joining an alloy member such as a single cell and an inter-cell connection member that constitutes a fuel cell or the like to ensure bonding performance including electrical performance and physical performance such as low resistance performance and high adhesion performance, even when baking is performed at a low temperature.

[0011] The present invention has been made in view of the above problems, and an object of the present invention is to provide a bonding material, an electrochemical module, an electrochemical device, a solid oxide fuel cell, a solid oxide electrolysis cell, an energy system, and a method for manufacturing an electrochemical module, which are capable of ensuring bonding performance even when baked at a low temperature. [Means for solving the problem]

[0012] A characteristic configuration of the bonding material according to the present invention for achieving the above object is a bonding material for bonding an alloy member containing Fe and Cr to an electrochemical element having a single cell formed by sandwiching an electrolyte layer between an electrode layer and a counter electrode layer, the bonding material comprising: The alloy member and the unit cell have a structure in which a plurality of fine particles having an average particle size of 0.1 μm or more and 0.2 μm or less are aggregated together when the alloy member and the unit cell are bonded together. Here, the bonding material preferably contains Co. The bonding material preferably contains Ni. Furthermore, the bonding material preferably contains a metal oxide containing at least two of Co, Mn, Cu, and Ni. Furthermore, it is preferable that the porosity of the alloy member and the electrochemical element when joined together is 60% or more.

[0013] According to the above characteristic configuration, by using a bonding material having a structure in which multiple microparticles having an average particle size of 0.1 μm or more and 0.2 μm or less are aggregated when the alloy member and the single cell are bonded together, low resistance performance and high adhesion performance can be ensured even when baking at low temperatures. Therefore, it is possible to provide a bonding material that can ensure bonding performance even when baked at a low temperature.

[0014] In order to achieve the above object, the electrochemical module of the present invention has a characteristic configuration in that it comprises the alloy member, the electrochemical element, and the bonding material that bonds between the alloy member and the electrochemical element.

[0015] According to the above characteristic configuration, it is possible to provide an electrochemical module capable of ensuring the bonding performance between the alloy member and the electrochemical element even when baking is performed at a low temperature.

[0016] Another characteristic feature of the electrochemical module according to the present invention is that it includes a plurality of the electrochemical elements, and the plurality of electrochemical elements are electrically connected to each other by the alloy member.

[0017] According to the above characteristic configuration, the above-mentioned electrochemical elements are arranged in a group, so that even if the performance of one electrochemical element that constitutes the electrochemical module is low, the performance of the electrochemical module made up of multiple electrochemical elements can be increased.

[0018] A further characteristic feature of the electrochemical module according to the present invention is that the electrochemical element has a reaction prevention layer between the electrolyte layer and the counter electrode layer.

[0019] According to the above characteristic configuration, a reaction between the components of the electrolyte layer and the components of the counter electrode layer can be prevented, thereby realizing an element with excellent long-term durability.

[0020] Another characteristic feature of the electrochemical module according to the present invention is that the electrochemical device has a metal support that supports the single cell.

[0021] According to the above characteristic configuration, the electrochemical element can be supported by the metal support and its strength can be maintained.

[0022] In order to achieve the above object, a solid oxide fuel cell according to the present invention has a characteristic configuration in that it includes the above electrochemical module, and causes a power generation reaction in the unit cell.

[0023] According to the above characteristic configuration, a power generation reaction can be carried out as a solid oxide fuel cell having an electrochemical module with excellent performance, so that a solid oxide fuel cell with excellent performance can be obtained.

[0024] In order to achieve the above object, a solid oxide electrolysis cell according to the present invention has a characteristic configuration in that it includes the above electrochemical module and causes an electrolytic reaction in the single cell.

[0025] According to the above characteristic configuration, since gas can be generated by electrolytic reaction as a solid oxide electrolysis cell equipped with an electrochemical module with excellent performance, a solid oxide electrolysis cell with excellent performance can be obtained.

[0026] The electrochemical device according to the present invention, which is intended to achieve the above-mentioned object, has a characteristic configuration in that it at least comprises the above-mentioned electrochemical module, and a fuel converter which circulates a gas containing a reducing component through the electrochemical module, or a fuel converter which converts the gas containing a reducing component produced in the electrochemical module.

[0027] According to the above characteristic configuration, the electrochemical module and the fuel converter that circulates a gas containing a reducing component to the electrochemical module are included. Therefore, when the electrochemical module is operated as a fuel cell, a fuel converter such as a reformer is used to generate hydrogen from natural gas or the like supplied using an existing raw fuel supply infrastructure such as city gas, and the hydrogen is then circulated to the fuel cell, thereby realizing an electrochemical device equipped with an electrochemical module with excellent performance.

[0028] Furthermore, according to the above characteristic configuration, the device has an electrochemical module and a fuel converter that converts the gas containing a reducing component generated by the electrochemical module. Therefore, when the electrochemical module is operated as an electrolysis cell, for example, an electrochemical device can be realized in which hydrogen generated by the electrolysis reaction of water is reacted with carbon monoxide or carbon dioxide in the fuel converter to convert it into methane or the like. With such a configuration, an electrochemical device equipped with an electrochemical module with excellent performance can be realized.

[0029] A further characteristic feature of the electrochemical device according to the present invention is that it comprises at least the electrochemical module described above, and a power converter for extracting electric power from the electrochemical module or for supplying electric power to the electrochemical module.

[0030] According to the above characteristic configuration, the power converter extracts the power generated by the electrochemical module or distributes the power to the electrochemical module. As a result, the electrochemical module acts as a fuel cell or an electrolytic cell as described above. Therefore, according to the above characteristic configuration, an electrochemical module 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 can be provided. For example, when an inverter is used as the power converter, the electrical output obtained from the electrochemical module with excellent performance can be boosted by the inverter or DC can be converted into AC, so that the electrical output obtained by the electrochemical module can be easily used, which is preferable. Furthermore, when the electrochemical module is used as an electrolytic cell, it is preferable to construct an electrochemical device that can obtain DC from an AC power source by the power converter and supply DC power to the electrochemical module.

[0031] The energy system according to the present invention for achieving the above object is characterized by having the electrochemical device and a waste heat utilization section that reuses heat discharged from the electrochemical device.

[0032] According to the above-mentioned characteristic configuration, since the electrochemical device and the exhaust 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 performance and energy efficiency. It is also possible to realize a hybrid system with excellent energy efficiency by combining the electrochemical device with a power generation system that generates power by utilizing the combustion heat of unused fuel gas discharged from the electrochemical device.

[0033] The method for producing an alloy member according to the present invention for achieving the above object is characterized in that an alloy member containing Fe and Cr is sandwiched between an electrode layer and a counter electrode layer and a single cell is provided between the alloy member and an electrochemical device having the single cell, the above A method for manufacturing an electrochemical module using a bonding material, comprising the steps of: The method includes a bonding step of disposing the bonding material between the alloy member and the electrochemical element and firing the material at a temperature of less than 1000°C.

[0034] According to the above characteristic configuration, the bonding process in which a bonding material is placed between the alloy member and the electrochemical element and then fired can be performed at a low temperature of less than 1000°C. As a result, adverse effects of heat on the electrochemical module can be reduced. The firing temperature is preferably 900°C or lower, and more preferably 800°C or lower. Such a bonding process in which firing is performed at a low temperature can suppress damage to the electrochemical module and provide a high-performance electrochemical module. In order to ensure good bonding, the firing temperature is preferably 600°C or higher, more preferably 650°C or higher, and even more preferably 700°C or higher. [Brief description of the drawings]

[0035] [Figure 1] FIG. 2 is a diagram showing the configuration of an electrochemical module. [Diagram 2] FIG. 2 is a diagram illustrating components constituting an electrochemical module. [Diagram 3] This is the result of measuring the electrical resistance. [Figure 4] This is the result of measuring the electrical resistance. [Diagram 5] This is an SEM image of the bonding material. [Figure 6] This is an SEM image of the bonding material. [Figure 7] FIG. 1 is a diagram showing the configuration of an energy system and an electrochemical device. [Figure 8] FIG. 1 is a diagram showing the configuration of an energy system and an electrochemical device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] The bonding material 10, the electrochemical module M, the electrochemical device Y, the solid oxide fuel cell, the energy system Z, and the method for manufacturing the electrochemical module M according to the embodiments of the present invention will be described below with reference to the drawings. Fig. 1 is a diagram showing the configuration of an electrochemical module M. Fig. 2 is a diagram explaining the members constituting the electrochemical module M. As shown in the figure, the electrochemical module M includes an alloy member 26, an electrochemical element E, and a bonding material 10 that bonds between the alloy member 26 and the electrochemical element E. In particular, the electrochemical module M shown in Fig. 1 includes a plurality of electrochemical elements E, and the plurality of electrochemical elements E are electrically connected to each other by the alloy member 26.

[0037] The electrochemical element E has a unit cell C configured by sandwiching an electrolyte layer 4 between an electrode layer 2 and a counter electrode layer 6. In this embodiment, the electrochemical element E has the unit cell C on a metal support (metal substrate) 1 having a through-hole 1a. The unit cell C of this embodiment has an electrode layer 2, an intermediate layer 3, an electrolyte layer 4, a reaction prevention layer (intermediate layer) 5, and a counter electrode layer 6.

[0038] The electrochemical element E is used, for example, as a component of a solid oxide fuel cell that generates electricity when supplied with a fuel gas containing hydrogen and air. When describing the positional relationship between layers, for example, the side of the counter electrode layer 6 as viewed from the electrolyte layer 4 may be referred to as the "top" or "upper side", and the side of the electrode layer 2 as the "bottom" or "lower side". In addition, the surface of the metal support 1 on which the electrode layer 2 is formed may be referred to as the front side, and the opposite surface may be referred to as the back side.

[0039] The electrochemical element E has a metal support 1, an electrode layer 2 formed on the metal support 1, an intermediate layer 3 formed on the electrode layer 2, an electrolyte layer 4 formed on the intermediate layer 3, a reaction prevention layer 5 formed on the electrolyte layer 4, and a counter electrode layer 6 formed on the reaction prevention layer 5. That is, the counter electrode layer 6 is formed on the electrolyte layer 4, and the reaction prevention layer 5 is formed between the electrolyte layer 4 and the counter electrode layer 6. For example, the electrode layer 2 is porous, and the electrolyte layer 4 is dense.

[0040] The metal support 1 supports the single cell C formed by sandwiching the electrolyte layer 4 between the electrode layer 2 and the counter electrode layer 6, thereby maintaining the strength of the electrochemical element E. In other words, the metal support 1 serves as a support for supporting the electrochemical element E.

[0041] As the material of the metal support 1, a material having excellent electronic conductivity, heat resistance, oxidation resistance, and corrosion resistance is used. For example, ferritic stainless steel, austenitic stainless steel, nickel-based alloy, etc. are used, but are not limited thereto. In particular, an alloy containing Cr is preferably used. In this embodiment, an Fe-Cr alloy containing 18 mass% or more and 25 mass% or less of Cr is used as the material of the metal support 1, but it is preferable to contain 0.05 mass% or more of Mn, and it is preferable to contain 0.05 mass% or more and 1.0 mass% or less of Ni. In addition, the lower limit of Cu is preferably 0.01 mass% or more, more preferably 0.10 mass% or more, and even more preferably 0.20 mass% or more, and the upper limit is preferably 1.0 mass% or less, more preferably 0.9 mass% or less, and even more preferably 0.8 mass% or less. The lower limit of Ti is preferably 0.05 mass% or more, more preferably 0.10 mass% or more, and even more preferably 0.15 mass% or more, and the upper limit is preferably 1.0 mass% or less, more preferably 0.9 mass% or less, and even more preferably 0.8 mass% or less. By using such an Fe-Cr alloy, an alloy member having excellent performance, durability, and corrosion resistance can be used as the metal support 1 while suppressing costs.

[0042] The metal support 1 is generally plate-shaped. The metal support 1 has a surface on which the electrode layer 2 is provided as a front surface and has a plurality of through holes 1a penetrating between the front surface and the back surface. The through holes 1a have a function of allowing gas to pass between the front side and the back side of the metal support 1. This allows the fuel gas and the oxidant gas to be smoothly supplied from the back surface of the metal support 1 to the electrode layer 2 side, thereby realizing a high-performance electrochemical element E. It is also possible to use the plate-shaped metal support 1 by bending it into a shape such as a box shape or a cylinder shape.

[0043] The electrode layer 2 can be provided as a thin layer on the surface of the metal support 1 so as to cover the through-holes 1a of the metal support 1. When the electrode layer 2 is a thin layer, the thickness can be, for example, about 1 μm to 100 μm, and preferably 5 μm to 50 μm. With such a thickness, it is possible to reduce the amount of expensive electrode layer 2 material used to cut costs while ensuring sufficient electrode performance.

[0044] Examples of materials for the electrode layer 2 include NiO-GDC, Ni-GDC, NiO-YSZ, Ni-YSZ, and CuO-CeO. 2 , Cu-CeO 2 Examples of such composites include GDC, YSZ, and CeO 2 These can be called aggregates of the composite material. The electrode layer 2 is preferably formed by a low-temperature firing method (for example, a wet method using a firing process in a low-temperature range that does not involve firing in a high-temperature range higher than 1100°C), a spray coating method (such as a thermal spray method, an aerosol deposition method, an aerosol gas deposition method, a powder jet deposition method, a particle jet deposition method, or a cold spray method), a PVD method (such as a sputtering method or a pulsed laser deposition method), or a CVD method.

[0045] The electrode layer 2 has a plurality of pores inside and on the surface to provide gas permeability. That is, the electrode layer 2 is formed as a porous layer. The electrode layer 2 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. The density is the ratio of the space occupied by the material constituting the layer, and can be expressed as (1-porosity), and is equivalent to the relative density.

[0046] The intermediate layer 3 can be formed in a thin layer state on the electrode layer 2. When the intermediate layer is a thin layer, the thickness can be, for example, about 1 μm to 100 μm, preferably about 2 μm to 50 μm, and more preferably about 4 μm to 25 μm. With such a thickness, it is possible to reduce the amount of expensive intermediate layer material used to reduce costs while ensuring sufficient performance. As the material for the intermediate layer 3, for example, YSZ (yttria-stabilized zirconia), SSZ (scandium-stabilized zirconia), GDC (gadolinium-doped ceria), YDC (yttrium-doped ceria), SDC (samarium-doped ceria), etc. can be used. In particular, ceria-based ceramics are preferably used.

[0047] The intermediate layer 3 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 (such as a thermal spray method, an aerosol deposition method, an aerosol gas deposition method, a powder jet deposition method, a particle jet deposition method, or a cold spray method), a PVD method (such as a sputtering method or a pulsed laser deposition method), or a CVD method. By using these film formation processes that can be used in a low-temperature range, the intermediate layer 3 can be obtained without firing in a high-temperature range higher than 1100°C, for example.

[0048] The intermediate layer 3 preferably has oxygen ion (oxide ion) conductivity. It is more preferable that the intermediate layer 3 has mixed conductivity of oxygen ions (oxide ions) and electrons. The intermediate layer 3 having these properties is suitable for application to the electrochemical element E.

[0049] The electrolyte layer 4 is formed in the state of a thin layer on the intermediate layer 3. Alternatively, it may be formed in the state of a thin film having a thickness of 10 μm or less.

[0050] The material of the electrolyte layer 4 may be YSZ (yttria-stabilized zirconia), SSZ (scandium-stabilized zirconia), GDC (gadolinium-doped ceria), YDC (yttrium-doped ceria), SDC (samarium-doped ceria), LSGM (strontium-magnesium-doped lanthanum gallate), LSO (lanthanum silicate, La 9.33+x S 6 O 26+2x / 3 ) or other electrolyte materials conducting oxygen ions, such as perovskite oxides, can be used. In particular, zirconia-based ceramics are preferably used. When the electrolyte layer 4 is made of zirconia-based ceramics, the operating temperature of the SOFC using the electrochemical element E can be made higher than that of ceria-based ceramics or various hydrogen ion conductive materials. For example, when the electrochemical element E is used in a SOFC, a material that can exhibit high electrolyte performance even in a high temperature range of about 650°C or higher, such as YSZ, is used as the material for the electrolyte layer 4, and 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 the anode gas of the SOFC by steam reforming or the like, thereby making it possible to construct a highly efficient SOFC system in which the heat generated in the cell stack of the SOFC is used to reform the raw fuel gas.

[0051] The electrolyte layer 4 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 method, etc. These film formation processes that can be used in a low-temperature range can provide an electrolyte layer 4 that is dense and has high airtightness and gas barrier properties without firing in a high-temperature range exceeding 1100°C, for example. In particular, the low-temperature firing method and the spray coating method are preferable because they can realize a low-cost element. Furthermore, the spray coating method is even more preferable because the electrolyte layer 4 that is dense and has high airtightness and gas barrier properties can be easily obtained in a low-temperature range.

[0052] The electrolyte layer 4 is densely configured to block gas leakage of the anode gas and the cathode gas and to exhibit high ion conductivity. The density of the electrolyte layer 4 is preferably 90% or more, more preferably 95% or more, and even more preferably 98% or more. When the electrolyte layer 4 is a uniform layer, the density is preferably 95% or more, and more preferably 98% or more. When the electrolyte layer 4 is configured in a multi-layered form, it is preferable that at least a part of the electrolyte layer 4 includes a layer (a dense electrolyte layer) having a density of 98% or more, and more preferably includes a layer (a dense electrolyte layer) having a density of 99% or more. When such a dense electrolyte layer is included in a part of the electrolyte layer 4, it is easy to form an electrolyte layer 4 that is dense and has high airtightness and gas barrier properties, even when the electrolyte layer 4 is configured in a multi-layered form.

[0053] The reaction prevention layer 5 can be formed in a thin layer state on the electrolyte layer 4. When the reaction prevention layer 5 is a thin layer, the thickness can be, for example, about 1 μm to 100 μm, preferably about 2 μm to 50 μm, and more preferably about 3 μm to 15 μm. With such a thickness, it is possible to reduce the amount of expensive reaction prevention layer material used to cut costs while ensuring sufficient performance.

[0054] The material of the reaction prevention layer 5 may be any material capable of preventing the reaction between the components of the electrolyte layer 4 and the components of the counter electrode layer 6, and may be, for example, a ceria-based material. The material of the reaction prevention layer 5 is preferably a material containing at least one element selected from the group consisting of Sm, Gd, and Y. The material preferably contains at least one element selected from the group consisting of Sm, Gd, and Y, and the total content of these elements is preferably 1.0 mass% or more and 10 mass% or less. By introducing the reaction prevention layer 5 between the electrolyte layer 4 and the counter electrode layer 6, the reaction between the constituent material of the counter electrode layer 6 and the constituent material of the electrolyte layer 4 can be effectively suppressed, and the long-term stability of the performance of the electrochemical element E can be improved. The reaction prevention layer 5 is preferably formed by a method capable of forming the layer at a processing temperature of 1100°C or less, since it can suppress damage to the metal support 1 and also suppress element diffusion between the metal support 1 and the electrode layer 2, thereby realizing an electrochemical element E having excellent performance and durability. For example, 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 method, etc. can be appropriately used. In particular, the low-temperature firing method and spray coating method are preferable because they allow low-cost elements to be realized. Furthermore, the low-temperature firing method is even more preferable because it makes it easier to handle the raw materials.

[0055] The counter electrode layer 6 can be formed in a thin layer state on the reaction prevention layer 5. When the reaction prevention layer 5 is not provided, the counter electrode layer 6 is formed on the electrolyte layer 4. When the counter electrode layer 6 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 6, 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 6 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 6 formed using the above materials functions as a cathode.

[0056] The counter electrode layer 6 is preferably formed by a method capable of forming the counter electrode layer 6 at a processing temperature of 1100° C. or less, since it is possible to suppress damage to the metal support 1 and also to suppress element diffusion between the metal support 1 and the electrode layer 2, thereby realizing an electrochemical element E having excellent performance and durability. For example, the counter electrode layer 6 can be formed by appropriately using a low-temperature firing method (for example, a wet method using a firing process in a low-temperature range without firing at a high temperature range exceeding 1100° C.), 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.

[0057] By configuring the electrochemical element E as described above, the electrochemical element E can be used as a power generation cell of a solid oxide fuel cell. For example, a fuel gas containing hydrogen is passed from the rear surface of the metal support 1 through the through holes 1a to the electrode layer 2, and air is passed to the counter electrode layer 6, which is the counter electrode of the electrode layer 2, and the electrochemical element E is operated at a temperature of, for example, 500°C to 900°C. Then, oxygen O contained in the air is absorbed in the counter electrode layer 6. 2 is electron e - reacts with oxygen ions O 2- The oxygen ion O 2- The hydrogen H contained in the supplied fuel gas moves through the electrolyte layer 4 to the electrode layer 2. 2 is oxygen ion O 2- Reacts with water H 2 O and electron e - When an electrolyte material that conducts hydrogen ions is used for the electrolyte layer 4, hydrogen H contained in the fuel gas flowing through the electrode layer 2 is generated. 2 is an electron e- releases hydrogen ions H + The hydrogen ion H + Oxygen O contained in the air moves through the electrolyte layer 4 to the counter electrode layer 6. 2 and hydrogen ion H + , electronic e - reacts to form water H 2 O is generated. The above reaction generates an electromotive force between the electrode layer 2 and the counter electrode layer 6. In this case, the electrode layer 2 functions as the fuel electrode (anode) of the SOFC, and the counter electrode layer 6 functions as the air electrode (cathode). In this manner, a solid oxide fuel cell is realized that includes the electrochemical module M and causes a power generation reaction in the single cell C.

[0058] Next, a method for manufacturing the electrochemical module M will be described.

[0059] In the electrode layer formation step, the electrode layer 2 is formed in a thin film state on the metal support 1. As described above, the electrode layer 2 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 (such as a thermal spray method, an aerosol deposition method, an aerosol gas deposition method, a powder jet deposition method, a particle jet deposition method, or a cold spray method), a PVD method (such as a sputtering method or a pulsed laser deposition method), or a CVD method. 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 metal support 1.

[0060] When the electrode layer formation step is performed by the low-temperature firing method, it is specifically performed as shown in the following example. First, a material powder of the electrode layer 2 is mixed with a solvent (dispersion medium) to prepare a material paste, which is then applied to the front surface of the metal support 1. The electrode layer 2 is then compression molded (electrode layer smoothing step), and fired at 1100°C or lower (electrode layer firing step). The electrode layer 2 can be compression molded by, for example, CIP (Cold Isostatic Pressing), roll pressing, RIP (Rubber Isostatic Pressing), or the like. The electrode layer 2 is preferably fired at a temperature of 800°C or higher and 1100°C or lower. The order of the electrode layer smoothing step and the electrode layer firing step can also be reversed. In the case of forming an electrochemical element E having an intermediate layer 3, the electrode layer smoothing step and the electrode layer firing step may be omitted, or the electrode layer smoothing step and the electrode layer firing step may be included in the intermediate layer smoothing step and the intermediate layer firing step described below. The electrode layer smoothing step may also be performed by carrying out lapping, leveling, cutting and polishing of the surface, or the like.

[0061] In the intermediate layer forming step, the intermediate layer 3 is formed in a thin layer state on the electrode layer 2 so as to cover the electrode layer 2. As described above, the intermediate layer 3 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 method at a temperature of 1100°C or less in order to suppress deterioration of the metal support 1.

[0062] When the intermediate layer forming step is performed by the low-temperature firing method, it is specifically performed as follows. First, the material powder of the intermediate layer 3 and a solvent (dispersion medium) are mixed to prepare a material paste, which is then applied to the front surface of the metal support 1. Then, the intermediate layer 3 is compression molded (intermediate layer smoothing step) and fired at 1100°C or less (intermediate layer firing step). The intermediate layer 3 can be rolled by, for example, CIP (Cold Isostatic Pressing), roll pressing, RIP (Rubber Isostatic Pressing), or the like. In addition, it is preferable to fire the intermediate layer 3 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 3 while suppressing damage and deterioration of the metal support 1. In addition, it is more preferable to fire the intermediate layer 3 at 1050°C or less, and even more preferable to fire it at 1000°C or less. This is because the lower the firing temperature of the intermediate layer 3, the more the electrochemical element E can be formed while suppressing damage and deterioration of the metal support 1. 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.

[0063] In the electrolyte layer forming step, the electrolyte layer 4 is formed in a thin layer state on the intermediate layer 3 while covering the electrode layer 2 and the intermediate layer 3. Alternatively, the electrolyte layer 4 may be formed in a thin film state having a thickness of 10 μm or less. As described above, the electrolyte layer 4 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 method at a temperature of 1100° C. or less in order to suppress deterioration of the metal support 1.

[0064] In order to form a high-quality electrolyte layer 4 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 of the electrolyte layer 4 is sprayed toward the intermediate layer 3 on the metal support 1 to form the electrolyte layer 4.

[0065] In the reaction prevention layer forming step, the reaction prevention layer 5 is formed in a thin layer state on the electrolyte layer 4. As described above, the reaction prevention layer 5 can be formed by a low-temperature firing method (a wet method in which firing is performed in a low temperature range of 1100°C or less), a spray coating method (a thermal spray method, an aerosol deposition method, an aerosol gas deposition method, a powder jet deposition method, a particle jet deposition method, a cold spray method, etc.), a PVD method (a sputtering method, a pulse laser deposition method, etc.), a CVD method, etc. In any case, it is preferable to perform the method at a temperature of 1100°C or less in order to suppress deterioration of the metal support 1. In order to flatten the upper surface of the reaction prevention layer 5, for example, a leveling treatment or a cutting / polishing treatment of the surface may be performed after the formation of the reaction prevention layer 5, or a press process may be performed after the wet formation and before firing.

[0066] In the counter electrode layer forming step, the counter electrode layer 6 is formed in a thin layer state on the reaction prevention layer 5. As described above, the counter electrode layer 6 can be formed by a low-temperature firing method (a wet method in which firing is performed in a low temperature range of 1100°C or less), a spray coating method (a thermal spray method, an aerosol deposition method, an aerosol gas deposition method, a powder jet deposition method, a particle jet deposition method, a cold spray method, or the like), a PVD method (a sputtering method, a pulsed laser deposition method, or the like), a CVD method, or the like. In any case, it is preferable to perform the method at a temperature of 1100°C or less in order to suppress deterioration of the metal support 1.

[0067] The electrochemical element E and the alloy member 26 produced as described above are sequentially joined in series using the joining material 10, thereby producing an electrochemical module M as shown in FIG. 1 and FIG. 2. Specifically, the counter electrode layer 6 of the electrochemical element E and the alloy member 26 are joined using the joining material 10. A U-shaped member 9 is joined to the back side of the metal support 1 of the electrochemical element E, and the alloy member 26 is joined to the U-shaped member 9. That is, the alloy member 26 is joined to the counter electrode layer 6 of the electrochemical element E and the U-shaped member 9, and electrically connects them. The metal support 1 and the U-shaped member 9 form a cylindrical support. Then, the gas flowing through the internal space of the cylindrical support is supplied to the electrode layer 2 through the through hole 1a of the metal support 1. In addition, from the viewpoint of reducing the thermal expansion difference with the metal support 1 and ensuring the reliability of the joining such as welding, the material of the U-shaped member 9 is preferably the same metal material as the metal support 1.

[0068] The alloy member 26 is a material containing Fe and Cr. For example, the alloy member 26 may be a ferritic stainless steel, an Fe-Cr-Ni alloy which is an austenitic stainless steel having superior heat resistance, or a nickel-based alloy. The material of the alloy member 26 is preferably the same as that of the metal support 1 from the viewpoint of reducing the difference in thermal expansion between the alloy member 26 and the metal support 1.

[0069] The manufacturing method of the electrochemical module M of this embodiment will be described. As shown in FIG. 1, each of the electrochemical elements E is stacked on the counter electrode layer 6 side facing the alloy member 26 via the bonding material 10, and on the metal support 1 side facing another alloy member 26 via a U-shaped member 9. As a part of the manufacturing method of the electrochemical module M, a bonding process is performed in which a material of the bonding material 10 is placed between the alloy member 26 and the electrochemical element E and sintered at a temperature less than 1000° C. For example, a bonding process is performed in which a paste containing fine particles of the bonding material 10 is placed between the alloy member 26 and the electrochemical element E and sintered. As a result, the alloy member 26 and the electrochemical element E can be bonded using the bonding material 10 for bonding them. The lower the sintering temperature in the bonding process, the more damage to the electrochemical module M can be reduced, so that it is more preferable that the sintering temperature is 900° C. or less, and even more preferable that the sintering temperature is 800° C. or less. In order to ensure good bonding, the sintering temperature is preferably 600° C. or more, more preferably 650° C. or more, and even more preferably 700° C. or more.

[0070] The bonding material 10 is preferably a material containing Co. Alternatively, the bonding material 10 is preferably a material containing Ni. Alternatively, the bonding material 10 is preferably a material containing a metal oxide containing at least two of Co, Mn, Cu, and Ni. Furthermore, the bonding material 10 has a structure in which a plurality of fine particles having an average particle size of 0.1 μm or more and 0.2 μm or less are assembled in a state in which the alloy member 26 and the single cell C of the electrochemical element E are bonded together. In addition, the bonding material 10 preferably has a porosity of 60% or more in a state in which the alloy member 26 and the single cell C of the electrochemical element E are bonded together. Furthermore, the porosity is more preferably 65% ​​or more. Furthermore, the thickness of the bonding material 10 is not particularly limited, but from the viewpoint of cost-effectiveness, it is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more, and is preferably 300 μm or less, more preferably 200 μm or less, and even more preferably 100 μm or less.

[0071] Next, the characteristics of the bonding material 10 will be described. FIG. 3 shows the results of measuring the electrical resistance between the counter electrode layer 6 and the alloy member 26 sandwiching the bonding material 10 for a sample in which the bonding material 10 was sintered (baked) at 700° C. and a sample in which the bonding material 10 was sintered (baked) at 850° C. in the bonding process. The material of the bonding material 10 is Co. 1.5 Mn 1.5 O 4 The electrical resistance was measured at 600°C to 900°C, which corresponds to the operating temperature range of a solid oxide fuel cell. As can be seen from Fig. 3, all of the samples showed low electrical resistance in the range of 600°C to 900°C.

[0072] FIG. 4 shows the results of measuring the electrical resistance when different materials are used for the bonding material 10. The samples are bonding materials 10 made of Co-Mn-O (Co 1.5 Mn 1.5 O 4 ), a sample using silver palladium (AgPd) paste as a comparative example, and a sample using LSCF (La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 The sintering temperature in the bonding process was 700° C., and the electrical resistance was measured at 750° C. As is clear from FIG. 4, the bonding material 10 was Co. 1.5 Mn 1.5 O 4 The sample of the embodiment using the bonding material 10 exhibited low electrical resistance from the start of the measurement, and the electrical resistance remained low even after 60 hours had passed. In contrast, the sample using the silver-palladium paste as the bonding material 10 exhibited high electrical resistance. 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 The sample using the above material exhibits a low electrical resistance at the start of the measurement, but the electrical resistance increases as time passes.

[0073] Next, Table 1 shows the results of comparing the characteristics of nine types of bonding materials 10. Samples 1 to 3 contain Co as the metal oxide constituting the bonding material 10. 1.5 Mn 1.5O 4 The bonding material 10 was fired (baked) at 700° C., 800° C., and 1000° C. in the bonding process. 2 MnO 4 The bonding material 10 was fired (baked) at 700° C., 800° C., and 1000° C. in the bonding process. 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 The bonding material 10 was fired (baked) at 700°C, 800°C, and 1000°C in the bonding process.

[0074] As can be seen from Table 1, increasing the firing temperature increases the average particle size and decreases the porosity.

[0075] [Table 1]

[0076] FIG. 5 is an SEM image showing the bonding surface (end surface) of the bonding material 10 of Sample 1 to Sample 9. FIG. 6 is an SEM image showing the cut surface of Sample 1 to Sample 9. The average particle size listed in Table 1 is a value calculated by software from the image shown in FIG. 5. The porosity listed in Table 1 is a value calculated by software from the image shown in FIG. 6. Specifically, the average particle size was calculated by reading the SEM image with ImageJ, binarizing the contrast (the threshold was automatically calculated and unified), dividing each particle with software, calculating the particle area in pixels, and taking the diameter of the circle corresponding to the particle area as the average particle size. Here, MakeBinary was used for binarization, Watershed was used for particle division, and AnalyzeParticle was used for particle area calculation within the ImageJ software analysis. The porosity was calculated by applying a median filter in ImageJ, extracting the void portion with Threshold, and automatically calculating the threshold. In other words, since the contrast is different between the void portion and the portion where the particle exists, the contrast difference was automatically calculated with the threshold.

[0077] As described above, the higher the sintering temperature of the bonding material 10 in the bonding process, the more the sintering of the bonding material 10 proceeds, the larger the average grain size, and the smaller the porosity. In other words, the higher the sintering temperature of the bonding material 10, the better the adhesion and the lower the contact resistance. In this embodiment, the sintering temperature of the bonding material 10 in the bonding process is set to less than 1000°C, thereby reducing damage to the electrochemical module M. In particular, considering the results of Figs. 3 and 4 together with the results of Table 1, if the material of the bonding material 10 is a Co-Mn spinel oxide and has an average grain size of 0.1 μm or more and 0.2 μm or less, good low resistance performance and high adhesion performance can be obtained while suppressing the sintering temperature of the bonding material 10 in the bonding process to a relatively low temperature of 700°C and 850°C. In addition, the Co corresponding to Samples 4 to 6 in Table 1 2 MnO 4 Although the results of measuring the electrical resistance are not shown, since the average particle size and porosity were similar to those of Samples 1 to 3, it is presumed that the material exhibits good low resistance and high adhesion properties.

[0078] FIG. 7 is a diagram showing the configuration of an energy system Z and an electrochemical device Y. The energy system Z has an electrochemical device Y and a heat exchanger 53 as a waste heat utilization section that reuses heat discharged from the electrochemical device Y. The electrochemical device Y at least has an electrochemical module M and a reformer 34 as a fuel converter that circulates a gas containing a reducing component to the electrochemical module M. In addition, the electrochemical device Y has an electrochemical module M and an inverter 38 as a power converter that extracts electric power from the electrochemical module M. The fuel supply module of the electrochemical device Y is composed of a desulfurizer 20, a vaporizer 33, a reformer 34, etc., and supplies a fuel gas containing a reducing component to the electrochemical module M.

[0079] In addition, the electrochemical device Y includes a reforming water tank 21, a blower 35, a combustion section 36, a control section 39, a storage container 40, a booster pump 41, a reforming water pump 43, and the like.

[0080] The vaporizer 33, the reformer 34, the electrochemical module M and the combustion section 36 are housed in a storage container 40. The reformer 34 uses combustion heat generated by the combustion of the reaction exhaust gas in the combustion section 36 to carry out a reforming process of the raw fuel.

[0081] The raw fuel is supplied to the desulfurizer 20 through a raw fuel supply passage 42 by the operation of a boost pump 41. The reforming water in the reforming water tank 21 is supplied to the vaporizer 33 through a reforming water supply passage 44 by the operation of a reforming water pump 43. The raw fuel supply passage 42 merges with the reforming water supply passage 44 at a location downstream of the desulfurizer 20, and the reforming water and raw fuel merged outside the storage container 40 are supplied to the vaporizer 33 provided inside the storage container 40.

[0082] The desulfurizer 20 removes (desulfurizes) sulfur compounds contained in hydrocarbon raw fuel such as city gas. When the raw fuel contains sulfur compounds, the provision of the desulfurizer 20 can suppress the effects of the sulfur compounds on the reformer 34 or the unit cells C of the electrochemical elements E that constitute the electrochemical module M. The vaporizer 33 generates water vapor from the reforming water supplied from the reforming water tank 21. The raw fuel containing the water vapor generated in the vaporizer 33 is supplied to the reformer 34 through a water vapor-containing raw fuel supply passage 45.

[0083] The reformer 34 uses the steam generated in the vaporizer 33 to steam reform the raw fuel desulfurized in the desulfurizer 20 to generate a reformed gas containing hydrogen. The reformed gas generated in the reformer 34 is supplied to the gas manifold 17 of the electrochemical module M through a reformed gas supply path 46.

[0084] The electrochemical elements E constituting the electrochemical module M are arranged in parallel while being electrically connected to each other, and one end (lower end) of the electrochemical elements E is fixed to the gas manifold 17. The reformed gas supplied to the gas manifold 17 is distributed to the electrochemical elements E. The electrochemical elements E constituting the electrochemical module M generate power by electrochemically reacting the reformed gas supplied from the reformer 34 with the air supplied from the blower 35. The reaction exhaust gas containing the remaining hydrogen gas not used in the reaction is discharged from the upper end of the electrochemical module M to the combustion section 36. The combustion section 36 mixes the reaction exhaust gas discharged from the electrochemical module M with air to combust the combustible components in the reaction exhaust gas.

[0085] The reaction exhaust gas combusted in the combustion section 36 becomes combustion exhaust gas and is discharged to the outside of the storage container 40 from the combustion exhaust gas outlet 50. A combustion catalyst section 51 (e.g., a platinum-based catalyst) is arranged in the combustion exhaust gas outlet 50, and burns and removes reducing components such as carbon monoxide and hydrogen contained in the combustion exhaust gas. The combustion exhaust gas discharged from the combustion exhaust gas outlet 50 is sent to a heat exchanger 53 through a combustion exhaust gas exhaust path 52.

[0086] The heat exchanger 53 exchanges heat between the combustion exhaust gas generated by the combustion in the combustion section 36 and the supplied cold water to generate hot water. In other words, the heat exchanger 53 operates as a waste heat utilization section that reuses the heat discharged from the electrochemical device Y.

[0087] Instead of the exhaust heat utilization section, a reaction exhaust gas utilization section may be provided that utilizes the reaction exhaust gas discharged (without being combusted) from the electrochemical module M. The reaction exhaust gas contains the remaining hydrogen gas that was not used in the reaction in the electrochemical element E that constitutes the electrochemical module M. In the reaction exhaust gas utilization section, the remaining hydrogen gas is utilized for heat utilization through combustion or for power generation using a fuel cell or the like, thereby making effective use of energy.

[0088] The inverter 38 adjusts the output power of the electrochemical module M to the same voltage and frequency as the power received from a commercial grid (not shown). The control unit 39 controls the operation of the electrochemical device Y and the energy system Z.

[0089] <Another embodiment> <1> In the above embodiment, an example of the structure of the electrochemical element E has been described, but the structure of the electrochemical element E can be appropriately modified. For example, the electrochemical element E may have a structure not including the metal support 1, that is, a structure in which the unit cell C is not supported by the metal support 1.

[0090] <2> In the above embodiment, an example was described in which the electrochemical module M is used in a solid oxide fuel cell, but the electrochemical module M can also be used in a solid oxide electrolysis cell, an oxygen sensor using a solid oxide, etc.

[0091] In the above embodiment, a configuration has been described that can improve the efficiency of converting chemical energy such as fuel into electrical energy. That is, in the above embodiment, the single cell C as the electrochemical element E constituting the electrochemical module M is operated as a fuel cell, hydrogen gas is circulated through the electrode layer 2, and oxygen gas is circulated through the counter electrode layer 6. Then, oxygen molecules O2 is electron e - reacts with oxygen ions O 2- The oxygen ion O 2- moves through the electrolyte layer 4 to the electrode layer 2. In the electrode layer 2, hydrogen molecules H 2 is oxygen ion O 2- Reacts with water H 2 O and electron e - The above reaction generates an electromotive force between the electrode layer 2 and the counter electrode layer 6, generating electricity.

[0092] A case will be described where a solid oxide electrolysis cell is realized that includes an electrochemical module M and generates an electrolytic reaction in a single cell C of an electrochemical element E. In the energy system Z shown in FIG. 8, when the electrochemical element E constituting the electrochemical module M is operated as an electrolysis cell, a gas containing water vapor and carbon dioxide is circulated through the electrode layer 2 serving as a fuel electrode, and a voltage is applied between the electrode layer 2 and the counter electrode layer 6 serving as an air electrode. Then, electrons e - and water molecule H 2 O, carbon dioxide molecule CO 2 reacts to produce hydrogen molecule H 2 Carbon monoxide (CO) and oxygen ions (O) 2- Oxygen ion O 2- The oxygen ions O move through the electrolyte layer 4 to the counter electrode layer 6. 2- releases electrons to form oxygen molecules O 2 Through the above reaction, water molecule H 2 O is hydrogen H 2 and oxygen O 2 And the carbon dioxide molecule CO 2 When gas containing carbon monoxide (CO) and oxygen (O) is circulated, 2 It is electrolyzed into

[0093] Water vapor and carbon dioxide molecule CO 2In the case where gas containing carbon monoxide is circulated, a fuel converter 91 can be provided that synthesizes various compounds such as hydrocarbons from the hydrogen and carbon monoxide produced in the electrochemical module M by the electrolysis. The hydrocarbons produced by the fuel converter 91 can be circulated to the electrochemical module M by a fuel supply unit (not shown), or can be taken out of the system / apparatus and used as a separate fuel or chemical raw material.

[0094] 8 , the electrochemical device Y at least includes an electrochemical module M and a fuel converter 91 that converts a gas containing a reducing component generated in the electrochemical module M. The electrochemical device Y also includes at least an electrochemical module M and a power converter 93 that supplies power to the electrochemical module M.

[0095] The electrochemical module M has a plurality of electrochemical elements E, a gas manifold 17, and a gas manifold 171. The electrochemical elements E are arranged in parallel while being electrically connected to each other, and one end (lower end) of the electrochemical elements E is fixed to the gas manifold 17, and the other end (upper end) is fixed to the gas manifold 171. The gas manifold 17 at one end (lower end) of the electrochemical elements E is supplied with water vapor and carbon dioxide. Hydrogen, carbon monoxide, and the like produced by the above-mentioned reaction in the electrochemical elements E are collected by the gas manifold 171, which communicates with the other end (upper end) of the electrochemical elements E.

[0096] Energy efficiency can be improved by configuring heat exchanger 90 in FIG. 8 to operate as a waste heat utilization section that exchanges heat between the reaction heat generated by the reaction in fuel converter 91 and water to vaporize them, and by configuring heat exchanger 92 in FIG. 8 to operate as a waste heat utilization section that exchanges heat between the waste heat generated by electrochemical element E and water vapor and carbon dioxide to preheat them. Furthermore, the power converter 93 supplies power to the unit cells C that constitute the electrochemical element E. This allows the electrochemical element E to function as an electrolysis cell as described above.

[0097] <3> In the above embodiment, examples of the material for the electrode layer 2 include NiO-GDC, Ni-GDC, NiO-YSZ, Ni-YSZ, and CuO-CeO. 2 , Cu-CeO 2 A composite material such as LSCF or LSM is used as the material for the counter electrode layer 6, and a composite oxide such as LSCF or LSM is used as the material for the counter electrode layer 6. The electrochemical element E configured in this manner can be used as a solid oxide fuel cell by supplying hydrogen gas to the electrode layer 2 to make it a fuel electrode (anode) and supplying air to the counter electrode layer 6 to make it an air electrode (cathode). It is also possible to change this configuration and configure the electrochemical element E so that the electrode layer 2 can be made an air electrode and the counter electrode layer 6 can be made a fuel electrode. That is, a composite oxide such as LSCF or LSM is used as the material for the electrode layer 2, and a composite oxide such as NiO-GDC, Ni-GDC, NiO-YSZ, Ni-YSZ, CuO-CeO is used as the material for the counter electrode layer 6. 2 , Cu-CeO 2 In the electrochemical element E configured in this manner, air is supplied to the electrode layer 2 to make it an air electrode, and hydrogen gas is supplied to the counter electrode layer 6 to make it a fuel electrode, so that the electrochemical element E can be used as a solid oxide fuel cell.

[0098] <4> In the above embodiment, the electrochemical element E may be configured to have either or both of the intermediate layer 3 (insertion layer) and the reaction prevention layer 5. That is, the electrode layer 2 and the electrolyte layer 4 may be formed in contact with each other, or the electrolyte layer 4 and the counter electrode layer 6 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.

[0099] <5> In the above embodiment, a flat plate type or cylindrical flat plate type solid oxide fuel cell is mainly used as the electrochemical element E, but the electrochemical element E may also be a cylindrical solid oxide fuel cell.

[0100] <6> In the above embodiment, the electrochemical device Y includes an electrochemical module M including a plurality of electrochemical elements E. However, the electrochemical device Y of the above embodiment can also be applied to a configuration including one electrochemical element E.

[0101] <7> In the above embodiment, the electrochemical element E has a configuration in which the U-shaped member 9 is attached to the back surface of the metal support 1, and the cylindrical support is formed by two members, the metal support 1 and the U-shaped member 9, but the cylindrical support may be formed by integrally forming the metal support 1 and the U-shaped member 9 using one member, or the cylindrical support may be formed by using three or more members. Also, the U-shaped member 9 may be omitted, and the electrode layer 2 and the like may be supported by the metal support 1.

[0102] <8> 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 merely examples, and the present invention is not limited to these embodiments. The present invention can be modified as appropriate within the scope of the present invention. [Industrial Applicability]

[0103] INDUSTRIAL APPLICABILITY The present invention can be used in a bonding material that ensures bonding performance even when baked at a low temperature, an electrochemical module, an electrochemical device, a solid oxide fuel cell, a solid oxide electrolysis cell, an energy system, and a method for manufacturing an electrochemical module. [Explanation of symbols]

[0104] 1: Metal support 2: Electrode layer 4: Electrolyte layer 5: Reaction prevention layer 6: Counter electrode layer 10: Bonding material 26: Alloy parts 91: Fuel converter 93: Power converter C: Single cell E: Electrochemical element M: Electrochemical module Y: Electrochemical device Z: Energy System

Claims

1. A bonding material for bonding an alloy member containing Fe and Cr to an electrochemical device having a single cell formed by sandwiching an electrolyte layer between an electrode layer and a counter electrode layer, The bonding material has a structure in which a plurality of fine particles having an average particle size of 0.1 μm or more and 0.2 μm or less are aggregated when the alloy member and the single cell are bonded together.

2. The bonding material according to claim 1 , further comprising Co.

3. The bonding material according to claim 1 or 2, which contains Ni.

4. The bonding material according to claim 1 , further comprising a metal oxide containing at least two of Co, Mn, Cu and Ni.

5. The bonding material according to any one of claims 1 to 4, wherein the alloy member and the electrochemical element have a porosity of 60% or more in a bonded state.

6. An electrochemical module comprising: the alloy member; the electrochemical element; and the bonding material according to any one of claims 1 to 5, which bonds the alloy member and the electrochemical element.

7. The electrochemical module according to claim 6 , comprising a plurality of the electrochemical elements, the plurality of the electrochemical elements being electrically connected to each other by the alloy member.

8. 8. The electrochemical module according to claim 6, wherein the electrochemical element comprises a reaction prevention layer between the electrolyte layer and the counter electrode layer.

9. 8. The electrochemical module according to claim 6, wherein the electrochemical device has a metal support for supporting the single cell.

10. 10. A solid oxide fuel cell comprising the electrochemical module according to claim 6, wherein a power generation reaction occurs in the unit cell.

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

12. An electrochemical device comprising at least the electrochemical module according to any one of claims 6 to 9, and a fuel converter that circulates a gas containing a reducing component through the electrochemical module, or a fuel converter that converts a gas containing a reducing component generated in the electrochemical module.

13. 10. An electrochemical device comprising at least the electrochemical module according to claim 6, and a power converter for extracting electric power from the electrochemical module or for supplying electric power to the electrochemical module.

14. 14. An energy system comprising: the electrochemical device according to claim 12 or 13; and a waste heat utilization section that reuses heat discharged from the electrochemical device.

15. A method for manufacturing an electrochemical module, comprising bonding an alloy member containing Fe and Cr to an electrochemical element having a single cell formed by sandwiching an electrolyte layer between an electrode layer and a counter electrode layer using the bonding material according to any one of claims 1 to 5, A method for manufacturing an electrochemical module, comprising a bonding step of disposing the bonding material between the alloy member and the electrochemical element and firing the material at a temperature of less than 1000°C.

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