JP2018174117A - Electrochemical element, electrochemical module, electrochemical device, energy system, solid oxide fuel cell, and manufacturing method of electrochemical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high performance electrochemical element and the like excellent in reliability and durability, which improves mass production cost while improving interlayer interface strength.SOLUTION: A reaction preventing layer 5 is formed to have a concavo-convex shape formed from a concave portion F and a convex portion G at an interface with an electrolyte layer 4. In the reaction preventing layer 5, a region on the side of the electrolyte layer 4 with respect to a line segment J connecting the bottom portions of two adjacent concave portions F via the convex portion G is defined as a protruding region K. In the reaction preventing layer 5, there is a sparse projecting region N which is the protruding region K in which the height at the top of the protruding region K from the line segment J is 0.5 μm or more and the porosity is larger than the porosity of an adjacent region L as a region on the side of the second electrode layer with respect to the line segment J defined as the adjacent region L.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an electrochemical element and a solid oxide fuel cell including the electrochemical element.

  Since solid oxide fuel cells operate at high temperatures, there is a known problem that delamination occurs due to stress generated due to the difference in thermal expansion coefficient between layers during a heat cycle. Therefore, in order to improve the strength against peeling in the prior art, it is disclosed that the strength against peeling is improved by adopting a two-layer structure in which an adhesion layer is inserted into the reaction preventing layer (Patent Document 1).

JP 2010-3478 A

  However, the prior art discloses a technique for realizing an SOFC suitable for operation at a relatively low temperature of about 600 ° C., and further improvement of the interlayer interface strength has been desired when operating at a higher temperature.

  The present invention has been made in view of the above-mentioned problems, and its purpose is to improve the interfacial strength while improving the cost at the time of mass production, a high-performance electrochemical device excellent in reliability and durability, etc. Is to provide.

[Configuration 1]
An electrochemical element having an electrolyte layer, an electrode layer, and a reaction preventing layer disposed between the electrolyte layer and the electrode layer,
The reaction preventing layer has a concavo-convex shape formed from a concave portion and a convex portion at the interface with the electrolyte layer,
In the reaction preventing layer, a region on the electrolyte layer side is defined as a protruding region with respect to a line segment connecting the bottoms of two adjacent concave portions via the convex portion, and the electrode layer side with respect to the line segment. Region as an adjacent region,
There is a sparse projecting region in which the height of the top of the projecting region from the line segment is 0.5 μm or more and the porosity is larger than the porosity of the adjacent region.

  As in the above feature configuration, if there is a sparse protruding region with a high porosity at the interface between the reaction preventing layer and the electrolyte layer, this sparse protruding region relieves stress caused by heat cycle, so the interface strength between layers improves. In addition, it is possible to provide an electrochemical element that is difficult to peel off.

[Configuration 2]
In the sparse protruding region, it is preferable that the distance between the bottoms of two concave portions adjacent to each other through the convex portion is 15 μm or less because stress can be sufficiently absorbed and relaxed.

[Configuration 3]
It is preferable that the porosity of the sparsely protruding region is 10% or more and 30% or less because stress can be sufficiently absorbed and relaxed. In addition, it is preferable that the porosity of the sparse protruding region is 13% or more because stress can be absorbed and relaxed. Moreover, since the intensity | strength of a reaction prevention layer can also be improved as the porosity of the said loose protrusion area | region is 26% or less, it is more preferable.

[Configuration 4]
When the porosity of the adjacent region is 1% or more and 20% or less, the strength of the reaction preventing layer can be secured, and the effect of preventing the components of the electrode layer from diffusing into the electrolyte layer is preferably increased. In addition, since the above-mentioned effect can be further improved when the porosity of the adjacent region is 15% or less, it is preferable. Further, it is more preferable that the porosity of the adjacent region is 2% or more because the stress relaxation effect is enhanced.

[Configuration 5]
It is preferable that the ratio of the porosity of the sparsely protruding region to the porosity of the adjacent region is 1.5 or more and 15 or less because both stress relaxation in the sparsely protruding region and securing of the strength of the reaction preventing layer can be achieved. Moreover, it is preferable that the ratio of the porosity of the sparsely protruding region to the porosity of the adjacent region is 2 or more and 10 or less because the effects of stress relaxation in the sparsely protruding region and ensuring the strength of the reaction preventing layer can be further enhanced.

[Configuration 6]
When the reaction preventing layer contains a material containing Ce, the ionic conductivity is high, and an increase in the resistance value of the reaction preventing layer can be suppressed, so that a high-performance electrochemical device can be realized.

[Configuration 7]
When the reaction preventing layer contains at least one element selected from the group consisting of Sm, Gd and Y, oxygen defects are introduced into the material constituting the reaction preventing layer, and the reaction preventing layer has a high ionic conductivity. This is preferable because a high-performance electrochemical device can be realized.

[Configuration 8]
When the reaction preventing layer contains at least one element selected from the group consisting of Sm, Gd and Y, and the total content of these elements is 5 mol% or more and 25 mol% or less, high ionic conductivity is obtained. can get. Moreover, since the higher ionic conductivity is obtained when the total content of elements selected from the group consisting of Sm, Gd and Y contained in the reaction prevention layer is 10 mol% or more and 20 mol% or less, it is more preferable.

[Configuration 9]
When the thickness of the reaction preventing layer is larger than 1 μm and not larger than 100 μm, it is preferable that the reaction preventing layer can sufficiently absorb and relax stress. Further, it is preferable that the thickness of the reaction preventing layer is larger than 2 μm because the reaction preventing layer can absorb and relax stress more. A thickness larger than 3 μm is preferable because the stress can be absorbed and relaxed further. Moreover, since the material cost of an expensive reaction prevention layer can be suppressed as the thickness of the said reaction prevention layer is 50 micrometers or less, it is preferable because the material cost can be further suppressed as 25 micrometers or less.

[Configuration 10]
The electrochemical element according to the present invention is characterized in that the electrode layer is a perovskite oxide containing two or more elements selected from the group consisting of La, Sr, Sm, Mn, Co and Fe. is there.

  According to said characteristic structure, since it can be set as the electrochemical element which has a high performance electrode layer, it is preferable.

[Configuration 11]
Another characteristic configuration of the electrochemical device according to the present invention is that the solid electrolyte layer contains zirconia ceramics.

  According to the above characteristic configuration, a solid electrolyte layer having high ionic conductivity and being thermodynamically stable at high temperature in an oxidizing / reducing atmosphere can be obtained. A chemical element can be obtained.

[Configuration 12]
Another characteristic configuration of the electrochemical device according to the present invention is that a counter electrode layer serving as a counter electrode of the electrode layer is provided on the reaction side and the side where the reaction preventing layer and the electrode layer of the solid electrolyte layer are disposed. It is in having.

  According to said characteristic structure, since the electrochemical element which has an electrode layer and a counter electrode layer can be formed, since it becomes easy to apply to a fuel cell etc., it is preferable.

[Configuration 13]
Another characteristic configuration of the electrochemical device according to the present invention is that it is supported by a metal support.

  According to the above characteristic configuration, the electrochemical element can be supported by an inexpensive and robust metal support, so that the amount of expensive ceramic material used can be reduced, and the strength is high and the reliability and durability are excellent. An electrochemical element can be obtained. Furthermore, since the processability is also excellent, the manufacturing cost can be reduced.

[Configuration 14]
The characteristic configuration of the electrochemical module according to the present invention is that it is arranged in a state where a plurality of the aforementioned electrochemical elements are assembled.

  According to the above characteristic configuration, a plurality of the above-described electrochemical elements are arranged in a collective state, so that the electrochemical module is excellent in strength and reliability while suppressing material cost and processing cost and being compact and high-performance. Can be obtained.

[Configuration 15]
A characteristic configuration of an electrochemical device according to the present invention includes at least the above-described electrochemical module and a reformer, and a fuel supply unit that supplies a fuel gas containing a reducing component to the electrochemical module. In the point.

  According to said characteristic structure, since it has a fuel supply part which has an electrochemical module and a reformer and supplies the fuel gas containing a reducing component with respect to an electrochemical module, existing raw fuels, such as city gas Using the supply infrastructure, it is possible to operate high-performance electrochemical modules with excellent durability and reliability. Moreover, since it becomes easy to construct a system for recycling unused fuel gas discharged from the electrochemical module, a highly efficient electrochemical device can be realized.

[Configuration 16]
The characteristic configuration of the electrochemical device according to the present invention is that it includes an inverter that extracts electric power from the electrochemical module.

  According to said characteristic structure, electric power can be taken out from an electrochemical module, and the electrochemical apparatus excellent in durability, reliability, and performance can be implement | achieved.

[Configuration 17]
The characteristic configuration of the energy system according to the present invention is that it includes the above-described electrochemical device and an exhaust heat utilization unit that reuses the heat exhausted from the electrochemical device.

  According to the above characteristic configuration, because it has an electrochemical device and a waste heat utilization part that reuses the heat exhausted from the electrochemical device, it is excellent in durability, reliability, and performance, and also in energy efficiency. An energy system can be realized. It is also possible to realize a hybrid system with excellent energy efficiency in combination with a power generation system that generates power using the combustion heat of unused fuel gas discharged from an electrochemical device.

[Configuration 18]
The characteristic configuration of the solid oxide fuel cell according to the present invention is that the counter electrode layer is a fuel electrode or an air electrode, and the electrode layer is an air electrode or a fuel electrode.

  According to the above characteristic configuration, a solid oxide fuel cell having a reaction prevention layer, a solid electrolyte layer, a fuel electrode, and an air electrode capable of absorbing and mitigating stress caused by expansion and contraction of a cell that occurs during heat cycle or power generation is realized. It is preferable because it is possible. If the solid oxide fuel cell can be operated in a temperature range of 650 ° C. or higher during rated operation, in the fuel cell system using hydrocarbon gas such as city gas as raw fuel, the raw fuel is converted to hydrogen. Since it is possible to construct a system that can cover the heat required for conversion with the exhaust heat of the fuel cell, the power generation efficiency of the fuel cell system can be increased, which is more preferable. Further, when the solid oxide fuel cell is operated at a temperature range of 900 ° C. or lower during rated operation, it is preferable to use a metal support because damage to the support can be suppressed. Further, it is more preferable to operate in a temperature range of 850 ° C. or lower during rated operation because damage to the support can be further suppressed.

[Configuration 19]
The electrochemical element manufacturing method according to the present invention includes a metal support, an electrolyte layer, an electrode layer, and an electrochemical reaction layer disposed between the electrolyte layer and the electrode layer. In the method for manufacturing an element, the reaction preventing layer is fired at 1100 ° C. or lower.

  According to the above characteristic configuration, the reaction prevention layer is baked at 1100 ° C. or lower, thereby having a porous and fine structure. For example, when used in a fuel cell, the cell expands and contracts during heat cycle or power generation. It is preferable because a reaction preventing layer that can absorb and relieve stress due to, and further can suppress separation from adjacent layers can be obtained. Further, it is more preferable that the reaction preventing layer is baked at a temperature of 1050 ° C. or lower because the above-described effect can be easily obtained. Furthermore, in order to suppress deterioration of the metal substrate 1, the reaction preventing layer is preferably baked at a temperature of 1100 ° C. or lower, more preferably 1050 ° C. or lower.

Schematic diagram showing the structure of the electrochemical device Schematic showing the configuration of the electrochemical element and electrochemical module Schematic showing the configuration of the electrochemical device and energy system Schematic diagram showing the structure of the electrochemical module Electron micrograph of cross section of electrochemical device

<First Embodiment>
Hereinafter, the electrochemical device E and the solid oxide fuel cell (Solid Oxide Fuel Cell: SOFC) according to the present embodiment will be described with reference to FIG. The electrochemical element E is used, for example, as a component of a solid oxide fuel cell that generates electric power by receiving supply of a fuel gas containing hydrogen and air. Hereinafter, when expressing the positional relationship of the layers, for example, the second electrode layer 6 side is “upper” or “upper side” and the first electrode layer 2 side is “lower” or “lower side” as viewed from the electrolyte layer 4. " Further, the surface of the metal substrate 1 on which the first electrode layer 2 is formed may be referred to as “front side”, and the opposite surface may be referred to as “back side”.

(Electrochemical element)
As shown in FIG. 1, the electrochemical element E includes a metal substrate 1 (metal support), a first electrode layer 2 (counter electrode layer) formed on the metal substrate 1, and a first electrode layer 2. It has an intermediate layer 3 formed thereon and an electrolyte layer 4 formed on the intermediate layer 3. The electrochemical element E further includes a reaction preventing layer 5 formed on the electrolyte layer 4 and a second electrode layer 6 (electrode layer) formed on the reaction preventing layer 5. That is, the second electrode layer 6 is formed on the electrolyte layer 4, and the reaction preventing layer 5 is formed between the electrolyte layer 4 and the second electrode layer 6. The electrochemical element E according to the present embodiment includes an electrolyte layer 4 and a reaction preventing layer 5 disposed between the electrolyte layer 4 and the second electrode layer. The first electrode layer 2 is porous, and the electrolyte layer 4 is dense.

(Metal substrate)
The metal substrate 1 serves as a support that supports the first electrode layer 2, the intermediate layer 3, the electrolyte layer 4, and the like and maintains the strength of the electrochemical element E. As the material of the metal substrate 1, a material excellent in electronic conductivity, heat resistance, oxidation resistance and corrosion resistance is used. For example, ferritic stainless steel, austenitic stainless steel, nickel base alloy, or the like is used. In particular, an alloy containing chromium is preferably used. In the present embodiment, the plate-shaped metal substrate 1 is used as the metal support, but the metal support may have other shapes such as a box shape or a cylindrical shape.
In addition, the metal substrate 1 should just have intensity | strength sufficient to form an electrochemical element as a support body, for example, about 0.1 mm-2 mm, Preferably it is about 0.1 mm-1 mm, More preferably, it is 0.00. A thickness of about 1 mm to 0.5 mm can be used.

  The metal substrate 1 has a plurality of through holes 1a provided through the front side surface and the back side surface. For example, the through-hole 1a can be provided in the metal substrate 1 by mechanical, chemical or optical drilling. The through hole 1a has a function of allowing gas to pass from the back surface of the metal substrate 1 to the front surface. In order to give the metal substrate 1 gas permeability, a porous metal can be used. For example, the metal substrate 1 can use a sintered metal, a foam metal, or the like.

A metal oxide layer 1 b as a diffusion suppression layer is provided on the surface of the metal substrate 1. That is, a diffusion suppression layer is formed between the metal substrate 1 and a first electrode layer 2 described later. The metal oxide layer 1b is provided not only on the surface exposed to the outside of the metal substrate 1, but also on the contact surface (interface) with the first electrode layer 2 and the inner surface of the through hole 1a. By this metal oxide layer 1b, element interdiffusion between the metal substrate 1 and the first electrode layer 2 can be suppressed. For example, when ferritic stainless steel containing chromium is used as the metal substrate 1, the metal oxide layer 1b is mainly chromium oxide. And the metal oxide layer 1b which has chromium oxide as a main component suppresses that the chromium atom etc. of the metal substrate 1 diffuse to the 1st electrode layer 2 or the electrolyte layer 4. FIG. The thickness of the metal oxide layer 1b may be a thickness that can achieve both high diffusion prevention performance and low electrical resistance. For example, it is preferably in the submicron order, and specifically, the average thickness is more preferably about 0.3 μm or more and 0.7 μm or less. Further, the minimum thickness is more preferably about 0.1 μm or more.
The maximum thickness is preferably about 1.1 μm or less.
Although the metal oxide layer 1b can be formed by various methods, a method of oxidizing the surface of the metal substrate 1 to form a metal oxide is preferably used. Further, a metal oxide layer 1b is applied to the surface of the metal substrate 1 by a spray coating method (spraying method, aerosol deposition method, aerosol gas deposition method, powder jet deposition method, particle jet deposition method, cold spray method, etc. Method), PVD method such as sputtering method or PLD method, CVD method or the like, or plating and oxidation treatment. Further, the metal oxide layer 1b may include a spinel phase having high conductivity.

  When a ferritic stainless steel is used as the metal substrate 1, YSZ (yttria-stabilized zirconia) or GDC (also referred to as gadolinium doped ceria, CGO) used as the material for the first electrode layer 2 or the electrolyte layer 4 and heat The expansion coefficient is close. Therefore, even when the temperature cycle of low temperature and high temperature is repeated, the electrochemical element E is not easily damaged. Therefore, it is preferable because an electrochemical element E having excellent long-term durability can be realized.

(First electrode layer)
As shown in FIG. 1, the first electrode layer 2 can be provided in a thin layer state on a surface on the front side of the metal substrate 1 and larger than the region where the through hole 1 a is provided. In the case of 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 and reducing costs. The entire region where the through hole 1 a is provided is covered with the first electrode layer 2. That is, the through hole 1a is formed inside the region of the metal substrate 1 where the first electrode layer 2 is formed. In other words, all the through holes 1 a are provided facing the first electrode layer 2.

As the first electrode layer 2 material can be used, for example NiO-GDC, Ni-GDC, NiO-YSZ, Ni-YSZ, a composite material such as _{CuO-CeO 2, Cu-CeO} 2. In these examples, GDC, YSZ, and CeO ₂ can be referred to as composite aggregates. The first electrode layer 2 may be formed by a low temperature baking method (for example, a wet method using a baking process in a low temperature range that does not perform a baking process in a high temperature range higher than 1100 ° C.) or a spray coating method (a thermal spraying method or an aerosol deposition method, It is preferably formed by 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 (such as a sputtering method or a pulse laser deposition method), a CVD method or the like. By these processes that can be used in a low temperature range, a good first electrode layer 2 can be obtained without using firing in a high temperature range higher than 1100 ° C., for example. Therefore, it is preferable because the interdiffusion of elements between the metal substrate 1 and the first electrode layer 2 can be suppressed without damaging the metal substrate 1 and an electrochemical element having excellent durability can be realized. Furthermore, it is more preferable to use a low-temperature firing method because handling of raw materials becomes easy.

The first electrode layer 2 has a plurality of pores inside and on the surface in order to provide gas permeability.
That is, the first electrode layer 2 is formed as a porous layer. For example, the first electrode layer 2 is formed so that the density thereof is 30% or more and less than 80%. As the size of the pores, a size suitable for a smooth reaction to proceed during the electrochemical reaction can be appropriately selected. The dense 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.

(Middle layer)
As shown in FIG. 1, the intermediate layer 3 can be formed in a thin layer on the first electrode layer 2 while covering the first electrode layer 2. In the case of 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 ensure sufficient performance while reducing the cost by reducing the amount of expensive intermediate layer material used. Examples of the material of the intermediate layer 3 include YSZ (yttria-stabilized zirconia), SSZ (scandium-stabilized zirconia), GDC (gadolinium-doped ceria), YDC (yttrium-doped ceria), and SDC (samarium-doped ceria). Ceria) or the like can be used. In particular, ceria-based ceramics are preferably used.

The intermediate layer 3 is formed by a low-temperature baking method (for example, a wet method using a baking process in a low temperature range that does not perform a baking process in a high temperature range higher than 1100 ° C.) or a spray coating method (a thermal spraying method, an aerosol deposition method, an aerosol gas deposition). It is preferably formed by a method such as a method such as a powder jet deposition method, a particle jet deposition method, or a cold spray method), a PVD method (such as a sputtering method or a pulse laser deposition method), or a CVD method. By these film forming processes that can be used in a low temperature region, the intermediate layer 3 can be obtained without firing in a high temperature region higher than 1100 ° C., for example. Therefore, elemental interdiffusion between the metal substrate 1 and the first electrode layer 2 can be suppressed without damaging the metal substrate 1, and an electrochemical element E having excellent durability can be realized.
Further, it is more preferable to use a low-temperature baking method because handling of raw materials becomes easy.

  The intermediate layer 3 preferably has oxygen ion (oxide ion) conductivity. Further, it is more preferable to have 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.

(Electrolyte layer)
As shown in FIG. 1, the electrolyte layer 4 is formed in a thin layer on the intermediate layer 3 while covering the first electrode layer 2 and the intermediate layer 3. Moreover, it can also form in the state of a thin film whose thickness is 10 micrometers or less. Specifically, as shown in FIG. 1, the electrolyte layer 4 is provided over (over straddling) the intermediate layer 3 and the metal substrate 1. By comprising in this way and joining the electrolyte layer 4 to the metal substrate 1, the whole electrochemical element can be excellent in robustness.

  In addition, as shown in FIG. 1, the electrolyte layer 4 is provided in a region on the front side surface of the metal substrate 1 that is larger than the region in which the through hole 1a is provided. That is, the through hole 1a is formed inside the region of the metal substrate 1 where the electrolyte layer 4 is formed.

  Further, gas leakage from the first electrode layer 2 and the intermediate layer 3 can be suppressed around the electrolyte layer 4. To explain, when the electrochemical element E is used as a component of SOFC, gas is supplied from the back side of the metal substrate 1 to the first electrode layer 2 through the through hole 1a when the SOFC is operated. In a portion where the electrolyte layer 4 is in contact with the metal substrate 1, gas leakage can be suppressed without providing another member such as a gasket. In the present embodiment, the entire periphery of the first electrode layer 2 is covered with the electrolyte layer 4. However, the electrolyte layer 4 is provided above the first electrode layer 2 and the intermediate layer 3, and a gasket or the like is provided around the electrolyte layer 4. Also good.

  Examples of the material of the electrolyte layer 4 include YSZ (yttria stabilized zirconia), SSZ (scandium stabilized zirconia), GDC (gadolinium doped ceria), YDC (yttrium doped ceria), SDC (samarium doped ceria). LSGM (strontium / magnesium-added lanthanum gallate) or the like can be used. In particular, zirconia ceramics are preferably used. When the electrolyte layer 4 is made of zirconia ceramics, the operating temperature of the SOFC using the electrochemical element E can be made higher than that of ceria ceramics. For example, when the electrochemical element E is used for SOFC, the material of the electrolyte layer 4 is made of a material that can exhibit high electrolyte performance even in a high temperature range of about 650 ° C. or higher, such as YSZ. Using a hydrocarbon-based raw fuel and a system configuration in which the raw fuel is made into SOFC anode gas by steam reforming, etc., a highly efficient SOFC system that uses heat generated in the SOFC cell stack for raw fuel gas reforming Can be built.

  The electrolyte layer 4 is formed by a low temperature baking method (for example, a wet method using a baking process in a low temperature range in which a baking process is not performed in a high temperature range exceeding 1100 ° C.) or a spray coating method (a thermal spraying method, an aerosol deposition method, an aerosol gas deposition). It is preferably formed by a method such as a method such as a powder jet deposition method, a particle jet deposition method, or a cold spray method), a PVD method (such as a sputtering method or a pulse laser deposition method), or a CVD method. By these film forming processes that can be used in a low temperature region, the electrolyte layer 4 having a high density and a high gas barrier property can be obtained without firing in a high temperature region exceeding 1100 ° C., for example. Therefore, damage to the metal substrate 1 can be suppressed, elemental interdiffusion between the metal substrate 1 and the first electrode layer 2 can be suppressed, and an electrochemical element E excellent in performance and durability can be realized. In particular, it is preferable to use a low-temperature firing method or a spray coating method because a low-cost element can be realized. Furthermore, it is more preferable to use a spray coating method because a dense electrolyte layer having a high gas tightness and gas barrier property can be easily obtained in a low temperature range.

  The electrolyte layer 4 is densely configured to shield gas leakage of the anode gas and the cathode gas and to exhibit high ionic conductivity. The density of the electrolyte layer 4 is preferably 90% or more, more preferably 95% or more, and further 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. In the case where the electrolyte layer 4 is configured in a plurality of layers, it is preferable that at least a part thereof includes a layer (dense electrolyte layer) having a density of 98% or more, and 99% It is more preferable that the above layer (dense electrolyte layer) is included. When such a dense electrolyte layer is included in a part of the electrolyte layer, even if the electrolyte layer is formed in a plurality of layers, a dense electrolyte layer having high gas tightness and gas barrier properties is formed. This is because it can be easily done.

(Anti-reaction layer)
The reaction preventing layer 5 can be formed on the electrolyte layer 4 in a thin layer state. In the case of a thin layer, it is preferable that the thickness is greater than 1 μm and not greater than 100 μm because the reaction preventing layer can sufficiently absorb and relax stress. Further, it is preferable that the thickness of the reaction preventing layer is larger than 2 μm because the reaction preventing layer can absorb and relax stress more. A thickness larger than 3 μm is preferable because the stress can be absorbed and relaxed further. Moreover, since the material cost of an expensive reaction prevention layer can be suppressed as the thickness of the said reaction prevention layer is 50 micrometers or less, it is preferable because the material cost can be further suppressed as 25 micrometers or less.

  As the material of the reaction preventing layer 5, a material that can prevent a reaction between the component of the electrolyte layer 4 and the component of the second electrode layer 6 is used. By introducing the reaction preventing layer 5 between the electrolyte layer 4 and the second electrode layer 6, the reaction between the constituent material of the second electrode layer 6 and the constituent material of the electrolyte layer 4 is effectively suppressed, and electrochemical The long-term stability of the performance of the element E can be improved.

  In the present embodiment, a material containing Ce is used as the material of the reaction preventing layer 5. As the material for the reaction preventing layer 5, a material containing at least one element selected from the group consisting of Sm, Gd and Y is preferably used. The formed reaction prevention layer 5 contains at least one element selected from the group consisting of Sm, Gd and Y, and the total content of these elements is 5 mol% or more and 25 mol% or less. It is preferable because high ionic conductivity can be obtained. Moreover, since the higher ionic conductivity is obtained when the total content of elements selected from the group consisting of Sm, Gd and Y contained in the reaction prevention layer is 10 mol% or more and 20 mol% or less, it is more preferable. Specifically, as the material of the reaction preventing layer 5, GDC (gadolinium-doped ceria), YDC (yttrium-doped ceria), SDC (samarium-doped ceria), or the like can be used.

  When the reaction preventing layer 5 is formed by appropriately using a method that can be formed at a processing temperature of 1100 ° C. or less, damage to the metal substrate 1 is suppressed, and element interdiffusion between the metal substrate 1 and the first electrode layer 2 is suppressed. Can be suppressed, and an electrochemical element E excellent in performance and durability can be realized. For example, low-temperature firing methods (for example, wet methods using a firing treatment in a low temperature range that does not perform a firing treatment in a high temperature range exceeding 1100 ° C.), spray coating methods (thermal spraying method, aerosol deposition method, aerosol gas deposition method, powder) A 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 can be used as appropriate. In particular, it is preferable to use a low-temperature firing method or a spray coating method because a low-cost element can be realized. Furthermore, it is more preferable to use a low-temperature firing method because handling of raw materials becomes easy.

  In this embodiment, the reaction preventing layer 5 is formed with two regions of a porous and fine structure and a dense structure.

  Hereinafter, the characteristic uneven | corrugated shape which the electrolyte layer 4 of this embodiment has is demonstrated, referring FIG. FIG. 5 is an electron micrograph of a cross section of the electrochemical element E according to the present embodiment. In FIG. 5, the pore space inside the reaction preventing layer 5 is shown in black.

  The reaction preventing layer 5 is formed to have a concavo-convex shape formed from the concave portion F and the convex portion G at the interface with the electrolyte layer 4. In the reaction preventing layer 5, a region on the electrolyte layer 4 side is defined as a protruding region K with respect to a line segment J connecting the bottoms of two concave portions F adjacent to each other via the convex portion G. In the reaction preventing layer 5, the region on the second electrode layer 6 side with respect to the line segment J is set as the adjacent area L, and the height from the line segment J at the top of the protruding area K is 0.5 μm or more, and There is a sparse protruding region N which is a protruding region K whose porosity is larger than the porosity of the adjacent region L. In the sparsely projecting region N, the distance between the bottoms of the two concave portions F adjacent via the convex portion G is 15 μm or less.

  In the electron micrograph of FIG. 5, the first electrode layer 2, the electrolyte layer 4, and the reaction preventing layer 5 are shown. The interface between the reaction preventing layer 5 and the electrolyte layer 4 is located extending in the left-right direction near the center of the visual field in the vertical direction. A concave portion F1, a convex portion G1, a concave portion F2, a convex portion G2, and a concave portion F3 are formed on the interface in order from the left of the field of view.

  The line segment J1 is a line segment connecting the bottoms of the two recesses F1 and the recesses F2. A region on the side of the electrolyte layer 4 with respect to the line segment J1 is defined as a protruding region K1. A region on the second electrode layer 6 side with respect to the line segment J1 is defined as an adjacent region L1. The height from the line segment J1 at the top of the protruding region K1 is 1.39 μm, which is 0.5 μm or more. And as FIG. 5 shows, there exists more pore space in the protrusion area | region K1 compared with the adjacent area | region L1. Accordingly, the protruding region K1 has a porosity higher than that of the adjacent region L1. Therefore, the protruding region K1 corresponds to the sparse protruding region N.

  In the protruding region K1, which is the sparse protruding region N, the distance between the bottoms of the two concave portions F1 and the concave portions F2 adjacent to each other via the convex portion G1 is 10.5 μm, and is 15 μm or less.

  The line segment J2 is a line segment connecting the bottoms of the two recesses F2 and the recess F3. A region on the side of the electrolyte layer 4 with respect to the line segment J2 is defined as a protruding region K2. A region on the second electrode layer 6 side with respect to the line segment J2 is defined as an adjacent region L2. The height from the line segment J2 at the top of the protruding region K2 is 1.63 μm, which is 0.5 μm or more. And as FIG. 5 shows, more pore space exists in the protrusion area | region K2 compared with the adjacent area | region L2. Accordingly, the protruding region K2 has a porosity higher than that of the adjacent region L2. Therefore, the protruding region K2 corresponds to the sparse protruding region N.

  In the protruding region K2, which is the sparse protruding region N, the distance between the bottoms of the two recessed portions F2 and the recessed portion F3 adjacent to each other via the protruding portion G2 is 10.3 μm, and is 15 μm or less.

  In the present embodiment, the reaction preventing layer 5 is formed so that the porosity of the sparsely protruding region N is 10% or more and 30% or less, and the porosity of the adjacent region L is 1% or more and 15% or less. In particular, it is preferable that the ratio of the porosity of the sparsely projecting region N to the porosity of the adjacent region L is 1.5 or more and 15 or less.

(Second electrode layer)
The second electrode layer 6 can be formed in a thin layer on the reaction preventing layer 5. In the case of 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 cost by reducing the amount of expensive second electrode layer material used. As the material of the second electrode layer 6, for example, composite oxides such as LSCF and LSM, ceria-based oxides, and mixtures thereof can be used. In particular, the second electrode layer 6 preferably contains a perovskite oxide containing two or more elements selected from the group consisting of La, Sr, Sm, Mn, Co, and Fe. The 2nd electrode layer 6 comprised using the above material functions as a cathode.

  In addition, when the formation of the second electrode layer 6 is appropriately performed using a method that can be formed at a processing temperature of 1100 ° C. or less, damage to the metal substrate 1 is suppressed, and the metal substrate 1 and the first electrode layer 2 are not damaged. Elemental interdiffusion can be suppressed, and an electrochemical element E excellent in performance and durability can be realized, which is preferable. For example, low-temperature firing methods (for example, wet methods using a firing treatment in a low temperature range that does not perform a firing treatment in a high temperature range exceeding 1100 ° C.), spray coating methods (thermal spraying method, aerosol deposition method, aerosol gas deposition method, powder) A 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 can be used as appropriate. In particular, it is preferable to use a low-temperature firing method or a spray coating method because a low-cost element can be realized. Furthermore, it is more preferable to use a low-temperature firing method because handling of raw materials becomes easy.

(Solid oxide fuel cell)
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 supplied from the back surface of the metal substrate 1 to the first electrode layer 2 through the through-hole 1a, and air is supplied to the second electrode layer 6 that is the counter electrode of the first electrode layer 2. , And operate at a temperature of 500 ° C. or higher and 900 ° C. or lower. Then, oxygen O ₂ contained in air reacts with electrons e ⁻ in the second electrode layer 6 to generate oxygen ions O ²⁻ . The oxygen ions O ²⁻ move through the electrolyte layer 4 to the first electrode layer 2. In the first electrode layer 2, hydrogen H ₂ contained in the supplied fuel gas reacts with oxygen ions O ²⁻ to generate water H ₂ O and electrons e ⁻ . Due to the above reaction, an electromotive force is generated between the first electrode layer 2 and the second electrode layer 6. In this case, the first electrode layer 2 functions as an SOFC fuel electrode (anode), and the second electrode layer 6 functions as an air electrode (cathode).

(Method for producing electrochemical element)
Next, the manufacturing method of the electrochemical element E which concerns on this embodiment is demonstrated.

(First electrode layer forming step)
In the first electrode layer forming step, the first electrode layer 2 is formed as a thin film in a region wider than the region where the through hole 1a on the front side surface of the metal substrate 1 is provided. The through hole of the metal substrate 1 can be provided by laser processing or the like. As described above, the first electrode layer 2 is formed by a low-temperature baking method (wet method in which baking is performed in a low temperature region of 1100 ° C. or lower), a spray coating method (thermal spraying method, aerosol deposition method, aerosol gas deposition). For example, a method such as a powder jet deposition method, a particle jet deposition method, or a cold spray method), a PVD method (such as a sputtering method or a pulse laser deposition method), or a CVD method. Regardless of which method is used, it is desirable to carry out at a temperature of 1100 ° C. or lower in order to suppress the deterioration of the metal substrate 1.

When the first electrode layer forming step is performed by a low temperature firing method, specifically, it is performed as in the following example.
First, the material powder of the 1st electrode layer 2 and a solvent (dispersion medium) are mixed, a material paste is created, and it applies to the surface of the metal substrate 1 at the front side. And the 1st electrode layer 2 is compression-molded (electrode layer smoothing process), and it bakes at 1100 degrees C or less (electrode layer baking process). The compression molding of the first electrode layer 2 can be performed by, for example, CIP (Cold Isostatic Pressing) molding, roll press molding, RIP (Rubber Isostatic Pressing) molding, or the like. The electrode layer is preferably fired at a temperature of 800 ° C. or higher and 1100 ° C. or lower. Further, the order of the electrode layer smoothing step and the electrode layer firing step can be interchanged.
In the case of forming an electrochemical device having an intermediate layer, the electrode layer smoothing step and the electrode layer firing step are omitted, or the electrode layer smoothing step and the electrode layer firing step are described later. It can also be included in the firing step.
The electrode layer smoothing step may be performed by lapping, leveling, surface cutting / polishing, or the like.

(Diffusion suppression layer formation step)
During the firing step in the first electrode layer forming step described above, the metal oxide layer 1b (diffusion suppression layer) is formed on the surface of the metal substrate 1. If the firing step includes a firing step in which the firing atmosphere is an atmospheric condition with a low oxygen partial pressure, a high-quality metal oxide layer 1b (diffusion restraint) that has a high element interdiffusion suppression effect and a low resistance value. Layer) is preferable. A separate diffusion suppression layer forming step may be included, including the case where the first electrode layer forming step is a coating method in which baking is not performed. In any case, it is desirable to carry out at a processing temperature of 1100 ° C. or less that can suppress damage to the metal substrate 1. Moreover, the metal oxide layer 1b (diffusion suppression layer) may be formed on the surface of the metal substrate 1 during the firing step in the intermediate layer forming step described later.

(Intermediate layer forming step)
In the intermediate layer forming step, the intermediate layer 3 is formed in a thin layer on the first electrode layer 2 so as to cover the first electrode layer 2. As described above, the intermediate layer 3 is formed by a low-temperature baking method (wet method in which baking is performed in a low temperature region of 1100 ° C. or lower), a spray coating method (a thermal spraying method, an aerosol deposition method, an aerosol gas deposition method, A method such as a powder jet deposition method, a particle jet deposition method, or a cold spray method), a PVD method (such as a sputtering method or a pulse laser deposition method), or a CVD method can be used. Regardless of which method is used, it is desirable to carry out at a temperature of 1100 ° C. or lower in order to suppress the deterioration of the metal substrate 1.

When the intermediate layer forming step is performed by a low-temperature firing method, specifically, it is performed as in the following example.
First, the material powder of the intermediate layer 3 and a solvent (dispersion medium) are mixed to prepare a material paste, which is applied to the front surface of the metal substrate 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 rolling of the intermediate layer 3 can be performed by, for example, CIP (Cold Isostatic Pressing) molding, roll pressing molding, RIP (Rubber Isostatic Pressing) molding, or the like. The intermediate layer is preferably fired at a temperature of 800 ° C. or higher and 1100 ° C. or lower. This is because the intermediate layer 3 having a high strength can be formed while suppressing damage and deterioration of the metal substrate 1 at such a temperature. Moreover, it is more preferable when baking of the intermediate | middle layer 3 is performed at 1050 degrees C or less, and it is still more preferable when it is performed at 1000 degrees C or less. This is because the electrochemical element E can be formed while further suppressing the damage and deterioration of the metal substrate 1 as the firing temperature of the intermediate layer 3 is lowered. Further, the order of the intermediate layer smoothing step and the intermediate layer firing step can be switched.
The intermediate layer smoothing step may be performed by lapping, leveling, surface cutting / polishing, or the like.

(Electrolyte layer forming step)
In the electrolyte layer forming step, the electrolyte layer 4 is formed in a thin layer on the intermediate layer 3 while covering the first electrode layer 2 and the intermediate layer 3. Moreover, you may form in the state of a thin film whose thickness is 10 micrometers or less. As described above, the electrolyte layer 4 is formed by a low temperature firing method (wet method in which a firing process is performed at a low temperature of 1100 ° C. or lower), a spray coating method (a thermal spraying method, an aerosol deposition method, an aerosol gas deposition method, A method such as a powder jet deposition method, a particle jet deposition method, or a cold spray method), a PVD method (such as a sputtering method or a pulse laser deposition method), or a CVD method can be used. Regardless of which method is used, it is desirable to carry out at a temperature of 1100 ° C. or lower in order to suppress the deterioration of the metal substrate 1.

  In order to form a high-quality electrolyte layer 4 that is dense and airtight and has high gas barrier performance in a temperature range of 1100 ° C. or lower, it is desirable to perform the electrolyte layer formation step by spray coating. In that case, the material of the electrolyte layer 4 is sprayed toward the intermediate layer 3 on the metal substrate 1 to form the electrolyte layer 4.

(Reaction prevention layer formation step)
In the reaction preventing layer forming step, the reaction preventing layer 5 is formed on the electrolyte layer 4 in a thin layer state. As described above, the reaction preventing layer 5 is formed by a low-temperature baking method, a spray coating method (a thermal spraying 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.), PVD method (sputtering method, pulsed laser deposition method, etc.), CVD method and the like can be used. Whichever method is used, in order to suppress deterioration of the metal substrate 1, it is preferably performed at a temperature of 1100 ° C. or lower, more preferably 1050 ° C. or lower. In order to flatten the upper surface of the reaction preventing layer 5, for example, a leveling process or a surface cutting / polishing process may be performed after the formation of the reaction preventing layer 5, or a press working may be performed after the wet formation and before firing. Good.

(Second electrode layer forming step)
In the second electrode layer forming step, the second electrode layer 6 is formed in a thin layer on the reaction preventing layer 5. As described above, the second electrode layer 6 is formed by a low temperature baking method, a spray coating method (a thermal spraying method, an aerosol deposition method, an aerosol gas deposition method, a powder jet deposition method, a particle jet deposition method, a cold spray). And other methods), PVD methods (sputtering methods, pulsed laser deposition methods, etc.), CVD methods, and the like can be used. Regardless of which method is used, it is desirable to carry out at a temperature of 1100 ° C. or lower in order to suppress the deterioration of the metal substrate 1.

  The electrochemical element E can be manufactured as described above. In addition, the board | substrate B with an electrode layer for metal support type | mold electrochemical elements can be manufactured by performing the 1st electrode layer formation step and intermediate | middle layer formation step which were described above. That is, the manufacturing method according to the present embodiment includes a metal substrate 1 (metal support), a first electrode layer 2 formed on the metal substrate 1, and an intermediate layer 3 formed on the first electrode layer 2. A method for producing a substrate B with an electrode layer for a metal-supported electrochemical device, comprising an intermediate layer smoothing step of smoothing the surface of the intermediate layer 3, and firing the intermediate layer 3 at 1100 ° C. or less Including an intermediate layer firing step.

  Note that the electrochemical element E may be configured without the intermediate layer 3. That is, a form in which the first electrode layer 2 and the electrolyte layer 4 are formed in contact with each other is also possible. In this case, the intermediate layer forming step is omitted in the manufacturing method described above. Note that a step of forming another layer can be added, or a plurality of layers of the same type can be stacked. In any case, it is preferable to perform the step at a temperature of 1100 ° C. or lower.

<Example>
A metal substrate 1 was manufactured by providing a plurality of through holes 1a by laser processing in a central region of a metal plate having a thickness of 0.3 mm and a craft 22APU.

  Next, 60 wt% NiO powder and 40 wt% GDC powder were mixed, and an organic binder and an organic solvent (dispersion medium) were added to prepare a paste. Using the paste, the first electrode layer 2 was laminated in a region having a radius of 3 mm from the center of the metal substrate 1. Note that screen printing was used to form the first electrode layer 2. And the baking process was performed at 850 degreeC with respect to the metal substrate 1 which laminated | stacked the 1st electrode layer 2 (a 1st electrode layer formation step, a diffusion suppression layer formation step).

  Next, an organic binder and an organic solvent (dispersion medium) were added to the fine powder of GDC to prepare a paste. Using the paste, the intermediate layer 3 was laminated in a region having a radius of 5 mm from the center of the metal substrate 1 on which the first electrode layer 2 was laminated by screen printing. Next, after the CIP molding was performed on the metal substrate 1 on which the intermediate layer 3 was laminated, the intermediate layer 3 having a flat surface was formed by performing a baking process at 1050 ° C. (intermediate layer forming step).

  The thickness of the first electrode layer 2 obtained by the above steps was about 10 μm, and the thickness of the intermediate layer 3 was about 10 μm. The metal substrate 1 on which the first electrode layer 2 and the intermediate layer 3 are laminated is a substrate with an electrode layer having gas flowability.

  Subsequently, an 8YSZ (yttria-stabilized zirconia) component having a mode diameter of about 0.7 μm is supplied at a feed rate of 2.4 g / min, on the intermediate layer 3 of the metal substrate 1 so as to cover the intermediate layer 3. The electrolyte layer 4 was formed by spraying while moving the substrate at a scanning speed of 5 mm / second in the range of 15 mm (spray coating). At that time, the metal substrate 1 was not heated (electrolyte layer forming step).

The thickness of the electrolyte layer 4 obtained by the above steps was about 4 to 5 μm. Thus, when the amount of He leak of the metal substrate 1 in the state where the first electrode layer 2, the intermediate layer 3, and the electrolyte layer 4 are laminated is measured under a pressure of 0.2 MPa, the amount of He leak is a detection lower limit (1. 0 mL / min · cm ² ). Therefore, it can be seen that the formed electrolyte layer 4 has gas barrier properties.

  Next, an organic binder and an organic solvent (dispersion medium) were added to the fine powder of GDC to prepare a paste. The reaction preventing layer 5 was formed on the electrolyte layer 4 of the electrochemical element E by screen printing using the paste.

Thereafter, the electrochemical device E on which the reaction preventing layer 5 is formed is subjected to CIP molding at a pressure of 300 MPa, and then subjected to a baking treatment in a reducing atmosphere at 1000 ° C. for 1 hour, whereby the reaction preventing layer 5 having a flat surface is formed. Was formed (reaction prevention layer forming step).

  Moreover, the electron micrograph of the cross section of this electrochemical element E is shown in FIG. As can be seen from this electron micrograph, the reaction preventing layer 5 is formed in a state having a plurality of pore spaces (sites shown in black) inside. As described above, in the sample shown in FIG. 5, there is an uneven shape formed by the recess F and the protrusion G at the interface between the reaction preventing layer 5 and the electrolyte layer 4. A concave portion F1, a convex portion G1, a concave portion F2, a convex portion G2, and a concave portion F3 are formed on the interface in order from the left of the field of view.

  The line segment J1 is a line segment connecting the bottoms of the two recesses F1 and the recesses F2. A region on the side of the electrolyte layer 4 with respect to the line segment J1 is defined as a protruding region K1. A region on the second electrode layer 6 side with respect to the line segment J1 is defined as an adjacent region L1. The height from the line segment J1 at the top of the protruding region K1 is 1.39 μm, which is 0.5 μm or more. And as FIG. 5 shows, there exists more pore space in the protrusion area | region K1 compared with the adjacent area | region L1. Accordingly, the protruding region K1 has a porosity higher than that of the adjacent region L1. Therefore, the protruding region K1 corresponds to the sparse protruding region N.

  In the protruding region K1, which is the sparse protruding region N, the distance between the bottoms of the two concave portions F1 and the concave portions F2 adjacent to each other via the convex portion G1 is 10.5 μm, and is 15 μm or less.

  The line segment J2 is a line segment connecting the bottoms of the two recesses F2 and the recess F3. A region on the side of the electrolyte layer 4 with respect to the line segment J2 is defined as a protruding region K2. A region on the second electrode layer 6 side with respect to the line segment J2 is defined as an adjacent region L2. The height from the line segment J2 at the top of the protruding region K2 is 1.63 μm, which is 0.5 μm or more. And as FIG. 5 shows, more pore space exists in the protrusion area | region K2 compared with the adjacent area | region L2. Accordingly, the protruding region K2 has a porosity higher than that of the adjacent region L2. Therefore, the protruding region K2 corresponds to the sparse protruding region N.

  In the protruding region K2, which is the sparse protruding region N, the distance between the bottoms of the two recessed portions F2 and the recessed portion F3 adjacent to each other via the protruding portion G2 is 10.3 μm, and is 15 μm or less.

  The porosity of the protruding region K1, which is the sparse protruding region N, is estimated to be 15.0% from the electron micrograph of FIG. The porosity of the adjacent region L1 is estimated to be 3.8% from the electron micrograph of FIG. Therefore, the ratio of the porosity of the protruding region K1 to the porosity of the adjacent region L1 is 3.94.

  The porosity of the protruding region K2, which is the sparse protruding region N, is estimated to be 13.1% from the electron micrograph of FIG. The porosity of the adjacent region L2 is estimated to be 2.51% from the electron micrograph of FIG. Therefore, the ratio of the porosity of the protruding region K2 to the porosity of the adjacent region L2 is 5.22.

Second Embodiment
The electrochemical device E, the electrochemical module M, the electrochemical device Y, and the energy system Z according to this embodiment will be described with reference to FIGS.

  As shown in FIG. 2, the electrochemical element E according to the present embodiment has a U-shaped member 7 attached to the back surface of the metal substrate 1, and a cylindrical support is formed by the metal substrate 1 and the U-shaped member 7. doing.

  An electrochemical module M is configured in which a plurality of electrochemical elements E are stacked and assembled with the current collecting member 26 interposed therebetween. The current collecting member 26 is joined to the second electrode layer 6 of the electrochemical element E and the U-shaped member 7 to electrically connect them.

  The electrochemical module M includes a gas manifold 17, a current collecting member 26, a termination member, and a current drawing portion. The assembled electrochemical element E is supplied with gas from the gas manifold 17 with one open end of the cylindrical support connected to the gas manifold 17. The supplied gas flows through the inside of the cylindrical support and is supplied to the first electrode layer 2 through the through hole 1 a of the metal substrate 1.

FIG. 3 shows an outline of the energy system Z and the electrochemical device Y.
The energy system Z includes an electrochemical device Y and a heat exchanger 53 as an exhaust heat utilization unit that reuses the heat discharged from the electrochemical device Y.
The electrochemical device Y includes an electrochemical module M, a desulfurizer 31 and a reformer 34, a fuel supply unit that supplies a fuel gas containing a reducing component to the electrochemical module M, and an electrochemical module. And an inverter 38 for extracting electric power from M.

  Specifically, the electrochemical device Y includes a desulfurizer 31, a reforming water tank 32, a vaporizer 33, a reformer 34, a blower 35, a combustion unit 36, an inverter 38, a control unit 39, a storage container 40, and an electrochemical module M. Have.

  The desulfurizer 31 removes (desulfurizes) sulfur compound components contained in hydrocarbon-based raw fuel such as city gas. When the raw fuel contains a sulfur compound, by providing the desulfurizer 31, the influence of the sulfur compound on the reformer 34 or the electrochemical element E can be suppressed. The vaporizer 33 generates steam from the reformed water supplied from the reformed water tank 32. The reformer 34 steam-reforms the raw fuel desulfurized by the desulfurizer 31 using the steam generated by the vaporizer 33 to generate a reformed gas containing hydrogen.

  The electrochemical module M uses the reformed gas supplied from the reformer 34 and the air supplied from the blower 35 to generate an electrochemical reaction to generate power. The combustion unit 36 mixes the reaction exhaust gas discharged from the electrochemical module M and air, and combusts the combustible component in the reaction exhaust gas.

The electrochemical module M includes a plurality of electrochemical elements E and a gas manifold 17.
The plurality of electrochemical elements E are arranged in parallel while being electrically connected to each other, and one end (lower end) of the electrochemical element E is fixed to the gas manifold 17. The electrochemical element E generates electricity by causing an electrochemical reaction between the reformed gas supplied through the gas manifold 17 and the air supplied from the blower 35.

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

  The vaporizer 33, the reformer 34, the electrochemical module M, and the combustion unit 36 are stored in the storage container 40. The reformer 34 performs the reforming process of the raw fuel using the combustion heat generated by the combustion of the reaction exhaust gas in the combustion unit 36.

  The raw fuel is supplied to the desulfurizer 31 through the raw fuel supply path 42 by the operation of the booster pump 41. The reforming water in the reforming water tank 32 is supplied to the vaporizer 33 through the reforming water supply path 44 by the operation of the reforming water pump 43. The raw fuel supply path 42 is downstream of the desulfurizer 31 and is joined to the reformed water supply path 44, and the reformed water and raw fuel merged outside the storage container 40 are stored in the storage container. The carburetor 33 provided in 40 is supplied.

  The reformed water is vaporized by the vaporizer 33 and becomes steam. The raw fuel containing the steam generated in the vaporizer 33 is supplied to the reformer 34 through the steam-containing raw fuel supply path 45. The raw fuel is steam-reformed by the reformer 34, and a reformed gas (first gas having a reducing component) containing hydrogen gas as a main component is generated. The reformed gas generated in the reformer 34 is supplied to the gas manifold 17 of the electrochemical module M through the reformed gas supply path 46.

  The reformed gas supplied to the gas manifold 17 is distributed to the plurality of electrochemical elements E, and is supplied to the electrochemical elements E from the lower end, which is a connection portion between the electrochemical elements E and the gas manifold 17. Hydrogen (reducing component) in the reformed gas is mainly used for electrochemical reaction in the electrochemical element E. The reaction exhaust gas containing the remaining hydrogen gas that has not been used for the reaction is discharged from the upper end of the electrochemical element E to the combustion section 36.

  The reaction exhaust gas is combusted in the combustion unit 36 and becomes combustion exhaust gas, and is discharged from the combustion exhaust gas outlet 50 to the outside of the storage container 40. A combustion catalyst portion 51 (for example, a platinum-based catalyst) is disposed at the combustion exhaust gas outlet 50 to burn and remove 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 the heat exchanger 53 through the combustion exhaust gas discharge passage 52.

  The heat exchanger 53 exchanges heat between the combustion exhaust gas generated by the combustion in the combustion unit 36 and the supplied cold water to generate hot water. That is, the heat exchanger 53 operates as an exhaust heat utilization unit that reuses the heat exhausted from the electrochemical device Y.

  Instead of the exhaust heat utilization unit, a reaction exhaust gas utilization unit that utilizes the reaction exhaust gas discharged from the electrochemical module M (without being combusted) may be provided. The reaction exhaust gas contains residual hydrogen gas that was not used for the reaction in the electrochemical element E. In the reaction exhaust gas utilization section, the remaining hydrogen gas is used to use heat by combustion, or to generate power by a fuel cell or the like, thereby effectively using energy.

<Third Embodiment>
FIG. 4 shows another embodiment of the electrochemical module M. The electrochemical module M according to this embodiment constitutes the electrochemical module M by stacking and stacking the above-described electrochemical elements E with the inter-cell connecting member 71 interposed therebetween.

  The inter-cell connection member 71 is a plate-like member that has conductivity and does not have gas permeability, and grooves 72 that are orthogonal to each other are formed on the front surface and the back surface. The inter-cell connection member 71 can be made of metal such as stainless steel or metal oxide.

  As shown in FIG. 4, when the electrochemical elements E are stacked and assembled with the inter-cell connection member 71 interposed therebetween, gas can be supplied to the electrochemical elements E through the grooves 72. Specifically, one groove 72 becomes the first gas flow path 72 a and supplies gas to the front side of the electrochemical element E, that is, the second electrode layer 6. The other groove 72 becomes the second gas flow path 72b, and gas is supplied from the back side of the electrochemical element E, that is, the back side surface of the metal substrate 1 to the first electrode layer 2 through the through hole 1a.

  When this electrochemical module M is operated as a fuel cell, oxygen is supplied to the first gas flow path 72a and hydrogen is supplied to the second gas flow path 72b. Then, the reaction as a fuel cell proceeds in the electrochemical element E, and electromotive force / current is generated. The generated electric power is taken out of the electrochemical module M from the inter-cell connection members 71 at both ends of the stacked electrochemical element E.

  In the present embodiment, the grooves 72 that are orthogonal to each other are formed on the front and back surfaces of the inter-cell connection member 71, but the grooves 72 that are parallel to each other can also be formed on the front and back surfaces of the inter-cell connection member 71. .

(Other embodiments)
(1) In the above embodiment, the electrochemical element E is used for a solid oxide fuel cell. However, the electrochemical element E is used for a solid oxide electrolytic cell, an oxygen sensor using a solid oxide, or the like. You can also

(2) In the above embodiment, the metal substrate 1 is used for a metal-supported solid oxide fuel cell using the metal substrate 1 as a support. However, in the present application, the first electrode layer 2 or the second electrode layer 6 is used as a support. It can also be used for an electrode-supported solid oxide fuel cell and an electrolyte-supported solid oxide fuel cell using the electrolyte layer 4 as a support. In those cases, the first electrode layer 2 or the second electrode layer 6 or the electrolyte layer 4 can be made to have a necessary thickness so that a function as a support can be obtained.

(3) In the above embodiments, for example, NiO-GDC as the first electrode layer 2 material, Ni-GDC, NiO-YSZ , Ni-YSZ, a composite material such as _{CuO-CeO 2, Cu-CeO} 2 used, As the material of the second electrode layer 6, for example, a complex oxide such as LSCF or LSM was used. The electrochemical device E configured as described above supplies hydrogen gas to the first electrode layer 2 as a fuel electrode (anode), and supplies air to the second electrode layer 6 as an air electrode (cathode). It can be used as an oxide fuel cell. By changing this configuration, the electrochemical element E can be configured such that the first electrode layer 2 can be an air electrode and the second electrode layer 6 can be a fuel electrode. That is, for example, a composite oxide such as LSCF or LSM is used as the material of the first electrode layer 2, and the material of the second electrode layer 6 is, for example, NiO-GDC, Ni-GDC, NiO-YSZ, Ni-YSZ, CuO-CeO. ₂ and a composite material such as Cu—CeO ₂ are used. In the case of the electrochemical element E configured as described above, air is supplied to the first electrode layer 2 to form an air electrode, hydrogen gas is supplied to the second electrode layer 6 to form a fuel electrode, and the electrochemical element E is solid. It can be used as an oxide fuel cell.

  Note that the configurations disclosed in the above embodiments can be applied in combination with the configurations disclosed in other embodiments as long as no contradiction arises. The embodiments disclosed in this specification are exemplifications, and the embodiments of the present invention are not limited thereto, and can be modified as appropriate without departing from the object of the present invention.

  It can be used as an electrochemical element and a solid oxide fuel cell.

1: Metal substrate (metal support)
1a: Through-hole 2: Electrode layer 3: Intermediate layer 4: First electrolyte layer (counter electrode layer)
4a: Electrolyte layer upper side surface 5: Reaction preventing layer 6: Second electrode layer (electrode layer)
B: Substrate with electrode layer E: Electrochemical element F: Recess
G: convex portion J: line segment K: protruding region L: adjacent region M: electrochemical module N: sparse protruding region Y: electrochemical device Z: energy system

Claims (19)

An electrochemical element having an electrolyte layer, an electrode layer, and a reaction preventing layer disposed between the electrolyte layer and the electrode layer,
The reaction preventing layer has a concavo-convex shape formed from a concave portion and a convex portion at the interface with the electrolyte layer,
In the reaction preventing layer, a region on the electrolyte layer side is defined as a protruding region with respect to a line segment connecting the bottoms of two adjacent concave portions via the convex portion, and the electrode layer side with respect to the line segment. Region as an adjacent region,
An electrochemical element, wherein a height of the top of the projecting region from the line segment is 0.5 μm or more and a sparse projecting region that is a projecting region having a porosity larger than the porosity of the adjacent region exists.   2. The electrochemical device according to claim 1, wherein in the sparse projecting region, a distance between bottom portions of two concave portions adjacent to each other through the convex portion is 15 μm or less.   The electrochemical device according to claim 1 or 2, wherein a porosity of the sparsely protruding region is 10% or more and 30% or less.   The electrochemical device according to any one of claims 1 to 3, wherein a porosity of the adjacent region is 1% or more and 20% or less.   The electrochemical element according to any one of claims 1 to 4, wherein a ratio of a porosity of the sparse protruding region to a porosity of the adjacent region is 1.5 or more and 15 or less.   The electrochemical device according to any one of claims 1 to 5, wherein the reaction preventing layer contains Ce.   The electrochemical device according to any one of claims 1 to 6, wherein the reaction preventing layer contains at least one element selected from the group consisting of Sm, Gd, and Y.   8. The method according to claim 1, wherein the reaction preventing layer contains at least one element selected from the group consisting of Sm, Gd, and Y, and the total content of these elements is 5 mol% or more and 25 mol% or less. The electrochemical element of Claim 1.   The electrochemical element according to any one of claims 1 to 8, wherein a thickness of the reaction preventing layer is larger than 1 µm and not larger than 100 µm.   The electricity according to any one of claims 1 to 9, wherein the electrode layer is a perovskite oxide containing two or more elements selected from the group consisting of La, Sr, Sm, Mn, Co, and Fe. Chemical element.   The electrochemical element according to any one of claims 1 to 10, wherein the electrolyte layer contains zirconia ceramics.   The counter electrode layer serving as a counter electrode of the electrode layer is provided on the reaction side and the side where the reaction preventing layer and the electrode layer of the electrolyte layer are disposed. The electrochemical element as described.   The electrochemical device according to claim 1, wherein the electrochemical device is supported by a metal support.   The electrochemical module arrange | positioned in the state which the electrochemical element of any one of Claim 1 to 13 gathered.   The electrochemical apparatus which has a fuel supply part which has at least the electrochemical module and reformer of Claim 14, and supplies the fuel gas containing a reducing component with respect to the said electrochemical module.   An electrochemical device comprising the electrochemical module according to claim 14 and an inverter that extracts electric power from the electrochemical module.   An energy system comprising: the electrochemical device according to claim 15 or 16; and an exhaust heat utilization unit that reuses heat exhausted from the electrochemical device.   A solid oxide fuel cell comprising the electrochemical element according to claim 12, wherein the counter electrode layer is a fuel electrode or an air electrode, and the electrode layer is an air electrode or a fuel electrode. A method for producing an electrochemical device comprising a metal support, an electrolyte layer, an electrode layer, and a reaction preventing layer disposed between the electrolyte layer and the electrode layer,
The manufacturing method which bakes the said reaction prevention layer at 1100 degrees C or less.