WO2015068223A1 - Collector, method for producing collector, solid electrolyte fuel cell electrode with collector, solid electrolyte fuel cell solid electrolyte fuel cell, and solid electrolyte fuel cell stack structure - Google Patents

Abstract

This collector is applied to a solid electrolyte fuel cell electrode. The collector is provided with a microparticle-containing layer containing electrode material particles comprising an electrode material forming an electrode of a solid electrolyte fuel cell electrode and collector substrate material particles comprising a collector substrate material forming a collector substrate on a collector substrate. The collector substrate material particles and electrode material particles are in direct contact, some or all of the collector substrate material particles are a portion of the collector substrate, and some or all of the electrode material particles are a portion of the electrode layer of the solid electrolyte fuel cell electrode.

Description

Current collector and method for producing current collector, electrode for solid oxide fuel cell with current collector, solid oxide fuel cell single cell, solid oxide fuel cell stack structure

The present invention relates to a current collector and a method for producing the current collector, a solid electrolyte fuel cell electrode with a current collector, a solid oxide fuel cell single cell, and a solid oxide fuel cell stack structure. More specifically, the present invention relates to a current collector applied to a solid oxide fuel cell electrode, a method for producing the current collector, and a solid oxide fuel cell electrode with a current collector to which the current collector is applied. The present invention relates to a solid oxide fuel cell single cell and a solid oxide fuel cell stack structure.

A fuel cell is a device that converts chemical energy into electrical energy through an electrochemical reaction. A solid oxide fuel cell, which is one of such fuel cells, has a three-layer structure in which layers of a fuel electrode, a solid electrolyte, and an air electrode are stacked. The solid oxide fuel cell can generate electricity by supplying a fuel gas such as hydrogen or hydrocarbon from the outside to the fuel electrode and supplying an oxidant gas such as air to the air electrode. it can.

In addition, the air electrode and the fuel electrode are provided with a current collecting layer on the electrode surfaces. These current collecting layers can maintain a good energized state even when exposed to a high temperature environment, that is, have a low temperature dependency of volume resistivity and a high corrosion resistance. Is desired.

On the other hand, for example, when using a metal member such as stainless steel, it is known that the contact resistance with the electrode is gold-plated to improve the contact resistance of the interface. It is known to apply platinum plating as an antioxidant film for electronic parts.

On the other hand, an electrical interconnector device for a solid oxide fuel cell, the interconnector device comprising a stainless steel substrate and a protective oxide film deposited on the substrate, wherein the protective film is Cu (x) Mn (Y) An interconnector device including O (z), where x = 1, 1.6 ≦ y ≦ 2.4, and z = 4 has been proposed (see Patent Document 1).

Japanese National Table 2010-535290

However, even when a protective film containing a spinel compound such as Cu (x) Mn (y) O (z) is provided on the current collector, the more the layer, in other words, the more the interface, the more the peeling Since the factors increase, suppression of the occurrence of peeling has been a problem.

Further, when the present inventors examined platinum plating on the current collector, chromium and iron contained in the current collector diffused in the platinum plating layer in the temperature range of 650 ° C. or higher, and platinum was removed. There was a problem that oxides of chromium and iron were generated on the surface of the plating layer, and the electron conductivity was remarkably impaired. Furthermore, diffusion of chromium and iron changes the coefficient of thermal expansion and causes layer destruction due to the difference in coefficient of thermal expansion.

The present invention has been made in view of such problems of the conventional technology. And, the present invention provides a current collector that can maintain a good energized state even when exposed to a high temperature environment, a method for producing the current collector, and a solid with a current collector to which the current collector is applied It is an object of the present invention to provide an electrode for an electrolyte fuel cell, a solid oxide fuel cell single cell, and a solid electrolyte fuel cell stack structure.

The inventors of the present invention made extensive studies to achieve the above object. As a result, the current collecting base contains fine particles including current collecting base material particles comprising the current collecting base material forming the current collecting base and electrode material particles comprising the electrode material forming the electrode layer of the solid oxide fuel cell electrode. The current collector base material particles and the electrode material particles are in direct contact, and all or part of the current collector base material particles are part of the current collector base, and all or part of the electrode material particles are It has been found that the above object can be achieved by adopting a structure that is a part of the electrode layer of the solid oxide fuel cell electrode, and the present invention has been completed.

That is, the current collector of the present invention is applied to a solid oxide fuel cell electrode. And this collector is an electrode material which consists of the electrode material which forms the electrode layer of the current collection base material particle which consists of current collection base material which forms a current collection base, and the electrode for solid oxide type fuel cells on a current collection base A fine particle-containing layer containing particles is provided. Further, the current collector base material particles and the electrode material particles are in direct contact, and all or part of the current collector base material particles are part of the current collector base, and all or part of the electrode material particles are solid electrolytes. It is a part of electrode layer of the electrode for type fuel cells.

The electrode for a solid oxide fuel cell with a current collector of the present invention comprises the current collector of the present invention. The electrode for a solid oxide fuel cell with a current collector includes a current collector base material particle made of a current collector base material forming the current collector base and an electrode layer of the solid oxide fuel cell electrode on the current collector base. It has a structure in which a fine particle-containing layer including electrode material particles made of an electrode material to be formed and an electrode layer of a solid oxide fuel cell electrode are laminated in this order. Further, the current collector material particles and the electrode material particles are in direct contact, and all or part of the current collector material particles are part of the current collector base, and all or part of the electrode layer material particles are solid. It is a part of electrode layer of the electrode for electrolyte type fuel cells.

Furthermore, the solid oxide fuel cell unit cell of the present invention comprises the above-described electrode for a solid oxide fuel cell with a current collector of the present invention. The solid oxide fuel cell single cell includes a solid electrolyte and two electrodes that sandwich the solid electrolyte. Further, at least one of the two electrodes is formed of a current collector base material particle made of a current collector base material forming the current collector base and an electrode material forming an electrode layer of a solid oxide fuel cell electrode on the current collector base. The electrode layer of the solid electrolyte fuel cell electrode and the electrode layer of the solid oxide fuel cell electrode are opposed to the solid electrolyte. It has a structure arranged in a state. Furthermore, the current collector material particles and the electrode material particles are in direct contact, and all or part of the current collector material particles are part of the current collector base, and all or part of the electrode layer material particles are solid. It is a part of electrode layer of the electrode for electrolyte type fuel cells.

Further, the fuel cell stack structure of the present invention comprises the above-described solid oxide fuel cell single cell of the present invention. The fuel cell stack structure includes at least two single cells, and has a stack structure in which two single cells are stacked directly or via a separator. In addition, at least one single cell of at least two single cells includes a solid electrolyte and two electrodes that sandwich the solid electrolyte. Further, at least one of the two electrodes is made of a current collector base material particle made of a current collector base material forming the current collector base and an electrode material forming an electrode layer of a solid oxide fuel cell electrode on the current collector base. The electrode layer of the solid electrolyte fuel cell electrode and the electrode layer of the solid oxide fuel cell electrode are opposed to the solid electrolyte. It has a structure arranged in a state. Further, the current collector material particles and the electrode material particles are in direct contact, and all or part of the current collector material particles are part of the current collector base, and all or part of the electrode layer material particles are solid. It is a part of electrode layer of the electrode for electrolyte type fuel cells.

Furthermore, the manufacturing method of the 1st electrical power collector of this invention is a 1st method of manufacturing the said electrical power collector of this invention, Comprising: The following process (A) is included.
Step (A): Electrode material particles made of an electrode material for forming an electrode layer of a solid oxide fuel cell electrode on a current collecting substrate, or current collecting substrate material particles made of a current collecting substrate material for forming a current collecting substrate; Mixed particles containing electrode material particles made of an electrode material forming an electrode layer of a solid oxide fuel cell electrode are collided.

Moreover, the manufacturing method of the 2nd electrical power collector of this invention is a 2nd method of manufacturing the said electrical power collector of this invention, Comprising: The following process (B1) and (B2) are included.
Step (B1): Current collecting substrate material particles made of a current collecting substrate material forming the current collecting substrate are collided with the current collecting substrate.
Step (B2): electrode material particles made of an electrode material forming an electrode layer of a solid oxide fuel cell electrode, or a current collector base material forming a current collector base, which is implemented after the step (B1). The mixed particles including the electrode material particles made of the electrode material forming the electrode layer of the electrode substrate material particles and the electrode layer of the electrode for the solid oxide fuel cell are collided.

Furthermore, the third method for producing a current collector of the present invention is a third method for producing the current collector of the present invention, and includes the following steps (C1) to (C3).
Step (C1): Current collecting substrate material particles made of the current collecting substrate material forming the current collecting substrate are collided with the current collecting substrate.
Step (C2): Conducted after step (C1), comprising current collecting substrate material particles comprising a current collecting substrate material forming a current collecting substrate, and electrode material forming an electrode layer of a solid oxide fuel cell electrode. The mixed particles including the electrode material particles are collided.
Step (C3): Electrode material particles made of an electrode material that forms the electrode layer of the electrode for the solid oxide fuel cell, which is implemented after the step (C2), are collided.

According to the present invention, the current collecting base material particles comprising the current collecting base material forming the current collecting base and the electrode material particles comprising the electrode material forming the electrode layer of the solid oxide fuel cell electrode are formed on the current collecting base. The current collector base material particles and the electrode material particles are in direct contact with each other, and all or part of the current collector base material particles are part of the current collector base. A part was a part of the electrode layer of the electrode for the solid oxide fuel cell. Therefore, a current collector capable of maintaining a good energized state even when exposed to a high temperature environment, a method for producing the current collector, and a solid oxide fuel cell with a current collector to which the current collector is applied Electrode, solid oxide fuel cell unit cell, and solid oxide fuel cell stack structure can be provided.

FIG. 1 is a cross-sectional view schematically showing a current collector according to the first embodiment of the present invention. FIG. 2 is an enlarged view schematically showing a portion surrounded by a surrounding line A of the current collector shown in FIG. FIG. 3 is an enlarged view schematically showing the same portion of the current collector according to the second embodiment of the present invention as the portion surrounded by the surrounding line A in FIG. FIG. 4 is a plan view schematically showing an example of a fuel cell to which the fuel cell stack structure according to the fourth embodiment of the present invention is applied. FIG. 5 is a cross-sectional view schematically showing a cross section taken along line BB of the fuel cell shown in FIG. 6 is a cross-sectional image of the electrode for a solid oxide fuel cell with a current collector of Example 1 taken by a scanning ion microscope (SIM). FIG. 7 is a cross-sectional image taken by a transmission electron microscope (TEM) of a portion surrounded by an encircling line C of the electrode for the solid oxide fuel cell with a current collector shown in FIG. FIG. 8 is a diagram showing a nickel mapping result of a cross section by energy dispersive X-ray spectroscopic analysis (EDX) of a portion surrounded by an encircling line C of the electrode for the solid oxide fuel cell with a current collector shown in FIG. . FIG. 9 is a planar image of the current collector in Example 1 and Reference Example 1 using a stereomicroscope. FIG. 10 is a graph showing the rate of increase in resistance before and after firing the current collector at 900 ° C. in each example.

Hereinafter, a current collector according to an embodiment of the present invention, a method for manufacturing the current collector, an electrode for a solid electrolyte fuel cell with a current collector, a solid oxide fuel cell single cell, and a solid oxide fuel cell stack structure This will be described in detail with reference to the drawings. In addition, the dimension ratio of drawing is exaggerated on account of description, and may differ from an actual ratio.

(First embodiment)
First, the current collector according to the first embodiment will be described in detail. FIG. 1 is a cross-sectional view schematically showing a current collector according to the first embodiment. As shown in FIG. 1, a current collector 1 of this embodiment is applied to a solid oxide fuel cell electrode, and includes a current collector base 2 and a fine particle-containing layer formed on the current collector base 2. 4. In addition, 6 shown with a dotted line in a figure is an electrode layer of the electrode for solid oxide fuel cells with a collector.

FIG. 2 is an enlarged view schematically showing a portion surrounded by an encircling line A of the current collector shown in FIG. As shown in FIG. 2, the fine particle-containing layer 4 includes a current collector base material particle 4 a made of a current collector base material that forms the current collector base 2, and a solid oxide fuel cell electrode with a current collector indicated by a dotted line in the figure. It includes electrode material particles 4 b made of an electrode material that forms the electrode layer 6. Further, in the fine particle-containing layer 4, the current collector base material particles 4a and the electrode material particles 4b are in direct contact, and all or part of the current collector base material particles 4a are part of the current collector base 2, and the electrode All or part of the material particles 4b are part of the electrode layer 6 of the electrode for the solid oxide fuel cell with a current collector.

As described above, the current collector base material particles that are part of the current collector base and the electrode material particles that are part of the electrode layer of the electrode for the solid oxide fuel cell with a current collector are in direct contact with each other. The bondability between the current collector and the electrode is improved, and a good energized state is maintained even when exposed to a high temperature environment. In other words, since there is no protective layer that becomes a resistance factor between the current collector and the electrode and the structure is directly joined, even when the peeling is suppressed and exposed to a high temperature environment. A good energized state is maintained. And in a solid oxide fuel cell single cell or a solid oxide fuel cell stack to which such a current collector is applied, an increase in resistance is suppressed and an improvement in output can be realized.

Here, in the present invention, “the current collecting base material for forming the current collecting base” means a material for forming the current collecting base itself. For example, when the current collecting base is made of a copper alloy, the current collecting base material is merely a copper alloy, and does not mean the copper constituting the copper alloy and the alloy additive element.

In the present invention, the “electrode material for forming the electrode layer” means a material for forming the electrode layer itself. For example, when the electrode layer is made of lanthanum strontium cobalt ferrite (La _1-x Sr _x Co _1-y Fe _y O ₃ : LSCF), the electrode material is only lanthanum strontium cobalt ferrite (La _1-x Sr _x Co _{1 -y} Fe _y O _3: a LSCF), lanthanum strontium cobalt ferrite _{(La 1-x Sr x Co} 1-y Fe y O 3: LSCF) lanthanum oxide and strontium oxide constituting, cobalt oxide, It does not mean iron oxide. However, when the electrode layer is made of cermet of nickel (Ni) and yttria stabilized zirconia (YSZ), the electrode material is nickel (Ni) and yttria stabilized zirconia (YSZ). This interpretation is the same for the above “collecting substrate material forming the collecting substrate”.

Further, in the present invention, “all or part of the current collecting base material particles are part of the current collecting base” means that all or part of the current collecting base material particles are directly or via the current collecting base material particles. Means that the electrode material particles are all or part of the electrode layer of the electrode for the solid oxide fuel cell with a current collector. It means that all or part of the particles are in contact with the electrode layer of the electrode for the solid oxide fuel cell with a current collector directly or via the electrode material particles.

Hereinafter, each configuration will be described in more detail.

Examples of the current collector base 2 include those formed from current collector base materials such as heat-resistant alloys, corrosion-resistant alloys, corrosion-resistant steels, and stainless steels (SUS) containing nickel (Ni) and chromium (Cr). However, the present invention is not limited to these, and a current collecting base made of a conventionally known material applied to a solid oxide fuel cell can be applied.

Examples of the fine particle-containing layer 4 include, for example, current collecting base material particles 4a made of the above-described current collecting base material, and electrode material particles made of an electrode material that forms an electrode layer of a solid oxide fuel cell electrode with a current collector. 4b, and these are not particularly limited as long as they have the predetermined structure described above. Therefore, the electrode to which the current collector is applied may be either one or both of the fuel electrode and the air electrode. However, even when exposed to a high temperature environment, the current-carrying performance is reduced due to oxidation. In consideration of suppression or prevention, the effect of the present invention is more easily exhibited when applied to the air electrode exposed to the oxidizing gas.

Examples of the electrode material include platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru), nickel (Ni), cobalt (Co), silver (Ag), gold (Au), and beryllium ( Metals such as Be), carbon (C), silicon (Si), iron (Fe), iridium (Ir), cesium (Cs), rhenium (Re), copper (Cu), lanthanum strontium cobaltite (La _1-x Sr _x CoO ₃ : LSC), lanthanum strontium cobalt ferrite (La _1-x Sr _x Co _1-y Fe _y O ₃ : LSCF), samarium strontium cobaltite (Sm _x Sr _1-x CoO ₃ : SSC), lanthanum strontium manganite _{(La 1-x Sr x MnO} 3: LSM), lanthanum calcium manganite (La _-X Ca _x MnO _3), praseodymium strontium manganite _{(Pr 1-x Sr x MnO} 3), lanthanum strontium manganese cobaltite _{((La 1-x Sr x} Mn 1-y Co y O 3), lanthanum strontium manganese chromate _{(La 1-x Sr x Mn} 1-y Cr y O 3), lanthanum calcium cobaltite _{((La 1-x Ca x} CoO 3), praseodymium cobaltite (PrCoO _3), lanthanum nickel bis chromite (LaNi _1-x Bi _x O ₃ ), indium tin oxide (In _{2 -z} Sn _z O ₃ ), indium zirconium oxide (In _1-x Zr _x O ₃ ), ruthenium oxide / zirconium oxide (RuO ₂ / ZrO ₂ ), etc. An oxide having a perovskite structure, silver (Ag), (Au), beryllium (Be), carbon (C), silicon (Si), iron (Fe), platinum (Pt), iridium (Ir), cesium (Cs), rhenium (Re) or copper (Cu) or these Alloys containing metals in any combination, silver (Ag) and copper (Cu), tin (Sn), tellurium (Te), beryllium (Be), magnesium (Mg), cobalt (Co) and niobium (Nb) An alloy containing at least one metal selected from the group consisting of:

In the present embodiment, the fine particle-containing layer 4 includes at least one component element of the current collector base material forming the current collector base and at least one of the electrode materials forming the electrode layer of the solid oxide fuel cell electrode. It is preferable not to include particles containing various component elements, and include only particles made of a current collecting substrate material forming a current collecting substrate and particles made of an electrode material forming an electrode layer of a solid oxide fuel cell electrode. More preferably. In the current collector of the present invention, the fine particle-containing layer includes particles made of a current collecting substrate material forming a current collecting substrate and particles made of an electrode material forming an electrode layer of a solid oxide fuel cell electrode. Including particles containing a composite material comprising at least one component element of the current collector substrate material forming the current collector substrate and at least one component element of the electrode material forming the electrode layer of the electrode for the solid oxide fuel cell By not having a structure, since particles containing a composite having a lower electronic conductivity than that of the current collector base material that can be generated by the reaction between the current collector base material and the electrode material are not included, there is a decrease in electron conductivity. It is suppressed. And in a solid oxide fuel cell single cell or a solid oxide fuel cell stack to which such a current collector is applied, an increase in resistance is suppressed and an improvement in output can be realized.

Here, as a representative example of the composite, current collecting base material particles forming a current collecting base and electrode material particles forming an electrode layer of a solid oxide fuel cell electrode are formed by a conventionally known sputtering method or the like. When the fine particle-containing layer is used to form the fine particle-containing layer, there can be mentioned those composed of components constituting the current collecting base material and the electrode material contained in the initial layer formed in the initial stage. In addition, although not particularly limited, when the fine particle-containing layer is formed by an aerosol deposition method, a powder jet deposition method, a warm spray method, a thermal spray method, a cold spray method, etc., which will be described later, an initial layer is hardly formed. The fine particle-containing layer is preferably formed by these methods.

Furthermore, in the present embodiment, it is preferable that all or part of the fine particle-containing layer 4 is at least one of a dense body and a porous body having a pore size of 0.1 μm or less. Thus, even if it is a dense body or a porous body, the pore diameter is 0.1 μm or less, so that intrusion of oxidizing gas into the fine particle-containing layer can be suppressed or prevented, and the surface of the current collecting substrate Oxide film growth is suppressed, and an increase in resistance can be suppressed. When the pore size of the porous body is larger than 0.1 μm, the possibility that the oxidizing gas enters the fine particle-containing layer at a high temperature increases, and the resistance may increase.

That is, when the oxidizing gas permeates through the fine particle-containing layer and an oxide film is formed on the surface of the current collecting substrate, the electron conductivity is lowered. Therefore, for example, it is preferable that the fine particle-containing layer is a dense body, or even if it is a porous body, its pore diameter is in a range in which Knudsen diffusion is dominant. Considering oxygen (O ₂ ) at 750 ° C. as an example of the oxidizing gas at high temperature when using the fuel cell, the average free path of oxygen (O ₂ ) at 750 ° C. and 1 atm is 0.19 μm. By setting the pore size of the material to 0.1 μm or less, intrusion of oxygen (O ₂ ) can be suppressed or prevented. In order to make the pore diameter of the porous body 0.1 μm or less, for example, the particle diameter of the particles constituting the porous body may be 0.2 μm or less. Further, in a solid oxide fuel cell single cell or a solid oxide fuel cell stack to which such a current collector is applied, an increase in resistance is suppressed, and an improvement in output can be realized.

Here, in the present invention, the “particle diameter” means, for example, the first air electrode material particle or the second particle observed using an observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM). It means the maximum distance among the distances between any two points on the contour line of the (observation surface) such as air electrode material particles. In the present invention, the value of “average particle diameter” is observed in several to several tens of fields using an observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM). The value calculated as the average value of the particle diameter of the particles shall be adopted.

In the present embodiment, the fine particle-containing layer 4 preferably has a thickness of 0.1 to 2 μm. Thus, the fall of the output density in a battery can be suppressed by making a fine particle content layer into a very thin composition. Further, in a solid oxide fuel cell single cell or a solid oxide fuel cell stack to which such a current collector is applied, an increase in resistance is suppressed, and an improvement in output can be realized. When the thickness of the fine particle-containing layer is less than 0.1 μm, the structural stability may be inferior, and the gas sealing performance may not be sufficiently exhibited. In addition, when the thickness of the fine particle-containing layer exceeds 2 μm, if the fine particle-containing layer exhibits gas sealing performance, the contribution to power generation is very small, and thus the output improvement effect may be reduced.

(Second Embodiment)
Next, the current collector according to the second embodiment will be described in detail. In addition, about the thing equivalent to what was demonstrated in said form, the code | symbol same as them is attached | subjected and description is abbreviate | omitted. FIG. 3 is an enlarged view schematically showing the same portion of the current collector according to the second embodiment of the present invention as the portion surrounded by the surrounding line A in FIG. As shown in FIG. 3, the current collector 1 of the present embodiment includes a current collector base 4 that forms the current collector base 2 as the distance from the current collector base 2 increases in the thickness direction of the microparticle containing layer 4. The configuration having a composition gradient structure in which the content ratio of the electric base material particles 4a is different from the above-described embodiment.

Thus, the current collector base material particles that are part of the current collector base and the electrode material particles that are part of the electrode layer of the electrode for the solid oxide fuel cell with current collector are in direct contact, and Because of the composition having a predetermined composition gradient structure, the bonding property and the structural stability between the current collector and the electrode are improved, and a good energized state is maintained even when exposed to a high temperature environment. . In other words, there is no protective layer that becomes a resistance factor between the current collector and the electrode, and since it is directly bonded, peeling is suppressed, and layer destruction due to a difference in thermal expansion coefficient is less likely to occur. Even when exposed to a high temperature environment, a better energized state is maintained. And in a solid oxide fuel cell single cell or a solid oxide fuel cell stack to which such a current collector is applied, an increase in resistance is suppressed and an improvement in output can be realized.

(Third embodiment)
Next, a method for manufacturing a current collector according to the third embodiment will be described in detail. Specific examples of the current collector manufacturing method include the following first to third current collector manufacturing methods.

The first current collector manufacturing method comprises, on a current collecting substrate, electrode material particles made of an electrode material forming an electrode layer of a solid oxide fuel cell electrode, or a current collecting substrate material forming a current collecting substrate. A step (A) of causing the mixed particles including the electrode material particles made of the electrode material that forms the electrode layer of the current collector base material particles and the electrode layer of the solid oxide fuel cell electrode to collide.

The second current collector manufacturing method includes a step (B1) of causing the current collector substrate to collide with a current collector substrate material made of a current collector substrate material forming the current collector substrate, and a step (B1) after the step (B1). Conducted electrode material particles made of an electrode material forming an electrode layer of a solid oxide fuel cell electrode, or current collecting substrate material particles made of a current collecting substrate material forming a current collecting substrate, and a solid oxide fuel cell And a step (B2) of colliding mixed particles including electrode material particles made of an electrode material forming an electrode layer of the electrode.

Further, the third current collector manufacturing method includes a step (C1) of colliding current collector base material particles made of a current collector base material forming the current collector base with the current collector base, and a step (C1). The mixed particles containing the current collecting base material particles made of the current collecting base material forming the current collecting base and the electrode material particles made of the electrode material forming the electrode layer of the electrode for the solid oxide fuel cell are collided later. A step (C2) and a step (C3), which is carried out after the step (C2), and collides with electrode material particles made of an electrode material forming the electrode layer of the electrode for the solid oxide fuel cell.

In any of the first to third current collector manufacturing methods, for example, an aerosol processing method, a powder jet deposition method, a warm spray method, a thermal spray method, a cold spray method, or the like is used. By colliding the current collecting base material particles or the electrode material particles with the current collecting base or the like, the fine particle-containing layer can be formed on the current collecting base, so that the process can be simplified. Specifically, submicron-sized powdery current collecting base material particles and electrode material particles are flown at an optimum flow rate (for example, 300 to 950 m / hour) with a carrier gas such as helium (He) gas or nitrogen (N ₂ ) gas. s.), the kinetic energy of the particles is instantaneously converted into heat, and a fine particle-containing layer containing the current collecting substrate material particles and the electrode material particles is formed. . In the initial stage, the oxide formed on the surface of the current collecting substrate can be removed by adjusting the flow rate to be faster than the optimum flow rate. Further, the adhesion between the current collecting substrate and the fine particle-containing layer can be improved by adjusting the flow rate and embedding the current collecting substrate material particles and the electrode material particles in the current collecting substrate.

Further, although any of the first to third current collector manufacturing methods can form the fine particle-containing layer having the composition gradient structure, the second or third current collector manufacturing method By adopting, a fine particle-containing layer having a composition gradient structure can be formed more easily.

(Fourth embodiment)
Next, the solid oxide fuel cell stack structure according to the fourth embodiment will be described in detail. Further, the electrode for the solid oxide fuel cell with the current collector and the single cell for the solid oxide fuel cell will be described together. In addition, about the thing equivalent to what was demonstrated in said form, the code | symbol same as them is attached | subjected and description is abbreviate | omitted. FIG. 4 is a plan view schematically showing an example of a fuel cell to which the fuel cell stack structure according to the fourth embodiment of the present invention is applied. FIG. 5 is a cross-sectional view schematically showing a cross section taken along line BB of the fuel cell shown in FIG.

As shown in FIGS. 4 and 5, the fuel cell FC includes a solid oxide fuel cell stack structure 21 in which four solid oxide fuel cell single cells 11 are stacked, a gas introduction part 22a, and a gas discharge part 22b. And a case 22 having a cylindrical shape that introduces air from the gas introduction part 22a and flows it to the gas discharge part 22b in a state in which the solid oxide fuel cell stack structure 21 is accommodated.

The solid oxide fuel cell unit cell 11 constituting the solid oxide fuel cell stack structure 21 of the fuel cell FC is a thin plate and a metal (having a gas introduction hole 31 and a gas discharge hole 32 at the center) ( A cell plate 12 made of SUS430) and a metal (SUS430) separator plate 13 that is thin and circular like the cell plate 12 and has a gas introduction hole 41 and a gas discharge hole 42 in the center. The cell plate 12 and the separator plate 13 are joined to each other with their outer peripheral edges facing each other, and a bag portion (space) S formed between the cell plate 12 and the separator plate 13 has a metal A current collecting member 14 made of a mesh (made of Inconel) is accommodated.

The outer peripheral edge portions of the cell plate 12 and the separator plate 13 that are joined to face each other are concentric with the outer peripheral edge portion and project in a direction approaching each other to form a space S. The steps 34 and 44 are formed by pressing. The outer peripheral edges of the cell plate 12 and the separator plate 13 are joined by laser welding.

Further, each central portion of the cell plate 12 and the separator plate 13 is provided with a gas introduction channel 61 communicating with the gas introduction hole 31, and the space S formed between the cell plate 12 and the separator plate 13. A metal (SUS) flow path component 15 for supplying fuel gas is housed, and a gas discharge flow path 62 communicating with the gas discharge hole 32 is provided to discharge the fuel gas from the space S. As will be described later, these flow path components 15 and 15 are solid electrolytes in a state in which the solid oxide fuel cell unit cells 11 are stacked to form the solid oxide fuel cell stack structure 21. The fuel cell stack structure 21 is in close contact with each other only by the pressing force of the whole. In addition, the flow path member 15 is also fixed to the cell plate 12 and the separator plate 13 by diffusion bonding in a vacuum at a bonding temperature of 1000 ° C. or less, and deformation at the time of bonding is prevented. In addition, instead of diffusion bonding, bonding by laser welding using a YAG laser is also possible. At this time, since the cell plate 12 and the separator plate 13 are thin plates, they can be bonded even if they are irradiated with laser from the front side. it can. The flow path pattern of the flow path component 15 can be formed by etching, grinding, or laser processing, and can also be formed by stacking and joining etched components.

A plurality of stacked solid oxide fuel cell single cells 11 are sandwiched by flanges 23 and 24 from above and below, and a plurality of gas discharge holes 32 and 42 formed around the gas introduction holes 31 and 41 of the cell plate 12 and the separator plate 13. A plurality of stud bolts (not shown) are respectively inserted into the upper flange 23 having the fuel gas introduction pipe 23a, and one end of the stud bolt is screwed into the lower flange having the fuel gas exhaust pipe 24a. The nuts are screwed into the other end portions of the stud bolts projecting from 24 through a disc spring, so that the solid oxide fuel cell unit cells 11 stacked on each other are fastened together.

At this time, a ceramic adhesive 27 as a seal bonding material is applied in a double ring shape between the central portions of the solid oxide fuel cell single cells 11 overlapping each other. Note that a glass-based adhesive or a gasket formed by adding ceramic fibers or filler to glass can be used as the seal bonding material.

In this fuel cell FC, the stack structure 21 formed as described above by the SUS430 case 22 divided from each other is sandwiched from above and below in FIG. Each of the discharge portions 22b is welded to accommodate the solid oxide fuel cell stack structure 21 in the case 22. At this time, between the solid oxide fuel cell stack structure 21 and the case 22 is accommodated. A solid electrolyte fuel cell in which the air introduced from the gas introduction part 22a overlaps each other in the solid oxide fuel cell stack structure 21 by providing a filler 26 as a gas flow restriction part made of fire-resistant foamed cement in the gap. It is made to flow through the air electrode 17 of the single cell 11 to the gas discharge part 22b.

In this fuel cell FC, as shown in FIGS. 4 and 5, when air is introduced from the gas introduction part 22 a into the case 22, the air flows into the air electrode of the solid oxide fuel cell stack structure 21, and then the gas is discharged. Each space is formed between the cell plate 12 and the separator plate 13 through the introduction pipe 23a of the flange 23 and the gas introduction holes 31 and 41 of the solid oxide fuel cell single cell 11 while being exhausted through the portion 22b. After being introduced into S and flowing through the space S, the gas is exhausted through the gas discharge holes 32 and 42 and the exhaust pipe 24 a of the flange 24.

In the fuel cell FC described above, the air introduced from the gas introduction part 22a of the case 22 is more mutually in the solid oxide fuel cell stack structure 21 than in the gap between the case 22 and the solid oxide fuel cell stack structure 21. It becomes easy to flow to the portion of the air electrode 17 of the overlapping solid oxide fuel cell single cell 11, and the amount of air supplied to the portion of the solid oxide fuel cell single cell 11 held on the cell plate 12 is greatly increased. Therefore, sufficient power generation output can be obtained.

In the fuel cell FC described above, only the fuel gas is allowed to flow in the space S formed between the cell plate 12 and the separator plate 13 of the solid oxide fuel cell unit cell 11 of the solid oxide fuel cell stack structure 21. As a result, unburned gas can be recovered. Therefore, even if the gas flow changes during transient operation, the fuel utilization rate does not decrease. The possibility that a malfunction occurs due to local thermal stress applied to the single fuel cell 11 is reduced.

Further, the current collector 1 having the above-described configuration disposed on the air electrode 17 side of the solid oxide fuel cell unit cell 11 is used as the separator plate 13 in this embodiment. The four solid oxide fuel cell single cells 11 include a solid electrolyte 16, and an air electrode 17 and a fuel electrode 18 that are two electrodes that sandwich the solid electrolyte 16. A fine particle-containing layer 19 is formed on the surface of the separator plate 13 facing the air electrode 17. These solid electrolyte fuel cell single cells 11 may be any of an electrolyte support cell, an electrode support cell, and a porous support cell.

As the air electrode 17, one that is strong in an oxidizing atmosphere, permeates an oxidant gas, has high electrical conductivity, and has a catalytic action to convert oxygen molecules into oxide ions can be suitably used. Moreover, even if it consists of an electrode catalyst, it may consist of a cermet of an electrode catalyst and electrolyte material. For example, a metal such as silver (Ag) or platinum (Pt) may be used as the electrode catalyst, but lanthanum strontium cobaltite (La _1-x Sr _x CoO ₃ : LSC) or lanthanum strontium cobalt ferrite ( _{La 1-x Sr x Co 1} -y Fe y O 3: LSCF), samarium strontium cobaltite _{(Sm x Sr 1-x CoO} 3: SSC), lanthanum strontium manganite _{(La 1-x Sr x MnO} 3: LSM It is preferable to apply a perovskite oxide such as However, it is not limited to these, and conventionally known air electrode materials can be applied. In addition, these can be applied individually by 1 type or in combination of multiple types. Furthermore, examples of the electrolyte material include, but are not limited to, cerium oxide (CeO ₂ ), zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ), and lanthanum oxide (La ₂ O ₃ ). It is not a thing, but the mixture with oxides, such as various stabilized zirconia mentioned later and a ceria solid solution, can be used suitably.

Further, as the solid electrolyte 16, those having gas impermeability and the ability to pass oxide ions without passing electrons can be suitably used. Examples of the constituent material of the solid electrolyte include yttria (Y ₂ O ₃ ), neodymium oxide (Nd ₂ O ₃ ), samaria (Sm ₂ O ₃ ), gadria (Gd ₂ O ₃ ), and scandia (Sc ₂ O ₃ ). It is possible to apply stabilized zirconia in which these are dissolved. Also, ceria solid solutions such as samaritan doped ceria (SDC), yttria doped ceria (YDC), and gadria doped ceria (GDC), bismuth oxide (Bi ₂ O ₃ ), lanthanum strontium magnesium gallate (La _1-x Sr _x Ga _1-y Mg _y O ₃ : LSMG) or the like can also be applied.

As the fuel electrode 18, a fuel electrode that is strong in a reducing atmosphere, permeates the fuel gas, has high electrical conductivity, and has a catalytic action for converting hydrogen molecules into protons can be suitably used. As a constituent material of the fuel electrode, for example, a metal such as nickel (Ni) may be applied alone, but a cermet mixed with an oxide ion conductor typified by yttria stabilized zirconia (YSZ) is used. It is preferable to apply, thereby increasing the reaction area and improving the electrode performance. At this time, a ceria solid solution such as samaria doped ceria (SDC) or gadria doped ceria (GDC) can be applied instead of yttria stabilized zirconia (YSZ).

Hereinafter, the present invention will be specifically described based on examples, comparative examples, and reference examples.

Example 1
<Preparation of current collector>
First, a supersonic nozzle for film formation and a current collector base (material: SUS430 alloy) were placed inside a vacuum chamber, and then the pressure was reduced to 1 Pa or less to make the inside of the vacuum chamber a non-oxidizing atmosphere. Next, electrode material particles (material: lanthanum strontium cobalt ferrite (La _1-x Sr _x Co _1-y Fe _y O ₃ ; LSCF, particle size: 0.8 μm, crystal structure: perovskite structure) at a flow rate of 850 m / s. The oxide layer present on the surface of the current collector substrate was removed by impinging on the current collector substrate by being ejected from a supersonic nozzle in a helium (He) gas, and then the electrode material particles were flowed at a flow rate of 800 m / s. A fine particle-containing layer is formed on the surface of the current collector substrate by an aerosol deposition method in which the current collector substrate is collided with the current collector substrate by being injected from a supersonic nozzle on a helium (He) gas of Obtained.

<Preparation of solid oxide fuel cell electrode with current collector>
Next, the electrode material particles are placed on helium (He) gas at a flow rate of 600 m / s and are ejected from a supersonic nozzle so as to collide with the fine particle-containing layer of the current collector. A layer was formed to obtain a solid oxide fuel cell electrode with a current collector of this example.

The obtained solid oxide fuel cell electrode with current collector was observed with a scanning ion microscope (SIM). 6 is a cross-sectional image of the electrode for a solid oxide fuel cell with a current collector of Example 1 taken by a scanning ion microscope (SIM). From FIG. 6, it was confirmed that the electrode layer 6 was formed on the current collector base 2.

Further, the interface between the current collector base and the electrode layer of the obtained solid oxide fuel cell electrode with a current collector was observed with a transmission electron microscope (TEM), and further a cross section with energy dispersive X-ray spectroscopic analysis (EDX). The mapping of nickel. FIG. 7 is a cross-sectional image taken by a transmission electron microscope (TEM) of a portion surrounded by an encircling line C of the electrode for the solid oxide fuel cell with a current collector shown in FIG. FIG. 8 is a diagram showing a mapping result of nickel in a cross section by energy dispersive X-ray spectroscopic analysis of a portion surrounded by an encircling line C of the electrode for the solid oxide fuel cell with a current collector shown in FIG.

7 and 8, it was confirmed that the fine particle-containing layer 4 containing the current collector material particles and the electrode material particles dispersed therein was formed between the current collector base 2 and the electrode layer 6. . Although FIG. 8 shows the mapping result of nickel, only nickel which is one component element of the current collecting base material is not dispersed. The dispersion of SUS430, which is a current collector substrate material, could be confirmed by detailed component analysis in the region surrounded by a circle in FIG. The vertical and horizontal lengths in FIGS. 7 and 8 are the same.

Further, as shown in FIG. 7, in the fine particle-containing layer, since a porous structure could not be confirmed, ultrafine pores having a pore size of 0.1 μm or less are dense bodies or even porous bodies. Presumed to have. In ultrafine pores, the pore diameter is less than the mean free path of the gas, and Knudsen diffusion is dominant. Since the mean free path of gas is 1 atm and 750 ° C., nitrogen (N ₂ ) is 0.145 μm and oxygen (O ₂ ) is 0.19 μm, the pore diameter in the fine particle-containing layer of Example 1 is Knudsen It is assumed that (Knudsen) diffusion is the dominant range. In such a range where Knudsen diffusion is dominant, nitrogen (N ₂ ) and oxygen (O ₂ ) diffuse while colliding with the pore wall surface, so that there is no large kinetic energy, for example, a large pressure difference. The gas cannot move from inside the pores. That is, the fine particle-containing layer is presumed to have gas sealing properties.

Therefore, the obtained current collector was baked in the atmosphere at 900 ° C. for 1 hour to confirm the effect of suppressing oxidation by the fine particle-containing layer. FIG. 9 is a planar image of the current collector in Example 1 and Reference Example 1 using a stereomicroscope. Reference Example 1 is an example in which the current collector substrate itself is used as a current collector. 9 (a) and 9 (b) are plan images obtained by a stereoscopic microscope before and after firing the current collector of Reference Example 1, respectively. FIGS. 9 (c) and 9 (d) are those of Example 1, respectively. It is a plane image by the stereomicroscope before baking of a collector and after baking. In the current collector of Reference Example 1, it was confirmed that a red oxide film was formed by firing. On the other hand, in the current collector of Example 1, the surface of the fine particle-containing layer was not changed even by firing, and it was confirmed that the fine particle-containing layer functions as an antioxidant layer.

Since it was confirmed that the fine particle-containing layer in the current collector of Example 1 functions as an antioxidant layer, the resistance increase rates were compared for the samples of each example. Here, the increasing ratio of resistance (Increasing Ratio) is measured by measuring the resistance at room temperature before and after the firing process in which the temperature is raised to 900 ° C. in 4 hours, held at 900 ° C. for 1 hour, and then naturally cooled to room temperature. It is calculated. The obtained result is shown in FIG. Moreover, the samples of Comparative Example 1 and Comparative Example 2 in the figure were produced as follows.

(Comparative Example 1)
<Preparation of current collector>
A part of the current collector base (material: SUS430 alloy) was immersed in a plating bath containing chloroplatinic acid, and a platinum (Pt) plating layer was formed under predetermined conditions to obtain a current collector of this example.

(Comparative Example 2)
<Preparation of current collector>
Manganese (II) nitrate hexahydrate is sprayed onto the surface of the current collector substrate (material: SUS430 alloy) to form a film, then sintered at 350 to 400 ° C., and then at 800 ° C. or higher. The current collector of this example was obtained through reduction treatment and oxidation treatment.

From FIG. 10, the current collector of Example 1 belonging to the scope of the present invention was exposed to a higher temperature environment than the current collectors of Comparative Example 1, Comparative Example 2 and Reference Example 1 outside the present invention. Even in this case, it was found that the increase in resistance is suppressed.

Such effects were obtained because (1) the electrode layer and the current collecting substrate were directly joined, so that no resistance factor was generated between the electrode layer and the current collecting substrate, and (2) containing fine particles (3) The electrode material material particles and the current collecting base material particles in the fine particle-containing layer are dispersed in the layer, so that the thermal expansion coefficient of the entire fine particle-containing layer is increased by the electrode. This is considered to be due to the fact that the thermal expansion changes gradually from the current collecting substrate toward the electrode layer, and the separation between the current collecting substrate and the electrode layer is suppressed.

As mentioned above, although this invention was demonstrated by some embodiment and an Example, this invention is not limited to these, A various deformation | transformation is possible within the range of the summary of this invention.

That is, in the above-described embodiment, the solid electrolyte that constitutes a single cell of the fuel cell is described as an example using a solid electrolyte having oxide ion conductivity, but is not limited thereto. That is, for example, a solid electrolyte material having proton conductivity such as zirconium phosphate, tungsten phosphate, and silica phosphate, or a solid electrolyte using a solid electrolyte material such as a serate-based perovskite, a zirconate-based perovskite, or a scandiate-based perovskite is provided. The present invention can also be applied to a fuel cell.

FC fuel cell 1 current collector 2 current collector base 4 fine particle-containing layer 4a current collector base material particle 4b electrode material particle 6 electrode layer 11 solid oxide fuel cell single cell 12 cell plate 13 separator plate 14 current collector 15 flow channel component 16 Solid electrolyte 17 Air electrode 18 Fuel electrode 21 Solid electrolyte fuel cell stack structure 22 Case 22a Gas introduction part 22b Gas discharge part 23, 24 Flange 23a Introduction pipe 24a Exhaust pipe 26 Filler 27 Ceramic adhesives 31, 41 Gas Introduction holes 32, 42 Gas discharge holes 34, 44 Annular step 61 Gas introduction flow path 62 Gas discharge flow path

Claims (11)

A current collector applied to a solid oxide fuel cell electrode,
A fine particle-containing layer comprising, on a current collecting base, current collecting base material particles comprising the current collecting base material forming the current collecting base and electrode material particles comprising the electrode material forming the electrode layer of the electrode for the solid oxide fuel cell. With
The current collector base material particles and the electrode material particles are in direct contact,
All or part of the current collector base material particles is part of the current collector base,
A current collector, wherein all or part of the electrode material particles are part of an electrode layer of the electrode for a solid oxide fuel cell. The fine particle-containing layer contains at least one component element of the current collector substrate material forming the current collector substrate and at least one component element of the electrode material forming the electrode layer of the solid oxide fuel cell electrode The current collector according to claim 1, wherein the current collector does not contain particles to be collected. 3. The current collector according to claim 1, wherein all or part of the fine particle-containing layer is at least one of a dense body and a porous body having a pore diameter of 0.1 μm or less. The fine particle-containing layer has a composition gradient structure in which the content ratio of current collecting substrate material particles forming the current collecting substrate decreases as the distance from the current collecting substrate increases in the thickness direction of the fine particle-containing layer. The current collector according to any one of claims 1 to 3, characterized in that: The current collector according to any one of claims 1 to 4, wherein the fine particle-containing layer has a thickness of 0.1 to 2 µm. An electrode for a solid oxide fuel cell with a current collector provided with a current collector applied to the electrode for a solid oxide fuel cell according to any one of claims 1 to 5,
A fine particle-containing layer comprising, on a current collecting base, current collecting base material particles comprising the current collecting base material forming the current collecting base and electrode material particles comprising the electrode material forming the electrode layer of the electrode for the solid oxide fuel cell. And the electrode layer of the electrode for the solid oxide fuel cell are laminated in this order,
The current collector material particles and the electrode material particles are in direct contact,
All or part of the current collector material particles are part of the current collector base,
An electrode for a solid oxide fuel cell with a current collector, wherein all or part of the electrode layer material particles are part of an electrode layer of the electrode for a solid oxide fuel cell. A solid oxide fuel cell single cell comprising the electrode for a solid oxide fuel cell with a current collector according to claim 6,
A solid electrolyte, and two electrodes sandwiching the solid electrolyte,
Electrode material in which at least one of the two electrodes forms a current collector base material particle made of a current collector base material forming the current collector base and an electrode layer of the solid oxide fuel cell electrode on the current collector base A fine particle-containing layer containing electrode material particles and an electrode layer of a solid oxide fuel cell electrode are laminated in this order,
The electrode layer of the solid oxide fuel cell electrode has a structure disposed in a state of facing the solid electrolyte,
The current collector material particles and the electrode material particles are in direct contact,
All or part of the current collector material particles are part of the current collector base,
A solid oxide fuel cell unit cell, wherein all or part of the electrode layer material particles are part of an electrode layer of the electrode for a solid oxide fuel cell. A solid oxide fuel cell stack structure comprising the solid oxide fuel cell single cell according to claim 7,
Comprising at least two single cells,
The two single cells have a stack structure laminated directly or via a separator,
At least one single cell of the at least two single cells includes a solid electrolyte and two electrodes sandwiching the solid electrolyte,
Electrode material in which at least one of the two electrodes forms a current collector base material particle made of a current collector base material forming the current collector base and an electrode layer of the solid oxide fuel cell electrode on the current collector base A fine particle-containing layer containing electrode material particles and an electrode layer of a solid oxide fuel cell electrode are laminated in this order,
The electrode layer of the solid oxide fuel cell electrode has a structure disposed in a state of facing the solid electrolyte,
The current collector material particles and the electrode material particles are in direct contact,
All or part of the current collector material particles are part of the current collector base,
A solid oxide fuel cell stack structure, wherein all or part of the electrode layer material particles are part of an electrode layer of the electrode for the solid oxide fuel cell. A method for producing a first current collector applied to the electrode for a solid oxide fuel cell according to any one of claims 1 to 5,
Electrode material particles made of an electrode material for forming an electrode layer of the electrode for a solid oxide fuel cell on the current collector base, or current collector base material particles made of a current collector base material for forming the current collector base, and the solid electrolyte A method for producing a current collector, comprising a step (A) of colliding mixed particles including electrode material particles made of an electrode material forming an electrode layer of a fuel cell electrode. A method for producing a second current collector applied to the electrode for a solid oxide fuel cell according to any one of claims 1 to 5,
A step (B1) of causing the current collector substrate to collide with current collector substrate material particles comprising the current collector substrate material forming the current collector substrate, and the solid oxide fuel cell, which is performed after the step (B1). Electrode material particles comprising an electrode material forming an electrode layer of the electrode, or current collecting substrate material particles comprising a current collecting substrate material forming the current collecting substrate, and an electrode forming an electrode layer of the solid oxide fuel cell electrode The manufacturing method of the electrical power collector characterized by including the process (B2) which collides the mixed particle containing the electrode material particle which consists of material. A third current collector manufacturing method applied to the solid oxide fuel cell electrode according to any one of claims 1 to 5,
A step (C1) of causing a current collector substrate to collide with a current collector substrate material made of a current collector substrate material that forms the current collector substrate;
The electrode material comprising the current collector base material particles comprising the current collector base material forming the current collector base and the electrode material forming the electrode layer of the solid oxide fuel cell electrode, which is implemented after the step (C1). A step of colliding mixed particles including particles (C2), and a step of colliding electrode material particles made of an electrode material forming an electrode layer of the electrode for a solid oxide fuel cell, which is performed after the step (C2). (C3) is included. The manufacturing method of the electrical power collector characterized by the above-mentioned.

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