WO2022196053A1

WO2022196053A1 - Solid oxide fuel cell and method for producing same

Info

Publication number: WO2022196053A1
Application number: PCT/JP2022/000685
Authority: WO
Inventors: 李新宇
Original assignee: 太陽誘電株式会社
Priority date: 2021-03-19
Filing date: 2022-01-12
Publication date: 2022-09-22
Also published as: JP2022145221A

Abstract

The present invention is provided with: a solid electrolyte layer; an anode which is provided on the lower surface of the solid electrolyte layer, and comprises a porous body that is provided with an anode catalyst, while containing an electron conductive ceramic and an oxide ion conductive ceramic; a first mixed layer which is provided on the lower surface of the anode, and has a structure wherein a metal material and a ceramic material are mixed with each other; a first supporting body which is provided on the lower surface of the first mixed layer, and is mainly composed of a metal; a cathode which is provided on the upper surface of the solid electrolyte layer, and comprises a porous body that is provided with a cathode catalyst, while containing an electron conductive ceramic and an oxide ion conductive ceramic; a second mixed layer which is provided on the upper surface of the cathode, and has a structure wherein a metal material and a ceramic material are mixed with each other; and a second supporting body which is provided on the upper surface of the second mixed layer, and is mainly composed of a metal.

Description

Solid oxide fuel cell and manufacturing method thereof

The present invention relates to a solid oxide fuel cell and its manufacturing method.

　In order to develop a solid oxide fuel cell system that can be used in automobiles, etc., it is desired to develop a cell that can withstand vibration and not crack even when the temperature rises rapidly. Therefore, metal support type solid oxide fuel cells have been developed (see, for example, Patent Documents 1 and 2).

Japanese Patent Publication No. 2004-512651 Japanese Patent Application Laid-Open No. 2020-21646

However, due to the structural difference between the anode and the cathode, there is a difference in thermal expansion coefficient, which may cause the solid oxide fuel cell to warp during firing.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a solid oxide fuel cell that can suppress the occurrence of warping and a method for manufacturing the same.

A solid oxide fuel cell according to the present invention comprises: a solid electrolyte layer containing a solid oxide having oxide ion conductivity; and an anode having an anode catalyst in the porous body, and a structure in which the anode is provided on the side opposite to the solid electrolyte layer and a metal material and a ceramic material are mixed. a first mixed layer, a first support provided on a surface of the first mixed layer opposite to the solid electrolyte layer and containing a metal as a main component; a cathode having a porous body containing a conductive ceramic and an oxide ion conductive ceramic, and having a cathode catalyst in the porous body; and a second support provided on the surface of the second mixed layer opposite to the solid electrolyte layer and having a metal as a main component. and

The warp amount of the solid oxide fuel cell may be less than 3%.

In the above solid oxide fuel cell, an insulating member covering the outer peripheries of the first support, the first mixed layer, the anode, the solid electrolyte layer, the cathode, the second mixed layer and the second support may be provided.

In the above-described solid oxide fuel cell, the solid oxide fuel cell has a substantially rectangular shape in plan view, and the insulating member comprises a surface of the first support opposite to the first mixed layer and a surface of the first support. Extending to the surface of the second support opposite to the second mixed layer, the length of the extension is defined as distance a, and the length of one side of the solid oxide fuel cell is defined as length b. , a/b may be 1/10 or less.

In the above solid oxide fuel cell, the insulating member may be glass.

In the above solid oxide fuel cell, the insulating member penetrates from the outer periphery of the first support, the first mixed layer, the anode, the cathode, the second mixed layer, and the second support to the inside. You may have

In the solid oxide fuel cell described above, the anode catalyst may be Ni and GDC, and the cathode catalyst may contain at least one of PrO _x , LSM, LSC, and GDC.

In the above solid oxide fuel cell, each of the anode catalyst and the cathode catalyst may have an average particle size of 100 nm or less.

In the above solid oxide fuel cell, among the porosity of the first support, the porosity of the first mixed layer, and the porosity of the anode, the following relationship is satisfied: first support>first mixed layer> The relationship of the anode is established, and among the porosity of the second support, the porosity of the second mixed layer, and the porosity of the cathode, the second support>the second mixed layer>the A cathodic relationship may also be established.

In the solid oxide fuel cell, the thickness of the first support > the first mixed layer > the anode is such that the thickness of the first support > the first mixed layer > the anode. A relationship is established between the thickness of the second support, the thickness of the second mixed layer, and the thickness of the cathode: second support>second mixed layer>cathode. may

In the above solid oxide fuel cell, the crystal grain size of the metal component of the first support and the second support is larger than the crystal grain size of the metal component of the first mixed layer and the second mixed layer. may

In the above solid oxide fuel cell, the porous body may have a porosity of 20% or more in the cross-sectional areas of the anode and the cathode.

In the above solid oxide fuel cell, the thickness of the anode and the cathode may be 2 μm or more.

In the porous bodies of the anode and the cathode of the solid oxide fuel cell, the cross-sectional area ratio of the ion-conducting ceramics and the electron-conducting ceramics may be 1:9 to 9:1.

In the method for manufacturing a solid oxide fuel cell according to the present invention, an electronically conductive ceramics material powder and an oxide ion conductive ceramics material are coated on both sides of an electrolyte green sheet containing a solid oxide material powder having oxide ion conductivity. firing a laminate in which an electrode green sheet containing a powder, a mixed layer green sheet containing a ceramic material powder and a metal material powder, and a support green sheet containing a metal powder are laminated; and firing the electrode green sheet. and a step of impregnating the porous body obtained by the above with a catalyst.

In the above method for producing a solid oxide fuel cell, before the step of impregnating with the catalyst, the support obtained by firing the support green sheet, the mixed layer obtained by firing the mixed layer green sheet, and the A step of covering the outer periphery of the porous body with an insulating member may be included.

According to the present invention, it is possible to provide a solid oxide fuel cell that can suppress the occurrence of warping and a method for manufacturing the same.

FIG. 2 is a schematic cross-sectional view illustrating a layered structure of a solid oxide fuel cell; FIG. 3 is an enlarged cross-sectional view illustrating details of the first support, first mixed layer, anode, cathode, second mixed layer, and second support; FIG. 4 is a diagram for explaining the amount of warpage of a fuel cell; (a) and (b) are figures which illustrate an interconnector. 1 is a diagram illustrating a flow of a method for manufacturing a fuel cell; FIG. FIG. 5 is a schematic cross-sectional view illustrating the laminated structure of a fuel cell according to a second embodiment; FIG. 6 is a diagram illustrating the flow of a method for manufacturing a fuel cell according to the second embodiment; (a) and (b) are diagrams for explaining the details of the insulating member forming process.

Embodiments will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic cross-sectional view illustrating the layered structure of a solid oxide fuel cell 100 according to the first embodiment. As illustrated in FIG. 1, the fuel cell 100 includes an anode 30 on the first surface (lower surface) of a solid electrolyte layer 40 and a first mixed layer 20 on the surface of the anode 30 opposite to the solid electrolyte layer 40. , the first support 10 is provided on the surface of the first mixed layer 20 opposite to the solid electrolyte layer 40, the cathode 50 is provided on the second surface (upper surface) of the solid electrolyte layer 40, and the solid electrolyte layer 40 of the cathode 50 and the It has a structure in which the second mixed layer 60 is provided on the opposite side, and the second support 70 is provided on the side of the second mixed layer 60 opposite to the solid electrolyte layer 40 . A plurality of fuel cells 100 may be stacked to form a fuel cell stack.

The solid electrolyte layer 40 is a gas-impermeable, gas-impermeable, gas-impermeable, gas-impermeable, gas-impermeable dense solid layer. The solid electrolyte layer 40 is preferably made mainly of scandia-yttria-stabilized zirconium oxide (ScYSZ) or the like. When the concentration of Y ₂ O ₃ +Sc ₂ O ₃ is between 6 mol % and 15 mol %, the highest oxide ion conductivity is obtained, and it is desirable to use materials with this composition. Moreover, the thickness of the solid electrolyte layer 40 is preferably 20 μm or less, more preferably 10 μm or less. The thinner the electrolyte, the better, but a thickness of 1 μm or more is desirable in order to prevent gas from leaking from both sides.

FIG. 2 is an enlarged cross-sectional view illustrating details of the first support 10, the first mixed layer 20, the anode 30, the cathode 50, the second mixed layer 60, and the second support 70. FIG.

The first support 10 is a member that has gas permeability and can support the first mixed layer 20 , the anode 30 , the solid electrolyte layer 40 , the cathode 50 and the second mixed layer 60 . The first support 10 is a metal porous body, such as an Fe--Cr alloy porous body.

The anode 30 is an electrode having electrode activity as an anode, and has a porous ceramic material (electrode skeleton). The porous body does not contain any metal component. With this configuration, the decrease in the porosity of the anode due to coarsening of the metal component is suppressed during firing in a high-temperature reducing atmosphere. In addition, alloying with the metal component of the first support 10 is suppressed, and deterioration of the catalytic function is suppressed.

The porous body of anode 30 has electronic conductivity and oxide ion conductivity. Anode 30 contains electronically conductive ceramics 31 . The electronically conductive ceramics 31 is, for example, a perovskite-type oxide having a compositional formula of _ABO3 , wherein the A site is at least one selected from the group of Ca, Sr, Ba, and La, and the B site is At least one perovskite oxide selected from Ti and Cr can be used. The molar ratio of A sites to B sites may be B≧A. Specifically, a LaCrO ₃ -based material, a SrTiO ₃ -based material, or the like can be used as the electron conductive ceramics 31 .

Moreover, the porous body of the anode 30 contains oxide ion conductive ceramics 32 . The oxide ion conductive ceramics 32 is ScYSZ or the like. For example, it is preferable to use ScYSZ having a composition range of 5 mol % to 16 mol % of scandia (Sc ₂ O ₃ ) and 1 mol % to 3 mol % of yttria (Y ₂ O ₃ ). ScYSZ in which the combined amount of scandia and yttria is 6 mol % to 15 mol % is more preferable. This is because oxide ion conductivity is highest in this composition range. The oxide ion conductive ceramics 32 is, for example, a material having an oxide ion transport number of 99% or higher. GDC or the like may be used as the oxide ion conductive ceramics 32 . In the example of FIG. 2, the same solid oxide as the solid oxide contained in the solid electrolyte layer 40 is used as the oxide ion conductive ceramics 32 .

As illustrated in FIG. 2, in the anode 30, for example, an electron conductive ceramic 31 and an oxide ion conductive ceramic 32 form a porous body. This porous body forms a plurality of voids. An anode catalyst is supported on the surface of the porous body in the void portion. Therefore, a plurality of anode catalysts are spatially dispersed and arranged in the porous body that is spatially continuously formed. A composite catalyst is preferably used as the anode catalyst. For example, as a composite catalyst, oxide ion conductive ceramics 33 and catalyst metal 34 are preferably supported on the surface of a porous body. Examples of oxide ion conductive ceramics 33 include Y-doped BaCe _1-x Zr _x O ₃ (BCZY, x=0 to 1), Y-doped SrCe _1-x Zr _x O ₃ (SCZY, x=0 to 1), Sr-doped LaScO ₃ (LSS), GDC, and the like can be used. Ni or the like can be used as the catalyst metal 34 . The oxide ion conductive ceramics 33 may have the same composition as the oxide ion conductive ceramics 32, but may have a different composition. Note that the metal that functions as the catalyst metal 34 may be in the form of a compound when power is not being generated. For example, Ni may be in the form of NiO (nickel oxide). These compounds are reduced by the reducing fuel gas supplied to the anode 30 during power generation, and take the form of metals that function as anode catalysts.

The first mixed layer 20 contains a metal material 21 and a ceramic material 22 . In the first mixed layer 20, the metal material 21 and the ceramic material 22 are randomly mixed. Therefore, a structure in which a layer of the metal material 21 and a layer of the ceramic material 22 are laminated is not formed. A plurality of voids are also formed in the first mixed layer 20 . The metal material 21 is not particularly limited as long as it is metal. In the example of FIG. 2, the same metal material as that of the first support 10 is used as the metal material 21 . As the ceramic material 22, electronic conductive ceramics 31, oxide ion conductive ceramics 32, or the like can be used. For example, as the ceramic material 22, ScYSZ, GDC, SrTiO3 _- based materials, LaCrO3 _- based materials, etc. can be used. Since SrTiO ₃ -based materials and LaCrO ₃ -based materials have high electronic conductivity, the ohmic resistance in the first mixed layer 20 can be reduced.

The cathode 50 is an electrode having electrode activity as a cathode, and has a porous ceramic material (electrode skeleton). The porous body does not contain any metal component. The porous body of the cathode 50 has electronic conductivity and oxide ion conductivity. Cathode 50 contains electronically conductive ceramics 51 . The electronically conductive ceramic 51 is, for example, a perovskite-type oxide having a compositional formula of _ABO3 , wherein the A site is at least one selected from the group of Ca, Sr, Ba, and La, and the B site is At least one perovskite oxide selected from Ti and Cr can be used. The molar ratio of A sites to B sites may be B≧A. Specifically, a LaCrO ₃ -based material, a SrTiO ₃ -based material, or the like can be used as the electron conductive ceramics 51 . The electronically conductive ceramics 51 preferably contains the same components as the electronically conductive ceramics 31, and preferably has the same composition ratio.

Moreover, the porous body of the cathode 50 contains oxide ion conductive ceramics 52 . The oxide ion conductive ceramics 52 is ScYSZ or the like. For example, it is preferable to use ScYSZ having a composition range of 5 mol % to 16 mol % of scandia (Sc ₂ O ₃ ) and 1 mol % to 3 mol % of yttria (Y ₂ O ₃ ). ScYSZ in which the combined amount of scandia and yttria is 6 mol % to 15 mol % is more preferable. This is because oxide ion conductivity is highest in this composition range. The oxide ion conductive ceramics 52 is, for example, a material having an oxide ion transport number of 99% or higher. GDC or the like may be used as the oxide ion conductive ceramics 52 . The oxide ion conductive ceramics 52 preferably contains the same components as the oxide ion conductive ceramics 32, and preferably has the same composition ratio. In the example of FIG. 2, the same solid oxide as the solid oxide contained in the solid electrolyte layer 40 is used as the oxide ion conductive ceramics 52 .

As illustrated in FIG. 2, in the cathode 50, for example, an electronically conductive ceramics 51 and an oxide ion conductive ceramics 52 form a porous body. This porous body forms a plurality of voids. A cathode catalyst 53 is supported on the surface of the porous body in the void portion. Therefore, the plurality of cathode catalysts 53 are spatially dispersed and arranged in the spatially continuous porous body. Praseodymium oxide (PrO _x ), LSM (lanthanum strontium manganite), LSC (lanthanum strontium cobaltite), or the like can be used as the cathode catalyst 53 . LSM is a Sr-doped LaMnO3 _- based material. LSM is a Sr-doped LaCoO3 _- based material.

The second mixed layer 60 contains a metal material 61 and a ceramic material 62 . In the second mixed layer 60, the metal material 61 and the ceramic material 62 are randomly mixed. Therefore, a structure in which a layer of the metal material 61 and a layer of the ceramic material 62 are laminated is not formed. A plurality of voids are also formed in the second mixed layer 60 . The metal material 61 is not particularly limited as long as it is metal. In the example of FIG. 2, the same metal material as that of the second support 70 is used as the metal material 61 . As the ceramics material 62, electronically conductive ceramics 51, oxide ion conductive ceramics 52, or the like can be used. For example, as the ceramic material 62, ScYSZ, GDC, SrTiO3 _- based materials, LaCrO3 _- based materials, etc. can be used. Since SrTiO ₃ -based materials and LaCrO ₃ -based materials have high electronic conductivity, the ohmic resistance in the second mixed layer 60 can be reduced.

The second support 70 is a member that has gas permeability and can support the second mixed layer 60 , the cathode 50 , the solid electrolyte layer 40 , the anode 30 and the first mixed layer 20 . The second support 70 is a metal porous body, such as an Fe--Cr alloy porous body.

Fuel cell 100 generates power by the following actions. The second support 70 is supplied with an oxidant gas containing oxygen, such as air. The oxidant gas reaches cathode 50 via second support 70 and second mixed layer 60 . At the cathode 50, oxygen that reaches the cathode 50 reacts with electrons supplied from an external electric circuit to form oxide ions. The oxide ions conduct through the solid electrolyte layer 40 and move to the anode 30 side. On the other hand, the first support 10 is supplied with a hydrogen-containing fuel gas such as hydrogen gas or reformed gas. The fuel gas reaches anode 30 via first support 10 and first mixed layer 20 . The hydrogen that reaches the anode 30 emits electrons at the anode 30 and reacts with oxide ions that are conducted through the solid electrolyte layer 40 from the cathode 50 side to become water (H ₂ O). The emitted electrons are extracted outside by an external electric circuit. The electrons taken out are supplied to the cathode 50 after performing electrical work. Electric power is generated by the above action.

In the above power generation reaction, the catalyst metal 34 functions as a catalyst in the reaction between hydrogen and oxide ions. The electronically conductive ceramics 31 conducts electrons obtained by the reaction between hydrogen and oxide ions. The oxide ion conductive ceramics 32 conducts oxide ions that reach the anode 30 from the solid electrolyte layer 40 . The cathode catalyst 53 functions as a catalyst in a reaction in which oxide ions are generated from oxygen gas and electrons. Electronically conductive ceramics 51 are responsible for conducting electrons from an external electrical circuit. The oxide ion conductive ceramics 52 is responsible for conduction of oxide ions to the solid electrolyte layer 40 .

A fuel cell can be produced by laminating each layer using a powder material and firing them simultaneously. However, if there is a large difference in shrinkage behavior between the layers during the firing process, warping as illustrated in FIG. 3 occurs. If the fuel cells are warped, stress is generated in each fuel cell when stacking a plurality of fuel cells to form a stack, and the fuel cells are likely to crack.

It should be noted that, as illustrated in FIG. 3, when the cell is placed on a flat surface, the distance between both sides that come into contact with the surface is defined as a distance B. Let distance A be the vertical distance from the vertex of the warp to the flat surface. Let L be the thickness of the cell. In this case, the amount of warpage T (%) is defined as (A−L)/B×100 (%).

In the fuel cell 100 according to this embodiment, both the anode 30 and the cathode 50 are porous bodies made of electronically conductive ceramics and oxygen ion conductive ceramics. In this configuration, structural differences between anode 30 and cathode 50 are reduced. A first mixed layer 20 is provided on the anode side, and a second mixed layer 60 is provided on the cathode side. Furthermore, a first support 10 is provided on the anode side, and a second support 70 is provided on the cathode side. Thus, the fuel cell 100 has a symmetrical structure with the solid electrolyte layer 40 as the center. As a result, the difference in shrinkage behavior of each layer during the firing process is reduced, and warping is suppressed. For example, the warp amount T (%) is within 3%.

In addition, since the first support 10 mainly composed of metal is provided on the anode side and the second support 70 mainly composed of metal is provided on the cathode side, an example is shown in FIG. The contact resistance with the interconnector 80 is lowered, and the ohmic resistance can be reduced. In addition, in FIG. 4A, the anode 30 and the cathode 50 are connected to the interconnector via the current collector 82 . Also, as illustrated in FIG. 4(b), by welding the interconnector 80 to the anode 30 and the cathode 50, the ohmic resistance can be further reduced. For example, as exemplified in FIG. 4B, the interconnector 80 is welded to the anode 30 and the cathode 50 via the welding points 81 . By using the welding technique, even if the surface of the metal is covered with an oxide film, the internal metal parts are electrically connected, so the internal resistance becomes almost zero, and the contact resistance becomes almost zero. goes down. For example, if the cathode is made of conductive ceramics without providing a support on the cathode side, the contact resistance between the cathode and the interconnector increases. Also, the cathode and the interconnector cannot be welded.

Note that if both the anode 30 and the cathode 50 are porous bodies made of electron-conducting ceramics and oxygen-ion-conducting ceramics, the difference in structure between the anode 30 and the cathode 50 becomes smaller. Anode 30 and cathode 50 can be fired simultaneously. As a result, the adhesion of the anode 30 and the cathode 50 to the solid electrolyte layer 40 is improved, film peeling is suppressed, and the ohmic resistance of the fuel cell 100 as a whole is reduced. Also, by using the above-mentioned materials for the porous bodies of the anode 30 and the cathode 50, firing in a reducing atmosphere is possible.

In addition, since the fuel cell 100 includes the first support 10 and the second support 70 mainly composed of metal, it has a structure that is resistant to thermal shock, mechanical shock, and the like. Moreover, since the first mixed layer 20 contains the metal material 21 and the ceramic material 22, it has both the material properties of metal and the material properties of ceramics. Therefore, the first mixed layer 20 has high adhesion with the first support 10 and has high adhesion with the anode 30 . As described above, delamination between the first support 10 and the anode 30 can be suppressed. Since the second mixed layer 60 contains the metal material 61 and the ceramic material 62, it has both the material properties of metal and the material properties of ceramics. Therefore, the second mixed layer 60 has high adhesion with the second support 70 and has high adhesion with the cathode 50 . As described above, delamination between the second support 70 and the cathode 50 can be suppressed.

In addition, in the fuel cell 100, the oxide ion conductive ceramics 33 is supported on the porous body of the anode 30. In this structure, it is possible to first form the porous body by firing, and then impregnate the porous body with the oxide ion conductive ceramics 33 and fire it at a low temperature. Therefore, even if the oxide ion conductive ceramics 32 and the oxide ion conductive ceramics 33 do not have the same composition, the reaction between the oxides is suppressed. Therefore, the degree of freedom in selecting an oxide suitable for the composite catalyst as the oxide ion conductive ceramics 33 is increased.

Similarly, in the fuel cell 100, the cathode catalyst 53 is supported on the porous body of the cathode 50. In this structure, it is possible to first form the porous body by firing, and then impregnate the cathode catalyst 53 and fire it at a low temperature. Therefore, even if the oxide ion conductive ceramics 52 and the cathode catalyst 53 do not have the same composition, the reaction between the oxides is suppressed. Therefore, the degree of freedom in selecting a preferable oxide for the cathode catalyst 53 is increased.

In addition, among the porosity of the first support 10, the porosity of the first mixed layer 20, and the porosity of the anode 30, there is a relationship of (first support 10>first mixed layer 20>anode 30). It is preferable to be established. A relationship of (second support 70>second mixed layer 60>cathode 50) is established among the porosity of the second support 70, the porosity of the second mixed layer 60, and the porosity of the cathode 50. is preferred. By establishing this relationship, the support can have sufficient gas permeability. In the electrode, having a relatively low porosity provides high electronic conductivity and high oxide ion conductivity while maintaining gas permeability. In the mixed layer, gas permeability is obtained, and a contact area with the support is obtained, so that adhesion with the support is obtained.

Further, it is preferable that the thickness of the first support 10, the thickness of the first mixed layer 20, and the thickness of the anode 30 satisfy the relationship of first support 10>first mixed layer 20>anode 30. , the thickness of the second support 70, the thickness of the second mixed layer 60, and the thickness of the cathode 50, the relationship of second support 70>second mixed layer 60>cathode 50 is preferably established. When these relationships are established, most of the volume (for example, 80% or more) of the entire fuel cell 100 is made of a metal material, so that effects such as rapid heating and cooling and improved mechanical strength such as flexibility can be obtained. .

Since the anode reaction and the cathode reaction are chemical reactions that occur on the surface of the catalyst, it is preferable that the surface area per unit volume of the catalyst is large from the viewpoint of promoting the chemical reaction. For example, the average crystal grain size of the anode catalyst (the oxide ion conductive ceramics 33 and the catalyst metal 34) and the cathode catalyst 53 is preferably 100 nm or less, more preferably 80 nm or less, and 50 nm or less. is more preferred.

If the thicknesses of the anode 30 and the cathode 50, the thicknesses of the first mixed layer 20 and the second mixed layer 60, and the thicknesses of the first support 10 and the second support 70 increase, the fuel cell The structure of the fuel cell 100 approaches an asymmetrical structure, the thermal stress between the upper and lower materials is not canceled, and the fuel cell 100 may warp. Therefore, for example, the thickness of the anode 30 is within ±50% of the thickness of the cathode 50, the thickness of the first mixed layer 20 is within ±50% of the thickness of the second mixed layer 60, and the thickness of the first support 10 is within the second It is preferable that the variation is within ±50% of the thickness of the support 70 .

In order to facilitate the flow of gas during power generation, that is, from the viewpoint of suppressing gas diffusion resistance, the crystal grain size of the metal component of the first support 10 and the second support 70 is set to the first mixed layer 20 and second mixed layer 20 It is preferably larger than the crystal grain size of the metal component of layer 60 . If the crystal grain size is large, the gaps between the particles also become large, making it easier for the gas to pass through. For example, the crystal grain size of the metal component of the first support 10 and the second support 70 is preferably 10 μm or more, more preferably 20 μm or more. In addition, if the crystal grain size of the metal is too large when producing the green sheet, the metal powder will settle during coating, resulting in non-uniform distribution of the material in the thickness direction of the green sheet. From the viewpoint of maintaining the quality of the green sheet, the crystal grain size of the metal component of the first support 10 and the second support 70 is preferably 100 μm or less, preferably 80 μm or less.

Since the catalysts for the anode 30 and cathode 50 are added by an impregnation method, a space for the catalyst is required. From the viewpoint of placing a certain amount of catalyst in the pores to obtain sufficient performance, the porosity of the porous body is preferably 20% or more, and preferably 50% or more, in the cross-sectional area of the anode 30 and the cathode 50. is more preferable.

Since the electrode reaction mainly occurs at the three-phase interface, the thickness of the anode 30 and the cathode 50 is preferably 2 μm or more, more preferably 5 μm or more, more preferably 10 μm, from the viewpoint of ensuring a sufficient three-phase interface. It is more preferable that it is above.

　In order to achieve a high-performance electrode, it is necessary to ensure a certain level of electronic and ionic conductivity in the electrode layer. If the amount of the ion-conducting ceramic material is too large, the electron conductivity in the electrode layer is lowered, and sufficient performance cannot be obtained. On the other hand, if the amount of the electronically conductive ceramics material is too large, the ionic conductivity of the electrode layer is lowered, and sufficient performance cannot be obtained. From the viewpoint of balancing the ion conductivity and electronic conductivity in the electrode layer, both the lower limit and the upper limit are set for the cross-sectional area ratio of the ion-conducting ceramics and the electron-conducting ceramics in the porous bodies of the anode 30 and the cathode 50. It is preferable to provide For example, in the porous bodies of the anode 30 and the cathode 50, the cross-sectional area ratio of the ion-conducting ceramics and the electron-conducting ceramics is preferably 1:3 to 3:1, preferably 1:9 to 9:1. is more preferable.

A method for manufacturing the fuel cell 100 will be described below. FIG. 5 is a diagram illustrating the flow of the manufacturing method of the fuel cell 100. As shown in FIG.

(Process for producing first support material and second support material)
Materials for the support include metal powder (for example, particle size is 10 μm to 100 μm), plasticizer (for example, adjusted to 1 wt % to 6 wt % to adjust the adhesion of the sheet), solvent (toluene, 2-propanol ( IPA), 1-butanol, terpineol, butyl acetate, ethanol, etc. (20 wt% to 30 wt% depending on viscosity), vanishing material (organic matter), binder (PVB, acrylic resin, ethyl cellulose, etc.) are mixed to form a slurry. . A support material is used as a material for forming a support. The volume ratio of the organic component (vanishing material, binder solid content, plasticizer) to the metal powder is, for example, in the range of 1:1 to 20:1, and the amount of the organic component is adjusted according to the porosity.

(Process for producing first mixed layer material and second mixed layer material)
As materials for the mixed layer, ceramic material powder (for example, a particle size of 100 nm to 10 μm) that is a raw material for the

ceramic materials

22 and 62, and small-particle-size metal material powder that is a raw material for the metal materials 21 and 61 (for example, a particle size of 1 μm to 10 μm), solvent (toluene, 2-propanol (IPA), 1-butanol, terpineol, butyl acetate, ethanol, etc., 20 wt% to 30 wt% depending on viscosity), plasticizer (for example, sheet adhesion 1 wt % to 6 wt %), a vanishing material (organic matter), and a binder (PVB, acrylic resin, ethyl cellulose, etc.) are mixed to form a slurry. The volume ratio of the organic component (vanishing material, binder solid content, plasticizer) to the ceramic material powder and the metal material powder is, for example, in the range of 1:1 to 5:1, and the amount of the organic component is adjusted according to the porosity. adjust. Also, the pore size of the voids is controlled by adjusting the particle size of the vanishing material. The ceramic material powder may contain electronically conductive material powder and oxide ion conductive material powder. In this case, the volume ratio of the electron conductive material powder and the oxide ion conductive material powder is preferably in the range of 1:9 to 9:1, for example. Also, even if an electrolyte material such as ScYSZ or GDC is used in place of the electronically conductive material, it is possible to fabricate a cell without peeling of the interface. However, from the viewpoint of reducing the ohmic resistance, it is preferable to mix the electron conductive material and the metal powder.

(Manufacturing process of anode material)
As materials for the anode, ceramic material powder constituting the porous body, solvent (toluene, 2-propanol (IPA), 1-butanol, terpineol, butyl acetate, ethanol, etc., 20 wt% to 30 wt% depending on viscosity), plasticizer An agent (for example, adjusted to 1 wt % to 6 wt % to adjust the adhesion of the sheet), a vanishing material (organic matter), and a binder (PVB, acrylic resin, ethyl cellulose, etc.) are mixed to form a slurry. As the ceramic material powder constituting the porous body, an electronically conductive material powder (for example, a particle size of 100 nm to 10 μm) that is the raw material of the electronically conductive ceramics 31, and an oxide ion conductive material that is the raw material of the oxide ion conductive ceramics 32. A flexible material powder (for example, a particle size of 100 nm to 10 μm) may be used. The volume ratio of the organic component (vanishing material, binder solid content, plasticizer) to the electronic conductive material powder is, for example, in the range of 1:1 to 5:1, and the amount of the organic component is adjusted according to the porosity. Also, the pore size of the voids is controlled by adjusting the particle size of the vanishing material. The volume ratio of the electron conductive material powder and the oxide ion conductive material powder is, for example, in the range of 1:9 to 9:1.

(Manufacturing process of cathode material)
As materials for the cathode, ceramic material powder constituting the porous body, solvent (toluene, 2-propanol (IPA), 1-butanol, terpineol, butyl acetate, ethanol, etc., 20 wt% to 30 wt% depending on viscosity), plasticizer An agent (for example, adjusted to 1 wt % to 6 wt % to adjust the adhesion of the sheet), a vanishing material (organic matter), and a binder (PVB, acrylic resin, ethyl cellulose, etc.) are mixed to form a slurry. As the ceramic material powder constituting the porous body, an electronically conductive material powder (for example, a particle size of 100 nm to 10 μm), which is a raw material of the electronically conductive ceramics 51, and an oxide ion conductive material, which is a raw material of the oxide ion conductive ceramics 52. A flexible material powder (for example, a particle size of 100 nm to 10 μm) may be used. The volume ratio of the organic component (vanishing material, binder solid content, plasticizer) to the electronic conductive material powder is, for example, in the range of 1:1 to 5:1, and the amount of the organic component is adjusted according to the porosity. Also, the pore size of the voids is controlled by adjusting the particle size of the vanishing material. The volume ratio of the electron conductive material powder and the oxide ion conductive material powder is, for example, in the range of 1:9 to 9:1. In addition, when the anode material and the cathode material are common, the anode material may be used as the cathode material.

(Manufacturing process of electrolyte layer material)
As materials for the electrolyte layer, oxide ion conductive material powder (for example, ScYSZ, YSZ, GDC, etc., with a particle size of 10 nm to 1000 nm), solvents (toluene, 2-propanol (IPA), 1-butanol, terpineol , butyl acetate, ethanol, etc., 20 wt% to 30 wt% depending on the viscosity), a plasticizer (for example, adjusted from 1 wt% to 6 wt% to adjust the adhesion of the sheet), and a binder (PVB, acrylic resin, ethyl cellulose, etc.) to form a slurry. The volume ratio of the organic component (binder solid content, plasticizer) to the oxide ion conductive material powder is, for example, in the range of 6:4 to 3:4.

(Baking process)
First, a first support green sheet is produced by coating a PET (polyethylene terephthalate) film with the material for the first support. A first mixed layer green sheet is produced by coating a first mixed layer material on another PET film. An anode green sheet is produced by coating an anode material on another PET film. An electrolyte layer green sheet is produced by coating the electrolyte layer material on another PET film. A cathode green sheet is produced by coating a cathode material on another PET film. A second mixed layer green sheet is produced by coating a second mixed layer material on another PET film. A second support green sheet is produced by coating a second support material on another PET film. For example, a plurality of first support green sheets, one first mixed layer green sheet, one anode green sheet, one electrolyte layer green sheet, one cathode green sheet, and one second mixed layer green sheet. , and a plurality of second support green sheets are laminated in this order, and cut into a predetermined size. After that, it is fired at a temperature range of about 1100° C. to 1300° C. in a reducing atmosphere with an oxygen partial pressure of 10 ⁻²⁰ atm or less. Thereby, a cell comprising the first support 10, the first mixed layer 20, the anode 30 porous body, the solid electrolyte layer 40, the cathode 50 porous body, the second mixed layer 60, and the second support 70 can be obtained. can. The reducing gas flowing into the furnace may be a gas obtained by diluting H ₂ ₍ hydrogen) with a nonflammable gas (Ar (argon), He (helium), N ₂ (nitrogen), etc.). It may be gas. In consideration of safety, it is preferable to set an upper limit up to the explosion limit. For example, in the case of a mixed gas of H ₂ and Ar, the concentration of H ₂ is preferably 4% by volume or less.

(Anode impregnation step)
Next, the porous body of the anode 30 is impregnated with raw materials of the oxide ion conductive ceramics 33 and the catalyst metal 34 . For example, nitrates or chlorides of Zr, Y, Sc, Ce, Gd, and Ni are combined with water or alcohols so that Gd-doped ceria or Sc, Y-doped zirconia and Ni are produced when sintered at a given temperature in a reducing atmosphere. ethanol, 2-propanol, methanol, etc.), impregnated into the porous body of the anode 30, dried, and heat-treated repeatedly.

(Cathode impregnation step)
A cathode catalyst 53 such as _PrOx is then impregnated into the porous body of the cathode 50 . When PrO 2 _x is used as the cathode catalyst 53, for example, nitrate or chloride of Pr is dissolved in water or alcohols (ethanol, 2-propanol, methanol, etc.), impregnated into the porous body of the cathode 50, dried, and heat-treated. is repeated the required number of times. When LSM is used as the cathode catalyst 53, for example, nitrate or chloride of Sr, nitrate or chloride of La, nitrate or chloride of Mn are dissolved in water or alcohols (ethanol, 2-propanol, methanol, etc.). , the half-cell is impregnated, dried, and the heat treatment is repeated a required number of times. When LSC is used as the cathode catalyst 53, for example, nitrate or chloride of Sr, nitrate or chloride of La, nitrate or chloride of Co are dissolved in water or alcohols (ethanol, 2-propanol, methanol, etc.). , the half-cell is impregnated, dried, and the heat treatment is repeated a required number of times.

According to the manufacturing method according to the present embodiment, when firing the anode 30 and the cathode 50, both the electron conductive material and the oxide ion conductive material are used. Structural differences between porous materials are reduced. Also, the first mixed layer 20 is fired on the anode side, and the second mixed layer 60 is fired on the cathode side. Furthermore, the first support 10 is fired on the anode side, and the second support 70 is fired on the cathode side. Thus, the fuel cell 100 has a symmetrical structure with the solid electrolyte layer 40 as the center. As a result, the difference in shrinkage behavior of each layer during the firing process is reduced, and warping is suppressed. For example, the amount of warp T (%) is 3% or less.

In addition, since the structural difference between the porous body of the anode 30 and the porous body of the cathode 50 is reduced, the anode 30 and the cathode 50 can be fired at the same time. As a result, the adhesion of the anode 30 and the cathode 50 to the solid electrolyte layer 40 is improved, film peeling is suppressed, and the ohmic resistance of the fuel cell 100 as a whole is reduced.

Also, since the material for the first mixed layer contains the metallic material and the ceramic material, the first mixed layer 20 after firing contains the metallic material 21 and the ceramic material 22 . Thereby, the first mixed layer 20 has both the material properties of metal and the material properties of ceramics. Therefore, delamination between the first support 10 and the anode 30 can be suppressed during the firing process. Since the second mixed layer material contains the metal material and the ceramic material, the second mixed layer 60 after firing contains the metal material 61 and the ceramic material 62 . Thereby, the second mixed layer 60 has both the material properties of metal and the material properties of ceramics. Therefore, delamination between the second support 70 and the cathode 50 can be suppressed during the firing process.

A relationship of (first support 10>first mixed layer 20>anode 30) is established among the porosity of the first support 10, the porosity of the first mixed layer 20, and the porosity of the anode 30, and The porosity of the second support 70, the porosity of the second mixed layer 60, and the porosity of the cathode 50 are such that the relationship (second support 70>second mixed layer 60>cathode 50) is established. Moreover, it is preferable to adjust the amount of the vanishing material in the support material, the mixed layer material, the anode material, and the cathode material. By establishing this relationship, the support can have sufficient gas permeability. Electrodes are dense and have high oxide ion conductivity. In the mixed layer, gas permeability is obtained, and a contact area with the support is obtained, so that adhesion with the support is obtained.

In addition, in the manufacturing method according to the present embodiment, it is possible to first form the porous body by sintering, and then impregnate the porous body with the composite catalyst and sinter it at a low temperature (for example, 850° C. or lower). Therefore, the reaction between the porous material of the anode 30 and the anode catalyst is suppressed. Moreover, the reaction between the porous body of the cathode 50 and the cathode catalyst is suppressed. Therefore, the degree of freedom in selecting the anode catalyst and the cathode catalyst is increased.

(Second embodiment)
FIG. 6 is a schematic cross-sectional view illustrating the laminated structure of the fuel cell 100a according to the second embodiment. The fuel cell 100a differs from the fuel cell 100 of FIG. 1 in that an insulating member 90 functioning as a sealing member is provided.

The first support 10, the first mixed layer 20, the anode 30, the solid electrolyte layer 40, the cathode 50, the second mixed layer 60, and the second support 70 have substantially the same size (for example, rectangular or square). )have. In addition, the positions of the outer peripheries (side surfaces) of the first support 10, the first mixed layer 20, the anode 30, the solid electrolyte layer 40, the cathode 50, the second mixed layer 60, and the second support 70 are substantially aligned. there is Therefore, the outer peripheries of the first support 10, the first mixed layer 20, the anode 30, the solid electrolyte layer 40, the cathode 50, the second mixed layer 60 and the second support 70 form an outer peripheral surface. This outer peripheral surface is called a cell outer peripheral surface. The outer peripheral surface of the cell is covered with an insulating member 90 . The insulating member 90 is not particularly limited as long as it is made of a material having insulating properties, and is, for example, glass.

Since the outer peripheral surface of the cell is covered with the insulating member 90, when the catalyst is impregnated, it is suppressed from permeating along the outer peripheral surface of the cell to the electrode on the opposite side due to capillary action. For example, the permeation of the anode catalyst to the cathode 50 is suppressed, and the permeation of the cathode catalyst to the anode 30 is suppressed. Thereby, the short circuit between electrodes can be suppressed.

The insulating member 90 preferably extends to the surface (lower surface) of the first support 10 opposite to the first mixed layer 20 . Moreover, the insulating member 90 preferably extends to the surface (upper surface) of the second support 70 opposite to the second mixed layer 60 . By extending the insulating member 90 to at least one of the lower surface of the first support 10 and the upper surface of the second support 70, penetration of the catalyst to the electrode on the opposite side is further suppressed. Become.

Here, the length of one side of the rectangular shape of the first support 10, the first mixed layer 20, the anode 30, the solid electrolyte layer 40, the cathode 50, the second mixed layer 60, and the second support 70 is b. The extension distance of the insulating member 90 with respect to the lower surface of the first support 10 and the extension distance of the insulation member 90 with respect to the upper surface of the second support 70 are referred to as distance a.

If the distance a is too long, the area covered by the insulating member 90 on the lower surface of the first support 10 and the upper surface of the second support 70 will increase, so that the first support 10 and the second support 70 will not be exposed to the catalyst impregnation liquid. The area in contact with the In this case, the effective power generation area ratio decreases. The effective power generation area ratio can be defined as (area of electrode impregnated with catalyst)/(area of entire electrode). Therefore, it is preferable to set an upper limit for the a/b ratio. For example, the a/b ratio is preferably 1/10 or less, more preferably 1/20 or less, and even more preferably 1/50 or less.

It is preferable that the insulating member 90 not only cover the outer peripheral surface of the cell, but also partially intrude from the outer peripheral surface of the cell as illustrated in FIG. In this case, the permeation of the catalyst to the electrode on the opposite side is further suppressed.

FIG. 7 is a diagram illustrating the flow of the manufacturing method of the fuel cell 100a. A different point from the manufacturing method of FIG. 5 is that an insulating member forming step is performed between the baking step and the impregnating step.

FIGS. 8(a) and 8(b) are diagrams for explaining the details of the insulating member forming process. As exemplified in FIG. 8(a), the cell outer peripheral surfaces (four side surfaces) of the cell 200 obtained by the firing step are attached one by one to a container 300 containing, for example, a glass sealing material, and the cell is dipped. Apply sealing material to the outer peripheral surface. The depth of the dip makes it possible to control the coverage of the sealant coating. After that, as illustrated in FIG. 8B, the insulating member 90 can be formed by drying and firing.

In order to suppress penetration of the catalyst into the electrode on the opposite side, for example, it is conceivable to make the area of one electrode smaller than the area of the other electrode. However, in order to form an electrode with a small area, it is necessary to repeatedly print by a construction method such as a slurry build on the laminated body laminated up to the electrolyte layer. If this method is used, there is a problem that the manufacturing process becomes long and the cost rises. On the other hand, the manufacturing method according to the present embodiment eliminates the need for slurry rebuilding, so the cost can be suppressed. Further, in the method of forming an insulating member on the outer peripheral surface of the cell, the above-described distance a can be reduced, so that the effective power generation area ratio can be increased.

A fuel cell was manufactured according to the manufacturing method according to the above embodiment.

(Example 1)
SUS (stainless steel) powder was used as the support material. ScYSZ was used as the electrolyte layer. A LaCrO ₃ -based material was used for the electron-conducting ceramics of the anode, and ScYSZ was used for the oxide ion-conducting ceramics. A LaCrO ₃ -based material was used for the electron-conducting ceramics of the cathode, and ScYSZ was used for the oxide ion-conducting ceramics. A LaCrO ₃ -based material was used as the ceramic material for the mixed layer. SUS was used as the metal material of the mixed layer.

A first support green sheet, a first mixed layer green sheet, an anode green sheet, an electrolyte green sheet, a cathode green sheet, a second mixed layer green sheet, and a second support green sheet are laminated in this order and subjected to a firing process, A single cell with a symmetrical structure was fabricated. The cathode porous body was impregnated with _PrOx as a cathode catalyst. The anode porous body was impregnated with Ni and GDC as an anode catalyst.

When the warp amount of the single cell was evaluated, it was less than 1%. It is considered that this is because of the symmetrical structure.

Next, a single cell power generation evaluation was performed. The single cell was evaluated in a state in which it was sandwiched between interconnectors from above and below. A single cell and an interconnector were connected by laser welding without providing a current collector. As a result of power generation evaluation, each resistance value was separated by impedance measurement. The ohmic resistance of the single cell was 0.5 Ω·cm ² and the reaction resistance was 0.4 Ω·cm ² .

(Example 2)
In Example 2, the cathode porous body was impregnated with LSM. Other conditions were the same as in Example 1.

When the single cell warp amount was evaluated, it was less than 1%. It is considered that this is because of the symmetrical structure.

Next, a single cell power generation evaluation was performed. The single cell was evaluated in a state in which it was sandwiched between interconnectors from above and below. A single cell and an interconnector were connected by laser welding without providing a current collector. As a result of power generation evaluation, each resistance value was separated by impedance measurement. The ohmic resistance of the single cell was 0.3 Ω·cm ² and the reaction resistance was 0.7 Ω·cm ² . It is believed that the difference in ohmic resistance and reaction resistance from Example 1 is due to the difference in the cathode catalyst. From the results of Examples 1 and 2, it can be seen that it is preferable to use LSM from the viewpoint of reducing ohmic resistance, and it is preferable to use _PrOx from the viewpoint of reducing reaction resistance.

(Example 3)
In Example 3, the cathode porous body was impregnated with GDC and LSC. In order to suppress the reaction between ScYSZ and LSC, GDC was first impregnated and then LSC was impregnated. Other conditions were the same as in Example 1.

Next, a single cell power generation evaluation was performed. The single cell was evaluated in a state in which it was sandwiched between interconnectors from above and below. A single cell and an interconnector were connected by laser welding without providing a current collector. As a result of power generation evaluation, each resistance value was separated by impedance measurement. The ohmic resistance of the single cell was 0.3 Ω·cm ² and the reaction resistance was 0.6 Ω·cm ² . It is believed that the difference in ohmic resistance and reaction resistance from Example 1 is due to the difference in the cathode catalyst. From the results of Examples 2 and 3, it can be seen that it is preferable to use LSC from the viewpoint of reducing the reaction resistance.

(Example 4)
The manufacturing conditions for the single cell were the same as in Example 3. When the amount of warpage of the single cell was evaluated, it was less than 1% as in Example 3. It is considered that this is because of the symmetrical structure.

Next, a single cell power generation evaluation was performed. The single cell was evaluated in a state in which it was sandwiched between interconnectors from above and below. On the anode side, the single cell and the interconnector were connected by laser welding without providing a current collector. On the cathode side, no current collector was provided between the single cell and the interconnector, and no laser welding was performed. As a result of power generation evaluation, each resistance value was separated by impedance measurement. The ohmic resistance of the single cell was 0.4 Ω·cm ² and the reaction resistance was 0.6 Ω·cm ² . These results show that it is preferable to use welding to connect the single cells and the interconnectors. This becomes noticeable when stacking a plurality of single cells.

(Comparative example 1)
In Comparative Example 1, an asymmetric structure was adopted without providing a support on the cathode side. Other conditions were the same as in Example 3. When the warp amount of the single cell was evaluated, it was 3%. It is considered that this is because the asymmetric structure made the difference in the coefficient of thermal expansion of each material remarkable.

Next, a single cell power generation evaluation was performed. The single cell was evaluated in a state in which it was sandwiched between interconnectors from above and below. On the anode side, the single cell and the interconnector were connected by laser welding without providing a current collector. Attempts were made to weld the mixed layer on the cathode side to the interconnector, but it was found to be unweldable. It is considered that this is because the ceramic material is mixed in the mixed layer. Therefore, instead of welding on the cathode side, the current collector was installed between the single cell and the interconnector, and evaluated in a sandwiched state. As a result of power generation evaluation, each resistance value was separated by impedance measurement. The ohmic resistance of the cell was 0.7 Ω·cm ² and the reaction resistance was 0.6 Ω·cm ² . Compared with Example 3, the ohmic resistance increased because the cathode side was not connected by welding.

(Comparative example 2)
In Comparative Example 2, a support green sheet, a mixed layer green sheet, an anode green sheet, and an electrolyte green sheet were laminated in this order, and a firing process was performed to produce a half cell. Thereafter, a GDC layer having a thickness of about 700 nm was formed on the solid electrolyte layer by PVD film formation, a cathode was printed using LSC paste, and the layer was fired to complete a single cell. Other conditions were the same as in Example 1.

When evaluating the warpage amount of the single cell, it was 4%. It is considered that this is because the asymmetric structure made the difference in the coefficient of thermal expansion of each material remarkable.

Next, a single cell power generation evaluation was performed. The single cell was evaluated in a state in which it was sandwiched between interconnectors from above and below. On the anode side, the single cell and the interconnector were connected by laser welding without providing a current collector. On the cathode side, instead of welding, the current collector was installed between the unit cell and the interconnector, and the evaluation was performed in a sandwiched state. As a result of power generation evaluation, each resistance value was separated by impedance measurement. The ohmic resistance of the single cell was 0.7 Ω·cm ² and the reaction resistance was 0.6 Ω·cm ² . Compared with Example 3, the ohmic resistance increased because the cathode side was not connected by welding.

(Comparative Example 3)
In Comparative Example 3, an all-ceramic single cell was produced instead of a metal-supported single cell. A mixture of NiO/YSZ was used for the support. A NiO/ScYSZ cermet electrode was used as the anode. A dense layer of ScYSZ was used as the solid electrolyte layer. A GDC layer having a thickness of about 700 nm was formed on the solid electrolyte layer by PVD film formation, a cathode was printed using LSC paste, and a single cell was completed by firing. No mixed layer was provided.

Next, a single cell power generation evaluation was performed. The single cell was evaluated in a state in which it was sandwiched between interconnectors from above and below. On the anode side, the single cell and the interconnector were connected by laser welding without providing a current collector. On the cathode side, instead of welding, the current collector was installed between the unit cell and the interconnector, and the evaluation was performed in a sandwiched state. As a result of power generation evaluation, each resistance value was separated by impedance measurement. The ohmic resistance of the single cell was 0.9 Ω·cm ² and the reaction resistance was 0.6 Ω·cm ² . Compared to Example 3, an increase in ohmic resistance was observed because none of the electrodes were connected by welding.

(Comparative Example 4)
In Comparative Example 4, LSM paste was printed instead of LSC paste for the cathode. Other conditions were the same as in Comparative Example 3.

Next, a single cell power generation evaluation was performed. The single cell was evaluated in a state in which it was sandwiched between interconnectors from above and below. On the anode side, the single cell and the interconnector were connected by laser welding without providing a current collector. On the cathode side, instead of welding, the current collector was installed between the unit cell and the interconnector, and the evaluation was performed in a sandwiched state. As a result of power generation evaluation, each resistance value was separated by impedance measurement. The ohmic resistance of the single cell was 0.9 Ω·cm ² and the reaction resistance was 1.2 Ω·cm ² . Compared to Example 3, an increase in ohmic resistance was observed because none of the electrodes were connected by welding. Moreover, compared with Comparative Example 3, an increase in reaction resistance was observed. It is believed that this is because the catalytic activity of LSM is lower than that of LSC.

The results of Examples 1-4 and Comparative Examples 1-4 are shown in Tables 1 and 2.

(Example 5)
A single cell having a symmetrical structure was produced by carrying out the firing process in the same manner as in Example 1. The size of the single cell in plan view was 100 mm×100 mm. An insulating member was applied to the outer peripheral surface of the cell by dipping. The dip depth was set to 1 mm. The cathode porous body was impregnated with LSM as a cathode catalyst for an area of 98 mm×98 mm. The porous body of the anode was impregnated with Ni and GDC as an anode catalyst for an area of 98 mm×98 mm. The effective power generation area utilization rate was (98 mm×98 mm)/(100 mm×100 mm)=96%.

When the warp amount of the single cell was evaluated, it was less than 1%. It is considered that this is because of the symmetrical structure. When the catalyst was impregnated, the impregnating liquid did not seep into the electrode on the opposite side. It is considered that this is because the insulating member is provided.

Next, a single cell power generation evaluation was performed. The single cell was evaluated in a state in which it was sandwiched between interconnectors from above and below. A single cell and an interconnector were connected by laser welding without providing a current collector. As a result of power generation evaluation, each resistance value was separated by impedance measurement. The ohmic resistance of the single cell was 0.3 Ω·cm ² and the reaction resistance was 0.7 Ω·cm ² . The current that flowed when the terminal voltage was 0.9V was 19.1A.

(Example 6)
A single cell having a symmetrical structure was produced by carrying out the firing process in the same manner as in Example 1. The size of the single cell in plan view was 100 mm×100 mm. An insulating member was applied to the outer peripheral surface of the cell by dipping. The dip depth was set to 2 mm. The cathode porous body was impregnated with LSM as a cathode catalyst for an area of 96 mm×96 mm. The anode porous body was impregnated with Ni and GDC as an anode catalyst for an area of 96 mm×96 mm. The effective power generation area utilization rate was (96 mm×96 mm)/(100 mm×100 mm)=92%.

Next, a single cell power generation evaluation was performed. The single cell was evaluated in a state in which it was sandwiched between interconnectors from above and below. A single cell and an interconnector were connected by laser welding without providing a current collector. As a result of power generation evaluation, each resistance value was separated by impedance measurement. The ohmic resistance of the single cell was 0.3 Ω·cm ² and the reaction resistance was 0.7 Ω·cm ² . The current that flowed when the terminal voltage was 0.9V was 18.3A. From the results of comparison between Example 5 and Example 6, it can be seen that the higher the effective power generation area utilization rate, the larger the current.

(Example 7)
A first support green sheet, a first mixed layer green sheet, an anode green sheet, and an electrolyte green sheet were laminated in this order to obtain a laminate. Next, on the electrolyte green sheet, a cathode layer is printed in an area smaller than that of the laminate by 2 to 3 mm from the outer periphery and dried, a mixed layer is printed and dried, and a second support layer is printed. A unit cell having a symmetrical structure was produced by carrying out slurry build-up to dry and then co-firing. The size of the single cell in plan view was 100 mm×100 mm. The area on the cathode side was 96 mm x 96 mm = 9216 ^mm2 . No insulating member was formed on the outer peripheral surface of the cell. The cathode porous body was impregnated with LSM as a cathode catalyst for an area of 96 mm×96 mm. The anode porous body was impregnated with Ni and GDC as an anode catalyst for an area of 96 mm×96 mm. The effective power generation area utilization rate was (96 mm×96 mm)/(100 mm×100 mm)=92%.

When the warp amount of the single cell was evaluated, it was less than 1%. It is considered that this is because of the symmetrical structure. When the catalyst was impregnated, the impregnating liquid did not seep into the electrode on the opposite side. It is considered that this is because the cathode was formed in a small area by carrying out the slurry rebuild.

Next, a single cell power generation evaluation was performed. The single cell was evaluated in a state in which it was sandwiched between interconnectors from above and below. A single cell and an interconnector were connected by laser welding without providing a current collector. As a result of power generation evaluation, each resistance value was separated by impedance measurement. The ohmic resistance of the single cell was 0.3 Ω·cm ² and the reaction resistance was 0.7 Ω·cm ² . The current that flowed when the terminal voltage was 0.9V was 18.3A. From the comparison results of Example 6 and Example 7, since the effective power generation area ratio is the same, the power generation characteristics are almost the same. Since Example 6 does not use a slurry build, it is advantageous in terms of cost.

(Example 8)
A single cell having a symmetrical structure was produced by carrying out the firing process in the same manner as in Example 1. The size of the single cell in plan view was 100 mm×100 mm. No insulating member was formed on the outer peripheral surface of the cell. When the catalyst was impregnated, a space of 10 mm was kept from the outer circumference so that the impregnating liquid would not permeate the electrode on the opposite side. The anode porous body was impregnated with Ni and GDC for an area of 80 mm×80 mm. The cathode porous body was impregnated with LSM over an area of 80 mm×80 mm. The effective power generation area utilization rate was (80 mm×80 mm)/(100 mm×100 mm)=64%.

When the warp amount of the single cell was evaluated, it was less than 1%. It is considered that this is because of the symmetrical structure. When the catalyst was impregnated, the impregnating liquid did not seep into the electrode on the opposite side. It is believed that this is because the area impregnated with the catalyst was reduced.

Next, a single cell power generation evaluation was performed. The single cell was evaluated in a state in which it was sandwiched between interconnectors from above and below. A single cell and an interconnector were connected by laser welding without providing a current collector. As a result of power generation evaluation, each resistance value was separated by impedance measurement. The ohmic resistance of the single cell was 0.3 Ω·cm ² and the reaction resistance was 0.7 Ω·cm ² . The current that flowed when the terminal voltage was 0.9V was 12.7A. From the results of comparison between Example 5 and Example 8, it can be seen that the higher the effective power generation area utilization rate, the larger the current.

(Example 9)
A single cell having a symmetrical structure was produced by carrying out the firing process in the same manner as in Example 1. The size of the single cell in plan view was 100 mm×100 mm. No insulating member was formed on the outer peripheral surface of the cell. When impregnating the catalyst, a space of 2 mm was kept from the outer periphery so that the impregnating liquid would not permeate the electrode on the opposite side. The anode porous body was impregnated with Ni and GDC for an area of 96 mm×96 mm. The cathode porous body was impregnated with LSM over an area of 96 mm x 96 mm.

　When impregnating with the catalyst, the impregnating liquid seemed to seep into the electrode on the opposite side, so power generation evaluation was not performed.

(Comparative Example 5)
In Comparative Example 5, a support green sheet, a mixed layer green sheet, an anode green sheet, and an electrolyte green sheet were laminated in this order, followed by firing to produce a half cell. No insulating member was formed on the outer peripheral surface of the cell. The size of the half-cell in plan view was 100 mm×100 mm. The anode porous body was impregnated with Ni and GDC for an area of 96 mm×96 mm. After that, LSM was printed on an area of 96 mm×96 mm on the solid electrolyte layer and baked at a temperature of 900° C. or lower.

Next, a single cell power generation evaluation was performed. The single cell was evaluated in a state in which it was sandwiched between interconnectors from above and below. On the anode side, the single cell and the interconnector were connected by laser welding without providing a current collector. On the cathode side, instead of welding, the current collector was installed between the unit cell and the interconnector, and the evaluation was performed in a sandwiched state. As a result of power generation evaluation, each resistance value was separated by impedance measurement. The ohmic resistance of the single cell was 0.7 Ω·cm ² and the reaction resistance was 0.7 Ω·cm ² . The current that flowed when the terminal voltage was 0.9V was 13.2A. Although the effective power generation area was the same as that of Example 6, the current obtained by power generation decreased by the amount corresponding to the increase in ohmic resistance.

The results of Examples 5-9 and Comparative Example 5 are shown in Tables 3 and 4.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations can be made within the scope of the gist of the present invention described in the scope of claims. Change is possible.

Claims

a solid electrolyte layer containing a solid oxide having oxide ion conductivity;
an anode provided on the first surface of the solid electrolyte layer, having a porous body containing electronically conductive ceramics and oxide ion conductive ceramics, and having an anode catalyst in the porous body;
a first mixed layer provided on the surface of the anode opposite to the solid electrolyte layer and having a structure in which a metal material and a ceramic material are mixed;
a first support provided on the surface of the first mixed layer opposite to the solid electrolyte layer and containing a metal as a main component;
a cathode provided on the second surface of the solid electrolyte layer, having a porous body containing electronically conductive ceramics and oxide ion conductive ceramics, and having a cathode catalyst in the porous body;
a second mixed layer provided on the surface of the cathode opposite to the solid electrolyte layer and having a structure in which a metal material and a ceramic material are mixed;
A solid oxide fuel cell, comprising: a second support which is provided on a surface of the second mixed layer opposite to the solid electrolyte layer and is mainly composed of a metal.
The solid oxide fuel cell according to claim 1, characterized in that the amount of warpage of the solid oxide fuel cell is less than 3%.
2. An insulating member covering outer peripheries of said first support, said first mixed layer, said anode, said solid electrolyte layer, said cathode, said second mixed layer and said second support. Or the solid oxide fuel cell according to claim 2.
The solid oxide fuel cell has a substantially rectangular shape in plan view,
The insulating member extends to the surface of the first support opposite to the first mixed layer and to the surface of the second support opposite to the second mixed layer, and the distance of the extension is 4. The solid oxide according to claim 3, wherein a/b is 1/10 or less, where a is the distance and b is the length of one side of the solid oxide fuel cell. Physical fuel cell.
The solid oxide fuel cell according to claim 3 or 4, wherein the insulating member is glass.
The insulating member extends inward from outer peripheries of the first support, the first mixed layer, the anode, the cathode, the second mixed layer and the second support. The solid oxide fuel cell according to any one of Claims 3 to 5.
the anode catalyst is Ni and GDC;
7. The solid oxide fuel cell according to any one of claims 1 to 6, wherein the cathode catalyst contains at least one of PrOx , LSM, LSC and GDC.
The solid oxide fuel cell according to any one of claims 1 to 7, wherein each of the anode catalyst and the cathode catalyst has an average particle size of 100 nm or less.
Among the porosity of the first support, the porosity of the first mixed layer, and the porosity of the anode, a relationship of the first support > the first mixed layer > the anode is established, and
A relationship of the second support > the second mixed layer > the cathode is established among the porosity of the second support, the porosity of the second mixed layer, and the porosity of the cathode. 9. The solid oxide fuel cell according to any one of claims 1 to 8.
A relationship of the first support > the first mixed layer > the anode is established between the thickness of the first support, the thickness of the first mixed layer, and the thickness of the anode, and
The thickness of the second support, the thickness of the second mixed layer, and the thickness of the cathode satisfy the relationship of second support>second mixed layer>cathode. The solid oxide fuel cell according to any one of claims 1 to 9.
2. The crystal grain size of the metal component of the first support and the second support is larger than the crystal grain size of the metal component of the first mixed layer and the second mixed layer. 11. The solid oxide fuel cell according to claim 10.
The solid oxide fuel cell according to any one of claims 1 to 11, wherein the porous body has a porosity of 20% or more in the cross-sectional areas of the anode and the cathode.
The solid oxide fuel cell according to any one of claims 1 to 12, characterized in that the anode and the cathode have a thickness of 2 µm or more.
14. Any one of claims 1 to 13, wherein in the porous bodies of the anode and the cathode, the cross-sectional area ratio of the ion-conducting ceramics and the electron-conducting ceramics is 1:9 to 9:1. 1. The solid oxide fuel cell according to claim 1.
On both sides of an electrolyte green sheet containing a solid oxide material powder having oxide ion conductivity, an electrode green sheet containing an electronically conductive ceramics material powder and an oxide ion conductive ceramics material powder, a ceramic material powder and a metal material powder A step of firing a laminate in which a mixed layer green sheet containing the metal powder and a support green sheet containing the metal powder are laminated;
and impregnating a porous body obtained by firing the electrode green sheet with a catalyst.
Before the step of impregnating with the catalyst, a step of covering the support obtained by firing the support green sheet, the mixed layer obtained by firing the mixed layer green sheet, and the outer periphery of the porous body with an insulating member. 16. The method for manufacturing a solid oxide fuel cell according to claim 15, characterized in that: