JP6258882B2 - Green sheet for solid oxide fuel cell and method for producing the same - Google Patents

Description

  The present invention relates to a green sheet used for forming a solid oxide fuel cell and a method for producing the same.

Solid oxide fuel cells (hereinafter sometimes referred to simply as “SOFC”) have high power generation efficiency among various types of fuel cells and can use various fuels. It is being developed as a next-generation power generator with less environmental impact.
An SOFC single cell is essentially composed of a dense layered solid electrolyte made of oxygen ion conductor, and a porous structure air electrode (cathode) is formed on one side of the solid electrolyte, A fuel electrode (anode) having a porous structure is formed on the surface. Among these, anode-supported SOFCs in which a solid electrolyte layer and a cathode layer are sequentially formed on an anode support layer are widely used.

  In typical production of this anode-supported SOFC, first, a slurry-like composition (including paste-like and ink-like, in which the conductive powder is dispersed in a liquid medium, the same applies hereinafter) is prepared. The composition is formed into a sheet having a thickness of about 100 μm by the doctor blade method or the like, and a plurality of these are laminated and dried, so that the anode support layer has a relatively thick thickness (for example, a thickness of about 300 μm to 1500 μm). The green sheet is formed. Then, a SOFC is obtained by sequentially forming and firing a solid electrolyte layer and a cathode layer (both having a thickness of about 20 μm to 50 μm) on the green sheet for the anode support layer. On the other hand, there is also known a method for producing SOFC with reduced energy and cost by omitting the drying step without using a slurry-like composition. For example, Patent Documents 1 to 3 disclose that an SOFC is produced by roll forming after the conductive powder and the binder are granulated as they are or after granulation.

JP 2004-152773 A JP 2012-146579 A JP 2014-135135 A

  By the way, in recent years, as part of improving the performance of SOFC, the solid electrolyte layer and the like have been increased in area and thickness. In general, since the electrical resistance of SOFC increases in proportion to the thickness of each layer, it is possible to realize an SOFC with better power generation performance by making the solid electrolyte layer thinner (for example, 10 μm or less). On the other hand, the SOFC in which the anode support layer is formed by the doctor blade method has a new problem that a through-hole penetrating in the thickness direction is easily formed in the electrolyte layer. In addition, although the method of roll forming the granulated product of the conductive powder shown in Patent Document 3 described above makes it possible to produce an SOFC with excellent power generation performance, its quality is likely to vary and is stable. Therefore, there is a problem that it is difficult to obtain a SOFC with good power generation performance.

  The present invention has been made in view of these circumstances, and an object of the present invention is to provide an SOFC that can hardly produce defects such as through holes and that can stably manufacture an SOFC having excellent power generation performance and high reliability. Is to provide a green sheet. Moreover, it is providing the SOFC manufactured using this green sheet.

In order to achieve the above object, the present invention provides a method for producing a green sheet used for forming a solid oxide fuel cell. This manufacturing method is characterized by including the following steps.
(1) Preparing a raw material mixture containing at least a conductive material and a first binder. Here, the first binder is an acrylic polymer compound.
(2) Forming the green sheet for an anode support layer by roll-forming the raw material mixture.
(3) A solid electrolyte layer green sheet including at least an oxide ion conductor and a second binder is formed on the surface of the anode support layer green sheet.

  When a green sheet for anode support layer is formed by a known doctor blade method or the like and a plurality of sheets are joined together, defects such as through-holes and cracks are generated by firing in the solid electrolyte layer green sheet formed on the upper surface Could occur. According to the study by the present inventors, these through-holes and cracks have been reduced in thickness (for example, 10 μm or less) in the solid electrolyte layer, which has not been a problem until now if the solid electrolyte layer is relatively thick. It was thought that it progressed to a through-hole and a crack. In addition, when a green sheet for an anode support layer is formed by a known doctor blade method or the like, a relatively thin green sheet sheet is overlapped and bonded, so that a gap is formed at the bonding interface or partial peeling occurs between the layers. It was. And the gas contained in such a space | gap at the time of baking acquired the knowledge that the partial peeling part between layers preferentially gathered locally, and could break through a solid electrolyte layer.

  On the other hand, according to the roll forming method, for example, a relatively thick green sheet for an anode support layer of about 100 μm to 1500 μm is more isotropic at once (for example, suppressing variations in composition and porosity in the thickness direction, (Homogeneously). According to further studies by the present inventors, in the method disclosed in the above-mentioned document 3, the green sheet is stored before firing, and after production for a long time (for example, at room temperature for 72 hours or more, or at a high temperature of about 80 ° C.). It has been found that variation in the power generation performance of the SOFC obtained by firing can be observed when 10 hours or more) have elapsed. Accordingly, the present inventors use an acrylic polymer compound instead of the ether polymer compound as the first binder used in the anode support layer green sheet. As a result, the quality stability during storage of the green sheet is enhanced, and even if the SOFC is manufactured after a long time has elapsed from the manufacture, the occurrence of variations in quality such as power generation performance is suppressed. Therefore, according to the green sheet manufacturing method disclosed herein, inconvenience (formation of through holes, variation in quality, etc.) associated with thinning of the solid electrolyte layer is suitably suppressed, and firing is performed at a desired timing. A green sheet for SOFC that can be provided is provided.

In the present specification, the “green sheet” refers to an unfired sheet made of a ceramic raw material prepared when a ceramic sheet (in this case, an anode support layer, a solid electrolyte layer, a reaction suppression layer, and a cathode layer) is prepared. Say. The green sheet includes, in addition to a complete unfired sheet, for example, a sheet dried at a temperature of 100 ° C. or lower (dry sheet), or a sheet preliminarily fired at a temperature of 200 ° C. or lower (temporary fired sheet). To do.
The types of binders contained in the green sheet such as the anode support layer green sheet include, for example, pyrolysis gas chromatography-mass spectrometry (GC-MS) and electron probe microanalysis (EPMA). ). More specifically, a sample for measurement is collected from each of the green sheet for anode support layer and the green sheet for solid electrolyte layer, and the type of binder is specified by introducing this measurement sample into pyrolysis GC-MS and analyzing it. Can do.

  In a preferred embodiment of the production method disclosed herein, the acrylic polymer compound preferably has a glass transition temperature of −100 ° C. or higher and 10 ° C. or lower. By using such an acrylic polymer compound as a binder, quality stability during storage can be further enhanced.

  In a preferred embodiment of the manufacturing method disclosed herein, the green sheet for the solid electrolyte layer is formed by a printing method or a doctor blade method. According to these methods, a dense green sheet for a solid electrolyte layer is formed directly on the green sheet for an anode support layer (eg, an average thickness of 20 μm or less, preferably an average thickness of 10 μm or less). can do. Moreover, in the manufacturing method disclosed here, there are few inconveniences such as through holes and delamination, and an anode support layer green sheet having excellent surface flatness is formed. Therefore, even when the green sheet for a solid electrolyte layer that is thinned by a printing molding method or a doctor blade method is formed, it is preferable because generation of defects and the like due to firing can be suitably suppressed.

In a preferred embodiment of the production method disclosed herein, the green sheet for an anode support layer is preferably formed so that the organic matter content is 10% by mass or less. The green sheet thus obtained is less likely to be warped or deformed in the anode support layer after firing, and it is also possible to suppress the occurrence of defects in the thin solid electrolyte layer due to organic matter burning out during firing. can do. Therefore, it is possible to realize an SOFC excellent in interfacial bonding with the anode support layer without causing defects such as through holes in the solid electrolyte layer.
In addition, organic substance content rate can be measured in the following procedures, for example by differential thermal-thermogravimetric simultaneous measurement (Thermogravimetry-Differential Thermal Analysis: TG-DTA). Specifically, a green sheet for an anode support layer as a measurement sample is collected from the green sheet, and the measurement sample is heated to 500 ° C., for example, in an air atmosphere. For example, the organic matter content can be calculated based on a weight change (weight reduction amount) in a temperature range of 25 ° C. to 500 ° C.

  In a preferred embodiment of the production method disclosed herein, the green sheet for an anode support layer is preferably formed so as to have a single layer structure having an average thickness of 100 μm to 1500 μm. By setting the green sheet for the anode support layer to such a thickness, an SOFC excellent in strength and durability can be realized while realizing improvement in power generation performance by thinning the solid electrolyte layer. In addition, the number of bonding interfaces included in the entire green sheet is higher than that of a green sheet for an anode support layer having a multilayer structure in which a plurality of sheets of about 100 μm, for example, are stacked and bonded by adopting a single layer structure. And the resistance when the SOFC is manufactured can be kept low. This is also preferable from the viewpoint of work efficiency and manufacturing cost. Therefore, an SOFC with higher reliability and durability can be realized more easily and at a lower cost than conventional ones.

  Whether or not the anode support layer green sheet has a single-layer structure can be grasped by, for example, scanning electron microscope (SEM) observation according to the following procedure. Specifically, for example, first, a cross section of the green sheet is formed by cross section polisher processing, and this polished cross section is observed with an SEM. Here, it is possible to confirm whether or not the anode support layer green sheet has a single layer structure by observing the structure of the anode support layer green sheet. Further, it may be determined whether or not the anode support layer green sheet has a single-layer structure in consideration of the number of constituent layers (the number of sheets) of the entire green sheet and the thickness of each layer.

  In the manufacturing method disclosed herein, the second binder preferably includes at least one of polyvinyl butyral and ethyl cellulose. By using such a second binder and solvent, the interfacial adhesion between the green sheet for anode support layer and the green sheet for solid electrolyte layer can be further enhanced. Generation | occurrence | production can be suppressed more reliably.

In a preferred embodiment of the production method disclosed herein, the roll forming method includes, for example, supplying a raw material mixture (typically almost powdery) between a pair of rolls and passing between the rolls. It may be a method of compression molding. And this roll forming method has the following conditions;
(1) adjusting the temperature of the pair of rolls to be higher than the softening temperature of the first binder;
(2) adjusting the distance between the pair of rolls to be 100 μm or more and 1500 μm or less;
(3) The roll linear pressure is set to 0.1 kN / cm or more and 30 kN / cm or less; and (4) The molding speed is set to 0.1 m / min or more and 20 m / min or less;
Are preferably included. According to such an embodiment, it is possible to form a green sheet for an anode support layer that is less likely to cause inconveniences such as warping and deformation in subsequent firing, and is excellent in isotropy and homogeneity.

  In a preferred embodiment of the production method disclosed herein, the method further includes forming a green sheet for reaction inhibition layer containing at least cerium oxide on the surface of the green sheet for solid electrolyte layer. By forming the green sheet for the reaction inhibition layer, when the SOFC is produced, the interface between the solid electrolyte layer and the cathode layer is further stabilized, and the solid phase reaction can be suppressed. Therefore, according to this green sheet, an SOFC that can stably exhibit high performance over a long period of time can be easily produced.

In another aspect, the technology disclosed herein provides a green sheet that is used to form SOFC. The green sheet includes at least an anode support layer green sheet and a solid electrolyte layer green sheet laminated on the anode support layer green sheet. The anode support layer green sheet includes at least a conductive material and a first binder, and has a single-layer structure with an average thickness of 100 μm to 1500 μm. Here, the first binder is an acrylic polymer compound. The solid electrolyte layer green sheet includes at least an oxide ion conductor and a second binder.
With such a configuration, the bondability at the interface between the anode support layer green sheet and the solid electrolyte layer green sheet can be kept good, and the occurrence of interface peeling or the like can be more suitably suppressed. Further, the green sheet for an anode support layer using an acrylic polymer compound as the first binder can be excellent in mechanical strength and durability and excellent in property stability with respect to storage. Therefore, according to the green sheet disclosed herein, excellent power generation performance (high output density) and reliability (durability) even after long-term storage (for example, 3 days or more, particularly 1 week or more) Can be manufactured at a high level.

  About the preferable one aspect | mode of the green sheet for SOFC formation disclosed here, the organic substance content rate of the said green sheet for anode support layers is 10 mass% or less. The green sheet thus obtained is less likely to be warped or deformed in the anode support layer after firing, and it is also possible to suppress the occurrence of defects in the thin solid electrolyte layer due to organic matter burning out during firing. can do. Therefore, it is possible to realize an SOFC excellent in interfacial bonding with the anode support layer without causing defects such as through holes in the solid electrolyte layer.

  About the preferable one aspect | mode of the green sheet for SOFC formation disclosed here, the said 2nd binder contains at least 1 of polyvinyl butyral and ethyl cellulose. These binders are preferable because the adhesion of the solid electrolyte layer green sheet to the anode support layer green sheet can be further improved, and the occurrence of cracks, interfacial peeling, and the like can be suppressed in subsequent firing.

  A preferred embodiment of the green sheet for SOFC formation disclosed herein is characterized in that a green sheet for a reaction inhibiting layer containing at least cerium oxide is provided on the surface of the green sheet for solid electrolyte layer. By forming the green sheet for the reaction inhibition layer, the interface between the solid electrolyte layer and the cathode layer is further stabilized during firing or SOFC operation, and the mutual solid-state reaction can be suppressed. Therefore, according to this green sheet, an SOFC that can stably exhibit high performance over a long period of time can be easily produced.

  In addition, the technology disclosed herein provides a solid oxide fuel cell including a laminate obtained by firing the green sheet. As described above, even when the solid electrolyte layer green sheet is formed thinner than before, the above-mentioned green sheet is uniform in each layer and the generation of voids and defects is suppressed, and good bonding properties are maintained. obtain. Therefore, the SOFC formed using this green sheet can exhibit high power generation performance. In addition, since the bonding strength between the fired anode support layer and the solid electrolyte layer is high, it is difficult to cause interface peeling even during SOFC operation, and high power generation performance can be stably exhibited over a long period of time. In other words, the SOFC disclosed herein can have high performance and high durability.

It is the figure which showed typically a mode that the green sheet was manufactured by roll forming. FIG. 2 is a cross-sectional view schematically showing a green sheet according to an embodiment, where (a) is a SOFC green sheet composed of an anode support layer green sheet and a solid electrolyte layer green sheet, and (b) is a reaction inhibition layer. Each of the SOFC green sheets provided with the green sheet is shown. 1 is a cross-sectional view schematically showing a power generation system including an anode-supported SOFC according to an embodiment.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings as appropriate. Note that matters other than the matters specifically mentioned in the present specification and necessary for the implementation of the present invention (for example, the configuration and manufacturing method of the power generation system) can be obtained by those skilled in the art based on the prior art in this field. It can be grasped as a design matter. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field. In the following drawings, members / parts having the same action are described with the same reference numerals, and redundant descriptions may be omitted or simplified. In addition, the dimensional relationships (length, width, thickness, etc.) in each drawing do not reflect actual dimensional relationships.

  2A and 2B are SOFC green sheets 110G and 120G provided by the present invention. The green sheet 110G of FIG. 2A is provided with a solid electrolyte layer green sheet 20G on the surface of a relatively thick anode support layer green sheet 10G. In addition, the green sheet 120G of FIG. 2B is further provided with a reaction inhibiting layer green sheet 30G on the surface of the green sheet 110G on the solid electrolyte layer green sheet 20G side. Although the manufacturing method of these SOFC green sheets is not particularly limited, it can be suitably manufactured by the SOFC green sheet manufacturing method disclosed herein. Hereinafter, this manufacturing method will be described. That is, this manufacturing method is essentially characterized by including the following steps.

(1) Preparing a raw material mixture containing at least a conductive material and a first binder. Here, the first binder is an acrylic polymer compound.
(2) Form the anode support layer green sheet 10G by roll forming the raw material mixture.
(3) A solid electrolyte layer green sheet 20G including at least an oxide ion conductor and a second binder is formed on the surface of the anode support layer green sheet 10G.
In a preferred embodiment, the following steps are further included after the above step (3).
(4) The reaction inhibiting layer green sheet 30G containing at least cerium oxide and a binder is formed on the surface of the solid electrolyte layer green sheet 20G.

1. Preparation of Raw Material Mixture In the manufacturing method disclosed herein, first, a raw material mixture for forming the anode support layer green sheet 10G as shown in FIGS. 2 (a) and (b) is prepared. This raw material mixture contains at least a conductive material and a binder. Typically, the conductive material and the binder are mixed in a substantially uniform dispersion state to constitute a raw material mixture.

As the conductive material, one or two or more kinds of substances that exhibit conductivity and have an electrocatalytic action (catalytic activity) that can be conventionally used for forming the anode layer of SOFC are used without particular limitation. it can. Specifically, titanium (Ti), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), strontium (Sr), zirconium (Zr), ruthenium (Ru), palladium (Pd), Metal materials such as osmium (Os), iridium (Ir), platinum (Pt), lanthanum (La), gold (Au), and metal oxides thereof can be used. Any of these may be used alone or in combination of two or more. Among them, Co, Ni, Zr, Ru, cobalt oxide (CoO, Co ₂ O ₃ , Co ₃ O ₄ ), nickel oxide (NiO, Ni ₂ O ₃ , Ni ₃ O ₄ ), zirconium oxide (ZrO ₂ ), Ruthenium oxide (RuO ₂ ) or the like can be preferably used. In particular, Ni can be a particularly suitable metal species because it is relatively cheaper than other metals and exhibits high reaction activity (has high catalytic ability). Therefore, in the manufacturing method disclosed herein, a nickel-containing material (for example, nickel or nickel oxide) can be particularly preferably used as the conductive material.

  As the conductive material, for example, a composite material obtained by mixing the above-described metal material and / or metal oxide material (hereinafter simply referred to as “metal-based material”) with another material may be used. For example, a composite material in which the metal-based material and a material for forming the solid electrolyte layer 20 described below (typically an oxide ion conductor) are mixed at an arbitrary ratio can be used. Preferable examples include nickel-based materials (for example, NiO) and, for example, yttria stabilized zirconia (YSZ), calcia stabilized zirconia (CSZ), scandia stabilized zirconia (ScSZ), and the like. And a mixture or cermet with the stabilized zirconia. Any one of these may be mixed with the metal material, or two or more may be mixed.

  By including the constituent material (oxide ion conductor) of the solid electrolyte layer in the anode support layer green sheet 10G, not only the consistency (familiarity) between the green sheets but also the anode support layer during firing The consistency with the solid electrolyte layer (for example, the harmony of thermal expansion coefficient) can be improved, and the bondability (adhesion) between the anode support layer and the solid electrolyte layer during operation of the SOFC can be improved. . Therefore, even in the operation of the SOFC obtained thereafter from the formation of the green sheet, problems such as interfacial peeling can be suppressed. As a result, an SOFC having excellent durability and reliability can be realized. The mixing ratio of the metal-based material and the solid electrolyte layer forming material is not particularly limited. For example, the mass ratio may be 90:10 to 40:60 (preferably 80:20 to 50:50). it can.

Although the property of the conductive material is not particularly limited, for example, a powdery (particulate) material having an average particle diameter of about 0.01 μm to 5 μm (typically 0.1 μm to 2 μm) can be preferably used. Moreover, when preparing and using the above cermets, it is preferable to mix and use materials having substantially the same average particle diameter. For example, it is preferable to use a nickel-based material having an average particle size of about 0.1 μm to 5 μm and a stabilized zirconia having an average particle size of about 0.1 μm to 5 μm in the above ratio. Thereby, a more uniform green sheet for an anode support layer can be realized. In the present specification, the “average particle size” means a particle size corresponding to 50% cumulative from the fine particle side in a volume-based particle size distribution measured by a particle size distribution measurement based on a general laser diffraction / light scattering method. (D ₅₀ particle diameter, also called median diameter). Such adjustment of the particle diameter can be performed by a conventionally known pulverization process, sieving, classification or the like.

  As the first binder, one having thermoplasticity and capable of being evaporated and removed by a binder removal process (typically, heat baking at 200 ° C. or higher) can be used. Among these, an acrylic polymer compound or a compound mainly composed of the acrylic polymer compound can be preferably used. The acrylic polymer compound can firmly bond the particles of the conductive material with a relatively small addition amount. For this reason, the organic substance content rate of the green sheet 10G for anode support layers can be reduced, and generation | occurrence | production of the curvature and void at the time of subsequent baking can be suppressed. In addition, adhesion (affinity) between the green sheet for anode support layer 10G and the green sheet for solid electrolyte layer 20G can be improved, and a green sheet that hardly causes interfacial peeling can be realized. Furthermore, since the acrylic polymer compound is excellent in water resistance and chemical resistance, the shape of the green sheet for the anode support layer can be stably maintained over a long period of time. In particular, even when stored in a high temperature environment (for example, 50 ° C. or more, particularly 80 ° C. or more) for a long period (for example, 3 days or more, more than 1 week, particularly 2 weeks or more), these binder components are hardly volatilized. Stable properties can be maintained. Therefore, it is excellent in reliability and durability that can be used at any timing without worrying about the period until the manufacture of SOFC (which may be a half cell described later) (that is, firing the green sheets 110G and 120G). A green sheet can be suitably formed.

  As described above, when an ether-based polymer compound is used as the binder constituting the anode support layer green sheet 10G, the interfacial bondability with the solid electrolyte layer green sheet 20G is good, but the stability to storage is high. Has the disadvantage of being low. In particular, the properties of the green sheets 110G and 120G were easily changed by storage in a high temperature environment. Although the detailed cause is not clear, the present inventors believe that the change in properties is due to the volatilization of the ether polymer compound during storage. In the present invention, as the binder constituting the anode support layer green sheet 10G, there are several examples that exhibit interfacial bonding properties to the solid electrolyte layer green sheet 20G equivalent to the ether polymer compound and are excellent in storage stability. Among the binder resins, acrylic polymer compounds are used in particular. Thereby, the deterioration of the green sheet after long-time storage, especially after long-time storage at a high temperature, seen when an ether-based polymer compound is used can be suppressed. Moreover, the green sheet 10G for anode support layers which is excellent in roll moldability compared with the case where an ether type polymer compound is used and has a continuously stable quality can be formed. As a result, it is possible to produce an SOFC with high performance and low quality variation.

  As the acrylic polymer compound, various acrylic polymer compounds can be used without particular limitation. For example, a monomer mixture containing alkyl (meth) acrylate as a main monomer (a component occupying more than 50% by weight of the whole monomer) and further containing a submonomer copolymerizable with the main monomer may be used. This monomer mixture may optionally contain other copolymerization components in addition to these main monomer and submonomer. The monomer mixture can be copolymerized to become an acrylic polymer compound having a predetermined function.

In the present specification, “(meth) acrylate” is a term meaning acrylate and methacrylate. Similarly, “(meth) acryl” is a term meaning acryl and methacryl.
As the alkyl (meth) acrylate, for example, a compound represented by the general formula: CH ₂ ═C (R ¹ ) COOR ² can be suitably used. Here, R ¹ in the formula represents a hydrogen atom or a methyl group. R ² represents a chain alkyl group having 1 to 20 carbon atoms. R ² is preferably an alkyl (meth) acrylate that is a chain alkyl group having 1 to 14 carbon atoms, and an alkyl (meth) acrylate that is a chain alkyl group having 1 to 10, for example, 2 to 8 carbon atoms. Is more preferable. Furthermore, an alkyl (meth) acrylate in which R ² is a butyl group or a 2-ethylhexyl group is preferable.

  Examples of the alkyl (meth) acrylate having a chain alkyl group having 1 to 20 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n- Butyl (meth) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) Acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl ( ) Acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) Examples include acrylate and eicosyl (meth) acrylate. These alkyl (meth) acrylates may be used individually by 1 type, and may be used in combination of 2 or more type. Although not particularly limited, preferred alkyl (meth) acrylates include, for example, n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA).

  As a secondary monomer, it has a function of introducing a crosslinking point into the acrylic polymer compound or controlling the binding property of the acrylic polymer compound, and includes various functional groups according to desired binder characteristics. Monomer components can be used. Such functional groups can be, for example, carboxyl groups, hydroxy groups, amide groups, amino groups, epoxy groups, and the like. Although not particularly limited, it is preferable to use an ethylenically unsaturated monomer having a hydroxyl group. The amount of the submonomer is not particularly limited, and can be appropriately designed so as to realize desired adhesion layer characteristics. For example, from the viewpoint of balancing the cohesive strength and adhesiveness of the polymer in a well-balanced manner, the amount of the secondary monomer is 20% by mass or less, more preferably 15% by mass or less, more preferably 15% by mass or less, based on 100% by mass of alkyl (meth) acrylate. It is exemplified that the content is 10% by mass or less. In addition, you may make it include other copolymerization components other than the submonomer illustrated here. What is necessary is just to select suitably the ratio of the submonomer to the said monomer (the total amount of a main monomer and a submonomer) according to the desired degree of crosslinking, for example, about 1-10 mass% with respect to 100 mass% of all monomer components. It can be. The method for polymerizing the monomer mixture is not particularly limited, and conventionally known general polymerization methods (emulsion polymerization, solution polymerization, etc.) can be employed.

Preferred examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl ( (Meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, [4- (hydroxymethyl) cyclohexyl] methyl And hydroxyalkyl (meth) acrylates such as acrylate. A particularly preferred example is 2-hydroxyethyl methacrylate.
In such a binder, those in which 50% by mass or more (more preferably 80% by mass or more, more preferably 90% by mass or more) is an acrylic polymer compound can be preferably used. A particularly preferred example is a binder that is substantially 100% made of an acrylic polymer compound.

  Although not particularly limited, the acrylic polymer compound as the first binder preferably has a glass transition temperature (Tg) of −100 ° C. or higher and 10 ° C. or lower. By using an acrylic polymer compound having a Tg in the above range, the formability when this raw material mixture is subjected to roll forming described later is remarkably improved, and it has excellent storage stability and is uniform and isotropic. A green sheet for anode support layer 10G can be obtained. As a result, it is possible to further suppress variations in the performance of the SOFC manufactured using the green sheets 110G and 120G. If Tg is too lower than −100 ° C., the density of the green sheet for anode support layer 10G obtained by roll forming is increased, but for example, there is a tendency to be slightly inferior in formability at room temperature. Therefore, Tg is preferably −95 ° C. or higher, more preferably −60 ° C. or higher, and particularly preferably −40 ° C. or higher (eg, −30 ° C. or higher). Moreover, when Tg is too higher than 10 ° C., for example, the roll formability of the formed anode support layer green sheet 10G tends to be slightly inferior. Therefore, Tg is preferably 5 ° C. or lower, more preferably 0 ° C. or lower, and more preferably −1 ° C. or lower, for example.

The acrylic polymer compound as the first binder is preferably water-soluble at normal temperature (for example, a temperature range of 10 ° C. to 30 ° C.). This water-soluble polymer may be an acrylic polymer having any nonionic, anionic or cationic hydrophilic group. Particularly preferred is an anionic acrylic polymer compound having an anionic hydrophilic group in the molecular structure. Examples of the anionic hydrophilic group include a carboxyl group (—CO ₂ ⁻ ) and a sulfonic acid group (—SO ₃ ⁻ ). Sodium polyacrylate having such an anionic group and acrylic acid copolymer An acrylic polymer compound such as a polymer can be particularly preferably used. The dissolution conditions for such a water-soluble acrylic polymer compound are not particularly limited, but are preferably neutral or alkaline (for example, about pH 6 to 13, preferably about pH 6 to 10).

  Although not particularly limited, the acrylic polymer compound as the first binder preferably has a nonvolatile content (NV) of 30% to 65%. By using an acrylic polymer compound having NV in the above range, this raw material mixture is preferable because the shape stability after roll molding described later can be improved. When NV is too lower than 30%, there is a possibility that the properties of the obtained anode support layer green sheet 10G, and thus the green sheets 110G and 120G, at high temperatures are likely to be altered. Therefore, NV is preferably 35% or more, and more preferably 40% or more. On the other hand, when NV is too higher than 65%, the roll formability of the anode support layer green sheet 10G tends to be slightly inferior. Therefore, NV is preferably 60% or less, more preferably 55% or less, for example, 50% or less.

  In addition, what is marketed can also be utilized for such an acrylic polymer compound. Although it does not specifically limit, As such an acrylic polymer compound, for example, as an example, AP-60L, AP-80, AP-96, AP-360, AP368, ES-37 manufactured by Japan Coating Resin Co., Ltd. , ES-64, ES-85, ES-232, ES-650, SA-200, HS-531, ESZ-4366-02, FK-285, FK-433, FK-854, FK-4300, Polymer Innovations WB4101 (all are brand names) made from the product etc. are mentioned as a suitable thing.

  The raw material mixture for forming the anode support layer green sheet 10G may further include, for example, a pore former (pore forming material), a plasticizer, an antioxidant, a thickener, as long as the effects of the present invention are not significantly impaired. In addition, various additives such as a dispersant may be included as necessary. As the pore former, for example, carbon, silicon carbide, silicon nitride, starch and the like can be suitably used. Examples of the plasticizer include glycols such as propylene glycol; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, and ethylene glycol isopropyl ether; dibutyl phthalate, dioctyl phthalate, ditridecyl phthalate And the like can be suitably used. As the dispersant, for example, a carboxylic acid polymer surfactant can be suitably used. When using various additives, the ratio of the additive to the whole raw material mixture can be, for example, 0.1% by mass to 20% by mass, and usually about 0.5% by mass to 10% by mass. Is preferred.

  For the preparation of the raw material mixture, various conventionally known stirring / mixing devices such as a ball mill, a mixer, a disper, and a kneader can be appropriately used. For example, a conductive material, a binder, and other components (typically a pore former or a plasticizer) used as necessary are put into an arbitrary stirring / mixing device, and the stirring speed of 50 rpm to 300 rpm is 0.5. A homogeneous raw material mixture can be prepared by stirring and mixing for a period of time to 1 hour. In addition, the order in which the said raw material is thrown into an apparatus is not specifically limited, For example, all the materials may be thrown in at once and you may throw in in multiple times.

  Alternatively, these raw material mixtures may be prepared in the form of granulated particles granulated to a predetermined size. The method for producing the granulated particles is not particularly limited. For example, it may be manufactured by mixing a conductive material and a first binder at a predetermined ratio in a dry or wet manner, and performing granulation, classification, and the like. There is no particular limitation on the granulation method. For example, tumbling granulation method, fluidized bed granulation method, stirring granulation method, compression granulation method, extrusion granulation method, crushing granulation method, spray drying method (spraying method) Granulation method) and the like. In one preferred example, a spray-drying method is employed, and a slurry-like composition (suspension) in which a conductive material and a binder are mixed in a solvent is sprayed into a dry atmosphere and dried to form a granulation (molding). ). In this method, the particles contained in the droplets to be sprayed are granulated in one lump, so that the size and mass of the granulated particles can be easily adjusted depending on the size of the droplets. The droplets to be sprayed may also contain materials other than the conductive material and the first binder, for example, the various additives described above.

  The size of the granulated particles in this case is not particularly limited. For example, from the viewpoint of increasing production efficiency and forming a more homogeneous active material layer, the particle size range is, for example, about 10 μm to 200 μm, preferably 30 μm. It is good that they are 180 micrometers or less, for example, 45 micrometers or more and 150 micrometers or less. The average particle diameter is 20 μm or more and 100 μm or less, preferably 30 μm or more and 90 μm or less, for example, 50 μm or more and 80 μm or less.

  The composition of each material is such that when the anode support layer green sheet 10G is formed, the ratio of the metal-based material (metal or metal oxide) to the whole is about 30% by mass or more (typically 40% by mass). ˜80% by mass), and usually preferably about 45% by mass to 70% by mass. When the solid electrolyte layer forming material (typically an oxide ion conductor) is used, the ratio of the solid electrolyte layer forming material in the entire anode support layer green sheet 10G is, for example, about 10% by mass to 50% by mass. Usually, it is preferably about 20% by mass to 40% by mass. Moreover, the ratio of the binder to the whole anode support layer green sheet 10G can be, for example, about 1% by mass to 20% by mass, and preferably about 2% by mass to 10% by mass. In a particularly preferred configuration, the organic substance content in the anode support layer green sheet 10G is 10% by mass or less (preferably 8% by mass or less, more preferably 7% by mass or less). By reducing the organic content, inconveniences (for example, warpage and deformation, interfacial peeling, formation of through-holes in the solid electrolyte layer, etc.) that may occur when firing the green sheet described later can be further suppressed.

2. Formation of Green Sheet for Anode Support Layer Next, in the manufacturing method disclosed herein, a green sheet 10G for an anode support layer as shown in FIGS. 2A and 2B is formed using the raw material mixture. . The anode support layer green sheet 10G is formed by a roll forming method.
By the way, formation of the green sheet for anode support layers was generally performed using the doctor blade method until now. In such a method, using a blade called a doctor blade, a slurry-like composition obtained by dispersing the above materials in a solvent (typically an organic solvent) is formed to a predetermined thickness, and then the solvent is volatilized. Thus, a green sheet for an anode support layer having a desired thickness was produced. For this reason, it is necessary to give the slurry-like composition a certain degree of viscosity. This may cause a long drying time or may cause environmental hygiene problems during drying. In addition, such a method is easily affected by manufacturing conditions (for example, the viscosity of the slurry-like composition, the drying temperature, etc.), and subtle fluctuations in the conditions may cause cracks and voids in the anode support layer green sheet, The flatness of the surface of the layer green sheet could be lost. Furthermore, when the anode support layer green sheet is formed to be relatively thick (for example, 100 μm to 1500 μm) for use in an anode-supported SOFC, a material having a large specific gravity (typically a metal-based material) is formed at the bottom. The binder that settled down and light in specific gravity was unevenly distributed in the upper part, and the composition and density in the thickness direction could be inhomogeneous. Therefore, in general, a plurality of sheets having a thickness of about 100 μm are produced by the doctor blade method, the sheets are laminated, and the pressure is applied by applying an organic substance as an adhesive between the thermocompression bonding or the sheets, A green sheet for the anode support layer was formed. However, even when a plurality of relatively thin anode support layer green sheets are laminated as described above, the composition and density inhomogeneities in the thickness direction as described above are microscopically eliminated. It wasn't. Further, as the number of laminated sheets increases, the number of interfaces between the sheets increases, and there is a high possibility that voids and poor bonding occur at the interfaces, or interface peeling occurs.

  On the other hand, in the roll forming method disclosed herein, the raw material is compressed with a rotating roll, and a green sheet for an anode support layer having a desired shape is compression-molded. Typically, a raw material is supplied between a pair of rolls rotating in opposite directions, and the raw material is compressed between the pair of rolls to form a desired shape. For this reason, the raw material (material) can be directly put into the roll forming machine as a powder, that is, it is not necessary to prepare the raw material mixture into a slurry. This is also preferable from the viewpoint of work efficiency (typically shortening the drying time), manufacturing cost, and environmental sanitation. Moreover, it is preferable also in the point which does not generate | occur | produce the nonuniformity of the raw material seen when a slurry-like composition is used.

  In a preferred embodiment disclosed herein, the green sheet for anode support layer 10G is preferably formed to have a single-layer structure with an average thickness of 100 μm to 1500 μm. By setting it as the thickness of 100 micrometers or more and 1500 micrometers or less, it can be set as the green sheet 10G for anode support layers excellent in intensity | strength and durability. In addition, with a single layer structure, for example, the number of interfaces is small compared to the case where layers of about 100 μm are laminated and integrated, so that poor bonding between the interfaces hardly occurs, and the anode support layer after firing Resistance can be kept low. Thus, according to the roll forming method, even the relatively thick anode support layer green sheet 10G used in the anode support type SOFC can be stably formed. That is, the anode support layer green sheet 10G can be excellent in isotropy and homogeneity (for example, there is little variation in composition and porosity). The roll forming method is simple because it does not require the preparation of a slurry composition using a solvent, and is preferable from the viewpoint of work efficiency (typically shortening the drying time), production cost, and environmental hygiene.

  FIG. 1 is a schematic cross-sectional view of a roll forming machine according to an embodiment. The roll forming machine 5 shown in FIG. 1 generally includes a storage tank 1 that stores the raw material mixture 1a and a pair of rolls 2.

  The storage tank 1 is a container for storing the raw material mixture 1a. The storage tank 1 also includes a feeder 1b at the bottom thereof, and is configured to continuously supply a certain amount of the raw material mixture 1a between the pair of rolls 2 from the discharge port of the feeder 1b. The feeder 1b is not particularly limited as long as it has excellent quantitativeness. For example, various types of feeders such as a screw type, a vibration type, and a fluid type can be appropriately employed.

  The raw material mixture 1 a supplied between the pair of rolls 2 is drawn between the pair of rolls 2 by the frictional force with the surface of the roll 2, and is compression-molded when passing between the rolls 2. Rolling with the roll 2 may be performed at normal temperature or while heating. Here, the green sheet 10G for anode support layers which has desired properties (for example, thickness and porosity) can be suitably formed by adjusting the conditions of roll forming described later.

  The diameter of the roll 2 is not particularly limited, but may be, for example, about several tens of centimeters to several hundred centimeters. When the raw material mixture and the operating conditions of the roll forming machine are the same, in general, the higher the diameter of the roll, the higher the density (dense) green sheet 10G for the anode support layer can be formed. Further, the press linear pressure between the pair of rolls 2 is not particularly limited, but is usually about 10 kg / mm to 500 kg / mm, for example, about 50 kg / mm to 200 kg / mm. Further, the forming speed of the anode support layer green sheet 10G can be usually about 0.01 m / min to 20 m / min, for example, 0.05 m / min to 10 m / min, preferably 0.1 m / min to 1 m / min. According to such an aspect, inconveniences such as warping and deformation are less likely to occur than in the prior art, and the homogeneous anode support layer green sheet 10G can be formed stably.

  Moreover, the space | interval of a pair of roll 2 is not specifically limited, It can adjust suitably according to the thickness of the green sheet 10G for anode support layers as a target object. The anode support layer green sheet 10G disclosed herein is a SOFC support, for example, compared with a solid electrolyte layer green sheet 20G, a reaction suppression layer green sheet 30G, a cathode layer green sheet (not shown), or the like. And thicker. Since the average thickness of the anode support layer green sheet 10G as a support is usually about 100 μm to 2000 μm, the distance between the pair of rolls 2 is, for example, 100 μm or more (typically 200 μm or more, for example, 300 μm or more). , 2000 μm or less (typically 1800 μm or less, for example, 1500 μm or less). The roll forming method is simple because the anode support layer green sheet 10G having a desired thickness can be formed simply by adjusting the interval between the rolls 2.

3. Formation of Green Sheet for Solid Electrolyte Layer Next, in the manufacturing method disclosed herein, as shown in FIGS. 2 (a) and (b), at least oxide ion conduction is provided on the surface of the anode support layer green sheet 10G. The solid electrolyte layer green sheet 20G including the body and the second binder is formed. Such a solid electrolyte layer green sheet 20G includes, for example, an oxide ion conductor, a second binder, and an additive (for example, a plasticizer) included as necessary on the anode support layer green sheet 10G as a solvent. It can be formed by supplying a slurry composition (slurry for forming a solid electrolyte layer) dispersed in an arbitrary method and removing the solvent.

As the oxide ion conductor, various materials conventionally known as constituent materials for SOFC solid electrolyte layers can be used without any particular limitation. Preferred examples include magnesium (Mg), aluminum (Al), calcium (Ca), scandium (Sc), titanium (Ti), gallium (Ga), strontium (Sr), yttrium (Y), zirconium (Zr), niobium. And oxides containing an element selected from (Nb), barium (Ba), lanthanum (La), cerium (Ce), samarium (Sm), gadolinium (Gd), tungsten (W), and bismuth (Bi). It is done. Specifically, stabilization of yttria (Y ₂ O ₃ ), calcia (CaO), scandia (Sc ₂ O ₃ ), magnesia (MgO), ytterbia (Yb ₂ O ₃ ), erbia (Er ₂ O ₃ ), etc. Cerium oxide (CeO ₂ ) doped with a dopant such as zirconia (ZrO ₂ ), yttria (Y ₂ O ₃ ), gadolinia (Gd ₂ O ₃ ), samaria (Sm ₂ O ₃ ), whose crystal structure is stabilized with an agent ); Any of these may be used alone or in combination of two or more. Among them, yttrium-stabilized zirconia (YSZ) in which yttrium oxide (for example, yttria (Y ₂ O ₃ )) is dissolved in zirconia (ZrO ₂ ), or scandium oxide (for example, scandia (Sc ₂ O ₃ )). Scandia-stabilized zirconia (ScSZ) in which)) is dissolved can be suitably used. Since these oxides can exhibit high oxide ion conductivity even when the temperature is relatively low (about 500 ° C. to 800 ° C.), these oxides are preferable because an SOFC with excellent startability can be realized. The amount of the oxide to be dissolved is not particularly limited, but may be, for example, about 1 mol% to 20 mol% (usually about 5 mol% to 10 mol%).

  The average particle diameter of the oxide ion conductor is preferably equivalent to that of the conductive material exemplified for forming the green sheet for anode support layer 10G (anode support layer). That is, an oxide ion conductor having an average particle size of about 0.01 μm to 5 μm (for example, 0.1 μm to 2 μm) can be preferably used. By aligning the average particle size of the materials contained in the anode support layer green sheet and solid electrolyte layer green sheet, it is possible to improve the adhesion between the two layers and realize higher bondability and mechanical strength. Can do.

  As the second binder, any binder can be used without particular limitation as long as it can be removed by evaporation by removing the binder (typically, heating and baking at 300 ° C. or higher) or baking the green sheet. Specifically, cellulose polymers such as methylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, carboxyethylcellulose, carboxyethylmethylcellulose, and cellulose acetate phthalate; ester-based compounds such as methacrylate esters Polymers; acrylic polymers such as polyvinyl alcohol, polyvinyl butyral, polymethyl methacrylate, polybutyl methacrylate, polymethyl acrylate, polyethyl methacrylate; imide polymers such as polyamideimide and polyimide; ethylene polymers such as polyethylene oxide; polyacrylonitrile; Nito such as polymetallonitrile Le-based polymers; urethane polymer such as polyurethane, polyethylene, polypropylene, polyvinylidene fluoride, polyvinylidene chloride polyvinyl fluoride, vinyl polymer such as vinyl acetate; rubber such as styrene-butadiene rubber; and the like can be used. Especially, a cellulose polymer (for example, ethyl cellulose) and polyvinyl butyral can be used suitably.

  As the solvent, one or two or more of those capable of suitably dispersing (or dissolving) the oxide ion conductor and the second binder can be used without any particular limitation. For example, alcohol solvents, ether solvents, ester solvents, ketone solvents, cyclic ether solvents, aromatic hydrocarbon solvents or other organic solvents can be used. Among them, ethanol, isopropyl alcohol, isobutyl alcohol, octanol, ethylene glycol, α-terpineol, butyl cellosolve acetate, butyl carbitol acetate, butyl diglycol acetate, isobornyl acetate, butyl carbitol, butyl cellosolve, methyl ethyl ketone, cyclohexane, toluene, Xylene or the like can be suitably used. Particularly preferred are α-terpineol, butyl cellosolve acetate, butyl carbitol acetate, butyl diglycol acetate, isobornyl acetate, butyl carbitol and butyl cellosolve.

  In a preferred embodiment, cellulose and a derivative thereof (typically ethyl cellulose) are used as a binder, and α-terpineol is used as a solvent. In another preferred embodiment, polyvinyl butyral is used as a binder, and an ester solvent such as butyl cellosolve acetate, butyl carbitol acetate, butyl diglycol acetate, and isobornyl acetate and / or an alcohol solvent such as isopropyl alcohol. Is to use. According to the study of the present inventor, by forming the solid electrolyte layer green sheet 20G using the binder and the solvent in the above combination, the interface between the anode support layer green sheet 10G and the solid electrolyte layer green sheet 20G. It is preferable because the adhesion can be further enhanced and the occurrence of interface peeling and voids (voids) can be suppressed.

The solid content concentration (NV) of the slurry for forming the solid electrolyte layer green sheet 20G (hereinafter sometimes referred to as “solid electrolyte layer forming slurry”) is not particularly limited. It is preferable to set it as% -80 mass%, for example, it can be set as about 65 mass% -75 mass%. In other words, the ratio of the solvent in the entire solid electrolyte layer forming slurry can be, for example, about 20% by mass to 40% by mass, and is usually preferably about 25% by mass to 35% by mass.
Moreover, the ratio of the oxide ion conductor to the whole solid electrolyte layer forming slurry is about 50% by mass or more, and preferably about 60% by mass to 70% by mass. The proportion of the binder in the entire solid electrolyte layer forming slurry can be, for example, about 1% by mass to 10% by mass, and is usually preferably about 1% by mass to 5% by mass. When using various additives, the ratio of the additive to the whole solid electrolyte layer forming slurry can be, for example, 0.1% by mass to 20% by mass, and usually about 0.5% by mass to 15% by mass. % Is preferable.

  As a method for supplying the slurry for forming the solid electrolyte layer, a general slurry application technique, for example, printing methods (letter printing, offset printing, gravure printing, inkjet printing, screen printing, etc.), sheet forming methods (doctor blade method, etc.) In addition, a dipping method, a spray method, and the like can be employed, and among them, a printing molding method (typically a screen printing method) and a doctor blade method can be preferably employed. According to such a method, it is possible to suitably form a thin green electrolyte sheet 20G for a solid electrolyte layer as compared with the related art.

  In a preferred embodiment of the production method disclosed herein, after the slurry for forming the solid electrolyte layer is supplied, the solvent contained in the slurry for forming the solid electrolyte layer is removed by an appropriate drying method. As such a method, natural drying, hot air, low-humidity air, vacuum, infrared, far-infrared, electron beam, or the like can be used alone or in combination. Thereby, the green sheet 20G for solid electrolyte layers which consists of an oxide ion conductor and a 2nd binder is formed.

In addition, the thickness (average thickness) of the solid electrolyte layer green sheet 20G can be formed thinner than the conventional one. Although the thickness of the solid electrolyte layer green sheet 20G is not strictly limited, the thickness is typically 10 μm or less, for example, 7 μm or less, and particularly preferably 5 μm or less. By setting it as the said range, resistance can be restrained lower and SOFC which can exhibit the outstanding power generation performance (high power density) is realizable. The thickness of the solid electrolyte layer green sheet 20G is typically formed to be 1 μm or more, for example, 2 μm or more, preferably 3 μm or more. By setting the above range, it is possible to suppress the occurrence of inconveniences such as generation of pinholes and coating streaks that may occur during formation of the solid electrolyte layer green sheet 20G, and formation of through holes in the solid electrolyte layer during firing. can do.
As described above, for example, a green sheet 110G in which the anode support layer green sheet 10G and the solid electrolyte layer green sheet 20G are laminated as shown in FIG.

4). Formation of Reaction Inhibiting Layer In a preferred embodiment disclosed herein, for example, as shown in FIG. 2B, a green sheet for reaction inhibiting layer 30G can be provided on the surface of the green sheet for solid electrolyte layer 20G. . For example, when the SOFC solid electrolyte layer contains a zirconium oxide-based material and the cathode layer described later contains an oxide material having a perovskite structure, the solid electrolyte layer in the fired or fired SOFC for producing them A solid phase reaction can occur at the part (interface) where the cathode layer and the cathode layer are in contact. Such a solid phase reaction is not preferable because it can cause a decrease in oxide ion conductivity between the solid electrolyte layer and / or the cathode layer. Therefore, when manufacturing SOFC using the said material, the reaction suppression layer which prevents reaction of both can be provided between a solid electrolyte layer and a cathode layer. Moreover, also about the green sheet 110G disclosed here, the green sheet 30G for reaction suppression layers for forming a reaction suppression layer can be formed on the surface of the green sheet 20G for solid electrolyte layers.

The reaction inhibiting layer green sheet 30G includes, for example, a slurry-like composition (reaction inhibiting) prepared by dispersing cerium oxide, a binder, and an additive (for example, a dispersant) included as necessary in a solvent. The layer forming slurry) can be formed by supplying the surface of the solid electrolyte layer green sheet 20G by any method and then removing the solvent.
As the cerium oxide, for example, cerium oxide exemplified as a material for forming the solid electrolyte layer can be used. A preferable example is cerium oxide (CeO ₂ ) doped with gadolinia (Gd ₂ O ₃ ). The amount of the substitutional constituent element (the doping amount of the different element) is not particularly limited, but can be, for example, 1 mol% to 20 mol% (for example, 5 mol% to 15 mol%) in terms of oxide of the substitution element.

  It does not specifically limit as a binder or a solvent, For example, it can employ | adopt suitably from what was illustrated as an object for formation of the green sheet 20G for solid electrolyte layers. In a preferred aspect, the second binder or solvent used for forming the solid electrolyte layer green sheet 20G is used. For example, cellulose and a derivative thereof (typically ethyl cellulose) can be preferably used as the binder, and α-terpineol can be preferably used as the solvent. Alternatively, polyvinyl butyral can be used as the binder, and an ester solvent such as butyl cellosolve acetate, butyl carbitol acetate, butyl diglycol acetate, or isobornyl acetate can be used as the solvent. According to such a configuration, the affinity (compatibility) between the solid electrolyte layer green sheet 20G and the reaction suppression layer green sheet 30G can be increased, and self-organization can be caused at the interface. Therefore, inconveniences such as interface peeling can be further suppressed, and a high-performance SOFC that can exhibit high power generation performance over a long period can be manufactured. In addition, as an additive of the reaction inhibiting layer green sheet 30G, a carboxylic acid type surfactant (for example, monocarboxylic acid, dicarboxylic acid, etc.) can be preferably used.

The solid content concentration (NV) of the reaction inhibiting layer forming slurry is not particularly limited, but can typically be about 60% by mass to 80% by mass (for example, 65% by mass to 75% by mass), and is generally a solid electrolyte. It is preferable to be equivalent to the layer forming slurry. In other words, the ratio of the solvent in the entire reaction inhibiting layer forming slurry can be, for example, about 20% by mass to 40% by mass, and is usually preferably about 25% by mass to 35% by mass.
Moreover, the ratio of the said cerium oxide to the whole slurry for reaction suppression layer formation is about 50 mass% or more, and it is preferable normally that it is about 60 mass%-70 mass%. The ratio of the binder to the whole reaction inhibiting layer forming slurry can be, for example, about 1% by mass to 10% by mass, and is usually preferably about 1% by mass to 5% by mass. In addition, the preparation method of the slurry for reaction suppression layer formation may be the same as that of the slurry for solid electrolyte layer formation.

The method for supplying the reaction inhibiting layer forming slurry is not particularly limited, but can be the same as that for forming the solid electrolyte layer green sheet 20G. For example, a printing method (for example, a screen printing method) can be employed. And the green sheet 30G for reaction suppression layers can be formed by removing the solvent of the slurry for reaction suppression layer formation supplied.
The thickness of the reaction inhibiting layer green sheet 30G is not particularly limited, but if it is too thick, the oxide ion conductivity of the solid electrolyte layer obtained after firing may be hindered, and the power generation performance may be reduced. On the other hand, if it is too thin, the solid electrolyte layer and the cathode layer may come into contact with each other after firing or may cause a reaction. From this viewpoint, the average thickness of the reaction inhibiting layer green sheet 30G is suitably 0.5 μm to 10 μm, and is usually preferably about 1 μm to 5 μm.
As described above, the green sheet 120G in which the anode support layer green sheet 10G, the solid electrolyte layer green sheet 20G, and the reaction suppression layer green sheet 30G are sequentially laminated as shown in FIG. 2B is manufactured. can do.

[Solid oxide fuel cell (SOFC)]

FIG. 3 is a cross-sectional view illustrating a configuration example of a power generation system including the cylindrical anode-supported SOFC 50 disclosed herein. According to the present invention, there is provided a solid oxide fuel cell (SOFC) 50 including a laminate formed by firing the green sheets 110G and 120G.
Such SOFC 50 can be suitably manufactured, for example, by the following procedure.
[Half-cell]
That is, first, the green sheet 110G produced above is fired (co-fired) at a predetermined temperature to obtain a half cell in which the solid electrolyte layer 20 is formed on the surface of the anode support layer 10. Alternatively, the green cell 120G including the reaction inhibiting layer green sheet 30G is fired (cofired) at a predetermined temperature, and the solid electrolyte layer 20 and the reaction inhibiting layer 30 are sequentially formed on the surface of the anode support layer 10. Get. The temperature at the time of baking at this time can be about 1200 degreeC-1500 degreeC, for example. Moreover, baking time can be made into about 1 hour-5 hours, for example.

The anode support layer 10 has a porous structure with excellent gas diffusibility, and the porosity is usually about 10% to 50% by volume, preferably 20% to 40% by volume. The average pore diameter of the anode support layer 10 is usually about 10 μm or less, preferably 0.1 μm to 5 μm. When satisfying such a range, a sufficient contact area with the gas can be ensured, and high mechanical strength and excellent gas diffusibility can be suitably achieved.
The solid electrolyte layer 20 and the reaction inhibition layer 30 are thin and have a dense structure, and the porosity is usually about 30% by volume or less, preferably 20% by volume or less. When satisfying such a range, an SOFC with higher power density can be realized.
In the present specification, the “average pore diameter” means a value obtained by measurement by a general mercury intrusion method. Further, in this specification, the “porosity” is obtained by dividing the pore volume (Vb (cm ³ )) obtained by the measurement of the mercury intrusion method by the apparent volume (Va (cm ³ )). By multiplying, the calculated value (Vb / Va × 100 (%)) is said.

[Cathode layer]
And the cathode layer 40 can be formed in a half cell by forming the green sheet for cathode layers in the surface of the solid electrolyte layer 20 side (or reaction suppression layer 30 side) of these half cells, and baking again. Thereby, SOFC50 can be manufactured.
The green sheet for the cathode layer is prepared by preparing a slurry-like composition (cathode layer forming slurry) in which a cathode constituent material (for example, perovskite oxide), a binder, and an additive contained as necessary are dispersed in a solvent. In the same manner as the green sheets 20G and 30G for the solid electrolyte layer or reaction suppression layer, it can be formed by supplying a predetermined thickness and removing (drying) the solvent. The SOFC 50 can be manufactured by firing the green sheet laminate for the half cell / cathode layer at a predetermined temperature. The firing temperature at this time can be, for example, 700 ° C. to 1200 ° C. (preferably 800 ° C. to 1100 ° C.), and the firing time can be about 1 hour to 5 hours.

  The fired cathode layer 40 has a porous structure excellent in gas diffusibility like the anode support layer 10, and the porosity is usually about 10% to 30% by volume, and 15% to 25% by volume. It is preferable that Further, the average pore diameter of the cathode layer 40 is usually about 10 μm or less, and preferably 0.1 μm to 5 μm. When satisfying such a range, a sufficient contact area with the gas can be secured and high power generation performance can be realized. The average thickness of the cathode layer 40 is usually about 50 μm or less (typically about 5 μm to 20 μm) from the viewpoint of power generation performance, but is not limited to such thickness.

As a material constituting the cathode layer 40, one kind or two or more kinds of substances conventionally used for forming the cathode layer of SOFC can be used without particular limitation. Among these, those that can exhibit excellent durability in an oxidizing atmosphere are preferable. Typically, lanthanum cobaltite (LaCoO ₃ ), lanthanum manganate (LaMnO ₃ ), lanthanum ferrite (LaFeO ₃ ), lanthanum nickelate (LaNiO ₃ ) perovskite oxides; samarium cobaltite (SmCoO ₃ ) -Based perovskite oxides.

Here, for example, the above lanthanum cobaltite-based oxide is an oxide having La and Co as constituent metal elements, as well as one or more metal elements other than La and Co (transition metal element and / or typical metal element) ) Containing oxides. The same applies to lanthanum manganate oxides, lanthanum ferrite oxides, lanthanum nickelate oxides, and samarium cobaltite oxides. As typical examples, an Sr-doped LaMnO ₃ oxide (eg, La _0.8 Sr _0.2 MnO ₃ ), an Sr-doped LaCoO ₃ oxide (eg, La _0.6 Sr _0.4 CoO _3). ), LaCoO ₃ oxides doped with Sr and Fe (for example, La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ ) and the like. These oxides are so-called electron-oxide ion mixed conductors, and are preferable because they exhibit higher reaction activity (have higher catalytic ability) than other perovskite oxides.

  The cathode layer green sheet can also contain a binder, various additives, and the like as necessary as long as the effects of the present invention are not significantly impaired. For example, one or two or more of those described above for forming the anode support layer green sheet 10G can be used as appropriate.

The SOFC 50 manufactured as described above has a structure in which the anode support layer (fuel electrode) 10, the solid electrolyte layer 20, the reaction suppression layer 30, and the cathode layer (air electrode) 40 are sequentially laminated. doing. Further, the end 12 of the anode support layer 10 and the joining surface of the gas pipe 70 for supplying the fuel gas are joined by the connecting member 60 and sealed so that the gas does not flow out and / or flow in. On the other hand, the cathode layer 40 has a structure exposed to the outside air. When the SOFC 50 is used, a fuel gas (typically hydrogen (H ₂ )) is present on the solid electrolyte surface on the anode support layer 10 side, and an oxygen (O ₂ ) -containing gas (typically on the solid electrolyte surface on the cathode layer 40 side). Air). When a current is applied to the SOFC 50, oxygen is reduced in the cathode layer 40 to become oxide ions. Then, the oxide ions reach the anode support layer 10 (through the solid electrolyte layer 20), oxidize the fuel gas, and emit electrons, thereby generating electric energy (that is, power generation).

  The SOFC shown in FIG. 3 is a cylindrical type (Tubular), but various other structures such as a conventionally known polygonal type, a flat type (Planar), or a flat cylinder in which the peripheral side surface of the cylinder is vertically crushed. The shape (Flat Tubular) can be used, and the shape and size are not particularly limited. For example, the flat type has a feature that it has a high power density and is cheaper than the cylindrical type. In addition, the cylindrical type has a feature that it is easy to keep the gas flow rate constant and more stable power generation is possible. For this reason, it is preferable to select a preferable shape and size as appropriate according to the application. In addition to the anode-supported cell (ASC) disclosed herein, the flat SOFC includes, for example, a metal support cell (porous metal sheet placed under the anode support layer). MSC (Metal-Supported Cell).

  Several examples relating to the present invention will be described below, but the present invention is not intended to be limited to the specific examples.

[Production of green sheets]
(Example 1)
As a conductive material, a nickel oxide (NiO) powder having an average particle diameter of 0.5 μm and an 8 mol% yttria-stabilized zirconia (8YSZ) powder having an average particle diameter of 0.5 μm are mixed at a mass ratio of NiO: 8YSZ = 60: 40. To make a mixed powder. Moreover, the acrylic polymer type | system | group binder 1 whose glass transition temperature (Tg) shown in following Table 1 is -96 degreeC was prepared as a 1st binder. Table 1 also shows properties such as the main composition, ionicity, pH, and amount of nonvolatile components of the first binder. And said mixed powder, a 1st binder, a pore making material (carbon particle), and a plasticizer (glycol ether) are mix | blended by the mass ratio of 100: 7: 10: 3, and ion-exchange water is carried out. In addition, a slurry-like composition was prepared by stirring. Subsequently, using this slurry-like composition, the raw material mixture in the form of granulated particles was prepared by granulating by a spray drying method.

By continuously supplying the raw material mixture prepared as described above between a pair of rolls and compression molding (roll molding method), a sheet-like green sheet for an anode support layer having a thickness of about 0.5 mm is obtained. Formed. The rolling conditions at this time were as follows. A part of the green sheet for anode support layer obtained here was subjected to various characteristics evaluations shown below.
Roll temperature: 30 ° C
Gap between rolls: 500 μm
Roll linear pressure: 100 kg / mm
Molding speed: 0.5m / min

  Next, an 8YSZ powder having an average particle diameter of 0.5 μm, a binder (ethylcellulose; EC), and a solvent (α-terpineol; TE) were kneaded at a mass ratio of 65: 4: 31 to form a slurry. A composition for forming a solid electrolyte layer was prepared. This was supplied (printed) onto the anode support layer green sheet by a screen printing method to form a solid electrolyte layer green sheet having a thickness of 5 μm.

Similarly, by kneading 10% gadolinium-doped ceria (GDC) powder having an average particle size of 0.5 μm, a binder (EC), and a solvent (α-TE) at a mass ratio of 65: 4: 31, A slurry-like composition for forming a reaction inhibition layer was prepared. This was supplied (printed) onto the solid electrolyte layer green sheet by a screen printing method to form a reaction inhibiting layer green sheet having a thickness of 5 μm.
Thereby, the green sheet for SOFC of Example 1 in which the green sheet for the anode support layer, the green sheet for the solid electrolyte layer, and the green sheet for the reaction suppression layer are integrally formed is obtained.

(Example 2)
The SOFC green sheet of Example 2 was obtained in the same manner as in Example 1 except that acrylic polymer binder 2 having a Tg of −44 ° C. was used as the first binder. The other properties of the acrylic polymer binder 2 used in Example 2 are shown in Table 1.

(Example 3)
The SOFC green sheet of Example 3 was obtained in the same manner as in Example 1 except that acrylic polymer binder 3 having a Tg of −30 ° C. was used as the first binder. The other properties of the acrylic polymer binder 3 used in Example 3 are shown in Table 1.

(Example 4)
The SOFC green sheet of Example 4 was obtained in the same manner as in Example 1 except that acrylic polymer binder 4 having a Tg of −3 ° C. was used as the first binder. The other properties of the acrylic polymer binder 4 used in Example 4 are shown in Table 1.

(Example 5)
A SOFC green sheet of Example 5 was obtained in the same manner as in Example 1 except that a polyether binder having a Tg of 61 ° C. was used as the binder when forming the anode support layer green sheet. The other properties of the polyether binder 5 used in Example 5 are shown in Table 1.

(Example 6)
Instead of the roll forming method, a green sheet for an anode support layer was formed by a doctor blade method. That is, an acrylic polymer binder 3 having a Tg of −30 ° C. as in Example 3 was used as the first binder. Then, in the same manner as in Example 1, the mixed powder, the first binder (binder 3), the pore former, and the plasticizer are blended and dispersed in a solvent (α-TE) to form a slurry. The anode forming composition was prepared. First, a slurry-like composition for forming an anode is supplied onto a carrier sheet to produce a sub-sheet having a thickness of about 100 μm. Then, five sub-sheets were cut out to a predetermined size and laminated via an adhesive containing starch to obtain a sheet-like green sheet for an anode support layer having a total thickness of about 0.5 mm.
The others were the same as Example 1 to obtain the SOFC green sheet of Example 6.

[Production of SOFC]
The SOFC green sheets obtained in Examples 1 to 6 were cut out so that the size after firing was a circle with a diameter of 20 mm, and cofired at 1350 ° C. to obtain a SOFC half cell.
Moreover, LSCF powder (La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ powder) having an average particle diameter of 2 μm was prepared as a cathode material. The LSCF powder, the binder (EC), and the solvent (TE) were kneaded at a mass ratio of 80: 3: 17 to obtain a slurry-like composition for forming an air electrode. This was supplied in a circular shape by a screen printing method on the green sheet for reaction suppression layer of the half-cell green sheet of each example prepared above, thereby forming a green sheet for an air electrode layer. Subsequently, this was baked at 1100 degreeC and the air electrode was formed, and SOFC for evaluation of Examples 1-6 was obtained.

[Organic content]
About the green sheet for anode support layers in the said Examples 1-6, the content rate of the organic component contained in a sheet | seat was measured by performing differential thermal and thermogravimetric analysis. Specifically, using a differential thermal-thermogravimetric simultaneous measurement device (Rigaku Corporation, Thermo plus), when the temperature is raised to 500 ° C. at a predetermined temperature increase rate (here, 10 ° C./min) in the air atmosphere. Based on the weight loss profile, the organic substance content in the anode support layer green sheet was measured. And the organic substance content rate (mass%) was computed by remove | dividing the obtained organic substance content by the weight before a measurement. The results are shown in the column of “Organic content” in Table 1.

[Surface roughness]
About the green sheet for anode support layers in the said Examples 1-6, surface roughness was measured based on JISB0601: 2001. Specifically, using a surface roughness measuring instrument (Tokyo Seimitsu Co., Ltd., surfcom120A), the measurement length was 5 mm, and the arithmetic average roughness (Ra) of the surface of the green sheet for anode support layer in each example was measured. The measurement was performed 10 times, and the average value is shown in the column “Ra” in Table 1.

[Tensile strength]
About the green sheet for anode support layers in the above Examples 1 to 6, the tensile strength was measured according to JIS K7161: 1994 (plastic-tensile property test method). The test piece was prepared by punching from the green sheet of each example using a predetermined test piece punching blade. For the measurement, a tensile strength tester (manufactured by Shimadzu Corporation, tabletop tester: EZ-TEST) is used, and the holding jig is held at both ends by the holding jig, and the holding jig is pulled at a pulling speed of 100 mm / min. Moved to. And the tensile fracture stress when the test piece broke was measured, and the tensile strength was obtained by dividing by the cross-sectional area of the test piece. The test was performed 10 times, and the average value is shown in the column of “Tensile strength” in Table 1.

[Green sheet property observation]
The properties of the SOFC green sheets obtained in Examples 1 to 6 were observed, and it was confirmed that there were no defects such as cracks and tears. As the observation method, visual observation and scanning electron microscope (SEM) observation were used in combination. That is, the cross section of the half-cell green sheet was cut out, and a plurality of (10 surfaces) cross sections were observed visually and by SEM, and the presence or absence of cracks, tears, partial peeling, etc. was examined between the respective layers. The result is shown in the column of “Defects during stacking” in Table 1.

[Weight change after holding at high temperature]
The storage characteristics of the SOFC green sheets obtained in Examples 1 to 6 were examined. Specifically, the green sheets of each example were stored in a constant temperature bath at 85 ° C. for 15 days, and the change in weight of the green sheets before and after storage was examined. The results are shown in the column of “weight change after holding at high temperature” in Table 1 as a percentage (%) of the weight loss with respect to the initial weight.

[Characteristic observation after firing]
The laminated state of the half cells obtained in Examples 1 to 6 was observed with eyes and SEM in the same manner as described above, and the half cells were observed for defects such as warpage and interface peeling. The result was shown in the column of “exfoliation after firing” in Table 1 as “present” when there was a defect and “absence” when there was no defect.
In addition, it was confirmed by performing a leak test using alcohol whether or not through holes or the like were formed in the reaction suppression layer and the solid electrolyte layer to cause leakage. Specifically, alcohol is dropped on the surface of the solid electrolyte layer of the half cell of each example, and the presence or absence of leakage of alcohol to the back side of the half cell, that is, the anode is confirmed. When leakage was confirmed within 5 minutes, it was determined that there was a leakage in the solid electrolyte layer. The results are shown in the “Leak after firing” column of Table 1 as “Yes” when there is a leak and “No” when there is no leak.

[Power generation performance]
The power density when the SOFCs of Examples 1 to 6 were operated under the following conditions was measured. As a result, the maximum power density (W / cm ² ) is shown in the “power generation performance” column of Table 1 as the power generation performance.
Fuel electrode supply gas: Hydrogen gas (50 ml / min)
Air electrode supply gas: Air (100 ml / min)
Operating temperature: 700 ° C

As shown in Table 1, in Example 6 in which the green sheet for the anode support layer was formed by the doctor blade method, lamination with an adhesive was necessary, so that the organic matter content rate was significantly increased. It has been found that bubbles are likely to be formed at the bonding interface in the anode support layer and that some sheets are easily torn. And in the half cell after baking, interface peeling and a leak were seen. This is because when the organic matter contained in the green sheet and the bubbles at the bonding interface are burned away by firing, the combustion gas preferentially propagates through the heterogeneous and fragile sites and the interfacial exfoliation part, and the solid electrolyte layer is locally transferred. This is considered to be due to the fact that the through-hole was formed through. In addition, it is considered that the interfacial peeling is caused by the fact that migration occurs within a thickness of about 100 μm until the raw material prepared in a slurry state is dried, and composition unevenness is likely to occur in the thickness direction. When the solid electrolyte layer is thinned, factors such as the uneven structure of the anode support layer by the doctor blade method and the uneven thickness of the solid electrolyte layer, which had not been a problem until now, cause serious defects called through-holes. It is thought that it became. As a result, the power generation performance of SOFC was a very low value of 0.28 W / cm ² .

On the other hand, the green sheets of Examples 1 to 5 formed by the roll forming method do not cause migration or the like in the raw material mixture, and the anode support layer can be formed by one molding, so that the anode support layer is homogeneous as a whole (isotropic It was confirmed that the problem of bubbles, interfacial delamination, and leakage hardly occurred in the cell obtained by firing this structure. The obtained SOFCs had a relatively good value of power generation performance of 0.38 W / cm ² .
However, regarding the green sheet of Example 5 using an ether-based polymer compound as the first binder, the weight change when stored at a high temperature of 85 ° C. for 15 days was extremely large. When the green sheet after high-temperature storage was fired, a large leak occurred after firing. This is presumed that the structure of the green sheet of Example 5 became non-uniform during molding and high-temperature storage, and the heterogeneous portion became more apparent during firing, resulting in interfacial peeling and the like.

On the other hand, it was confirmed that the green sheets of Examples 1 to 4 using the acrylic polymer compound as the first binder showed almost no change in weight even after high temperature storage and the quality was stable. In other words, it was shown that, after the green sheet was manufactured, until it was actually manufactured, even in an environment at a high temperature of 85 ° C., it could be stored with stable quality for 2 weeks or more. Moreover, in Examples 1-4, compared with the case of Example 5, it has confirmed that a high quality green sheet could be continuously manufactured stably by a roll forming method, without causing generation | occurrence | production of a crack.
As can be seen from the comparison of Examples 1 to 4, it was found that the properties of the green sheet for an anode support layer obtained were changed by the Tg of the acrylic polymer compound used as the first binder. That is, even when manufactured under the same roll forming conditions, it was found that the surface roughness of the obtained green sheet for anode support layer becomes smaller and the tensile strength becomes higher as the binder having a larger Tg is used. Among these, it was confirmed that the SOFCs according to Examples 2 to 3 can achieve particularly high power generation performance. Although specific data is not shown, when a binder having a large Tg was used, the density of the green sheet was slightly lowered, but on the contrary, the roll formability was further improved, and as a result, the green sheet It is considered that the smoothness and strength (that is, the binding property of the raw material mixture) has been improved. Along with this, it was confirmed that the power generation performance of the SOFC was also improved.

  From the above results, according to the SOFC green sheet manufacturing method disclosed herein, even when a solid electrolyte layer thinner than the conventional one is formed by screen printing, through holes (leaks) or cracks are formed in the solid electrolyte layer during firing. It is possible to form a high-quality green sheet in which defects such as these are not formed. In addition, since this SOFC green sheet is excellent in storage stability, even if a load is imposed on the time and temperature environment from the production of the green sheet to firing, it does not induce defects in the thin solid electrolyte layer, and the It is possible to manufacture a quality SOFC. Moreover, since the SOFC green sheet is manufactured with good moldability, variations in quality are suppressed. Therefore, the SOFC manufactured using the SOFC green sheet can be one in which variation in performance is suppressed.

  As mentioned above, although the specific example of this invention was demonstrated in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. For example, the conductive materials, oxide ion conductors, cathode constituent materials, and the like in the embodiments exemplified above are merely examples, and it goes without saying that materials other than those described above can be used.

DESCRIPTION OF SYMBOLS 1 Storage tank 1a Raw material mixture 1b Feeder 2 Roll 5 Roll forming machine 10 Anode support layer 10G Green sheet 20 for anode support layer Solid electrolyte layer 20G Green sheet 30 for solid electrolyte layer 30 Reaction suppression layer 30G Green sheet 40 for reaction suppression layer Cathode layer 50 SOFC
60 Joining member 70 Gas pipe 110G Green sheet 120G Green sheet

Claims (14)

A method for producing a green sheet used to form a solid oxide fuel cell comprising:
Providing a raw material mixture including at least a conductive material and a first binder, wherein the first binder is an acrylic polymer;
Forming a green sheet for an anode support layer by roll forming the raw material mixture;
Forming a solid electrolyte layer green sheet including at least an oxide ion conductor and a second binder on a surface of the anode support layer green sheet;
Manufacturing method.   The said acrylic polymer compound is a manufacturing method of Claim 1 whose glass transition temperature is -100 degreeC or more and 10 degrees C or less.   The green sheet for the solid electrolyte layer is formed by a printing method or a doctor blade method according to claim 1 or 2.   The said green sheet for anode support layers is a manufacturing method of any one of Claims 1-3 formed so that an organic substance content rate may be 10 mass% or less.   5. The manufacturing method according to claim 1, wherein the green sheet for an anode support layer is formed to have a single layer structure with an average thickness of 100 μm to 1500 μm.   The manufacturing method according to any one of claims 1 to 5, wherein the second binder includes at least one of polyvinyl butyral and ethyl cellulose. The roll forming is performed by supplying the raw material mixture between a pair of rolling rolls and performing compression forming, and the following conditions:
(1) adjusting the temperature of the pair of rolls to be higher than the softening temperature of the first binder;
(2) adjusting the distance between the pair of rolls to be 100 μm or more and 1500 μm or less;
(3) The roll linear pressure is set to 0.1 kN / cm or more and 30 kN / cm or less; and (4) The molding speed is set to 0.1 m / min or more and 20 m / min or less;
The manufacturing method of any one of Claims 1-6 which comprises all.   The method according to any one of claims 1 to 7, further comprising forming a green sheet for a reaction inhibition layer containing at least cerium oxide on a surface of the green sheet for a solid electrolyte layer. A green sheet used to form a solid oxide fuel cell,
At least a green sheet for an anode support layer, and a green sheet for a solid electrolyte layer laminated on the green sheet for an anode support layer,
The anode support layer green sheet includes at least a conductive material and a first binder, and has a single-layer structure having an average thickness of 100 μm to 1500 μm formed by a roll forming method ,
The first binder is an acrylic polymer compound,
The green sheet for forming a solid oxide fuel cell, wherein the green sheet for a solid electrolyte layer includes at least an oxide ion conductor and a second binder.   The green sheet according to claim 9, wherein the organic substance content of the green sheet for an anode support layer is 10% by mass or less.   The green sheet according to claim 9 or 10, wherein the second binder contains at least one of polyvinyl butyral and ethyl cellulose.   The green sheet according to any one of claims 9 to 11, comprising a green sheet for a reaction inhibition layer containing at least cerium oxide on a surface of the green sheet for a solid electrolyte layer. The green sheet for an anode support layer is a roll formed body in which granulated particles formed by granulation containing at least a conductive material and a first binder are roll-formed into a single layer structure having an average thickness of 100 μm to 1500 μm. Because
The first binder is an acrylic polymer compound,
The green sheet according to any one of claims 9 to 12, wherein the solid electrolyte layer green sheet includes at least an oxide ion conductor and a second binder. A solid oxide fuel cell comprising a laminate formed by firing the green sheet according to any one of claims 9 to 13 .

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