JP2010287440A - Solid-oxide fuel cell and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-oxide fuel cell having improved productivity and reduced cost as well as improved air tightness, durability and heat cycling efficiency; and to provide a method of manufacturing the same. <P>SOLUTION: A fuel cell stack 104 has gas seal parts for sealing spaces between members to prevent gas leakage to the outside. Specifically, the gas seal parts of atmosphere joining brazing materials 131-134 are formed between a power generation cell 102 and a metal cell cover 121, between a metal separator 122 and the metal cell cover 121, between the metal separator 122 and an insulating manifold 142, and between the metal cell cover 121 and the insulating manifold 142. The gas seal parts are joined together in a brazing step using an atmosphere brazing method. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a solid oxide fuel cell having a gas seal portion that seals between members to prevent gas leakage to the outside.

  A solid oxide fuel cell (SOFC) is a fuel cell that operates at about 800 ° C. to 1000 ° C. to achieve high power generation efficiency. 2. Description of the Related Art A fuel cell includes a single cell (single cell) including a cell that generates power (hereinafter referred to as a power generation cell) and a separator that performs gas supply and electrical connection.

  The power generation cell has an oxide three-layer structure in which a fuel electrode and an air electrode are provided on both sides of a solid oxide electrolyte (hereinafter, electrolyte). As a constituent material of the separator, a metal containing an alloy (for example, ferritic stainless steel) is used. The separator has a manifold as a component for supplying gas to the power generation cell, fuel gas is supplied from the fuel electrode side manifold to the fuel electrode, and air is supplied from the air electrode side manifold to the air electrode.

  In a single cell, when a fuel gas is supplied to the fuel electrode and air is supplied to the air electrode, an electrochemical reaction occurs. In this case, the obtained voltage is low, so that a practical voltage can be obtained. A stack is made by stacking a plurality of single cells.

  In the single cell and stack of the fuel cell, the operating temperature is about 800 ° C. to 1000 ° C., so the fuel gas, air, fuel off gas, and air off gas supplied thereto are all gases, and the outside of these gases In order to prevent leakage to the gas, gas seals are provided between the parts. When the gas seal part is insufficient in gas tightness, gas leakage occurs, causing deterioration of power generation performance and battery destruction. Therefore, the gas seal part is required to have high air tightness. In addition, since a heat cycle is generated by starting and stopping, the gas seal portion is also required to have good heat cycle characteristics.

  In the single cell, a gas seal portion is provided between the power generation cell and the separator, and as a seal material used there, for example, a paste-like glass seal material is disclosed (for example, Patent Documents 1 and 2). Moreover, the technique which brazes and joins metal foil between a power generation cell and a separator is disclosed (for example, patent document 3). In the stack, a gas seal portion is provided between single cells, and as a seal material used there, a paste-like glass seal material is used as in the single cell. In this case, as a characteristic required for the sealing material, in addition to the above-described characteristic in the case of a single cell, electrical insulation for preventing an electrical short circuit can be mentioned.

  The manufacturing process of the stack is generally determined by the type of sealing material used for the gas seal portion. As the sealing material, a method using an active metal brazing material and a method using only a glass sealing material have been proposed. In the method using an active metal brazing material, a glass sealing material is used in combination.

  In the method using an active metal brazing material, the process shown in FIG. 3 is performed. FIG. 3 is a side sectional view showing a manufacturing process of an active metal brazing method for joining using an active metal brazing material. In the active metal brazing method, first, as shown in FIG. 3A, after obtaining a co-sintered body 201 (fuel electrode-electrolyte co-sintered body 201) of the fuel electrode 211 and the electrolyte 212, in a reducing atmosphere, The fuel electrode 211 is reduced by heating the fuel electrode-electrolyte co-sintered body 201 at 800 to 1200 ° C.

  Subsequently, as shown in FIG. 3B, an active metal brazing material 231 is applied to the outer peripheral portion of the upper surface of the fuel electrode-electrolyte co-sintered body 201. Next, as shown in FIG. 3C, after the end portion of the metal cell cover 221 is placed on the active metal brazing material 231, it is heated at 780 to 1200 ° C. in a vacuum or inert atmosphere, The electrolyte co-sintered body 201 and the metal cell cover 221 are joined by brazing. In this case, the active metal brazing material 231 constitutes a gas seal part. Next, as shown in FIG. 3 (D), the air electrode 213 is applied to the center of the upper surface of the fuel electrode-electrolyte co-sintered body 201 and heated at 1000 to 1200 ° C. in an air atmosphere. -The air electrode 213 is sintered on the electrolyte co-sintered body 201. Thereby, the power generation cell 202 to which the metal cell cover 221 is joined is manufactured.

  Next, as shown in FIG. 3E, a glass sealing material 232 is applied to the outer periphery of the lower surface of the metal cell cover 221 and the metal cell cover 221 is joined to the upper surface of the metal separator 222 having a concave central portion. A power generation cell 202 is arranged. In this case, a current collector 241 is interposed between the metal separator 222 and the power generation cell 202. A single cell 203 having a configuration in which the power generation cell 202 is sandwiched between the metal cell cover 221 and the metal separator 222 is obtained.

  Next, as illustrated in FIG. 3F, a glass sealing material 233 is applied to the outer peripheral portion of the upper surface of the metal cell cover 221 of the single cell 203, and the insulator manifold 242 is attached with the glass sealing material 233. Subsequently, a glass sealing material 234 is applied to the upper surface of the insulator manifold 242, and the single cell 204 is disposed by the glass sealing material 234. By repeating such a process, a fuel cell stack 204 in which a predetermined number of layers are stacked is obtained.

  Next, the members are bonded to each other by the glass sealing materials 232 to 234 by heating the stack 204 by raising the temperature to the glass softening point in the air atmosphere. In this case, the glass sealing materials 232 to 234 constitute a gas seal portion. Then, it becomes possible to start as a battery by heating the stack 204 at 800 to 900 ° C. in an air atmosphere. In this case, since the air electrode 113 is made of an oxide, the heat treatment atmosphere is limited to the air atmosphere.

  In the method using only the glass sealing material as the sealing material, the process shown in FIG. 4 is performed. First, as shown in FIG. 4A, a power generation cell 302 having a fuel electrode 311 and an air electrode 313 provided on both sides of an electrolyte 312 is prepared. Next, as shown in FIG. 4B, the power generation cell 303 is disposed in the center of the concave metal separator 322, and the glass sealing material 332 is placed on the outer peripheral surface of the metal separator 322 and the outer peripheral surface of the power generation cell 302. 331 is applied. In this case, a current collector 341 is interposed between the metal separator 322 and the power generation cell 303. Next, as shown in FIG. 4C, a metal cell cover 321 is attached with glass sealing materials 332 and 331. As a result, a single cell 303 having a configuration in which the power generation cell 302 is sandwiched between the metal cell cover 321 and the metal separator 322 is obtained.

  Subsequently, as shown in FIGS. 4D and 4E, the insulator manifold 342 is interposed in the same manner as in the method using the active metal brazing material (step shown in FIGS. 3F and 3G). By sticking the single cells 303 together with the glass sealing materials 333 and 343, the fuel cell stack 204 is obtained. Next, by raising the temperature to the glass softening point in the air atmosphere and heating the stack 204, the members are bonded together by the glass sealing material. Next, by heating the stack 304 at 800 to 900 ° C. in an air atmosphere, the battery can be started.

JP 2004-319286 A JP 2005-327555 A Japanese Patent Laid-Open No. 10-32244

  However, in the method using the active metal brazing material 231 as the sealing material, it is necessary to perform at least three heat treatments in addition to the heat treatment for starting the battery, so that productivity is low and cost reduction is difficult. In particular, in bonding using an active metal such as Ti, heat treatment in a vacuum and an inert atmosphere is essential, which increases the manufacturing cost and requires a lot of time.

  Further, the glass sealing materials 232 to 234 used in the production of a stack in which the single cells 203 are stacked have insufficient strength as a sealing material for a fuel cell, and have brittle characteristics at temperatures below the softening point. For this reason, cracking or peeling tends to occur when the temperature is lowered from the operating temperature. If the glass sealing materials 232 to 234 are broken once, the gas tightness is lost, and if the temperature is raised again to the operating temperature, the equivalent performance cannot be obtained, and the thermal cycleability is impaired. Moreover, there exists a possibility that the component of the glass sealing materials 232-234 may inhibit an electrode reaction, and the glass sealing material and the metal component of a separator may react and cause deterioration. When the glass sealing material is used in this manner, airtightness, durability, and thermal cycle performance associated with start-up / operation / stop are lowered.

  On the other hand, in the method using only the glass sealing materials 331 to 334 as the sealing material, since the heat treatment necessary other than the heat treatment for starting the battery is one time, the stack manufacturing process can be simplified. Productivity can be improved and costs can be reduced. However, when the glass sealing materials 331 to 334 are used, as in the case of the glass sealing materials 232 to 234 described above, the airtightness, durability, and thermal cycle characteristics associated with start-up / operation / stop are lowered.

  Therefore, the present invention can improve productivity and reduce costs, as well as a solid oxide fuel cell capable of improving airtightness, durability, and thermal cycleability, and its The object is to provide a manufacturing method.

  The solid oxide fuel cell of the present invention has a gas seal portion that seals between members to prevent gas leakage to the outside, and the gas seal portion is made of a brazing material for atmospheric bonding. Yes.

  The solid oxide fuel cell of the present invention is manufactured by the following manufacturing method. That is, the method for producing a solid oxide fuel cell according to the present invention is a method for producing the above solid oxide fuel cell, wherein the members are joined in a brazing process using an air brazing method. It is characterized by performing at least two of them simultaneously.

  Various configurations can be used for the solid oxide fuel cell of the present invention. A solid oxide fuel cell according to the present invention includes a power generation cell, a metal separator and a metal cell cover that sandwich the power generation cell, and an insulator manifold provided between ends of the metal separator and the metal cell cover. Gas seals provided as members, between power generation cells and metal cell covers, between metal separators and metal cell covers, between metal separators and insulator manifolds, and between metal cell covers and insulator manifolds Can be provided.

  In the method for producing a solid oxide fuel cell according to the present invention, the members in the gas seal portion are joined to each other in the brazing process using the atmospheric brazing method, which is different from the active metal brazing method that requires heat treatment at least three times. Since the necessary heat treatment is performed once, productivity improvement and cost reduction can be achieved. In addition, unlike the active metal brazing method using an active metal such as Ti, the heat treatment atmosphere can be set to an air atmosphere, so that it is not necessary to set a vacuum or an inert atmosphere. Shortening can be achieved and further cost reduction can be achieved. Furthermore, when the brazing material for air bonding is used, the bonding between metals, bonding between ceramics, and bonding between metal and ceramics can be easily performed without flux in the air atmosphere. Further, since it is well maintained even in a high-temperature hydrogen / oxygen atmosphere, it is possible to improve the gas tightness, durability, and thermal cycle performance of the gas seal portion. Note that the brazing filler metal for atmospheric bonding can be used for at least one gas seal portion, and when used for all gas seal portions, the above effect can be effectively obtained, which is preferable.

  Various structures can be used in the method for producing a solid oxide fuel cell of the present invention. The brazing process can be performed in an air atmosphere at a temperature of 800 ° C. or higher and 970 ° C. or lower. Further, the brazing material for air bonding used in the brazing process contains Ag as a main component, Ge, Si, Cr, Al, Au, Pd, Sb, Bi, and oxides of these elements as additive elements Of at least one of the following. Furthermore, in the air brazing method, a heating means used for starting operation of the fuel cell can be used. In this aspect, since the heating means usually used for the start-up operation of the fuel cell can be used, it is not necessary to separately prepare a heating means for joining the brazing material for atmospheric joining, and the heat treatment step is separately performed. Since it is not necessary, the manufacturing time can be further shortened and the cost can be further reduced.

As the insulator manifold, a ceramic material containing magnesia as a main component and alumina and yttria as additive elements can be used. For the insulator manifold, a ceramic material composed of magnesia 70 wt% or more and 80 wt% or less, alumina 15 wt% or more and 25 wt% or less, and yttria more than 0 wt% and 8 wt% or less can be used. In this aspect, when ferritic stainless steel is used for the metal cell cover and metal separator of the joining partner, the thermal expansion coefficient of the insulator manifold is equal to the thermal expansion coefficient (10.0 × 10 ^{−6 to} 14.0 × 10 ⁻⁶ ° C. ⁻¹ ), the bonding between the insulator manifold and the metal separator and the bonding between the insulator manifold and the metal cell cover are good.

  When stacking a plurality of single cells to assemble a stack and sandwiching the stack between the first member and the second member, a ceramic is formed between at least one of the first member and the second member and the stack. These elastic members can be used. In this aspect, not only can electrical insulation be ensured, but also the sag resistance can be improved, and the problem caused by a single load can be solved.

  According to the solid oxide fuel cell of the present invention or the manufacturing method thereof, the required heat treatment is performed once, and it is not necessary to set the heat treatment atmosphere to a vacuum or an inert atmosphere. In addition, the manufacturing time can be shortened and the cost can be reduced. Further, it is possible to improve the gas tightness, durability, and thermal cycle performance of the gas seal portion.

(A)-(E) are sectional side views showing each process of the manufacturing method of the solid oxide fuel cell which concerns on one Embodiment of this invention. It is a sectional side view showing the process of the manufacturing method of the solid oxide fuel cell following FIG. (A)-(G) are sectional side views showing each process of the manufacturing method of the conventional solid oxide fuel cell. (A)-(E) are side sectional drawings showing each process of the manufacturing method of the conventional solid oxide fuel cell. The cross sectional structure of the gas seal part (atmospheric bonding brazing filler metal layer) between the power generation cell (cell) and the metal cell cover is shown, (A) is a secondary electron image of the whole cross section (× 40), and (B) is an enlarged cross section. It is a secondary electron image (× 500). Represents a cross-sectional configuration of a gas seal part (a brazing filler metal layer) between a metal separator and a metal cell cover, (A) is an overall cross-section secondary electron image (× 40), (B) is an enlarged cross-sectional secondary It is an electronic image (x500). Represents the cross-sectional configuration of the gas seal part (atmosphere bonding brazing filler metal layer) between the metal separator and the insulator manifold, (A) is the overall cross-section secondary electron image (× 40), (B) is the enlarged cross-sectional secondary It is an electronic image (x500).

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1A to 1E are side cross-sectional views showing respective steps of a method for manufacturing a solid oxide fuel cell according to an embodiment of the present invention. FIG. 2 is a side sectional view showing a process of the method for manufacturing a solid oxide fuel cell following FIG.

  Reference numeral 102 denotes a power generation cell (FIG. 1A), reference numeral 103 denotes a single cell (FIG. 1C), and reference numeral 104 denotes a stack ((FIG. 1E)). In the solid oxide fuel cell (hereinafter referred to as fuel cell) of the present embodiment, the power generation cell 102 is disposed in the recess in the center of the upper surface of the metal cell cover 121, and the power generation cell 102 is sandwiched between the metal cell cover 121 and the metal separator 122. Is in the form of A plurality of single cells 104 having such a configuration are stacked with the insulator manifold 142 therebetween, thereby forming the stack 104.

  In the stack 104, between the power generation cell 102 and the metal cell cover 121, between the metal cell cover 121 and the metal separator 122, between the metal separator 122 and the insulator manifold 142, and between the metal cell cover 121 and the insulator manifold. Between 142, a gas seal portion made of brazing materials 131 to 134 for air bonding is formed.

  A manufacturing method of a solid oxide fuel cell (hereinafter referred to as a fuel cell) according to this embodiment includes a power generation cell preparation step (FIG. 1A), an air bonding brazing material coating step, and a stack assembly step (FIG. 1). (B) to 1 (E), FIG. 2) and a heat treatment step in the air atmosphere.

  First, in a power generation cell preparation step, as shown in FIG. 1A, a power generation cell 102 having a fuel electrode 111 and an air electrode 113 on both sides of a solid oxide electrolyte 112 (hereinafter referred to as an electrolyte) is prepared. Next, in the air bonding brazing material application step, the air bonding brazing materials 131 to 134 are applied to the gas seal portion formation scheduled portion. Specifically, the air bonding brazing material 131 is applied to the outer peripheral portion of one surface of the electrolyte 112 of the power generation cell 102 on the air electrode 113 side, and the air bonding brazing material 132 is applied to the outer peripheral portion of the upper surface of the metal separator 122. An air bonding brazing material 133 is applied to the upper surface of the insulator manifold 142, and an air bonding brazing material 134 is applied to the outer periphery of the upper surface of the metal cell cover 121.

  The material of the air bonding brazing material contains Ag as a main component, and contains at least one of Ge, Si, Cr, Al, Au, Pd, Sb, Bi, and oxides of these elements as additive elements. . The form of the brazing material for air bonding is not particularly limited, and examples thereof include paste, foil, wire, slurry, sol, and powder. The method for applying the air bonding brazing material is not particularly limited, and examples thereof include dispensing application and screen printing. The current collector is preferably a porous body of Ni, Ag, or an alloy containing these metals, and examples of the shape include a fine wire shape, a mesh shape, a lattice shape, a mat shape, and a foam metal body shape.

  Subsequently, in the stack assembling step, as shown in FIG. 1B, the power generation cell 102 is disposed in the center of the upper surface of the concave metal separator 122 with the current collector 141 therebetween. In this case, instead of arranging the current collecting material 141, the air bonding brazing material may be used and applied as a current collecting layer.

  Next, as shown in FIG. 1C, the metal cell cover 121 is disposed on the air bonding brazing materials 131 and 132 applied to the outer periphery of the upper surface of the power generation cell 102 and the outer periphery of the upper surface of the metal separator 122. As a result, the single cell 103 having a configuration in which the power generation cell 102 is sandwiched between the metal cell cover 121 and the metal separator 122 is obtained. Next, as shown in FIG. 1D, the insulator manifold 142 having the air bonding brazing material 133 applied on the upper surface is disposed on the air bonding brazing material 134 of the metal cell cover 121.

The insulator manifold 142 is an electrical insulating member that prevents a short circuit between the single cells 103. As the insulator manifold 142, an MgO ceramic material is used. Specifically, as the insulator manifold 142, a ceramic material containing magnesia as a main component and alumina and yttria as additive elements is used. More specifically, the insulator manifold uses a ceramic material containing magnesia in the range of 70 wt% to 80 wt%, alumina in the range of 15 wt% to 25 wt%, and yttria in excess of 0 wt% to 8 wt%. In this embodiment, when ferritic stainless steel is used for the metal cell cover 121 and the metal separator 122 to be joined, the thermal expansion coefficient of the insulator manifold 142 is equivalent to the thermal expansion coefficient (10 0.0 × 10 ^{−6 to} 14.0 × 10 ⁻⁶ ° C. ⁻¹ ), the bonding between the insulator manifold and the metal separator and the bonding between the insulator manifold and the metal cell cover are good.

  Subsequently, as illustrated in FIG. 1E, the single cell 103 is stacked over the insulator manifold 142. In this case, the current collector 142 is disposed between the air electrode 113 of the lower unit cell 103 and the metal separator 122 of the upper unit cell 103. Thus, a fuel cell stack 104 is obtained. In the present embodiment, an example in which the stack 104 is composed of two single cells 103 has been shown, but a fuel cell stack in which a predetermined number of layers are stacked by repeating the steps shown in FIGS. 1 (B) to 1 (E). Is obtained.

  Next, as shown in FIG. 2, the stack 104 is sandwiched by the first member 151 and the second member 152 which are plate materials, and the members are fastened by the bolt 153. In this case, for example, a ceramic elastic member 154 (for example, a spring) is disposed between the first member 151 and the metal cell cover 121 of the upper unit cell 103. In this aspect, not only can electrical insulation be ensured, but also the sag resistance can be improved, and the problem caused by a single load can be solved.

  Next, in the atmospheric heat treatment step, the fuel cell stack 104 is put into an atmospheric furnace and heated in the atmospheric air at 800 to 970 ° C. for a predetermined time (for example, 5 to 60 minutes). Thereby, the brazing filler metals 131 to 134 in the gas seal portion are melted, and good gas tightness can be obtained in the gas seal portion. In such heat treatment, a heating means for starting and operating the fuel cell can be used instead of the atmospheric furnace. In this case, for example, when the operating temperature of the fuel cell is 800 ° C. and the bonding temperature of the air bonding brazing materials 131 to 134 is 970 ° C., the bonding temperature of the air bonding brazing materials 131 to 134 is first in the air atmosphere. After raising the temperature to 970 ° C. and holding this state for 5 to 60 minutes, the temperature can be lowered to 800 ° C., which is the operating temperature of the fuel cell, and the battery can be started.

  The whole cross-section secondary electron image of the gas seal part of the experimental example of the fuel cell manufactured by the above manufacturing method is shown in FIGS. In the experimental example, the paste described in Japanese Patent Application No. 2009-056805 proposed by the present applicant is used as the form of the brazing material for air bonding, and the screen printing method is used as the coating method of the brazing material for air bonding. It was.

  FIG. 5 shows a cross-sectional configuration of a gas seal part (atmospheric bonding brazing filler metal layer) between the power generation cell (cell) and the metal cell cover, and FIG. 6 shows a gas seal part between the metal separator and the metal cell cover ( FIG. 7 shows a cross-sectional configuration of the gas seal portion (atmospheric bonding brazing material layer) between the metal separator and the insulator manifold. 5-7, (A) is a whole cross-section secondary electron image (x40), and (B) is an enlarged cross-section secondary electron image (x500). As can be seen from FIGS. 5 to 7, it was confirmed that in each gas seal portion, a brazing filler metal layer having high adhesion to the mating member was formed. Thereby, it was confirmed that the gas tightness of the gas seal portion can be improved by joining the members using the atmospheric brazing method in the gas seal portion.

  As described above, in the present embodiment, since the gas seal portion is joined in the brazing process using the atmospheric brazing method, unlike the active metal brazing method in which the heat treatment is required at least three times, the necessary heat treatment is performed once. Therefore, productivity can be improved and costs can be reduced. In addition, unlike the active metal brazing method using an active metal such as Ti, the heat treatment atmosphere can be set to an air atmosphere, so that it is not necessary to set a vacuum or an inert atmosphere. Shortening can be achieved and further cost reduction can be achieved. Furthermore, when air bonding brazing materials 131 to 134 are used, in an air atmosphere, metal-to-metal bonding, ceramic-to-ceramic bonding, and metal-to-ceramic bonding can be easily performed without flux. Since the bonding interface is satisfactorily maintained even in a high-temperature hydrogen / oxygen atmosphere, it is possible to improve the gas tightness, durability, and thermal cycle performance of the gas seal portion.

  In particular, since the heating means usually used for the start-up operation of the fuel cell can be used, it is not necessary to separately prepare a heating means for joining the brazing materials 131 to 134 for the air joining, and the heat treatment process is separately provided. Since it is not necessary to perform this, the manufacturing time can be shortened and the cost can be further reduced.

  While the present invention has been described with reference to the above embodiment, the present invention is not limited to the above embodiment, and various modifications can be made. For example, the fuel cell manufacturing method of the present embodiment is an example of the solid oxide fuel cell manufacturing method of the present invention, and it goes without saying that various modifications are possible within the scope of the present invention. For example, in the above-described embodiment, the air bonding brazing material is applied to each gas seal portion formation scheduled portion in the air bonding brazing material applying step, but the air bonding brazing material may be appropriately applied when each member is installed. Good. Moreover, in the air atmosphere heat treatment step, the members in all the gas seal portions are joined at the same time, but the members in at least two gas seal portions may be joined at the same time.

  DESCRIPTION OF SYMBOLS 102 ... Power generation cell, 103 ... Single cell, 104 ... Stack, 121 ... Metal cell cover, 122 ... Metal separator, 131-134 ... Brazing material (gas seal part) for atmospheric joining, 142 ... Insulator manifold, 154 ... Elastic member

Claims (9)

It has a gas seal part that seals between members and prevents gas leakage to the outside,
The gas seal portion is made of a brazing material for air bonding, and is a solid oxide fuel cell. A power generation cell, a metal separator and a metal cell cover that sandwich the power generation cell, and an insulator manifold provided between ends of the metal separator and the metal cell cover as the member,
Between the power generation cell and the metal cell cover, between the metal separator and the metal cell cover, between the metal separator and the insulator manifold, and between the metal cell cover and the insulator manifold. The solid oxide fuel cell according to claim 1, wherein the gas seal portion is provided in the fuel cell. In the manufacturing method of the solid oxide fuel cell according to claim 1 or 2,
The members are joined in a brazing process using an atmospheric brazing method,
A method for producing a solid oxide fuel cell, wherein at least two of the brazing steps are simultaneously performed.   The method for producing a solid oxide fuel cell according to claim 3, wherein the brazing step is performed in an air atmosphere at a temperature of 800 ° C or higher and 970 ° C or lower.   The brazing material for air bonding used in the brazing step contains Ag as a main component, Ge, Si, Cr, Al, Au, Pd, Sb, Bi, and oxides of these elements as additive elements The method for producing a solid oxide fuel cell according to claim 3 or 4, comprising at least one kind.   The method for producing a solid oxide fuel cell according to any one of claims 3 to 5, wherein the atmospheric brazing method uses a heating means used for start-up operation of the fuel cell.   The method of manufacturing a solid oxide fuel cell according to any one of claims 3 to 6, wherein a ceramic material containing magnesia as a main component and alumina and yttria as additive elements is used as the insulator manifold. .   8. The ceramic material containing magnesia of 70 wt% or more and 80 wt% or less, alumina of 15 wt% or more of 25 wt% or less, and yttria of more than 0 wt% and 8 wt% or less is used as the insulator manifold. A method for producing a solid oxide fuel cell according to claim 1. When stacking a plurality of single cells to assemble a stack and sandwiching the stack between the first member and the second member,
9. The solid oxide fuel cell according to claim 3, wherein a ceramic elastic member is used between at least one member of the first member and the second member and the stack. Production method.

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