JP5770355B2 - Fuel cell structure and fuel cell stack structure - Google Patents

Description

  The present invention relates to a fuel cell structure and a fuel cell stack structure.

  Conventionally, “a cell having a longitudinal direction provided with a support substrate in which a gas flow path is formed” and “the cells protrude from the surface of the support plate along the longitudinal direction, and the plurality of cells are stacked. A support plate that joins and supports one end in the longitudinal direction of each cell using a joining material so as to be aligned in a shape, and “inner space of the manifold and each of the gas flow paths of the plurality of cells”. A stack structure of a solid oxide fuel cell including a gas manifold provided with the support plate so as to communicate with one end is known (for example, see Patent Document 1). Here, the support plate also functions as “a partition member for preventing mixing of the fuel gas supplied to the fuel electrode and the gas containing oxygen supplied to the air electrode”. Accordingly, the bonding material also has a sealing function for preventing mixing of the fuel gas and the gas containing oxygen.

JP 2005-1000068 A

  In order to enhance the sealing function of the bonding material, a substance (typically crystallized glass) containing sodium (Na), potassium (K), or the like can be used as the material of the bonding material. This is based on the fact that sodium, potassium, and the like are contained in the bonding material, so that the “wetting property” of the bonding material is increased, and the adhesion of the portion (surface) bonded by the bonding material is increased. Note that crystallized glass is obtained by crystallizing (solidifying or ceramicizing) an amorphous material by subjecting an amorphous material (amorphous glass) to heat treatment (crystallization treatment). It can be defined that the degree is 60% or more.

  Sodium and potassium have the property of corroding stainless steel in a high-temperature atmosphere such as 600 to 900 ° C. In view of this point, sodium and potassium are hereinafter referred to as “corrosive substances”. Usually, in the stack structure described above, “members made of stainless steel” (hereinafter referred to as “stainless steel members”), such as the “manifold” and the “connecting member that electrically connects adjacent cells”. Is also called).

  In the stack structure described above, when a substance containing a corrosive substance is used as the material of the bonding material as described above, the corrosive substance can be evaporated from the bonding material at the operating temperature of the fuel cell. The evaporated corrosive substance can reach the “stainless steel member”. As a result, a problem may occur that the “stainless steel member” is easily corroded by corrosive substances.

  An object of the present invention is to provide a fuel cell structure in which “a member made of stainless steel” is hardly corroded while maintaining good adhesion between a cell and a partition member.

  The structure of the fuel cell according to the present invention includes a "cell configured to include a fuel electrode, an air electrode, and a solid electrolyte positioned between the fuel electrode and the air electrode" and "the cell A partition member for preventing mixing of a fuel gas supplied to the fuel electrode and a gas containing oxygen supplied to the air electrode, the partition member being joined to the cell using a joining material ”.

  The fuel cell structure is characterized in that the bonding material is composed of a substance containing the corrosive substance, and is suitable for a space in the bonding material through which the fuel gas passes during operation of the fuel cell. The “existing surface” is covered with a film of a substance not containing the corrosive substance. The “surface” can also be described as “a surface that is exposed to fuel gas during operation of the fuel cell, assuming that it is not covered with a film of a substance that does not contain corrosive substances”. Here, the film may be dense or porous. The thickness of the film is preferably 1 μm or more. In the film, “not containing a corrosive substance” means that the content of the corrosive substance is 0.5% by weight or less. The content of the corrosive substance in the “substance containing corrosive substance” constituting the bonding material is 5 to 40% by weight.

  When the “surface facing the space through which the fuel gas passes” in the bonding material is made of a substance containing a corrosive member, the corrosive substance evaporated from the surface of the bonding material is “faced in the space through which the fuel gas passes. The phenomenon of reaching the “stained stainless steel member” may occur. On the other hand, in the said structure, the same surface in the said joining material is covered with the film | membrane of the substance which does not contain a corrosive member. Therefore, the above phenomenon cannot occur (or becomes difficult to occur), and as a result, the problem of “corrosion of the stainless steel member existing facing the space through which the fuel gas passes” does not occur (or occurs). It becomes difficult.)

  In addition, the bonding material is composed of a substance containing a corrosive substance. Therefore, by improving the “wetting property” of the bonding material, the adhesion of the portion bonded by the bonding material is increased. As described above, according to the above configuration, the stainless steel member that faces the space through which the fuel gas passes is hardly corroded while maintaining good adhesion between the cell and the partition member.

  When the above-described fuel cell structure according to the present invention is applied to the fuel cell stack structure described in the “Background Art” section, the “support plate” corresponds to the “partition member”. . In this case, the bonding material is made of a substance containing a corrosive substance, and “a fuel gas supplied to the gas flow path through the manifold during operation of the fuel cell” in the bonding material. The surface facing the space through which is passed is covered with a film of a substance that does not contain corrosive substances. Here, the “surface facing the space through which the fuel gas passes” can also be described as “surface facing the internal space of the manifold”.

  The operation and effect of the configuration in which the “surface facing the space through which the fuel gas passes during operation of the fuel cell” in the bonding material is covered with the “film of a substance not containing a corrosive substance” has been described above. However, the same applies to the structure in which the “surface facing the space through which the gas containing oxygen passes during operation of the fuel cell” in the bonding material is covered with the “film of a substance not containing a corrosive substance”. An effect | action and an effect can be show | played.

  That is, the problem of “corrosion of the stainless steel member facing the space through which air passes” does not occur (or is difficult to occur). In addition, by improving the “wetting property” of the bonding material due to the inclusion of the corrosive substance in the bonding material, the adhesion of the portion bonded by the bonding material is increased. As mentioned above, according to the said structure, the stainless steel member which exists facing the space which air passes through becomes difficult to corrode, maintaining the adhesiveness of a cell and a partition member favorably.

  In the fuel cell structure according to the present invention, the film of the substance not containing the corrosive substance is a porous film, the thickness of the film is 1 to 10 μm, and the porosity of the film is 10 to 10 μm. It is suitable that it is 40 volume%. This point will be described in detail later.

It is a perspective view which shows one cell used for the stack structure of the fuel cell which concerns on embodiment of this invention. It is sectional drawing corresponding to the 2-2 line of the cell shown in FIG. It is the top view which showed the state of the fuel electrode and interconnector which were embed | buried under the recessed part of the support substrate shown in FIG. It is a figure for demonstrating the operation state of the cell shown in FIG. It is a figure for demonstrating the flow of the electric current in the operating state of the cell shown in FIG. It is a perspective view which shows the support substrate shown in FIG. FIG. 3 is a cross-sectional view corresponding to FIG. 2 in a first stage in the manufacturing process of the cell shown in FIG. 1. FIG. 3 is a cross-sectional view corresponding to FIG. 2 in a second stage in the manufacturing process of the cell shown in FIG. 1. FIG. 3 is a cross-sectional view corresponding to FIG. 2 in a third stage in the manufacturing process of the cell shown in FIG. 1. FIG. 4 is a cross-sectional view corresponding to FIG. 2 in a fourth stage in the manufacturing process of the cell shown in FIG. 1. FIG. 6 is a cross-sectional view corresponding to FIG. 2 in a fifth stage in the manufacturing process of the cell shown in FIG. 1. FIG. 6 is a cross-sectional view corresponding to FIG. 2 in a sixth stage in the manufacturing process of the cell shown in FIG. 1. FIG. 8 is a cross-sectional view corresponding to FIG. 2 in a seventh stage in the process of manufacturing the cell shown in FIG. 1. FIG. 8 is a cross-sectional view corresponding to FIG. 2 in an eighth stage in the manufacturing process of the cell shown in FIG. 1. 1 is an overall perspective view of a stack structure of a fuel cell according to an embodiment of the present invention. FIG. 16 is an overall perspective view of the fuel gas manifold shown in FIG. 15. It is an enlarged view of the insertion hole formed in the support plate shown in FIG. It is the longitudinal cross-sectional view which showed the mode of the junction part of an insertion hole and the one end part of a cell. It is the cross-sectional view which showed the mode of the junction part of an insertion hole and the one end part of a cell. It is the figure which showed a mode that fuel gas and air were supplied / discharged with respect to the stack | stuck structure shown in FIG. It is the figure which showed the detail of the joining material which joins and seals a support substrate and the one end part of a cell. FIG. 20 is a view corresponding to FIG. 19 in the case where one end portions of a plurality of cells are inserted into one insertion hole. It is a figure corresponding to FIG. 18 in the case where a cell is arrange | positioned with respect to a support plate so that the one end part of a cell may not enter into the hole of a support plate. FIG. 24 is a diagram corresponding to FIG. 21 in the example illustrated in FIG. 23. It is a front view of the whole stack structure of a fuel cell concerning other embodiments of the present invention. It is the figure which showed the detail of the joining material which joins and seals the interconnector and the one end part of a cell in the example shown in FIG.

(Example of cell configuration used for stack structure)
First, a cell 100 used in a stack structure of a solid oxide fuel cell (SOFC) according to an embodiment of the present invention will be described. As shown in FIG. 1, this cell 100 is electrically connected in series to the upper and lower surfaces (main surfaces (planes) on both sides parallel to each other) of a flat plate-like support substrate 10 having a longitudinal direction (x-axis direction). A plurality (four in this example) of the same power generation element portions A connected to each other are arranged at a predetermined interval in the longitudinal direction, so-called “horizontal stripe type”.

  The shape of the entire cell 100 viewed from above is, for example, a rectangle with a side length L1 in the longitudinal direction of 50 to 500 mm and a length L2 in the width direction (y-axis direction) perpendicular to the longitudinal direction of 10 to 100 mm. Yes (L1> L2). The total thickness L3 of the cell 100 is 1 to 5 mm (L2> L3). The entire cell 100 has a vertically symmetrical shape with respect to a plane passing through the center in the thickness direction and parallel to the main surface of the support substrate 10. Hereinafter, in addition to FIG. 1, details of the cell 100 will be described with reference to FIG. 2, which is a partial cross-sectional view of the cell 100 corresponding to line 2-2 shown in FIG. 1. FIG. 2 is a partial cross-sectional view showing a configuration (part of) each of a typical pair of adjacent power generation element portions A and A and a configuration between the power generation element portions A and A. The configuration between the other power generation element portions A and A in other sets is the same as the configuration shown in FIG.

  The support substrate 10 is a flat plate-like fired body made of a porous material having no electronic conductivity. As shown in FIG. 6 to be described later, a plurality of (six in this example) fuel gas passages 11 (through holes) extending in the longitudinal direction are provided in the support substrate 10 at predetermined intervals in the width direction. Is formed. In this example, each recess 12 includes a bottom wall made of the material of the support substrate 10 and side walls closed in the circumferential direction made of the material of the support substrate 10 over the entire circumference (two side walls along the longitudinal direction and the width direction). A rectangular parallelepiped depression defined by two side walls).

The support substrate 10 can be made of, for example, CSZ (calcia stabilized zirconia). Alternatively, it may be composed of NiO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia), NiO (nickel oxide) and Y ₂ O ₃ (yttria), or MgO. (Magnesium oxide) and MgAl ₂ O ₄ (magnesia alumina spinel) may be used.

  The support substrate 10 may be configured to include “transition metal oxide or transition metal” and insulating ceramics. As the “transition metal oxide or transition metal”, NiO (nickel oxide) or Ni (nickel) is suitable. The transition metal can function as a catalyst for promoting a reforming reaction of the fuel gas (hydrocarbon-based gas reforming catalyst).

Further, as the insulating ceramic, MgO (magnesium oxide) or “mixture of MgAl ₂ O ₄ (magnesia alumina spinel) and MgO (magnesium oxide)” is preferable. Further, CSZ (calcia stabilized zirconia), YSZ (8YSZ) (yttria stabilized zirconia), Y ₂ O ₃ (yttria) may be used as the insulating ceramic.

  As described above, since the support substrate 10 contains “transition metal oxide or transition metal”, the gas containing the residual gas component before the reforming is supplied to the fuel through the numerous pores inside the porous support substrate 10. In the process of being supplied from the gas flow path 11 to the fuel electrode, the catalytic action can promote the reforming of the residual gas component before the reforming. In addition, the insulating property of the support substrate 10 can be ensured by the support substrate 10 containing insulating ceramics. As a result, insulation between adjacent fuel electrodes can be ensured.

  The thickness of the support substrate 10 is 1 to 5 mm. Hereinafter, only the configuration on the upper surface side of the support substrate 10 will be described in consideration of the fact that the shape of the structure is vertically symmetrical. The same applies to the configuration of the lower surface side of the support substrate 10.

  As shown in FIGS. 2 and 3, the entire fuel electrode current collector 21 is embedded (filled) in each recess 12 formed in the upper surface (upper main surface) of the support substrate 10. Therefore, each fuel electrode current collector 21 has a rectangular parallelepiped shape. A recess 21 a is formed on the upper surface (outer surface) of each fuel electrode current collector 21. Each recess 21a has a rectangular parallelepiped shape defined by a bottom wall made of the material of the fuel electrode current collector 21 and side walls closed in the circumferential direction (two side walls along the longitudinal direction and two side walls along the width direction). It is a depression. Of the side walls closed in the circumferential direction, two side walls along the longitudinal direction are made of the material of the support substrate 10, and two side walls along the width direction are made of the material of the fuel electrode current collector 21.

  The entire anode active portion 22 is embedded (filled) in each recess 21a. Accordingly, each fuel electrode active portion 22 has a rectangular parallelepiped shape. A fuel electrode 20 is configured by the fuel electrode current collector 21 and the fuel electrode active unit 22. The fuel electrode 20 (fuel electrode current collector 21 + fuel electrode active part 22) is a fired body made of a porous material having electron conductivity. The two side surfaces and the bottom surface along the width direction of each anode active portion 22 are in contact with the anode current collecting portion 21 in the recess 21a.

  A recess 21b is formed in a portion of the upper surface (outer surface) of each fuel electrode current collector 21 excluding the recess 21a. Each recess 21b has a rectangular parallelepiped shape defined by a bottom wall made of the material of the fuel electrode current collector 21 and side walls closed in the circumferential direction (two side walls along the longitudinal direction and two side walls along the width direction). It is a depression. Of the side walls closed in the circumferential direction, two side walls along the longitudinal direction are made of the material of the support substrate 10, and two side walls along the width direction are made of the material of the fuel electrode current collector 21.

  An interconnector 30 is embedded (filled) in each recess 21b. Accordingly, each interconnector 30 has a rectangular parallelepiped shape. The interconnector 30 is a fired body made of a dense material having electronic conductivity. The two side surfaces and the bottom surface along the width direction of each interconnector 30 are in contact with the fuel electrode current collector 21 in the recess 21b.

  The upper surface (outer surface) of the fuel electrode 20 (the fuel electrode current collector 21 and the fuel electrode active unit 22), the upper surface (outer surface) of the interconnector 30, and the main surface of the support substrate 10 form one plane (recessed portion). The same plane as the main surface of the support substrate 10 when 12 is not formed) is formed. That is, no step is formed between the upper surface of the fuel electrode 20, the upper surface of the interconnector 30, and the main surface of the support substrate 10.

The fuel electrode active part 22 can be composed of, for example, NiO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia). Or you may comprise from NiO (nickel oxide) and GDC (gadolinium dope ceria). The fuel electrode current collector 21 can be composed of, for example, NiO (nickel oxide) and YSZ (8YSZ) (yttria stabilized zirconia). Alternatively, it may be composed of NiO (nickel oxide) and Y ₂ O ₃ (yttria), or may be composed of NiO (nickel oxide) and CSZ (calcia stabilized zirconia). The thickness of the anode active portion 22 is 5 to 30 μm, and the thickness of the anode current collecting portion 21 (that is, the depth of the recess 12) is 50 to 500 μm.

  As described above, the fuel electrode current collector 21 includes a substance having electronic conductivity. The fuel electrode active part 22 includes a substance having electron conductivity and a substance having oxygen ion conductivity. The “volume ratio of the substance having oxidative ion conductivity relative to the total volume excluding the pore portion” in the anode active portion 22 is the “oxygen ion conductivity relative to the entire volume excluding the pore portion” in the anode current collecting portion 21. It is larger than the “volume ratio of the substance having”.

The interconnector 30 can be composed of, for example, LaCrO ₃ (lanthanum chromite). Alternatively, it may be composed of (Sr, La) TiO ₃ (strontium titanate). The thickness of the interconnector 30 is 10 to 100 μm.

  The entire surface excluding the central portion in the longitudinal direction of each portion where the plurality of interconnectors 30 are formed on the outer peripheral surface extending in the longitudinal direction of the support substrate 10 in a state where the fuel electrode 20 and the interconnector 30 are embedded in the respective recesses 12. Is covered with a solid electrolyte membrane 40. The solid electrolyte membrane 40 is a fired body made of a dense material having ionic conductivity and not electron conductivity. The solid electrolyte membrane 40 can be made of, for example, YSZ (8YSZ) (yttria stabilized zirconia). Or you may comprise from LSGM (lantern gallate). The thickness of the solid electrolyte membrane 40 is 3 to 50 μm.

  That is, the entire outer peripheral surface extending in the longitudinal direction of the support substrate 10 in a state where the fuel electrode 20 is embedded in each recess 12 is covered with a dense layer composed of the interconnector 30 and the solid electrolyte membrane 40. This dense layer exhibits a gas sealing function that prevents mixing of the fuel gas flowing in the space inside the dense layer and the air flowing in the space outside the dense layer.

  As shown in FIG. 2, in this example, the solid electrolyte membrane 40 covers the upper surface of the fuel electrode 20, both end portions in the longitudinal direction on the upper surface of the interconnector 30, and the main surface of the support substrate 10. Here, as described above, no step is formed between the upper surface of the fuel electrode 20, the upper surface of the interconnector 30, and the main surface of the support substrate 10. Therefore, the solid electrolyte membrane 40 is flattened. As a result, compared with the case where a step is formed in the solid electrolyte membrane 40, the generation of cracks in the solid electrolyte membrane 40 due to stress concentration can be suppressed, and the gas sealing function of the solid electrolyte membrane 40 is reduced. Can be suppressed.

  An air electrode 60 is formed on the upper surface of a portion in contact with each fuel electrode active part 22 in the solid electrolyte membrane 40 via a reaction preventing film 50. The reaction preventing film 50 is a fired body made of a dense material, and the air electrode 60 is a fired body made of a porous material having electron conductivity. The shape of the reaction preventing film 50 and the air electrode 60 viewed from above is substantially the same rectangle as the fuel electrode active part 22.

The reaction preventing film 50 can be made of, for example, GDC = (Ce, Gd) O ₂ (gadolinium-doped ceria). The thickness of the reaction preventing film 50 is 3 to 50 μm. The air electrode 60 can be made of, for example, LSCF = (La, Sr) (Co, Fe) O ₃ (lanthanum strontium cobalt ferrite). Alternatively, from LSF = (La, Sr) FeO ₃ (lanthanum strontium ferrite), LNF = La (Ni, Fe) O ₃ (lanthanum nickel ferrite), LSC = (La, Sr) CoO ₃ (lanthanum strontium cobaltite), etc. It may be configured. Further, the air electrode 60 may be configured by two layers of a first layer (inner layer) made of LSCF and a second layer (outer layer) made of LSC. The thickness of the air electrode 60 is 10 to 100 μm.

  The reaction preventing film 50 is interposed because the YSZ in the solid electrolyte film 40 and the Sr in the air electrode 60 react with each other in the SOFC during the production or operation of the SOFC, and the solid electrolyte film 40 and the air electrode. This is to suppress the occurrence of a phenomenon in which a reaction layer having a large electric resistance is formed at the interface with the substrate 60.

  Here, the laminated body formed by laminating the fuel electrode 20, the solid electrolyte membrane 40, the reaction preventing membrane 50, and the air electrode 60 corresponds to the “power generation element portion A” (see FIG. 2). In other words, a plurality (four in this example) of power generating element portions A are arranged on the upper surface of the support substrate 10 at a predetermined interval in the longitudinal direction.

  For each pair of adjacent power generation element portions A and A, the air electrode 60 of one power generation element portion A (on the left side in FIG. 2) and the interconnector of the other power generation element portion A (on the right side in FIG. 2). The air electrode current collecting film 70 is formed on the upper surfaces of the air electrode 60, the solid electrolyte film 40, and the interconnector 30. The air electrode current collector film 70 is a fired body made of a porous material having electron conductivity. The shape of the air electrode current collector film 70 as viewed from above is a rectangle.

The air electrode current collector film 70 can be made of, for example, LSCF = (La, Sr) (Co, Fe) O ₃ (lanthanum strontium cobalt ferrite). Alternatively, LSC = (La, Sr) CoO ₃ (lanthanum strontium cobaltite) may be used. Or you may comprise from Ag (silver) and Ag-Pd (silver palladium alloy). The thickness of the air electrode current collector film 70 is 50 to 500 μm.

  By forming each air electrode current collecting film 70 in this way, for each pair of adjacent power generation element portions A and A, the air electrode 60 of one power generation element portion A (on the left side in FIG. 2), The other fuel electrode 20 (particularly, the fuel electrode current collector 21) of the power generating element part A (on the right side in FIG. 2) passes through the “air electrode current collector film 70 and interconnector 30” having electronic conductivity. Are electrically connected. As a result, a plurality (four in this example) of power generation element portions A arranged on the upper surface of the support substrate 10 are electrically connected in series. Here, the “air electrode current collector film 70 and the interconnector 30” having electronic conductivity correspond to the “electrical connection part”.

  The interconnector 30 corresponds to the “first portion made of a dense material” in the “electrical connection portion” and has a porosity of 10% or less. The air electrode current collecting film 70 corresponds to the “second portion made of a porous material” in the “electrical connection portion”, and has a porosity of 20 to 60%.

As described above, as shown in FIG. 4, the fuel gas (hydrogen gas or the like) flows through the fuel gas flow path 11 of the support substrate 10 with respect to the “horizontal stripe type” cell 100 shown in FIG. 10 by exposing the upper and lower surfaces (in particular, each air electrode current collecting film 70) to “gas containing oxygen” (air or the like) (or flowing a gas containing oxygen along the upper and lower surfaces of the support substrate 10), An electromotive force is generated by an oxygen partial pressure difference generated between both side surfaces of the solid electrolyte membrane 40. Furthermore, when this structure is connected to an external load, chemical reactions shown in the following formulas (1) and (2) occur, and current flows (power generation state).
(1/2) · O ₂ + 2e ⁻ → O ²⁻ (where: air electrode 60) (1)
H ₂ + O ²⁻ → H ₂ O + 2e ⁻ (in the fuel electrode 20) (2)

  In the power generation state, as shown in FIG. 5, a current flows as indicated by an arrow in each pair of adjacent power generation element portions A and A. As a result, as shown in FIG. 4, from the entire cell 100 (specifically, in FIG. 4, the interconnector 30 of the power generating element part A on the foremost side and the air electrode 60 of the power generating element part A on the farthest side) The power is removed.

(Production method)
Next, an example of a manufacturing method of the “horizontal stripe type” cell 100 shown in FIG. 1 will be briefly described with reference to FIGS. 6 to 14, “g” at the end of the reference numeral of each member represents that the member is “before firing”.

  First, a support substrate molded body 10g having the shape shown in FIG. 6 is produced. The molded body 10g of the support substrate is manufactured by using a method such as extrusion molding or cutting using a slurry obtained by adding a binder or the like to the material of the support substrate 10 (for example, CSZ). obtain. Hereinafter, the description will be continued with reference to FIGS. 7 to 14 showing partial cross sections corresponding to line 7-7 shown in FIG. 6.

  When the support substrate molded body 10g is manufactured as shown in FIG. 7, the fuel electrode current collector is then placed in each recess formed in the upper and lower surfaces of the support substrate molded body 10g as shown in FIG. Each of the molded parts 21g is embedded and formed. Next, as shown in FIG. 9, a molded body 22g of the fuel electrode active portion is embedded and formed in each recess formed in the outer surface of the molded body 21g of each fuel electrode current collector. The molded body 21g of each fuel electrode current collector and each of the fuel electrode active parts 22g use, for example, a slurry obtained by adding a binder or the like to the powder of the material of the fuel electrode 20 (for example, Ni and YSZ), It is embedded and formed using printing methods.

Subsequently, as shown in FIG. 10, in each concave portion formed in “the portion excluding the portion where the molded body 22 g of the fuel electrode active portion is embedded” on the outer surface of the molded body 21 g of each fuel electrode current collector. The interconnector molded bodies 30g are respectively embedded and formed. The molded body 30g of each interconnector is embedded and formed by using a slurry obtained by adding a binder or the like to the material of the interconnector 30 (for example, LaCrO ₃ ), using a printing method or the like. .

  Next, as shown in FIG. 11, the outer periphery extending in the longitudinal direction of the molded body 10g of the support substrate in a state in which the molded body (21g + 22g) of the plurality of fuel electrodes and the molded body 30g of the plurality of interconnectors are respectively embedded and formed. A solid electrolyte membrane molded film 40g is formed on the entire surface excluding the central portion in the longitudinal direction of each portion where the plurality of interconnector molded bodies 30g are formed. The molded membrane 40g of the solid electrolyte membrane is formed using, for example, a printing method, a dipping method, etc., using a slurry obtained by adding a binder or the like to the powder of the material of the solid electrolyte membrane 40 (for example, YSZ). The

  Next, as shown in FIG. 12, a reaction prevention film molding film 50g is formed on the outer surface of the solid electrolyte membrane molding body 40g in contact with the fuel electrode molding body 22g. The molded film 50g of each reaction preventing film is formed using a slurry obtained by adding a binder or the like to the powder of the material (for example, GDC) of the reaction preventing film 50, using a printing method or the like.

  Then, 10 g of the support substrate molded body in which various molded films are thus formed is fired in air at 1500 ° C. for 3 hours. Thereby, the structure of the state in which the air electrode 60 and the air electrode current collection film | membrane 70 are not formed in the cell 100 shown in FIG. 1 is obtained.

  Next, as shown in FIG. 13, an air electrode forming film 60 g is formed on the outer surface of each reaction preventing film 50. The molded film 60g of each air electrode is formed using a slurry obtained by adding a binder or the like to the powder of the material of the air electrode 60 (for example, LSCF), using a printing method or the like.

  Next, as shown in FIG. 14, for each pair of adjacent power generation element portions, air is formed so as to straddle the air electrode molding film 60 g of one power generation element portion and the interconnector 30 of the other power generation element portion. On the outer surface of the electrode forming film 60 g, the solid electrolyte film 40, and the interconnector 30, the air electrode current collecting film forming film 70 g is formed. The forming film 70g of each air electrode current collector film is obtained by using a slurry obtained by adding a binder or the like to the powder of the material of the air electrode current collector film 70 (for example, LSCF), using a printing method or the like. It is formed.

  Then, the support substrate 10 in which the molded films 60g and 70g are thus formed is baked in air at 1050 ° C. for 3 hours. Thereby, the cell 100 shown in FIG. 1 is obtained. In the above, an example of the manufacturing method of the cell 100 shown in FIG. 1 was demonstrated.

  At this time, the Ni component in the fuel electrode 20 is NiO by firing in an oxygen-containing atmosphere. Therefore, in order to acquire these electroconductivity, after that, reducing fuel gas is flowed from the support substrate 10 side, and NiO is reduced at 800 to 1000 ° C. for 1 to 10 hours. This reduction process may be performed during power generation.

(Example of overall structure of stack structure)
Next, a stack structure of a solid oxide fuel cell (SOFC) according to an embodiment of the present invention using the above-described cell 100 will be described. As shown in FIG. 15, the stack structure includes a large number of cells 100 and a fuel gas manifold 200 for supplying a fuel gas to each of the large number of cells 100. The entire manifold 200 is made of a material such as stainless steel.

  The top plate of the manifold 200 (in other words, the top plate (flat plate) of the gas tank) also serves as a support plate 210 for supporting a large number of cells 100. The manifold 200 is provided with an introduction passage 220 for introducing fuel gas from the outside into the internal space of the manifold 200. One end of each cell 100 in the longitudinal direction is formed on the support plate 210 so that each cell 100 protrudes along the longitudinal direction (x-axis direction) from the surface of the support plate 210 and the plurality of cells 100 are aligned in a stack. Bonded and supported (details of the bonding structure will be described later). The other end in the longitudinal direction of each cell 100 is a free end. Therefore, this stack structure can be expressed as a “cantilever stack structure”.

  As shown in FIG. 16, a large number of insertion holes 211 communicating with the internal space of the manifold 200 are formed on the surface of the support plate 210 (the top plate of the manifold 200). One end of the corresponding cell 100 is inserted into each insertion hole 211. As shown in FIG. 17, each insertion hole 211 has an oval shape (L4> L5) having a length L4 and a width L5, and has a symmetric axis direction (y-axis direction) with respect to line symmetry.

  The length L4 of the insertion hole 211 is 0.2 to 3 mm longer than the length L2 (see FIG. 1) of the side surface of one end of the cell 100. Similarly, the width L5 of the insertion hole 211 is 0.2 to 3 mm larger than the width L3 (see FIG. 1) of the side surface of one end of the cell 100. That is, as shown in FIGS. 18 and 19, one end portion of the cell 100 is arranged such that the length direction of the side surface of one end portion of the cell 100 is along the direction of the axis of symmetry of the insertion hole 211 (length direction of the insertion hole 211). Is inserted into the insertion hole 211, a gap is formed between the inner wall of the insertion hole 211 and the outer wall of one end of the cell 100. In other words, one end of the cell 100 is loosely fitted in the insertion hole 211. In FIG. 18 and FIG. 19 (particularly FIG. 19), the gap is exaggerated.

  As shown in FIGS. 18 and 19, solidified bonding material 300 is provided so as to fill the gap in each of the bonding portions between the insertion hole 211 and one end of the cell 100. Thereby, each insertion hole 211 and the one end part of the corresponding cell 100 are joined and fixed, respectively. As shown in FIG. 18, one end of the gas flow path 11 of each cell 100 communicates with the internal space of the manifold 200.

  Also, as shown in FIG. 18, between adjacent cells 100, 100, between adjacent cells 100, 100 (more specifically, the fuel electrode 20 of one cell 100 and the air electrode of the other cell 100). A current collecting member 400 for electrically connecting 60) in series is interposed. The current collecting member 400 is made of, for example, a mesh made of stainless steel. In addition, a current collecting member 500 for electrically connecting the front side and the back side of each cell 100 in series is also provided.

The bonding material 300 is, for example, a crystallization containing a corrosive substance (Na, K, etc.) such as SiO ₂ —MgO—Al ₂ O ₃ —K ₂ O, SiO ₂ —MgO—Al ₂ O ₃ —Na ₂ O. Can be composed of glass. Further, the bonding material 300 includes SiO ₂ —MgO—CaO—K ₂ O, SiO ₂ —MgO—CaO—Na ₂ O, SiO ₂ —MgO—ZnO—K ₂ O, and SiO ₂ —MgO—ZnO—Na ₂ O. It can also be constituted by a substance containing a corrosive substance (Na, K, etc.). In this specification, crystallized glass means that the ratio (crystallinity) of “volume occupied by crystal phase” to the total volume is 60% or more, and “volume occupied by amorphous phase and impurities relative to the total volume”. "Indicates a glass (amorphous) with a ratio of less than 40%. The crystallinity of the crystallized glass is specifically determined by, for example, “the crystal phase and the composition after the crystal phase is identified by using XRD or the like and crystallized by using SEM and EDS or SEM and EPMA. The volume ratio of the crystal phase region is calculated based on the result of observing the distribution. The coating films 310 and 320 of the bonding material 300 will be described later.

  When the cantilever stack structure of the fuel cell described above is operated, as shown in FIG. 20, fuel gas (eg, hydrogen) at a high temperature (eg, 600 to 800 ° C.) and “gas containing oxygen (eg, air) ) ". The fuel gas introduced from the introduction passage 220 moves into the internal space of the manifold 200 and is then introduced into the gas flow path 11 of the corresponding cell 100 via each insertion hole 211. The fuel gas that has passed through each gas flow path 11 is then discharged from the other end (free end) of each gas flow path 11 to the outside. Air flows in the width direction (y-axis direction) of the cells 100 along the gaps between the adjacent cells 100 in the stack structure.

  The above-mentioned cantilever stack structure is assembled by the following procedure, for example. First, a required number of completed cells 100 and a completed manifold 200 are prepared. Next, the plurality of cells 100 are aligned and fixed in a stack using a predetermined jig or the like. Next, one end of each of the plurality of cells 100 is inserted into the corresponding insertion hole 211 of the support plate 210 at a time while maintaining the state in which the plurality of cells 100 are aligned and fixed in a stack. Next, a paste containing a material for the bonding material 300 is filled in each gap of the bonding portion between the insertion hole 211 and one end of the cell 100. At that time, as shown in FIG. 18, the paste may be supplied to the joint to the extent that it protrudes upward from the surface of the support plate 210.

  Next, heat treatment is applied to the paste filled as described above. This heat treatment solidifies and pastes the paste. As a result, the bonding material 300 exhibits a function, and one end of each cell is bonded and fixed to the corresponding insertion hole 211. In other words, one end of each cell 100 is joined and supported by the support plate 210 using the joining material 300. Thereafter, the predetermined jig is removed from the plurality of cells 100 to complete the above-described cantilever stack structure. The coating films 310 and 320 of the bonding material 300 will be described later.

  Here, the support plate 210 also functions as “a partition member for preventing mixing of the fuel gas supplied to the fuel electrode 20 and the air supplied to the air electrode 60”. Therefore, the bonding material 300 has not only a function of bonding the support plate 210 and one end of each cell 100 but also a sealing function for preventing mixing of fuel gas and air.

(Inhibition of mixing of corrosive substances evaporated from bonding materials into fuel gas and air)
As described above, the substances constituting the bonding material 300 include corrosive substances (Na, K) in order to enhance the sealing function of the bonding material 300. This is because when the bonding material 300 contains a corrosive substance, the “wetting property” of the bonding material 300 (more specifically, the paste that is a precursor of the bonding material 300) is increased, and the bonding material 300 is bonded. This is based on the increased adhesion of the part (surface).

  However, when a substance containing a corrosive substance is used as the material of the bonding material 300, the corrosive substance evaporates from the bonding material 300 at the operating temperature of the fuel cell, and the evaporated corrosive substance is “a space through which the fuel gas passes. "Stainless steel member facing the surface" (for example, the inner wall of the manifold 200) and "Stainless steel member facing the space through which air passes" (for example, the outer wall of the manifold 200, the current collecting member 400, etc.) Can reach. When the corrosive substance reaches the stainless steel member, there may be a problem that the stainless steel member is easily corroded.

  Therefore, as shown in FIG. 21, in this stack structure, the “surface facing the inner space of the manifold 200” in the bonding material 300 (in other words, the space facing the fuel gas during operation of the SOFC). The surface) is covered with a film (coating film) 310 made of a substance not containing a corrosive substance. In addition, this “surface” can also be described as “a surface exposed to fuel gas during operation of the fuel cell when it is assumed that the coating film 310 is not covered”. Similarly, the “surface facing the external space of the manifold 200” (in other words, the surface facing the space through which air passes during operation of the SOFC) in the bonding material 300 is composed of a substance that does not contain a corrosive substance. It is covered with a film (coating film) 320. This “surface” can also be described as “a surface exposed to air during operation of the fuel cell when it is assumed that the coating film 320 is not covered”.

The coating films 310 and 320 can be made of crystallized glass that does not contain a corrosive substance such as SiO ₂ —ZnO—BaO—La ₂ O ₃ or SiO ₂ —ZnO—BaO. The materials constituting the coating films 310 and 320 may be the same or different. The coating films 310 and 320 may be dense or porous. The thickness of the coating films 310 and 320 is 5 to 50 μm. The coating films 310 and 320 are formed on the surface of the solidified and ceramicized bonding material 300 by using a spray method, a brush coating method, or the like using a paste film containing the material of the coating films 310 and 320. It can be formed by applying heat treatment to the formed paste film.

(Operation and effect by providing coating films 310 and 320)
As described above, in the SOFC stack structure according to the embodiment of the present invention, the “surface facing the space through which the fuel gas passes” in the bonding material 300 is covered with the coating film 310 made of a substance not containing a corrosive substance. . Therefore, the phenomenon that “corrosive substances evaporated from the same surface of the bonding material reach the stainless steel member that faces the space through which the fuel gas passes” described in the “Summary of Invention” section can occur. No (or less likely to occur). As a result, the problem of “corrosion of the stainless steel member facing the space through which the fuel gas passes” does not occur (or is difficult to occur).

  Further, the “surface facing the space through which air passes” in the bonding material 300 is covered with a coating film 320 made of a substance that does not contain a corrosive substance. As a result, the problem of “corrosion of the stainless steel member facing the space through which air passes” does not occur (or is difficult to occur).

  In addition, the bonding material 300 itself is composed of a substance containing a corrosive substance. Therefore, by improving the “wetting property” of the bonding material 300 (a paste which is a precursor thereof), the adhesion of the portion bonded by the bonding material 300 is increased. As described above, according to the SOFC stack structure according to the embodiment of the present invention, the “stainless steel member” included in the stack structure is maintained while maintaining good adhesion between the cell 100 and the support plate 210 (partition member). It becomes difficult to be corroded.

  In the embodiment (see FIG. 21), the volume occupied by the substance containing the corrosive substance (bonding material 300) is larger than the volume occupied by the film of the substance not containing the corrosive substance (coating films 310 and 320). On the other hand, the volume occupied by the substance containing the corrosive substance (bonding material 300) may be smaller than the volume occupied by the film of the substance not containing the corrosive substance (coating films 310 and 320).

  Hereinafter, the test performed in order to confirm the operation | movement and effect mentioned above by providing the coating films 310 and 320 in the joining material 300 is demonstrated.

(test)
In this test, the material of the bonding material 300, the material of the coating films 310 and 320, the thickness (μm) of the coating films 310 and 320, and the coating film 310 of the SOFC stack structure shown in FIGS. , 320 samples having different porosity (volume%) combinations were produced. Specifically, as shown in Table 1, 11 types of levels were prepared. One sample (stack structure) was made for each level. In levels 4 to 11, both coating films 310 and 320 are provided, but in level 1 both coating films 310 and 320 are not provided. In level 2, only the coating film 310 is provided, and the coating film 320 is not provided. In level 3, only the coating film 320 is provided, and the coating film 310 is not provided.

  For each sample (stack structure), the number of stacks (number of cells 100) was 5. The cell 100 had a thin plate shape with a length (x-axis direction) L1 of 50 to 500 mm, a width (y-axis direction) L2 of 10 to 100 mm, and a thickness (z-axis direction) L3 of 1 to 5 mm (see FIG. 1 and FIG. 19). The length (x-axis direction) L4 of each insertion hole 211 formed in the support plate 210 of the manifold 200 is 0.2 to 3 mm larger than the width L2 of the cell 100, and the width (z-axis direction) L5 of each insertion hole 211. Was 0.2-3 mm larger than the thickness L3 of the cell 100 (see FIG. 19). The rectangular parallelepiped manifold 200 and the current collecting member 400 that electrically connects the adjacent cells 100 are made of stainless steel. That is, at least the manifold 200 and the current collecting member 400 correspond to “stainless steel members”.

  The particle size of the ceramic powder contained in the paste for the bonding material 300 was 0.3 to 2.5 μm. The heat treatment applied to solidify and ceramicize this paste was performed at 800 to 1100 ° C. for 1 to 10 hours. The solidified and ceramicized bonding material 300 was dense, and the content of corrosive substances in the bonding material 300 was 5 to 40% by weight.

  The coating films 310 and 320 are formed on the surface of the solidified and ceramicized bonding material 300 by using a spray method, a brush coating method, or the like using a paste film containing the material of the coating films 310 and 320. The paste film thus formed was formed by applying a heat treatment. This heat treatment was performed at 800-1100 ° C. for 1-10 hours. The average value of the diameters of the pores existing in the coating films 310 and 320 was 0.5 to 5 μm. The entire region of the “surface facing the internal space of the manifold 200” in the bonding material 300 was covered with the coating film 310. Similarly, the entire “surface facing the external space of the manifold 200” in the bonding material 300 was covered with the coating film 320.

  For each of the levels 4 to 11, the material, thickness, and porosity were the same between the coating films 310 and 320. For each level, the thickness of the coating films 310 and 320 was adjusted by changing the number of repetitions of spraying or brushing. The porosity of the coating films 310 and 320 is adjusted by adjusting the particle diameter of the material included in the paste for the coating films 310 and 320 and the particle diameter of the pore former (typically PMMA, carbon particles, etc.). Made by doing. When film formation is performed in a state where bubbles are mixed in the paste, a large pore of about 100 μm may be formed. In order to prevent the formation of such large pores, it is desirable to remove bubbles in the paste using a vacuum defoaming device or the like before film formation.

  As the “thickness” of the coating films 310 and 320, an average value of thicknesses at three predetermined positions in each film was used.

  The “porosity” and “average value of pore diameter” of the coating films 310 and 320 were calculated as follows. First, a so-called “resin filling” process was performed on the membrane so that the resin entered the pores of the membrane. The surface of the “resin-filled” film was mechanically polished. By performing image processing on the image obtained by observing the microstructure of the mechanically polished surface using a scanning electron microscope, the area of each pore portion (portion where the resin enters) is reduced. Calculated. From the area of each pore portion, the equivalent diameter of each pore was calculated. The average value of the equivalent diameters was defined as the “average value of pore diameter” (μm) of the membrane. Further, the ratio of “the total area of the pores” to “the total area of the mechanically polished surface” was defined as the “porosity” (volume%) of the film. In addition, as the “porosity” and “average value of pore diameter” of the film, the average value of values obtained respectively from the surfaces of a plurality of places (for example, three places) mechanically polished is adopted. Is preferred.

  In this test, each sample was subjected to a durability test for evaluating the progress of corrosion of the stainless steel member in a high temperature atmosphere of 800 ° C. while maintaining a constant current. Specifically, the occurrence of corrosion of the stainless steel member after 1000 hours was evaluated by visual observation or the like. The evaluation results are shown in Table 1 above. In this test, “when it is recognized that corrosion is occurring violently” is evaluated as rejected (×), and “when it is determined that corrosion has occurred slightly or has not occurred” is passed (○ Or ◎). Among the passing results, the “when it is recognized that corrosion has not occurred” was the best (◎). The level 11 is evaluated as “best” considering only the occurrence of corrosion, but the reason is unknown, but slight cracks have occurred in the coating films 310 and 320. Therefore, it was generally evaluated as a pass (◯).

  As is clear from Table 1, when at least one of the coating films 310 and 320 is provided (see levels 2 to 11), compared to a case where both the coating films 310 and 320 are not provided (see level 1). The progress of corrosion of the stainless steel member (specifically, the manifold 200 or the current collecting member 400) is small. This is considered to be due to the fact that the amount of the corrosive substance evaporated from the bonding material 300 reaches the stainless steel member decreases due to the presence of at least one of the coating films 310 and 320.

  In addition, when the thickness of the coating films 310 and 320 is 1 to 10 μm and the porosity of the coating films 310 and 320 is 10 to 40% by volume (see levels 4 to 10), the coating film 310, In addition to being hard to generate cracks at 320, the stainless steel member does not corrode after the endurance test.

  The present invention is not limited to the above embodiment, and various modifications can be employed within the scope of the present invention. For example, in the above-described embodiment, the entire area of the “surface facing the internal space of the manifold 200” (in other words, the surface facing the space through which the fuel gas passes during operation of the SOFC) in the bonding material 300 is the coating film 310. However, only a part of the surface may be covered with the coating film 310, and the remaining part other than the part of the surface may be exposed to the internal space of the manifold 200. Similarly, the entire region of the “surface facing the external space of the manifold 200” (in other words, the surface facing the space through which air passes during operation of the SOFC) in the bonding material 300 is covered with the coating film 320. However, only a part of the surface may be covered with the coating film 320, and the remaining part of the surface other than the part may be exposed to the external space of the manifold 200.

  In the above embodiment, one end of the cell 100 itself is bonded to the support plate 210 using the bonding material 300, but the electrode terminal provided at one end of the cell 100 is supported to the support plate using the bonding material 300. 210 may be joined.

  Moreover, in the said embodiment, although the one end part of one cell 100 is inserted in one insertion hole 211 formed in the support plate 210, as shown in FIG. One end of two or more cells 100 may be inserted into the insertion hole 211. In FIG. 22, the interval between adjacent cells 100 is exaggerated. Further, all of one end portions of the plurality of cells 100 may be inserted into one (only) insertion hole 211 formed in the support plate 210.

  In the above embodiment, one end of the cell 100 is inserted into the insertion hole 211 (that is, one end of the cell 100 enters the internal space of the insertion hole 211) (see FIG. 18 and the like). 23, one end of the cell 100 may not be inserted into the hole 211 (that is, the one end of the cell 100 may not enter the internal space of the hole 211). In this case, the bonding material 300 is provided so as to fill a space existing between the hole 211 and one end of the cell 100 at each of the bonding portions between the holes 211 and the corresponding one end of the cell 100. In addition, as in the above embodiment, in the example shown in FIG. 23, as shown in FIG. 24, the “surface facing the internal space of the manifold 200” in the bonding material 300 (in other words, during operation of the SOFC). The surface facing the space through which the fuel gas passes is covered with a coating film 310 containing no corrosive substance. Furthermore, the “surface facing the external space of the manifold 200” in the bonding material 300 (in other words, the surface facing the space through which air passes during operation of the SOFC) is the coating film 320 that does not contain a corrosive substance. Covered.

  In the above embodiment, the top plate of the manifold also serves as a support plate for supporting a large number of cells (that is, the support plate is integrally formed with the manifold). As long as the gas flow paths of the cells communicate with each other, the support plate may be configured separately from the manifold.

  In addition, as shown in FIG. 25, the present invention provides a “flat cell comprising a fuel electrode, an air electrode, and a solid electrolyte positioned between the fuel electrode and the air electrode” and an “interconnector”. (Corresponding to the “partition member”) can be applied to a stack structure of a fuel cell in which are alternately stacked. Usually, the “interconnector” is made of stainless steel. In this case, as shown in FIG. 26, each cell is joined to each of the end portions of the interconnector adjacent to the top and bottom of the cell using a joining material 300 (including a corrosive substance). Then, the “surface facing the fuel gas flow path” (in other words, the surface facing the space through which the fuel gas passes during operation of the fuel cell) in the bonding material 300 is the coating film 310 that does not contain a corrosive substance. Covered. Furthermore, the “surface facing the air flow path” of the bonding material 300 (in other words, the surface facing the space through which air passes during operation of the fuel cell) is covered with the coating film 320 containing no corrosive substance. It has been broken. Due to the presence of these coating films 310 and 320, the progress of corrosion of the stainless steel member (= interconnector) is reduced.

  DESCRIPTION OF SYMBOLS 10 ... Support substrate, 11 ... Fuel gas flow path, 20 ... Fuel electrode, 40 ... Solid electrolyte membrane, 60 ... Air electrode, A ... Power generation element part, 100 ... Cell, 200 ... Manifold, 210 ... Support plate, 211 ... Insertion Hole 300, bonding material, 310 ... coating film, 320 ... coating film

Claims (16)

A cell including a fuel electrode, an air electrode, and a solid electrolyte positioned between the fuel electrode and the air electrode;
A partition member for preventing mixing of the cell and a fuel gas supplied to the fuel electrode and a gas containing oxygen supplied to the air electrode, which is joined to the cell using a joining material A partition member;
A fuel cell structure comprising:
The bonding material is composed of a substance containing an alkali metal, and the surface of the bonding material facing the space through which the fuel gas passes during operation of the fuel cell does not contain the alkali metal. A fuel cell structure covered with a membrane. Each includes a support substrate having a longitudinal direction and a gas flow path along the longitudinal direction formed therein, and at least a fuel electrode, a solid electrolyte, and an air electrode provided on the surface of the support substrate in this order. A plurality of cells including:
Each cell is joined to each other using a joining material so that each cell protrudes from the surface of the support plate along the longitudinal direction and the plurality of cells are arranged in a stack. A supporting plate to support;
A gas manifold provided with the support plate so that the internal space of the manifold communicates with one end of each of the gas flow paths of the plurality of cells;
A fuel cell stack structure comprising:
One or a plurality of holes for communicating the internal space of the manifold and one end of the plurality of cells are formed on the surface of the support plate,
One end of each cell is positioned corresponding to the corresponding hole;
The bonding material is provided so as to fill a space existing between the hole and one end of the cell at each of the bonding portions between the holes and the corresponding one end of the cell. The hole and the corresponding one end of the cell are joined together,
The bonding material is made of a substance containing an alkali metal, and a space in the bonding material through which the fuel gas supplied to the gas flow path through the manifold during operation of the fuel cell passes. A stack structure of a fuel cell, wherein a facing surface is covered with a film of a substance not containing an alkali metal . Each includes a support substrate having a longitudinal direction and a gas flow path along the longitudinal direction formed therein, and at least a fuel electrode, a solid electrolyte, and an air electrode provided on the surface of the support substrate in this order. A plurality of cells including:
Each cell is joined to each other using a joining material so that each cell protrudes from the surface of the support plate along the longitudinal direction and the plurality of cells are arranged in a stack. A supporting plate to support;
A gas manifold provided with the support plate so that the internal space of the manifold communicates with one end of each of the gas flow paths of the plurality of cells;
A fuel cell stack structure comprising:
On the surface of the support plate, a plurality of insertion holes for communicating with the internal space of the manifold and inserting one end portions of the plurality of cells are formed.
One end of each cell is loosely fitted into the corresponding insertion hole,
The bonding material is provided so as to enter at least a gap existing between the inner wall of the insertion hole and the outer wall of the one end of the cell at each of the bonding portions between the insertion holes and the corresponding one end of the cell. The one end of each cell corresponding to each insertion hole is joined,
The bonding material is made of a substance containing an alkali metal, and a space in the bonding material through which the fuel gas supplied to the gas flow path through the manifold during operation of the fuel cell passes. A stack structure of a fuel cell, wherein a facing surface is covered with a film of a substance not containing an alkali metal . A cell including a fuel electrode, an air electrode, and a solid electrolyte positioned between the fuel electrode and the air electrode;
A partition member for preventing mixing of the cell and a fuel gas supplied to the fuel electrode and a gas containing oxygen supplied to the air electrode, which is joined to the cell using a joining material A partition member;
A fuel cell structure comprising:
The bonding material is composed of a substance containing an alkali metal, and a surface of the bonding material facing a space through which the gas containing oxygen passes during operation of the fuel cell contains the alkali metal . A fuel cell structure covered with a film of non-performing material. Each includes a support substrate having a longitudinal direction and a gas flow path along the longitudinal direction formed therein, and at least a fuel electrode, a solid electrolyte, and an air electrode provided on the surface of the support substrate in this order. A plurality of cells including:
Each cell is joined to each other using a joining material so that each cell protrudes from the surface of the support plate along the longitudinal direction and the plurality of cells are arranged in a stack. A supporting plate to support;
A gas manifold provided with the support plate so that the internal space of the manifold communicates with one end of each of the gas flow paths of the plurality of cells;
A fuel cell stack structure comprising:
One or a plurality of holes for communicating the internal space of the manifold and one end of the plurality of cells are formed on the surface of the support plate,
One end of each cell is positioned corresponding to the corresponding hole;
The bonding material is provided so as to fill a space existing between the hole and one end of the cell at each of the bonding portions between the holes and the corresponding one end of the cell. The hole and the corresponding one end of the cell are joined together,
The bonding material, while being constituted by a material containing an alkali metal, in the bonding material, the surface of a gas containing oxygen Te during operation of the fuel cell is directed into the space passes through, containing the alkali metal A stack structure of a fuel cell, covered with a film of non-conducting material. Each includes a support substrate having a longitudinal direction and a gas flow path along the longitudinal direction formed therein, and at least a fuel electrode, a solid electrolyte, and an air electrode provided on the surface of the support substrate in this order. A plurality of cells including:
Each cell is joined to each other using a joining material so that each cell protrudes from the surface of the support plate along the longitudinal direction and the plurality of cells are arranged in a stack. A supporting plate to support;
A gas manifold provided with the support plate so that the internal space of the manifold communicates with one end of each of the gas flow paths of the plurality of cells;
A fuel cell stack structure comprising:
On the surface of the support plate, a plurality of insertion holes for communicating with the internal space of the manifold and inserting one end portions of the plurality of cells are formed.
One end of each cell is loosely fitted into the corresponding insertion hole,
The bonding material is provided so as to enter at least a gap existing between the inner wall of the insertion hole and the outer wall of the one end of the cell at each of the bonding portions between the insertion holes and the corresponding one end of the cell. The one end of each cell corresponding to each insertion hole is joined,
The bonding material, while being constituted by a material containing an alkali metal, in the bonding material, the surface of a gas containing oxygen Te during operation of the fuel cell is directed into the space passes through, containing the alkali metal A stack structure of a fuel cell, covered with a film of non-conducting material. The fuel cell structure according to any one of claims 1 to 6, wherein
The membrane of the substance containing no alkali metal is a porous membrane,
A structure of a fuel cell, wherein the thickness of the membrane is 1 to 10 μm, and the porosity of the membrane is 10 to 40% by volume. In the structure of the fuel cell according to any one of claims 1 to 7,
The substance containing the alkali metal is crystallized glass having a crystallinity of 60% or more,
The structure of a fuel cell, wherein the substance not containing an alkali metal is also a crystallized glass having a crystallinity of 60% or more.   A cell including a fuel electrode, an air electrode, and a solid electrolyte positioned between the fuel electrode and the air electrode;
  A partition member for preventing mixing of the cell and a fuel gas supplied to the fuel electrode and a gas containing oxygen supplied to the air electrode, which is joined to the cell using a joining material A partition member;
  A fuel cell structure comprising:
  The bonding material is glass, and is composed of a substance containing a corrosive substance that evaporates from the bonding material and corrodes stainless steel at the operating temperature of the fuel cell, and in the operation of the fuel cell in the bonding material. A structure of a fuel cell, wherein a surface facing a space through which the fuel gas passes is covered with a film of a substance not containing a corrosive substance.   Each includes a support substrate having a longitudinal direction and a gas flow path along the longitudinal direction formed therein, and at least a fuel electrode, a solid electrolyte, and an air electrode provided on the surface of the support substrate in this order. A plurality of cells including:
  Each cell is joined to each other using a joining material so that each cell protrudes from the surface of the support plate along the longitudinal direction and the plurality of cells are arranged in a stack. A supporting plate to support;
  A gas manifold provided with the support plate so that the internal space of the manifold communicates with one end of each of the gas flow paths of the plurality of cells;
  A fuel cell stack structure comprising:
  One or a plurality of holes for communicating the internal space of the manifold and one end of the plurality of cells are formed on the surface of the support plate,
  One end of each cell is positioned corresponding to the corresponding hole;
  The bonding material is provided so as to fill a space existing between the hole and one end of the cell at each of the bonding portions between the holes and the corresponding one end of the cell. The hole and the corresponding one end of the cell are joined together,
  The bonding material is glass, and is composed of a substance containing a corrosive substance that evaporates from the bonding material and corrodes stainless steel at the operating temperature of the fuel cell, and in the operation of the fuel cell in the bonding material. A fuel cell stack structure in which a surface facing a space through which fuel gas supplied to the gas flow path through the manifold passes is covered with a film of a substance not containing a corrosive substance.   Each includes a support substrate having a longitudinal direction and a gas flow path along the longitudinal direction formed therein, and at least a fuel electrode, a solid electrolyte, and an air electrode provided on the surface of the support substrate in this order. A plurality of cells including:
  Each cell is joined to each other using a joining material so that each cell protrudes from the surface of the support plate along the longitudinal direction and the plurality of cells are arranged in a stack. A supporting plate to support;
  A gas manifold provided with the support plate so that the internal space of the manifold communicates with one end of each of the gas flow paths of the plurality of cells;
  A fuel cell stack structure comprising:
  On the surface of the support plate, a plurality of insertion holes for communicating with the internal space of the manifold and inserting one end portions of the plurality of cells are formed.
  One end of each cell is loosely fitted into the corresponding insertion hole,
  The bonding material is provided so as to enter at least a gap existing between the inner wall of the insertion hole and the outer wall of the one end of the cell at each of the bonding portions between the insertion holes and the corresponding one end of the cell. The one end of each cell corresponding to each insertion hole is joined,
  The bonding material is glass, and is composed of a substance containing a corrosive substance that evaporates from the bonding material and corrodes stainless steel at the operating temperature of the fuel cell, and in the operation of the fuel cell in the bonding material. A fuel cell stack structure in which a surface facing a space through which fuel gas supplied to the gas flow path through the manifold passes is covered with a film of a substance not containing a corrosive substance.   A cell including a fuel electrode, an air electrode, and a solid electrolyte positioned between the fuel electrode and the air electrode;
  A partition member for preventing mixing of the cell and a fuel gas supplied to the fuel electrode and a gas containing oxygen supplied to the air electrode, which is joined to the cell using a joining material A partition member;
  A fuel cell structure comprising:
  The bonding material is glass, and is composed of a substance containing a corrosive substance that evaporates from the bonding material and corrodes stainless steel at the operating temperature of the fuel cell, and in the operation of the fuel cell in the bonding material. A structure of a fuel cell, wherein a surface facing a space through which the gas containing oxygen passes is covered with a film of a substance not containing a corrosive substance.   Each includes a support substrate having a longitudinal direction and a gas flow path along the longitudinal direction formed therein, and at least a fuel electrode, a solid electrolyte, and an air electrode provided on the surface of the support substrate in this order. A plurality of cells including:
  Each cell is joined to each other using a joining material so that each cell protrudes from the surface of the support plate along the longitudinal direction and the plurality of cells are arranged in a stack. A supporting plate to support;
  A gas manifold provided with the support plate so that the internal space of the manifold communicates with one end of each of the gas flow paths of the plurality of cells;
  A fuel cell stack structure comprising:
  One or a plurality of holes for communicating the internal space of the manifold and one end of the plurality of cells are formed on the surface of the support plate,
  One end of each cell is positioned corresponding to the corresponding hole;
  The bonding material is provided so as to fill a space existing between the hole and one end of the cell at each of the bonding portions between the holes and the corresponding one end of the cell. The hole and the corresponding one end of the cell are joined together,
  The bonding material is glass, and is composed of a substance containing a corrosive substance that evaporates from the bonding material and corrodes stainless steel at the operating temperature of the fuel cell. A fuel cell stack structure in which a surface facing a space through which a gas containing oxygen passes is covered with a film of a substance not containing a corrosive substance.   Each includes a support substrate having a longitudinal direction and a gas flow path along the longitudinal direction formed therein, and at least a fuel electrode, a solid electrolyte, and an air electrode provided on the surface of the support substrate in this order. A plurality of cells including:
  Each cell is joined to each other using a joining material so that each cell protrudes from the surface of the support plate along the longitudinal direction and the plurality of cells are arranged in a stack. A supporting plate to support;
  A gas manifold provided with the support plate so that the internal space of the manifold communicates with one end of each of the gas flow paths of the plurality of cells;
  A fuel cell stack structure comprising:
  On the surface of the support plate, a plurality of insertion holes for communicating with the internal space of the manifold and inserting one end portions of the plurality of cells are formed.
  One end of each cell is loosely fitted into the corresponding insertion hole,
  The bonding material is provided so as to enter at least a gap existing between the inner wall of the insertion hole and the outer wall of the one end of the cell at each of the bonding portions between the insertion holes and the corresponding one end of the cell. The one end of each cell corresponding to each insertion hole is joined,
  The bonding material is glass, and is composed of a substance containing a corrosive substance that evaporates from the bonding material and corrodes stainless steel at the operating temperature of the fuel cell. A fuel cell stack structure in which a surface facing a space through which a gas containing oxygen passes is covered with a film of a substance not containing a corrosive substance.   The structure of the fuel cell according to any one of claims 9 to 14,
  The film of the substance not containing the corrosive substance is a porous film,
  A structure of a fuel cell, wherein the thickness of the membrane is 1 to 10 μm, and the porosity of the membrane is 10 to 40% by volume.   The fuel cell structure according to any one of claims 9 to 15,
  The substance containing the corrosive substance is crystallized glass having a crystallinity of 60% or more,
  The structure of a fuel cell, wherein the substance not containing the corrosive substance is also a crystallized glass having a crystallinity of 60% or more.