JP2008135272A - Inter-connector of planar fuel cell, manufacturing method thereof, planar fuel cell, planar fuel cell stack, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inter-connector of a planar fuel cell capable of preventing gas leakage from a gas channel, as well as its manufacturing method, to provide a planar fuel cell, to provide a planar fuel cell stack, and to provide a manufacturing method thereof. <P>SOLUTION: A planar fuel battery cell in which electrodes are provided on both sides of a solid electrolyte and an inter-connector 5 which is connected to one electrode 3a, with a gas supply channel 7a formed at the electrode 3a, are alternately stacked. The planar fuel battery cell and the inter-connector 5 are simultaneously baked, and fillet parts S<SB>1</SB>and S<SB>2</SB>are formed at the corners of the gas channel 7a. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an interconnector having a recess for forming a gas passage, a manufacturing method thereof, a flat plate fuel cell in which an interconnector is stacked on a flat plate fuel cell, and a flat plate fuel cell and an interconnector. The present invention relates to a flat plate fuel cell stack that is alternately stacked and a method for manufacturing the same.

  As conventional fuel cells, cylindrical fuel cells and hollow plate fuel cells are known, and these are prepared by extrusion molding a cylindrical or hollow plate type support. It was produced by laminating an electrode compact and a solid electrolyte compact on the surface of the compact and firing it.

Further, as a conventional flat plate fuel cell, a method is known in which a plurality of sheets are laminated to produce a laminated molded body and the laminated molded body is fired (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 2003-297387

  In Patent Document 1, in order to produce a flat plate fuel cell, unsintered sheets are laminated, and polyethylene or carbon black is printed and formed on a portion where a gas passage is formed. Although it is described that a passage is formed, in such a sheet laminating method, cracks are likely to enter from the corners of the gas passage, and even if cracks do not occur at the time of production, cracks are caused by long-term power generation and progress. However, there is a risk of gas leakage from the gas passage.

  In general, when a substrate is produced by a sheet lamination method, in order to improve the adhesion between unsintered sheets, it is pressed and pressed in the thickness direction. At this time, a space for forming a gas passage is used. In the sheet stacking direction, the side surface of the central part of the sheet tends to protrude inward (scattering material side), peeling occurs at the corners of the space that forms the gas passage, gaps are formed, and cracks are generated from the corners during power generation. As a result, gas leakage may occur from the gas passage.

  An object of the present invention is to provide a flat plate fuel cell interconnector capable of preventing gas leakage from a gas passage and a method of manufacturing the same, a flat plate fuel cell, a flat plate fuel cell stack, and a method of manufacturing a flat plate fuel cell stack. And

  The interconnector of the flat plate fuel cell of the present invention has a recess for forming a gas passage, and is formed by laminating and firing a plurality of unsintered tapes containing interconnector material powder. A fillet portion is formed in the portion.

  In such an interconnector of a flat plate fuel cell, a fillet portion is formed at the corner of the recess for forming the gas passage, so that the occurrence of cracks at the corner of the gas passage is suppressed when the interconnector is manufactured. In addition, the generation and development of cracks from the corners can be prevented even by power generation for a long time, and gas leakage from the gas passage can be prevented.

  Further, the method for producing an interconnector for a flat plate fuel cell according to the present invention is a method for producing an interconnector for a flat plate fuel cell having a recess for forming a gas passage, and has a through-hole in the thickness direction. A plurality of unsintered tapes containing powder are formed, and a fillet portion is formed at the corners of the recesses in the recesses of the gas passage shape formed by the through holes of the unsintered tapes. An interconnector molded body containing a gas passage forming material composed of an inorganic material to be formed and a disappearing substance that disappears upon firing is formed through a firing step.

  According to such a manufacturing method, since the gas passage forming material composed of the inorganic material and the scattering material is accommodated in the recess of the gas passage shape of the interconnector molded body, when the interconnector molded body is fired, the gas passage formation is performed. The scattering material in the material is scattered, and the inorganic material is gathered by capillarity in the corners of the recesses, particularly in the gaps (peeling parts) formed at the time of pressurization of the interconnector molded body, and fired. Thus, the fillet portion can be formed, and the corners of the recesses can be rounded. Thereby, generation | occurrence | production of the crack at the time of cell preparation can be prevented, and also progress of the crack from a corner | angular part can be prevented by a fillet part.

  Further, the flat plate fuel cell of the present invention forms a gas passage for connecting to one of the electrodes and supplying gas to the flat plate fuel cell having electrodes provided on both sides of the solid electrolyte. A flat plate fuel cell in which interconnectors are stacked, wherein the solid electrolyte, the one electrode, and the interconnector are formed by simultaneous firing, and a fillet portion is formed at a corner of the gas passage. It is characterized by being.

  In such a flat plate fuel cell, the fillet portion is formed at the corner of the gas passage, so that the generation of cracks at the corner of the gas passage can be suppressed during the production of the flat plate fuel cell, and the power generation for a long time Also, the occurrence and development of cracks from the corners can be prevented, and gas leakage from the gas passage can be prevented. The interconnector includes a case where it is formed by laminating a plurality of unsintered tapes containing interconnector material powder, and a case where it is formed by press molding.

  The flat plate fuel cell of the present invention is characterized in that a fillet portion is formed at a corner portion of the gas passage formed by the one electrode and the interconnector. In such a flat plate fuel cell, it is possible to suppress the occurrence of cracks at the corners of the gas passage formed by one electrode and the interconnector, and further, the generation and progress of cracks from the corners even when power is generated for a long time. Can be prevented.

  The flat plate fuel cell of the present invention is characterized in that the gas passage is formed by an electrode to which the interconnector is connected and a recess formed on the electrode side of the interconnector.

  The flat plate fuel cell stack according to the present invention includes a flat plate fuel cell having electrodes provided on both sides of a solid electrolyte, and an interface that is connected to one of the electrodes and forms a gas passage for supplying gas to the electrode. It is formed by alternately laminating connectors, the flat fuel cell and the interconnector are formed by simultaneous firing, and a fillet portion is formed at a corner of the gas passage. . In such a flat fuel cell stack, the generation of cracks at the corners of the gas passages can be suppressed during the production of the cell stack, and the generation and development of cracks from the corners can be prevented even by long-time power generation. Gas leakage from the passage can be prevented.

  The method for producing a flat plate fuel cell stack according to the present invention includes a fuel cell molded body in which electrode molded bodies are provided on both sides of a solid electrolyte molded body, and an interconnector molded body, which are alternately stacked, Forming a stack molded body containing a gas passage forming material composed of an inorganic material and a scattered substance scattered during firing in a recess formed on the one electrode molded body side of the connector molded body through a firing step. It is characterized by.

  In such a method for manufacturing a flat plate fuel cell stack, a gas passage forming material composed of an inorganic material and a scattered substance is accommodated in a recess in the gas passage shape of the interconnector molded body. As the scattering material inside is scattered, the inorganic material gathers by capillary action at the corners of the gas passages, particularly in the gaps (peeling portions) formed at the time of pressurization of the stack molded body. A fillet portion can be formed, and the corners of the gas passage can be rounded. Thereby, generation | occurrence | production of the crack at the time of stack preparation can be prevented, and also generation | occurrence | production and progress of the crack from a corner | angular part can be prevented by a fillet part.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the flat plate fuel cell stack of the present invention includes a porous gas-permeable conductive support 3a, a porous fuel-side electrode 3b, a dense plate-shaped solid electrolyte 3c, a porous The flat fuel cell 3 and the interconnector 5 are formed by alternately stacking the oxygen-side electrodes 3d.

  On the surface of the interconnector 5 on the support 3a side and on the oxygen side electrode 3d side, recesses 5a and 5b having a rectangular cross section are formed. The recesses 5a and 5b, the support 3a, and the oxygen side electrode 3d A fuel gas passage 7a and an oxygen-containing gas passage 7b are respectively formed. A fuel gas introduction port 8 for introducing fuel gas into the fuel cell 3 is formed at one end of the fuel gas passage 7a, and a fuel gas discharge port (not shown) is formed at the other end. Is formed. An oxygen-containing gas inlet (not shown) is formed at one end of the oxygen-containing gas passage 7b, and an oxygen-containing gas discharge port 9 is formed at the other end.

  The fuel gas introduced into the fuel gas passage 7a from the fuel gas inlet 8 diffuses from the surface of the support 3a into the support 3a and further reaches the fuel side electrode 3b. Further, the oxygen-containing gas introduced from the oxygen-containing gas inlet into the oxygen-containing gas passage 7b is supplied to the oxygen-side electrode 3d. In this way, the fuel gas and the oxygen-containing gas supplied to the fuel-side electrode 3b and the oxygen-side electrode 3d facing each other through the solid electrolyte 3c cause an electrochemical reaction to generate power. Excess fuel gas and oxygen-containing gas are discharged from a fuel gas outlet (not shown) and an oxygen-containing gas outlet 9, respectively.

  The flat plate fuel cell apparatus is configured by providing a manifold in such a flat plate fuel cell stack.

  That is, as shown in FIG. 2, in the flat plate fuel cell device, an air supply side gas pipe 13 for introducing an oxygen-containing gas from the outside into the plurality of fuel cells 3 is connected to the air supply side manifold 15. The air supply side manifold 15 has an air supply side gas chamber 19 for introducing gas to gas inlets formed on the air supply side manifold 15 side of the interconnector 5 disposed between the plurality of flat plate fuel cells 3. Is formed.

  An oxygen-containing gas discharge port 9 for discharging gas is formed at the other end of the interconnector 5, and an exhaust side manifold 23 and an exhaust side gas pipe for discharging the exhausted gas to the outside of the fuel cell device. 25 is arranged. An exhaust side gas chamber 27 for collecting exhaust gas is formed in the exhaust side manifold 23. In addition, an oxygen-containing gas passage 7 b that communicates from the gas inlet 17 to the gas outlet 9 is formed in the interconnector 5 disposed between the flat fuel cells 3. A fuel gas passage 7 a for supplying fuel gas to the flat plate fuel cell 3 is formed in a direction orthogonal to the oxygen-containing gas passage 7 b of the interconnector 5.

  The flat plate fuel cell 3 generally has a rectangular plate shape, and the air supply side manifold 15 and the exhaust side manifold 23 shown in FIG. 2 supply oxygen-containing gas to the flat plate fuel cell 3 for exhaust. A gas supply side manifold (not shown) and an exhaust side manifold (not shown) for supplying and exhausting fuel gas in a direction perpendicular to the oxygen-containing gas. .

  The periphery of the flat fuel cell 3 is sealed with a gas seal layer 31.

  In such a flat plate fuel cell device, an oxygen-containing gas is supplied to the supply side manifold 15 shown in FIG. 2 and a gas introduction formed at one end of the interconnector 5 through the supply side gas chamber 19. The gas is guided to the port 17 and passes through the oxygen-containing gas passage 7b formed on the surface of the interconnector 5 in contact with the oxygen side electrode 3d. The gas that has passed through the oxygen-containing gas passage 7 b is led from the gas discharge port 9 formed at the other end of the interconnector 5 to the exhaust side gas chamber 27 formed in the exhaust side manifold 23, and the exhaust side gas pipe 25. Is exhausted to the outside of the fuel cell device.

  At the same time, the fuel gas is supplied to the other supply side manifold (not shown), and is passed through the fuel gas passage 7a formed on the surface of the interconnector 5 in contact with the fuel side electrode 3b. The fuel gas that has passed through the fuel gas passage 7a is led to an exhaust side gas chamber (not shown) formed in an exhaust side manifold (not shown), and the fuel gas passes through an exhaust side gas pipe (not shown). It is exhausted out of the battery device.

  The fuel gas and the oxygen-containing gas follow the above path and are supplied to the flat plate fuel cell 3 and discharged. At this time, the fuel gas supplied to the fuel-side electrode 3b of the flat fuel cell 3 and the oxygen-containing gas supplied to the oxygen-side electrode 3d cause an electrochemical reaction to generate power.

The gas passages 7a and 7b are rectangular in cross section as shown in FIG. 3, and fillet portions S ₁ and S ₂ are formed at the corners, and the corners of the gas passages 7a and 7b are formed. It is rounded. That is, the concave portion 5a of the interconnector 5, walled portion S ₁ corner to corner of the 5b are formed, the recess 5a, meat section S ₂ also corners in the corners formed by 5b and the support 3a is formed . In FIG. 3, the material forming the fillet portions S ₁ and S ₂ adheres not only to the four corners of the gas passages 7a and 7b, but also to the corner portions of the side surfaces thereof. The adhesion of the fillet portion materials of the fillet portions S ₁ and S ₂ and the side corner portions can be controlled by the content ratio of the inorganic material in the gas passage forming material described later. That is, when the inorganic material in the gas passage forming material is large, not only the four corners of the gas passages 7a and 7b but also the corner portions of the side surfaces are formed with the forming materials of the fillet portions S ₁ and S ₂ , When the shape of the passage approaches a circular cross section and is small, fillet portions S ₁ and S ₂ are formed mainly at the four corners of the gas passages 7a and 7b.

The fillet portions S ₁ and S ₂ are preferably made of a material that forms the interconnector 5 and are porous. However, the inorganic material that forms the fillet portions S ₁ and S ₂ is a gas passage. As long as the fillet portions S ₁ and S ₂ can be formed at the corners of 7a and 7b, they need not be conductive and need not be porous. For example, the fillet portion S can be formed of alumina or a solid electrolyte material.

(Conductive support 3a)
The conductive support 3a is a porous conductor and is gas permeable in order to allow the fuel gas to permeate to the fuel side electrode 3b. In addition, the conductive support 3a is required to be conductive in order to collect current via the interconnector layer 5. However, at the same time as satisfying such a requirement, inconvenience caused by simultaneous firing is avoided. Therefore, it is desirable that the support substrate 1 is composed of an iron group metal component and a specific rare earth oxide.

  The iron group metal component is for imparting conductivity to the support 3a, and may be a single iron group metal, or an iron group metal oxide, an iron group metal alloy or alloy oxide. May be. The iron group metals include iron, nickel, and cobalt. In the present invention, any of them can be used, but Ni and / or NiO is replaced with iron group because it is inexpensive and stable in fuel gas. It is preferable to contain as a metal component.

The rare earth oxide is used to approximate the thermal expansion coefficient of the support 3a to ZrO ₂ containing the rare earth element forming the solid electrolyte 3c, and maintains a high conductivity and is solid. In order to prevent diffusion into the electrolyte 3c and the like, an oxide containing at least one rare earth element selected from the group consisting of Y, Lu, Yb, Tm, Er, Ho, Dy, Gd, Sm, and Pr, Used in combination with the above iron group components. Specific examples of such rare earth oxides include Y ₂ O ₃ , Lu ₂ O ₃ , Yb ₂ O ₃ , Tm ₂ O ₃ , Er ₂ O ₃ , Ho ₂ O ₃ , Dy ₂ O ₃ , Gd ₂ O. ₃ , Sm ₂ O ₃ , Pr ₂ O ₃ can be exemplified, and Y ₂ O ₃ and Yb ₂ O ₃ are preferable in that they are particularly inexpensive.

(Interconnector 5)
Although the interconnector 5 is made of conductive ceramics, it is required to have reduction resistance and oxidation resistance because it is in contact with the fuel gas (hydrogen) and the oxygen-containing gas. For this reason, lanthanum chromite perovskite oxides (LaCrO ₃ oxides), titanium oxides, and the like are generally used as the conductive ceramics. Further, in order to prevent leakage of the fuel gas passing through the inside of the support 3a and the oxygen-containing gas passing through the outside of the support 3a, the conductive ceramics must be dense, for example, 93% or more, particularly 95%. It is preferable to have the above relative density.

(Fuel side electrode 3b)
The fuel side electrode 3b causes an electrode reaction, and is formed of a known porous conductive cermet. For example, it is formed from ZrO ₂ in which a rare earth element is dissolved, and Ni and / or NiO. As ZrO ₂ (stabilized zirconia) in which the rare earth element is dissolved, the same one used for forming the solid electrolyte 3c described below is preferably used.

  The stabilized zirconia content in the fuel side electrode 3b is preferably in the range of 35 to 65% by volume, and the Ni or NiO content is preferably 65 to 35% by volume. Further, the open porosity of the fuel side electrode 3b is preferably 15% or more, particularly in the range of 20 to 40%, and the thickness is improved between the performance and the solid electrolyte 3c and the fuel side electrode 3b. From the viewpoint of preventing peeling due to the difference in thermal expansion of the film, it is preferably 1 to 30 μm.

(Solid electrolyte 3c)
The solid electrolyte 3c provided on the fuel side electrode 3b is generally formed of a dense ceramic called ZrO ₂ (usually stabilized zirconia) in which 3 to 15 mol% of a rare earth element is solid-dissolved. Examples of rare earth elements include Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, but they are inexpensive. From the point, Y and Yb are desirable.

  The stabilized zirconia ceramic forming this solid electrolyte 3c is desirably a dense material having a relative density (according to Archimedes method) of 93% or more, particularly 95% or more from the viewpoint of preventing gas permeation. Is desirably 10 to 100 μm. The solid electrolyte 3c may be composed of a lanthanum gallate perovskite type composition in addition to the stabilized zirconia.

(Gas seal layer 31)
The gas seal layer 31 is preferably made of a solid electrolyte material film formed of a solid electrolyte material from the viewpoint of reducing the type of material used and ensuring gas sealing, but if it is a dense insulating material, For example, it may be formed of alumina.

  When the gas seal layers 31 formed on the side surfaces on both sides of the support substrate 1 are made of a solid electrolyte material film, the same material as the solid electrolyte 3c formed on the upper surface of the fuel side electrode 3b can be used. It is not necessary to use the same material as that of the solid electrolyte 3c, the composition may be slightly different, and a lanthanum gallate solid electrolyte material may be used. Further, since no power is generated in this portion, it is not necessary to use a solid electrolyte material, and as described above, insulating dense ceramics that are generally used may be used. As with the solid electrolyte 3c, the thickness of the gas seal layer 31 made of the solid electrolyte material film is preferably 10 μm or more from the viewpoint of preventing gas permeation.

(Oxygen side electrode 3d)
The oxygen side electrode 3d is formed of a conductive ceramic made of a so-called ABO ₃ type perovskite oxide. As such a perovskite oxide, at least one of transition metal perovskite oxides, particularly LaMnO ₃ oxides, LaFeO ₃ oxides, and LaCoO ₃ oxides having La at the A site is preferable. LaFeO ₃ -based oxides are particularly suitable because they have high electrical conductivity at an operating temperature of about 1000 ° C. In the perovskite oxide, Sr and the like may exist together with La at the A site, and Co and Mn may exist together with Fe at the B site.

  In addition, the oxygen side electrode 3d must have gas permeability. Therefore, the conductive ceramic (perovskite oxide) forming the oxygen side electrode 3d has an open porosity of 20% or more, particularly 30. It is desirable to be in the range of ˜50%. The thickness of the oxygen-side electrode 3d is desirably 30 to 100 μm from the viewpoint of current collection. Oxygen gas, air containing oxygen, or the like is supplied to the oxygen side electrode 3d.

  Hereinafter, a manufacturing method of the flat plate fuel cell stack will be described.

  First, for example, an organic binder, a solvent and the like are added to and mixed with a predetermined raw material powder, and this is tape-molded by a doctor blade method, and FIGS. 4 (a) to 4 (d) and FIGS. Seven types of tapes as shown in FIG.

  4A is an oxygen side electrode tape 33, FIG. 4B is a solid electrolyte tape 35, FIG. 4C is a fuel side electrode tape 37, FIG. 4D is a support tape 39, and FIGS. (C) is the interconnector tapes 41a, 41b and 41c.

The oxygen-side electrode tape 33, the fuel-side electrode tape 37, and the support tape 39 have through-holes formed in a frame shape in the tape thickness direction, and a gas seal layer 31 made of a solid electrolyte material film is formed in these through-holes. A solid electrolyte material 43 to be formed is filled. The interconnector tapes 41a and 41c for forming the gas passages 7a and 7b are formed with a plurality of through holes for forming the gas passages 7a and 7b, respectively. A gas passage forming material 45 formed by mixing an inorganic material forming S ₁ and S ₂ and a scattering substance scattered during firing is filled. As described above, the inorganic material forming the fillet portion S is preferably made of an interconnector material in terms of compatibility with the interconnector. In addition, it is desirable that the scattering material scattered during firing is a resin such as paraffin wax or carbon.

  Except for the solid electrolyte tape 35, each tape can be formed with a through hole having a rectangular cross section (thru hole) in the thickness direction by pressing, and the solid electrolyte material 43 and gas can be formed in the through hole by screen printing. A paste containing the passage forming material 45 can be filled. The solid electrolyte material 43 and the gas passage forming material 45 may be formed in a sheet shape and accommodated in the through hole.

  First, as shown in FIG. 6, an interconnector tape 41 b and an interconnector tape 41 a are laminated on the interconnector tape 41 c of FIG. 5C, and each through-hole is formed on the interconnector molded body. Two support tapes 39 of FIG. 4D are laminated so that the solid electrolyte material 43 is in the same position, and the solid electrolyte material 43 in each through hole is placed in the same position on the upper surface of the laminate. As shown, a fuel cell molded body can be produced by laminating the fuel side electrode tape 37 of FIG. 4C, the solid electrolyte tape 35 of FIG. 4B, and the oxygen side electrode tape 33 of FIG. 4A. . After repeating these laminations, a block in which a plurality of stacked molded bodies are formed can be produced by applying pressure. In FIG. 6, the number of stacked tapes is reduced to facilitate understanding.

  Thereafter, the central portion (frame shape) on which the solid electrolyte material 43 of each layer is laminated is cut at a position indicated by a one-dot chain line (FIGS. 4A and 6), that is, both end portions of the solid electrolyte material 43 are cut. In addition to cutting, it is cut at an intermediate position in the thickness direction of the solid electrolyte material 43, and three stacked molded bodies can be produced from one laminated molded body. By degreasing and firing the stack molded body, the scattered substances of the gas passage forming material 45 are scattered to form the gas passages 7a and 7b, and the fuel cell stack of the present invention can be manufactured.

  As shown in FIG. 3, the gas passages 7a and 7b of the fuel battery cell manufactured by such a sheet lamination method have irregularities on the inner surface depending on the state of the interconnector sheets 41a, 41b and 41c to be laminated. Therefore, it can be clearly determined whether or not it has been produced by a sheet lamination method. In FIG. 3, seven interconnector sheets 41a, four interconnector sheets 41b, and seven interconnector sheets 41c are laminated.

Then, in the process of the present invention, by firing the stack shaped body, together with the scattering material of the gas passage forming material 45 is scattered, so that the inorganic material is indicated by reference numeral S _1, S ₂ in FIG. 3, inter The fillet portions S ₁ and S ₂ can be formed by diffusing in the four corners of the gas passages 7 a and 7 b of the connector 5.

In other words, the laminated molded body of the fuel cell is pressurized to improve the adhesion of each tape. At this time, as shown in FIG. 3, the side surface of the space forming the gas passage is inwardly convex. The four corners become acute angles, and the interconnector sheets 41a, 41b, 41c at the four corners are peeled off, and cracks are likely to occur in the interconnector sheets 41a, 41c and the electrode sheet. However, since the space for forming the gas passages 7a and 7b is filled with the gas passage forming material 45 containing an inorganic material, by firing the laminated molded body, as shown in FIG. The inorganic material in the material 45 is diffused into the four corners of the gas passages 7a and 7b by capillary action, and the fillet portions S ₁ and S ₂ can be formed.

In such a fuel cell stack, fillet portions S ₁ and S ₂ are formed at the corners of the gas passages 7 a and 7 b of the interconnector 5. Therefore, when the fuel cell stack is manufactured, the corners of the gas passages 7 a and 7 b are formed. The generation of cracks and cracks in the gas passages 7a and 7b can be suppressed even when power generation is performed for a long time, and gas leakage from the gas passages 7a and 7b can be prevented.

That is, the corner by the wall section S _1, the peeling at the corners of the recess formed at the corners of the recess formed by the interconnector sheet 41a and the interconnector sheet 41b, the interconnector sheet 41b and the interconnector sheet 41c, cracks the generation suppression corner by meat section S _2, the corner portion formed by the interconnector sheet 41a and the fuel-side electrode tape 37, peeling at the corner formed by the interconnector sheet 41c and the oxygen-side electrode tape 33 The occurrence of cracks can be suppressed.

  In the above embodiment, the case where the cell stack is manufactured by simultaneous firing has been described. However, the present invention can also be applied to the case where a fuel cell in which a fuel cell and an interconnector are stacked is fired simultaneously. In this case, a cell stack is configured by stacking a plurality of fuel cells produced by simultaneous firing.

The present invention can also be applied to the case where only the interconnector is baked and manufactured. That is, in the above embodiment, the interconnector sheets 41a, 41b and 41c are stacked and fired simultaneously to produce an interconnector. In this case, the interconnector sheet 41a and the interconnector sheet 41b are formed. corners of the recess being formed meat portion S ₁ corner to corner in the recess formed by the interconnector sheet 41b and the interconnector sheet 41c is, cracking peeling at the recess at the time of manufacturing the interconnector, the occurrence of cracks Can be suppressed.

  Further, in the above embodiment, an example in which the recesses 5a and 5b are formed on both sides of one interconnector 41 has been described. However, two types of interconnectors are used, one interconnector is provided with a recess 5a, and the other interconnector is provided with The present invention can also be applied to a flat plate fuel cell provided with a recess 5b.

  Further, in the above embodiment, the fuel cell device has been described in which the gas seal layer 31 is provided and the gas discharged from the cell stack is recovered. However, in the present invention, the gas is supplied to the flat fuel without forming the gas seal layer 31. The present invention can be applied to a cell stack of a type that is ejected to the side of a battery cell and burned. In this case, since the cell stack tends to become hot, the present invention can be preferably used.

  Furthermore, in the above embodiment, the example in which the recesses 5a and 5b are formed on both sides of one interconnector 41 has been described. However, through holes are formed in each of the two interconnectors, and these two interconnectors are made of conductive and gas. It may be connected via a partition plate that does not pass through. In this case, a recess is formed by the through hole of the interconnector and the partition plate.

It is a perspective view which shows the flat fuel cell stack of this invention. It is sectional drawing which shows the flat fuel cell apparatus of this invention. It is an expanded sectional view of a gas passage part. It is a top view of the various tapes used for the manufacturing method of a fuel cell stack, (a) is a tape for oxygen side electrodes, (b) is a tape for solid electrolytes, (c) is a tape for fuel side electrodes, (d) is a support It is a body tape. It is a top view of the interconnector sheet | seat used for the manufacturing method of a fuel cell stack. It is sectional drawing which shows a stack molded object.

Explanation of symbols

5 ... interconnectors 5a, 5b ... recesses 7a, 7b ... gas passage 3b ... fuel side electrode 3c ... solid electrolyte 3d ... oxygen side electrode 31 ... gas seal layer S ₁ , S ₂ ... fillet part

Claims (7)

A plurality of unsintered tapes containing interconnector material powder having a recess for forming a gas passage and being fired, and a fillet portion formed at the corner of the recess A flat plate fuel cell interconnector. A method for manufacturing an interconnector of a flat plate fuel cell having a recess for forming a gas passage, wherein the green tape is formed by laminating a plurality of unsintered tapes having through holes in the thickness direction and containing interconnector material powder. And a gas passage formed of an inorganic material that forms a fillet portion at the corner of the recess and a disappearing substance that disappears during firing in a recess of the gas passage formed by the through holes of the plurality of unsintered tapes. A method for producing an interconnector for a flat plate fuel cell, wherein the interconnector molded body containing the forming material is formed through a firing step. A flat plate type fuel cell in which a flat plate type fuel cell having electrodes provided on both sides of a solid electrolyte is laminated with an interconnector that connects to one of the electrodes and forms a gas passage for supplying gas to the electrode. The solid electrolyte, the one electrode, and the interconnector are formed by simultaneous firing, and a fillet portion is formed at a corner of the gas passage. battery. 4. The flat plate fuel cell according to claim 3, wherein a fillet portion is formed at a corner portion of the gas passage formed by the one electrode and the interconnector. 5. The flat plate fuel cell according to claim 3, wherein the gas passage is formed by an electrode to which the interconnector is connected and a recess formed on the electrode side of the interconnector. A flat fuel cell having electrodes provided on both sides of a solid electrolyte and an interconnector connected to one of the electrodes and forming a gas passage for supplying gas to the electrode are alternately laminated. The flat plate fuel cell stack is formed by simultaneously firing the flat plate fuel cell and the interconnector, and a fillet portion is formed at a corner of the gas passage. A fuel cell molded body in which electrode molded bodies are provided on both sides of a solid electrolyte molded body and an interconnector molded body are alternately laminated, and formed on the one electrode molded body side of the interconnector molded body. A method for producing a flat plate fuel cell stack, characterized in that a stack molded body in which a gas passage forming material composed of an inorganic material and a scattering substance scattered during firing is accommodated in a recess is subjected to a firing step.

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