JP4683889B2 - FUEL CELL, PROCESS FOR PRODUCING THE SAME, AND FUEL CELL - Google Patents

Description

  The present invention relates to a fuel cell, a method for producing the same, and a fuel cell, and more particularly to a fuel cell for distributed power generation suitably used for homes and stores of less than 7 kW, a method for producing the same, and a fuel cell.

Recently, as a next-generation energy, fuel cells have been proposed for accommodating the cell Luz tuck storage container.

  FIG. 5 shows a fuel cell 1 of a conventional solid oxide fuel cell. The fuel cell 1 is flat air that also serves as a porous support having a plurality of gas flow paths 3 in the axial direction. A dense solid electrolyte 1b and an outer electrode 1c made of a porous fuel electrode are sequentially formed on the outer peripheral surface of the inner electrode 1a made of an electrode. The inner electrode 1a exposed from the solid electrolyte 1b and the outer electrode 1c is provided with an interconnector 1d so as not to be connected to the outer electrode 1c, and is electrically connected to the inner electrode 1a.

  In such a fuel cell 1, by making the shape flat, the area of the power generation unit per fuel cell 1 can be increased, and the amount of power generation can be increased.

  The fuel cell is configured by storing a plurality of the fuel cells 1 in a storage container. For example, an oxygen-containing gas is supplied to the inside of the inner electrode 1a through an oxygen gas injection pipe 5 and a fuel gas ( Hydrogen is supplied to generate electricity at about 1000 ° C.

A portion where the inner electrode 1a, the solid electrolyte 1b, and the outer electrode 1c of the fuel cell 1 overlap each other is a power generation unit, and the current generated in the power generation unit uses the inner electrode 1a as a current path and passes through an interconnector 1d. It is connected to another fuel cell 1.
JP-A 63-261678

  Since the inner electrode 1a of such a fuel battery cell 1 has a long shape, it is generally formed by extrusion molding or the like, and is manufactured through a drying process and a calcining process. The molded body of the inner electrode 1a tends to crack between the side surface of the inner electrode 1a and the gas flow path 3 and between the gas flow paths 3 in the drying process and the calcining process, and has sufficient reliability. There was a problem that could not be secured.

  That is, the molded body of the inner electrode 1a formed by extrusion molding contracts with evaporation of moisture in the drying process and decomposition of the organic binder component in the calcination process. When the distance between the gas flow paths 3 is short, there is a problem that cracks are likely to occur because the space between the gas flow paths 3 inside the molded body contracts earlier than the outer surface of the molded body contracts.

  In particular, if the diameter of the gas flow path 3 is increased to increase the gas supply amount, or the inner electrode 1a is decreased in thickness to shorten the current path, the inner electrode 1a is likely to be cracked. It was.

  Conventionally, since the above viewpoint has not been taken into consideration, the production yield of fuel cells has been low. Further, even in the manufactured fuel cell, the relationship between the distance between the gas flow paths and the distance from the gas flow path to the support substrate, and the distance from the gas flow path to the support substrate and the side surface of the support substrate from the gas flow path No consideration was given to the relationship with the distance to the distance, and therefore an optimal support substrate structure was not obtained.

  An object of this invention is to provide the fuel cell and fuel cell which have the optimal support substrate structure, and to provide the manufacturing method of a fuel cell with a high manufacturing yield.

  The inventors have described the relationship between the distance between the gas flow paths and the distance from the gas flow path to the main surface of the support substrate molded body, and the distance from the gas flow path to the main surface of the support substrate molded body and the gas flow path. When the relationship from the distance from the side surface of the support substrate molded body to the side surface of the support substrate satisfies a certain relationship, cracks between the side surface of the support substrate molded body and the gas flow path and between the gas flow paths occur during the manufacturing process. I found out that it can be prevented. Further, in the manufactured fuel cell, the gas in the gas flow path can be sufficiently supplied from the gas flow path to the solid electrolyte via the support substrate, and the occurrence of cracks is small even when the start and stop are repeated. The headline and the present invention were reached.

That is, the fuel battery cell of the present invention has a cross-sectional shape composed of arc-shaped portions provided at both ends in the width direction and a pair of flat portions connecting these arc-shaped portions, and a plurality of gas flows having a circular cross-section. A fuel cell having a porous support substrate formed so that a passage passes through in the axial length direction, and a solid electrolyte and an electrode are formed on the support substrate, and the support substrate from the gas flow path L2> L1 where L1 is the distance to the main surface of the substrate, L2 is the distance between the gas channels, and L3 is the distance from the gas channel located on the side surface of the support substrate to the side surface of the support substrate. , L3> L1 is satisfied.

In such a fuel cell, since the distance from the gas flow path to the main surface of the support substrate is thin, the distance to the solid electrolyte provided on the support substrate is shortened, and the gas in the gas flow path is sufficient for the solid electrolyte. In addition, since the distance between the gas flow paths is long, the current can flow in a straight line between the gas flow paths between the main surfaces of the support substrate, and the current path is shortened. Power generation characteristics can be improved. In addition, since the distance between the gas flow path and the side surface of the support substrate is long, the strength of that portion can be sufficiently obtained, and the occurrence of cracks can be suppressed even if the start and stop are repeated.

The fuel cell manufacturing method of the present invention has a cross-sectional shape composed of arc-shaped portions provided at both ends in the width direction and a pair of flat portions that connect these arc-shaped portions, and a plurality of gas flows having a circular cross-section. A method of manufacturing a fuel cell having a porous support substrate formed by penetrating a passage in an axial length direction, and forming a solid electrolyte and an electrode on the support substrate, wherein a cross-sectional shape is a width direction A support substrate molded body formed of an arc-shaped portion provided at both ends and a pair of flat portions that connect these arc-shaped portions, and a plurality of gas passages having a circular cross section are formed through the axial length direction. with including a step of forming the support substrate compact is, the distance L11 from the gas flow path to the main surface of the supporting substrate molded body, the distance between the gas flow path L12, the support substrate molded body The support substrate is formed from the gas flow channel located on the side of the substrate When the distance to the side surface of the body is L13 , L12> L11 and L13> L11 are satisfied.

In such a fuel cell manufacturing method, the distance from the gas flow path to the main surface of the support substrate molded body is L11, the distance between the gas flow paths is L12 , and the gas flow located on the side surface side of the support substrate molded body is When the distance from the path to the side surface of the support substrate molded body is L13 , the shrinkage due to the drying process or the like is caused by the drying process or the like on the outer surface (supported from the gas flow path) by setting L12> L11 and L13> L11. Since this occurs first from the main surface of the substrate, the tensile stress due to the contraction generated between the gas flow paths can be relaxed, and the occurrence of cracks can be suppressed. In addition, the stress generated by the shrinkage on the outer peripheral side surface (from the gas flow path to the side surface of the support substrate molded body) where the shrinkage proceeds most quickly can be alleviated by slowing the drying shrinkage. Cracks occurring between the side surfaces of the molded body can be suppressed.

  Moreover, as for the manufacturing method of the fuel battery cell of this invention, it is desirable that L11 is 0.5 mm or more. In such a fuel cell manufacturing method, it is possible to suppress the occurrence of cracking due to stress that occurs on the outer surface (from the gas flow path to the main surface of the support substrate molded body) as the support substrate molded body contracts.

  The fuel cell of the present invention is characterized in that a plurality of the above-described fuel cells are accommodated in a storage container. In such a fuel cell, the power generation characteristics of the fuel battery cell can be improved and damage can be prevented, so that a fuel cell with excellent reliability and power generation characteristics can be provided.

  In the fuel cell of the present invention, power generation characteristics can be improved, and deterioration and breakage can be reduced. Moreover, in the manufacturing method of the fuel cell of the present invention, damage during the manufacturing process can be prevented, and the manufacturing yield can be improved.

  As shown in FIG. 1, the fuel cell of the present invention has a plate-like cross section, a plate shape as a whole, and a columnar porous conductive support (hereinafter referred to as a support substrate) 33a. Therefore, a porous fuel side electrode 33b is provided so as to cover the flat main surface of the support substrate 33a and the arc-shaped side surfaces at both ends, and the fuel substrate electrode 33b is further densely covered. A solid electrolyte 33c is stacked, and an oxygen side electrode 33d is sequentially stacked on the solid electrolyte 33c. An intermediate film 33e, an interconnector 33f, and a P-type semiconductor 33g are sequentially stacked on the flat main surface of the other side of the support substrate 33a opposite to the oxygen side electrode 33d.

  The fuel cell of the present invention is plate-like and columnar as a whole, and six gas flow paths 34 having a circular cross section are provided in the axial length (length) direction on the support substrate 33a inside. Is formed.

  That is, the fuel cell 33 has a cross-sectional shape including an arc-shaped portion B provided at both ends in the width direction and a pair of flat portions A that connect these arc-shaped portions B. It is flat and formed substantially in parallel. One of the flat portions A of these fuel cells 33 is configured by forming a fuel side electrode 33b, a solid electrolyte 33c, and an oxygen side electrode 33d on one main surface of the support substrate 33a, and the other flat portion A. Is configured by forming an intermediate film 33e, an interconnector 33f, and a P-type semiconductor 33g on the other main surface of the support substrate 33a.

  The solid electrolyte 33c extends from one main surface of the support substrate 33a to the other main surface via the side surfaces on both sides, and overlaps the interconnector 33f.

  The portion where the fuel side electrode 33b, the solid electrolyte 33c, and the oxygen side electrode 33d overlap is the power generation unit. This power generation portion may be formed up to the arcuate portion B. In the fuel cell 33, the power generation part formed in the flat part A is the main power generation part.

  In addition, it is desirable that the arc-shaped portion B has a curved surface in order to relieve the thermal stress generated due to heating and cooling accompanying power generation.

  In addition, it is desirable that the major dimension of the support substrate 33a (the distance between the side surfaces of the support substrate that forms the arc-shaped portion) is 15 to 40 mm, and the minor diameter dimension (the distance between the main surfaces that forms the flat portion) is 2 to 10 mm. In addition, although the shape of the support substrate 33a is expressed as a plate shape, it can also be expressed as an elliptical shape or a flat shape by changing the major axis dimension and the minor axis dimension.

  As the thickness of the support substrate 33a is reduced, cracks are more likely to occur. Therefore, it is effective to use the present invention when the distance between the main surfaces of the support substrate 33a is 8 mm or less, further 5 mm or less.

  Further, as shown in FIG. 2, six gas passages 34 are formed in the support substrate 33a so as to penetrate in the axial direction, and the distance L2 between the gas passages 34 at the open end is determined by shrinkage in drying. Is caused to occur from the outer surface and is set to 1 to 3 mm from the viewpoint of preventing cracks generated between the gas flow paths. Further, the distance L3 between the gas flow path 34 closest to the side surface of the support substrate 33a and the side surface of the support substrate 33a is 1 to 3 mm from the viewpoint of relaxing the speed at which drying shrinkage occurs and preventing cracks occurring on the side surface portion. It is said that. Furthermore, the distance L1 between the gas flow path 34 and the main surface of the support substrate 33a is set to 0.5 to 1 mm from the viewpoint of relieving stress due to drying shrinkage generated on the outer surface.

In the fuel cell of the present invention, the distance from the gas flow path 34 to the main surface of the support substrate 33a is L1, the distance between the gas flow path 34 and the adjacent gas flow path 34 is L2 , and the gas flow path 34. When the distance from the side surface of the support substrate 33a to L3 is L3 , the relationship of L2> L1 and L3> L1 is satisfied. By satisfying such a relational expression, since the distance L2 between the gas flow paths 34 of the thin support substrate 33a is large, a current can flow in a straight line therebetween, and the distance between the interconnector 33f and the oxygen-side electrode 33d. The current path can be shortened. Further, since the distance L1 from the gas flow path 34 to the main surface of the support substrate 33a is shorter than the distance L2 between the gas flow paths 34, the fuel gas flowing through the gas flow path 34 is mutually exchanged between the gas flow paths 34. It is easier to flow to the main surface of the support substrate 33a than to circulate and can be sufficiently supplied to the solid electrolyte 33c via the support substrate 33a and the fuel electrode 33b.

Furthermore , since the distance L3 from the gas flow path 34 to the side surface of the support substrate 33a is longer than the distance L1 between the gas flow path 34 and the main surface of the support substrate 33a, even if the start and stop of the fuel cell are repeated, the side surface portion Can prevent cracks. Furthermore, in such a fuel cell, even when power generation is performed at a high fuel utilization rate, the support substrate near the gas flow path outlet does not deteriorate or break.

  The distance L1 from the gas flow path 34 to the main surface of the support substrate 33a is parallel to the main surface of the support substrate 33a, and the distance between the straight line in contact with the gas flow path 34 and the main surface of the support substrate 33a is measured. Can be obtained. Further, the distance L2 between the gas flow paths 34 is obtained by measuring the distance between parallel straight lines (perpendicular to the main surface) in contact with each. Further, the distance L3 from the gas flow path 34 to the side surface of the support substrate 33a is a distance between the gas flow path 34 located on the outermost side and a parallel straight line (perpendicular to the main surface) contacting the side surface of the support substrate 33a. Can be obtained.

  This support substrate 33a is composed mainly of a rare earth element oxide composed of one or more selected from Y, Lu, Yb, Tm, Er, Ho, Dy, Gd, Sm and Pr, and Ni and / or NiO. It is desirable to do.

The intermediate film 33e formed between the support substrate 33a and the interconnector 33f is composed mainly of ZrO ₂ containing Ni and / or NiO and a rare earth element. The Ni conversion amount of the Ni compound in the intermediate film 33e is preferably 35 to 80% by volume, more preferably 50 to 70% by volume, based on the total amount. By setting Ni to 35% by volume or more, the conductive path by Ni is increased, the conductivity of the intermediate film 33e is improved, and the voltage drop is reduced. Moreover, by making Ni 80 volume% or less, the thermal expansion coefficient difference between the support substrate 33a and the interconnector 33f can be made small, and generation | occurrence | production of the crack of both interface can be suppressed.

  In addition, the thickness of the intermediate film 33e is preferably 20 μm or less, and more preferably 10 μm or less from the viewpoint that the potential drop is reduced.

The thermal expansion coefficient of the medium rare earth element or heavy rare earth element oxide is smaller than the thermal expansion coefficient of ZrO ₂ containing Y ₂ O ₃ of the solid electrolyte 33c, and the thermal expansion coefficient of the support substrate 33a as a cermet material with Ni. Can be brought close to the thermal expansion coefficient of the solid electrolyte 33c, and cracking of the solid electrolyte 33c and separation of the solid electrolyte 33c from the fuel side electrode 33b can be suppressed. By using a heavy rare earth element oxide having a small thermal expansion coefficient, the amount of Ni in the support substrate 33a can be increased, and the heavy rare earth element oxide is also used from the viewpoint that the electrical conductivity of the conductive support 33a can be increased. It is desirable.

  The light rare earth elements La, Ce, Pr, and Nd oxides may be medium rare earth elements, heavy rare earth elements as long as the sum of the thermal expansion coefficients of the rare earth element oxides is less than the thermal expansion coefficient of the solid electrolyte 33c. There is no problem even if it is contained in addition to the elements.

  Moreover, the raw material cost can be significantly reduced by using a complex rare earth element oxide containing a plurality of inexpensive rare earth elements in the course of purification. Also in that case, it is desirable that the thermal expansion coefficient of the complex rare earth element oxide is less than the thermal expansion coefficient of the solid electrolyte 33c.

  Further, it is desirable to provide a P-type semiconductor 33g made of, for example, a transition metal perovskite oxide on the surface of the interconnector 33f. When a metal current collecting member is disposed directly on the surface of the interconnector 33f to collect current, the potential drop increases due to non-ohmic contact. In order to make ohmic contact and reduce the potential drop, it is necessary to connect the P-type semiconductor 33g to the interconnector 33f, and it is desirable to use a transition metal perovskite oxide that is a P-type semiconductor. The transition metal perovskite oxide is preferably made of at least one of a lanthanum-manganese oxide, a lanthanum-iron oxide, a lanthanum-cobalt oxide, or a composite oxide thereof.

The fuel side electrode 33b provided on the main surface of the support substrate 33a is composed of Ni and ZrO _{2 in} which a rare earth element is dissolved. The thickness of the fuel side electrode 33b is desirably 1 to 30 μm. By setting the thickness of the fuel side electrode 33b to 1 μm or more, a three-layer interface as the fuel side electrode 33b is sufficiently formed. Further, by setting the thickness of the fuel side electrode 33b to 30 μm or less, it is possible to prevent interface peeling due to a difference in thermal expansion from the solid electrolyte 33c.

The solid electrolyte 33c provided on the main surface of the fuel side electrode 33b is made of a dense ceramic made of partially stabilized or stabilized ZrO ₂ containing 3 to 15 mol% of a rare earth element such as Y. As the rare earth element, Y or Yb is desirable because it is inexpensive.

  The thickness of the solid electrolyte 33c is desirably 10 to 100 μm. Gas permeation can be prevented by setting the thickness of the solid electrolyte 33c to 10 μm or more. Moreover, the increase in a resistance component can be suppressed by making the thickness of the solid electrolyte 33c into 100 micrometers or less.

The oxygen side electrode 33d is made of a lanthanum-manganese oxide, lanthanum-iron oxide, lanthanum-cobalt oxide of a transition metal perovskite oxide, or at least one porous oxide of a composite oxide thereof. It is composed of conductive ceramics. The oxygen side electrode 33d is preferably a (La, Sr) (Fe, Co) O ₃ system in terms of high electrical conductivity in the middle temperature range of about 800 ° C. The thickness of the oxygen-side electrode 33d is desirably 30 to 100 μm from the viewpoint of current collection.

  The interconnector 33f is a dense body for preventing leakage of fuel gas and oxygen-containing gas inside and outside the support substrate 33a, and the inner and outer surfaces of the interconnector 33f are in contact with the fuel gas and oxygen-containing gas. It has reduction resistance and oxidation resistance.

  The thickness of the interconnector 33f is desirably 30 to 200 μm. By setting the thickness of the interconnector 33f to 30 μm or more, gas permeation can be completely prevented, and by setting it to 200 μm or less, an increase in resistance component can be suppressed.

Between the end of the interconnector 33f and the end of the solid electrolyte 33c, for example, a bonding layer made of Ni and ZrO _{2 in} which Y ₂ O ₃ is dissolved is interposed in order to improve the sealing performance. Also good.

  The support substrate 33a and the inner electrode 33b described above can be replaced with a conventionally used inner electrode that also serves as a support. That is, you may form the support substrate 33a and the inner side electrode 33b from the fuel side electrode etc. which consist of Ni and YSZ, for example.

  The manufacturing method of the fuel cell 33 as described above will be described. First, a rare earth element oxide powder excluding La, Ce, Pr, and Nd elements and Ni and / or NiO powder are mixed, and a support substrate material in which an organic binder and a solvent are mixed is extruded into the mixed powder. Then, a plate-like support substrate molded body 55 as shown in FIG. 3 is produced, and this is dried and degreased.

  The support substrate molded body 55 has a major axis dimension (a distance between the side surfaces of the support substrate molded body 55 forming the arc-shaped portion) of 15 to 40 mm, and a minor axis dimension (a distance between main surfaces forming the flat portion) of 2.5 to 12. .5mm is desirable. As the thickness of the support substrate molded body 55 becomes thinner, cracks are more likely to occur. Therefore, the present invention is effective when the distance between the main surfaces of the support substrate molded body 55 is 10 mm or less, more preferably 6.3 mm or less. Is.

  Further, six gas flow paths 34 are formed in the axial direction in the support substrate molded body 55, and the distance L12 between the gas flow paths 34 at the opening ends is set to 1.2 to 3.8 mm. The distance L13 between the flow path 34 and the side surface of the support substrate molded body 55 is 1.2 to 3.8 mm, and the distance L11 between the gas flow path 34 and the main surface of the support substrate molded body 55 is 0.6 to It is set to 1.3 mm.

In the support substrate molded body 55, the distance from the gas flow path 34 to the main surface of the support substrate molded body 55 is L11, the distance between the gas flow path 34 and the gas flow path 34 is L12 , and the gas flow path 34 to the support substrate. When the distance to the side surface of the molded body 55 is L13 , the relationship of L12> L11 and L13> L11 is satisfied. By satisfying such a relationship, the shrinkage due to drying or the like occurs earlier from the outer surface than between the gas flow paths, so the tensile stress due to the shrinkage generated between the gas flow paths can be relieved, and in the drying process It is possible to suppress the frequent cracks between the gas flow paths. In addition, the stress generated by the shrinkage on the outer peripheral side surface where shrinkage due to drying etc. proceeds the fastest can be alleviated by slowing the drying shrinkage, and between the gas flow path and the side surface frequently generated in the drying process. Can be prevented from cracking.

  Here, L11 is desirably 0.6 mm or more. Thereby, the crack which generate | occur | produces in the outer surface with the shrinkage | contraction of the support substrate molded object 55 can be suppressed.

  Moreover, after drying at room temperature for 3 days, it is desirable to dry for 2 hours or more in a temperature range of 80 ° C. to 150 ° C. Furthermore, after drying, calcination is performed in a temperature range of 800 to 1100 ° C.

Next, Ni and / or NiO powder, ZrO ₂ powder in which a rare earth element is dissolved, an organic binder, and a solvent are mixed to produce a slurry that becomes a fuel-side electrode molded body.

  Next, the slurry used as a fuel side electrode is apply | coated to the thickness of 2-10 micrometers using the mesh platemaking on the one side main surface of the said support substrate molded object, and it dries at the temperature of 80-150 degreeC.

Next, a sheet-like solid electrolyte molded body is prepared using a solid electrolyte material in which a rare earth element is solid-solved ZrO ₂ powder, an organic binder, and a solvent. Next, a slurry to be the fuel side electrode is applied to one side of the solid electrolyte molded body so as to have a thickness of 5 to 15 μm after firing, and the fuel formed on the one side main surface of the support substrate molded body The coating film serving as the fuel-side electrode of the solid electrolyte molded body is in contact with the coating film serving as the side electrode, and both end surfaces of the solid electrolyte molded body are spaced apart from each other at a predetermined interval on the other main surface. Wrap around and dry at a temperature of 80-150 ° C.

  Next, a sheet-like interconnector molded body is prepared using an interconnector material in which a lanthanum-chromium oxide powder, an organic binder, and a solvent are mixed.

Next, a slurry to be an intermediate film molded body in which Ni and / or NiO powder, ZrO ₂ powder in which a rare earth element is solid-solved, an organic binder, and a solvent is mixed is prepared and applied to one surface of the interconnector molded body. .

  Next, the sheet-like interconnector molded body is laminated so that the surface on which the slurry is applied comes into contact with the exposed support substrate molded body.

  Thereby, while laminating the fuel side electrode molded body and the solid electrolyte molded body sequentially on the one side main surface of the support substrate molded body, the intermediate film molded body and the interconnector molded body are laminated on the other side main surface. Create a body. In addition, each molded object can be produced by sheet | seat shaping | molding by a doctor blade, printing, slurry dip, spraying by spraying, etc., or may be produced by a combination thereof.

  Next, the multilayer molded body is degreased and cofired at 1300 to 1600 ° C. in an oxygen-containing atmosphere.

  Next, a transition metal perovskite oxide powder, which is a P-type semiconductor, and a solvent are mixed to prepare a paste, and the laminate is dipped in the paste, and is respectively placed on the surfaces of the solid electrolyte 33b and the interconnector 33f. The fuel cell 33 of the present invention can be produced by forming the oxygen-side electrode molded body and the P-type semiconductor molded body by dipping, or by direct spray coating and baking at 1000 to 1300 ° C.

  In addition, since the Ni component in the support substrate 33a, the fuel-side electrode 33b, and the intermediate film 33e is NiO by firing in the oxygen-containing atmosphere, the fuel battery cell 33 is subsequently reduced from the support substrate 33a side. Then, NiO is reduced at 800 to 1000 ° C. Further, this reduction process may be performed during power generation.

  As shown in FIG. 4, the cell stack is formed by assembling a plurality of fuel cells 33, and a metal felt and / or a metal plate is interposed between one fuel cell 33 and the other fuel cell 33. The supporting substrate 33a of one fuel cell 33 is interposed between the intermediate film 33e, the interconnector 33f, the P-type semiconductor 33g, and the collecting member 43 provided on the supporting substrate 33a. The fuel cell 33 is electrically connected to the oxygen side electrode 33d.

  The current collecting member 43 is preferably made of at least one of Pt, Ag, Ni-base alloy, and Fe—Cr steel alloy from the viewpoint of heat resistance, oxidation resistance, and electrical conductivity. Reference numeral 42 denotes a conductive member for connecting the fuel cells in series.

  The fuel cell of the present invention is configured by storing the cell stack of FIG. 4 in a storage container. This storage container is provided with an introduction pipe for introducing a fuel gas such as hydrogen and an oxygen-containing gas such as air into the fuel cell 33 from the outside, and the fuel cell 33 is heated to a predetermined temperature to generate power. The used fuel gas and oxygen-containing gas are mixed and burned, and discharged out of the storage container.

  In addition, this invention is not limited to the said form, A various change is possible in the range which does not change the summary of invention. For example, the inner electrode may be formed from an oxygen side electrode. Further, a reaction preventing layer may be formed between the oxygen side electrode 33d and the solid electrolyte 33c.

Further, the support substrate 33a and the inner electrode 33b may be formed with the same composition. For example, ZrO _{2 in} which Ni and Y ₂ O ₃ are dissolved may be used. In this case, the support substrate 33a and the inner electrode 33b are replaced with an inner electrode that also serves as a support.

First, NiO powder is mixed to 48 volume% in terms of Ni metal, and Y ₂ O ₃ powder is mixed to 52 volume%, and this mixture is mixed with a pore agent, an organic binder composed of a cellulose-based binder, and a solvent composed of water. And the mixed support substrate material was extrusion molded to produce 30 plate-shaped support substrate molded bodies as shown in FIG. 3 under each condition.

  In the extrusion molding, the positional relationship of the gas flow paths of the support substrate molded body was changed so that L11, L12, and L13 had the dimensions shown in Table 1.

  The number of gas flow paths is 6, the shape is circular in cross section, the diameter is changed, and the thickness of the support substrate molded body and the distance between the side surfaces of the support substrate molded body are changed, so that L11, L12, L13 was changed.

  These support substrate molded bodies were dried at room temperature and then dried at 130 ° C. Then, the crack between gas flow paths and the crack in the side surface of a support substrate molded object were observed visually, and the ratio was described in Table 1. Thereafter, the support substrate molded body was processed so as to have a length of 200 mm after firing, and calcined at 1000 ° C.

Next, an acrylic binder and toluene are added to 8YSZ powder (ZrO ₂ containing 8 mol of Y ₂ O ₃ ) to produce a slurry that becomes a solid electrolyte molded body, and a sheet-shaped solid electrolyte molded body is obtained by a doctor blade method. Was made.

Next, 48% by volume of NiO powder in terms of metallic Ni and 8YSZ powder (ZrO ₂ containing 8 mol of Y ₂ O ₃ ) are mixed to 52% by volume, an acrylic binder and toluene are added, and fuel is added. The slurry used as the side electrode molded object was produced.

  The slurry to be the fuel-side electrode molded body was applied to the surface of one side main surface of the support substrate molded body using a mesh plate making and dried at a temperature of 130 ° C.

  Moreover, the slurry used as the said fuel side electrode molded object was screen-printed on the said solid electrolyte molded object, and it dried at the temperature of 130 degreeC.

  Next, the coating film to be the fuel-side electrode of the solid electrolyte molded body comes into contact with the coating film of the fuel-side electrode molded body formed on the support substrate molded body, and a gap between both ends of the coating film on the other side main surface is a predetermined interval. Then, it was wound so as to be separated and dried.

  Next, a sheet-like interconnector molded body was prepared using an interconnector material in which a lanthanum-chromium oxide powder, an organic binder, and a solvent were mixed.

Next, a slurry to be an intermediate film molded body in which Ni and / or NiO powder, ZrO ₂ powder in which a rare earth element is solid-solved, an organic binder, and a solvent was mixed was prepared and applied to one surface of the interconnector molded body. .

  Next, the sheet-like interconnector molded body is laminated so that the surface on which the slurry is applied is in contact with the exposed support substrate molded body, and this laminated body is debindered and co-fired at 1500 ° C. in the atmosphere. did.

Next, an oxygen-side electrode slurry is prepared from La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ powder and a solvent composed of normal paraffin, and this slurry is sprayed on the solid electrolyte, An electrode molded body is formed, and the slurry is applied to the outer surface of the fired interconnector 33f and baked at 1150 ° C. to form a P-type semiconductor 33g. The fuel cell 33 of the present invention as shown in FIG. Produced.

  The thickness of the solid electrolyte 33c formed between the fuel side electrode 33b and the oxygen side electrode 33d is 40 μm, the thickness of the oxygen side electrode 33d is 50 μm, the thickness of the fuel side electrode 33b is 10 μm, the thickness of the interconnector 33f is 50 μm, P The thickness of the mold semiconductor 33g was 50 μm. Further, 15 mm non-power generation portions were formed at both ends of each fuel cell 33.

  Next, hydrogen gas was allowed to flow inside the fuel battery cell 33, and reduction treatment of the support substrate 33a and the fuel side electrode 33b was performed at 850 ° C. In the obtained fuel cell, the thickness of the support substrate, the distance L1 from the gas flow path to the main surface of the support substrate, the distance L2 between the gas flow paths, the distance L3 from the gas flow path to the side surface of the support substrate, It described in Table 1.

With respect to the non-defective product of the obtained fuel battery cell 33, hydrogen was passed through the gas flow path 34, air was passed outside the fuel battery cell 33, and the fuel battery cell 33 was heated to 850 ° C. using a gas burner. After power generation for a period of time, the system was stopped and this start / stop operation was repeated 10 times, and cracks between the side surface of the support substrate and the gas flow path were confirmed.

  From Table 1, the support substrates are L2 <L1, L12 <L11, and sample Nos. Out of the scope of the present invention. In No. 4, 13 defects out of 30 samples were confirmed due to cracks between the gas flow path 34 and the gas flow path 34 after the completion of the drying process, and it was found that the yield was low.

  Further, the support substrates are L3 <L1, L13 <L11, and sample Nos. Out of the scope of the present invention. In No. 5, 14 defects out of 30 samples were confirmed due to cracks between the side surface and the gas flow path 34 after the completion of the drying process, and it was found that the yield was low.

In contrast, the sample No. 1 of the present invention in which the support substrate is L2> L1, L3> L1 . 1-3 , 6-9 , there are no cracks between the gas flow paths, no cracks between the side faces and the gas flow paths, and the production yield is high. There were no cracks.

It is a cross-sectional perspective view which shows the fuel battery cell of this invention. It is a cross-sectional view which shows the support substrate of this invention. It is a cross-sectional view which shows a support substrate molded object. It is sectional drawing which shows a cell stack. It is a cross-sectional view showing a conventional fuel cell.

Explanation of symbols

33 ... Fuel cell 33a ... Support substrate 33b ... Inner electrode (fuel side electrode)
33c: Solid electrolyte 33d: Outer electrode (oxygen side electrode)
34: Gas flow path L1: Distance from gas flow path to main surface of support substrate L2: Distance between gas flow paths L3: Distance from gas flow path to side surface of support substrate

Claims (4)

The cross-sectional shape is composed of arc-shaped portions provided at both ends in the width direction and a pair of flat portions that connect these arc-shaped portions, and a plurality of circular gas passages are formed penetrating in the axial length direction. A fuel cell having a porous support substrate and a solid electrolyte and an electrode formed on the support substrate, wherein the distance from the gas flow path to the main surface of the support substrate is L1, L2> L1 and L3> L1 are satisfied, where L2 is a distance between gas flow paths and L3 is a distance from the gas flow path located on the side surface side of the support substrate to the side surface of the support substrate. Fuel cell. The cross-sectional shape is composed of arc-shaped portions provided at both ends in the width direction and a pair of flat portions that connect these arc-shaped portions, and a plurality of circular gas passages are formed penetrating in the axial length direction. A fuel cell having a porous support substrate and a solid electrolyte and an electrode formed on the support substrate, wherein the cross-sectional shape is an arc-shaped portion provided at both ends in the width direction, and these arcuate portions are composed of a pair of flat portions for connecting, as well as comprising a step of forming a supporting substrate molded body in which a plurality of gas passages of circular cross section formed therethrough in the axial direction, the The gas flow path in which the support substrate molded body is located on the side surface side of the support substrate molded body, L11 is the distance from the gas flow path to the main surface of the support substrate molded body, L12 is the distance between the gas flow paths. And the distance from the side surface of the support substrate molding to L13 A fuel cell manufacturing method characterized by satisfying L12> L11 and L13> L11 . L11 is 0.5 mm or more, The manufacturing method of the fuel cell of Claim 2 characterized by the above-mentioned. A fuel cell comprising a plurality of the fuel cells according to claim 1 stored in a storage container.

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