JP4028813B2 - Fuel cell and fuel cell - Google Patents

Description

【００８９】
表１に示すように、燃料電池セル３３のＲ２／Ｒ１＝１であり、本発明の範囲外の試料Ｎｏ．１では、４０本の試料のうち、同時焼成時に８本、最終焼成時に４本、還元時に４本、発電試験時に２本の割れによる不良がでた。最終的には、４０本のうち、１８本の燃料電池セル３３の最薄肉部Ｂに割れや、クラックが確認され、歩留まりが低く、また、燃料電池セル３３の信頼性も低いことが判る。
【００９０】
一方、Ｒ２／Ｒ１が１．０３である本発明の試料Ｎｏ．２では、同時焼成時、最終焼成時、還元時、発電試験時を通して発生した割れは、６本であり、不良の発生を半減させることができた。また、発電試験時の割れの発生は、確認できず、信頼性が大幅に向上した。
【００９１】
また、Ｒ２／Ｒ１が１．１０である本発明の試料Ｎｏ．３では、同時焼成時、最終焼成時、還元時、発電試験時を通して発生した割れは、３本であり、不良の発生を大幅に減少でき、また、発電試験時の割れもなく、信頼性が大幅に向上した。
【００９２】
また、さらにＲ２／Ｒ１が１．２６以上である本発明の試料Ｎｏ．３〜７では、同時焼成時、最終焼成時、還元時、発電試験時を通して発生した割れは、いずれも０本であり、不良の発生を抑制でき、また、信頼性を大幅に向上できた。
【００９３】
【発明の効果】
本発明によれば、歩留まりが高く、信頼性に優れた燃料電池セル、燃料電池及びその製造方法を提供できる。
【図面の簡単な説明】
【図１】本発明の燃料電池セルを示す断面斜視図である。
【図２】本発明の導電性支持体の乾燥方法を示す横断面図である。
【図３】本発明のセルスタックを示す横断面図である。
【図４】従来の燃料電池セルを示す横断面図である。
【符号の説明】
３３・・・燃料電池セル
３３ａ・・・導電性支持体
３３ｂ・・・内側電極、燃料側電極
３３ｃ・・・固体電解質
３３ｄ・・・外側電極、酸素側電極
３４・・・ガス流路
Ｒ１・・・導電性支持体の厚み方向におけるガス流路の径
Ｒ２・・・導電性支持体の厚みと直交する方向におけるガス流路の径[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel cell and a fuel cell, and more particularly to a gas flow path shape formed in a conductive support.
[0002]
[Prior art]
In recent years, various fuel cells in which a stack of fuel cells is stored in a storage container have been proposed as next-generation energy.
[0003]
FIG. 4 shows a fuel cell 1 of a conventional solid oxide fuel cell. The fuel cell 1 has a flat inner side that also serves as a porous support having a plurality of gas flow paths 3 in the axial direction. On the outer peripheral surface on the electrode 1a, a dense solid electrolyte 1b and an outer electrode 1c made of porous conductive ceramics are sequentially formed. 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.
[0004]
In such a fuel cell 1, by making the shape of the fuel cell 1 flat, the area of the power generation unit per fuel cell 1 can be increased, and the amount of power generation can be increased.
[0005]
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 into the inner electrode 1a through an oxygen gas injection pipe 5, and a fuel gas (hydrogen) is supplied to the outer electrode 1c. To generate electricity at about 1000 ° C.
[0006]
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 (see Patent Document 1).
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 63-261678
[Problems to be solved by the invention]
In such a fuel cell 1, since the current path is shortened when the thickness of the fuel cell 1 is reduced, the amount of power generation per fuel cell 1 can be increased, but the thickness of the fuel cell 1 is reduced. As shown, the thinnest portion B of the flat portion of the fuel cell 1 tends to crack, and there is a problem that sufficient reliability cannot be ensured.
[0009]
That is, in the fuel battery cell 1 of FIG. 4, the gas flow path 3 having a circular cross section is formed in the inner electrode 1a, and the curvature of the gas flow path 3 in the thinnest portion is large. Since the thickness between the outer surfaces of the battery cell 1 (thinnest wall portion) is thinner and structurally weaker than the portion where the gas flow path 3 is not formed, the fuel cell 1 is fired, reduced, and There was a problem that cracks were likely to occur due to the stress generated during power generation.
[0010]
An object of the present invention is to provide a fuel cell and a fuel cell with high yield and excellent reliability.
[0011]
[Means for Solving the Problems]
The fuel battery cell of the present invention forms a power generation unit by sequentially providing a fuel side electrode, a solid electrolyte, and an oxygen side electrode on one main surface of a plate-like conductive support having a plurality of gas flow paths. together comprising Te, a fuel cell formed by providing the interconnector on the other side main surface, wherein the gas flow path in the elliptical shape, the diameter of the gas flow path in the thickness direction of the plate-shaped conductive support R1, R2> R1 is satisfied, where R2 is the diameter of the gas flow path in the direction orthogonal to the thickness of the plate-like conductive support.
[0012]
In such a fuel battery cell, by setting the diameter of the gas flow path to R2> R1, a portion where the thickness between the gas flow path and the outer surface of the fuel battery cell becomes thin (the thinnest part) is formed. The gas flow path in the thinnest part has a hole shape with a small curvature with respect to the flat part of the fuel cell, so the stress generated in the thinnest part of the fuel cell is reduced during firing, reduction treatment, and power generation It is possible to suppress the occurrence of cracks in the thinnest part of the fuel cell.
[0013]
The fuel battery cell according to the present invention includes a solid electrolyte and an oxygen side electrode sequentially provided on one side main surface of a fuel side electrode that also serves as a plate-like support in which a plurality of gas flow paths are formed. together comprising, a fuel cell formed by providing the interconnector on the other side main surface, wherein the gas flow path in the elliptical shape, the gas flow path in the thickness direction of the fuel-side electrode serves as the plate-like support R2> R1 is satisfied, where R1 is the diameter and R2 is the diameter of the gas flow path in the direction orthogonal to the thickness of the fuel side electrode serving also as the plate-like support.
[0014]
In such a fuel battery cell, by setting the diameter of the gas flow path to R2> R1, stress generated in the thinnest part of the fuel battery cell during firing can be relieved, and the thinnest part of the fuel battery cell Generation of cracks can be suppressed.
[0015]
Further, the fuel cell of the present invention is characterized in that R2 is 1.03 times or more of R1. In such a fuel cell, the stress generated in the thinnest portion of the fuel cell can be effectively relieved, and the occurrence of cracks in the thinnest portion of the fuel cell can be suppressed.
[0018]
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, damage to the fuel cell can be prevented, so that a fuel cell and a fuel cell with excellent reliability can be provided.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 1, the fuel battery cell of the present invention has a plate-like cross-section and a column-shaped porous conductive support 33a as a whole, and one of the conductive supports 33a. A porous fuel-side electrode 33b, a dense solid electrolyte 33c, and an oxygen-side electrode 33d made of porous conductive ceramics are sequentially laminated on the side flat surface and the arcuate surfaces at both ends. An intermediate film 33e, an interconnector 33f made of a lanthanum-chromium oxide material, and a current collecting film 33g made of a P-type semiconductor material are formed on the flat surface of the conductive support 33a opposite to the oxygen side electrode 33d. ing.
[0020]
Further, the fuel cell of the present invention is a columnar shape on the whole, a plurality of oval-shaped gas channel 34 is formed in the axial direction inside thereof.
[0021]
That is, the fuel cell 33 has a cross-sectional shape including arc-shaped portions m provided at both ends in the width direction, and a pair of flat portions a that connect these arc-shaped portions m. The pair of flat portions a It is flat and formed substantially in parallel. One of the flat portions a of these fuel cells 33 is configured by forming an intermediate film 33e, an interconnector 33f, and a current collecting film 33g on the other main surface of the conductive support 33a, and the other flat portion. a is formed by forming a fuel side electrode 33b, a solid electrolyte 33c, and an oxygen side electrode 33d on one main surface of the conductive support 33a.
[0022]
The solid electrolyte 33c extends from the one side main surface of the conductive support 33a to the other side main surface so as to form the arc-shaped portions m on both sides, and overlaps the interconnector 33e.
[0023]
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 arc-shaped portion m. In the fuel cell 33, the power generation unit formed on the flat portion a is the main power generation unit.
[0024]
In addition, it is desirable that the arc-shaped portion m has a curved surface in order to relieve the thermal stress generated by heating and cooling accompanying power generation.
[0025]
Further, it is desirable that the conductive support 33a has a major axis dimension (distance in the arc-shaped part mm direction) of 15 to 35 mm and a minor axis dimension (distance in the flat part a-a direction) of 2 to 4 mm. In addition, although the shape of the electroconductive support 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.
[0026]
The conductive support 33a is composed of one or more rare earth element oxides selected from Y, Lu, Yb, Tm, Er, Ho, Dy, Gd, Sm, and Pr, and Ni and / or NiO. It is desirable to use as a main component.
[0027]
The intermediate film 33e formed between the conductive support 33a and the interconnector 33f is mainly composed of Ni and / or ZrO ₂ containing 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 electroconductive support body 33a and the interconnector 33f can be made small, and generation | occurrence | production of the crack of both interface can be suppressed.
[0028]
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.
[0029]
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 heat of the conductive support 33a as a cermet material with Ni. The expansion coefficient 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 conductive support 33a can be increased, and the electric conductivity of the conductive support 33a can be increased. It is desirable to use
[0030]
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.
[0031]
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.
[0032]
Further, it is desirable to provide a current collecting film 33g made of a P-type semiconductor, 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 current collector film 33g made of a P-type semiconductor 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.
[0033]
The fuel side electrode 33b provided on the main surface of the conductive support 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.
[0034]
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.
[0035]
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.
[0036]
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.
[0037]
The interconnector 33f is a dense body to prevent leakage of fuel gas and oxygen-containing gas inside and outside the conductive support 33a, and the inner and outer surfaces of the interconnector 33f are in contact with the fuel gas and oxygen-containing gas. Therefore, it has reduction resistance and oxidation resistance.
[0038]
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.
[0039]
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.
[0040]
The conductive support 33a and the fuel-side electrode 33b described above can be replaced with a fuel-side electrode that also serves as a conventionally used support. That is, the conductive support 33a and the fuel side electrode 33b may be formed of, for example, a fuel side electrode made of Ni and YSZ.
[0041]
In the fuel cell 33 of the present invention, as shown in FIG. 1, in the fuel cell 33, the diameter of the gas flow path 34 in the thickness direction is R1, and the diameter of the gas flow path 34 in the direction orthogonal to the thickness direction is R2. At this time, the relationship of R2> R1 is satisfied. That is, the shape of the gas channel 34 is a shape that is crushed in the thickness direction, and is also expressed as a wide shape in a direction orthogonal to the thickness direction.
[0042]
By making the gas flow path 34 have the above-described shape, the stress due to the shrinkage concentrated on the thinnest portion B at the time of firing is relieved, and cracking of the thinnest portion B frequently occurring at the time of firing can be suppressed. It was.
[0043]
Further, by forming the gas flow path 34 in the above-described shape, it is possible to prevent the thinnest portion B from being cracked, which is slightly generated even during power generation.
[0044]
Moreover, the crack of the thinnest part B can be suppressed more effectively by making the ratio of R2 and R1 1.03 times or more.
[0045]
In addition to satisfying the relationship of R2> R1, the shape of the gas channel 34 is such that the inner wall of the gas channel 34 closest to the flat part a is a flat part in order to relieve stress applied to the thinnest part B. it is preferably formed a a flat row.
[0046]
The manufacturing method of the fuel cell 33 as described above will be described. First, rare earth element oxide powder excluding La, Ce, Pr, and Nd elements and Ni and / or NiO powder are mixed, and an electroconductive support material in which an organic binder and a solvent are mixed is extruded into this mixed powder. It shape | molds and produces a plate-shaped electroconductive support body molded object, This is dried and degreased.
[0047]
For example, when the shape of the pin for forming the gas flow path 34 of the extrusion molding die is a wide shape, R2> R1 can be easily satisfied.
[0048]
When the conductive support molded body is dried, it is desirable to sandwich the conductive support molded body from both sides with a load plate 40 as shown in FIG.
[0049]
The load plate 40 is desirably porous in order to volatilize the solvent. In addition, friction is generated between the conductive support molded body and the load plate 40, and in order to suppress drying shrinkage in the width direction of the conductive support 33a, the side of the load plate 40 in contact with the conductive support molded body. The surface is preferably a rough surface.
[0050]
Further, the material forming the load plate 40 is preferably made of a component contained in the conductive support 33a so as not to adversely affect the material even if it adheres to the conductive support molded body. If the weight of the load plate 40 is sufficient, the weight 42 need not necessarily be placed.
[0051]
As mentioned above, in order to fully exhibit the described effect, the load applied to the conductive support molded body is preferably 1 g / cm ² or more, and more preferably 2.5 g / cm ² or more.
[0052]
Moreover, as for drying conditions, it is desirable to dry for 2 hours or more in the temperature range of 80 degreeC-150 degreeC. Furthermore, after drying, calcination is performed in a temperature range of 800 to 1100 ° C.
[0053]
Next, a slurry to be a fuel-side electrode molded body prepared by mixing Ni and / or NiO powder, a ZrO ₂ powder in which a rare earth element is dissolved, an organic binder, and a solvent is prepared.
[0054]
Next, a slurry to be the fuel-side electrode molded body is applied to the surface of the one side flat portion a of the conductive support molded body so as to have a thickness of 2 to 10 μm using a mesh plate making, and a temperature of 80 to 150 ° C. Dry at temperature.
[0055]
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 is applied to the surface of the one side flat surface of the conductive support molded body. It is covered and wound so that the surfaces to which the slurry is applied are in contact with each other and both end surfaces of the solid electrolyte molded body are spaced apart from each other by a flat surface on the other side, and dried at a temperature of 80 to 150 ° C.
[0056]
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.
[0057]
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. .
[0058]
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 conductive support molded body.
[0059]
Thus, the fuel-side electrode molded body and the solid electrolyte molded body are sequentially laminated on the surface of the one flat portion a of the conductive support molded body, and the intermediate film molded body and the interconnector are stacked on the surface of the other flat portion a. A laminated molded body in which the molded bodies are laminated is produced. 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.
[0060]
Next, the multilayer molded body is degreased and cofired at 1300 to 1600 ° C. in an oxygen-containing atmosphere.
[0061]
Next, a transition metal perovskite oxide powder, which is a P-type semiconductor, and a solvent are mixed to prepare a paste. The laminate is immersed in the paste, and oxygen is deposited 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 side electrode molded body and the current collector film molded body by dipping, or by direct spray coating and baking at 1000 to 1300 ° C.
[0062]
In addition, since the Ni component in the conductive support 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 thereafter conductive support 33a. A reducing fuel gas is flowed from the side, and NiO is reduced at 800 to 1000 ° C. Further, this reduction process may be performed during power generation.
[0063]
As shown in FIG. 3, the cell stack is composed of a plurality of fuel battery cells 33, and a metal felt and / or a metal plate is interposed between one fuel battery cell 33 and the other fuel battery cell 33. The conductive support 33a of one fuel cell 33 is interposed between the intermediate film 33e, the interconnector 33f, the current collection film 33g, and the current collection member 43 provided on the conductive support 33a. And is electrically connected to the oxygen side electrode 33d of the other fuel cell 33.
[0064]
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.
[0065]
Reference numeral 42 denotes a conductive member for connecting the fuel cells in series.
[0066]
The fuel cell of the present invention is configured by storing the cell stack of FIG. 3 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 discharged out of the storage container.
[0067]
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.
[0068]
Further, the conductive support 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 conductive support 33a and the inner electrode 33b are replaced with the inner electrode also serving as the support.
[0069]
Of course, various methods may be used for forming the oxygen side electrode 33d and the current collecting film 33g.
[0070]
【Example】
First, NiO powder is mixed to 48 volume% in terms of Ni metal, and Y ₂ O ₃ powder is mixed to 52 volume%. To this mixture, a pore agent, an organic binder composed of a cellulose-based binder, and a solvent composed of water And the mixed conductive support material was extrusion molded to produce a plate-shaped conductive support molded body.
[0071]
In the extrusion molding, the hole shape of the conductive support molded body was changed so that R1 and R2 had the ratio shown in Table 1. These conductive support molded bodies were dried under conditions of 130 ° C.
[0072]
Using this conductive support molded body, the conductive support molded body was processed so as to have a length of 200 mm after firing, and calcined at 1000 ° C.
[0073]
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.
[0074]
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.
[0075]
The slurry to be the fuel-side electrode molded body was applied to the surface of one flat surface of the conductive support molded body to a thickness of 5 μm using a mesh plate and dried at a temperature of 130 ° C.
[0076]
Further, the slurry to be the fuel-side electrode molded body was screen-printed on the solid electrolyte molded body so as to have a thickness of 10 μm after firing and dried at a temperature of 130 ° C.
[0077]
Next, the surface on the side where the slurry of the solid electrolyte molded body coated with the slurry to be the fuel side electrode molded body is applied to the flat surface on one side of the conductive support molded body on which the fuel side electrode molded body is formed. Was wound so that both ends thereof were separated from each other by a flat surface on the other side, and dried.
[0078]
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.
[0079]
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. .
[0080]
Next, the sheet-like interconnector molded body was laminated so that the surface coated with the slurry was in contact with the exposed conductive support molded body.
[0081]
Next, this laminate was subjected to binder removal treatment and co-fired at 1500 ° C. in the air.
[0082]
Next, an oxygen-side electrode slurry was 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 was calcined to form a solid electrolyte sheet. The surface of the molded body is sprayed to form an oxygen-side electrode molded body, and the slurry is applied to the outer surface of the fired interconnector 33 f and baked at 1150 ° C. to form the oxygen-side electrode 33 d and the interconnector 33 f A current collecting film 33g was formed on the outer surface of the fuel cell, and a fuel battery cell 33 of the present invention as shown in FIG. 1 was produced.
[0083]
Note that the conductive support 33a has a major axis (distance in the direction between mm) of 26 mm and a minor axis of 3.5 mm (distance in the direction between a and a), and is formed between the fuel side electrode 33b and the oxygen side electrode 33d. The thickness of the solid electrolyte 33c was 40 μm, the thickness of the oxygen side electrode 33d was 50 μm, the thickness of the fuel side electrode 33b was 10 μm, the thickness of the interconnector 33f was 50 μm, and the thickness of the current collecting film 33g was 50 μm. Further, 15 mm non-power generation portions were formed at both ends of each fuel cell 33.
[0084]
Next, hydrogen gas was allowed to flow inside the fuel cell 33, and the conductive support 33a and the fuel side electrode 33b were subjected to reduction treatment at 850 ° C.
[0085]
Fuel gas is circulated through the gas flow path 34 of the obtained fuel battery cell 33, oxygen-containing gas is circulated outside the fuel battery cell 33, and the fuel battery cell 33 is heated to 850 ° C. using a gas burner to generate power. A test was conducted.
[0086]
Regarding the thinnest part B in the flat part a of the fuel battery cell 33, the presence or absence of cracks or delamination that occurred during R2 / R1 simultaneous firing, final firing, reduction, or power generation test was shown in Table 1. .
[0087]
In addition, 40 samples after co-firing were produced under each condition.
[0088]
[Table 1]

[0089]
As shown in Table 1, R2 / R1 = 1 of the fuel battery cell 33, and sample No. In No. 1, out of 40 samples, there were defects due to cracking of 8 during simultaneous firing, 4 during final firing, 4 during reduction, and 2 during power generation test. Eventually, cracks and cracks are confirmed in the thinnest wall portion B of the 18 fuel cells 33 out of 40, and it can be seen that the yield is low and the reliability of the fuel cells 33 is also low.
[0090]
On the other hand, the sample No. 1 of the present invention in which R2 / R1 is 1.03. In No. 2, there were six cracks that occurred during simultaneous firing, final firing, reduction, and power generation test, and the occurrence of defects could be halved. In addition, the occurrence of cracks during the power generation test could not be confirmed, and the reliability was greatly improved.
[0091]
In addition, sample No. 1 of the present invention in which R2 / R1 is 1.10. In No. 3, there were three cracks that occurred during simultaneous firing, final firing, reduction, and power generation test, which can greatly reduce the occurrence of defects, and there is no crack during power generation test, and reliability is improved. Greatly improved.
[0092]
Further, the sample No. 1 of the present invention in which R2 / R1 is 1.26 or more. In Nos. 3 to 7, cracks that occurred during simultaneous firing, final firing, reduction, and power generation test were all zero, and the occurrence of defects could be suppressed, and the reliability could be greatly improved.
[0093]
【The invention's effect】
According to the present invention, it is possible to provide a fuel cell, a fuel cell, and a method for manufacturing the same that have high yield and excellent reliability.
[Brief description of the drawings]
FIG. 1 is a cross-sectional perspective view showing a fuel battery cell of the present invention.
FIG. 2 is a cross-sectional view showing a method for drying a conductive support according to the present invention.
FIG. 3 is a cross-sectional view showing a cell stack of the present invention.
FIG. 4 is a cross-sectional view showing a conventional fuel cell.
[Explanation of symbols]
33 ... Fuel cell 33a ... Conductive support 33b ... Inner electrode, fuel side electrode 33c ... Solid electrolyte 33d ... Outer electrode, oxygen side electrode 34 ... Gas flow path R1. ..Gas channel diameter R2 in the thickness direction of the conductive support R2 ... Gas channel diameter in the direction orthogonal to the thickness of the conductive support

Claims (4)

A fuel- side electrode, a solid electrolyte, and an oxygen- side electrode are sequentially provided on one side main surface of a plate-like conductive support formed with a plurality of gas flow paths to form a power generation unit, and the other side main surface a fuel cell formed by providing the interconnector, the gas flow path in the elliptical shape, the diameter of the gas flow path in the thickness direction of the plate-shaped conductive support R1, the plate-like conductive A fuel cell, wherein R2> R1 is satisfied, where R2 is a diameter of the gas flow path in a direction orthogonal to the thickness of the support. A power source is formed by sequentially providing a solid electrolyte and an oxygen side electrode on one side main surface of a fuel side electrode that also serves as a plate-like support having a plurality of gas flow paths , and on the other side main surface. a fuel cell formed by providing the interconnector, the gas flow path in the elliptical shape, the diameter of the gas passage in the thickness direction of the fuel-side electrode serves as the plate-like support R1, the plate-like A fuel cell, wherein R2> R1 is satisfied, where R2 is a diameter of a gas flow path in a direction orthogonal to the thickness of the fuel- side electrode serving also as a support.   3. The fuel cell according to claim 1, wherein R2 is 1.03 times or more of R1. Fuel cell characterized by comprising a plurality accommodated in the accommodation container the fuel cell according to any one of claims 1 to 3.

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