JP2012181927A - Solid oxide fuel cell and fuel cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid oxide fuel cell which has adequate electric conduction between a conductive support and an interconnector, and is provided with the interconnector which has high bonding strength to an intermediate layer, and to provide a fuel cell module.SOLUTION: The solid oxide fuel cell comprises: a conductive support 1 that contains an inorganic oxide except ZrO, and Ni; a power generation part provided with a fuel electrode layer 3, a solid electrolyte layer 4 and an air electrode layer 6 which are provided on the conductive support 1; and an interconnector 8 which is made of a perovskite oxide containing La and provided on a portion of the conductive support 1 at which the power generation part is not provided. A plurality of intermediate layers 7 containing Zr is formed between the conductive support 1 and the interconnector 8 with a predetermined space.

Description

  The present invention relates to a solid oxide fuel cell and a fuel cell module, and in particular, a conductive support is provided with a power generation unit, and La is provided on a portion of the conductive support that is not provided with the power generation unit. The present invention relates to a solid oxide fuel cell and a fuel cell module provided with an interconnector made of a perovskite oxide.

  In recent years, various fuel cell modules in which solid oxide fuel cells are accommodated in a storage container have been proposed as next-generation energy.

  As such a solid oxide fuel cell, a conductive support having a pair of flat surfaces parallel to each other, a fuel gas passage for allowing fuel gas to circulate therein, and containing Ni A solid oxide fuel cell has been proposed in which a fuel electrode layer, a solid electrolyte layer, and an air electrode layer are laminated in this order on a flat surface on one side, and an interconnector is laminated on the flat surface on the other side. (For example, refer to Patent Document 1).

  A fuel cell stack device in which a plurality of such solid oxide fuel cells are electrically connected via a current collecting member has been proposed (for example, see Patent Document 2).

Conventionally, a solid oxide fuel cell has a solid electrolyte layer formed of a dense ZrO ₂ based sintered body formed so as to surround the conductive support, and a dense electrolyte at both ends of the solid electrolyte layer. Bonding both ends of interconnector made of _high quality LaCrO ₃ system sintered body, connecting the conductive support and interconnector via an intermediate layer, and conducting by the solid electrolyte layer and interconnector The fuel gas that surrounds the periphery of the support in an airtight manner and passes through the inside of the conductive support is configured not to leak outside from the space formed by the solid electrolyte layer and the interconnector.

  As the intermediate layer, a sintered body formed of Ni or NiO and zirconia or rare earth element oxide in which a rare earth element is dissolved is known (see, for example, Patent Document 3).

JP 2008-84716 A JP 2008-135304 A JP 2004-265734 A

However, in an intermediate layer formed of Ni or NiO and zirconia in which a rare earth element is dissolved, La from an interconnector made of a LaCrO ₃ based sintered body formed on the upper surface reacts with Zr of the intermediate layer. Although lanthanum zirconate can be formed at the interface and the interconnect strength of the interconnector to the intermediate layer can be improved, the electrical resistance of lanthanum zirconate is large, thus inhibiting conduction between the conductive support and the interconnector, The power generation performance of the solid oxide fuel cell may be reduced.

In addition, when an intermediate layer formed of Ni or NiO and a rare earth element oxide is formed between the conductive support and the interconnector, electrical resistance is provided between the intermediate layer and the conductive support. Since a reaction product such as lanthanum zirconate having a low thickness is not formed, the electrical connection between the conductive support and the interconnector is good, but the bonding strength of the interconnector to the intermediate layer may be lowered.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a solid oxide fuel cell and a fuel cell module that have good conduction between a conductive support and an interconnector and have high bonding strength to an intermediate layer of the interconnector. .

The solid oxide fuel cell of the present invention is provided with a power generation unit including a fuel electrode layer, a solid electrolyte layer, and an air electrode layer on a conductive support containing an inorganic oxide other than ZrO ₂ and Ni. A solid oxide fuel cell in which an interconnector made of a perovskite oxide containing La is provided in a portion of the conductive support not provided with the power generation unit, A plurality of intermediate layers containing Zr are formed at a predetermined interval between the conductive support and the interconnector.

  The fuel cell module of the present invention is characterized in that the solid oxide fuel cell is accommodated in a storage container.

The solid oxide fuel cell of the present invention includes a Zr between a conductive support containing an inorganic oxide excluding ZrO ₂ and Ni and an interconnector made of a perovskite oxide containing La. Are formed at predetermined intervals, lanthanum zirconate is generated between the intermediate layer and the interconnector, and the bonding strength between the intermediate layer and the interconnector can be improved, In the portion where the intermediate layer is not formed, lanthanum zirconate having a large electric resistance is not generated between the conductive support and the interconnector, so that high conduction can be maintained between the conductive support and the interconnector. Thereby, in the part in which the intermediate layer is formed, the bonding strength between the conductive support and the interconnector can be maintained high, and in the part in which the intermediate layer is not formed, between the conductive support and the interconnector. High electrical continuity can be maintained by reducing the electrical resistance.

FIG. 2 shows a solid oxide fuel cell, in which (a) is a cross-sectional view, and (b) is a side view of the state where illustration of an interconnector is omitted. The intermediate layer is shown in a state in which the intermediate layer is formed at both ends in the length direction of the conductive support at a higher density than the central portion in the length direction of the conductive support, and the side surface in which the description of the interconnector is omitted FIG. An example of a fuel cell stack device is shown, (a) is a side view schematically showing the fuel cell stack device, (b) is a part of a portion surrounded by a broken line of the fuel cell stack device of (a). It is sectional drawing shown. It is an external appearance perspective view which shows an example of a fuel cell module. It is a perspective view which abbreviate | omits and shows a part of fuel cell apparatus.

  FIG. 1 shows an example of a solid oxide fuel cell (hereinafter abbreviated as “fuel cell”) according to the present embodiment, in which (a) is a cross-sectional view and (b) is an island in FIG. It is the side view which abbreviate | omitted description of the interconnector so that the intermediate | middle layer formed in multiple numbers may become clear. In both drawings, each configuration of the fuel cell 10 is partially enlarged. Further, FIG. 1B is illustrated in a reduced size in the length direction, and actually has a shape that is long in the vertical direction.

This fuel cell 10 is a hollow plate type fuel cell 10 having a flat cross section and an overall elliptical cylindrical shape, and containing a porous conductive material containing Ni and an inorganic oxide excluding ZrO _2. The support 1 is provided. A plurality of fuel gas flow paths 2 are formed in the longitudinal direction in the conductive support 1 at appropriate intervals, and the fuel cell 10 is provided with various members on the conductive support 1. Have a structure.

  As understood from the shape shown in FIG. 1, the conductive support 1 is composed of a pair of flat surfaces n parallel to each other and arcuate surfaces (side surfaces) m connecting the pair of flat surfaces n. Has been. Both surfaces of the flat surface n are formed substantially parallel to each other, and a porous fuel electrode layer 3 is provided so as to cover one flat surface n (lower surface) and the arcuate surfaces m on both sides. A dense solid electrolyte layer 4 is laminated so as to cover the electrode layer 3. A porous air electrode layer 6 is laminated on the solid electrolyte layer 4 so as to face the fuel electrode layer 3 with the reaction preventing layer 5 interposed therebetween.

  The fuel electrode layer 3, the solid electrolyte layer 4, the reaction preventing layer 5, and the air electrode layer 6 constitute a power generation unit, and this power generation unit is provided on the conductive support 1. The conductive support 1 has a fuel gas flow path 2 for circulating fuel gas therein, and the conductive support 1 is hermetically surrounded by the solid electrolyte layer 4 and the interconnector 8.

The fuel electrode layer 3 and the solid electrolyte layer 4 are formed to the other flat surface n (upper surface) via the arcuate surfaces m at both ends, and are formed at both ends of the solid electrolyte layer 4 made of a ZrO ₂ based sintered body. Both ends of the interconnector 8 made of LaCrO ₃ sintered body are joined via the joining layer 9 made of sintered body, the conductive support 1 is surrounded by the solid electrolyte layer 4 and the interconnector 8, and the inside is distributed. The fuel gas is configured not to leak to the outside.

  In other words, the interconnector 8 having a rectangular planar shape is formed from the upper end to the lower end of the conductive support 1, and both left and right end portions thereof are formed on the surfaces of both end portions of the solid electrolyte layer 4 that are open. 9 is joined.

  A plurality of intermediate layers 7 are formed at predetermined intervals on the other flat surface n (upper surface) where the fuel electrode layer 3 and the solid electrolyte layer 4 are not laminated, and an interconnector 8 containing La is further formed. The plurality of intermediate layers 7 are formed in an island shape between the conductive support 1 and the interconnector 8.

  The plurality of intermediate layers 7 have a disk shape, and are arranged in a matrix of 5 in the cell length direction and 6 in the horizontal direction, as shown in FIG. 1B. The layers 7 are formed at a predetermined interval from each other. The number and arrangement can be set freely. The intermediate layer 7 may have a main surface that is not circular, but may be, for example, a polygon such as a triangle or a quadrangle, or may be an ellipse.

The intermediate layer 7 contains Zr. In particular, it is desirable to contain Ni and ZrO _{2 in} which a rare earth element is dissolved. For example, the content of Ni or NiO is preferably 65 to 35% by volume. Further, these intermediate layers 7 are preferably dense, and the thickness is preferably 7 to 13 μm. The intermediate layer 7 contains Ni and ZrO _{2 in} which a rare earth element is dissolved, but may also contain a rare earth element oxide such as Y ₂ O ₃ .

Ni is not always necessary, but it is desirable to contain Ni in order to improve the bonding strength with the conductive support 1. Furthermore, Fe or Co can be contained instead of Ni or together with Ni. A lanthanum zirconate layer is formed between the intermediate layer 7 and the interconnector 8.

In such a fuel cell, an intermediate layer 7 containing a plurality of Ni and ZrO _{2 in} which a rare earth element is dissolved is formed at a predetermined interval between the conductive support 1 and the interconnector 8. Therefore, lanthanum zirconate is generated between the intermediate layer 7 and the surface of the interconnector 8 with which the intermediate layer 7 is in contact, and the bonding strength between the intermediate layer 7 and the interconnector 8 can be improved.

  On the other hand, a portion where the intermediate layer 7 is not formed, that is, a portion where the interconnector 8 is directly formed on the surface of the conductive support 1 is an electric resistance between the conductive support 1 and the interconnector 8. Since a large lanthanum zirconate is not generated, the conduction between the conductive support 1 and the interconnector 8 can be maintained high.

  Thereby, in the part in which the intermediate layer 7 is formed, the bonding strength between the conductive support 1 and the interconnector 8 can be improved, and in the part in which the intermediate layer 7 is not formed, the conductive support 1 and the interconnector. Conductivity can be improved by reducing the electrical resistance between the two.

  It is desirable that the intermediate layer 7 has a dome-shaped shape on the interconnector 8 side. Thereby, it becomes possible to relieve the stress resulting from the difference in thermal expansion between the respective materials, and the intermediate layer can be formed stably.

  In the fuel cell 10, the portion where the fuel electrode layer 3 and the air electrode layer 6 face each other through the solid electrolyte layer 4 functions as an electrode to generate electric power. That is, an oxygen-containing gas such as air is allowed to flow outside the air electrode layer 6, and a fuel gas (hydrogen-containing gas) is allowed to flow through the fuel gas passage 2 in the conductive support 1 to be heated to a predetermined operating temperature. To generate electricity. And the electric current produced | generated by this electric power generation is collected through the interconnector 8 attached to the electroconductive support body 1. FIG.

  Below, each member which comprises the fuel cell 10 of this form is demonstrated.

The conductive support 1 is required to be gas permeable in order to allow the fuel gas to permeate to the fuel electrode layer 3 and to be conductive in order to collect current via the interconnector 8. For example, it is preferably formed of Ni and an inorganic oxide other than ZrO ₂ , such as a specific rare earth oxide.
Examples of the inorganic oxide other than the ZrO _2, is not particularly limited as long as non-ZrO _2, in which hardly reacts viewpoint of thermal expansion coefficient, and the constituent elements of the interconnector 8 as follows.

The specific rare earth oxide is used to bring the thermal expansion coefficient of the conductive support 1 close to the thermal expansion coefficient of the solid electrolyte layer 4, and is Y, Lu, Yb, Tm, Er, Ho, Dy. Rare earth oxides containing at least one element selected from the group consisting of, Gd, Sm and Pr can be used in combination with Ni and / or NiO. 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, there is almost no solid solution and reaction with Ni and / or NiO, the thermal expansion coefficient is the same as that of the solid electrolyte layer 4, and From the point of being cheap, Y ₂ O ₃ and Yb ₂ O ₃ are preferable.

In the present embodiment, Ni and / or NiO: rare earth oxide = 35: 65 in terms of maintaining good conductivity of the conductive support 1 and approximating the thermal expansion coefficient to that of the solid electrolyte layer 4. It is preferably present in a volume ratio of ~ 65: 35. The conductive support 1 may contain other metal components and oxide components as long as required characteristics are not impaired.

  Moreover, since the electroconductive support 1 needs to have fuel gas permeability, it is usually preferable that the open porosity is 30% or more, particularly 35 to 50%. The conductivity of the conductive support 1 is preferably 300 S / cm or more, and particularly preferably 440 S / cm or more.

  Note that the length of the flat surface n of the conductive support 1 (length in the width direction of the conductive support 1) is usually 15 to 35 mm, and the length of the arc-shaped surface m (arc length) is 2. The thickness of the conductive support 1 (thickness between the flat surfaces n) is preferably 1.5 to 5 mm. The length of the conductive support 1 is 100 to 150 mm.

The fuel electrode layer 3 causes an electrode reaction, and is preferably formed of a known porous conductive ceramic. For example, it can be formed of ZrO _{2 in which a} rare earth element is dissolved or CeO _{2 in} which a rare earth element is dissolved, and Ni and / or NiO. As the rare earth element, the rare earth elements exemplified in the conductive support 1 can be used. For example, the rare earth element can be formed from ZrO ₂ (YSZ) in which Y is dissolved, and Ni and / or NiO.

The content of ZrO ₂ in which the rare earth element is dissolved in the fuel electrode layer 3 or CeO ₂ in which the rare earth element is dissolved is preferably in the range of 35 to 65% by volume, and the content of Ni or NiO Is preferably 65 to 35% by volume. Further, the open porosity of the fuel electrode layer 3 is preferably 15% or more, particularly preferably in the range of 20 to 40%, and the thickness thereof is preferably 1 to 30 μm.

  Further, since the fuel electrode layer 3 only needs to be formed at a position facing the air electrode layer 6, for example, the fuel electrode layer 3 is formed only on the flat surface n on the side where the air electrode layer 6 is provided. May be. That is, the fuel electrode layer 3 is provided only on the flat surface n, the solid electrolyte layer 4 is on the fuel electrode layer 3, the arcuate surfaces m of the conductive support 1, and the other flat surface on which the fuel electrode layer 3 is not formed. It may have a structure formed on the surface n.

The solid electrolyte layer 4 is preferably 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, Sc or Yb. As the rare earth element, Y is preferable because it is inexpensive. Further, the solid electrolyte layer 4 is desirably a dense material having a relative density (according to Archimedes method) of 93% or more, particularly 95% or more in terms of preventing gas permeation, and a thickness of 5 to 50 μm. Preferably there is.

  It should be noted that the solid electrolyte layer 4 and the air electrode layer 6 are firmly joined between the solid electrolyte layer 4 and the air electrode layer 6 described later, and the components of the solid electrolyte layer 4 and the air electrode layer 6 are 1 may be provided for the purpose of suppressing the formation of a reaction layer having a high electrical resistance due to the reaction of the reaction, and the fuel cell 10 shown in FIG. Show.

Here, the reaction preventing layer 5 can be formed with a composition containing Ce and another rare earth element other than Ce. For example, (CeO ₂ ) _1-x (REO _1.5 ) _x (formula Among these, RE is preferably at least one of Sm, Y, Yb, and Gd, and x preferably has a composition represented by 0 <x ≦ 0.3. Furthermore, from the viewpoint of reducing electrical resistance, it is preferable to use Sm or Gd as RE, for example, it is preferably made of CeO ₂ in which 10 to 20 mol% of SmO _1.5 or GdO _1.5 is dissolved. .

The air electrode layer 6 is preferably formed of a conductive ceramic made of a so-called ABO ₃ type perovskite oxide. Such a perovskite oxide is preferably a transition metal perovskite oxide, in particular at least one of LaMnO ₃ oxide, LaFeO ₃ oxide, and LaCoO ₃ oxide in which Sr and La coexist at the A site. 600 From the viewpoint of high electrical conductivity at an operating temperature of about ˜1000 ° C., LaCoO ₃ oxides are particularly preferable. In the perovskite oxide, Fe and Mn may exist together with Co at the B site.

  Further, the air electrode layer 6 needs to have gas permeability. Therefore, the conductive ceramic (perovskite oxide) forming the air electrode layer 6 has an open porosity of 20% or more, particularly 30 to 50%. It is preferable that it exists in the range. Furthermore, the thickness of the air electrode layer 6 is preferably 30 to 100 μm from the viewpoint of current collection.

  An interconnector 8 is laminated on the flat surface n of the conductive support 1 opposite to the air electrode layer 6 via an intermediate layer 7.

The interconnector 8 is formed of a conductive ceramic made of a perovskite oxide containing La. In order to come into contact with fuel gas (hydrogen-containing gas) and oxygen-containing gas, it is necessary to have reduction resistance and oxidation resistance. For this reason, as a conductive ceramic having reduction resistance and oxidation resistance, for example, a perovskite oxide (LaCrO ₃ oxide or LaTiO ₃ oxide) containing La and Cr or Ti is used. Can do. In order to approximate the thermal expansion coefficients of the conductive support 1 and the solid electrolyte layer 4, a LaCrMgO ₃ -based oxide in which Mg is present at the B site can be used.

  The thickness of the interconnector 8 is preferably 10 to 50 μm from the viewpoint of preventing gas leakage and electrical resistance. Within this range, gas leakage can be prevented and electrical resistance can be reduced.

  Both end portions of the interconnector 8 are joined to both end portions of the solid electrolyte layer 4 via the joining layer 9.

  An example of a method for manufacturing the fuel battery cell 10 of the present embodiment described above will be described.

First, for example, Ni and / or NiO powder, a rare earth oxide powder such as Y ₂ O ₃ , an organic binder, and a solvent are mixed to prepare a clay, and this clay is used for extrusion molding. A conductive support molded body is prepared and dried. In addition, as the conductive support molded body, a calcined body obtained by calcining the conductive support molded body at 900 to 1000 ° C. for 2 to 6 hours may be used.

Next, the raw material of ZrO ₂ (YSZ) in which NiO and Y ₂ O ₃ are dissolved, for example, is weighed and mixed according to a predetermined composition. Thereafter, an organic binder and a solvent are mixed with the mixed powder to prepare a slurry for the fuel electrode layer.

Further, a slurry obtained by adding toluene, a binder, a commercially available dispersant, etc. to a ZrO ₂ powder in which a rare earth element is solid-solubilized is molded to a thickness of 7 to 75 μm by a method such as a doctor blade. A solid electrolyte layer molded body is produced. The fuel electrode layer slurry is applied on the obtained sheet-shaped solid electrolyte layer molded body to form a fuel electrode layer molded body, and the surface on the fuel electrode layer molded body side is laminated on the conductive support molded body. The slurry for the fuel electrode layer may be applied to a predetermined position of the conductive support molded body and dried, and the solid electrolyte layer molded body may be laminated on the conductive support molded body (fuel electrode layer molded body).

  Subsequently, a reaction preventing layer 5 disposed between the solid electrolyte layer 4 and the air electrode layer 6 is formed.

For example, CeO ₂ powder in which GdO _1.5 is dissolved is heat-treated at 800 to 900 ° C. for 2 to 6 hours to prepare a raw material powder for a reaction preventing layer molded body.

  Then, toluene is added as a solvent to the raw material powder of the reaction prevention layer molded body to produce a slurry for the intermediate layer, and this slurry is applied onto the solid electrolyte layer molded body to form a coating film of the reaction prevention layer, A molded body is produced. In addition, a sheet-like molded body may be produced and laminated on the solid electrolyte layer molded body.

Subsequently, a material for an interconnector (for example, LaCrMgO ₃ oxide powder), an organic binder, and a solvent are mixed to prepare a slurry, and an interconnector sheet is prepared.

Subsequently, an intermediate layer molded body positioned between the conductive support 1 and the interconnector 8 is formed. For example, ZrO ₂ in which Y is dissolved and NiO are mixed and dried so that the volume ratio is in the range of 40:60 to 60:40, and an organic binder is added to adjust the slurry for the intermediate layer. An intermediate layer molded body is formed by applying to the support molded body. Since the intermediate layer is formed in a number of island shapes, the intermediate layer formed body is formed in a matrix as shown in FIG. 1B, for example, by screen printing in order to form a plurality of island shapes.

Thereafter, for example, a bonding layer forming material composed of 50 to 68 mol% of MgO, 30 to 47 mol% of Y ₂ O _3, and ₃ to 5 mol% of La ₂ O ₃ , an organic binder and a solvent are mixed. A slurry is prepared, and this slurry is applied to both ends of the solid electrolyte layer molded body to produce a bonded layer molded body, and the end of the interconnector sheet is laminated on the bonded layer molded body. In the same manner, the laminated molded body is produced by laminating on the conductive support molded body on which the intermediate layer molded body is formed.

  Next, the above-mentioned laminated molded body is subjected to binder removal treatment, and is simultaneously sintered (simultaneously fired) in an oxygen-containing atmosphere at 1400 to 1450 ° C. for 2 to 6 hours.

Further, a slurry containing an air electrode layer material (for example, LaCoO ₃ oxide powder), a solvent and a pore-forming agent is applied on the reaction preventing layer by dipping or the like, and baked at 1000 to 1300 ° C. for 2 to 6 hours. Thereby, the fuel cell 10 of this embodiment having the structure shown in FIG. 1 can be manufactured. In addition, it is preferable that the fuel cell 10 thereafter causes hydrogen gas to flow therein to perform reduction treatment of the conductive support 1 and the fuel electrode layer 3. In that case, it is preferable to perform a reduction process at 750-1000 degreeC for 5 to 20 hours, for example.

  FIG. 3 shows an example of a fuel cell stack device configured by electrically connecting a plurality of the above-described fuel cells 10 in series via a current collecting member 13. Is a side view schematically showing the fuel cell stack device 11, (b) is a partially enlarged cross-sectional view of the fuel cell stack device 11 of (a), the portion surrounded by the broken line shown in (a) An excerpt is shown. In addition, in (b), the part corresponding to the part enclosed by the broken line shown in (a) is shown by an arrow, and in the fuel cell 10 shown in (b), the intermediate layer described above is shown. 7 and some members such as the reaction preventing layer 5 are omitted.

In the fuel cell stack device 11, the fuel cell stack 12 is configured by arranging the fuel cells 10 via the current collecting members 13, and the lower end of each fuel cell 10 is a fuel cell. The gas tank 16 for supplying the fuel gas to the battery cell 10 is fixed with an adhesive such as a glass sealing material. In addition, an elastically deformable conductive member 14 having a lower end fixed to the gas tank 16 is provided so as to sandwich the fuel cell stack 12 from both ends in the arrangement direction of the fuel cells 10 via the current collecting members 13. Yes.

  Further, in the conductive member 14 shown in FIG. 3, in order to draw out the current generated by the power generation of the fuel cell stack 12 (fuel cell 10) in a shape extending outward along the arrangement direction of the fuel cells 10. Current extraction part 15 is provided.

  Here, in the fuel cell stack device 11 of this embodiment, the fuel cell stack device 11 having improved long-term reliability is obtained by configuring the fuel cell stack 12 using the fuel cell 10 described above. be able to.

  In the fuel cell stack device 11 shown in FIG. 3, the lower end of the fuel cell 10 is fixed to a gas tank 16 for supplying fuel gas to the fuel cell 10 with an adhesive such as a glass sealing material, The adhesive and the interconnector layer 8 of the fuel battery cell 10 have different expansion coefficients, and stress is likely to act on the interconnector layer 8 in the fixed part. Also, the fuel gas is present at the upper end of the fuel battery cell 10. Therefore, strong bonding strength is required between the conductive support 1 and the interconnector layer 8.

  Therefore, as shown in FIG. 2, the intermediate layer 7 has a higher density at both ends in the length direction of the conductive support 1 (vertical direction in FIG. 2) than the central portion in the length direction of the conductive support 1. It is desirable to be formed with. Thus, by increasing the formation density of the intermediate layer 7 at both ends in the length direction of the conductive support 1, the conductive support 1 and the conductive support 1 at both ends in the length direction of the conductive support 1. The bonding strength with the interconnector layer 8 can be improved.

  On the other hand, the power generation unit in which the fuel electrode layer 3, the solid electrolyte layer 4, and the air electrode layer 6 are stacked is formed in the center in the length direction of the conductive support 1, and is formed at both ends. Therefore, the electrical conductivity between the conductive support 1 and the interconnector layer 6 can be increased due to the low formation density of the intermediate layer 7 at the central portion in the longitudinal direction of the conductive support 1, and the power generation performance Can be improved.

  That is, at both ends in the length direction of the conductive support 1, a plurality of intermediate layers 7 are formed at a higher density than the central portion in the length direction (the area of the plurality of intermediate layers with respect to a certain area of the conductive support 1). ) Is formed. The region (area) of these high-density forming portions 7a can be set as appropriate, and the formation density can also be set as appropriate.

  As for the size of one intermediate layer, for example, in the case of a disk shape, the size of the main surface is preferably 1 mm or more, but the bonding strength between the conductive support 1 and the interconnector layer 6 is improved. For this purpose, it is desirable that the diameter is small, for example, 5 mm or less.

  In FIG. 2, the high density forming portions 7 a are formed at both ends in the length direction of the conductive support 1.

  FIG. 4 is an external perspective view showing an example of the fuel cell module 18 in which the fuel cell stack device 11 is accommodated in a storage container. The fuel cell shown in FIG. The cell stack device 11 is accommodated.

  Note that a reformer 20 for reforming raw fuel such as natural gas or kerosene to generate fuel gas is provided above the fuel cell stack 12 in order to obtain fuel gas used in the fuel cell 10. It is arranged. The fuel gas generated by the reformer 20 is supplied to the gas tank 16 via the gas flow pipe 21 and supplied to the gas flow path 2 provided inside the fuel battery cell 10 via the gas tank 16. .

  FIG. 4 shows a state in which a part (front and rear surfaces) of the storage container 19 is removed and the fuel cell stack device 11 and the reformer 20 housed inside are taken out rearward. In the fuel cell module 18 shown in FIG. 4, the fuel cell stack device 11 can be slid and stored in the storage container 19. The fuel cell stack device 11 may include the reformer 20.

  Further, in FIG. 4, the oxygen-containing gas introduction member 22 provided inside the storage container 19 is disposed between the fuel cell stacks 12 juxtaposed to the gas tank 16, and the oxygen-containing gas flows into the fuel gas flow. In addition, an oxygen-containing gas is supplied to the lower end of the fuel cell 10 so that the side of the fuel cell 10 flows from the lower end toward the upper end.

  Then, the temperature of the fuel cell 10 can be increased by reacting the fuel gas discharged from the gas flow path of the fuel cell 10 with the oxygen-containing gas and burning it on the upper end side of the fuel cell 10. The start-up of the fuel cell stack device 11 can be accelerated. In addition, by burning the fuel gas and the oxygen-containing gas discharged from the gas flow path of the fuel battery cell 10 on the upper end side of the fuel battery cell 10, the fuel battery cell 10 (fuel battery cell stack 12) The reformer 20 disposed above can be warmed. Thereby, the reforming reaction can be efficiently performed in the reformer 20.

  Furthermore, in the fuel cell module 18 of this embodiment, since the fuel cell stack device 11 described above is housed in the housing container 19, the fuel cell module 18 with improved long-term reliability can be obtained.

  FIG. 5 is a perspective view showing a fuel cell device in which the fuel cell module 18 shown in FIG. 4 and an auxiliary machine for operating the fuel cell stack device 11 are housed in an outer case. In FIG. 5, a part of the configuration is omitted.

  The fuel cell device 23 shown in FIG. 5 has a module housing chamber in which an outer case made up of struts 24 and an outer plate 25 is divided into upper and lower portions by a partition plate 26 and the upper side thereof houses the fuel cell module 18 described above. 27, the lower side is configured as an auxiliary equipment storage chamber 28 for storing auxiliary equipment for operating the fuel cell module 18. In addition, auxiliary machines stored in the auxiliary machine storage chamber 28 are not shown.

  In addition, the partition plate 26 is provided with an air circulation port 29 for flowing the air in the auxiliary machine storage chamber 28 to the module storage chamber 27 side, and a part of the exterior plate 25 constituting the module storage chamber 27 An exhaust port 30 for exhausting the air in the module storage chamber 27 is provided.

  In such a fuel cell device 23, as described above, the fuel cell module 18 that can improve the reliability is housed in the module housing chamber 27, thereby improving the reliability. 23.

  As mentioned above, this invention is not limited to the above-mentioned embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention.

  For example, in the above embodiment, the hollow plate type solid oxide fuel cell has been described, but it is needless to say that it may be a cylindrical solid electrolyte fuel cell.

1: Conductive support 2: Fuel gas flow path 3: Fuel electrode layer 4: Solid electrolyte layer 5: Reaction prevention layer 6: Air electrode layer 7: Intermediate layer 8: Interconnector 11: Fuel cell stack device 18: Fuel Battery module

Claims (4)

A conductive support containing an inorganic oxide other than ZrO ₂ and Ni is provided with a power generation unit including a fuel electrode layer, a solid electrolyte layer, and an air electrode layer, and the power generation unit is not provided. A solid oxide fuel cell in which an interconnector made of a perovskite oxide containing La is provided in a portion of the electrically conductive support, and is provided between the electrically conductive support and the interconnector. A solid oxide fuel cell, wherein a plurality of intermediate layers containing Zr are formed at predetermined intervals.   The conductive support has a fuel gas passage for allowing fuel gas to flow therein, and the conductive support is hermetically surrounded by the solid electrolyte layer and the interconnector. The solid oxide fuel cell according to claim 1.   The conductive support is columnar, and the plurality of intermediate layers are formed at both ends in the length direction of the conductive support at a higher density than the central portion in the length direction of the conductive support. The solid oxide fuel cell according to claim 1, wherein the fuel cell is a solid oxide fuel cell.   A fuel cell module comprising the solid oxide fuel cell according to any one of claims 1 to 3 stored in a storage container.

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