JP5818656B2 - Solid oxide fuel cell, cell stack device, fuel cell module and fuel cell device - Google Patents

Description

  The present invention relates to a solid oxide fuel cell having a conductive support, an interconnector, a fuel electrode layer, a solid electrolyte layer, and an oxygen electrode layer, a cell stack device, a fuel cell module, and a fuel cell device. .

  In recent years, various fuel cell modules in which a cell stack device in which a plurality of fuel cells are electrically connected in series are accommodated in a storage container have been proposed as next-generation energy.

  As a fuel cell constituting such a cell stack device, a porous fuel electrode layer, a dense fuel cell is formed on one main surface of a conductive support having a fuel gas passage for flowing a fuel gas inside. A solid electrolyte layer and an oxygen electrode layer are laminated in this order, and an intermediate layer and a dense interconnector are provided on the main surface on the other side, and both ends of the solid electrolyte layer are on the main surface on the other side. There has been proposed a structure in which both ends of the solid electrolyte layer and both ends of the interconnector are joined via an intermediate layer (see Patent Document 1).

  In such a fuel cell, the solid electrolyte layer is caused by a difference in thermal expansion between the intermediate layer and the interconnector, or reduction contraction accompanying reduction of the iron group metal oxide contained in the intermediate layer into an iron group metal. And the interconnector may peel off. As a result, the fuel gas inside the fuel cell may leak from between the solid electrolyte layer and the interconnector layer.

  Therefore, in recent years, the intermediate layer is formed only on the conductive support located between both ends of the solid electrolyte layer, and both ends of the interconnector in the circumferential direction (width direction) of the fuel cell are connected to the width of the fuel cell. A fuel cell that is directly bonded to both ends of the solid electrolyte layer in the direction has been developed (see Patent Document 2).

JP 2005-158529 A JP 2011-113830 A

However, it is difficult to form the intermediate layer only on the conductive support located between the both ends of the solid electrolyte layer, and the intermediate layer is formed at a distance from both ends of the solid electrolyte layer. However, in this case, there is a space between the interconnector disposed on the intermediate layer and on both ends of the solid electrolyte layer, and the conductive support, and between the intermediate layer end and the solid electrolyte layer end. As a result of long-term power generation, cracks are generated along the space, causing gas leaks, and the long-term reliability of the fuel cell may be reduced.

  An object of the present invention is to provide a solid oxide fuel cell, a cell stack, a fuel cell module, and a fuel cell device that can improve long-term reliability.

In the solid oxide fuel cell of the present invention, an intermediate layer extending in the longitudinal direction and a portion of the intermediate layer of the conductive support are formed around a part of a columnar conductive support. An inner electrode layer provided in a portion not provided, a solid electrolyte layer provided so as to cover the inner electrode layer and having both ends separated from both ends of the intermediate layer, and provided on the solid electrolyte layer An outer electrode layer; and an interconnector provided on the intermediate layer so that both end portions thereof overlap with both end portions of the solid electrolyte layer, and a part of the interconnector is formed of the solid electrolyte layer. Provided on the conductive support between both ends and both ends of the intermediate layer, the distance between both ends of the solid electrolyte layer and both ends of the intermediate layer is a ratio to the width of the conductive support. but, that is 0.13 or more and not more than 0.014 And butterflies.

The solid oxide fuel cell of the present invention includes an intermediate layer provided in a part of the periphery of a columnar conductive support and extending in the longitudinal direction, and the intermediate layer around the conductive support. A fuel electrode layer provided in a portion where the fuel electrode layer is not formed, a solid electrolyte layer provided so as to cover the fuel electrode layer and having both ends separated from both ends of the intermediate layer, and on the solid electrolyte layer An outer electrode provided on the intermediate layer, and an interconnector provided so that both ends thereof overlap with both ends of the solid electrolyte layer, and both ends of the solid electrolyte layer and the intermediate layer Dense ceramics are provided on the conductive support between both ends of the solid electrolyte layer, and the distance between both ends of the solid electrolyte layer and both ends of the intermediate layer has a ratio to the width of the conductive support. , especially that 0.13 inclusive 0.014 To.

  In the solid oxide fuel cell of the present invention, a part of the interconnector is provided on the conductive support between both ends of the solid electrolyte layer and both ends of the intermediate layer, or both ends of the solid electrolyte layer. A dense ceramic is provided on the conductive support between the both ends of the intermediate layer and the intermediate layer. A part of the interconnector or a dense ceramic is provided between the both ends of the solid electrolyte layer and the both ends of the intermediate layer. Therefore, the conventional space is not formed, and thereby, generation of cracks and the like in the fuel cell can be suppressed, gas leakage can be suppressed, and long-term reliability of the fuel cell can be improved. Further, by providing the fuel cell described above, a cell stack device, a fuel cell module, and a fuel cell device with improved long-term reliability can be obtained.

An example of a fuel cell is shown, (a) is the cross-sectional view, (b) is a perspective view of (a). It is the side view seen from the interconnector side of a fuel cell. An example of a cell stack apparatus is shown, (a) is a side view schematically showing the cell stack apparatus, and (b) is an enlarged cross-sectional view of a part surrounded by a dotted frame of the cell stack apparatus of (a). is there. It is an external appearance perspective view which shows an example of a fuel cell module. It is a disassembled perspective view which shows an example of a fuel cell apparatus. It is a cross-sectional view of a fuel cell showing a state in which a dense ceramic is disposed on a conductive support between both ends of a solid electrolyte layer and both ends of an intermediate layer.

  1A and 1B show an embodiment of a fuel cell, where FIG. 1A is a cross-sectional view and FIG. 1B is a perspective view of FIG. In both drawings, each configuration of the fuel cell 1 is partially enlarged. Further, the same reference numerals are assigned to the same members.

  The fuel cell 1 has a hollow flat plate shape, and includes a conductive support 2 having an elliptical column shape as a whole. The conductive support 2 can also be referred to as an elongated plate. A plurality of fuel gas passages 7 penetrating from one end to the other end in the longitudinal direction L are formed in the conductive support 2 at predetermined intervals, and the fuel cell 1 is disposed on the conductive support 2. Has a structure in which various members are provided.

  As understood from the shape shown in FIG. 1, the conductive support 2 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.

  On one flat surface n of the conductive support 2, an intermediate layer 9 and a dense interconnector 6 are provided from one end to the other end in the longitudinal direction L of the conductive support 2, and the interconnector 6 is provided. A fuel electrode layer 3 that is a porous inner electrode on the other flat surface n and both side surfaces m, a dense solid electrolyte layer 4 that covers the outer surface of the fuel electrode layer 3, and a porous outer electrode A laminated body in which the oxygen electrode layer 5 is laminated is provided. In the fuel cell 1 shown in FIG. 1, the fuel electrode layer 3 (more specifically, the interconnector 6) is disposed on the solid electrolyte layer 4 on the other main surface of the conductive support 2 via the diffusion prevention layer 8. The oxygen electrode layer 5 is laminated so as to face each other. Further, in the following description, the inner electrode is described as the fuel electrode layer 3 and the outer electrode is described as the oxygen electrode layer 5.

  In the fuel cell 1, as shown in FIGS. 1 and 2, the fuel electrode layer 3 and the solid electrolyte layer 4 are connected to one main surface from the other main surface via arcuate surfaces m at both ends. The connector 6 extends to both sides in the circumferential direction (width direction W) of the fuel cell 1, both ends of the intermediate layer 9 provided on one flat surface n, the fuel electrode layer 3 and the solid electrolyte layer 4. The conductive support 2 between the both ends of the intermediate layer 9 and the both ends of the fuel electrode layer 3 and the solid electrolyte layer 4 is provided with a part 6a of the interconnector 6 at a predetermined interval. Has been placed.

  In other words, the intermediate layer 9 is formed to extend in the longitudinal direction L of the conductive support 2 as shown in FIG. As shown in FIG. 1, both ends of the width direction W are connected to both ends of the fuel electrode layer 3 extending to the one flat surface n via the arcuate surface m of the conductive support 2, and the fuel electrode. The solid electrolyte layer 4 formed so as to cover the layer 3 is separated from both ends of the solid electrolyte layer 4 with a predetermined distance S, both ends of the fuel electrode layer 3, both ends of the solid electrolyte layer 4, and both ends of the intermediate layer 9 A part 6a of the interconnector 6 is disposed between the two.

  That is, as will be described later, the slurry containing the material forming the interconnector 6 is applied to the upper surface of the intermediate layer 9 and the upper surfaces of both end portions of the solid electrolyte layer 4, whereby the upper surface of the intermediate layer 9, the solid electrolyte layer 4 The slurry for forming the interconnector 6 is applied to the conductive support 2 between both ends of the fuel electrode layer 3 and the solid electrolyte layer 4 and both ends of the intermediate layer 9 as well as the upper surfaces of both ends of A part 6 a of the interconnector 6 is disposed on the conductive support 2 between both ends of the intermediate layer 9 and both ends of the fuel electrode layer 3 and the solid electrolyte layer 4.

  The interconnector 6 is superposed on and joined to the upper surface of the intermediate layer 9, the upper surface of the dense ceramic 6 a, and the upper surfaces of both ends of the solid electrolyte layer 4. The intermediate layer 9 and the fuel electrode layer 3 contain at least one of Ni and NiO.

The distance S between both ends of the fuel electrode layer 3, both ends of the solid electrolyte layer 4, and both ends of the intermediate layer 9 is not particularly limited as long as it is a distance that can form a part 6 a of the interconnector 6. However, in particular, the ratio of the distance S to the width of the conductive support is preferably 0.014 or more from the viewpoint of pouring the slurry forming the interconnector 6, and the reaction between the interconnector 6 and the conductive support 2 is desirable. In view of improving the bonding strength between the interconnector 6 and the conductive support 2 while suppressing the above, it is preferably 0.13 or less. For example, when the width of the conductive support is 30 mm, it is preferably 0.5 to 2 mm.

  The fuel electrode layer 3 may be provided only in the region of the conductive support 2 facing the oxygen electrode layer 5, and the other regions of the conductive support 2 may be covered with the solid electrolyte layer 4.

  Here, the fuel battery cell 1 generates power when the facing portions of the fuel electrode layer 3 and the oxygen electrode layer 5 function as electrodes. That is, an oxygen-containing gas such as air is allowed to flow outside the oxygen electrode layer 5 and a fuel gas (hydrogen-containing gas) is allowed to flow through the fuel gas passage 7 in the conductive support 2 to be heated to a predetermined operating temperature. To generate electricity. The current generated by the power generation is collected through an interconnector 6 provided on the surface of the conductive support 2.

  Below, each member which comprises the fuel cell 1 of this embodiment is demonstrated.

  Since the conductive support 2 is required to be gas permeable in order to allow the fuel gas to pass to the fuel electrode layer 3 and to be conductive in order to collect current via the interconnector 6, For example, it is preferably formed of at least one of Ni and NiO and an inorganic oxide, particularly a specific rare earth oxide.

The specific rare earth oxide is used to make the thermal expansion coefficient of the conductive support 2 close to the thermal expansion coefficient of the solid electrolyte layer 4, and is Y, Lu (lutetium), Yb, Tm (thulium). A rare earth oxide containing at least one element selected from the group consisting of Er, Er (erbium), Ho (holmium), Dy (dysprosium), Gd, Sm, and Pr (praseodymium), at least one of Ni and NiO Can be used in combination. Specific examples of such rare earth oxides include Y ₂ O ₃ , Lu ₂ O ₃ , Yb ₂ O ₃ , Tm ₂ O ₃ , Er ₂ O ₃ , Ho ₂ O ₃ , Dy ₂ O ₃ , Gd ₂ O. ₃ , Sm ₂ O ₃ , Pr ₂ O ₃ can be exemplified, and there is almost no solid solution or reaction with at least one of Ni and NiO, and the thermal expansion coefficient is comparable to that of the solid electrolyte layer 4. And Y ₂ O ₃ and Yb ₂ O ₃ are preferable because they are inexpensive.

Further, in the present embodiment, the volume ratio after firing-reduction is Ni: rare earth in that the good conductivity of the conductive support 2 is maintained and the thermal expansion coefficient is approximated to that of the solid electrolyte layer 4. It is preferable that the element oxide (for example, Ni: Y ₂ O ₃ ) is in the range of 35:65 to 65:35 (Ni / (Ni + Y) is 65 to 86 mol% in molar ratio). In addition, the electroconductive support body 2 does not need to contain the said specific rare earth oxide, and may contain another inorganic oxide. The conductive support 2 may contain other metal components and oxide components as long as required characteristics are not impaired.

  Moreover, since the electroconductive support body 2 needs to have gas permeability, it is preferable that the porosity is 30% or more, particularly 35 to 50%. The conductivity of the conductive support 2 is 50 S / cm or more, more preferably 300 S / cm or more, and particularly preferably 440 S / cm or more.

  The length of the flat surface n of the conductive support 2 (length in the width direction W of the conductive support 2) is 15 to 35 mm, and the length of the arcuate surface m (arc length) is 2 to 2. The thickness of the conductive support 2 (thickness between the flat surfaces n) is preferably 1.5 to 5 mm.

The fuel electrode layer 3 causes an electrode reaction, and can be formed from at least one of Ni and NiO, which are iron group metals, and ZrO _{2 in} which a rare earth element is dissolved. In addition, as a rare earth element, the rare earth elements (Y etc.) illustrated in the electroconductive support body 2 can be used.

In the fuel electrode layer 3, and at least one of Ni and NiO, ZrO ₂ content of the rare earth element is solid-solved is fired - volume ratio after reduction, Ni: ZrO ₂ (e.g. a rare earth element in solid solution, NiO: YSZ) is preferably in the range of 35:65 to 65:35. Further, the 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.

The solid electrolyte layer 4 uses a dense ceramic made of partially stabilized or stabilized ZrO ₂ containing rare earth elements such as 3 to 15 mol% of Y (yttrium), Sc (scandium), Yb (ytterbium). Is preferred. 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. The solid electrolyte layer 4 is not limited to a zirconia type, and may be a lanthanum gallate type solid electrolyte, for example.

  In addition, the solid electrolyte layer 4 and the oxygen electrode layer 5 are firmly joined between the solid electrolyte layer 4 and the oxygen electrode layer 5 described later, and the components of the solid electrolyte layer 4 and the oxygen electrode layer 5 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 fuel, and the fuel cell 1 shown in FIG. Show.

Here, the diffusion prevention layer 8 can be formed with a composition containing Ce (cerium) and another rare earth element. For example, (CeO ₂ ) _1-x (REO _1.5 ) _x (RE is It is preferably at least one of Sm, Y, Yb, and Gd, and x 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 diffusion prevention layer 8 can be composed of, for example, two layers. In this case, after the first layer is provided by simultaneous firing with the solid electrolyte layer 4, the second layer is formed at a temperature lower by 200 ° C. or more than the simultaneous firing. It is preferable to fire separately.

  Further, the oxygen electrode layer 5 needs to have gas permeability. Therefore, the conductive ceramic (perovskite oxide) forming the oxygen electrode layer 5 has a porosity of 20% or more, particularly 30 to 50%. It is preferable to be in the range. Furthermore, the thickness of the oxygen electrode layer 5 is preferably 30 to 100 μm from the viewpoint of current collection.

The interconnector 6 is preferably formed of conductive ceramics, but is required to have reduction resistance and oxidation resistance because it contacts the fuel gas (hydrogen-containing gas) and the oxygen-containing gas. . For this reason, lanthanum chromite-based perovskite oxides (LaCrO ₃ -based oxides) are generally used as conductive ceramics having reduction resistance and oxidation resistance. In particular, the conductive support 2 and the solid electrolyte layer 4 are used. LaCrO ₃ -based oxides are used for the purpose of bringing the coefficient of thermal expansion closer to the above. The interconnector 6 is not limited to LaCrO ₃ type oxide.

  Further, the thickness of the interconnector 6 is preferably 10 to 50 μm from the viewpoint of prevention of gas leakage and electrical resistance. If the thickness is smaller than this range, gas leakage is liable to occur. If the thickness is larger than this range, the electric resistance is large, and the current collecting function may be lowered due to a potential drop.

  Furthermore, between the electroconductive support body 2 and the interconnector 6, while suppressing the reaction of the interconnector 6 and the electroconductive support body 2, the joining strength of the interconnector 6 and the electroconductive support body 2 is improved. An intermediate layer 9 is provided for this purpose. The thickness of the intermediate layer 9 is preferably 5 to 20 μm.

The intermediate layer 9 is made of an inorganic oxide such as a rare earth element oxide or ZrO ₂ in which a rare earth element is dissolved.
In addition, it can be configured to contain at least one of CeO ₂ in which a rare earth element is dissolved and at least one of Ni and NiO. More specifically, for example, a composition comprising at least one of Y ₂ O ₃ and Ni and NiO, a composition comprising at least one of ZrO ₂ (YSZ) in which Y is solid-solved, Ni and NiO, Y, Sm, It can be formed from a composition comprising CeO ₂ in which Gd or the like is dissolved, and at least one of Ni and NiO. Note that the rare earth element oxide or rare earth element ZrO ₂ (CeO ₂ ) and at least one of Ni and NiO have a volume ratio in the range of 40:60 to 60:40 after firing and reduction. It is preferable to form as follows.

  Although not shown, it is preferable to provide a P-type semiconductor layer on the outer surface (upper surface) of the interconnector 6. By connecting the current collecting member to the interconnector 6 via the P-type semiconductor layer, the contact between the two becomes an ohmic contact, the potential drop can be reduced, and the deterioration of the current collecting performance can be effectively avoided. .

As such a P-type semiconductor layer, a layer made of a transition metal perovskite oxide can be exemplified. Specifically, P having a high electron conductivity, for example, P made of at least one kind of LaMnO ₃ -based oxide, LaFeO ₃ -based oxide, LaCoO ₃ -based oxide in which Mn, Fe, Co, etc. exist at the B site. Type semiconductor ceramics can be used. In general, the thickness of such a P-type semiconductor layer is preferably in the range of 30 to 100 μm.

  By the way, in the conventional fuel cell, during production of the fuel cell or during reduction treatment, the solid electrolyte layer, the intermediate layer formed between both ends of the solid electrolyte layer, the fuel electrode layer, and the interconnector When both ends of the solid electrolyte layer peel off from the interconnector due to thermal expansion differences or reduction contraction caused by reduction of iron group metal oxides contained in the intermediate layer and fuel electrode layer to iron group metals There is a risk that the fuel gas flowing through the fuel gas flow path provided inside the fuel cell leaks and the long-term reliability of the fuel cell decreases.

  On the other hand, in the fuel cell 1 shown in FIG. 1, both end portions of the interconnector 6 in the circumferential direction (width direction W) of the fuel cell 1 are both end portions of the solid electrolyte layer 4 in the width direction W of the fuel cell 1. Therefore, the fuel gas can be prevented from leaking from between both ends of the solid electrolyte layer 4 and both ends of the interconnector 6. Therefore, the long-term reliability of the fuel cell 1 can be improved.

Further, both ends of the intermediate layer 9 and both ends of the fuel electrode layer 3 and the solid electrolyte layer 4 are separated by a predetermined distance S, and both ends of the intermediate layer 9 and both ends of the fuel electrode layer 3 and the solid electrolyte layer 4 are separated. Since the part 6a of the interconnector 6 is disposed in the conductive support 2 between the two, the space is not formed between both ends of the solid electrolyte layer 4 and both ends of the intermediate layer 9, Thereby, generation | occurrence | production of the crack etc. in the fuel cell 1 can be suppressed, and the long-term reliability of the fuel cell 1 can be improved.

  A method for manufacturing the fuel cell 1 of the present embodiment described above will be described.

First, a clay is prepared by mixing at least one of Ni and NiO, a powder of a rare earth oxide such as Y ₂ O ₃ , an organic binder, and a solvent, and extrusion molding is performed using the clay. The conductive support 2 molded body is prepared by the above, and dried. In addition, as the conductive support 2 molded body, a calcined body obtained by calcining the conductive support 2 molded body at 900 to 1000 ° C. for 2 to 6 hours may be used.

Subsequently, an intermediate layer 9 molded body 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 or the like is added to adjust the intermediate layer slurry. The adjusted intermediate layer slurry is applied to one side main surface of the conductive support 2 molded body so as to extend in the longitudinal direction L and dried to form the intermediate layer 9 molded body.

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, the mixed powder is mixed with an organic binder and a solvent to prepare a slurry for the fuel electrode layer 3.

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 4 compact is produced. The slurry for the fuel electrode layer 3 is applied on the obtained sheet-shaped solid electrolyte layer 4 molded body to form a laminated body formed with the fuel electrode layer 3 molded body. The electrode layer 3 molded body is used as the lower surface and extends from the other side main surface of the conductive support 2 molded body through the side surface to one side main surface, and both ends of the fuel electrode layer 3 molded body and the solid electrolyte layer 4 molded body are Then, the intermediate layer 9 is laminated so as to be separated from both ends of the formed body in the width direction W with a predetermined interval S therebetween.

Subsequently, a formed diffusion prevention layer 8 formed between the solid electrolyte layer 4 and the oxygen electrode layer 5 is formed. For example, CeO ₂ powder in which GdO _1.5 is dissolved is subjected to heat treatment at 800 to 900 ° C. for 2 to 6 hours, and then wet crushed to adjust the aggregation degree to 5 to 35, thereby preventing the diffusion preventing layer 8 The raw material powder for the compact is adjusted. The wet crushing is desirably ball milled for 10 to 20 hours using a solvent. The same applies to the case where the diffusion prevention layer 8 is formed from CeO ₂ powder in which SmO _1.5 is dissolved.

  Then, toluene is added as a solvent to the raw material powder of the diffusion prevention layer 8 molded body having a coagulation degree prepared to produce a slurry for the diffusion prevention layer 8, and this slurry is applied onto the solid electrolyte layer 4 molded body. A molded article for diffusion prevention layer 8 is prepared. Alternatively, a sheet-shaped diffusion preventing layer 8 molded body may be produced and laminated on the solid electrolyte layer 4 molded body.

Subsequently, a material for the interconnector 6 (for example, LaCrMgO ₃ -based oxide powder), an organic binder, and a solvent are mixed to prepare a slurry, and this slurry is mixed with the upper surface of both ends of the solid electrolyte layer 4 and the intermediate layer 9. It is applied between the upper surface of the molded body, both ends of the intermediate layer 9 molded body, both ends of the solid electrolyte layer 4 molded body, and both ends of the fuel electrode layer 3 molded body to form the interconnector 6 molded body.

  Subsequently, the above-mentioned laminated molded body is subjected to a binder removal treatment, and is simultaneously sintered (co-fired) at 1400 ° C. to 1600 ° C. for 2 to 6 hours in an oxygen-containing atmosphere.

Next, a slurry containing a material for the oxygen electrode layer 5 (for example, LaCoO ₃ oxide powder), a solvent, and a pore increasing agent is applied onto the diffusion prevention layer 8 by dipping or the like. Further, a slurry containing a P-type semiconductor layer material (for example, LaCoO ₃ oxide powder) and a solvent, if necessary, is applied to a predetermined position of the interconnector 6 by dipping or the like. Then, the fuel cell 1 of the present embodiment having the structure shown in FIG. 1 can be manufactured by baking at 1000 to 1300 ° C. for 2 to 6 hours. In addition, it is preferable that the fuel cell 1 thereafter causes hydrogen gas to flow therein to perform reduction treatment of the conductive support 2 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.

  As described above, in the fuel cell 1 of the present embodiment, the conductive support 2 is sealed with the dense interconnector 6 and the dense solid electrolyte layer 4 so that the fuel gas is conductively supported. Leakage from the body 2, the fuel electrode layer 3 and the intermediate layer 9 can be suppressed. Thereby, it can be set as the fuel cell 1 with improved long-term reliability.

  FIG. 3 shows an example of a cell stack device configured by electrically connecting a plurality of the above-described fuel cells 1 in series via a current collecting member 14, and (a) shows a cell stack. The side view which shows the stack apparatus 12 roughly, (b) is a partial expanded sectional view of the cell stack apparatus 12 of (a), and extracts and shows the part enclosed with the dotted-line frame shown in (a). Yes. In addition, in (b), in order to clarify, the part corresponding to the part enclosed with the dotted-line frame shown by (a) is shown with the arrow.

  In the cell stack device 12, each fuel battery cell 1 is arranged via a current collecting member 14 to constitute a cell stack 13, and the lower end portion of each fuel battery cell 1 is connected to the fuel battery cell 1. It is fixed to the manifold 15 for supplying the fuel gas with an adhesive such as a glass sealing material. In addition, the cell stack 13 is sandwiched from both ends in the arrangement direction of the fuel cells 1 by the elastically deformable conductive member 16 whose lower end is fixed to the manifold 15.

  Further, in the conductive member 16 shown in FIG. 3, a current for drawing out a current generated by power generation of the cell stack 13 (fuel cell 1) in a shape extending outward along the arrangement direction of the fuel cells 1. A drawer portion 17 is provided.

  Here, in the cell stack device 12 of the present embodiment, the above-described fuel cell 1 is used to form the cell stack 13, thereby sealing with the dense interconnector 6 and the dense solid electrolyte layer 4. Therefore, the fuel gas can be prevented from leaking, and the cell stack device 12 with improved long-term reliability can be obtained.

  FIG. 4 is an external perspective view showing an example of the fuel cell module 20 in which the cell stack device 12 of the present embodiment is stored in a storage container, and is shown in FIG. 4 inside a rectangular parallelepiped storage container 21. The cell stack device 12 is accommodated.

  In order to obtain fuel gas used in the fuel cell 1, a reformer 22 for reforming raw fuel such as natural gas or kerosene to generate fuel gas is disposed above the cell stack 13. ing. The fuel gas generated by the reformer 22 is supplied to the manifold 15 via the gas flow pipe 23 and supplied to the fuel gas flow path 7 provided inside the fuel battery cell 1 via the manifold 15. The

  FIG. 4 shows a state in which a part (front and rear surfaces) of the storage container 21 is removed and the cell stack device 12 and the reformer 22 housed inside are taken out rearward. Here, in the fuel cell module 20 shown in FIG. 4, the cell stack device 12 can be slid and stored in the storage container 21. The cell stack device 12 may include a reformer 22.

  In addition, the oxygen-containing gas introduction member 24 provided inside the storage container 21 is disposed between a pair of cell stacks 13 juxtaposed to the manifold 15 in FIG. 4, 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 1 so that the side of the fuel cell 1 flows from the lower end toward the upper end. And the temperature of the fuel cell 1 can be raised by burning the fuel gas and the oxygen-containing gas discharged from the fuel gas channel 7 of the fuel cell 1 on the upper end side of the fuel cell 1. The activation of the cell stack device 12 can be accelerated. In addition, by burning the fuel gas and the oxygen-containing gas discharged from the fuel gas flow path 7 of the fuel cell 1 on the upper end side of the fuel cell 1, the fuel cell 1 (cell stack 13) The reformer 22 disposed above can be efficiently heated. Thereby, the reforming reaction can be efficiently performed in the reformer 22.

  FIG. 5 is an exploded view showing an example of the fuel cell device of the present embodiment in which the fuel cell module 20 shown in FIG. 4 and an auxiliary machine for operating the fuel cell stack device 12 are housed in an outer case. It is a perspective view. In FIG. 5, a part of the configuration is omitted.

  A fuel cell device 25 shown in FIG. 5 has a module housing chamber 29 in which an inside of an exterior case composed of a support column 26 and an exterior plate 27 is vertically divided by a partition plate 28 and the upper side thereof accommodates the fuel cell module 20 described above. The lower side is configured as an auxiliary equipment storage chamber 30 for storing auxiliary equipment for operating the fuel cell module 20. It should be noted that auxiliary equipment stored in the auxiliary equipment storage chamber 28 is omitted.

  Further, the partition plate 28 is provided with an air circulation port 31 for flowing the air in the auxiliary machine storage chamber 30 to the module storage chamber 29 side, and a part of the exterior plate 27 constituting the module storage chamber 29 An exhaust port 32 for exhausting air in the module storage chamber 29 is provided.

  In such a fuel cell device 25, as described above, the fuel cell module 20 capable of improving long-term reliability is housed in the module housing chamber 29, so that the fuel with improved long-term reliability is provided. The battery device 25 can be obtained.

  Although the present invention has been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and improvements can be made without departing from the scope of the present invention. For example, in the fuel cell 1 of the present embodiment, the hollow flat plate is shown, but the present invention can also be used in a cylindrical fuel cell.

  Further, in the above embodiment, both ends of the intermediate layer 9 and both ends of the fuel electrode layer 3 and the solid electrolyte layer 4 are separated by a predetermined distance S, and both ends of the intermediate layer 9, the fuel electrode layer 3 and the solid electrolyte layer are separated. In the conductive support 2 between the both ends of 4, the case where the part 6 a of the interconnector 6 is disposed has been described. However, as shown in FIG. 6, both ends of the intermediate layer 9 and the fuel electrode layer 3 and a dense ceramic 46 made of a material different from that of the interconnector 6 may be disposed on the conductive support 2 between both ends of the solid electrolyte layer 4.

  In such a fuel cell 1, a slurry containing a material for forming the dense ceramic 46 is applied between both ends of the fuel electrode layer 3, both ends of the solid electrolyte layer 4, and both ends of the intermediate layer 9. Thereafter, the material for forming the interconnector 6 can be formed by applying and baking the upper surface of both ends of the solid electrolyte layer 4, the upper surface of the intermediate layer 9, and the upper surface of the dense ceramic 46.

  The dense ceramic 46 contains a composition similar to the interconnector 6, for example, lanthanum zirconate or lanthanum aluminate, a material constituting the solid electrolyte 4, or a composition similar to the solid electrolyte 4, stronzirconate, Sc. Zirconia and other materials such as alumina can be used. The density of the dense ceramic 46 may be about the same as that of the interconnector 6.

  In the above-described embodiment, the fuel cell 1 in which the inner electrode is the fuel electrode layer 3 and the outer electrode is the oxygen electrode layer 5 has been described. For example, the inner electrode is the oxygen electrode layer 5 and the outer electrode is the fuel. It can also be set as the fuel cell made into the polar layer 3. FIG.

1: Fuel cell 2: Conductive support 3: Fuel electrode layer 4: Solid electrolyte layer 5: Oxygen electrode layer 6: Interconnector 6a: Part of interconnector 9: Intermediate layer 12: Cell stack device 20: Fuel cell Module 25: Fuel cell device 46: Dense ceramics

Claims (6)

An intermediate layer provided extending in the longitudinal direction on a part of the periphery of the columnar conductive support; an inner electrode layer provided on a portion of the conductive support where the intermediate layer is not formed; A solid electrolyte layer provided so as to cover the inner electrode layer and having both ends separated from both ends of the intermediate layer; an outer electrode layer provided on the solid electrolyte layer; and the intermediate layer; And an interconnector provided so that both end portions overlap with both end portions of the solid electrolyte layer, and a part of the interconnector is provided between the both ends of the solid electrolyte layer and the intermediate layer. Provided on a conductive support ,
The solid oxide fuel characterized in that the distance between both ends of the solid electrolyte layer and both ends of the intermediate layer has a ratio to the width of the conductive support of 0.014 or more and 0.13 or less. Battery cell. An intermediate layer provided extending in the longitudinal direction on a part of the periphery of the columnar conductive support; an inner electrode layer provided on a portion of the conductive support where the intermediate layer is not formed; A solid electrolyte layer provided so as to cover the inner electrode layer and having both ends separated from both ends of the intermediate layer; an outer electrode layer provided on the solid electrolyte layer; and the intermediate layer; An interconnector provided so that both end portions overlap with both end portions of the solid electrolyte layer, and the conductive support between the both ends of the solid electrolyte layer and the intermediate layer is dense ceramics Is provided ,
The solid oxide fuel characterized in that the distance between both ends of the solid electrolyte layer and both ends of the intermediate layer has a ratio to the width of the conductive support of 0.014 or more and 0.13 or less. Battery cell.   The intermediate layer and the interconnector are provided on one main surface of the flat conductive support, and the inner electrode layer, the solid electrolyte layer, and the outer electrode layer are provided on the other main surface. Each of the inner electrode layer and the solid electrolyte layer is extended from the other main surface of the conductive support to the one main surface via the side surface. The solid oxide fuel cell according to claim 1, wherein the fuel cell is a solid oxide fuel cell.   A cell stack comprising a plurality of the solid oxide fuel cells according to any one of claims 1 to 3 arranged via a current collecting member and electrically connected in series.   A fuel cell module comprising the cell stack according to claim 4 housed in a housing container.   6. A fuel cell device comprising: the fuel cell module according to claim 5; and an auxiliary machine for operating the fuel cell module, housed in an outer case.

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