JP2015082389A - Cell, cell stack device, module, and module storing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrolysis cell, electrolysis cell stack device, electrolysis module, and electrolytic device capable of suppressing the detachment of an interconnector layer.SOLUTION: There is provided an electrolysis cell obtained by sequentially forming a first electrode layer 3 containing Ni, a solid electrolyte layer 4 composed of ceramics, and a second electrode layer 5 on a support 1, the electrolysis cell having an interconnector layer 8 composed of a lanthanum chromite system oxide, which is electrically connected with the first electrode layer 3, provided at a portion of the support 1 where the first electrode layer is not formed, where the interconnector layer 8 is provided with an inner layer 8a on the support 1 side and an outer layer 8b provided on the outside of the inner layer 8a, and the outer layer 8b has a larger number of pores than the inner layer 8a.

Description

  The present invention relates to an electrolytic cell, an electrolytic cell stack device, an electrolytic module, and an electrolytic device.

  In recent years, various fuel cell devices have been proposed in which a cell stack device formed by electrically connecting a plurality of solid oxide fuel cells in series is accommodated in a storage container as next-generation energy.

  The solid oxide fuel cell of such a fuel cell device has a pair of flat surfaces parallel to each other, a fuel gas passage for allowing fuel gas to flow inside, and contains Ni. A conductive support is provided. Then, a solid oxide formed by laminating a fuel electrode layer, a solid electrolyte layer, and an oxygen electrode layer in this order on a flat surface on one side of the conductive support and an interconnector layer on the flat surface on the other side. A fuel cell has been proposed (see, for example, Patent Document 1).

  Conventionally, in a solid oxide fuel cell, an interconnector layer made of a lanthanum chromite oxide is bonded to a conductive support or an intermediate support layer on the conductive support. It is constructed by joining both ends of a solid electrolyte layer made of a dense zirconia oxide formed so as to surround the periphery of the interconnector so that both ends of an interconnector layer made of a dense lanthanum chromite oxide overlap. Has been.

JP 2008-84716 A

  However, in a solid oxide fuel cell, the interconnector layer made of a lanthanum chromite oxide tends to expand when exposed to a reducing atmosphere and may be peeled off from a conductive support or the like.

  An object of the present invention is to provide an electrolysis cell, an electrolysis cell stack device, an electrolysis module, and an electrolysis device that can suppress peeling of an interconnector layer.

  The electrolytic cell of the present invention is formed by sequentially forming a first electrode layer containing Ni, a solid electrolyte layer made of ceramic, and a second electrode layer on a support, and the first electrode layer of the support is formed. An interconnector layer made of a lanthanum chromite-based oxide that is electrically connected to the first electrode layer is provided in a portion that is not, and the interconnector layer includes an inner layer on the support side, and an inner layer of the inner layer. An outer layer provided on the outside, wherein the outer layer is more porous than the inner layer.

Moreover, the electrolytic cell of the present invention is formed by sequentially forming a solid electrolyte layer and a second electrode layer made of ceramics on a first electrode layer containing Ni as a support, and the solid electrolyte layer of the support is An interconnector layer made of a lanthanum chromite-based oxide that is electrically connected to the support is provided in a portion that is not formed, and the interconnector layer includes an inner layer on the support side, and an inner layer of the inner layer. An outer layer provided on the outside, wherein the outer layer is more porous than the inner layer.

  The electrolysis cell stack device of the present invention comprises a plurality of the above electrolysis cells and is electrically connected to the plurality of electrolysis cells.

  The electrolytic module of the present invention is characterized in that the electrolytic cell stack device is stored in a storage container.

  The electrolysis apparatus of the present invention is characterized in that the above-described electrolysis module and an auxiliary machine for operating the electrolysis module are housed in an outer case.

  In the electrolytic cell of the present invention, the supporter side (inner layer) of the interconnector layer is exposed to a reducing atmosphere and the outer side (outer layer) is exposed to an oxidizing atmosphere, but the outer layer is more porous than the inner layer, Oxygen penetrates deeply from the outer layer surface in the thickness direction of the interconnector layer, and the reduction of the lanthanum chromite oxide can be suppressed, so that the reduction expansion of the entire interconnector layer can be suppressed and the peeling from the support can be suppressed. .

1 shows a solid oxide fuel cell, where (a) is a cross-sectional view and (b) is a side view of (a) as viewed from the interconnector layer side. (A) is sectional drawing which expands and shows a part of interconnector layer, and its vicinity, (b) is a cross section which shows the solid oxide form fuel cell which does not form a 1st intermediate | middle layer in Fig.1 (a). FIG. It is a cross-sectional view showing a solid oxide fuel cell in which a fuel electrode layer is a support. An example of a cell stack apparatus is shown, (a) is a side view schematically showing the cell stack apparatus, (b) is an enlarged cross-sectional view showing a part of the cell stack apparatus surrounded by a broken line in (a). It is. 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 a solid oxide fuel cell (hereinafter sometimes abbreviated as a fuel cell) which is an example of an electrolysis cell, where (a) is a cross-sectional view thereof, and (b) is (a FIG. In both drawings, a part of each component of the fuel cell 10 is shown enlarged.

  The fuel battery cell 10 has a hollow flat plate type, and has a porous conductive support 1 containing Ni having a flat cross section and an elliptic cylinder shape as a whole. Inside the support 1, a plurality of fuel gas passages 2 are formed at appropriate intervals so as to penetrate in the length direction L of the fuel cell 10, and the fuel cell 10 is formed on the support 1 in various ways. It has the structure where the member of this was provided.

  As understood from the shape shown in FIG. 1, the 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. Yes. Both surfaces of the flat surface n are formed substantially parallel to each other, and are porous fuel electrode layers (first electrode layers) so as to cover one flat surface n (one main surface: lower surface) and both arc-shaped surfaces m. 3 is disposed, and a solid electrolyte layer 4 made of ceramics having gas barrier properties is disposed so as to cover the fuel electrode layer 3. The thickness of the solid electrolyte layer 4 is preferably 40 μm or less, 20 μm or less, and more preferably 15 μm or less from the viewpoint of improving power generation performance.

  A porous oxygen electrode layer (second electrode layer) 6 is disposed on the surface of the solid electrolyte layer 4 so as to face the fuel electrode layer 3 with the first intermediate layer 9 interposed therebetween. The first intermediate layer 9 is formed on the solid electrolyte layer 4 on which the oxygen electrode layer 6 is formed.

A lanthanum chromite system (LaCrO ₃ system) having gas barrier properties through the second intermediate layer 7 is formed on the other flat surface n (the other main surface: upper surface) of the support 1 on which the solid electrolyte layer 4 is not laminated. An interconnector 8 made of an oxide is formed.

  That is, the fuel electrode layer 3 and the solid electrolyte layer 4 are formed from one flat surface (one main surface: lower surface) to the other flat surface n (the other main surface: upper surface) via the arcuate surfaces m at both ends. In addition, both ends of the interconnector layer 8 are laminated and bonded to both ends of the solid electrolyte layer 4.

  That is, the solid electrolyte layer 4 having gas barrier properties and the interconnector layer 8 surround the support 1 so that fuel gas flowing through the inside does not leak to the outside. In other words, the solid electrolyte layer 4 and the interconnector layer 8 form an elliptic cylindrical body having gas barrier properties. The inside of the elliptic cylindrical body serves as a fuel gas flow path and is supplied to the fuel electrode layer 3. The fuel gas and the oxygen-containing gas supplied to the oxygen electrode layer 6 are blocked by an elliptic cylinder.

  Specifically, although not illustrated, the oxygen electrode layer 6 having a rectangular planar shape is formed except for the upper and lower ends of the support 1, while the interconnector layer 8 is formed as shown in FIG. As shown in FIG. 2, the support 1 is formed from the upper end to the lower end in the length direction L, and both end portions in the width direction W are joined to the surfaces of both end portions of the solid electrolyte layer 4.

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

  And in this embodiment, as shown to Fig.1 (a) and FIG.2 (a), the interconnector layer 8 is the outer side provided in the inner side layer 8a by the side of the support body 1, and this inner side layer 8a. And the outer layer 8b is more porous than the inner layer 8a.

  The inner layer 8a of the interconnector layer 8 has a porosity of 0.2% or less, and the outer layer 8b has a porosity of 0.3 to 2.0%. In particular, the porosity of the inner layer 8a is preferably less than 0.2%, and the porosity of the outer layer 8b is preferably 0.5 to 1.5%. The porosity can be determined with an image analysis device for a 300-fold photograph of a scanning electron microscope.

  The thickness of the interconnector layer 8 is desirably 10 to 60 μm, particularly 20 to 50 μm, and the thickness of the inner layer 8 a is 10 to 83% of the total thickness of the interconnector layer 8, particularly 50 to 83%. The thickness is desirable, and the thickness of the outer layer 8b is preferably 17 to 90% of the thickness of the entire interconnector layer 8, and particularly 17 to 50%. The inner layer 8a is preferably thicker than the outer layer 8b. Thereby, the gas barrier property and peeling by the interconnector layer 8 can be suppressed. The thickness of the inner layer 8a is preferably 3 μm or more, particularly 5 μm or more, and more preferably 10 μm or more.

  The interconnector layer 8 contains Mg and Ni, and the outer layer 8b has a smaller amount of Mg and Ni than the inner layer 8a. As a result, the outer layer 8b is less porous than the inner layer 8a, so the outer layer 8b is more porous than the inner layer 8a.

  Although the boundary between the inner layer 8a and the outer layer 8b may not be clear, when Ni and Mg are detected by wavelength dispersion X-ray microanalyzer analysis (EPMA), the inner layer 8a of the interconnector layer 8 is Since the number of outer layers 8b is extremely small compared to the inner layer 8a, the boundary can be the boundary between the inner layer 8a and the outer layer 8b. The outer layer 8b may be formed using an outer layer molded body by adding a pore-forming agent for forming pores.

In the fuel cell configured as described above, the support 1 side (inner layer 8a) of the interconnector layer 8 is exposed to a reducing atmosphere and the outer side (outer layer 8b) is exposed to an oxidizing atmosphere. Even if 8a is reduced and expanded, the outer layer 8b is more porous than the inner layer 8a, so that oxygen penetrates deeply in the thickness direction of the interconnector layer 8 from the surface of the outer layer 8b and suppresses reduction of the LaCrO ₃ system oxide. Therefore, reduction expansion of the entire interconnector layer 8 can be suppressed, and peeling from the support 1 can be suppressed.

  FIG. 2B shows a form in the case where the second intermediate layer 7 is not provided. That is, in this embodiment, the interconnector layer 8 is directly bonded to the flat surface n of the support 1. Even with such a fuel cell, the same effect as described above can be obtained.

  FIG. 3 shows a case where the fuel electrode layer becomes the support 1, but even in this case, the same effect as that of FIG. 1 can be obtained. That is, in the embodiment of FIG. 1, the fuel electrode layer 3, the solid electrolyte layer 4, and the oxygen electrode layer 6 are laminated on the support 1, but the fuel electrode layer itself is used as the support 1 as shown in FIG. The body 1 may be provided with the solid electrolyte layer 4 and the oxygen electrode layer 6.

  Below, each member which comprises the fuel cell 10 of this embodiment is demonstrated. The conductive support 1 is required to be gas permeable in order to allow fuel gas to permeate to the fuel electrode layer 3 and to be conductive in order to collect current via the interconnector layer 8. From, for example, Ni and / or NiO and an inorganic oxide such as a specific rare earth oxide.

The specific rare earth oxide is used to make the thermal expansion coefficient of the support 1 close to the thermal expansion coefficient of the solid electrolyte layer 4, and is Y, Lu, Yb, Tm, Er, Ho, Dy, Gd. Rare earth oxides containing at least one element selected from the group consisting of Sm, 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 that the good conductivity of the support 1 is maintained and the thermal expansion coefficient is approximated to that of the solid electrolyte layer 4. It is preferably present in a volume ratio of 65:35. The support 1 may contain other metal components and oxide components as long as required characteristics are not impaired.

  Further, since the support 1 is required to have fuel gas permeability, it is porous and usually has an open porosity of 25% or more, particularly 30% or more, considering the support strength. It is preferable to be in the range of 35% or less, particularly 32% or less. Further, the conductivity of the support 1 is preferably 300 S / cm or more, and particularly preferably 440 S / cm or more.

The length of the flat surface n of the support 1 (the length of the support 1 in the width direction W) is, for example, 15 to 3
The length of the arc-shaped surface m (arc length) is 2 to 8 mm, and the thickness of the support 1 (thickness between the flat surfaces n) is 1.5 to 5 mm. The length of the support 1 is, for example, 100 to 300 mm.

The fuel electrode layer 3 causes an electrode reaction, and can be formed of a well-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 oxygen electrode layer 6, for example, the fuel electrode layer only on the flat surface n on the lower side of the support 1 on which the oxygen electrode layer 6 is provided. 3 may be formed. That is, the fuel electrode layer 3 is provided only on the lower flat surface n of the support 1, the solid electrolyte layer 4 is formed on the surface of the fuel electrode layer 3, the both arcuate surfaces m of the support 1 and the fuel electrode layer 3 are formed. It may have a structure formed on the flat surface n on the upper side of the support 1 that is not.

The solid electrolyte layer 4 is preferably made of a 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. The solid electrolyte layer 4 is not limited to ceramics made of partially stabilized or stabilized ZrO _2, and may of course be a conventionally known, for example, lanthanum galade based solid electrolyte layer. .

  The solid electrolyte layer 4 and the oxygen electrode layer 6 are strongly bonded to each other between the solid electrolyte layer 4 and the oxygen electrode layer 6 described later, and the components of the solid electrolyte layer 4 react with the components of the oxygen electrode layer 6. Thus, the first intermediate layer 9 is formed for the purpose of suppressing the formation of a reaction layer having a high electrical resistance.

The first intermediate layer 9 is made of a CeO ₂ based sintered body containing a rare earth element other than Ce. For example, (CeO ₂ ) _1-x (REO _1.5 ) _x (wherein RE Is 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 oxygen electrode layer 6 is preferably formed of a conductive ceramic made of a so-called ABO ₃ type perovskite oxide. Such perovskite oxides include La-containing transition metal perovskite oxides, particularly at least one of LaMnO ₃ oxides, LaFeO ₃ oxides, and LaCoO ₃ oxides in which Sr and La coexist at the A site. LaCoO ₃ oxides are particularly preferable from the viewpoint of high electrical conductivity at an operating temperature of about 600 to 1000 ° C. In the perovskite oxide, Fe and Mn may exist together with Co at the B site.

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

The interconnector layer 8 is made of conductive ceramics. 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, conductive ceramics such as lanthanum chromite perovskite oxide (LaCrO ₃ oxide) are used as conductive ceramics having reduction resistance and oxidation resistance. For the purpose of bringing the coefficient of thermal expansion close to that of the electrolyte layer 4, LaCrO ₃ and MgO, NiO, or LaCrO ₃ oxide in which MgO and NiO are dissolved are used. In addition, MgO and NiO may be dissolved in LaCrO ₃ in some cases.

  Further, the thickness of the interconnector layer 8 is preferably 10 to 60 μm from the viewpoints of gas leakage prevention and electrical resistance. Within this range, gas leakage can be prevented and electrical resistance can be reduced.

  Further, a second intermediate layer 7 can be formed between the support 1 and the interconnector layer 8 in order to reduce the difference in thermal expansion coefficient between the interconnector layer 8 and the support 1. .

The second intermediate layer 7 can have a composition similar to that of the fuel electrode layer 3. For example, it can be formed from at least one of rare earth oxide, ZrO _{2 in which} a rare earth element is dissolved, and CeO ₂ in which a rare earth element is dissolved, and Ni and / or NiO. More specifically, for example, a composition composed of Y ₂ O ₃ and Ni and / or NiO, a composition composed of ZrO ₂ (YSZ) in which Y is solid-solved and Ni and / or NiO, Y, Sm, Gd and the like are solid. It can be formed from a composition comprising dissolved CeO ₂ and Ni and / or NiO. The volume ratio of ZrO ₂ (CeO ₂ ) in which rare earth oxide or rare earth element is dissolved and Ni and / or NiO is preferably in the range of 40:60 to 60:40.

An example of a method for producing 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 support molded body is prepared and dried. In addition, you may use the calcined body which calcined the support body molded object at 900-1000 degreeC for 2 to 6 hours as a support body molded object.

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

Then, a ZrO ₂ powder in which a rare earth element is solid-dissolved, and a slurry obtained by adding toluene, a binder powder, a commercially available dispersant, etc., are formed by a method such as a doctor blade to form a sheet-like solid electrolyte layer molded body. Make it.

  The fuel electrode layer slurry is applied onto the obtained sheet-shaped solid electrolyte layer molded body and dried to form a fuel electrode layer molded body, thereby forming a sheet-shaped laminated molded body. The surface on the fuel electrode layer molded body side of the sheet-shaped laminated molded body in which the fuel electrode layer molded body and the solid electrolyte layer molded body are laminated is laminated on a conductive support molded body to form a laminated molded body. Calcination at ~ 1200 ° C for 2-6 hours.

Subsequently, an interconnector layer material (for example, LaCrO ₃ -based oxide powder + MgO powder + NiO powder), an organic binder and a solvent are mixed to produce a slurry having a large amount of NiO and MgO and a slurry having a small amount of NiO and MgO (interlayer). Connector layer slurry).

Subsequently, a molded body of the second intermediate layer 7 located between the support 1 and the interconnector layer 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, an organic binder or the like is added to adjust the slurry for the second intermediate layer, A second intermediate layer molded body is formed by applying the solid molded body on the support molded body between both end portions of the solid electrolyte layer molded body.

Subsequently, a first intermediate layer 9 disposed between the solid electrolyte layer 4 and the oxygen 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 adjust the raw material powder for the first intermediate layer formed body. Toluene is added to the raw material powder as a solvent to prepare a first intermediate layer slurry, and this slurry is applied onto the solid electrolyte layer formed body to form a first intermediate layer formed body.

  Thereafter, the interconnector layer slurry is applied to the upper surface of the second intermediate layer molded body so that both ends of the interconnector layer molded body are laminated on both ends of the solid electrolyte molded body (calcined body). A laminated molded body is produced. At this time, first, an interconnector layer slurry containing a large amount of NiO and MgO is applied and dried to form an inner layer molded body, and then an interconnector layer slurry containing less NiO and MgO is applied onto the inner layer molded body. And drying to form an outer layer molded body, and an interconnector layer molded body is formed.

  In addition, an interconnector layer sheet in which an inner layer molded body and an outer layer molded body are laminated is prepared, and both end portions of the interconnector layer sheet are laminated on both end portions of the solid electrolyte molded body. In addition, an interconnector layer sheet may be laminated on the upper surface of the second intermediate layer molded body so that the inner layer molded body abuts on the upper surface of the second intermediate layer molded body.

  The interconnector layer sheet is formed by applying an interconnector layer slurry containing a large amount of NiO and MgO, and drying to form an inner layer molded body. Then, the interconnector layer slurry containing less Ni and Mg is formed on the inner layer molded body. And dried to form an outer layer molded body. Moreover, the sheet | seat for interconnector layers is producible also by producing an inner layer molded object and an outer layer molded object separately, respectively, and laminating | stacking these.

  Next, the above-mentioned laminated molded body is subjected to binder removal treatment, and is simultaneously sintered (co-fired) in an oxygen-containing atmosphere at 1400 to 1500 ° C., particularly at 1425 to 1475 ° C. for 2 to 6 hours.

  Since the outer layer molded body with less NiO and MgO has lower sinterability than the inner layer molded body with more NiO and MgO, the outer layer 8b becomes more porous than the inner layer 8a after simultaneous firing.

Further, a slurry containing an oxygen electrode layer material (for example, LaCoO ₃ -based oxide powder), a solvent and a pore former is applied onto the first intermediate layer by dipping or the like, and the temperature is 1000 to 1300 ° C. for 2 to 6 hours. By baking, the fuel cell 10 of this embodiment having the structure shown in FIG. 1 can be manufactured.

FIG. 4 shows an example of a cell stack device configured by electrically connecting a plurality of the above-described fuel cells 10 in series via a current collecting member 13, and (a) shows a cell stack. The side view which shows the stack | stuck apparatus 11 roughly, (b) is a partial expanded sectional view of the cell stack apparatus 11 of (a), and has extracted and shown the part enclosed with the broken line shown in (a). . In addition, in (b), the part corresponding to the part surrounded by the broken line shown in (a) is indicated by an arrow for the sake of clarity, and in the fuel cell 10 shown in (b), the above-described first Some members such as the intermediate layer 9 are omitted.

  In the cell stack device 11, each fuel battery cell 10 is arranged via a current collecting member 13 to form a cell stack 12, and the lower end portion of each fuel battery cell 10 is the fuel battery cell 10. Is fixed to a gas tank 16 for supplying fuel gas with an adhesive such as a glass sealing material. In addition, the cell stack 12 is sandwiched from both ends of the fuel cell 10 in the arrangement direction by the elastically deformable conductive member 14 whose lower end is fixed to the gas tank 16.

  Further, in the conductive member 14 shown in FIG. 4, a current for drawing out a current generated by power generation of the cell stack 12 (fuel cell 10) in a shape extending outward along the arrangement direction of the fuel cells 10. A drawer portion 15 is provided.

  The lower end portion of the fuel cell 10 is inserted into an opening formed on the upper surface of the gas tank 16, and is fixed by an adhesive such as a glass seal material.

  FIG. 5 is an external perspective view showing an example of a fuel cell module 18 in which the cell stack device 11 is stored in a storage container. The cell stack device 11 shown in FIG. It is configured to store.

  In order to obtain the fuel gas used in the fuel cell 10, a reformer 20 for reforming raw fuel such as natural gas or kerosene to generate fuel gas is disposed above the cell stack 12. ing. 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 fuel gas passage 2 provided inside the fuel cell 10 via the gas tank 16. .

  FIG. 5 shows a state in which a part (front and rear surfaces) of the storage container 19 is removed and the cell stack device 11 and the reformer 20 housed inside are taken out rearward. In the fuel cell module 18 shown in FIG. 5, the cell stack device 11 can be slid and stored in the storage container 19. The cell stack device 11 may include the reformer 20.

  Further, in FIG. 5, the oxygen-containing gas introduction member 22 provided inside the storage container 19 is disposed between a pair of cell stacks 12 juxtaposed to the gas tank 16, and the oxygen-containing gas flows into the flow of the fuel gas. 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 fuel gas passage 2 of the fuel cell 10 with the oxygen-containing gas and burning it on the upper end side of the fuel cell 10. The activation of the cell stack device 11 can be accelerated. Further, by burning the fuel gas and the oxygen-containing gas discharged from the gas passage 2 of the fuel battery cell 10 on the upper end side of the fuel battery cell 10, the fuel cell 10 is placed above the fuel battery cell 10 (cell stack 12). The arranged reformer 20 can be warmed. Thereby, the reforming reaction can be efficiently performed in the reformer 20.

  Further, in the fuel cell module 18 of the present embodiment, the cell stack device 11 using the above-described fuel cell 10 is housed in the housing container 19, so that the fuel has high power generation performance and improved long-term reliability. The battery module 18 can be obtained.

FIG. 6 shows the fuel cell module 18 shown in FIG.
1 is a perspective view showing an example of a fuel cell device that houses an auxiliary machine (not shown) for operating 1. In FIG. 6, a part of the configuration is omitted.

  A fuel cell device 23 shown in FIG. 6 has a module housing chamber in which an outer case made up of support columns 24 and an outer plate 25 is divided into upper and lower portions by a partition plate 26 and the upper side thereof stores the above-described fuel cell module 18. 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 power generation performance is high by having the fuel cell module 18 housed in the module storage chamber 27 with high power generation performance and improved reliability. The fuel cell device 23 having high reliability and improved reliability can be obtained.

  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. However, it is needless to say that a cylindrical solid oxide fuel cell may be used. Also, a so-called horizontal stripe fuel cell may be used. Furthermore, various intermediate layers may be formed between the members in accordance with the function.

Furthermore, although the fuel cell, the cell stack device, the fuel cell module, and the fuel cell device have been described in the above embodiment, the present invention is not limited to this, and steam ( It can also be applied to an electrolysis cell (SOEC) that generates hydrogen and oxygen (O ₂ ) by electrolyzing (water), and an electrolysis module and electrolysis apparatus including the electrolysis cell.

First, a NiO powder having an average particle size of 0.5 μm and a Y ₂ O ₃ powder having an average particle size of 0.9 μm are mixed, and a clay prepared with an organic binder and a solvent is molded by an extrusion molding method and dried. Degreasing was performed to produce a conductive support molded body. The volume ratio of the support molded body was 48% by volume for NiO and 52% by volume for Y ₂ O ₃ .

Next, a slurry obtained by mixing an organic binder and a solvent with ZrO ₂ powder (solid electrolyte layer raw material powder) having a particle diameter of 0.8 μm by a microtrack method in which 8 mol% of Y ₂ O ₃ is dissolved. Was used to prepare a solid electrolyte layer sheet by a doctor blade method.

The slurry for forming the first intermediate layer formed body was made of a composite oxide containing 90 mol% of CeO ₂ and 10 mol% of rare earth element oxide (GdO _1.5 , SmO _1.5 ) as an isopropyl solvent. Using an alcohol (IPA), pulverize with a vibration mill or a ball mill, calcinate at 900 ° C. for 4 hours, pulverize again with a ball mill, and adjust the degree of aggregation of ceramic particles. A binder and a solvent were added and mixed.

Next, a slurry for the fuel electrode layer is prepared by mixing the NiO powder having an average particle size of 0.5 μm, the ZrO ₂ powder in which Y ₂ O ₃ is dissolved, an organic binder, and a solvent, and screen-printed on the solid electrolyte layer sheet. It was applied by the method and dried to form a fuel electrode layer molded body.

  A sheet-like laminated molded body in which the fuel electrode layer molded body was formed on the solid electrolyte layer sheet was laminated at a predetermined position of the support molded body with the surface on the fuel electrode layer molded body side inward.

  Then, the laminated molded body which laminated | stacked the above molded objects was calcined at 1000 degreeC for 3 hours. Thereafter, the slurry for forming the first intermediate layer formed body was applied to the upper surface of the solid electrolyte calcined body by a screen printing method and dried to form the first intermediate layer formed body.

Subsequently, the LaCrO ₃ powder having an average particle diameter of 0.7 [mu] m, and NiO powder, and MgO powder were prepared and organic binder, an interconnector layer slurry obtained by mixing the solvent. The slurry for the inner layer molded article, relative LaCrO ₃ powder 100 parts by weight, and NiO powder, an inner layer molded body slurry MgO powder were added respectively 5 parts by weight, as for the outer layer forming member, LaCrO ₃ powder An outer layer molded body slurry was prepared by adding 2 parts by weight of NiO powder and MgO powder to 100 parts by weight, respectively.

  A raw material composed of Ni and YSZ was mixed and dried, and an organic binder and a solvent were mixed to prepare a second intermediate layer slurry. The adjusted slurry for the second intermediate layer is applied to the portion of the support where the fuel electrode layer (and the solid electrolyte layer) is not formed (the portion where the support is exposed), and the second intermediate layer formed body is laminated, The interconnector layer slurry was applied onto the second intermediate layer molded body.

  That is, first, a slurry for an inner layer molded body containing a large amount of NiO powder and MgO powder is applied and dried to form an inner layer molded body, and then an outer layer molding containing less NiO powder and MgO powder is formed on the inner layer molded body. The body slurry was applied and dried to form an outer layer molded body, and an interconnector layer molded body was formed on the second intermediate layer molded body.

  Subsequently, the above-mentioned laminated molded body was subjected to binder removal treatment and co-fired at 1450 ° C. for 2 hours in the air.

Next, a mixed liquid composed of La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ powder having an average particle diameter of 2 μm and isopropyl alcohol is prepared, and the surface of the first intermediate layer on the upper surface of the solid electrolyte Was spray-coated to form an oxygen electrode layer molded body and baked at 1100 ° C. for 4 hours to form an oxygen electrode layer, thereby producing the fuel cell shown in FIG.

  The size of the produced fuel cell is 25 mm × 200 mm, the thickness of the support (thickness between the flat surfaces n) is 2 mm, the thickness of the fuel electrode layer is 10 μm, the open porosity is 24%, the thickness of the solid electrolyte layer The thickness of the oxygen electrode layer was 50 μm, the open porosity was 40%, and the thickness of the interconnector layer was 30 μm.

  In the interconnector layer of the produced 10 fuel cells, the porosity of the inner layer and the outer layer was obtained with a scanning electron microscope (SEM) 300 times with an image analyzer, and the average values are shown in Table 1. Described. At the same time, the thickness was determined from the SEM photograph, and the average value is shown in Table 1. In () in the thickness column of Table 1, the ratio (%) to the total thickness of the interconnector layer is described.

  Hydrogen gas is flown inside 10 fuel cells, air is flowed outside, the conductive support and the fuel electrode layer are subjected to reduction treatment at 850 ° C. for 10 hours, and the interconnector layer is peeled off after the reduction treatment Was confirmed with a binocular microscope with a magnification of 20 ×, and even if one of the ten cells or a part of one cell was peeled, it was determined that there was peeling.

The gas barrier property by the interconnector layer was confirmed by a leak test of 10 fuel cells. In the leak test, a fuel cell in which a fuel gas passage on one side is sealed by a predetermined member is placed in water, and He gas pressurized to 3 kg / cm ² from the fuel gas passage on the other side of the fuel cell. For 60 seconds. The sample in which no bubbles were generated from the interconnector layer of 10 fuel cells was marked with ◯, the sample in which bubbles were generated from the interconnector layer of 2 or less fuel cells was marked with △, and the results were shown 1.

この表１から、インターコネクタ層全体が気孔率０．１％と緻密質である試料Ｎｏ．１では、インターコネクタ層の剥離が見られた。これに対して、外側層が内側層よりも多孔質である試料Ｎｏ．２〜８については、インターコネクタ層の剥離が見られなかった。さらに、外側層の厚みが、インターコネクタ層全体の厚みの１７〜５０％の厚みである場合には、ガスシール性能も良好となることがわかる。

From Table 1, it can be seen from Sample No. 1 that the entire interconnector layer is dense with a porosity of 0.1%. In 1, the peeling of the interconnector layer was observed. On the other hand, Sample No. in which the outer layer is more porous than the inner layer. About 2-8, peeling of the interconnector layer was not seen. Furthermore, when the thickness of an outer layer is 17 to 50% of the thickness of the whole interconnector layer, it turns out that gas-sealing performance becomes favorable.

1: Support body 2: Fuel gas passage 3: Fuel electrode layer (first electrode layer)
4: Solid electrolyte layer 6: Oxygen electrode layer (second electrode layer)
8: interconnector layer 8a: inner layer 8b: outer layer 11: cell stack device 18: fuel cell module 23: fuel cell device

The present invention, cell Le, cell Rusutakku device, a module and a module housing unit.

  In recent years, various fuel cell devices have been proposed in which a cell stack device formed by electrically connecting a plurality of solid oxide fuel cells in series is accommodated in a storage container as next-generation energy.

  The solid oxide fuel cell of such a fuel cell device has a pair of flat surfaces parallel to each other, a fuel gas passage for allowing fuel gas to flow inside, and contains Ni. A conductive support is provided. Then, a solid oxide formed by laminating a fuel electrode layer, a solid electrolyte layer, and an oxygen electrode layer in this order on a flat surface on one side of the conductive support and an interconnector layer on the flat surface on the other side. A fuel cell has been proposed (see, for example, Patent Document 1).

  Conventionally, in a solid oxide fuel cell, an interconnector layer made of a lanthanum chromite oxide is bonded to a conductive support or an intermediate support layer on the conductive support. It is constructed by joining both ends of a solid electrolyte layer made of a dense zirconia oxide formed so as to surround the periphery of the interconnector so that both ends of an interconnector layer made of a dense lanthanum chromite oxide overlap. Has been.

JP 2008-84716 A

  However, in a solid oxide fuel cell, the interconnector layer made of a lanthanum chromite oxide tends to expand when exposed to a reducing atmosphere and may be peeled off from a conductive support or the like.

The present invention, Rousset Le can suppress separation of the interconnector layer, Se Rusutakku apparatus, and an object thereof is to provide a module and the module housing device.

Cell Le of the present invention, a support, a first electrode layer containing Ni, are formed successively become by the solid electrolyte layer and a second electrode layer made of ceramic, the first electrode layer of the support is formed An interconnector layer made of a lanthanum chromite-based oxide that is electrically connected to the first electrode layer is provided in a portion that is not, and the interconnector layer includes an inner layer on the support side, and an inner layer of the inner layer. An outer layer provided on the outside, wherein the outer layer is more porous than the inner layer.

Also, cell Le of the present invention, the first electrode layer containing Ni as a support successively formed become by the solid electrolyte layer and a second electrode layer made of ceramic, the solid electrolyte layer of said support An interconnector layer made of a lanthanum chromite-based oxide that is electrically connected to the support is provided in a portion that is not formed, and the interconnector layer includes an inner layer on the support side, and an inner layer of the inner layer. An outer layer provided on the outside, wherein the outer layer is more porous than the inner layer.

Cell Rusutakku apparatus of the present invention, it becomes a plurality including the above cell Le, characterized by comprising electrically connecting the cell Le said plurality of.

Module of the present invention is characterized by comprising housing the above cell Rusutakku device storage container.

Module housing device of the invention, the above modules, the auxiliary device for operating the 該Mo joules and characterized by being accommodated in the exterior case.

Since the cell Le of the present invention, the support side of the interconnector layer (inner layer) is exposed to a reducing atmosphere, but the outer (outer layer) is exposed to an oxidizing atmosphere, the outer layer is more porous than the inner layer, Oxygen penetrates deeply from the outer layer surface in the thickness direction of the interconnector layer , and the reduction of the interconnector layer made of lanthanum chromite oxide can be suppressed, so that the reduction expansion of the entire interconnector layer can be suppressed and peeling from the support Can be suppressed.

1 shows a solid oxide fuel cell, where (a) is a cross-sectional view and (b) is a side view of (a) as viewed from the interconnector layer side. (A) is sectional drawing which expands and shows a part of interconnector layer, and its vicinity, (b) is a cross section which shows the solid oxide form fuel cell which does not form a 1st intermediate | middle layer in Fig.1 (a). FIG. It is a cross-sectional view showing a solid oxide fuel cell in which a fuel electrode layer is a support. An example of a cell stack apparatus is shown, (a) is a side view schematically showing the cell stack apparatus, (b) is an enlarged cross-sectional view showing a part of the cell stack apparatus surrounded by a broken line in (a). It is. 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.

1, a solid oxide fuel cell is an example of cell Le is indicative (hereinafter sometimes referred to as fuel cells), (a) is its horizontal sectional view, (b) is (a FIG. In both drawings, a part of each component of the fuel cell 10 is shown enlarged.

  The fuel battery cell 10 has a hollow flat plate type, and has a porous conductive support 1 containing Ni having a flat cross section and an elliptic cylinder shape as a whole. Inside the support 1, a plurality of fuel gas passages 2 are formed at appropriate intervals so as to penetrate in the length direction L of the fuel cell 10, and the fuel cell 10 is formed on the support 1 in various ways. It has the structure where the member of this was provided.

  As understood from the shape shown in FIG. 1, the 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. Yes. Both surfaces of the flat surface n are formed substantially parallel to each other, and are porous fuel electrode layers (first electrode layers) so as to cover one flat surface n (one main surface: lower surface) and both arc-shaped surfaces m. 3 is disposed, and a solid electrolyte layer 4 made of ceramics having gas barrier properties is disposed so as to cover the fuel electrode layer 3. The thickness of the solid electrolyte layer 4 is preferably 40 μm or less, 20 μm or less, and more preferably 15 μm or less from the viewpoint of improving power generation performance.

A porous oxygen electrode layer (second electrode layer) 6 is disposed on the surface of the solid electrolyte layer 4 so as to face the fuel electrode layer 3 with the first intermediate layer 9 interposed therebetween. The first intermediate layer 9 includes an oxygen electrode layer 6
Is formed on the solid electrolyte layer 4.

A lanthanum chromite system (LaCrO ₃ system) having gas barrier properties through the second intermediate layer 7 is formed on the other flat surface n (the other main surface: upper surface) of the support 1 on which the solid electrolyte layer 4 is not laminated. An interconnector 8 made of an oxide is formed.

  That is, the fuel electrode layer 3 and the solid electrolyte layer 4 are formed from one flat surface (one main surface: lower surface) to the other flat surface n (the other main surface: upper surface) via the arcuate surfaces m at both ends. In addition, both ends of the interconnector layer 8 are laminated and bonded to both ends of the solid electrolyte layer 4.

  That is, the solid electrolyte layer 4 having gas barrier properties and the interconnector layer 8 surround the support 1 so that fuel gas flowing through the inside does not leak to the outside. In other words, the solid electrolyte layer 4 and the interconnector layer 8 form an elliptic cylindrical body having gas barrier properties. The inside of the elliptic cylindrical body serves as a fuel gas flow path and is supplied to the fuel electrode layer 3. The fuel gas and the oxygen-containing gas supplied to the oxygen electrode layer 6 are blocked by an elliptic cylinder.

  Specifically, although not illustrated, the oxygen electrode layer 6 having a rectangular planar shape is formed except for the upper and lower ends of the support 1, while the interconnector layer 8 is formed as shown in FIG. As shown in FIG. 2, the support 1 is formed from the upper end to the lower end in the length direction L, and both end portions in the width direction W are joined to the surfaces of both end portions of the solid electrolyte layer 4.

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

  And in this embodiment, as shown to Fig.1 (a) and FIG.2 (a), the interconnector layer 8 is the outer side provided in the inner side layer 8a by the side of the support body 1, and this inner side layer 8a. And the outer layer 8b is more porous than the inner layer 8a.

  The inner layer 8a of the interconnector layer 8 has a porosity of 0.2% or less, and the outer layer 8b has a porosity of 0.3 to 2.0%. In particular, the porosity of the inner layer 8a is preferably less than 0.2%, and the porosity of the outer layer 8b is preferably 0.5 to 1.5%. The porosity can be determined with an image analysis device for a 300-fold photograph of a scanning electron microscope.

  The thickness of the interconnector layer 8 is desirably 10 to 60 μm, particularly 20 to 50 μm, and the thickness of the inner layer 8 a is 10 to 83% of the total thickness of the interconnector layer 8, particularly 50 to 83%. The thickness is desirable, and the thickness of the outer layer 8b is preferably 17 to 90% of the thickness of the entire interconnector layer 8, and particularly 17 to 50%. The inner layer 8a is preferably thicker than the outer layer 8b. Thereby, the gas barrier property and peeling by the interconnector layer 8 can be suppressed. The thickness of the inner layer 8a is preferably 3 μm or more, particularly 5 μm or more, and more preferably 10 μm or more.

  The interconnector layer 8 contains Mg and Ni, and the outer layer 8b has a smaller amount of Mg and Ni than the inner layer 8a. As a result, the outer layer 8b is less porous than the inner layer 8a, so the outer layer 8b is more porous than the inner layer 8a.

Although the boundary between the inner layer 8a and the outer layer 8b may not be clear, when Ni and Mg are detected by wavelength dispersion X-ray microanalyzer analysis (EPMA), the inner layer 8a of the interconnector layer 8 is Since the number of outer layers 8b is extremely small compared to the inner layer 8a, the boundary can be the boundary between the inner layer 8a and the outer layer 8b. The outer layer 8b may be formed using an outer layer molded body by adding a pore-forming agent for forming pores.

In the fuel cell configured as described above, the support 1 side (inner layer 8a) of the interconnector layer 8 is exposed to a reducing atmosphere and the outer side (outer layer 8b) is exposed to an oxidizing atmosphere. Even if 8a is reduced and expanded, the outer layer 8b is more porous than the inner layer 8a, so that oxygen penetrates deeply in the thickness direction of the interconnector layer 8 from the surface of the outer layer 8b and suppresses reduction of the LaCrO ₃ system oxide. Therefore, reduction expansion of the entire interconnector layer 8 can be suppressed, and peeling from the support 1 can be suppressed.

  FIG. 2B shows a form in the case where the second intermediate layer 7 is not provided. That is, in this embodiment, the interconnector layer 8 is directly bonded to the flat surface n of the support 1. Even with such a fuel cell, the same effect as described above can be obtained.

  FIG. 3 shows a case where the fuel electrode layer becomes the support 1, but even in this case, the same effect as that of FIG. 1 can be obtained. That is, in the embodiment of FIG. 1, the fuel electrode layer 3, the solid electrolyte layer 4, and the oxygen electrode layer 6 are laminated on the support 1, but the fuel electrode layer itself is used as the support 1 as shown in FIG. The body 1 may be provided with the solid electrolyte layer 4 and the oxygen electrode layer 6.

  Below, each member which comprises the fuel cell 10 of this embodiment is demonstrated. The conductive support 1 is required to be gas permeable in order to allow fuel gas to permeate to the fuel electrode layer 3 and to be conductive in order to collect current via the interconnector layer 8. From, for example, Ni and / or NiO and an inorganic oxide such as a specific rare earth oxide.

The specific rare earth oxide is used to make the thermal expansion coefficient of the support 1 close to the thermal expansion coefficient of the solid electrolyte layer 4, and is Y, Lu, Yb, Tm, Er, Ho, Dy, Gd. Rare earth oxides containing at least one element selected from the group consisting of Sm, 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 that the good conductivity of the support 1 is maintained and the thermal expansion coefficient is approximated to that of the solid electrolyte layer 4. It is preferably present in a volume ratio of 65:35. The support 1 may contain other metal components and oxide components as long as required characteristics are not impaired.

  Further, since the support 1 is required to have fuel gas permeability, it is porous and usually has an open porosity of 25% or more, particularly 30% or more, considering the support strength. It is preferable to be in the range of 35% or less, particularly 32% or less. Further, the conductivity of the 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 support 1 (the length of the support 1 in the width direction W) is, for example, 15 to 35 mm, and the length of the arcuate surface m (the length of the arc) is 2 to 8 mm. Yes, the thickness of the support 1 (thickness between the flat surfaces n) is 1.5 to 5 mm. The length of the support 1 is, for example, 100 to 300 mm.

The fuel electrode layer 3 causes an electrode reaction, and can be formed of a well-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 oxygen electrode layer 6, for example, the fuel electrode layer only on the flat surface n on the lower side of the support 1 on which the oxygen electrode layer 6 is provided. 3 may be formed. That is, the fuel electrode layer 3 is provided only on the lower flat surface n of the support 1, the solid electrolyte layer 4 is formed on the surface of the fuel electrode layer 3, the both arcuate surfaces m of the support 1 and the fuel electrode layer 3 are formed. It may have a structure formed on the flat surface n on the upper side of the support 1 that is not.

The solid electrolyte layer 4 is preferably made of a 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. The solid electrolyte layer 4 is not limited to ceramics made of partially stabilized or stabilized ZrO _2, and may of course be a conventionally known, for example, lanthanum galade based solid electrolyte layer. .

  The solid electrolyte layer 4 and the oxygen electrode layer 6 are strongly bonded to each other between the solid electrolyte layer 4 and the oxygen electrode layer 6 described later, and the components of the solid electrolyte layer 4 react with the components of the oxygen electrode layer 6. Thus, the first intermediate layer 9 is formed for the purpose of suppressing the formation of a reaction layer having a high electrical resistance.

The first intermediate layer 9 is made of a CeO2-based sintered body containing a rare earth element other than Ce. For example, (CeO ₂ ) _1-x (REO _1.5 ) _x (where 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 oxygen electrode layer 6 is preferably formed of a conductive ceramic made of a so-called ABO ₃ type perovskite oxide. Such perovskite oxides include La-containing transition metal perovskite oxides, particularly at least one of LaMnO ₃ oxides, LaFeO ₃ oxides, and LaCoO ₃ oxides in which Sr and La coexist at the A site. LaCoO ₃ oxides are particularly preferable from the viewpoint of high electrical conductivity at an operating temperature of about 600 to 1000 ° C. In the perovskite oxide, Fe and Mn may exist together with Co at the B site.

  Further, the oxygen electrode layer 6 needs to have gas permeability. Therefore, the conductive ceramic (perovskite oxide) forming the oxygen 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 oxygen electrode layer 6 is preferably 30 to 100 μm from the viewpoint of current collection.

The interconnector layer 8 is made of conductive ceramics. 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, conductive ceramics such as lanthanum chromite perovskite oxide (LaCrO ₃ oxide) are used as conductive ceramics having reduction resistance and oxidation resistance. For the purpose of bringing the coefficient of thermal expansion close to that of the electrolyte layer 4, LaCrO ₃ and MgO, NiO, or LaCrO ₃ oxide in which MgO and NiO are dissolved are used. In addition, MgO and NiO may be dissolved in LaCrO ₃ in some cases.

  Further, the thickness of the interconnector layer 8 is preferably 10 to 60 μm from the viewpoints of gas leakage prevention and electrical resistance. Within this range, gas leakage can be prevented and electrical resistance can be reduced.

  Further, a second intermediate layer 7 can be formed between the support 1 and the interconnector layer 8 in order to reduce the difference in thermal expansion coefficient between the interconnector layer 8 and the support 1. .

The second intermediate layer 7 can have a composition similar to that of the fuel electrode layer 3. For example, it can be formed from at least one of rare earth oxide, ZrO _{2 in which} a rare earth element is dissolved, and CeO ₂ in which a rare earth element is dissolved, and Ni and / or NiO. More specifically, for example, a composition composed of Y ₂ O ₃ and Ni and / or NiO, a composition composed of ZrO ₂ (YSZ) in which Y is solid-solved and Ni and / or NiO, Y, Sm, Gd and the like are solid. It can be formed from a composition comprising dissolved CeO ₂ and Ni and / or NiO. The volume ratio of ZrO ₂ (CeO ₂ ) in which rare earth oxide or rare earth element is dissolved and Ni and / or NiO is preferably in the range of 40:60 to 60:40.

An example of a method for producing 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 support molded body is prepared and dried. In addition, you may use the calcined body which calcined the support body molded object at 900-1000 degreeC for 2 to 6 hours as a support body molded object.

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

  Then, a slurry of a ZrO2 powder in which a rare earth element is dissolved and toluene, a binder powder, a commercially available dispersant, and the like are added to form a slurry by a method such as a doctor blade to produce a sheet-shaped solid electrolyte layer molded body To do.

  The fuel electrode layer slurry is applied onto the obtained sheet-shaped solid electrolyte layer molded body and dried to form a fuel electrode layer molded body, thereby forming a sheet-shaped laminated molded body. The surface on the fuel electrode layer molded body side of the sheet-shaped laminated molded body in which the fuel electrode layer molded body and the solid electrolyte layer molded body are laminated is laminated on a conductive support molded body to form a laminated molded body. Calcination at ~ 1200 ° C for 2-6 hours.

Subsequently, an interconnector layer material (for example, LaCrO ₃ -based oxide powder + MgO powder + NiO powder), an organic binder and a solvent are mixed to produce a slurry having a large amount of NiO and MgO and a slurry having a small amount of NiO and MgO (interlayer). Connector layer slurry).

Subsequently, a molded body of the second intermediate layer 7 located between the support 1 and the interconnector layer 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, an organic binder or the like is added to adjust the slurry for the second intermediate layer, A second intermediate layer molded body is formed by applying the solid molded body on the support molded body between both end portions of the solid electrolyte layer molded body.

Subsequently, a first intermediate layer 9 disposed between the solid electrolyte layer 4 and the oxygen 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 adjust the raw material powder for the first intermediate layer formed body. Toluene is added to the raw material powder as a solvent to prepare a first intermediate layer slurry, and this slurry is applied onto the solid electrolyte layer formed body to form a first intermediate layer formed body.

  Thereafter, the interconnector layer slurry is applied to the upper surface of the second intermediate layer molded body so that both ends of the interconnector layer molded body are laminated on both ends of the solid electrolyte molded body (calcined body). A laminated molded body is produced. At this time, first, an interconnector layer slurry containing a large amount of NiO and MgO is applied and dried to form an inner layer molded body, and then an interconnector layer slurry containing less NiO and MgO is applied onto the inner layer molded body. And drying to form an outer layer molded body, and an interconnector layer molded body is formed.

  In addition, an interconnector layer sheet in which an inner layer molded body and an outer layer molded body are laminated is prepared, and both end portions of the interconnector layer sheet are laminated on both end portions of the solid electrolyte molded body. In addition, an interconnector layer sheet may be laminated on the upper surface of the second intermediate layer molded body so that the inner layer molded body abuts on the upper surface of the second intermediate layer molded body.

  The interconnector layer sheet is formed by applying an interconnector layer slurry containing a large amount of NiO and MgO, and drying to form an inner layer molded body. Then, the interconnector layer slurry containing less Ni and Mg is formed on the inner layer molded body. And dried to form an outer layer molded body. Moreover, the sheet | seat for interconnector layers is producible also by producing an inner layer molded object and an outer layer molded object separately, respectively, and laminating | stacking these.

  Next, the above-mentioned laminated molded body is subjected to binder removal treatment, and is simultaneously sintered (co-fired) in an oxygen-containing atmosphere at 1400 to 1500 ° C., particularly at 1425 to 1475 ° C. for 2 to 6 hours.

  Since the outer layer molded body with less NiO and MgO has lower sinterability than the inner layer molded body with more NiO and MgO, the outer layer 8b becomes more porous than the inner layer 8a after simultaneous firing.

Further, a slurry containing an oxygen electrode layer material (for example, LaCoO ₃ -based oxide powder), a solvent and a pore former is applied onto the first intermediate layer by dipping or the like, and the temperature is 1000 to 1300 ° C. for 2 to 6 hours. By baking, the fuel cell 10 of this embodiment having the structure shown in FIG. 1 can be manufactured.

  FIG. 4 shows an example of a cell stack device configured by electrically connecting a plurality of the above-described fuel cells 10 in series via a current collecting member 13, and (a) shows a cell stack. The side view which shows the stack | stuck apparatus 11 roughly, (b) is a partial expanded sectional view of the cell stack apparatus 11 of (a), and has extracted and shown the part enclosed with the broken line shown in (a). . In addition, in (b), the part corresponding to the part surrounded by the broken line shown in (a) is indicated by an arrow for the sake of clarity, and in the fuel cell 10 shown in (b), the above-described first Some members such as the intermediate layer 9 are omitted.

  In the cell stack device 11, each fuel battery cell 10 is arranged via a current collecting member 13 to form a cell stack 12, and the lower end portion of each fuel battery cell 10 is the fuel battery cell 10. Is fixed to a gas tank 16 for supplying fuel gas with an adhesive such as a glass sealing material. In addition, the cell stack 12 is sandwiched from both ends of the fuel cell 10 in the arrangement direction by the elastically deformable conductive member 14 whose lower end is fixed to the gas tank 16.

  Further, in the conductive member 14 shown in FIG. 4, a current for drawing out a current generated by power generation of the cell stack 12 (fuel cell 10) in a shape extending outward along the arrangement direction of the fuel cells 10. A drawer portion 15 is provided.

  The lower end portion of the fuel cell 10 is inserted into an opening formed on the upper surface of the gas tank 16, and is fixed by an adhesive such as a glass seal material.

  FIG. 5 is an external perspective view showing an example of a fuel cell module 18 in which the cell stack device 11 is stored in a storage container. The cell stack device 11 shown in FIG. It is configured to store.

  In order to obtain the fuel gas used in the fuel cell 10, a reformer 20 for reforming raw fuel such as natural gas or kerosene to generate fuel gas is disposed above the cell stack 12. ing. 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 fuel gas passage 2 provided inside the fuel cell 10 via the gas tank 16. .

  FIG. 5 shows a state in which a part (front and rear surfaces) of the storage container 19 is removed and the cell stack device 11 and the reformer 20 housed inside are taken out rearward. In the fuel cell module 18 shown in FIG. 5, the cell stack device 11 can be slid and stored in the storage container 19. The cell stack device 11 may include the reformer 20.

  Further, in FIG. 5, the oxygen-containing gas introduction member 22 provided inside the storage container 19 is disposed between a pair of cell stacks 12 juxtaposed to the gas tank 16, and the oxygen-containing gas flows into the flow of the fuel gas. 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 fuel gas passage 2 of the fuel cell 10 with the oxygen-containing gas and burning it on the upper end side of the fuel cell 10. The activation of the cell stack device 11 can be accelerated. Further, by burning the fuel gas and the oxygen-containing gas discharged from the gas passage 2 of the fuel battery cell 10 on the upper end side of the fuel battery cell 10, the fuel cell 10 is placed above the fuel battery cell 10 (cell stack 12). The arranged reformer 20 can be warmed. Thereby, the reforming reaction can be efficiently performed in the reformer 20.

  Further, in the fuel cell module 18 of the present embodiment, the cell stack device 11 using the above-described fuel cell 10 is housed in the housing container 19, so that the fuel has high power generation performance and improved long-term reliability. The battery module 18 can be obtained.

  6 is a perspective view showing an example of a fuel cell device in which the fuel cell module 18 shown in FIG. 5 and an auxiliary machine (not shown) for operating the cell stack device 11 are housed in an outer case. It is. In FIG. 6, a part of the configuration is omitted.

  A fuel cell device 23 shown in FIG. 6 has a module housing chamber in which an outer case made up of support columns 24 and an outer plate 25 is divided into upper and lower portions by a partition plate 26 and the upper side thereof stores the above-described fuel cell module 18. 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 power generation performance is high by having the fuel cell module 18 housed in the module storage chamber 27 with high power generation performance and improved reliability. The fuel cell device 23 having high reliability and improved reliability can be obtained.

  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. However, it is needless to say that a cylindrical solid oxide fuel cell may be used. Also, a so-called horizontal stripe fuel cell may be used. Furthermore, various intermediate layers may be formed between the members in accordance with the function.

Furthermore, the fuel cell in the above embodiment, the cell stack device has been described the fuel cell module and fuel cell device, the present invention is not limited thereto, by applying the steam and voltage cell Le vapor ( It can also be applied to an electrolysis cell (SOEC) that generates hydrogen and oxygen (O ₂ ) by electrolyzing (water), and an electrolysis module and electrolysis apparatus including the electrolysis cell.

First, a NiO powder having an average particle size of 0.5 μm and a Y ₂ O ₃ powder having an average particle size of 0.9 μm are mixed, and a clay prepared with an organic binder and a solvent is molded by an extrusion molding method and dried. Degreasing was performed to produce a conductive support molded body. The volume ratio of the support molded body was 48% by volume for NiO and 52% by volume for Y ₂ O ₃ .

Next, a slurry obtained by mixing an organic binder and a solvent with ZrO2 powder (solid electrolyte layer raw material powder) having a particle diameter of 0.8 μm by a microtrack method in which 8 mol% of Y ₂ O ₃ is solid-dissolved is obtained. The solid electrolyte layer sheet was prepared using the doctor blade method.

The slurry for forming the first intermediate layer formed body is composed of 90% by mole of CeO2 and 10% by mole of a rare earth element oxide (GdO _1.5 , SmO _1.5 ) as a solvent and isopropyl alcohol as a solvent. (IPA) is pulverized with a vibration mill or ball mill, calcined at 900 ° C. for 4 hours, pulverized again with a ball mill to adjust the degree of aggregation of ceramic particles, A binder and a solvent were added and mixed.

Next, a slurry for a fuel electrode layer is prepared by mixing a NiO powder having an average particle size of 0.5 μm, a ZrO2 powder in which Y ₂ O ₃ is dissolved, an organic binder, and a solvent, and a screen printing method is performed on the solid electrolyte layer sheet. Was applied and dried to form a fuel electrode layer molded body.

  A sheet-like laminated molded body in which the fuel electrode layer molded body was formed on the solid electrolyte layer sheet was laminated at a predetermined position of the support molded body with the surface on the fuel electrode layer molded body side inward.

  Then, the laminated molded body which laminated | stacked the above molded objects was calcined at 1000 degreeC for 3 hours. Thereafter, the slurry for forming the first intermediate layer formed body was applied to the upper surface of the solid electrolyte calcined body by a screen printing method and dried to form the first intermediate layer formed body.

Subsequently, the LaCrO ₃ powder having an average particle diameter of 0.7 [mu] m, and NiO powder, and MgO powder were prepared and organic binder, an interconnector layer slurry obtained by mixing the solvent. The slurry for the inner layer molded article, relative LaCrO ₃ powder 100 parts by weight, and NiO powder, an inner layer molded body slurry MgO powder were added respectively 5 parts by weight, as for the outer layer forming member, LaCrO ₃ powder An outer layer molded body slurry was prepared by adding 2 parts by weight of NiO powder and MgO powder to 100 parts by weight, respectively.

  A raw material composed of Ni and YSZ was mixed and dried, and an organic binder and a solvent were mixed to prepare a second intermediate layer slurry. The adjusted slurry for the second intermediate layer is applied to the portion of the support where the fuel electrode layer (and the solid electrolyte layer) is not formed (the portion where the support is exposed), and the second intermediate layer formed body is laminated, The interconnector layer slurry was applied onto the second intermediate layer molded body.

  That is, first, a slurry for an inner layer molded body containing a large amount of NiO powder and MgO powder is applied and dried to form an inner layer molded body, and then an outer layer molding containing less NiO powder and MgO powder is formed on the inner layer molded body. The body slurry was applied and dried to form an outer layer molded body, and an interconnector layer molded body was formed on the second intermediate layer molded body.

  Subsequently, the above-mentioned laminated molded body was subjected to binder removal treatment and co-fired at 1450 ° C. for 2 hours in the air.

Next, a mixed liquid composed of La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ powder having an average particle diameter of 2 μm and isopropyl alcohol is prepared, and the surface of the first intermediate layer on the upper surface of the solid electrolyte Was spray-coated to form an oxygen electrode layer molded body and baked at 1100 ° C. for 4 hours to form an oxygen electrode layer, thereby producing the fuel cell shown in FIG.

  The size of the produced fuel cell is 25 mm × 200 mm, the thickness of the support (thickness between the flat surfaces n) is 2 mm, the thickness of the fuel electrode layer is 10 μm, the open porosity is 24%, the thickness of the solid electrolyte layer The thickness of the oxygen electrode layer was 50 μm, the open porosity was 40%, and the thickness of the interconnector layer was 30 μm.

  In the interconnector layer of the produced 10 fuel cells, the porosity of the inner layer and the outer layer was obtained with a scanning electron microscope (SEM) 300 times with an image analyzer, and the average values are shown in Table 1. Described. At the same time, the thickness was determined from the SEM photograph, and the average value is shown in Table 1. In () in the thickness column of Table 1, the ratio (%) to the total thickness of the interconnector layer is described.

  Hydrogen gas is flown inside 10 fuel cells, air is flowed outside, the conductive support and the fuel electrode layer are subjected to reduction treatment at 850 ° C. for 10 hours, and the interconnector layer is peeled off after the reduction treatment Was confirmed with a binocular microscope with a magnification of 20 ×, and even if one of the ten cells or a part of one cell was peeled, it was determined that there was peeling.

The gas barrier property by the interconnector layer was confirmed by a leak test of 10 fuel cells. In the leak test, a fuel cell in which a fuel gas passage on one side is sealed by a predetermined member is placed in water, and He gas pressurized to 3 kg / cm ² from the fuel gas passage on the other side of the fuel cell. For 60 seconds. The sample in which no bubbles were generated from the interconnector layer of 10 fuel cells was marked with ◯, the sample in which bubbles were generated from the interconnector layer of 2 or less fuel cells was marked with △, and the results were shown 1.

この表１から、インターコネクタ層全体が気孔率０．１％と緻密質である試料Ｎｏ．１では、インターコネクタ層の剥離が見られた。これに対して、外側層が内側層よりも多孔質である試料Ｎｏ．２〜８については、インターコネクタ層の剥離が見られなかった。さらに、外側層の厚みが、インターコネクタ層全体の厚みの１７〜５０％の厚みである場合には、ガスシール性能も良好となることがわかる。

From Table 1, it can be seen from Sample No. 1 that the entire interconnector layer is dense with a porosity of 0.1%. In 1, the peeling of the interconnector layer was observed. On the other hand, Sample No. in which the outer layer is more porous than the inner layer. About 2-8, peeling of the interconnector layer was not seen. Furthermore, when the thickness of an outer layer is 17 to 50% of the thickness of the whole interconnector layer, it turns out that gas-sealing performance becomes favorable.

1: Support body 2: Fuel gas passage 3: Fuel electrode layer (first electrode layer)
4: Solid electrolyte layer 6: Oxygen electrode layer (second electrode layer)
8: interconnector layer 8a: inner layer 8b: outer layer 11: cell stack device 18: fuel cell module 23: fuel cell device

Claims (6)

  A first electrode layer containing Ni, a solid electrolyte layer made of ceramic, and a second electrode layer are sequentially formed on a support, and the first electrode layer of the support is not formed on the portion where the first electrode layer is not formed. An interconnector layer made of a lanthanum chromite oxide electrically connected to one electrode layer is provided, and the interconnector layer includes an inner layer on the support side and an outer layer provided outside the inner layer. The electrolytic cell is characterized in that the outer layer is more porous than the inner layer.   A solid electrolyte layer made of ceramic and a second electrode layer are sequentially formed on a first electrode layer containing Ni to be a support, and the support is formed on a portion of the support where the solid electrolyte layer is not formed. An interconnector layer made of a lanthanum chromite oxide that is electrically connected to the body, and the interconnector layer includes an inner layer on the support side and an outer layer provided outside the inner layer. An electrolytic cell comprising: the outer layer being more porous than the inner layer.   The electrolysis cell according to claim 1 or 2, wherein the porosity of the inner layer of the interconnector layer is 0.2% or less, and the porosity of the outer layer is 0.3 to 2.0%. .   An electrolysis cell stack device comprising a plurality of electrolysis cells according to any one of claims 1 to 3, wherein the electrolysis cells are electrically connected.   An electrolytic module comprising the electrolytic cell stack device according to claim 4 housed in a housing container.   6. An electrolysis apparatus comprising the electrolysis module according to claim 5 and an auxiliary machine for operating the electrolysis module housed in an outer case.

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