JP6591877B2 - Cell, cell stack device, module, and module housing device - Google Patents

Description

  The present invention relates to a cell, a cell stack device, a module, and a module housing device.

  In recent years, fuel cells that can obtain electric power using a fuel gas (hydrogen-containing gas) and an oxygen-containing gas (usually air) have been developed as next-generation energy. A fuel cell (hereinafter referred to as a cell) has a structure in which a solid electrolyte layer is sandwiched between a fuel electrode layer and an air electrode layer. The cell generates power by flowing fuel gas through the fuel electrode layer and oxygen-containing gas through the air electrode layer and heating the cell (see, for example, Patent Document 1).

  As an example of the cell, in the cell described in Patent Document 1, a power generation element portion in which a solid electrolyte layer is sandwiched between a fuel electrode layer and an air electrode layer is provided on a support. The support has a pair of surfaces and a pair of side surfaces, contains Ni, and has a flat plate shape. A gas flow path is provided inside the support, and fuel gas flows through this gas flow path. The fuel electrode layer is provided on the support so as to cover the first surface and both side surfaces of the support. The solid electrolyte layer covers the fuel electrode layer and is provided from the first surface to the pair of side surfaces of the support. The air electrode layer is provided on the solid electrolyte layer so as to face the fuel electrode layer. The interconnector layer is provided on the second surface, and has a function of taking out the current generated by the power generation element unit. The interconnector layer is preferably dense in order to suppress leakage of the fuel gas flowing through the gas flow path provided in the support and the oxygen-containing gas flowing through the outside of the support. Patent Document 1 discloses a solid oxide fuel cell that can suppress deformation when the interconnector layer is exposed to a reducing atmosphere.

JP 2013-97978 A

  However, when the oxygen-containing gas flowing outside the cell flows into the gas flow path inside the support, Ni contained in the support oxidizes and expands, and stress is applied to the interconnector layer in contact with the support. Cracks will occur in the part.

  Accordingly, an object of the present invention is to provide a cell, a cell stack device, a module, and a module housing device that can suppress the occurrence of cracks in the interconnector layer.

  The cell of the present invention is columnar, has a pair of opposing surfaces, has a gas flow passage for allowing fuel gas to flow along the longitudinal direction therein, a Ni-containing support, and a support A first electrode layer provided on the first surface of the pair of surfaces, a solid electrolyte layer provided on the first electrode layer, a second electrode layer provided on the solid electrolyte layer, and a support An interconnector layer provided on the second surface of the pair of main surfaces of the body is provided. The interconnector layer is located on the most support side and has a first layer having a higher porosity than other portions of the interconnector layer.

  A cell stack device according to the present invention includes a cell stack formed by arranging a plurality of the cells.

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

  In addition, a module housing apparatus of the present invention includes the above-described module and an auxiliary device for operating the module in an exterior case.

  According to the cell of the present invention, generation of cracks in the interconnector layer can be suppressed. Even in a cell stack device, a module, and a module storage device using such a cell, occurrence of cracks in the interconnector layer can be suppressed.

The cell is shown, (a) is a cross-sectional view, (b) is a side view seen from the interconnector layer side. It is sectional drawing in the thickness direction of a part of interconnector layer. FIG. 3 is an enlarged view of the vicinity of pores in the cross-sectional view of FIG. 2. The cell stack apparatus is shown, (a) is a side view, (b) is a cross-sectional view showing a part of (a). It is an external appearance perspective view which shows an example of a fuel cell module. It is a perspective view which omits and shows a part of fuel cell device.

  A cell, a cell stack device, a module, and a module housing device will be described with reference to FIGS. In addition, the same code | symbol shall be used about the same structure. In the following, description will be made using an example of a solid oxide type hollow plate cell as a cell.

(Cell structure)
1A and 1B show one embodiment of a cell. FIG. 1A is a cross-sectional view of the cell, and FIG. In both drawings, each configuration of the cell 1 is partially enlarged. FIG. 2 is a cross-sectional view in the thickness direction T of a part of the interconnector layer 6. The longitudinal direction is L, the transverse direction is W, and the thickness direction is T.

  The cell 1 includes a support 2, a fuel electrode layer 3, a solid electrolyte layer 4, an air electrode layer 5, and an interconnector layer 6.

  The support body 2 has an elliptical shape with a flat cross section, and has an elliptical column shape as a whole. The support 2 is a porous body. As shown in FIG. 1, the support body 2 has a flat plate shape having a pair of first and second surfaces n1 and n2 and a pair of side surfaces m. In the example shown in FIG. 1, the pair of first surface n1 and second surface n2 face each other. In the example shown in FIG. 1, each of the pair of side surfaces m is an arcuate surface. The pair of side surfaces m may be flat surfaces.

  Further, a plurality of gas flow paths 2 a penetrate through the support body 2 in the longitudinal direction L at appropriate intervals. Various members described later surround the outer periphery of the support 2.

  The fuel electrode layer 3 is provided on the first surface n1 of the support 2 as shown in FIG. In the example shown in FIG. 1, the fuel electrode layer 3 is provided on the support 2 so as to cover the first surface n1 of the support 2 and the side surfaces m on both sides. Further, since the fuel electrode layer 3 only needs to be provided at a position facing the air electrode layer 5 with the solid electrolyte layer 4 interposed therebetween, for example, the fuel electrode layer 3 does not extend to the second surface n2 and the side surface m, It may be provided only on the first surface n1. The fuel electrode layer 3 is a porous body.

  As shown in FIG. 1, the solid electrolyte layer 4 covers the fuel electrode layer 3, and is provided from the first surface n <b> 1 of the support 2 to a pair of side surfaces m.

  As shown in FIG. 1, the air electrode layer 5 is provided on the solid electrolyte layer 4 so as to face the fuel electrode layer 3. In the example shown in FIG. 1, it is disposed on the first surface n <b> 1 of the support 2 and outside the solid electrolyte layer 4. The air electrode layer 5 is a porous body.

  The interconnector layer 6 is provided on the second surface n2 of the support 2.

  In the cell 1 described above, a portion where the fuel electrode layer 3, the solid electrolyte layer 4, and the air electrode layer 5 are stacked functions as a power generation element portion. In order to generate electric power, an oxygen-containing gas such as air is allowed to flow outside the air electrode layer 5, and a fuel gas (hydrogen-containing gas) is allowed to flow in the gas flow path 2 a in the support 2, so that fuel is supplied to the fuel electrode layer 3. Gas is supplied and the fuel electrode layer 3 is heated to a predetermined operating temperature. The current generated by the power generation is collected at the interconnector layer 6.

  In the example shown in FIG. 1, the fuel electrode layer 3 and the solid electrolyte layer 4 extend from the first surface n1 to the part of the second surface n2 via the side surfaces m at both ends, and both end portions of the solid electrolyte layer 4 Both end portions of the interconnector layer 6 are laminated and bonded to each other. Thereby, the support body 2 is surrounded by the solid electrolyte layer 4 and the interconnector layer 6, and the fuel gas flowing through the inside can be prevented from leaking to the outside.

  In the example shown in FIG. 1, the interconnector layer 6 having a rectangular planar shape is disposed so as to cover from the upper end to the lower end in the longitudinal direction L of the support body 2, and the left and right ends of the interconnector layer 6 are solid. The electrolyte layer 4 is joined to be overlapped on both ends.

(Description of each member of the cell)
The support 2 is required to be gas permeable in order to allow the fuel gas to permeate to the fuel electrode layer 3 and to be conductive in order to be connected to the interconnector layer 6 and collect current. Therefore, as the support 2, conductive ceramics, cermet, or the like can be used. The conductivity is preferably 300 S / cm or more, and particularly preferably 440 S / cm or more. In order to provide gas permeability, the open porosity is preferably 25% or more.

  The support 2 contains Ni. Ni here means metallic nickel. That is, Ni is distinguished from NiO (nickel oxide) described later.

In this example, the support 2 has Ni, NiO, and a specific rare earth oxide. The specific rare earth oxide is used to bring the thermal expansion coefficient of the support 2 close to the thermal expansion coefficient of the solid electrolyte layer 4, and Y, Lu, Yb, Tm, Er, Ho, Dy, Gd, A rare earth oxide containing at least one element selected from the group consisting of Sm and Pr is used. 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 , and Pr ₂ O ₃ can be exemplified. Moreover, from the point that there is almost no solid solution and reaction with Ni and NiO, the thermal expansion coefficient is the same as that of the solid electrolyte layer 4, and it is inexpensive, it is from at least one of Y ₂ O ₃ and Yb ₂ O _3. It ’s good. In the present embodiment, Ni and NiO: rare earth oxide = 35: 65 to 65:65 in that the good conductivity of the support 2 is maintained and the thermal expansion coefficient is approximated to that of the solid electrolyte layer 4. It exists in a volume ratio of 35. Further, when the support 2 contains both Ni and NiO, the ratio of Ni and NiO is not particularly limited, but Ni always exists. The support 2 may contain other metal components and oxide components as long as required characteristics are not impaired.

  Furthermore, according to this embodiment, the length of the first surface n1 and the second surface n2 of the support 2 in the short direction W is 15 to 60 mm, and the length of the side surface m (the length of the arc) is 2 to 2. The thickness between the first surface n1 and the second surface n2 of the support 2 is 1.5 to 5 mm, and the length in the longitudinal direction L of the support 2 is 10 to 50 cm.

The fuel electrode layer 3 causes an electrode reaction. In the present embodiment, the fuel electrode layer 3 is made of porous conductive ceramics. For example, a material made of ZrO ₂ and Ni and / or NiO in which a rare earth oxide is dissolved, or a material made of CeO ₂ and Ni and / or NiO in which another rare earth oxide is dissolved is cited. Incidentally, the rare earth oxides can be used those exemplified in the support 2, for example, _Y 2 _{O 3} and the like materials consisting of _ZrO 2 and (YSZ) and Ni and / or NiO, which solid solution. In this embodiment, the content of ZrO ₂ in which the rare earth oxide in the fuel electrode layer 3 is dissolved or CeO ₂ in which the other rare earth oxide is dissolved is in the range of 35 to 65% by volume, Ni and / or Or content of NiO is 65-35 volume%. Further, the open porosity of the fuel electrode layer 3 is, for example, 15% or more, particularly 20 to 40%, and its thickness is 1 to 30 μm.

The solid electrolyte layer 4 functions as a solid electrolyte layer 4 that bridges ions between the fuel electrode layer 3 and the air electrode layer 5, and at the same time, prevents leakage of fuel gas and oxygen-containing gas. It is necessary to have gas barrier properties. In this embodiment, ceramic (solid oxide) made of partially stabilized or stabilized ZrO ₂ containing 3 to 15 mol% of an oxide of rare earth elements such as Y, Sc, and Yb is used. Y is used as the rare earth element because it is inexpensive. The solid electrolyte layer 4 may be made of, for example, a LaGaO ₃ -based material, and may be made of other materials as long as it has the above characteristics. In the present embodiment, the thickness of the solid electrolyte layer 4 is 10 to 40 μm.

The air electrode layer 5 is not particularly limited as long as it is generally used. For example, the air electrode layer 5 can be formed of a conductive ceramic made of a so-called ABO ₃ type perovskite oxide. Specifically, LaSrCoFeO ₃ , LaSrMnO ₃ , LaSrCoO ₃ or the like can be used. The air electrode layer 5 is required to have gas permeability and preferably has an open porosity of 20% or more, particularly 30 to 50%.

For the interconnector layer 6, a lanthanum chromite perovskite oxide (LaCrO ₃ oxide) or a lanthanum strontium titanium perovskite oxide (LaSrTiO ₃ oxide) is preferably used. These materials have conductivity and are not easily reduced or oxidized even when they come into contact with fuel gas (hydrogen-containing gas) and oxygen-containing gas (air or the like).

  Further, the interconnector layer 6 is preferably dense in order to suppress leakage of the fuel gas flowing through the gas flow path 2 a provided in the support 2 and the oxygen-containing gas flowing outside the support 2.

  By the way, an oxygen-containing gas flowing outside the cell 1 may flow into the gas flow path 2 a inside the support 2. For example, when the supply amount of the fuel gas is reduced or when the supply of the fuel gas is stopped. In these cases, since Ni contained in the support 2 is oxidized and expanded, stress is applied to the interconnector layer 6 in contact with the support 2, and cracks are generated in this portion.

Therefore, as shown in FIG. 2, the interconnector layer 6 has a first layer 6a, and the first layer 6a is located closest to the support 2 and has a higher porosity than the other portions. ing. The “other part” here means a part of the interconnector layer 6 other than the first layer 6a. With this configuration, since a relatively large number of pores are present in the first layer 6a, stress concentration on the interconnector layer 6 due to the oxidative expansion of Ni contained in the support 2 can be reduced. Therefore, the occurrence of cracks in the interconnector layer 6 can be suppressed.

  Further, the interconnector layer 6 contains Ni, and as shown in the example shown in FIG. 2, the interconnector layer 6 has the second layer 6b at a position farther from the support 2 than the first layer 6a. The second layer 6b preferably has a lower porosity than the other portions. The “other part” here means a part other than the second layer 6 b in the interconnector layer 6. When lanthanum chromite is used as the material of the interconnector layer 6, the interconnector layer 6 expands in a reducing atmosphere. In addition, when the interconnector layer 6 contains Ni, it exists as NiO in an oxidizing atmosphere, and NiO is reduced and exists as Ni in a reducing atmosphere. Therefore, while lanthanum chromite is reduced and expanded in a reducing atmosphere, NiO is reduced and contracted, so that the volume expansion of the entire interconnector layer 6 can be suppressed. Therefore, damage to the interconnector layer 6 can be suppressed. On the other hand, when the oxygen-containing gas flowing on the outer surface penetrates into the interconnector layer 6, Ni in the interconnector layer 6 is oxidized and the volume expands, and the entire interconnector layer 6 easily expands. Therefore, the presence of the second layer 6b having a lower porosity than the other portions at a position farther from the support 2 than the first layer 6a can suppress the intrusion of the oxygen-containing gas by the second layer 6b. . Therefore, in the interconnector layer 6, in the region on the support 2 side from the second layer 6b, the volume expansion of Ni can be suppressed, so that damage to the interconnector layer 6 can be suppressed.

  The content of Ni in the interconnector layer 6 is preferably 5 to 15% by volume, for example.

  Further, the porosity of the first layer 6a may be 2 to 10%. When the porosity of the first layer 6a is 2% or more, the stress concentration on the first layer 6a can be further relaxed. On the other hand, when the porosity is 10% or less, the probability that open pores are present at the interface between the interconnector layer 6 and the support 2 can be suppressed, and therefore the area where the support 2 and the interconnector layer 6 are joined. Can be increased. Accordingly, the bonding strength can be sufficiently maintained, and peeling of the interconnector layer 6 can be suppressed. More preferably, the porosity of the first layer 6a is 3 to 9%.

  The porosity of the second layer 6b is preferably 0.2% or less. In this case, it is possible to further suppress the oxygen-containing gas from entering the inside in the interconnector layer 6.

  Further, the interconnector layer 6 further includes a third layer 6c between the first layer 6a and the second layer 6b, and the porosity of the third layer 6c is lower than that of the first layer 6a. It may be higher than the layer 6b. According to this configuration, the third layer 6c having a lower porosity than the first layer 6a can further prevent the oxygen-containing gas flowing on the outer surface of the interconnector layer 6 from entering the interconnector layer 6. In addition, since the porosity of the third layer 6c is intermediate between the first layer 6a and the second layer 6b, when the first layer 6a is deformed by the stress from the support 2, the porosity is low and is difficult to deform. It is possible to suppress the stress from being transmitted to the two layers 6b. Therefore, it is possible to suppress the occurrence of damage inside the interconnector layer 6.

  Further, as in the example shown in FIG. 3, the thickness (Tc) of the third layer 6c is preferably larger than the thickness (Ta) of the first layer 6a and the thickness (Tb) of the second layer 6b. With this configuration, the above-described effect of preventing the oxygen-containing gas from entering the interconnector layer 6 can be improved. Moreover, the damage suppression effect inside the interconnector layer 6 can be further improved.

  In addition, as shown in FIG. 3, the interconnector layer 6 preferably contains Ni, and at least a part of the inner walls of the pores in the interconnector layer 6 is preferably made of Ni. According to this configuration, when the oxygen-containing gas enters the interconnector layer 6 or when oxygen ions enter the interconnector layer 6 through the grain boundary, Ni inside the interconnector layer 6 is oxidized and expanded. However, the pores can absorb the volume expansion of Ni. Therefore, it can suppress that the volume as the interconnector layer 6 whole expands rapidly. Therefore, damage inside the interconnector layer 6 can be suppressed.

(Measuring method)
First, a method for measuring the porosity of the first layer 6a will be described. The area occupation ratio of the pores in the cross section of the first layer 6a is calculated, and is used as the porosity. Specifically, SEM (Scanning Electron M) having a cross-sectional magnification of 1000 times in the thickness direction T of the interconnector layer 6.
image, scanning electron microscope). Calculate the cross-sectional area of the entire first layer 6a in the SEM image, calculate the total area of the pores of the first layer 6a, calculate "total area of the pores / cross-sectional area of the entire first layer 6a", This value is defined as the area occupation ratio of the pores. The same applies to the calculation method of the porosity of the second layer 6b and the third layer 6c.

  In addition, image analysis software can be used to calculate the area of the pores. Moreover, the porosity calculated in one visual field may be regarded as the porosity of the first layer 6a, or the porosity is calculated in the same procedure in a plurality of visual fields, and the average value is calculated as the porosity of the first layer 6a. May be considered.

  The determination of the boundary between the first layer 6a and other parts will be described. First, in the same SEM image as described above, a first line is drawn with an interval of 1 μm from the boundary line between the support 2 and the interconnector layer 6 toward the interior of the interconnector layer 6. Then, the porosity in the region between the boundary line and the first line is measured. Next, the second line is drawn with an interval of 1 μm from the first line. Then, the porosity in the region between the first line and the second line is measured. If this porosity is less than 1%, the first line is defined as a boundary between the first layer 6a and another portion. That is, from the first line to the boundary between the support 2 and the interconnector layer 6 is regarded as the first layer 6a. If the porosity in the region between the first line and the second line is 1% or more, the third line is drawn with an interval of 1 μm from the second line. Similarly, the porosity in the region between the second line and the third line is obtained, and if it is less than 1%, the second line is set as a boundary between the first layer 6a and the other part. That is, the first layer 6a is considered from the second line to the boundary between the support 2 and the interconnector layer 6. If it is 1% or more, the fourth line is similarly drawn to determine the porosity. Thus, the porosity of the region having a width of 1 μm is measured, and the process is repeated until the porosity becomes less than 1%. And when it becomes less than 1%, what is necessary is just to make the line of the one front in front the boundary of the 1st layer 6a and another part.

The determination of the boundary between the second layer 6b and other parts will be described. First, in the same SEM image as described above, a first line is drawn with an interval of 1 μm from the surface of the interconnector layer 6 far from the support 2 toward the interior of the interconnector layer 6. Then, the porosity in the region between the surface and the first line is measured. Next, the second line is drawn with an interval of 1 μm from the first line. Then, the porosity in the region between the first line and the second line is measured. If this porosity is greater than 0.5%, the first line is defined as the boundary between the second layer 6b and other portions. That is, the first line to the surface of the interconnector layer 6 is regarded as the second layer 6b. If the porosity in the region between the first line and the second line is 0.5% or less, the third line is drawn with an interval of 1 μm from the second line. Similarly, the porosity in the region between the second line and the third line is obtained. If the porosity is greater than 0.5%, the second line is set as a boundary between the second layer 6b and the other part. That is, from the second line to the surface of the interconnector layer 6 is regarded as the second layer 6b. Moreover, if it is 0.5% or less, a 4th line | wire is drawn similarly and a porosity is calculated | required. Thus, the porosity of the region having a width of 1 μm is measured, and the process is repeated until the porosity becomes larger than 0.5%. And when it becomes larger than 0.5%, what is necessary is just to make the line of the one front one the boundary of the 2nd layer 6b and another part.

  The boundary of the third layer 6c is determined by the boundary between the first layer 6a and another part and the boundary between the second layer 6b and another part. That is, the boundary from the boundary of the first layer 6a to the boundary of the second layer 6b is regarded as the third layer 6b.

  Next, a confirmation method of “the first layer having a higher porosity than the other portions” will be described. As described above, after the boundary between the first layer 6a and the other part is determined, the porosity of the first layer 6a and the other part is calculated. And what is necessary is just to confirm that the porosity of the 1st layer 6a is higher than another part.

  In addition, a confirmation method of “the second layer has a lower porosity than other portions” will be described. As described above, after the boundary between the second layer 6b and the other part is determined, the porosity of the second layer 6b and the other part is calculated. And what is necessary is just to confirm that the porosity of the 2nd layer 6b is lower than another part.

  A confirmation method of “the porosity of the third layer is lower than that of the first layer and higher than that of the second layer” will be described. This may be confirmed by calculating the porosity of each layer after identifying the first layer, the second layer, and the third layer, and comparing the numerical values.

  Further, a confirmation method of “the third layer is thicker than the first layer and the second layer” will be described. This may be confirmed by measuring the thickness of each layer after identifying the first layer, the second layer, and the third layer, and comparing the numerical values.

(Production method)
An example of a method for manufacturing the cell 1 of the present embodiment described above will be described. However, various conditions such as the material, particle size, temperature, and coating method described below can be changed as appropriate. Hereinafter, the “molded body” refers to a state before firing.

First, for example, Ni and / or NiO powder, powder of rare earth oxide 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 calcined for 2 to 6 hours at 900-1000 degreeC 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. Then, an organic binder and a solvent are mixed with the mixed powder to prepare a fuel electrode layer slurry.

Also, a ZrO ₂ powder in which Y ₂ O ₃ is solid-dissolved, and a slurry obtained by adding toluene, a binder powder, a commercially available dispersant, etc., are formed into a sheet-like solid electrolyte layer by a method such as a doctor blade. Create a body.

  Then, 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 fuel electrode layer molded body side surface of the fuel electrode layer molded body and the solid electrolyte layer molded body on the fuel electrode layer molded body side is laminated on the support body molded body to form a molded body.

Subsequently, the interconnector layer material (for example, LaCrMgO ₃ oxide powder), NiO
A powder, an organic binder, and a solvent are mixed to prepare a slurry.

  In addition, in order to produce the slurry for the first layer, the second layer, and the third layer, the amount of the pore former is adjusted so that each layer has a desired porosity. The pore former is formed from a resin that scatters during firing, such as a cellulose resin.

  The pore diameter can be changed depending on the size of the pore former, and the porosity can be changed depending on the amount of the pore former.

  And when producing the interconnector layer 6 of the example shown in FIG. 2, after apply | coating the slurry for 1st layers on an electroconductive support body molded object and making it dry and producing a 1st layer molded object, The third layer slurry is applied on the one-layer molded body and dried to produce a third-layer molded body, and the second-layer slurry is applied and dried to produce a second-layer molded body. Create a body.

Moreover, when producing the interconnector layer 6 of the example shown in FIG. 3, the following method is taken, for example. First, a slurry is prepared from NiO powder and a pore former. Next, the prepared slurry is granulated with a spray dryer. The prepared granules, interconnector layer material (for example, LaCrMgO ₃ oxide powder), an organic binder and a solvent are mixed to prepare a slurry. What is necessary is just to produce the laminated molded object as mentioned above using this slurry. As a result, the pore former becomes pores in the interconnector layer, and the NiO powder becomes Ni constituting the inner walls of the pores.

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

Then, for _{example, La x Sr 1-x Co} y Fe 1-y O 3 having a predetermined particle size (hereinafter, simply referred to as LSCF) powders, an organic binder, a pore former, and a mixture of solvent cathode layer A slurry is prepared. This slurry is applied onto the solid electrolyte layer by screen printing to form a molded body for the air electrode layer. This slurry is applied onto the solid electrolyte layer by screen printing to form a molded body for the air electrode layer.

  Next, the laminate in which the air electrode layer formed body is formed on the solid electrolyte layer is fired at 1100 to 1200 ° C. for 1 to 3 hours. In this way, the cell 1 of the present embodiment having the structure shown in FIG. 1 can be manufactured.

  In the cell 1, after that, it is preferable to flow hydrogen gas through the gas flow path to reduce the support 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.

(Cell stack device)
FIG. 4 shows an example of a cell stack device configured by electrically connecting a plurality of the above-described cells in series via the conductive member 13, and (a) shows the cell stack device 11. The side view shown schematically, (b) is a cross-sectional view of the broken line portion of the cell stack device 11 of (a), and shows the portion surrounded by the broken line shown in (a). In addition, in (b), in order to clarify, the part corresponding to the part enclosed with the broken line shown by (a) is shown with the arrow.

The cell stack apparatus 11 includes a cell stack 12 in which a plurality of cells 1 are arranged in parallel and the cells 1 are connected by a conductive member 13. Further, end conductive members 14 that can be elastically deformed are provided at both ends of the plurality of cells 1 in the juxtaposed direction, and sandwich the plurality of cells 1 that are juxtaposed. Further, the end conductive member 14 is connected to a current drawing portion 15 for drawing a current generated by power generation of the cell stack 12 (cell 1). Further, the lower end of each cell 1 and the lower end of the end conductive member 14 are fixed to the gas tank 16 with an adhesive such as a glass sealing material.

  Since the cell stack apparatus 11 of the present embodiment also includes the cell 1 described above, the cell stack apparatus 11 with improved durability can be obtained.

(module)
Next, a module 18 in which the above-described cell stack device 11 is stored in the storage container 19 will be described with reference to FIG.

  The module 18 shown in FIG. 5 includes a reformer 20 for reforming raw fuel such as natural gas or kerosene to generate fuel gas for use in the cell 1. Arranged above. The fuel gas generated by the reformer 20 is supplied to the gas tank 16 via the gas flow pipe 21 and supplied to the gas flow path (not shown) provided inside the cell 1 via the gas tank 16. Is done.

  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 1 and the reformer 20 housed inside are taken out rearward.

  In such a module 18, since the cell stack device 11 with improved durability is accommodated, the module 18 with improved durability can be obtained.

(Module housing device)
Next, a module housing device 23 in which the module 18 described above and an auxiliary machine (not shown) for operating the module 18 are housed in an outer case will be described with reference to FIG.

  The module housing apparatus 23 shown in FIG. 6 divides the inside of the exterior case composed of the columns 24 and the exterior plate 25 into upper and lower portions by the partition plate 26, and the upper side thereof serves as the module storage chamber 27 that houses the module 18 described above. The lower side is configured as an auxiliary equipment storage chamber 28 for storing auxiliary equipment for operating the module 18.

  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 module storage device, the module 18 including the cell stack 11 with improved durability is stored, so that the module storage device 23 with improved durability 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, it may be a fuel battery cell in which an air electrode layer, a solid electrolyte layer, and a fuel electrode layer are arranged in this order on a support. Further, for example, a support that also serves as a fuel electrode layer may be used.

Moreover, although the fuel cell, the cell stack device using the fuel cell module, 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 applies water vapor and voltage to the cell. Thus, the present invention can also be applied to an electrolysis cell (SOEC) that generates hydrogen and oxygen (O ₂ ) by electrolyzing water vapor (water), an electrolysis cell stack device, an electrolysis module, and an electrolysis device including the same.

(Sample preparation)
A plurality of cells having different porosities of the first layer, the second layer, and the third layer were produced. Specifically, as shown in Table 1, ten samples (N = 10) were produced.

  The shape of the cell used in each sample was the same plate shape as in FIG. The length in the longitudinal direction of the cell was 20 cm, the length in the short direction of the cell was 26 mm, and the thickness was 2 mm.

The manufacturing method was the same as that described above. The NiO powder used for the production of the support molded body had an average particle size of 0.5 μm, and the Y ₂ O ₃ powder had an average particle size of 0.9 μm. The volume ratio of the support molded body after firing and reduction was 48% by volume for NiO and 52% by volume for Y ₂ O ₃ . As the electrolyte layer raw material powder, ZrO ₂ powder having a particle diameter of 0.8 μm by microtrack method in which 8 mol% of Y ₂ O ₃ was dissolved was used. The NiO powder used for producing the fuel electrode molded body had an average particle size of 0.5 μm, and the ZrO ₂ powder in which Y ₂ O ₃ was dissolved had an average particle size of 0.8 μm. The laminated molded body of the support molded body, the electrolyte layer sheet, and the fuel electrode molded body was calcined at 1000 ° C. for 3 hours. As the material of the interconnector layer, La (Mg _0.3 Cr _0.7 ) _0.96 O ₃ was used. For the interconnector layer, the first layer slurry, the third layer slurry, and the second layer slurry were sequentially applied onto the support molded body and dried to prepare an interconnector layer molded body. The laminated molded body produced as described above was co-fired at 1450 ° C. for 2 hours in an oxygen-containing atmosphere.

As the material for the air electrode, La _0.6 Sr _0.4 Co _0.2 Fe _0.8 O ₃ was used. The air electrode was formed by baking at 1100 ° C. for 4 hours. In the reduction treatment, hydrogen gas was allowed to flow inside the cell, the support and the fuel electrode were subjected to reduction treatment at 850 ° C. for 10 hours, and cooled. The porosity of each layer of the obtained cell was as shown in Table 1.

  About the obtained cell, the 1st layer, the 2nd layer, and the 3rd layer were specified by the method mentioned above, and the porosity of each layer was computed. In addition, the porosity of each layer was calculated | required using the image analysis apparatus from the 1000-times SEM photograph in arbitrary cross sections.

(Crack test and peel test)
In addition, a cell stack device having the configuration shown in FIG. did. This fuel gas supply and stop cycle was repeated 360 times. Then, about each of ten cells, the cross section of the interconnector layer was observed with the SEM image, and it was confirmed whether the interconnector layer had the crack. Table 1 shows the number of cells in which cracks occurred. Those having reached a length of 1 μm were recognized as cracks. Moreover, after this cycle test, it was also confirmed whether or not peeling occurred between the interconnector layer and the support for each of the 10 cells. Table 1 shows the number of cells where peeling occurred. The case where the length of the part where the interconnector layer and the support did not contact each reached 1 μm was recognized as peeling.

(Crack test result)
Sample No. In 1, the number of cells in which a crack occurred in the interconnector layer was six. This is because the porosity of the first layer was lower than other parts.

  Sample No. In samples 2 and 3, sample no. Compared with 1, the number of cells in which cracks occurred in the interconnector layer was small. This is because the porosity of the first layer was higher than the other parts.

  Sample No. 4, sample no. Compared with 2 and 3, the number of cells where cracks occurred in the interconnector layer was small. This is because the porosity of the first layer was 2% or more.

  Sample No. 5 to 13, sample No. Compared to 4, the number of cells in which cracks occurred in the interconnector layer was small. This is because the porosity of the first layer was 3% or more.

(Peel test results)
Sample No. In 9, 10, the number of cells in which peeling occurred between the interconnector layer and the support was three. This is because the porosity of the first layer was higher than 10%.

  Sample No. In sample No. 8, sample no. Compared with 9, 10, the number of cells in which peeling occurred between the interconnector layer and the support was small. This is because the porosity of the first layer was 10% or less.

  Sample No. 2-7, sample no. Compared to 8, the number of cells in which peeling occurred between the interconnector layer and the support was small. This is because the porosity of the first layer was 9% or less.

1: Cell 2: Support 2a: Gas channel 3: First electrode layer (fuel electrode layer)
4: Solid electrolyte layer 5: Second electrode layer (air electrode layer)
6: interconnector layer 6a: first layer 6b: second layer 6c: third layer

Claims (9)

A support having a columnar shape, a pair of opposed surfaces, a gas flow path for flowing fuel gas along the longitudinal direction therein, and containing Ni;
A first electrode layer provided on a first surface of the pair of surfaces of the support;
A solid electrolyte layer provided on the first electrode layer;
A second electrode layer provided on the solid electrolyte layer;
An interconnector layer provided on a second surface of the pair of main surfaces of the support is provided, and the interconnector layer is located closest to the support and has a higher porosity than other portions. A cell having a first layer. The interconnector layer contains Ni,
The interconnector layer has a second layer at a position farther from the support than the first layer,
The cell according to claim 1, wherein the second layer has a lower porosity than other portions. The cell according to claim 1 or 2, wherein the porosity of the first layer is 2 to 10%. The interconnector layer further includes a third layer between the first layer and the second layer, and the porosity of the third layer is lower than that of the first layer and higher than that of the second layer. 4. A cell according to claim 2 or claim 2 quoting claim 2, characterized in that The cell according to claim 4, wherein the third layer is thicker than the first layer and the second layer. The interconnector layer contains Ni,
The cell according to any one of claims 1 to 5, wherein at least a part of the inner walls of the pores in the interconnector layer is made of Ni.   A cell stack apparatus comprising a cell stack in which a plurality of the cells according to claim 1 are arranged. A module, wherein the cell stack device according to claim 7 is stored in a storage container.   A module housing apparatus comprising: the module according to claim 8; and an auxiliary machine for operating the module.