JP2017045566A - Cell, cell stack device, module, and module housing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cell, cell stack device, a module, and a module housing device.SOLUTION: A cell 1 includes a flat support 2 having the length direction and width direction internally provided with a gas flow path 2a, and having a pair of principal surfaces n and a pair of side faces m, a fuel electrode 3 provided at least on one principal surface of the support 2, a solid electrolyte layer 4 covering the fuel electrode 3, and provided from one principal surface n across the pair of side faces m of the support 2, and an air electrode 5 provided to face the fuel electrode 3 on the solid electrolyte layer 4. In the width direction, the support 2 has an end side first area A, a central side second area B, and a third area C located between the first area A and second area B, where the second area B has a porosity larger than that of the third area C.SELECTED DRAWING: Figure 1

Description

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

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

  Moreover, in the cell of patent document 1, the laminated body which has a fuel electrode, a solid electrolyte layer, and an air electrode is provided on the support body. This support is described as having an open porosity of preferably 35-50%.

JP 2010-129269 A

  However, Patent Document 1 did not mention the porosity distribution of the support. Therefore, it has been difficult to improve the power generation efficiency.

  An object of the present invention is to provide a cell, a cell stack device, a module, and a module housing device with improved power generation efficiency.

  The cell of the present invention has a length direction and a width direction in which a gas flow path is provided, and has a plate-like support body having a pair of main surfaces and a pair of side surfaces, and at least the support body A fuel electrode provided on one main surface, a solid electrolyte layer covering the fuel electrode, provided from the one main surface of the support to the pair of side surfaces, and the solid electrolyte layer, An air electrode provided so as to face the fuel electrode, and the support body has a first region on the end side, a second region on the center side, and the second region in the width direction. And a third region located between the first region and the second region, wherein the second region has a higher porosity than the third region.

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

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

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

The cell of the present invention can be a cell with improved power generation efficiency. Also in a cell stack device, a module, and a module housing device using such a cell, power generation efficiency can be improved.

The structure of the cell of this embodiment is shown, (a) is the cross-sectional view, (b) is a perspective view of (a). It is a perspective view which shows the structure of the cell of other embodiment. It is a longitudinal cross-sectional view of the cell of FIG. The cell stack apparatus provided with the cell of FIG. 1 is shown, (a) is a side view, (b) is a cross-sectional view about the broken-line part of (a). It is an external appearance perspective view which shows an example of the module which comprises the cell stack apparatus of FIG. 4, and shows the state before accommodating a cell stack apparatus in a storage container. It is a perspective view which shows an example of the module accommodating apparatus which comprises the module of FIG.

  A cell, a cell stack, 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.

  Hereinafter, an example of a solid oxide fuel cell will be described as a cell constituting the cell stack.

(Cell structure)
FIG. 1 shows an example of a cell according to the present embodiment, in which (a) is a transverse sectional view and (b) is a perspective view of (a). In both drawings, a part of each component of the cell 1 is shown in an enlarged manner.

  The cell 1 includes a conductive support (hereinafter simply referred to as a support) 2, a fuel electrode 3, a solid electrolyte layer 4 (hereinafter simply referred to as an electrolyte layer), and an air electrode 5.

  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 2 has a flat plate shape having a pair of main surfaces n and a pair of side surfaces m. In the example shown in FIG. 1, the pair of main surfaces n are parallel to 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.

  A plurality of gas flow paths 2 a are provided in the support 2 so as to penetrate in the vertical direction L at appropriate intervals. Further, the cell 1 has a structure provided so that various members described later surround the outer periphery of the support 2.

  As shown in FIG. 1, the fuel electrode 3 is provided on at least one main surface n (lower surface in FIG. 1) of the support 2. In the example shown in FIG. 1, the fuel electrode 3 is disposed on the support 2 so as to cover one main surface n of the support 2 and the arcuate surfaces m on both sides. Further, since the fuel electrode 3 only needs to be disposed at a position facing the air electrode 5, for example, the fuel electrode 3 does not extend to the other main surface n (upper surface in FIG. 1) and the arcuate surface m, but one main surface. The fuel electrode 3 may be disposed only at n. The fuel electrode 3 is a porous body.

  As shown in FIG. 1, the electrolyte layer 4 covers the fuel electrode 3 and is provided from one main surface n to a pair of side surfaces m of the support 2. Moreover, the electrolyte layer 4 of this example is a solid oxide form.

  As shown in FIG. 1, the air electrode 5 is provided on the electrolyte layer 4 so as to face the fuel electrode 3. In the example shown in FIG. 1, the support 2 is disposed on the one main surface n side and outside the electrolyte layer 4. The air electrode 5 is a porous body.

  The interconnector layer 6 is disposed on the other main surface n where the fuel electrode 3 and the electrolyte layer 4 of the support 2 are not laminated.

  In the cell 1 described above, the portion where the fuel electrode 3, the electrolyte layer 4, and the air electrode 5 are stacked generates power as a power generation element portion. In order to generate power, an oxygen-containing gas such as air is allowed to flow outside the air electrode 5, and a fuel gas (hydrogen-containing gas) is allowed to flow through the gas flow path 2 a in the support 2, so that the fuel gas is supplied to the fuel electrode 3. Then, the fuel electrode 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 3 and the electrolyte layer 4 extend from one main surface (the lower surface of FIG. 1A) to a part of the other main surface n (the upper surface) via the arcuate surfaces m at both ends. The both ends of the electrolyte layer 9 are laminated and joined to both ends of the interconnector layer 6. As a result, the support 2 is surrounded by the electrolyte layer 4 and the interconnector layer 6, and the fuel gas flowing through the inside does not leak to the outside. In other words, the fuel gas supplied to the fuel electrode 3 and the oxygen-containing gas supplied to the air electrode 5 are blocked off with the electrolyte layer 4 as a boundary.

  Therefore, when viewed from the side surface shown in FIG. 1B, the interconnector layer 6 having a rectangular planar shape is arranged so as to cover from the upper end to the lower end in the longitudinal direction L of the support 2. The left and right end portions of each are joined so as to overlap the surfaces of both end portions of the electrolyte layer 4.

(Description of each member of the cell)
The support 2 is required to be gas permeable in order to allow the fuel gas to pass to the fuel electrode 3 and to be conductive in order to be collected by being connected to the interconnector layer 6. 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.

When the support 2 is produced by co-firing with the fuel electrode 3 or the electrolyte layer 4 in producing the cell 1, the support 2 is composed of an iron group metal component and an inorganic oxide such as Ni and / or It consists of NiO and specific rare earth oxides. 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 electrolyte layer 4, and is Y, Lu, Yb, Tm, Er, Ho, Dy, Gd, Sm. , Rare earth oxides containing at least one element selected from the group consisting of Pr are used, and 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 or reaction with Ni and / or NiO, and the thermal expansion coefficient is the same as that of the electrolyte layer 4 and is inexpensive. terms is _composed of at least one of Y 2 _{O 3} and _Yb 2 _{O 3.} In the present embodiment, Ni and / or NiO: rare earth oxide = 35: 65 to 65 in that the good conductivity of the support 2 is maintained and the thermal expansion coefficient is approximated to that of the electrolyte layer 4. Is present in a volume ratio of 35. The support 2 may contain other metal components and oxide components as long as required characteristics are not impaired.

Furthermore, according to the present embodiment, the length of the main surface n of the support 2 (the length of the support 2 in the width direction W) is 15 to 60 mm, and the length of the arcuate surface m (the length of the arc) is The thickness of the support 2 (thickness between the main surfaces n) is 1.5 to 5 mm, and the length of the support 2 in the L direction is 10 to 50 cm.

The fuel electrode 3 causes an electrode reaction. In the present embodiment, the fuel electrode 3 is made of porous conductive ceramics. For example, a material composed of ZrO ₂ and Ni and / or NiO in which a rare earth oxide is dissolved, or a material composed of CeO ₂ and Ni and / or NiO in which another rare earth oxide is dissolved. 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 the _ZrO 2 and (YSZ) and Ni and / or NiO solid solution. In the present embodiment, the content of ZrO ₂ in which the rare earth oxide in the fuel electrode 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. Content is 65-35 volume%. Further, the open porosity of the fuel electrode 3 is, for example, in the range of 15% or more, particularly 20 to 40%, and the thickness thereof is 1 to 30 μm.

The electrolyte layer 4 has a function as an electrolyte that bridges ions between the fuel electrode 3 and the air electrode 5, and at the same time has a gas barrier property to prevent leakage between the fuel gas and the oxygen-containing gas. Is needed. 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 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 electrolyte layer 4 is 10 to 40 μm. In particular, in order to suppress gas permeation in the electrolyte layer 4, the thickness is 20 to 40 μm.

The air electrode 5 is not particularly limited as long as it is generally used. For example, the air electrode 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 5 is required to have gas permeability, and the open porosity is preferably 20% or more, particularly preferably in the range of 30 to 50%.

For the interconnector 6, a lanthanum chromite-based perovskite oxide (LaCrO ₃ -based oxide) or a lanthanum strontium titanium-based perovskite oxide (LaSrTiO ₃ -based oxide) is preferably used. These materials have conductivity and are neither reduced nor oxidized even when they come into contact with a fuel gas (hydrogen-containing gas) and an oxygen-containing gas (air or the like). Further, the interconnector 6 must be dense to prevent leakage of the fuel gas flowing through the gas flow path 2a formed in the support substrate 2 and the oxygen-containing gas flowing outside the support substrate 2, It is preferable to have a relative density of 93% or more, particularly 95% or more.

  By the way, when the porosity of the support 2 of the cell 1 is uniform in the width direction, it does not have sufficient gas permeability on the center portion side in the width direction of the support 2 and therefore passes through the gas flow path 2a. It is difficult for the gas to reach the fuel electrode 3. Therefore, it has been difficult to improve the power generation efficiency.

  Therefore, in the present embodiment, the support 2 is positioned between the first region A on the end side, the second region B on the center side, and the first region A and the second region B in the width direction. The second region B has a porosity higher than that of the third region C.

With this configuration, in the second region B having a relatively high porosity, the gas that has passed through the gas flow path 2 a is likely to diffuse inside the support 2 and reach the fuel electrode 3. Further, by keeping the porosity of the third region C smaller than that of the second region B, it is possible to prevent the gas from being excessively diffused in the first region A where the whole is not covered with the air electrode 5 and the power generation amount is small. it can. Therefore, the power generation efficiency of the cell 1 can be improved.

  Here, in the example shown in FIG. 1, the first region A refers to a region outside in the width direction w from the overlapping portion S where the end of the interconnector layer 6 and the end of the electrolyte layer 4 overlap.

  Further, the region between the pair of overlapping portions S and the outer region in the width direction w is the third region C, and the central region is the second region B. The width of the third region C is the same as the width of the first region A. A region between the pair of overlapping portions S and excluding the widths of the third regions C on both sides is the second region B.

  In the present embodiment, the porosity of each region is measured as follows. First, a so-called “resin filling” process is performed on the support so that the resin enters the pores of the support. The surface of the support subjected to the “resin filling” treatment is mechanically polished. By performing image processing on an image obtained by observing the microstructure of the mechanically polished surface with a scanning electron microscope (SEM), pores (portions where the resin has entered) and pores The area of the part which is not (the part where the resin has not entered) is calculated. The ratio of the “area of the pore portion” to the “total area (the area of the pore portion and the area of the non-pore portion)” is defined as the “porosity” of the support (support substrate).

  The number of portions to be observed with the SEM is 3 to 5 in each region, an average value is taken in each region, and the value is taken as the porosity in each region. In the second region B and the third region C, arbitrary 3 to 5 locations at a certain distance from the other main surface on which the interconnector layer 6 is provided are selected.

  Further, the porosity of the second region B is preferably 1.01 to 1.5 times that of the third region C. In the case of 1.01 times or more, the porosity of the second region B is sufficiently large, so that the gas easily diffuses into the central portion of the support 2 and easily reaches the fuel electrode 3. Therefore, power generation efficiency can be improved. Moreover, in the case of 1.5 times or less, it can suppress that there are too many pores in the second region B. Therefore, since a current path can be secured in the second region B, power generation efficiency can be improved.

The first region A may have a larger porosity than the third region C. When the support 2 has a higher coefficient of thermal expansion than the electrolyte layer 4, stress due to the difference in thermal expansion occurs between both members. This stress tends to increase at the side surface m of the support 2. Therefore, damage such as cracks is likely to occur in the fuel electrode 3 between the support 2 and the electrolyte layer 4. Further, when the fuel electrode 3 is provided only on the one main surface n and the support 2 and the electrolyte layer 4 are in direct contact with each other on the side surface m, peeling between the two members was likely to occur. In such cases, even if the first region A has a higher porosity than the third region C, and the thermal expansion coefficient of the support 2 is relatively high, the amount of thermal expansion is increased by the amount of the higher porosity. Is suppressed. Accordingly, the difference in thermal expansion from the electrolyte layer 4 is reduced, and the stress is relaxed. Therefore, damage to the fuel electrode 3 or separation between the support 2 and the electrolyte layer 4 can be suppressed on the side surface m of the support 2. The case where the support 2 has a higher coefficient of thermal expansion than the electrolyte layer 4 means, for example, that the support 2 is made of Ni and / or NiO and Y ₂ O ₃ , and the electrolyte layer 4 contains Y ₂ O ₃ . This is the case of ZrO ₂ .

In the example shown in FIG. 1, the diameter of the gas flow path 2 a in the third region C is larger than the diameter of the gas flow path 2 a in the first region A. In this case, a crack generated by the stress generated in the overlapping portion S may reach the gas flow path 2a in the third region C. This is because when the diameter of the gas flow path 2a is increased, the distance between the overlapping portion S (the tip portion of the electrolyte layer 4) and the gas flow path 2a is shortened. Here, as described above, by making the porosity of the third region C smaller than that of the first region A, the cracks generated in the overlapping portion S are difficult to propagate inside the support body 2.
Therefore, a crack is connected to the gas flow path 2a, and it can suppress that the support body 2 fractures | ruptures.

  Further, the porosity of the first region A is preferably 1.01 to 1.5 times that of the third region C. In the case of 1.01 times or more, the porosity of the first region A becomes high, so that the stress due to the difference in thermal expansion is relaxed between the electrolyte layer 4 and the side surface of the support 2. Therefore, damage to the fuel electrode 3 or separation between the support 2 and the electrolyte layer 4 can be suppressed. Moreover, since the porosity of the 1st area | region A is not too high when it is 1.5 times or less, intensity | strength can be maintained in the side surface side of the support body 2. FIG.

(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, 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.

  Moreover, in order to set the first region, the second region, and the third region to a desired porosity, the amount of the pore former inside the support molded body is adjusted. For example, when setting the clay in the extruder, the amount of the pore former in the clay may be changed depending on the position. In addition, for example, a molded body may be prepared in blocks for each region by extrusion molding, and may be combined later by calcination or the like.

  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. Thereafter, an organic binder and a solvent are mixed with the mixed powder to prepare a fuel electrode slurry.

Further, a slurry obtained by adding toluene, a binder powder (hereinafter, a polymer higher than the binder powder attached to the ZrO ₂ powder, for example, an acrylic resin), a commercially available dispersant, etc. to the ZrO ₂ powder in which Y ₂ O ₃ is solid-dissolved. The sheet is molded by a method such as a doctor blade to produce a sheet-shaped electrolyte layer molded body.

  And the slurry for fuel electrodes is apply | coated on the obtained sheet-like electrolyte layer molded object, it dries, a fuel electrode molded object is formed, and a sheet-like laminated molded object is formed. The surface on the fuel electrode molded body side of the sheet-shaped laminated molded body of the fuel electrode molded body and the electrolyte layer molded body is laminated on the conductive support molded body to form a molded body.

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

  Thereafter, the interconnector layer slurry is applied to the upper surface of the support molded body so that both end portions of the interconnector layer molded body are laminated on both end portions of the electrolyte layer molded body, thereby producing a laminated molded body. .

  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, a desired particle size _{La x Sr 1-x CoyFe 1} -y O 3 ( hereinafter, simply referred to as LSCF) powders, an organic binder, a pore former, and mixed to the slurry for the air electrode of the solvent Make it. This slurry is applied onto the electrolyte layer by screen printing to form an air electrode molded body. This slurry is applied onto the electrolyte layer by screen printing to form an air electrode molded body.

  Next, the laminate in which the air electrode molded body is formed on the 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, it is preferable that hydrogen gas is then passed through the gas flow path to reduce the support 2 and the fuel electrode 3. In that case, it is preferable to perform a reduction process at 750-1000 degreeC for 5 to 20 hours, for example.

(Other embodiments)
FIG. 2 is a perspective view showing the structure of a cell according to another embodiment. FIG. 3 is a longitudinal sectional view of the cell of FIG.

  The cell 10 shown in FIGS. 2 and 3 is an example of a so-called horizontal stripe type cell, and includes an insulating support 1. Inside the support 2, a plurality of gas flow paths 2 a are formed penetrating in the longitudinal direction L of the cell 10 at appropriate intervals.

  The support 2 is provided on each of the pair of main surfaces so that a plurality of sets are adjacent to each other, with the porous fuel electrode 3, the dense solid electrolyte layer 4 and the porous air electrode 5 as one set. These are electrically connected by a dense interconnector layer 6. The portion where the fuel electrode 3, the solid electrolyte layer 4 and the air electrode 5 overlap functions as the element portion a that generates power. That is, power is generated by flowing an oxygen-containing gas such as air outside the air electrode 5 and flowing a fuel gas (hydrogen-containing gas) through the gas flow path 2a in the support 2 and heating it to a predetermined operating temperature. Further, the fuel electrode 3 may be in a form in which at least a part thereof is embedded in the support 1.

  Moreover, when the support body 2 is used as the insulating support body 2, it is preferable that the support body 2 is formed of, for example, Mg oxide (MgO), Ni and / or NiO, and a specific rare earth oxide. As the rare earth element oxide, the same ones as described above can be used. Further, MgO is 70 to 80% by volume, rare earth element oxide is 10 to 20% by volume, Ni and / or NiO is 10 to 25% by volume, and the total resistivity is preferably 10 Ω · cm or more.

  Also in this horizontally striped cell 10, the porosity of the second region B is larger than that of the third region C, as shown in FIG. As a result, the fuel gas easily reaches the fuel electrode 3 and the power generation efficiency is improved.

  In the horizontal stripe cell 10, the first region A is a region that is 5% of the length of the cell 10 in the width direction w. The total of the first areas A located at both ends in the width direction of the cell 10 is 10%. The third region C is a region that is 5% of the length of the cell 10 in the width direction w. The total of the third regions C located at both ends in the width direction of the cell 10 is 10%. The second region B is the remaining 80% central portion.

(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 18. The side view shown schematically, (b) is a cross-sectional view of the broken line portion of the cell stack device 18 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). 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 sealant.

  Also in the cell stack device 11 of the present embodiment, since the cell 1 described above is provided, the cell stack device 11 in which a decrease in output density is suppressed 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 a gas flow path (not shown) provided inside the cell 1 via the gas tank 16. Is done.

  FIG. 5 shows a state where 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 power generation efficiency is improved and the cell stack device 11 is accommodated, the module 18 with improved power generation efficiency 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 having the cell stack 11 with improved power generation efficiency is stored, so that the module storage device 23 with improved power generation efficiency 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 cell arranged in the order of an air electrode, an electrolyte layer, and a fuel electrode on a support. Furthermore, for example, a support that also serves as a fuel electrode 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), and an electrolysis cell stack device, an electrolysis module, and an electrolysis device including the electrolysis cell.

(Sample preparation)
A plurality of cells having different porosity in each region were produced. Specifically, as shown in Table 1, nine samples (N = 9) 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 width 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. The interconnector layer slurry was applied to the laminate and 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.

  Here, Sample No. In the supports 1 to 9, the porosity of each region was controlled as shown in Table 1 by adjusting the amount of the pore former.

(Measurement of porosity)
Sample No. after fabrication as described above. As described above, the supports 1 to 9 were mechanically polished after the “resin filling” process, and image processing was performed on the obtained SEM images to determine the porosity of each region.

  The number of portions observed with the SEM was three in each region, the average value was taken in each region, and the value was taken as the porosity in each region. Note that, in the second region B and the third region C, arbitrary three locations separated by 0.5 mm from the other main surface provided with the interconnector layer were selected.

(Power generation performance test)
First, hydrogen gas was allowed to flow through the cell of each sample at a temperature of 750 ° C., and the output density of the cell was measured. The power density results are shown in Table 1.

(Durability test of support)
In this test, 10 cells each serving as each sample were produced. And the presence or absence of the crack generation | occurrence | production in the support body of the cell after said reduction process was confirmed. Confirmation of the crack confirmed whether the crack generate | occur | produced in the 3rd area | region from the overlap part. Cracks were observed with SEM images. Those having reached a length of 1 μm were recognized as cracks. Table 1 shows the number of cells with cracks.

(Fuel electrode durability test)
In this test, 10 cells each serving as each sample were produced. Each cell was subjected to a thermal cycle test 10 times of “a pattern in which the ambient temperature is raised from room temperature to 750 ° C. in 1 hour and then lowered from 750 ° C. to room temperature in 2 hours”.

  And it was confirmed whether the fuel electrode in the side surface side of the support body of the cell after this test had cracked. Cracks were observed with SEM images. Those having reached a length of 1 μm were recognized as cracks. Table 1 shows the number of cells in which cracks occurred in the fuel electrode on the side surface of the support.

(Power generation performance test results)
As is clear from Table 1, sample No. In 1, the output density was small. This is because the second region has a lower porosity than the third region.

  Sample No. 2 and 9, sample no. Compared with 1, the output density was higher. This is because the second region has a higher porosity than the third region.

  Sample No. 3 to 8, sample No. Compared with 2 and 9, the output density was high. This is because the porosity of the second region was 1.01 to 1.5 times that of the third region.

(Durability test results of support)
Sample No. 4-9, sample No. Compared with 1 to 3, the generation of cracks in the third region could be suppressed. This is because the porosity of the third region was lower than that of the first region.

(Fuel electrode durability test results)
Sample No. 4 sample No. 4 Compared with 1-3, generation | occurrence | production of the crack in a fuel electrode was able to be suppressed. This is because the first region has a higher porosity than the third region.

  Sample No. 5-9, sample no. Compared with 4, it was possible to suppress the occurrence of cracks at the fuel electrode. This is because the porosity of the first region is 1.01 or more times that of the third region.

1: cell 2: support A: first region B: second region C: third region 3: fuel electrode 4: solid electrolyte layer 5: air electrode 6: interconnector layer

Claims (7)

The gas flow path has a length direction and a width direction provided inside, a flat plate-like support body having a pair of main surfaces and a pair of side surfaces;
A fuel electrode provided on at least one main surface of the support;
A solid electrolyte layer covering the fuel electrode and provided from the one main surface of the support to the pair of side surfaces;
An air electrode provided on the solid electrolyte layer so as to face the fuel electrode;
The support is in the width direction,
A first region on the end side;
A second region on the center side;
A third region located between the first region and the second region,
The second region has a porosity higher than that of the third region. The cell according to claim 1, wherein the porosity of the second region is 1.01 to 1.5 times that of the third region. The cell according to claim 1, wherein the first region has a larger porosity than the third region. The cell according to claim 3, wherein the porosity of the first region is 1.01 times or more that of the third region.   A cell stack apparatus comprising a cell stack in which a plurality of the cells according to claim 1 are arranged.   A module in which the cell stack device according to claim 5 is stored in a storage container.   A module housing apparatus comprising: the module according to claim 6; and an auxiliary machine for operating the module.