JP2018018628A - Cell stack device, fuel cell module, and fuel cell device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cell stack device, a fuel cell module and a fuel cell device which are improved in reliability .SOLUTION: A cell stack device comprises: a cell stack in which a plurality of columnar cells are arranged; a manifold for supplying a reaction gas to the plurality of cells; and a seal material made of glass for fixing one end of the plurality of cells to the manifold. The seal material includes an outside region located outside the manifold in a longitudinal direction of the cell, and an inner region located inside the manifold in the longitudinal direction of the cell. A thermal expansion coefficient of the seal material is greater than a thermal expansion coefficient of the cell. A difference between thermal expansion coefficients of the inner region and the cell is smaller than a difference between thermal expansion coefficients of the outer region and the cell.SELECTED DRAWING: Figure 3

Description

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

  2. Description of the Related Art In recent years, a cell stack device in which a plurality of fuel battery cells, which are cells capable of obtaining electric power using a fuel gas (hydrogen-containing gas) and an oxygen-containing gas (air), are arranged as next-generation energy is known. ing. Various fuel cell modules in which a cell stack device is housed in a storage container and fuel cell devices in which a fuel cell module is housed in an outer case have been proposed (see, for example, Patent Document 1).

  Such a cell stack device is configured by fixing one end of a fuel cell to a manifold with a sealing material. (For example, see Patent Document 2.)

JP 2007-59377 A International Publication No. 2015-163277

  In the cell stack apparatus as described above, cracks may occur due to the stress generated at the joint between the fuel cell and the sealing material due to the difference in thermal expansion between the fuel cell and the sealing material.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a cell stack device, a fuel cell module, and a fuel cell device that suppress the occurrence of cracks and have improved reliability.

  The cell stack device of the present invention includes a cell stack in which a plurality of columnar cells are arranged, a manifold for supplying a reaction gas to the plurality of cells, and one end of the plurality of cells in the manifold. A sealing material made of glass for fixing, and the thermal expansion coefficient of the sealing material is larger than the thermal expansion coefficient of the cell, the outer region located outside the manifold in the longitudinal direction of the cell, and the cell An inner region located on the inner side of the manifold in the longitudinal direction, and a difference in thermal expansion coefficient between the inner region and the cell is smaller than a difference in thermal expansion coefficient between the outer region and the cell. It is characterized by.

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

  The fuel cell device of the present invention is characterized in that the fuel cell module and an auxiliary machine for operating the fuel cell module are housed in an outer case.

  The cell stack device of the present invention can be a cell stack device with improved reliability.

The fuel cell module of the present invention can be a fuel cell module with improved reliability.

  Furthermore, the fuel cell device of the present invention can be a fuel cell device with improved reliability.

The cell stack apparatus of this embodiment is shown, (a) is the longitudinal cross-sectional view which shows a cell stack apparatus roughly, (b) is a cross-sectional view which expands and shows a part of (a). It is sectional drawing which expands and shows the site | part of the broken line A of the cell stack apparatus shown in FIG. It is an enlarged view of the site | part of the broken line B of FIG. It is a perspective view which shows an example of the fuel cell module of this embodiment. It is sectional drawing of the fuel cell module shown in FIG. It is a disassembled perspective view which shows roughly an example of the fuel cell apparatus of this embodiment.

  Hereinafter, the cell stack device of this embodiment will be described with reference to the drawings. 1A and 1B show a cell stack device according to the present embodiment, in which FIG. 1A is a longitudinal sectional view schematically showing the cell stack device, and FIG. 1B is a transverse sectional view showing a part of FIG. . In the following drawings, the same components are described using the same reference numerals.

  The cell stack device shown in FIG. 1 is a fuel cell stack device in which a plurality of fuel cells that are cells are arranged. In the following description, a fuel cell is described as an example.

  A cell stack device 1 shown in FIG. 1 has a cell stack 2 including a plurality of columnar fuel cells 3. The fuel battery cell 3 has a gas flow path 14 therein, and a cross section having a pair of opposing flat surfaces is flat and has an inner electrode layer on one flat surface of the columnar conductive support 13 as a whole. The fuel electrode layer 9, the solid electrolyte layer 10, and the air electrode layer 11 as the outer electrode layer are sequentially laminated, and the interferometer is formed on the other flat surface where the air electrode layer 11 is not formed. The connector 12 is laminated. And the fuel cell 3 is electrically connected in series by arrange | positioning via the electrically-conductive member 4 between the adjacent fuel cells 3. Note that a conductive bonding material 15 is provided on the outer surface of the interconnector 12 and the outer surface of the air electrode layer 11, and the conductive member 4 is connected to the air electrode layer 11 and the interconnector 12 via the bonding material 15. By doing so, the contact between them becomes an ohmic contact, the potential drop is reduced, and the deterioration of the conductive performance can be effectively suppressed.

  And the lower end of each fuel cell 3 which comprises the cell stack 2 is being fixed to the manifold 7 for supplying the reaction gas to the fuel cell 3 with the sealing materials 16, such as glass. The sealing material 16 will be described later. Further, in the cell stack device 1 shown in FIG. 1, an example in which a hydrogen-containing gas (fuel gas) is supplied as a reaction gas from the manifold 7 to the gas flow path 14 is shown. Is connected to a fuel gas supply pipe 8.

  In addition, the elastically deformable end portion that sandwiches the cell stack 2 from both ends in the arrangement direction of the fuel cells 3 (X direction shown in FIG. 1) via the conductive member 4, and the lower end is fixed to the manifold 7. A conductive member 5 is provided. Here, in the end conductive member 5 shown in FIG. 1, current generated by power generation of the cell stack 2 (fuel cell 3) having a shape extending outward along the arrangement direction of the fuel cells 3 is externally applied. A current drawing portion 6 for drawing out is provided.

By the way, in the cell stack device 1, the temperature of the fuel cell 3 is controlled by combusting the fuel gas (excess fuel gas) discharged from the gas flow path 14 on the upper end side of the fuel cell 3. Can be raised. Thereby, the start-up of the cell stack apparatus 1 can be accelerated.

  The manifold 7 includes a gas case 7b and a frame 7a that is disposed on the gas case 7b and includes an opening. The lower end portion of the fuel battery cell 3 is surrounded by a frame body 7a, and the lower end portion of the fuel battery cell 3 is fixed by a sealing material 16 filled inside the frame body 7a. The gas case 7 b has an opening on the upper surface for supplying fuel gas to the gas flow path 14 of the fuel cell 3. The openings of the frame body 7a and the gas case 7b are closed by the fuel cell 3 and the sealing material 16. Thereby, parts other than the gas flow path 14 of the fuel battery cell 3 are airtightly sealed.

The sealing material 16 is preferably a material having insulating properties and heat resistance of 800 to 1000 ° C., for example, glass (especially amorphous glass or glass containing crystal) is used. be able to. Specifically, a SiO ₂ —MgO—B ₂ O ₃ —Al ₂ O ₃ —CaO system or a SiO ₂ —MgO—B ₂ O ₅ —ZnO system can be used.

  Instead of the frame body 7a, a lid member (not shown) having an insertion port corresponding to the lower end of each fuel cell 3 may be provided in the gas case 7b. In this case, the fuel cell 3 is fixed to the insertion port by the sealing material 16.

  Below, each member which comprises the fuel cell 3 shown in FIG. 1 is demonstrated.

As the fuel electrode layer 9, generally known ones can be used. For example, porous conductive ceramics such as ZrO ₂ in which a rare earth element oxide is dissolved (referred to as stabilized zirconia, partially stable). And Ni and / or NiO can be used.

The solid electrolyte layer 10 has a function as an electrolyte for bridging electrons between electrodes, and at the same time has a gas barrier property to prevent leakage between the fuel gas and the oxygen-containing gas. 3 to 15 mol% of rare earth element oxide is formed from ZrO ₂ as a solid solution. In addition, as long as it has the said characteristic, you may use another material.

The air electrode layer 11 is not particularly limited as long as it is generally used. For example, a conductive ceramic made of a so-called ABO ₃ type perovskite oxide can be used. The air electrode layer 11 has gas permeability, and for example, the open porosity is preferably 20% or more, particularly preferably in the range of 30 to 50%.

The interconnector 12 can be made of conductive ceramics. Since the interconnector 12 is in contact with a fuel gas (hydrogen-containing gas) and an oxygen-containing gas (air or the like), the interconnector 12 needs to have reduction resistance and oxidation resistance. Therefore, the lanthanum chromite perovskite oxide (LaCrO ₃ oxide) is preferably used. The interconnector 12 is dense in order to prevent leakage of fuel gas flowing through the plurality of gas flow paths 14 formed in the conductive support 13 and oxygen-containing gas flowing outside the conductive support 13. For example, it is preferable to have a relative density of 93% or more, particularly 95% or more.

The conductive support 13 is gas permeable in order to allow the fuel gas to permeate to the fuel electrode layer 9, and is conductive in order to collect current via the interconnector 12. Therefore, for example, conductive ceramics or cermet can be used as the conductive support 13. In producing the fuel cell 3, when producing the conductive support 13 by co-firing with the fuel electrode layer 9 or the solid electrolyte layer 10, an iron group metal component and a specific rare earth oxide (Y ₂ O ₃ , The conductive support 13 is preferably formed from Yb ₂ O ₃ or the like. The conductive support 13 preferably has an open porosity of 30% or more, particularly 35 to 50% in order to provide gas permeability, and the conductivity is 300 S / cm or more, In particular, it is preferably 440 S / cm or more.

  Although not shown, an intermediate layer may be provided. As a result, the solid electrolyte layer 10 and the air electrode layer 11 are firmly joined, and the solid electrolyte layer 10 component and the air electrode layer 11 component are interposed between the solid electrolyte layer 10 and the air electrode layer 11. It can suppress that the reaction layer with high electrical resistance is formed by reaction.

Here, the intermediate layer may have a composition containing Ce (cerium) and other rare earth elements, for example,
(1): (CeO ₂ ) _1-x (REO _1.5 ) _x
In the formula, RE is at least one of Sm, Y, Yb, and Gd, and x is a number that satisfies 0 <x ≦ 0.3.
It is preferable to have the composition represented by these. 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. .

  Also, the intermediate layer can be made into two layers. As a result, the solid electrolyte layer 10 and the air electrode layer 11 are firmly bonded, and the components of the solid electrolyte layer 10 and the components of the air electrode layer 11 react to form a reaction layer with high electrical resistance. Further suppression can be achieved.

  Although not shown, an adhesion layer can be provided between the interconnector 12 and the conductive support 13. Thereby, the difference in thermal expansion coefficient between the interconnector 12 and the conductive support 13 can be reduced.

The adhesion layer can have a composition similar to that of the fuel electrode layer 9, for example, ZrO ₂ (referred to as stabilized zirconia) in which a rare earth element oxide such as YSZ is dissolved, Ni and / or NiO can do. In addition, it is preferable that ZrO _{2 in} which the rare earth element oxide is dissolved and Ni and / or NiO have a volume ratio of 40:60 to 60:40.

  FIG. 2 is an enlarged cross-sectional view of a portion indicated by a broken line A shown in FIG. 2 is a cross-sectional view, but the sealing material 16 and the fuel cell 3 are not hatched.

  The sealing material 16 has a concave meniscus surface exposed to the gas drifting outside the manifold 7 in a cross-sectional view in the arrangement direction of the fuel cells 3 and in the longitudinal direction of the fuel cells 3. A bottom portion 17 is provided near the central portion between them, and a concave outer shape that rises from the bottom portion 17 toward the fuel cell 3 is provided.

  Here, the fuel cell 3 and the sealing material 16 undergo volume changes due to temperature changes. In particular, if the difference between the thermal expansion coefficients of the fuel cell 3 and the sealing material 16 is large, an excessive stress is generated at the joint between the fuel cell 3 and the sealing material 16, and a crack is generated in the sealing material 16 near the joint. There was a fear. As a result, the fuel gas in the manifold 7 may leak and reliability may be reduced.

In particular, the inside of the manifold 7 is accompanied by a large temperature change due to repeated start and stop of the fuel cell device. That is, the stress applied to the joint between the fuel cell 3 and the sealing material 16 is particularly large on the manifold side.

  Therefore, the sealing material 16 according to the present embodiment has a thermal expansion coefficient of the sealing material 16 larger than the thermal expansion coefficient of the cell, the outer region 16b located outside the manifold 7 in the longitudinal direction of the fuel cell 3, and the fuel An inner region 16a positioned inside the manifold 7 in the longitudinal direction of the battery cell 3, and the difference in thermal expansion coefficient between the inner region 16a and the fuel cell 3 is the heat between the outer region 16b and the fuel cell 3. It is smaller than the difference in expansion coefficient.

  Thereby, the stress concerning the junction part of the fuel cell 3 and the sealing material 16 can be reduced, and generation | occurrence | production of a crack can be suppressed. As a result, the leakage of the fuel gas in the manifold 7 can be suppressed and the reliability can be improved.

  Incidentally, by making the thermal expansion coefficient of the outer region 16b relatively high, a compressive stress can be applied to the boundary between the fuel cell 3 and the outer region 16b. It is possible to suppress cracks due to peeling due to deformation at.

  Here, the inner region 16a of the sealing material 16 is a region located on the side exposed to the gas (fuel gas in the present embodiment) in the manifold 7 in the sealing material between the fuel cells 3 (in FIG. 2). The outer region 16b is a region located on the side exposed to the gas outside the manifold 7 (oxygen-containing gas in this embodiment) in the sealing material between the fuel cells 3. 2). Here, the inner region 16a and the outer region 16b are the lowermost of three division lines (two-dot chain lines in FIG. 2) that equally divide the length from the lower end 18a to the upper end 18b of the sealing material 16 in FIG. What is necessary is just to partition on the 18a side line (line C in FIG. 2). In other words, up to ¼ of the height of the sealing material 16 is the inner region 16a, and the upper side of the inner region 16a is the outer region 16b.

  “The thermal expansion coefficient of the sealing material is larger than the thermal expansion coefficient of the cell” means that the thermal expansion coefficient of the entire inner region 16 a and the entire outer region 16 b of the sealing material 16 is larger than the thermal expansion coefficient of the entire fuel cell 3. means.

The comparative evaluation of the thermal expansion coefficients of the inner region 16a and the outer region 16b of the sealing material 16 can be performed by the following method. First, a total of three arbitrary measurement areas of 100 μm ² are extracted for each area. Next, composition analysis of the extracted measurement region is performed by WDS or the like, and the composition ratio and crystal phase of the specific region are specified. Next, a sample having the composition ratio and the crystal phase is prepared, and the thermal expansion coefficient is measured. Finally, the average of the thermal expansion coefficients in the three extracted measurement regions is calculated, and the thermal expansion coefficients of the inner region 16a and the outer region 16b are compared.

  FIG. 3 is an enlarged view of a portion indicated by a broken line B in FIG. 2, and an inner region 16a of the sealing material 16 in FIG. 3 has a first region T1.

Further, the sealing member 16 and contains _Al 2 _{O 3,} the inner area 16a, the semi-quantitative mapping of EPMA analysis of _Al 2 _{O 3,} molar concentration of _Al 2 _{O 3} is in the outer region 16b of the sealing member 16 Including the first region T1 where measurement points that are twice or more the average molar concentration of Al ₂ O ₃ are concentrated, the area of the first region T1 is 100 μm ² or more, and the thermal expansion coefficient of the first region T1 is It may be a value equal to or lower than the thermal expansion coefficient of the fuel cell 3.

That is, by having the first region T1 whose thermal expansion coefficient is smaller than that of the fuel cell 3 in the inner region 16a, the thermal expansion coefficient of the inner region 16a can be reduced, and the fuel cell 3 and the inner region 16a can be reduced. The difference in thermal expansion can be further reduced. Therefore, the stress applied to the joint portion between the fuel cell 3 and the sealing material 16 can be reduced, and the generation of cracks can be suppressed.

Further, the area of the first region T1 of the inner region 16a may be 1000 μm ² or more. With this configuration, it is possible to reduce the stress applied to the joint between the fuel cell 3 and the sealing material 16 and further suppress the occurrence of cracks.

Further, instead of the first region T1 which measurement points molar concentration of _Al 2 _{O 3} is at least 2 times the average molar concentration of _Al 2 _{O 3} in the outer region 16b of the sealing member 16 is gathered, the molar concentration of SiO ₂ May have a second region in which measurement points that are twice or more the average molar concentration of SiO ₂ in the outer region of the sealing material are concentrated.

  With this configuration, since the inner region 16a has a second region (not shown) having a smaller thermal expansion coefficient than the fuel cell 3, the thermal expansion coefficient of the inner region 16a can be reduced. 3 and the inner region 16a can be further reduced. Therefore, the stress applied to the joint portion between the fuel cell 3 and the sealing material 16 can be reduced, and the generation of cracks can be suppressed.

Further, the second region of the inner region 16a may have an area of 1000 μm ² or more. With this configuration, it is possible to reduce the stress applied to the joint between the fuel cell 3 and the sealing material 16 and further suppress the occurrence of cracks.

  It is assumed that the first region T1 and the second region exist only in the inner region 16a of the sealing material 16. Further, both the first region T1 and the second region may exist in the inner region 16a of the sealing material 16. Furthermore, you may have the area | region where 1st area | region T1 and 2nd area | region overlap.

In addition, in detecting the 1st area | region T1 and 2nd area | region of 100 micrometers ² or more, it can detect by the semi-quantitative mapping of EPMA analysis, for example using JEOL X-ray microanalyzer JXA-8530F. At this time, the acceleration voltage is 15.0 (kV), the irradiation current is 1.012 × 10 ⁻⁷ (A), the time is 10 (ms), the number of measurement points is 250 (x axis) × 200 (y axis), and The measurement interval may be 0.5 μm (x axis) × 0.5 μm (y axis).

In detecting the first region T1 and the second region of 1000 μm ² or more, for example, can be detected by semi-quantitative mapping of EPMA analysis using JEOL X-ray microanalyzer JXA-8530F. At this time, the acceleration voltage is 15.0 (kV), the irradiation current is 1.007 × 10 ⁻⁷ (A), the time is 10 (ms), the number of measurement points is 310 (x axis) × 240 (y axis), and The measurement interval may be 10 μm (x axis) × 10 μm (y axis).

  “Measurement point” refers to one measurement point of the X-ray microanalyzer. The “area of the first region T1” or the “area of the second region” refers to the area of one first region T1 or the second region.

The thermal expansion coefficients of the first region T1 and the second region can be measured, for example, by the following method. First, the first region T1 and the second region are determined by semi-quantitative mapping of Al ₂ O ₃ or SiO ₂ EPMA analysis in the cross section of the inner region 16a of the sealing material 16 in the arrangement direction of the fuel cells 3 and in the longitudinal direction of the fuel cells 3. At least one of the two areas is specified (hereinafter referred to as a specific area). Next, the composition analysis of the specific region is performed by WDS or the like, and the composition ratio and crystal phase of the specific region are specified. Finally, a sample having the composition ratio and crystal phase is prepared, and the thermal expansion coefficient is measured.

  In addition to the method described above, the following method may be adopted as a method for performing the comparative evaluation of the thermal expansion coefficients of the inner region 16a and the outer region 16b. In the embodiment having the first region T1 or the second region, when the thermal expansion coefficient of the first region T1 or the second region is measured by the above-described method and the thermal expansion coefficient is smaller than the thermal expansion coefficient of the sealing material 16. It can be compared and evaluated that the thermal expansion coefficient of the inner region 16a is smaller than the thermal expansion coefficient of the outer region 16b. The thermal expansion coefficient of the sealing material 16 may be estimated from the composition of the sealing material 16 described above.

  The thermal expansion coefficient of the fuel cell 3 is cut out from the end of the fuel cell 3 that is fixed by the sealing material 16 to produce a measurement sample, and the thermal expansion coefficient is measured by a linear expansion coefficient measuring device (TMA). It can calculate by measuring using.

  The above-described cell stack apparatus can be manufactured by the following manufacturing method, for example. First, the frame body 7a is placed on the heat insulating plate-like body. Next, the lower end of the fuel cell 3 is inserted into the frame body 7a and placed on the plate-like body. Next, a material having a composition constituting the first region T1 (hereinafter referred to as a first additive) or a material having a composition constituting the second region (hereinafter referred to as a second additive) is formed into a plate-like body. Place on top. Next, a paste formed by adding an organic component to the Si-based crystallized glass powder is poured into the opening of the frame body 7a and heat-treated at 850 ° C. for 5 hours, and the lower end of the fuel cell 3 and the frame body 7a sealing material 16 are subjected to heat treatment. Secure with. Next, the plate-like body is pulled away from the frame body 7a or the lid-like member. Finally, the frame 7a to which the cell stack 2 is fixed is fixed to the gas tank 7a with a sealing material so as to close the opening on the upper surface of the gas tank 7b.

  Furthermore, in a cross-sectional view in the arrangement direction of the fuel cells 3 and in the longitudinal direction of the fuel cells 3, the inner surface of the inner region 16a is recessed toward the center of the sealing material 16 in the longitudinal direction of the fuel cells 3. It may be a shape.

  With this configuration, since the meniscus shape can relieve stress, it is possible to further suppress the occurrence of cracks in the vicinity of the joint portion between the fuel cell 3 and the inner region 16a of the sealing material 16.

  The meniscus shape of the inner region 16a in the sealing material 16 can be obtained by manufacturing the plate-like body having a convex portion corresponding to the concave meniscus shape on the plane by the method described above.

  4 is an external perspective view showing an example of a fuel cell module (hereinafter sometimes referred to as a module) provided with the cell stack device 1 of the present embodiment, and FIG. 5 is a cross-sectional view of FIG.

  In the module 20 shown in FIG. 4, the cell stack device 1 of the present embodiment is stored in the storage container 21. A reformer 22 for generating fuel gas to be supplied to the fuel cell 3 is disposed above the cell stack device 1. FIG. 4 shows the case where the cell stack apparatus 1 includes two cell stacks 2, but the number can be changed as appropriate. For example, even if only one cell stack 2 is provided. Good. Further, the cell stack apparatus 1 may include the reformer 22.

  In FIG. 4, the fuel cell 3 is a hollow flat plate type having a plurality of fuel gas passages through which fuel gas flows in the longitudinal direction, and a fuel electrode layer is formed on the surface of the support having the fuel gas passages. 1 illustrates a solid oxide fuel cell 3 in which a solid electrolyte layer and an oxygen electrode layer are sequentially laminated. An oxygen-containing gas flows between the fuel cells 3.

  In the reformer 22 shown in FIG. 4, raw gas such as natural gas or kerosene supplied via the raw fuel supply pipe 26 is reformed to generate fuel gas. The reformer 22 preferably has a structure capable of performing steam reforming, which is an efficient reforming reaction. The reformer 22 reforms the raw fuel into fuel gas, and a vaporizer 23 for vaporizing water. And a reforming section 24 in which a reforming catalyst (not shown) is disposed. The fuel gas generated by the reformer 22 is supplied to the manifold 7 through a fuel gas distribution pipe 25 (corresponding to the fuel gas supply pipe 8 shown in FIG. 1), and the interior of the fuel cell 3 is supplied from the manifold 7. Is supplied to the fuel gas flow path provided in the.

  Further, FIG. 4 shows a state in which a part (front and rear surfaces) of the storage container 21 is removed and the cell stack device 1 stored inside is taken out rearward. Here, in the module 20 shown in FIG. 4, the cell stack device 1 can be slid and stored in the storage container 21.

  Note that, inside the storage container 21, oxygen is disposed between the cell stacks 2 juxtaposed on the manifold 7, so that the oxygen-containing gas flows from the lower end portion toward the upper end portion of the fuel cell 3. A contained gas introduction member 27 is disposed.

  As shown in FIG. 5, the storage container 21 constituting the module 20 has a double structure having an inner wall 28 and an outer wall 29, and an outer frame of the storage container 21 is formed by the outer wall 29, and a cell stack is formed by the inner wall 28. A power generation chamber 30 that houses the device 1 is formed. Further, in the storage container 21, an oxygen-containing gas flow path 36 through which the oxygen-containing gas introduced into the fuel cell 3 circulates between the inner wall 28 and the outer wall 29.

  Here, the storage container 21 is provided with an oxygen-containing gas inlet (not shown) for allowing oxygen-containing gas to flow into the upper end side from the upper portion of the storage container 21 and a flange portion 40, and a fuel at the lower end portion. An oxygen-containing gas introduction member 27 provided with an oxygen-containing gas outlet 31 for introducing an oxygen-containing gas at the lower end of the battery cell 3 is inserted through the inner wall 28 and fixed.

  In FIG. 5, the oxygen-containing gas introduction member 27 is arranged so as to be positioned between two cell stacks 2 juxtaposed inside the storage container 21, but is appropriately arranged depending on the number of cell stacks 2. can do.

  Further, in the power generation chamber 30, the temperature in the module 20 is maintained at a high temperature so that the heat in the module 20 is extremely dissipated and the temperature of the fuel cell 3 (cell stack 2) is lowered and the power generation amount is not reduced. A heat insulating member 32 is provided as appropriate.

  The heat insulating member 32 is preferably disposed in the vicinity of the cell stack 2. In particular, the heat insulating member 32 is disposed on the side of the cell stack 2 along the arrangement direction of the fuel cells 3, and the fuel cell on the side of the cell stack 2. It is preferable to arrange the heat insulating member 32 having a width equal to or greater than the width along the three arrangement directions.

  Further, an exhaust gas inner wall 34 is provided on the inner side of the inner wall 28 along the arrangement direction of the fuel cells 3, and the exhaust gas in the power generation chamber 30 extends from above between the inner wall 28 and the exhaust gas inner wall 34. The exhaust gas flow path 37 flows downward. The exhaust gas passage 37 communicates with an exhaust hole 35 provided at the bottom of the storage container 21. Further, a heat insulating member 32 is also provided on the cell stack 2 side of the exhaust gas inner wall 34.

  As a result, the exhaust gas generated during the operation of the module 20 (during start-up processing, power generation, and stop processing) flows through the exhaust gas passage 37 and is then exhausted from the exhaust hole 35.

  Further, in the module 20 having the above-described configuration, the fuel gas and the oxygen-containing gas that have not been used for power generation discharged from the fuel gas flow path in the fuel cell 3 are transferred to the upper end of the fuel cell 3 and the reformer 22. It is possible to raise and maintain the temperature of the fuel cell 3 by burning between the two. In addition, the reformer 22 disposed above the fuel cell 3 (cell stack 2) can be warmed, and the reformer 22 can efficiently perform the reforming reaction. During normal power generation, the temperature in the module 20 is about 500 to 800 ° C. with the combustion and power generation of the fuel cell 3.

  FIG. 6 is an exploded perspective view showing an example of the fuel cell device of the present embodiment in which the module 20 shown in FIG. 4 and an auxiliary machine (not shown) for operating the module 20 are housed in an outer case. FIG. In FIG. 6, a part of the configuration is omitted.

  The fuel cell device 41 shown in FIG. 6 divides the interior of the exterior case composed of the columns 42 and the exterior plate 43 into upper and lower portions by the partition plate 44, and the upper side serves as a module storage chamber 45 for storing the module 20 described above. The lower side is configured as an auxiliary equipment storage chamber 46 for storing auxiliary equipment for operating the module 20. In addition, the auxiliary machine stored in the auxiliary machine storage chamber 46 is omitted.

  In addition, the partition plate 44 is provided with an air circulation port 47 for allowing the air in the auxiliary machine storage chamber 46 to flow toward the module storage chamber 45, and a part of the exterior plate 43 constituting the module storage chamber 45 includes An exhaust port 48 for exhausting air in the module storage chamber 45 is provided.

  In such a fuel cell device 41, as described above, the module 20 with improved long-term reliability is stored in the module storage chamber 45, and the auxiliary machine for operating the module 20 is stored in the auxiliary machine storage chamber 46. Thus, the fuel cell device 41 with improved long-term reliability can be obtained.

  Although the present invention has been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and improvements can be made without departing from the scope of the present invention.

  For example, a fuel battery cell in which an air electrode layer, a solid electrolyte layer, and a fuel electrode layer are disposed on a conductive support may be used. Further, for example, in the above embodiment, the fuel electrode layer 9, the solid electrolyte layer 10, and the air electrode layer 11 are laminated on the conductive support 13, but the fuel electrode layer 9 itself is not used without using the conductive support 13. A solid electrolyte layer 10 and an air electrode layer 11 may be provided on the fuel electrode layer 9 as a support.

  Further, the present invention can be applied to a horizontally-striped bundle formed by combining a plurality of so-called horizontally-striped fuel cell stacks in which a plurality of power generation element portions having an air electrode layer, a solid electrolyte layer, and a fuel electrode layer are formed on a support. it can.

Furthermore, although the fuel cell 3, the cell stack device 1, the module 20, and the fuel cell device 41 have been described in the above embodiment, hydrogen and water are obtained by electrolyzing water vapor (water) by applying water vapor and voltage to the cell. The present invention can also be applied to an electrolysis cell (SOEC) that generates oxygen (O ₂ ), an electrolysis cell stack device including the electrolysis cell, an electrolysis module, and an electrolysis device that is a module housing device.

(Sample preparation)
As shown in Table 1, seven samples were prepared for the cell stack apparatus described above.

  By the method described above, the cell stack was fixed to the frame with the sealing material having the first region in the inner region.

  Each sample of the cell stack apparatus includes 10 fuel cells. The shape of the fuel cell used in each sample was the same plate shape as in FIGS. The length of the fuel cell was 20 cm, the length of the fuel cell in the width direction was 20 mm, and the thickness was 2 mm. The thermal expansion coefficient of the fuel cell was about 10.9 ppm / K (the thermal expansion coefficient from room temperature to 1000 ° C.).

As the sealing material, a SiO ₂ —MgO—B ₂ O ₃ —Al ₂ O ₃ —CaO system was used. The composition ratio (molar concentration ratio) of the main components was 15 (SiO ₂ ): 21 (MgO): 26 (B ₂ O ₃ ): 5 (Al ₂ O ₃ ): 29 (CaO). The thermal expansion coefficient of the sealing material was about 11.6 ppm / K (the thermal expansion coefficient from room temperature to 1000 ° C.). The SiO ₂ —MgO—B ₂ O ₃ —Al ₂ O ₃ —CaO system was used as the first additive serving as the first region. Samples having different composition ratios (molar concentration ratios) of the first additive were prepared.

(Durability test)
Hydrogen gas is allowed to flow through the gas passage of the fuel cell of the cell stack device, and air is further allowed to flow outside the fuel cell (outer surface of the oxygen electrode layer) to generate power at 850 ° C. for 24 hours, and then the hydrogen gas is stopped. And allowed to cool naturally. The test was stopped every time the procedure was repeated a predetermined number of times (40 times, 60 times), and the presence or absence of cracks was confirmed. The results are shown in Table 1.

  In addition, the subsequent test was not performed about the stack apparatus which has cracked at the time of confirmation.

The test results are shown in Table 1. In Table 1, the composition ratio (molar concentration ratio) of the first additive serving as the first region and the composition ratio (molar concentration ratio) of Al ₂ O ₃ contained in the first additive are included in the sealing material. Al ₂ composition ratio of O ₃ (molar ratio) concentration ratio of Al ₂ O ₃ is divided by the value of the thermal expansion coefficient of the first additive, the outer region (Table 1 of the fuel cell and the sealing material The relationship of the thermal expansion coefficient between the outer region and the inner region of the sealing material (abbreviated as inner side in Table 1) and the number of cycles of the thermal cycle test are described.

(Durability test results)
Sample No. In Nos. 1 and 3, cracks occurred in the inner region of the sealing material after 40 thermal cycle tests. This is because the thermal expansion coefficient of the inner region of the sealing material is equal to or greater than the thermal expansion coefficient of the outer region, and the difference between the thermal expansion coefficient of the fuel cell and the thermal expansion coefficient of the inner region is large.

  In Samples Nos. 2 and 4 to 7, no cracks occurred in the inner region of the sealing material after 40 thermal cycle tests. This is because the inner region of the sealing material has a smaller thermal expansion coefficient than the outer region, and the difference between the thermal expansion coefficient of the fuel cell and the thermal expansion coefficient of the inner region is small.

  Sample No. In Nos. 2, 4, and 5, cracks occurred in the inner region of the sealing material after 60 thermal cycle tests. In Nos. 6 and 7, no cracks occurred in the inner region of the sealing material. This is the sample No. The thermal expansion coefficient of the inner region of the sealing material in Samples 6 and 7 is Sample No. This is because the difference between the thermal expansion coefficient of the fuel battery cell and the thermal expansion coefficient of the inner region is further smaller than that of 5.

(Sample preparation)
About the cell stack apparatus mentioned above, as shown in Table 2, five samples were produced.

  By the method described above, the cell stack was fixed to the frame with the sealing material having the first region in the inner region.

  Conditions other than the maximum particle cross-sectional area of the first additive serving as the first region are the sample Nos. It was the same as 7. Samples having different maximum particle cross-sectional areas of the first additive were prepared.

The “maximum particle cross-sectional area” corresponds to the area of the first region recognized in the semi-quantitative mapping of the EP ₂ analysis of Al ₂ O ₃ .

(Durability test)
The test method was the same as Example 1 except that the number of repetitions was 70.

(Durability test results)
The test results are shown in Table 2.

  Sample No. 1 to 3, cracks occurred in the inner region of the sealing material after 70 thermal cycle tests.

On the other hand, sample No. 1 in which the area of the first region contained in the inner region (maximum particle cross-sectional area of the first additive) is 1000 μm ² or more. In Nos. 4 and 5, no cracks occurred in the inner region of the sealing material after 70 thermal cycle tests.

(Sample preparation)
About the cell stack apparatus mentioned above, as shown in Table 3, five samples were produced.

  By the method described above, the cell stack was fixed to the frame with the sealing material having the second region in the inner region.

  Conditions other than the composition ratio (molar concentration ratio) of the second additive serving as the second region were the same as in Example 1. Samples having different composition ratios (molar concentration ratios) of the second additive were prepared.

(Durability test)
The test method was the same as in Example 1.

The test results are shown in Table 3. In Table 3, the composition ratio of the second additive material comprising a second region (molar ratio), SiO ₂ contained the composition ratio of SiO ₂ (molar concentration ratio) in the sealing material contained in the second additive The concentration ratio of SiO ₂ , which is a value divided by the composition ratio (molar concentration ratio), the value of the thermal expansion coefficient of the first additive, and the outer region of the fuel cell and the sealing material (abbreviated as “outside” in Table 3). The relationship of the thermal expansion coefficient with the inner region of the sealing material (abbreviated as inner side in Table 3) and the number of cycles of the thermal cycle test are described.

(Durability test results)
Sample No. In No. 1, cracks occurred in the inner region of the sealing material after 40 thermal cycle tests. This is because the inner region of the sealing material has a larger thermal expansion coefficient than the outer region, and the difference between the thermal expansion coefficient of the fuel cell and the thermal expansion coefficient of the inner region is large.

  In Samples Nos. 2 to 5, no cracks occurred in the inner region of the sealing material after 40 thermal cycle tests. This is because the inner region of the sealing material has a smaller thermal expansion coefficient than the outer region, and the difference between the thermal expansion coefficient of the fuel cell and the thermal expansion coefficient of the inner region is small.

  Sample No. 2, cracks occurred in the inner region of the sealing material after 60 thermal cycle tests. In 3-5, the crack did not generate | occur | produce in the inner side area | region of the sealing material. This is the sample No. The thermal expansion coefficient of the inner region of the sealing material in 3 to 5 is the sample No. This is because the difference between the thermal expansion coefficient of the fuel cell and the thermal expansion coefficient of the inner region is further smaller than that of 2.

(Sample preparation)
About the cell stack apparatus mentioned above, as shown in Table 4, five samples were produced.

  By the method described above, the cell stack was fixed to the frame with the sealing material having the second region in the inner region.

  Conditions other than the maximum particle cross-sectional area of the second additive in the second region are the sample Nos. In Table 3 in Example 3. It was the same as 4. Samples having different maximum particle cross-sectional areas of the second additive were prepared.

The “maximum particle cross-sectional area” corresponds to the area of the second region recognized in the semi-quantitative mapping of the EP ₂ analysis of SiO ₂ .

(Durability test)
The test method was the same as Example 1 except that the number of repetitions was 70.

(Durability test results)
The test results are shown in Table 4.

  Sample No. 1 to 3, cracks occurred in the inner region of the sealing material after 70 thermal cycle tests.

On the other hand, sample No. ² in which the area of the second region contained in the inner region (maximum particle cross-sectional area of the second additive) is 1000 μm ² or more. In Nos. 4 and 5, no cracks occurred in the inner region of the sealing material after 70 thermal cycle tests.

1: Cell stack device 3: Fuel cell 7: Manifold 16: Sealing material 16a: Inner region 16b: Outer region 20: Fuel cell module 41: Fuel cell device

Claims (8)

A cell stack in which a plurality of columnar cells are arranged;
A manifold for supplying reaction gas to the plurality of cells;
A sealing material made of glass for fixing one end of the plurality of cells to the manifold;
The thermal expansion coefficient of the sealing material is larger than the thermal expansion coefficient of the cell,
An outer region located outside the manifold in the longitudinal direction of the cell;
An inner region located inside the manifold in the longitudinal direction of the cell,
The cell stack device, wherein a difference in thermal expansion coefficient between the inner region and the cell is smaller than a difference in thermal expansion coefficient between the outer region and the cell. The sealing material contains Al ₂ O ₃ ,
Said inner region, the semi-quantitative mapping of EPMA analysis of _Al 2 _{O 3,} more than double that measurement points of the average molar concentrations of _Al 2 _{O 3} molar of _Al 2 _{O 3} is in the outer region of the sealing material gathered Including the first area
^2. The cell stack device according to claim 1, wherein the area of the first region is 100 μm ² or more, and the thermal expansion coefficient of the first region is not more than the thermal expansion coefficient of the cell. The cell stack device according to claim 2, wherein an area of the first region is 1000 μm ² or more. The sealing material is contained SiO _2,
In the semi-quantitative mapping of the SiO ₂ EPMA analysis, the inner region includes a _second region in which measurement points where the molar concentration of SiO ₂ is at least twice the average molar concentration of SiO ₂ in the outer region of the sealing material are gathered. ,
^2. The cell stack device according to claim 1, wherein the area of the second region is 100 μm ² or more, and the thermal expansion coefficient of the second region is not more than the thermal expansion coefficient of the cell. The cell stack device according to claim 4, wherein an area of the second region is 1000 μm ² or more. The inner surface of the inner region has a meniscus shape that is recessed toward the center of the sealing material in the longitudinal direction of the cell in a cross-sectional view in the cell arrangement direction and in the longitudinal direction of the cell. The cell stack device according to claim 1.   A fuel cell module comprising the cell stack device according to claim 1 stored in a storage container.   8. A fuel cell device comprising: the fuel cell module according to claim 7; and an auxiliary machine for operating the fuel cell module, housed in an outer case.

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