JP6452516B2 - Separator for solid oxide fuel cell and solid oxide fuel cell - Google Patents

Description

  The present invention relates to a solid oxide fuel cell separator and a solid oxide fuel cell, and more specifically, a separator having a gas flow path disposed outside an electrode of a solid oxide fuel cell, and The present invention relates to a solid oxide fuel cell configured to be used.

  A solid oxide fuel cell (SOFC) is basically composed of a single cell in which a fuel electrode (anode) and an air electrode (cathode) are bonded to both surfaces of a solid electrolyte layer. In SOFC, a power generation device is often formed by forming a stack structure in which a plurality of single cells are electrically connected in series via a separator in which a gas flow path is formed in a plate-like metal member.

  This type of SOFC is assembled by laminating constituent members such as a single cell and sandwiching them between plate-like separators through a sealing material such as a glass seal as appropriate. The sealant functions as an adhesive that joins the members, and prevents the fuel gas supplied to the fuel electrode and the air supplied to the air electrode from intermixing and leaking to the outside in the assembled SOFC. To play a role. FIG. 7 shows an example of a conventional general SOFC unit in which a constituent member such as a single cell is sandwiched between plate-like separators via a sealing material.

  A conventional solid oxide fuel cell (SOFC) unit 100 shown in FIG. 7 includes an air electrode side separator 110, a thin film separator 112, a fuel electrode side separator 120, a single cell 130, current collectors 140 and 145, and an insulating frame 150. It is comprised as a main member. The air electrode side separator 110 and the fuel electrode side separator 120 have a gas flow path formed in a plate-shaped metal material. The thin film separator 112 is a member made of a thin metal plate provided in contact with the air electrode side separator 110, and plays a role in reducing the difference in thermal expansion between the air electrode side separator 110 and the single cell 130. .

  As shown in FIG. 7A, the SOFC unit 100 is provided with paste-like sealing materials 161a, 161b, 162 such as glass seals on both surfaces of the insulating frame 150 and portions of the thin film separator 112 facing the single cell 130. After the application, the members are assembled as shown in FIG. 7B, and the seal materials 161a, 161b, 162 are cured in a state where a load is applied. As described above, for example, Patent Document 1 discloses an SOFC unit formed by sandwiching a structural member between plate-like separators with a sealing material interposed therebetween.

JP 2014-49321 A

  As described above with reference to FIG. 7, a member such as the single cell 130 is stacked and sandwiched between the plate-like separators 110 and 120 via the sealing materials 161 a, 161 b, and 162, and the SOFC. When assembling the unit 100, it is required to position each member in the in-plane direction and the thickness direction with high accuracy. Moreover, it is necessary to form the layers of the sealing materials 161a, 161b, 162 in a uniform thickness in accordance with the thickness of each member. For that purpose, it is necessary to apply the sealant paste uniformly and to apply a load uniformly to cure. If there is non-uniformity in the thickness of the sealing materials 161a, 161b, 162, an incomplete seal may occur, and gas may be mixed inside the SOFC unit 100 or leaked to the outside. There is sex. As described above, in the method of assembling the SOFC unit 100 by stacking and sandwiching the respective members between the plate-like separators 110 and 120, a high assembling technique is required in order to obtain the SOFC unit 100 having high gas sealability. It becomes. In particular, when a cell stack is configured by stacking a large number of SOFC units 100 as shown in FIG. 7, a member such as a single cell 130 and sealing materials 161a and 161b are formed in each space formed between a large number of separators. , 162 and positioning and gas seal establishment for all SOFC units 100 must be performed simultaneously. Under such circumstances, it is very difficult to obtain a high gas sealability in the entire cell stack.

  Further, when performance is confirmed for a cell stack formed by stacking a large number of SOFC units 100, the presence or absence of defective SOFC units 100 is confirmed unless all the stacked SOFC units 100 are activated at once. I can't. Further, even when a defective SOFC unit 100 is discovered in this way, it is not possible to remove only the SOFC cell 100 from the stack structure and replace it. Therefore, in order to obtain a cell stack that exhibits desired characteristics, a very high yield is required for the performance of each SOFC cell 100.

  The problem to be solved by the present invention is to provide a separator capable of easily constructing a solid oxide fuel cell having high gas-sealability, and to provide such a separator and to easily obtain high gas-seal properties. An object of the present invention is to provide a solid oxide fuel cell.

  In order to solve the above problems, a solid oxide fuel cell separator according to the present invention is a separator used together with a solid oxide fuel cell single cell having a fuel electrode and an air electrode on both sides of a flat electrolyte layer. The solid oxide fuel cell formed by surrounding the outer periphery of the first contact surface above the first contact surface, the first contact surface having a first flow path through which gas can flow. The gist is to integrally have a frame-like placement surface on which a single cell can be placed, and a frame-like frame surface formed around the outer periphery of the placement surface above the placement surface. And

  Here, the separator for the solid oxide fuel cell is provided on the back side of the first contact surface, the mounting surface, and the frame surface, and a second contact surface in which a second flow path through which gas can flow is formed. And a gas supply hole penetrating between the frame surface and the second contact surface and communicating with the first flow path.

  In this case, the first channel and the second channel may be running in the same direction.

  The difference in height between the mounting surface and the frame surface is preferably equal to or greater than the thickness of the fuel electrode of the solid oxide fuel cell single cell.

  In order to solve the above problems, a solid oxide fuel cell according to the present invention includes a solid oxide fuel cell single cell having a fuel electrode and an air electrode on both sides of a flat electrolyte layer, and It is characterized by having a separator for a solid oxide fuel cell.

  Here, the solid oxide fuel cell has the solid oxide fuel cell separator as described above as a fuel electrode side separator, and is further disposed outside the air electrode of the solid oxide fuel cell single cell. The solid oxide fuel cell single cell has an air electrode side separator formed on the mounting surface of the fuel electrode side separator via an electrically insulating internal sealing material that blocks gas flow. Fuel on which fuel gas is circulated as a space placed on the fuel electrode side and surrounded by the solid oxide fuel cell single cell, the fuel electrode side separator, and the inner seal material and partitioned from the outside It is preferable that a gas circulation part is formed.

  In this case, a gap between the fuel electrode and the first contact surface of the fuel electrode side separator is made of a conductive material that is more easily elastically deformed than the solid oxide fuel cell single cell and the fuel electrode side separator. An electric material is preferably arranged.

  Alternatively, the fuel electrode may be in direct contact with the first contact surface of the fuel electrode side separator.

  Further, the air electrode side separator is joined to the frame surface of the fuel electrode side separator through at least an electrically insulating external sealing material arranged outside the fuel gas circulation part and blocking the gas flow. It is preferable that

  In this case, the air electrode side separator may be directly joined to the frame surface of the fuel electrode side separator via the external sealing material.

  Moreover, it is preferable that the frame surface of the fuel electrode side separator has a height equal to a boundary surface between the electrolyte layer and the air electrode of the solid oxide fuel cell single cell.

  The fuel-side separator is made of a solid oxide fuel cell separator having the second contact surface as described above, and a plurality of the solid oxide fuel cell single cells are used for the solid oxide fuel cell. The separator for a solid oxide fuel cell provided as the fuel electrode side separator of one solid oxide fuel cell single cell is stacked via a separator, and includes the second contact surface. The air electrode side separator of another solid oxide fuel cell unit cell adjacent to the solid oxide fuel cell unit cell may be configured.

  In this case, the stacked structure of the solid oxide fuel cell single cell and the solid oxide fuel cell separator is provided with an external manifold for supplying air, and the adjacent solid oxide fuel cell separator Air may be supplied from the external manifold to the second flow path via a gap between the two.

  In the separator for a solid oxide fuel cell according to the above-described invention, a mounting surface on which a solid oxide fuel cell single cell can be mounted is provided between the first contact surface and the frame surface. If a single cell is appropriately placed on the placement surface via a sealing material, the single cell is positioned in a state of being fitted between the placement surface and the frame surface. In this state, if other members arranged above the single cell are appropriately laminated via a sealing material and a solid oxide fuel cell is assembled, the single cell is fitted and held as in the conventional case. Compared to the assembly of a solid oxide fuel cell by sandwiching each member, such as a single cell, between two plate-shaped separators that do not have a mechanism to do so, the positional relationship of each member including the separator is specified Assembling can proceed in this state, so that positioning of each member in the in-plane direction and thickness direction and formation of a gas seal can be performed with high accuracy and simplicity. In addition, in the assembly process, it is possible to check whether there is a performance defect for each layer by performing a test run for each layer of each single cell, so that each single cell has a high yield in performance. Even if they do not have it, they can easily find defective products and take measures such as removal.

  Here, the solid oxide fuel cell separator is provided on the first contact surface, the mounting surface, and the back side of the frame surface, and the second contact surface in which a second flow path through which gas can flow is formed, and the frame A gas supply hole provided between the first surface and the second contact surface and in communication with the first flow path, the first contact surface and the second contact surface of the separator, It can be used as a contact surface for supplying gas to each of the fuel electrode and the air electrode. Therefore, a cell stack in which a plurality of units of solid oxide fuel cells are stacked can be configured by alternately stacking single cells and separators. At this time, since the placement surface is provided on the first contact surface side of the separator, the unit cell is placed on the placement surface, and after being fitted between the frame surface, each remaining By proceeding with the stacking of the members, positioning and gas seal formation can be performed easily and with high accuracy even when a large number of separators and single cells are stacked. Furthermore, since the gas supply holes as described above are provided in the separator, the gas supply holes of the stacked separators communicate with each other, and a gas seal is provided between the second contact surfaces. An internal manifold type gas supply path for supplying gas to one flow path can be easily constructed.

  In this case, if the first flow path and the second flow path run in the same direction, a cell stack of a parallel flow method can be formed when the cell stack is formed, but the separator as described above is used. As a result, the mixing of the two gases can be prevented to a high degree, so that a parallel flow method in which mixing of both gases is generally problematic can be easily realized.

  If the difference in height between the mounting surface and the frame surface is equal to or greater than the thickness of the fuel electrode of the solid oxide fuel cell single cell, the single cell is appropriately placed on the fuel electrode side via a sealing material. It is easy to form a state in which the entire fuel electrode is disposed in a region between the mounting surface and the frame surface. By doing so, when assembling the solid oxide fuel cell, the space in which the fuel gas supplied to the fuel electrode flows can be easily separated from the outside with high gas sealability.

  In the solid oxide fuel cell according to the above-described invention, the single cell is mounted on the mounting surface of the separator and assembled, thereby positioning the single cell and forming a gas seal with high accuracy and simplicity. Can do.

  Here, the solid oxide fuel cell has the above-described solid oxide fuel cell separator as a fuel electrode side separator, and is further disposed outside the air electrode of the solid oxide fuel cell single cell. The solid oxide fuel cell unit cell has an air electrode side separator, and the surface of the fuel electrode side is disposed on the surface of the fuel electrode side separator through an electrically insulating internal sealing material that blocks gas flow. When the fuel gas circulation part through which the fuel gas is circulated is formed as a space that is placed and surrounded by the solid oxide fuel cell single cell, the fuel electrode side separator, and the inner seal material and partitioned from the outside Since the fuel gas circulation part is formed in a state where the single cell is fitted and positioned in the space between the mounting surface and the frame surface, the simple gas seal structure allows the fuel cell circulation part to be separated from the fuel gas circulation part. High fuel gas leakage It can be suppressed to. Further, after positioning and sealing between the single cell and the fuel electrode side separator with high accuracy in this way, another member can be laminated on the upper layer to assemble a solid oxide fuel cell. As a whole, the solid oxide fuel cell can be easily assembled and a highly reliable gas seal can be easily formed.

  In this case, a current collector made of a conductive material that is more elastically deformable than the solid oxide fuel cell single cell and the fuel electrode side separator is disposed between the fuel electrode and the first contact surface of the fuel electrode side separator. In some cases, the elastic deformation of the current collector is used to absorb dimensional errors and differences in thermal expansion between the single cell and the fuel electrode side separator, and the accuracy of positioning and seal formation between the fuel electrode side separator and the single cell. Can be improved.

  Alternatively, when the fuel electrode is in direct contact with the first contact surface of the fuel electrode-side separator, the number of members constituting the solid oxide fuel cell can be reduced by not using the current collector as described above. The assembly of the solid oxide fuel cell can be further simplified.

  Further, when the air electrode side separator is joined to the frame surface of the fuel electrode side separator through at least an electrically insulating external sealing material that is disposed outside the fuel gas circulation part and blocks the gas flow. In this case, since the sealing portion by the external sealing material does not come into contact with the fuel gas, even if a sealing failure occurs at this sealing portion, it does not lead to the leakage of the fuel gas and goes outside the solid oxide fuel cell. With respect to the leakage of the fuel gas, high sealing performance can be obtained.

  In this case, if the air electrode side separator is directly joined to the frame surface of the fuel electrode side separator via an external seal material, a frame-like insulating material, etc., between the fuel electrode side separator and the air electrode side separator, Since no member other than the sealing material is interposed, the number of members constituting the solid oxide fuel cell can be reduced, and the assembly of the solid oxide fuel cell can be further simplified.

  Also, if the frame surface of the fuel electrode side separator is flush with the boundary surface between the electrolyte layer of the solid oxide fuel cell single cell and the air electrode, the assembly of the solid oxide fuel cell is completed. Sometimes it is easy to form a gas seal and position each member in the thickness direction with high accuracy.

  The fuel-side separator comprises a solid oxide fuel cell separator having the second contact surface as described above, and a plurality of solid oxide fuel cell single cells are interposed via the solid oxide fuel cell separator. The solid oxide fuel cell separator provided as a fuel electrode side separator of one solid oxide fuel cell single cell is a portion including the second contact surface, and the solid oxide type When configuring the air electrode side separator of another solid oxide fuel cell unit cell adjacent to the fuel cell unit cell, a cell stack in which mixing of fuel gas with air and leakage to the outside is highly suppressed, It can be formed easily.

  In this case, an air supply external manifold is provided in the laminated structure of the solid oxide fuel cell single cell and the solid oxide fuel cell separator, and a gap between adjacent solid oxide fuel cell separators is provided. When air is supplied from the external manifold to the second flow path via the, a supply path for supplying air to the air electrode of each stacked solid oxide fuel cell single cell is constructed with a simple configuration. be able to.

It is a figure which shows the outline of the separator for solid oxide fuel cells concerning one Embodiment of this invention, (a) is a side view, (b) is a perspective view of an upper surface side, (c) is a perspective view of a back surface side. It is. 1 is a cross-sectional view schematically showing a solid oxide fuel cell according to a first embodiment of the present invention. (A) is the figure which shows the state which mounted the SOFC single cell in the separator, and is a figure which shows the arrangement | positioning location of the sealing material in the surface by the side of a fuel electrode, (b) is the arrangement | positioning location of the sealing material in the surface by the side of an air electrode FIG. It is sectional drawing which shows the cell stack which laminated | stacked multiple said solid oxide fuel cells. It is sectional drawing which shows the outline of the solid oxide fuel cell concerning 2nd embodiment of this invention. It is sectional drawing which shows the outline of the solid oxide fuel cell concerning 3rd embodiment of this invention. It is a figure which shows the cross section of the conventional general solid oxide fuel cell, (a) is before an assembly, (b) shows the state after an assembly.

  Hereinafter, a solid oxide fuel cell separator and a solid oxide fuel cell (SOFC) according to embodiments of the present invention will be described with reference to the drawings.

[Single oxide fuel cell single cell]
First, a SOFC single cell (hereinafter sometimes simply referred to as “single cell”) 30 that is used together with the SOFC separator according to the embodiment of the present invention and constitutes the SOFC according to the embodiment of the present invention will be briefly described. .

As shown in FIGS. 2 to 5, the single cell 30 is a main member of the SOFC that generates power by receiving supply of a fuel gas containing hydrogen and air (or a gas containing oxygen, the same applies hereinafter), It has a flat electrolyte layer 31 made of an oxide electrolyte, an air electrode 32 bonded to one surface of the electrolyte layer 31, and a fuel electrode 33 bonded to the other surface. The material constituting the electrolyte layer 31 and the electrodes 32 and 33 may be appropriately selected from materials used in known SOFCs. As the material of the electrolyte layer 31, a solid oxide electrolyte material exhibiting oxygen ion conductivity may be used, and examples thereof include stabilized zirconia (ZrO ₂ ) and ceria (CeO ₂ ) solid solutions, and composites of these with alumina. can do. Examples of the material of the air electrode 32 include La _1-x Sr _x MnO ₃ , La _1-x Ca _x MnO ₃ , La _1-x Sr _x CoO ₃ , La _1-x Sr _x Co _1-y Fe _y O ₃ , Examples of the material of the fuel electrode 33 that can be exemplified by transition metal perovskite complex oxides such as Pr _1-x Sr _x MnO ₃ include Ni, Ni alloy, nickel oxide (NiO), Co, Ru, Pt, and Pd. A cermet formed from a catalyst such as the above and a solid electrolyte can be exemplified. An intermediate layer may be appropriately formed between the electrolyte layer 31 and the electrodes 32 and 33. In the single cell 30, both electrodes 32 and 33 are formed in a smaller area than the electrolyte layer 31, and the electrolyte layer 31 is exposed over the entire periphery at the peripheral portions of both surfaces of the single cell 30.

[Separators for solid oxide fuel cells]
Next, the SOFC separator 1 according to an embodiment of the present invention used with the single cell 30 as described above will be described. FIG. 1 shows the configuration of the separator 1.

  In the separator 1, a block-shaped metal member is integrally provided with a plurality of uneven structures. The separator 1 is made of a metal material having heat resistance such as stainless steel.

  A first contact surface 23, a mounting surface 22, and a frame surface 21 that are parallel to each other are formed in a stepped manner on one surface of the separator 1 in order from the thickness direction of the block material and the inside of the surface direction. In other words, the surface of the block material is the frame surface 21, and the bottom surface of the recess provided inside the frame surface 21 is the first contact surface 23. And the mounting surface 22 is formed in the middle part of the depth direction of a recessed part.

  In the first contact surface 23, a plurality of substantially parallel first ridges 23a are formed on a flat surface. And the flat surface pinched | interposed between the 1st protruding item | line 23a becomes the 1st flow path 23b through which gas can distribute | circulate.

  The mounting surface 22 has a frame shape with an opening at the center so as to surround the outer periphery of the first contact surface 23 above the top surface of the first protrusion 23a of the first contact surface 23 (outside in the thickness direction). Is formed. The mounting surface 22 has a shape capable of mounting the single cell 30 as described above. Specifically, as shown in FIG. 2 and the like, the outer edge 22a is slightly larger than the outer shape of the surface of the electrolyte layer 31 of the single cell 30, that is, when the SOFC is assembled using the single cell 30 and the separator 1. The outer shape of the surface of the electrolyte layer 31 is larger than that of the surface of the electrolyte layer 31 so that the placed single cell 30 can be held without displacement within the range of the dimensional error. And the inner edge 22b used as the circumference of an opening is larger than the surface of the fuel electrode 33, that is, when the single cell 30 is mounted on the mounting surface 22 by the surface on the fuel electrode 33 side, the entire surface of the fuel electrode 33 is It is formed so as to be disposed in the opening. Thereby, when the single cell 30 is placed on the placement surface 22 on the surface on the fuel electrode 33 side, the electrolyte layer 31 exposed on the outer peripheral portion of the fuel electrode 33 comes into contact with the placement surface 22, and the fuel electrode 33 is placed. Do not touch surface 22. The height difference d2 between the top surface of the first ridge 23a of the mounting surface 22 and the first contact surface 23 is an embodiment of the SOFC unit constructed using the separator 1 as will be described later. Accordingly, the fuel electrode side current collector 45 is disposed so that the surface of the fuel electrode 33 of the single cell 30 mounted on the mounting surface 22 is just in contact with the top surface of the first ridge 23a or not in contact therewith. It is appropriately selected so as to have a possible void.

  The frame surface 21 is formed in a frame shape having an opening at the center so as to surround the outer periphery of the mounting surface 22 above the mounting surface 22. The height difference d1 between the frame surface 21 and the mounting surface 22 may be appropriately determined according to the specific dimensions of the single cell 30, but is preferably equal to or greater than the thickness of the fuel electrode 33. Then, when the single cell 30 is placed on the placement surface 22 with the surface on the fuel electrode 33 side through the sealing material 62, the entire fuel electrode 33 is easily placed below the frame surface 21. More preferably, as shown in FIG. 2 and the like, when the single cell 30 is mounted on the mounting surface 22 with the surface on the fuel electrode 33 side through the sealing material, the surface of the electrolyte layer 31 on the surface on the air electrode 32 side. What is necessary is just to set the height difference d1 between the frame surface 21 and the mounting surface 22 so that the height is substantially flush with the frame surface 21.

  In the separator 1, the back side of the surface on which the first contact surface 23, the mounting surface 22, and the frame surface 21 are provided is a second surface in which the second protrusion 11 a is provided on a flat surface having the same outer shape as the frame surface 21. A contact surface 11 is formed. A flat surface sandwiched between the second ridges 11a is a second flow path 11b through which gas can flow. The first ridges 23a and the second ridges 11a, that is, the first flow path 23b and the second flow path 11b may run in the same direction (parallel), or may take other positional relationships such as vertical. In the example shown in FIG. 1, it runs in the same direction.

  Further, in the separator 1, a fuel supply hole 1 a is formed on the frame surface 21 as a through-hole provided between the second contact surface 11 on the back side. The fuel supply hole 1 a becomes a flow path through which the fuel gas supplied to the fuel electrode 33 of each single cell 30 passes when the cell stack is formed using the separator 1. Specifically, the fuel supply holes 1a are provided in pairs on two sides of the frame surface 21 that are substantially perpendicular to the first flow path 23b. The fuel supply hole 1a penetrates between the frame surface 21 and the second contact surface 11 in the thickness direction, and crosses the placement surface 22 from the edge of the opening on the frame surface 21, and the first contact surface 23 It has a groove-shaped notch 1c dug toward one flow path 23b. Thus, even when a flat surface such as another separator or an insulating frame is in close contact with the frame surface 21, the space in the fuel supply hole 1a communicates with the first flow path 23b through the notch 1c. Maintained. The separator 1 has such a fuel supply hole 1a in the frame surface 21, so that, as will be described later, when a plurality of layers are stacked together with the SOFC single cells 30 using an appropriate sealing material, each of the fuel gas is supplied by an internal manifold system. While supplying to the fuel electrode 33 of the single cell 30, the cell stack which supplies the air electrode 32 of each single cell by an external manifold system can be constructed | assembled simply.

[Solid oxide fuel cell]
Next, SOFCs according to three types of embodiments of the present invention formed using the separator 1 and the single cell 30 as described above will be described.

(1) First Embodiment FIG. 2 shows a schematic cross-sectional view of an SOFC unit 2A constituting an SOFC according to a first embodiment of the present invention. As shown in FIG. 3, the present SOFC unit 2 </ b> A constitutes an SOFC in the state of a plurality of stacked cell stacks 3. In the cell stack 3, a plurality of SOFC units 2A are connected in series with the separator 1 described above as a boundary. In FIG. 2, the part surrounded by the broken line in FIG. 3 is shown as one unit of the SOFC unit 2A. As described above, the separator 1 is a member integrally formed as a whole. However, in FIG. 2 and the following description, for convenience, the first contact surface 23 and the mounting surface 22 of the separator 1 are included. The surface on which the frame surface 21 is provided is the fuel electrode side separator 20, and the portion on the side on which the second contact surface 11 is provided is the air electrode side separator 10, which is divided into upper and lower parts. A certain separator 1 functions as the fuel electrode side separator 20 of a certain single cell 30 at a portion on the side where the first contact surface 11 is provided, and a cell stack on the side where the second contact surface 23 is provided. Thus, the air electrode side separator 10 of another unit cell 30 adjacent to the unit cell 30 in the three stacked structures is formed.

  As shown in FIG. 2, the present SOFC unit 2A includes an air electrode side separator 10 and a fuel electrode side separator 20, and a single cell 30, an air electrode side current collector 40, and a fuel electrode side current collector 45 disposed therebetween. The insulating frame 50 is included as a constituent member. And it has the external sealing material 61 (61a-61e) and the internal sealing material 62 in the predetermined site | part between each member.

  The air electrode side current collector 40 is disposed between the air electrode 32 of the single cell 30 and the second contact surface 11 of the air electrode side separator 20, and the fuel electrode side current collector 45 includes the fuel electrode 33 of the single cell 30, It arrange | positions between the 1st contact surfaces 23 of the fuel electrode side separator 20. FIG. The current collectors 40 and 45 provide a good electrical connection with low contact resistance between the electrodes 32 and 33 of the single cell 30 and the separators 10 and 20, and gas flow paths 11 b provided in the separators 10 and 20. From 23b, it plays the role which supplies air and fuel gas to each electrode 32 and 33 in a state with high spatial uniformity. The fuel electrode side current collector 45 is a conductive material such as metal wool such as steel wool, metal foam, high porosity porous metal, etc., through which gas can pass, and has cushioning properties, that is, in the thickness direction. It is made of a material that is more easily elastically deformed than the fuel electrode-side separator 20 and the single cell 30 when a load is applied thereto. On the other hand, the air electrode side current collector 40 is made of a material that does not substantially have cushioning properties, such as a metal foil or a metal plate having many through holes, such as a mesh material or a metal wire net. The air electrode side current collector 40 and the fuel electrode side current collector 45 have substantially the same surface shapes as the air electrode 32 and the fuel electrode 33 of the single cell 30, respectively.

  The insulating frame 50 is made of an insulator having heat resistance, such as mica and other oxides, which does not cause deformation or alteration at the operating temperature (700 to 1000 ° C.) of the SOFC unit 2A. The insulating frame 50 has an opening that can accommodate the single cell 30 and the current collectors 40 and 45, and the frame surfaces 21 of the air electrode side separator 10 and the fuel electrode side separator 20 with these members being accommodated in the openings. It is arranged between. And it plays the role which prescribes | regulates the space | interval of both the separators 10 and 20, ensuring the insulation between both the separators 10 and 20. FIG. Although not shown in the drawing, in the insulating frame 50, fuel supply holes penetrating in the thickness direction are formed at positions corresponding to the fuel supply holes 1a of the separators 10 and 20 (not shown). When assembled, the fuel supply holes of the insulating frame 50 communicate linearly with the corresponding fuel supply holes 1a of the separators 10 and 20.

  The outer sealing material 61 and the inner sealing material 62 are made of an electrically insulating material that can block gas flow and maintain an airtight seal even at a high temperature (700 to 1000 ° C.) at which the SOFC unit 2A is operated. Yes. As a sealing material that can form such a seal and can be applied in the form of a paste, a known gas sealing material such as a glass seal or a ceramic seal can be used.

  In the present SOFC unit 2A, the unit cell 30 is placed and joined to the placement surface 22 of the fuel electrode side separator 20 via the internal sealing material 62 on the surface on the fuel electrode 33 side. The inner sealing material 62 is provided on the surface of the unit cell 30 on the fuel electrode 33 side, with the electrolyte layer 31 exposed to the outside in the surface direction of the fuel electrode 33 going around once. As a result, the fuel gas circulation portion F indicated by a thick line in FIG. 2 is surrounded by the surface on the fuel electrode 33 side of the fuel electrode side separator 20, the inner sealing material 62, and the unit cell 30, and is indicated by a thick line in FIG. 2. It is formed and is airtightly partitioned from the space on the air electrode 32 side. Then, by adjusting the height difference d1 between the frame surface 21 and the mounting surface 22 and the thickness of the internal sealing material 62, the surface on the air electrode 32 side of the electrolyte layer 31 of the single cell 30, that is, the electrolyte layer. The height of the interface between 31 and the air electrode 32 is substantially flush with the height of the frame surface 21. A fuel electrode side current collector 45 is disposed between the fuel electrode 33 of the single cell 30 and the first contact surface 23 of the fuel electrode side separator 20, and the fuel electrode side current collector 45 has a fuel electrode on each side. The surface 33 is in contact with the top surface of the first protrusion 23 a of the first contact surface 23.

  A fuel electrode side separator 20 is provided on the air electrode 32 side of the single cell 30 via an air electrode side current collector 40. The air electrode side current collector 40 is in contact with both the air electrode 32 and the top surface of the second protrusion 11a of the second contact surface 11 of the air electrode side separator 10 on both sides.

  Further, an area where the air electrode 32 and the air electrode side current collector 40 of the single cell 30 are provided between the frame surface 21 of the fuel electrode side separator 20 and the second contact surface 11 of the air electrode side separator 10 is an opening. An insulating frame 50 is disposed in the housing. An external sealing material 61 is disposed between the insulating frame 50 and the separators 10 and 20.

  Specifically, the external sealing material 61 (61a-61e) is provided in each area | region shown to Fig.3 (a), (b). That is, in the fuel electrode side separator 20, as shown in FIG. 3A, the external sealing material 61 a is arranged along two opposing sides of the frame surface 21 where the fuel supply holes 1 a are not provided. Furthermore, an outer seal material 61b is provided along the substantially U-shaped outer periphery of the fuel supply hole 1a on the frame surface 21. In addition, on the surface of the electrolyte layer 31 of the unit cell 30 having the same height as the frame surface 21, an external sealing material 61c is provided at a portion facing the fuel supply hole 1a. The external sealing material 61b on the frame surface 21 and the external sealing material 61c on the electrolyte layer 31 are continuously connected to each other so as to surround the outer periphery of the opening of the fuel supply hole 1a. On the other hand, in the air electrode side separator 10, as shown in FIG. 3B, the external sealing material 61 d is provided on the second contact surface 11 along the two opposing sides where the fuel supply holes 1 a are not provided. The outer seal material 61e is disposed around the outer periphery of the fuel supply hole 1a.

  As described above, each member is laminated and bonded, so that the mounting surface 22 and the first contact surface 23 of the fuel electrode side separator 20, the internal sealing material 62, and the fuel electrode of the single cell 30 as described above. As a space surrounded by the surface on the 33 side, a fuel gas circulation part F indicated by a bold line in FIG. 2 is formed. On the other hand, the air electrode side separator 10, the outer seal material 61, the insulating frame 50, the frame surface 21 and the mounting surface 22 of the fuel electrode side separator 20, the inner seal material 62, and the surface of the single cell 30 on the air electrode 32 side are surrounded. As a space, an air circulation part A is formed. The fuel gas circulation part F and the air circulation part A are airtightly isolated from each other by the internal sealing material 62, and mixing (internal leakage) of the fuel gas and air inside the SOFC unit 2A is suppressed. Further, the internal and external spaces of the SOFC unit 2A are hermetically partitioned by the external sealing material 61, and leakage of gas in the SOFC unit 2A to the outside (external leakage) is suppressed.

  By disposing the external sealing material 61 at each of the above positions, in the cell stack 3, a fuel supply path that supplies fuel gas to the fuel gas circulation part F of each unit cell 30 and air that supplies air to the air circulation part A The supply path can be separated from the other supply path and the outside and used for supplying each gas. That is, the fuel supply holes 1a provided in the separators 10 and 20 are linearly communicated with the fuel supply holes (not shown) provided in the insulating frame 50 to form an internal manifold type fuel supply passage. . The fuel supply path is separated from the outside and the air supply path by the external sealing materials 61b, 61c, 61e in a state where there is no gas mixing. On the other hand, in the cell stack 3, by providing an external manifold (not shown) for air supply outside the separators 10 and 20, along the side where the external sealing materials 61a and 61d of the separators 10 and 20 are not provided. Air can be circulated in the second flow path 11b through the gap. Thereby, air can be supplied by an external manifold system.

  As described above, the SOFC unit 2A and the cell stack 3 in which a plurality of the SOFC units 2A are stacked are assembled, and fuel gas is circulated through the internal manifold type fuel supply path constructed by the fuel supply holes 1a, and air is supplied from the external manifold. Thus, the fuel gas is supplied from the first flow path 23 b of the fuel electrode side separator 20 to the fuel gas circulation part F, and the air is supplied from the second flow path 11 b of the air electrode side separator 10 to the air circulation part A. Electric power can be generated in the single cell 30 by placing the SOFC unit 2A in this state at an operating temperature of 700 to 1000 ° C., for example.

  As a procedure for assembling the SOFC unit 2A having the above-described configuration, for example, in the first stage, the fuel electrode side current collector 45 is disposed between the first contact surface 23 and the mounting surface 22 of the fuel electrode side separator 20. It is placed on the first contact surface 23 so as to fit into the step. At this time, as the thickness of the fuel electrode side current collector 45, a thickness larger than the height difference d2 between the top surface of the first protrusion 23a of the first contact surface 23 and the mounting surface 22 is selected. It is preferable to keep it. And in the single cell 30, after applying the sealing material paste used as the internal sealing material 62 so that the outer periphery of the electrolyte layer 31 exposed to the surface at the side of the fuel electrode 33 may be made 1 round, Then, it is mounted on the mounting surface 22 with the surface on the fuel electrode 33 side facing down so as to fit into the step between the mounting surface 22 and the frame surface 21. Then, using the cushioning property of the fuel electrode side current collector 45, the height of the surface of the electrolyte layer 31 of the single cell 30 on the air electrode 32 side is aligned with the height of the frame surface 21 of the fuel electrode side separator 20. A load is applied from above the single cell 30 to crush the fuel electrode side current collector 45 and the sealing material. At this stage, the sealing material paste that becomes the layer of the internal sealing material 62 is cured as necessary. As will be described later, a power generation test may be performed at this stage to confirm the performance of the single cell 30 and the presence or absence of cracks.

  Next, in the second stage, an insulating frame 50 in which a sealing material paste to be the external sealing material 61 is applied to predetermined positions on both surfaces is placed on the placement surface 22 of the fuel electrode side separator 20. In the opening, the air electrode side current collector 40 is stacked on the air electrode 32 of the single cell 30. Further, the air electrode side separator 10 is disposed so as to cover the insulating frame 50 and the air electrode side current collector 40. The sealing material paste used as the external sealing material 61 may be applied to predetermined portions of the fuel electrode side separator 20 and the air electrode side separator 10 instead of the insulating frame 50. Then, a load is applied from above the air electrode side separator 10 while the sealant paste is crushed and brought into close contact with the members on both sides. In this state, the sealing material paste is cured.

  In the SOFC unit 2A according to the present embodiment, by having the above-described configuration, it is possible to easily obtain a high gas sealing performance as compared with the conventional general SOFC unit 100 as shown in FIG. it can. As described above, in the present SOFC unit 2A, the internal sealing material 62 suppresses internal leakage in which the fuel gas flowing through the fuel gas circulation portion F and the air flowing through the air circulation portion A are mixed, and the external sealing material. 61 prevents external leakage of these gases to the outside of the SOFC unit 2A. If internal leakage or external leakage occurs, the power generation efficiency in the SOFC unit is reduced.

  In the present SOFC unit 2A, the mounting surface 22 on which the single cell 30 is mounted is provided on the fuel electrode side separator 20, so that the single cell 30 is disposed in the in-plane direction with respect to the fuel electrode side separator 20. Positioning can be performed with high accuracy in the thickness direction. Since the internal sealing material 62 is disposed between the single cell 30 positioned in this way and the mounting surface 22 of the fuel electrode side separator 20, high positional accuracy can be obtained with respect to the formation of the internal sealing material 62. As a result, in the internal seal material 62, seal failure due to non-uniform thickness, in-plane positional deviation, and the like is unlikely to occur, and the occurrence of internal leakage can be suppressed to a high degree.

  In addition, since the insulating frame 50, the air electrode side current collector 40, and the air electrode side separator 10 are laminated on the upper layer in a state where the single cell 30 is fitted in the fuel electrode side separator 20, these members are spread over. In this arrangement, positioning becomes easy. Also in the formation of the external sealing material 61, it becomes easy to obtain a highly reliable sealing layer having a uniform thickness. In particular, as described above, in the first stage, the fuel electrode side current collector 45 and the single cell 30 in which the seal material is applied to a predetermined portion are fitted into the recesses of the fuel electrode side separator 20, and the seal material is temporarily used. If the SOFC unit 2A is assembled in two stages, after the curing and the formation of the internal sealant 62 is completed, the upper-layer members are arranged in the second stage and the external sealant 61 is formed. In addition, it is easy to achieve a highly reliable gas seal by reducing the influence of misalignment and the like in the internal seal material 62 and the external seal material 61. Further, as described above, if the height of the surface of the electrolyte layer 31 of the single cell 30 on the air electrode 32 side is aligned with the height of the frame surface 21 of the fuel electrode side separator 20, the respective members laminated on the upper layer are arranged. Positioning becomes easier. When the cell stack 3 is configured by stacking a large number of SOFC units 2A, the number of SOFC units 2A can be determined by repeating the positioning and seal formation according to the above procedure for each SOFC unit 2A. Even if there is an increase, the accuracy of positioning and gas sealing can be ensured in the SOFC unit 2A of each layer.

  The conventional general SOFC unit 100 shown in FIG. 7 has a structure in which both separators 110 and 120 are both plate-like members and can be positioned by fitting a single cell 130 or the like like the mounting surface 22. Not done. Therefore, in forming the internal sealing material 162 and the external sealing materials 161a and 161b, all the members are laminated after applying the sealing material paste at a predetermined location, and the positional deviation in the in-plane direction, the lifting in the thickness direction, etc. In order to prevent this from occurring, it is necessary to harden the sealing material in a state in which the respective members are constrained, to join the respective members, and to establish a gas seal by the internal sealing material 162 and the external sealing materials 161a and 161b. In this way, when forming the gas seal of each part at a time in a state where there is no structure capable of positioning, a place where the seal is incomplete occurs, and there is a high possibility of causing internal leakage or external leakage. . In particular, when a cell stack is configured by stacking a large number of SOFC units 100, it is necessary to simultaneously position and seal the constituent members of all SOFC units 100, thereby achieving highly accurate positioning and gas seal formation. It is very difficult to do. In the cell stack, if gas leaks due to seal failure even at one location, the power generation efficiency of the entire cell stack will be reduced.

  Further, when producing a cell stack using a sealing material such as a glass seal, the power generation performance cannot be confirmed until the sealing material is cured. In the case of a glass seal, it is necessary to cure at a high temperature. Further, when the sealing material is cured, the single cell may be broken by thermal stress. However, if a cell stack is configured using a sealing material, basically, the stack structure cannot be canceled and returned to the original state. When a cell stack is configured by using a conventional general SOFC unit 100, the power generation test of the cell stack cannot be performed unless all the SOFC units 100 are laminated together with the sealing materials 161 and 162 and cured. Further, even if it is discovered in the power generation test that some of the SOFC units 100 forming the stack structure are defective, it is not possible to replace only the SOFC unit 100. Therefore, it is necessary to satisfy the requirement that even a single unit cell 130 should not be mixed in the stack structure, and that even a single unit cell 130 should not crack when the sealing materials 161 and 162 are cured. In view of yield, very strict conditions are required in manufacturing the single cell 130, assembling it into a stack structure, and forming a seal.

  In contrast, when the cell stack 3 is manufactured using the SOFC unit 2A according to the above embodiment, the stacking of the single cell 30 and the separators 10 and 20 and the curing of the sealing materials 61 and 62 are performed using the SOFC unit 2A. Each layer can be completed, and a power generation performance test can be performed for each layer. In particular, in the first stage of the manufacturing method described above, the reference electrode is applied to the electrolyte layer 31 even when the single cell 30 is fitted into the fuel electrode side separator 20 via the internal seal material 62 and the internal seal material 62 is cured. If installed, a power generation test can be performed. Therefore, if there is a defect in the unit cell 30 itself or a crack in the unit cell 30 when the sealing material 62 is cured, it can be discovered and removed before the upper SOFC unit 2A is laminated. Therefore, even if the unit cell 30 itself or the yield of seal formation is not so high, the cell stack 3 having high power generation performance can be obtained.

  There is still another structural difference between the conventional general SOFC 100 and the SOFC unit 2A according to the present embodiment. That is, in the conventional general SOFC 100, the internal sealing material 162 is provided on the surface of the single cell 130 on the air electrode 132 side, and the fuel gas circulation portion F ′ occupies a wide area in the thickness direction of the SOFC unit 100. On the other hand, in the SOFC unit 2A according to the present embodiment, the internal sealing material 62 is provided on the surface of the single cell 30 on the fuel electrode 33 side, and the fuel gas circulation part F is in the thickness direction of the SOFC unit 2A. It is limited to a narrow area. In particular, the height of the surface of the electrolyte layer 31 on the air electrode 32 side is aligned with the height of the frame surface 21 of the fuel electrode side separator 20, and the entire fuel electrode 33 is positioned below the frame surface 21 of the fuel electrode side separator 20. As a result, the entire fuel gas circulation section F is formed inside the fuel electrode side separator 20, and the fuel gas leakage from the fuel gas circulation section F is ensured as long as the gas sealing performance by the internal sealing material 62 is ensured. Can be highly prevented. Also, due to the nature of the material, it is difficult to obtain high flatness with the insulating frame 50, and so on, at the joint between the insulating frame 50 and both separators 10 and 20 via the external seal material 61, Although there is a high possibility that gas leakage will occur compared to other locations, this junction is exposed in the fuel gas circulation portion F ′ in the conventional SOFC 100, and the possibility of fuel gas leakage cannot be excluded. On the other hand, in the SOFC unit 2A according to the present embodiment, the fuel gas is substantially leaked from the joint part because it is disposed in the air circulation part A, that is, outside the fuel gas circulation part F. It has been eliminated. In the unlikely event that an external leak occurs, the effect is greater in the case of fuel gas than in the case of air.

  As yet another difference from the conventional general SOFC 100, in the SOFC unit 2A according to the present embodiment, a thin film separator 112 as conventionally used is used both on the fuel electrode 33 side and on the air electrode 32 side. There are no points. The conventional general SOFC unit 100 absorbs the difference in thermal expansion between the separator 110 (or 120) made of a thick block-shaped metal material and the single cell 130 mainly made of solid oxide, and is due to the influence of thermal expansion. The thin film separator 112 is arranged as a kind of gasket for preventing the occurrence of seal failure. However, in the SOFC unit 2A according to the present embodiment, the unit cell 30 can be positioned with high accuracy with respect to the fuel electrode side separator 20 by the structure of the fuel electrode side separator 20 having the mounting surface 22. If the dimensions of each part of the fuel electrode side separator 20 are designed according to the single cell 30, the effect of thermal expansion is unlikely to lead to seal failure, so that it is not necessary to provide a thin film separator. Further, by disposing a fuel electrode side current collector 45 having cushioning properties between the single cell 30 and the first contact surface 23 of the fuel electrode side separator 20, dimensional errors and It is possible to effectively absorb the influence of the difference in thermal expansion. Thus, it is not necessary to use a thin film separator, so that it is possible to reduce the number of parts as compared with the prior art.

  As described above, in the SOFC unit 2A according to the present embodiment, by providing the fuel electrode side separator 20 with the step structure, the positioning accuracy between the single cell 30 and the fuel electrode side separator 20 and the gas sealing performance are improved. Although achieved, such a step structure also contributes to the selective supply of fuel gas to the fuel gas circulation part F. That is, the fuel supply hole 1a provided as a through hole in the frame surface 21 of the fuel electrode side separator 20 communicates with the first flow path 23b provided in the first contact surface 23 by the notch 1c. The fuel gas circulated through the hole 1a is supplied to the fuel gas circulator F through the notch 1c. On the other hand, since air is supplied from the external manifold through a gap formed between the adjacent fuel electrode side separator 20 and the air electrode side separator 10, the outer periphery of the opening of the fuel supply hole 1a is connected to the external sealing material 61b, The air supplied from the external manifold is prevented from entering the first flow path 23b by being surrounded and isolated by 61c and 61e. Thus, by using the step structure provided in the fuel electrode side separator 20 to position the single cell 30, a gas supply path for selectively supplying the fuel gas to the first flow path 23b can be constructed. it can. In general, when a parallel flow method in which the flow paths of fuel gas and air run in the same direction on the separator is used, there is a higher possibility of gas mixing compared to the cross flow method or the like, but the SOFC according to this embodiment In the unit 2A, the selective supply of the fuel gas to the first flow path 23b of the first contact surface 23 can be performed with high accuracy, so that even if the parallel flow method is adopted, gas mixing does not easily occur. ing. If the parallel flow method can be adopted, the degree of freedom is increased in the construction of piping in the cell stack 3.

  In addition, by using the step structure, as described above, an external manifold that uses an internal manifold system (closed system) to supply fuel gas and can simplify equipment than an internal manifold system to supply air A method (open flow method) can be used. It is also possible to supply air by an internal manifold system. In that case, a separate through-hole for supplying air is provided in the frame surface 21, and an appropriate sealing material is provided between the fuel supply passage 1a. What is necessary is just to arrange.

(2) Second Embodiment Next, the SOFC according to the second embodiment of the present invention will be described as a configuration in which the SOFC unit 2A according to the first embodiment is applied and the number of parts is further reduced. Here, only the configuration different from that of the SOFC unit 2A according to the first embodiment will be described, and unless otherwise specified, the configuration is the same as that of the SOFC unit according to the first embodiment.

  FIG. 5 shows an SOFC unit 2B constituting the SOFC according to the second embodiment. In the SOFC unit 2B according to the present embodiment, unlike the SOFC unit 2A according to the first embodiment, an insulating frame made of a rigid body is provided between the air electrode side separator 10 and the fuel electrode side separator 20. Absent. Instead, the air electrode side separator 10 is directly joined to the frame surface 21 of the fuel electrode side separator 20 only through the external seal material 61 formed by curing the seal material paste.

  The insulating frame 50 provided with a plurality of gas supply through holes such as those used in the SOFC unit 2A according to the first embodiment has been conventionally used in the SOFC, and the insulation and spacing between the separators. In addition to the above provisions, it has also played a role in separating the two gas supply paths. However, as described above, since the fuel gas supply path and the air supply path can be separated by using the step structure of the separator 1, an insulating frame is used like the SOFC unit 2B according to the present embodiment. Even if not, the separation can be achieved between the internal manifold type fuel gas supply path and the external manifold type air supply path by using only the sealing material applied in paste form. Further, when the air electrode side separator 10 and the fuel electrode side separator 20 are directly adjacent to each other via only the external seal material 61, an insulating frame is interposed therebetween as in the SOFC unit 2A according to the first embodiment. In comparison with this, the total area to which the sealing material paste to be the outer sealing material 61 is applied can be reduced.

  As described above, in the SOFC unit 2B according to the second embodiment, by removing the insulating frame, compared with the SOFC unit 2A according to the first embodiment, the number of members used and the application of the sealing material are reduced. It is possible to adopt the external manifold system while reducing the number of parts, and has the possibility of greatly simplifying the configuration of the SOFC cell stack.

(3) Third Embodiment Finally, the SOFC according to the third embodiment of the present invention will be described as a configuration in which the SOFC unit 2B according to the second embodiment is applied and the number of parts is further reduced. Here, only the configuration different from the SOFC units 2A and 2B according to the first and second embodiments will be described, and unless otherwise specified, the configurations are the same as those SOFC units 2A and 2B. .

  FIG. 6 shows an SOFC unit 2C constituting the SOFC according to the third embodiment. The SOFC unit 2C according to this embodiment is not provided with the fuel electrode side current collector 45 as used in the SOFC units 2A and 2B according to the first and second embodiments. Instead, the surface of the fuel electrode 33 of the single cell 30 is in direct contact with the top surface of the first ridge 23 a constituting the first contact surface 23 of the fuel electrode side separator 20.

  The fuel electrode side separator 20 used in the present SOFC unit 2C has a placement surface 22 on which the single cell 30 can be placed, and if the thickness of the internal sealing material 62 can be accurately controlled, the single cell 30 is provided. The positional relationship in the height direction between the fuel electrode side separator 20 and the fuel electrode side separator 20 is determined only by the height differences d1 and d2. Therefore, if the height difference d2 between the mounting surface 22 and the top surface of the first ridge 23a is made equal to the thickness of the fuel electrode 33, the fuel electrode side current collector having cushioning properties is interposed. Even if not, the surface of the fuel electrode 33 can be brought into close contact with the top surface of the first ridge 23a without being lifted. The inner sealing material 62 can be adjusted to some extent if a load is applied while it is in a paste state. After the single cell 30 is placed on the upper surface after the sealing material paste is applied thickly, If a load is applied from above, high adhesion can be obtained between the fuel electrode 33 and the first ridge 23a.

  Although the fuel electrode-side separator 20 has an appropriate design, even if the fuel electrode-side current collector is omitted, high adhesion can be obtained between the top of the first ridge 23a and the fuel electrode 33. Compared to the case where the pole-side current collector is used, there is a limit in improving the adhesion and preventing the deterioration of the adhesion due to thermal expansion. Therefore, as a material constituting the fuel electrode side separator 20, a material constituting the support of the single cell 30 as much as possible (for example, when the support is the electrolyte layer 31, zirconia or the like, when the support is the fuel electrode 33). It is preferable to use a material having a thermal expansion coefficient close to that of nickel or the like to improve adhesion and maintain adhesion during temperature rise. Preferably, the difference in thermal expansion coefficient between the support of the single cell 30 and the fuel electrode side separator 20 in the operating temperature range (room temperature to 1000 ° C.) of the SOFC unit 2C including the start / stop operation is less than 10 times (same order). It is good to be. Specific examples of the metal material constituting the fuel electrode side separator 20 include a chromium-based alloy whose composition is adjusted so as to have a thermal expansion coefficient close to that of zirconia. Further, the fuel electrode side current collector not only enhances the adhesion between the fuel electrode 33 and the first contact surface 23, but also causes pressure loss to the fuel gas flowing through the first flow path 23 b and is supplied to the fuel electrode 33. Although it also functions to increase the spatial uniformity of the fuel gas, in this embodiment, since this function of the fuel electrode side current collector cannot be used, the fuel gas supplied to the fuel electrode 33 From the viewpoint of improving the spatial uniformity of the first flow path 23b, it is desirable to narrow the width of the first flow path 23b and increase the density of the arrangement of the first flow paths 23b.

  In the SOFC unit 2C according to the third embodiment, compared with the SOFC unit according to the first embodiment shown in FIG. 2 and the like, the fuel electrode side current collector and the insulating frame are omitted. Yes. Furthermore, the air electrode side current collector 40 can also be omitted. In this case, the single separator 1 whose both surfaces function as the air electrode side separator 10 and the fuel electrode side separator 20, respectively, The SOFC unit can be formed with only three kinds of members, that is, the sealing materials 61 and 62. As described above, also in the SOFC unit 2A according to the first embodiment, it is possible to construct the cell stack 3 with a simpler configuration than the conventional general SOFC unit 100, because the external manifold method can be easily constructed. However, if the SOFC unit 2C according to the third embodiment is used, the configuration of the entire cell stack can be further greatly simplified.

  The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. In the above, the unit cell is placed on the surface on the fuel electrode side on the separator mounting surface, and the portion on the side where the first contact surface is provided is provided with the fuel electrode side separator and the second contact surface. However, the single cell is disposed on the mounting surface on the air electrode side surface, and the part on the side where the first contact surface is provided is used as the air electrode side separator. It is also conceivable to use the part on the side where the two contact surface is provided as the fuel electrode side separator. The second contact surface may not necessarily be provided, and may be used as only one of the fuel electrode side separator and the air electrode side separator.

DESCRIPTION OF SYMBOLS 1 Separator 1a Fuel supply hole 1c Notch 2A, 2B, 2C Solid oxide fuel cell (SOFC) unit 3 Cell stack 10 Air electrode side separator 11 Second contact surface 11a Second protrusion 11b Second flow path 20 Fuel electrode Side separator 21 Frame surface 22 Mounting surface 23 First contact surface 23a First protrusion 23b First flow path 30 (SOFC) single cell 31 Electrolyte layer 32 Air electrode 33 Fuel electrode 40 Air electrode side current collector 45 Fuel electrode side current collector 50 Insulating frame 61 (61a to 61e) External sealing material 62 Internal sealing material

Claims (14)

In the separator used by arranging on the fuel electrode side together with the solid oxide fuel cell single cell having the fuel electrode and the air electrode on both surfaces of the flat electrolyte layer,
A first contact surface on which a first flow path through which gas can flow is formed;
A frame-like mounting that is formed above the first contact surface and surrounds the outer periphery of the first contact surface, and on which the solid oxide fuel cell single cell can be mounted on the surface on the fuel electrode side Surface,
Above the placement surface, it possesses a frame-shaped frame surface formed to surround the outer periphery of the mounting surface, the integral,
The solid oxide fuel cell separator characterized in that a difference in height between the mounting surface and the frame surface is equal to or greater than a thickness of the fuel electrode of the solid oxide fuel cell single cell . The solid oxide fuel cell separator is:
A first contact surface, a mounting surface, a second contact surface provided on the back side of the frame surface, wherein a second flow path through which a gas can flow is formed;
The solid oxide fuel according to claim 1, further comprising a gas supply hole penetrating between the frame surface and the second contact surface and communicating with the first flow path. Battery separator.   3. The solid oxide fuel cell separator according to claim 2, wherein the first channel and the second channel run in the same direction. A solid oxide fuel cell single cell having a fuel electrode and an air electrode on both sides of a flat electrolyte layer;
A solid oxide fuel cell comprising the solid oxide fuel cell separator according to any one of claims 1 to 3 . A solid oxide fuel cell single cell having a fuel electrode and an air electrode on both sides of a flat electrolyte layer;
A fuel electrode side separator disposed outside the fuel electrode;
An air electrode side separator disposed outside the air electrode ,
The fuel electrode side separator is
A first contact surface on which a first flow path through which gas can flow is formed;
A frame-like mounting that is formed above the first contact surface and surrounds the outer periphery of the first contact surface, and on which the solid oxide fuel cell single cell can be mounted on the surface on the fuel electrode side Surface,
A frame-shaped frame surface formed so as to surround the outer periphery of the mounting surface above the mounting surface, and integrally,
The solid oxide fuel cell single cell is mounted on the surface on the fuel electrode side through an electrically insulating internal sealing material that blocks gas flow on the mounting surface of the fuel electrode side separator, A fuel gas circulation part through which fuel gas is circulated is formed as a space surrounded by the solid oxide fuel cell single cell, the fuel electrode side separator, and the inner seal material and partitioned from the outside. solid body oxide fuel cell you characterized. 6. The solid oxide according to claim 5, wherein a difference in height between the mounting surface and the frame surface is equal to or greater than a thickness of the fuel electrode of the solid oxide fuel cell single cell. Fuel cell. Between the fuel electrode and the first contact surface of the fuel electrode side separator, a current collector made of a conductive material that is more easily elastically deformed than the solid oxide fuel cell single cell and the fuel electrode side separator is disposed. 7. The solid oxide fuel cell according to claim 5 , wherein the solid oxide fuel cell is used. 7. The solid oxide fuel cell according to claim 5 , wherein the fuel electrode is in direct contact with the first contact surface of the fuel electrode side separator. The air electrode-side separator is joined to the frame surface of the fuel electrode-side separator through at least an electrically insulating external sealing material that is disposed outside the fuel gas circulation part and blocks gas flow. The solid oxide fuel cell according to claim 5 , wherein the solid oxide fuel cell is provided.   10. The solid oxide fuel cell according to claim 9, wherein the air electrode side separator is directly joined to the frame surface of the fuel electrode side separator via the external sealing material. The frame surface of the fuel electrode side separator of claim 5 to 10, characterized in that the electrolyte layer and the boundary surface and the height between the air electrode of the solid oxide fuel cell unit is aligned The solid oxide fuel cell according to any one of claims. The solid oxide fuel cell unit of the multiple is, are stacked via the solid body oxide fuel cell separator,
The solid oxide fuel cell separator integrally has the first contact surface, the mounting surface, and the frame surface on one surface,
A second contact surface provided on the back side of the one surface and formed with a second flow path through which a gas can flow;
A gas supply hole penetrating between the frame surface and the second contact surface and provided in communication with the first flow path;
The solid oxide fuel cell separator provided as the fuel electrode side separator of one solid oxide fuel cell single cell is a portion including the second contact surface, and the solid oxide fuel cell single cell The solid oxide fuel cell according to any one of claims 5 to 11, wherein the air electrode side separator of another solid oxide fuel cell single cell adjacent to the air cell is configured.   The solid oxide fuel cell according to claim 12, wherein the first flow path and the second flow path run in the same direction. The laminated structure of the solid oxide fuel cell single cell and the solid oxide fuel cell separator is provided with an external manifold for supplying air, and a gap between the adjacent solid oxide fuel cell separators. through the solid oxide fuel cell according to claim 12 or 13, characterized in that air is supplied to the second flow path from the external manifold.

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