JP2013004271A - Fuel cell, and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell which can retain satisfactory gas sealability of a gas sealing member contained in a frame body member laminated together with a cell body.SOLUTION: This fuel cell has a flat plate-like cell body 10 including an electrolyte layer 12 and electrode layers 11, 13 on both sides thereof, and a frame body member equipped with an opening part for exposing the electrode layer 13 of the cell body 10 in the thickness direction and laminated together with the cell body 10. The frame body member includes gas sealing members 26, 27 having multilayer structures formed by laminating multiple layers of a thin layer containing a ferro-silica mineral as a main component. A molten section formed by heating and melting the sectional part of the multilayer structure is formed on the inner peripheral end face forming the opening part of the frame body member in each of the gas sealing members 26, 27. Gas sealability against a gas supplied to the electrode layers 11, 13 can be improved by the molten section formed on the inner peripheral end face of each of the gas sealing members 26, 27.

Description

  The present invention relates to a fuel cell comprising a flat cell body and a frame-shaped frame member, and a fuel cell provided with a gas seal member for preventing gas leakage.

  Conventionally, a solid oxide fuel cell (SOFC) using a solid electrolyte (solid oxide) is known as a kind of fuel cell. For example, the SOFC is provided with a plate-like cell body in which a fuel electrode layer in contact with a fuel gas and an air electrode layer in contact with an oxidant gas (air) are arranged opposite to each other on both sides of a solid electrolyte, and a frame-like body around the cell body. It has a structure in which frame members are arranged. In the SOFC having such a structure, since it is necessary to isolate the fuel gas supplied to the fuel electrode layer and the oxidant gas supplied to the air electrode layer, for example, the cell body is integrally joined to the separator. This structure is adopted. The isolation separator is attached to a frame member including, for example, a metal frame surrounding the cell body. Since such a frame member has a structure in which a plurality of frame members are stacked, there is a risk that fuel gas or oxidant gas may leak from the gaps between the members. Therefore, it is desirable to employ a structure that prevents gas leaks by arranging gas leak members in close contact between the members of the frame member. For example, since mica sheets having various structures made of mica (a mica) which is a kind of ferrosilicate mineral are known (see, for example, Patent Documents 1 to 5), such mica sheets are used as gas seals for fuel cells. It can also be used as a member.

Japanese Patent Laid-Open No. 61-219493 Japanese Patent Laid-Open No. 2001-114312 JP 2003-246132 A JP 2009-276483 A Japanese Patent Application No. 2010-120839

  The mica sheet described above is, for example, a flat laminated sheet in which thin foil sheets made of mica crystals are laminated in multiple layers. With such a structure, a minute gap exists at the interface between the crystal layers of the mica sheet, which may act as a leak path for the fuel gas or the oxidant gas. In other words, a flat mica sheet maintains good sealing properties if only the front and back surfaces are exposed, but the end surface (side surface) where the multilayer structure exists is exposed in contact with gas. The sealability deteriorates. For this reason, the gas in the vicinity of the fuel gas flow path and the air flow path flows through the inner peripheral end face of the opening of the mica sheet, and the gas may leak to the outside via the leak path between the layers. There is a problem that the power generation efficiency of the fuel cell is reduced due to the occurrence of gas leak by such a mechanism. Further, there is a problem that the durability of the mica sheet deteriorates due to the frequent passage of gas through leak paths between layers of the mica sheet.

  The present invention has been made to solve these problems, and even when a gas seal member made of a ferrosilicate mineral such as mica is used, the gas seal property due to gas leak at the end face of the multilayer structure is used. An object of the present invention is to provide a fuel cell that can effectively prevent the deterioration of the gas sealing member and improve the durability of the gas seal member.

  In order to solve the above problems, a fuel cell according to the present invention includes a flat cell body including an electrolyte layer and electrode layers provided on both surfaces of the electrolyte layer, an opening in the thickness direction, A fuel cell having a frame-shaped frame member that is exposed from the opening and is laminated together with the cell body, wherein the frame member is composed mainly of a ferrosilicate mineral. A gas seal member having a multilayer structure formed by laminating thin layers is provided, and the gas seal member is formed by heating and melting a cross-sectional portion of the multilayer structure on an inner peripheral end surface forming the opening of the frame member. It is characterized in that a melted portion formed is formed.

  According to the fuel cell of the present invention, the gas seal member included in the frame member laminated integrally with the cell body of the fuel cell is formed by laminating thin layers mainly composed of ferrosilicate mineral. The melted portion is formed on the inner peripheral end face of the opening, and the cross-sectional portion of the multilayer structure is heated and melted. Normally, the gas seal member is in a state in which the multi-layer structure of each crystal layer is exposed on the side surface, but the multi-layer structure is directly formed by forming a heating and melting portion on the inner peripheral end face of the opening in the structure of the present invention. Is not exposed. Therefore, the gas seal member has a structure in which a leak path passing through the interface between the crystal layers is blocked at the inner peripheral end face, and thus it is possible to prevent the gas supplied from the gas flow path from escaping. Therefore, it is possible to improve the gas sealing property of the fuel cell and prevent the deterioration of the durability of the gas sealing member.

  As the gas seal member, for example, a mica sheet made of mica (mica) can be used. The mica sheet is a multi-layered sheet formed by bundling thin foil sheets made of mica crystals, and the cross-sectional structure of the multi-layered structure is exposed as a leak path on its side, so the leak path is blocked by forming a heating and melting part. can do. Mica is an insulating material having a sufficiently high resistance, and is suitable for a structure in which a mica sheet is disposed in contact with a metal frame or an interconnector.

  Laser processing can be employed as a heating means for forming the melting portion. That is, when the opening corresponding to the position of the cell main body is formed in the gas seal member, the inner peripheral end face may be heated simultaneously with the cutting process by irradiating the laser beam along the inner peripheral end face. . At this time, by appropriately adjusting the laser output and feed rate, the cross-sectional portion of the multilayer structure on the inner peripheral end face of the gas seal member can be sufficiently heated and melted, and the crystal structure can be altered to block the leak path. it can.

  The inner peripheral end surface that forms the melting portion in the gas seal member can be formed at various positions facing the gas flow path around the cell body. For example, in the case where the electrode layer is exposed from the opening in the thickness direction of the frame member, the electrode layer is preferably formed over the entire inner peripheral end surface facing the opening of the gas seal member. In this case, even if the melted part is not formed on the outer peripheral end face of the gas seal member, the gas does not flow as long as the melted part is formed on the entire inner peripheral end face. However, the present invention can be applied even if melted portions are formed on all end surfaces including the outer peripheral end surface of the gas seal member.

  The present invention can be applied to fuel cells having various structures. For example, a solid oxide fuel cell in which the electrolyte is made of a solid oxide and a fuel electrode layer and an air electrode layer are stacked as electrode layers on both sides can be mentioned. Further, the application target of the present invention includes a fuel cell stack in which a plurality of unit cells are stacked in addition to a fuel cell (unit cell) which is a basic structural unit of a fuel cell.

  Further, the method for producing a fuel cell of the present invention comprises a flat cell body comprising an electrolyte layer and electrode layers provided on both surfaces of the electrolyte layer, an opening in the thickness direction, In the method of manufacturing a fuel cell, the electrode layer is exposed from the opening, and the frame-shaped frame member is laminated together with the cell body. A thin layer mainly composed of a ferrosilicate mineral is multilayered. By preparing a gas seal member having a multilayer structure formed by stacking, the gas seal member is heated and melted along a planned cutting line so as to correspond to an inner peripheral end surface forming the opening of the frame member, The inner peripheral end face is cut and formed, a melted portion in which a cross-sectional portion of a multilayer structure is melted is formed on the inner peripheral end face, and the cell body and the frame member are stacked.

  In the fuel cell manufacturing method of the present invention, the melting portion can be formed by irradiating the inner peripheral end surface of the gas seal member with laser light from the thickness direction of the frame member. Moreover, a mica sheet can be used as the gas seal member. In this case, the melted portion can be formed by heating and melting the inner peripheral end face of the mica sheet by appropriately setting the output and feed speed of the laser beam.

  According to the present invention, in the fuel cell constituted by the cell body and the frame member, the gas seal member included in the frame member is formed by laminating thin layers mainly composed of ferrosilicate mineral, Since the cross-sectional portion of the multilayer structure on the inner peripheral end face of the opening is heated and melted, gas leakage via the crystal layer on the inner peripheral end face can be reliably prevented. Therefore, the gas seal property of the gas seal member can be improved, and the power generation efficiency of the fuel cell can be increased. In addition, the gas seal member can prevent an inflow of gas from the inner peripheral end face of the opening, so that an improvement in durability can be realized.

It is a side view of the solid oxide fuel cell of this embodiment. FIG. 2 is a top view of the solid oxide fuel cell of FIG. 1. It is a typical section structure figure of the state where each constituent element was disassembled about one unit cell. It is a top view of an interconnector in a unit cell. It is a plane structure figure of the metal frame in a unit cell. It is a top view of the isolation separator in a unit cell. It is a top view of a cell body in a unit cell. It is a top view of the gas seal member of the lower side in a unit cell. It is a top view of the upper gas seal member in the unit cell. It is a perspective view showing the structure of a gas seal member. It is a figure which shows the image example of the surface state of the inner peripheral end surface which has not taken a countermeasure in a gas seal member. It is a figure which shows the example of a surface state of the internal peripheral end surface which heat-processed in the gas seal member.

  Hereinafter, an embodiment of a solid oxide fuel cell to which the present invention is applied will be described in detail. FIG. 1 shows a side view of the solid oxide fuel cell 1 of the present embodiment, and FIG. 2 shows a top view of the solid oxide fuel cell 1 of FIG. 1 corresponds to a side view seen from the direction of arrow A in FIG.

  As shown in FIGS. 1 and 2, the solid oxide fuel cell 1 of the present embodiment is a fuel cell stack in which a plurality of fuel cell cells (hereinafter referred to as unit cells) 3, which are basic structural units, are stacked. 2 is provided. The fuel cell stack 2 is integrally fixed by a plurality of bolts B1 to B8 and a plurality of nuts N. Of the bolts B1 to B8, the four bolts B1, B3, B5, and B7 located at the four corners in the rectangular plane of FIG. 2 are used only as connecting members for fixing the fuel cell stack 2. On the other hand, among the bolts B1 to B8, the four bolts B2, B4, B6, and B8 positioned in the rectangular plane of FIG. 2 communicate with the through holes along the stacking direction in addition to the connecting members, respectively. It functions as a part of a fuel gas channel (fuel gas channel) or an oxidant gas channel (air channel). Specifically, the bolt B2 communicates with the fuel gas introduction pipe Fin on the inlet side of the fuel gas flow path, and the bolt B6 opposite to the bolt B2 communicates with the fuel gas discharge pipe Fout on the outlet side of the fuel gas flow path. . Further, the bolt B4 communicates with the air introduction pipe Ain on the inlet side of the air flow path, and the bolt B8 at a position opposite to the bolt B4 communicates with the air discharge pipe Aout on the outlet side of the air flow path.

  Next, the basic structure of the unit cell 3 included in the solid oxide fuel cell 1 of FIG. 1 will be described. FIG. 3 shows a schematic cross-sectional structure of each unit cell 3 in a state where each component is disassembled. The unit cell 3 shown in FIG. 3 includes a cell body 10 that performs a power generation function. The cell body 10 is formed by laminating a fuel electrode layer 11, a solid electrolyte layer 12, and an air electrode layer 13 in order from the lower layer side. The unit cell 3 includes a pair of upper and lower interconnectors 20, 21, a fuel electrode side current collector 22 disposed between the lower interconnector 20 and the fuel electrode layer 11, and an upper interconnector 21. The air electrode side current collector 23 disposed between the air electrode layer 13, the metal frame 24 surrounding the side surface of the fuel electrode layer 11, and the cell body 10 are integrally joined to the fuel electrode layer 11 side. An isolation separator 25 that separates the fuel gas flow path Fp from the air electrode layer 13 and a gas seal member 26 disposed between the metal frame 24 and the lower interconnector 20; And a gas seal member 27 disposed between the isolation separator 25 and the upper interconnector 21. Of the above, the metal frame 24, the separator 25, and the gas seal members 26 and 27 all have an opening having a shape described later at the center, and constitute a frame-like frame member in the unit cell 3. .

  The fuel electrode layer 11 is in contact with a fuel gas serving as a hydrogen source and functions as an anode of the unit cell 3. Since the fuel electrode layer 11 serves as a support base layer that supports the cell body 10, it is desirable to form the fuel electrode layer 11 with a sufficient thickness to ensure mechanical strength. For example, as the material of the fuel electrode layer 11, cermet made of metal particles such as Ni and ceramic particles can be used. The solid electrolyte layer 12 is made of various solid electrolytes having ionic conductivity. For example, as the material of the solid electrolyte layer 12, YSZ, ScSZ, SDC, GDC, perovskite oxide, or the like can be used. The air electrode layer 13 is in contact with air gas serving as an oxygen source and functions as a cathode of the unit cell 3. For example, as the material of the air electrode layer 13, perovskite oxides, various noble metals, and cermets of noble metals and ceramics can be used. The fuel electrode layer 11, the solid electrolyte layer 12, and the air electrode layer 13 all have a square (eg, square) planar shape.

  Hereinafter, the structure of the main components in the unit cell 3 will be described. In the following description, the planar structures of the members shown in FIGS. 4 to 9 are the same in FIG. First, the lower interconnector 20 is responsible for electrical connection with the unit cell 3 adjacent to the lower layer, and the upper interconnector 21 is responsible for electrical connection with the unit cell 3 adjacent to the upper layer. As shown in FIG. 4, the interconnectors 20 and 21 are thin metal plates made of, for example, ferritic stainless steel, and eight round holes through which the bolts B1 to B8 pass are formed in the outer edge portions. The fuel electrode side current collector 22 joined to the lower interconnector 20 is made of, for example, Ni felt having air permeability, and the air electrode side current collector 23 joined to the upper interconnector 21 is For example, it consists of a metal and a conductive ceramic.

  The metal frame 24 is made of a metal material such as ferritic stainless steel, for example, and has a role of fixing the cell body 10 and the separator 25 to the unit cell 3. As shown in FIG. 5, a square opening 30 is formed in the center of the metal frame 24. Further, four openings 31 are formed along the four sides of the metal frame 24, and four round holes corresponding to the bolts B1, B3, B5, and B7 are formed at the four corners. The four openings 31 are formed in a groove shape extending from the portion overlapping the round hole located at the center of each side of the interconnectors 20 and 21 to both sides in the side direction.

  The isolation separator 25 is formed in a frame-like thin plate having a thickness of about 0.02 to 0.3 mm using a metal material such as ferritic stainless steel as a flexible metal material. As shown in FIG. 6, a rectangular opening 32 is formed at the center of the separator 25, four openings 33 are formed along the four sides, and the bolts B1, B3, B5, B7 are formed at the four corners. Four corresponding round holes are formed. Among these, the four openings 33 and the four round holes are formed in the same position and the same shape as the metal frame 24. On the other hand, the central opening 32 is a square having a smaller size than the opening 30 of the metal frame 24 and is in a positional relationship facing the opening 30 of the metal frame 24 in the thickness direction.

  As shown in FIG. 7, the cell body 10 has a square outer peripheral shape. Since the cell body 10 is joined to the isolation separator 25, the cell body 10 has a rectangular outer peripheral shape that is smaller in size than the outer peripheral shape of the isolation separator 25 and larger in size than the opening 32 of the isolation separator 25. On the other hand, the outer peripheral shape of the upper air electrode layer 13 of the cell body 10 is smaller in size than the outer peripheral shape of the cell body 10, and is formed in a rectangular shape smaller in size than the opening 32 of the isolation separator 25. As a result, as shown in the cross-sectional structure of FIG. 3, the air electrode layer 13 can be exposed from the opening 32 in a state where the outer peripheral side of the cell body 10 is joined to the isolation separator 25.

  Next, the structure of the gas seal members 26 and 27 will be described as a characteristic structure of the unit cell 3 of the first embodiment. FIG. 8 shows a planar structure of the lower gas seal member 26, and FIG. 9 shows a planar structure of the upper gas seal member 27. The lower gas seal member 26 serves to gas seal the fuel gas supplied to the fuel electrode layer 11, and the upper gas seal member 27 gas seals the oxidant gas supplied to the air electrode layer 13. There is a role. In the present embodiment, as the gas seal members 26 and 27, mica sheets made of mica (mica) which is a kind of ferrosilicate mineral are used. Since mica has high insulating properties, the gas seal members 26 and 27 electrically insulate between the lower interconnector 20 and the metal frame 24 and between the upper interconnector 21 and the isolation separator 25. It is kept in the state.

  Since the lower and upper gas seal members 26 and 27 have the same basic structure and differ only in their arrangement, the structure of the lower gas seal member 26 will be described below as a representative. First, as shown in FIG. 8, an opening 34 is formed at the center of the gas seal member 26, and eight round holes through which the bolts B1 to B8 pass are formed at the outer edge. The central opening 34 is a square having a smaller size than the opening 30 of the metal frame 24, and has a positional relationship facing the opening 30 of the metal frame 24 and the opening 32 of the isolation separator 25 in the thickness direction. . The opening 34 is formed with four notches 34a each extending to the outer edge at two opposing sides of the square. These notches 34 a communicate with the two openings 31 on the two sides of the metal frame 24 and become a part of the fuel gas flow path Fp. Accordingly, the fuel gas taken in from the fuel gas introduction pipe Fin passes through the notch 34 a of the gas seal member 26, passes through the opening 34, and reaches the fuel electrode layer 11.

  Here, FIG. 10 is a perspective view showing the structure of the gas seal member 26 of FIG. FIG. 10 shows an inner peripheral end face IF including each square side surface portion of the central opening 34 of the gas seal member 26 and side surface portions constituting the eight notches 34a. . The fuel gas flowing through the fuel gas flow path Fp is in direct contact with the inner peripheral end surface IF. In FIG. 10, the fuel gas flowing through the fuel gas flow path Fp does not directly contact the outer peripheral end surface EF of the gas seal member 26. Since the gas seal member 26, which is a mica sheet, has a cross-sectional structure in which thin foil sheets made of mica crystals are laminated in multiple layers, for example, the inner peripheral end face IF when the opening 34 is formed by pressing or the like is a multilayer of crystal layers. The cross section of the structure is exposed. For this reason, when the gas seal member 26 is used in this state, a leak path is formed between the layers of the inner peripheral end face IF. In the present embodiment, as will be described in detail below, a countermeasure is taken against the formation of a leak path by performing a heat treatment on the inner peripheral end face IF to form a heat melting portion.

  Hereinafter, with reference to FIG.11 and FIG.12, the specific example of the countermeasure with respect to the leak path | pass with respect to the internal peripheral end surface IF of the opening part 34 is demonstrated regarding the gas seal member 26 of this embodiment. FIG. 11 shows an image example of the surface state of the inner peripheral end face IF that has not been countermeasured in the gas seal member 26 for comparison with the present embodiment. On the other hand, FIG. 12 shows an image example of the surface state of the inner peripheral end face IF subjected to the heat treatment in the gas seal member 26 of the present embodiment. On the unmeasured inner peripheral end face IF of FIG. 11, a multi-layer structure of multi-layer foil sheets of mica sheets is observed, and this acts as a striped leak path extending in the lateral direction. On the other hand, the inner peripheral end face IF after the countermeasure of FIG. 12 is obtained by heating and melting the inner peripheral end face IF with a laser from the state of FIG. 11, and the cross-sectional portion of the inner peripheral end face IF of FIG. Is in a modified state (crystal structure altered portion), and the leak path based on the multilayer structure in FIG. 11 disappears. In FIG. 12, a striped pattern in the vertical direction is formed on the inner peripheral end face IF. This is due to the laser light irradiated from the thickness direction. A specific heat treatment method for the inner peripheral end face IF by laser irradiation will be described later.

  As described above, when the fuel gas is supplied to the fuel electrode layer 11 by forming the melting portion based on the heat treatment shown in FIG. 12 over the entire inner peripheral end face IF of the opening 34 including the notch 34a. Even if the gas seal member 26 passes through the vicinity of the opening 34, the fuel gas can be blocked by the melting portion of the inner peripheral end face IF. Therefore, by applying the heat treatment of the present embodiment, the inner peripheral end face IF can be prevented from acting as a leak path, and the gas sealability of the gas seal member 26 can be improved. Thereby, the fall of the power generation efficiency of the unit cell 3 resulting from the gas leak of the gas seal member 26 can be prevented. Further, the fact that the fuel gas does not flow through the inner peripheral end face IF of the gas seal member 26 is effective in improving the durability of the gas seal member 26.

  On the other hand, the upper gas seal member 27 has the same basic structure as that of the lower gas seal member 26 as described above. However, as shown in FIG. 9, the planar structure of FIG. Has a planar structure. Therefore, an opening 35 is formed in the center of the gas seal member 27, and four cutouts 35a each extending to the outer edge are formed on two sides different from FIG. These notches 35a communicate with the two openings 31 on the two sides of the metal frame 24 and become a part of the air flow path Ap. Therefore, the oxidant gas taken in from the air introduction pipe Ain passes through the notch 35 a of the gas seal member 27, passes through the opening 35, and reaches the air electrode layer 13. In the present embodiment, it is assumed that the same heat treatment as in FIG. 12 is performed on the inner peripheral end face IF of the opening 35 of the gas seal member 27. Therefore, even when the oxidant gas is supplied to the air electrode layer 13, the inner peripheral end face IF is prevented from acting as a leak path, and the same effect as in the case of the gas seal member 26 described above can be obtained. .

  In the present embodiment, both the gas seal member 26 on the fuel electrode layer 11 side and the gas seal member 27 on the air electrode layer 13 side are subjected to a heat treatment on the inner peripheral end face IF to enhance gas sealability. However, the present invention is not limited to this, and only one of the gas seal members 26 and 27 may be subjected to heat treatment. For example, when the gas leak of the oxidant gas is sufficiently smaller than the gas leak of the fuel gas, the above heat treatment may be performed only on the gas seal member 26 on the fuel electrode layer 11 side.

  Next, with regard to the method for manufacturing the unit cell 3 of the present embodiment, processes mainly related to the characteristic structure of the present invention will be described. First, a laminated body including a fuel electrode green sheet and a solid electrolyte green sheet is formed by a well-known method, and a sintered body including the fuel electrode layer 11 and the solid electrolyte layer 12 is obtained by firing the laminate. Next, the air electrode layer 13 is formed on the upper layer of the sintered body to produce the cell body 10 having the planar structure of FIG. On the other hand, the separator 25 having the planar structure shown in FIG. 6 is manufactured by punching a metal plate, and as shown in FIG. 3, the outer peripheral side of the cell body 10 and the inner peripheral side of the separator 25 are, for example, a brazing material. Use to join them together.

  Moreover, the flat mica sheet used as the origin of the gas seal member 26 which has the characteristic structure of this invention is prepared. For example, a mica sheet made of soft mica is used as the gas seal member 26. And, by irradiating the surface of the mica sheet with a laser beam using, for example, a carbon dioxide laser, cutting is performed along the shape of the opening 34 in FIG. 8 and at the same time, the inner peripheral end face IF is heated and melted. Thus, the gas seal member 26 is produced. At this time, for example, the laser output is set to 110 W and the feed rate is set to 250 mm / min. In this case, the laser output is adjusted to a range in which the inner peripheral end face IF is heated to 1200 ° C. or more, which is the melting point of mica, and the inner peripheral end face IF is melted to form a melted portion made of a glass layer in the cross section. Is desirable. If the laser output is too large, many burrs are generated in the vicinity of the inner peripheral end face IF, which is not desirable. The laser type is not limited to a carbon dioxide laser, but the laser output and feed rate must be set appropriately according to the type of laser. Since the gas seal member 27 on the air electrode layer 13 side can also be manufactured in the same manner as the gas seal member 26 described above, the description thereof is omitted.

  On the other hand, the metal frame 24, the fuel electrode side current collector 22, the air electrode side current collector 23, and the interconnectors 20 and 21 are also manufactured by well-known methods, respectively, and then integrated with the cell body 10. The unit cell 3 can be obtained by integrating the separator 25 and the gas seal members 26 and 27 in the arrangement shown in FIG. Further, in a state where the unit cells 3 having such a structure are repeatedly arranged according to the number of stacked layers, the fuel having the structure of FIG. 1 is finally secured by integrally fixing with the plurality of bolts B1 to B8 and the plurality of nuts N. The battery stack 2 can be obtained.

  The present invention can be applied not only to the gas seal members 26 and 27 of the individual unit cells 3 constituting the fuel cell stack 2 but also to other members. For example, in the structure of FIG. 1, when an insulating member is inserted between the fuel cell stack 2 and each nut N, an insulating member made of a mica sheet may be used as with the gas seal members 26 and 27. In this case, the insulating member made of mica is provided with a circular opening for penetrating the bolts B1 to B8, and the inner peripheral end face of the opening is processed in the same manner as the inner peripheral end face IF of the gas seal members 26 and 27. Just give it. Thereby, it is possible to prevent the gas passing through the fuel gas passage and the air passage through which the bolts B1, B3, B5, and B7 communicate with each other from leaking from the opening of the insulating member.

  The contents of the present invention have been specifically described above based on the present embodiment, but the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. For example, the gas seal members 26 and 27 are not limited to mica sheets, and may be formed using other materials as long as they have a multilayer structure in which thin layers mainly composed of ferrosilicate mineral are laminated. can do. Further, the shape and dimensional conditions of the gas seal members 26 and 27 can be variously set within a range in which the object of the present invention can be achieved. Further, other members such as the metal frame 24 and the isolation separator 25 can be variously set without being restricted by the materials, shapes, dimensional conditions, and the like described in the above embodiment. Further, the processing method of the inner peripheral end face IF for forming the openings 34 and 35 with respect to the gas seal members 26 and 27 is not limited to laser irradiation as long as the object of the present invention can be achieved, and other means may be adopted. Regarding the other points, the contents of the present invention are not limited by the above embodiments, and can be appropriately changed as long as the effects of the present invention can be obtained.

DESCRIPTION OF SYMBOLS 1 ... Solid oxide fuel cell 2 ... Fuel cell stack 3 ... Unit cell (fuel cell)
DESCRIPTION OF SYMBOLS 10 ... Cell main body 11 ... Fuel electrode layer 12 ... Solid electrolyte layer 13 ... Air electrode layer 20, 21 ... Interconnector 22 ... Fuel electrode side collector 23 ... Air electrode side collector 24 ... Metal frame 25 ... Isolation separator 26 27 ... Gas seal members 34, 35 ... Gas seal opening B1-B8 ... Bolt N ... Nut Ain ... Air introduction pipe Aout ... Air discharge pipe Ap ... Air flow path Fin ... Fuel gas introduction pipe Fout ... Fuel gas discharge Pipe Fp ... Fuel gas flow path IF ... Inner peripheral end face of opening of gas seal part

Claims (9)

A flat cell body comprising an electrolyte layer and electrode layers provided on both sides of the electrolyte layer;
In a fuel cell comprising an opening in the thickness direction, exposing the electrode layer of the cell body from the opening, and having a frame-shaped frame member laminated together with the cell body,
The frame member includes a gas seal member having a multilayer structure formed by laminating thin layers mainly composed of ferrosilicate mineral,
The fuel cell according to claim 1, wherein the gas seal member has an inner peripheral end surface forming the opening of the frame member formed with a melted portion in which a cross-sectional portion of the multilayer structure is heated and melted. The melting portion of the gas seal member is
The fuel cell according to claim 1, further comprising a crystal structure altered portion whose crystal structure has been altered by heating. The melting portion of the gas seal member is
The fuel cell according to claim 1, wherein the inner peripheral end surface forming the opening is formed by laser irradiation.   The fuel cell according to any one of claims 1 to 3, wherein the melting portion is formed over the entire inner peripheral end surface.   The fuel cell according to any one of claims 1 to 4, wherein the gas seal member is a mica sheet.   The fuel cell according to any one of claims 1 to 5, wherein the electrolyte layer is made of a solid oxide. A flat cell body comprising an electrolyte layer and electrode layers provided on both sides of the electrolyte layer;
In a manufacturing method of a fuel cell, comprising a frame-shaped frame member that includes an opening in the thickness direction, exposes the electrode layer of the cell body from the opening, and is laminated together with the cell body.
Prepare a multi-layer gas seal member consisting of multiple layers of thin layers of ferrosilicate mineral as the main component,
The gas seal member is heated and melted along a planned cutting line so as to correspond to the inner peripheral end surface forming the opening of the frame member, so that the inner peripheral end surface is cut and formed. Forming a melted portion in which the cross-sectional portion of the multilayer structure is melted,
Laminating the cell body and the frame member;
A method for manufacturing a fuel cell.   The solid oxide fuel cell according to claim 7, wherein the melting portion is formed by irradiating the inner peripheral end surface of the gas seal member with a laser beam from a thickness direction of the frame member. Manufacturing method. The method of manufacturing a solid oxide fuel cell according to claim 7 or 8, wherein the gas seal member is a mica sheet.