JP2005339906A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell surely cutting off gas inside and outside a manifold and enhancing mass productivity. <P>SOLUTION: In the fuel cell in which each one end of a plurality of solid oxide fuel cells 62 is fixed to the manifold 58 and gas in the manifold 58 is passed through the fuel cells 62, the manifold 58 is equipped with a cell supporting plate 90a1 and a box-like manifold body 90b1 whose one side is opened, an inside circular step difference part 90b2 surrounding an opening part is formed in the inside part on the upper surface of a wall 90b1 forming the opening part of the manifold body 90b1, the outer circumferential part of the cell supporting plate 90a is engaged with the inside circular step difference part 90b2, and the opening part of the manifold body 90b1 is sealed with the cell supporting plate 90a1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel cell in which one end of a plurality of fuel cells is fixed to a manifold, and gas in the manifold passes through the fuel cells.

  In recent years, various types of fuel cells in which a plurality of solid oxide fuel cells are accommodated in a housing have been proposed as next-generation energy. A solid oxide fuel cell is configured, for example, by sequentially forming a solid electrolyte and a fuel side electrode on the surface of an oxygen side electrode. A fuel (hydrogen) is flowed to the fuel side electrode side, and air is supplied to the oxygen side electrode side. Electricity is generated at about 800 to 1000 ° C. by flowing (oxygen).

Conventionally, a fuel cell is known in which one end of a solid oxide fuel cell is housed in a cell-shaped housing recess formed on a top plate of a manifold and gas-sealed with a sealing material (see Patent Document 1). Also known is a fuel cell in which one end of a solid oxide fuel cell is housed in a cell-shaped housing recess formed on a support plate, and the support plate is fixed to a top plate of a manifold (Patent Document 2). reference).
JP 2003-282107 A JP 2003-282132 A

  From the viewpoint of mass productivity, the fuel cell manifold is preferably configured by joining a cell support plate constituting a top plate to a box-shaped manifold body whose upper surface is open. Therefore, the fuel cell manifold is required to have bonding reliability in order to reliably shut off the gas inside and outside the manifold.

  In addition, the fuel cell manifold is exposed to an oxidizing and reducing atmosphere in a high-temperature atmosphere and supports the fuel cell, so stress is generated at the joint between the manifold body and the cell support plate due to its weight and the like. Therefore, simply joining the cell support plate to the manifold body has low bonding reliability, and further bonding reliability has been required.

  An object of the present invention is to provide a fuel cell with high mass productivity that can reliably block gas inside and outside a manifold.

  The fuel cell of the present invention is a fuel cell in which one end portions of a plurality of solid oxide fuel cells are fixed to a manifold, and gas in the manifold passes through the fuel cells, and the manifold Comprises a cell support plate and a box-shaped manifold body having an opening on one side, and an inner annular stepped portion surrounding the opening is formed on an inner portion of the upper surface of the wall forming the opening of the manifold body. The inner annular stepped portion is engaged and joined with the outer peripheral portion of the cell support plate, and the opening of the manifold body is closed with the cell support plate.

  In such a fuel cell, since the outer peripheral portion of the cell support plate is engaged and joined to the inner annular step portion of the manifold body, the joint area is increased by the step portion, and the joint strength is improved. Since the path when gas leaks becomes long and resistance to gas leakage at the junction increases, gas leakage from the gas junction in the manifold can be prevented. In addition, since the cell support plate can be firmly joined to the manifold, even if the fuel cell placed upright on the cell support plate swings and stress is generated at the joint between the cell support plate and the manifold, the joining is released. This prevents gas leakage from the gas junction in the manifold.

  The fuel cell of the present invention is a fuel cell in which one end portions of a plurality of solid oxide fuel cells are fixed to a manifold, and gas in the manifold passes through the fuel cells, and the manifold Is provided with a cell support plate and a box-shaped manifold body having an opening on one side, and an outer annular stepped portion surrounding the opening is formed on an outer portion of the upper surface of the wall forming the opening of the manifold body. An annular protrusion formed on the outer peripheral portion of the cell support plate is engaged with and joined to the outer annular step portion, and the opening of the manifold body is closed with the cell support plate. .

  In such a fuel cell, since the annular convex portion formed on the outer peripheral portion of the cell support plate is engaged with and joined to the outer annular step portion of the manifold body, the joining area is increased by the step portion, and the joining strength is increased. In addition to the improvement, the path when the gas in the manifold leaks becomes longer, and the resistance to gas leakage at the junction increases, so that gas leakage from the gas junction in the manifold can be prevented. In addition, since the cell support plate can be firmly joined to the manifold, even if the fuel cell placed upright on the cell support plate swings and stress is generated at the joint between the cell support plate and the manifold, the joining is released. This prevents gas leakage from the gas junction in the manifold.

  The fuel cell of the present invention is a fuel cell in which one end portions of a plurality of solid oxide fuel cells are fixed to a manifold, and gas in the manifold passes through the fuel cells, and the manifold Comprises a cell support plate and a box-shaped manifold body having an opening on one side, and an engagement recess or an engagement protrusion on the outer surface of the cell support plate and the upper surface of the wall forming the opening of the manifold body. And the engagement concave portion or the engagement convex portion of the cell support plate is engaged with the engagement convex portion or the engagement concave portion of the manifold body, and the opening of the manifold main body is joined to the cell support. It is characterized by being closed with a plate.

  In such a fuel cell, since the engagement concave portion or the engagement convex portion of the cell support plate is engaged with the engagement convex portion or the engagement concave portion of the manifold body and joined, the joining area is increased and the joining strength is improved. At the same time, the path when the gas in the manifold leaks becomes long, and the resistance to gas leakage at the joint increases, so that gas leakage from the gas joint in the manifold can be prevented. In addition, since the cell support plate can be firmly joined to the manifold, even if the fuel cell placed upright on the cell support plate swings and stress is generated at the joint between the cell support plate and the manifold, the joining is released. This prevents gas leakage from the gas junction in the manifold.

  The fuel cell of the present invention is a fuel cell in which one end portions of a plurality of solid oxide fuel cells are fixed to a manifold, and gas in the manifold passes through the fuel cells, and the manifold Is provided with a cell support plate and a box-shaped manifold body having an opening on one side, and an engagement recess is formed on the outer surface of the cell support plate and the upper surface of the wall forming the opening of the manifold body, A sealing member that expands during operation of the fuel cell is accommodated in a space formed by both the cell support plate and the engagement recess of the manifold body, and the opening of the manifold body is closed by the cell support plate. It is characterized by becoming.

  In such a fuel cell, the temperature of the fuel cell becomes high during operation of the fuel cell, so that the sealing member expands and firmly engages both the cell support plate and the engagement recess of the manifold body, and the gas in the manifold Gas leakage from the joints can be prevented. In addition, since the cell support plate can be firmly joined to the manifold, even if the fuel cell placed upright on the cell support plate swings and stress is generated at the joint between the cell support plate and the manifold, the joining is released. This prevents gas leakage from the gas junction in the manifold. In this case, it is desirable to join using a sealing material.

  In any of the above cases, the sealing material used for joining is a dense sealing material in a solid state at the operating temperature of the fuel cell, and / or a coefficient of thermal expansion similar to that of the manifold body and the cell support plate. It is desirable to be a dense sealing material. In such a fuel cell, the cell support plate can be firmly joined to the manifold body by joining with a dense solid-phase sealant at the operating temperature of the fuel cell, and the inside of the manifold can be made airtight, During operation of the fuel cell, the cell support plate in which a plurality of fuel cells are erected can be firmly joined to the manifold.

  In addition, even when the temperature rises from room temperature to the operating temperature of the fuel cell by joining with a dense sealant similar in thermal expansion coefficient to the manifold body and cell support plate, the thermal expansion coefficient of the sealant Therefore, the cell support plate can be firmly joined to the manifold body, and the inside of the manifold can be made airtight. In particular, a dense sealing material that is in a solid state at the operating temperature of the fuel cell and has a thermal expansion coefficient similar to that of the manifold body and the cell support plate is desirable.

  Furthermore, the fuel cell of the present invention is characterized in that one end portion of the fuel cell is inserted and fixed in a plurality of cell fixing holes of the cell support plate. Further, in the fuel cell of the present invention, the concave portions corresponding to the cell shape for positioning and fixing the plurality of fuel cells at a predetermined interval are formed at predetermined intervals on the opposing inner wall surfaces of one cell fixing hole of the cell support plate. And one end of the fuel cell is accommodated and fixed between the opposing recesses.

  Furthermore, in the fuel cell of the present invention, the manifold includes a box-shaped cell support plate having an open bottom surface and a box-shaped manifold body having an open top surface, and a plurality of slits are formed in the cell support plate. In addition, the slit is gas-sealed with a sealing material in a state where one end portions of the plurality of fuel cells are respectively accommodated. In such a fuel cell, the plurality of slits formed on the top plate of the manifold can be formed by, for example, wire processing without using a device such as an NC lathe as in the prior art, and can be easily, inexpensively and quickly. A plurality of slits can be formed.

  In the fuel cell of the present invention, the manifold includes a cell support plate and a box-shaped manifold body having an upper surface opened, and a plurality of grooves are formed in the cell support plate. The gas from the manifold is gas-sealed by a sealing material in a state where one end of each of the plurality of fuel cells is accommodated, and the gas from the manifold is passed through a through hole formed in the concave groove of the cell support plate. It passes through the inside of the fuel cell. In such a fuel cell, for example, a groove can be formed on the cell support plate by wire processing, and a plurality of grooves can be easily formed at a low cost in a short time.

  Furthermore, the fuel cell of the present invention is characterized in that the fuel cell has a hollow plate shape.

  In the fuel cell of the present invention, the junction area is increased by the stepped portion and the like, the junction strength is improved, the path when the gas in the manifold leaks becomes long, and the resistance to gas leakage at the junction is increased. The gas leakage from the gas junction in the manifold can be prevented. In addition, since the cell support plate can be firmly joined to the manifold, even if the fuel cell placed upright on the cell support plate swings and stress is generated at the joint between the cell support plate and the manifold, the joining is released. This prevents gas leakage from the gas junction in the manifold.

  The fuel cell of the present invention will be described in further detail below with reference to the accompanying drawings.

  Referring to FIGS. 1 and 2, the illustrated fuel cell includes a substantially rectangular parallelepiped housing 2. The six wall surfaces of the housing 2 are heat insulating walls formed of an appropriate heat insulating material, that is, an upper heat insulating wall 4, a lower heat insulating wall 6, a right heat insulating wall 8, a left heat insulating wall 10, and a front heat insulating wall (not shown). ) And a rear heat insulating wall (not shown). A power generation / combustion chamber 12 is defined in the housing 2.

  The front heat insulation wall and / or the rear heat insulation wall are detachably or detachably mounted, and the power generation / combustion chamber 12 can be accessed by detaching or opening the front heat insulation wall and / or the rear heat insulation wall. If desired, an outer wall, which may be made of a metal plate, can be disposed on the outer surface of each heat insulating wall.

  A lower gas chamber 14 is disposed at the lower end in the housing 2, and an upper gas chamber 16 is disposed at the upper end. The lower gas chamber 14 is defined in a rectangular parallelepiped case 15 having a relatively small vertical dimension, and the upper gas chamber 16 is similarly defined in a rectangular parallelepiped case 17 having a relatively small vertical dimension. A communication gas chamber 18 extending in the vertical direction is disposed on both the left and right sides in the housing 2. The communication gas chamber 18 is defined in a rectangular parallelepiped case 19 having a relatively small size in the lateral direction (left-right direction in FIG. 1).

  Three communication cylinders 20 are attached to the upper surface of each communication gas chamber 18 at intervals in the front-rear direction, and each of the communication gas chambers 18 is provided on both sides of the lower surface of the upper gas chamber 16 via the communication cylinder 20. It communicates with the department. The inner sides of the lower ends of the communication gas chambers 18 are directly connected to both side surfaces of the lower gas chamber 14.

  Accordingly, both side portions of the upper gas chamber 16 are communicated with both side portions of the lower gas chamber 14 via the communication gas chamber 18. On the upper surface of the lower gas chamber 14, five hollow gas ejection plates 22 projecting upward at intervals in the lateral direction (left-right direction in FIG. 1) are arranged. The lower end of the gas ejection plate 22 communicates with the lower gas chamber 14, and a gas ejection hole (not shown) is formed in the upper part.

  A heat exchanger 24 having a flat plate shape as a whole is disposed on both sides of the housing 2, more specifically, inside the right heat insulating wall 8 and inside the left heat insulating wall 10. Each of the heat exchangers 24 is constituted by a case 26 having a hollow flat plate shape extending substantially vertically.

  A partition plate 28 located in the middle in the lateral direction is disposed in the case 26, and the inside of the case 26 is partitioned into a discharge path 30 positioned on the inner side and an inflow path 32 positioned on the outer side. Five partition walls 34 and 36 are arranged in the discharge path 30 at intervals in the vertical direction. More specifically, in the discharge passage 30, the front edge is located rearwardly away from the front wall (not shown) of the case 26, but the rear edge is the rear wall (not shown) of the case 26. And a partition wall 36 whose front edge is connected to the front wall of the case 26 but whose rear edge is spaced forward from the rear wall of the case 26. Are alternately arranged, and thus the combustion gas discharge passage 30 is zigzag-shaped. The combustion gas discharge passage 30 may have a form other than the zigzag flow passage if desired.

  Similarly, the five partition walls 38 and 40, that is, the front edges thereof are also spaced apart from the front wall (not shown) of the case 26 in the inflow path 32 with a space in the vertical direction. The rear wall is connected to the rear wall (not shown) of the case 26, and the front edge of the partition wall 38 is connected to the front wall of the case 26. The partition walls 40 spaced apart from the front are alternately arranged, and thus the inflow passage 32 is also zigzag-shaped. Note that the inflow channel 32 may have a form other than the zigzag type if desired.

  A discharge opening 42 is formed at the upper end of the inner wall of the case 26, and the discharge path 30 is communicated with the power generation / combustion chamber 12 through the discharge opening 42. In the illustrated embodiment, heat insulating members 44 and 46 are disposed between each of the heat exchangers 24 and the communication gas chamber 18 and on the inner surface of the communication gas chamber 18. The upper end of the exhaust gas is positioned substantially at the same level as or slightly below the lower edge of the discharge opening 42, and the discharge opening 42 is left above the heat insulating members 44 and 46 and the communication gas chamber 18. Is connected to the power generation / combustion chamber 12 through a space between the three communication cylinders 20 disposed at the upper end.

  An inflow opening 48 is formed on the outer side of the upper wall of the case 26, and the inflow path 32 is communicated with the upper gas chamber 16 through the inflow opening 48. A double cylinder 50 (only the upper end portion thereof is shown in FIG. 1) extending in the vertical direction is disposed behind each of the heat exchangers 24. The double cylinder 50 is an outer cylinder. The member 52 and the inner cylinder member 54 are configured. The lower end of the discharge path 30 is connected to the lower end of the discharge path defined between the outer cylinder member 52 and the inner cylinder member 54, and the lower end of the inflow path 32 is defined in the inner cylinder member 54. Connected to the inflow channel.

  Thus, the configuration of the fuel cell assembly shown in the drawing is substantially the same as the fuel cell assembly disclosed in the specification and drawings of Japanese Patent Application No. 2003-295790 filed by the present applicant. Therefore, the details of the configuration described above are left to the specification and drawings of Japanese Patent Application No. 2003-295790, and the description thereof is omitted in this specification.

  Four power generation units 56a, 56b, 56c and 56d are arranged on the upper surface of the lower gas chamber 14 described above. The power generation units 56a, 56b, 56c, and 56d are respectively positioned between the gas ejection plates 22 described above, arranged in parallel at a predetermined interval, and the fuel cell stack 57 is formed by the power generation units 56a, 56b, 56c, and 56d. Is configured. 5 together with FIGS. 1 and 2, the power generation unit 56a includes a rectangular parallelepiped fuel gas case 58a extending in the front-rear direction (a direction perpendicular to the paper surface in FIG. 1).

  A cell stack 60a is mounted on the upper surface of the fuel gas manifold 58a that defines the fuel gas chamber 59a. The cell stack 60a is formed by arranging a plurality of plate-like and column-like upright cells 62 extending vertically in the vertical direction in the longitudinal direction (that is, the front-rear direction) of the fuel gas manifold 58a. The arrangement direction of the fuel cells 62 and the arrangement direction of the power generation units 56 are orthogonal to each other. Each of the cells 62 includes an electrode support substrate 64, a fuel electrode layer 66 as an inner electrode layer, a solid electrolyte layer 68, an oxygen electrode layer 70 as an outer electrode layer, and an interconnector 72, as clearly shown in FIG. It is configured.

  The electrode support substrate 64 is a plate-like piece that is elongated in the vertical direction, and has both flat surfaces and both sides of a semicircular shape. The electrode support substrate 64 is formed with a plurality (six in the illustrated example) of fuel gas passages 74 penetrating the electrode support substrate 64 in the vertical direction. As will be described later, the lower end portion of the cell 62 is joined to the fuel manifold 58a by, for example, a sealing material having excellent heat resistance.

  On the upper wall of the fuel gas manifold 58a, a plurality of slits (not shown) extending in the left-right direction are formed at intervals in the direction perpendicular to the paper surface in FIG. A fuel gas passage 74 is connected to each of the slits, and thus to the fuel gas chamber 59a.

  The interconnector 72 is disposed on one surface of the electrode support substrate 64 (the upper surface in the cell stack 60a in FIG. 4). The fuel electrode layer 66 is disposed on the other surface (the lower surface in the cell stack 60a of FIG. 4) and both side surfaces of the electrode support substrate 64, and both ends thereof are joined to both ends of the interconnector 72. The solid electrolyte layer 68 is disposed so as to cover the entire fuel electrode layer 66, and both ends thereof are joined to both ends of the interconnector 72. The oxygen electrode layer 70 is disposed on the main part of the solid electrolyte layer 68, that is, on the portion covering the other surface of the electrode support substrate 64, and is positioned to face the interconnector 72 with the electrode support substrate plate 64 interposed therebetween. Yes.

  A current collecting member 76 is disposed between adjacent cells 62 in the cell stack 60a, and connects the interconnector 72 of one cell 62 and the oxygen electrode layer 70 of the other cell 62. Current collecting members 76 are disposed on both ends of the cell stack 60a, that is, on one side and the other side of the cell 62 positioned at the upper and lower ends in FIG. Electric power extraction means (not shown) is connected to the current collecting members 76 located at both ends of the cell stack 60a, and the electric power extraction means is the front wall (not shown) and / or the rear wall of the housing 2. It extends outside the housing 2 (not shown). If desired, the cell stacks 60a, 60b, 60c and 60d are connected in series with each other by appropriate connection means instead of disposing the power extraction means in each of the cell stacks 60a, 60b, 60c and 60d. Common power extraction means may be provided for the cell stacks 60a, 60b, 60c and 60d.

  More specifically about the cell 62, the electrode support substrate 64 is gas permeable to allow fuel gas to permeate to the anode layer 66, and is also conductive to collect current through the interconnector 72. Can be formed from a porous conductive ceramic (or cermet) that satisfies such requirements.

  In order to manufacture the electrode support substrate 64 by co-firing with the fuel electrode layer 66 and / or the solid electrolyte layer 68, it is preferable to form the electrode support substrate 64 from an iron group metal component and a specific rare earth oxide. In order to provide the required gas permeability, it is preferable that the open porosity is in the range of 30% or more, in particular 35 to 50%, and the conductivity is also 300 S / cm or more, in particular 440 C / cm or more. Is preferred.

The fuel electrode layer 66 can be formed of a porous conductive ceramic, for example, ZrO ₂ (referred to as stabilized zirconia) in which a rare earth element is dissolved and Ni and / or NiO.

The solid electrolyte layer 68 has a function as an electrolyte that bridges electrons between the electrodes, and at the same time has a gas barrier property to prevent leakage between the fuel gas and the oxygen-containing gas. It is necessary and is usually formed from ZrO ₂ in which ₃ to 15 mol% of a rare earth element is dissolved.

The oxygen electrode layer 70 can be formed of a conductive ceramic made of a so-called ABO ₃ type perovskite oxide. The oxygen electrode layer 70 is required to have gas permeability, and the open porosity is preferably 20% or more, particularly preferably in the range of 30 to 50%.

Although the interconnector 72 can be formed from a conductive ceramic, it needs to have reduction resistance and oxidation resistance because of contact with a fuel gas that may be hydrogen gas and an oxygen-containing gas that may be air. In addition, a lanthanum chromite perovskite oxide (LaCrO ₃ oxide) is preferably used. The interconnector 72 must be dense to prevent leakage of fuel gas passing through the fuel gas passage 74 formed in the electrode support substrate 64 and oxygen-containing gas flowing outside the electrode support substrate 64, and 93% As described above, it is particularly desirable to have a relative density of 95% or more.

  The current collecting member 76 can be composed of a member having an appropriate shape formed of a metal or alloy having elasticity, or a member obtained by adding a required surface treatment to a felt made of metal fiber or alloy fiber.

  Continuing the description with reference to FIGS. 1 to 3 and 5, the power generation unit 56 a has a rectangular shape (or cylindrical shape) that is elongated in the front-rear direction above the cell stack 60 a. A case 78a is also provided. One end, that is, the upper end of the fuel gas supply pipe 80a for the reformed fuel gas is connected to the side surface of the front end portion of the reforming case 78a.

  The fuel gas supply pipe 80a extends downward, then curves and extends rearward, and the other end of the fuel gas supply pipe 80a is connected to the front surface of the fuel gas manifold 58a. One end of a reformed gas supply pipe 82a to be reformed is connected to the rear surface of the reforming case 78a. The to-be-reformed gas supply pipe 82 a extends downward from the reforming case, and extends under the housing 2 and out of the housing 2. The insides of the fuel gas supply pipe 80a and the reformed gas supply pipe 82a are gas supply paths.

  The to-be-reformed gas supply pipe 82a is connected to a to-be-reformed gas supply source (not shown) which may be a hydrocarbon gas such as city gas, and is connected to the reforming case 78a through the to-be-reformed gas supply pipe 82a. A gas to be reformed is supplied. An appropriate reforming catalyst for reforming the fuel gas into a hydrogen-rich fuel gas is accommodated in the reforming case 78a.

  In the illustrated embodiment, the reforming case 78a is connected to the fuel gas manifold 58a via the fuel gas supply pipe 80a and is held in a required position by this, but if necessary, the two-dot chain line in FIG. For example, an appropriate support member 84a can be provided between the lower surface of the reformed gas supply pipe 82a and the upper surface or rear surface of the rear end portion of the fuel gas manifold 58a.

  Each of the power generation units 56a, 56b, 56c and 56d is on the upper surface of the case 15 which defines the lower gas chamber 14 between the gas injection plates 22, as will be clearly understood by referring to FIGS. It is placed and fixed in place by appropriate fixing means (not shown) such as a bolt.

  In the fuel cell assembly as described above, the gas to be reformed is supplied to the reforming cases 78a, 78b, 78c and 78d via the gas to be reformed supply pipes 82a, 82b, 82c and 82d, and the reforming case 78a. , 78b, 78c and 78d, the fuel defined in the fuel gas manifolds 58a, 58b, 58c and 58d through the fuel gas supply pipes 80a, 80b, 80c and 80d after being reformed into hydrogen-rich fuel gas. The gas chambers 59a, 59b, 59c and 59d are supplied to the cell stacks 60a, 60b, 60c and 60d.

  On the other hand, oxygen-containing gas, which may be air, is supplied to the inflow path 32 of the heat exchanger 24 through the inflow path defined in the inner cylinder member 54 of the double cylinder 50, and then the upper gas chamber 16 and the communication gas chamber 18. The gas is supplied to the lower gas chamber 14 through the gas injection plate 22 and is injected toward the cell stacks 60a, 60b, 60c and 60d from the injection holes of the gas injection plate 22.

In each of the cell stacks 60a, 60b, 60c and 60d, at the oxygen electrode,
1 / 2O ₂ + 2e ⁻ → O ²⁻ (solid electrolyte)
The electrode reaction of
O ²⁻ (solid electrolyte) + H ₂ → H ₂ O + 2e ⁻
The electrode reaction is generated and power is generated.

  The fuel gas and oxygen-containing gas that have flowed upward from the cell stacks 60a, 60b, 60c and 60d without being used for power generation are igniting means (not shown) disposed in the power generation / combustion chamber 12 at the time of startup. ) Is ignited and burned. As is well known, the temperature in the power generation / combustion chamber 12 becomes high, for example, about 1000 ° C. due to power generation in the cell stacks 60a, 60b, 60c and 60d, and also due to combustion of fuel gas and oxygen-containing gas. . The reforming cases 78a, 78b, 78c and 78d are disposed in the power generation / combustion chamber 12, and are positioned immediately above the cell stacks 60a, 60b, 60c and 60d, and are directly heated by the combustion flame. Thus, the high temperature generated in the power generation / combustion chamber 12 is effectively used for reforming the reformed gas.

  The combustion gas generated in the power generation / combustion chamber 12 flows into the discharge passage 30 from the discharge opening 42 formed in the heat exchanger 24, and flows through the discharge passage 30 extending in a zigzag shape. 50 is discharged through a discharge passage defined between the outer cylinder member 52 and the inner cylinder member 54. When the combustion gas flows through the discharge path in the double cylinder 50, the oxygen-containing gas flows through the inflow path in the double cylinder 50, and heat exchange is performed between the combustion gas and the oxygen-containing gas.

  In addition, when the combustion gas is caused to flow in the exhaust passage 30 of the heat exchanger 24 in a zigzag manner, the oxygen-containing gas is caused to flow in the inflow passage 32 of the heat exchanger 24 in a zigzag manner. Thus, heat is effectively exchanged between the combustion gas and the oxygen-containing gas, and the oxygen-containing gas is preheated. The oxygen-containing gas is heated by the high temperature in the power generation / combustion chamber 12 even when passing through the upper gas chamber 16, the communication gas chamber 18, and the lower gas chamber 14.

  When a part or all of the cell stacks 60a, 60b, 60c and 60d deteriorate due to power generation over a long period of time, the front wall (not shown) or the rear wall (not shown) of the housing 2 is shown. The power generation units 56 a, 56 b, 56 c and 56 d are partially or entirely removed from the housing 2.

  Then, replace some or all of the power generation units 56a, 56b, 56c and 56d with new ones, or only the cell stacks 60a, 60b, 60c and 60d in some or all of the power generation units 56a, 56b, 56c and 56d. May be replaced with a new one and mounted again at a required position in the housing 2. Even when it is necessary to replace the reforming catalyst accommodated in the reforming cases 78a, 78b, 78c and 78d in some or all of the power generation units 56a, 56b, 56c and 56d, the power generation units 56a, 56b , 56c and 56d are removed from the housing 2, and the reforming cases 78a, 78b, 78c and 78d themselves in the power generation units 56a, 56b, 56c and 56d are replaced with new ones or reforming cases. Only the reforming catalyst in 78a, 78b, 78c and 78d may be replaced with a new one.

  In order to be able to perform the replacement of the reforming catalyst in the reforming cases 78a, 78b, 78c and 78d sufficiently easily, a part of the reforming cases 78a, 78b, 78c and 78d can be opened and closed if desired. It can be put on the door.

  In the fuel cell of the present invention, for example, as shown in FIG. 6, the manifold 58 includes a cell support plate 90 a and a box-shaped manifold main body 90 b opened on one side, and an opening of the manifold main body 90 b is formed. An inner annular stepped portion 90b2 surrounding the opening is formed on the inner portion of the upper surface of the wall 90b1 to be formed, and the outer peripheral portion of the cell support plate 90a is engaged with and joined to the inner annular stepped portion 90b2, thereby opening the manifold main body 90b. Is closed by the cell support plate 90a. In other words, the cell support plate 90a is fitted inside the opened manifold main body 90b so as to cover it.

  The cell support plate 90a has a function of holding and fixing the lower end portion of the fuel cell 62. The cell support plate 90a is joined to the manifold body 90b, and the lower end portion of the fuel cell 62 is supported and fixed to the cell support plate 90a. Has been. The cell support plate 90a has a rectangular box shape with an open bottom surface, and a plurality of slits 90a1 are formed in parallel in the width direction at predetermined intervals. The lower end portions of the plurality of fuel cells 62 are formed in the slits 90a1. Are sealed with a sealing material in a state where each is accommodated.

As the gas seal material, a seal material that is dense in a solid phase at the operating temperature of the fuel cell and has a thermal expansion coefficient similar to that of the manifold body 90b and the cell support plate 90a is used. A crystalline glass composed of, for example, SiO ₂ , Al ₂ O ₃ , MgO, or ZnO, such as a crystalline material and / or a glass material containing crystalline material, and an inorganic cement, is used. In the fuel cell of the present invention, the operating temperature is about 750 ° C., but the crystalline glass has a softening temperature of about 790 ° C., and can maintain a solid state even at the operating temperature. The thermal expansion coefficient of the fuel cell used in the present invention is controlled by the electrode support substrate 64 having a large volume ratio, and is 11.5 × 10 ⁻⁶ / ° C. Further, the cell support 90a, the manifold The main body 90b is made of the same material, is 11.7 × 10 ⁻⁶ / ° C., the crystalline glass used as the sealing material is 11 × 10 ⁻⁶ / ° C., and the sealing material has a thermal expansion coefficient of the manifold main body 90b. And the cell support plate 90a. Such a gas seal material is filled in the interface of the portion where the cell support plate 90a contacts the manifold body 90b.

  As shown in FIG. 6A, the cell support plate 90a has dimensions such that the width direction end portion of the fuel cell 62 is placed on the width direction end portion (slit bottom surface 90a12) exposed from the slit 90a1. Then, as shown in FIG. 6B, the width direction end of the fuel cell 62 is configured not to protrude from the cell support plate 90a. Further, the flat side surface of the fuel cell 62 is separated from the side surface 90a11 of the slit 90a1 at a predetermined interval.

  In such a fuel cell, since the outer peripheral portion of the cell support plate 90a is engaged with and joined to the inner annular stepped portion 90b2 of the manifold body 90b, the joining area is increased, the joining strength is improved, and the inside of the manifold 58 is increased. Since the path when the gas leaks becomes long and the resistance against gas leakage at the joint portion increases, gas leakage from the gas joint portion in the manifold 58 can be prevented. Further, since the cell support plate 90a can be firmly joined to the manifold main body 90b, the fuel cell 62 standing on the cell support plate 90a swings, and stress is generated at the joint between the cell support plate 90a and the manifold main body 90b. However, the joining is not released, and the gas leakage from the joining portion of the gas in the manifold 58 can be prevented.

  In addition, when sealing the slit 90a1 of the cell support plate 90a and the fuel battery cell 62 with, for example, a paste-like sealing material flowing in, the gap between the fuel battery cell 62 and the slit 90a1, and the cell support plate 90a and the manifold The gap between the main bodies 90b can be gas-sealed at the same time.

  Further, as shown in FIG. 7, the manifold 58 includes a cell support plate 91a and a box-shaped manifold main body 91b having an opening on one surface, and is formed on the outer portion of the upper surface of the wall 91b1 forming the opening of the manifold main body 91b. The outer annular step portion 91b2 surrounding the opening is formed, and the annular protrusion 91a2 formed on the outer peripheral portion of the cell support plate 91a is engaged with and joined to the outer annular step portion 91b2. Is closed by a cell support plate 91a. In other words, the cell support plate 91a is fitted to the outside of the opened manifold main body 91b and covered. The cell support plate 91a has a function of holding and fixing the lower end portion of the fuel cell 62. The cell support plate 91a is joined to the manifold body 91b, and the lower end portion of the fuel cell 62 is supported and fixed to the cell support plate 91a. Has been. The cell support plate 91a has a rectangular box shape with an open bottom surface, and a plurality of slits 91a1 are formed in parallel in the width direction at predetermined intervals, and the lower end portions of the plurality of fuel cells 62 are disposed in the slits 91a1. Are sealed with a sealing material in a state where each is accommodated. The same gas sealing material as described above can be used. As shown in FIG. 7A, the cell support plate 91a has such a dimension that the end portion in the width direction of the fuel cell 62 is placed on the end portion in the width direction (slit bottom surface 91a12) exposed from the slit 91a1. Then, as shown in FIG. 7A, the width direction end of the fuel cell 62 is configured not to protrude from the cell support plate 91a. Further, the flat side surface of the fuel cell 62 is separated from the side surface 91a11 of the slit 91a1 at a predetermined interval.

  Even with such a fuel cell, the same effect as described above can be obtained, and the width of the cell support 91a1 can be made substantially the same as the width of the fuel cell 62, so that the inside of the manifold body as shown in FIG. The manifold can be made compact as compared with the case where the cell support plate is accommodated.

  As shown in FIG. 8, the cell support plate 92a may have a plate shape, and a plurality of cell insertion holes 92a1 having a shape similar to the cell in the width direction may be formed in parallel at a predetermined interval. These cell insertion holes 92a1 are gas-sealed with a sealing material in a state in which the lower ends of the plurality of fuel cells 60 are respectively accommodated. As shown in FIG. 8A, in the cell support plate 92a, the flat side surface of the fuel cell 62 is separated from the side surface 92a11 of the cell insertion hole 92a1 at a predetermined interval.

  As in the fuel cell shown in FIG. 6, such a fuel cell is formed with an inner annular step 92b2 surrounding the opening on the inner surface of the upper surface of the wall 92b1 that forms the opening of the manifold main body 92b. The outer periphery of the cell support plate 92a is engaged with the portion 92b2, joined with the sealing material, and the opening of the manifold main body 92b is closed with the cell support plate 92a.

  In such a fuel cell, substantially the same operation effect as the fuel cell shown in FIG. 6 can be obtained, but furthermore, by forming a plurality of cell insertion holes similar in shape to the cell, the fuel cell 62 and the cell The clearance between the insertion holes 92a1 is substantially equal, and the stress distribution caused by a slight difference in thermal expansion between the fuel cell, the cell support plate, and the seal material can be made uniform or reduced. In addition, cracks and cracks in the sealing material can be prevented.

  As shown in FIG. 9, the cell support plate 93a may have a rectangular box shape with an open bottom surface, and a plurality of cell insertion holes 93a1 may be formed in parallel in the width direction at a predetermined interval. These cell insertion holes 93a1 are gas-sealed with a sealing material in a state in which the lower ends of the plurality of fuel cells 62 are respectively accommodated. As shown in FIG. 9A, in the cell support plate 93a, the flat side surface of the fuel cell 62 is separated from the side surface 93a12 of the cell insertion hole 93a1 with a predetermined interval.

  An outer annular stepped portion 93b2 surrounding the opening is formed on the outer portion of the upper surface of the wall 93b1 forming the opening of the manifold main body 93b, and an annular protrusion formed on the outer peripheral portion of the cell support plate 93a is formed on the outer annular stepped portion 93b2. The part 93a2 is engaged and joined, and the opening of the manifold body 93b is closed by the cell support plate 93a. In such a fuel cell, substantially the same effect as that of the fuel cell shown in FIG. 7 can be obtained.

  As shown in FIG. 10, the manifold 58 includes a cell support plate 94a and a box-shaped manifold main body 94b having an opening on one side, and an annular engagement convex portion 94a2 is formed on the outer periphery of the cell support plate 94a. Then, an engagement recess 94b2 is formed on the upper surface of the wall 94b1 that forms the opening of the manifold body 94b, and the engagement protrusion 94a2 of the cell support plate 94a is engaged with the engagement recess 94b2 on the upper surface of the wall 94b1 of the manifold body 94b. They may be joined together.

  As shown in FIG. 11, the manifold 58 includes a cell support plate 95a and a box-shaped manifold main body 95b having one open surface. An annular engagement recess 95a2 is formed on the outer periphery of the cell support plate 95a. An engaging convex portion 95b2 is formed on the upper surface of the wall 95b1 forming the opening of the main body 95b, and the engaging concave portion 95a2 of the cell support plate 95a is engaged with the engaging convex portion 95b2 on the upper surface of the wall 95b1 of the manifold main body 95b. The above sealing material may be used for joining.

  10 and 11, the same effect as described above can be obtained.

  In addition, as shown in FIG. 12, the manifold 58 includes a cell support plate 96a and a box-shaped manifold main body 96b opened on one side, and an annular engagement recess 96a2 is formed on the outer periphery of the cell support plate 96a. An engagement recess 96b2 is formed on the upper surface of the wall 96b1 forming the opening of the manifold body 96b, and is formed by the engagement recess 96b2 on the upper surface of the wall 96b1 of the manifold body 96b and the engagement recess 96a2 of the cell support plate 96a. In the space, it expands when the fuel cell is operated, for example, a material larger than the thermal expansion of the manifold at the operating temperature of the fuel cell, and is heat-resistant ferritic stainless steel, aus and knight stainless steel, or high thermal expansion ceramics In the space formed by the recess 96a2 and the recess 96b2 A portion other than 7, the sealing material described above is filled. Even with such a fuel cell, the same effect as described above can be obtained.

  Further, as shown in FIG. 13, the manifold 58 is composed of a cell support plate 98a and a manifold body 98b, one cell fixing hole 98a1 is formed in the cell support plate 98a, and the inner wall surfaces of the cell fixing hole 98a1 facing each other. A recess 99 for positioning and fixing the fuel cell 62 at a predetermined interval is formed. The opposing recesses 99 have a shape corresponding to the cell shape so that both ends in the width direction of the fuel cells 62 are accommodated, and the fuel cell 62 is accommodated in the recesses 99 in a state in which the fuel cells 62 are accommodated. A sealing material is poured between the cells 62 and fixed. As described above, the cell support plate 98a is internally fitted or externally fitted to the manifold main body 98b.

  In such a fuel cell, since one cell fixing hole 98a1 is formed in the cell support plate 98a1, there is no partition between the holes for fixing the cell. Processing by a casting method (casting molding) becomes possible. In addition, since there is no partition between the holes for fixing the cells, even when the sealing material is filled between the cells, the inflow property of the sealing material is improved and the gas sealing property can be improved.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to such embodiments, and various modifications and corrections can be made without departing from the scope of the present invention. It goes without saying that this is possible.

  A plurality of concave grooves are formed in the cell support plate, and gas is sealed with a sealing material in a state where one end portions of the plurality of fuel cells are respectively accommodated in the concave grooves, and the concave grooves of the cell support plate are formed. Even if the gas from the manifold passes through the fuel cell through the through-hole formed in the above, the same effect as described above can be obtained. In this case, further, for example, a groove can be formed on the cell support plate by wire processing, and a plurality of grooves can be easily formed at a low cost in a short time.

1 is a cross-sectional view illustrating a preferred embodiment of a fuel cell configured according to the present invention. The perspective view which abbreviate | omits and shows the fuel cell of FIG. The perspective view which shows the fuel cell stack used for the fuel cell of FIG. Sectional drawing which shows the cell stack in the fuel cell stack of FIG. The perspective view which shows the electric power generation unit of FIG. The state which fits and joins the cell support plate which has a slit to a manifold main body is shown, (a) is a disassembled perspective view, (b) is a disassembled sectional view, (c) is a perspective view. The state which fits and joins the cell support plate which has a slit to a manifold main body is shown, (a) is a disassembled perspective view, (b) is a disassembled sectional view, (c) is a perspective view. The cell support plate which has a cell insertion hole is shown in the state which fits in a manifold main body, (a) is a disassembled perspective view, (b) is a disassembled sectional view, (c) is a perspective view. The state which externally fits and joins the cell support plate which has a cell insertion hole to a manifold main body is shown, (a) is a disassembled perspective view, (b) is a disassembled sectional view, (c) is a perspective view. The engagement convex part of a cell support plate is engaged with the engagement concave part of a manifold main body, and it shows the state joined, (a) is an exploded perspective view, (b) is an exploded sectional view, (c) is a perspective view. . The engagement concave part of a cell support plate is engaged with the engagement convex part of a manifold main body, and it shows the state joined, (a) is an exploded perspective view, (b) is an exploded sectional view, (c) is a perspective view. . Sectional drawing which shows the state which inserted the sealing member in the space formed by the engagement recessed part of a cell support plate, and the engagement recessed part of a manifold main body. The perspective view which shows the state which formed one cell solid hole in the cell support plate.

Explanation of symbols

2: Housing 58a, 58b, 58c and 58d: Fuel gas manifold 60a, 60b, 60c and 60d: Cell stack 62: Fuel cell 90a to 98a: Cell support plate 90b to 98b: Manifold body 90b2, 92b2: Inner annular stepped portion 91b2, 93b2: Inner annular stepped portions 94a2, 95b2: Engaging protrusions 94a1, 95b1: Engaging recesses 97: Sealing members 98a1: Cell fixing holes 99: Recesses

Claims (11)

A fuel cell in which one end of each of the plurality of solid oxide fuel cells is fixed to a manifold and gas in the manifold passes through the fuel cells, and the manifold includes a cell support plate, A box-shaped manifold body having an opening on one surface, and an inner annular stepped portion surrounding the opening is formed on an inner portion of the upper surface of the wall forming the opening of the manifold body, and the inner annular stepped portion is formed on the inner annular stepped portion. A fuel cell comprising: an outer periphery of a cell support plate engaged and joined; and the opening of the manifold body is closed with the cell support plate. A fuel cell in which one end of each of the plurality of solid oxide fuel cells is fixed to a manifold and gas in the manifold passes through the fuel cells, and the manifold includes a cell support plate, A box-shaped manifold body having an opening on one surface, and an outer annular stepped portion surrounding the opening is formed on an outer portion of the upper surface of the wall forming the opening of the manifold body. A fuel cell comprising: an annular convex portion formed on an outer peripheral portion of the cell support plate is engaged and joined, and an opening of the manifold body is closed with the cell support plate. A fuel cell in which one end of each of the plurality of solid oxide fuel cells is fixed to a manifold and gas in the manifold passes through the fuel cells, and the manifold includes a cell support plate, A box-shaped manifold body having an opening on one surface, and an engagement recess or an engagement protrusion is formed on an outer peripheral portion of the cell support plate and an upper surface of the wall forming the opening of the manifold body, and the cell The engagement concave portion or the engagement convex portion of the support plate is engaged with and engaged with the engagement convex portion or the engagement concave portion of the manifold body, and the opening of the manifold body is closed with the cell support plate. A fuel cell. A fuel cell in which one end of each of the plurality of solid oxide fuel cells is fixed to a manifold and gas in the manifold passes through the fuel cells, and the manifold includes a cell support plate, A box-shaped manifold body having an opening on one side, and an engagement recess is formed on an outer peripheral portion of the cell support plate and an upper surface of the wall forming the opening of the manifold body, and the cell support plate and the manifold body A sealing member that expands during operation of the fuel cell is accommodated in a space formed by both of the engaging recesses of the fuel cell, and the opening of the manifold body is closed with the cell support plate. battery. The cell support plate is joined to the opening of the manifold body by a dense seal material in a solid phase at the operating temperature of the fuel cell and / or a dense seal material having a thermal expansion coefficient similar to that of the manifold body and the cell support plate. The fuel cell according to any one of claims 1 to 4, wherein the fuel cell is formed. The fuel cell according to any one of claims 1 to 5, wherein the cell support plate has a plate shape or a box shape with one side opened. The fuel cell according to any one of claims 1 to 6, wherein one end of the fuel cell is inserted and fixed in a plurality of cell fixing holes of the cell support plate. Concave portions corresponding to cell shapes for positioning and fixing a plurality of fuel cells at a predetermined interval are formed at predetermined intervals on the opposing inner wall surfaces of one cell fixing hole of the cell support plate. 7. The fuel cell according to claim 1, wherein one end of the fuel cell is accommodated and fixed between the recesses. The manifold includes a box-shaped cell support plate having an open bottom surface and a box-shaped manifold body having an open top surface, and a plurality of slits are formed in the cell support plate, and a plurality of fuels are formed in the slit. The fuel cell according to any one of claims 1 to 6, wherein the battery cell is gas-sealed by a sealing material in a state in which one end portion of the battery cell is accommodated. The manifold includes a cell support plate and a box-shaped manifold body having an open top surface, and a plurality of grooves are formed in the cell support plate, and one end of a plurality of fuel cell units is formed in the recess. Gas is sealed with a sealing material in a state in which each is contained, and gas from the manifold passes through the fuel cell through a through-hole formed in the concave groove of the cell support plate. The fuel cell according to any one of claims 1 to 6, wherein The fuel cell according to any one of claims 1 to 10, wherein the fuel cell has a hollow plate shape.

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