JP2005129314A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell capable of preventing breakage of a fuel battery cell and opening of a cell stack. <P>SOLUTION: This fuel cell is provided with the cell stack 60 wherein a plurality of fuel battery cells 62 are fixed to a manifold 58 with a prescribed gap in an erected condition and a current collecting member 76 is interposed between the adjacent fuel battery cells 62. A frame body 92 is provided at a distal end of the cell stack 60 to surround the distal end. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel cell.

  In recent years, various fuel cells in which a plurality of fuel battery cells are stored in a storage container have been proposed as next-generation energy.

  A conventional solid oxide fuel cell is configured by storing a plurality of fuel cells in a storage container and electrically connecting the fuel cells to each other in series or in parallel by a current collecting member. It was performed at a high temperature of about 600 to 1000 ° C. by supplying an oxygen-containing gas and a fuel gas to the cell.

Conventionally, a metal felt-like member in which fibrous metals are gathered has been used as a current collecting member for electrical connection between fuel cells. In such a metal felt, the applicant has filed an application using a plate-like metal as a current collecting member because the connection between cells deteriorates with time (see, for example, Patent Document 1). This Patent Document 1 describes a fuel cell in which a plurality of fuel cells are provided upright in a fuel gas tank and a plate-like current collecting member is interposed between these fuel cells.
JP 2003-282101 A

  However, in the fuel cell described above, a current collecting member is interposed between adjacent fuel cells, and the side surface of the adjacent fuel cell is widened by the elastic force of the current collecting member. Since the electrical connection was ensured in this way, a force that spreads the fuel cell acts, the force acts on the fixed part of the fuel cell, breaks, and the cell stack opens. There was a problem to do. In particular, when the elastic force of the current collecting member is increased in order to ensure electrical connection between the fuel cells, the tendency is strong.

  An object of the present invention is to provide a fuel cell capable of preventing breakage of a fuel cell and preventing opening of a cell stack.

  A fuel cell according to the present invention includes a cell stack in which a plurality of fuel cells are fixed to a manifold in a state of being erected at a predetermined interval, and a current collecting member is interposed between the adjacent fuel cells. In addition, a frame body surrounding the tip is provided at the tip of the cell stack.

  In the fuel cell of the present invention, the fuel cells are electrically connected so as to expand the side surfaces of the adjacent fuel cells by the elastic force of the current collecting member. Since the frame that surrounds the tip of the cell stack is provided at the tip of the cell stack as well as securing the connection, even if the side surface of the fuel cell is pushed and widened by the elastic force of the current collecting member, Opening of the stack is prevented, deformation of the fuel cell is suppressed, and breakage at the fixed portion of the fuel cell can be reliably prevented.

  Moreover, the fuel cell of the present invention is characterized in that the fuel cell has an inactive portion that does not contribute to power generation at the tip, and a frame surrounds the inactive portion. In such a fuel cell, the power generation performance is not affected because the frame body is not in contact with the power generation portion of the fuel cell.

  Furthermore, the fuel cell according to the present invention is characterized in that the frame body includes a frame portion that surrounds the periphery of the cell stack and an abutting portion that abuts on the front end surface of the fuel cell. In such a fuel cell, since the frame body has a contact portion that contacts the front end surface of the fuel cell, the frame body can be reliably positioned at the front end portion of the cell stack.

  The fuel cell of the present invention is characterized in that one end of the fuel cell is inserted and fixed in a cell insertion hole provided in the cell support plate. In addition, one end of the fuel cell is integrally joined and fixed in an arrayed state, and is erected on the cell support plate. Further, the cell support plate constitutes a part of the manifold.

In such a fuel cell, for example, one end portion of the fuel cell is inserted and fixed in the insertion hole of the cell support plate, or one end portion of the plurality of fuel cells is solidified by filling with a bonding agent. By fixing, the cell stack can be easily formed. By using the cell support plate of such a cell stack as the top plate of the manifold, the fuel cell can be easily erected on the manifold.

The fuel cell of the present invention is characterized in that the current collecting member is plate-shaped. In such a fuel cell, since a plate-shaped current collecting member is used, the force to push and spread the fuel cell is large, and thus the present invention can be suitably used.

  In addition, by using a plate-shaped current collecting member, it comes into surface contact with the side surface of the fuel cell, and the area contacting the fuel cell is larger than that of the conventional felt-shaped current collecting member. Can be improved. Further, since the current collecting member is plate-shaped, the elastic force is large, and even if vibration or the like occurs, sufficient contact with the fuel cell can be ensured for a long time.

  Furthermore, since the current collecting member is plate-shaped, even when the temperature is high, it is harder to sinter than the conventional felt-shaped current collecting member, and sufficient contact with the fuel cell can be ensured for a long time.

  Since the fuel cell of the present invention electrically connects the fuel cells by pushing the side surfaces of the adjacent fuel cells by the elastic force of the current collecting member and electrically connecting the fuel cells, Connection can be secured and the frame is fitted to the tip of the cell stack, so even if the side surface of the fuel cell is pushed and expanded by the elastic force of the current collector, the frame opens the cell stack. Can be prevented and the breakage of the fuel cell can be surely prevented. Furthermore, since the opening of the cell stack is suppressed by the frame, the current collecting member between the fuel cells strongly contacts the fuel cells, and the electrical connection can be maintained for a long time.

  Hereinafter, a fuel cell of the present invention will be described in detail with reference to the 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.

  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.

  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 as described above in the illustrated fuel cell 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. The details of the configuration described above will be referred to the specification and drawings of the above Japanese Patent Application No. 2003-295790, and description thereof will be 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. 3 together with FIGS. 1 and 2, the power generation unit 56a includes a rectangular parallelepiped fuel gas manifold 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 configured by arranging a plurality of upright cells 62 extending in the vertical direction in the longitudinal direction (that is, the front-rear direction) of the fuel gas manifold 58a. As clearly shown in FIG. 4, each cell 62 includes an electrode support substrate 64, a fuel electrode layer 66 that is an inner electrode layer, a solid electrolyte layer 68, an oxygen electrode layer 70 that is an outer electrode layer, and an interconnector 72. Has been.

  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. A plurality (four in the illustrated example) of fuel gas passages 74 penetrating through the electrode support substrate 64 in the vertical direction are formed. As will be described later, each of the cells 62 is joined to the upper wall (top plate) of the fuel gas manifold 58a by, for example, glass having excellent heat resistance, and the fuel gas passage 74 of the cell 62 communicates with the fuel gas chamber 59a. I'm damned.

  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. End side current collecting members 109 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 end and the lower end in FIG.

  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 simultaneous firing with the fuel electrode layer 66 and / or the solid electrolyte layer 70, 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, and particularly preferably within 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 interconnect 72 must be dense in order to prevent leakage of the fuel gas passing through the fuel gas passage 74 formed in the electrode support substrate 64 and the oxygen-containing gas flowing outside the electrode support substrate 64, and more than 93% In particular, it is desirable to have a relative density of 95% or more.

  The current collecting member 76 can be composed of a plate formed from a metal or alloy having elasticity or a member obtained by subjecting a felt made of metal fiber or alloy fiber to a required surface treatment. .

  Continuing the description with reference to FIGS. 1 to 3, the power generation unit 56a is advantageously a rectangular shape (or a cylindrical shape) that is elongated in the front-rear direction above the cell stack 60a. It also has. One end, that is, the upper end of the fuel gas supply pipe 80a is connected to the lower 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 is connected to the rear surface of the reforming case 78a. The reformed gas supply pipe 82a extends substantially horizontally and extends out of the housing 2 through the rear wall (not shown) of the housing 2.

  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 thereby held in a required position. 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.

  The power generation unit 56c is substantially the same as the power generation unit 56a described above. The power generation units 56b and 56d are disposed opposite to the power generation units 56a and 56c in the front-rear direction, and accordingly, the fuel gas supply pipe (which connects the reforming cases 78b and 78d and the fuel gas manifolds 58b and 58d) (Not shown) is arranged on the rear side, and the reformed gas supply pipes 82b and 82d are extended from the front surfaces of the reforming cases 78b and 78d through the front wall (not shown) of the housing 2. The power generation units 56a and 56c are the same except that

  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.

  Further, in the fuel cell of the present invention, as described above and as shown in FIG. 5, the lower end portion of the fuel cell 62 is provided in the fuel gas manifold 58 in a state where the plurality of fuel cells 62 are erected at a predetermined interval. A cell stack 60 is provided between the adjacent fuel battery cells 62, and a current collecting member 76 is interposed therebetween.

A frame 92 made of a ceramic insulator surrounding the tip is provided at the tip of the cell stack 60.

  The frame body 92 includes a frame portion 92 a that surrounds the cell stack 60 and a contact portion 92 b that contacts the front end surface of the fuel cell 62. The contact portion 92 b is in contact with both end portions in the width direction on the front end surface of the fuel cell 62. Thereby, the frame body 92 can be reliably positioned at the tip of the cell stack 60. Further, the oxygen-containing gas ejected from the hollow gas ejection plate 22 between the fuel cells 62 passes through between the fuel cells 62 because the current collecting member 76 is interposed between the fuel cells 62. The oxygen-containing gas easily passes between the cell stacks 60, and therefore, the oxygen-containing gas easily passes through both end portions in the width direction of the fuel battery cell 62, and the oxygen-containing gas wraps around the front end surface of the fuel battery cell 62. There is a risk that the electrode support substrate 64 is oxidized and expanded to cause cracks and the like in the width direction end portion, but the contact portion of the frame 92 is in contact with the width direction end portion of the fuel cell 62. Therefore, the end of the fuel cell 62 in the width direction can be protected, oxidation can be prevented, and the occurrence of cracks in the cell 62 can be suppressed.

  Further, the fuel cell 62 has an inactive portion 62a that does not contribute to power generation at the tip, and the frame 92 abuts or surrounds the inactive portion 62a. That is, the fuel cell 62 includes a power generation unit 62b that sandwiches the solid electrolyte 68 between the pair of electrodes 66 and 70, and an inactive unit 62a that is not sandwiched. The power generation unit 62b includes the fuel cell 62. The tip portion of the burning fuel cell 62 is formed at the center in the length direction of the fuel cell 62 and is an inactive portion 62a. Since the frame 92 is located in the inactive part 62a, it does not affect the power generation performance.

1-3, the description of the frame 92 is omitted, and the current collecting member is omitted in FIGS. 5 (a) and 5 (b). Further, since the fuel cell passage hole is present in the front end surface of the fuel cell 62, the frame 92 on the cell arrangement direction side preferably has no contact portion 92b so as not to disturb the flow of the fuel gas. . Even if it is formed, it is necessary to have a width that does not hinder the passage of the fuel gas through the fuel gas passage hole.

The lower end portion of the cell 62 is inserted and fixed in a cell insertion hole 99 provided in the cell support plate 97, and this cell support plate 97 constitutes the top plate of the fuel gas manifold 58. In this case, the structure can be simplified and the manufacture becomes easy. A cell support plate may be fixed to the upper surface of the fuel gas manifold. In this case, gas tightness in the fuel gas manifold can be improved. In this case, a through hole is formed in the top plate of the fuel gas manifold, and the through hole and the fuel gas passage 74 of the cell communicate with each other.

  A plurality of fuel cells may be arranged in a line, and the lower ends may be integrally bonded and fixed in this state, and the cells may be erected on the cell support plate. In this case, for example, the lower end portions of a plurality of aligned fuel cells can be accommodated in a mold, and a glass pace can be poured into the mold, heated and cured, and the mold can be removed. The cell stack can be easily formed.

The fuel cell 62 is bonded and fixed in the cell insertion hole 99 of the fuel gas manifold 58 with an insulating material such as glass or ceramic. Joining can be made by filling the gap with glass paste or the like and heating the fuel cell 62 inserted into the cell insertion hole 99.

In the fuel cell configured as described above, the gas to be reformed is a gas to be reformed supply pipe (FIG. 2 shows two gas feed pipes 82b and 82d to be reformed, and FIG. The reformed gas is supplied to the reforming cases 78a, 78b, 78c and 78d via the reformed gas supply pipe 82a), and is reformed into hydrogen-rich fuel gas in the reforming cases 78a, 78b, 78c and 78d. After that, the fuel gas chamber 59a defined in the fuel gas manifolds 58a, 58b, 58c and 58d through the fuel gas supply pipe (two fuel gas supply pipes 80a and 80c are shown in FIG. 2). , 59b, 59c and 59d, and then 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, the plate-like current collecting member 76 having a spring property mechanically connects the flat side surfaces of the opposed fuel cells 62 so as to push the spaces between the fuel cells 62. The fuel cell 62 is in surface contact, and the area in contact with the fuel cell 62 is larger than that of a conventional felt-shaped current collecting member, so that the current collecting characteristics can be improved. Further, since the current collecting member 76 is plate-shaped, the elastic force is large, and even if vibration or the like occurs, sufficient contact with the fuel cell 62 can be ensured for a long time.

  Further, since the current collecting member 76 is plate-shaped, even when the inside of the housing 2 becomes high temperature, it is harder to sinter than the conventional felt-shaped current collecting member, and sufficient contact with the fuel cell 62 is achieved. Can be secured for a long time. Further, since the current collecting member 76 is plate-shaped, the plate-shaped current collecting member 76 is easily and reliably disposed between the interconnector 72 of one fuel cell 62 and the oxygen side electrode 70 of the other fuel cell 62. Can intervene.

  Further, since the fuel cell 62 is electrically connected by pushing the side surface of the adjacent fuel cell 62 with the elastic force of the current collecting member 76 so that the fuel cell 62 is electrically connected, Since the frame body 92 is fitted to the tip of the cell stack 60, the frame body 92 allows the cell body 62 to be expanded even if the side surface of the fuel cell 62 is pushed out by the elastic force of the current collecting member 76. Opening of the stack 60 can be prevented, and breakage at the fixed portion of the fuel cell 62 can be reliably prevented. Further, since the opening of the cell stack 60 is suppressed by the frame 92, the current collecting member 76 between the fuel cells 62 strongly contacts the fuel cells 62, and the electrical connection can be maintained for a long period.

  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. For example, the present invention has been described in relation to a fuel cell having a substantially rectangular parallelepiped housing with a specific heat exchanger. The present invention can also be applied to a fuel cell provided with another appropriate form of housing such as a housing formed of multiple cylindrical bodies.

  In the above embodiment, the fuel cell 62 has a flat shape as shown in FIG. 4 and has a plurality of fuel gas passage holes 74. However, the fuel cell has one fuel gas passage. The shape of the fuel cell is not particularly limited, such as a cylinder.

  Furthermore, in the above example, the example in which the fuel cells 62 are connected in series has been described, but it is needless to say that they may be connected in parallel. Further, although the fuel side electrode 66 is an inner electrode, the oxygen side electrode 68 may be an inner electrode.

  In the present invention, as shown in FIG. 6, cell stack holding members 121 are provided at both ends of the cell stack in the arrangement direction, and the lower ends of the cell stack holding members 121 are screwed to the side surfaces of the fuel gas manifold with screws or the like. However, the cell stack holding member 121 may be surrounded by the frame 92. In this case, an end side current collecting member 109 is interposed between the cell stack holding member 121 and the outermost fuel cell 62, and current is externally passed through the end side current collecting member 109. It can be pulled out. In addition, when the cell stack holding member 121 is made of a conductive material, current can be drawn through the cell stack holding member 121. Furthermore, in this case, the cell stack 60 can be reliably held by the cell stack holding member 121.

Further, as shown in FIG. 7, the lower end portion of the cell stack holding member 131 may be inserted and fixed in the insertion hole of the manifold 58. In this case, the fixing of the cell stack holding member can be strengthened more than in FIG.

Further, as shown in FIG. 8, the lower end portion of the cell stack holding member 141 may be merely brought into contact with the side surface of the outermost fuel cell 62 without being fixed to the gas manifold 58.

6 to 8, the plate-shaped cell stack holding members 121, 131, and 141 are used, but a through hole is formed in the cell stack holding member from the viewpoint of sufficiently supplying gas to the fuel cell 62. However, gas may be supplied to the electrode through the through hole.

Sectional drawing which shows suitable embodiment of the fuel cell of this invention. FIG. 2 is a perspective view showing the fuel cell of FIG. 1 with a part thereof omitted. The slope view which shows the electric power generation unit currently used for the fuel cell of FIG. Sectional drawing which shows the cell stack in the electric power generation unit of FIG. The state which provided the frame at the front-end | tip part of a cell stack is shown, (a) is a perspective view, (b) is an enlarged view of a part of (a), (c) is an enlarged part of (a). FIG. The perspective view which screwed the cell stack holding member on the side of the fuel gas manifold. The perspective view which inserted and fixed the lower end part of the cell stack holding member in the insertion hole of the fuel gas manifold. The perspective view which has arrange | positioned the cell stack holding member on the side surface of the cell stack.

Explanation of symbols

58 (58a, 68b, 58c and 58d): Fuel gas manifold 60 (60a, 60b, 60c and 60d): Cell stack 62: Fuel cell 76: Current collecting member 92: Frame body 92a: Frame portion 92b: Contact portion 97: Cell support plate 99: Cell insertion hole

Claims (7)

A plurality of fuel cells are fixed to a manifold in a state where they are erected at a predetermined interval, and a cell stack having a current collecting member interposed between the adjacent fuel cells is provided. A fuel cell, characterized in that a frame surrounding the tip is provided at the tip. The fuel cell according to claim 1, wherein the fuel cell has an inactive portion that does not contribute to power generation at the tip, and a frame surrounds the inactive portion. 3. The fuel cell according to claim 1, wherein the frame includes a frame that surrounds the periphery of the cell stack, and a contact portion that contacts the front end surface of the fuel cell. 4. The fuel cell according to claim 1, wherein one end of the fuel cell is inserted and fixed in a cell insertion hole provided in the cell support plate. 5. 4. The fuel cell according to claim 1, wherein one end portion of the fuel cell is integrally joined and fixed in an arrayed state and is erected on the cell support plate. 5. 6. The fuel cell according to claim 4, wherein the cell support plate constitutes a part of the manifold. The fuel cell according to claim 1, wherein the current collecting member has a plate shape.

Images