JP2006331881A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell with good power generating property and durability with a reduced number of pipes in a power generation/combustion chamber, easily retaining power generating temperature, with a simple structure and which can be made compact. <P>SOLUTION: The fuel cell is provided with a cell stack group in which a plurality of cell stacks with a plurality of solid electrolyte fuel cells arranged in one column, one fuel gas manifold supplying fuel gas to each fuel cell and a reforming machine provided above the cell stack group. The reforming machine is an approximate U shape provided with an outward path case, a connecting case and a return path case containing reforming catalyst in one part and the gas to be reformed is supplied to the outward path case and the fuel gas is fed out from the return path case. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell, and in particular, a fuel having a fuel gas manifold in which a plurality of solid oxide fuel cells are mounted in a power generation / combustion chamber, and a reformer for reforming a reformed gas into a fuel gas. It relates to batteries.

  In recent years, various fuel cells in which a plurality of solid electrolyte fuel cells are accommodated in a housing have been proposed as next-generation energy. A solid electrolyte 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, and fuel (hydrogen) is flowed to the fuel side electrode side, and air is supplied to the oxygen side electrode side. Electricity is generated by flowing (oxygen).

  Conventionally, one end of a solid oxide fuel cell is erected on a top plate of a fuel gas manifold, and a single cell stack composed of a plurality of fuel cells is provided on the fuel gas manifold, and reforming is performed above the cell stack. A fuel cell provided with a vessel is known (see Patent Document 1). Furthermore, the applicant has filed an application for a fuel cell in which a plurality of cell stacks are erected on a fuel gas manifold and a reformer is provided above the plurality of cell stacks (see Patent Document 2).

For example, FIG. 9 shows the main part of the fuel cell described in Patent Document 2. One cell stack is formed by arranging a plurality of fuel cells in a row. In the power generation / combustion chamber, a plurality of cell stacks 141, 142, 143, 144 are erected on the plurality of fuel gas manifolds 161, 162, 163, 164, respectively. In addition, a plurality of reformers 131, 132, 133, and 134 are disposed above the plurality of cell stacks, respectively. Reformed gas is supplied to each reformer, and the reformed fuel gas is transferred from each reformer to each fuel gas manifold. In such a fuel cell, to-be-reformed gas is supplied to each of a plurality of reformers through a plurality of to-be-reformed gas supply pipes 111, 112, 113, and 114, and fuel from the plurality of reformers is supplied. The gas is supplied to a plurality of fuel gas manifolds through a plurality of reformed gas supply pipes 122, 123, 124, and the like. Fuel gas is supplied from each fuel gas manifold to each cell stack.
JP 2004-319420 A Japanese Patent Laying-Open No. 2005-93081

  In the conventional fuel cell, the reformed gas supply pipe, the reformer, and the fuel gas supply pipe are provided for each cell stack. Therefore, the number of pipes is large, miniaturization cannot be achieved, and the structure is complicated. was there. Furthermore, there is a possibility that the amount of gas supplied from each reformed gas supply pipe to each reformer and the amount of gas supplied from each reformer to each fuel gas manifold may be uneven. In particular, the amount of fuel gas supplied to each cell stack may be non-uniform. As a result, the performance and durability of the fuel cell may be adversely affected.

  In addition, since the fuel gas manifold is provided for each cell stack, the fuel gas manifold is in the way, the distance between the cell stacks cannot be reduced, the distance between the cells is widened, and heat is easily dissipated. There was a problem that it was difficult to maintain the temperature. There is also a problem that miniaturization cannot be achieved. Further, the piping to each fuel gas manifold is complicated, and the amount of gas supplied to the fuel gas manifold becomes non-uniform, which may adversely affect the performance and durability of the fuel cell.

  An object of the present invention is to provide a fuel cell that reduces the number of pipes in a power generation / combustion chamber, makes it possible to easily maintain a power generation temperature, and achieves downsizing with a simple structure and good durability. There is to do.

In order to achieve the above object, the present invention provides the following configurations.
(1) In the fuel cell according to claim 1, a plurality of cell stacks in which a plurality of solid electrolyte fuel cells are arranged in a line in the front-rear direction are arranged in the left-right direction in a power generation / combustion chamber provided in the housing. A cell stack assembly, a fuel gas manifold mounted with each fuel cell to supply fuel gas to each fuel cell of the cell stack assembly, and a modification provided above the cell stack assembly. A reformer, and the reformer comprises an outward case and a return case arranged in parallel to each other in a horizontal plane, and a connection case for connecting ends of the forward case and the return case. It is U-shaped and contains a reforming catalyst in a part thereof, to-be-reformed gas is supplied to the forward case, and fuel gas is sent from the return case.

(2) The fuel cell according to claim 2 is the fuel cell according to claim 1, wherein the cell stack assembly is composed of a left cell stack group and a right cell stack group each including the same number of the cell stacks. The forward case extends in the front-rear direction above the stack group, and the return case extends in the front-rear direction above the other cell stack group.

(3) The fuel cell according to claim 3 is characterized in that, in claim 2, the number of cell stacks included in the cell stack assembly is two or four.

(4) The fuel cell according to claim 4 is the fuel cell according to any one of claims 1 to 3, wherein the oxygen-containing gas chamber disposed above the power generation / combustion chamber includes a plurality of oxygens depending on the power generation / combustion chamber. A gas introduction pipe is provided, and a part of the plurality of oxygen-containing gas introduction pipes is inserted and disposed between the cell stacks through the forward case and the return case.

(5) The fuel cell according to claim 5 is the fuel cell according to claim 4, wherein another part of the plurality of oxygen-containing gas introduction pipes is inserted and arranged on each of the left and right outer sides of the cell stack assembly. Features.

(6) The fuel cell according to claim 6 is characterized in that, in claim 4 or 5, a heat insulating material is arranged between the cell stacks in which the oxygen-containing gas introduction pipe is not inserted.

(7) The fuel cell according to claim 7 is characterized in that in any one of claims 1 to 6, a vaporizer is provided in a part of the reformer.

(8) The fuel cell according to claim 8 is the fuel gas introduction case according to any one of claims 1 to 7, wherein the fuel gas introduction case is erected in communication with the fuel gas manifold at a front-rear direction end of the cell stack assembly. And a fuel gas transfer pipe connecting the return case of the reformer and the upper part of the fuel gas introduction case.

In the fuel cell according to claim 1, the reformer provided above the cell stack assembly arranged in a plurality of rows in the left-right direction in the power generation / combustion chamber has an outward case in which a substantially U-shape is formed, A reforming catalyst is accommodated in a part of the case and the return case, the reformed gas is supplied to the forward case, and the reformed fuel gas is sent out from the return case. In other words, in the process in which the gas to be reformed flows from the forward case to the connection case and then to the return case, it is reformed by the reforming catalyst and delivered as fuel gas. Therefore, the gas path for the process of reforming the reformed gas into the fuel gas is integrated into one substantially U-shaped reformer. Thereby, the nonuniformity of the supply amount when the reformed gas is distributed and supplied through a plurality of pipes as in the prior art can be eliminated. As a result, there is no problem caused by uneven gas distribution. In addition, the cost can be reduced by simplifying a plurality of complicated pipes.

  In addition, since the reformer has a substantially U shape, a space for passing the oxygen-containing gas introduction pipe can be secured between the forward case and the backward case arranged in parallel to each other. This is useful when oxygen-containing gas is introduced into the power generation / combustion chamber from the oxygen-containing gas chamber provided above the power generation / combustion chamber.

  Furthermore, by making the reformer substantially U-shaped, the forward path case and the backward path case are arranged in parallel, that is, adjacent to each other. For example, if a vaporization unit that supplies water to a part of the forward case to generate water vapor is provided, the temperature of the cell stack group located below it is likely to decrease, but the return case adjacent to the forward case is kept at a high temperature. Therefore, it has an effect of compensating for and mitigating the temperature decrease due to the vaporization part.

  Further, in the power generation / combustion chamber, the fuel gas and oxygen-containing gas that have not been used for power generation are combusted to generate combustion gas, which is discharged from the power generation / combustion chamber, but the reformer has a substantially U shape. Thus, it is possible to discharge not only from the front, rear, left and right of the cell stack assembly but also from the central space of the substantially U-shaped reformer, which is efficient.

  In addition, by attaching the cell stack assembly to one fuel gas manifold, the distance between the cell stacks can be reduced, the density of the fuel cells can be increased, the power generation temperature can be easily maintained, and the size can be reduced. it can. Further, the fuel gas reformed by the reformer can be collectively supplied to the fuel gas manifold and supplied into the fuel cell. Thereby, since it is not necessary to divide and supply to several fuel gas manifolds, the supply amount of fuel gas does not become non-uniform | heterogenous. As a result, uneven fuel gas supply to the fuel cells can be eliminated. Therefore, adverse effects on the performance and durability of the fuel cell can be reduced. The cost can be reduced because a plurality of complicated pipes can be eliminated.

The fuel cell according to claim 2 further includes, in claim 1, the cell stack assembly is divided into a left cell stack group and a right cell stack group at the center in the left-right direction, and each includes the same number of cell stacks. In other words, the cell stack aggregate has an even number of cell stacks in total. A forward case extends above one of the cell stack groups, and a return case extends above the other cell stack group. Thereby, the upper part of the entire cell stack assembly can be covered with a substantially U-shaped reformer in a well-balanced manner, contributing to temperature maintenance in the power generation / combustion chamber and preventing temperature non-uniformity.

The fuel cell according to claim 3 is the fuel cell according to claim 2, wherein the number of cell stacks included in the cell stack assembly is two or four. That is, the left and right cell stack groups include one or two cell stacks, respectively. In practice, when 1 kW fuel cell, which is one of the most common capacities, is mounted on one fuel gas manifold, the length of the cell stack is increased in one row, and the overall shape of the fuel cell is extremely long. Since it is a rectangular parallelepiped, the heat dissipation area is increased, which is disadvantageous for heat independence. Therefore, when the total number of fuel cells is the same, the length can be reduced by using two rows and four rows, and the overall shape of the heat radiation area close to the minimum can be realized. This reduces heat dissipation.

The fuel cell according to claim 4 is the fuel cell according to any one of claims 1 to 3, wherein a part of the plurality of oxygen-containing gas introduction pipes hanging from the oxygen-containing gas chamber disposed above the power generation / combustion chamber is a forward case. Through the space between the return path case and the cell stack. In the present invention, since the forward case and the return case are interposed between the cell stack assembly and the ceiling in the power generation / combustion chamber, the location where the oxygen-containing gas introduction pipe is suspended from above is limited to some extent, but is substantially U-shaped. By utilizing the central space of the shaped reformer, a high-temperature oxygen-containing gas can be quickly introduced between the cell stacks.

The fuel cell according to claim 5 is the fuel cell according to claim 4, wherein another part of the plurality of oxygen-containing gas introduction pipes is inserted and disposed on the left and right outer sides of the cell stack assembly. That is, the oxygen-containing gas introduction pipe is inserted and disposed between the two cell stacks in the center and outside the cell stacks at the left and right ends. In the present invention, since the oxygen-containing gas introduction pipe is reduced, the cost is reduced.

The fuel cell according to claim 6 is the fuel cell according to claim 4 or 5, wherein the heat insulating material is arranged between the cell stacks in which the oxygen-containing gas introduction pipe is not inserted and arranged. Since the forward case or the backward case of the reformer extends above these cell stack groups, the oxygen-containing gas introduction pipe cannot be inserted and arranged. Therefore, by filling this empty space with a heat insulating material, it is possible to block the flow path of useless air passing between the cell stacks and promote the air flow between the fuel cells in one cell stack. In addition, by disposing a heat insulating material between the cell stacks, the cell stack itself can prevent reaction heat and Joule heat generated during power generation from escaping to the outside, thereby contributing to a heat independent operation.

-In the fuel cell which concerns on Claim 7, the vaporization part is provided in some reformers. By effectively using the heat of combustion above the cell stack assembly, it is possible to stably obtain the amount of heat for vaporization for generating steam necessary for reforming.

The fuel cell according to claim 8 is the fuel cell according to any one of claims 1 to 7, further comprising a fuel gas introduction case that is erected in communication with the fuel gas manifold at the front and rear end portions of the cell stack assembly. And a fuel gas transfer pipe connecting the return path case of the gasifier and the upper part of the fuel gas introduction case. That is, the fuel gas transfer pipe extends in the horizontal direction above the cell stack assembly. Therefore, the fuel gas reformed by the reformer is sufficiently heated while passing through the fuel gas transfer pipe, flows into the fuel gas introduction case, and descends in the fuel gas introduction case in the vertical direction. Flows into the manifold. The fuel gas introduction case is located in a corner where the temperature is likely to decrease in the power generation / combustion chamber. Therefore, there is an effect that the temperature of the surroundings is raised by the drop of the high-temperature fuel gas in the fuel gas introduction case. As a result, the temperature distribution in the power generation / combustion chamber is reduced, and the power generation efficiency is improved.

In the present invention, it is preferable that the forward case and the return case of the reformer have a box shape in which the thickness in the vertical direction is relatively thin compared to the width in the horizontal direction. By adopting such a shape, the reformer can be efficiently heated by the combustion gas that burns above the cell stack assembly.

Furthermore, it is preferable that the fuel gas introduction case standing in communication with the fuel gas manifold has a box shape that is relatively thin in the front-rear direction compared to the width in the left-right direction. By adopting such a shape, the fuel gas descends while uniformly diffusing over the entire width in the fuel gas introduction case. As a result, the fuel gas can be supplied almost uniformly to the wide fuel gas manifold, and as a result, uneven fuel gas supply to the fuel cells can be eliminated.

In addition, it is preferable that the fuel gas manifold has a box shape whose thickness in the vertical direction is relatively thin compared to the width in the horizontal direction. By adopting such a shape, since the volume of the fuel gas manifold is reduced, the volume of the entire power generation / combustion chamber is also reduced, which is advantageous in terms of heat self-support.

Hereinafter, embodiments will be described with reference to the drawings showing examples of fuel cells according to the present invention.
FIG. 1 is a longitudinal sectional view showing an embodiment of a fuel cell of the present invention. In the present specification, the left and right sides of the sheet of FIG. 1 are referred to as the left and right sides of the fuel cell 1, the directions are referred to as the left and right directions, and the direction perpendicular to the sheet is referred to as the front and rear direction. FIG. 2 is a perspective view schematically showing a power generation / combustion chamber provided at the center of the fuel cell of FIG.

  As shown in FIG. 1, the illustrated fuel cell 1 includes a housing 2 having a substantially rectangular parallelepiped shape. On the six surfaces forming the outer wall of the housing 2, a left outer heat insulating wall 3a, a right outer heat insulating wall 3b, an upper outer heat insulating wall 3c, a lower outer heat insulating wall 3d, and a front outer heat insulating wall (Fig. (Not shown) and a rear outer heat insulating wall (not shown) are provided. A power generation / combustion chamber 8 is provided in the center of the housing 2. The front outer heat insulating wall and / or the rear outer heat insulating wall are detachably or removably mounted, and can access the power generation / combustion chamber 8 for replacement and repair. As an example, the outer peripheral surface of each outer heat insulating wall may be covered with a metal plate cover.

  The fuel cell 1 in FIG. 1 has a generally symmetrical structure. The surroundings of the power generation / combustion chamber 8 are on the five surfaces excluding the upper side, the left inner heat insulating wall 4a, the right inner heat insulating wall 4b, the lower inner heat insulating wall 4c, and the front inner heat insulating wall (not shown) as appropriate heat insulating materials. ) And a rear inner heat insulating wall (not shown). An upper gas chamber case 41 is disposed above the power generation / combustion chamber 8 with a partition plate 46 interposed therebetween, and an upper gas chamber 42 is formed therein. Heat exchangers 70a and 70b are provided between the left inner heat insulating wall 4a and the left outer heat insulating wall 3a and between the right inner heat insulating wall 4b and the right outer heat insulating wall 3b, respectively. The upper ends of the two heat exchangers 70 a and 70 b are also partitioned from the upper gas chamber 42 via the partition plate 46. A bottom plate 40 is disposed between the lower inner heat insulating wall 4c and the lower outer heat insulating wall 3d.

  The two heat exchangers 70a and 70b have a rectangular parallelepiped hollow casing whose length in the up-down direction and the front-rear direction is longer than the width in the left-right direction, and has a bilaterally symmetric structure. The heat exchanger 70a will be described. The inside of the hollow housing is vertically divided by a vertical partition 74, and is divided into an outer inflow passage 75 and an inner discharge passage 76. An inflow portion 77 into which an oxygen-containing gas (for example, air) supplied from the outside flows is provided at the lower end of the inflow passage 75, and the combustion gas to be discharged to the outside is disposed at the lower end of the exhaust passage 76. A discharge unit 78 is provided for discharging from the discharge. Behind the heat exchanger 70a, a double cylindrical body 50 (only the upper end portion thereof is shown in FIG. 1) is provided that is elongated in the vertical direction. The inflow cylinder 54 inside the double cylinder 50 is connected to an inflow portion 77, and an oxygen-containing gas supply pipe (not shown) is connected. The discharge cylinder 52 outside the double cylinder 50 is connected to the discharge part 78 of the heat exchanger 70a.

  In each of the inflow path 75 and the discharge path 76 of the heat exchanger 70a, zigzag-shaped flow paths having six layers in the vertical direction are formed by five horizontal partition walls 73. For the inflow path 75, for example, the low-temperature oxygen-containing gas supplied from the outside and flowing into the heat exchanger 70a from the inflow portion 77 is zigzag from the back to the front in the first layer and from the front to the back in the second layer. And flows into the upper gas chamber 42 from an inflow opening 45 provided at the upper end of the sixth layer. On the other hand, for the discharge path 76, for example, the high-temperature combustion gas flowing into the sixth layer from the power generation / combustion chamber 8 through the discharge opening 72 flows in a zigzag manner from the rear to the front and from the front to the rear in the fifth layer. The heat exchanger 70a exits from the discharge portion 78 provided at the rear end of the first floor, and is discharged to the outside through the discharge cylinder 52. Accordingly, in this process, heat exchange is performed between the low-temperature oxygen-containing gas and the high-temperature combustion gas via the vertical partition 74, and as a result, the oxygen-containing gas is preheated. In this way, exhaust heat recovery from the combustion gas is performed.

  The oxygen-containing gas flowing into the upper gas chamber 42 is introduced into the power generation / combustion chamber 8 through the three oxygen-containing gas introduction pipes 43a, 43b, 43c. The upper ends of the oxygen-containing gas introduction pipes 43a, 43b, 43c are respectively attached to oxygen-containing gas introduction pipe assembly fittings 47a, 47b, 47c fixed on the partition plate 46 and open into the upper gas chamber 42. On the other hand, the lower end hangs down into the power generation / combustion chamber 8 and opens. Oxygen-containing gas is released from this lower end. Further, the periphery of the oxygen-containing gas introduction pipes 43a, 43b, 43c is covered with appropriate heat insulating materials 5a, 5b, 5c. Thereby, deterioration by the heat | fever of the oxygen containing gas introduction pipes 43a, 43b, and 43c inserted in a high temperature combustion area | region can be prevented. Details of the oxygen-containing gas introduction pipe will be described later with reference to FIG.

  One fuel gas manifold 61 is installed on the bottom surface in the power generation / combustion chamber 8. The fuel gas manifold 61 has a rectangular parallelepiped shape that extends long in the front-rear direction. Further, it is preferably a flat box shape whose thickness in the vertical direction is relatively thin compared to the width in the horizontal direction. On the top plate of the fuel gas manifold 61, four rows of cell stacks 30b, 30a, 31a, 31b that perform a power generation reaction are arranged at predetermined intervals in the left-right direction to form a cell stack aggregate. As shown in FIG. 2, each cell stack includes a plurality of fuel cells, and these are arranged at a predetermined interval in the front-rear direction. One fuel battery cell has a substantially flat plate shape elongated in the vertical direction. Details of the structure of the cell stack will be described later with reference to FIG.

  Each fuel cell is mounted on each slit formed on the top plate of the fuel gas manifold 61 so that the fuel gas is supplied from the fuel gas manifold 61. In the illustrated example, two fuel gas chambers 62a and 62b are provided in the fuel gas manifold 61. The fuel gas chamber 62a supplies the fuel gas to the two left cell stacks 30a and 30b, and the fuel gas chamber 62b supplies fuel gas to the two cell stacks 31a and 31b on the right side. As another example, communication holes of an appropriate number and shape may be formed in the partition wall between the two fuel gas chambers 62a and 62b. In this case, the fuel gas distribution is further improved.

  Furthermore, the reformer 10 is provided above the cell stack assembly. The reformer 10 plays a role of reforming a gas to be reformed supplied from the outside into a hydrogen-rich fuel gas to form a fuel gas and sending it to the fuel gas manifold 61.

  The reformer 10 will be described with reference to FIG. The reformer 10 includes an outward path case 12 and a return path case 14 that are arranged in parallel with each other in a horizontal plane. Furthermore, it is a substantially U shape which comprises the connection case 13 which connects the end parts of the outward path case 12 and the return path case 14. Therefore, a central space with an appropriate interval exists between the forward case 12 and the backward case 14. The forward case 12 of the reformer 10 is preferably located above the two left cell stacks 30a and 30b, while the return case 14 is preferably located above the two right cell stacks 31a and 31b. . The connection case is located above the rear end side of the cell stack assembly. The connection case 13 is attached to and supported by the upper end of a support 17 fixed to the bottom of the power generation / combustion chamber 8. The reformer 10 is held at a predetermined position by a support 17 to which the connection case 13 is attached and a fuel gas introduction case 16 described later.

  Preferably, as shown in FIG. 2, the forward case 12 and the return case 14 have a rectangular parallelepiped shape extending long in the front-rear direction, and a flat box shape having a relatively thin vertical thickness compared to the width in the left-right direction. is there. A reformed gas supply pipe 11 and a water supply pipe 19 are connected to the front end face of the forward case 12, and the gas to be reformed and water are supplied by these. The reformed gas may be a hydrocarbon gas such as city gas. The supplied gas flows in the forward case 12 of the reformer 10 from the front to the rear, passes through the connection case 13, and flows from the rear to the front in the return case 14. That is, as shown by a broken line arrow in the figure, the gas flows so as to draw a U shape.

  In FIG. 2, the oxygen-containing gas introduction pipe is omitted, but the central oxygen-containing gas introduction pipe 43 b in FIG. 1 is a space between the forward case 12 and the return case 14 of the substantially U-shaped reformer 10. Inserted through. Further, the left and right oxygen-containing gas introduction pipes 43a and 43c in FIG. 1 are respectively inserted and arranged on the left and right outer sides of the cell stack assembly.

  Generally, the cell stack aggregate in the present invention is formed by arranging a plurality of cell stacks in the left-right direction. At the same time, the cell stack aggregate is preferably composed of a left cell stack group and a right cell stack group each including the same number of cell stacks. That is, the preferred cell stack assembly of the present invention includes an even number of cell stacks. The forward case 12 of the reformer 10 extends above one of the cell stack groups, and the return case 14 of the reformer 10 extends above the other cell stack group. In the example of FIGS. 1 and 2, the cell stack aggregate includes four cell stacks, but is not limited thereto. Furthermore, as another embodiment, the number of cell stacks included in each of the left cell stack group and the right cell stack group may not necessarily be the same. For example, three on the left side and two on the right side.

  Further, as shown in FIG. 2, one end of a fuel gas transfer pipe 15 extending in the front-rear direction is connected to the front end surface of the return case 14. The other end of the fuel gas transfer pipe 15 is connected to the upper part of a rectangular parallelepiped fuel gas introduction case 16 extending in the vertical direction.

  The fuel gas introduction case 16 is erected on the fuel gas manifold 61. The fuel gas introduction case 16 has a flat box shape in which the thickness in the front-rear direction is smaller than the width in the left-right direction. The width in the left-right direction is almost half of the width of the fuel gas manifold 61 in the illustrated example. Also good. The lower end 16 a of the fuel gas introduction case 16 communicates with the fuel gas manifold 61, for example, stands on a communication hole 61 b formed in a part of the top plate 61 a of the fuel gas manifold 61.

  Therefore, the fuel gas delivered from the reformer 10 flows into the fuel gas introduction case 16 through the fuel gas transfer pipe 15, descends in the vertical direction as shown by the arrow, and flows into the fuel gas manifold 61. . The fuel gas descends while uniformly diffusing over the entire width of the fuel gas introduction case 16. The fuel gas that has flowed into the fuel gas manifold 61 flows into each fuel gas chamber as indicated by arrows.

  FIG. 3 is a cross-sectional view taken along the line A in FIG. 2 and shows an example of a cross section of the reformer 10. The gas chamber 12a formed in the forward case 12 of the reformer 10 is provided with a hollow vaporization portion 12b on the inflow side of the gas to be reformed and water. In the vaporization section 12b, water is converted into steam, and the steam is mixed with the reformed gas. The amount of heat of the combustion gas is used as the heat of vaporization at this time. The vaporization part 12b is filled with heat-resistant spheres such as zirconia spheres, for example, and the steam and the reformed gas are sufficiently mixed and preheated by the turbulent flow generated when the gas flows through the gaps between the spheres. Subsequently, the gas flows through the gas chamber 13 a in the connection case 13 and flows into the return case 14. A gas chamber 14a formed in the return case 14 contains a reforming catalyst 14b and is reformed into a hydrogen-rich fuel gas. Then, the fuel gas delivered from the return case 14 flows into the fuel gas introduction case 16 through the fuel gas transfer pipe 15 and descends. In the figure, broken line arrows indicate the flow of the reformed gas or fuel gas and water or steam.

  FIG. 4 is a B cross-sectional view of FIG. 2 and shows an example of a cross section of the fuel gas manifold 61. A fuel gas introduction chamber 62 c is provided near the front end of the fuel gas manifold 61. A communication hole with the fuel gas introduction case is provided in a part of the ceiling of the fuel gas introduction chamber 62c. The fuel gas introduction chamber 62c and the fuel gas chambers 62a and 62b communicate with each other through fuel gas introduction ports 63a and 63b, respectively. The fuel gas introduction chamber 62c serves as a buffer chamber that alleviates the non-uniformity of the flow of the fuel gas, and the uniformized fuel gas flows equally into the fuel gas chambers 62a and 62b. In the figure, broken line arrows indicate the flow of fuel gas. As another example, communication holes of an appropriate number and shape may be formed in the partition wall between the two fuel gas chambers 62a and 62b. In this case, since the fuel gas can flow between the two fuel gas chambers 62a and 62b, the fuel gas distribution is further improved.

  FIG. 5 is an exploded perspective view showing an example of a mounting form of the oxygen-containing gas introduction pipe of the fuel cell of FIG. In FIG. 5, the illustration of the fuel gas introduction case 16 in FIG. 2 is omitted so that the four cell stacks 30a to 31b appear. Referring also to FIG. 1, the partition plate 46 is interposed between the power generation / combustion chamber 8 and the upper gas chamber 42, and has openings 48 a through which the three oxygen-containing gas introduction pipes 43 a, 43 b, 43 c are passed. 48b and 48c. Inlet openings 45 communicating with the heat exchangers are also formed in the left and right ends of the partition plate 46, respectively.

  As shown in FIG. 5, for example, the oxygen-containing gas introduction tube 43a is formed as an assembly in which a plurality of tubes are arranged in a line in the front-rear direction, and the upper end of each tube is drilled in a flat plate-like assembly fitting 47a. Are attached to the plurality of attachment holes. Moreover, the several pipe body arranged in a row is penetrated in one rectangular parallelepiped heat insulating material 5a. The assembly fitting 47a is fixed on the upper surface of the partition plate 46 with the oxygen-containing gas introduction pipe 43a passed through the opening 48a. The same applies to the other oxygen-containing gas introduction pipes 43b and 43c. In the assembled state, the two oxygen-containing gas introduction pipes 43a and 43c on both sides are disposed outside the cell stacks 30b and 31b on the left and right sides of the cell stack assembly. On the other hand, the central oxygen-containing gas introduction pipe 43b is disposed between the central cell stacks 30a and 31a through the central space of the substantially U-shaped reformer 10. In the above embodiment, the oxygen-containing gas is supplied from the upper side to the lower side by introducing the oxygen-containing gas 43a, etc., but the oxygen-containing gas is supplied from the bottom side of the power generation / combustion chamber 8, that is, from the lower side to the upper side. You may make it do.

  Refer to FIG. 1 again. When oxygen-containing gas introduction pipes are not inserted between the cell stacks arranged in the left-right direction, for example, between the cell stacks 30a and 30b and between the cell stacks 31a and 31b, the heat insulating material 6a, 6b are respectively arranged. Since there is the forward case 12 or the return case 14 of the reformer 10 above the cell stack, the oxygen-containing gas introduction pipe cannot be suspended from above. By closing such a space with the heat insulating materials 6a and 6b, it is possible to prevent an inconvenient air flow and prevent heat dissipation. FIG. 6B is a perspective view showing an example of the shape of the heat insulating materials 6a and 6b. The portion inserted between the cell stacks has a flat plate shape having the same thickness as the space between the cell stacks, and extended portions 6a1 and 6b1 extending downward are provided at the rear end portions. By this extended portion, the flow of air in the left-right direction on the rear surface side of the fuel gas manifold 61 can be blocked.

  FIG. 7 shows another embodiment of the fuel cell of the present invention. In the embodiment of FIG. 1 described above, the cell stack assembly includes four cell stacks. However, in the fuel cell 1a of FIG. 7, the cell stack assembly includes two cell stacks 30a and 31a. In this case, the forward case 12 of the reformer 10 extends above the left cell stack 30a, and the return case 14 extends above the right cell stack 31a.

  If the cell stack assembly of FIG. 7 includes the same number of fuel cells as the embodiment of FIG. 1, the cell stack assembly of the fuel cell 1a of FIG. 7 is the cell stack assembly of the fuel cell 1 of FIG. Longer in the front-rear direction. Further, since there is only one cell stack on each of the left and right, the heat insulating material between the cell stacks shown in FIG. 6A is not provided. Other components are the same as those of the fuel cell 1 of FIG.

  As described above, in the present invention, the left-side cell stack group including the same number of cell stacks because the substantially symmetrical U-shaped reformer is disposed above the cell stack assembly. And a right cell stack group. However, the number of cell stacks included in the cell stack aggregate is not limited to two or four shown in the embodiment.

  Here, for reference, an example of the configuration of the cell stack in the embodiment of the present invention is shown with reference to FIG. FIG. 8 is a cross-sectional view of the cell stack 30a shown in FIG. 1, for example. Each fuel cell 32 includes an electrode support substrate 33, a fuel electrode layer 34 that is an inner electrode layer, a solid electrolyte layer 35, an oxygen electrode layer 36 that is an outer electrode layer, and an interconnector 37. The electrode support substrate 33 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 33 is formed with a plurality (four in the illustrated example) of fuel gas passages 38 penetrating the electrode support substrate 33 in the vertical direction. Each of the electrode support substrates 33 is disposed so as to correspond to, for example, a slit provided on the upper surface of the fuel gas manifold, and is joined by a ceramic adhesive having excellent heat resistance. The fuel gas is sent to the fuel gas passage 38 through this slit.

  The interconnector 37 is disposed on one side of the electrode support substrate 33. The fuel electrode layer 34 is disposed on the other surface and both side surfaces of the electrode support substrate 33, and both ends thereof are joined to both ends of the interconnector 37. The solid electrolyte layer 35 is disposed so as to cover the entire fuel electrode layer 34, and both ends thereof are joined to both ends of the interconnector 37. The oxygen electrode layer 36 is disposed on the main portion of the solid electrolyte layer 35, that is, on the portion covering the other surface of the electrode support substrate 33, and is located at a position facing the interconnector 37 with the electrode support substrate plate 33 interposed therebetween.

  A current collecting member 39 is disposed between adjacent fuel cells 32 in the cell stack 30a, and connects the interconnector 37 of one fuel cell 32 and the oxygen electrode layer 36 of the other fuel cell 32. ing. Current collecting members are disposed on both ends of the cell stack 30a, that is, on one side and the other side of the cell located at the upper end and the lower end in FIG. Electric power extraction means (not shown) is connected to the current collecting members located at both ends of the cell stack, and such electric power extraction means penetrates the housing and extends out of the housing.

  With reference to FIGS. 1 and 2 again, a process during power generation in the fuel cell of the present invention will be described. In the fuel cell 1 as described above, after the reformed gas is supplied to the reformer 10 via the reformed gas supply pipe 11 and reformed into hydrogen-rich fuel gas in the reformer 10. The fuel gas is supplied to the fuel gas chambers 62a and 62b defined in the fuel gas manifold 61 through the fuel gas transfer pipe 15 and the fuel gas introduction case 16, and then supplied to the cell stack.

On the other hand, oxygen-containing gas, which may be air, is supplied from the inflow cylinder 54 of the double cylinder 50 through the inflow portion 77 to the inflow path 75 of the heat exchanger 71, and then from the upper gas chamber 42 to the oxygen-containing gas introduction pipe 43a. The fuel is injected in the power generation / combustion chamber 8 by such means. In each of the cell stacks 30a to 31b, 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 not used for power generation in the cell stacks 30a to 31b flow above the power generation / combustion chamber 8 and are ignited by ignition means (not shown) disposed at appropriate positions. Burned. As is well known, the temperature in the power generation / combustion chamber 8 becomes high, for example, about 700 to 1000 ° C. due to the power generation in the cell stack and also due to the combustion of the fuel gas and the oxygen-containing gas. Then, the combustion gas flows into the discharge path 76 of the heat exchanger 71 through the discharge opening 72 that opens near the ceiling surface of the power generation / combustion chamber 8. Then, it is discharged from the discharge cylinder 52 through the discharge portion 78.

  In such a power generation process, the reformer 10 is disposed in the power generation / combustion chamber 8 and is located immediately above the cell stacks 30a to 30d. The high temperature generated in the combustion chamber 8 is effectively used for reforming the reformed gas.

  The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings. However, the present invention is not limited to these embodiments, and various modifications and changes can be made without departing from the scope of the present invention. Correction is possible.

It is a longitudinal cross-sectional view which shows the Example of the fuel cell of this invention. FIG. 2 is a perspective view schematically showing a power generation / combustion chamber which is a part of the fuel cell of FIG. 1. It is A sectional drawing of FIG. It is B sectional drawing of FIG. It is a disassembled perspective view which shows the mounting form of the oxygen containing gas introduction pipe | tube of the fuel cell of FIG. It is a perspective view which shows the mounting | wearing form of the heat insulating material in the electric power generation and combustion chamber of the fuel cell of FIG. It is a whole perspective view of the heat insulating material of FIG. 6A. It is a longitudinal cross-sectional view which shows the other form of the fuel cell of this invention. It is sectional drawing which shows the cell stack of FIG. It is a perspective view which abbreviate | omits and shows the form of the conventional fuel cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Housing 6a, 6b Thermal insulation material between cell stacks 8 Power generation / combustion chamber 10 Reformer 11 Reformed gas supply pipe 12 Outward case 12a Gas chamber 12b Evaporation part 12c Reforming catalyst 13 Connection case 13a Gas chamber 14 Return path Case 14b Reforming catalyst 15 Fuel gas transfer pipe 16 Fuel gas introduction case 19 Water supply pipe 30a, 30b, 31a, 31b Cell stack 32 Fuel cell 42 Upper gas chamber 43a, 43b, 43c Oxygen-containing gas introduction pipe 61 Fuel gas manifold

Claims (8)

In a power generation / combustion chamber provided in the housing, a cell stack assembly in which a plurality of solid oxide fuel cells are arranged in a line in the front-rear direction, a plurality of cell stacks arranged in the left-right direction, and
One fuel gas manifold mounted with each fuel cell to supply fuel gas to each fuel cell of the cell stack assembly;
A reformer provided above the cell stack assembly,
The reformer is substantially U-shaped and includes a forward case and a backward case disposed in parallel with each other in a horizontal plane, and a connecting case that connects ends of the forward case and the backward case. A fuel cell characterized in that a reforming catalyst is accommodated in part, a gas to be reformed is supplied to the forward case, and a fuel gas is sent from the return case.   The cell stack aggregate is composed of a left cell stack group and a right cell stack group each including the same number of the cell stacks, and the forward case extends in the front-rear direction above any one of the cell stack groups, 2. The fuel cell according to claim 1, wherein the return case extends in the front-rear direction above the other cell stack group. The fuel cell according to claim 2, wherein the number of cell stacks included in the cell stack assembly is two or four.   A plurality of oxygen-containing gas introduction pipes hanging from the oxygen-containing gas chamber disposed above the power generation / combustion chamber into the power generation / combustion chamber, wherein a part of the plurality of oxygen-containing gas introduction pipes is the forward case The fuel cell according to any one of claims 1 to 3, wherein the fuel cell is inserted between the cell stacks and passes between the return path case and the return path case. 5. The fuel cell according to claim 4, wherein another part of the plurality of oxygen-containing gas introduction pipes is inserted and arranged on each of the left and right outer sides of the cell stack assembly. 6. The fuel cell according to claim 4, wherein a heat insulating material is disposed between the cell stacks in which the oxygen-containing gas introduction pipe is not inserted and disposed.   The fuel cell according to claim 1, wherein a vaporization unit is provided in a part of the reformer. A fuel gas introduction case erected in communication with the fuel gas manifold at the front-rear direction end of the cell stack assembly;
The fuel cell according to claim 1, further comprising a fuel gas transfer pipe that connects the return case of the reformer and an upper portion of the fuel gas introduction case.

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