JP2006032328A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a desirable manifold structure capable of uniformly supplying gas to each power generating cell and always presenting a stable power generating property for each power generating cell. <P>SOLUTION: The fuel cell is equipped with a fuel cell stack structured by laminating a plurality of power generation cells and separators alternately, and gas manifolds 15, 16 distributing gas for reaction to each separator provided in a laminated direction of the power generation cells and the separators. The manifolds 15, 16 have single-tube structures provided with gas supplying holes 25 on a peripheral wall, and also, a gas dispersion board 23 with a number of gas introduction holes 24 formed is placed in a longitudinal direction in a tube 18. The inner part of the tube 18 is separated into a gas introduction area 26 introducing the gas and a gas distribution area 27 distributing the introduction gas through the gas supplying hole 25. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a manifold for flat plate fuel cells, and more particularly to a manifold structure for supplying gas evenly to each separator.

A solid oxide fuel cell having a laminated structure in which a solid electrolyte layer made of an oxide ion conductor is sandwiched between an air electrode layer (oxidant electrode layer) and a fuel electrode layer is a third generation fuel cell for power generation. Development is progressing. In a solid oxide fuel cell, oxygen (air) is supplied to the air electrode side, and fuel gas (H ₂ , CO, etc.) is supplied to the fuel electrode side. The air electrode and the fuel electrode are both porous so that the gas can reach the interface with the solid electrolyte.

Oxygen supplied to the air electrode side passes through the pores in the air electrode layer and reaches the vicinity of the interface with the solid electrolyte layer. At this part, it receives electrons from the air electrode and converts them into oxide ions (O ²⁻ ). Ionized. The oxide ions diffuse and move in the solid electrolyte layer toward the fuel electrode. The oxide ions that have reached the vicinity of the interface with the fuel electrode react with the fuel gas at this portion to generate a reaction product (H ₂ O, CO _2, etc.), and discharge electrons to the fuel electrode.

The electrode reaction when hydrogen is used as the fuel is as follows.
Air electrode: 1/2 O ₂ + 2e ⁻ → O ²⁻
Fuel electrode: H ₂ + O ²⁻ → H ₂ O + 2e ⁻
Overall: H ₂ +1/2 O ₂ → H ₂ O

  The solid electrolyte layer is a moving medium for oxide ions and also functions as a partition wall for preventing direct contact between the fuel gas and air, and thus has a dense structure that is impermeable to gas. This solid electrolyte layer should have a high oxide ion conductivity, be chemically stable under conditions from the oxidizing atmosphere on the air electrode side to the reducing atmosphere on the fuel electrode side, and be made of a material that is resistant to thermal shock. There is generally used stabilized zirconia (YSZ) to which yttria is added as a material satisfying such requirements.

On the other hand, both the air electrode (cathode) layer and the fuel electrode (anode) layer, which are electrodes, must be made of a material having high electron conductivity. Since the air electrode material must be chemically stable in a high-temperature oxidizing atmosphere around 700 ° C., the metal is inappropriate, and a perovskite-type oxide material having electron conductivity, specifically LaMnO ₃ Alternatively, LaCoO ₃ or a solid solution in which a part of these La is substituted with Sr, Ca or the like is generally used. The fuel electrode material is generally a metal such as Ni or Co, or a cermet such as Ni—YSZ or Co—YSZ.

  Solid oxide fuel cells include a high-temperature operation type that operates at a high temperature of about 1000 ° C. and a low-temperature operation type that operates at a low temperature of about 700 ° C. A low temperature operation type solid oxide fuel cell, for example, stabilizes the thickness of stabilized zirconia (YSZ) added with yttria as an electrolyte to a thickness of about 10 μm to reduce the resistance of the electrolyte, and generates electricity as a fuel cell even at low temperatures. So that the improved power generation cell is used.

In a high-temperature solid oxide fuel cell, ceramics having electronic conductivity such as lanthanum chromite (LaCrO ₃ ) is used as a separator. In a low-temperature operation type solid oxide fuel cell, a metal such as stainless steel is used. Material can be used.

  Three types of solid oxide fuel cell structures have been proposed: a cylindrical type, a monolith type, and a flat plate type. Among these structures, since a metal separator can be used for a low temperature operation type solid oxide fuel cell, a flat plate type structure that is easy to give a shape to the metal separator is suitable.

  A stack of flat plate type solid oxide fuel cells has a structure in which power generation cells, current collectors, and separators are alternately stacked. A pair of separators sandwich the power generation cell from both sides, one being in contact with the air electrode via the air electrode current collector and the other being in contact with the fuel electrode via the fuel electrode current collector. A sponge-like porous body such as a Ni-based alloy can be used for the fuel current collector, and a similar sponge-like porous body such as an Ag-based alloy can be used for the air electrode current collector. it can. A sponge-like porous body has a current collecting function, a gas permeation function, a uniform gas diffusion function, a cushion function, a thermal expansion difference absorption function, and the like, and is therefore suitable as a multifunctional current collector material.

  The separator has a function of electrically connecting the power generation cells and supplying gas to the power generation cells. The fuel is introduced from the outer peripheral surface of the separator and discharged from the surface facing the separator fuel electrode layer. A passage and an oxidant passage which introduces an oxidant gas from the outer peripheral surface of the separator and discharges the gas from a surface facing the oxidant electrode layer of the separator are provided.

  Also, on the side of the fuel cell stack, a fuel manifold that supplies fuel gas through the connection pipe to the fuel gas passage of each separator, and oxidant gas (air) through the connection pipe to the oxidant gas passage of each separator And an oxidizing agent manifold extending in the stacking direction of the power generation cells.

Normally, the above-described fuel manifold and oxidizer manifold have an elongated single pipe structure (single pipe structure) in which a large number of connecting pipes drawn from each separator are connected to the pipe wall, and are introduced from the gas inlet. A reaction gas is supplied to each separator from the internal space of the manifold through these connection pipes.
Such a gas supply mechanism is called an external manifold. Besides this, an internal manifold is also known in which a manifold mechanism is provided in the fuel cell stack and gas is supplied directly to the separator regardless of the connecting pipe.

However, in the case of the manifold structure described above, even in the same pipe, there is a difference in the gas flow conditions (gas pressure) between the connection pipe close to the gas inlet of the manifold and the connection pipe far from the gas inlet. There was a problem that the amount was not uniform and the power generation performance varied.
In order to avoid such a problem, proposals for equalizing the amount of gas supplied to each power generation cell have been made conventionally. For example, Patent Documents 1 to 3 are disclosed.
JP-A-8-293318 JP 2000-58087 A JP 2002-358996 A

  However, at present, it is difficult to obtain sufficient uniformity in the gas flow in the manifold, and the gas rectifying mechanism for that purpose is complicated, resulting in a cost increase. For this reason, the appearance of a manifold having a more preferable rectifying mechanism that can supply gas evenly to each power generation cell is desired.

  The present invention has been made in view of such demands, and is a flat plate having a preferable manifold that can supply gas evenly to each power generation cell and each power generation cell can always exhibit stable power generation characteristics. An object of the present invention is to provide a stacked fuel cell.

  That is, according to the present invention, the fuel cell stack configured by alternately stacking a plurality of power generation cells and separators, and the reaction gas provided in the stacking direction of the power generation cells and separators are distributed to each separator. In the flat stack type fuel cell provided with the gas manifold, the manifold has a single tube structure in which a gas supply hole is provided in the peripheral wall, and a gas in which a number of gas introduction holes are formed in the longitudinal direction in the tube. Dispersion plates are provided, and the inside of the pipe is divided into a gas introduction space into which gas is introduced and a gas distribution space into which the introduced gas is distributed through the gas supply holes.

  In this configuration, since the gas introduction space partitioned by the gas dispersion plate functions as a gas accumulation space, the introduced gas is introduced into the gas distribution space with a uniform gas pressure from the gas introduction hole of the gas dispersion plate. Become. Thereby, the gas supply amount supplied to each separator through a gas supply hole can be equalized, and the nonuniformity of the characteristic of each power generation cell can be reduced. Further, the gas can be supplied to the tube body at an arbitrary position such as an end portion or a central portion.

  According to a second aspect of the present invention, there is provided a flat plate type fuel cell according to the first aspect, wherein a gas introduction nozzle is provided in the gas introduction space so that a tip portion thereof faces the gas dispersion plate. It is arranged, and a plurality of nozzle holes are formed in at least a peripheral wall of the nozzle.

  In this configuration, by ejecting the gas from the peripheral wall of the nozzle, the ejected gas is prevented from passing directly through the gas introduction hole of the gas dispersion plate and is diffused into the gas introduction space. Thereby, the gas accumulation effect in the gas introduction space is further improved, and the gas pressure in the gas distribution space is further equalized.

  According to a third aspect of the present invention, there is provided a fuel cell stack configured by alternately stacking a plurality of power generation cells and separators, and a reaction gas provided in the stacking direction of the power generation cells and separators to each separator. In a flat plate type fuel cell provided with a gas manifold for distribution, the manifold includes an outer tube having a gas supply hole in a peripheral wall, and an inner tube which is disposed in the outer tube and serves as a gas introduction space into which gas is introduced. And a plurality of gas introduction holes are formed in the peripheral wall of the inner tube.

  In this configuration, since the space portion of the inner tube functions as a gas accumulation space, the introduced gas is introduced into the outer tube with a uniform gas pressure from the gas introduction hole of the inner tube. Thereby, the gas supply amount supplied to each separator through a gas supply hole can be equalized, and the nonuniformity of the characteristic of each power generation cell can be reduced. Further, the gas can be supplied to the inner pipe at an arbitrary position such as an end portion or a central portion.

  According to a fourth aspect of the present invention, in the flat plate type fuel cell according to any one of the first to third aspects, the position of the gas introduction hole and the position of the gas supply hole are in the stacking direction. And / or a deviation in a direction perpendicular to the stacking direction.

  In this configuration, since the gas accumulation effect is obtained even in the space between the gas introduction hole and the gas supply hole, the gas introduced through the gas introduction hole is diffused into the space by this accumulation effect, and the gas pressure is equalized. It becomes. Thereby, the gas supply amount supplied to each separator through the gas supply hole can be made even more uniform, and the unevenness of the characteristics of each power generation cell can be reduced.

  According to a fifth aspect of the present invention, in the flat plate type fuel cell according to any one of the first to fourth aspects, the number of the gas introduction holes is two or more, The cross-sectional areas of the introduction holes are equal, each is arranged at equal intervals in the longitudinal direction, and the gas flow velocity flowing through each gas introduction hole is larger than the gas flow velocity flowing through the gas introduction space.

  In this configuration, the number of holes and the cross-sectional area thereof may be arbitrarily set as long as the orifice effect by the gas introduction hole is obtained.

  According to a sixth aspect of the present invention, in the flat plate type fuel cell according to any one of the first to fourth aspects, the cross-sectional area of the gas introduction hole advances downstream of the gas flow. It is characterized by the fact that it is greatly formed.

  In this configuration, the gas pressure in the space between the gas introduction hole and the gas supply hole can be equalized, and the gas supply amount supplied to each separator through the gas supply hole can be further equalized.

  As described above, according to the present invention, in a flat plate type fuel cell equipped with a gas manifold, a gas rectifying mechanism using a gas dispersion plate and a rectifier pipe is provided inside the manifold, so that the distribution from the manifold to each separator. The amount of gas supplied can be made uniform, the non-uniformity of the characteristics of each power generation cell can be reduced, and the power generation characteristics of the fuel cell can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First, the overall configuration of a solid oxide fuel cell to which the present invention is applied will be described with reference to FIGS. FIG. 8 is an exploded cross-sectional view showing the main part of the fuel cell, and FIG. 9 is an exploded perspective view of the main part.
In the figure, reference numeral 1 denotes a fuel cell stack. The fuel cell stack 1 includes a power generation cell 5 in which a fuel electrode layer 3 and an air electrode layer (oxidant electrode layer) 4 are arranged on both surfaces of a solid electrolyte layer 2, and a fuel electrode current collector 6 outside the fuel electrode layer 3. And an air electrode current collector (oxidant electrode current collector) 7 outside the air electrode layer 4 and a separator 8 outside the current collectors 6 and 7 are sequentially stacked.

Here, the solid electrolyte layer 2 is made of stabilized zirconia (YSZ) or the like to which yttria is added, and the fuel electrode layer 3 is made of a metal such as Ni or Co or a cermet such as Ni—YSZ or Co—YSZ. The air electrode layer 4 is made of LaMnO ₃ , LaCoO ³ or the like, the fuel electrode current collector 6 is made of a sponge-like porous sintered metal plate such as a Ni-based alloy, and the air electrode current collector 7 is made of The separator 8 is made of stainless steel or the like, and is made of a sponge-like porous sintered metal plate such as an Ag-based alloy.

  The separator 8 has a function of electrically connecting the power generation cells 5 and supplying gas to the power generation cells 5. A fuel gas is introduced into the separator 8 from the outer peripheral surface of the separator 8, and the fuel of the separator 8. A fuel gas passage 11 that is discharged from the substantially central portion of the surface facing the electrode current collector 6 and an oxidant gas introduced from the outer peripheral surface of the separator 8 and discharged from the surface of the separator 8 facing the air electrode current collector 7. An oxidant gas passage 12 is provided. However, the separators 8 (8A, 8B) at both ends have only one of the gas passages 11, 12.

  Further, on the side of the fuel cell stack 1, as shown in FIG. 8, as shown in FIG. 8, a fuel manifold 15 for supplying fuel gas to the fuel gas passage 11 of each separator 8 through a connection pipe 13, and an oxidant gas for each separator 8 An oxidant manifold 16 for supplying an oxidant gas (air) to the passage 12 through the connection pipe 14 extends in the stacking direction of the power generation cells 5.

  By the way, the fuel manifold and the oxidant manifold according to the present invention are provided with a gas rectifying mechanism for the gas introduced into the pipe, unlike the conventional manifold consisting of only a single pipe.

  The details of the embodiment of the external manifold will be described below with reference to FIGS. The fuel manifold 15 and the oxidant manifold 16 have the same structure, and only the reaction gas introduced into the pipe is different between the fuel gas and the oxidant gas (air). .

FIG. 1 shows a first embodiment of an external manifold structure according to the present invention.
The manifolds 15 and 16 shown in FIG. 1 are composed of a rectangular column-shaped single pipe 18 whose both ends are closed and a large number of gas supply holes 25 are provided on the peripheral wall, and each of these gas supply holes 25 is connected to a separator. A tube 13 (14) is connected.

Such a structure is the same as that of a conventional external manifold, but in the case of this embodiment, a metal gas distribution plate 23 having a large number of gas introduction holes 24 drilled in the center of the pipe is disposed in the longitudinal direction. The inside of the pipe is divided into a gas introduction space 26 into which an external gas is introduced, and a gas distribution space 27 in which the introduced gas is distributed and supplied to each separator 8 from the gas supply hole 25 through the connection pipe 13 (14). ing.
The gas introduction hole 24 is a fine hole having a hole diameter of about 1 mm, and is formed in a vertically aligned state at a predetermined interval in the approximate center of the gas dispersion plate 23 having an elongated rectangular shape. The number of the gas introduction holes 24 is the same as the number of the gas supply holes 25 of the pipe body 18, that is, the number of connecting pipes 13 (14). The disposition position of the gas dispersion plate 23 is not limited to this, and is arbitrarily set as long as a pressure difference (orifice effect) can occur between the upstream side and the downstream side of the gas introduction hole 24 with the gas dispersion plate 23 as a boundary. It doesn't matter.

In the gas introduction space 26, a gas supply pipe 20 to which a gas from the outside is supplied is connected to a substantially central portion in the longitudinal direction of the pipe side wall facing the gas dispersion plate 23. A tubular nozzle 21 is arranged so that 21 a faces the gas dispersion plate 23. Then, four nozzle holes 22 are formed at intervals of 90 degrees on the peripheral wall 21b of the nozzle 21 protruding into the pipe.
The nozzle 21 does not have the nozzle hole 22 on the tip surface 21a. However, when the nozzle hole 22 is also provided on the tip surface 21a of the nozzle 21, it is preferable to make the hole diameter smaller than the nozzle hole 22 of the peripheral wall 21b. This is to reduce the amount of gas ejected to the gas dispersion plate 23.

  On the other hand, in the gas distribution space 27, the connection pipe 13 (14) is connected to a gas supply hole 25 provided in the side wall of the pipe body 18 facing the gas dispersion plate 23. In the positional relationship between the gas introduction hole 24 and the gas supply hole 25 of the gas dispersion plate 23, as shown in FIG. 2A, both coincide in the vertical direction, but as shown in FIG. As described above, there is a deviation in the lateral direction.

  In the manifold 15 (16) having the above-described configuration, the gas dispersion plate 23 is provided so that the gas introduction space 26 in the pipe functions as a gas accumulation space, and the gas ejected from the nozzle 21 temporarily enters the gas introduction space 26. The gas is accumulated and pressurized, and is introduced into the gas distribution space 27 from the gas introduction hole 24 of the gas dispersion plate 23 with a substantially uniform gas pressure. At this time, the flow velocity of the gas passing through each gas introduction hole 24 is larger than the flow velocity of the gas flowing through the gas introduction space 26, and the above-described orifice effect is obtained. Thereby, the gas supply amount supplied to each separator 8 from each connection pipe 13 (14) is equalized, and as a result, the nonuniformity of the characteristics of each power generation cell 5 is reduced and the overall power generation characteristics of the fuel cell are obtained. Can be improved.

  In addition, when gas is supplied from the outside to the manifolds 15 and 16, the gas is ejected directly from the peripheral wall 21 b of the nozzle 21 in the vertical and horizontal directions in the gas introduction space 26, so that the gas to be ejected is directly from the gas dispersion plate 23. It is prevented from passing through the introduction hole 24 and diffuses into the gas introduction space 26. Thereby, the gas accumulation effect in the gas introduction space 26 is further improved, and the gas pressure in the gas distribution space 27 is further equalized.

  Further, by shifting the positions of the gas introduction hole 24 and the gas supply hole 25, the gas from the gas introduction hole 24 is prevented from reaching the connecting pipe 13 (14) directly. A gas accumulation effect similar to that of the space 26 can be obtained, and the gas introduced through the gas introduction hole 24 diffuses into the gas distribution space 27 as indicated by the arrow in FIG. The gas pressure is equalized. Thereby, since the gas supply amount supplied to each separator 8 through the gas supply hole 25 is further equalized, the nonuniformity of the characteristics of each power generation cell 5 can be reduced.

Next, FIG. 3 shows a second embodiment of the external manifold structure.
As shown in FIG. 3, the manifold 15 (16) of the present embodiment includes a rectangular columnar outer tube 19 that is closed at both ends and provided with a large number of gas supply holes 30 on the peripheral wall, and a substantially center in the outer tube 19. The inner pipe 28 (rectifying pipe 28) has a double structure which is arranged in the longitudinal direction in the section and has a large number of gas introduction holes 29 formed in the peripheral wall. The upper end of the rectifying pipe 28 is connected to the gas supply pipe 20 at the upper end of the outer pipe 19 and the lower end is closed. A connecting pipe 13 (14) is connected to each gas supply hole 30 of the outer pipe 19.

  As shown in FIG. 4, the gas introduction holes 29 are formed at three intervals in the circumferential direction of the rectifying pipe 28 excluding the connection pipe 13 (14) side, with an interval of 90 degrees. It is continuously drilled in the longitudinal direction with a predetermined interval. In this embodiment, the number of drill holes corresponds to the number of gas supply holes 30, that is, the number of connecting pipes 13 (14). Yes.

  In this configuration, the internal space of the rectifying pipe 28 into which the external gas is introduced (that is, the above-described gas introduction space) functions as a gas accumulation space, and the gas pressurized in this accumulation space is supplied to each gas introduction hole. 29, the gas is introduced into the outer tube 19 at a gas pressure that is more uniform. At this time, the flow velocity of the gas passing through each gas introduction hole 29 is larger than the flow velocity of the gas flowing in the rectifying pipe 28, and the above-described orifice effect is obtained also in this configuration. Thereby, the gas supply amount supplied to each separator 8 through the connecting pipe 13 (14) can be made uniform, and the power generation characteristics of the fuel cell can be improved by reducing the non-uniformity of the characteristics of each power generation cell 5. Can do.

  Further, the gas introduced into each manifold 15 (16) is jetted in three directions excluding the connection pipe side from the peripheral wall of the rectifying pipe 28, so that the gas ejected from the gas introduction hole 29 directly enters the connection pipe 13 (14). Since it is prevented from being supplied and diffused throughout the outer pipe 19, a gas accumulation effect is obtained also in the outer pipe 19, and the gas pressure in the outer pipe 19 is further equalized. Will be.

  In the manifold structures according to the first and second embodiments described above, the gas introduction holes 24 and 29 drilled in the gas dispersion plate 23 of FIG. 1 and the rectifying pipe 28 of FIG. It is of course possible to make the hole diameter smaller as it goes downstream. By doing so, the gas pressure in the space between the gas introduction hole 24 (29) and the gas supply hole 25 (30) becomes more equalized and is supplied to each separator 8 through the gas supply holes 25 and 30. It is possible to further equalize the gas supply amount.

  In addition, the gas can be introduced into each manifold 15 (16) at any position such as the central portion, one end portion, or both ends of the tube body. Compared to the introduction, gas rectification can be performed well, which is preferable. In addition, if the gas rectifying effect is good, there is also an advantage that the processing accuracy of the gas introduction holes 24 and 29 can be roughened.

  Next, a third embodiment of the present invention in which the above-described first embodiment is applied to an internal manifold type fuel cell stack 1 will be described with reference to FIG.

  As shown in FIG. 5, a pair of frame-shaped portions 31, 31 project outward from the outer peripheral portion of the separator 8 so as to face each other. Each of the frame-like portions 31 and 31 has a rectangular shape, and a partition 32 provided with a longitudinal slit 33 (gas introduction hole 33) is provided at the center of each frame. Is divided into a gas introduction space 36 into which external gas is introduced and a gas distribution space 37 that supplies the introduced gas to the gas passage 11 (12) of the separator 8.

  The gas distribution space 37 in the frame communicates with the fuel gas passage 11 (or the oxidant gas passage 12) on the outer peripheral surface of the separator 8 through the gas supply hole 34 provided in the frame-like portion 31. In this case, it is preferable to shift the positions of the gas introduction hole 33 and the gas supply hole 34 of the frame-shaped part 31 in the circumferential direction of the separator 8.

  By laminating a large number of separators 8 having such a structure with the power generation cell 5 interposed therebetween, the fuel cell stack 1 including the internal manifolds 15 and 16 formed of the square columnar single tubes 40 on the peripheral side portion can be configured. In the single tube 40, a gas introduction space 36 and a gas distribution space 37 communicating with each other in the stacking direction of the power generation cell 5 and the separator 8 are formed by the partitions 32 of the stacked frame-like portions 31. Note that an insulating frame-shaped gasket 35 is interposed between the adjacent upper and lower frame-shaped portions 31 at the time of lamination.

  In the manifolds 15 and 16 having the above-described configuration, the gas introduction space 36 functions as a gas accumulation space as in the above-described embodiment, and the gas accumulated in the gas introduction space 36 is transmitted from the gas introduction hole 33 of the partition 32. The gas distribution space 37 is introduced with a substantially uniform gas pressure. As a result, the amount of gas supplied to the gas passage 11 (12) of each separator 8 through the gas supply hole 34 can be equalized. As a result, the nonuniformity of the characteristics of each power generation cell 5 is reduced, and the fuel cell The power generation characteristics can be improved.

  Further, by shifting the opposing positions of the gas introduction hole 33 and the gas supply hole 34 of the frame-shaped part 31, the gas from the gas introduction hole 33 is prevented from reaching the gas supply hole 34 directly, and also in the gas distribution space 37. The same gas accumulation effect as that of the gas introduction space 36 can be obtained, and the gas introduced through the gas introduction hole 33 can be evenly diffused into the gas distribution space 37. Thereby, the gas supply amount supplied to each separator 8 through each gas supply hole 34 can be further equalized, and the nonuniformity of the characteristics of each power generation cell 5 can be reduced.

  Next, FIG. 6 shows a configuration of a fourth embodiment in which the above-described second embodiment is applied to an internal manifold.

In this configuration, a large number of separators 8 each having a rectangular frame-shaped portion 31 arranged opposite to each other on the outer peripheral portion are stacked with a power generation cell 5 and an insulating frame-shaped gasket 35 sandwiched therebetween, thereby A rectangular columnar outer tube 41 communicating in the stacking direction is formed, and an inner tube 38 (rectifier tube 38) having a large number of gas introduction holes 39 formed in the peripheral wall in the longitudinal direction of the center of the outer tube 41. This is a double structure in which is provided.
As shown in FIG. 7, the gas introduction holes 39 of the rectifying pipe 38 are drilled at intervals of 90 degrees at three locations in the circumferential direction of the rectifying pipe 38 excluding the separator 8 side, It is continuously drilled in the longitudinal direction at intervals. Although not shown, the gas supply pipe 20 is connected to the upper end portion of the rectifying pipe 38.

  In this configuration, the internal space of the rectifying pipe 38 into which the external gas is introduced functions as a gas accumulation space, and the introduced gas is externally discharged with a uniform gas pressure from the gas introduction hole 39 of the rectifying pipe 38. It comes to be introduced into the tube 41 side. As a result, the amount of gas supplied from the gas supply hole 34 to each gas passage 11, 12 of each separator 8 can be equalized, and the nonuniformity of the characteristics of each power generation cell 5 can be reduced to generate power from the fuel cell. The characteristics can be improved.

  Further, the gas introduced into the manifolds 15 and 16 is jetted in three directions excluding the separator 8 side from the peripheral wall of the rectifying pipe 38, so that the jet gas from the gas introduction hole 39 is directly supplied to the gas supply hole 34. Since this is prevented and the gas is evenly diffused in the outer tube 41, a gas accumulation effect is obtained also in the outer tube 41, and the gas pressure in the outer tube 41 is further equalized. It will be.

In the third and fourth embodiments described above, the gas introduction hole 33 of the partition 32 and the gas introduction hole 39 of the rectifying pipe 38 are all the same diameter, but the hole diameter decreases as the gas flow proceeds downstream. If formed, it is preferable because the gas pressure in the gas distribution space is equalized well.
In addition, gas can be introduced into each manifold 15 (16) at an arbitrary position such as the central portion, one end portion, or both end portions of the tube body. Compared with the case of the part, the gas rectifying effect is good, which is preferable.

  As described above, in the first to fourth embodiments described above, the pipe bodies (single pipes 18 and 40 and outer pipes 19 and 41) constituting the manifold 15 (16) are formed in a quadrangular prism shape, but the shape is not limited to this. Of course, a cylindrical shape may be used.

The perspective view which shows 1st Embodiment of the manifold of this invention. (A) is the longitudinal fragmentary sectional view of FIG. 1, (b) is the cross-sectional view of FIG. The perspective view which shows 2nd Embodiment of the manifold of this invention. FIG. 4 is a cross-sectional view of FIG. 3. The disassembled perspective view of the fuel cell stack which shows 3rd Embodiment of the manifold of this invention. The disassembled perspective view of the fuel cell stack which shows 3rd Embodiment of the manifold of this invention. FIG. 7 is a cross-sectional view of the main part of FIG. 6. The exploded sectional view showing the important section of the solid oxide fuel cell to which the present invention was applied. The exploded perspective view of the principal part same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell stack 5 Power generation cell 8 Separator 11, 12 Gas passage (fuel gas passage, oxidant gas passage)
15, 16 Manifold (manifold for fuel, manifold for oxidizer)
18, 40 Single pipe 19, 41 Outer pipe 21 Nozzle 21b Circumferential wall 22 Injection hole 23 Gas dispersion plate 24, 39 Gas introduction hole 25, 30, 34 Gas supply hole 26, 36 Gas introduction space 27, 37 Inside gas distribution space 28, 38 Tube (rectifier tube)

Claims (6)

A fuel cell stack comprising a plurality of power generation cells and separators alternately stacked, and a flat plate type fuel cell comprising a gas manifold provided in the stacking direction of the power generation cells and separators to distribute reaction gas to each separator In
The manifold has a single-tube structure with gas supply holes in the peripheral wall, and a gas distribution plate having a number of gas introduction holes formed in the longitudinal direction of the pipe is provided to introduce gas into the pipe. And a gas distribution space in which the introduced gas is distributed through the gas supply holes. A gas introduction nozzle is disposed in the gas introduction space so that a tip portion thereof faces the gas dispersion plate, and a plurality of injection holes are formed on at least a peripheral wall of the nozzle. Item 2. A flat plate type fuel cell according to Item 1. A fuel cell stack configured by alternately stacking a plurality of power generation cells and separators, and a plate stack type fuel provided with a gas manifold provided in the stacking direction of the power generation cells and separators to distribute reaction gas to each separator In batteries,
The manifold has a double structure including an outer tube having a gas supply hole in a peripheral wall and an inner tube that is disposed in the outer tube and serves as a gas introduction space, and the inner tube. A flat laminated fuel cell characterized in that a large number of gas introduction holes are formed in the peripheral wall. The position of the said gas introduction hole and the position of the said gas supply hole have a shift | offset | difference in the lamination direction and / or the direction perpendicular | vertical to a lamination direction. Flat plate type fuel cell. The number of the gas introduction holes is two or more, the cross-sectional areas of the gas introduction holes are equal to each other, the gas introduction holes are arranged at equal intervals in the longitudinal direction, and the gas flow velocity flowing through each gas introduction hole is The flat plate type fuel cell according to any one of claims 1 to 4, wherein a flow velocity of the gas flowing through the gas introduction space is larger than that of the gas. 5. The flat plate stacked fuel cell according to claim 1, wherein a cross-sectional area of the gas introduction hole is formed to increase as the gas flows downstream.

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