JP5136471B2 - Fuel cell - Google Patents

Description

  The present invention relates to prevention of heat dissipation of a fuel cell, and more particularly to a structure that suppresses heat dissipation of a cell stack.

  A fuel cell generates electric power and heat simultaneously by electrochemically reacting a fuel gas containing hydrogen and an oxidant gas such as air containing oxygen. Therefore, fuel cells can be classified into various types according to the fuel used and the constituent materials. One of them is a polymer electrolyte fuel cell using a polymer electrolyte membrane.

  FIG. 7 is an enlarged cross-sectional view of an end portion of a conventional general polymer electrolyte fuel cell 51. As shown in FIG. 7, a polymer electrolyte fuel cell 51 includes a cell stack 53 formed by stacking a plurality of unit cells 52 each including a polymer electrolyte membrane, and arranged at both ends of the cell stack 53. A current collecting plate 54 provided, and an end plate 55 disposed further outward are provided. These are fixed by tightening from both sides with bolts (not shown). Further, as shown in FIG. 7, the reaction gas for supplying and discharging the reaction gas (fuel gas and oxidant gas) necessary for power generation and the cooling fluid for cooling the cell stack is provided on the end face of the fuel cell 51. A supply port 56, a cooling fluid supply port, a reactive gas discharge port, and a cooling fluid discharge port are provided. Each supply port and discharge port are connected to an external pipe P.

  In the fuel cell cogeneration system using the polymer electrolyte type fuel cell 51, it is also important to collect heat generated by a chemical reaction together with electric power generated by the fuel cell and supply it as thermal energy. Therefore, it is desirable to insulate the fuel cell stack and recover all the heat generated inside through the reaction gas and the cooling fluid.

  However, in reality, heat is generated due to a temperature difference from the outside air, and thus there is a problem that the amount of exhaust heat recovery is reduced. In order to solve this problem, first, the surface temperature of each part of the fuel cell was measured to estimate the heat dissipation amount. As a result, the heat radiation from the end plate having a large surface area and heat capacity was particularly large. It has been found that this heat is transferred by contact between an external pipe such as a reaction gas pipe joint or a cooling fluid pipe joint through which a high-temperature fluid flows and an end plate.

  Therefore, in order to prevent contact between the end plate and the external pipe, a fuel cell in which a space is provided between the end plate and the external pipe has been proposed (for example, see FIG. 3 of Patent Document 1).

  Hereinafter, the fuel cell disclosed in Patent Document 1 will be described with reference to FIG. FIG. 8A is an enlarged cross-sectional view of an end surface portion of a conventional fuel cell 61, and FIG. 8B is a perspective view of a main part.

  As shown in FIG. 8, the fuel cell 61 includes a pipe joint 63 that connects the cell stack 62 and the external pipe P. The current collector plate 64 and the end plate 65 are provided with through holes 66 and 67 having a diameter larger than that of the pipe joint 63 so that the pipe joint 63 and the end plate 65 do not contact each other.

  According to the above configuration, since there is no contact between the pipe joint 63 and the end plate 65, heat transfer due to contact with the end plate 65 can be prevented, and heat radiation from the end plate can be suppressed.

Further, a method has been proposed in which a heat insulating material is inserted between the end plate and the external pipe and the pipe joint to suppress heat transfer from the external pipe and the pipe joint to the end plate to reduce heat dissipation (for example, a patent). Reference 2).
Japanese Patent Laid-Open No. 7-282836 JP 2007-294330 A

  However, in the fuel cell disclosed in Patent Document 1, heat dissipation due to heat transfer can be reduced in the space between the end plate 65 and the pipe P, but since heat dissipation to the air increases, the outside air temperature and the flow of gas On the contrary, there is a possibility that the heat radiation increases.

  Further, in the fuel cell disclosed in Patent Document 2, since the heat insulating material generally has insufficient rigidity, the heat insulating material may buckle due to a load applied to the piping. As a result, there is a problem that an open space is generated between the end plates and a sufficient heat insulating effect cannot be obtained.

  The present invention solves the above-described problems, and an object thereof is to provide a fuel cell in which heat transfer from a pipe joint to an end plate is suppressed and heat radiation from the end plate is reduced.

  In order to solve the above-described conventional problems, a fuel cell according to the present invention includes a cell stack having a reaction gas flow path and a cooling fluid flow path, a reaction gas flow path or a cooling fluid flow path, and an external piping for reaction gas or A pipe joint interposed between and connected to an external pipe for cooling fluid; and an end plate having a through hole through which the pipe joint is inserted. The pipe joint has two spaces. It has the division structure divided | segmented above and the obstruction | occlusion structure which obstruct | occludes space substantially.

  Thereby, since the contact area of a piping joint and an end plate can be reduced, the heat transfer to an end plate can be suppressed to the minimum. Moreover, since a substantially closed space can be formed between the pipe joint and the through hole, heat transfer from the pipe joint to the outside air can also be suppressed.

  According to the fuel cell of the present invention, it is possible to suppress heat radiation from the end plate due to heat transfer from the piping member and increase the amount of exhaust heat recovery.

  1st invention interposes between a cell stack which has a reactive gas flow path and a cooling fluid flow path, a reactive gas flow path or a cooling fluid flow path, and an external piping for reactive gas or an external piping for cooling fluid A pipe joint, and an end plate having a through hole through which the pipe joint is inserted. The pipe joint substantially divides the space into two or more and the space. Has a closing structure for closing.

  Thereby, since the contact area of a piping joint and an end plate can be reduced, the heat transfer to an end plate can be suppressed to the minimum. Moreover, since a substantially closed space can be formed between the pipe joint and the through hole, heat transfer from the pipe joint to the outside air can also be suppressed.

  2nd invention is a cover part with which the closure structure of a pipe joint is arrange | positioned in the radial direction of the outer periphery of a pipe joint in 1st invention. Thereby, it becomes possible to suppress the convection of the air around a pipe joint, and to insulate more effectively. As a result, it is possible to realize a fuel cell that minimizes heat radiation from the pipe joint and improves the heat recovery amount.

  3rd invention is a rib part in which the division structure of a pipe joint is arranged in the diameter direction of the perimeter of a pipe joint in the 1st invention. Thereby, it becomes possible to effectively suppress the convection of air related to the temperature gradient in the axial direction of the pipe joint.

  4th invention is a rib part by which the division structure of a pipe joint is arrange | positioned in the axial direction of the outer periphery of a pipe joint in 1st invention. Thereby, when arrange | positioning so that a piping joint may become horizontal, it becomes possible to suppress effectively the convection of the air around the piping joint which arises by gravity.

  According to a fifth invention, in any one of the first to fourth inventions, the pipe joint is inserted and fitted into the end plate from the cell stack side. Thereby, since it is not necessary to fix a piping joint and an end plate from the exterior, it is possible to minimize the contact area of a piping joint and an end plate, and to suppress a heat radiation amount more effectively.

  A sixth invention has a current collector plate for taking out the electric power generated in the cell stack between the end plate and the cell stack in any one of the first to fifth inventions, and the pipe joint is a current collector It is arranged at a position that does not overlap the plate, and is sandwiched between the end plate and the cell stack. This makes it possible to prevent corrosion of the current collector plate.

  In a seventh aspect based on the second aspect, a seal member is provided between the outer periphery of the lid and the end plate, and the space is sealed by the seal member. As a result, the space around the pipe joint can be hermetically sealed and heat radiation to the outside air can be reliably prevented.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same reference numerals are given to the same configurations as those of the conventional technology described above, and detailed descriptions thereof will be omitted. The present invention is not limited to the embodiments.

(Embodiment 1)
Hereinafter, the fuel cell according to Embodiment 1 of the present invention will be described in detail.

  First, an outline of the fuel cell 1 according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 3.

  FIG. 1 is a perspective view of a fuel cell 1 according to Embodiment 1 of the present invention. FIG. 2 is an exploded perspective view of unit cell 10 according to Embodiment 1 of the present invention. 3A is an exploded perspective view of the main part of the fuel cell 1 according to Embodiment 1 of the present invention, and FIG. 3B is a perspective view of a pipe joint used in the fuel cell 1 according to Embodiment 1 of the present invention. FIG.

  As shown in FIG. 1, the fuel cell 1 is configured by stacking a cell stack 2, a current collector plate 3, an end plate 4, and pipe joints 5 to 8 and sandwiching them with bolts 22. At this time, the cell stack 2 is generally formed by stacking the unit cells 10 in about 2 to 200 stages according to the required output.

As shown in FIG. 2, the unit cell 10 includes an MEA (electrode electrolyte membrane assembly) 11, a gas seal 12, and a separator 13. The MEA 11 is formed by providing the catalyst layer 15 on both sides of the polymer electrolyte membrane 14 and overlapping the gas diffusion layer 16 on the outside thereof. At this time, the polymer electrolyte membrane 14 is composed of a cation exchange resin that selectively transports hydrogen ions, and the catalyst layer 15 is composed mainly of carbon powder supporting a metal having a catalytic function such as platinum. Has been. Further, the gas diffusion layer 16 has a function of having both the breathability of the reaction gas (fuel gas and oxidant gas) and the conductivity of electrons. Hereinafter, the catalyst layer 15 and the gas diffusion layer 16 may be collectively referred to as electrodes.

  Moreover, the gas seal 12 of the unit cell 10 has, for example, an annular shape, and is disposed on both outer surfaces of the MEA 11 so as to surround the electrodes composed of the catalyst layer 15 and the gas diffusion layer 16. The gas seal 12 prevents fuel gas and oxidant gas from leaking out or mixing different gases.

  Furthermore, the separator 13 of the unit cell 10 is disposed outside the gas seal 12, and a flow path is formed on both surfaces thereof. The flow path formed on the inner surface (gas seal side) of the separator 13 is a reaction gas flow path 13a for supplying a reaction gas (fuel gas or oxidant gas) to the catalyst layer 15, and the flow path formed on the outer surface is A cooling water flow path (not shown) that is a cooling fluid flow path for flowing cooling water between the cells 10. At this time, the heat generated in the MEA 11 can be used as thermal energy by recovering with cooling water. Further, the separator 13 has conductivity and electrically connects adjacent MEAs 11 to each other in series.

  The reaction gas channel 13a and the cooling water channel formed in the separator 13 have an upstream end connected to the supply manifold hole and a downstream end connected to the discharge manifold hole. Further, manifold holes are provided in the peripheral edge portion of the MEA 11 so as to correspond to the manifold holes of the separator 13. Therefore, when the cell stack 2 is assembled by stacking the unit cells 10 including the separator 13 and the MEA 11, the manifold holes of the separator 13 and the MEA 11 are connected to each other and communicate with each other. Thereby, a manifold (flow path) of a fluid such as a reaction gas or cooling water is formed.

  As described above, in the cell stack 2 of the present embodiment, two reaction gas supply manifolds, two reaction gas discharge manifolds, one cooling water supply manifold, and one cooling water discharge manifold are formed in the stacking direction. . One end of the two reaction gas supply manifolds constitutes two reaction gas supply ports, and the two reaction gas discharge manifolds constitute two reaction gas discharge ports. One end of the cooling water supply manifold constitutes a cooling fluid supply port, and one end of the cooling water discharge manifold constitutes a cooling fluid discharge port.

  Further, as described above, a plurality of reaction gas passages and cooling water passages are formed in the separator 13 of each unit cell 10. Therefore, the reaction gas channel and the cooling water channel require a supply port for supplying the reaction gas (fuel gas and oxidant gas) and cooling water and an exhaust port for discharging the reaction gas.

  Therefore, the arrangement relationship between the supply port and the discharge port of the reaction gas and the cooling water provided in the end plate, the connection joint, and the cell stack will be described below with reference to FIG. Note that FIG. 3A shows only the configuration of the end plate 4 and the cell stack 2 on the side connected to the external piping for easy understanding.

  As shown in FIG. 3A, two reaction gas supply ports 17 for supplying a reaction gas are provided on one end surface of the end surface of the cell stack 2 (the outer surface of the separator 13 in the outermost unit cell). Two reaction gas outlets 18 for discharging the reaction gas are formed. Furthermore, a cooling fluid supply port 20 for supplying cooling water and a cooling fluid discharge port 19 for discharging cooling water are formed. And the reaction gas and cooling water which entered from the reaction gas supply port 17 and the cooling fluid supply port 20 flow through the inside or the boundary of each unit cell 10, and from the reaction gas discharge port 18 and the cooling fluid discharge port 19. Discharged.

Further, between the cell stack 2 and the end plate 4, current collecting plates 3 for obtaining good electrical contact between the cell stack 2 and an external circuit (not shown) are provided on both outer sides of the cell stack 2 ( In FIG. 3A, only one is shown. At this time, the current collector plate 3 is usually provided with
The reaction gas supply port 17, the cooling fluid supply port 20, the reaction gas discharge port 18, and the cooling fluid discharge port 19 are provided so as to fit within the separator 13.

  Further, the end plate 4 is connected to the current collecting plate 3 in order to sandwich and fix the cell stack 2 and the current collecting plate 3 from both sides via bolts 22 (not shown in the drawing). Furthermore, it is arranged outward. Note that the end plate 4 is made of, for example, an insulating resin. At this time, the bolt 22 has at least the length of the cell stack of the fuel cell 1. Specifically, the bolt 22 is passed through a bolt through-hole 9 formed in one end plate 4, current collector plate 3 and cell stack 2 and the other end plate (not shown), and a nut (not shown). The whole fuel cell 1 is fixed by fastening at. Accordingly, the end plate 4 is required to have high rigidity and a certain thickness in order to firmly and uniformly hold the entire fuel cell 1 from both sides.

  Further, the end plate 4 on the side connected to the external pipe is located at a position corresponding to the reaction gas supply port 17, the cooling fluid supply port 20, the reaction gas discharge port 18, and the cooling fluid discharge port 19 provided in the cell stack 2. For example, a circular through hole 23 is provided.

  Then, by inserting the pipe joints 5 to 8 into the through hole 23 from the current collector 3 side, the reaction gas supply port 17 and the cooling fluid provided in the external pipe and the cell stack 2 through the pipe joints 5 to 8 are provided. The supply port 20, the reaction gas discharge port 18 and the cooling fluid discharge port 19 are connected.

  In the above description, the end plate 4 is described as an example of a single member made of resin, but is not limited thereto. For example, it may be composed of an insulating plate (insulating plate) disposed on the current collector plate 3 side and a strength retaining plate (so-called end plate) made of, for example, metal, disposed on the outside thereof, These may be integrated to form a laminated structure such as a two-layer structure.

  Moreover, as shown to Fig.3 (a), the piping joint 5 is mainly comprised from the cell stack connection part 5a, the external piping connection part 5b, and the cylindrical part 5c. In the following, the pipe joint 5 will be described as an example, but the configuration of the pipe joints 6, 7, and 8 is the same as that of the pipe joint 5. And the cell stack connection part 5a of the pipe joint 5 is formed in the base end part of the pipe joint 5, and it passes through the reaction gas supply port 17 and the seal part 30 which were formed in the cell stack 2 shown to Fig.3 (a). Connected. Furthermore, the external pipe connection portion 5b is formed at the tip portion of the pipe joint 5 and is connected to the external pipe described below. And the cylindrical part 5c is formed in the center part between the cell stack connection part 5a and the external piping connection part 5b, and becomes a flow path of the reactive gas. At this time, the pipe joint is preferably formed of a resin having a low thermal conductivity. Thereby, the heat conduction to the outside can be suppressed low, and the influence of heat radiation can be reduced more effectively.

  In the above description, the pipe joints 5 to 8 have been described as examples having the same configuration, but the present invention is not limited thereto. For example, you may perform deformation | transformation, such as enlarging an internal diameter, according to the property and flow volume of the fluid which pass the piping joints 5-8, respectively.

  Moreover, as shown in FIG.3 (b), the cover part 5d formed cyclically | annularly in the circumferential direction of the cylindrical part 5c is provided in the outer periphery of the cylindrical part 5c of the pipe joint 5, and the cylindrical part 5c One or more rib portions 5e are provided in a direction parallel to the axial direction. And the division | segmentation structure which divides | segments the space of the through-hole 23 of the end plate 4 in which the pipe joint 5 is inserted, and the obstruction | occlusion structure which obstruct | occlude are implement | achieved by the cover part 5d and the rib part 5e.

Thereby, the convection of the air layer around the pipe joint 5 can be suppressed, and the heat insulation can be improved. Further, by minimizing the contact area between the pipe joint 5 and the end plate 4, heat radiation due to heat conduction to the end plate 4 can be reduced.

  In addition, in this Embodiment, although the cover part 5d and the rib part 5e showed the example integrally molded with the pipe joint 5 with the same member as the pipe joint 5, it is not restricted to this. For example, the lid portion 5d and the rib portion 5e may be formed of a material having low thermal conductivity such as resin or wood and integrated with the pipe joint 5 by post-processing. Thereby, the heat radiation by heat conduction can be further reduced.

  In the present embodiment, the example in which all the pipe joints are provided with the lid parts 5d and the rib parts 5e has been described. However, the present invention is not limited to this, and only the pipe joints for the supply port and the discharge port for the cooling fluid such as cooling water. You may provide the cover part 5d and the rib part 5e. Thereby, the structure of the other pipe joint can be simplified.

  Below, the connection structure which connects external piping and the supply port and discharge port of reaction gas and cooling water which are the points of this invention through a piping joint is demonstrated using FIG.

  FIG. 4A is a schematic diagram for explaining the connection between the external pipe and the cooling fluid discharge port via the pipe joint in the fuel cell according to Embodiment 1 of the present invention. FIG. FIG. 4C is a partial perspective view, and FIG. 4C is a perspective view showing an installation state of the pipe joint. Here, the vicinity of the pipe joint 7 connected to the cooling fluid discharge port 19 will be described as an example, but the same applies to the vicinity of other pipe joints.

  As shown in FIG. 4 (a), the cell stack connection portion 7a located at the base end portion of the pipe joint 7 is a seal formed on the end surface of the cell stack 2 (the outer surface of the separator in the single cell 10 located at the extreme end). The cell stack 2 is contacted through an O-ring 32 loaded in the groove 31. The end plate 4 holds the cell stack connection portion 7a to seal the fluid flowing through the cooling fluid discharge port 19 from leaking to the outside.

  Further, the external pipe connection portion 7 b located at the tip end portion of the pipe joint 7 protrudes further outward than the end face of the end plate 4 and can be connected to the external pipe P. In the present embodiment, the configuration in which the external pipe connection portion 7b and the external pipe P can be connected with one touch is shown as an example, but other connection mechanisms may be employed. For example, the external pipe connection portion 7b may be connected to the external pipe P with a screw.

  Further, the tubular portion 7 c located at the center portion (center portion) of the pipe joint 7 has a majority portion in the longitudinal direction located in the through hole 23 of the end plate 4. Here, on the outer periphery of the tubular portion 7c of the pipe joint 7, a lid portion 7d surrounding the tubular portion 7c in an annular shape in the circumferential direction is formed. A plurality of rib portions 7e are formed in a direction parallel to the axial direction of the cylindrical portion 7c. At this time, the outer shape of the lid portion 7 d and the rib portion 7 e is formed to be slightly smaller than the inner shape of the through hole 23 of the end plate 4. When the pipe joint 7 is inserted into the space in the through hole 23, the space of the through hole 23 is closed and sealed with the lid portion 7 d and the inner wall of the through hole 23 of the end plate 4 and the gap 24. At the same time, it is divided by the rib portion 7e.

  Thereby, the convection to the exterior of the air layer around the piping joint 7 can be suppressed, and heat insulation can be improved.

According to the present embodiment, the space between the pipe joint 7 and the through hole 23 of the end plate 4 is closed to form a substantially closed space, thereby providing a heat insulation space by still air around the pipe joint 7. be able to. Thereby, even if it uses in a cold district, for example, the heat radiation by the convection to the outside air via the piping joint 7 can be suppressed significantly. In addition, since the pipe joint 7 and the end plate 4 are in contact with each other only by the rib portion 7e and the lid portion 7d, heat dissipation due to heat transfer to the end plate 4 can be significantly suppressed by reducing the contact area.
Further, as shown in FIG. 4C, for example, when the pipe joint 7 is installed in the horizontal direction, air convection caused by gravity generated in the space divided by the rib portion 7e of the pipe joint 7 is suppressed. it can. Here, convection of air due to gravity means that heated air rises and cooled air falls, and so on.

  Moreover, according to this Embodiment, the rigidity of the pipe joint 7 improves by providing the cover part 7d and the rib part 7e in the pipe joint 7. FIG. Furthermore, since the lid portion 7d and the rib portion 7e of the pipe joint 7 can be disposed between the end plates 4 with a slight gap 24, the pipe joint 7 can be supported in the through hole 23 with almost no inclination. As a result, it is possible to prevent damage due to deformation (tilt) of the pipe joint 7 due to an external load when the pipe joint 7 and the external pipe P are connected.

(Embodiment 2)
Hereinafter, a fuel cell according to Embodiment 2 of the present invention will be described with reference to FIG.

  FIG. 5A is a schematic diagram for explaining the connection between the external pipe and the cooling fluid discharge port via the pipe joint in the fuel cell according to Embodiment 2 of the present invention, and FIG. FIG. 5C is a partial perspective view, and FIG. Note that the configuration of the fuel cell other than the vicinity of the pipe joint is the same as that of the first embodiment, and thus the description thereof is omitted. Note that, here, the periphery of the pipe joint 7 connected to the cooling fluid discharge port 19 will be described as an example, but the periphery of the other pipe joints 5, 6, 8 is the same.

  That is, as shown in FIG. 5, the fuel cell according to the present embodiment is different from the first embodiment in that a rib portion 7 f surrounding the tubular portion 7 c is further provided on the outer peripheral portion of the pipe joint 7. Different.

  Specifically, as shown in FIGS. 5A and 5C, a rib portion 7f is formed on the outer periphery of the tubular portion 7c between the cell stack connection portion 7a and the lid portion 7d of the pipe joint 7. The pipe joint 7 is configured.

  Thereby, as shown in FIG.5 (c), when the pipe joint 7 is installed in the perpendicular direction, the air resulting from the gravity which arises in the space divided | segmented by the rib part 7e and the rib part 7f of the pipe joint 7 is shown. , And heat dissipation due to convection to the outside air via the pipe joint 7 can be suppressed. That is, since the space of the through hole 23 can be divided into smaller spaces than the rib portion 7e and the rib portion 7f of the pipe joint 7, it is possible to further enhance the air static effect and greatly improve the heat insulation effect. As a result, a fuel cell with high exhaust heat recovery efficiency can be realized.

  In this embodiment, an example in which one rib portion 7f is provided has been described. However, the present invention is not limited to this, and a plurality of rib portions 7f may be provided in accordance with the nature and flow rate of the fluid passing therethrough. Thereby, the optimal heat insulation effect can be acquired.

(Embodiment 3)
Hereinafter, the fuel cell according to Embodiment 3 of the present invention will be described with reference to FIG.

  FIG. 6A is a schematic diagram for explaining the connection between the external pipe and the cooling fluid discharge port via the pipe joint in the fuel cell according to Embodiment 3 of the present invention. FIG. It is a fragmentary perspective view. Note that the configuration of the fuel cell other than the vicinity of the pipe joint is the same as that of the first embodiment, and thus the description thereof is omitted. Note that, here, the periphery of the pipe joint 7 connected to the cooling fluid discharge port 19 will be described as an example, but the periphery of the other pipe joints 5, 6, 8 is the same.

  That is, as shown in FIG. 6, the fuel cell according to the present embodiment is different from the first embodiment in that the seal member 33 is provided around the lid portion 7 d of the pipe joint 7.

  Specifically, as shown in FIG. 6A, a seal member 33 made of, for example, an O-ring made of fluoro rubber is provided on the outer peripheral side surface of the lid portion 7d of the pipe joint 7, and the inner wall of the through hole 23 of the end plate 4 It is made to adhere to and constitutes a sealed structure.

  Thereby, the space around the pipe joint 7 can be completely blocked from the outside air by the sealing effect of the seal member 33. As a result, it is possible to realize a fuel cell in which the heat insulation effect is further improved and the heat recovery efficiency is remarkably improved.

  In the above description, fluorine rubber has been described as an example of the seal member 33, but the seal member 33 is not limited thereto. For example, a general seal member such as EPDM or silicon rubber may be used as the O-ring shape. Alternatively, a liquid rubber material, an olefin-based elastomer, or the like may be directly molded and provided integrally on the outer periphery of the lid portion 7d of the pipe joint 7. Furthermore, after inserting the pipe joint 7 into the through hole 23 of the end plate 4, the seal member 33 may be configured by filling the gap between the lid portion 7 d and the through hole 23 with a liquid rubber material or a silicon sealant material.

  Moreover, although the example which provided the sealing member in the piping joint of Embodiment 1 demonstrated above, it is not restricted to this, Even if it provides in the piping joint of Embodiment 2, the same effect is acquired.

  In the first embodiment, an example is a divided structure in which the rib portion 7e is divided into four in the radial direction of the wiring joint. In the second embodiment, the divided structure is further divided into two in the longitudinal direction of the pipe joint. However, the present invention is not limited to this. For example, the pipe joint may be divided into two or more in the radial direction and three or more in the longitudinal direction.

  The fuel cell of the present invention is useful in technical fields such as a fuel cell that can suppress heat dissipation from a pipe joint and improve heat recovery efficiency.

1 is a perspective view of a fuel cell according to Embodiment 1 of the present invention. 1 is an exploded perspective view of a unit cell according to Embodiment 1 of the present invention. (A) An exploded perspective view of the main part of the fuel cell according to Embodiment 1 of the present invention (b) A perspective view of a pipe joint used in the fuel cell according to Embodiment 1 of the present invention (A) Schematic diagram for explaining connection between external pipe and cooling fluid discharge port via pipe joint in fuel cell of Embodiment 1 of the present invention (b) Partial perspective view around pipe joint (c) Pipe joint The perspective view which shows the installation state of (A) Schematic diagram for explaining connection between external pipe and cooling fluid discharge port via pipe joint in fuel cell of embodiment 2 of the present invention (b) Partial perspective view around pipe joint (c) Pipe joint The perspective view which shows the installation state of (A) Schematic diagram illustrating connection between external pipe and cooling fluid discharge port via pipe joint in fuel cell of Embodiment 3 of the present invention (b) Partial perspective view of the periphery of the pipe joint Sectional view enlarging the end of a conventional general polymer electrolyte fuel cell (A) Sectional view in which an end face portion of a conventional fuel cell is enlarged (b) Perspective view

1, 51, 61 Fuel cell 2, 53, 62 Cell stack 3, 54, 64 Current collecting plate 4, 55, 65 End plate 5, 6, 7, 8, 63 Pipe joint 5a, 7a Cell stack connection 5b, 7b External piping connection portion 5c, 7c Tubular portion 5d, 7d Lid portion 5e, 7e, 7f Rib portion 9 Bolt through hole 10, 52 Single cell 11 MEA (electrode electrolyte membrane assembly)
DESCRIPTION OF SYMBOLS 12 Gas seal 13 Separator 13a Reaction gas flow path 14 Polymer electrolyte membrane 15 Catalyst layer 16 Gas diffusion layer 17,56 Reaction gas supply port 18 Reaction gas discharge port 19 Cooling fluid discharge port 20 Cooling fluid supply port 22 Bolt 23,66, 67 Through-hole 24 Gap 30 Seal part 31 Seal groove 32 O-ring 33 Seal member P External piping

Claims (7)

A cell stack having a reaction gas flow path and a cooling fluid flow path;
A pipe joint interposed between and connected between the reaction gas flow path or the cooling fluid flow path and the reaction gas external pipe or the cooling fluid external pipe;
An end plate having a through hole through which the pipe joint is inserted and having a space;
The pipe joint has a divided structure that divides the space into two or more and a closed structure that substantially closes the space. 2. The fuel cell according to claim 1, wherein the closing structure of the pipe joint is a lid portion arranged in a radial direction of an outer periphery of the pipe joint. 2. The fuel cell according to claim 1, wherein the divided structure of the pipe joint is a rib portion arranged in a radial direction of an outer periphery of the pipe joint. 2. The fuel cell according to claim 1, wherein the divided structure of the pipe joint is a rib portion arranged in an axial direction of an outer periphery of the pipe joint. The fuel cell according to any one of claims 1 to 4, wherein the pipe joint is inserted and fitted into the end plate from the cell stack side. A current collecting plate for taking out the electric power generated in the cell stack between the end plate and the cell stack; and the pipe joint is disposed at a position not overlapping the current collecting plate; The fuel cell according to claim 1, wherein the fuel cell is sandwiched between the cell stacks. The fuel cell according to claim 2, wherein a seal member is provided between an outer periphery of the lid portion and the end plate, and the space is sealed by the seal member.