JP2014157776A - Fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to suppress pressure loss in a piping pipe as much as possible and to circulate fluid smoothly.SOLUTION: A fuel cell stack 10 includes: a plurality of fuel cells 12 that are stacked; and a first end plate 18a and a second end plate 18b disposed at both ends in a stacking direction. An oxidant gas-supplying coupling piping pipe 54a is attached thereto while being communicated to an oxidant gas supplying coupling hole 32a. The oxidant gas-supplying coupling piping pipe 54a includes a piping pipe intermediate portion 70 whose opening cross sectional area is set at a value larger than an opening cross sectional area of an oxidant gas inlet 66 and an opening cross sectional area of an oxidant gas outlet 68.

Description

  The present invention relates to a fuel cell stack having a fuel cell in which an electrolyte membrane / electrode structure provided with electrodes on both sides of an electrolyte membrane and a separator are stacked, and a plurality of the fuel cells are stacked.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure in which an anode electrode is disposed on one side of an electrolyte membrane made of a polymer ion exchange membrane and a cathode electrode is disposed on the other surface side ( MEA) is provided with a power generation cell sandwiched between separators. A fuel cell is usually incorporated in a fuel cell vehicle as an in-vehicle fuel cell stack, for example, by stacking a predetermined number of power generation cells.

  In the above fuel cell, a fuel gas channel for flowing fuel gas to the anode electrode and an oxidant gas channel for flowing oxidant gas to the cathode electrode are provided in the plane of the separator. Furthermore, between the separators, a cooling medium flow path for flowing the cooling medium is provided along the surface direction of the separator.

  The end plate disposed at one end in the stacking direction has at least a fuel gas supply passage for supplying fuel gas to the fuel gas passage, a fuel gas discharge passage for discharging spent fuel gas from the fuel gas passage, Fluid communication holes such as an oxidant gas supply communication hole for supplying oxidant gas to the oxidant gas flow path and an oxidant gas discharge communication hole for discharging used oxidant gas from the oxidant gas flow path are formed. ing.

  In this case, the fuel cell is connected to external equipment such as a humidifier that humidifies the oxidant gas or the fuel gas before the fuel cell is supplied to the fuel cell. At that time, the external piping provided in the external equipment is often set in a cylindrical shape, while the fluid communication hole formed in the end plate has a rectangular shape or a triangular shape (non-circular shape). Yes. For this reason, there is a problem that it is difficult to airtightly connect the circular external pipe and the noncircular fluid communication hole.

  Therefore, a fuel cell stack disclosed in Patent Document 1 is known. In this fuel cell stack, one end plate is provided with a resin connection pipe that connects a non-circular communication hole and a circular external pipe. The resin connection pipe includes a non-circular cylindrical part communicating with a non-circular communication hole, a circular cylindrical part communicating with a circular external pipe, and the non-circular cylindrical part along the thickness direction of one end plate. A circular cylindrical portion and a connecting cylindrical portion that communicates the circular cylindrical portion are integrally provided.

JP 2009-224194 A

  By the way, one end of a circular external pipe is connected to the resin-made connecting pipe, and the other end of the circular external pipe is connected to an external device. In this case, particularly when fluid is supplied to the fuel cell stack through the resin connection pipe from the external pipe, pressure loss is likely to occur inside the pipe. For this reason, there exists a problem that the smooth distribution | circulation of the fluid is not performed within piping.

  The present invention solves this type of problem, and an object of the present invention is to provide a fuel cell stack capable of suppressing pressure loss in piping as much as possible and allowing fluid to flow smoothly. And

  The present invention has a fuel cell in which an electrolyte membrane / electrode structure provided with electrodes on both sides of an electrolyte membrane and a separator are stacked, and a plurality of the fuel cells are stacked and end plates are arranged at both ends in the stacking direction. And at least one of the end plates communicates with the fluid communication hole and external piping in the stacking direction of the fuel cell. The present invention relates to a fuel cell stack to which a connecting pipe is connected.

  In this fuel cell stack, the connecting pipe is set such that the opening cross-sectional area of the pipe intermediate portion is larger than the opening cross-sectional area of the fluid inlet and the opening cross-sectional area of the fluid outlet.

  Further, in this fuel cell stack, the inner wall surface of the connection pipe is formed smoothly from the fluid inlet to the pipe intermediate part and from the fluid outlet to the pipe intermediate part, and in the pipe length direction. It is preferable to be configured only by an outward curved surface that curves outward.

  Further, in this fuel cell stack, the connection pipe has two pipe intermediate parts, two fluid outlets and one fluid inlet integrally, and a total intermediate part opening obtained by adding up the opening cross-sectional areas of the two pipe intermediate parts. The cross-sectional area is set to a value larger than the opening cross-sectional area of the fluid inlet, while the total intermediate portion opening cross-sectional area is larger than the total outlet-side opening cross-sectional area obtained by adding the opening cross-sectional areas of the two fluid outlets. It is preferable to set a large value.

  According to the present invention, the pipe intermediate portion of the connection pipe is set to have an opening cross-sectional area larger than the opening cross-sectional area of the fluid inlet and the opening cross-sectional area of the fluid outlet. Accordingly, the pressure loss of the fluid is suppressed as much as possible in the connecting pipe, so that the fluid can be circulated smoothly and reliably. In particular, even when the connecting pipe is bent in the middle, the internal pressure loss does not increase, and a good fluid flow is performed.

It is a schematic perspective explanatory view from the 1st end plate side of the fuel cell stack concerning the embodiment of the present invention. It is a schematic perspective explanatory view from the second end plate side of the fuel cell stack. It is a principal part disassembled perspective explanatory drawing of the fuel cell which comprises the said fuel cell stack. It is a perspective explanatory view showing the inside of oxidant gas supply connection piping which constitutes the fuel cell stack. It is a section explanatory view of the above-mentioned oxidizing gas supply connection piping. It is a perspective explanatory view showing the inside of fuel gas supply connection piping which constitutes the fuel cell stack. It is a section explanatory view of the fuel gas supply connection piping. It is a perspective explanatory view showing the inside of the cooling medium supply connection piping which constitutes the fuel cell stack. It is comparison explanatory drawing of the pressure loss of this embodiment and a comparative example.

  As shown in FIGS. 1 and 2, a fuel cell stack 10 according to an embodiment of the present invention is mounted on, for example, a fuel cell electric vehicle (not shown). In the fuel cell stack 10, a plurality of fuel cells 12 are stacked in the horizontal direction (arrow B direction) with the electrode surface in an upright posture. Note that the fuel cell stack 10 may be configured by stacking a plurality of fuel cells 12 in the direction of gravity.

  At one end in the stacking direction of the fuel cell 12, a first terminal plate 14a, a first insulating plate 16a, and a first end plate 18a are sequentially arranged outward. At the other end of the fuel cell 12 in the stacking direction, a second terminal plate 14b, a second insulating plate 16b, and a second end plate 18b are sequentially disposed outward.

  A first power output terminal 20a connected to the first terminal plate 14a extends outward from the center portion of the horizontally long first end plate 18a (see FIG. 1). A second power output terminal 20b connected to the second terminal plate 14b extends outward from the center portion of the horizontally long second end plate 18b (see FIG. 2).

  Between the sides of the first end plate 18a and the second end plate 18b, both ends of the connecting bar 22 are fixed by screws 24, and a plurality of stacked fuel cells 12 are subjected to a tightening load in the stacking direction (arrow B direction). Give.

  As shown in FIG. 3, the fuel cell 12 includes an electrolyte membrane / electrode structure 26, and a first metal separator 28 and a second metal separator 30 that sandwich the electrolyte membrane / electrode structure 26.

  The first metal separator 28 and the second metal separator 30 are made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a metal plate that has been subjected to anticorrosion surface treatment on its metal surface. The first metal separator 28 and the second metal separator 30 have a rectangular planar shape, and are formed into a concavo-convex shape by pressing a metal thin plate into a wave shape. Instead of the first metal separator 28 and the second metal separator 30, for example, a carbon separator may be used.

  The first metal separator 28 and the second metal separator 30 have a horizontally long shape, the long side extends in the horizontal direction (arrow A direction), and the short side extends in the gravity direction (arrow C direction). Composed. In addition, you may comprise so that a short side may extend in a horizontal direction and a long side may extend in a gravitational direction.

  A rectangular shape (or a triangular shape) such as a rectangular shape that communicates with each other in the arrow B direction and supplies an oxidant gas, for example, an oxygen-containing gas, to one edge of the long side direction (arrow A direction) of the fuel cell 12 The oxidant gas supply communication hole 32a and a fuel gas supply communication hole 34a having a rectangular shape (or a triangular shape) such as a rectangle for supplying a fuel gas, for example, a hydrogen-containing gas, are provided.

  The other end edge in the long side direction of the fuel cell 12 communicates with each other in the direction of arrow B, and has a rectangular (or triangular) fuel gas discharge communication hole 34b such as a rectangle for discharging the fuel gas, and an oxidant. A rectangular (or triangular) oxidant gas discharge communication hole 32b for discharging gas is provided.

  Both ends of the fuel cell 12 in the short side direction (arrow C direction) (one side in the horizontal direction), that is, on the side of the oxidant gas supply communication hole 32a and the fuel gas supply communication hole 34a are in the direction of arrow B. Two cooling medium supply communication holes 36a having a rectangular shape (or a triangular shape) such as a rectangle for supplying the cooling medium are provided vertically on opposite sides.

  The fuel cell 12 communicates with each other in the direction of arrow B on the other side (the other end in the horizontal direction) of both ends in the short side direction, that is, on the fuel gas discharge communication hole 34b and the oxidant gas discharge communication hole 32b side. In addition, two rectangular (or triangular) cooling medium discharge communication holes 36b such as a rectangle for discharging the cooling medium are provided vertically on opposite sides.

  The electrolyte membrane / electrode structure 26 includes, for example, a solid polymer electrolyte membrane 38 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode electrode 40 and an anode electrode 42 sandwiching the solid polymer electrolyte membrane 38. Prepare.

  The cathode electrode 40 and the anode electrode 42 are formed by uniformly applying a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface thereof to the surface of the gas diffusion layer. And an electrode catalyst layer (not shown) to be formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 38.

  An oxidant gas flow path 44 that connects the oxidant gas supply communication hole 32a and the oxidant gas discharge communication hole 32b is formed on the surface 28a of the first metal separator 28 facing the electrolyte membrane / electrode structure 26. The oxidant gas channel 44 is formed by a plurality of wavy channel grooves (or linear channel grooves) extending in the direction of arrow A.

  A fuel gas flow path 46 that connects the fuel gas supply communication hole 34 a and the fuel gas discharge communication hole 34 b is formed on the surface 30 a of the second metal separator 30 facing the electrolyte membrane / electrode structure 26. The fuel gas channel 46 is formed by a plurality of wave-like channel grooves (or linear channel grooves) extending in the direction of arrow A.

  Between the surface 30b of the second metal separator 30 and the surface 28b of the adjacent first metal separator 28, a cooling medium flow path communicating with the cooling medium supply communication holes 36a, 36a and the cooling medium discharge communication holes 36b, 36b. 48 is formed. The cooling medium flow path 48 extends in the horizontal direction and allows the cooling medium to flow over the electrode range of the electrolyte membrane / electrode structure 26.

  A first seal member 50 is integrally formed on the surfaces 28 a and 28 b of the first metal separator 28 around the outer peripheral edge of the first metal separator 28. A second seal member 52 is integrally formed on the surfaces 30 a and 30 b of the second metal separator 30 around the outer peripheral edge of the second metal separator 30.

  As the first seal member 50 and the second seal member 52, for example, EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber or the like, cushion material Alternatively, an elastic seal member such as a packing material is used.

  As shown in FIG. 1, the oxidant gas communicating with the oxidant gas supply communication hole 32a, the oxidant gas discharge communication hole 32b, the fuel gas supply communication hole 34a, and the fuel gas discharge communication hole 34b is connected to the first end plate 18a. A supply connection pipe 54a, an oxidant gas discharge connection pipe 54b, a fuel gas supply connection pipe 56a, and a fuel gas discharge connection pipe 56b are attached.

  The oxidant gas supply connecting pipe 54 a has a plate-like attachment portion 58, and the plate-like attachment portion 58 is disposed corresponding to the oxidant gas supply communication hole 32 a of the first end plate 18 a through the seal 60. . The plate-like attachment portion 58 is fixed to the first end plate 18a by screws 62. A main body portion 64 is integrally formed from the plate-like attachment portion 58, and a circular oxidant gas inlet (fluid inlet) 66 is provided at the tip of the main body portion 64.

  As shown in FIG. 4, a rectangular (or triangular) oxidant gas outlet (fluid outlet) 68 that communicates with the oxidant gas supply communication hole 32 a is formed in the plate-like attachment portion 58. The oxidant gas supply connecting pipe 54 a has a pipe intermediate part 70 located between the oxidant gas inlet 66 and the oxidant gas outlet 68.

  As shown in FIGS. 4 and 5, the opening cross-sectional area W1 of the pipe intermediate portion 70 is set to a value larger than the opening cross-sectional area W2 of the oxidant gas inlet 66 and the opening cross-sectional area W3 of the oxidant gas outlet 68. (W1> W2, W1> W3).

  The inner wall surface 54ai of the oxidant gas supply connecting pipe 54a is formed smoothly from the oxidant gas inlet 66 to the pipe intermediate part 70 and from the oxidant gas outlet 68 to the pipe intermediate part 70, respectively. The inner wall surface 54ai of the oxidant gas supply connecting pipe 54a is constituted by only an outward curved surface that is smoothly continuous as a whole and curved outward in the pipe length direction. That is, the inner wall surface 54ai of the oxidant gas supply connecting pipe 54a is not provided with a portion that is curved or bent (reduced portion) inward.

  The oxidant gas discharge connection pipe 54b is configured in the same manner as the oxidant gas supply connection pipe 54a described above, and the same components are denoted by the same reference numerals and detailed description thereof is omitted. To do. The oxidant gas supply connection pipe 54a and the oxidant gas discharge connection pipe 54b are connected to an external device (not shown) via an external pipe.

  As shown in FIG. 1, the fuel gas supply connecting pipe 56 a has a plate-like attachment portion 72, and the plate-like attachment portion 72 corresponds to the fuel gas supply communication hole 34 a of the first end plate 18 a through a seal 74. Arranged. The plate-like attachment portion 72 is fixed to the first end plate 18 a by screws 76. A main body 78 is integrally formed from the plate-like attachment portion 72, and a circular fuel gas inlet (fluid inlet) 80 is provided at the tip of the main body 78. The main body 78 is curved and formed with an angle of approximately 90 °. That is, the fuel gas flow direction at the fuel gas inlet 80 is set to a direction orthogonal to the fuel gas flow direction of the fuel gas supply communication hole 34a.

  As shown in FIG. 6, a rectangular (or triangular) fuel gas outlet (fluid outlet) 82 communicating with the fuel gas supply communication hole 34 a is formed in the plate-like attachment portion 72. The fuel gas supply connecting pipe 56 a has a pipe intermediate portion 84 located between the fuel gas inlet 80 and the fuel gas outlet 82.

  6 and 7, the opening cross-sectional area W4 of the pipe intermediate portion 84 is set to a value larger than the opening cross-sectional area W5 of the fuel gas inlet 80 and the opening cross-sectional area W6 of the fuel gas outlet 82 (W4). > W5, W4> W6).

  The inner wall surface 56ai of the fuel gas supply connection pipe 56a is formed smoothly from the fuel gas inlet 80 to the pipe intermediate part 84 and from the fuel gas outlet 82 to the pipe intermediate part 84, respectively. The inner wall surface 56ai of the fuel gas supply connecting pipe 56a is constituted only by an outwardly curved surface that is smoothly continuous as a whole and that curves outwardly in the pipe length direction. That is, the inner wall surface 56ai of the fuel gas supply connecting pipe 56a is not provided with a portion that is curved or bent (reduced portion) inward.

  The fuel gas discharge connection pipe 56b is configured in the same manner as the fuel gas supply connection pipe 56a described above, and the same components are denoted by the same reference numerals and detailed description thereof is omitted. The fuel gas supply connection pipe 56a and the fuel gas discharge connection pipe 56b are connected to an external device (not shown) via an external pipe.

  As shown in FIG. 2, the second end plate 18b is integrally formed with a cooling medium supply connecting pipe 86a that communicates integrally with the upper and lower cooling medium supply communication holes 36a and 36a and upper and lower cooling medium discharge communication holes 36b and 36b. A communicating cooling medium discharge connecting pipe 86b is attached.

  The cooling medium supply connecting pipe 86a has a pair of plate-like attachment portions 88, and each plate-like attachment portion 88 is disposed in each cooling medium supply communication hole 36a of the second end plate 18b via a seal 90, respectively. The plate-like attachment portion 88 is fixed to the second end plate 18b by screws 92. A main body portion 94 is integrally formed from each plate-like attachment portion 88, and a curved piping portion 96 is integrally provided at the central portion of the main body portion 94. A circular cooling medium inlet (fluid inlet) 98 is formed at the tip of the pipe portion 96.

  As shown in FIG. 8, each plate-like attachment portion 88 is formed with a rectangular (or triangular) cooling medium outlet (fluid outlet) 100 communicating with the cooling medium supply communication hole 36a. The cooling medium supply connecting pipe 86 a has a pair of pipe intermediate portions 102 located between the cooling medium inlet 98 and each cooling medium outlet 100.

  The total intermediate portion opening cross-sectional area 2 × W7 obtained by summing the opening cross-sectional areas W7 of the respective pipe intermediate portions 102 is the total outlet side where the opening cross-sectional area W8 of the cooling medium inlet 98 and the opening cross-sectional area W9 of each cooling medium outlet 100 are totaled. A value larger than the opening cross-sectional area 2 × W9 is set (2 × W7> W8, 2 × W7> 2 × W9).

  The inner wall surface 86ai of the cooling medium supply connecting pipe 86a is smoothly formed from the cooling medium inlet 98 to the pipe intermediate part 102 and from each cooling medium outlet 100 to the pipe intermediate part 102. The inner wall surface 86ai of the cooling medium supply connecting pipe 86a is constituted only by an outwardly curved surface that is smoothly continuous as a whole and is curved outwardly in the pipe length direction. That is, the inner wall surface 86ai of the cooling medium supply connecting pipe 86a is not provided with a portion that is curved or bent inward.

  The cooling medium discharge connecting pipe 86b is configured in the same manner as the cooling medium supply connecting pipe 86a, and the same reference numerals are given to the same components, and the detailed description thereof will be given. Omitted. The cooling medium supply connecting pipe 86a and the cooling medium discharge connecting pipe 86b are connected to an external device (not shown) via an external pipe.

  The operation of the fuel cell stack 10 configured as described above will be described below.

  First, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied from the oxidant gas supply connection pipe 54a of the first end plate 18a to the oxidant gas supply communication hole 32a. A fuel gas such as a hydrogen-containing gas is supplied from the fuel gas supply connection pipe 56a of the first end plate 18a to the fuel gas supply communication hole 34a.

  On the other hand, as shown in FIG. 2, a coolant such as pure water, ethylene glycol, or oil is supplied from the coolant supply connection pipe 86a of the second end plate 18b to the pair of coolant supply passages 36a.

  Thereby, as shown in FIG. 3, the oxidant gas is introduced into the oxidant gas flow path 44 of the first metal separator 28 from the oxidant gas supply communication hole 32 a. The oxidant gas moves in the direction of arrow A along the oxidant gas flow path 44 and is supplied to the cathode electrode 40 of the electrolyte membrane / electrode structure 26.

  On the other hand, the fuel gas is supplied to the fuel gas flow path 46 of the second metal separator 30 from the fuel gas supply communication hole 34a. The fuel gas moves in the direction of arrow A along the fuel gas flow path 46 and is supplied to the anode electrode 42 of the electrolyte membrane / electrode structure 26.

  Therefore, in the electrolyte membrane / electrode structure 26, the oxidizing gas supplied to the cathode electrode 40 and the fuel gas supplied to the anode electrode 42 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Done.

  Next, the oxidant gas supplied to and consumed by the cathode electrode 40 of the electrolyte membrane / electrode structure 26 circulates in the direction of arrow B along the oxidant gas discharge communication hole 32b, and from the oxidant gas discharge connection pipe 54b. It is discharged (see FIG. 1). On the other hand, the fuel gas supplied to and consumed by the anode electrode 42 of the electrolyte membrane / electrode structure 26 flows in the direction of arrow B along the fuel gas discharge communication hole 34b and is discharged from the fuel gas discharge connection pipe 56b. .

  The cooling medium supplied to the pair of cooling medium supply communication holes 36 a is introduced into the cooling medium flow path 48 between the first metal separator 28 and the second metal separator 30. The cooling medium once flows in the direction of arrow C and then moves in the direction of arrow A to cool the electrolyte membrane / electrode structure 26. The cooling medium moves outward in the direction of arrow C, then flows in the direction of arrow B along the pair of cooling medium discharge communication holes 36b, and is discharged from the cooling medium discharge connecting pipe 86b (see FIG. 2).

  In this case, in this embodiment, as shown in FIGS. 4 and 5, the oxidant gas supply connection pipe 54 a has an opening cross-sectional area W1 of the pipe intermediate part 70, an opening cross-sectional area W2 of the oxidant gas inlet 66, and oxidation. It is set to a value larger than the opening cross-sectional area W3 of the agent gas outlet 68 (W1> W2, W1> W3).

  For this reason, the pressure loss of the oxidant gas is suppressed as much as possible in the oxidant gas supply connecting pipe 54a. Therefore, an effect is obtained that the oxidant gas can be smoothly and reliably circulated from the external pipe to the oxidant gas supply communication hole 32a via the oxidant gas supply connection pipe 54a.

  Here, the opening cross-sectional area of the pipe intermediate portion 70 has the same value as the opening cross-sectional area of the oxidant gas inlet 66, and the opening cross-sectional shape of the pipe intermediate portion 70 and the opening cross-sectional shape of the oxidant gas inlet 66 are the same. Using an oxidant gas supply connection pipe (hereinafter referred to as a comparative example) having a different shape, an experiment was performed to compare the pressure loss with the oxidant gas supply connection pipe 54a of the present embodiment. The result is shown in FIG.

  As a result, in the comparative example, the internal pressure loss rapidly increases as the pipe length becomes longer, whereas in the present embodiment, the result that the increase in pressure loss is well suppressed is obtained. It was. The same applies to the fuel gas supply connection pipe 56a and the cooling medium supply connection pipe 86a described below.

  In this embodiment, as shown in FIGS. 6 and 7, the fuel gas supply connecting pipe 56 a has an opening cross-sectional area W4 of the pipe intermediate portion 84, an opening cross-sectional area W5 of the fuel gas inlet 80, and a fuel gas outlet 82. Are set to values larger than the opening cross-sectional area W6 (W4> W5, W4> W6).

  For this reason, the pressure loss of the fuel gas is suppressed as much as possible in the fuel gas supply connecting pipe 56a. Therefore, the fuel gas can be smoothly and reliably circulated from the external pipe to the fuel gas supply communication hole 34a via the fuel gas supply connection pipe 56a. In particular, in the fuel gas supply connecting pipe 56a, even when the main body 78 is curved and formed at an angle of approximately 90 °, the internal pressure loss does not increase and the fuel gas can be distributed well. Is done.

  Furthermore, in the present embodiment, as shown in FIG. 8, the cooling medium supply connecting pipe 86 a has a total intermediate part opening cross-sectional area 2 × W7 of each pipe intermediate part 102 and an opening cross-sectional area W8 of the cooling medium inlet 98 and The total outlet side opening sectional area of each cooling medium outlet 100 is set to a value larger than 2 × W9 (2 × W7> W8, 2 × W7> 2 × W9).

  Thereby, the pressure loss of the cooling medium is suppressed as much as possible in the cooling medium supply connecting pipe 86a. For this reason, the effect that it becomes possible to distribute | circulate a cooling medium smoothly and reliably from the external piping via the cooling medium supply connection piping 86a to the cooling medium supply communication hole 36a is acquired.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 12 ... Fuel cell 18a, 18b ... End plate 26 ... Electrolyte membrane electrode assembly 28, 30 ... Metal separator 32a ... Oxidant gas supply communication hole 32b ... Oxidant gas discharge communication hole 34a ... Fuel gas supply Communication hole 34b ... Fuel gas discharge communication hole 36a ... Cooling medium supply communication hole 36b ... Cooling medium discharge communication hole 38 ... Solid polymer electrolyte membrane 40 ... Cathode electrode 42 ... Anode electrode 44 ... Oxidant gas flow path 46 ... Fuel gas flow Channel 48 ... Cooling medium channel 54a ... Oxidant gas supply connection pipe 54b ... Oxidant gas discharge connection pipe 56a ... Fuel gas supply connection pipe 56b ... Fuel gas discharge connection pipe 66 ... Oxidant gas inlet 68 ... Oxidant gas outlet 70 84, 102 ... pipe intermediate part 80 ... fuel gas inlet 82 ... fuel gas outlet 86a ... cooling medium supply connecting pipe 86b ... cold Medium discharge connection pipe 98 ... cooling medium inlet 100 ... coolant outlet

Claims (3)

A fuel cell in which an electrolyte membrane / electrode structure having electrodes provided on both sides of the electrolyte membrane and a separator are stacked; a plurality of the fuel cells are stacked; end plates are disposed at both ends in the stacking direction; In addition, a fluid communication hole for flowing at least a reaction gas or a fluid as a cooling medium is formed in the stacking direction of the fuel cell, and at least one of the end plates has a connection pipe that connects the fluid communication hole and an external pipe. A connected fuel cell stack,
The connecting pipe is configured such that an opening cross-sectional area of a pipe intermediate portion is set to a value larger than an opening cross-sectional area of a fluid inlet and an opening cross-sectional area of a fluid outlet. 2. The fuel cell stack according to claim 1, wherein an inner wall surface of the connection pipe is smoothly formed from the fluid inlet to the pipe intermediate part and from the fluid outlet to the pipe intermediate part. ,
A fuel cell stack comprising only an outwardly curved surface that curves outwardly in a pipe length direction. The fuel cell stack according to claim 1 or 2, wherein the connection pipe integrally includes two of the pipe intermediate portions, the two fluid outlets, and the one fluid inlet.
The total intermediate site opening cross-sectional area, which is the sum of the opening cross-sectional areas of the two pipe intermediate sites, is set to a value larger than the opening cross-sectional area of the fluid inlet,
The total intermediate portion opening cross-sectional area is set to a value larger than a total outlet-side opening cross-sectional area obtained by adding up the opening cross-sectional areas of the two fluid outlets.

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