JP5430318B2 - Fuel cell stack - Google Patents

Description

  The present invention provides an end plate in which a plurality of power generation cells are stacked and a reaction gas discharge communication hole through which a reaction gas used for a power generation reaction flows in the stacking direction is disposed at one end of the stacking direction Furthermore, the present invention relates to a fuel cell stack to which a humidifier communicating with the reaction gas discharge communication hole is connected.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) in which an anode side electrode and a cathode side electrode are disposed on both sides of an electrolyte membrane made of a polymer ion exchange membrane is sandwiched by separators. It has a power generation cell. This type of fuel cell is usually used as an in-vehicle fuel cell stack, for example, by stacking a predetermined number of power generation cells.

  In a fuel cell stack, an internal manifold is often configured to supply a fuel gas and an oxidant gas, which are reaction gases, to the anode side electrode and the cathode side electrode of each stacked power generation cell. The internal manifold includes a reaction gas supply communication hole and a reaction gas discharge communication hole that are provided through the power generation cell in the stacking direction.

  At that time, an external device, for example, a humidifier, communicates with the reaction cell discharge communication hole via the discharge side pipe in the fuel cell stack. For this reason, a minute electric current may flow through the condensed water from the connection portion between the fuel cell stack and the discharge side pipe (liquid junction).

  Thus, in order to suppress this type of liquid junction, for example, a fuel cell system disclosed in Patent Document 1 has been proposed. As shown in FIG. 10, the fuel cell system includes a fuel cell stack 1, and the fuel cell stack 1 includes a stacked body in which a plurality of cell modules 2 are stacked, and both ends of the stacked body in the stacking direction. Are provided with end plates 3a, 3b.

  One end plate 3a is connected to supply pipes 4a, 5a, and 6a for humidified hydrogen gas, humidified air, and coolant, and discharge pipes 4b, 5b, and 6b, respectively. These supply pipes 4a to 6a and discharge pipes 4b to 6b are formed of an electrically insulating member.

JP-A-2005-332673

  However, in the above-mentioned Patent Document 1, the generated water generated by the power generation is condensed and the stagnant water is likely to be generated particularly in the air discharge communication hole (not shown) communicating with the discharge pipe 5b. On the other hand, in a hydrogen gas discharge communication hole (not shown) communicating with the discharge pipe 4b, moisture due to reverse diffusion through the electrolyte membrane of the generated water is easily condensed, and stagnant water is easily generated.

  For this reason, in the discharge pipes 4b and 5b, the condensed water is discharged by the reaction gas discharge pressure, and there is a problem that the metal members are in liquid junction via the condensed water.

  In that case, it is conceivable to increase the insulation resistance by configuring the discharge pipes 4b and 5b to be considerably long. However, since the discharge pipes 4b and 5b are formed of an electrically insulating member, there is a problem in that insufficient strength is likely to occur due to the increase in length, and handling of the external pipes becomes complicated and the pipe structure becomes large. .

  The present invention solves this type of problem, and provides a fuel cell stack capable of reliably preventing liquid junctions and ensuring good power generation performance with a simple and compact configuration. With the goal.

  The present invention provides an end plate in which a plurality of power generation cells are stacked and a reaction gas discharge communication hole through which a reaction gas used for a power generation reaction flows in the stacking direction is disposed at one end of the stacking direction Further, the present invention relates to a fuel cell stack to which a humidifier communicating with the reaction gas discharge communication hole is connected.

The humidifier is provided with a humidifier joint portion that communicates with the reaction gas discharge communication hole and has a reaction gas inlet for introducing the reaction gas into the humidifier. The end plate and the humidifier joint portion include the reaction gas have a reaction gas outlet port communicating with the inlet port, said humidifier with disposed within the joint portion are connected by electrically insulating the pipe entering into the reaction gas inlet mouth, the outer peripheral portion of the electrically insulating pipe A gap for allowing a part of the reaction gas to flow is provided between the inner wall portion of the humidifier joint portion.

  Moreover, it is preferable that the opening cross-sectional area of the reaction gas outlet port of the electrical insulating pipe is set smaller than the flow path cross-sectional area in the electrical insulating pipe.

  Furthermore, it is preferable that the electrically insulating pipe is provided with a reaction gas outlet that is positioned below the reaction gas outlet and introduces the reaction gas into the gap.

  Furthermore, it is preferable that a drain hole is provided at the bottom of the inner wall of the electrically insulating pipe.

  The reactive gas discharge port is preferably inclined in the reactive gas discharge direction with respect to the radial direction of the electrically insulating pipe.

  According to the present invention, a part of the reaction gas discharged from the reaction gas discharge communication hole to the reformer has a gap provided between the outer peripheral portion of the electrically insulating pipe and the inner wall portion of the humidifier joint portion. Circulate. For this reason, it is possible to prevent liquid droplets from staying at the reaction gas outlet of the electrically insulating piping and causing a liquid connection between the staying water and the humidifier joint.

  Accordingly, there is no formation of a conductive (liquid junction) path that continues from the fuel cell stack to the outside via the conductive portion. Accordingly, it is possible to satisfactorily prevent the occurrence of liquid junction from the fuel cell stack with a simple and compact configuration, and to ensure good power generation performance.

1 is a schematic configuration diagram of a fuel cell system incorporating a fuel cell stack according to a first embodiment of the present invention. It is a disassembled perspective explanatory drawing of the power generation cell which comprises the said fuel cell stack. It is a perspective explanatory view of the humidifier and the fuel cell stack which constitute the fuel cell system. It is a partial sectional view showing the inside of the humidifier. It is principal part sectional drawing of the said fuel cell stack. It is front explanatory drawing of resin piping which comprises the said fuel cell stack. It is a perspective explanatory view of the resin piping. It is principal part cross-sectional explanatory drawing of the fuel cell stack which concerns on the 2nd Embodiment of this invention. It is principal part cross-sectional explanatory drawing of the fuel cell stack which concerns on the 3rd Embodiment of this invention. 1 is a schematic explanatory diagram of a fuel cell system disclosed in Patent Document 1. FIG.

  As shown in FIG. 1, a fuel cell system 12 incorporating a fuel cell stack 10 according to the first embodiment of the present invention is mounted on a fuel cell vehicle (not shown). The fuel cell system 12 includes a fuel cell stack 10, a cooling medium supply mechanism 16 for supplying a cooling medium to the fuel cell stack 10, and an oxidant gas (reactive gas) for supplying the fuel cell stack 10. An oxidant gas supply mechanism 18 and a fuel gas supply mechanism 20 for supplying fuel gas (reactive gas) to the fuel cell stack 10 are provided.

  The cooling medium supply mechanism 16 includes a radiator 24. A cooling medium supply pipe 28 and a cooling medium discharge pipe 30 are connected to the radiator 24 via a refrigerant pump 26.

  The oxidant gas supply mechanism 18 includes an air pump 32, and an air supply pipe 34 connected at one end to the air pump 32 is connected at the other end to the humidifier 36. The fuel cell stack 10 is connected via the humidified air supply pipe 38.

  The humidifier 36 is provided with an off-gas inlet (reactive gas inlet) 40 for supplying an oxidizing gas (hereinafter referred to as off-gas) containing used product water from the fuel cell stack 10 as a humidified fluid. In the humidifier 36, a back pressure valve 42 is disposed on the discharge side of the off gas supplied through the off gas inlet 40.

  The fuel gas supply mechanism 20 includes a fuel gas tank (fuel tank) 44 in which hydrogen gas is stored as fuel gas. One end of a fuel gas supply pipe 45 is connected to the fuel gas tank 44, and a cutoff valve 46, a regulator 48 and an ejector 50 are connected to the fuel gas supply pipe 45, and the ejector 50 is connected to the fuel cell stack 10. Connected to.

  An exhaust fuel gas pipe 52 for discharging used fuel gas is connected to the fuel cell stack 10. The exhaust fuel gas pipe 52 is connected to the ejector 50 via a return pipe 54 and partly communicates with the diluter 57 from the purge valve 56. Dilution air and dew condensation water from the humidifier 36 can be supplied to the diluter 57 via the dilute flow path 41 branched from the off-gas inlet 40.

  The fuel cell stack 10 has a plurality of power generation cells 58 stacked in the horizontal direction (the direction of arrow A in FIGS. 2 and 3), which is the vehicle length direction, and terminal plates 59a, 59b and Metal end plates 62a and 62b are disposed via insulating plates 60a and 60b (see FIG. 1). Electric power extraction terminals 63a and 63b protrude outward from the terminal plates 59a and 59b in the stacking direction, and the electric power extraction terminals 63a and 63b are connected to a vehicle driving motor and auxiliary equipment (not shown).

  As shown in FIG. 2, each power generation cell 58 includes an electrolyte membrane / electrode structure 66 and first and second separators 68 and 70 that sandwich the electrolyte membrane / electrode structure 66, and is configured to be vertically long. Is done. In addition, the 1st and 2nd separators 68 and 70 are comprised with a carbon separator or a metal separator.

  One end edge (upper end edge) of the power generation cell 58 in the long side direction (arrow C direction) communicates with each other in the arrow A direction to supply an oxidant gas, for example, an oxygen-containing gas. A supply communication hole 72a and a fuel gas supply communication hole 76a for supplying a fuel gas, for example, a hydrogen-containing gas, are provided.

  The other end edge (lower end edge) in the long side direction of the power generation cell 58 communicates with each other in the direction of the arrow A to discharge an oxidant gas (reactive gas discharge communication hole). 72b and a fuel gas discharge communication hole (reaction gas discharge communication hole) 76b for discharging the fuel gas are provided.

  A cooling medium supply communication hole 74a for supplying a cooling medium is provided at one end edge of the power generation cell 58 in the short side direction (arrow B direction), and the other end edge of the power generation cell 58 in the short side direction. Is provided with a cooling medium discharge communication hole 74b for discharging the cooling medium. The cooling medium supply communication hole 74a and the cooling medium discharge communication hole 74b are set in a vertically long shape.

  The electrolyte membrane / electrode structure 66 includes, for example, a solid polymer electrolyte membrane 78 in which a thin film of perfluorosulfonic acid is impregnated with water, and an anode side electrode 80 and a cathode side electrode 82 that sandwich the solid polymer electrolyte membrane 78. With.

  A fuel gas flow path 84 that connects the fuel gas supply communication hole 76 a and the fuel gas discharge communication hole 76 b is formed on the surface 68 a of the first separator 68 facing the electrolyte membrane / electrode structure 66. The fuel gas channel 84 is constituted by, for example, a groove extending in the direction of arrow C. A part of the cooling medium flow path 86 that connects the cooling medium supply communication hole 74 a and the cooling medium discharge communication hole 74 b is formed on the surface 68 b opposite to the surface 68 a of the first separator 68.

  The surface 70a of the second separator 70 facing the electrolyte membrane / electrode structure 66 is provided with, for example, an oxidant gas flow path 88 formed of a groove extending in the direction of arrow C. The oxidant gas supply communication hole 72a and the oxidant gas discharge communication hole 72b communicate with each other. A cooling medium flow path 86 is integrally formed on the surface 70b opposite to the surface 70a of the second separator 70 so as to overlap the surface 68b of the first separator 68. Although not shown, the first and second separators 68 and 70 are provided with seal members integrally or individually.

  As shown in FIG. 3, the fuel cell stack 10 includes a casing 89 having end plates 62a and 62b as end plates, for example. Instead of the casing 89, the end plates 62a and 62b may be connected by a tie rod (not shown).

  As shown in FIG. 1, the end plate 62a is provided with a cooling medium inlet 96a and a cooling medium outlet 96b. The cooling medium inlet 96a communicates with the cooling medium supply communication hole 74a, while the cooling medium outlet 96b communicates with the cooling medium discharge communication hole 74b. The cooling medium inlet 96 a and the cooling medium outlet 96 b communicate with the radiator 24 through the cooling medium supply pipe 28 and the cooling medium discharge pipe 30.

  The end plate 62b has an oxidant gas inlet 98a that communicates with the oxidant gas supply communication hole 72a, a fuel gas inlet 100a that communicates with the fuel gas supply communication hole 76a, and an oxidant gas outlet that communicates with the oxidant gas discharge communication hole 72b. 98 b and a fuel gas outlet 100 b communicating with the fuel gas discharge communication hole 76 b are provided.

  As shown in FIG. 3, the humidifier joint portion 101 constituting the humidifier 36 is directly fixed to the end plate 62 b of the fuel cell stack 10. In the humidifier 36, the first and second humidifiers 102a and 102b are accommodated in a vertical arrangement. The first humidifying unit 102 a and the second humidifying unit 102 b are connected to the air supply pipe 34 and the humidified air supply pipe 38. The first humidifying part 102a and the second humidifying part 102b can adopt, for example, a hollow fiber membrane type humidifying structure.

  As shown in FIG. 4, porous tubes 104 a and 104 b having a large number of holes are arranged at substantially the center in the first humidifying portion 102 a and the second humidifying portion 102 b, and the porous tubes 104 a and 104 b On the outer periphery, a plurality of hollow fiber membranes 106a and 106b extend in the direction of arrow A and are accommodated. Off-gas is supplied into the porous tube bodies 104 a and 104 b in communication with the off-gas inlet 40.

  Air before reaction is supplied into the hollow fiber membranes 106 a and 106 b through the air supply pipe 34. The outlet sides of the hollow fiber membranes 106a and 106b communicate with the humidified air supply pipe 38.

  As shown in FIG. 5, a resin connection pipe 110 is attached to the oxidant gas outlet 98b of the end plate 62b. One end 110a of the resin connection pipe 110 has a rectangular shape corresponding to the outlet shape of the oxidant gas discharge communication hole 72b, while the other end 110b of the resin connection pipe 110 has a ring shape. An electrically insulating pipe, for example, a resin pipe 112 is connected to the other end 110 b of the resin connection pipe 110.

  The end plate 62b and the humidifier joint portion 101 are connected via a resin pipe 112. The resin piping 112 is formed of an insulating material such as polyphenylene sulfide (PPS), for example. The resin pipe 112 may form a resin film on the surface of the metal main body.

  As shown in FIGS. 5 to 7, the resin pipe 112 has a cylindrical shape, and one end 112 a on the large diameter side is inserted into the other end 110 b of the resin connection pipe 110 via an O-ring 114. The other end 112 b on the small diameter side of the resin pipe 112 enters the off-gas inlet 40 of the humidifier joint portion 101. Between the outer peripheral part of the other end 112b of the resin pipe 112 and the inner wall part of the humidifier joint part 101, a gap S for allowing a part of the off gas to flow is provided.

  The off-gas inlet 40 has an inclined channel portion 40a that inclines downward toward the oxidant gas outlet 98b side, and the other end 112b extends at least to an inclination start end of the inclined channel portion 40a. Is set. Instead of the inclined channel portion 40a, a vertical channel portion (not shown) extending in the vertical direction may be used.

  The other end 112b has a predetermined length in the axial direction from the front end edge portion, and is cut out from the upper end to a predetermined length in the diametrical direction to form an off-gas outlet (reactive gas outlet) 116. . The off-gas outlet port 116 is in open communication with the tilt start end of the tilt channel portion 40a. The opening cross-sectional area of the off-gas outlet 116 is set smaller than the cross-sectional area of the flow path in the other end 112b of the resin pipe 112.

  A drain hole 118 is formed in a predetermined direction, for example, in the direction of gravity, at the lowermost position of the outer peripheral portion of the other end 112b. The drain hole 118 communicates with the drainage chamber 120 of the humidifier joint 101, while the drainage chamber 120 communicates with the diluter 57 from the dilution flow path 41 via the drainage pipe 122.

  The drain pipe 122 extends toward the bottom of the humidifier joint 101 in the direction of gravity, but is not limited to this. For example, the drain pipe 122 has a horizontal capacity at the side of the humidifier joint 101. (See the two-dot chain line in FIGS. 5 and 6).

  For example, one off-gas discharge port (reactive gas discharge port) 124 is formed at the lowermost end position of the outer peripheral portion of the other end 112b in front of the drain hole 118 in the off-gas flow (discharge) direction (arrow L2 direction). The off gas discharge port 124 is inclined in the off gas discharge direction (arrow L2 direction) with respect to the radial direction of the other end 112b.

  The operation of the fuel cell system 12 configured as described above will be described below.

  First, as shown in FIG. 1, the air pump 32 constituting the oxidant gas supply mechanism 18 is driven, and external air that is an oxidant gas is sucked and introduced into the air supply pipe 34. This air is introduced into the humidifier 36 from the air supply pipe 34 and supplied to the humidified air supply pipe 38 through the hollow fiber membranes 106a and 106b of the first and second humidifiers 102a and 102b (see FIG. 4). ).

  At that time, off-gas which is an oxidant gas used for the reaction is supplied to the porous tube bodies 104a and 104b via the off-gas inlet 40, as will be described later. For this reason, moisture contained in the off-gas moves to the air before use, and the air before use is humidified. The humidified air is supplied from the humidified air supply pipe 38 to the oxidant gas supply communication hole 72a in the fuel cell stack 10 through the end plate 62b.

  On the other hand, as shown in FIG. 1, in the fuel gas supply mechanism 20, the fuel gas (hydrogen gas) in the fuel gas tank 44 is stepped down by the regulator 48 under the opening action of the shutoff valve 46, and then passes through the ejector 50. The fuel gas supply communication hole 76a in the fuel cell stack 10 is introduced from the end plate 62b.

  Further, in the cooling medium supply mechanism 16, under the action of the refrigerant pump 26, the cooling medium is introduced from the cooling medium supply pipe 28 through the end plate 62 a to the cooling medium supply communication hole 74 a in the fuel cell stack 10.

  As shown in FIG. 2, the air supplied to each power generation cell 58 in the fuel cell stack 10 is introduced into the oxidant gas flow path 88 of the second separator 70 from the oxidant gas supply communication hole 72a, and the electrolyte membrane / It moves along the cathode side electrode 82 of the electrode structure 66. On the other hand, the fuel gas is introduced into the fuel gas flow path 84 of the first separator 68 from the fuel gas supply communication hole 76 a and moves along the anode side electrode 80 of the electrolyte membrane / electrode structure 66.

  Therefore, in each electrolyte membrane / electrode structure 66, the oxygen in the air supplied to the cathode side electrode 82 and the fuel gas (hydrogen) supplied to the anode side electrode 80 undergo an electrochemical reaction in the electrode catalyst layer. To generate electricity.

  Next, the air consumed by being supplied to the cathode side electrode 82 flows along the oxidant gas discharge communication hole 72b, and is then discharged from the end plate 62b to the off gas inlet 40 as an off gas (see FIG. 1).

  At that time, the generated water generated by power generation at the cathode side electrode 82 is introduced into the oxidant gas discharge communication hole 72b. In the oxidant gas discharge communication hole 72b, the generated water introduced to the end plate 62b side is discharged to the off-gas inlet 40 along with the off-gas flow.

  In this case, in the first embodiment, as shown in FIG. 5, the oxidant gas discharge communication hole 72 b and the off-gas inlet 40 are communicated between the end plate 62 b and the humidifier joint portion 101 of the humidifier 36. A resin pipe 112 made of an insulating material is attached.

  The other end 112b on the small-diameter side of the resin pipe 112 enters the off-gas inlet 40, and between the outer peripheral portion of the other end 112b and the inner wall of the humidifier joint portion 101, a portion of off-gas is supplied. A gap S is provided for circulating the part.

  For this reason, part of the off gas discharged into the resin pipe 112 from the oxidant gas discharge communication hole 72 b is introduced into the gap S from the off gas discharge port 124 provided in the resin pipe 112. Since this off gas flows through the gap S and flows into the off gas inlet 40 (see FIGS. 5 and 6), droplets stay in the off gas inlet 40 and the water stays between the stagnant water and the humidifier joint portion 101. It is possible to prevent the liquid from being connected to the liquid.

  At that time, the off-gas outlet 124 is inclined in the off-gas discharge direction with respect to the radial direction of the other end 112b. This makes it possible to smoothly and reliably lead off gas from the off gas discharge port 124 toward the gap S.

  Accordingly, a conductive (liquid junction) path that continues from the inside of the fuel cell stack 10 to the outside via the conductive portion is not formed. Thereby, it is possible to satisfactorily prevent the occurrence of a liquid junction from the fuel cell stack 10 with a simple and compact configuration, and an effect that desired power generation performance can be ensured can be obtained.

  Furthermore, the opening cross-sectional area of the off-gas outlet 116 is set to be smaller than the cross-sectional area of the flow path in the other end 112b of the resin pipe 112. For this reason, the flow rate of off gas at the off gas outlet 116 is increased, and the flow of off gas from the outer periphery of the other end 112b is promoted by the venturi effect. Therefore, water adhering to the outer periphery of the other end 112b can be forcibly sucked and blown out to the off gas inlet 40. Thereby, the electrically conductive path | route with water and the humidifier joint part 101 can be interrupted | blocked reliably.

  In addition, an off-gas discharge port 124 is formed in the lower end position of the outer peripheral portion of the other end 112b in front of the drain hole 118 in the off-gas flow direction. For this reason, offgas is led out from the offgas discharge port 124 toward the drainage chamber 120, and the water level stored in the drainage chamber 120 is pushed down. Therefore, even if the amount of stored water is relatively large, it is possible to improve insulation.

  Furthermore, the drain hole 118 is provided in the direction of gravity. Thereby, water droplets can be reliably discharged from the other end 112 b toward the drain chamber 120.

  Further, in the resin pipe 112, the other end 112b on the small diameter side is connected to the one end 112a on the large diameter side. For this reason, the step between the one end 112a and the other end 112b can prevent the continuous connection of droplets.

  On the other hand, the consumed fuel gas supplied to the anode side electrode 80 is discharged and flows into the fuel gas discharge communication hole 76b, and is discharged from the end plate 62b to the discharged fuel gas pipe 52 as the discharged fuel gas (FIG. 1). reference). Part of the discharged fuel gas discharged to the discharged fuel gas pipe 52 is returned to the fuel gas supply pipe 45 through the return pipe 54 under the suction action of the ejector 50.

  The discharged fuel gas is mixed with new fuel gas and supplied into the fuel cell stack 10 from the fuel gas supply pipe 45. The remaining discharged fuel gas is discharged under the action of opening the purge valve 56.

  As shown in FIG. 2, the cooling medium is introduced into the cooling medium flow path 86 between the first and second separators 68 and 70 from the cooling medium supply communication hole 74 a and then flows along the arrow B direction. . After cooling the electrolyte membrane / electrode structure 66, the cooling medium moves through the cooling medium discharge communication hole 74b and is discharged from the cooling medium outlet 96b of the end plate 62a to the cooling medium discharge pipe 30. As shown in FIG. 1, the cooling medium is cooled by the radiator 24 and then supplied from the cooling medium supply pipe 28 to the fuel cell stack 10 under the action of the refrigerant pump 26.

  FIG. 8 is an explanatory cross-sectional view of a main part of a fuel cell stack 130 according to the second embodiment of the present invention.

  The same components as those of the fuel cell stack 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Similarly, in the third embodiment described below, detailed description thereof is omitted.

  The fuel cell stack 130 includes a resin pipe 132 that connects the end plate 62 b and the humidifier joint portion 101. A drain hole 118, a first off-gas discharge port 124a, and a second off-gas discharge port 124b are formed in this order along the off-gas flow direction at the lower end position of the outer peripheral portion 132b on the small-diameter side of the resin pipe 132. . The drain hole 118 extends in the direction of gravity, while the first and second off gas discharge ports 124a and 124b are inclined in the off gas discharge direction.

  In the second embodiment configured as described above, the first and second off-gas discharge ports 124a and 124b are provided, and the off-gas can be more reliably supplied to the gap S. The same effect as in the embodiment can be obtained.

  FIG. 9 is an explanatory cross-sectional view of a main part of a fuel cell stack 140 according to the third embodiment of the present invention.

  The fuel cell stack 140 includes a resin pipe 142 that connects the end plate 62 b and the humidifier joint portion 101. A drain hole 118, a first off-gas discharge port 144a, and a second off-gas discharge port 144b are formed in this order along the off-gas flow direction at the lower end position of the other end 142b on the small-diameter side of the resin pipe 142. . The drain hole 118 extends in the direction of gravity, and the first and second off-gas discharge ports 144a and 144b also extend in the direction of gravity.

  In the third embodiment configured as described above, the first and second off-gas discharge ports 144a and 144b are provided, and the same effects as those of the first and second embodiments can be obtained.

DESCRIPTION OF SYMBOLS 10, 130, 140 ... Fuel cell stack 12 ... Fuel cell system 16 ... Coolant supply mechanism 18 ... Oxidant gas supply mechanism 20 ... Fuel gas supply mechanism 24 ... Radiators 26, 32 ... Pump 28 ... Coolant supply pipe 30 ... Cooling Medium discharge pipe 34 ... Air supply pipe 36 ... Humidifier 38 ... Humidified air supply pipe 40 ... Off gas inlet 44 ... Fuel gas tank 52 ... Exhaust fuel gas pipe 58 ... Power generation cells 62a, 62b ... End plate 66 ... Electrolyte membrane / electrode structure Body 68, 70 ... Separator 72a ... Oxidant gas supply communication hole 72b ... Oxidant gas discharge communication hole 74a ... Cooling medium supply communication hole 74b ... Cooling medium discharge communication hole 76a ... Fuel gas supply communication hole 76b ... Fuel gas discharge communication hole 78 ... Solid polymer electrolyte membrane 80 ... Anode side electrode 82 ... Cathode side electrode 84 ... Fuel gas flow path 8 ... Cooling medium flow path 88 ... Oxidant gas flow path 101 ... Humidifier joint portions 102a, 102b ... Humidification portion 110 ... Resin connection pipes 112, 132, 142 ... Resin pipe 112a ... One end 112b ... Other end 118 ... Drain hole Portion 120 ... Drain chamber 122 ... Drain piping 124, 124a, 124b, 144a, 144b ... Off-gas outlet

Claims (5)

A plurality of power generation cells are stacked, and a reaction gas discharge communication hole through which reaction gas used for power generation reaction flows in the stacking direction is provided, and the reaction is performed on an end plate disposed at one end of the stacking direction. A fuel cell stack to which a humidifier communicating with the gas discharge communication hole is connected,
The humidifier is provided with a humidifier joint portion that communicates with the reaction gas discharge communication hole and has a reaction gas inlet for introducing the reaction gas into the humidifier.
The A end plate and the humidifier joints, have a reaction gas outlet port communicating with the reaction gas inlet, the electrically insulating pipe entering into the reaction gas inlet mouth is disposed in the humidifier joints And connected
A fuel cell stack, wherein a gap for allowing a part of the reaction gas to flow is provided between an outer peripheral portion of the electrically insulating pipe and an inner wall portion of the humidifier joint portion.   2. The fuel cell stack according to claim 1, wherein an opening cross-sectional area of the reaction gas outlet port of the electrically insulating pipe is set smaller than a cross-sectional area of a flow path in the electrically insulating pipe. Fuel cell stack.   3. The fuel cell stack according to claim 1, wherein the electrically insulating pipe is provided with a reactive gas outlet that is positioned below the reactive gas outlet and introduces the reactive gas into the gap. 4. A fuel cell stack characterized by that.   The fuel cell stack according to any one of claims 1 to 3, wherein a drain hole is provided in a bottom portion of the inner wall of the electrically insulating pipe.   5. The fuel cell stack according to claim 3, wherein the reactive gas discharge port is inclined in a reactive gas discharge direction with respect to a radial direction of the electrically insulating pipe. 6.

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