JP5404542B2 - 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 continuous 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. 11, 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-described Patent Document 1, the generated water generated by the power generation is condensed and the accumulated water is likely to be generated especially 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, the condensed water is discharged by the reaction gas discharge pressure in the discharge pipes 4b and 5b, and there is a problem that the metal members are in liquid junction due to the continuous 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 has a simple and compact configuration, can improve drainage, reliably prevent liquid junctions, and can ensure good power generation performance. An object is to provide a battery stack.

  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.

  In this fuel cell stack, a humidifier is connected to an end plate, and is contained in a humidifier joint portion having a reaction gas inlet for introducing a reaction gas into the humidifier, and inside the humidifier joint portion. An electrically insulating pipe having a reactive gas introduction opening communicating with the gas exhaust communication hole and a reactive gas outlet opening communicating with the reactive gas inlet; and the electrically insulating pipe disposed below the electrically insulating pipe A drainage container having a drainage opening for containing moisture discharged from the drainage, and a drainage pipe connected to the drainage container and discharging the moisture to the outside from the drainage opening.

  In addition, a plurality of holes that open into a region of the drainage opening in a plan view when viewed from above are formed in communication with the drainage opening at the lower part of the electrically insulating pipe.

  In this fuel cell stack, it is preferable that the plurality of holes are distributed and formed in the region having a planar shape in a top view and spaced apart at the same interval.

  According to the present invention, the reaction gas introduced into the electrically insulating pipe from the reaction gas discharge communication hole is led out from the reaction gas lead-out opening to the reaction gas inlet of the humidifier joint. On the other hand, the moisture introduced into the electrically insulating pipe passes through a plurality of holes formed in the lower part of the electrically insulating pipe and is discharged to a drainage container disposed at the lower part of the electrically insulating pipe. Furthermore, the water | moisture content discharged | emitted by the drainage container is discharge | released outside the said drainage container through drainage piping.

  At this time, the plurality of holes are opened in a region having a planar shape in a top view of the drainage opening. Therefore, even if the load state changes, such as when the load is low or high, the drainage can be satisfactorily drained from the plurality of holes to the drainage opening in the drainage container, and the drainage opening is unevenly distributed. Thus, it is possible to reliably prevent the stagnant water from being caused.

  For this reason, the water | moisture content discharged | emitted by the drainage container is discharge | released favorably and reliably to the exterior of the said drainage container through drainage piping. Thereby, water does not stay in the drainage container, and a conductive (liquid junction) path that continues from the inside of the fuel cell stack to the outside through the conductive portion is not formed.

  Therefore, with a simple and compact configuration, it is possible to reliably prevent the occurrence of liquid junction from the fuel cell stack 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 principal part sectional drawing of the said fuel cell stack. It is bottom face explanatory drawing of resin piping which comprises the said fuel cell stack. It is a perspective explanatory view of the resin piping. It is bottom face explanatory drawing of resin piping which comprises the fuel cell stack which concerns on the 2nd Embodiment of this invention. It is bottom face explanatory drawing of resin piping which comprises the fuel cell stack which concerns on the 3rd Embodiment of this invention. It is bottom face explanatory drawing of resin piping which comprises the fuel cell stack which concerns on the 4th Embodiment of this invention. It is bottom face explanatory drawing of resin piping which comprises the fuel cell stack which concerns on the 5th 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, the fuel cell system 12 incorporating the fuel cell stack 10 according to the first embodiment of the present invention is mounted on, for example, a fuel cell vehicle (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. An air supply pipe 34 having one end connected to the air pump 32 is connected to the humidifier 36, and the fuel cell stack 10 is connected to the humidifier 36 via a humidified air supply pipe 38. The

  The humidifier 36 is provided with an off-gas inlet (reactive gas inlet) 40 for supplying an oxidizing gas (hereinafter also referred to as off-gas) containing used product water as a humidified fluid from the fuel cell stack 10. . 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 (H ₂ 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.

  In the fuel cell stack 10, a plurality of power generation cells 58 are stacked in the horizontal direction (the direction of arrow A in FIGS. 2 and 3) or the vertical direction (the direction of arrow C in FIG. 2). At both ends in the direction, metal end plates 62a and 62b are disposed via terminal plates 59a and 59b and 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, a drainage container 104 is integrally formed at the bottom of the humidifier joint portion 101 so as to be positioned below a resin pipe 112 described later. The drainage container 104 has a drainage chamber (drainage opening) 106 for storing moisture discharged from the resin pipe 112. The drain chamber 106 is provided with a drain port 106a and communicates from the dilution channel 41 to the diluter 57 via a drain pipe 108 connected to the drain port 106a (see FIG. 1). The drainage port 106a is provided at the lower end position of the side part of the drainage container 104 and on the distal end side (arrow L direction) of the humidifier joint part 101 (see FIG. 4). As shown in FIG. 5, the drain pipe 108 is provided in a direction in which the discharged off gas flows in the humidifier joint portion 101 in order to smoothly discharge water. The position of the drain pipe 108 in the arrow S direction can be changed by the arrangement of peripheral devices.

  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. 4 to 6, 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 113. An off-gas introduction opening (reaction gas introduction opening) 114 communicating with the oxidant gas discharge communication hole 72b is formed at the one end 112a (see FIG. 4).

  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. 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 edge of the tip, and is cut out from the upper end to a predetermined length in the diametrical direction to form an off-gas outlet opening (reactive gas outlet opening) 116. Is done.

  A plurality of, for example, four holes 118a to 118d are provided at the lowermost position of the outer peripheral portion of the other end 112b. As shown in FIG. 5, the holes 118 a to 118 d open into a region having a planar shape (circular shape) in a top view of the drainage chamber 106, specifically, the center O of the drainage chamber 106 within the region. Are distributed at the same angular interval (90 °) from each other. The holes 118a to 118d are preferably set in a circular shape.

  The holes 118 a to 118 d are set to have a diameter φd, and the holes 118 a to 118 d are separated from the outer peripheral surface of the drain chamber 106 by a distance d or more. In addition to the circular shape, the planar shape of the drain chamber 106 in a top view can be set to various shapes such as a polygonal shape such as a square shape and an oval shape.

  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 first and second humidifiers 102a and 102b (see FIG. 3).

  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 1st Embodiment, as shown in FIG. 4, four hole part 118a-118d is provided in the outer peripheral part lowest end position of the other end 112b of the resin piping 112. As shown in FIG. For this reason, the moisture introduced into the resin pipe 112 passes through a plurality of holes 118 a to 118 d formed in the lower part of the resin pipe 112 and is disposed in the lower part of the resin pipe 112. Have been discharged. Further, the water discharged to the drainage container 104 is discharged to the diluter 57 from the outside of the drainage container 104, that is, from the dilution flow path 41 through the drainage pipe 108.

  At that time, the holes 118a to 118d are opened in a region of the drain chamber 106 having a planar shape as viewed from above, as shown in FIG. Therefore, even if the load state changes such as when the load is low or high, the drainage chamber 106 can drain well from the plurality of holes 118a to 118d into the drainage chamber 106 in the drainage container 104. Thus, it is possible to reliably prevent the stagnant water from being unevenly distributed.

  For example, in the case where a single hole is provided corresponding to the center O of the drainage chamber 106, the end away from the drainage port 106a, that is, the farthest side of the drainage port 106a due to an increase in the flow velocity particularly at high loads. It becomes unevenly distributed on the part side and stagnant water is likely to occur. Therefore, by providing a plurality of holes 118a to 118d, the flow rate of off-gas is reduced as compared with a configuration in which a single large-diameter hole is provided, while the amount of water droplets is equalized and unevenly stagnant water is caused. I will not let you.

  For this reason, the water discharged to the drainage container 104 is discharged well and reliably to the outside of the drainage container 104 through the drainage pipe 108. As a result, it is possible to prevent water from staying in the drainage container 104 and forming a conductive (liquid junction) path from the fuel cell stack 10 to the outside through the conductive portion.

  In addition, in the first embodiment, the holes 118a to 118d are formed at the same angular interval from the center O of the drainage chamber 106 within the area of the plan view of the drainage chamber 106 as shown in FIG. Dispersed and formed separately. In addition, the holes 118 a to 118 d are set to have a diameter φd, and the holes 118 a to 118 d are separated from the outer peripheral surface of the drainage chamber 106 by a distance d or more. Accordingly, it is possible to more reliably prevent the stagnant water from being caused in the drain chamber 106 even in various load states from a low load to a high load.

  Accordingly, there is an advantage that it is possible to reliably prevent the occurrence of a liquid junction from the fuel cell stack 10 and to ensure good power generation performance with a simple and compact configuration.

  FIG. 7 is an explanatory bottom view of a resin pipe (electrically insulating pipe) 130 constituting the fuel cell stack according to the second embodiment of the present invention.

  Note that the same components as those of the resin pipe 112 constituting the fuel cell stack according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Similarly, in the third and subsequent embodiments described below, detailed description thereof is omitted.

  Three holes 132 a to 132 c are provided at the lowermost end position of the outer peripheral portion of the other end 130 b having a smaller diameter than the one end 130 a of the resin pipe 130. The holes 132a to 132c open into a region having a planar shape (circular shape) when viewed from the top of the drainage chamber 106. Specifically, the holes 132a to 132c have the same angular interval from the center O of the drainage chamber 106 within the region. 120 °) apart from each other. The holes 132 a to 132 c are set to have a diameter φd, and the holes 132 a to 132 c are separated from the outer peripheral surface of the drainage chamber 106 by a distance d or more.

  FIG. 8 is an explanatory bottom view of a resin pipe (electrically insulating pipe) 140 constituting the fuel cell stack according to the third embodiment of the present invention.

  Five holes 142a to 142e are provided at the lowermost position of the outer peripheral portion of the other end 140b having a smaller diameter than the one end 140a of the resin pipe 140. The holes 142 a to 142 e open in a region (circular shape) in a plan view (circular shape) of the drain chamber 106. Specifically, the four holes 142a to 142d are distributed and formed at the same angular interval (90 °) from the center O of the drainage chamber 106 within the region, and the remaining holes 142e are It is provided at the center O of the drainage chamber 106. The holes 142 a to 142 e are set to a diameter φd, and the holes 142 a to 142 d are separated from the outer peripheral surface of the drainage chamber 106 by a distance d or more.

  FIG. 9 is an explanatory bottom view of a resin pipe (electrically insulating pipe) 150 constituting a fuel cell stack according to the fourth embodiment of the present invention.

  Six holes 152 a to 152 f are provided at the lowermost position of the outer peripheral portion of the other end 150 b having a smaller diameter than the one end 150 a of the resin pipe 150. The holes 152a to 152f open into a region having a planar shape (circular shape) when viewed from the top of the drainage chamber 106. Specifically, the holes 152a to 152f are spaced at the same angular interval from the center O of the drainage chamber 106 within the region. 60 °) apart from each other. The holes 152 a to 152 f are set to have a diameter φd, and the holes 152 a to 152 f are separated from the outer peripheral surface of the drainage chamber 106 by a distance d or more.

  FIG. 10 is an explanatory bottom view of a resin pipe (electrically insulating pipe) 160 constituting the fuel cell stack according to the fifth embodiment of the present invention.

  Seven holes 162 a to 162 g are provided at the lowermost end position of the outer peripheral portion of the other end 160 b having a smaller diameter than the one end 160 a of the resin pipe 160. The holes 162a to 162f open in a region of the drain chamber 106 having a planar shape (circular shape) when viewed from above. Specifically, the six holes 162a to 162f are distributed and formed at the same angular interval (60 °) from the center O of the drainage chamber 106 in the region, and the remaining holes 162g are It is provided at the center O of the drainage chamber 106. The holes 162 a to 162 g are set to a diameter φd, and the holes 162 a to 162 f are separated from the outer peripheral surface of the drainage chamber 106 by a distance d or more.

  In the second to fifth embodiments configured as described above, the same effects as those of the first embodiment can be obtained.

DESCRIPTION OF SYMBOLS 10 ... 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 ... Coolant 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 cell 62a, 62b ... End plate 66 ... Electrolyte membrane / electrode structure 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 height Molecular electrolyte membrane 80 ... Anode side electrode 82 ... Cathode side electrode 84 ... Fuel gas passage 86 ... Cooling medium passage DESCRIPTION OF SYMBOLS 8 ... Oxidant gas flow path 101 ... Humidifier joint part 102a, 102b ... Humidification part 104 ... Drain container 106 ... Drain chamber 108 ... Drain piping 112, 130, 140, 150, 160 ... Resin piping 114 ... Off-gas introduction opening 116: Off-gas outlet openings 118a to 118d, 132a to 132c, 142a to 142e, 152a to 152f, 162a to 162g, holes

Claims (2)

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 connected to the end plate, and has a reaction gas inlet for introducing the reaction gas into the humidifier.
An electrically insulating pipe accommodated in the humidifier joint part, having a reaction gas introduction opening communicating with the reaction gas discharge communication hole and a reaction gas outlet opening communicating with the reaction gas inlet;
A drainage container disposed below the electrically insulating pipe and having a drainage opening for containing moisture discharged from the electrically insulating pipe;
A drainage pipe connected to the drainage container and discharging the moisture to the outside from the drainage opening;
With
A fuel cell characterized in that a plurality of holes that open into a region in a plan view of the drainage opening communicate with the drainage opening at the lower part of the electrically insulating pipe. stack.   2. The fuel cell stack according to claim 1, wherein the plurality of holes are distributed and formed in the region having a planar shape in a top view and spaced apart from each other at the same interval.

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