JP2012018859A - Fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell stack with a simple and compact structure, capable of reliably preventing liquid junction, and capable of ensuring excellent power generation performance.SOLUTION: A humidifier 36 is directly fixed to an end plate 62b which is a component of a fuel cell stack 10. The humidifier 36 comprises a humidifier joint 101 which is attached to the end plate 62b and has an off-gas inlet 40 which introduces off-gas into the humidifier 36, and resin-made piping 112 which is received in the humidifier joint 101 and has an off-gas introducing opening 114 which communicates with an oxidant gas outlet continuous hole 72b and an off-gas discharging opening 116 which communicates with the off-gas inlet 40. The wall of the resin-made piping 112 forming the off-gas introducing opening 114 is provided with a guide 118 which discharges the off-gas in the direction of separating from an inner wall surface 40b which forms the off-gas inlet 40.

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. 13, 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, 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 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 connected to an end plate, and is accommodated in a humidifier joint portion having a reaction gas inlet for introducing a reaction gas into the humidifier, and inside the humidifier joint portion. And an electrically insulating pipe having a reaction gas introduction opening communicating with the reaction gas inlet and a reaction gas outlet opening communicating with the reaction gas inlet.

  A guide portion that guides the reaction gas in a direction away from the inner wall surface that forms the reaction gas inlet is provided on the wall portion of the electrically insulating pipe that forms the reaction gas extraction opening.

  Moreover, it is preferable that a guide part is comprised by the acute angle shape part which formed the end surface of the wall part in acute angle shape.

  Furthermore, it is preferable that the acute-angle-shaped portion is formed with a recess by cutting into the inside of the wall portion.

  Furthermore, it is preferable that the guide portion is constituted by a return portion in which the wall portion is bent or curved toward the reaction gas outlet opening portion side.

  According to the present invention, the reaction gas introduced into the electrically insulating pipe constituting the humidifier joint portion from the reaction gas discharge communication hole is led out to the reaction gas inlet from the reaction gas lead-out opening. At this time, a guide portion is provided on the wall portion that forms the reaction gas outlet opening, and the reaction gas is separated from the inner wall surface that forms the reaction gas inlet under the guiding action of the guide portion. Can be derived.

  For this reason, it is possible to prevent the liquid droplets from staying in the reaction gas outlet opening of the electrically insulating pipe and causing the liquid to be connected 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.

  Thereby, with a simple and compact structure, it can prevent reliably that a liquid junction arises from a fuel cell stack, and can ensure favorable electric 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 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 a partially expanded explanatory view of the resin pipe. It is a partially expanded explanatory view of resin piping which constitutes a fuel cell stack concerning a 2nd embodiment of the present invention. It is a partially expanded explanatory view of resin piping which constitutes a fuel cell stack concerning a 3rd embodiment of the present invention. It is a partially expanded explanatory view of resin piping which constitutes a fuel cell stack concerning a 4th embodiment of the present invention. It is principal part cross-sectional explanatory drawing of the fuel cell stack which concerns on the 5th Embodiment of this invention. It is a partially expanded explanatory view of resin piping which constitutes the fuel cell stack. 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 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 (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, the connecting pipe 110 made of resin 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. A gap S is provided between the outer peripheral portion of the other end 112b of the resin pipe 112 and the inner wall portion 101a of the humidifier joint portion 101 (see FIG. 4).

  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 guide portion 118 that guides off-gas in a direction away from the inner wall surface 40 b that forms the off-gas inlet 40 is provided on the wall portion of the resin pipe 112 that forms the off-gas outlet opening 116.

  The guide part 118 is configured by an acute-angle shaped part 118a in which the end surface of the wall part is formed into an acute angle. On the outer surface side of the acute-angle shaped portion 118a, a recess 118b is formed by cutting into the inside of the wall portion. In addition, the guide part 118 should just be provided in at least 3 sides of a wall part, and may be provided in the edge | side at the end 112a side as needed. In addition, as indicated by a two-dot chain line in FIG. 5, the guide portion 118 may be configured such that the tip end portion of the acute-angle shaped portion 118 a protrudes into the off-gas inlet 40. The distance SI between the pair of guide portions 118 is set to be smaller than the opening diameter SH of the off gas inflow port 40.

  A drain hole 120 is formed in a predetermined direction, for example, in the direction of gravity, at the lowermost position of the outer periphery of the other end 112b. As shown in FIG. 4, the ring-shaped wall portion forming the drain hole 120 is formed with a recess 120 a so that the ring-shaped wall portion forms an acute-angled portion. The drain hole portion 120 communicates with the drainage chamber 121 of the humidifier joint portion 101, while the drainage chamber 121 communicates with the diluter 57 from the dilution channel 41 via the drainage pipe 122 (see FIG. 1).

  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 FIG. 4).

  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 the first embodiment, as shown in FIG. 4, the end plate 62 b and the humidifier joint portion 101 are connected via a resin pipe 112. The other end 112b on the small diameter side of the resin pipe 112 enters the off gas inlet 40, and an off gas outlet opening 116 communicating with the off gas inlet 40 is formed at the other end 112b.

  A guide portion 118 that guides off-gas in a direction away from the inner wall surface 40 b that forms the off-gas inlet 40 is provided on the wall of the resin pipe 112 that forms the off-gas outlet opening 116. The guide portion 118 is constituted by an acute angle shape portion 118a in which the end surface of the wall portion is formed in an acute angle shape.

  Therefore, as shown in FIG. 7, the off-gas can be led out in a direction away from the inner wall surface 40b forming the off-gas inflow port 40 under the guiding action of the acute-angle shaped portion 118a. For this reason, it becomes possible to prevent the off gas from entering the gap S between the guide part 118 and the inner wall surface 40b as much as possible around the tip of the guide part 118 (indicated by the broken line in FIG. 7). reference).

  As a result, it is possible to prevent liquid droplets from staying in the off-gas outlet opening 116 of the resin pipe 112 and causing a liquid connection between the stagnant water and the humidifier joint 101. 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.

  For this reason, with a simple and compact configuration, it is possible to satisfactorily prevent a liquid junction from being generated from the fuel cell stack 10 and to obtain an effect of ensuring good power generation performance.

  Further, a concave portion 118b is formed on the outer surface side of the acute-angle shaped portion 118a by cutting into the inside of the wall portion. Thus, the off gas is more reliably prevented from entering the tip of the guide portion 118, and there is an advantage that the liquid junction is prevented well without causing the liquid connection.

  On the other hand, as shown in FIG. 4, the ring-shaped wall part forming the drain hole 120 is formed with a recess 120a so that the ring-shaped wall part forms an acute-angled part. Therefore, the water droplets discharged from the drain hole 120 to the drain chamber 121 are not attached to and connected to the outer peripheral surface of the bottom of the other end 112b, and the liquid junction can be effectively prevented.

  Note that the guide portion 118 may bulge outward so as to protrude into the off-gas inlet 40. The same applies to the following embodiments.

  FIG. 8 is a partially enlarged explanatory view of a resin pipe (electrically insulating pipe) 130 constituting the fuel cell stack 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 and subsequent embodiments described below, detailed description thereof is omitted.

  A guide portion 132 that guides off-gas in a direction away from the inner wall surface 40 b forming the off-gas inlet 40 is provided on the wall portion of the resin pipe 130 that forms the off-gas outlet opening 116.

  The guide part 132 is constituted by an acute-angle shaped part 132a in which the end surface of the wall part is formed into an acute angle. On the inner surface side of the acute-angle shaped portion 132a, a recess 132b is formed by cutting into the inside of the wall portion.

  FIG. 9 is a partially enlarged explanatory view of a resin pipe (electrically insulating pipe) 140 constituting the fuel cell stack according to the third embodiment of the present invention.

  A guide portion 142 that guides off-gas in a direction away from the inner wall surface 40 b that forms the off-gas inlet 40 is provided on the wall portion of the resin pipe 140 that forms the off-gas outlet opening 116.

  The guide part 142 is configured by an acute-angle shaped part 142a in which the end surface of the wall part is formed into an acute angle. A concave portion 142b is formed on the outer surface side of the acute-angle shaped portion 142a by being cut into the wall portion, and a concave portion 142c is formed on the inner surface side of the acute-angle shaped portion 142a by being cut into the wall portion. .

  FIG. 10 is a partially enlarged explanatory view of a resin pipe (electrically insulating pipe) 150 constituting the fuel cell stack according to the fourth embodiment of the present invention.

  A guide portion 152 that guides off-gas in a direction away from the inner wall surface 40 b that forms the off-gas inlet 40 is provided on the wall portion of the resin pipe 150 that forms the off-gas outlet opening 116.

  The guide part 152 is configured by an acute-angle shaped part 152a in which the end surface of the wall part is formed into an acute angle. An inclined surface 152b is formed on the end surface of the acute-angle shaped portion 152a.

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

  FIG. 11 is an explanatory cross-sectional view of a main part of a fuel cell stack 160 according to the fifth embodiment of the present invention.

  The fuel cell stack 160 includes a resin pipe (electrically insulating pipe) 162. On the wall portion of the resin pipe 162 that forms the off-gas outlet opening 116, a guide portion 164 that guides off-gas in a direction away from the inner wall surface 40b that forms the off-gas inlet 40 is provided.

  The guide portion 164 includes a return portion 164a in which a wall portion of the resin pipe 162 is bent or curved toward the off-gas outlet opening 116 side. As shown in FIG. 12, the guide portion 164 has a flat surface 164 b inside the resin pipe 162. Note that a curved surface may be provided instead of the flat surface 164b.

  In the fifth embodiment configured as described above, the same effects as in the first to fourth embodiments can be obtained.

DESCRIPTION OF SYMBOLS 10,160 ... 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 cells 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 polymer electrolyte membrane 80 ... Anode side electrode 82 ... Cathode side electrode 84 ... Fuel gas flow path 86 ... Cooling Body channel 88 ... Oxidant gas channel 101 ... Humidifier joints 102a, 102b ... Humidifier 110 ... Resin connecting piping 112, 130, 140, 150, 162 ... Resin piping 112a ... One end 112b ... Other end 114 ... Off-gas introduction opening 116: Off-gas outlet opening 118, 132, 142, 152, 164 ... Guide part 118a, 132a, 142a, 152a ... Acute angle shape part 118b, 120a, 132b, 142b, 142c ... Recess 120 ... Drain hole part 152b ... Inclined surface 164a ... Return part

Claims (4)

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;
With
The wall portion of the electrically insulating pipe that forms the reaction gas outlet opening is provided with a guide portion that guides the reaction gas away from the inner wall surface that forms the reaction gas inlet. And fuel cell stack.   2. The fuel cell stack according to claim 1, wherein the guide portion is configured by an acute angle shape portion in which an end surface of the wall portion is formed in an acute angle shape.   3. The fuel cell stack according to claim 2, wherein the acute-angled portion is cut into the wall portion to form a recess.   2. The fuel cell stack according to claim 1, wherein the guide portion is configured by a return portion in which the wall portion is bent or curved toward the reaction gas outlet opening.

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