JP2016085819A - Fuel battery stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely restrict stay of air in a cooling medium manifold by a simple, economical configuration.SOLUTION: A fuel battery stack 10 comprises a second end plate 18b. The second end plate 18b is provided with two cooling-medium supply communication hole 50a, upper and lower. A cooling-medium supply manifold 72a is attached to the second end plate 18b so as to cover each cooling medium supply communication hole 50a. An upper wall 98a is provided in the space 72ac of the cooling medium supply manifold 72a so as to incline from a horizontal direction. A first air removal hole part 100a is formed adjacent to the uppermost part of the upper wall surface 98a.SELECTED DRAWING: Figure 4

Description

  The present invention has a fuel cell in which an electrolyte membrane / electrode structure in which electrodes are provided on both sides of an electrolyte membrane and a separator are stacked in a horizontal direction, and a plurality of the fuel cells are stacked in a horizontal direction. The present invention relates to a fuel cell stack in which an end plate is disposed.

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

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

  The fuel cell further includes a fuel gas communication hole through which fuel gas flows in the stacking direction, an oxidant gas communication hole through which oxidant gas flows, and a cooling medium communication hole through which a cooling medium flows. A manifold type fuel cell is adopted. The fuel gas communication hole has a fuel gas supply communication hole and a fuel gas discharge communication hole, the oxidant gas communication hole has an oxidant gas supply communication hole and an oxidant gas discharge communication hole, and the cooling medium communication hole has And a cooling medium supply communication hole and a cooling medium discharge communication hole.

  In the above internal manifold type fuel cell, at least one end plate is provided with a fluid manifold that supplies or discharges fluid (fuel gas, oxidant gas, or cooling medium) connected to each communication hole. Further, a fluid supply pipe for introducing fluid from the outside or a fluid discharge pipe for leading the fluid to the outside is connected to the fluid manifold.

  Air may be mixed in the cooling medium that is one of the fluids described above. For this reason, there is a problem that air tends to remain in the upper region of the cooling medium manifold (fluid manifold) and cooling efficiency is lowered. Therefore, for example, a fuel cell stack disclosed in Patent Document 1 is known.

  In this fuel cell stack, an end plate communicating with the cooling medium supply communication hole and the cooling medium discharge communication hole is disposed at the end portion in the stacking direction of the stacked body in which the electrolyte membrane / electrode structure and the separator are alternately stacked. ing. A manifold is fixed to the opposite side of the end plate laminate, and an air vent port communicating with the cooling medium supply communication hole is integrated with the cooling medium supply port at a position higher than the cooling medium supply port. Is formed. Furthermore, one end of a piping member is connected to the air vent, the piping member is maintained at a position higher than the air vent, and an open / close valve is mounted at the other end.

  When the cooling medium is supplied to the cooling medium supply port, the air mixed in the cooling medium moves vertically above the cooling medium supply port and is smoothly and reliably discharged from the air vent port. For this reason, air can be effectively prevented from being introduced into the cooling medium supply communication hole, and the cooling efficiency of the entire fuel cell stack is improved satisfactorily with a simple configuration.

Japanese Patent No. 4684585

  The present invention has been made in connection with this type of technology, and provides a fuel cell stack capable of reliably suppressing air from staying inside the cooling medium manifold with a simple and economical configuration. The purpose is to provide.

  The fuel cell stack according to the present invention includes a fuel cell in which an electrolyte membrane / electrode structure provided with electrodes on both sides of an electrolyte membrane and a separator are stacked in a horizontal direction, and the plurality of fuel cells are stacked in a horizontal direction. Has been. At both ends in the stacking direction, end plates are disposed, and between the separators adjacent to each other, a cooling medium flow path for circulating the cooling medium along the separator surface is formed.

  On the inlet side of the cooling medium flow path, a pair of upper and lower cooling medium supply communication holes are provided with the cooling medium flow path sandwiched in the flow path width direction. On the outlet side of the cooling medium flow path, a pair of upper and lower cooling medium discharge communication holes are provided with the cooling medium flow path sandwiched in the flow path width direction.

  One end plate is provided with a cooling medium manifold that communicates with a pair of upper and lower cooling medium supply communication holes or a pair of upper and lower cooling medium discharge communication holes. Inside the cooling medium manifold, an upper wall surface constituting the ceiling portion is provided inclined from the horizontal direction, and an air vent hole is formed adjacent to the uppermost position of the upper wall surface.

  In the fuel cell stack, the cooling medium manifold may include a cooling medium supply manifold that communicates with the pair of upper and lower cooling medium supply communication holes, and a cooling medium discharge manifold that communicates with the pair of upper and lower cooling medium discharge communication holes. preferable. In that case, it is preferable that the upper wall surface provided in the cooling medium supply manifold and the upper wall surface provided in the cooling medium discharge manifold are inclined upward in a direction away from each other.

  Further, in this fuel cell stack, it is preferable that the cooling medium supply manifold is provided with a cooling medium inlet conduit at a central portion in the flow path width direction on a side portion close to the cooling medium discharge manifold. On the other hand, it is preferable that the cooling medium discharge manifold is provided with a cooling medium outlet pipe line at a central portion in the flow path width direction on a side portion that is separated from the cooling medium supply manifold.

  Furthermore, in this fuel cell stack, it is preferable that the cooling medium inlet pipe is inclined downward with respect to the cooling medium flow direction of the cooling medium flow path.

  According to the present invention, the upper wall surface constituting the ceiling portion is provided in the cooling medium manifold so as to be inclined from the horizontal direction. For this reason, the air introduced into the cooling medium manifold flows to the uppermost position side of the upper wall surface along the inclination of the upper wall surface.

  At that time, an air vent hole is formed adjacent to the uppermost position of the upper wall surface. Therefore, the air that has flowed to the uppermost position along the upper wall surface is smoothly discharged to the outside of the fluid manifold from the air vent hole.

  Accordingly, it is possible to reliably suppress air from staying inside the cooling medium manifold with a simple and economical configuration. For this reason, the cooling medium can smoothly and evenly flow from the pair of cooling medium discharge communication holes to the cooling medium manifold while flowing smoothly and evenly to the pair of cooling medium supply communication holes. Therefore, the cooling performance of each fuel cell is improved satisfactorily.

It is a perspective explanatory view from the cooling medium manifold side of the fuel cell stack according to the embodiment of the present invention. It is a partially exploded perspective view of the fuel cell stack. It is a principal part disassembled perspective explanatory drawing of the fuel cell which comprises the said fuel cell stack. FIG. 3 is a front explanatory view from the cooling medium manifold side of the fuel cell stack. It is a disassembled perspective explanatory drawing of the cooling-medium supply manifold and insulating plate which comprise the said fuel cell stack.

  As shown in FIGS. 1 and 2, a fuel cell stack 10 according to an embodiment of the present invention is mounted on, for example, a fuel cell electric vehicle (not shown). The fuel cell stack 10 includes a stacked body 12as in which a plurality of fuel cells 12 are stacked in a horizontal direction (arrow B direction) with an electrode surface in an upright posture.

  As shown in FIG. 2, a first terminal plate 14a, a first insulating plate 16a, and a first end plate 18a are sequentially provided outward at one end in the stacking direction of the fuel cell 12 (one end of the stacked body 12as). Arranged. At the other end in the stacking direction of the fuel cell 12 (the other end of the stacked body 12as), a second terminal plate 14b, a second insulating plate 16b, and a second end plate 18b are sequentially disposed outward. .

  The first power output terminal 20a connected to the first terminal plate 14a faces outward from a substantially central portion (which may be eccentric from the central portion) of the horizontally long (rectangular) first end plate 18a. Extend. The second power output terminal 20b connected to the second terminal plate 14b is directed outward from a substantially central portion (which may be eccentric from the central portion) of the horizontally long (rectangular) second end plate 18b. Extend.

  Between each side of the first end plate 18a and the second end plate 18b, a connecting bar 22 having a certain length corresponding to the substantially central position of each side is arranged. Both ends of the connecting bar 22 are fixed to the first end plate 18a and the second end plate 18b with screws 24, and a tightening load in the stacking direction (arrow B direction) is applied to the stacked body 12as.

  The fuel cell stack 10 includes a casing 26 as necessary. The casing 26 includes a first end plate 18a and a second end plate 18b at two sides (surfaces) at both ends in the vehicle width direction (arrow B direction). Two sides (surfaces) at both ends of the casing 26 in the vehicle length direction (arrow A direction) are constituted by a horizontally long plate-shaped front side panel 28a and rear side panel 28b. Two sides (surfaces) at both ends of the casing 26 in the vehicle height direction (arrow C direction) are constituted by an upper side panel 30a and a lower side panel 30b. The upper side panel 30a and the lower side panel 30b have a horizontally long plate shape.

  The first end plate 18a and the second end plate 18b are provided with screw holes 32 on each side. Hole portions 34 are formed in the front side panel 28a, the rear side panel 28b, the upper side panel 30a, and the lower side panel 30b so as to face the screw holes 32. The screws 36 inserted into the holes 34 are screwed into the screw holes 32, so that the casing 26 is fixed integrally.

  As shown in FIG. 3, the fuel cell 12 includes an electrolyte membrane / electrode structure 40, a first metal separator (cathode side separator) 42 and a second metal separator (anode side) that sandwich the electrolyte membrane / electrode structure 40. Separator) 44.

  The first metal separator 42 and the second metal separator 44 are made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a metal plate that has been subjected to a surface treatment for anticorrosion. The first metal separator 42 and the second metal separator 44 have a rectangular planar shape, and are formed into a concavo-convex shape by pressing a metal thin plate into a wave shape. Instead of the first metal separator 42 and the second metal separator 44, for example, a carbon separator may be used.

  The first metal separator 42 and the second metal separator 44 have a horizontally long shape, and have long sides extending in the horizontal direction (arrow A direction) and short sides extending in the direction of gravity (arrow C direction). Composed. In addition, you may comprise so that a short side may extend in a horizontal direction and a long side may extend in a gravitational direction.

  An oxidant gas supply communication hole 46a and a fuel gas supply communication hole 48a are provided at one end edge of the long side direction (arrow A direction) of the fuel cell 12 so as to communicate with each other in the arrow B direction. The oxidant gas supply communication hole 46a supplies an oxidant gas, for example, an oxygen-containing gas, while the fuel gas supply communication hole 48a supplies a fuel gas, for example, a hydrogen-containing gas.

  The other end edge in the long side direction of the fuel cell 12 communicates with each other in the arrow B direction, and a fuel gas discharge communication hole 48b for discharging the fuel gas, and an oxidant gas for discharging the oxidant gas. A discharge communication hole 46b is provided.

  Two are provided on one side (horizontal one end side) of both ends in the short side direction (arrow C direction) of the fuel cell 12, that is, on the oxidant gas supply communication hole 46a and the fuel gas supply communication hole 48a side. The cooling medium supply communication holes 50a are provided vertically. The cooling medium supply communication holes 50a communicate with each other in the direction of arrow B in order to supply the cooling medium, and two cooling medium supply communication holes 50a are provided on the opposite sides.

  The coolant supply communication hole 50a on the upper side of the fuel cell 12 is divided into two in the horizontal direction, and the coolant is circulated independently of each other. The coolant supply communication hole 50a on the lower side of the fuel cell 12 is divided into two in the horizontal direction, and allows the coolant to flow independently.

  Two cooling medium discharges are respectively provided on the other side (the other end in the horizontal direction) of both ends in the short side direction of the fuel cell 12, that is, on the fuel gas discharge communication hole 48b and the oxidant gas discharge communication hole 46b side. Communication holes 50b are provided on the top and bottom. The cooling medium discharge communication holes 50b communicate with each other in the direction of arrow B in order to discharge the cooling medium, and two cooling medium discharge communication holes 50b are provided on opposite sides. Each cooling medium discharge communication hole 50b is divided into two in the horizontal direction, and allows the cooling medium to flow independently.

  The electrolyte membrane / electrode structure 40 includes, for example, a solid polymer electrolyte membrane 52 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode electrode 54 and an anode electrode 56 that sandwich the solid polymer electrolyte membrane 52. Prepare.

  The cathode electrode 54 and the anode electrode 56 have a gas diffusion layer (not shown) made of carbon paper or the like. The porous carbon particles carrying the platinum alloy on the surface are uniformly applied to the surface of the gas diffusion layer, thereby forming an electrode catalyst layer (not shown). The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 52.

  An oxidant gas flow path 58 that connects the oxidant gas supply communication hole 46 a and the oxidant gas discharge communication hole 46 b is formed on the surface 42 a of the first metal separator 42 facing the electrolyte membrane / electrode structure 40. The oxidant gas channel 58 is formed by a plurality of wavy channel grooves (or linear channel grooves) extending in the direction of arrow A.

  A fuel gas flow path 60 that connects the fuel gas supply communication hole 48 a and the fuel gas discharge communication hole 48 b is formed on the surface 44 a of the second metal separator 44 facing the electrolyte membrane / electrode structure 40. The fuel gas channel 60 is formed by a plurality of wavy channel grooves (or linear channel grooves) extending in the direction of arrow A.

  Between the surface 44b of the second metal separator 44 and the surface 42b of the first metal separator 42 adjacent to each other, the cooling medium flow communicating with the cooling medium supply communication holes 50a and 50a and the cooling medium discharge communication holes 50b and 50b. A path 62 is formed. The cooling medium flow path 62 extends in the horizontal direction and allows the cooling medium to flow over the electrode range of the electrolyte membrane / electrode structure 40.

  A first seal member 64 is integrally formed on the surfaces 42 a and 42 b of the first metal separator 42 around the outer peripheral edge of the first metal separator 42. A second seal member 66 is integrally formed on the surfaces 44 a and 44 b of the second metal separator 44 around the outer peripheral edge of the second metal separator 44.

  As the first seal member 64 and the second seal member 66, for example, EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber or the like, cushion material Alternatively, an elastic seal member such as a packing material is used.

  As shown in FIG. 2, an oxidant gas supply manifold 68a, an oxidant gas discharge manifold 68b, a fuel gas supply manifold 70a, and a fuel gas discharge manifold 70b are attached to the first end plate 18a. The oxidant gas supply manifold 68a, the oxidant gas discharge manifold 68b, the fuel gas supply manifold 70a, and the fuel gas discharge manifold 70b are made of an electrically insulating resin.

  The oxidant gas supply manifold 68a and the oxidant gas discharge manifold 68b communicate with the oxidant gas supply communication hole 46a and the oxidant gas discharge communication hole 46b. The fuel gas supply manifold 70a and the fuel gas discharge manifold 70b communicate with the fuel gas supply communication hole 48a and the fuel gas discharge communication hole 48b.

  As shown in FIG. 1, the second end plate (one end plate) 18b has a resin-made cooling medium supply manifold (cooling medium) that communicates with two (upper and lower) cooling medium supply communication holes 50a. Manifold) 72a is attached. A resin-made cooling medium discharge manifold (cooling medium manifold) 72b communicating with two (a pair of upper and lower) cooling medium discharge communication holes 50b is attached to the second end plate 18b. The cooling medium supply manifold 72a and the cooling medium discharge manifold 72b preferably have electrical insulation.

  As shown in FIGS. 1, 4 and 5, the cooling medium supply manifold 72a is fixed to the second end plate 18b via an insulating plate 74a made of an electrically insulating resin or the like. As shown in FIG. 5, the insulating plate 74 a has a substantially flat plate shape, a cooling medium inlet 76 a integrally communicating with the upper two divided cooling medium supply communication holes 50 a, and a lower divided two cooling medium. A cooling medium inlet 76a that communicates integrally with the supply communication hole 50a.

  The insulating plate 74a is formed with a concave portion 78a having a substantially rectangular shape between the upper and lower cooling medium inlets 76a. A plurality of holes 80a are formed in the outer peripheral edge of the insulating plate 74a.

  As shown in FIGS. 1, 4, and 5, the cooling medium supply manifold 72a has a flange portion 82a that goes around the internal space 72ac. In the flange portion 82a, a plurality of hole portions 84a are formed corresponding to the respective hole portions 80a. The screw 86a inserted into each hole 84a is screwed into a screw hole 88a provided in the second end plate 18b (see FIG. 1), so that the cooling medium supply manifold 72a is attached to the second end plate 18b. Fixed.

  As shown in FIG. 4, an inlet pipe section 90a that is a cooling medium supply port is provided at a substantially central portion of the cooling medium supply manifold 72a (substantially the central portion in the flow path width direction of the cooling medium flow path 62). The inlet pipe section 90a is inclined downward by an angle α1 ° with respect to the coolant flow direction (arrow A direction) (horizontal direction ho) of the coolant flow path 62.

  A convex portion 92a that bulges toward the inlet conduit portion 90a is disposed near the upper coolant supply passage 50a on the inner wall portion of the manifold facing the inlet conduit portion 90a of the coolant supply manifold 72a. . The convex portion 92a is formed to have a smooth curved surface such as a circular arc surface. Convex portions 94a and 96a bulging toward the internal space 72ac are provided on both sides of the inlet pipe portion 90a of the cooling medium supply manifold 72a. Each convex part 94a, 96a is formed with a smooth curved surface such as a circular arc surface.

  In the cooling medium supply manifold 72a, the inlet pipe line portion 90a may be provided near the upper cooling medium supply communication hole 50a. At that time, the angles of the inlet duct portion 90a, the convex portion 92a, and the convex portions 94a and 96a are opposite to the above (see the two-dot chain line in FIG. 4).

  In the internal space 72ac of the cooling medium supply manifold 72a, an upper wall surface 98a constituting the ceiling portion is provided to be inclined at an angle α2 ° from the horizontal direction ho. Specifically, the upper wall surface 98a is inclined upward by an angle α2 ° from the center side of the second end plate 18b toward the outside. A first air vent hole (pipe) 100a is formed (placed) in the cooling medium supply manifold 72a adjacent to the uppermost position of the upper wall surface 98a.

  As shown in FIG. 1, the cooling medium discharge manifold 72b is fixed to the second end plate 18b via an insulating plate 74b made of an electrically insulating resin or the like. Note that the same reference numerals are assigned to the same components as those of the cooling medium supply manifold 72a, and a detailed description thereof will be omitted.

  The cooling medium discharge manifold 72b has an outlet pipe section 90b, which is a cooling medium discharge port, in a substantially central part in the direction of arrow C (the central part in the flow path width direction of the cooling medium flow path 62) in the horizontal direction or Inclined from the horizontal direction.

  As shown in FIG. 4, an upper wall surface 98b constituting the ceiling portion is provided in the internal space 72bc of the cooling medium discharge manifold 72b so as to be inclined by an angle α3 ° from the horizontal direction ho. Specifically, the upper wall surface 98b is inclined upward by an angle α3 ° from the center side of the second end plate 18b toward the outside. The angle α2 ° may be equal to the angle α3 °. In the cooling medium discharge manifold 72b, a second air vent hole (pipe) 100b is formed (placed) adjacent to the uppermost position of the upper wall surface 98b.

  The upper wall surface 98a provided in the internal space 72ac of the cooling medium supply manifold 72a and the upper wall surface 98b provided in the internal space 72bc of the cooling medium discharge manifold 72b are inclined upward in a direction away from each other. The first air vent hole 100a is provided on the side of the cooling medium supply manifold 72a opposite to the side on which the inlet pipe 90a is provided. The second air vent hole portion 100b is provided on the side portion where the outlet pipe portion 90b of the cooling medium discharge manifold 72b is provided.

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

  First, as shown in FIG. 2, an oxidizing gas such as an oxygen-containing gas is supplied from the oxidizing gas supply manifold 68a of the first end plate 18a to the oxidizing gas supply communication hole 46a. A fuel gas such as a hydrogen-containing gas is supplied from the fuel gas supply manifold 70a of the first end plate 18a to the fuel gas supply communication hole 48a.

  Further, as shown in FIG. 1, in the second end plate 18b, a cooling medium such as pure water, ethylene glycol, or oil is supplied from the inlet pipe section 90a of the cooling medium supply manifold 72a to the internal space 72ac. The cooling medium is distributed to each of the two cooling medium supply communication holes 50a communicating with the upper and lower sides of the internal space 72ac.

  Therefore, as shown in FIG. 3, the oxidant gas is introduced into the oxidant gas flow path 58 of the first metal separator 42 from the oxidant gas supply communication hole 46a. The oxidant gas moves in the direction of arrow A along the oxidant gas flow path 58 and is supplied to the cathode electrode 54 of the electrolyte membrane / electrode structure 40.

  On the other hand, the fuel gas is supplied to the fuel gas channel 60 of the second metal separator 44 from the fuel gas supply communication hole 48a. The fuel gas moves in the direction of arrow A along the fuel gas flow path 60 and is supplied to the anode electrode 56 of the electrolyte membrane / electrode structure 40.

  Therefore, in the electrolyte membrane / electrode structure 40, the oxidizing gas supplied to the cathode electrode 54 and the fuel gas supplied to the anode electrode 56 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is called.

  Next, the oxidant gas consumed by being supplied to the cathode electrode 54 of the electrolyte membrane / electrode structure 40 is discharged in the direction of arrow B along the oxidant gas discharge communication hole 46b. On the other hand, the fuel gas supplied to and consumed by the anode electrode 56 of the electrolyte membrane / electrode structure 40 is discharged in the direction of arrow B along the fuel gas discharge communication hole 48b.

  Further, the cooling medium supplied to the two upper and lower cooling medium supply communication holes 50 a is introduced into the cooling medium flow path 62 between the first metal separator 42 and the second metal separator 44 adjacent to each other. The cooling medium once flows along the inward direction of the arrow C in directions close to each other from the two upper and lower cooling medium supply communication holes 50a, and then moves in the direction of the arrow A to cool the electrolyte membrane / electrode structure 40. To do. The cooling medium moves in the direction away from each other in the direction of arrow C, and is then discharged in the direction of arrow B along the two upper and lower cooling medium discharge communication holes 50b.

  As shown in FIGS. 1 and 4, the cooling medium is discharged from the two upper and lower cooling medium discharge communication holes 50b into the internal space 72bc of the cooling medium discharge manifold 72b. The cooling medium flows to the center side of the internal space 72bc, and then is discharged to the outside from the outlet pipe portion 90b.

  In this case, in the present embodiment, as shown in FIG. 4, an upper wall surface 98a constituting the ceiling portion is provided at an angle α2 ° with respect to the horizontal direction ho in the internal space 72ac of the cooling medium supply manifold 72a. Yes. For this reason, the air introduced into the internal space 72ac of the cooling medium supply manifold 72a flows to the uppermost position side of the upper wall surface 98a along the inclination of the upper wall surface 98a.

  At that time, a first air vent hole 100a is formed in the cooling medium supply manifold 72a adjacent to the uppermost position of the upper wall surface 98a. Therefore, the air that has flowed to the uppermost position along the inclination of the upper wall surface 98a is discharged from the first air vent hole 100a to the outside of the cooling medium supply manifold 72a. The first air vent hole 100a is disposed at a position farthest from the inlet duct 90a on the upper wall surface 98a.

  This makes it possible to reliably suppress air from staying in the internal space 72ac of the cooling medium supply manifold 72a with a simple and economical configuration. For this reason, a cooling medium can distribute | circulate smoothly and equally with respect to the two cooling medium supply communicating holes 50a, respectively. Therefore, the effect that the cooling performance of each fuel cell 12 is improved is obtained.

  On the other hand, in the internal space 72bc of the cooling medium discharge manifold 72b, an upper wall surface 98b constituting the ceiling portion is provided so as to be inclined by an angle α3 ° from the horizontal direction ho. For this reason, the air introduced into the internal space 72bc of the cooling medium discharge manifold 72b flows along the inclination of the upper wall surface 98b to the uppermost position side of the upper wall surface 98b.

  At that time, a second air vent hole 100b is formed in the cooling medium discharge manifold 72b adjacent to the uppermost position of the upper wall surface 98b. The second air vent hole portion 100b is disposed at a position farthest from the outlet conduit portion 90b on the upper wall surface 98b. Accordingly, the air that has flowed to the uppermost position along the inclination of the upper wall surface 98b is discharged from the second air vent hole 100b to the outside of the cooling medium discharge manifold 72b.

  Accordingly, it is possible to reliably suppress air from staying in the internal space 72bc of the cooling medium discharge manifold 72b with a simple and economical configuration. For this reason, the cooling medium can smoothly and evenly flow from the two cooling medium discharge communication holes 50b on the upper and lower sides to the cooling medium discharge manifold 72b. Therefore, the effect that the cooling performance of each fuel cell 12 is improved is obtained.

  In the present embodiment, the two cooling medium supply communication holes 50a are provided on the top and the bottom, and the two cooling medium discharge communication holes 50b are provided on the top and the bottom. However, the present invention is not limited to this. For example, one cooling medium supply communication hole 50a may be provided above and below, and one cooling medium discharge communication hole 50b may be provided above and below.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 12 ... Fuel cell 12as ... Laminated body 18a, 18b ... End plate 26 ... Casing 40 ... Electrolyte membrane electrode structure 42, 44 ... Metal separator 46a ... Oxidant gas supply communication hole 46b ... Oxidant gas discharge Communication hole 48a ... Fuel gas supply communication hole 48b ... Fuel gas discharge communication hole 50a ... Cooling medium supply communication hole 50b ... Cooling medium discharge communication hole 52 ... Solid polymer electrolyte membrane 54 ... Cathode electrode 56 ... Anode electrode 58 ... Oxidant gas Flow path 60 ... Fuel gas flow path 62 ... Cooling medium flow path 68a ... Oxidant gas supply manifold 68b ... Oxidant gas discharge manifold 70a ... Fuel gas supply manifold 70b ... Fuel gas discharge manifold 72a ... Cooling medium supply manifold 72b ... Cooling medium Discharge manifold 72ac, 72bc ... internal space 74a, 74b ... Insulating plate 76a ... Cooling medium inlet 90a ... Inlet pipe part 90b ... Outlet pipe part 98a, 98b ... Upper wall surface 100a, 100b ... Air vent hole part

Claims (4)

An electrolyte membrane / electrode structure in which electrodes are provided on both sides of the electrolyte membrane and a separator are stacked in a horizontal direction, and a plurality of the fuel cells are stacked in a horizontal direction, and end plates are provided at both ends in the stacking direction. Between the separators adjacent to each other, a cooling medium flow path for flowing a cooling medium along the separator surface is formed, and the cooling medium flow path is formed on the inlet side of the cooling medium flow path. A pair of upper and lower cooling medium supply communication holes are provided across the flow path width direction, and a pair of upper and lower cooling medium sandwiches the cooling medium flow path in the flow path width direction on the outlet side of the cooling medium flow path. A fuel cell stack provided with a medium discharge communication hole,
One end plate is provided with a cooling medium manifold communicating with the pair of upper and lower cooling medium supply communication holes or the pair of upper and lower cooling medium discharge communication holes,
A fuel cell characterized in that an upper wall surface constituting a ceiling portion is inclined from a horizontal direction inside the cooling medium manifold, and an air vent hole is formed adjacent to the uppermost position of the upper wall surface. stack. 2. The fuel cell stack according to claim 1, wherein the cooling medium manifold includes a cooling medium supply manifold that communicates with the pair of upper and lower cooling medium supply communication holes, and a cooling medium discharge manifold that communicates with the pair of upper and lower cooling medium discharge communication holes. And
The fuel cell stack, wherein the upper wall surface provided in the cooling medium supply manifold and the upper wall surface provided in the cooling medium discharge manifold are inclined upward in a direction away from each other. . 3. The fuel cell stack according to claim 2, wherein the cooling medium supply manifold is provided with a cooling medium inlet pipe located at a central portion in the flow path width direction on a side portion close to the cooling medium discharge manifold. on the other hand,
The fuel cell stack according to claim 1, wherein the cooling medium discharge manifold is provided with a cooling medium outlet pipe at a central portion in the flow path width direction on a side portion spaced apart from the cooling medium supply manifold.   4. The fuel cell stack according to claim 3, wherein the cooling medium inlet conduit is inclined downward with respect to a cooling medium flow direction of the cooling medium flow path.

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