JP5810068B2 - Fuel cell stack - Google Patents

Description

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

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) in which an anode electrode and a cathode electrode are disposed on both sides of an electrolyte membrane made of a polymer ion exchange membrane is sandwiched by a pair of separators. A unit cell is provided. This type of fuel cell is normally used as an in-vehicle fuel cell stack by stacking a predetermined number of unit cells.

  In the fuel cell described above, a fuel gas flow path is provided in the surface of one separator so as to flow the fuel gas so as to face the anode electrode, and oxidation is performed in the surface of the other separator so as to face the cathode electrode. An oxidant gas flow path for flowing the agent gas is provided. Furthermore, between each separator which comprises each fuel cell and adjoins mutually, the cooling medium flow path for flowing a cooling medium in the electrode range is formed along the separator surface.

  Further, in this type of fuel cell, the fuel gas inlet communication hole and the fuel gas outlet communication hole for flowing the fuel gas through the unit cell in the stacking direction, and the oxidant gas inlet communication hole for flowing the oxidant gas In many cases, a so-called internal manifold type fuel cell is provided which includes an oxidant gas outlet communication hole, a cooling medium inlet communication hole for flowing a cooling medium, and a cooling medium outlet communication hole.

  For example, a fuel cell stack disclosed in Patent Document 1 includes an electrolyte / electrode structure in which a pair of electrodes are provided on both sides of an electrolyte and a metal separator having a rectangular plane, and the electrode of the metal separator. The opposing surface includes a power generation unit provided with a corrugated gas flow path for supplying a reaction gas that is a fuel gas or an oxidant gas along the electrode, and the back surface of the corrugated gas flow path is provided between the power generation units. The power generation units are stacked on each other so as to form a cooling medium flow path having a shape.

  The two opposite sides of the metal separator are provided with a reaction gas inlet communication hole and a reaction gas outlet communication hole through which the reaction gas flows through in the stacking direction. A pair of cooling medium inlets that penetrate in the stacking direction and are close to at least the reaction gas inlet communication hole or the reaction gas outlet communication hole, and are distributed to the respective sides to flow the cooling medium. A communication hole and a pair of cooling medium outlet communication holes are provided.

  Accordingly, since the pair of cooling medium inlet communication holes and the pair of cooling medium outlet communication holes are provided separately, the cooling medium can be uniformly and reliably supplied to the entire cooling medium flow path.

International Publication No. 2010/082589 Pamphlet

  By the way, in the fuel cell described above, the cooling medium inlet communication hole and the cooling medium flow path are actually communicated via a plurality of connecting flow paths, and at the inlet side of the cooling medium flow path, In many cases, a buffer portion is provided between the pair of cooling medium inlet communication holes.

  For this reason, the cooling medium is supplied from the cooling medium inlet communication hole to the cooling medium flow path (power generation section) through the connection flow path, and is also supplied to the central portion of the power generation section by bypassing to the buffer section. ing.

  By the way, the buffer portion is configured in an asymmetric shape due to, for example, the opening shape of the reaction gas inlet communication hole and the reaction gas outlet communication hole, and the position and shape of other components such as a reinforcing member and a positioning member. easy. For example, an asymmetric triangular buffer unit is used. Therefore, since the width shape of the buffer part is asymmetrical along the width direction of the cooling medium flow path, the cooling medium supplied to the buffer part from each of the pair of cooling medium inlet communication holes causes the buffer part to be uneven. Easy to distribute. As a result, the temperature in the power generation unit becomes non-uniform, and local deterioration or stagnant water may occur.

  The present invention solves this type of problem, and with a simple configuration, the cooling medium can be supplied uniformly over the entire surface of the power generation unit. An object of the present invention is to provide a fuel cell stack that can be suppressed as much as possible.

  The present invention includes a fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a separator are stacked, and a plurality of the fuel cells are stacked and the separators adjacent to each other In the meantime, a cooling medium flow path for circulating the cooling medium along the separator surface is formed, and buffer portions are respectively provided on the inlet side of the cooling medium flow path and the outlet side of the cooling medium flow path, On the inlet side of the cooling medium flow path, a pair of cooling medium inlet communication holes are provided on both sides in the flow path width direction with the buffer portion interposed therebetween, and on the outlet side of the cooling medium flow path, The present invention relates to a fuel cell stack in which a pair of cooling medium outlet communication holes are provided on both sides in the road width direction with the buffer portion interposed therebetween.

In this fuel cell stack, the buffer portion is configured in an asymmetrical triangle having a vertex at a position spaced from the center in the flow path width direction of the cooling medium flow path to one side in the flow path width direction, and a pair of cooling medium inlet communication holes And the buffer portion on the inlet side are communicated with each other through a connection channel, and the pair of cooling medium outlet communication holes and the buffer portion on the outlet side are communicated with each other through a connection channel. And at least the buffer section on the inlet side or the buffer section on the outlet side has the number of flow paths of the connection flow path on the side where the apex of the buffer section is close to the connection flow path on the side where the apex of the buffer section is separated The number is set to be smaller than the number of flow paths.

  Further, in this fuel cell stack, an oxidant gas communication hole that allows the oxidant gas to flow in the stacking direction of the fuel cell in the vicinity of the buffer portion and a fuel gas communication hole that allows the fuel gas to flow in the stacking direction flow. And the opening area of the oxidant gas communication hole is set larger than the opening area of the fuel gas communication hole, and the apex position of the buffer portion is the center in the flow path width direction. It is preferable that it is spaced apart from the fuel gas communication hole side.

  According to the present invention, each of the connection flow paths constituting the pair of communication holes is set to have a different number of flow paths corresponding to the asymmetric triangular buffer portion. For this reason, in the buffer part, it is possible to supply a larger amount of the cooling medium to the part where the cooling medium is difficult to flow than other parts, and to supply the cooling medium evenly to the entire cooling medium flow path. become.

  Thereby, with a simple configuration, the cooling medium can be supplied uniformly over the entire surface of the power generation unit, and local deterioration due to temperature nonuniformity and generation of stagnant water can be suppressed as much as possible.

1 is an exploded perspective view of a main part of a fuel cell constituting a fuel cell stack according to a first embodiment of the present invention. FIG. 2 is a sectional view of the fuel cell taken along line II-II in FIG. 1. It is explanatory drawing of one surface of the anode side separator which comprises the said fuel cell. It is explanatory drawing of the other surface of the said anode side separator. It is comparison explanatory drawing of the flow volume of the cooling medium supplied to a cooling medium flow path in the example of this application, and a prior art example. It is principal part explanatory drawing of the cooling-medium entrance communication hole which comprises the said fuel cell. It is front explanatory drawing of the anode side separator which comprises the fuel cell stack which concerns on the 2nd Embodiment of this invention.

  As shown in FIGS. 1 and 2, the fuel cell stack 10 according to the first embodiment of the present invention includes a plurality of fuel cells 11 in the standing direction (the electrode surface is parallel to the vertical direction) in the arrow A direction. Laminated. The fuel cell 11 includes an electrolyte membrane / electrode structure 12, and a cathode side separator 14 and an anode side separator 16 that sandwich the electrolyte membrane / electrode structure 12.

  The cathode side separator 14 and the anode side separator 16 are made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a thin plate-like metal separator whose surface is subjected to anticorrosion treatment. The metal separator has a rectangular planar shape, and is formed into a concavo-convex shape by pressing into a wave shape. The cathode side separator 14 and the anode side separator 16 may be constituted by, for example, a carbon separator instead of the metal separator.

  The cathode-side separator 14 and the anode-side separator 16 have a horizontally long shape, and the short sides are directed in the direction of gravity (arrow C direction) and the long sides are directed in the horizontal direction (arrow B direction) (horizontal stacking). Composed. In addition, you may comprise so that a short side may face a horizontal direction and a long side may go to a gravitational direction, and you may comprise so that a separator surface may face a horizontal direction (stacking of a perpendicular direction).

  An oxidant gas inlet communication hole 18a for supplying an oxidant gas, for example, an oxygen-containing gas, communicates with each other in the arrow A direction at one end edge of the long side direction (arrow B direction) of the fuel cell 11. A fuel gas outlet communication hole 20b for discharging a fuel gas, for example, a hydrogen-containing gas, is provided. The oxidant gas inlet communication hole 18a and the fuel gas outlet communication hole 20b have a substantially triangular shape, and the oxidant gas inlet communication hole 18a is set to have a larger opening area than the fuel gas outlet communication hole 20b.

  The other end edge in the long side direction of the fuel cell 11 communicates with each other in the direction of arrow A, and a fuel gas inlet communication hole 20a for supplying fuel gas, and an oxidant gas for discharging oxidant gas. An outlet communication hole 18b is provided. The oxidant gas outlet communication hole 18b and the fuel gas inlet communication hole 20a have a substantially triangular shape, and the oxidant gas outlet communication hole 18b is set to have a larger opening area than the fuel gas inlet communication hole 20a.

  Two cooling medium inlet communication holes 22 a for communicating with each other in the direction of arrow A and for supplying a cooling medium are provided at one end of both ends in the short side direction (arrow C direction) of the fuel cell 11. Two cooling medium outlet communication holes 22b for discharging the cooling medium are provided on the other end of both ends in the short side direction of the fuel cell 11.

  The cooling medium inlet communication hole 22 a has an opening shape that is long and rectangular along the flow direction of the cooling medium flow path 38 (arrow B direction). The cooling medium inlet communication hole 22a is provided with a rib portion 22a (rib) that divides the rectangular shape into a first region 22a1 and a second region 22a2 at an intermediate portion in the longitudinal direction of the rectangular shape. The rib portion 22a (rib) may be provided as necessary, and may be unnecessary.

  The cooling medium outlet communication hole 22 b is set to have a rectangular shape whose opening shape is long along the flow direction (arrow B direction) of the cooling medium flow path 38. The cooling medium outlet communication hole 22b is provided with a rib portion 22b (rib) that divides the rectangular shape into a first region 22b1 and a second region 22b2 at a rectangular intermediate portion in the longitudinal direction. The rib portion 22b (rib) may be provided as necessary, and may be unnecessary.

  The electrolyte membrane / electrode structure 12 includes, for example, a fluorine-based or hydrocarbon-based solid polymer electrolyte membrane 24, and a cathode electrode 26 and an anode electrode 28 that sandwich the solid polymer electrolyte membrane 24.

  The cathode electrode 26 and the anode electrode 28 are formed by uniformly applying a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface thereof to the surface of the gas diffusion layer. And an electrode catalyst layer (not shown) to be formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 24.

  As shown in FIG. 1, an oxidant gas flow path that connects an oxidant gas inlet communication hole 18 a and an oxidant gas outlet communication hole 18 b to the surface 14 a of the cathode separator 14 facing the electrolyte membrane / electrode structure 12. 30 is formed. An inlet buffer portion 32a and an outlet buffer portion 32b each having a plurality of embosses are provided in the vicinity of the inlet and the outlet of the oxidizing gas channel 30.

  The inlet buffer portion 32a has a substantially triangular shape along the shapes of the oxidant gas inlet communication hole 18a and the fuel gas outlet communication hole 20b, and the apex position is spaced downward from the center in the height direction (arrow C direction). Is set. The inlet buffer portion 32a has a length of one side and a length of the other side different from each other with the flow path width direction as a base. The outlet buffer portion 32b has a substantially triangular shape along the shapes of the fuel gas inlet communication hole 20a and the oxidant gas outlet communication hole 18b, and the apex position is spaced upward from the center in the height direction (arrow C direction). Is set.

  As shown in FIG. 3, a fuel gas flow path 34 that connects the fuel gas inlet communication hole 20 a and the fuel gas outlet communication hole 20 b is formed on the surface 16 a of the anode separator 16 that faces the electrolyte membrane / electrode structure 12. Is done. In the vicinity of the inlet and the outlet of the fuel gas flow path 34, an inlet buffer portion 36a and an outlet buffer portion 36b each having a plurality of embosses are provided.

  The inlet buffer portion 36a has a substantially triangular shape along the shapes of the fuel gas inlet communication hole 20a and the oxidant gas outlet communication hole 18b, and the vertex position in the horizontal direction is set apart from the center in the height direction upward. The The outlet buffer portion 36b has an asymmetric triangle along the shapes of the oxidant gas inlet communication hole 18a and the fuel gas outlet communication hole 20b, and the apex position is set to be spaced downward from the center in the height direction (arrow C direction). Is done.

  Between the surface 16b of the anode-side separator 16 and the surface 14b of the cathode-side separator 14, a cooling medium flow path 38 communicating with the cooling medium inlet communication holes 22a, 22a and the cooling medium outlet communication holes 22b, 22b is formed. (See FIGS. 1 and 4). The cooling medium flow path 38 circulates the cooling medium over the electrode range of the electrolyte membrane / electrode structure 12, and the inlet buffer section 40a and the outlet buffer are provided in the vicinity of the inlet and the outlet of the cooling medium flow path 38, respectively. A portion 40b is provided.

  In the anode-side separator 16, the cooling medium flow path 38 has a back surface shape of the fuel gas flow path 34, and the inlet buffer portion 40a and the outlet buffer portion 40b have the back surface shapes of the outlet buffer portion 36b and the inlet buffer portion 36a. It is formed. In the cathode-side separator 14, the cooling medium flow path 38 has a back surface shape of the oxidant gas flow path 30, and the inlet buffer portion 40a and the outlet buffer portion 40b have back surface shapes of the inlet buffer portion 32a and the outlet buffer portion 32b. Formed as. Hereinafter, description will be given using the anode-side separator 16.

  As shown in FIG. 4, the inlet buffer section 40a has an asymmetrical triangle along the shapes of the oxidant gas inlet communication hole 18a and the fuel gas outlet communication hole 20b, and the position of the vertex 40ae is in the height direction (flow path). The width direction is set with a distance h1 downward from the center (arrow C direction). The outlet buffer section 40b has an asymmetrical triangle along the shapes of the fuel gas inlet communication hole 20a and the oxidant gas outlet communication hole 18b, and the position of the apex 40be is the center in the height direction (channel width direction) (arrow C). The distance h2 is set upward from the direction).

  A first seal member 42 is integrally formed on the surfaces 14 a and 14 b of the cathode side separator 14 around the outer peripheral edge of the cathode side separator 14. A second seal member 44 is integrally formed on the surfaces 16 a and 16 b of the anode separator 16 so as to go around the outer peripheral edge of the anode separator 16. As the first seal member 42 and the second seal member 44, for example, EPDM, NBR, fluororubber, 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.

  A first seal member 42 is notched on the surface 14a of the cathode side separator 14, and a plurality of inlet connection channels 46a communicating the inlet buffer portion 32a and the oxidant gas inlet communication hole 18a, and the outlet buffer portion 32b. A plurality of outlet connection flow paths 46b are formed to communicate with the oxidant gas outlet communication hole 18b. As shown in FIG. 3, the second seal member 44 is notched on the surface 16a of the anode side separator 16, and a plurality of inlet connection channels 48a communicating the inlet buffer portion 36a and the fuel gas inlet communication hole 20a. And a plurality of outlet connection channels 48b communicating with the outlet buffer portion 36b and the fuel gas outlet communication hole 20b.

  As shown in FIG. 4, on the surface 16b of the anode side separator 16, the second seal member 44 is notched, and inlet connection flow paths 50au1 and 50au2 are formed in the vicinity of the upper side coolant supply passage 22a. The inlet connection flow paths 50ad1 and 50ad2 are formed in the vicinity of the cooling medium inlet communication hole 22a on the lower side. The inlet connection channels 50au1 and 50au2 may be formed integrally with the second seal member 44, or may be formed by the anode side separator 16 itself.

  The inlet connection flow path 50au1 communicates the upper cooling medium inlet communication hole 22a and the inlet buffer section 40a, while the inlet connection flow path 50ad1 includes the lower cooling medium inlet communication hole 22a and the inlet buffer section 40a. Communicate. The inlet connection channel 50au1 and the inlet connection channel 50ad1 are set to have different numbers of channels. In the first embodiment, the inlet connection channel 50au1 includes, for example, four inlet connection channels 50ad1. Are set to two, for example.

  It is preferable that the inlet connection channel 50au1 and the inlet connection channel 50ad1 have the same channel cross-sectional area and are set at an equal pitch. The number of flow paths can be variously changed according to the shape of the inlet buffer section 40a, and at least the number of flow paths of the inlet connection flow path 50au1 may be set larger than the number of flow paths of the inlet connection flow path 50ad1. .

  The inlet connection flow path 50au2 communicates the cooling medium inlet communication hole 22a and the cooling medium flow path 38 on the upper side. The inlet connection flow path 50ad2 communicates the cooling medium inlet communication hole 22a on the lower side with the cooling medium flow path 38.

  The surface 16b of the anode-side separator 16 is notched with a second seal member 44, and a plurality of outlet connection flow paths 50bu1, 50bu2, which communicate the upper cooling medium outlet communication hole 22b and the outlet buffer portion 40b, and A plurality of outlet connection channels 50bd1 and 50bd2 are formed to communicate the cooling medium outlet communication hole 22b on the lower side and the outlet buffer portion 40b.

  The outlet connection flow path 50bu1 communicates the upper cooling medium outlet communication hole 22b and the outlet buffer part 40b, while the outlet connection flow path 50bd1 connects the lower cooling medium outlet communication hole 22b and the outlet buffer part 40b. Communicate. The outlet connection channel 50bu1 and the outlet connection channel 50bd1 are set to different numbers of channels, and in the first embodiment, the outlet connection channel 50bu1 is two and the outlet connection channel 50bd1 is four. , Respectively.

  It is preferable that the outlet connection channel 50bu1 and the outlet connection channel 50bd1 have the same channel cross-sectional area and are set at an equal pitch. The inlet connection channel 50au1 and the outlet connection channel 50bd1 are preferably set to the same number of channels, and the inlet connection channel 50ad1 and the outlet connection channel 50bu1 are preferably set to the same number of channels.

  The outlet connection channel 50bu1 and the outlet connection channel 50bd1 may be set to the same number of channels. In addition, the outlet connection channel 50bu1 and the outlet connection channel 50bd1 are set to different numbers of channels, while the inlet connection channel 50au1 and the inlet connection channel 50ad1 are set to the same number of channels. Good.

  The outlet connection flow path 50bu2 communicates the cooling medium outlet communication hole 22b on the upper side with the cooling medium flow path 38. The outlet connection flow path 50bd2 communicates the cooling medium outlet communication hole 22b on the lower side with the cooling medium flow path 38.

  The operation of the fuel cell 11 configured as described above will be described below.

  First, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 18a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 20a. Supplied. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the pair of cooling medium inlet communication holes 22a.

  For this reason, the oxidant gas is introduced into the oxidant gas flow path 30 of the cathode side separator 14 from the oxidant gas inlet communication hole 18a. The oxidant gas moves in the arrow B direction (horizontal direction) along the oxidant gas flow path 30 and is supplied to the cathode electrode 26 of the electrolyte membrane / electrode structure 12.

  On the other hand, the fuel gas is supplied to the fuel gas flow path 34 of the anode-side separator 16 from the fuel gas inlet communication hole 20a. As shown in FIG. 3, the fuel gas moves in the horizontal direction (arrow B direction) along the fuel gas flow path 34 and is supplied to the anode electrode 28 of the electrolyte membrane / electrode structure 12 (see FIG. 1). .

  Therefore, in the electrolyte membrane / electrode structure 12, the oxidant gas supplied to the cathode electrode 26 and the fuel gas supplied to the anode electrode 28 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 26 of the electrolyte membrane / electrode structure 12 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 18b. On the other hand, the fuel gas supplied to and consumed by the anode electrode 28 of the electrolyte membrane / electrode structure 12 is discharged in the direction of arrow A along the fuel gas outlet communication hole 20b.

  The cooling medium supplied to the pair of cooling medium inlet communication holes 22 a is introduced into the cooling medium flow path 38 between the cathode side separator 14 and the anode side separator 16. As shown in FIGS. 1 and 4, the cooling medium once flows along the inside of the arrow C direction (gravity direction) and then moves in the arrow B direction (horizontal direction) to move the electrolyte membrane / electrode structure 12. Cooling. This cooling medium moves outward in the direction of arrow C, and is then discharged to the pair of cooling medium outlet communication holes 22b.

  In this case, in the first embodiment, each of the inlet connection channels 50au1 and 50ad1 is set to have a different number of channels corresponding to the asymmetric triangular inlet buffer unit 40a. For this reason, in the inlet buffer part 40a, the cooling medium can be supplied in a larger amount to the part where the cooling medium is difficult to flow than other parts, and the cooling medium is supplied uniformly to the entire cooling medium flow path 38. It becomes possible.

  Specifically, in the entrance buffer unit 40a, the position of the vertex 40ae is set so as to be separated from the center in the height direction by a distance h1. The upper inlet connection channel 50au1 is set to four, and the lower inlet connection channel 50ad1 is set to two.

  Here, the structure (conventional example) in which the inlet connection channel 50au1 and the inlet connection channel 50ad1 are set to the same number of channels, the inlet connection channel 50au1 is four, and the inlet connection flow The distribution state of the cooling medium supplied to the cooling medium flow path 38 was compared using a structure (example of the present application) in which two paths 50ad1 are set.

  As a result, as shown in FIG. 5, in the structure of the conventional example, a large amount of cooling medium is supplied to the upper side of the cooling medium flow path 38, and a small amount of the cooling medium flows to the lower side of the cooling medium flow path 38. A cooling medium is supplied. Since the inlet buffer 40a is an asymmetric triangle in which the position of the vertex 40ae in the horizontal direction is offset downward, the width dimension on the lower side (dimension in the direction of arrow B) is widened and supplied below the inlet buffer 40a. This is because the cooling medium to be flowed easily flows to the upper side of the inlet buffer 40a.

  For this reason, the flow rate of the cooling medium supplied along the width direction of the cooling medium flow path 38 is different, and a large temperature difference is likely to occur in the width direction in the cooling medium flow path 38. Therefore, there exists a problem that durability and electric power generation stability fall.

  On the other hand, in the example of the present application, the number of flow paths of the lower inlet connection flow path 50ad1 is set to be smaller than the number of flow paths of the upper inlet connection flow path 50ad1. Thereby, as shown in FIG. 6, the flow rate of the cooling medium supplied from the inlet connection channel 50au1 becomes larger than the flow rate of the cooling medium supplied from the inlet connection channel 50ad1.

  That is, in the conventional example, the stagnation of the cooling medium occurs in the vicinity of the vertex 40ae of the inlet buffer section 40a in FIG. 6, whereas in the present example, the flow path between the inlet connection flow path 50au1 and the inlet connection flow path 50ad1. By changing the number, the stagnation in the vicinity of the vertex 40ae was eliminated. For this reason, as shown in FIG. 5, the cooling medium can be supplied uniformly along the width direction of the cooling medium flow path 38.

  Therefore, it is possible to supply the cooling medium over the entire surface of the power generation unit with a simple configuration, and it is possible to suppress the local deterioration due to the uneven temperature and the generation of stagnant water as much as possible. It is done.

  The cooling medium outlet communication hole 22b side is configured in the same manner as the cooling medium inlet communication hole 22a, and the same effect can be obtained.

  Further, in the first embodiment, a fuel constituted by a single electrolyte membrane / electrode structure 12, that is, a single MEA, and a cathode separator 14 and an anode separator 16, that is, two separators. Although the battery 11 is used, it is not limited to this. For example, a unit cell including two MEAs and three separators (MEA interposed between separators) may be provided, and the present invention may be applied to a cooling medium fluid configured between the unit cells.

  FIG. 7 is an explanatory front view of the anode-side separator 60 constituting the fuel cell stack according to the second embodiment of the present invention. Note that the same components as those of the anode separator 16 constituting the fuel cell stack 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  On the surface 60a of the anode separator 60 where the cooling medium flow path 38 is formed, each cooling medium inlet communication hole 22a is set in a rectangular shape elongated in the direction of arrow B. The cooling medium inlet communication hole 22a is provided with an inclined portion 22ar on the end side close to the inlet buffer portion 40a.

  In the vicinity of the upper coolant supply passage 22a, an inlet connection channel 50au1 is formed along the inclined portion 22ar. In the vicinity of the cooling medium inlet communication hole 22a on the lower side, an inlet connection flow path 50ad1 is formed along the inclined portion 22ar.

  On the surface 60a of the anode-side separator 60 where the cooling medium flow path 38 is formed, each cooling medium outlet communication hole 22b is set in a rectangular shape elongated in the direction of arrow B, and is on the end side close to the outlet buffer section 40b. Is provided with an inclined portion 22br. In the vicinity of the cooling medium outlet communication hole 22b on the upper side, an outlet connection flow path 50bu1 is formed along the inclined portion 22br. In the vicinity of the cooling medium outlet communication hole 22b on the lower side, an outlet connection channel 50bd1 is formed along the inclined portion 22br.

  In the second embodiment configured as described above, the inlet connection flow paths 50au1 and 50ad1 are set to have different numbers of flow paths corresponding to the asymmetric triangular inlet buffer section 40a. For this reason, the same effects as those in the first embodiment can be obtained, for example, the cooling medium can be uniformly supplied to the entire cooling medium flow path 38.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 11 ... Fuel cell 12 ... Electrolyte membrane and electrode structure 14 ... Cathode side separator 16, 60 ... Anode side separator 18a ... Oxidant gas inlet communication hole 18b ... Oxidant gas outlet communication hole 20a ... Fuel gas inlet Communication hole 20b ... Fuel gas outlet communication hole 22a ... Cooling medium inlet communication hole 22a1, 22a2, 22b1, 22b2 ... Regions 22a (rib), 22b (rib) ... Rib portions 22ar, 22br ... Inclined portions 22b ... Cooling medium outlet communication holes DESCRIPTION OF SYMBOLS 24 ... Solid polymer electrolyte membrane 26 ... Cathode electrode 28 ... Anode electrode 30 ... Oxidant gas flow path 32a, 36a, 40a ... Inlet buffer part 32b, 36b, 40b ... Outlet buffer part 34 ... Fuel gas flow path 38 ... Cooling medium Flow path 40ae, 40be ... vertex 50ad1, 50ad2, 50au1, 50au2 ... inlet connection flow path 0bd1,50bd2,50bu1,50bu2 ... outlet connection channel

Claims (2)

A fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a separator are stacked, and a plurality of the fuel cells are stacked, and between the separators adjacent to each other, A cooling medium flow path for circulating the cooling medium along the separator surface is formed, and a buffer portion is provided on each of the inlet side of the cooling medium flow path and the outlet side of the cooling medium flow path. On the inlet side of the passage, a pair of cooling medium inlet communication holes are provided on both sides in the flow path width direction with the buffer portion interposed therebetween, and on the outlet side of the cooling medium flow path, A fuel cell stack in which a pair of cooling medium outlet communication holes are provided on both sides of the buffer portion,
The buffer section is configured in an asymmetric triangle having a vertex at a position spaced apart from the center in the flow path width direction of the cooling medium flow path to one of the flow path width directions,
The pair of cooling medium inlet communication holes and the buffer portion on the inlet side communicate with each other through a connection channel,
The pair of cooling medium outlet communication holes and the buffer part on the outlet side communicate with each other through a connection channel,
At least the buffer unit or the outlet side of the buffer unit of the inlet side, the flow path number of the connecting channel on the side where the apex of the buffer portion is proximate is the connection of the side of the apex of the buffer portion is separated A fuel cell stack characterized in that the number of channels is set to be smaller than the number of channels . The fuel cell stack according to claim 1 Symbol placement, and oxygen-containing gas hole for flowing oxidant gas in proximity to the buffer unit in the stacking direction of the fuel cell, the fuel gas communication circulating the fuel gas in the stacking direction A hole is provided along the flow path width direction,
The opening area of the oxidant gas communication hole is set larger than the opening area of the fuel gas communication hole, and the apex position of the buffer portion is spaced from the center in the flow path width direction to the fuel gas communication hole side. A fuel cell stack characterized by being provided.

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