JP2014127301A - Fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To evenly supply a cooling medium over the whole area of a power generation part, with a simple configuration, thereby suppressing local deterioration and generation of retention water due to non-uniformity of temperature as much as possible.SOLUTION: In a fuel cell stack 10, a cooling medium passage 38 is formed between a cathode side separator 14 and an anode side separator 16. A pair of cooling medium inlet communication holes 22a are provided so as to sandwich an inlet buffer part 40a therebetween in a width direction, on the inlet side of the cooling medium passage 38. Each of the cooling medium inlet communication holes 22a has a rectangular shape and is provided with a tilted part 41a of which an opening cross section area decreases toward the direction approaching the inlet buffer part 40a.

Description

  The present invention relates to a fuel cell stack having 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, and a plurality of the fuel cells are stacked.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure in which an anode electrode is provided on one side of an electrolyte membrane made of a polymer ion exchange membrane and a cathode electrode is provided on the other side of the electrolyte membrane ( MEA) is provided with a unit cell sandwiched by a pair of separators. 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 metal separator. The electrode facing 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 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 back surface 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 to the cooling medium flow path from the cooling medium inlet communication hole to the cooling medium flow path, that is, to the power generation section (electrode section), and bypassed to the buffer section, thereby the power generation section It is supplied to the central part. However, since the cooling medium tends to flow through the shortest flow path, there is a possibility that the cooling medium cannot be sufficiently supplied to the central portion of the power generation unit.

  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 capable of suppressing generation as much as possible.

  The present invention has 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, and a plurality of the fuel cells are stacked and adjacent to each other. Between the separators, there is formed a cooling medium flow path through which the cooling medium flows along the separator surface, 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. A pair of cooling medium inlet communication holes are provided on both sides in the flow path width direction on the inlet side of the cooling medium flow path, 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 flow path width direction with the buffer portion interposed therebetween.

  In this fuel cell stack, at least the cooling medium inlet communication hole has an opening shape that is set to be a long rectangular shape along the flow direction of the cooling medium flow path, and has an opening cross-sectional area in a direction close to the buffer portion. Is provided with an inclined portion.

  In this fuel cell stack, at least the cooling medium inlet communication hole and the buffer portion communicate with each other through a plurality of connection channels, and the plurality of connection channels are set to have the same channel length. Is preferred.

  Furthermore, in this fuel cell stack, it is preferable that the plurality of connection channels are inclined in the buffer portion side with respect to the flow direction of the cooling medium channel and are arranged in parallel to each other.

  According to the present invention, at least the cooling medium inlet communication hole is provided with the inclined portion whose opening cross-sectional area becomes smaller in the direction close to the buffer portion. For this reason, a cooling medium is derived | led-out toward the center side of a buffer part from an inclination part. Therefore, the cooling medium can be reliably supplied to the buffer part not only on the both ends in the width direction adjacent to the pair of cooling medium inlet communication holes but also on the center part in the width direction. As a result, the cooling medium can be satisfactorily supplied to the entire buffer unit, and the cooling medium can be evenly supplied to the entire cooling medium flow path.

  For this reason, it becomes possible to supply the cooling medium evenly over the entire surface of the power generation unit with a simple configuration, and to suppress as much as possible local degradation of MEA and generation of stagnant water due to uneven temperature. it can.

It is a principal part disassembled perspective explanatory drawing of the fuel cell which comprises the fuel cell stack which concerns on embodiment of this 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.

  As shown in FIGS. 1 and 2, in the fuel cell stack 10 according to the embodiment of the present invention, a plurality of fuel cells 11 are stacked in the direction of arrow A with the standing posture (the electrode surface is parallel to the vertical direction). . 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 rectangular 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 rectangular 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. Details of the cooling medium inlet communication hole 22a and the cooling medium outlet communication hole 22b will be described later.

  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. The oxidant gas flow channel 30 is configured by arranging a plurality of wave-shaped flow channel grooves extending in the horizontal direction in the gravity direction. An inlet buffer portion 32 a and an outlet buffer portion 32 b each having a plurality of embosses are provided in the vicinity of the inlet and the outlet of the oxidant gas flow path 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 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.

  The inlet buffer portion 32a and the oxidant gas inlet communication hole 18a communicate with each other through a plurality of inlet connection channels 33a. The outlet buffer portion 32b and the oxidant gas outlet communication hole 18b communicate with each other through a plurality of outlet connection channels 33b.

  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. The fuel gas channel 34 is configured by arranging a plurality of wave-shaped channel grooves extending in the horizontal direction in the direction of gravity. An inlet buffer portion 36a and an outlet buffer portion 36b each having a plurality of embosses are provided in the vicinity of the inlet and the outlet of the fuel gas channel 34.

  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 apex position is spaced upward from the center in the height direction (arrow C direction). Is set. The outlet buffer portion 36b 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 36a and the fuel gas inlet communication hole 20a communicate with each other through a plurality of inlet connection channels 37a. The outlet buffer portion 36b and the fuel gas outlet communication hole 20b communicate with each other through a plurality of outlet connection channels 37b.

  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 channel 38 circulates the cooling medium over the electrode range of the electrolyte membrane / electrode structure 12, and the inlet buffer unit 40 a and the outlet buffer are provided near the inlet and the outlet of the cooling medium channel 38. Part 40b.

  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. The shape of the communication hole on the refrigerant surface of the cathode side separator 14 is the same as that of the anode side separator 16.

  As shown in FIG. 1, the inlet buffer section 40a 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 centered in the height direction (direction of arrow C). ) From the lower side. The outlet buffer 40b 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. 4, the cooling medium inlet communication hole 22 a has an opening shape set to be a long rectangular shape along the flow direction (arrow B direction) of the cooling medium flow path 38. 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 first region 22a1 is provided with an inclined portion 41a whose opening cross-sectional area decreases in the direction closer to the inlet buffer portion 40a. The inclined portion 41a is inclined in the direction away from the inlet buffer portion 40a in the horizontal direction (arrow B direction).

  In the cooling medium inlet communication hole 22a, inlet connection flow paths 42au1 and 42au2 are formed in the vicinity of the upper cooling medium inlet communication hole 22a, and the inlet connection flow path 42ad1 in the vicinity of the lower cooling medium inlet communication hole 22a. , 42ad2 are formed.

  The inlet connection flow path 42au1 is provided in the upper inclined portion 41a, and communicates the upper cooling medium inlet communication hole 22a with the inlet buffer portion 40a. The inlet connection channel 42ad1 is provided in the lower inclined portion 41a, and communicates the lower cooling medium inlet communication hole 22a and the inlet buffer portion 40a.

  The inlet connection flow path 42au1 extends in a direction orthogonal to the inclined portion 41a, that is, extends inclined toward the inlet buffer portion 40a, and is set to have the same flow path length. The inlet connection flow path 42ad1 extends in a direction perpendicular to the inclined portion 41a, that is, extends inclined toward the inlet buffer portion 40a, and is set to have the same flow path length. The inlet connection channel 42au1 and the inlet connection channel 42ad1 are set to different numbers of channels, but may be set to the same number of channels.

  The inlet connection flow path 42 au 2 communicates the cooling medium inlet communication hole 22 a on the upper side and the cooling medium flow path 38. The inlet connection flow path 42ad2 communicates the cooling medium inlet communication hole 22a on the lower side and the cooling medium flow path 38.

  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 first region 22b1 is provided with an inclined portion 41b whose opening cross-sectional area decreases in the direction approaching the outlet buffer portion 40b. The inclined portion 41b is inclined in a direction away from the outlet buffer portion 40b in the horizontal direction (arrow B direction). The inclined portion 41b on the outlet side may be provided as necessary, and at least the inclined portion 41a on the inlet side may be provided.

  In the cooling medium outlet communication hole 22b, outlet connection channels 42bu1 and 42bu2 are formed in the vicinity of the upper cooling medium outlet communication hole 22b, and the outlet connection channel 42bd1 in the vicinity of the lower cooling medium outlet communication hole 22b. 42bd2 are formed.

  The outlet connection channel 42bu1 is provided in the upper inclined portion 41b, and communicates the upper cooling medium outlet communication hole 22b and the outlet buffer portion 40b. The outlet connection channel 42bd1 is provided in the lower inclined portion 41b, and communicates the lower cooling medium outlet communication hole 22b and the outlet buffer portion 40b.

  The outlet connection channels 42bu1 and 42bd1 extend in a direction perpendicular to the inclined portion 41b, that is, extend inclined to the outlet buffer portion 40b side, and are set to have the same channel length. The outlet connection channel 42bu1 and the outlet connection channel 42bd1 are set to different numbers of channels, but may be set to the same number of channels.

  The outlet connection flow path 42bu2 communicates the cooling medium outlet communication hole 22b on the upper side with the cooling medium flow path 38. The outlet connection flow path 42bd2 communicates the cooling medium outlet communication hole 22b on the lower side with the cooling medium flow path 38.

  As shown in FIG. 1, a first seal member 43 is integrally formed on the surfaces 14 a and 14 b of the cathode separator 14 so as to go around the outer peripheral edge of the cathode 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 43 and the second seal member 44, 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.

  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 this embodiment, at least the cooling medium inlet communication hole 22a is provided with the inclined portion 41a whose opening cross-sectional area decreases in the direction close to the inlet buffer portion 40a. The inclined portion 41a is formed with a plurality of inlet connection channels 42au1 and 42ad1 that are orthogonal to the inclined portion 41a, that is, inclined toward the inlet buffer portion 40a. For this reason, the cooling medium is led out from each of the inlet connection channels 42au1 and 42ad1 toward the center of the inlet buffer 40a. Therefore, the cooling medium can be reliably supplied to the inlet buffer portion 40a not only on the both ends in the width direction adjacent to the pair of cooling medium inlet communication holes 22a but also on the center portion in the width direction.

  Here, a cooling medium flow path is formed using a structure (conventional example) in which the cooling medium inlet communication hole 22a is not provided with an inclined part (refer to the two-dot chain line in FIG. 4) and a structure in which the inclined part 41a is provided (example of the present application). The distribution state of the cooling medium supplied to 38 was compared. As a result, as shown in FIG. 5, in the structure of the conventional example, a large amount of the cooling medium is supplied directly from the cooling medium inlet communication hole 22a to the cooling medium flow path 38, and on the central side of the inlet buffer 40a. A small amount of cooling medium is bypassed.

  Therefore, a large amount of cooling medium is supplied to both ends in the width direction of the cooling medium flow path 38 (near the cooling medium inlet communication hole 22a), and only a small amount of cooling medium is supplied to the central portion of the power generation unit. is there. Therefore, there is a problem that a large temperature difference occurs in the width direction in the cooling medium flow path 38 and durability and power generation stability are lowered.

  On the other hand, in the example of the present application, the inlet connection flow path 42au1 and the inlet connection flow path 42ad1 communicating with the pair of inclined portions 41a are inclined toward the inlet buffer portion 40a. Thereby, the cooling medium led out to the inlet buffer part 40a from the inlet connection flow path 42au1 and the inlet connection flow path 42ad1 is satisfactorily supplied also to the center side in the width direction of the inlet buffer part 40a (see FIG. 6). . For this reason, the cooling medium can be uniformly supplied over the entire width direction of the inlet buffer 40a.

  Accordingly, the cooling medium can be satisfactorily supplied to the entire inlet buffer 40a, and the cooling medium can be evenly supplied to the entire cooling medium flow path 38. This makes it possible to supply the cooling medium evenly over the entire surface of the power generation unit with a simple configuration, and to suppress local degradation and generation of stagnant water due to non-uniform temperature as much as possible. An effect is obtained.

  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.

  Furthermore, in the present embodiment, the fuel cell 11 includes 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. However, the present invention is not limited to this. For example, a unit cell constituted by two MEAs and three separators (MEA interposed between separators) may be provided and applied to a cooling medium flow path constituted between the unit cells.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 11 ... Fuel cell 12 ... Electrolyte membrane electrode assembly 14 ... Cathode side separator 16 ... 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 ... Region 22b ... Cooling medium outlet communication hole 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 41a, 41b ... Inclined part 42ad1, 42ad2, 42au1, 42au2 ... Inlet connection flow path 42bd1, 42bd2, 42bu1, 42bu2, ... outlet connection flow path

Claims (3)

An electrolyte membrane / electrode structure provided with electrodes on each side of the electrolyte membrane and a fuel cell in which a separator is laminated, and a plurality of the fuel cells are laminated, and between the separators adjacent to each other A cooling medium flow path for flowing 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. A pair of cooling medium inlet communication holes are provided on both sides in the flow path width direction on the inlet side of the flow path, and the flow path width direction is provided 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,
At least the cooling medium inlet communication hole has an opening shape that is set to be a long rectangular shape along the flow direction of the cooling medium flow path, and has an opening cross-sectional area that decreases in a direction close to the buffer portion. A fuel cell stack comprising an inclined portion. 2. The fuel cell stack according to claim 1, wherein at least the cooling medium inlet communication hole and the buffer portion communicate with each other through a plurality of connection channels.
The fuel cell stack, wherein the plurality of connecting flow paths are set to have the same flow path length.   3. The fuel cell stack according to claim 2, wherein the plurality of connecting flow paths are inclined toward the buffer portion side with respect to the flow direction of the cooling medium flow path and are arranged in parallel to each other. Fuel cell stack.

Images