JP2013206604A - Fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a unit cell on the center side in the stacking direction from deflecting so as to hang in the direction of gravity, by a simple and economic configuration.SOLUTION: A fuel cell stack 10 comprises a plurality of unit cells 12 to be stacked. The unit cells 12 are integrated by a resin clip 98 constituting a fastening mechanism 90. In the fuel cell stack 10, a unit cell 12a arranged on the center side in the stacking direction is set so that a fastening load by a resin clip 98constituting a fastening mechanism 90a is larger than a fastening load by a resin clip 98 attached to unit cells 12 arranged on both end sides in the stacking direction.

Description

  The present invention includes a unit 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 laminated, each unit cell being integrated by a fastening member, and a plurality of unit cells. The present invention relates to a fuel cell stack in which the unit 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 a solid polymer electrolyte membrane made of a polymer ion exchange membrane is sandwiched between separators. Power generation cells (unit cells). In this type of fuel cell, several tens to several hundreds of unit cells are usually stacked and used as an in-vehicle fuel cell stack.

  In the on-vehicle fuel cell stack, it is necessary to accurately position the fuel cell itself and the fuel cells. For example, the fuel cell stack disclosed in Patent Document 1 is known.

  The fuel cell stack is provided on an outer peripheral portion of at least one separator among the connection member that integrally holds a plurality of separators in the stacking direction and the separator that is integrally held by the connection member. And a resin guide portion that protrudes outward from the outer peripheral portion and receives a load from the outside.

  As a result, it is possible to satisfactorily prevent a decrease in sealing performance due to deviation of the fuel cell itself, and to reliably prevent a short circuit of the separator.

JP 2008-27761 A

  By the way, in the fuel cell stack, end plates are disposed at both ends of the plurality of fuel cells in the stacking direction, and a tightening load is applied between the end plates in the stacking direction.

  At that time, particularly when several hundred fuel cells (unit cells) are stacked for in-vehicle use, the tightening load may not be sufficiently transmitted to the fuel cells arranged on the center side of the stack. For this reason, the fuel cell on the center side in the stacking direction has a problem that the seal linear pressure tends to decrease, and the deflection occurs so that the center side of the stack hangs downward.

  The present invention solves this type of problem, and with a simple and economical configuration, it is possible to reliably prevent the unit cell at the center in the stacking direction from bending so as to hang downward in the direction of gravity. An object is to provide a fuel cell stack.

  The present invention includes a unit 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 laminated, each unit cell being integrated by a fastening member, and a plurality of unit cells. The present invention relates to a fuel cell stack in which the unit cells are stacked.

  In this fuel cell stack, the unit cell disposed on the center side in the stacking direction is set to have a higher fastening load by the fastening member than the unit cells disposed on both ends in the stacking direction.

  Further, in this fuel cell stack, the fastening member includes a resin clip that is integrally inserted into a hole that is formed through the unit cell in the stacking direction, and the resin clip has both end surfaces in the stacking direction of the unit cell. And a first locking portion and a second locking portion that apply the fastening load for each unit cell, and the distance between the first locking portion and the second locking portion is It is preferable to adjust the fastening load by setting according to the thickness of the unit cells in the stacking direction.

  Furthermore, in this fuel cell stack, it is preferable that the unit cell separator disposed on the center side in the stacking direction has a greater thickness in the stacking direction than the unit cell separator disposed on both ends in the stacking direction. .

  According to the present invention, the fastening load of the unit cell arranged on the center side in the stacking direction is set larger than the fastening load of the unit cell arranged on both ends in the stacking direction. For this reason, the unit cell on the central side in the stacking direction in which the tightening load in the stacking direction is difficult to be transmitted can be reliably prevented from bending downward in the gravitational direction with a simple and economical configuration.

1 is a schematic side view of a fuel cell stack according to a first embodiment of the present invention. It is principal part sectional drawing of the said fuel cell stack. It is a disassembled perspective explanatory drawing of the unit cell which comprises the said fuel cell stack. It is front explanatory drawing of the 2nd separator which carries out the said unit cell. It is front explanatory drawing of the 3rd separator which comprises the said unit cell. It is a disassembled perspective explanatory drawing of the unit cell which comprises the fuel cell stack which concerns on the 2nd Embodiment of this invention. It is principal part sectional drawing of the said fuel cell stack.

  As shown in FIGS. 1 and 2, the fuel cell stack 10 according to the first embodiment of the present invention is mounted on a fuel cell vehicle (not shown) such as a fuel cell electric vehicle, for example. Configure the stack.

  In the fuel cell stack 10, a plurality of unit cells 12 are stacked in the direction of arrow A (horizontal direction), and a terminal plate 14a, an insulating plate 16a, and an end plate 18a are disposed at one end of the unit cells 12 in the stacking direction. Is done. At the other end of the unit cell 12 in the stacking direction, a terminal plate 14b, an insulating plate 16b, and an end plate 18b are disposed (see FIG. 1).

  The end plates 18a and 18b are tightened by a plurality of tie rods 20 and nuts 22, and a desired tightening load is applied between the end plates 18a and 18b in the stacking direction. Instead of the tie rod 20 and the nut 22, a plurality of unit cells 12 may be accommodated in a casing having end plates 18a and 18b as end plates.

  2 and 3, the unit cell 12 includes a first separator 24, a first electrolyte membrane / electrode structure (MEA) 26a, a second separator 28, a second electrolyte membrane / electrode structure 26b, and a third separator. A separator 30 is provided.

  The 1st separator 24, the 2nd separator 28, and the 3rd separator 30 are comprised, for example by the steel plate, the stainless steel plate, the aluminum plate, the plating treatment steel plate, or the metal plate which gave the surface treatment for corrosion prevention to the metal surface. The 1st separator 24, the 2nd separator 28, and the 3rd separator 30 have a cross-sectional uneven | corrugated shape by pressing a metal thin plate into a waveform. The first separator 24, the second separator 28, and the third separator 30 may be carbon separators instead of metal separators.

  The first electrolyte membrane / electrode structure 26a and the second electrolyte membrane / electrode structure 26b include, for example, a solid polymer electrolyte membrane 32 in which a perfluorosulfonic acid thin film is impregnated with water, and the solid polymer electrolyte membrane 32. An anode electrode 34 and a cathode electrode 36 are provided.

  The anode electrode 34 constitutes a so-called stepped MEA having a smaller surface area than the solid polymer electrolyte membrane 32 and the cathode electrode 36. The anode electrode 34 and the cathode electrode 36 may have the same surface area, or the anode electrode 34 may have a larger surface area than the cathode electrode 36.

  The anode electrode 34 and the cathode electrode 36 have a gas diffusion layer (not shown) made of carbon paper or the like, and porous carbon particles carrying a platinum alloy on the surface are uniformly applied 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 32.

  As shown in FIG. 3, an oxidant gas, for example, an oxygen-containing gas (such as air) is supplied to the upper edge of the long side direction (arrow C direction) of the unit cell 12 in communication with each other in the arrow A direction. An oxidant gas inlet communication hole 40a for supplying a fuel gas, for example, a fuel gas inlet communication hole 42a for supplying a hydrogen-containing gas (hydrogen gas or the like) is provided.

  The lower end edge of the unit cell 12 in the long side direction (arrow C direction) communicates with each other in the direction of arrow A to discharge the fuel gas outlet communication hole 42b for discharging the fuel gas, and for discharging the oxidant gas. The oxidant gas outlet communication hole 40b is provided.

  A cooling medium inlet communication hole 44a is provided at one edge of the unit cell 12 in the short side direction (arrow B direction) so as to communicate with each other in the arrow A direction and supply a cooling medium. A cooling medium outlet communication hole 44b for discharging the cooling medium is provided at the other end edge in the short side direction.

  A surface 24a of the first separator 24 facing the first electrolyte membrane / electrode structure 26a is formed with a first fuel gas channel 46 that connects the fuel gas inlet communication hole 42a and the fuel gas outlet communication hole 42b. The first fuel gas channel 46 has a plurality of wave-like channel grooves extending in the direction of arrow C, and in the vicinity of the inlet (upper end) and outlet (lower end) of the first fuel gas channel 46, An inlet buffer portion 48 and an outlet buffer portion 50 each having a plurality of embossments are provided.

  A part of the cooling medium flow path 52 that connects the cooling medium inlet communication hole 44 a and the cooling medium outlet communication hole 44 b is formed on the surface 24 b of the first separator 24. The cooling medium flow path 52 has a back surface shape of the first fuel gas flow path 46 (and a second oxidant gas flow path 66 described later).

  As shown in FIG. 4, the surface 28a of the second separator 28 facing the first electrolyte membrane / electrode structure 26a is connected to the oxidant gas inlet communication hole 40a and the oxidant gas outlet communication hole 40b. An agent gas channel 54 is formed. The first oxidant gas channel 54 has a plurality of undulating channel grooves extending in the direction of arrow C. In the vicinity of the inlet (upper end) and the outlet (lower end) of the first oxidant gas channel 54, an inlet buffer unit 56 and an outlet buffer unit 58 each having a plurality of embosses are provided.

  As shown in FIG. 3, the second fuel gas flow that communicates the fuel gas inlet communication hole 42a and the fuel gas outlet communication hole 42b to the surface 28b of the second separator 28 facing the second electrolyte membrane / electrode structure 26b. A path 60 is formed. The second fuel gas channel 60 has a plurality of wave-shaped channel grooves extending in the direction of arrow C, and in the vicinity of the inlet (upper end) and outlet (lower end) of the second fuel gas channel 60, An inlet buffer unit 62 and an outlet buffer unit 64 having a plurality of embosses that protrude alternately on the front side and the back side are provided.

  As shown in FIG. 5, the second oxidation that communicates the oxidant gas inlet communication hole 40 a and the oxidant gas outlet communication hole 40 b with the surface 30 a of the third separator 30 toward the second electrolyte membrane / electrode structure 26 b. An agent gas channel 66 is formed.

  The second oxidant gas flow channel 66 has a plurality of wavy flow channel grooves extending in the direction of arrow C. In the vicinity of the inlet (upper end) and the outlet (lower end) of the second oxidant gas channel 66, an inlet buffer unit 68 and an outlet buffer unit 70 each having a plurality of embosses are provided.

  As shown in FIG. 3, a part of the cooling medium flow path 52 that connects the cooling medium inlet communication hole 44 a and the cooling medium outlet communication hole 44 b is formed on the surface 30 b of the third separator 30. The cooling medium flow path 52 is formed by overlapping the back surface shapes (wave shapes) of the first fuel gas flow path 46 and the second oxidant gas flow path 66 adjacent to each other.

  A first seal member 74 is integrally formed on the surfaces 24 a and 24 b of the first separator 24 around the outer peripheral edge of the first separator 24. On the surfaces 28a and 28b of the second separator 28, a second seal member 76 is integrally formed around the outer peripheral edge of the second separator 28, and on the surfaces 30a and 30b of the third separator 30, A third seal member 78 is integrally formed around the outer peripheral edge of the third separator 30.

  Examples of the first seal member 74, the second seal member 76, and the third seal member 78 include EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene, or acrylic rubber. A sealing material having elasticity such as a sealing material, a cushioning material, or a packing material is used.

  As shown in FIG. 3, the first separator 24 is provided with a plurality of outer supply holes 80 a and a plurality of inner supply holes 80 b that communicate the fuel gas inlet communication hole 42 a and the first fuel gas flow path 46. It is done. The first separator 24 is provided with a plurality of outer discharge hole portions 82 a and a plurality of inner discharge hole portions 82 b that communicate the fuel gas outlet communication hole 42 b and the first fuel gas flow path 46.

  As shown in FIGS. 3 and 4, the second separator 28 includes a plurality of supply holes 84 that communicate the fuel gas inlet communication hole 42 a and the second fuel gas flow channel 60, and a fuel gas outlet communication hole 42 b. A plurality of discharge holes 86 communicating with the second fuel gas channel 60 are formed.

  As shown in FIGS. 2 and 3, the fuel cell stack 10 includes a first electrolyte membrane / electrode structure 26 a and a first separator 24, a second separator 28, and a third separator 30 that constitute the unit cell 12. A fastening mechanism 90 for applying a fastening load in the stacking direction via the two electrolyte membrane / electrode structure 26b is provided.

  The fastening mechanism 90 is provided in a plurality of first hole portions 92 formed in a resin plate 92 a provided in a plurality of locations on the outer peripheral edge of the first separator 24, and in a plurality of locations on the outer peripheral edge of the second separator 28. A plurality of second holes 94 formed in the resin plate 94a and a plurality of third holes 96 formed in the resin plate 96a provided at a plurality of sites on the outer peripheral edge of the third separator 30 are provided.

  In each unit cell 12, the 1st hole part 92, the 2nd hole part 94, and the 3rd hole part 96 are set in the same position (coaxially) with respect to the lamination direction. In the unit cells 12 adjacent to each other, the arrangement positions of the first hole portion 92 to the third hole portion 96 are preferably offset from each other with respect to the stacking direction.

  As shown in FIG. 2, the diameter of the third hole 96 is set to be smaller than the diameters of the first hole 92 and the second hole 94, and the first hole 92 and the second hole 94 is set to the same diameter. A fastening member, for example, an insulating resin clip 98 is integrally inserted into the first hole 92, the second hole 94, and the third hole 96 in the stacking direction.

  Each resin clip 98 has a columnar neck portion 98a, and a head portion (first locking portion) 98b is formed at one end of the neck portion 98a, while a large portion is formed at the other end of the neck portion 98a. A diameter flange portion (second locking portion) 98c is provided. In the resin clip 98, a slit 98d extending from the head 98b side to the middle of the neck 98a is formed as necessary. In the resin clip 98, the length of the neck portion 98a, that is, the distance L from the end portion of the head portion 98b to the end portion of the flange portion 98c is set.

  The boundary portion between the neck 98 a and the head 98 b of the resin clip 98 is fitted into the third hole 96 of the third separator 30 and is locked to the end surface of the resin plate 96 a of the third separator 30. Further, the large-diameter flange portion 98c of the resin clip 98 is brought into contact with the end surface of the resin plate 92a of the first separator 24 by circling the first hole portion 92, whereby the first separator 24 and the second separator 28 are contacted. The third separator 30 is integrally held in the stacking direction via the first electrolyte membrane / electrode structure 26a and the second electrolyte membrane / electrode structure 26b.

The fastening mechanism 90a of at least one (or two or more) unit cells 12a arranged on the central side in the stacking direction is set to have a higher fastening load than the fastening mechanism 90 of the unit cells 12 arranged on both ends in the stacking direction. Is done. Specifically, the resin clip 98 _mid constituting the fastening mechanism 90a has a distance L1 from the end of the head 98b to the end of the flange 98c, and the distance L1 The length is set shorter than the distance L of the resin clip 98 to be formed (L1 <L).

  In the first embodiment, at least one of the first separator 24, the second separator 28, or the third separator 30 that constitutes the unit cell 12 a is the same member (the first separator 24, the second separator that constitutes the unit cell 12). 28 or the third separator 30), the thickness in the stacking direction (thickness from the end surface of the resin plate 92a to the end surface of the third hole 96) is set larger. Note that the distance L may be increased stepwise from both ends in the stacking direction toward the center.

  Further, when the thickness of the unit cells 12a in the stacking direction is sufficiently larger than the thickness of the unit cells 12 in the stacking direction, the distance L1 = distance L or the distance L1 <distance L can be set. For example, the thicknesses of the first separator 24 and the second separator 28 constituting the unit cell 12a may be set larger than the thicknesses of the first separator 24 and the second separator 28 constituting the unit cell 12.

  Further, the fastening member is not limited to the resin clip 98 and may be a metal clip. Moreover, you may fasten an outer periphery with a U-shaped clip.

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

  First, as shown in FIG. 3, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 40a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 42a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 44a.

  Therefore, the oxidant gas is introduced from the oxidant gas inlet communication hole 40a into the first oxidant gas channel 54 of the second separator 28 and the second oxidant gas channel 66 of the third separator 30 (FIG. 4). And FIG. 5). The oxidant gas moves in the direction of arrow C (the direction of gravity) along the first oxidant gas flow path 54, and is supplied to the cathode electrode 36 of the first electrolyte membrane / electrode structure 26a. It moves in the direction of arrow C along the agent gas flow channel 66 and is supplied to the cathode electrode 36 of the second electrolyte membrane / electrode structure 26b (see FIG. 3).

  On the other hand, as shown in FIG. 3, the fuel gas moves from the fuel gas inlet communication hole 42a to the surface 24b side of the first separator 24 through the outer supply hole 80a of the first separator 24. Further, the fuel gas is introduced from the inner supply hole 80b to the surface 24a side, moves in the direction of gravity (in the direction of arrow C) along the first fuel gas flow path 46, and the first electrolyte membrane / electrode structure 26a. It is supplied to the anode electrode 34.

  Further, the fuel gas moves to the surface 28 b side through the supply hole portion 84 of the second separator 28. For this reason, the fuel gas moves in the direction of arrow C along the second fuel gas channel 60 on the surface 28b side, and is supplied to the anode electrode 34 of the second electrolyte membrane / electrode structure 26b.

  Therefore, in the first electrolyte membrane / electrode structure 26a and the second electrolyte membrane / electrode structure 26b, the oxidant gas supplied to the cathode electrode 36 and the fuel gas supplied to the anode electrode 34 are converted into the electrode catalyst layer. Power is generated by being consumed by electrochemical reaction.

  Next, the oxidant gas consumed by being supplied to the cathode electrodes 36 of the first electrolyte membrane / electrode structure 26a and the second electrolyte membrane / electrode structure 26b is moved along the arrow A along the oxidant gas outlet communication hole 40b. Discharged in the direction.

  The fuel gas supplied to and consumed by the anode electrode 34 of the first electrolyte membrane / electrode structure 26a is led to the surface 24b side of the first separator 24 through the inner discharge hole 82b as shown in FIG. The The fuel gas led out to the surface 24b side is introduced into the outer discharge hole portion 82a and moves again to the surface 24a side. Therefore, the fuel gas is discharged from the outer discharge hole portion 82a to the fuel gas outlet communication hole 42b.

  Further, the fuel gas supplied and consumed to the anode electrode 34 of the second electrolyte membrane / electrode structure 26 b moves to the surface 28 a side through the discharge hole portion 86. This fuel gas is discharged to the fuel gas outlet communication hole 42b.

  On the other hand, the cooling medium supplied to the cooling medium inlet communication hole 44a is introduced into a cooling medium flow path 52 formed between the first separator 24 and the third separator 30 adjacent to each other as shown in FIG. After that, it circulates in the direction of arrow B. The cooling medium cools the first and second electrolyte membrane / electrode structures 26a and 26b, and then is discharged into the cooling medium outlet communication hole 44b.

In this case, in the first embodiment, as shown in FIG. 2, the fastening mechanism 90a of the unit cell 12a disposed on the center side in the stacking direction is more than the fastening mechanism 90 of the unit cell 12 disposed on both ends in the stacking direction. Also, the fastening load is set large. That is, the resin clip 98 _mid constituting the fastening mechanism 90 a is set with a distance L 1 from the end of the head 98 b to the end of the flange 98 _c , and the distance L 1 is the resin constituting the fastening mechanism 90. The length is set shorter than the distance L of the manufactured clip 98 (L1 <L).

  For this reason, the unit cell 12a is given a larger fastening load in the stacking direction than the other unit cells 12, and the entire unit cell 12a can be integrated firmly and reliably. Therefore, in particular, the unit cell 12a on the central side in the stacking direction, in which the tightening load in the stacking direction is difficult to be transmitted, can be reliably prevented from being bent downward in the gravitational direction with a simple and economical configuration. can get.

  Moreover, in the first embodiment, at least one of the first separator 24, the second separator 28, and the third separator 30 that constitutes the unit cell 12a is the same member (the first separator 24, the first separator 24 that constitutes the unit cell 12). The thickness in the stacking direction is set larger than that of the second separator 28 or the third separator 30).

  As a result, the compression amount in the thickness direction of the entire unit cell 12a becomes larger than the compression amount in the thickness direction of the other unit cells 12 as a whole. For this reason, in the unit cell 12a, the 1st seal member 74, the 2nd seal member 76, and the 3rd seal member 78 are compressed greatly, a seal linear pressure becomes high, and the fall of a seal linear pressure can be suppressed favorably. . Therefore, it is possible to prevent the unit cell 12a from bending downward in the direction of gravity as much as possible.

In the first embodiment, the unit cell 12a uses a resin clip 98 _mid instead of the resin clip 98, and the first separator 24, the second separator 28, or the third separator 30 constituting the unit cell 12a. At least one of these sets the thickness in the stacking direction to be larger than that of the same member constituting the unit cell 12, but the present invention is not limited to this.

For example, it is possible to use only the resin clip 98 _mid and the unit cell 12 a having the same thickness as the unit cell 12. On the other hand, a unit cell 12a having a thickness larger than that of the unit cell 12 can be used, and a resin clip 98 can also be used. Furthermore, the number of fastening mechanisms 90a on the center side in the stacking direction may be set larger than the number of fastening mechanisms 90 on both ends. The same applies to the second embodiment described below.

  As shown in FIGS. 6 and 7, the unit cell 102 constituting the fuel cell stack 100 according to the second embodiment of the present invention has an electrolyte membrane / electrode structure 26 between the first separator 104 and the second separator 106. Pinch. The same components as those of the fuel cell stack 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  A fuel gas flow path 108 is formed on a surface 104a of the first separator 104 facing the electrolyte membrane / electrode structure 26, and a surface 106a of the second separator 106 facing the electrolyte membrane / electrode structure 26 is An oxidant gas flow path 110 is formed. A cooling medium flow path 52 is formed between the surface 104b of the first separator 104 and the surface 106b of the second separator 106 that are adjacent to each other.

  In the fuel cell stack 100, the first separator 104 and the second separator 106 constituting the unit cell 102 are applied with a fastening load in the stacking direction by the fastening mechanism 112 with the electrolyte membrane / electrode structure 26 interposed therebetween.

  The fastening mechanism 112 is formed in a plurality of first holes 114 formed in the resin plate 114 a provided in the outer peripheral edge portion of the first separator 104 and a resin plate 116 a provided in the outer peripheral edge portion of the second separator 106. And a plurality of second holes 116.

  As shown in FIG. 7, the diameter of the second hole 116 is set to be smaller than the diameter of the first hole 114. A fastening member, for example, an insulating resin clip 98 is inserted into the first hole portion 114 and the second hole portion 116.

  A boundary portion between the neck portion 98 a and the head portion 98 b of the resin clip 98 is fitted into the second hole portion 116 of the second separator 106 and is locked to the end surface of the resin plate 116 a of the second separator 106. The large-diameter flange portion 98c of the resin clip 98 is brought into contact with the end surface of the resin plate 114a of the first separator 104 around the first hole portion 114, whereby the first separator 104 and the second separator 106 are The electrolyte membrane / electrode structure 26 is interposed and held integrally in the stacking direction.

  The fastening mechanism 112a of the unit cell 102a disposed on the center side in the stacking direction is set to have a higher fastening load than the fastening mechanism 112 of the unit cell 102 disposed on both ends in the stacking direction. Specifically, this is the same as in the first embodiment.

  Thus, in 2nd Embodiment, the fastening mechanism 112a of the unit cell 102a arrange | positioned at the lamination direction center side has a larger fastening load than the fastening mechanism 112 of the unit cell 102 arrange | positioned at the lamination direction both ends. Is set.

  For this reason, the unit cell 102a on the central side in the stacking direction, which is particularly difficult to transmit the tightening load in the stacking direction, can be reliably prevented from bending downward in the direction of gravity, etc. with a simple and economical configuration. The same effects as those of the first embodiment can be obtained.

DESCRIPTION OF SYMBOLS 10,100 ... Fuel cell stack 12, 102 ... Unit cell 24, 28, 30, 104, 106 ... Separator 26, 26a, 26b ... Electrolyte membrane and electrode structure 32 ... Solid polymer electrolyte membrane 34 ... Anode electrode 36 ... Cathode Electrode 40a ... Oxidant gas inlet communication hole 40b ... Oxidant gas outlet communication hole 42a ... Fuel gas inlet communication hole 42b ... Fuel gas outlet communication hole 44a ... Cooling medium inlet communication hole 44b ... Cooling medium outlet communication hole 46, 60 ... Fuel Gas channel 52... Cooling medium channel 54, 66. Oxidant gas channel 74, 76, 78... Seal member 90, 90 a, 112 ... Fastening mechanism 92, 94, 96, 114, 116. 96a, 114a, 116a ... resin plate 98,98 _{mid ...} resin clip 98a ... neck 98b ... head 98c ... flange portion 98d ... Lit

Claims (3)

A unit cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of the electrolyte membrane and a separator are stacked, each unit cell is integrated by a fastening member, and a plurality of unit cells are A stacked fuel cell stack,
The fuel cell stack, wherein the unit cell arranged on the center side in the stacking direction is set to have a larger fastening load by the fastening member than the unit cells arranged on both ends in the stacking direction. 2. The fuel cell stack according to claim 1, wherein the fastening member includes a resin clip that is integrally inserted into a hole formed through the unit cell in the stacking direction.
The resin clip has a first locking portion and a second locking portion that engage with both end surfaces of the unit cells in the stacking direction and apply the fastening load for each unit cell,
The fuel cell stack is characterized in that the fastening load is largely adjusted by setting the distance between the first locking portion and the second locking portion in accordance with the thickness of the unit cells in the stacking direction. .   3. The fuel cell stack according to claim 1, wherein the separator of the unit cell disposed on the center side in the stacking direction is thicker in the stacking direction than the separator of the unit cell disposed on both ends in the stacking direction. Is a large fuel cell stack.

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