JP4165875B2 - Fuel cell stack - Google Patents

Description

  In the present invention, an electrolyte / electrode structure having an electrolyte sandwiched between a pair of electrodes has a fuel cell sandwiched between a pair of separators, and a stacked body in which a plurality of the fuel cells are stacked is housed in a box-shaped casing. The present invention relates to a fuel cell stack.

  For example, a polymer electrolyte fuel cell has an electrolyte membrane / electrode structure in which an anode electrode and a cathode electrode are respectively provided on both sides of an electrolyte membrane (electrolyte) made of a polymer ion exchange membrane (cation exchange membrane). Is sandwiched between separators. This type of fuel cell normally comprises a fuel cell stack in which a predetermined number of electrolyte membrane / electrode structures and separators are alternately stacked.

  In this fuel cell, a fuel gas supplied to the anode side electrode, for example, a gas mainly containing hydrogen (hereinafter also referred to as a hydrogen-containing gas) is ionized with hydrogen on an electrode catalyst, and is cathoded through an electrolyte membrane. Move to the side electrode side. Electrons generated during that time are taken out to an external circuit and used as direct current electric energy. The cathode side electrode is supplied with an oxidant gas, for example, a gas mainly containing oxygen or air (hereinafter also referred to as an oxygen-containing gas). And oxygen reacts to produce water.

  By the way, when the fuel cell stack is used, for example, for in-vehicle use, it is necessary to stack a large number (for example, several hundreds) of fuel cells in order to obtain a desired high output. At that time, a load is likely to act on the fuel cell stack in the stacking direction of the fuel cells and the direction orthogonal to the stacking direction depending on the traveling state of the vehicle. For this reason, in the configuration in which the fuel cell stack is tightened by bolts (tie rods) extending in the stacking direction, there is a problem that the fuel cell stack is easily deformed particularly in a direction perpendicular to the stacking direction.

  Therefore, for example, a fuel cell holding device disclosed in Patent Document 1 is known. In this patent document 1, as shown in FIG. 11, the housing 2 surrounding the cell laminated body 1 in which a plurality of MEAs and separators are laminated is provided. The housing 2 includes a wall 3a that surrounds the upper, lower, left, and right outer peripheries of the cell stack 1, and a partition wall 3b that partitions the cell stacks 1 from each other.

  A tension member 4 made of a metal member is embedded in the wall 3 a of the housing 2. The tension member 4 extends in the stacking direction, improves the rigidity and strength of the housing 2 to prevent deformation, and can easily receive the tightening load of the cell stack 1.

JP 2003-77501 A (paragraphs [0010], [0011], [0018], FIG. 2)

  As described above, in Patent Document 1, a plurality of sets of cell stacks 1 are partitioned and accommodated by the wall 3a and the partition wall 3b constituting the housing 2. However, the cell stack 1 is likely to have dimensional variations in manufacturing, and a gap is generated between the cell stack 1 and the inner wall of the housing 2. As a result, the cell stack 1 may be displaced in a direction perpendicular to the stacking direction, and there is a problem that the reaction gas leaks.

  The present invention solves this type of problem, and with a simple and inexpensive configuration, stacked fuel cells can be securely held in a box-shaped casing, and gas leakage due to misalignment or the like may occur in each fuel cell. An object of the present invention is to provide a fuel cell stack capable of satisfactorily preventing the occurrence.

  In the fuel cell stack according to the present invention, an electrolyte / electrode structure having an electrolyte sandwiched between a pair of electrodes has a fuel cell sandwiched between a pair of separators, and a stacked body in which a plurality of the fuel cells are stacked is a box. In a cylindrical casing. And the clearance gap between the outer periphery which cross | intersects the lamination direction of a laminated body, and the inner wall of a box-shaped casing is adjusted via a clearance gap adjustment mechanism.

Gap distance adjusting mechanism, crossing the gap between the outer peripheral and the inner wall of the box-like casing of the stack, and a plurality of pressing plates which are disposed across the fuel cell of the predetermined number, the pressing plate in the stacking direction of the laminate toward the outer circumference of Ru and a depressible adjusting member. Furthermore, it is preferable that a buffer member is interposed between the pressing plate and the outer periphery of the laminate.

  Furthermore, the gap adjusting mechanism preferably includes a resin member that fills the gap between the outer periphery of the laminate and the inner wall of the box-shaped casing.

  In the fuel cell stack according to the present invention, since the gap between the outer periphery of the laminate and the inner wall of the box-shaped casing is adjusted, the stack does not shift in the direction perpendicular to the stacking direction in the box-shaped casing. Thereby, especially when the fuel cell stack is used for in-vehicle use, it is possible to prevent the stack from being displaced due to vibration or the like, and to prevent gas leakage and the like as much as possible.

  Further, the clearance adjustment mechanism only needs to use a pressing plate and an adjustment member (for example, a screw). For this reason, the configuration of the gap adjustment mechanism is effectively simplified, and the gap adjustment mechanism can be configured economically. Furthermore, since the buffer member is interposed between the pressing plate and the outer periphery of the laminated body, it is possible to satisfactorily absorb variations in the outer peripheral dimensions of the fuel cells.

  Furthermore, since the resin member is filled in the gap between the outer periphery of the laminate and the inner wall of the box-shaped casing, it is possible to reliably prevent the laminate from being displaced with a simpler configuration.

  FIG. 1 is a schematic overall perspective view of a fuel cell stack 10 according to a first embodiment of the present invention, and FIG. 2 is a partial sectional side view of the fuel cell stack 10.

  The fuel cell stack 10 includes a stacked body 14 in which a plurality of fuel cells 12 are stacked in the direction of arrow A. Terminal plates 16a and 16b, insulator plates 18a and 18b, End plates 20a and 20b are sequentially arranged outward.

  The end plates 20 a and 20 b constitute end plates of the box-shaped casing 22, and the laminate 14 is accommodated in the box-shaped casing 22. The box-shaped casing 22 includes a lower plate 24a, an upper plate 24b, and side plates 24c and 24d, which are fixed to the end plates 20a and 20b via bolts 25.

  As shown in FIG. 3, the fuel cell 12 includes an electrolyte membrane / electrode structure (electrolyte / electrode structure) 30, and first and second metal separators having a thin plate shape that sandwich the electrolyte membrane / electrode structure 30. 32, 34.

  An oxidant gas supply for supplying an oxidant gas, for example, an oxygen-containing gas, to one end edge of the fuel cell 12 in the long side direction (arrow B direction in FIG. 3) in communication with the arrow A direction. A communication hole 36a, a cooling medium supply communication hole 38a for supplying a cooling medium, and a fuel gas discharge communication hole 40b for discharging a fuel gas, for example, a hydrogen-containing gas, are provided.

  The other end edge in the long side direction of the fuel cell 12 communicates with each other in the direction of the arrow A, the fuel gas supply communication hole 40a for supplying fuel gas, and the cooling medium discharge communication hole for discharging the cooling medium. 38b and an oxidizing gas discharge communication hole 36b for discharging the oxidizing gas are provided.

  The electrolyte membrane / electrode structure 30 includes, for example, a solid polymer electrolyte membrane 42 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 44 and a cathode side electrode 46 that sandwich the solid polymer electrolyte membrane 42. With.

  The anode side electrode 44 and the cathode side electrode 46 are composed of a gas diffusion layer made of carbon paper or the like, and an electrode catalyst layer in which porous carbon particles carrying a platinum alloy on the surface are uniformly applied to the surface of the gas diffusion layer. And have. The electrode catalyst layers are bonded to both surfaces of the solid polymer electrolyte membrane 42 so as to face each other with the solid polymer electrolyte membrane 42 interposed therebetween.

  A fuel gas flow path 48 that connects the fuel gas supply communication hole 40 a and the fuel gas discharge communication hole 40 b is formed on the surface 32 a of the first metal separator 32 facing the electrolyte membrane / electrode structure 30. The fuel gas channel 48 is constituted by, for example, a plurality of grooves extending in the arrow B direction. On the surface 32b of the first metal separator 32, a cooling medium flow path 50 that connects the cooling medium supply communication hole 38a and the cooling medium discharge communication hole 38b is formed. The cooling medium flow path 50 is configured by a plurality of grooves extending in the arrow B direction.

  The surface 34a of the second metal separator 34 facing the electrolyte membrane / electrode structure 30 is provided with, for example, an oxidant gas flow path 52 composed of a plurality of grooves extending in the direction of arrow B, and this oxidant gas. The flow path 52 communicates with the oxidant gas supply communication hole 36a and the oxidant gas discharge communication hole 36b. A cooling medium flow path 50 is integrally formed on the surface 34 b of the second metal separator 34 so as to overlap the surface 32 b of the first metal separator 32.

  A first seal member 54 is integrally formed on the surfaces 32 a and 32 b of the first metal separator 32. The first seal member 54 surrounds the fuel gas supply communication hole 40a, the fuel gas discharge communication hole 40b, and the fuel gas flow path 48 on the surface 32a so as to communicate with each other, and on the surface 32b, the cooling medium supply communication hole 38a, The medium discharge communication hole 38b and the cooling medium flow path 50 are surrounded and communicated with each other.

  A second seal member 56 is integrally formed on the surfaces 34 a and 34 b of the second metal separator 34. The second seal member 56 surrounds and communicates the oxidant gas supply communication hole 36a, the oxidant gas discharge communication hole 36b, and the oxidant gas flow path 52 on the surface 34a, while the cooling medium supply communication hole on the surface 34b. 38a, the cooling medium discharge communication hole 38b, and the cooling medium flow path 50 are surrounded and communicated.

  As shown in FIG. 1, the fuel cell stack 10 includes a gap adjusting mechanism 60 for adjusting the gap between the outer periphery intersecting the stacking direction (arrow A direction) of the stacked body 14 and the inner wall of the box-shaped casing 22. .

  The gap adjusting mechanism 60 is screwed into the side plate 24c and a plurality of side pressing plates 62 arranged in the gap between the inner wall of the side plate 24c constituting the box-shaped casing 22 and the outer peripheral side surface of the laminated body 14 and In a gap between a plurality of adjustment screws (adjustment members) 64 capable of pressing the partial pressing plate 62 toward the laminate 14, and the inner wall of the upper plate 24 b constituting the box-shaped casing 22 and the outer peripheral upper surface of the laminate 14. A plurality of upper pressing plates 66 arranged, and a plurality of adjusting screws (adjusting members) 68 that can be screwed into the upper plate 24b and press the upper pressing plate 66 toward the laminated body 14.

  As shown in FIG. 4, the side pressing plate 62 is made of a metal, for example, SUS material, straddles a predetermined number of fuel cells 12 and extends in the height direction of the fuel cells 12 (in FIG. 1, an arrow). (C direction) It arrange | positions corresponding to a substantially intermediate part. The side pressing plate 62 has a function of holding the laminated body 14 in the direction of arrow B in the box-shaped casing 22.

  While the resin plate 70 is fixed to the side pressing plate 62, each fuel cell 12 is provided with a frame-shaped resin guide 72 covering the outer periphery, and the resin plate 70 and the resin guide 72 are connected to each other. Contact. The side plate 24 c is formed with a screw hole 74 into which the adjustment screw 64 is screwed, and an opening 76 that accommodates the side pressing plate 62 and the resin plate 70.

  The upper pressing plate 66 is disposed across a predetermined number of fuel cells 12 and corresponding to a substantially middle portion of the fuel cells 12 in the horizontal direction (in the direction of arrow B in FIG. 1). Has a function of holding in the direction of arrow C. The upper pressing plate 66 and the adjusting screw 68 are configured in the same manner as the side pressing plate 62 and the adjusting screw 64, and detailed description thereof is omitted.

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

  First, as shown in FIG. 1, fuel gas such as hydrogen-containing gas is supplied into the fuel cell stack 10 from the fuel gas supply communication hole 40a of the end plate 20a, and oxygen is supplied from the oxidant gas supply communication hole 36a. An oxidant gas such as a contained gas is supplied. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied from the cooling medium supply communication hole 38a. Therefore, in the stacked body 14, the fuel gas, the oxidant gas, and the cooling medium are supplied in the arrow A1 direction to the plurality of fuel cells 12 stacked in the arrow A direction.

  Therefore, as shown in FIG. 3, the fuel gas is introduced into the fuel gas flow path 48 of the first metal separator 32 through the fuel gas supply communication hole 40a, and along the anode side electrode 44 of the electrolyte membrane / electrode structure 30. Move. On the other hand, the oxidant gas is introduced into the oxidant gas flow path 52 of the second metal separator 34 from the oxidant gas supply communication hole 36 a and moves along the cathode side electrode 46 of the electrolyte membrane / electrode structure 30.

  Therefore, in each electrolyte membrane / electrode structure 26, the fuel gas supplied to the anode side electrode 44 and the oxidant gas supplied to the cathode side electrode 46 are consumed by an electrochemical reaction in the electrode catalyst layer, Power generation is performed.

  Next, the fuel gas consumed by being supplied to the anode side electrode 44 is discharged to the fuel gas discharge communication hole 40b, flows in the direction of arrow A2, and is discharged to the outside from the end plate 20a. Similarly, the oxidant gas supplied to and consumed by the cathode side electrode 46 flows in the direction of arrow A2 along the oxidant gas discharge communication hole 36b, and is then discharged from the end plate 20a to the outside.

  The cooling medium flows in the direction of arrow B after being introduced into the cooling medium flow path 50 between the first and second metal separators 32 and 34 from the cooling medium supply communication hole 38a. The cooling medium cools the electrolyte membrane / electrode structure 30 and then moves through the cooling medium discharge communication hole 38b in the arrow A2 direction and is discharged from the end plate 20a.

  In this case, in the first embodiment, as shown in FIG. 1, a gap adjusting mechanism 60 is provided to adjust the gap between the outer periphery intersecting the stacking direction of the stacked body 14 and the inner wall of the box-shaped casing 22. It has been.

  Therefore, as shown in FIG. 4, when the adjusting screw 64 is screwed into the screw hole 74 of the side plate 24c, the tip of the adjusting screw 64 pushes the side pressing plate 62 inwardly (in the direction of arrow B1) of the box-shaped casing 22. . Therefore, the side pressing plate 62 presses the resin guide 72 via the resin plate 70, and a predetermined number of fuel cells 12 are integrally pressed in the direction of the arrow B1 (see FIG. 5). Therefore, the laminated body 14 moves in the direction of the arrow B1 and is pressed against the side plate 24d, and the outer side surfaces are held by the side plate 24d and the side pressing plate 62 (see FIG. 1).

  Similarly, as shown in FIG. 1, the upper pressing plate 66 presses the outer peripheral upper surface of the laminate 14 vertically downward by screwing the adjusting screw 68 screwed into the upper plate 24b. For this reason, the laminated body 14 is pressed against the lower plate 24 a, and the outer peripheral upper and lower surfaces are held by the lower plate 24 a and the upper pressing plate 66.

  Thereby, the laminated body 14 is easily and reliably held in the box-shaped casing 22 in a direction orthogonal to the laminating direction, and the laminated body 14 does not shift in the arrow B direction or the arrow C direction. Therefore, in particular, when the fuel cell stack 10 is used for in-vehicle use, it is possible to prevent the stack 14 from being displaced due to vibration or the like, and to prevent the leakage of fuel gas and oxidant gas as much as possible. The effect of being able to be obtained.

  Moreover, the gap adjusting mechanism 60 only needs to use the side pressing plate 62 and the adjusting screw 64, and the upper pressing plate 66 and the adjusting screw 68. For this reason, the configuration of the gap adjustment mechanism 60 can be effectively simplified, and the gap adjustment mechanism 60 can be configured economically.

  Further, as shown in FIGS. 4 and 5, a resin plate 70 is fixed to the side pressing plate 62, while each fuel cell 12 is provided with a frame-shaped resin guide 72 covering the outer periphery, The resin plate 70 and the resin guide 72 are in contact with each other. As a result, even if there is a variation in the outer peripheral dimension of each fuel cell 12, the variation can be absorbed through the elasticity of the resin plate 70 and the resin guide 72.

  At this time, as shown in FIG. 6, if a buffer member 80 such as rubber is interposed between the resin plate 70 and the resin guide 72, the variation in the outer peripheral dimension of each fuel cell 12 is more reliably absorbed. . Therefore, there is an advantage that it is possible to prevent the deviation of the stacked body 14 as much as possible.

  In the first embodiment, the side pressing plate 62 and the upper pressing plate 66 are arranged on the side plate 24c and the upper plate 24b, but in addition to this, the side plate 24d and the lower plate 24a also have The side pressing plate 62 and the upper pressing plate 66 may be disposed.

  FIG. 7 is a partially enlarged cross-sectional view of a fuel cell stack 90 according to the second embodiment of the present invention. The same components as those of the fuel cell stack 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Similarly, in the third and fourth embodiments described below, detailed description thereof is omitted.

  The gap adjusting mechanism 92 constituting the fuel cell stack 90 fills the gap between the outer periphery of the laminate 14 and the inner wall of the side plate 24c (and the upper plate (not shown)) constituting the box-shaped casing 22, that is, the opening 76. A resin member 94 is provided. In the side plate 24c, a resin filling port 96 communicating with the opening 76 and a pin insertion port 98 are formed, and the side pressing plate 62 is pressed toward the laminated body 14 in the pin insertion port 98. Pin 100 can be inserted.

  In the second embodiment configured as described above, as shown in FIG. 8, in a state where the pin 100 is inserted into the pin insertion port 98 and the side pressing plate 62 is pressed against the outer periphery of the laminate 14, Resin is filled into the opening 76 from the resin filling port 96. When the resin is cured, a resin member 94 is formed in the opening 76, and the stacked body 14 is held immovably in a direction orthogonal to the stacking direction (see FIG. 7).

  Therefore, in the second embodiment, the same effects as in the first embodiment can be obtained, for example, it is possible to reliably prevent the stack 14 from shifting.

  FIG. 9 is a partially enlarged cross-sectional view of a fuel cell stack 110 according to the third embodiment of the present invention.

  The gap adjusting mechanism 112 constituting the fuel cell stack 110 includes a resin member 114 filled between the outer periphery of the stacked body 14 and the opening 76 of the side plate 24c. Thereby, in 3rd Embodiment, the effect that the shift | offset | difference of the laminated body 14 can be reliably prevented with a much simpler structure is acquired.

  FIG. 10 is a partially enlarged cross-sectional view of a fuel cell stack 120 according to the fourth embodiment of the present invention.

  The gap adjusting mechanism 122 constituting the fuel cell stack 120 includes a resin member 124 filled between the outer periphery of the stacked body 14 and the opening 76 of the side plate 24 c constituting the box-shaped casing 22. The resin guide 72 is provided with a saw-toothed uneven portion 126 at the end, and the resin member 124 is formed into a shape that meshes with the uneven portion 126.

Therefore, in the fourth embodiment, since the resin member 124 meshes with the concavo-convex portion 126 of the resin guide 72, it is possible to more reliably prevent each fuel cell 12 from shifting in the stacking direction. It is done.

1 is a schematic overall perspective view of a fuel cell stack according to a first embodiment of the present invention. It is a partial cross section side view of the said fuel cell stack. It is a disassembled perspective view of the fuel cell which comprises the said fuel cell stack. It is principal part cross-sectional explanatory drawing of the clearance gap adjustment mechanism which comprises the said fuel cell stack. It is operation | movement explanatory drawing of the said clearance gap adjustment mechanism. It is a section explanatory view in the state where a buffer member was interposed in the gap adjustment mechanism. It is a partially expanded sectional view of the fuel cell stack which concerns on the 2nd Embodiment of this invention. It is operation | movement explanatory drawing of the clearance gap adjustment mechanism which comprises the said fuel cell stack. It is a partial expanded sectional view of the fuel cell stack which concerns on the 3rd Embodiment of this invention. It is a partially expanded sectional view of the fuel cell stack which concerns on the 4th Embodiment of this invention. FIG. 3 is a configuration explanatory diagram of a fuel cell holding device according to Patent Document 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 90, 110, 120 ... Fuel cell stack 12 ... Fuel cell 14 ... Laminated body 20a, 20b ... End plate 22 ... Box-shaped casing 24a ... Lower plate 24b ... Upper plate 24c, 24d ... Side plate 26, 30 ... Electrolyte membrane * Electrode structures 32, 34 ... Metal separator 42 ... Solid polymer electrolyte membrane 44 ... Anode side electrode 46 ... Cathode side electrode 48 ... Fuel gas passage 50 ... Coolant flow passage 52 ... Oxidant gas passage 60, 92, 112 122 ... Gap adjusting mechanism 62 ... Side pressing plate 64, 68 ... Adjustment screw 66 ... Upper pressing plate 70 ... Resin plate 72 ... Resin guide 74 ... Screw hole 76 ... Opening 94, 114, 124 ... Resin member 96 ... Resin Filling port 98 ... Pin insertion port 100 ... Pin 126 ... Uneven portion

Claims (4)

A fuel cell stack in which an electrolyte / electrode structure having an electrolyte sandwiched between a pair of electrodes has a fuel cell sandwiched between a pair of separators, and a stacked body in which a plurality of the fuel cells are stacked is housed in a box-shaped casing Because
A gap adjusting mechanism for adjusting the gap between the outer circumference intersecting the stacking direction of the laminate and the inner wall of the box-shaped casing ;
The gap adjusting mechanism includes a plurality of pressing plates arranged across a predetermined number of the fuel cells in the gap between the outer periphery of the laminate and the inner wall of the box-shaped casing;
An adjustment member capable of pressing the pressing plate toward the outer periphery intersecting the stacking direction of the stacked body;
Fuel cell stack according to claim Rukoto equipped with. The fuel cell stack according to claim 1, wherein a resin plate is fixed to the pressing plate,
The fuel battery, a fuel cell stack according to claim Rukoto resin guide is provided in contact with the resin plate covers the outer periphery. 3. The fuel cell stack according to claim 1 , wherein a buffer member is interposed between the pressing plate and the outer periphery of the stacked body. The fuel cell stack according to claim 1 Symbol placement, the gap adjustment mechanism, a fuel cell stack, characterized by comprising a resin member filled in the gap between the outer and inner walls of the box-like casing of the laminate.

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