JP5574746B2 - Fuel cell stack - Google Patents

Description

  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 at both ends in a stacking direction of the stack in which a plurality of the fuel cells are stacked. The present invention relates to a fuel cell stack in which first and second end plates are disposed.

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

  In this type of fuel cell stack, it is necessary to apply a good tightening load to the stacking direction in order to obtain a desired power generation performance and to exert a sealing function.

  Therefore, for example, in the fuel cell disclosed in Patent Document 1, the fuel cell stack 2 is accommodated in the stack case 1 as shown in FIG. The fuel cell stack 2 includes a cell stack 3a in which a plurality of cells 3 are stacked, and end plates 4 and 5 are disposed at both ends of the cell stack 3a in the stacking direction. The end plates 4 and 5 are connected by a tension plate 6.

  The end plate 5 has an end plate body 5a, and a stopper 7 is disposed on the end plate body 5a. A load adjusting screw 8 is screwed into the stopper 7, and the load adjusting screw 8 presses the cell stack 3 a in the stacking direction via a spring box 9.

JP 2007-173169 A

  In the above-mentioned Patent Document 1, the tension plate 6 connected between the end plates 4 and 5 is necessary to support the load in the stacking direction of the fuel cell stack 2. Moreover, a stack case 1 that covers the fuel cell stack 2 is separately required from the viewpoints of measures against water and dust when mounted on the vehicle body, impact resistance, and the like.

  For this reason, the fuel cell requires a large number of dedicated parts to satisfy each function, and the number of parts increases. As a result, the weight and cost of the entire fuel cell increase, and there are problems that the assembling work becomes complicated and the efficient assembling work cannot be performed.

  The present invention solves this type of problem, and with a simple and compact configuration, it can reliably apply an optimum tightening load in the stacking direction of the fuel cells and effectively protect the fuel cells from external load loads. An object of the present invention is to provide a fuel cell stack that can be used.

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 stacking direction of a stack in which a plurality of the fuel cells are stacked in a vertical direction The fuel cell stack is provided with first and second end plates at both ends.

The fuel cell stack includes a housing that accommodates the stacked body, and the housing is bent inward at one end on the first end plate side to engage with the first end plate, While providing the bending part which presses 1 end plate to the layered product side, the other end on the 2nd end plate side is provided with the connecting part combined with the 2nd end plate, and the rigidity of the case itself A tightening load is applied in the stacking direction of the stacked body, the first end plate is disposed above the stacked body, the second end plate is disposed below the stacked body, and the coupling portion is A plurality of bolts extending outward over the outer periphery, the flanges being in contact with the surface of the second end plate on the laminate side and having an axis in the lamination direction of the laminate More, is screwed to the second end plate, the end of the first end plate side of the housing has an opening for pressing the first end plate during assembly of the fuel cell stack Ru is formed.

  Further, in this fuel cell stack, a load measuring mechanism in which a plurality of load sensors are integrally connected to a connecting member is disposed between the first end plate and the laminated body, and the first end plate is also connected to the first end plate. Is preferably provided with a pressurizing mechanism for applying a fastening load to the laminate via the plurality of load sensors by pressing the load measuring mechanism toward the laminate.

Furthermore, the fuel cell stack includes a fuel 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, and a plurality of the fuel cells are stacked in a vertical direction. A fuel cell stack in which first and second end plates are disposed at both ends in the stacking direction of the stack, the housing including the stack, and the casing includes the first end plate One end on the side is bent inward and engaged with the first end plate, and provided with a bent portion that presses the first end plate toward the laminate, while the other end on the second end plate side, A coupling portion coupled to the second end plate is provided, the first end plate is disposed above the stacked body, the second end plate is disposed below the stacked body, and the coupling section is , Outside A flange extending outward, the flange being in contact with the surface of the second end plate on the laminate side, and a plurality of bolts having an axis in the stacking direction of the laminate. A load measuring mechanism in which a plurality of load sensors are integrally connected to a connecting member is disposed between the first end plate and the laminate, and is screwed to an end plate. The end plate is provided with a pressurizing mechanism for applying a fastening load to the laminate through the plurality of load sensors by pressing the load measuring mechanism toward the laminate, and the connecting member Is provided with a spherical recess at an outer position in plan view with respect to the position where the load sensor is disposed, and the tip of the load adjustment bolt provided on the first end plate is the spherical surface. Is disposed in the recess, said the center of said load adjusting bolt load sensor, characterized in that it misaligned with each other.

  According to the present invention, the housing that protects the fuel cell from an external environment such as an external load can also have a function of applying a load in the stacking direction to the stacked body. For this reason, compared with the case where a dedicated part is provided for each function, the number of parts is reduced favorably. Accordingly, it is possible to reliably apply an optimum tightening load in the stacking direction of the fuel cells with a simple and compact configuration, and to effectively protect the fuel cell from an external load load.

1 is a schematic perspective explanatory view of a fuel cell stack according to a first embodiment of the present invention. 2 is a cross-sectional side view of the fuel cell stack. FIG. FIG. 3 is an exploded perspective view of a main part of the fuel cell stack. FIG. 4 is a cross-sectional view of the fuel cell stack taken along line IV-IV in FIG. 3. It is a principal part disassembled perspective explanatory drawing of the fuel cell which comprises the said fuel cell stack. It is a cross-sectional explanatory drawing of the housing | casing which comprises the said fuel cell stack. It is principal part cross-sectional explanatory drawing of the fuel cell stack which concerns on the 2nd Embodiment of this invention. 2 is an explanatory diagram of a fuel cell of Patent Document 1. FIG.

  As shown in FIGS. 1 and 2, the fuel cell stack 10 according to the first embodiment of the present invention includes a stacked body 14 in which a plurality of fuel cells 12 are stacked in an arrow A direction (vertical direction).

  A first terminal plate 16a, a first insulating plate 18a, a load measuring mechanism 22 and a first end plate 20a are stacked on the upper end (one end) of the stacked body 14 in the stacking direction, and the first end plate 20a includes: A pressurizing mechanism 24 is provided (see FIGS. 1 to 4).

  A second terminal plate 16b, a second insulating plate 18b, and a second end plate 20b are stacked on the lower end (the other end) of the stacked body 14 in the stacking direction. The stacked body 14 may be configured by stacking a plurality of fuel cells 12 in the horizontal direction (arrow B direction or arrow C direction).

  As shown in FIG. 5, the fuel cell 12 includes an electrolyte membrane / electrode structure 30 sandwiched between first and second separators 32 and 34. The first and second separators 32 and 34 are constituted by, for example, a metal separator having a corrugated structure obtained by press-molding a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, a carbon separator, or the like.

  One end edge of the fuel cell 12 in the direction of arrow B (the horizontal direction in FIG. 5) communicates with each other in the direction of arrow A, which is the stacking direction, and oxidant for supplying an oxidant gas, for example, an oxygen-containing gas An agent gas inlet communication hole 36a and a fuel gas inlet communication hole 38a for supplying a fuel gas, for example, a hydrogen-containing gas, are arranged in an arrow C direction (horizontal direction).

  The other end edge of the fuel cell 12 in the direction of arrow B communicates with each other in the direction of arrow A, a fuel gas outlet communication hole 38b for discharging fuel gas, and an oxidant gas for discharging oxidant gas. The outlet communication holes 36b are arranged in the direction of arrow C.

  A cooling medium inlet communication hole 40a for supplying a cooling medium and a cooling medium outlet communication hole 40b for discharging the cooling medium are provided at both ends of the fuel cell 12 in the arrow C direction.

  An oxidant gas flow path 42 communicating with the oxidant gas inlet communication hole 36a and the oxidant gas outlet communication hole 36b is provided on the surface 32a of the first separator 32 facing the electrolyte membrane / electrode structure 30.

  A fuel gas passage 44 communicating with the fuel gas inlet communication hole 38a and the fuel gas outlet communication hole 38b is provided on the surface 34a of the second separator 34 facing the electrolyte membrane / electrode structure 30.

  A cooling medium that connects the cooling medium inlet communication hole 40a and the cooling medium outlet communication hole 40b between the surface 32b of the first separator 32 and the surface 34b of the second separator 34 that constitute the fuel cells 12 adjacent to each other. A flow path 46 is provided.

  A first seal member 48 is integrally or individually provided on the surfaces 32 a and 32 b of the first separator 32, and a second seal member 50 is integrally formed on the surfaces 34 a and 34 b of the second separator 34. Or it is provided separately.

  The first and second seal members 48 and 50 are, for example, EPDM, NBR, fluoro rubber, silicon rubber, fluorosilicon rubber, butyl rubber, natural rubber, styrene rubber, chloroprene, or acrylic rubber or the like, cushion material, Alternatively, a packing material is used.

  The electrolyte membrane / electrode structure 30 includes, for example, a solid polymer electrolyte membrane 52 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode side electrode 54 and an anode side electrode 56 that sandwich the solid polymer electrolyte membrane 52. With.

  The cathode side electrode 54 and the anode side electrode 56 are formed by uniformly applying a gas diffusion layer 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. An electrode catalyst layer. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 52.

  The second end plate 20b includes an oxidant gas inlet communication hole 36a, a fuel gas inlet communication hole 38a, a cooling medium inlet communication hole 40a, an oxidant gas outlet communication hole 36b, a fuel gas outlet communication hole 38b, and a cooling medium outlet communication hole. While a manifold (not shown) that communicates with 40b and extends to the outside is provided, the first end plate 20a is configured in a flat plate shape in which these and the seal member are omitted.

  As shown in FIGS. 3 and 4, the load measuring mechanism 22 includes a pressure plate 64 placed on the first insulating plate 18a. The pressure plate 64 has, for example, rectangular recesses 66 in the vicinity of the four corners. Is formed. The load measuring mechanism 22 includes a frame-shaped connecting member 68 and a load sensor, for example, a load cell 72 that is fixed to the four corners of the connecting member 68 via nuts 70.

  The connecting member 68 is provided with a spherical recess 74 having a spherical bottom surface in the vicinity of each load cell 72. Each load cell 72 is provided with a pressing member 76, and the pressing member 76 is disposed in each concave portion 66 of the pressing plate 64.

  The pressurizing mechanism 24 includes a plurality of, for example, four load adjustment bolts 78. Each load adjustment bolt 78 is screwed into a screw hole 80 formed in the first end plate 20 a, and each spherical tip 78 a is disposed in each spherical recess 74 of the connecting member 68. The center of each load adjustment bolt 78 and the center of each load cell 72 are displaced from each other. Since the load adjusting bolt 78 is provided, no spring member is required at the end in the stacking direction.

  As shown in FIGS. 1 and 2, the fuel cell stack 10 includes a casing 82 in which the stacked body 14 is accommodated. The casing 82 is made of, for example, an aluminum material, has a substantially rectangular tube shape, and is bent inward at one end 82a on the first end plate 20a side to be provided with a bent portion 84. The bent portion 84 is engaged with the outer peripheral edge of the first end plate 20a with a packing 86a interposed therebetween, and has a tightening load application function for pressing the first end plate 20a toward the laminated body 14 side.

  The other end 82b of the casing 82 on the second end plate 20b side forms a flange extending outward over the entire circumference to ensure the rigidity of the casing, and the second end plate is connected to the other end 82b. A coupling portion 88 coupled to 20b is provided. The coupling portion 88 includes a plurality of bolts 90 that screw the other end 82b and the second end plate 20b. In addition, while providing a hole in the other end 82b, you may form a screw hole in the 2nd end plate 20b.

  The second end plate 20b is formed with a stepped hole 92 for receiving the head of the bolt 90, while the other end 82b is screwed with the bolt 90 coaxially with the stepped hole 92. A screw hole 94 is formed. A packing 86b is interposed between the second end plate 20b and the other end 82b.

  As shown in FIG. 1, a load adjusting bolt 78 constituting the pressurizing mechanism 24 is exposed to the outside at one end 82a on the first end plate 20a side, and a stack pressing mechanism (not shown) is assembled during stack assembly to be described later. ) To form openings 96a and 96b for pressing the first end plate 20a. A reinforcing bridge 98 is integrally provided at one end 82a between the openings 96a and 96b.

  As shown in FIG. 6, on the inner surface of the housing 82, for example, two ribs 100a are vertically arranged on the inner surface 82l extending in the longitudinal direction (arrow B direction) of the first and second separators 32 and 34. It is provided extending in the direction. On the inner surface of the casing 82, for example, one rib 100b extends in the vertical direction on the inner surface 82s extending in the short direction (arrow C direction) of the first and second separators 32 and 34, respectively. .

  The ribs 100a and 100b ensure the rigidity of the casing 82. The ribs 100a and 100b further function as positioning guides for the outer circumferences of the first and second separators 32 and 34, and when the vehicle is given an impact from the outside, the first and second separators 32, 34 has a function of preventing deviation. An electrical insulator is preferably interposed between the ribs 100a and 100b and the outer peripheries of the first and second separators 32 and 34.

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

  First, as shown in FIG. 5, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 36a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 38a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 40a.

  Therefore, the oxidant gas is introduced into the oxidant gas flow path 42 of the first separator 32 from the oxidant gas inlet communication hole 36a. The oxidant gas is supplied to the cathode side electrode 54 constituting the electrolyte membrane / electrode structure 30 while moving in the arrow B direction.

  On the other hand, the fuel gas is introduced into the fuel gas flow path 44 of the second separator 34 from the fuel gas inlet communication hole 38a. The fuel gas is supplied to the anode side electrode 56 constituting the electrolyte membrane / electrode structure 30 while moving in the direction of arrow B.

  Therefore, in the electrolyte membrane / electrode structure 30, the oxidant gas supplied to the cathode side electrode 54 and the fuel gas supplied to the anode side electrode 56 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is done.

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 54 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 36b. On the other hand, the fuel gas consumed by being supplied to the anode side electrode 56 is discharged in the direction of arrow A along the fuel gas outlet communication hole 38b.

  The cooling medium supplied to the cooling medium inlet communication hole 40a is introduced into the cooling medium flow path 46 between the first and second separators 32 and 34, and then flows in the direction of arrow C. The cooling medium is discharged from the cooling medium outlet communication hole 40b after the electrolyte membrane / electrode structure 30 is cooled.

  By the way, when the fuel cell stack 10 is assembled, first, the plurality of fuel cells 12, that is, the stacked body 14 are disposed on the second end plate 20b via the second insulating plate 18b and the second terminal plate 16b. Are stacked. On the stacked body 14, the first terminal plate 16a, the first insulating plate 18a, the load measuring mechanism 22 and the first end plate 20a are stacked.

  Next, the first end plate 20a is pressed toward the second end plate 20b by a stack pressing mechanism (not shown) disposed corresponding to the openings 96a and 96b of the housing 82. Therefore, a load equal to or greater than the tightening load (lamination load) is applied to the laminate 14.

  In this state, one end 82a of the casing 82 contacts the outer peripheral edge of the first end plate 20a, while the other end 82b of the casing 82 is overlapped with the second end plate 20b. Then, the bolt 90 constituting the coupling portion 88 is inserted into the stepped hole portion 92 of the second end plate 20b and screwed into the screw hole 94 of the other end 82b. Therefore, the casing 82 is fixed to the second end plate 20b.

  Further, the stack pressing mechanism that presses the first end plate 20a is detached from the first end plate 20a. As a result, the outer peripheral edge of the first end plate 20a is pressed and held by the bent portion 84 of the casing 82, and the fuel cell stack 10 is assembled.

  Therefore, when the load adjusting bolt 78 constituting the pressurizing mechanism 24 is screwed into the screw hole 80 of the second end plate 20 b, the spherical tip portion 78 a of the load adjusting bolt 78 is the spherical concave portion 74 of the connecting member 68. Is pressed against the laminated body 14 side.

  For this reason, the load cell 72 attached to the connecting member 68 in the vicinity of the load adjusting bolt 78 presses the pressure plate 64 toward the laminated body 14 via the pressing member 76. As a result, a tightening load is applied to the laminate 14 via the pressure plate 64.

  By tightening each load adjustment bolt 78, each load cell 72 disposed in the vicinity of each load adjustment bolt 78 applies a tightening load to the laminate 14 via the pressure plate 64. Accordingly, each load cell 72 can accurately detect the value of the additional tightening load while applying the additional tightening load to the laminate 14.

  In addition, the total amount of the fastening load applied to the laminate 14 can be detected by the total value of the fastening loads detected from each load cell 72, and highly accurate tightening processing is performed with a simple configuration. .

  In this case, in the first embodiment, the casing 82 that protects the fuel cell 12 from an external environment such as an external load can also have a function of applying a load in the stacking direction to the stacked body 14. For this reason, compared with the case where exclusive parts, for example, fastening parts, such as a tie rod and a tension plate, are provided for every function, the number of parts is reduced favorably.

  Thereby, it is possible to reliably apply an optimum tightening load in the stacking direction of the fuel cells 12 with a simple and compact configuration, and to effectively protect the fuel cells 12 from external load loads. Is obtained.

  FIG. 7 is an explanatory cross-sectional view of a main part of a fuel cell stack 110 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.

  A pressurizing mechanism 112 is provided on the first end plate 20 a constituting the fuel cell stack 110. The pressurizing mechanism 112 includes a plurality of coil springs (may be disc springs) 114 interposed between the first end plate 20 a and the connecting member 68. In the second embodiment configured as described above, the same effect as in the first embodiment can be obtained.

DESCRIPTION OF SYMBOLS 10,110 ... Fuel cell stack 12 ... Fuel cell 14 ... Laminated body 16a, 16b ... Terminal plate 18a, 18b ... Insulating plate 20a, 20b ... End plate 22 ... Load measuring mechanism 24, 112 ... Pressurizing mechanism 30 ... Electrolyte membrane Electrode structure 32, 34 ... Separator 36a ... Oxidant gas inlet communication hole 36b ... Oxidant gas outlet communication hole 38a ... Fuel gas inlet communication hole 38b ... Fuel gas outlet communication hole 40a ... Cooling medium inlet communication hole 40b ... Cooling medium outlet Communication hole 42 ... Oxidant gas flow path 44 ... Fuel gas flow path 46 ... Cooling medium flow path 52 ... Solid polymer electrolyte membrane 54 ... Cathode side electrode 56 ... Anode side electrode 82 ... Housing 82a ... One end 82b ... Other end 84 ... Bending part 86a, 86b ... Packing 88 ... Coupling part 90 ... Bolt 100a, 100b ... Rib

Claims (3)

Provided with 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 fuel cells stacked in the vertical direction at both ends in the stacking direction, A fuel cell stack in which first and second end plates are disposed,
A housing for accommodating the laminate,
The casing is provided with a bent portion at one end on the first end plate side that is bent inward to engage with the first end plate and presses the first end plate toward the laminate,
A coupling portion coupled to the second end plate is provided at the other end on the second end plate side,
Due to the rigidity of the casing itself, a clamping load is applied in the stacking direction of the laminate,
The first end plate is disposed above the laminate,
The second end plate is disposed below the laminate,
The coupling portion has a flange extending outward over the outer periphery;
The flange is screwed to the second end plate by a plurality of bolts that are in contact with the surface of the second end plate on the laminate side and have an axis in the stacking direction of the laminate .
The fuel cell stack is characterized in that an opening for pressing the first end plate is formed at the one end of the housing on the first end plate side when the fuel cell stack is assembled . The fuel cell stack according to claim 1, wherein a load measuring mechanism in which a plurality of load sensors are integrally connected to a connecting member is disposed between the first end plate and the stacked body.
The first end plate is provided with a pressure mechanism for applying a fastening load to the stacked body via the plurality of load sensors by pressing the load measuring mechanism toward the stacked body. A fuel cell stack characterized by Provided with 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 fuel cells stacked in the vertical direction at both ends in the stacking direction, A fuel cell stack in which first and second end plates are disposed,
A housing for accommodating the laminate,
The casing is provided with a bent portion at one end on the first end plate side that is bent inward to engage with the first end plate and presses the first end plate toward the laminate,
A coupling portion coupled to the second end plate is provided at the other end on the second end plate side,
The first end plate is disposed above the laminate,
The second end plate is disposed below the laminate,
The coupling portion has a flange extending outward over the outer periphery;
The flange is screwed to the second end plate by a plurality of bolts that are in contact with the surface of the second end plate on the laminate side and have an axis in the stacking direction of the laminate.
Between the first end plate and the laminate, a load measuring mechanism in which a plurality of load sensors are integrally connected to a connecting member is disposed,
The first end plate is provided with a pressurizing mechanism for applying a fastening load to the laminate via the plurality of load sensors by pressing the load measuring mechanism toward the laminate.
The connecting member includes a spherical recess at an outer position in plan view with respect to a position where the load sensor is disposed,
A tip end portion of a load adjusting bolt provided on the first end plate is disposed in the spherical recess,
The fuel cell stack, wherein the center of the load sensor and the center of the load adjustment bolt are displaced from each other.

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