JP5378049B2 - Fuel cell stack - Google Patents

Description

  The present invention relates to a fuel cell stack in which a plurality of fuel cells are stacked and a terminal plate, an insulating plate, and an end plate are disposed at both ends in the stacking direction.

  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. A unit cell is provided. This type of fuel cell is normally used as a 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, the fuel cell stack disclosed in Patent Document 1 includes a fuel cell assembly 1 in which a plurality of fuel cells are stacked in the vertical direction, as shown in FIG. A pair of terminal plates 2, a pair of spacer plates 3, and end plates 4, 5 are disposed at both upper and lower ends of the fuel cell assembly 1.

  The space between the end plates 4 and 5 is fixed to the side plate 6 by screws, so that the space between the end plates 4 and 5 is maintained. A desired tightening load is applied to the fuel cell assembly 1 by using one or a plurality of spacer plates 3.

US Pat. No. 7,045,245

  However, in Patent Document 1 described above, the spacer plate 3 is made of a resin material because it needs to have an insulating function, and the spacer plate 3 cannot be made thin. For example, in a thin resin plate of 0.1 mm to 0.5 mm or the like, a seal groove cannot be provided around the through hole. Therefore, there is a problem that the fuel cell stack cannot be shortened in the stacking direction.

  The present invention solves this type of problem, and has an object to provide a fuel cell stack capable of adjusting a stacking load with high accuracy using a thin spacer with a simple and compact configuration. To do.

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 the plurality of fuel cells are stacked in the direction of gravity and the stacking direction is lower At the end, towards the stacking direction downward, sequentially, a first terminal plate, while the first insulating plate and the first end plate are stacked, the stacking direction on the end is toward the stacking direction upwards, successively, the The present invention relates to a fuel cell stack in which a two-terminal plate, a second insulating plate, and a second end plate are stacked.

  The first end plate includes a reaction gas supply unit that supplies a reaction gas along a stacking direction, a reaction gas discharge unit that discharges the reaction gas, a refrigerant body supply unit that supplies a refrigerant body, and a cold that discharges the refrigerant body. A medium discharge portion is formed.

A flat spacer for adjusting the stacking load is interposed between the second end plate and the second insulating plate in contact with the second end plate, and at least the second end plate. The flat spacer and the second insulating plate do not have a reaction gas supply unit, a reaction gas discharge unit, a refrigerant supply unit, and a refrigerant discharge unit.

  Furthermore, the flat spacer is preferably made of a metal material or a carbon material.

  According to the present invention, a sealing structure for sealing the reaction gas and the cooling medium to the flat spacer is not necessary, and the configuration of the flat spacer is simplified at a time. In addition, the flat spacer does not need to consider insulation, and can be made of various materials such as a metal material and a carbon material in addition to a resin material. Thereby, if the flat spacer is made of, for example, a metal thin plate, fine spacing adjustment can be easily performed with high accuracy, and versatility can be improved.

1 is a schematic perspective explanatory view of a fuel cell stack according to a first embodiment of the present invention. It is a principal part disassembled perspective explanatory drawing of the fuel cell which comprises the said fuel cell stack. FIG. 3 is an exploded perspective view of a main part of the fuel cell stack. It is principal part sectional drawing of the said fuel cell stack. It is a principal part disassembled perspective explanatory drawing of the fuel cell stack which concerns on the 2nd Embodiment of this invention. 6 is a cross-sectional explanatory view of a fuel cell stack of Patent Document 1. FIG.

  As shown in FIG. 1, in the fuel cell stack 10 according to the first embodiment of the present invention, a plurality of fuel cells 12 are stacked in the direction of arrow A (vertical direction). The first terminal plate 14a, the first insulating plate 16a and the first end plate 18a are stacked at the lower end (one end) of the fuel cell 12 in the stacking direction, while the second terminal plate is stacked at the upper end (the other end) of the stacking direction. 14b, the second insulating plate 16b and the second end plate 18b are laminated.

  As shown in FIG. 2, the fuel cell 12 includes an electrolyte membrane / electrode structure 20 sandwiched between first and second separators 22 and 24. The first and second separators 22 and 24 are made of, for example, a metal separator such as a steel plate, a stainless steel plate, an aluminum plate, or a plated steel plate, or a carbon separator.

  One end edge of the fuel cell 12 in the direction of arrow B (the horizontal direction in FIG. 2) 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 26a and a fuel gas inlet communication hole 28a 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, the fuel gas outlet communication hole 28b for discharging the fuel gas, and the oxidant gas for discharging the oxidant gas. Outlet communication holes 26b are arranged in the direction of arrow C.

  A cooling medium inlet communication hole 30a for supplying a cooling medium and a cooling medium outlet communication hole 30b 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 32 communicating with the oxidant gas inlet communication hole 26a and the oxidant gas outlet communication hole 26b is provided on the surface 22a of the first separator 22 facing the electrolyte membrane / electrode structure 20.

  A fuel gas passage 34 communicating with the fuel gas inlet communication hole 28a and the fuel gas outlet communication hole 28b is provided on the surface 24a of the second separator 24 facing the electrolyte membrane / electrode structure 20.

  A cooling medium that connects the cooling medium inlet communication hole 30a and the cooling medium outlet communication hole 30b between the surface 22b of the first separator 22 and the surface 24b of the second separator 24 that constitute the fuel cells 12 adjacent to each other. A flow path 36 is provided.

  The first seal member 38 is integrally or individually provided on the surfaces 22 a and 22 b of the first separator 22, and the second seal member 40 is integrally formed on the surfaces 24 a and 24 b of the second separator 24. Or it is provided separately.

  The first and second sealing members 38 and 40 are, for example, EPDM, NBR, fluorine rubber, silicon rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene, or acrylic rubber or the like, cushioning material, Alternatively, a packing material is used.

  The electrolyte membrane / electrode structure 20 includes, for example, a solid polymer electrolyte membrane 42 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode side electrode 44 and an anode side electrode 46 that sandwich the solid polymer electrolyte membrane 42. With.

  The cathode side electrode 44 and the anode side electrode 46 are formed by uniformly applying a gas diffusion layer made of carbon paper or the like and porous carbon particles having a platinum alloy supported 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 42.

  As shown in FIG. 1, for example, a plurality of connecting members 50 are bridged between the first and second end plates 18a, 18b made of aluminum, and between the first and second end plates 18a, 18b. The distance is kept constant. The connecting member 50 has, for example, a long plate shape made of aluminum, and two connecting members 50 are arranged on the long side of the fuel cell stack 10 and one on the short side of the fuel cell stack 10. Is done. The connecting member 50 is fixed to the side portions of the first and second end plates 18a and 18b via screws 52.

  The first end plate 18a includes an oxidant gas inlet communication hole (reactive gas supply part) 26a, a fuel gas inlet communication hole (reactive gas supply part) 28a, a cooling medium inlet communication hole (refrigerant supply part) 30a, an oxidant. A manifold (not shown) that communicates with the gas outlet communication hole (reactive gas discharge part) 26b, the fuel gas outlet communication hole (reactive gas discharge part) 28b, and the cooling medium outlet communication hole (refrigerant discharge part) 30b and extends to the outside. 2), the second end plate 18b is formed in a flat plate shape from which these and the seal member are omitted.

  As shown in FIG. 3, the second terminal plate 14 b is provided with a rod-shaped power extraction terminal 54 protruding upward in the stacking direction (gravity direction) at a desired position. A screw hole 55 is formed in the axial direction at the tip of the power extraction terminal 54.

  As shown in FIGS. 3 and 4, the second insulating plate 16 b is provided with a cylindrical portion 56 that goes around the power extraction terminal 54 and protrudes upward in the stacking direction. The tubular portion 56 is fitted into a hole 58 formed in the second end plate 18b, and the second end plate 18b is bulged radially inward at the upper end side of the hole 58. A portion 60 is provided.

  One end of a conductive plate 64 is fixed to the power extraction terminal 54 via a screw 62, and the other end of the conductive plate 64 protrudes to the side of the second end plate 18b and is connected to a cable (not shown). The

  A cover member 66 is provided to surround the conductive plate 64 and the power extraction terminal 54. The cover member 66 has a cylindrical portion 68 that is slidably fitted to the inner peripheral surface of the cylindrical portion 56 of the second insulating plate 16b via a seal 67. The cylindrical portion 68 is press-fitted into the convex portion 60 of the second end plate 18 b and fixed to the convex portion 60.

  The first terminal plate 14a, the first insulating plate 16a, and the first end plate 18a are also configured in the same manner as described above, and detailed description thereof is omitted.

  As shown in FIG. 3, the second insulating plate 16b includes an oxidant gas inlet communication hole 26a, a fuel gas inlet communication hole 28a, a cooling medium inlet communication hole 30a, an oxidant gas outlet communication hole 26b, and a fuel gas outlet communication hole 28b. In addition, it is configured in a flat plate shape in which the cooling medium outlet communication hole 30 b is omitted, and only a cylindrical portion 56 that circulates around the power extraction terminal 54 is provided.

  Between the second end plate 18b and the second insulating plate 16b, a predetermined number of flat spacers 70 for adjusting the stacking load are stacked. The flat spacer 70 is made of a rectangular plate material, and is provided with only a hole 72 for inserting the cylindrical portion 56 of the second insulating plate 16b. The flat spacer 70 is made of a metal material or a carbon material in addition to a resin material.

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

  First, as shown in FIG. 2, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 26a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 28a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 30a.

  Therefore, the oxidant gas is introduced into the oxidant gas flow path 32 of the first separator 22 from the oxidant gas inlet communication hole 26a. The oxidant gas is supplied to the cathode side electrode 44 constituting the electrolyte membrane / electrode structure 20 while moving in the arrow B direction.

  On the other hand, the fuel gas is introduced into the fuel gas flow path 34 of the second separator 24 from the fuel gas inlet communication hole 28a. The fuel gas is supplied to the anode side electrode 46 constituting the electrolyte membrane / electrode structure 20 while moving in the arrow B direction.

  Therefore, in the electrolyte membrane / electrode structure 20, the oxidant gas supplied to the cathode side electrode 44 and the fuel gas supplied to the anode side electrode 46 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 44 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 26b. On the other hand, the fuel gas consumed by being supplied to the anode electrode 46 is discharged in the direction of arrow A along the fuel gas outlet communication hole 28b.

  The cooling medium supplied to the cooling medium inlet communication hole 30a is introduced into the cooling medium flow path 36 between the first and second separators 22 and 24 and then flows in the direction of arrow C. After cooling the electrolyte membrane / electrode structure 20, the cooling medium is discharged from the cooling medium outlet communication hole 30b.

  In this case, in the first embodiment, manifolds for circulating the oxidant gas, the fuel gas, and the cooling medium are concentrated on the first end plate 18a side, and the second end plate 18b side, Specifically, it is not necessary to circulate oxidant gas, fuel gas, and cooling medium through the second insulating plate 16b, the flat spacer 70, and the second end plate 18b.

  Accordingly, the plurality of flat plate spacers 70 for adjusting the stacking load interposed between the second insulating plate 16b and the second end plate 18b are seals for sealing the oxidant gas, the fuel gas, and the cooling medium. No structure is required. For this reason, the structure of the flat spacer 70 is simplified at a stroke, and it is only necessary to provide only the hole portion 72 that does not need to be sealed, and the manufacturing cost of the flat spacer 70 can be greatly reduced. .

  In addition, since the flat spacer 70 is interposed between the second insulating plate 16b and the second end plate 18b, there is no need to consider insulation, and in addition to a resin material, a metal material, a carbon material, etc. It can be composed of various materials. As a result, the flat spacer 70 is formed of a metal thin plate, for example, so that the thickness can be considerably reduced as compared with the resin material, and the fine interval adjustment can be easily performed with high accuracy. is there.

  Further, the flat spacer 70 can be made of various materials, and is improved in versatility and economical.

  FIG. 5 is an exploded perspective view of a main part of a fuel cell stack 80 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.

  The second terminal plate 14b constituting the fuel cell stack 80 protrudes outward in the surface direction on one side surface and is provided with a plate-shaped power extraction terminal 82. The second insulating plate 16b and the second end plate 18b are configured in a closed plate shape in which the communication hole, the seal structure, and the hole are omitted.

  Similarly, the predetermined number of flat plate spacers 84 interposed between the second insulating plate 16b and the second end plate 18b are configured in a closed plate shape in which the communication hole, the seal structure, and the hole portion are omitted. The

  In the second embodiment configured as described above, the same effects as those of the first embodiment can be obtained, and the flat spacer 84 does not need to be provided with any hole or the like. Thereby, the structure of the said flat spacer 84 is simplified further, and the advantage that it is economical is acquired.

  In the first and second embodiments, the fuel cell stacks 10 and 80 have a plurality of fuel cells 12 stacked in the direction of gravity. Instead, the fuel cells 12 are stacked in the horizontal direction. May be configured.

DESCRIPTION OF SYMBOLS 10,80 ... Fuel cell stack 12 ... Fuel cell 14a, 14b ... Terminal plate 16a, 16b ... Insulation plate 18a, 18b ... End plate 20 ... Electrolyte membrane electrode structure 22, 24 ... Separator 26a ... Oxidant gas inlet communication hole 26b ... Oxidant gas outlet communication hole 28a ... Fuel gas inlet communication hole 28b ... Fuel gas outlet communication hole 30a ... Cooling medium inlet communication hole 30b ... Cooling medium outlet communication hole 32 ... Oxidant gas flow path 34 ... Fuel gas flow path 36 ... Cooling medium flow path 42 ... Solid polymer electrolyte membrane 44 ... Cathode side electrode 46 ... Anode side electrode 50 ... Connecting members 54, 82 ... Power extraction terminals 56 ... Cylindrical parts 58, 72 ... Hole parts 66 ... Cover member 70, 84 ... Flat spacer

Claims (2)

Comprising a fuel cell and a separator and the membrane electrode assembly in which a pair of electrodes on both sides of the electrolyte membrane is laminated, a plurality of the fuel cells are stacked in the direction of gravity, in the stacking direction under end, toward a stacking direction downward, sequentially, a first terminal plate, while the first insulating plate and the first end plate are stacked, the stacking direction on the end is toward the stacking direction upwards, successively, a second terminal plate, A fuel cell stack in which a second insulating plate and a second end plate are stacked,
The first end plate has a reaction gas supply unit that supplies a reaction gas along the stacking direction, a reaction gas discharge unit that discharges the reaction gas, a refrigerant supply unit that supplies a refrigerant body, and a discharge of the refrigerant body A refrigerant discharge part is formed,
Between the second end plate and the second insulating plate, a flat spacer for adjusting the stacking load is interposed in contact with the second end plate ,
At least the second end plate, the flat spacer, and the second insulating plate do not have the reaction gas supply unit, the reaction gas discharge unit, the refrigerant supply unit, and the refrigerant discharge unit. Fuel cell stack. The fuel cell stack according to claim 1 Symbol placement, the flat spacers, fuel cell stack, characterized in that it is formed of a metal material or carbon material.

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