JP2012054125A - Fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To excellently inhibit heat dissipation from a terminal plate to prevent fuel cells, especially at the ends of the lamination, from decreasing in power generating capacity to the extent possible.SOLUTION: In a fuel cell stack 10, a plurality of fuel cells 12 is laminated, and a terminal plate 14a, an insulation plate 16a, and an end plate 18a are disposed at one end of the lamination of the fuel cells 12. The terminal plate 14a contains a single internal cavity 52a. The cavity 52a extends through the terminal plate 14a from one end to the other end of the terminal plate 14a facing each other. The center of a plate face 54a of the terminal plate 14a facing the insulation plate 16a is provided with a connecting terminal 56a projecting outward in the lamination direction and exposed at the end plate 18a.

Description

  The present invention provides 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 includes a stacked body in which a plurality of the fuel cells are stacked. The present invention relates to a fuel cell stack in which a terminal plate, an insulating plate, and an end plate are stacked at both ends of the body 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 provided by a pair of separators. The power generation unit is sandwiched. This type of fuel cell is usually used as, for example, an in-vehicle fuel cell stack by stacking a predetermined number (for example, several hundreds) of power generation units.

  The fuel cell stack includes a stacked body in which a plurality of power generation units are stacked, and a terminal plate, an insulating plate, and an end plate are stacked at both ends in the stacking direction of the stacked body. At that time, since the terminal plate and the end plate have a large amount of heat radiation, the temperature of the power generation units arranged at both ends in the stacking direction of the laminate is likely to decrease, and the power generation performance of the power generation unit is deteriorated. is there.

  Therefore, for example, a polymer electrolyte fuel cell stack disclosed in Patent Document 1 is known. This polymer electrolyte fuel cell stack is configured by laminating a plurality of power generation units in which a solid polymer electrolyte membrane is sandwiched between a pair of electrodes and the outside is sandwiched between a pair of separators in the horizontal direction. And the heat insulation layer is interposed between the electric power generation unit located in the at least one edge part of the lamination direction, and the terminal plate arrange | positioned on the outer side.

JP 2002-184449 A

  By the way, in the polymer electrolyte fuel cell stack described above, a heat insulating layer is provided between the power generation unit at the end in the stacking direction and the terminal plate, but heat radiation is likely to be caused from the terminal plate itself. In particular, the amount of heat released from the terminal portion (connection terminal) for power extraction protruding from the terminal plate in the stacking direction increases. As a result, the temperature at the stack end decreases, and the power generation performance of the power generation unit at the end in the stacking direction may decrease.

  The present invention solves this type of problem, and can effectively suppress the heat radiation from the terminal plate, and in particular prevents the deterioration of the power generation performance of the fuel cell disposed at the end in the stacking direction. An object of the present invention is to provide a fuel cell stack that can be used.

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

  In this fuel cell stack, the terminal plate has a single space inside, and a connection terminal that protrudes outward in the stacking direction and is exposed from the end plate is provided at the center of the plate surface facing the insulating plate. It has been.

  Moreover, in this fuel cell stack, it is preferable that the space portion penetrates the terminal plate from one end portion to the other end portion of the terminal plate.

  Further, in this fuel cell stack, it is preferable that the connection terminal is formed by cutting out the plate surface leaving one end on the short side of the rectangular shape and then bending it in the stacking direction.

  Furthermore, in this fuel cell stack, it is preferable that a block member is disposed in the space portion.

  According to the present invention, since the space portion is formed inside the terminal plate, the space portion functions as a heat insulating layer. Therefore, heat dissipation from the terminal plate can be satisfactorily suppressed.

  Moreover, the terminal plate is provided with a connection terminal at the center of the plate surface so as to protrude outward in the stacking direction. For this reason, the heat transfer path from the fuel cell arranged at the end in the stacking direction to the connection terminal is lengthened, and heat radiation from the connection terminal is effectively suppressed. Thereby, especially the fuel cell arrange | positioned at the lamination direction edge part can prevent the fall of the power generation performance by a temperature fall as much as possible.

1 is a perspective explanatory view of a fuel cell stack according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of the fuel cell stack taken along line II-II in FIG. 1. It is a principal part disassembled perspective explanatory drawing of the fuel cell which comprises the said fuel cell stack. It is a perspective view of a terminal plate constituting the fuel cell stack. It is explanatory drawing of the heat path by the said terminal plate. It is side surface explanatory drawing of the terminal plate which comprises the fuel cell stack which concerns on the 2nd Embodiment of this invention. It is a perspective explanatory view of a terminal plate which constitutes a fuel cell stack concerning a 3rd embodiment of the present invention.

  As shown in FIGS. 1 and 2, the fuel cell stack 10 according to the first embodiment of the present invention has a plurality of fuel cells (power generation units) 12 stacked in the direction of arrow A (horizontal direction or vertical direction). A laminate 13 is provided.

  A terminal plate 14a, an insulating plate 16a, and an end plate 18a are disposed at one end of the stacked body 13 in the stacking direction. A terminal plate 14b, an insulating plate 16b, and an end plate 18b are disposed at the other end of the stacked body 13 in the stacking direction.

  As shown in FIGS. 2 and 3, in the fuel cell 12, an electrolyte membrane / electrode structure (MEA) 20 is sandwiched between first and second separators 22 and 24. The first and second separators 22 and 24 are made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a vertically long metal plate that has been subjected to a surface treatment for anticorrosion on its metal surface. The first and second separators 22 and 24 have a rectangular planar shape, and are formed into a concavo-convex shape by pressing a metal thin plate into a wave shape. In addition, you may comprise the 1st and 2nd separators 22 and 24 with a carbon separator, for example.

  At the upper edge of the fuel cell 12 in the direction of arrow C (vertical direction in FIG. 3), an oxidant for supplying an oxidant gas, for example, an oxygen-containing gas, communicates with each other in the direction of arrow A, which is the stacking direction. An agent gas inlet communication hole 26a, a cooling medium inlet communication hole 28a for supplying a cooling medium, and a fuel gas inlet communication hole 30a for supplying a fuel gas, for example, a hydrogen-containing gas, are arranged in the arrow B direction. Provided.

  The lower end edge of the fuel cell 12 in the direction of arrow C communicates with each other in the direction of arrow A, a fuel gas outlet communication hole 30b for discharging fuel gas, and a cooling medium outlet communication hole 28b for discharging cooling medium. , And oxidant gas outlet communication holes 26b for discharging the oxidant gas are arranged in the arrow B 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 formed on the surface 22a of the first separator 22 facing the electrolyte membrane / electrode structure 20 along the vertical direction. Provided.

  A fuel gas channel 34 communicating with the fuel gas inlet communication hole 30a and the fuel gas outlet communication hole 30b is provided along the vertical direction 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 28a and the cooling medium outlet communication hole 28b 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 along the vertical direction.

  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. 2, recesses 48a and 48b are formed in the insulating plates 16a and 16b, and the terminal plates 14a and 14b are accommodated in the recesses 48a and 48b.

  As shown in FIGS. 2 and 4, the terminal plate 14a is made of a conductive metal material, such as aluminum or copper, and has a single space 52a inside. The space 52a penetrates the terminal plate 14a from one end of the terminal plate 14a facing each other toward the other end (in the direction of arrow C in FIG. 4). The terminal plate 14a has a rectangular tube shape.

  A connection terminal (power extraction terminal) 56a that protrudes outward in the stacking direction (arrow A direction) and is exposed from the end plate 18a is provided at the center of the plate surface 54a facing the insulating plate 16a of the terminal plate 14a.

  The connection terminal 56a has a columnar shape, is fixed to the plate surface 54a by friction stir welding (FSW), friction welding (FW), or the like, and is inserted into the end plate 18a with the insulating cylinder 58a mounted on the exterior. The connection terminal 56a can be set in various shapes such as a prismatic shape and an L shape.

  Further, the terminal plate 14b is configured in the same manner as the terminal plate 14a described above, and the same components are denoted by the same reference numerals with b instead of a, and detailed description thereof is omitted.

  As shown in FIG. 1, a plurality of connecting members 60 are bridged between the end plate 18a and the end plate 18b. The connecting members 60 have a long plate shape, and two connecting members 60 are disposed on the long side of the fuel cell stack 10 and one on the short side of the fuel cell stack 10. Both ends of the connecting member 60 in the direction of arrow A are fixed to the side portions of the end plate 18a and the end plate 18b via bolts 62, and a predetermined tightening load is applied between the end plates 18a and 18b in the stacking direction. Is done.

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

  First, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 26a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 30a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 28a.

  For this reason, as shown in FIG. 3, 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 downward in the direction of arrow C.

  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 30a. The fuel gas is supplied to the anode side electrode 46 constituting the electrolyte membrane / electrode structure 20 while moving downward in the arrow C 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. The fuel cells 12 are electrically connected in series, and electric power is taken out from the connection terminals 56a and 56b provided on the terminal plates 14a and 14b disposed at both ends of the fuel cells 12 in the stacking direction. For example, a travel motor (not shown) is driven.

  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 30b.

  The cooling medium supplied to the cooling medium inlet communication hole 28a is introduced into the cooling medium flow path 36 between the first and second separators 22 and 24, and flows downward in the direction of arrow C. The cooling medium cools the electrolyte membrane / electrode structure 20 and then is discharged to the cooling medium outlet communication hole 28b.

  In this case, in the first embodiment, as shown in FIGS. 2 and 4, a space 52a is formed inside the terminal plate 14a. Therefore, in the terminal plate 14a, the space part 52a can function as a heat insulation layer, and it becomes possible to suppress the heat radiation from the terminal plate 14a satisfactorily.

  In addition, the plate surface 54a of the terminal plate 14a facing the insulating plate 16a is provided with a connection terminal 56a that protrudes outward in the stacking direction at the center. For this reason, as shown in FIG. 5, the heat transfer path (heat path) from the fuel cell 12 disposed at the end of the stacked body 13 to the connection terminal 56a is considerably elongated.

  As a result, heat dissipation from the connection terminal 56a is effectively suppressed, and particularly the fuel cell 12 disposed at the end portion in the stacking direction can prevent a decrease in power generation performance due to a temperature decrease as much as possible. Is obtained.

  Further, in the terminal plate 14a, the space 52a penetrates from one end of the terminal plate 14a facing each other toward the other end (in the direction of arrow C in FIG. 4). It has a cylindrical shape.

  Therefore, the terminal plate 14a can produce the space part 52a by extrusion molding or pultrusion molding, and it is advantageous that the processing cost of the terminal plate 14a is reduced well and is economical.

  FIG. 6 is an explanatory side view of the terminal plate 100 constituting the fuel cell stack according to the second embodiment of the present invention.

  Note that the same components as those of the terminal plate 14a constituting 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 embodiment described below, detailed description thereof is omitted.

  A space 102 is formed in the terminal plate 100, and the terminal plate 100 has a rectangular tube shape. At the center of the plate surface 104 facing the insulating plate 16a of the terminal plate 100, a connection terminal (power extraction terminal) 106 that protrudes outward in the stacking direction (arrow A direction) and is exposed from the end plate 18a is provided.

  Block members 108 a and 108 b having a function of backing the connection terminals 106 are disposed in the space 102 of the terminal plate 100. Positioning guides 110 a and 110 b and positioning guides 112 a and 112 b are formed on the terminal plate 100 so as to protrude into the space 102.

  The positioning guides 110a, 110b, 112a, and 112b are integrally formed when the terminal plate 100 is extruded, for example. The positioning guides 110a and 110b position the block member 108a, while the positioning guides 112a and 112b position the block member 108b. The block member 108a is made of a material having low thermal conductivity, such as a polymer material.

  In the second embodiment configured as described above, the same effects as those of the first embodiment described above can be obtained, and the block members 108a and 108b are arranged as the backing members of the connection terminal 106. It becomes possible to hold the terminal 106 more firmly.

  FIG. 7 is a perspective explanatory view of a terminal plate 120 constituting a fuel cell stack according to the third embodiment of the present invention.

  A space 124 is formed in the terminal plate 120, and the terminal plate 120 has a rectangular tube shape. A connection terminal (power extraction terminal) 128 that protrudes outward in the stacking direction (in the direction of arrow A) and is exposed from the end plate 18a is provided at the center of the plate surface 126 facing the insulating plate 16a of the terminal plate 120.

  The connection terminal 128 is formed by cutting out the plate surface 126 except for one end on the short side of the rectangular shape and then bending it in the stacking direction. In the plate surface 126, an opening 130 corresponding to the shape of the connection terminal 128 is formed.

  Although not shown, a block member for receiving the connection terminal 128 is disposed in the space 124 of the terminal plate 120 as necessary, as in the second embodiment. The terminal plate 120 preferably has a positioning guide (not shown) that protrudes into the space 124.

  In the third embodiment configured as described above, the same effects as those of the first and second embodiments can be obtained.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 12 ... Fuel cell 13 ... Laminated body 14a, 14b, 100, 120 ... Terminal plate 16a, 16b ... Insulating plate 18a, 18b ... End plate 20 ... Electrolyte membrane and electrode structure 22, 24 ... Separator 26a ... Oxidant gas inlet communication hole 26b ... Oxidant gas outlet communication hole 28a ... Cooling medium inlet communication hole 28b ... Cooling medium outlet communication hole 30a ... Fuel gas inlet communication hole 30b ... Fuel gas 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 electrodes 52a, 102, 124 ... Space portions 54a, 104, 126 ... Plate surfaces 56a, 106, 128 ... Connection terminal 60 ... connecting member 108a, 108b ... block member
110a, 110b, 112a, 112b ... positioning guide 130 ... opening

Claims (4)

Provided is 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 includes a stack in which a plurality of the fuel cells are stacked, and the stacking direction of the stack A fuel cell stack in which a terminal plate, an insulating plate and an end plate are laminated at both ends,
The terminal plate has a single space inside, and
A fuel cell stack, wherein a connection terminal that protrudes outward in the stacking direction and is exposed from the end plate is provided at a central portion of the plate surface facing the insulating plate.   2. The fuel cell stack according to claim 1, wherein the space portion passes through the terminal plate from one end portion to the other end portion of the terminal plate facing each other.   3. The fuel cell stack according to claim 1, wherein the connection terminal is formed by bending the plate surface in the stacking direction after notching one end of a rectangular short side. A fuel cell stack.   4. The fuel cell stack according to claim 1, wherein a block member is disposed in the space portion. 5.

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