JP5021698B2 - Fuel cell stack - Google Patents

Description

  The present invention relates to a fuel cell stack including a fuel cell unit that sandwiches at least first and second electrolyte / electrode structures provided with a pair of electrodes on both sides of an electrolyte between at least first to third separators. .

  For example, a polymer electrolyte fuel cell is an electrolyte membrane / electrode structure in which an anode side electrode and a cathode side electrode are respectively provided on both sides of a solid polymer electrolyte membrane made of a polymer ion exchange membrane (cation exchange membrane). The (electrolyte / electrode structure) is sandwiched between separators to constitute a unit cell.

  In this unit 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 the electrode catalyst, and the cathode passes through the 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, the fuel cell normally forms a stack by stacking several tens to several hundreds of unit cells. At that time, it is necessary to accurately position each unit cell, and therefore, an operation of inserting a knock pin into a positioning hole formed in the unit cell is performed. However, as the number of stacked unit cells increases, the operation of inserting the knock pin becomes difficult, the workability is lowered, the position of the member is easily displaced, and the sealing function is lowered. .

  Therefore, in order to solve the above problem, Patent Document 1 discloses a fuel cell configured by sandwiching an electrolyte / electrode structure provided with a pair of electrodes on both sides of an electrolyte between first and second separators. The first and second separators are provided with first and second positioning holes, and first and second insulating positioning members are mounted in the first and second positioning holes. The first and second separators are positioned in an insulated state by fitting the outer peripheral wall portion of the second insulating positioning member to the inner peripheral wall portion of the first insulating positioning member. A fuel cell is disclosed.

  Further, the first insulating positioning member is fitted to the support portion for supporting one surface of the first separator and the first positioning hole portion of the first separator, and the bulging portion is provided with the inner peripheral wall portion. The second insulating positioning member includes a support portion that supports one surface of the second separator, a first bulging portion that fits into a second positioning hole portion of the second separator, and the first A second bulging portion is provided that protrudes to the opposite side of the first bulging portion and is provided with an outer peripheral wall portion.

JP 2004-172094 A (FIG. 3)

  The above-mentioned Patent Document 1 relates to a structure for positioning the first and second separators in a fuel cell (unit cell) in which an electrolyte / electrode structure is sandwiched between first and second separators.

  Recently, however, a so-called thinning-out cooling type fuel cell has been adopted in order to reduce the number of components and make the entire fuel cell stack compact. In this thin-out cooling type fuel cell, two electrolyte / electrode structures are sequentially disposed between three separators to constitute a fuel cell unit. And while forming a cooling medium flow path between each fuel cell unit and laminating | stacking the said fuel cell unit, the fuel cell stack is comprised.

  The present invention relates to this type of thinned cooling fuel cell. With a simple configuration, positioning of at least three separators can be performed easily and efficiently, and desired rigidity can be ensured. An object of the present invention is to provide a simple fuel cell stack.

  The present invention includes at least first and second electrolyte / electrode structures provided with a pair of electrodes on both sides of an electrolyte, and at least first, second, and third separators, and the first separator and the second separator. A fuel cell unit configured to sandwich the second electrolyte / electrode structure between the second separator and the third separator, while sandwiching the first electrolyte / electrode structure between the first separator and the third separator, And a positioning mechanism for positioning the first to third separators with each other.

  The positioning mechanism includes a first convex portion projecting from one surface of the second separator to the first separator side, a second convex portion projecting from the other surface of the second separator to the third separator side, A first concave portion provided on the first separator and fitted with the first convex portion, and a second concave portion provided on the third separator and fitted with the second convex portion. Yes.

  In addition, the first to third separators are constituted by first to third metal separators, and first and second convex portions are integrally formed of a resin material in the first metal separator, and the second In the third metal separator, the first and second concave portions are preferably integrally formed of a resin material. For this reason, the positioning mechanism greatly reduces the number of parts, and the positioning operation of the first to third separators can be performed easily and quickly.

  In addition, since the first and second convex portions and the inner wall surfaces of the first and second concave portions are formed of a resin material, the surface slipperiness is good. As a result, the first and second convex portions and the first and second concave portions can be fitted smoothly and reliably, and the insulating property of the fitting portion can be ensured.

  Furthermore, it is preferable that the first convex portion and the second convex portion have different diameters or shapes. Since the first convex portion and the second concave portion and the second convex portion and the first concave portion do not fit with each other, the order of the first to third separators is changed and misassembly occurs. This is because it can be reliably prevented.

  Furthermore, the first and second convex portions are provided on the positioning member, and one positioning member of the adjacent fuel cell unit is formed with a protrusion that fits into an opening provided in the other positioning member. The positioning members are preferably positioned with respect to each other. This is because it becomes possible to easily and accurately position adjacent fuel cell units.

  According to the present invention, the first convex portion projecting toward the first separator side and the second convex portion projecting toward the third separator side are provided on both surfaces of the second separator disposed substantially at the center of the fuel cell unit. The first and third separators on both sides are positioned with reference to the second separator. Therefore, the first to third separators can be accurately positioned with a simple configuration and operation. Further, for example, the first and second convex portions are shortened and the rigidity of the first and second convex portions is effectively improved as compared with the configuration in which the first separator or the third separator is provided with the convex portions. To do.

It is a schematic structure explanatory view of a fuel cell stack concerning an embodiment of the present invention. FIG. 2 is an exploded perspective view of a fuel cell unit constituting the fuel cell stack. It is a front view of the 1st separator which comprises the said fuel cell unit. It is a cross-sectional enlarged explanatory view of a positioning mechanism for positioning the fuel cell unit. It is a principal part disassembled perspective view of the said positioning mechanism. FIG. 4 is an explanatory cross-sectional view when the fuel cell units are stacked.

  FIG. 1 is a schematic configuration explanatory diagram of a fuel cell stack 10 according to an embodiment of the present invention.

  The fuel cell stack 10 includes a stacked body 14 in which a plurality of fuel cell units 12 are stacked in the direction of arrow A. Terminal plates 16a and 16b, insulating plates 18a and 18b, and end plates 20a and 20b are disposed at both ends in the stacking direction of the laminate 14, and a predetermined tightening load is applied between the end plates 20a and 20b. Has been.

  As shown in FIG. 2, the fuel cell unit 12 includes at least first and second electrolyte membrane (electrolyte) / electrode structures 22a and 22b and at least first, second and third separators 24, 26 and 28. Provide. The first electrolyte membrane / electrode structure 22a is sandwiched between the first separator 24 and the second separator 26, while the second electrolyte membrane / electrode structure 22b is sandwiched between the second separator 26 and the third separator 28. To do. Although the first to third separators 24, 26, and 28 are made of metal separators, for example, carbon separators may be adopted.

  An oxidant gas for supplying an oxidant gas, for example, an oxygen-containing gas, communicates with each other in the direction of the arrow A at one end edge in the long side direction (the arrow B direction in FIG. 2) of the fuel cell unit 12. An inlet communication hole 30a and a fuel gas outlet communication hole 32b for discharging a fuel gas, for example, a hydrogen-containing gas, are provided.

  The other end edge of the long side direction of the fuel cell unit 12 communicates with each other in the direction of arrow A, and a fuel gas inlet communication hole 32a for supplying fuel gas, and an oxidant for discharging oxidant gas A gas outlet communication hole 30b is provided.

  A cooling medium inlet communication hole 34a for supplying a cooling medium is provided at the upper end edge of the fuel cell unit 12, and a cooling medium for discharging the cooling medium is provided at the lower end edge of the fuel cell unit 12. An outlet communication hole 34b is provided.

  The first and second electrolyte membrane / electrode structures 22a and 22b include, for example, a solid polymer electrolyte membrane 36 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side sandwiching the solid polymer electrolyte membrane 36 The electrode 38 and the cathode side electrode 40 are provided.

  The anode side electrode 38 and the cathode side electrode 40 are uniformly coated on the surface of the gas diffusion layer with a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface. And an electrode catalyst layer (not shown) formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 36.

  As shown in FIG. 3, the first fuel gas flow that communicates the fuel gas inlet communication hole 32a and the fuel gas outlet communication hole 32b to the surface 24a of the first separator 24 toward the first electrolyte membrane / electrode structure 22a. A path 42 is formed. The first fuel gas channel 42 is constituted by, for example, a plurality of grooves extending in the arrow B direction. As shown in FIG. 2, a cooling medium flow path 44 that connects the cooling medium inlet communication hole 34 a and the cooling medium outlet communication hole 34 b is formed on the surface 24 b of the first separator 24. The cooling medium flow path 44 is configured by a plurality of grooves extending in the arrow C direction.

  The surface 26a of the second separator 26 facing the first electrolyte membrane / electrode structure 22a is provided with, for example, a first oxidant gas channel 46 composed of a plurality of grooves extending in the direction of arrow B. The one oxidant gas passage 46 communicates with the oxidant gas inlet communication hole 30a and the oxidant gas outlet communication hole 30b. A second fuel gas channel 48 that connects the fuel gas inlet communication hole 32a and the fuel gas outlet communication hole 32b is formed on the surface 26b of the second separator 26 that faces the second electrolyte membrane / electrode structure 22b.

  A second oxidant gas flow path 50 communicating with the oxidant gas inlet communication hole 30a and the oxidant gas outlet communication hole 30b is provided on a surface 28a of the third separator 28 facing the second electrolyte membrane / electrode structure 22b. . A cooling medium flow path 44 is integrally formed on the surface 28 b of the third separator 28 so as to overlap the surface 24 b of the first separator 24.

  A first seal member 52 is integrally formed on the surfaces 24 a and 24 b of the first separator 24 around the outer peripheral edge of the first separator 24. On the surfaces 26a and 26b of the second separator 26, the second seal member 54 is integrally formed around the outer peripheral edge of the second separator 26, and on the surfaces 28a and 28b of the third separator 28, A third seal member 56 is integrally formed around the outer peripheral edge of the third separator 28.

  The fuel cell stack 10 includes a positioning mechanism 60 for positioning the first to third separators 24, 26 and 28 constituting the fuel cell unit 12 with each other. The positioning mechanism 60 includes a resin material-made positioning member 62 that is integrally formed with both edge portions in the arrow B direction of the second separator 26. As the resin material, for example, PPS (polyphenylene sulfide), LCP (liquid crystal polymer), or the like that is excellent in insulation, injection moldability, and hardness is used. The same applies hereinafter.

  The positioning member 62 is integrally formed on the metal plate when the second seal member 54 is integrally formed on the metal plate after the metal plate constituting the second separator 26 is formed and trimmed. After the second seal member 54 is integrally formed, it is attached to the metal plate.

  As shown in FIGS. 4 and 5, the positioning member 62 has a substantially ring shape, a first convex portion 64 projecting from the surface 26 a to the first separator 24 side, and a surface 26 b from the third separator 28 side. It has the 2nd convex-shaped part 66 which protrudes. The first convex portion 64 is formed by cutting out the ring-shaped portion by a predetermined angle, for example, projecting at three locations, and the second convex portion 66 is similarly formed by cutting out the ring-shaped portion by a predetermined angle. For example, it is protrudingly formed at three locations. The outer peripheral diameter of the first convex portion 64 is set to be larger than the outer peripheral diameter of the second convex portion 66.

  The positioning member 62 is provided with a circular hole (opening) 68 on the first convex portion 64 side, while being fitted in the hole 68 of another positioning member 62 on the second convex portion 66 side. A protrusion 70 for positioning the positioning members 62 is formed to bulge in the axial direction (arrow A direction).

  A first ring member 72 made of a resin material is integrally formed at both end edges in the arrow B direction of the first separator 24 (see FIGS. 2 and 3). The first ring member 72 is formed with a first hole portion (first concave portion) 74 into which the first convex portion 64 of the second separator 26 is fitted (see FIGS. 4 and 5).

  A second ring member 76 made of a resin material is integrally formed at both edges of the third separator 28 in the direction of arrow B (see FIG. 2), and the second ring member 76 includes a second ring member 76. A second hole (second concave portion) 78 into which the two convex portions 66 are fitted is formed (see FIGS. 4 and 5). The opening diameter of the first hole 74 is set larger than the opening diameter of the second hole 78.

  As shown in FIG. 2, a guide portion 80 that is integrally formed of the same material as the positioning member 62 is provided on the outer peripheral surface of the second separator 26, for example, at one edge of the arrow B direction so as to protrude outward. .

  Next, the operation of assembling the fuel cell stack 10 will be described below.

  First, in the fuel cell unit 12, the first electrolyte membrane / electrode structure 22 a is disposed between the first separator 24 and the second separator 26, and between the second separator 26 and the third separator 28. The second electrolyte membrane / electrode structure 22b is disposed (see FIG. 2). In this state, the first to third separators 24, 26, and 28 are pressed in the stacking direction (arrow A direction).

  For this reason, as shown in FIGS. 4 and 5, in the positioning member 62 integrally formed with the second separator 26, the first ring member 72 in which the first convex portion 64 is integrally formed with the first separator 24. The first hole 74 is fitted. On the other hand, the second convex portion 66 of the positioning member 62 is fitted into the second hole 78 of the second ring member 76 that is integrally formed with the third separator 28. Accordingly, the first to third separators 24, 26 and 28 are positioned via the positioning mechanism 60 and the fuel cell unit 12 is assembled.

  Thus, in the present embodiment, the first convex portion 64 and the second convex portion 66 are provided on both surfaces 26a, 26b of the second separator 26 disposed in the center of the fuel cell unit 12, and this The first and third separators 24 and 28 on both sides are positioned with respect to the second separator 26. Specifically, the first convex portion 64 of the second separator 26 is fitted into the first hole 74 of the first separator 24, while the second convex portion 66 of the second separator 26 is third. The separator 28 is fitted in the second hole 78.

  For this reason, in the positioning mechanism 60, the effect that the 1st thru | or 3rd separators 24, 26, and 28 can be accurately positioned with a simple structure and operation | work is acquired.

  Further, for example, the first and second convex portions are provided in the first separator 24, and the first and second convex portions are compared with the configuration in which the convex portions are integrally penetrated through the second and third separators 26 and 28 for positioning. The axial lengths of the portions 64 and 66 are greatly shortened. Accordingly, there is an advantage that the rigidity of the first and second convex portions 64 and 66 is effectively improved, draft angle and bending are not easily generated, and the positioning accuracy is maintained well.

  In the present embodiment, the first to third separators 24, 26, and 28 are formed of metal separators, and the first ring member 72, the positioning member 62, and the second ring member 76 are integrally formed of a resin material. Has been. Therefore, in the positioning mechanism 60, the number of parts is greatly reduced, and the positioning work of the first to third separators 24, 26, and 28 is easily and quickly performed.

  In addition, since the first and second convex portions 64 and 66 and the inner wall surfaces of the first and second hole portions 74 and 78 are formed of a resin material, it is possible to ensure the insulation of the fitting portion. It becomes possible.

  Further, the first convex portion 64 is formed to have a larger diameter than the second convex portion 66, and the first hole 74 is set to have an opening diameter larger than that of the second hole portion 78. . As a result, the first convex portion 64 of the second separator 26 does not fit into the second hole 78 of the third separator 28, and the order of the first to third separators 24, 26 and 28 is changed. There is an effect that it is possible to reliably prevent the occurrence of misassembly.

  The fuel cell units 12 assembled as described above are stacked together along the guide rail 90 as shown in FIG. At that time, in each fuel cell unit 12, a guide portion 80 is bulged and formed on the side portion of the second separator 26 disposed substantially at the center. Therefore, the fuel cell units 12 can be easily and accurately stacked by simply guiding the guide portion 80 along the guide rail 90.

  Further, when the fuel cell units 12 are stacked, the protrusions 70 provided on one positioning member 62 are fitted in the holes 68 provided on the other positioning member 62. For this reason, there exists an advantage that positioning of the fuel cell units 12 is performed easily and accurately.

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

  First, as shown in FIG. 1, in the fuel cell stack 10, an oxidant gas (air) such as an oxygen-containing gas is supplied and a fuel gas such as a hydrogen-containing gas is supplied. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied.

  As shown in FIG. 2, the oxidant gas is supplied to the oxidant gas inlet communication hole 30a of the fuel cell unit 12 and moves in the direction of the arrow A. 3 is introduced into the second oxidant gas flow path 50 of the separator 28. The oxidant gas introduced into the first oxidant gas flow path 46 moves along the cathode side electrode 40 of the first electrolyte membrane / electrode structure 22a, while being introduced into the second oxidant gas flow path 50. The oxidant gas moves along the cathode side electrode 40 of the second electrolyte membrane / electrode structure 22b.

  The fuel gas is introduced into the first fuel gas channel 42 of the first separator 24 and the second fuel gas channel 48 of the second separator 26 from the fuel gas inlet communication hole 32 a of the fuel cell unit 12. Therefore, the fuel gas moves along the anode-side electrodes 38 of the first and second electrolyte membrane / electrode structures 22a and 22b.

  Therefore, in the first and second electrolyte membrane / electrode structures 22a and 22b, the oxidant gas supplied to each cathode side electrode 40 and the fuel gas supplied to each anode side electrode 38 are in the electrode catalyst layer. In this way, it is consumed by an electrochemical reaction to generate electricity.

  Next, the oxidant gas supplied to and consumed by each cathode side electrode 40 flows along the oxidant gas outlet communication hole 30 b and is then discharged from the fuel cell stack 10. Similarly, the fuel gas supplied to and consumed by each anode side electrode 38 is discharged to the fuel gas outlet communication hole 32 b, flows, and is discharged from the fuel cell stack 10.

  The cooling medium flows along the direction of arrow C after being introduced into the cooling medium flow path 44 between the fuel cell units 12 from the cooling medium inlet communication hole 34a. After the first and second electrolyte membrane / electrode structures 22a and 22b are thinned and cooled, the cooling medium moves through the cooling medium outlet communication hole 34b and is discharged from the fuel cell stack 10.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 12 ... Fuel cell unit 22a, 22b ... Electrolyte membrane and electrode structure 24, 26, 28 ... Separator 36 ... Solid polymer electrolyte membrane 38 ... Anode side electrode 40 ... Cathode side electrode 42, 48 ... Fuel gas Flow path 44 ... Cooling medium flow path 46, 50 ... Oxidant gas flow path 60 ... Positioning mechanism 62 ... Positioning member 64, 66 ... Convex part 68 ... Hole part 70 ... Projection part 72, 76 ... Ring member 74, 78 ... Hole 80 ... Guide part

Claims (4)

At least first and second electrolyte / electrode structures provided with a pair of electrodes on both sides of the electrolyte, and at least first, second and third separators are provided between the first separator and the second separator. while sandwiching the first electrolyte electrode assembly, a second separator and the fuel cell stack Ru comprising a fuel cell unit for clamping the second electrolyte electrode assembly between said third separator,
Wherein the first to third separators, together with the resin positioning member for positioning one another is provided by the convex portion is fitted into the concave portion,
Wherein the outer periphery of the second separator, a fuel cell stack plastic guide portion for positioning the fuel cell unit to each other and said Rukoto protrudes outwardly disposed in the center. 2. The fuel cell stack according to claim 1, wherein the resin guide portion is integrally formed with the resin positioning member provided in the second separator . The fuel cell stack according to claim 1 or 2, wherein the resin positioning member includes a first convex portion projecting from one surface of the second separator toward the first separator ,
A second convex portion projecting from the other surface of the second separator to the third separator side ;
A first concave portion provided in the first separator and into which the first convex portion is fitted;
A second concave portion provided in the third separator and into which the second convex portion is fitted;
The fuel cell stack according to claim Rukoto to have a. The fuel cell stack according to any one of claims 1 to 3, wherein the first to third separators are configured of first to third metal separators .

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