JP4118123B2 - Fuel cell stack - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention has an electrolyte / electrode structure in which a pair of electrodes are provided on both sides of an electrolyte, and includes a laminate in which a plurality of the electrolyte / electrode structures and separators are laminated, and terminal plates at both ends of the laminate. The present invention relates to a fuel cell stack in which an insulating plate and an end plate are stacked.
[0002]
[Prior art]
For example, a polymer electrolyte fuel cell has an electrolyte membrane (electrolyte) / electrode structure in which an anode side electrode and a cathode side electrode are respectively provided on both sides of an electrolyte membrane made of a polymer ion exchange membrane (cation exchange membrane). Is sandwiched between separators.
[0003]
In this fuel cell, a fuel gas supplied to the anode side electrode, for example, a gas mainly containing hydrogen (hereinafter, also referred to as a hydrogen-containing gas) is ionized on the electrode catalyst, and the cathode side passes through the electrolyte. Move to the electrode side. Electrons generated in the meantime 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 react to produce water.
[0004]
By the way, this type of fuel cell normally comprises a laminated body in which a predetermined number of electrolyte / electrode structures and separators are laminated, and a terminal plate for collecting electric power generated by each fuel cell at both ends of the laminated body The fuel cell stack is provided with an end plate for holding the laminate and the terminal plate, and an insulating plate for insulating the terminal plate and the end plate.
[0005]
For example, when this fuel cell stack is used for in-vehicle use, it is necessary to stack and stack a considerably large number (for example, several hundreds) of fuel cells in order to obtain a desired high output. For this reason, a relatively large load (inertial force) tends to act on the fuel cell stack when the vehicle suddenly starts or stops.
[0006]
In particular, when a load is applied to the fuel cell stack when the stacking direction of the fuel cell stack is set to be substantially the same as the traveling direction of the vehicle, each plate disposed at one end of the stacking direction of the fuel cell stack There is a possibility that a gap may be generated between the terminal plate and the insulating plate and between the insulating plate and the end plate. Thereby, there exists a problem that the sealing performance of the fuel gas and cooling medium supplied in a fuel cell stack falls.
[0007]
Therefore, for example, a fuel cell disclosed in Patent Document 1 is employed. As shown in FIG. 6, this fuel cell includes a cell stack 3 in which unit cells 1 and a frame 2 are stacked. A terminal portion 5 is disposed between the end face M in the stacking direction and the base plate 4. The terminal portion 5 includes a current collecting portion 6 having conductivity, one end portion connected to the current collecting portion 6, and the other end portion passing through the through hole 4 a of the base plate 4. And a conductive rod 7 projecting outward. A threaded portion 8 is formed on the outer periphery of the rod-shaped body 7, and a nut member 9 is screwed into the threaded portion 8.
[0008]
In such a configuration, the current collector 6 is fixed to the base plate 4 by screwing the nut member 9 into the screw portion 8. For this reason, the current collector 6 can be reliably held on the base plate 4, and the contact state between the current collector 6 and the end face M of the cell stack 3 can be improved.
[0009]
[Patent Document 1]
Japanese Patent Laid-Open No. 6-290803 (paragraphs [0008] and [0029], FIG. 2)
[0010]
[Problems to be solved by the invention]
However, in Patent Document 1 described above, since the rod-shaped body 7 is in contact with the base plate 4, there is a possibility that the base plate 4 is energized. Therefore, the base plate 4 must be formed of an insulating material, and the desired rigidity cannot be maintained when the base plate 4 is used as an end plate. Thereby, a predetermined tightening load cannot be applied to the cell stack 3 in the stacking direction, and there is a problem that power generation performance is deteriorated.
[0011]
The present invention solves this type of problem, and an object thereof is to provide a fuel cell stack capable of effectively ensuring the sealing performance between the plates and maintaining desired power generation performance.
[0012]
[Means for Solving the Problems]
The fuel cell stack according to claim 1 of the present invention includes a fixing mechanism for fixing the terminal plate, the insulating plate, and the end plate. The fixing mechanism is provided on the terminal plate, and has a screw member that penetrates the insulating plate and the end plate, and is disposed on the end plate side, and is screwed into the screw member to be connected to the terminal plate, the insulating plate, and the end plate. And an insulative nut member that integrally fixes the nut.
[0013]
As described above, when the screw member provided on the terminal plate is disposed through the insulating plate and the end plate, the insulating nut member is screwed into the screw member, whereby the terminal plate, the insulating plate, The plate and the end plate are fixed together. Therefore, when an inertial force is applied to the fuel cell stack in the stacking direction, the terminal plate, the insulating plate, and the end plate, which are the plates, are firmly held to each other and the plates are not separated more than necessary. It is possible to effectively ensure the sealing performance.
[0014]
In addition, the terminal plate and the end plate are formed by using the insulating nut member and the insulating plate having a cylindrical portion that is inserted into the end plate and disposed between the end plate and the insulating nut member. Can be reliably insulated. As a result, the terminal plate, the insulating plate, and the end plate can ensure the desired sealing performance without impairing their functions.
[0015]
Also, roots Ji member comprises a rod-shaped power take-out terminals provided on the terminal plate, the screws are formed on the outer periphery of the rod-shaped power take-out terminal. For this reason, the rod-shaped power extraction terminal of the terminal plate can also serve as the screw member constituting the fixing mechanism, and the number of parts is effectively reduced, which is economical.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic overall configuration explanatory view of a fuel cell stack 10 according to a first embodiment of the present invention, and FIG. 2 is an exploded perspective explanatory view of a main part of the fuel cell stack 10.
[0017]
As shown in FIG. 1, the fuel cell stack 10 includes a stacked body 18 in which a plurality of electrolyte membrane (electrolyte) / electrode structures 12 are stacked with first and second separators 14 and 16 interposed therebetween. The first and second terminal plates 20a and 20b, the first and second end plates 22a and 22b, and the first and second insulating plates 24a and 24b are provided at both ends of the stack 18 in the stacking direction (arrow A direction). It is arranged to be interposed.
[0018]
The electrolyte membrane / electrode structure 12 and the first and second separators 14 and 16 constitute a fuel cell 26. As shown in FIG. 2, a gasket is provided between the electrolyte membrane / electrode structure 12 and the first and second separators 14 and 16 so as to cover the periphery of the communication holes and the outer periphery of the electrode surface (power generation surface) described later. A sealing member 28 such as is interposed.
[0019]
One end edge of the fuel cell 26 in the horizontal direction (arrow B direction in FIG. 2) communicates with each other in the direction of arrow A, which is the stacking direction, to oxidize gas to supply an oxidant gas, for example, an oxygen-containing gas An agent gas supply communication hole 30a, a cooling medium discharge communication hole 32b for discharging a cooling medium, and a fuel gas discharge communication hole 34b for discharging a fuel gas, for example, a hydrogen-containing gas, are provided in the arrow C direction (vertical direction). Are provided in an array.
[0020]
The other end edge of the fuel cell 26 in the direction of arrow B communicates with each other in the direction of arrow A, a fuel gas supply communication hole 34a for supplying fuel gas, and a cooling medium supply communication hole for supplying a cooling medium. 32a and an oxidant gas discharge communication hole 30b for discharging the oxidant gas are arranged in the direction of arrow C.
[0021]
The electrolyte membrane / electrode structure 12 includes, for example, a solid polymer electrolyte membrane 36 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 38 and a cathode side electrode that sandwich the solid polymer electrolyte membrane 36. 40.
[0022]
The anode side electrode 38 and the cathode side electrode 40 are composed of a gas diffusion layer made of a porous carbon member, for example, carbon paper, and porous carbon particles carrying a platinum alloy supported on the surface of the gas diffusion layer. And an electrode catalyst layer applied to each. The electrode catalyst layers are bonded to both surfaces of the solid polymer electrolyte membrane 36 so as to face each other with the solid polymer electrolyte membrane 36 interposed therebetween.
[0023]
An opening 45 is formed at the center of the seal member 28 corresponding to the anode side electrode 38 and the cathode side electrode 40. Instead of the seal member 28, a seal may be provided on the first and second separators 14 and 16 by baking or the like.
[0024]
On the surface 14a of the first separator 14 on the electrolyte membrane / electrode structure 12 side, for example, an oxidant gas flow path 46 including a plurality of grooves extending in the direction of arrow B is provided. The passage 46 communicates with the oxidant gas supply communication hole 30a and the oxidant gas discharge communication hole 30b.
[0025]
A fuel gas passage 48 communicating with the fuel gas supply communication hole 34a and the fuel gas discharge communication hole 34b is formed on the surface 16a of the second separator 16 on the electrolyte membrane / electrode structure 12 side. The fuel gas channel 48 includes a plurality of grooves extending in the arrow B direction. A cooling medium flow path 50 that communicates with the cooling medium supply communication hole 32 a and the cooling medium discharge communication hole 32 b is formed on the surface 16 b of the second separator 16. The cooling medium flow path 50 includes a plurality of grooves extending in the direction of arrow B.
[0026]
As shown in FIG. 1, the fuel cell stack 10 includes a first terminal plate 20a, a first insulating plate 24a, a fixing mechanism 52 for fixing the first end plate 22a, a second terminal plate 20b, a second insulating plate 24b, And a fixing mechanism 53 for fixing the second end plate 22b.
[0027]
As shown in FIGS. 3 and 4, the fixing mechanism 52 includes a rod-shaped power extraction terminal 54 that is fixed to a substantially central portion of the first terminal plate 20 a by brazing or the like. The power take-out terminal 54 has a hole portion 56 formed in a central portion thereof and a screw portion 58 formed on the outer peripheral portion to constitute a screw member.
[0028]
A cylindrical portion 60 is formed at a substantially central portion of the first insulating plate 24a so as to bulge toward the first end plate 22a. The cylindrical portion 60 is set to a shape in which the power extraction terminal 54 can be inserted.
[0029]
A stepped hole 62 is formed in the substantially central portion of the first end plate 22a corresponding to the cylindrical portion 60, and a resin collar (insulating nut member) 64 is disposed on one end side of the stepped hole 62. Is done. The resin collar 64 has a screw hole 66 that is screwed into the screw portion 58 of the power extraction terminal 54 at the center, and a large-diameter flange portion 68 at one end of the outer peripheral portion. The resin collar 64 is inserted into the cylindrical portion 60 of the insulating plate 24, and the flange portion 68 is disposed at one large diameter portion of the stepped hole portion 62 of the first end plate 22a.
[0030]
A set screw 70 is disposed inward of the first terminal plate 20a. The set screw 70 protrudes outward from the tip of the power extraction terminal 54 through the first terminal plate 20a and the hole 56 of the power extraction terminal 54, and the large-diameter flange portion 72 has the power extraction terminal The terminal 54 is locked to the end surface.
[0031]
A lug terminal 74 is disposed at the tip of the set screw 70, and the lug terminal 74 is attached to the power extraction terminal 54 by screwing a nut 76 into the set screw 70. One end of an electric wire 78 is connected to the lug terminal 74, and the electric wire 78 is connected to an external load (not shown).
[0032]
The fixing mechanism 53 is configured in the same manner as the above-described fixing mechanism 52, and the same components are denoted by the same reference numerals, and detailed description thereof is omitted.
[0033]
The operation of the fuel cell stack 10 configured as described above will be described below.
[0034]
First, as shown in FIG. 2, a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas supply passage 34a, and an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas supply passage 30a. Further, a coolant such as pure water, ethylene glycol, or oil is supplied to the coolant supply passage 32a.
[0035]
For this reason, the oxidant gas is introduced into the oxidant gas flow path 46 of the first separator 14 from the oxidant gas supply communication hole 30 a and moves along the cathode side electrode 40 constituting the electrolyte membrane / electrode structure 12. . On the other hand, the fuel gas is introduced into the fuel gas passage 48 of the second separator 16 from the fuel gas supply communication hole 34 a and moves along the anode side electrode 38 constituting the electrolyte membrane / electrode structure 12.
[0036]
Therefore, in each electrolyte membrane / electrode structure 12, the oxidant gas supplied to the cathode side electrode 40 and the fuel gas supplied to the anode side electrode 38 are consumed by an electrochemical reaction in the electrode catalyst layer, Power generation is performed.
[0037]
Next, the fuel gas consumed by being supplied to the anode side electrode 38 is discharged in the direction of arrow A along the fuel gas discharge communication hole 34b. Similarly, the oxidant gas consumed by being supplied to the cathode side electrode 40 is discharged in the direction of arrow A along the oxidant gas discharge communication hole 30b.
[0038]
In addition, the cooling medium supplied to the cooling medium supply communication hole 32a is introduced into the cooling medium flow path 50 of the second separator 16, and then circulates in the direction of the arrow B. This cooling medium is discharged from the cooling medium discharge communication hole 32b after the electrolyte membrane / electrode structure 12 is cooled.
[0039]
In this case, in the first embodiment, as shown in FIG. 4, the first terminal plate 20a, the first insulating plate 24a, and the first end plate 22a are stacked and fixed to the first terminal plate 20a. The power extraction terminal 54 is inserted into the cylindrical portion 60 of the first insulating plate 24a and the stepped hole portion 62 of the first end plate 22a. Then, the resin collar 64 is screwed into the screw portion 58 of the power extraction terminal 54.
[0040]
Accordingly, the first terminal plate 20a, the first insulating plate 24a, and the first end plate 22a are integrally and firmly fixed via the fixing mechanism 52. For this reason, for example, when an inertial force in the stacking direction (arrow A direction) is applied to the on-vehicle fuel cell stack 10 at the time of a sudden stop or sudden start, the first terminal plate 20a, the first insulating plate 24a, and The first end plates 22a are firmly held to each other so that the distance between them is not much larger than necessary.
[0041]
Thereby, in 1st Embodiment, the effect that it becomes possible to ensure effectively the sealing performance between the 1st terminal plate 20a, the 1st insulating plate 24a, and the 1st end plate 22a is acquired.
[0042]
Furthermore, a power takeout terminal 54 fixed to the first terminal plate 20 a as a screw member is provided, and a screw portion 58 is formed on the outer periphery of the power takeout terminal 54. For this reason, the power takeout terminal 54 can also be used as a screw member constituting the fixing mechanism 52, and there is an advantage that the number of parts is effectively reduced and it is economical.
[0043]
Furthermore, a resin collar 64 is used as the nut member, and the power extraction terminal 54 and the first end plate 22a are insulated via the resin collar 64. Accordingly, the first terminal plate 20a, the first insulating plate 24a, and the first end plate 22a do not impair their functions and can secure a desired sealing property.
[0044]
In the fixing mechanism 53, the second terminal plate 20b, the second insulating plate 24b, and the second end plate 22b are firmly and securely held in the same manner as the fixing mechanism 52 described above. Thereby, the fixing mechanism 53 can obtain the same effect as the above-described fixing mechanism 52, such as being able to ensure a desired sealing property even when an inertial force is applied.
[0045]
FIG. 5 is a partial perspective explanatory view 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.
[0046]
In the fuel cell stack 80, a first terminal plate 82, a first insulating plate 84, and a first end plate 86 are stacked on one end of the stacked body 18. The first terminal plate 82 is formed with a plate-shaped power extraction terminal 88, and the power extraction terminal 88 protrudes above the fuel cell stack 80 and is connected to an external load (not shown).
[0047]
The fixing mechanism 90 constituting the fuel cell stack 80 includes screw members 92a and 92b that form, for example, a fuel gas supply communication hole 34a and a fuel gas discharge communication hole 34b among the communication holes. Screws 94a and 94b are formed on the outer periphery of the screw members 92a and 92b.
[0048]
In the first insulating plate 84, cylindrical portions 96a and 96b are bulged or separately formed on the first end plate 86 side corresponding to the fuel gas supply communication hole 34a and the fuel gas discharge communication hole 34b. In the first end plate 86, stepped holes 98a and 98b for inserting the cylindrical portions 96a and 96b are formed. On the outside of the first end plate 86, resin collars (insulating nut members) 100a and 100b are disposed.
[0049]
In addition, although not shown in figure, the 2nd terminal plate, the 2nd insulating plate, and the 2nd end plate are similarly hold | maintained integrally through the fixing mechanism in the other edge part of the laminated body 18.
[0050]
In the second embodiment configured as described above, the screw members 92 a and 92 b of the first terminal plate 82 pass through the cylindrical portions 96 a and 96 b of the first insulating plate 84 and the stepped holes of the first end plate 86. It is inserted into the portions 98a and 98b. The screw holes 66 of the resin collars 100a and 100b are screwed into the screws 94a and 94b of the screw members 92a and 92b protruding outward from the first end plate 86. Accordingly, the first terminal plate 82, the first insulating plate 84, and the first end plate 86 are integrally and firmly held via the fixing mechanism 90.
[0051]
Therefore, even if an inertial force acts on the fuel cell stack 80 in the stacking direction, the first terminal plate 82, the first insulating plate 84, and the first end plate 86 are separated more than necessary under the action of the fixing mechanism 90. There is no. For this reason, the effect similar to 1st Embodiment is acquired, such as being able to ensure desired sealing performance favorably.
[0052]
Furthermore, in the second embodiment, the diagonal positions of the first terminal plate 82, the first insulating plate 84, and the first end plate 86, that is, the fuel gas supply communication hole 34a and the fuel gas discharge communication hole 34b. Corresponding to these, screw members 92a and 92b are provided. Then, the resin collars 100a and 100b are screwed into the screw members 92a and 92b, whereby the first terminal plate 82, the first insulating plate 84, and the first end plates 86 can be held more firmly and reliably. There are advantages.
[0053]
The fixing mechanism 90 may be provided in the oxidant gas supply communication hole 30a and the oxidant gas discharge communication hole 30b instead of the fuel gas supply communication hole 34a and the fuel gas discharge communication hole 34b, or these four locations. May be provided.
[0054]
【The invention's effect】
In the fuel cell stack according to the present invention, the screw member provided on the terminal plate is disposed through the insulating plate and the end plate, and the insulating nut member is screwed to the screw member. The terminal plate, the insulating plate and the end plate are fixed together. Therefore, when an inertial force is applied to the fuel cell stack in the stacking direction, the terminal plate, the insulating plate, and the end plate, which are the plates, are firmly held to each other and the plates are not separated more than necessary. It is possible to effectively ensure the sealing performance.
[0055]
In addition, the terminal plate and the end plate can be reliably insulated by using the insulating nut member. As a result, the terminal plate, the insulating plate, and the end plate can ensure the desired sealing performance without impairing their functions.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a schematic overall configuration of a fuel cell stack according to a first embodiment of the present invention.
FIG. 2 is an exploded perspective view of a main part of the fuel cell stack.
FIG. 3 is an exploded perspective view of a fixing mechanism constituting the fuel cell stack.
FIG. 4 is an explanatory sectional view of the fixing mechanism.
FIG. 5 is a partially exploded perspective view of a fuel cell stack according to a second embodiment of the present invention.
FIG. 6 is an exploded perspective view of a main part of a conventional fuel cell.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10, 80 ... Fuel cell stack 12 ... Electrolyte membrane electrode assembly 14, 16 ... Separator 18 ... Laminated body 20a, 20b, 82, 92 ... Terminal plate 22a, 22b, 86 ... End plate 24, 24a, 24b, 84 ... Insulating plate 26 ... Fuel cell 36 ... Solid polymer electrolyte membrane 38 ... Anode side electrode 40 ... Cathode side electrode 52, 53, 90 ... Fixing mechanism 54, 88 ... Power extraction terminal 58 ... Screw part 60, 96a, 96b ... Cylindrical part 62, 98a, 98b ... Stepped holes 64, 100a, 100b ... Resin collar 66 ... Screw holes 68, 72 ... Flange 70 ... Set screw 74 ... Lug terminal 78 ... Electric wires 92a, 92b ... Screw members 94a, 94b ... screw

Claims (2)

An electrolyte / electrode structure having a pair of electrodes provided on both sides of the electrolyte, and a laminate in which a plurality of the electrolyte / electrode structures and separators are laminated, and a terminal plate, an insulating plate, and A fuel cell stack in which end plates are stacked,
A fixing mechanism for fixing the terminal plate, the insulating plate and the end plate;
The fixing mechanism is provided on the terminal plate, and a screw member that penetrates the insulating plate and the end plate;
An insulating nut member disposed on the end plate side and screwed into the screw member to integrally fix the terminal plate, the insulating plate and the end plate;
Equipped with a,
The screw member has a rod-shaped power extraction terminal provided on the terminal plate, and a screw is formed on the outer periphery of the rod-shaped power extraction terminal.
The insulating plate, the fuel cell stack, characterized in Rukoto to have a cylindrical portion which is disposed between the end plate and the insulating nut member is inserted into the end plate. The fuel cell stack according to claim 1, wherein, before Kibo shaped power take-out in the terminal, along with a set screw is arranged,
The tip of the set screw, the fuel cell stack, characterized in Rukoto protruding outwardly from the tip portion of the rod-shaped power take-out terminal.

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