JP2001185174A - Gasket for fuel cell and method of molding the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems in a gasket used for a fuel cell to be thinned at its seal, improved in assembly, prevented from being dislocated, lower and equal in surface pressure. SOLUTION: A gasket lip 73 formed of a liquid rubber cured material is integrally molded on the surface or in a groove formed in the surface of a flat plate 71 formed of a porous carbon, graphite, conductive phenol resin or magnesium alloy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gasket for a fuel cell and a method of forming the same.

[0002]

2. Description of the Related Art As shown in FIG. 21, for example, a collector electrode (separator) 2 of a fuel cell, an ion exchange membrane 3 sandwiched therebetween, and a membrane-fixed reaction electrode 4 fixed to the ion exchange membrane 3 are provided. Each of them is formed of a flat plate-shaped porous carbon material, and these components are combined to form the fuel cell 1. As a material of the flat plate, graphite or the like is used in addition to carbon, and conductive phenol or a magnesium alloy may be used.

[0003] As for such a fuel cell 1 and a seal between its constituent elements, a single gasket is conventionally used (Japanese Patent Application Laid-Open Nos. 9-231987, 7-226220 or 7-226220). -1534
Japanese Patent Application Laid-Open No. 7-310223), and a device in which a foamed sponge layer 6 is superimposed on a rubber plate 5 and used as a gasket as shown in FIG. None of them are intended to solve the problems of thinning the seal part, improving the assemblability, preventing displacement, reducing the surface pressure, and making the surface pressure uniform, that is, these conventional separate gaskets are not used. Means thinner seals,
There are inconveniences that these cannot be sufficiently satisfied in terms of improving assemblability, preventing displacement, reducing surface pressure, and uniformizing surface pressure. Insufficiency, functional instability, etc. may occur.

When a gasket is molded by a known molding method, a weld defect is apt to occur at the end of the material flow path, and it is difficult to mold the lip of that portion in the shape of a mold. This is the largest factor that impairs the sealing performance.

Therefore, in order to prevent such a problem from occurring, vacuum forming is generally performed, and the conventional vacuum forming method includes a method of providing a vacuum path in the middle of a material flow path and performing vacuuming. And a method in which the entire mold is surrounded by a vacuum chamber to perform evacuation.

However, in the former method, since a low-viscosity material which is a molding material of the gasket may flow into the evacuation path, there is a disadvantage that stable molding of the gasket is hindered. Further, the latter method has a disadvantage that the structure of the mold portion is complicated and has to be expensive, and furthermore, there is a disadvantage that the evacuation volume becomes excessively large and the cycle time is adversely affected.

[0007]

SUMMARY OF THE INVENTION In view of the above, the present invention provides a gasket used for a fuel cell as described above, in which the thickness of the seal portion is reduced, the assemblability is improved, the displacement is prevented, and the surface pressure is reduced. The object of the present invention is to provide a gasket capable of solving the problem of uniform surface pressure and a method for molding the gasket. In addition, the gasket can be molded stably, and the configuration of the mold apparatus is relatively simple. Another object of the present invention is to provide a method of forming a gasket having a relatively short cycle time.

[0008]

To achieve the above object, a gasket for a fuel cell according to claim 1 of the present invention comprises:
A gasket lip made of a cured liquid rubber is integrally formed on the surface of a flat plate made of porous carbon, graphite, conductive phenol resin, magnesium alloy, or the like, or on a groove provided on the surface. .

According to a second aspect of the present invention, there is provided the gasket for a fuel cell according to the first aspect, wherein the flat plate is a collecting electrode, an ion exchange membrane, or a membrane-fixed reaction electrode. There is a feature.

[0010] Further, according to the gasket for a fuel cell according to claim 3 of the present invention, in the gasket for a fuel cell according to the above-mentioned claim 1, the cured liquid rubber has a hardness (JIS).
A) It is characterized by being 60 or less.

A gasket for a fuel cell according to a fourth aspect of the present invention has a gasket lip made of a cured liquid rubber integrally formed on a surface of an electrode or a groove formed on the surface, and has an electrolyte membrane portion. The pair of gasket lips arranged so as to be sandwiched are formed so that the cross-sectional shapes thereof are different from each other, and one of the gasket lips has a flat portion having a predetermined width in contact with the electrolyte membrane portion. It is characterized by the following.

A gasket for a fuel cell according to a fifth aspect of the present invention has a gasket lip made of a cured liquid rubber integrally formed on a surface of an electrode or a groove provided on the surface, and has an electrolyte membrane portion. At least one of the pair of gasket lips disposed so as to be sandwiched between the gasket lip and the gasket lip is formed with a flat portion having a predetermined width and in contact with the electrolyte membrane portion.

[0013] A gasket for a fuel cell according to a sixth aspect of the present invention has a gasket lip made of a cured liquid rubber integrally formed on a surface of an electrode or a groove formed on the surface, and has an ion exchange membrane. At least one of the pair of gasket lips arranged so as to be sandwiched between the gasket lip and the gasket lip is formed with a flat portion having a predetermined width and in contact with the ion exchange membrane.

According to a seventh aspect of the present invention, there is provided a gasket for a fuel cell according to the first aspect of the present invention, wherein a projection along a gasket lip line is provided on a flat plate so as to cover the projection. A gasket lip is formed.

According to the gasket for a fuel cell according to the eighth aspect of the present invention, in the gasket for a fuel cell according to the first aspect, a projection is provided on the flat plate along the gasket lip line, and the projection is adhered to the center. And a gasket lip formed so as to cover the area.

According to a ninth aspect of the present invention, there is provided a method of forming a gasket for a fuel cell according to any one of the first to eighth aspects, wherein a gap is provided between the upper and lower dies before injection. Is provided, and the gasket lip is injection molded.

According to a tenth aspect of the present invention, there is provided a method of forming a gasket for a fuel cell according to the ninth aspect, wherein the groove is formed on both surfaces of the flat plate or both surfaces. And a gasket lip is integrally formed on both surfaces or both groove portions simultaneously through the through holes.

The gasket for a fuel cell according to the first aspect of the present invention having the above-described structure is provided with a collecting electrode, an ion-exchange membrane, a membrane-fixed reaction membrane, and the like in order to solve the above-mentioned disadvantages in the prior art. A gasket lip made of a liquid rubber cured material, which is a low-viscosity material, is integrally molded on the surface of a flat plate made of this, thereby reducing the thickness of the seal portion, improving the assemblability, preventing displacement, reducing the surface pressure and This is to make the surface pressure uniform. When a gasket lip made of a liquid rubber cured material, which is a low-viscosity material, is integrally formed in the groove provided on the surface of the flat plate, the gasket lip is integrated not only on the bottom but also on the side of the groove. Therefore, the fixing property can be further improved. As described above, the liquid rubber cured material is used as the molding material of the gasket lip, and the hardness (JISA) of the liquid rubber cured material is preferably set to 60 or less (claim 3).

Further, when a pair of gasket lips have different shapes and a flat portion is provided on one of them as in the fuel cell gasket according to the fourth aspect of the present invention, the flat portion is formed by the pair of gasket lips. Since the range of the receiving side is relatively wide depending on the width of the flat portion, the range of the receiving side of the pair of seal portions is set to be relatively large from the median value of the close position of the other gasket lip. Can be expanded.

Further, like the gasket for a fuel cell according to claim 5 or 6 of the present invention, a flat portion is formed on at least one of a pair of gasket lips arranged so as to sandwich the electrolyte membrane portion or the ion exchange membrane. Even if it does, it becomes possible to similarly enlarge the allowable range of the positional deviation and to stabilize the contact of the gasket lip.

When a gasket lip is formed from a cured liquid rubber material as described above, a liquid injection molding device is used as a molding device, and the gasket lip is injected using the liquid injection molding device. At the time of molding, the mold is held such that a gap of 2 mm or less is opened between the upper and lower molds immediately before injection.
Sealing is performed using a sealing material such as a ring (S101, see FIG. 3, the same applies hereinafter). Next, a nozzle touch is performed to close the material inflow port and form a sealed space in the mold that is shielded from outside air (S102). Next, vacuuming is performed through vacuum holes provided at one or a plurality of locations on the mold parting surface. At this time, the nozzle is shut off to prevent the material from being sucked from the nozzle and flowing into the cavity. To prevent the material from flowing in (S10
3). Next, when it is determined that the desired degree of vacuum has been reached, the mold is completely clamped (S104), and a material is injected into the cavity where the degree of vacuum is maintained (S105) to form a gasket lip. 9).

In the method of forming a gasket for a fuel cell according to the ninth aspect, a gasket lip made of a liquid rubber cured material as a low-viscosity material is integrally formed on one or both surfaces of a flat plate. If it is necessary to provide a gasket lip on one side, if the gasket lip is formed on one side at a time, the opposite side will float in the air and may be broken by the molding pressure or generate burrs due to bending. It is also conceivable to provide a convex part on the lower mold to support the groove on the back, but if the groove shape is different on the front and back, it is necessary to manufacture another mold, and in addition to increasing the cost, In view of the fact that the structure becomes very complicated and the height varies due to mold processing tolerance and plate groove depth tolerance, it may be difficult to maintain stable molding. Therefore, in the molding method according to the tenth aspect of the present invention, the gasket lip is integrally formed on both surfaces of the flat plate at the same time through the through holes by providing through holes that are opened on both surfaces of the flat plate. A through hole is formed in the bottom surface of the groove provided on both sides of the plate, and the gasket lip is integrally formed in both grooves simultaneously through the through hole.

The fuel cell gasket according to claim 7 of the present invention is as follows.

That is, in the gasket for a fuel cell according to the first aspect of the present invention, a gasket lip is directly formed on a flat plate, and a hem width larger than the lip width is provided as a measure for preventing lateral displacement. It is said that a gasket is formed so as to cover it by forming a groove on the flat plate and bonding processing, but if such a large hem width is provided, it will waste material and space. Is inevitable. In addition, regarding the holding by the adhesive, the effect of the adhesive on the power generation efficiency is currently unknown, and considering the adverse effects of long-term use, a gasket that satisfies the performance without performing the bonding process is desired. . In addition, when a gasket lip is formed so as to cover the flat plate with a groove for preventing lateral displacement and to cover the groove, the strength of the plate is reduced by this, and in addition, when the assembling is performed according to the depth of the groove. Since the contact pressure is reduced, it is necessary to form a gasket lip that is larger in anticipation of the contact pressure. When the gasket is incorporated, the gasket is further strained, and the durability may be reduced. Therefore, in the gasket for a fuel cell according to claim 7 of the present invention, a projection is provided along the lip line of the flat plate, and the projection is covered with the gasket lip, thereby preventing misalignment and reducing the amount of distortion. The seal surface pressure was ensured and durability was ensured. Further, it is also possible to apply an adhesive as needed like the gasket according to claim 8 and form a gasket lip so as to cover the adhesive. As the projection, a triangular or trapezoidal cross section in which a gap between the projection and the counterpart material at the time of assembly is 0.2 mm or more is preferable, and such a projection is formed by a gasket lip having a thickness of 1.0 mm or less. It is preferred to cover.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

First Embodiment FIG. 1 shows a liquid injection molding apparatus 11 used for carrying out a method of molding a gasket according to this embodiment. The liquid injection molding apparatus 11 includes a main agent tank 12, a colorant tank 13, and a hardening agent. The molding material supplied from the agent tank 14 to the injection device 16 via the material supply plunger 15 is injected into the mold 17 from the injection device 16 to form a gasket (also referred to as a gasket lip or a gasket main body). . The injection device 16 includes a screw 20 driven by the operation of the hydraulic motor 18 and the injection cylinder 19, and an injection cylinder 21 in which the screw 20 is inserted.
And a shut-off valve 23 for preventing inflow of molding material into a nozzle 22 at the tip of the injection cylinder 21.
Are arranged so as to be freely opened and closed. Also, in the mold 17,
A vacuum evacuation device 24 composed of a vacuum pump is connected.

FIG. 2 shows the details of the mold 17, and includes an upper platen 25, a heat insulating plate 26, an upper heating plate 27, and an upper die 2.
8, a middle mold 29, a lower mold 30, a lower heating plate 31, a heat insulating plate 32, and a lower platen 33 are stacked in this order. Upper mold 2
The parting surfaces 34 of the middle mold 29 and the middle mold 29 are sealed by an O-ring 35 mounted on the mounting groove 29a on the upper surface of the middle mold 29. These O-rings 3 are sealed by an O-ring 37 attached to the
The closed space 38 sealed by the vacuum pumps 5 and 37 is evacuated by the evacuation device 24. Further, a cavity space 39 is provided on the upper surface of the lower mold 30, and is formed on the upper surface (one surface) of a planar plate-like porous carbon material (also referred to as a plate or a planar plate) 40 which is fixed in advance in the cavity space 39. Groove (also referred to as processing groove) 40
a or a recess is filled with a molding material from the injection device 16 via the sprue 41, the runner 42 and the gate 43 to form a gasket (also referred to as a gasket lip), and this gasket is integrated with the carbon material 40 simultaneously with the molding. Is done. The carbon material 40 is, specifically, the collector electrode (separator) 2 of the fuel cell, the ion exchange membrane 3 sandwiched therebetween, or the membrane fixed reaction electrode 4 fixed to the ion exchange membrane 3 as described above. As these materials, graphite or the like may be used in addition to carbon. The groove portion 40a is intended to enhance the adhesive strength of the gasket and prevent displacement, and is not necessarily provided when the adhesion between the carbon material 40 and the gasket can be secured or when there is no risk of displacement due to internal pressure during use. Not necessary.

FIG. 3 shows a control flow of the injection molding. In the mold clamping step, first, the mold clamping is temporarily stopped at a predetermined position (S101). During the temporary stop of the mold clamping, the distance between the molds is kept constant by using the holding means of the mold clamping position.
7 is set so that the upper and lower molds 28, 29, and 30 come into contact with each other, and the distance between the parting surfaces 34 and 36 becomes 2 mm or less, so that outside air does not flow into the closed space 38 in the next vacuuming step. . Then, when the temporary stop of the mold clamping is completed, the nozzle 22 is advanced, and the upper mold 2 is moved.
8 (S102). The nozzle touch force needs to be set to such an extent that no leakage occurs during the evacuation of the cavity space 39. In general, the nozzle touch force should be 2 kN or more.
Other than the flow path connected to 4, it is completely shut off from outside air.

After the nozzle touch pressure has increased and the limit switch has been activated, or after a predetermined time has elapsed from the start of advancement of the nozzle 22, the evacuation device 24 is activated,
The evacuation is started (S103). In order to prevent the material from being sucked from the nozzle 22 and flowing into the cavity 39 during evacuation, the shut-off valve is provided in the nozzle 22 as described above, and the valve is closed.

When a preset elapsed time (for example, 15 seconds or less) or a preset vacuum degree (for example, 10 Torr or less) is reached from the start of evacuation, the mold is clamped by high pressure (S104). At this time, the high mold clamping pressure is desirably set to a pressure that is equal to or less than the compressive breaking strength of the carbon material 40, and that does not cause the carbon material 40 to break even when a filling pressure is applied, and does not cause burr leakage. . For example, a groove 40a (width 3.0 mm, depth 0.1 mm) is formed on the surface of a resin-impregnated carbon material (Toyo Carbon IKC-33) 40 which is cut into a shape and thickness (2 mm) suitable for a fuel cell separator. 3 mm) is desirably suppressed to 10 kgf / mm ² or less.

The molding material has an uncured viscosity of 15%.
0 Pa · s (25 ° C), hardness after curing (JIS A) 2
A liquid rubber cured product of No. 0, for example, liquid silicone rubber KE1950-20 (A.B) manufactured by Shin-Etsu Chemical Co., Ltd. is suitable, and the temperature at which curing does not proceed in the injection cylinder 21, that is, 25 in the embodiment.
C. or lower, and a curing temperature 12 at which a desired cured product is obtained.
A cured product is obtained by injecting into a mold whose temperature is controlled at 0 ° C. to 180 ° C., in the example, 150 ° C. The injection pressure at this time is 200 kgf / cm ^{2 in} the example, and the curing time is 150 seconds.

The gasket formed as described above is made of a flat plate-shaped porous carbon material 40 such as the collector electrode 2, the ion exchange membrane 3, or the membrane fixed reaction membrane 4.
Since the gasket made of a low-viscosity material is integrally formed in the groove 40a formed on the surface of the seal, the thickness of the seal portion which has been conventionally suspended, the assembling property is improved, the displacement is prevented, and the low surface is reduced. Pressure and uniform surface pressure can be realized, the number of parts can be reduced, misalignment can be prevented under pressurized conditions during use after assembly, product dimensional accuracy can be stabilized, and assembly defects can be reduced. , Prevents malfunctions and instability due to forgetting to assemble, Reduces molding defects, Stable molding of gaskets, Improves sealability, Simplifies mold structure, Reduces molding process, Reduces bonding process, Reduces cost, Cycle time Can be reduced, and burr leakage can be reduced.

Second Embodiment--In another embodiment shown in FIG. 4, grooves 40a and 40b are formed on the upper and lower surfaces of a planar plate-like porous carbon material 40 previously set in a cavity space 39 so as to correspond to each other. 5A, the grooves 40a,
40b are communicated with each other via a through hole (also referred to as a communication hole) 40c that opens in the bottom surface of each groove 40a, 40b. For example, a plurality of through holes 40 having a diameter of 1 mm are formed at intervals of 10 to 20 mm.

Therefore, when the gasket molding material is supplied to the carbon material 40, as shown in FIG. 3B, the two groove portions 40a, 40b are formed through the through holes 40c.
At the same time, the gaskets 7 and 8 are integrally formed, thereby reducing the thickness of the seal portion, improving the assemblability, preventing misalignment, lowering the surface pressure, and making the surface pressure uniform, which has been a problem. The number of parts can be reduced, misalignment can be prevented under pressurized conditions during use after assembly, product dimensional accuracy can be stabilized, assembly errors can be reduced,
Prevents functional instability due to forgetting to assemble, reduces molding defects, stabilizes molding of gaskets, improves sealability, simplifies mold structure, reduces molding processes, direct molding of gaskets on both sides of thin plate, bonding process Reduction, cost reduction, cycle time reduction, plate crack prevention, burr leakage reduction, and the like can be realized.

Each of the gaskets 7 and 8 has a groove 40.
a, 40b, and sealing portions 7b, 8b protruding from the grooves 40a, 40b and coming into close contact with the mating material.
It is molded integrally with the cured rubber material 9 in the area c. Other configurations, functions, and effects of the molding method according to this embodiment are the same as those of the first embodiment. Also, the grooves 40a, 4
The same applies to the case where 0b may be omitted. In this case, the through holes 40c are opened directly on the upper and lower surfaces of the carbon material 40.

Third Embodiment FIG. 6 shows a cross section of a gasket for a fuel cell according to a third embodiment of the present invention. This gasket is configured as follows.

That is, first, an electrolyte membrane 55 is disposed between a pair of electrodes (also referred to as outer electrodes) 52 and 53, and an electrode (also referred to as an inner electrode) is provided between each of the electrodes 52 and 53 and the electrolyte membrane 55. 59, 60 are arranged, and the electrode 52, the electrode 59, the electrolyte membrane 55, and the electrode 6 are provided.
The fuel cell 51 is formed of a five-layer stack in which the zeros and the electrodes 53 are arranged in this order.

Each of the pair of electrodes 52 and 53 corresponds to the above-described collector electrode (separator), is formed of a carbon plate, and has a thickness t _1.
Is formed in an actual size of about 1 to 2 mm.

The electrolyte membrane 55 corresponds to the above-mentioned ion exchange membrane, and has an electrolyte membrane protection film 56 combined at its planar end, and a combination of the electrolyte membrane 55 and the electrolyte membrane protection film 56. The electrolyte membrane 54
Are formed. The electrolyte membrane protective film 56 includes the electrolyte membrane 5
5 sandwiching the planar end of the pair 5
The pair of components 57 and 58 are respectively composed of laminated portions 57a and 58a that are laminated to each other, and sandwiching portions 57b and 58 that sandwich the planar end of the electrolyte membrane 55.
b. Laminate portions 57a of the pair of components 57 and 58, the thickness _{t 2} of the electrolyte membrane protective film 56 in 58a is formed enough 0.1~0.2mm to scale.

The electrodes 59 and 60 correspond to the above-mentioned membrane-immobilized reaction electrodes, respectively, and are formed of carbon so as to form a gas flow path. The thickness t3 of the _three- layered laminate including the pair of electrodes 59 and 60 and the electrolyte membrane 55 is formed to be about 0.5 to 1.5 mm in actual size.

Gaskets (also referred to as gasket lips or sealing materials) 61, 62 made of a low-viscosity material are integrally formed on the opposing surfaces of the pair of electrodes 52, 53 so as to correspond to each other. , 6
2, a sealing portion is formed by sandwiching the electrolyte membrane protective film 56 of the electrolyte membrane portion 54 in the laminated portions 57a, 58a of the pair of components 57, 58 without bonding.

As shown in an enlarged view in FIG. 7, one of the pair of gaskets 61, 62 has a flat portion (also referred to as a flat portion) 61a formed at the tip thereof. 61a has a predetermined width _{w 1.} And the other gasket 62, the is formed a distal end portion 62a as convex or triangular cross-section throughout and is formed on an arc-shaped cross section, the plane of one of the gasket 61 the width w ₂ of the tip portion 62a width parts 61a _{w 1}
It is formed smaller than.

Each of the gaskets 61 and 62 is formed of low hardness silicone rubber.

The gasket having the above structure is obtained by integrally forming gaskets 61 and 62 made of silicone rubber which is a cured liquid rubber on the surfaces of a pair of electrodes 52 and 53 which are a flat plate-shaped porous material. , Because the rubber is integrated with the plate at the same time as molding
It is possible to reduce the thickness of the seal part, improve the assemblability, prevent misalignment, reduce the surface pressure and make the surface pressure uniform, and reduce the number of parts, use after assembly Prevents misalignment under pressurized conditions during operation, stabilizes product dimensional accuracy, reduces assembly defects, prevents malfunctions and instability due to forgetting to assemble, reduces molding defects, stable gasket molding, improves sealing Thus, simplification of the mold structure, reduction in the number of molding steps, reduction in the number of bonding steps, reduction in cost, reduction in cycle time, reduction in burr leakage, and the like can be realized.

Further, since the pair of gaskets 61 and 62 have different cross-sectional shapes and one of the gaskets 61 has the flat portion 61a, the flat portion 61a is provided.
Is the receiving side of the pair of seal portions formed by the pair of gaskets 61 and 62, and the range of the receiving side is the flat portion 61.
It is relatively widely set the width w ₁ of a. Therefore, the other material of the other gasket 62 (the electrolyte membrane 5
4) The allowable range of the positional deviation from the median of the close position to the position 4) can be expanded, so that the necessary sealing property can be sufficiently secured even if the positional deviation is somewhat large.

Fourth Embodiment As shown in FIG. 8, in addition to the above-described structure, a part of both gaskets 61, 62 is provided on the surface of the electrodes 52, 53, respectively.
In this case, the distance between the pair of electrodes 52 and 53 can be shortened, so that the stack or the fuel cell can be made compact in the thickness direction. Can be.

Fifth Embodiment A fuel cell gasket according to the third and fourth embodiments has a structure in which an electrolyte membrane portion 54 is sandwiched between a pair of gaskets 61 and 62, The electrolyte membrane 55 itself, that is, the ion exchange membrane 55 itself may be sandwiched between the gaskets 61 and 62, and this example is shown in FIGS. 9 and 10 as a fifth embodiment.

That is, the fuel cell gasket shown in FIGS. 9 and 10 is configured as follows.

That is, first, an ion exchange membrane 55 corresponding to the electrolyte membrane 55 in the third and fourth embodiments is disposed between a pair of electrodes (also referred to as outer electrodes) 52, 53, and each electrode 52 , 53 and the ion exchange membrane 55 (also referred to as inner electrodes), respectively.
9, 60 are arranged, and these electrodes 52, 5
9, a fuel cell 51 composed of a five-layer laminate in which the ion exchange membrane 55, the electrode 60, and the electrode 53 are arranged in this order.

Each of the pair of electrodes 52 and 53 corresponds to the above-mentioned collector electrode (separator), and is formed of a carbon plate, and has a thickness of about 1 to 2 mm in actual size. .

Each of the electrodes 59 and 60 corresponds to the above-mentioned membrane fixed reaction electrode, and is formed of carbon so as to form a gas flow path. The thickness of the three-layer laminated body including the pair of electrodes 59 and 60 and the ion exchange membrane 55 is formed to be about 0.5 to 1.5 mm in actual size.

Gaskets (also referred to as gasket lips or sealing materials) 61 and 62 made of a low-viscosity material are integrally formed on the opposing surfaces of the pair of electrodes 52 and 53 so as to correspond to each other. , 6
The sealing portion is formed by sandwiching the ion exchange membrane 55 in a non-bonding manner between the two.

As shown in FIG. 10 in an enlarged manner, one of the pair of gaskets 61, 62 has a flat portion (also referred to as a flat portion) 62 at its tip.
b is formed with, the flat portion 61b is predetermined width w ₃
It has. The other gasket 61 on the upper and lower sides in the figure
Has its distal end portion 61b is formed as one of the convex section or triangular cross-section throughout and is formed on an arc-shaped cross section, the width of the flat portion 62b of one of the gasket 62 the width w ₄ of the distal end 61b It is formed to be smaller than w _3.

Each of the gaskets 61 and 62 is formed of low hardness silicone rubber.

The gasket having the above structure is obtained by integrally forming gaskets 61 and 62 made of silicone rubber which is a cured liquid rubber on the surfaces of a pair of electrodes 52 and 53 which are a flat plate-shaped porous material. , Because the rubber is integrated with the plate at the same time as molding
It is possible to reduce the thickness of the seal part, improve the assemblability, prevent misalignment, reduce the surface pressure and make the surface pressure uniform, and reduce the number of parts, use after assembly Prevents misalignment under pressurized conditions during operation, stabilizes product dimensional accuracy, reduces assembly defects, prevents malfunctions and instability due to forgetting to assemble, reduces molding defects, stable gasket molding, improves sealing Thus, simplification of the mold structure, reduction in the number of molding steps, reduction in the number of bonding steps, reduction in cost, reduction in cycle time, reduction in burr leakage, and the like can be realized.

Since the flat portion 62b is provided on one of the pair of gaskets 61 and 62, the flat portion 62b is a receiving side of the pair of seal portions formed by the pair of gaskets 61 and 62. Te, the range of the receiving side is relatively widely set the width w ₃ of the planar portion 62b. Therefore, the allowable range of the positional deviation from the median of the close position of the other gasket 62 with respect to the counterpart material (ion exchange membrane 55) can be expanded, so that even if the positional deviation is somewhat large, the necessary sealing property is sufficiently increased. Can be secured. However, from the viewpoint of sealing properties improve, because it is preferable contact surface pressure is as large as possible with respect to the mating member of the gasket 62 (ion exchange membrane 55), the width w ₃ of the flat portion 62b is required to eliminate the positional deviation It is preferred to stay within the range.

The structure of the gasket according to the fifth embodiment can be added or changed as follows.

The upper and lower gaskets 61 and 62 in FIGS. 9 and 10 are provided in the grooves 52 a and 53 a formed on the surfaces of the electrodes 52 and 53, respectively, but the grooves 52 a and 53 a are eliminated. Gasket 6
1 and 62 are provided directly on the surfaces of the electrodes 52 and 53.

The cross-sectional shape of the seal portion of the gasket 62 having the flat portion 62b on the upper side in FIGS. 9 and 10 is trapezoidal or substantially trapezoidal, whereas the cross-sectional shape is rectangular as shown in FIG. The gasket 62 is formed in a flat plate shape. In this case, the flat portion 62b is provided over the entire width of the gasket 62.

The cross-sectional shape of the sealing portion of the lower gasket 61 in FIGS. 9 and 10 is convex, triangular or substantially triangular, whereas the cross-sectional shape is changed to the upper side as shown in FIG. And a trapezoid or substantially trapezoid similar to the gasket 62 of FIG. Therefore, in this case, the cross-sectional shapes of the upper and lower gaskets 61 and 62 are respectively trapezoidal or substantially trapezoidal, and the two gaskets 61 and 62 are provided with flat portions 61a and 62b, respectively. The cross-sectional shape may be square or rectangular as described above.

Further, the contents of the changes made by this and
The third and fourth embodiments in which the electrolyte membrane portion 54 is interposed between the pair of gaskets 61 and 62 can be applied as they are.

Sixth embodiment ...

That is, first, a gasket line (also referred to as a gasket lip line) is formed on the surface of a flat plate 71 as a collector electrode, an ion exchange membrane or a membrane-fixed reaction electrode made of porous carbon, graphite, a conductive phenol resin, a magnesium alloy or the like. A projection 72 is integrally formed along the line, and a gasket 73 made of a cured liquid rubber having a hardness (JIS A) of 60 or less is formed so as to cover the projection 72 without using an adhesive or with an adhesive. It is integrally molded using.

The projection 72 has a substantially triangular or trapezoidal cross section, and is provided over the entire length of the gasket line. The gasket 73 has a ridge 73a having a substantially triangular or substantially arcuate cross section which covers the projection 72 and contacts the mating member 74 when assembling to form a sealing action, and is provided on both sides of the ridge 73a, respectively. A flat hem 73b having a lower height than the ridge 73a is integrally formed. In addition, the dimensions of each part are set based on the following criteria.

The width (maximum width at the bottom) w of the projection 72
₁₁ : 2 mm or less Total width w _{12 of} gasket 73: 2 to 5 mm Width w ₁₃ of crest 73 a of gasket 73: 1 to 5 mm Thickness t ₁₄ of skirt 73 b of gasket 73: 1 mm or less Crest 73 a from upper surface of skirt 73 b Height h ₁₅ to the top:
The thickness _{t 16} of 0.2~2mm following crest 73a (minimum width in the crest width direction center): width of the recess 75 formed in the mating member 74 1mm or less gasket contacts during assembly _{w 17:} Gasket full width The size of w ₁₂ or more The depth d _{18 of the} concave portion 75: 1 mm or less

The dimensions of these parts are such that the vertical spacing between the projection 72 and the mating member 74 at the time of assembly is 0.2 to 1.0 mm, and the gap due to this spacing has a thickness of 1.0 mm or less. Are calculated so that the gasket 73 is filled and compressed to perform a sealing action, and are respectively set as specific numerical values.

In the gasket having the above configuration,
A liquid rubber cured product having a hardness (JIS A) of 60 or less is formed on the surface of a flat plate 71 as a collector electrode, an ion exchange membrane or a membrane-fixed reaction electrode made of porous carbon, graphite, a conductive phenol resin, a magnesium alloy, or the like. Since the gasket 73 is formed integrally without using an adhesive or using an adhesive, the sealing portion, which has been conventionally a problem, can be made thinner, assemblability can be improved, misalignment can be prevented, Low surface pressure and uniform surface pressure can be achieved, reduction of the number of parts, prevention of misalignment under pressurized conditions during use after assembly, stabilization of product dimensional accuracy, assembly failure Reduction, prevention of functional instability due to forgetting to assemble, reduction of molding failure, stable molding of gasket, improvement of sealability, simplification of mold structure, reduction of molding process, reduction of bonding process It is possible to realize reduction in cost, reduction in cost, reduction in cycle time, reduction in burr leakage, and the like.

A projection 72 is integrally formed along a gasket line on the surface of a flat plate 71 as a collector electrode, an ion exchange membrane or a membrane-fixed reaction electrode made of porous carbon, graphite, conductive phenol resin or magnesium alloy. Since the gasket 73 made of a cured liquid rubber having a hardness (JIS A) of 60 or less is formed integrally with the projection 72 without using an adhesive and using an adhesive, The projection 72 is the gasket 7
By supporting the gasket 3, displacement of the gasket 73 can be more effectively prevented. Gasket 73
By limiting the amount of compression, the sealing surface pressure can be sufficiently ensured with a small amount of distortion, and the durability of the gasket can be improved by providing the projection 72 and eliminating the groove for preventing lateral displacement. . Further, when the gasket 73 is held only by the support by the projection 72 without using the adhesive, the gasket can be used without worrying about the adverse effect on the power generation efficiency due to the use of the adhesive. be able to.

The structure of the gasket according to the sixth embodiment can be added or changed as follows.

That is, in the gasket according to the above embodiment, the concave portion 75 is formed in the mating member 74 with which the gasket 73 comes into contact at the time of assembling because the mating member 74 and the surfaces 71a, 74a of the flat plate 71 are in contact with each other. This is for setting the interval of 0.2 mm or more between the projection 72 and the mating member 74 when positioning them together, to limit the amount of compression of the gasket 73. Therefore, instead of providing the concave portion 75 in the mating member 74 as means for limiting the amount of compression, as shown in FIG. 14, a protruding or stepped spacer portion 76 is provided in the mating member 74, and the spacer portion 76 is formed.
May be brought into contact with the surface 71a of the flat plate 71. Further, as shown in FIG.
May be provided on the flat plate 71 side, and as shown in FIG. 16, a projecting or stepped spacer portion 76 may be provided on the flat plate 71 side.

Seventh embodiment ...

Next, FIG. 17 shows a cross section of a gasket for a fuel cell according to a seventh embodiment of the present invention. This gasket is configured as follows.

First, a gasket line (also referred to as a gasket lip line) is formed on the surface of a flat plate 71 as a collector, ion exchange membrane or membrane-fixed reaction electrode made of porous carbon, graphite, conductive phenol resin or magnesium alloy. A projection 72 is integrally formed along the line, and a gasket 73 made of a cured liquid rubber having a hardness (JIS A) of 60 or less is formed so as to cover the projection 72 without using an adhesive or with an adhesive. It is integrally molded using.

The projection 72 has a substantially triangular or trapezoidal cross section, and is provided over the entire length of the gasket line. The gasket 73 is formed in a substantially triangular or substantially arcuate cross-section so as to cover the projection 72 and to make contact with the mating member 74 at the time of assembly so as to perform a sealing action. The skirt portion 73b in the sixth embodiment is provided. Not been. In addition, the dimensions of each part are set based on the following criteria.

The width (maximum width at the bottom) w of the projection 72
₁₁ : 2 mm or less Total width w _{12 of the} gasket 73: 2 to 5 mm Total height h _{19 of the} gasket 73: 2 mm or less Thickness t _{16 of the} gasket 73 (minimum width at the center of the crest width direction): 1 mm or less The gasket comes into contact at the time of assembly. The width w _{17 of the} concave portion 75 formed in the mating member 74: a size not less than the total width w _{12 of the} gasket The depth d _{18 of the} concave portion 75: 1 mm or less

The dimensions of these parts are such that the vertical interval between the projection 72 and the mating member 74 at the time of assembly is 0.2 to 1.0 mm, and the gap due to this interval is 1.0 mm or less in thickness. Are calculated so that the gasket 73 is filled and compressed to perform a sealing action, and are respectively set as specific numerical values.

In the gasket having the above configuration,
A liquid rubber cured product having a hardness (JIS A) of 60 or less is formed on the surface of a flat plate 71 as a collector electrode, an ion exchange membrane or a membrane-fixed reaction electrode made of porous carbon, graphite, a conductive phenol resin, a magnesium alloy, or the like. Since the gasket 73 is formed integrally without using an adhesive or using an adhesive, the sealing portion, which has been conventionally a problem, can be made thinner, assemblability can be improved, misalignment can be prevented, Low surface pressure and uniform surface pressure can be achieved, reduction of the number of parts, prevention of misalignment under pressurized conditions during use after assembly, stabilization of product dimensional accuracy, assembly failure Reduction, prevention of functional instability due to forgetting to assemble, reduction of molding failure, stable molding of gasket, improvement of sealability, simplification of mold structure, reduction of molding process, reduction of bonding process It is possible to realize reduction in cost, reduction in cost, reduction in cycle time, reduction in burr leakage, and the like.

Also, a projection 72 is integrally formed along the gasket line on the surface of a flat plate 71 as a collector electrode, an ion exchange membrane or a membrane-fixed reaction electrode made of porous carbon, graphite, conductive phenol resin or magnesium alloy. So as to cover the projection 72,
Since the gasket 73 made of a liquid rubber cured product having a hardness (JIS A) of 60 or less is integrally formed without using an adhesive and using an adhesive, the projection 72 supports the gasket 73. The displacement of the gasket 73 can be more effectively prevented. Gasket 7
By limiting the amount of compression of No. 3, the sealing surface pressure can be sufficiently secured with a small amount of distortion, and the durability of the gasket can be improved by providing the projection 72 and eliminating the groove for preventing lateral displacement. it can. Further, when the gasket 73 is held only by the support by the projection 72 without using the adhesive, the gasket can be used without worrying about the adverse effect on the power generation efficiency due to the use of the adhesive. be able to. Further, since the gasket 73 is not provided with a skirt portion and the gasket 73 is formed only by mountain portions having a substantially triangular or substantially arc-shaped cross section, the yield of the molding material can be improved, and the mounting space can be increased. Can be reduced.

The configuration of the gasket according to the seventh embodiment can be added or changed as follows.

That is, in the gasket according to the above embodiment, the concave portion 75 is formed in the mating member 74 with which the gasket 73 comes into contact at the time of assembly, because the mating member 74 and the surfaces 71a, 74a of the flat plate 71 are in contact with each other. This is for setting the interval of 0.2 mm or more between the projection 72 and the mating member 74 when positioning them together, to limit the amount of compression of the gasket 73. Therefore, instead of providing the concave portion 75 in the mating member 74 as a means for limiting the amount of compression, as shown in FIG. 18, a protruding or stepped spacer portion 76 is provided in the mating member 74, and the spacer portion 76 is formed.
May be brought into contact with the surface 71a of the flat plate 71. Also, as shown in FIG.
May be provided on the flat plate 71 side, and as shown in FIG. 20, a projecting or stepped spacer portion 76 may be provided on the flat plate 71 side.

[0081]

The present invention has the following effects.

First, in the gasket according to the present invention having the above structure, a gasket lip made of a cured liquid rubber is integrally formed on the surface of the flat plate or the electrode or the groove formed on the surface. As a result, it is possible to reduce the thickness of the seal portion, improve the assemblability, prevent misalignment, reduce the surface pressure and make the surface pressure uniform, and reduce the number of parts, which has been a problem in the past. , Prevents misalignment under pressurized conditions during use after assembly, stabilizes product dimensional accuracy, reduces assembly failure, prevents malfunction failure due to forgetting to assemble, reduces molding failure, improves sealing Thus, it is possible to reduce the number of molding steps, the number of bonding steps, the cost, and the burr leakage.

In addition, in the gasket according to the fourth aspect of the present invention having the above structure, the pair of gasket lips have different cross-sectional shapes, and one of the gasket lips has a flat portion. As a result, it is possible to expand the allowable range of the misalignment from the median of the close position of the other gasket lip to the mating material, thereby sufficiently securing the necessary sealing performance even if the misalignment is somewhat large. Can be.

Further, according to claim 5 of the present invention having the above configuration,
Or a gasket according to 6, wherein at least one of a pair of gasket lips arranged so as to sandwich the electrolyte membrane portion or the ion exchange membrane has a flat portion having a predetermined width in contact with the electrolyte membrane portion or the ion exchange membrane. Is formed, it is also possible to expand the allowable range of positional deviation from the median of the close position of the other gasket lip to the mating material, and thereby, even if the positional deviation is somewhat large, the necessary sealing property is improved. It can be sufficiently secured. When both gasket lips are provided with a flat portion, the contact state is stabilized, so that the necessary sealing properties can be sufficiently secured.

Further, according to the present invention having the above structure,
Or, in the gasket according to 8, a projection is provided along the gasket lip line on the surface of a flat plate made of porous carbon, graphite, conductive phenol resin, magnesium alloy, or the like, and the gasket lip is integrated so as to cover the projection. Since the projections support the gasket lip, the gasket lip can be more effectively prevented from being displaced. In addition, since the compression amount of the gasket lip is limited, the sealing surface pressure can be sufficiently secured with a low distortion amount, and the durability of the gasket is improved by providing a protrusion and eliminating the groove portion for preventing lateral displacement. be able to.

Further, according to the ninth aspect of the present invention having the above configuration,
In the method of forming a gasket according to 10 or 10, the gasket can be formed stably, and the structure of the mold apparatus is relatively simple, and the cycle time can be relatively short.

Further, in the method of forming a gasket according to the tenth aspect of the present invention having the above-described structure, it is possible to reduce the thickness of the seal portion and improve the assemblability, which has been a conventional problem.
Prevents misalignment, reduces surface pressure and makes surface pressure uniform, reduces the number of parts, prevents misalignment under pressure conditions during use after assembly, and stabilizes product dimensional accuracy , Reduction of assembly failure, prevention of functional instability due to forgetting to assemble, reduction of molding failure, stable molding of gasket, improvement of sealability, simplification of mold structure, reduction of molding process, gasket on both sides of thin plate It is possible to reduce the number of steps of the direct molding, the bonding process, the cost, the cycle time, the prevention of plate cracking and the reduction of burr leakage.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a liquid injection molding apparatus used for performing a gasket molding method according to a first embodiment of the present invention.

FIG. 2 is a detailed explanatory view of a mold in the apparatus.

FIG. 3 is a control flowchart of the apparatus.

FIG. 4 is a detailed explanatory view of a mold in a liquid injection molding apparatus used for performing a gasket molding method according to a second embodiment of the present invention.

FIG. 5A is a cross-sectional view of a main part of a porous material before a gasket is formed, and FIG. 5B is a cross-sectional view of a main part of the porous material after a gasket is formed.

FIG. 6 is a sectional view of a gasket according to a third embodiment of the present invention.

FIG. 7 is an enlarged view of a main part of FIG. 6;

FIG. 8 is a sectional view of a main part of a gasket according to a fourth embodiment of the present invention.

FIG. 9 is a sectional view of a gasket according to a fifth embodiment of the present invention.

FIG. 10 is an enlarged view of a main part of FIG. 9;

FIG. 11 is a sectional view of an essential part showing an example of a structural change of the gasket.

FIG. 12 is a sectional view of an essential part showing an example of a structural change of the gasket.

FIG. 13 is a sectional view of a main part of a gasket according to a sixth embodiment of the present invention.

FIG. 14 is a cross-sectional view of a main part showing an example of a structure change of the gasket.

FIG. 15 is a sectional view of an essential part showing an example of a structural change of the gasket.

FIG. 16 is a sectional view of an essential part showing an example of a structure change of the gasket.

FIG. 17 is a sectional view of a main part of a gasket according to a sixth embodiment of the present invention.

FIG. 18 is a sectional view of an essential part showing an example of a structural change of the gasket.

FIG. 19 is a sectional view of a main part showing an example of a structure change of the gasket.

FIG. 20 is an essential part cross sectional view showing a modification example of the structure of the gasket.

FIG. 21 is an explanatory diagram showing a configuration example of a fuel cell.

[Explanation of symbols]

1,51 Fuel cell 2 Collector electrode 3 Ion exchange membrane 4 Membrane fixed reaction electrode 5 Rubber plate 6 Foam sponge layer 7,8,61,62,73 Gasket (gasket lip) 7a, 8a Filling part 7b, 8b Sealing part 9 Rubber cured product in through hole 11 Liquid injection molding device 12 Main agent tank 13 Colorant tank 14 Hardener tank 15 Material supply plunger 16 Injection device 17 Mold 18 Hydraulic motor 19 Injection cylinder 20 Screw 21 Injection cylinder 22 Nozzle 23 Shut Off valve 24 Vacuum evacuation device 25 Upper platen 26, 32 Insulation board 27 Upper heating board 28 Upper mold 29 Middle mold 29a, 30a Mounting groove 30 Lower mold 31 Lower heating board 33 Lower platen 34, 36 Parting surface 35, 37 O-ring 38 Closed space 39 Cavity space 40 Flat plate-shaped porous Bon material 40a, 40b, 52a, 53a Groove 40c Through hole 41 Sprue 42 Runner 43 Gate 52, 53, 59, 60 Electrode 52a, 53a Groove 54 Electrolyte membrane part 55 Electrolyte membrane (ion exchange membrane) 56 Electrolyte membrane protective membrane 57, 58 Electrolyte membrane protective film constituent parts 57a, 58a Laminated part 57b, 58b Nipping part 61a, 61c, 62b Flat part 61b, 62a Tip part 71 Flat plate 72 Projection 73a Mountain part 73b Hem part 74 Counterpart material 75 Depressed part 76 Spacer part

 ──────────────────────────────────────────────────続 き Continued on the front page (31) Priority claim number Japanese Patent Application No. 11-293988 (32) Priority date October 15, 1999 (Oct. 15, 1999) (33) Priority claim country Japan (JP) (72) Inventor Yuichi Kuroki 4-3-1 Tsujido Shinmachi, Fujisawa-shi, Kanagawa F-term in NOK Co., Ltd. (reference) 5H026 AA06 BB00 BB01 BB02 BB04 CC03 CX05 CX07 CX08 EE05 EE06 EE08 EE18 HH00

Claims (10)

[Claims] 1. A gasket lip made of a cured liquid rubber is integrally formed on a surface of a flat plate made of porous carbon, graphite, a conductive phenol resin, a magnesium alloy or the like or a groove formed on the surface. Gasket for fuel cells. 2. The gasket for a fuel cell according to claim 1, wherein the flat plate is a collecting electrode, an ion exchange membrane, or a membrane-fixed reaction electrode. 3. The gasket for a fuel cell according to claim 1, wherein the cured liquid rubber has a hardness (JIS A) of 60 or less. 4. A cross-section of a pair of said gasket lips having a gasket lip made of a liquid rubber cured product integrally formed on a surface of an electrode or a groove provided on said surface, and sandwiching an electrolyte membrane portion. A gasket for a fuel cell, wherein the gasket lip is formed so as to have different shapes, and one of the gasket lips is formed with a flat portion having a predetermined width in contact with the electrolyte membrane portion. 5. A gasket lip comprising a liquid rubber cured product integrally formed on a surface of an electrode or a groove provided on the surface, and a gasket lip disposed so as to sandwich an electrolyte membrane. A gasket for a fuel cell, wherein a flat portion having a predetermined width is formed on at least one of the gaskets to contact the electrolyte membrane portion. 6. A pair of gasket lips having a gasket lip made of a liquid rubber cured product integrally formed on a surface of an electrode or a groove provided on the surface, and arranged to sandwich an ion exchange membrane. A gasket for a fuel cell, wherein a flat portion having a predetermined width is formed on at least one of the gasket and the ion-exchange membrane. 7. The gasket for a fuel cell according to claim 1, wherein a projection along the gasket lip line is provided on the flat plate, and a gasket lip is formed to cover the projection. 8. The gasket for a fuel cell according to claim 1, wherein a projection along the gasket lip line is provided on the flat plate, an adhesive is applied around the projection, and the gasket lip is formed to cover the area. A gasket for a fuel cell, comprising: 9. A method for forming a gasket for a fuel cell according to claim 1, wherein a gap is provided between the upper and lower molds before the injection, and the gasket lip is injection-molded. Forming a gasket for a fuel cell. 10. The method for forming a gasket for a fuel cell according to claim 9, wherein a through hole is provided which opens on both sides of a flat plate or a bottom surface of a groove provided on the both sides, and the two sides are provided through the through hole. Alternatively, a method of forming a gasket for a fuel cell, wherein a gasket lip is integrally formed in both grooves simultaneously.