JP3952154B2 - Fuel cell components - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a component for a fuel cell that constitutes a component of a fuel cell, and more particularly to an integrated product of a gas diffusion layer and a gasket.
[0002]
[Prior art]
In the polymer electrolyte fuel cell, since the magnitude of the voltage per cell is determined from the chemical reaction, in order to increase the voltage, it is necessary to stack a large number of cells, Each cell requires a gasket for sealing fuel gas and cooling water, and a gasket for a portion that becomes a manifold for gas and cooling water. Therefore, if a single rubber type gasket is used as this gasket, there are inconveniences that many labor and time are required when many cells are stacked.
[0003]
Therefore, currently, a method of previously integrating the separator and the gasket and a method of previously integrating the electrolyte membrane and the gasket are being studied. Further, when it is difficult to integrate the electrolyte membrane and the gasket, a method of integrating the gas diffusion layer and the gasket has been proposed. In this case, the carbon material constituting the gas diffusion layer is mainly used. On the other hand, an integral product is formed by impregnating rubber as a gasket material.
[0004]
However, when the gas diffusion layer is impregnated with rubber in this way, the carbon fiber of the gas diffusion layer is dispersed in the rubber as a result of the impregnation, which increases the permanent compression strain of the gasket. In some cases, problems remain in the durability of the gasket.
[0005]
In addition, according to a US patent filed by Ballard Corporation of Canada, a technique for processing a groove in carbon paper and attaching a gasket along the groove using an adhesive (US Pat. No. 5,284,718), carbon A technique (US Pat. No. 5,176,966) is disclosed in which a groove is formed in carbon paper in a reaction electrode portion (MEA) in which paper and an electrolyte membrane are integrated, and a gasket is integrated along the groove.
[0006]
However, for the former, there are inconveniences that many man-hours and time are required for production due to a large number of assembly steps, and it is difficult to reduce the cost. For the latter, a gasket is molded on the MEA. When a thermosetting rubber material is used, there is a disadvantage that there is a possibility that the electrolyte membrane may be damaged by heat.
[0007]
[Problems to be solved by the invention]
In view of the above, the present invention is capable of suppressing permanent compression strain generated in a gasket in an integrated product of a gas diffusion layer and a gasket used in a fuel cell, and is easy to manufacture and thermosetting. An object of the present invention is to provide a fuel cell component that does not damage the electrolyte membrane due to heat even when a rubber material is used.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a fuel cell component of the present invention has a flat gas diffusion layer having a fiber and a gasket made of rubber disposed endlessly on a plane of the gas diffusion layer. On the plane of the gas diffusion layer, a through hole portion serving as a flow path and a through portion for mounting the gasket are provided, and the through portion penetrates the gas diffusion layer in the thickness direction. And a groove-like connection portion for connecting the inner portion and the outer portion of the groove on the circumference, and the gasket is formed by an injection method, a dispenser method or It is formed into an endless shape along the groove-like through portion by a screen printing method, and a part thereof is impregnated in the gas diffusion layer .
[0009]
In the fuel cell component of the present invention having the above-described configuration, a through portion penetrating the gas diffusion layer in the thickness direction is provided in a groove shape on the plane of the gas diffusion layer in accordance with the planar arrangement of the gasket. Since the gasket is integrally formed with the gas diffusion layer along the groove-shaped through portion, most of the gasket is disposed in the groove-shaped through portion and does not overlap the gas diffusion layer on a plane. become. Therefore, even when the gas diffusion layer has a fiber such as carbon fiber, it is possible to suppress a large amount of the fiber from being mixed into the rubber as the gasket material.
[0010]
In addition, the component of the present invention having the above-described configuration is formed by integrally molding a gasket with respect to the gas diffusion layer using a mold or the like. There is an advantage that it can be done.
[0011]
In addition, since the component of the present invention is formed by integrally molding the gasket with respect to the gas diffusion layer and not by integrally molding the gasket with respect to the electrolyte membrane, the component is not formed when the electrolyte membrane is concerned about heat resistance. There is no risk of damage from heat.
[0012]
The present application includes the following technical matters.
[0013]
That is, in order to achieve the above object, one fuel cell component proposed by the present application or a manufacturing method thereof is as follows:
(1) In the gas diffusion layer and gasket integrated product used in fuel cells, grooves are processed in advance using a Thomson blade, water jet, or laser in the gas diffusion layer where the gasket is integrated, and then the gasket is integrally molded. And
▲ 2 ▼ Gaskets such as non-woven fabric and carbon paper used in gas diffusion layers are processed in advance using a Thomson blade, water jet, or laser cutting method, and the shape is cut into a groove shape according to the shape of the gasket. To do.
[0014]
(3) Embodiments of the invention according to the above items (1) to (2) are as follows.
That is, the gas diffusion layer and gasket used in the polymer electrolyte fuel cell are integrated. The thickness of carbon paper or nonwoven fabric used as the gas diffusion layer is preferably about 0.1 to 0.8 mm. Grooves and flow paths are formed in advance in this gas diffusion layer by die cutting using a Thomson blade or the like, cutting using a water jet, or cutting using a laser. Thereafter, a gasket is formed in the groove using injection, dispenser, or screen printing. As the type of rubber to be molded, silicone rubber, fluorine rubber, EPDM, butyl rubber or the like is suitable. The height of the gasket is about 0.1 to 2 mm, and the hardness is about 10 to 80 degrees. When the component is molded with a mold, there is an advantage that various gasket cross-sectional shapes can be manufactured.
[0015]
(4) According to the above items (1) to (3), the following effects can be obtained.
That is, first, since there is no gas diffusion layer directly under the gasket, the compression set of the gasket can be reduced. Further, when the rubber is integrated with the gas diffusion layer, it can be easily fixed in the mold. Further, since the gasket is not formed on the MEA but is formed only on the carbon paper, it is possible to prevent damage to the electrolyte membrane due to heat at the time of forming the gasket.
[0016]
In addition, about the said component, although there is a possibility that a gasket may shift | deviate partially or remove | deviate from a gas diffusion layer, the reply with respect to this is as follows.
[0017]
That is, since the gas diffusion layer is punched and then positioned in the mold to integrally form the gasket, the gas diffusion layer and the gasket do not shift. In addition, it is preferable to punch out the gas diffusion layer with a dimensional allowance so that even if it is slightly deviated. In addition, because of the integral molding, the gasket and the gas diffusion layer have an impregnated portion, and therefore the possibility that the gasket is detached from the gas diffusion layer is small.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0019]
FIG. 1 is a plan view of a fuel cell component 1 according to an embodiment of the present invention, and an enlarged cross-sectional view taken along line AA is shown in FIG. FIG. 3 is a plan view of a material for forming the gas diffusion layer 2, and FIG. 4 is a plan view of a single product state of the gas diffusion layer 2 in a state where necessary processing such as holes and grooves is applied to the material. Thus, the gasket 6 is integrally formed with the gas diffusion layer 2 in the state of FIG.
[0020]
The component 1 according to this embodiment is an integral part of a gas diffusion layer 2 and a gasket 6 used in a fuel cell, and is configured as follows.
[0021]
That is, first, a gas diffusion layer 2 formed in a flat plate shape by a carbon plate, carbon paper, nonwoven fabric, or the like is provided, and on the plane of the gas diffusion layer 2, a flow path for fuel gas, cooling water, or the like is formed. The hole 3 and the through portion 4 for integrally molding the gasket 6 are formed with a predetermined planar arrangement. The through-hole portion 3 is a hole that penetrates the gas diffusion layer 2 in the thickness direction, and the penetration portion 4 is also a hole that penetrates the gas diffusion layer 2 in the thickness direction. It is provided as a groove on the plane of the gas diffusion layer 2 in accordance with the planar arrangement. Further, when the gasket 6 is disposed endlessly on the plane, the groove-like through portion 4 should be formed as an endless groove in accordance with this, but in this case, a part of the gas diffusion layer is formed in the inner portion of the endless groove. In order to prevent this, bridge-like connecting portions 5 for connecting the inner and outer portions of the endless groove are provided in places around the endless groove.
[0022]
The above description is the state of FIG. 4, and the gasket 6 is integrally formed with the gas diffusion layer 2 of FIG. 4 as shown in FIG. 1, that is, the gasket 6 is diffused along the groove-shaped through portion 4. It is integrally formed with the layer 2. As shown in the sectional view of FIG. 2, the gasket 6 is fully filled in the through portion 4 and protrudes upward from the upper surface of the gas diffusion layer 2 and protrudes downward from the lower surface of the gas diffusion layer 2. The gasket 6 having a cross-sectional shape is formed in an endless shape along the endless groove. The thickness of the gas diffusion layer 2 is about 0.1 to 0.8 mm, and the height of the gasket 6 is about 0.1 to 2 mm. Although not shown, the gasket 6 is partially impregnated with respect to the inner surface of the penetrating portion 4, so that the gasket 6 is configured not to be detached from the gas diffusion layer 2.
[0023]
Next, a method for manufacturing the component 1 having the above configuration will be described.
[0024]
That is, first, a planar gas diffusion layer 2 is prepared as shown in FIG. 3, and then, as shown in FIG. 4, a die-cut method using a Thomson blade or the like, a water jet cut method or a laser cut is applied to the gas diffusion layer 2. The through-hole portion 3 and the through portion 4 are formed by a method or the like. Next, the gas diffusion layer 2 finished as a single product is set in the cavity space of the injection mold, and a gasket 6 is formed by pouring a rubber material. As described above, a part of the rubber material is impregnated into the gas diffusion layer 2 and the both are integrated during the molding. As the type of rubber material, silicone rubber, fluorine rubber, EPDM, butyl rubber or the like is suitable, and the hardness of the molded gasket 6 is preferably about 10 to 80 degrees.
[0025]
According to the component 1 having the above-described configuration, the following operational effects can be achieved.
[0026]
That is, firstly, a through-hole 4 penetrating the gas diffusion layer 2 in the thickness direction is provided as a groove in the gas diffusion layer 2 in accordance with the planar arrangement of the gasket 6. Since the gasket 6 is integrally formed with the gas diffusion layer 2 along the gasket 6, most of the gasket 6 is disposed in the groove-like through portion 4 and does not overlap the gas diffusion layer 2 on a plane. Placed in. Accordingly, since it is possible to suppress a large amount of fibers such as carbon fibers of the gas diffusion layer 2 from being inserted into the rubber as the gasket material, the permanent compression strain generated in the gasket 6 when the component 1 is mounted and used is reduced. Can be suppressed. The gasket 6 shown in the figure is a double-sided gasket as described above, and has a seal lip 6a having a substantially triangular cross section on each of both surfaces, and the seal lip 6a is strongly compressed and deformed when used. The seal lip 6a is disposed at a position substantially in the center of the groove width in the groove-like through portion 4 where the influence of impregnation is small. Therefore, even if the gasket 6 provided with the seal lip 6a having a triangular cross section as described above is strongly compressed during use, it does not cause a large permanent compression distortion.
[0027]
Further, since the component 1 having the above-described configuration is formed by integrally molding the gasket 6 with respect to the gas diffusion layer 2 using a mold, the gasket 6 is bonded to the gas diffusion layer 2 with an adhesive. Compared with, the number of steps can be reduced. Therefore, the manufacturing of the component 1 can be facilitated, and the manufacturing cost or the component cost of the component 1 can be reduced.
[0028]
Further, in the component 1 having the above-described configuration, since the groove-shaped through portion 4 is provided in advance in the gas diffusion layer 2 disposed in the mold at the time of integral molding, the groove-shaped through portion 4 is used. By positioning the gas diffusion layer 2 with respect to the mold, the gas diffusion layer 2 can be easily and accurately positioned with respect to the mold. Therefore, also from this point, the manufacturing of the component 1 can be facilitated and the molding accuracy can be improved.
[0029]
Furthermore, the component 1 having the above-described configuration is formed by integrally molding the gas diffusion layer 2 and the gasket 6 and is not formed by integrally molding the electrolyte membrane and the gasket as in the above-described prior art. Therefore, there is no possibility of damaging the electrolyte membrane having a concern about heat resistance due to heat during molding, and the concern about this point can be solved.
[0030]
In the above embodiment, the gasket 6 is formed as a double-sided gasket that protrudes on both sides of the gas diffusion layer 2, but instead, it is formed as a single-sided gasket that protrudes only on one side of the gas diffusion layer 2. It is also possible. Various cross-sectional shapes of the gasket 6 can be considered, and the present invention does not limit the cross-sectional shape. Moreover, in the said Example, although it decided to shape | mold the gasket 6 with a metal mold | die, you may decide to shape | mold using the dispenser method, the screen printing method, etc. However, when molding the gasket 6 with a mold, there is an advantage that the cross-sectional shape of the gasket 6 can be arbitrarily set.
[0031]
【The invention's effect】
The present invention has the following effects.
[0032]
That is, in the fuel cell component of the present invention having the above-described configuration, first, a through portion penetrating the gas diffusion layer in the thickness direction is provided as a groove in the gas diffusion layer in accordance with the planar arrangement of the gasket. Since the gasket is integrally formed with the gas diffusion layer along the groove-shaped through portion, most of the gasket is disposed in the groove-shaped through portion and does not overlap the gas diffusion layer on a plane. Placed in position. Accordingly, since it is possible to suppress a large amount of fiber such as carbon fiber of the gas diffusion layer from being mixed into the rubber as the gasket material, it is possible to suppress the permanent compression strain generated in the gasket when the component is mounted and used. it can.
[0033]
In addition, since the component having the above-described configuration is formed by integrally molding the gasket with respect to the gas diffusion layer, the number of processes is reduced as compared with the case where the gasket is bonded to the gas diffusion layer with an adhesive. It can be kept low. Therefore, manufacturing of the component parts can be facilitated and the cost can be reduced.
[0034]
Furthermore, since the component having the above-described configuration is formed by integrally molding a gasket with respect to the gas diffusion layer and not by integrally molding the gasket with respect to the electrolyte membrane as in the above-described conventional technology, There is no risk of damaging the electrolyte membrane due to heat at the time of molding, and thus the concern about this point can be eliminated.
[Brief description of the drawings]
FIG. 1 is a plan view of a component for a fuel cell according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view taken along line AA in FIG. Plan view of the diffusion layer molding material [FIG. 4] is also an explanatory diagram of the manufacturing process of the same component, and is a plan view showing the completed state of the gas diffusion layer alone [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Component for fuel cell 2 Gas diffusion layer 3 Through-hole part 4 Through part 5 Communication part 6 Gasket 6a Seal lip

Claims (1)

A flat gas diffusion layer (2) having a fibrous material, and a gasket (6) made of rubber disposed endlessly on the plane of the gas diffusion layer (2);
On the plane of the gas diffusion layer (2), there are provided a through hole portion (3) serving as a flow path and a through portion (4) for mounting the gasket (6). ) Penetrates the gas diffusion layer (2) in the thickness direction and is provided in a groove shape in accordance with the planar arrangement of the gasket (6), and connects the inner part and the outer part of the groove around the circumference. A bridge-like connection (5) is provided,
The gasket (6) is formed into an endless shape along the groove-shaped through portion (4) by an injection method, a dispenser method or a screen printing method, and a part of the gasket (6) is impregnated into the gas diffusion layer (2). A component for a fuel cell.

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