JP4193059B2 - Fuel cell components - Google Patents

Description

  The present invention relates to a fuel cell component constituting a component of a fuel cell, and more particularly to a fuel cell component formed by integrally molding a gasket with an MEA.

  As the gas flow path gasket for each cell in the fuel cell stack, a structure in which a gasket made of an elastic body such as rubber is integrally formed on a separator is most common. In addition, a gasket lip is formed on the GDL made of a porous material forming a part of the MEA and liquid rubber is impregnated into the lip forming portion of the GDL, thereby ensuring the sealing property of the GDL alone. A technique for simplifying the cell structure by eliminating seal molding has also been developed (see Patent Document 1).

  However, in the case of the above prior art, it is necessary to perform impregnation / lip formation on the GDLs on both sides of the ion exchange membrane of the MEA. Therefore, it is necessary to form the gasket twice or to perform the molding once. Then, there is a disadvantage that a through hole must be opened in the MEA. In addition, there are concerns about leakage due to the impregnated state, and there is a disadvantage that an excessive tightening force due to the reaction force of the impregnated portion of GDL is required during MEA compression.

JP 2004-95565 A

  In view of the above points, the present invention can form a gasket in one time in a fuel cell component formed by integrally molding a gasket on an MEA, and there is no need to form a through hole in the MEA. An object of the present invention is to provide a component for a fuel cell that may have a small tightening force during MEA compression.

In order to achieve the above object, a fuel cell component according to the present invention is a fuel cell component formed by integrally molding a gasket with respect to an MEA. The MEA is disposed between a pair of separators and compressed during cell assembly. A flat gasket portion made of a rubber-impregnated portion formed by impregnating a part of rubber, which is a gasket molding material, on the outer peripheral edge of the MEA, and the rubber integrally molded on the outer peripheral side of the rubber-impregnated portion And a lip integrally formed on the flat surface of the flat gasket portion, and a recess for escaping when the lip is compressed, formed on the flat surface of the flat gasket portion and on the inner and outer circumferences of the lip. In addition, the thickness of the rubber-impregnated portion and the flat gasket portion is set to be the same as the thickness of the MEA at the time of cell assembly.

  In the fuel cell component having the above-described configuration, a rubber-impregnated portion is formed on the outer peripheral edge portion of the MEA, a flat gasket portion is formed on the outer peripheral side, and a lip and a recess are formed on the flat gasket portion. Since the structure is formed, the gasket is integrally formed on the outer periphery of the MEA, not on both sides of the MEA plane. In addition, since the thickness of the rubber-impregnated portion and the flat gasket portion is set to be the same as the thickness of the MEA at the time of cell assembly, the lip of the MEA and the gasket is compressed at the time of cell assembly. And the flat gasket part is not compressed.

  The present invention has the following effects.

  That is, in the present invention, as described above, since the gaskets are integrally formed on the outer peripheral portion of the MEA, the gasket can be molded only once, and there is no need to form a through hole in the MEA. In addition, when the cell is assembled, the MEA and gasket lip are compressed, but the rubber-impregnated part and the flat gasket part are not compressed. can do. Therefore, according to the intended purpose, in the fuel cell component formed by integrally molding the gasket on the MEA, the gasket can be molded once, and it is necessary to form a through hole in the MEA. Therefore, it is possible to provide a component for a fuel cell that requires only a small tightening force during MEA compression.

  Also, if the MEA and lip are compressed during cell assembly, a reaction force is generated by the MEA and lip, but when the MEA thickness reaches the planned compression value, the rubber-impregnated portion and the flat gasket portion begin to be compressed. Therefore, the reaction force by the rubber-impregnated portion and the flat gasket portion is added to the reaction force by the MEA and the lip, and the magnitude of the reaction force increases at a stretch. Therefore, this phenomenon can be used for the fixed dimension management at the time of cell assembly, that is, the dimension control at the time of cell assembly can be easily performed by stopping the compression at the time when the reaction force increases at a stroke.

  The present application includes the following embodiments.

(1) An impregnation part having the same thickness as that of MEA compression is formed on the entire periphery of the MEA, and a flat gasket is formed on the outer side thereof. Further, on the flat gasket, the lip and both sides of the lip are escaped during lip compression. It is assumed that it has the eggplant. Furthermore, the thickness of the MEA-impregnated portion and the flat gasket is the same as that of the MEA at the time of cell assembly.
(2) An impregnated portion having the same thickness as that at the time of MEA compression is formed on the entire circumference of the MEA around 2 mm, and a flat gasket is formed on the outside thereof. Further, a gasket having a structure in which a lip and a clearance for escaping when the lip is compressed is formed on the flat gasket on both sides of the lip. Furthermore, by making the thickness of the MEA-impregnated portion and the flat gasket portion the same as the thickness of the MEA at the time of cell assembly, it is possible to easily perform fixed-size management at the time of cell assembly.
(3) According to the configuration of (1) or (2) above, since only the lip portion is compressed during cell assembly, assembly is possible with a low tightening force, and the thickness of the impregnated portion and the rubber flat gasket portion is the same as that of the cell. Because the thickness is the same as the MEA compression thickness at the time of assembly, it is easy to manage the fixed dimensions. That is, when the MEA is compressed during cell assembly, only the lip portion is compressed without compressing the rubber-impregnated portion and the rubber flat gasket portion, so that compression with a low tightening force is possible. In addition, since the thickness of the impregnated part and the flat gasket part is the same as the thickness of the MEA during compression, the lip reaction force and the flat gasket reaction force can be used when managing the cell thickness at the time of cell assembly with a constant dimension. Due to the difference, the dimensions can be easily managed during assembly.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a cross-sectional view of a main part of a fuel cell component (also referred to as MEA integrated gasket) 1 according to an embodiment of the present invention. FIG. 1 (A) shows a state before cell assembly, FIG. ) Shows the state at the time of cell assembly (ie after cell assembly).

  As shown in the figure, a fuel cell component 1 according to this embodiment is a fuel cell component 1 in which a gasket 3 is integrally formed with an MEA (membrane electrode assembly) 2, and includes a pair of separators. The MEA 2 is disposed between 4 and 4 and is compressed when the cell is assembled. A rubber impregnated portion 5 is formed by impregnating a part of rubber as a gasket molding material on the outer peripheral edge of the MEA 2. ing. Further, a flat gasket portion 6 made of the rubber is integrally formed on the outer peripheral side of the rubber impregnated portion 5, and a lip for providing a sealing function in close contact with the separator 4 on the flat surface of the flat gasket portion 6. 7 and a recess 8 for allowing the lip 7 to escape when the lip 7 is compressed.

For example, the MEA 2 has GDLs (gas diffusion layers) disposed on both upper and lower surfaces of the ion exchange membrane via electrode layers, and the GDL is formed of a porous material such as carbon fiber. It is possible to impregnate the inside with rubber, and when the cell is assembled, it is compressed so that its thickness is reduced from d ₁ (FIG. 1 (A)) to d ₂ (FIG. 1 (B)). Is possible. The thickness d ₁ of the MEA 2 before cell assembly is, for example, about 1 mm, and the thickness d ₂ of the MEA ₂ at the time of cell assembly is, for example, about 0.6 to 0.7 mm.

In contrast to the MEA 2 whose thickness changes as a result of the compression, the rubber-impregnated portion 5 and the flat gasket portion 6 have the same thickness d ₃ as the thickness d ₂ of the MEA ₂ at the time of cell assembly from the beginning of molding. Are set (d ₃ = d ₂ ), the lip 7 is integrally formed on the upper and lower surfaces of the flat gasket portion 6 thus dimensioned, and the recesses 8 are formed on the inner and outer circumferences of the lip 7 respectively. Yes. The height h of the lip 7 is, for example, about 0.3 mm. Further, the width w ₁ of the rubber-impregnated portion 5 is, for example, about ₁ to 3 mm, and the width w ₂ of the flat gasket portion 6 (that is, the gasket 3) is, for example, about 3 mm.

  When the fuel cell component 1 having the above-described configuration is manufactured, the MEA 2 is inserted into the molding die 10 as shown in FIG. 2, and in this state, rubber as a gasket molding material is injected to mold the gasket 3. . Part of the rubber is impregnated into the outer peripheral portion of the MEA 2 to form the rubber-impregnated portion 5. As shown in the figure, the parting portion 11 of the molding die 10 has an MEA compression exhibiting a protrusion 12 for stopping impregnation in addition to a space 12 for inserting the MEA 2 and a space 13 for molding the gasket 3. It is preferable to provide the part 14.

  In the fuel cell component 1 configured as described above, the rubber-impregnated portion 5 is formed on the outer peripheral edge portion of the MEA 2 as described above, and the flat gasket portion 6 is further formed on the outer peripheral side thereof. Since the lip 7 and the recess 8 are formed on the top, as shown in FIG. 1A, the gasket 3 is integrally formed on the outer peripheral portion of the MEA 2 instead of on both sides of the MEA 2 in the plane. Therefore, the gasket 3 can be molded once by using the mold 10 as shown, and there is no need to form a material communication portion such as a through hole in the MEA 2.

Further, since the thickness d _{3 of} the rubber-impregnated portion 5 and the flat gasket portion 6 is set to be the same as the thickness d ₂ of the MEA ₂ at the time of cell assembly, as shown in FIG. At the time of cell assembly, the MEA 2 and the lip 7 of the gasket 3 are compressed, but the rubber-impregnated portion 5 and the flat gasket portion 6 are not compressed. Therefore, compared with the case where all these are compressed simultaneously, the fastening force at the time of MEA2 compression can be made small.

  Therefore, according to the intended purpose, in the fuel cell component 1 formed by integrally molding the gasket 3 with respect to the MEA 2, the gasket 3 can be molded once, and a through-hole or the like can be formed on the MEA 2. It is possible to provide the fuel cell component 1 that does not need to be formed and that requires a small tightening force when the MEA 2 is compressed.

  Further, as detailed above, the dimensional management at the time of cell assembly can be easily performed using the phenomenon that the reaction force at the time of compression increases at a stretch.

BRIEF DESCRIPTION OF THE DRAWINGS It is principal part sectional drawing of the component for fuel cells which concerns on the Example of this invention, Comprising: The figure (A) is principal part sectional drawing which shows the state before cell assembly, The figure (B) is the state at the time of cell assembly. Sectional view showing the main parts Explanatory drawing which shows the manufacturing method of the components for the fuel cell

Explanation of symbols

1 Fuel cell components 2 MEA
3 Gasket 4 Separator 5 Rubber impregnated part 6 Flat gasket part 7 Lip 8 Recessed part 10 Mold 11 Parting part 12, 13 Space 14 MEA compression part

Claims (1)

In the fuel cell component (1) formed by integrally molding the gasket (3) with respect to the MEA (2),
The MEA (2) disposed between a pair of separators (4) and compressed during cell assembly, and the outer peripheral edge of the MEA (2) is impregnated with a part of rubber as a gasket molding material. The rubber-impregnated portion (5), the flat gasket portion (6) made of the rubber integrally formed on the outer peripheral side of the rubber-impregnated portion (5), and the flat portion of the flat gasket portion (6) are integrally formed. A lip (7), and a recess (8) for escaping when the lip (7) is formed on the inner and outer periphery of the lip (7) on the flat gasket portion (6). Have
The fuel cell characterized in that the thickness (d ₃ ) of the rubber-impregnated portion (5) and the flat gasket portion (6) is set to be the same as the thickness (d ₂ ) of the MEA (2) at the time of cell assembly. Components.

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