JP2007194077A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To favorably control surface pressure between an MEA part and a gasket part in the structure integrally forming the gasket part in the outer periphery of the membrane electrode assembly. <P>SOLUTION: In a fuel cell having the MEA 15 in which an electrolyte membrane 13 is interposed between a pair of electrodes 14, a gasket part 21 is formed by integrally forming the outer periphery with resin, and a separator 16 arranged on each side of the MEA 15, the separator 16 is equipped with an assembly facing part 30 facing an assembly body 20 on the inside in the surface direction than the gasket part 21 of the MEA 15; a gasket facing part 31 facing the gasket part 21; and a connecting part 32 connecting the assembly facing part 30 and the gasket facing part 31, and absorbing deformation in the crossing direction to the surface direction of the assembly facing part 30 and the gasket facing part 31. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell having a membrane-electrode assembly in which a gasket portion is integrally formed on the outer periphery.

  In recent years, a fuel cell vehicle using a fuel cell that generates power by an electrochemical reaction between a fuel gas and an oxidizing gas as an energy source has attracted attention. In such a fuel cell, a fuel cell stack in which a required number of cells that generate electricity by an electrochemical reaction between a fuel gas and an oxidizing gas are usually used. The cell structure is composed of an electrolyte membrane and its both sides. A MEA (Membrane Electrode Assembly) having a pair of electrodes disposed on the substrate and a pair of separators sandwiching the MEA.

The cell is configured to generate power by supplying an oxidizing gas or a fuel gas to each electrode through a gas flow path formed in each separator. In this type of fuel cell, a technique for controlling the surface pressure applied to the MEA and reducing the damage to the MEA due to the surface pressure is disclosed (for example, see Patent Documents 1 to 5).
JP 2004-335453 A JP 11-329468 A JP 7-153473 A JP 2003-338295 A JP 2002-117866 A

  In recent years, a gasket part on the outer peripheral side of the MEA has been integrally formed for the purpose of improving productivity. In order to ensure sealing performance, the gasket portion needs to have a relatively high surface pressure. However, in a fuel cell in which the gasket portion is integrally molded, the high surface pressure in the gasket portion is caused by the separator in the surface direction of the gasket portion. Since it is transmitted to the joined body main body which is the inner power generation part, the surface pressure of the joined body becomes too high.

  That is, in the fuel cell having a structure in which the gasket portion is integrally formed on the outer periphery of the joined body, it is difficult to achieve both the securing of the sealing performance in the gasket portion and the management of the surface pressure in the joined body. For this reason, in the structure which integrally molded the gasket part, the structure which can respectively manage the surface pressure in a joined body main body and the gasket part of the outer peripheral side was desired.

  The present invention has been made in view of the above circumstances, and in a structure in which a gasket portion is integrally formed on the outer periphery of a membrane-electrode assembly, it is possible to satisfactorily manage surface pressure between the joined body and the gasket portion. It aims to provide a simple fuel cell.

  In order to achieve the above object, a fuel cell of the present invention comprises a membrane-electrode assembly in which an electrolyte membrane is sandwiched between a pair of electrodes, and a sealing material is integrally formed on the outer periphery thereof to form a gasket portion, and the membrane A separator disposed on both sides of the electrode assembly, wherein the separator is opposed to the assembly body on the inner side in the plane direction than the gasket portion of the membrane-electrode assembly. Displacement in a direction intersecting the surface direction of the joined body facing portion and the gasket facing portion while connecting the facing portion, the gasket facing portion facing the gasket portion, and the joined body facing portion and the gasket facing portion. And an absorbable connecting portion.

  According to this configuration, since it is possible to absorb the displacement in the direction intersecting the surface direction of the joined body facing portion and the gasket facing portion by the connecting portion of the separator, it is different between the integrally molded gasket portion and the joined body main body. The contact pressure can be applied.

  That is, in order to improve productivity, in the fuel cell having a structure in which the outer periphery of the membrane-electrode assembly is integrally molded with a resin to form a gasket portion, the surface pressure management between the joined body and the gasket portion can be performed satisfactorily. It is possible to eliminate excessive surface pressure on the joined body while ensuring good sealing performance.

  In this case, it is preferable that the separator is integrally formed of metal or carbon.

  Moreover, it is preferable that the connection part of the said separator is formed in the bellows shape by making it uneven | corrugated shape by sectional view.

  ADVANTAGE OF THE INVENTION According to this invention, in the structure where the gasket part was integrally molded by the outer periphery of the membrane-electrode assembly, the surface pressure management of a conjugate | zygote main body and a gasket part can be performed favorably.

  Next, an embodiment of a fuel cell according to the present invention will be described with reference to the drawings. FIG. 1 shows a single cell (fuel cell) that generates power by receiving supply of fuel gas and oxidant gas. This cell is used as a fuel cell stack by stacking a required number of cells in the thickness direction. Is.

  This fuel cell stack is used as an in-vehicle power generation system for fuel cell vehicles, a power generation system for all moving objects such as ships, airplanes, trains or walking robots, and also as a power generation facility for buildings (housing, buildings, etc.). It can be applied to a stationary power generation system.

  As shown in FIG. 1, a cell 11 constituting a fuel cell stack includes a thin plate-shaped MEA (membrane-electrode assembly) 15 having an electrolyte membrane 13 and a pair of electrodes 14 provided on both sides thereof. The MEA 15 is composed of a pair of thin plate-like separators 16 disposed on both sides in the thickness direction. The electrode 14 constituting the MEA 15 has a laminated structure of an electrode catalyst layer and a pair of diffusion layers formed on the opposite side of each electrode catalyst layer from the electrolyte membrane 13.

  The MEA 15 has a joined body 20 composed of the above-described electrolyte membrane 13 and a pair of electrodes 14, and the joined body 20 has a central electrolyte membrane 13 and an outer periphery of the pair of electrodes 14. The gasket body 21 protrudes over the entire circumference from the outer periphery, and a gasket portion 21 integrally formed with, for example, a resin (sealant) is provided on the entire outer periphery of the joined body 20. The gasket portion 21 is integrally formed by, for example, injection molding or lamination in which a thin material is laminated in layers.

  As shown in FIG. 2, in the separator 16, a portion facing the joined body 20 of the MEA 15 is a joined body facing portion 30, and a portion facing the gasket portion 21 of the MEA 15 is a gasket facing portion 31. And between these conjugate | zygote opposing parts 30 and the gasket opposing part 31 of the circumference | surroundings is used as the connection part 32 which connects between the opposing parts 30 and 31 over the circumferential direction.

  The connecting portion 32 is formed in a bellows shape by making it uneven in a cross-sectional view, and can be easily deformed. The connecting portion 32 is structurally composed of a joined body facing portion 30 and a gasket facing portion. It is possible to absorb the displacement of 31 in the stacking direction (direction intersecting (perpendicular to) the plane direction). The number of irregularities, the height of the irregularities, and the like are not limited to the illustrated forms, and can be appropriately changed as necessary.

  The joined body facing portion 30 is formed with a concave gas flow channel groove 41 for flowing one of the fuel gas and the oxidizing gas on the facing surface facing the joined body 20, on the opposite side. A concave cooling channel groove 42 for flowing the coolant is formed on the surface. Further, a manifold 43 for supplying and discharging the fuel gas, the oxidizing gas, and the coolant is formed in the gasket portion 21 of the MEA 15 and the gasket facing portion 31 of the separator 16 so as to penetrate in the thickness direction.

  In the cell 11 having the above structure, the laminated portion of the gasket portion 21 of the MEA 15 and the gasket facing portion 31 of the separator 16 is a gasket surface pressure region α, and the joined body 20 of the MEA 15 and the joined body facing portion 30 of the separator 16 The laminated portion is the joined body surface pressure region β.

  As shown in FIG. 3, a plurality of cells (several tens to several hundreds) are stacked in the thickness direction on the gasket facing portion 31 of the separator 16 via the annular seal member 44, and stacked. The fuel cell stack 10 is configured by being sandwiched by the joined part sandwiching end plate 51 and the gasket part sandwiching end plate 52 from both sides in the direction, and the gasket part sandwiching end plate 52 and the joined part sandwiching end plate 51 respectively. A surface pressure is applied to the gasket surface pressure region α and the joined body surface pressure region β of the cell 11.

  As described above, according to the fuel cell according to the above-described embodiment, the connecting portion 32 of the separator 16 is easily deformed as compared with other portions of the separator 16, and the laminated body facing portion 30 and the gasket facing portion 31 are stacked. Since the displacement in the direction can be absorbed, different surface pressures can be applied to the integrally formed gasket portion 21 and the joined body 20.

  That is, in the fuel cell having a structure in which the outer periphery of the MEA 15 is integrally molded with a sealing material such as a resin to form the gasket portion 21 in order to improve productivity, the surface pressure management between the joined body 20 and the gasket portion 21 is improved. It is possible to eliminate the excessive surface pressure applied to the joined body 20 while ensuring good sealing performance.

  Further, the structure can be simplified by integrally forming the separator 16 with metal or carbon.

  In addition, since the connecting portion 32 is formed in an accordion shape by forming an uneven shape in a cross-sectional view, the connecting portion 32 can easily displace the joined body 20 and the gasket portion 21 in the stacking direction. Can be absorbed well.

It is sectional drawing of the cell which comprises the fuel cell of embodiment which concerns on this invention. It is a top view of the cell which comprises the fuel cell of embodiment which concerns on this invention. It is sectional drawing of the fuel cell stack explaining the fuel cell stack which laminated | stacked the cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 13 ... Electrolyte membrane, 14 ... Electrode, 15 ... MEA (membrane-electrode assembly), 16 ... Separator, 20 ... Assembly main body, 21 ... Gasket part, 30 ... Assembly opposing part, 31 ... Gasket opposing part, 32 ... Connecting part.

Claims (3)

A membrane-electrode assembly in which an electrolyte membrane is sandwiched between a pair of electrodes and a sealing material is integrally formed on the outer periphery thereof to form a gasket portion, and separators disposed on both sides of the membrane-electrode assembly. A fuel cell comprising:
The separator includes a bonded body facing portion facing the bonded body body in the surface direction of the membrane portion of the membrane-electrode assembly, a gasket facing portion facing the gasket portion, and the bonded body facing portion and the gasket. A fuel cell comprising: a connecting portion that connects between the facing portions and can absorb a displacement in a direction intersecting a surface direction of the joined body facing portion and the gasket facing portion. The fuel cell according to claim 1,
The separator is a fuel cell integrally formed of metal or carbon. The fuel cell according to claim 1 or 2,
The connecting portion of the separator is a fuel cell that is formed in an accordion shape by forming an uneven shape in a sectional view.

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