KR100820567B1 - A gasket for a fuel cell and a fuel cell having the same - Google Patents

Abstract

A gasket for a fuel cell is provided to prevent a gasket from being away from the original position even under a high binding pressure, to guide a bipolar plate upon stacking of a fuel cell stack, and to improve the sealing characteristics and efficiency of a fuel cell. A gasket(720) for a fuel cell seals the circumferential portions of a reaction gas channel, a cooling water channel, a reaction gas manifold and a cooling gas manifold of bipolar plates(711,712), and is formed into a closed curve shape in which the inner end and the outer end are protruded upwardly and downwardly so as to have a different height from the central portion. The inner end is formed at the exterior of the bipolar plate.

Description

Gasket for fuel cell and fuel cell having same {A GASKET FOR A FUEL CELL AND A FUEL CELL HAVING THE SAME}

1 is a side view illustrating a state in which a gasket is installed when a conventional graphite separator is laminated.

2 is a side view illustrating a state in which a gasket is installed when the conventional metal separator is laminated.

 3 is a view illustrating a part of a gasket according to an embodiment of the present invention.

4 is a side view illustrating a gasket mounted between metal separators according to an exemplary embodiment of the present invention.

FIG. 5 is a top view showing a state in which a gasket is mounted on a metal separator plate according to an embodiment of the present invention from the reaction gas channel side.

6 is a cross-sectional view taken along the lines A-A ', B-B', and C-C 'of FIG. 5, respectively.

7 illustrates a portion of a stack of fuel cells according to one embodiment of the present invention.

The present invention relates to a fuel cell gasket and a fuel cell having the same. More particularly, the present invention relates to a gasket having a structure preventing the separation from the separation plate and a stackability of the separation plate and a fuel cell having the same.

A fuel cell is a power generation device which converts chemical energy into electrical energy generally by oxidizing and reducing hydrogen and oxygen. Hydrogen is oxidized at the anode and separated into hydrogen ions and electrons, and the hydrogen ions move through the electrolyte to the cathode. At this time, the electrons move to the anode through the circuit. At the anode, a reduction reaction occurs in which hydrogen ions, electrons, and oxygen react to form water.

The fuel cell is composed of several parts. First, MEA (membrane-electrode assembly) where electrochemical reactions occur, GDL, a porous medium that evenly distributes the reaction gas on the surface of MEA, and MEA and GDL are supported. It is a separator that collects and delivers the electricity transported and generated. Dozens or hundreds of these parts form a fuel cell stack. The power generation capacity of the fuel cell increases in proportion to the reaction area of the MEA and the stacking amount of the stack. During fuel cell power generation, hydrogen, oxygen, and coolant are continuously supplied to each side of MEA, GDL, and separator plates. Securing airtightness to prevent the reaction gas and coolant from mixing with each other is one of the most important parts of fuel cell system operation. One.

Most polymer electrolyte fuel cells adopt a method of securing a gas tight structure by installing gaskets on both sides of the separator plate. When a gasket is installed, air pressure is applied to the fuel cell stack to improve airtightness and electrical conductivity. The clamping pressure of is applied. When such a load is applied, most of the existing graphite separators are deformed in the GDL and the gasket, thereby ensuring airtightness and electrical conductivity.

1 is a side view illustrating a state in which a gasket is installed when a conventional graphite separator is laminated. The graphite separator 110 has a guide 115 for mounting the gasket 20. However, since a high clamping pressure is applied when the fuel cell stack is fastened, the gasket 120 may be deformed, and stress may be applied to the graphite separator 110. Due to the brittleness of the graphite separator 110, this concentration of stress can damage the graphite separator 110.

2 is a side view illustrating a state in which a gasket is installed when the conventional metal separator is laminated. In the case of the metal separation plate 210, the rigidity is higher than that of graphite, and the separation plate 210 is not damaged, and the metal separation plate 210 has recently been spotlighted as a material for the separation plate due to its excellent properties such as electrical conductivity and thermal conductivity. . However, in the case of the metal separation plate 210 manufactured by thin plate molding, it is difficult not only to dig a separate groove structurally, but also to form a guide that can help the installation of the gasket 220 due to the limitation of formability. As a result, when the lamination of the metal separation plate 210, the gasket 220 installed on the metal separation plate 210 may not maintain the correct position. In many cases, the gasket 220 may be easily detached by the deformation generated during the fastening. do. Therefore, when the gasket 220 is separated, the stack must be stacked again, which leads to a decrease in productivity.

An object of the present invention is to provide a gasket used for a metal separator plate.

It is also an object of the present invention to provide a gasket having a structure for preventing the separation from the metal separating plate.

It is another object of the present invention to provide a gasket which can be easily guided to stack a metal separator plate.

The present invention seals around the reaction gas channel, the cooling water channel, the reaction gas manifold and the cooling water manifold of the metal separator plate, and the inner end and the outer end are formed in a closed curve shape projecting up and down so as to have a step with the middle part, respectively. It provides a fuel cell gasket, characterized in that. Through this configuration, the inner and outer ends serve to prevent the gasket from being separated from the metal separator plate. The inner and outer ends also allow the gasket to more reliably seal the reaction gas and cooling water.

In another aspect, the present invention provides a fuel cell gasket, characterized in that the outer end is formed outside the metal separator plate. Through this configuration, the gasket may guide the metal separator plate when the metal separator plate is stacked.

In addition, the present invention provides a fuel cell gasket, characterized in that the height of the protruding inner end is higher than the height of the protruding outer end. Through this configuration, the gasket can be prevented from escaping to the metal separator plate, the gasket guides the metal separator plate, and the adhesion between the gasket and the metal separator plate can be improved.

The present invention also provides a plurality of metal separator plates comprising a first metal separator plate and a second metal separator plate having a reactant gas channel, a coolant channel, a reactant gas manifold and a coolant manifold, and a plurality of metal separator plates. Located between the membrane-electrode assembly and the first metal separator and the second metal separator plate, and seals around the reaction gas channel, the coolant channel, the reaction gas manifold and the coolant manifold, the inner and outer ends It provides a fuel cell comprising a first gasket formed in a closed curve protruding up and down to have a step with the middle portion. Through this configuration, it is possible to prevent the metal separation plate and the gasket from shifting each other when the stack is fastened.

In another aspect, the present invention further comprises a second gasket sealing the periphery of the reaction gas channel, the cooling water channel, the reaction gas manifold and the cooling water manifold on one surface of the metal separator assembly for the membrane-electrode assembly. Provide a battery.

In another aspect, the present invention provides a fuel cell further comprises a sub-gasket located between the second gasket. This configuration makes it possible to cope with the height difference between the height of the second gasket and the sum of the heights of the protruding heights of the reaction gas channels formed in the metal separator plate, the heights of the membrane-electrode assemblies, and the heights of the gas diffusion layers. The separator can be sealed.

In another aspect, the present invention provides a fuel cell, characterized in that the inner end is projected higher than the boundary of the second gasket and the metal separator plate, to prevent the second gasket from being separated. Through this configuration, the stack is stably stacked by the inner end of the second gasket, which is installed at a position where the separation plate is free of irregularities and is easily separated.

In another aspect, the present invention provides a fuel cell, characterized in that the intermediate portion is formed so as to correspond to the shape of the reaction gas channel, the cooling water channel, the reaction gas manifold and the cooling water manifold, the first gasket guides the metal separator plate. do. Through this configuration, fuel cells can be stacked more easily.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

3 is a view illustrating a part of a gasket according to an embodiment of the present invention. The gasket 320 is mounted to the metal separator 310. The reaction gas channel and the cooling water channel are protruded to one surface of the metal separation plate 310 through a press stamping process. In addition, the metal separator 310 is formed with an opening used as a reaction gas manifold and a cooling water manifold. The gasket 320 seals the reactant gas manifold, the coolant manifold, the reactant gas channel, and the coolant channel, respectively. Gasket 320 is mainly formed in a closed curve shape having a width, the inner end 321 formed on the side of the inner curve of the closed curve, the outer end 322 formed on the side of the outer curve of the closed curve and between the inner and outer ends It has an intermediate portion 323 located in.

4 is a side view illustrating a gasket mounted between metal separators according to an exemplary embodiment of the present invention. The gasket 420 is positioned between the metal separator 410 including the first metal separator 411 and the second metal separator 412. The inner end 421 and the outer end 422 of the gasket 420 protrude to both sides, and are formed thicker than the middle part 423. Since the inner end 421 and the outer end 422 are thicker than the middle portion 423, the inner end 421 and the outer end 422 are restrained by the metal separating plate 410 under high fastening pressure. It cannot be moved to the position of the intermediate portion 423 by leaving. In this case, the inner end 421 may be formed on the outside of the metal separator 410 in order to widen the width of the intermediate portion 423 and to increase the contact area between the metal separator 410 and the gasket 420. In addition, formed on the outside of the metal separating plate 410, the inner end 421 may be formed to a relatively higher height protruding. Therefore, the height at which the inner end 421 protrudes is higher than the height at which the outer end 422 protrudes, thereby increasing the ability to seal the reaction gas and the cooling water flowing through the metal separation plate 410, and disengage the gasket 420. Can be prevented more reliably.

FIG. 5 is a top view showing a state in which a gasket is mounted on a metal separator plate according to an embodiment of the present invention from the reaction gas channel side. The metal separating plate 510 has a channel protruding from one surface to the other surface, and the channel is a reaction gas channel through which a reaction gas flows. On the other side, due to the bending of the reaction gas channel, a channel formed in a relatively opposite shape is formed, which is the coolant channel 512 through which the coolant flows. The metal separator 510 includes a first gasket 520 including a gasket surrounding and sealing the coolant channel 512 and the coolant manifold 516 and a gasket sealing the respective reaction gas manifolds 514 and 518. Is attached. Also on the opposite side is a second gasket (not shown). The first gasket 520 is formed in a closed curve shape and includes an intermediate portion that is a surface attached to the metal separator 510. Since the first gasket 520 has a closed curved shape having a width, the first gasket 520 has an inner closed curve and an outer closed curve. An inner end formed on the inner closed curve side of the first gasket 520 and an outer end formed on the outer closed curve side of the first gasket 520 protrude to have a step with the middle portion. The inner end seals around the reactant gas manifolds 514 and 518 and the coolant manifold 516. The inner end is formed outside the metal separator plate, ie inside the reaction gas manifolds 514 and 518 and the coolant manifold 516. Therefore, since the inner end has less spatial constraint than the outer end, the protruding height can be formed higher.

6 is a cross-sectional view taken along the lines A-A ', B-B', and C-C 'of FIG. 5, respectively. A cross-sectional view taken along the line A-A 'is a cross-sectional view taken along a line crossing the outside of the reactive gas manifold and the metal separator of the metal separator 610. The first gasket 620 and the second gasket 630 are attached to the metal separator 610. As described above, the height at which the inner end protrudes is higher than the outer end. A side protrusion is an outer end and A 'side protrusion is an inner end.

A cross-sectional view taken along the line B-B 'is a cross-sectional view taken along a line crossing the reactive gas manifold and the coolant manifold of the metal separator 610. B is the reaction gas manifold side and B 'is the cooling water manifold side. Also, the height at which the inner end of the reactive gas manifold side protrusion and the cooling water manifold side protrusion are higher than the protrusion formed on the inner side of the metal separating plate is the outer end.

A cross-sectional view taken along line C-C 'is a cross-sectional view taken along a line crossing the cooling water channel and the outside of the metal separator 610. The C side is the inner end, and the C 'side is the outer end. Unlike around the reaction gas manifold and around the cooling water manifold, the openings are not formed in the metal separation plate 610 around the cooling water channel, and there is a risk of obstructing the flow of the cooling water, and thus it is difficult to increase the protruding height of the inner end. Therefore, the protruding heights of the inner and outer ends do not differ significantly.

7 illustrates a portion of a stack of fuel cells according to one embodiment of the present invention. The fuel cell has a sandwich structure in which a membrane-electrode assembly 750 and a gas diffusion layer 760 are interposed therebetween and metal separator plates 710 are positioned on both surfaces thereof.

In the metal plate assembly 710, the coolant flows into a space formed on a surface where the first metal plate 711 and the second metal plate 712 face each other. In addition, different kinds of reaction gases flow to opposite surfaces of the first metal separator 711 and the second metal separator 712. The metal separator plate 710 is formed with a manifold for supplying the reaction gas and the coolant to the reaction gas channel and the coolant channel formed inside the metal separator. The first gasket 720 seals the coolant channel, the coolant manifold, and the reactant gas manifold between the first metal separator 711 and the second separator 712. On the other hand, the second gasket 730 seals the reaction gas channel, the reaction gas manifold and the coolant manifold on the opposite side thereof.

 The left figure corresponds to the cross-sectional view taken along the line AA ′ of FIG. 5. The first gasket 720 is separated from the intermediate portion 722 and the metal, which is a surface in close contact with the periphery of the reaction gas manifold and the inner end 721 formed protruding from the opening of the reaction gas manifold around the reaction gas manifold. The outer end 723 is formed to protrude to correspond to the shape of the plate assembly 710. Since the reaction gas channels and the coolant channels formed in the first metal separator 711 and the second metal separator 712 are formed through a press stamping process, the metal separator assembly 710 has a stepped shape of protrusions and recesses. Has Therefore, when the outer end 723 is formed in conformity with the stepped shape of the metal separator plate 710, even if a high pressure is applied from the outside during stack fastening, the outer end 723 is restrained by the metal separator plate 710, thereby preventing the first gasket from being separated. You can prevent it.

In addition, the inner end 721 of the first gasket 720 protrudes higher than the height of contact with the second gasket 730, the first metal separator 711, and the second metal separator 712. Therefore, the second gasket 730 that is hardly constrained by the metal separator plate 710 may be constrained by using the first gasket 730 to prevent the second gasket 730 from being separated.

In addition, the shape of the inner end 721, the middle portion 722 and the outer end 723 of the first gasket 730 is formed so as to correspond to the shape of the metal separation plate assembly 710 to which the first gasket 730 is in close contact. When the first and second metal separators 711 and 712 are stacked, the first gasket 730 may also guide the first and second metal separators 711 and 712.

In addition, a sub gasket 740 is provided between the second gasket 730 and the second gasket 730. The sub-gasket 740 is sealed when the height of the second gasket 730 differs from the height of the portion where the membrane-electrode assembly 750 and the gas diffusion layer 760 are provided in the metal separator assembly 710. To compensate for the lack of reliability. In addition, when the sub-gasket 740 is formed of a material having a different elastic strain from the second gasket 730, the sub gasket 740 may be more reliably sealed against external force when the stack is fastened.

The cross sectional view on the right is a cross sectional view of the fuel cell stack corresponding to FIG. It is difficult to form the inner end to protrude around the reaction gas channel and the cooling water channel. However, since the metal separator plate 710 includes protrusions for forming the reaction gas channel and the coolant channel, the separation of the second gasket 730 may be prevented by the protrusions.

The gasket according to the present invention can prevent the gasket from being released from its original position even at a high tightening pressure.

In addition, the gasket according to the present invention may guide the metal separator plate when the stack is stacked.

In addition, the fuel cell according to the present invention increases the sealing property of the cooling water and the reaction gas, it is possible to further improve the efficiency of the fuel cell.

Claims (8)

Sealing the periphery of the reaction gas channel, the cooling water channel, the reaction gas manifold and the cooling water manifold of the metal separation plate, characterized in that the inner end and the outer end is formed in a closed curve protruding up and down to have a step with the middle portion Fuel cell gasket. The method of claim 1, An inner end is a gasket for a fuel cell, characterized in that formed on the outside of the metal separator plate. The method of claim 2, A fuel cell gasket, wherein the height at which the inner end protrudes is higher than the height at which the outer end protrudes. A plurality of metal separator assemblies comprising a first metal separator and a second metal separator having a reactant gas channel, a coolant channel, a reactant gas manifold and a coolant manifold; A membrane-electrode assembly positioned between the plurality of metal separator assemblies; And Located between the first metal plate and the second metal plate, it seals around the reaction gas channel, the cooling water channel, the reaction gas manifold and the cooling water manifold, so that the inner end and the outer end have a step with the middle part. And a first gasket formed in a closed curve protruding upward and downward. The method of claim 4, wherein And a second gasket sealing a circumference of the reaction gas channel, the cooling water channel, the reaction gas manifold, and the cooling water manifold on one surface of the metal separator assembly for the membrane-electrode assembly. The method of claim 5, wherein And a sub-gasket positioned between the second gaskets. The method of claim 5, wherein The inner end of the fuel cell, characterized in that protruding higher than the boundary of the second gasket and the metal separator plate to prevent the second gasket from being separated. The method of claim 4, wherein The shape of the intermediate portion is formed so as to correspond to the shape of the reaction gas channel, the cooling water channel, the reaction gas manifold and the cooling water manifold, the first gasket guides the metal separator plate.

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