KR102492886B1 - Method of fabricating gasket for fuel cell - Google Patents

Abstract

A method for manufacturing a gasket for a fuel cell according to the present invention includes extruding and molding a gasket material using a roll die forming process to make a gasket material sheet, and injecting the gasket material sheet into a progressive forming process to form a plurality of manifold holes. and forming concavo-convex portions around the gasket raw material sheet.

Description

Gasket manufacturing method for fuel cell {METHOD OF FABRICATING GASKET FOR FUEL CELL}

The present invention relates to a method for manufacturing a gasket for a fuel cell, and more particularly, to a method for manufacturing a gasket for a fuel cell capable of improving productivity by reducing production time.

Recently, a polymer electrolyte membrane fuel cell (PEMFC) has been widely used as a fuel cell for automobiles. A polymer electrolyte membrane fuel cell is used in the form of a stack in which a plurality of unit cells are stacked and assembled.

A unit cell is composed of a membrane-electrode assembly (MEA) and a separator. A gas diffusion layer (GDL) may be further provided between the membrane electrode assembly and the separator to help diffusion of hydrogen and oxygen. The membrane electrode assembly consists of a polymer electrolyte membrane that moves hydrogen ions, a catalyst electrode composed of a platinum catalyst applied to both sides of the electrolyte membrane, and an anode (hydrogen electrode) and a reduction electrode (cathode). It consists of

Looking at the reaction of the fuel cell, after the hydrogen supplied to the anode, which is the oxidation electrode on one side of the membrane-electrode assembly, is separated into protons and electrons, the hydrogen ions pass through the electrolyte membrane to the reduction electrode, It moves towards the cathode and the electrons move to the cathode through the external conductor. At the cathode, when oxygen molecules, hydrogen ions and electrons react together, they produce electricity and heat, as well as water as a reaction by-product.

In order to efficiently perform the reaction of hydrogen and oxygen in a fuel cell, it is necessary to suppress the infiltration of coolant or the leakage of reaction gas through a fine gap between the membrane electrode assembly and the separator. If the coolant permeates or the reaction gas leaks to the outside, the normal reaction between hydrogen and oxygen may be hindered, thereby deteriorating the performance of the fuel cell. In order to prevent this, a gasket is closely coupled between the membrane electrode assembly of the fuel cell and the separator or between the GDL and the separator to perform a sealing function.

Recently, as interest in environment-friendliness increases and hydrogen vehicles begin to be commercially sold, interest in hydrogen vehicles is also increasing. Accordingly, competition for R&D on fuel cells, the core of hydrogen vehicles, is getting fiercer. As the sales volume of hydrogen vehicles increases, the need for mass production of gaskets and parts of fuel cell stacks is emerging.

Conventionally, an injection molding method or a dispenser method has been mainly used for gasket production. The injection molding method is a method of producing gaskets through a process of mixing various raw materials and auxiliary materials, injecting them at high pressure, injecting them into the cavity of an injection mold, and heating and curing them for a certain period of time. And, the dispenser method is a method of producing a gasket by mixing and melting various raw materials and auxiliary materials and impregnating the molten mixed material into gaps formed in the separation plate.

The injection molding method consumes about 60 seconds to produce one gasket, and the dispenser method consumes about 120 seconds to produce one gasket. That is, the injection molding method and the dispenser method are not suitable for mass-producing gaskets, and a manufacturing method capable of efficiently mass-producing gaskets is required.

A technical problem to be achieved by the present invention is to provide a method for manufacturing a gasket for a fuel cell capable of reducing production time and increasing productivity.

In order to achieve the above technical problem, a method for manufacturing a gasket for a fuel cell according to an embodiment of the present invention includes extruding and molding a gasket raw material using a roll die forming process to make a gasket raw material sheet, and the gasket raw material sheet. to a progressive molding process to form a plurality of manifold holes, and forming concavo-convex portions around the gasket raw material sheet.

In addition, in order to achieve the above technical problem, a method for manufacturing a gasket for a fuel cell according to an embodiment of the present invention includes a first step of extruding the input gasket material in a molten state, and molding the extruded gasket material into a sheet form A second step of forming a gasket raw material sheet, a third step of forming an initial gasket by cutting the gasket raw material sheet, and forming a plurality of manifold holes through the gasket, A fourth step of forming concavo-convex portions along the periphery of the manifold hole.

According to an embodiment of the present invention, the roll die forming process and the progressive forming process are connected so that the entire process from inputting gasket raw materials to gasket completion is automatically and sequentially performed, thereby reducing gasket production time and increasing productivity.

According to an embodiment of the present invention, a roll die forming process is applied to the process of making a gasket raw material sheet from a gasket raw material sheet, and a progressive forming process is applied to the process of making a gasket from a gasket raw material sheet to modularize the entire process, thereby proceeding with gasket production. Depending on the condition, each module process can be individually controlled to increase productivity.

The effects of the present invention are not limited to the above effects, and should be understood to include all effects that can be inferred from the detailed description of the present invention or the configuration of the invention described in the claims.

1 is a view schematically showing a forming method using a roll die applied to a method for manufacturing a gasket for a fuel cell according to an embodiment of the present invention.
2 is a diagram schematically illustrating a molding method using a progressive mold applied to a method for manufacturing a gasket for a fuel cell according to an embodiment of the present invention.
3 is a view sequentially showing a process in which a gasket raw material sheet is formed into a gasket through the progressive forming process of the present invention.
FIG. 4 is a cross-sectional view showing a section II′ of FIG. 3 .
5 is a flowchart sequentially illustrating a method of manufacturing a gasket for a fuel cell according to an embodiment of the present invention.

Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and, therefore, is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part is said to be "connected (connected, contacted, combined)" with another part, this is not only "directly connected", but also "indirectly connected" with another member in between. "Including cases where In addition, when a part "includes" a certain component, it means that it may further include other components without excluding other components unless otherwise stated.

Terms used in this specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "include" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Hereinafter, a method for manufacturing a gasket for a fuel cell according to the present invention will be described in detail with reference to the drawings.

According to an embodiment of the present invention, a gasket raw material sheet is collectively manufactured through a roll die forming process, and a gasket raw material sheet is sequentially processed through a progressive forming process to manufacture a gasket for a fuel cell. . It is characterized in that the roll die forming process and the progressive forming process are continuously performed as one complex process.

1 is a view schematically showing a forming method using a roll die applied to a method for manufacturing a gasket for a fuel cell according to an embodiment of the present invention.

The roll die forming system includes a hopper 12 into which the raw material 20 is input, an extruder 10 that compresses and injects the raw material 20, and pushes the extruded molten raw material according to the shape of a straight die hole. A T-die 11, a plurality of rolls 13, 14, and 15 for processing the raw material in a molten state into a sheet form, a thickness meter 16 for adjusting the thickness of the sheet to be processed, and a trimmer 17 , trimmer).

Looking at the process of roll die forming using the roll die forming system configured as described above is as follows.

The raw material 20 put into the hopper 12 is dehumidified by high-temperature hot air, and the raw material 20 is extruded at high temperature and high pressure by the extruder 10 and injected through the T-die 11 in a molten state. do.

An elastomer may be used as a raw material used in manufacturing the gasket. Elastomers include TPE (Thermoplastic Elastomer) and TPV (Thermoplastic Vulcanizates). TPE is an eco-friendly material that has both the elasticity of rubber and the thermoplasticity of plastic. It has excellent physical properties such as resilience and shock absorption, processability, and light weight, and is widely used in automobiles, construction, medical care, and sports. Depending on the combination of rubber and plastic, TPE becomes rubber-like thermoplastic vulcanizates (TPV) and plastic-like TPEE and TPU. Among them, TPV, which has excellent elasticity and has a better sealing effect, would be more suitable as a gasket material.

In the embodiment of the present invention, an elastomer is suggested as a gasket raw material, but it is not limited thereto, and various raw materials such as silicon, fluorine, olefin, Ethylene Propylene Diene Trepolymer, and Teflon sheet may be used.

The raw material 20 injected into the hopper 12 is preferably a granular elastomer. By making the thermoplastic material in the form of granules and introducing it, not only the introduction into the hopper 12 is smooth, but also the extrusion process can be performed more smoothly at high temperature and high pressure.

Meanwhile, the elastomer injected in a molten state through the T-die 11 is cooled while passing through the compression roll 13, the first cooling roll 14, and the second cooling roll 15 to form a sheet. processed

Since the elastomer is formed into a gasket raw material sheet through the roll die forming process, it must be processed into a thin thickness. Therefore, by measuring the thickness of the sheet in real time with the thickness meter 16 during the roll die forming process, the processing thickness of the sheet can be adjusted by adjusting the distance between the rolls. The thickness of the raw material sheet for gasket production is preferably 3T (3 mm), but is not limited to this value, and may be manufactured in the range of 1 to 4 T (1 to 4 mm).

In this way, the granular elastomer injected into the hopper 12 is formed into a sheet having a thickness suitable for manufacturing gaskets through a plurality of rolls, and finally cut by the trimmer 17 to have an appropriate width to form a gasket raw material sheet ( 30) is taken out.

The gasket raw material sheet 30 may be directly put into a progressive molding process and molded into a gasket.

2 is a diagram schematically illustrating a molding method using a progressive mold applied to a method for manufacturing a gasket for a fuel cell according to an embodiment of the present invention.

Progressive molding is a press processing method in which materials are sequentially transported to a number of processing units to make products with complex shapes, and continuous operation is performed, which can improve processing efficiency and productivity.

There are many processes such as piercing, bending, forming, drawing, and blanking in the progressive forming process, but only some processes are shown in FIG. 2 .

As shown, in the progressive press, a piercing punch 42, dies 44 and 46, and a trimming die 48 are attached to the upper die holder 40, and 1 to the lower die holder 50. A secondary drawing punch 52, a blank holder 54, a redrawing punch 56, and a trimming punch 58 are attached.

Looking at the process of progressive molding using the progressive press configured as described above is as follows.

The piercing punch 42 may form a hole by penetrating the inserted gasket raw material sheet 30 . In the piercing process, the remaining part except for the part penetrated by the punch becomes a product. On the other hand, in the blanking process that penetrates a part of the sheet, similar to the piercing process, the through hole becomes a product.

The primary drawing punch 52 forms concavo-convex shapes on the gasket raw material sheet 30 together with the die 44. Then, the re-drawing punch 56 and the die 46 readjust the concavo-convex shape. In FIG. 2, a drawing punch is used to form irregularities on the sheet, but a forming punch may also be used.

The trimming punch 58 cuts a part of the gasket raw material sheet 30 together with the trimming die 48 . At this time, the trimming punch 58 or the trimming die 48 has an inclined cutting surface.

Although only a few processes used in the progressive forming process are presented in FIG. 2 , other processes such as forming and blanking processes may be further included depending on the gasket forming method, and the order of the presented processes may be changed.

3 is a view sequentially showing a process in which a gasket raw material sheet is formed into a gasket through the progressive forming process of the present invention.

First, referring to (a), the gasket raw material sheet 130 made through roll die forming is put into a progressive forming process.

Next, as in (b), the gasket 131 of the initial shape is formed by cutting the edge region of the gasket raw material sheet 130 . In this case, the edge region may be removed using a blanking process instead of cutting.

Next, referring to (c), a plurality of manifold holes 133a, 133b, 134a, 134b, 135a, and 135b are formed in the gasket 131 through a piercing process. Here, the first manifold hole 133a corresponds to the manifold hole through which hydrogen gas is injected in the fuel cell stack and performs a sealing function, and the second manifold hole 133b corresponds to the manifold hole through which hydrogen gas is discharged. Corresponds to perform sealing function. In addition, the third manifold hole 134a corresponds to the manifold hole through which air is introduced in the fuel cell stack and performs a sealing function, and the fourth manifold hole 134b corresponds to the manifold hole through which air is discharged. perform a sealing function. In addition, the fifth manifold hole 135a performs a sealing function corresponding to the manifold hole through which the coolant is injected in the fuel cell stack, and the sixth manifold hole 135b corresponds to the manifold hole through which the coolant is discharged. perform a sealing function. Meanwhile, the seventh manifold hole 132 performs a sealing function corresponding to the position of the membrane electrode assembly in the fuel cell stack.

Referring to (d), the first thin film thickness portion around the circumference 136 of the first to sixth manifold holes 133a, 133b, 134a, 134b, 135a, and 135b is processed. At this time, the circumferences 136 of the first to sixth manifold holes 133a, 133b, 134a, 134b, 135a, 135b are bent in one direction through a bending process, etc., so that gaskets and fuel cell separators or GDL It is possible to increase the adhesion effect with the back.

Looking at (e), the secondary thin film thickness around the circumference 137 of the seventh manifold hole 1312 is processed. At this time, the circumference 137 of the seventh manifold hole 132 may be processed to be bent in one direction through a bending process or the like to increase the adhesion effect between the gasket and the membrane electrode assembly.

Next, looking at (f), concavo-convex portions are formed along the circumference of the gasket 131. Further, concavo-convex portions are formed along a part or all of the periphery of each manifold hole. At this time, a drawing process may be used, and a redrawing process may be added to more precisely process or readjust the concavo-convex shape. Alternatively, the concavo-convex shape may be formed by performing a forming process instead of a drawing process.

The process of forming the plurality of manifold holes 133a, 133b, 134a, 134b, 135a, and 135b in (c) and the process of forming concavo-convex portions along the circumference of the gasket 131 in (f) are ordered according to the manufacturing environment. may change. That is, the manifold holes 133a , 133b , 134a , 134b , 135a , and 135b may be processed after first forming the concave-convex portion on the gasket 131 .

On the other hand, since each side of the gasket completed through various process steps may have an irregular shape without being smooth, the gasket may be molded smoothly by uniformly cutting the sides of the gasket through a trimming process.

FIG. 4 is a cross-sectional view illustrating a line II' of FIG. 3 .

As shown, a concave-convex portion 238 is formed on a portion of the gasket 231 . The concavo-convex portion 238 may be formed by a drawing process or a forming process among progressive forming processes.

As described above, the uneven portion 238 formed along the circumference of the gasket 231 and some or all of the manifold holes 132 , 133a , 133b , 134a , 134b , 135a , and 135b is in close contact with other membranes of the fuel cell stack. It is a structure to increase the sealing effect in bonding.

5 is a flowchart sequentially illustrating a method of manufacturing a gasket for a fuel cell according to an embodiment of the present invention.

As shown, in step S312, a gasket raw material is introduced into the roll die device. It is preferable to use granular elastomers as gasket raw materials, but silicone-based, fluorine-based, olefin-based, Ethylene Propylene Diene Trepolymer rubber, Teflon sheets, and the like may also be used.

The input gasket raw material is extruded through a T-die and formed into a sheet form while passing through a plurality of rolls. At this time, in step S314, the thickness of the gasket raw material sheet is adjusted so as to be suitable for manufacturing a gasket in the form of a thin film. It is suitable to be processed to a thickness of 1 to 4 mm.

Next, in step S316, the non-uniform sides of the sheet are trimmed to complete the gasket raw material sheet.

The above steps (S312 to 316) are steps to which the roll die forming process (S310) is applied.

Next, in step S322, the gasket raw material sheet completed in the roll die forming step S310 is put into the progressive forming step S320.

The completed gasket raw material sheet is automatically put into the progressive molding process (S320). In the present invention, the roll die forming process (S310) and the progressive forming process (320) are connected so that the process proceeds sequentially.

Next, in step S324, the gasket raw material sheet is cut to form an initial gasket. When cutting the gasket material sheet, a cutting process or a blanking process for removing an outer region may be used.

Next, in step 326, a plurality of manifold holes are formed through the gasket. At this time, a piercing process may be used.

Next, in step 328, first and second thin film thickness processing of the edge of the manifold hole is performed.

Next, in operation 330, concavo-convex portions are formed along the circumference of the gasket to obtain a sealing effect by increasing adhesion of the fuel cell stack to other structures. In addition, the concavo-convex portion may be formed along a part or all of the circumference of the manifold hole. At this time, a drawing process or a forming process may be used to form the concave-convex portion.

Either one of the process of forming a plurality of manifold holes in step S326 and the process of forming uneven portions on the gasket in step 330 may be performed first depending on the manufacturing environment. That is, the manifold hole may be formed after first forming the concave-convex portion on the gasket.

Meanwhile, a re-drawing process may be added to more precisely process the concavo-convex part or to readjust the shape.

In the next step (S332), the completed gasket is taken out.

As such, it takes 10 to 20 seconds to complete one gasket through the gasket manufacturing method in which the roll die forming process (S310) and the progressive forming process (S320) are continuously performed. Accordingly, the gasket production time is greatly reduced compared to the gasket production time using the conventional injection molding process or the dispenser process.

As described above, the method for manufacturing a gasket for a fuel cell according to an embodiment of the present invention connects a roll die forming process and a progressive forming process so that a plurality of processes are sequentially and automatically performed from inputting gasket raw materials to gasket completion, thereby reducing production time. reduce and increase productivity.

In addition, the method for manufacturing a gasket for a fuel cell according to an embodiment of the present invention modularizes the entire gasket manufacturing process into two parts. That is, the gasket raw material is processed into a gasket raw material sheet through a roll die forming process, and the gasket raw material sheet is processed into a gasket through a progressive forming process.

In this way, by modularizing the entire process, part or all of the process can be controlled according to the gasket manufacturing progress. For example, if a large number of gasket material sheets have already been produced, the roll die forming process may be stopped or the process speed may be reduced and the progressive forming process may be intensively performed. That is, it is possible to increase productivity by individually controlling the module process according to the gasket production progress.

10: extruder
20: raw material
30: gasket raw material sheet
40: die holder
50: punch holder
130: gasket raw material sheet
131, 231: gasket

Claims (10)

Making a gasket raw material sheet by extruding and molding the gasket raw material using a roll die forming process;
The method of manufacturing a gasket for a fuel cell comprising the steps of introducing the gasket raw material sheet into a progressive forming process to form a plurality of manifold holes and forming concavo-convex portions around the gasket raw material sheet.
A first step of extruding the input gasket material in a molten state;
A second step of molding the extruded gasket raw material into a sheet form to form a gasket raw material sheet;
A third step of cutting the gasket raw material sheet to form a gasket of an initial shape;
and a fourth step of forming a plurality of manifold holes through the gasket and forming concave-convex portions along the circumference of the gasket and the manifold hole.
According to claim 1 or 2,
The gasket manufacturing method for a fuel cell, wherein the gasket raw material is an elastomer.
According to claim 1 or 2,
The gasket raw material is a method for manufacturing a gasket for a fuel cell in the form of granules.
According to claim 1,
The method of manufacturing a gasket for a fuel cell, wherein the manufacturing of the gasket raw material sheet includes adjusting and trimming the thickness of the gasket raw material sheet.
According to claim 1,
The gasket manufacturing method for a fuel cell, wherein the gasket raw material sheet is automatically introduced into the progressive molding process.
According to claim 2,
A method for manufacturing a gasket for a fuel cell, wherein a roll die molding process is used in the first and second steps, and a progressive molding process is used in the third and fourth steps.
According to claim 2,
The second step includes adjusting and trimming the thickness of the gasket raw material sheet.
According to claim 2,
A gasket manufacturing method for a fuel cell, wherein the gasket raw material sheet formed in the second step is automatically introduced into the third step.
According to claim 2,
The method of manufacturing a gasket for a fuel cell, wherein any one of the process of forming the plurality of manifold holes and the process of forming the concavo-convex portion is performed first.

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