Heating-pressurizing zig for manufacturing 5-layer MEA

Abstract

The present invention provides a heating-pressurizing jig for manufacturing a 5-layer membrane electrode assembly (MEA), in which: metal plates are formed integrally with heating plates to obviate the difficulty in increasing the temperature of the metal plates to a normal state every time when manufacturing a plurality of 5-layer MEAs; an MEA is mounted to external guides while being spaced apart from lower guides at predetermined intervals to prevent the MEA from being dried, contracted and deformed by the heated metal plates; and the lower guides and upper plate supports are elastically supported by springs, respectively, so that the external guides can respond in real time to the change in the thickness caused when upper and lower gas diffusion layers are compressed, thus preventing the MEA from being bent.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims under 35 U.S.C. §119(a) on Korean Patent Application No. 10-2007-0098651, filed on Oct. 1, 2007, the entire contents of which are incorporated herein by reference.

BACKGROUND

(a) Technical Field

The present invention relates to a heating-pressurizing jig for manufacturing a 5-layer membrane electrode assembly (MEA). More particularly, the present invention relates to a heating-pressurizing jig for manufacturing a 5-layer MEA, in which external guides are provided to separate an MEA from heating plates, metal plates are integrally connected to the heating plates to preserve the temperature of the metal plates for a predetermined period of time, and a spring structure is provided to actively adjust the position of the external guides according to the thickness of a gas diffusion layer.

(b) Background Art

A fuel cell includes an MEA consisting of electrode catalysts in which fuel gasses such as hydrogen and air react and an electrolyte membrane for transporting hydrogen ions in a fuel cell.

The fuel cell also includes a gas diffusion layer (GDL) to uniformly diffuse the gas supplied through a separator flow field and effectively discharge water generated as a result of an electrochemical reaction.

The MEA, GDL and separator are sequentially stacked to constitute a fuel cell stack. In this case, if the MEA and GDL are modularized, the productivity of the fuel cell stack can be increased.

A 5-layer MEA and a method for manufacturing the same will be described with reference to accompanying drawings below.

FIG. 1 is a schematic diagram of a 5-layer MEA, and FIGS. 2A and 2B are diagrams illustrating positional relationship between a gas diffusion layer and electrode catalysts of the 5-layer MEA of FIG. 1.

Usually, an MEA 130 composed of a hydrogen electrode catalyst 110, a solid electrolyte membrane 100 and an air electrode catalyst 120 is called a 3-layer. A GDL 140 is attached to both sides of the MEA 130. For convenience of manufacturing, one MEA 130 and two GDLs 140 are bonded to manufacture a final product, which is called a 5-layer MEA 90.

In order to manufacture the 5-layer MEA 90, the components are sequentially stacked, aligned and then bonded by applying pressure at a predetermined temperature for a predetermined period of time.

The temperature and pressure vary according to product characteristics and various kinds of additives are added thereto for the purpose of bonding the components, if necessary.

In manufacturing the 5-layer MEA 90, a hot press the temperature and pressure of which are adjustable and a jig that can place the components at an accurate position are needed.

Normally, the GDL 140, the MEA 130 and the GDL 140 are sequentially stacked and a uniform pressure is applied to both the GDLs 140 using heated hot plates.

Here, as shown in FIG. 2A, one of the important things to be considered in manufacturing the 5-layer MEA 90 is that both GDLs 140 should completely cover the electrode catalysts 110 and 120 of the MEA 130 and the positions of both the GDLs 140 should accurately coincide with each other.

As shown in FIG. 2B, if the GDL 140 does not completely cover the electrode catalysts 110 and 120, gas cannot be sufficiently supplied to the catalysts, thus degrading the performance of the fuel cell. Moreover, if the GDL 140 comes out of the separator, it is impossible to manufacture the fuel cell.

Furthermore, if the positions of both the GDLs 140 do not coincide with each other, a force imbalance is created in manufacturing the fuel cell, thus degrading the performance of the fuel cell.

In connection with such a heating-pressurizing jig, Japanese Patent Application Publication No. 2000-208140 discloses a lamination device including heating type compression main bodies arranged in parallel, between which electrode members are inserted to be heated and compressed.

Moreover, U.S. Pat. No. 6,613,470 discloses a jig that pre-heats and pre-pressurizes components to be temporarily fixed before manufacturing an MEA by an overall heating-pressurizing process.

The conventional heating-pressurizing jig for manufacturing a 5-layer MEA will be described in detail below with reference to FIG. 3.

FIG. 3 is a schematic diagram of the conventional heating-pressurizing jig for manufacturing a 5-layer MEA. As shown in the figure, a lower metal plate 160 is disposed between main bodies 150, a lower GDL 170 is placed on the top of the lower metal plate 160, and an MEA 130 is stacked on the top of the lower GDL 170.

A GDL guide 190 is mounted on both sides of the MEA 130, an upper GDL 200 is placed thereon, and an upper metal plate is covered thereon. Then, predetermined temperature and pressure are applied using a hot press, not depicted, thereto to form a 5-layer MEA.

In this case, since hot plates, not depicted, of the hot press are spaced away from the upper and lower metal plates 160 and 210, it is difficult to maintain the temperature and it takes a lot of time to increase the temperature of the upper and lower metal plates 160 and 210 to a desired level.

Moreover, since the polymer MEA 130 is placed on the heated lower metal plate 160, the MEA 130 may be wrinkled due to moisture evaporation, thus degrading the bonding strength, MEA properties, and dimensional stability.

In addition, during the pressurizing process by the jig, both sides of the MEA 130 coming in contact with the ends of the upper and lower GDLs 200 and 170 may be bent while the upper and lower GDLs 200 and 170 are compressed, thus being damaged.

The information disclosed in this Background section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art.

SUMMARY OF THE DISCLOSURE

Accordingly, the present invention has been made in an effort to solve the above-described drawbacks, and one of the objects of the present invention is to provide a heating-pressurizing jig for manufacturing a 5-layer MEA with an improved structure to effectively manufacture the 5-layer MEA.

In one aspect, the present invention provides a heating-pressurizing jig for manufacturing a 5-layer membrane electrode assembly, the jig comprising: a lower metal plate, a lower guide, a guide spring, an external guide, an upper metal plate, and an upper plate support. The lower metal plate is installed on the top surface of a lower heating plate. On the lower metal plate, a lower gas diffusion layer is stacked. The lower guide is installed on both sides of the lower metal plate to guide the lower gas diffusion layer to a predetermined position accurately. The guide spring is installed below the lower guide to elastically support the lower guide. The external guide is mounted on the top of the lower guide to fix a membrane electrode assembly and an upper gas diffusion layer. The upper metal plate is mounted on the bottom surface of an upper heating plate. The upper metal plate pressurizes the upper gas diffusion layer when a press is moved down. The upper plate support is installed on both sides of the upper metal plate. The upper plate support comes in contact with the external guide when the press is moved down.

In a preferred embodiment, the upper plate support is elastically supported by an upper plate spring.

In another preferred embodiment, an insulating material is disposed between the guide spring and the lower heating plate.

In still another preferred embodiment, a projection is formed on the bottom of the external guide and an insertion groove corresponding to the projection is formed on the top of the lower guide.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a 5-layer MEA;

FIGS. 2A and 2B are diagrams illustrating positional relationship between a gas diffusion layer and electrode catalysts of the 5-layer MEA of FIG. 1;

FIG. 3 is a schematic diagram of a conventional heating-pressurizing jig for manufacturing a 5-layer MEA;

FIG. 4 is a schematic diagram of a heating-pressurizing jig for manufacturing a 5-layer MEA in accordance with a preferred embodiment of the present invention; and

FIG. 5 is an operational diagram of the heating-pressurizing jig for manufacturing a 5-layer MEA in accordance with a preferred embodiment of the present invention.

Reference numerals set forth in the Drawings includes reference to the following elements as further discussed below:

130: MEA               200: GDL
210: lower metal plate 220: guide spring
230: lower guide       260: insulating material
270: external guide    300: upper metal plate

DETAILED DESCRIPTION

Reference will now be made in detail to the preferred embodiment of the present invention, examples of which are illustrated in the drawings attached hereinafter, wherein like reference numerals refer to like elements throughout. The embodiments are described below so as to explain the present invention by referring to the figures.

FIG. 4 is a schematic diagram of a heating-pressurizing jig for manufacturing a 5-layer MEA in accordance with a preferred embodiment of the present invention.

As shown in the figure, a lower guide 230 supported by a guide spring 220 is installed on both sides of a lower metal plate 210 on which a lower gas diffusion layer (GDL) 170 is stacked. An external guide 270 for fixing a membrane electrode assembly (MEA) 130 and an upper GDL 200 is provided on the top of the lower guide 230. Moreover, an upper plate support 310 and an upper metal plate 300 which pressurize the external guide 270 and the upper GDL 200, respectively, when a press 360 is moved down are provided on the top of the external guide 270.

The lower metal plate 210 is formed integrally with the top of a lower heating plate 250 to transfer heat generated from the lower heating plate 250 to the lower GDL 170 stacked on the top of the lower metal plate 210.

The lower guide 230 is mounted closely to both sides of the lower metal plate 210 to guide the lower GDL 170 so as to be accurately positioned when the lower GDL 170 is stacked on the top surface of the lower metal plate 210.

In this case, the distance between both the lower guides 230 is equal to the length of the lower GDL 170 and the height of the lower guides 230 is greater than that of the lower metal plate 210 such that the lower GDL 170 is disposed between both the lower guides 230.

Moreover, the guide spring 220 is mounted below the lower guide 230 such that the lower guide 230 contracts when the upper metal plate 300 and the upper plate support 310 are pressurized. A guide support 240 is provided next to the lower guide 230 so that the lower guide 230 is not pushed to the outside when the lower guide 230 contracts.

Here, an insulating material 260 is stacked on the bottom of the guide spring 220 and the guide support 240 so that the heat of the lower heating plate 250 is not directly transferred to the guide spring 220 and the guide support 240.

The external guide 270 is mounted on the top of both the lower guides 230 and includes an insertion portion 271 for guiding the MEA 130 and a guide portion 272 mounted on the top surface of the insertion portion 271 to guide the upper GDL 200.

In this case, the distance between the insertion portions 271 is equal to the length of the MEA 130 and the distance between the guide portions 272 is equal to the length of the upper and lower GDLs 200 and 170.

Moreover, a projection 280 is formed on the bottom of the external guide 270 and an insertion groove 290 corresponding to the projection 280 is formed on the top of the lower guide 230 so that the external guide 270 is mounted at an accurate position of the lower guide 230, and thereby the lower GDL 170 can completely cover the electrode catalyst of the MEA 130.

Like this, the MEA 130 and the upper GDL 200 are separately mounted to the external guides 270 so that they are spaced apart from the lower metal plate 210 before the operation of the press 360, thus preventing the MEA 130 from being dried and deformed by the heated lower metal plate 210.

The upper metal plate 300 is mounted in the center of the bottom of an upper heating plate 340 and moved down during the operation of the press 360, thus pressurizing the MEA 130, mounted to the external guides 270, and the lower GDL 170.

Here, the sizes of the upper and lower metal plates 300 and 210 are the same as those of the upper and lower GDLs 200 and 170 so that the pressure of the upper and lower metal plates 300 and 210 is uniformed applied to the overall surface of the upper and lower GDLs 200 and 170.

Moreover, a fixing body 330 having an internal space 350 is mounted on both sides of the upper metal plate 300 and a portion of the upper plate support 310 is inserted and mounted in the internal space 350 of the fixing body 330 such that the upper plate support 310 can move up and down.

Here, an upper plate spring 320 is disposed between the upper plate support 310 and the fixing body 330 to elastically support the upper plate support 310 when the upper plate support 310 pressurizes the external guide 270.

Next, the operation of the heating-pressurizing jig for manufacturing a 5-layer MEA having the above configuration will be described with reference to FIG. 5.

FIG. 5 is an operational diagram of the heating-pressurizing jig for manufacturing a 5-layer MEA in accordance with a preferred embodiment of the present invention.

First, the lower GDL 170 is mounted on the top surface of the lower metal plate 210 and the external guides 270 on which the MEA 130 and the upper GDL 200 are stacked are installed to coincide with the insertion grooves 290 of the lower guides 230.

Subsequently, as shown in FIG. 5, the upper heating plate 340 is moved down by the operation of the press 360 according to the pressure of a load cell 370 installed on the top of the press 360, and thus the upper plate supports 310 mounted on the bottom of the upper heating plate 340 pressurize the external guides 270.

Next, as the upper heating plate 340 is further moved down, the guide springs 220 elastically supporting the lower guides 230 are contracted such that the MEA 130 comes in contact with the lower GDL 170. Then, as the upper plate springs 320 elastically supporting the upper plate supports 310 are contracted, the upper metal plate 300 comes in contact with the upper GDL 200.

At this time, with the change in the thickness caused when the upper and lower GDLs 200 and 170 are compressed, the external guides 270 are moved by the contraction and relaxation of the guide springs 220 and the upper plate springs 320, and thus the MEA 130 inserted into the external guides 270 can be prevented from being bent.

Consequently, a 5-layer MEA in which the upper GDL 200, the MEA 130 and the lower GDL are sequentially stacked is formed when the respective layers are heated and pressurized for a predetermined period of time by the upper and lower metal plates 300 and 210 supplied with heat from the upper and lower heating plates 340 and 250.

As described above, the heating-pressurizing jig for manufacturing a 5-layer MEA in accordance with the present invention provides the following advantageous effects:

(1) Since the metal plates are formed integrally with the heating plates, the difficulty in increasing the temperature of the metal plates to a normal state every time when manufacturing a plurality of 5-layer MEAs is reduced;

(2) Since the MEA is mounted to the external guides while being spaced apart from the lower guides at predetermined intervals, it is possible to prevent the MEA from being dried, contracted and deformed by the heated metal plates;

(3) Since the lower guides and the upper plate supports are elastically supported by the springs, respectively, the external guides can actively cope with the change in the thickness in real time caused when the upper and lower GDLs are compressed, thus preventing the MEA from being bent; and

(4) When the sizes of the MEA and GDL are changed according to the development of a new vehicle model, it is possible to replace only the jig newly designed and manufactured, thus manufacturing the 5-layer MEAs at low cost without the replacement of the press.

The invention has been described in detail with reference to preferred embodiments thereof. However, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A heating-pressurizing jig for manufacturing a 5-layer membrane electrode assembly, the jig comprising:

a lower metal plate installed on the top surface of a lower heating plate, on which a lower gas diffusion layer is stacked;

a lower guide installed on both sides of the lower metal plate to guide the lower gas diffusion layer to a predetermined position accurately;

a guide spring installed below the lower guide to elastically support the lower guide;

an external guide mounted on the top of the lower guide to fix a membrane electrode assembly and an upper gas diffusion layer;

an upper metal plate mounted on the bottom surface of an upper heating plate, which pressurizes the upper gas diffusion layer when a press is moved down; and

an upper plate support installed on both sides of the upper metal plate, which comes in contact with the external guide when the press is moved down.

2. The heating-pressurizing jig for manufacturing a 5-layer membrane electrode assembly of claim 1, wherein the upper plate support is elastically supported by an upper plate spring.

3. The heating-pressurizing jig for manufacturing a 5-layer membrane electrode assembly of claim 1, wherein an insulating material is disposed between the guide spring and the lower heating plate.

4. The heating-pressurizing jig for manufacturing a 5-layer membrane electrode assembly of claim 1, wherein a projection is formed on the bottom of the external guide and an insertion groove corresponding to the projection is formed on the top of the lower guide.