KR20100085300A - A method of forming catalyst layer for fuel cell, a membrane electrode assembly and a fuel cell having catalyst layer manufactured by the same - Google Patents

Abstract

PURPOSE: A method for forming a catalyst layer for a fuel cell is provided to reduce consumption amount of catalyst materials by forming the catalyst layer only on an electrode substrate corresponding to a channel pattern of a bipolar plate. CONSTITUTION: A method for forming a catalyst layer for a fuel cell comprises a step(210) of preparing an electrode substrate and a step(220) of forming the catalyst layer only on a position corresponding to a channel which is formed on a bipolar plate. A membrane electrode assembly for a fuel cell includes an anode, a cathode, and a polymer electrolyte membrane which is arranged between the anode and the cathode. The anode includes a firs catalyst layer and the cathode includes a second catalyst layer.

Description

A method of forming catalyst layer for fuel cell, a membrane electrode assembly and a fuel cell having catalyst layer manufactured by the same}

The present invention relates to a method of forming a catalyst layer for a fuel cell, a membrane-electrode assembly having a catalyst layer prepared accordingly, and a fuel cell. More specifically, the present invention reduces the consumption of the catalyst material by reducing the cost of the catalyst material by forming the catalyst layer only on the electrode substrate of the portion corresponding to the flow path pattern of the bipolar plate. A method of forming a catalyst layer for a fuel cell, a membrane-electrode assembly having a catalyst layer prepared accordingly, and a fuel cell are provided.

A fuel cell is a power generation system that directly converts the chemical reaction energy of hydrogen and oxygen contained in hydrocarbon-based materials such as methanol, ethanol and natural gas into electrical energy. Among these, the polymer electrolyte fuel cell (PEMFC), which is being developed recently, has superior output characteristics compared to other fuel cells, has a low operating temperature, fast start-up and response characteristics, and a mobile power source such as an automobile. Of course, it has a wide range of applications, such as distributed power supply for homes, public buildings and small power supply for electronic devices.

The above-described PEMFC basically includes a stack, a reformer, a fuel tank, a fuel pump, and the like to constitute a system. The stack forms the body of the fuel cell, and the fuel pump supplies the fuel in the fuel tank to the reformer. The reformer reforms the fuel to generate hydrogen gas and supplies the hydrogen gas to the stack. Thus, the PEMFC supplies fuel in the fuel tank to the reformer by operation of a fuel pump, reforming the fuel in the reformer to generate hydrogen gas, and electrochemically reacting the hydrogen gas and oxygen in a stack to generate electrical energy. Let's do it.

On the other hand, the fuel cell may employ a direct methanol fuel cell (DMFC) method that can supply a liquid methanol fuel directly to the stack. Such a direct methanol fuel cell fuel cell, unlike the polymer electrolyte fuel cell, the reformer is excluded.

In such a fuel cell system, a stack that substantially generates electricity includes several to several unit cells including a membrane electrode assembly (MEA) and a separator or a bipolar plate. It has a stacked structure of ten. The membrane-electrode assembly has a structure in which an anode (anode) electrode and a cathode (cathode) electrode (hereinafter referred to as "electrode") are bonded to each other with a polymer electrolyte membrane interposed therebetween.

FIG. 1A is a cross-sectional view of a fuel cell electrode according to the prior art, and FIG. 1B schematically illustrates a fuel cell including a membrane-electrode assembly according to the prior art.

1A and 1B, the membrane-electrode assembly (MEA) 10 includes an anode electrode 100; Cathode electrode 100 '; And a polymer electrolyte membrane 110 disposed between the anode electrode 100 and the cathode electrode 100 '. Each electrode 100, 100 ′ is an electrode substrate 101, 101 ′; And catalyst layers 105 and 105 'formed on the electrode substrates 101 and 101'. The catalyst layers 105 and 105 'are coated with a nanocarbon layer, a catalyst (for example, platinum or ruthenium-platinum alloy) deposited on the surface of the electrode substrate 101 and 101', and a Nafion solution. Obtained. Here, the electrode substrates 101 and 101 'serve as a support for supporting the electrodes 100 and 100' and also serve as a passage for delivering fuel and oxygen gas to the catalyst layer, and include carbon paper or carbon cloth ( carbon cloth). The anode electrode 100 and the cathode electrode 100 'are formed by injecting a cathode and a cathode gas diffusion medium into the electrode substrates 101 and 101' made of carbon paper or carbon cloth, respectively. In addition, electrode substrates 101 and 101 'made of carbon paper or carbon cloth are commonly referred to as a gas diffusion layer (GDL) (hereinafter referred to as a "gas diffusion layer"), and have a thickness of approximately 10 to 1000 mu m. The prior art and FIGS. 1 and 2 described above are filed as No. 10-2004-0050773 dated June 30, 2004 under the name of "Invention for Fuel Cell, Fuel Cell and Fuel Electrode Manufacturing Method Including The Same". , Korean Patent No. 057877, registered May 4, 2006. Reference numerals 120 and 120 ′ shown in FIG. 1B denote separators or bipolar plates used to stack a plurality of membrane-electrode assemblies (MEA) 10 described above, respectively.

FIG. 1C is a schematic perspective view of the bipolar plate shown in FIG. 1B, and FIG. 1D is a schematic perspective view of an electrode composed of an electrode substrate and a catalyst layer on the bipolar plate shown in FIG. 1C.

1C and 1D, in the bipolar plates 120 and 120 ′, oxygen or hydrogen is introduced at the inlet A and discharged to the outlet B along the flow paths 122 and 122 ′, respectively. Here, the oxygen or hydrogen flow paths 122 and 122 'are exemplarily shown in a zigzag shape, but in practice, various flow paths (eg, a circular spiral shape, a rectangular spiral shape, or a flow path near the inlet A and the outlet B) are shown. The width of the narrow, and the zigzag shape such that the width of the flow path toward the central portion is wider).

Meanwhile, the catalyst layers 105 and 105 'described above are formed on the electrode substrates 101 and 101' made of carbon paper or carbon cloth corresponding to the bipolar plates 120 and 120 'having the flow paths 122 and 122' shown in FIG. 1C. To this end, in the prior art, the entire surface coating method using a slit die (not shown) has been used to form the catalyst layers 105 and 105 'on the electrode substrates 101 and 101'. Such a slit die and a front coating method using the same have been filed by the applicant of the Korean Patent Application No. 2007-0083382 on August 20, 2007 under the name of the invention "printing roll forming apparatus and printing apparatus having the same". It is described in detail in Korean Patent No. 0853218, registered August 31, 2008.

However, when the entire surface coating method using the slit die according to the prior art is used, since the entire surface is coated on the electrode bases 101 and 101 ', the catalyst layers 105 and 105' are connected to the flow paths 122 and 122 'of the bipolar plates 120 and 120'. The catalyst layers 105 and 105 are also unnecessarily applied to portions on the electrode bases 101 and 101 'corresponding to the spaces 124 and 124' between the flow paths 122 and 122 '(hereinafter referred to as' dead spaces'). Accordingly, a problem arises in that the material of the catalyst layers 105, 105 'is wasted and the cost is increased. In particular, since the catalyst layer contains an expensive platinum catalyst, a problem arises in that the cost increases further.

In addition, when the flow paths 122 and 122 'have a circular spiral shape, for example, in order to reduce the frictional force due to the change of direction when passing oxygen or hydrogen gas, the catalyst layers 105 and 105' are always in the front coating method using a slit die. Since only the rectangular shape is applied, the above-described dead space becomes larger.

In addition, the fuel cell generally has a rectangular parallelepiped shape, and a cylindrical shape is also possible. However, in some cases, shapes other than the rectangular parallelepiped (for example, only one side of the rectangular parallelepiped or the shape of the upper and lower portions of the rectangular parallelepiped may be required). In this case, the above-described prior art of the front coating method is very difficult to implement the shape of the various fuel cells . As a result, applications requiring the use of fuel cells are very limited.

Therefore, a new method for solving the above-mentioned problems of the prior art is required.

The present invention is to solve the above-mentioned problems of the prior art, by forming the catalyst layer only on the electrode substrate of the portion corresponding to the flow path pattern of the bipolar plate, the consumption of the catalyst material is reduced, the cost is reduced, the required fuel cell It is to provide a method for forming a catalyst layer for a fuel cell that can be produced irrespective of the shape, a membrane-electrode assembly with a catalyst layer prepared accordingly, and a fuel cell.

According to a first aspect of the present invention, there is provided a method of forming a catalyst layer for a fuel cell, the method comprising: a) preparing an electrode substrate; And b) forming a catalyst layer only at a position corresponding to a flow path formed in the bipolar plate on the electrode substrate.

According to a second aspect of the present invention, there is provided a fuel cell membrane-electrode assembly (MEA), comprising: an anode electrode; Cathode electrode; And a polymer electrolyte membrane disposed between the anode electrode and the cathode electrode, wherein the anode electrode is a cathode electrode substrate; And a first catalyst layer formed on the cathode electrode substrate, wherein the cathode electrode is a cathode electrode substrate; And a second catalyst layer formed on the cathode electrode substrate, wherein the first and second catalyst layers are formed only at positions corresponding to the first and second flow paths formed on the first and second bipolar plates, respectively. An electrode assembly (MEA) is featured.

According to a third aspect of the present invention, there is provided a fuel cell comprising: a plurality of membrane-electrode assemblies (MEAs); And a plurality of bipolar plates used to stack the plurality of membrane-electrode assemblies (MEA), each of the plurality of membrane-electrode assemblies (MEA) comprising an anode electrode; Cathode electrode; And a polymer electrolyte membrane disposed between the anode electrode and the cathode electrode, wherein the anode electrode is a cathode electrode substrate; And a first catalyst layer formed on the cathode electrode substrate, wherein the cathode electrode is a cathode electrode substrate; And a second catalyst layer formed on the cathode electrode substrate, wherein the first and second catalyst layers are formed only at positions corresponding to the first and second flow paths formed on the first and second bipolar plates, respectively. I am doing it.

In the method for forming a catalyst layer for a fuel cell according to the present invention, a membrane-electrode assembly with a catalyst layer prepared according to the present invention, and a fuel cell, the following advantages are achieved.

1. Since the catalyst layer is not formed on the dead space, the material and cost of the catalyst layer are significantly reduced. In addition, an advantage is achieved that the cost savings effect is very large when expensive platinum catalysts are used.

2. The catalyst layer can be formed regardless of the shape of the flow path.

3. It is possible to manufacture fuel cell in desired shape, so it can be applied to various applications.

Further advantages of the present invention can be clearly understood from the following description with reference to the accompanying drawings, in which like or similar reference numerals denote like elements.

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings of the present invention.

FIG. 2A is a flowchart illustrating a method of forming a catalyst layer for a fuel cell according to an embodiment of the present invention, and FIG. 2B is manufactured according to the method for forming a catalyst layer for a fuel cell according to an embodiment of the present invention shown in FIG. 2A. FIG. 2C is a perspective view schematically illustrating an electrode having a catalyst layer, and FIG. 2C is a cross-sectional view of an electrode having a catalyst layer manufactured according to a method of forming a catalyst layer for a fuel cell according to an exemplary embodiment of the present invention illustrated in FIG. 2B.

2A to 2C, a method 200 of forming a catalyst layer for a fuel cell according to an embodiment of the present invention includes preparing an electrode substrate 201, 201 '(210); And forming the catalyst layers 205 and 205 'only at positions corresponding to the flow paths 222 and 222' formed on the bipolar plates 220 and 220 'on the electrode substrates 201 and 201'. That is, in the method 200 for forming a catalyst layer for a fuel cell according to an embodiment of the present invention, the catalyst layers 205 and 205 'are not formed at positions corresponding to the dead spaces 224 and 224' on the bipolar plates 220 and 220 '.

In order to perform the step 220 of forming the catalyst layers 205 and 205 'only at positions corresponding to the flow paths 222 and 222' formed on the bipolar plates 220 and 220 'on the electrode substrates 201 and 201', the slit die may be used. Unlike the prior art, an inkjet printing apparatus (not shown) is used. Such an inkjet printing apparatus is filed, for example, on February 25, 2008 by the present applicant under the name of the invention "the cleaning apparatus of the head for inkjet printing apparatus, and the head and inkjet printing apparatus for inkjet printing apparatus having the same". It is described in detail in Korean Patent Application No. 10-2008-0016795. The inkjet printing apparatus itself is a known technique, but using such an inkjet printing apparatus, the catalyst layers 205 and 205 'are formed only at positions corresponding to the flow paths 222 and 222' formed on the bipolar plates 220 and 220 'on the electrode substrates 201 and 201'. On the other hand, it is possible not to be formed at a position corresponding to the dead space (224, 224 ').

In addition, the flow paths 222 and 222 'formed in the bipolar plates 220 and 220' have a circular spiral shape, a rectangular spiral shape, or a narrow width of the flow path in the vicinity of the inlet and the outlet, as well as the usual zigzag shape. It can have arbitrary shapes, such as a zigzag shape in which the width | variety of a flow path becomes wide. In this case, the inkjet printing apparatus used in the method 200 for forming a catalyst layer for a fuel cell according to an embodiment of the present invention sprays ink so as to form only a pattern of the catalyst layers 205 and 205 'corresponding to an arbitrary shape of the flow paths 222 and 222'. The program can be set up in advance. In this manner, even if the flow paths 222 and 222 'have any shape, the catalyst layers 205 and 205' are always formed only at positions corresponding to the flow paths 222 and 222 ', and are not formed at positions corresponding to the dead spaces 224 and 224'. It is possible to form catalyst layers 205 and 205 'on the electrode substrates 201 and 201'.

Meanwhile, the membrane-electrode assembly (MEA) according to the present invention is a membrane-electrode assembly (MEA) according to the prior art shown in FIGS. 1A and 1B except for the catalyst layers 205 and 205 'shown in FIG. 2B or 2C. It is substantially the same as (10).

More specifically, referring to FIGS. 1A, 1B, 2B, and 2C, a membrane-electrode assembly (MEA) according to the present invention may include an anode electrode 100; Cathode electrode 100 '; And a polymer electrolyte membrane 110 disposed between the positive electrode 100 and the negative electrode 100 ', wherein the positive electrode 100 includes a positive electrode base 201; And a first catalyst layer 205 formed on the anode electrode substrate 201, wherein the cathode electrode 100 ′ is a cathode electrode substrate 201 ′; And a second catalyst layer 205 'formed on the cathode electrode substrate 201', wherein the first and second catalyst layers 205 and 205 'are formed on the first and second bipolar plates 220 and 220', respectively. It is formed only in the positions corresponding to the first and second flow paths (222, 222 ').

In addition, the fuel cell according to the present invention comprises a plurality of membrane-electrode assemblies (MEA); And a plurality of bipolar plates used to stack the plurality of membrane-electrode assemblies (MEAs). Here, each of the plurality of membrane-electrode assemblies MEA includes an anode electrode 100; Cathode electrode 100 '; And a polymer electrolyte membrane 110 disposed between the positive electrode 100 and the negative electrode 100 ', wherein the positive electrode 100 includes a positive electrode base 201; And a first catalyst layer 205 formed on the anode electrode substrate 201, wherein the cathode electrode 100 ′ is a cathode electrode substrate 201 ′; And a second catalyst layer 205 'formed on the cathode electrode substrate 201', wherein the first and second catalyst layers 205 and 205 'are formed on the first and second bipolar plates 220 and 220', respectively. It is formed only in the positions corresponding to the first and second flow paths (222, 222 ').

The first and second catalyst layers 205 and 205 'used in the membrane-electrode assembly (MEA) and the fuel cell according to the present invention described above are formed by an inkjet printing apparatus, respectively.

On the other hand, the catalyst used in the catalyst layers 205, 205 'of the present invention, for example, in addition to the platinum or ruthenium-platinum alloy of the prior art Palladium or conductive ink may be used.

Using the above-described method of forming a catalyst layer for a fuel cell according to the present invention, a membrane-electrode assembly with a catalyst layer and a fuel cell prepared according to the present invention, the material and cost of the catalyst layer are significantly reduced, and the catalyst layer is independent of the shape of the flow path. Can be formed and the fuel cell can be applied to various applications.

Various modifications may be made by those skilled in the art without departing from the spirit and scope of the invention as defined by the following claims. It is not. Therefore, the scope of the present invention should not be limited by the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

1A is a cross-sectional view of a fuel cell electrode according to the prior art.

1B is a schematic view of a fuel cell including a membrane-electrode assembly according to the prior art.

FIG. 1C is a schematic perspective view of the bipolar plate shown in FIG. 1B.

FIG. 1D is a schematic perspective view of an electrode composed of an electrode substrate and a catalyst layer on the bipolar plate shown in FIG. 1C.

2A is a flowchart illustrating a method of forming a catalyst layer for a fuel cell according to an embodiment of the present invention.

FIG. 2B is a perspective view schematically illustrating an electrode having a catalyst layer manufactured according to a method of forming a catalyst layer for a fuel cell according to an embodiment of the present invention illustrated in FIG. 2A.

FIG. 2C is a cross-sectional view of an electrode having a catalyst layer manufactured according to a method of forming a catalyst layer for a fuel cell according to an embodiment of the present invention shown in FIG. 2B.

Claims (12)

In the method of forming a catalyst layer for a fuel cell, a) preparing an electrode substrate; And b) forming a catalyst layer only at a position corresponding to the flow path formed in the bipolar plate on the electrode substrate; Method for forming a catalyst layer for a fuel cell comprising a. The method of claim 1, The method of forming a catalyst layer for a fuel cell, wherein step b) is performed using an inkjet printing apparatus. The method according to claim 1 or 2, And the flow path is any one of a zigzag shape, a circular spiral shape, a rectangular spiral shape, or a zigzag shape in which the width of the flow path is narrow in the vicinity of the inlet and the outlet, and the width of the flow path becomes wider toward the center portion. The method according to claim 1 or 2, The catalyst used in the catalyst layer is a method for forming a catalyst layer for a fuel cell, any one of platinum, ruthenium-platinum alloy, palladium, and conductive ink. In the fuel cell membrane-electrode assembly (MEA), An anode electrode; Cathode electrode; And A polymer electrolyte membrane disposed between the anode electrode and the cathode electrode Including, The anode electrode is a cathode electrode substrate; And a first catalyst layer formed on the anode electrode substrate, The cathode electrode is a cathode electrode substrate; And a second catalyst layer formed on the cathode electrode substrate, The first and second catalyst layers are formed only at positions corresponding to the first and second flow paths formed in the first and second bipolar plates, respectively. Membrane-electrode assembly for fuel cells. The method of claim 5, The fuel cell membrane-electrode assembly (MEA), wherein the first catalyst layer and the second catalyst layer are each formed by an inkjet printing apparatus. The method according to claim 5 or 6, Each of the first flow path and the second flow path has a zigzag shape, a circular spiral shape, a rectangular spiral shape, or a zigzag shape in which the width of the flow path is narrow near the entrance and the exit, and the width of the flow path becomes wider toward the center portion. One of the membrane-electrode assembly for fuel cells (MEA). The method according to claim 5 or 6, The catalyst used in the first catalyst layer and the second catalyst layer, respectively, one of platinum, ruthenium-platinum alloy, palladium, and a conductive ink membrane-electrode assembly for fuel cells (MEA). In fuel cells, A plurality of membrane-electrode assemblies (MEAs); And A plurality of bipolar plates used to stack the plurality of membrane-electrode assemblies (MEA) Including, The plurality of membrane-electrode assemblies (MEA) are each An anode electrode; Cathode electrode; And A polymer electrolyte membrane disposed between the anode electrode and the cathode electrode Including; The anode electrode is a cathode electrode substrate; And a first catalyst layer formed on the anode electrode substrate, The cathode electrode is a cathode electrode substrate; And a second catalyst layer formed on the cathode electrode substrate, The first and second catalyst layers are formed only at positions corresponding to the first and second flow paths formed in the first and second bipolar plates, respectively. Fuel cell. The method of claim 9, The first catalyst layer and the second catalyst layer are each formed by an inkjet printing device. The method according to claim 9 or 10, The first flow path and the second flow path each have a zigzag shape, a circular spiral shape, a rectangular spiral shape, or a zigzag shape in which the flow path is narrow in the vicinity of the inlet and the outlet, and the width of the flow path is widened toward the center portion. One fuel cell. The method according to claim 9 or 10, And a catalyst used in each of the first catalyst layer and the second catalyst layer is any one of platinum, ruthenium-platinum alloy, palladium, and conductive ink.

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