KR100699450B1 - Electrolyte MEMBRANE ELECTRODE ASSEMBLY structure for fuel cell AND FUEL CELL STACK EMPLOYED WITH THE SAME - Google Patents

Abstract

Provided are an electrolyte membrane electrode assembly for a fuel cell, and a fuel cell stack using the assembly which is reduced in weight, is lowered in manufacturing cost. The electrolyte membrane electrode assembly(20) comprises an electrolyte membrane(20A); and first and second net type metal current collectors(20B) whose surface is coated with a catalyst ink and which are compressed on the both sides of the electrolyte membrane. Preferably, an electrode lead pad(20C) is formed integrally at the one side of the first and second net type metal current collectors, and the electrode lead pad is made of a conductive material or a material identical to the current collector.

Description

Electrolyte MEMBRANE ELECTRODE ASSEMBLY structure for fuel cell AND FUEL CELL STACK EMPLOYED WITH THE SAME}

1 is a schematic exploded view for explaining the structure of a fuel cell stack according to a conventional example;

2 is a view showing the structure of an electrolyte membrane-electrode assembly shown in FIG. 1;

3 is a view showing a structure of an electrolyte membrane-electrode assembly for a fuel cell according to a preferred embodiment of the present invention;

4 is a schematic diagram illustrating a unit fuel cell with a fuel cell electrolyte membrane-electrode assembly structure according to the present invention shown in FIG.

5 is a view showing an air breathing 8-cell fuel cell stack structure employing an electrolyte membrane-electrode assembly for a fuel cell according to the present invention.

* Explanation of symbols for main parts of drawings *

10A, 10B: first and second cover members, 12A, 12B: first and second current collectors,

14A: air supply section, 14B: fuel supply section,

16A, 16B: first and second flow path forming members,

18: MEA (electrolyte film-electrode assembly),

18-1, 18-2: 1st, 2nd carbon paper

20: electrolyte membrane-electrode assembly, 20A: electrolyte membrane,

20B: first and second mesh type metal current collectors,

20C: electrode lead pad, 22A, 22B: flow path forming plate,

30A, 20B, 30C, 30D: fuel cell module

32: Cell module separating member.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolyte membrane-electrode assembly structure for fuel cells and an air breathing fuel cell stack employing the structure, and more particularly, to a direct methanol fuel cell (DMFC) or a polymer fuel cell. The present invention relates to an electrolyte membrane-electrode assembly structure using a mesh type metal current collector coated with and coated with a catalyst ink, and to a fuel cell stack employing the electrolyte membrane-electrode assembly structure.

Recently, researches on fuel cells that obtain electrical energy by chemical reaction of fuel have been actively conducted. Since the fuel cell converts chemical energy of fuel directly into electrical energy, it has high energy. As it shows conversion efficiency and emits little pollutants that cause environmental pollution, it is attracting attention as an eco-friendly power generation system.

The fuel cell includes a direct methanol fuel cell (DMFC) that uses methanol as a fuel and a polymer fuel cell. The DMFC generates electricity by reaction between methanol as a fuel and oxygen as an oxidant. As a result, the energy density and power density are considerably high, and there is no need for a specific peripheral device (eg, a reformer), and a power generation device has an advantage of easy storage and supply of fuel.

1 shows a stack structure of a typical direct methanol fuel cell.

According to the fuel cell stack shown in the drawing, the first and second cover members 10A and 10B as end plates for maintaining the physical shape of the corresponding fuel cell are provided.

In addition, current collectors 12A and 12B for collecting current are disposed on inner surfaces of the first and second cover members 10A and 10B, and the current collectors 12A and 12B are used as fuel. First and second flow path forming members (i.e., graphite plates) 16A and 16B on both sides of the MEA (Membrane Electrode Assembly) which generates electricity by supplying methanol and air (oxygen). It is faced through.

Here, for example, an air (oxygen) supply unit 14A for injecting air (oxygen) and a fuel supply unit 14B for supplying fuel are provided on the first cover member 10A, and the second cover member 10B is provided. An air / fuel outlet (not shown) is provided for discharging residual air and fuel.

In addition, screwing is performed on the outer periphery of each component of the corresponding fuel cell cell pack at positions corresponding to the screw fastening holes 10a formed on the outer periphery of the first cover member 10A and the second cover member 10B. The ball is formed to be engaged by the screw.

Preferably, current collector sealing members 12a and 12b are installed inside the first and second current collectors 12A and 12B, and both sides of the MEA 18 may be installed. MEA sealing members 18A, 18B for sealing are provided, and such sealing structures are arranged when sealing for each component is required.

The MEA 18 is formed by hot-pressing first and second carbon papers coated or coated with a catalyst ink on both sides of an electrolyte membrane, and the outer surfaces of the first and second carbon papers. The first and second flow path forming members 16A and 16B faced each other may be formed of, for example, 'carbon' having a flow path for supplying air and fuel so that air (ie, oxygen) and fuel are uniformly supplied to corresponding carbon paper. System plate '.

In this case, when a plurality of fuel cell cells are integrated in a corresponding fuel cell stack, each cell needs to be connected in series or in parallel, and thus, a component requiring flow paths must be formed of a conductive material. Or metal-based materials.

That is, referring to FIG. 2, the structure according to an example of the electrolyte membrane-electrode assembly 18 may include first and second carbons having catalyst ink coated or coated on both sides of an electrolyte membrane 18-1. Carbon Paper 18-2.18-2 is formed by hot pressing.

Here, oxygen and fuel must be supplied to the anode and the cathode of the fuel cell including the electrolyte membrane-electrode assembly 18, and thus oxygen and fuel are supplied to the carbon papers 18-2 and 18-2. In order to supply uniformly, the flow path for supplying the oxygen and the fuel is formed in a conductive plate (ie, a carbon-based plate; not shown) disposed in a large area on the carbon papers 18-2 and 18-2. .

In this case, when a plurality of fuel cell cells are integrated in a corresponding fuel cell stack, each cell needs to be connected in series or in parallel, and thus, a component requiring flow paths must be formed of a conductive material. Or metal-based materials.

Preferably, the fuel cell stack structure is integrated by fastening screws to screw fastening holes 10a, which are representatively represented by the first and second cover members 10A, 10B.

However, in the above-described conventional fuel cell stack structure, a flow path for uniformly supplying oxygen and fuel to the carbon paper 18-2 of the electrolyte membrane-electrode assembly 18 must be formed in the carbon-based plate. In the case of the fuel cell of the configuration, since each cell must be made in series or parallel connection, a carbon-based material or a metal-based conductive plate is required.

Accordingly, the present invention has been made in view of the above-described prior art, and the catalyst ink is directly applied to and coated on a mesh-type metal current collector to hot press through an electrolyte membrane, thereby eliminating the use of carbon paper. It is an object of the present invention to provide a fuel cell stack including the electrolyte membrane-electrode assembly structure for fuel cells, which enables the application of a non-conductive material (for example, plastic).

In order to achieve the above object, according to a preferred embodiment of the present invention, in a fuel cell comprising an electrolyte membrane-electrode assembly (MEA) and a fuel supply unit disposed inside the porous first and second cover members, The electrolyte membrane-electrode assembly is an electrolyte membrane-electrode assembly for a fuel cell including an electrolyte membrane and first and second mesh type metal current collectors formed by coating and coating a catalyst ink on the surface and pressing the two sides of the electrolyte membrane. Is provided.

According to the present invention, an electrode lead pad formed of the same material or conductive material as that of the current collector is integrally formed on one side of the first and second mesh type metal current collectors.

In addition, according to the present invention, in a fuel cell comprising a unit fuel battery cell formed by an electrolyte membrane-electrode assembly disposed inside the porous first and second cover members and a fuel supply unit, the electrolyte membrane-electrode The aggregate is composed of an electrolyte membrane and first and second mesh type metal current collectors formed by coating and coating a catalyst ink on the surface and pressing the both sides of the electrolyte membrane, wherein the first and second mesh type metal current collectors are formed. There is provided a fuel cell stack employing an electrolyte membrane-electrode assembly structure for a fuel cell, which is disposed on the outside and includes first and second non-conductive plates in which air (oxygen) and a flow path of fuel are formed.

Preferably, the non-conductive plate includes a heat-resistant plastic system.

According to another embodiment of the present invention, in a fuel cell stack comprising a fuel cell module formed by an electrolyte membrane-electrode assembly disposed inside the porous first and second cover members and a fuel supply unit, The fuel cell module includes a first and second mesh type metal current collectors formed by pressing and coating catalyst ink on a surface of the fuel cell cell and being pressed on both sides of the electrolyte membrane, and on the outside of the first and second mesh type metal current collectors. And a first and a second non-conductive plate disposed to form a flow path of air (oxygen) and a fuel, and a cell module separation member having ventilation holes formed on each surface between the plurality of fuel cell cell modules. A fuel cell stack employing the electrolyte membrane-electrode assembly structure for a fuel cell is provided.

According to the present invention, an electrode lead pad formed of the same material or conductive material as that of the current collector is provided on one side of the first and second mesh type metal current collectors for serial / parallel connection of the plurality of fuel cell modules. It is formed integrally.

In addition, the non-conductive plate includes a heat-resistant plastic system.

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

3 is a view showing a structure of an electrolyte membrane-electrode assembly for a fuel cell according to a preferred embodiment of the present invention.

Referring to the drawings, the electrolyte membrane-electrode assembly 20 according to the present invention is formed by hot pressing the first and second mesh type metal current collectors 20B and 20B on both sides of the electrolyte membrane 20A. Electrode lead pads formed by extending a part of the corresponding metal current collector or integrally formed by using separate members at predetermined positions of the upper ends of the first and second mesh type metal current collectors 20B and 20B. 20C will be equipped.

Preferably, the electrolyte membrane-electrode assembly 20 has the first and second mesh type when the first and second mesh type metal current collectors 20B and 20B are compressed to the electrolyte membrane 20A. When the metal current collectors 20B and 20B are set as the cathodes in which one side is in contact with the air, the other side functions as the anode for contact with the fuel, so that the electrode lead pads 20C are staggered. By arranging the first and second mesh type metal current collectors 20B and 20B, the series or parallel connection of a plurality of fuel cell cells is achieved only by the electrical connection of the respective electrode lead pads 20C.

FIG. 4 is a schematic diagram illustrating a unit fuel battery cell using a single-electrode electrolyte membrane-electrode assembly according to the present invention shown in FIG. 3.

Referring to the drawings, in the case of the fuel cell cell employing the electrolyte membrane-electrode assembly 20, since the mesh-type metal current collector 20B has electrical conductivity, a flow path is formed in which oxygen or fuel flow paths are formed. The plates 22A and 22B may be formed of a non-conductive material, unlike the conductive plate of the carbon-based material or the metal-based material in FIG. 1. Preferably, the non-conductive material may be plastic.

Here, as the plastic material, since the operating temperature of the fuel cell is generally about 80 ° C. at room temperature, a heat resistant material such as PC (Polycarbonate), PC / ABS (Acrylonitrile Butadiene Styrene), or PBT (Polybutylene Terephthalate) is preferable.

Moreover, the use of such plastic material is advantageous because it is cheaper and lighter than carbon-based or metal-based materials, and the flow path can be easily formed as compared with the carbon-based or metal-based plates.

5 is a diagram illustrating an air breathing 8-cell fuel cell stack employing an electrolyte membrane-electrode assembly according to the present invention.

Typically, the fuel cell stack is roughly classified into an active type and a passive type according to a method of supplying air (oxygen) and fuel. The electrolyte membrane electrode assembly according to the present invention (20 in FIG. 3). In the case of adopting the structure of), both oxygen and fuel are supplied in an active manner, oxygen is supplied in a passive manner, fuel is supplied in an active manner, oxygen is supplied in an active manner, and fuel is passive. It is possible to apply the method of supplying the gas and the method of supplying oxygen and fuel in a passive manner.

That is, in the case of the conventional fuel cell system illustrated in FIG. 1, both oxygen and fuel are supplied in an active manner, whereas in the present invention, the above four types of selective application are possible. The configuration shown in Fig. 5 is an example of application to an eight-cell structure in which both oxygen and fuel are supplied in a passive manner.

Referring to FIG. 5, a cell module is formed with a fuel supply unit 30A interposed in the middle of the fuel cells 20 and 20 by the electrolyte membrane-electrode assembly of FIG. 3, the fuel supply unit 30A. The fuel container 30b is provided inside the hexahedral housing 30a, and a fuel injection hole 30c for fuel injection is formed at a predetermined position.

When a plurality of cell modules 30A, 30B, 30C, and 30D having the above-described configuration are provided, a plurality of cell holes 30a are formed on four sides between the cell modules 30A, 30B, 30C, and 30D. The cell module separating member 32 is disposed, and the first and second cover members 34A and 30B having a plurality of vent holes 34a are disposed at the other sides of the outermost cell modules 30B and 30D.

Therefore, the air passing through the vent hole 32a of the cell module separating member 32 is connected to any one side of the mesh type metal current collector (20B in FIG. 2) forming each of the cell modules 30A, 30B, 30C, and 30D. In addition to the contact with the fuel is supplied to the other side of the chemical reaction of the fuel is induced to generate electricity.

Here, the series or parallel connection of each cell module 30A, 30B, 30C, 30D is achieved by the connection of the electrode lead pads 20C of the mesh-type metal current collector 20B.

On the other hand, the present invention is not limited to the above examples and various changes and modifications can be carried out within the scope not departing from the technical gist and gist of the invention.

As described above, according to the fuel cell electrolyte membrane-electrode assembly structure and the fuel cell stack employing the structure according to the present invention, the electrolyte membrane-electrode assembly (MEA) is coated with a catalyst ink on the surface of the electrolyte membrane and Since it is formed by hot pressing of the coated mesh metal current collector, the flow path forming plate on which the air (oxygen) and fuel flow paths are formed does not necessarily need to be formed of a conductive material of metal or carbon, and the flow path is easily formed. The overall weight and manufacturing cost savings are achieved.

In addition, the series or parallel connection of a plurality of fuel cell cells is achieved by series or parallel connection of electrode lead pads integrally formed in a mesh metal current collector.

Furthermore, a plurality of fuel cell cell modules configured to interpose the mesh metal current collector with an electrolyte membrane are disposed, and an air breathing fuel cell stack is formed by interposing a cell module separation member having vent holes formed on each side between each cell module. It is also possible.

Claims (7)

A fuel cell comprising an electrolyte membrane-electrode assembly (MEA) disposed inside a porous first and second cover members and a fuel supply unit, The electrolyte membrane electrode assembly is an electrolyte membrane, An electrolyte membrane-electrode assembly for fuel cells, comprising: first and second mesh type metal current collectors formed by coating and coating a catalyst ink on a surface of the catalyst membrane and pressing the two sides of the electrolyte membrane. The method of claim 1, Electrolyte membrane-electrode assembly for fuel cell, characterized in that the electrode lead pad formed of the same material or conductive material as the current collector is integrally formed on one side of the first and second mesh type metal current collector. A fuel cell comprising a unit fuel battery cell formed by an electrolyte membrane-electrode assembly disposed inside porous first and second cover members, and a fuel supply unit, The electrolyte membrane-electrode assembly is composed of an electrolyte membrane and first and second mesh type metal current collectors formed by coating and coating a catalyst ink on a surface thereof and pressing the two sides of the electrolyte membrane. And a first electrode and a second non-conductive plate disposed outside the first and second mesh type metal current collectors and having a flow path of air (oxygen) and a fuel. A fuel cell stack employing an electrode assembly structure. The method of claim 3, The non-conductive plate is a fuel cell stack employing an electrolyte membrane-electrode assembly structure for a fuel cell, characterized in that it comprises a heat-resistant plastic system. In a fuel cell stack comprising a fuel cell module formed by an electrolyte membrane-electrode assembly disposed inside the porous first and second cover members and a fuel supply unit, The fuel cell module includes a first and second mesh type metal current collectors formed by pressing and coating a catalyst ink on a surface of the fuel cell cell and being pressed on both sides of the electrolyte membrane, and on the outside of the first and second mesh type metal current collectors. A first and a second non-conductive plate disposed to form a flow path of air (oxygen) and fuel, A fuel cell stack employing an electrolyte membrane-electrode assembly structure for a fuel cell, wherein a plurality of fuel cell cell modules are provided with cell module separation members having vent holes formed on respective surfaces thereof. The method of claim 5, One side of the first and second mesh type metal current collectors may be integrally formed with electrode lead pads formed of the same material or conductive material as the current collectors for serial / parallel connection of the plurality of fuel cell modules. A fuel cell stack employing an electrolyte membrane-electrode assembly structure for fuel cells. The method of claim 5, The non-conductive plate is a fuel cell stack employing an electrolyte membrane-electrode assembly structure for a fuel cell, characterized in that it comprises a heat-resistant plastic system.

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