KR20070072989A - Direct oxidation fuel cell - Google Patents

Abstract

Provided is a direct oxidation fuel cell in which the water condensed at the air ventilation hole of a cathode member is easily absorbed and discharged, thereby improving efficiency and reliance. The direct oxidation fuel cell comprises at least one electricity generation unit(90) which comprises a membrane electrode assembly(10), and an anode member(40) and a cathode member(60) closely arranged at the both sides of the membrane electrode assembly, and generate an electric energy and water by the reaction of fuel and oxygen, wherein the electricity generation unit comprises further an adsorption member(70) which is formed at the cathode member to absorb water and to discharge the absorbed water. The adsorption member is made of a microfilament yarn.

Description

Direct Oxidation Fuel Cell {DIRECT OXIDATION FUEL CELL}

1 is an exploded perspective view showing an exemplary embodiment of a direct oxidation fuel cell according to the present invention.

2 is a cross-sectional view of the combined configuration of FIG.

3 is an exploded perspective view showing another exemplary embodiment of a direct oxidation fuel cell according to the present invention.

4 is a cross-sectional view of the coupling cross-sectional view of FIG.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct oxidation fuel cell, and more particularly, to a direct oxidation fuel cell that generates electrical energy by direct reaction of fuel and oxygen.

As is known, a fuel cell is configured as a power generation system that directly converts chemical reaction energy of hydrogen contained in a hydrocarbon-based fuel and oxygen supplied separately into electrical energy.

Such fuel cells are largely referred to as Polymer Electrolyte Membrane Fuel Cells (PEMFCs), and Direct Oxidation Fuel Cells (PEMFCs). : DMFC) ").

The polymer electrolyte fuel cell is configured as a fuel cell body (hereinafter referred to as "stack" for convenience) called a stack, and is composed of hydrogen gas supplied from a reformer and air supplied by operation of an air pump or fan. It consists of a structure that generates electrical energy through an electrochemical reaction. Here, the reformer functions as a fuel treatment apparatus for reforming fuel to generate hydrogen gas from the fuel, and supplying the hydrogen gas to the stack.

Unlike the polymer electrolyte type fuel cell, the direct oxidation type fuel cell is directly supplied with alcohol, which is a fuel, without using hydrogen gas. The direct energy fuel cell is supplied by the electrochemical reaction of hydrogen contained in the fuel and separately supplied air. It is made as a structure for generating a. Such a direct oxidation fuel cell has a passive method of providing air at no load without depending on a pump or a fan, and an active air provided by a driving force of the pump or a fan, depending on the type of composition thereof. It can be configured as a way.

Among these, the passive oxidation fuel cell by the passive method has an anode plate and a cathode disposed in close contact with both sides of the membrane-electrode assembly (hereinafter referred to as "MEA"). It is configured as a plate. Here, the cathode plate is installed to be exposed to the atmosphere with a plurality of vents for circulating air to the MEA.

However, the conventional passive oxidation fuel cell according to the passive method generates water in the form of water vapor through a reduction reaction of air by MEA. As the cathode plate is configured to be exposed to the atmosphere, water in the form of water vapor forms the cathode plate. In the vents, they condense in contact with the atmosphere at a relatively low temperature, and these condensate agglomerates in the vents of the cathode plate, blocking these vents by the action of surface tension. As a result, the conventional direct oxidation fuel cell has a problem in that air in the air is blocked by condensed water and thus cannot be smoothly supplied to the vent holes of the cathode plate, thereby degrading performance efficiency and reliability of the entire fuel cell.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object thereof is to provide a direct oxidation type fuel cell that can easily discharge the water agglomerated in the vents of the cathode plate.

In order to achieve the above object, a direct oxidation fuel cell according to an exemplary embodiment of the present invention includes an anode member and a cathode member closely disposed on both sides of a membrane-electrode assembly so that fuel and oxygen At least one electricity generating unit generating electrical energy and moisture by a reaction, wherein the electricity generating unit includes an adsorption member formed on the cathode member to absorb and discharge the moisture, and the adsorption member is a microfiber fiber. It is formed as.

The direct oxidation fuel cell may be configured such that the cathode member is exposed to the atmosphere.

In the direct oxidation fuel cell, the adsorption member may be disposed in close contact with the exposed surface of the cathode member.

In the direct oxidation fuel cell, the adsorption member may be interposed between the cathode member and the membrane-electrode assembly.

In the direct oxidation fuel cell, the adsorption member may be formed as a sheet having a plurality of pores.

In the direct oxidation fuel cell, the cathode member may include a plurality of vents for circulating air to the membrane-electrode assembly. In this case, the suction member may include a plurality of holes in communication with the vent holes.

In the direct oxidation type fuel cell, the anode member includes a flow path for distributing the fuel, and the flow path may be formed as a meander shape.

The direct oxidation fuel cell may be configured as a current collector plate in which the anode member and the cathode member collect currents having different polarities.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

1 is an exploded perspective view showing an exemplary embodiment of a direct oxidation fuel cell according to the present invention, Figure 2 is a combined cross-sectional view of FIG.

Referring to the direct oxidation fuel cell 100 according to an embodiment of the present invention with reference to this figure, the direct oxidation fuel cell 100 generates electrical energy by the electrochemical reaction of fuel and oxygen, It is comprised as a power generation system which provides this electric energy to a predetermined load.

The direct oxidation fuel cell 100 is directly supplied with alcohol-based fuels such as methanol and ethanol, and air in the atmosphere, and the electrical energy is reduced by the oxidation reaction of hydrogen contained in the fuel and the oxygen reaction contained in the air. It can be configured as a conventional passive type Direct Methanol Fuel Cell (DMFC) to generate a.

More specifically, the direct oxidation type fuel cell 100 according to the present embodiment is supplied with fuel by a fuel supply device (not shown in the drawing) or a capillary action of fuel or a difference in concentration of fuel. And at least one electricity generating unit (90) for receiving the air in the atmosphere by the air and generating the electrical energy by the oxidation reaction of the fuel and the air and the reduction reaction.

Preferably, the direct oxidation fuel cell 100 according to the present embodiment is configured as a plate type fuel cell configured by arranging the electricity generating unit 90 in a planar manner. In the drawings, the fuel cell 100 according to the present embodiment is shown as a single electricity generating unit 90, but this is merely a simplified drawing for the sake of illustrating the present invention, and alternatively the electricity generating unit ( The fuel cell 100 according to the present embodiment can also be constituted by providing a plurality of 90s and arranging these electricity generating units 90 continuously.

In the direct oxidation fuel cell 100 as described above, the electricity generating unit 90 is basically a membrane-electrode assembly (hereinafter referred to as "MEA") 10 and And an anode member 40 and a cathode member 60 which are disposed in close contact with both sides of the MEA 10 at the center thereof. At this time, the electricity generating unit 90 may be formed as a structure packaged by a predetermined case (not shown in the figure) while being pressed closely by a conventional fastening means (not shown in the figure).

In the present embodiment, the MEA 10 forms the first electrode layer 11 on one surface, the second electrode layer 12 on the other surface, and a membrane 13 between the electrode layers 11 and 12. ) Is formed. In this case, the anode member 40 is disposed in close contact with the first electrode layer 11, and the cathode member 60 is disposed in close contact with the second electrode layer 12.

Here, the first electrode layer 11 is supplied with fuel through the anode member 40 and oxidizes hydrogen contained in the fuel to separate the hydrogen into electrons and hydrogen ions. The membrane 13 functions to transfer the hydrogen ions separated from the hydrogen in the first electrode layer 11 to the second electrode layer 12. In addition, the second electrode layer 12 functions to reduce moisture and heat by reacting electrons, hydrogen ions, and oxygen provided through the cathode member 60 received from the first electrode layer 11.

In this embodiment, the anode member 40 is made of a plate-type conductive metal material disposed in close contact with the first electrode layer 11 of the MEA 10, and the fuel is supplied to the first electrode layer 11 of the MEA 10. In addition to the function of distributing and supplying the electrons, the electrons separated from the hydrogen in the first electrode layer 11 are transferred to the cathode member 60 which will be described later.

To this end, the anode member 40 includes a flow path 42 for circulating fuel to the first electrode layer 11 of the MEA 10, and the flow path 42 is the first electrode layer 11 of the MEA 10. It is formed in the form of a channel in the region corresponding to). Preferably, the flow path 42 is disposed in a straight line at a predetermined interval on one surface of the anode member 40 facing the first electrode layer 11 of the MEA 10 and alternately connects both ends thereof in a meandering manner. It is formed as a meander.

In addition, the anode member 40 functions as a conductor for moving electrons to the cathode member 60 as described above, and the current collector plate 41 for collecting current having a different polarity from the cathode member 60. It can be configured as.

In the present embodiment, the cathode member 60 is made of a plate-type conductive metal material disposed in close contact with the second electrode layer 12 of the MEA 10 while being exposed to the atmosphere. The cathode member 60 functions as a conductor that receives electrons from the anode member 40 in addition to a function of distributing and supplying air in the atmosphere to the second electrode layer 12 of the MEA 10 by natural diffusion or convection of the air. Will be

To this end, the cathode member 60 has a cathode member 60 with respect to a region corresponding to the second electrode layer 12 of the MEA 10 to distribute air in the atmosphere to the second electrode layer 12 of the MEA 10. A plurality of vent holes (63) penetrating the plate is formed.

In addition, the cathode member 60 functions as a conductor for receiving electrons from the anode member 40 as described above, and as the current collector plate 61 for collecting current having a different polarity from the anode member 40. Can be configured.

In the action of the direct oxidation fuel cell 100 according to the present embodiment configured as described above, the second electrode layer 12 of the MEA 10 generates water in the form of water vapor by a reduction reaction of oxygen. As the member 60 is configured to be exposed to the atmosphere, moisture in the form of water vapor condenses as it comes into contact with a relatively low temperature atmosphere in the vents 63 of the cathode member 60. As a result, the condensed water is agglomerated in the vents 63 of the cathode member 60, thereby blocking the vents 63, and the air in the atmosphere passes through the vents 63 to the second of the MEA 10. It may not be smoothly supplied to the electrode layer 12.

Thus, in the direct oxidation fuel cell 100 according to the present embodiment, the electricity generating unit 90 is provided with an adsorption member 70 formed on the cathode member 60, and the adsorption member 70 is provided. The moisture generated in the second electrode layer 12 of the MEA 10 is absorbed and discharged to a predetermined collecting means.

In this embodiment, the adsorption member 70 is disposed in close contact with the exposed surface of the cathode member 60 exposed to the atmosphere, it is made in the form of a sheet corresponding to the size of the cathode member 60.

Specifically, the adsorption member 70 is in close contact with the exposed surface of the cathode member 60, that is, the surface opposite to the surface that is in close contact with the second electrode layer 12 of the MEA 10, the other side is atmospheric It is arranged to be exposed to the middle. At this time, the adsorption member 70 may be fixed by the fastening member mentioned above, it may be fixed by a predetermined case surrounding the electricity generating unit 90.

Here, the adsorption member 70 according to the present embodiment is made of micro-denire fibers having a plurality of pores, and the microfiber fibers are woven into fine microfibers having a predetermined denier thickness to absorb water. This excellent, fine yarn is made of a conventional microfiber fiber that can be woven tightly and has a large ground area for the exposed surface of the cathode member 60, and can easily discharge moisture by the myriad pores present in the fiber tissue. . At this time, the adsorption member 70 according to the present embodiment may be formed as a single-layer microfiber fibers, as shown in the figure, may be formed while forming two or more layers.

In this embodiment, the adsorption member 70 is arranged in close contact with the exposed surface of the cathode member 60, the plurality of holes 75 in communication with the vent holes 63 of the cathode member 60 To form. The plurality of holes 75 are for easily supplying air in the atmosphere to the second electrode layer 12 of the MEA 10 through the vents 63 of the cathode member 60.

Referring to the operation of the direct oxidation fuel cell 100 according to an embodiment of the present invention configured as described above in detail as follows.

First, fuel is distributed and supplied to the first electrode layer 11 of the MEA 10 while flowing along the flow path 42 of the anode member 40. Then, in the first electrode layer 11 of the MEA 10, hydrogen contained in the fuel is separated into electrons and hydrogen ions (protons) by an oxidation reaction of the fuel. At this time, hydrogen ions are transferred to the second electrode layer 12 through the membrane 13 of the MEA 10, and electrons do not pass through the membrane 13 and are transferred to the cathode member 60 through the anode member 40. Is moved.

Through this process, the direct oxidation fuel cell 100 according to the present embodiment generates a current due to the movement of the electrons, and the anode member 40 and the cathode member 60 collect different currents. The electric charges are configured as the current collector plates 41 and 61, so that electric energy having a predetermined potential difference can be output.

At the same time, the air in the air is supplied to the second electrode layer 12 of the MEA 10 through the vent holes 63 of the cathode member 60 by natural diffusion or convection. Then, in the second electrode layer 12 of the MEA 10, hydrogen ions moved through the membrane 13, electrons moved through the anode member 40, and vent holes 63 of the cathode member 60 are removed. Heat and moisture are generated by the reduction reaction of the air provided through.

In this process, moisture generated in the second electrode layer 12 of the MEA 10 is agglomerated in the vent holes 63 of the cathode member 60, and thus the adsorption member ( Since 70 is disposed in close contact with each other, the adsorption member 70 absorbs the moisture and discharges the moisture to the outside of the vents 63 through the plurality of pores. At this time, moisture absorbed by the adsorption member 70 and discharged to the outside of the vent holes 63 may be collected by a separate collecting means.

Therefore, in the direct oxidation type fuel cell 100 according to the present embodiment, the moisture aggregated in the vent holes 63 of the cathode member 60 is absorbed by the adsorption member 70, and thus the outside of the vent holes 63. Since it is discharged to, it is possible to prevent the closed end, such as clogging the vent holes 63 of the cathode member 60 by the moisture. As a result, air in the atmosphere may be smoothly supplied to the second electrode layer 12 of the MEA 10 through the vents 63 of the cathode member 60.

FIG. 3 is an exploded perspective view showing another exemplary embodiment of a direct oxidation fuel cell according to the present invention, and FIG. 4 is a cross sectional configuration diagram of FIG. 3.

Referring to the drawings, the direct oxidation type fuel cell 200 according to the present embodiment is based on the structure of the electric embodiment, and generates electricity in which the adsorption member 170 is interposed between the cathode member 160 and the MEA 110. Unit 190 may be configured.

Specifically, in the present embodiment, the adsorption member 170 has the same structure as in the previous embodiment, and one side between the cathode member 160 and the MEA 110 is the second electrode layer 112 of the MEA 110. ) Close to the other side of the surface of the cathode member 160 is exposed to the atmosphere.

Since the remaining configurations and functions of the direct oxidation fuel cell 200 and the electricity generation unit 190 according to the present embodiment are the same as those of the electric embodiment, detailed description thereof will be omitted.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

According to the direct oxidation type fuel cell according to the embodiment of the present invention as described above, as provided with an electricity generating unit including an adsorption member that can easily absorb and discharge the moisture aggregated in the vent holes of the cathode member. In addition, it is possible to prevent the closed end such that the vent holes of the cathode member are blocked by moisture. Therefore, since the air in the air can be smoothly supplied to the MEA through the vents of the cathode member, the performance efficiency and reliability of the entire fuel cell can be further improved.

Claims (9)

At least one electricity generating unit having an anode member and a cathode member disposed in close contact with the membrane-electrode assembly at the center thereof to generate electrical energy and moisture by reaction of fuel and oxygen. Including; The electricity generating unit, And an adsorption member formed on the cathode member to absorb and discharge the moisture, wherein the adsorption member is formed as microfiber fibers. According to claim 1, A direct oxidation fuel cell configured to expose the cathode member to the atmosphere. The method of claim 2, The adsorption member is a direct oxidation fuel cell disposed in close contact with the exposed surface of the cathode member. According to claim 1, And said adsorption member is interposed between said cathode member and said membrane-electrode assembly. According to claim 1, The adsorption member is a direct oxidation fuel cell consisting of a sheet having a plurality of pores. According to claim 1, And the cathode member includes a plurality of vents for circulating air to the membrane-electrode assembly. The method of claim 6, The adsorption member is a direct oxidation fuel cell comprising a plurality of holes in communication with the vent holes. According to claim 1, And the anode member includes a flow path for distributing the fuel, wherein the flow path has a meander shape. According to claim 1, And the anode member and the cathode member are configured as current collector plates for collecting current having different polarities.

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