KR20090073584A - Separator of fuel cell and fuel cell comprising same - Google Patents

Abstract

A separator is provided to improve efficiency of a fuel cell by exchanging materials in the fuel cell through increase in flux toward a membrane electrode assembly at a trench supplying fuel and oxidizer to the membrane electrode assembly of the fuel cell. A separator(110,120) for a fuel cell comprises a plate-like substrate(112); a trench(114) which is formed on one surface of the base material, and flows fluid supplied to fuel cell; and an obstacle(116) protruded from the bottom surface of the trench. The cross-sectional shape of the obstacle has a shape in which the predetermined profile is repeated in a main flow direction.

Description

 Separator for fuel cell and fuel cell comprising same {separator of fuel cell and fuel cell comprising same}

The present invention relates to a separator and a fuel cell including the same.

The types of fuel cells are molten carbonate fuel cells (MCFC) and solid oxide fuel cells (SOFC) operating at temperatures higher than 600 ° C and phosphoric acid operating at relatively low temperatures below 200 ° C. Phosphoric Acid Fuel Cells (PAFC) and Polymer Electrolyte Fuel Cells (PEFC).

In addition, unlike polymer electrolyte fuel cells, there are direct methanol fuel cells (DMFC) that use methanol as a fuel. Among them, the polymer electrolyte fuel cell can operate at a low temperature of 70 to 80 ° C., and can maintain a high current density. For this reason, the polymer electrolyte fuel cell has a fast starting capability, can be miniaturized, and can be made a light battery, which is suitable for application as a mobile power source.

In a fuel cell, an electrochemical reaction consists of two reactions: an oxidation reaction at an anode and a reduction reaction at a cathode. Two electrodes included in the unit cell of the fuel cell may be provided in the form of a membrane electrode assembly (MEA).

The separator, or separator, coupled to the membrane electrode assembly includes a flow path (chamber) capable of supplying fuel or an oxidant to each electrode of the membrane electrode assembly. The electrode exposed from one side of the flow path is supplied with fuel and oxidant supplied through the flow path.

On the other hand, when laminar flow is formed in the flow path, the value of the flow rate toward the electrode may be small. In this case, the efficiency of the fuel cell may be lowered due to inactive material exchange.

The present invention provides a separator and a fuel cell including the same.

According to one aspect of the invention, the plate-shaped base material; A trench formed on one surface of the base material, through which a fluid supplied to the fuel cell may flow; And there is provided a separator for a fuel cell comprising an opterle protruding from the bottom of the trench.

The cross-sectional shape of the optule may be a shape in which a predetermined profile is repeated in the main flow direction in which fluid flows in the trench. In addition, the cross-sectional shape profile of the opster can be airfoil, inverted airfoil or triangle.

On the other hand, the opsterle of the separator may have a width corresponding to the trench up to the height protruding from the bottom of the trench.

According to another aspect of the present invention, a separator comprising a plate-like base material, a trench formed on one surface of the base material and an obstacle protruding from the bottom of the trench, through which a fluid supplied to the fuel cell can flow. ; And a plate-shaped membrane electrode assembly (MEA) coupled with the separator to cover the trench.

The cross-sectional shape of the opsterle included in the fuel cell may be a shape in which a predetermined profile is repeated in the main flow direction in which fluid flows in the trench. In addition, the cross-sectional shape profile of the opster can be airfoil, inverted airfoil or triangle.

On the other hand, the opsterle of the separator included in the fuel cell may have a width corresponding to the trench up to the height protruding from the bottom of the trench.

Other aspects, features, and advantages other than those described above will become apparent from the following drawings, claims, and detailed description of the invention.

According to a preferred embodiment of the present invention, by providing a trench structure that can increase the flow velocity in the membrane electrode assembly direction in the trench formed in the separator, it is possible to improve the efficiency of the fuel cell.

Hereinafter, a separator for a fuel cell and a fuel cell including the same according to the present invention will be described in detail with reference to the accompanying drawings. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, in the description with reference to the accompanying drawings, the same or corresponding components will be given the same reference numerals and duplicate description thereof will be omitted.

1 is an exploded perspective view of a fuel cell according to an embodiment of the present invention. Referring to FIG. 1, the membrane electrode assembly 100, the ion exchange membrane 102, the first electrode 106, the second electrode 104, the first separator 110, the base material 112, the trench 114, An opsterle 116 and a second separator 120 are shown.

The membrane electrode assembly 100 includes an ion exchange membrane 102 and a first electrode 106 and a second electrode 104 coupled to the ion exchange membrane 102. The first electrode 106 and the second electrode 104 may be referred to as an anode or a cathode according to whether the reaction occurring there is an oxidation reaction or a reduction reaction.

In the fuel cell, the ion exchange membrane 102 may function as a passage through which hydrogen ions are exchanged. For example, in the case of a direct methanol battery, Nafion (registered trademark of Du Pont) membrane may be used.

The first electrode 106 and the second electrode 104 may be coupled to the membrane electrode assembly by a hot press process or the like. Although not shown in FIG. 1, a gas diffusion layer (GDL) may be additionally included outside the first electrode 106 and the second electrode 104. Meanwhile, in the present exemplary embodiment, the first electrode 106 and the second electrode 104 may have a symmetric trench structure.

As the base material 112, graphite or a composite carbonaceous material may be used. Graphite or composite carbon-based materials have the advantage of high corrosion resistance to redox reactions occurring in fuel cells. In this case, thermosetting and thermoplastic resins may be generally used to fill the micropores of the separator material to prevent the migration of hydrogen ions and to facilitate molding during molding.

On the other hand, the base material 112 may be made of a metal. In the case of the metal base material, the electrical conductivity is excellent, and the contact resistance can be minimized due to the excellent roughness characteristics. In addition, since the thickness of the separator can be reduced, the degree of integration of the fuel cell is improved.

The trench 114 is a passage formed on one surface of the base material 112. The fuel and the oxidant of the fuel cell may be supplied to the membrane electrode assembly 100 through the passage. In the present embodiment, the trench is formed in the form of a passage having a rectangular cross section.

Three surfaces constituting the cross section of the trench 114 are provided by the base material 112, and the other surface, that is, the ceiling surface, is covered by the membrane electrode assembly 100. The material movement constituting the chemical reaction of the fuel cell may be performed through the region covered by the membrane electrode assembly 100.

The trench 114 may be formed by a method of mechanically processing a metal base material. For example, a general sheet forming process may be used. In this case, it is possible to process the separator including the trench 114 and the opsterle 116 with a thin metal plate (eg, stainless steel) using a pre-made mold.

Meanwhile, in addition to the general thin plate forming process mentioned above, the trench 114 and the opster 116 may be formed using a sand blast process. In this process, the small particles can be shot with the base material to form the trenches 114 and the opsterles 116.

The opsterle 116 is a structure for changing the flow of the fluid in the flow path of the fuel cell. The opsterle 116 may be provided to protrude from the bottom of the trench 114. The opsterle 116 may disrupt the flow of fluid within the flow path.

The opsterle 116 may be formed by performing additional processing on the preformed trench 114, or may be formed together with the trench 114 using a trench forming process. It is also possible to attach the opsterle 116 to the wall surface of the trench 114.

When the flow path of the fuel cell is formed in a shape having a certain cross section, the fluid in the flow path may form a laminar flow. In this case, compared to the main flow direction velocity component of the fluid, the direction of the membrane electrode assembly 100 which is a mass exchange place, that is, the ceiling surface direction velocity component of the trench 114 becomes relatively small.

The present embodiment is characterized by increasing the velocity component in the direction of the membrane electrode assembly 100 of the fluid in the flow path by installing the opsicle 116 in the flow path so that material exchange can be more actively performed.

The change in the shape of the optule 116 and the flow rate caused by the optule 116 will be described in detail with reference to the other drawings.

On the other hand, in addition to the components described above, various components may be used to form the unit cell of the fuel cell. For example, a gasket may be disposed between the separator (separator) and the membrane electrode assembly 100 to prevent leakage of fluid transferred through the flow path. Since other configurations of the fuel cell are not the main features of the present invention, further description thereof will be omitted.

2 is a partially enlarged view of a separator included in the fuel cell illustrated in FIG. 1, and FIGS. 3 and 4 are cross-sectional views of the separator illustrated in FIG. 2. 2 to 4, a first separator 110, a base material 112, a trench 114, and an optericle 116 are illustrated.

Laminar flow may be formed in a section without the opsterle 116, in which case the main flow direction of the fluid is in the longitudinal direction of the flow path. In this embodiment the main flow direction is indicated by the x-axis, which in turn is the longitudinal direction of the trench 114. On the other hand, the y-axis direction is the width direction of the trench 114, the z-axis direction indicates the ceiling surface direction of the trench 114, that is, the membrane electrode assembly 100 direction.

3 is a cross-sectional view taken along the line AA ′ of FIG. 2. This shows the main flow direction cross-sectional shape of the opsterle 116. In this embodiment, the cross-sectional shape of the opsterle 116 has a shape in which the profile of the airfoil is repeated in the main flow direction in which the fluid flows in the trench 114.

In this embodiment, the opsterle 116 has a profile of an airfoil that is repeated nine times, and the repeated profiles are continuous with no intermediate intervals. The opsicle 116 having this cross-sectional shape generates turbulence in the flow path to form a flow having a larger membrane electrode direction velocity component than in the case of laminar flow.

The number of repetitions of the profile or the spacing between each repeated profile may be changed as necessary, and consideration may be given to the structure of the separator and the length of the trench 114 and the pressure applied to flow the fluid.

4 is a cross-sectional view taken along the line B-B 'shown in FIG. This shows the trench 114 widthwise cross-sectional shape of the opsterle 116.

In this embodiment, the opsterle 116 has a width corresponding to the trench 114 up to a height protruding from the bottom of the trench 114. In this case, the opsterle 116 has a shape of a flow blocker which obstructs the flow, and the change in the velocity of the flow can be made larger by blocking the flow below the protrusion height of the opsterle 116 more efficiently. have.

5 is a partially enlarged view of a separator according to an embodiment of the present invention. Referring to FIG. 5, a base material 112, a trench 114, and an opterle 150 are illustrated.

In the present embodiment, the profile constituting the main flow direction (x-axis direction) cross-sectional shape of the opticle 150 is an inverse airfoil.

As mentioned above, the number of repetitions and the repetition interval of the profile may be changed as necessary. In addition, in the present embodiment, the opsterle 150 has a width corresponding to the trench 114 up to a height protruding from the bottom of the trench 114.

6 is a partially enlarged view of a separator according to an embodiment of the present invention. Referring to FIG. 6, a base material 112, a trench 114, and an opsterle 160 are illustrated.

In the present embodiment, the profile constituting the main flow direction (x-axis direction) cross-sectional shape of the opticle 160 is triangular.

As mentioned above, the number of repetitions and the repetition interval of the profile may be changed as necessary. In addition, in the present embodiment, the opsterle 160 has a width corresponding to the trench 114 up to a height protruding from the bottom of the trench 114.

7 to 9 are simulation results of the fluid flow of the separator illustrated in FIG. 2.

FIG. 7 is a simulation result of the x-axis speed change in the separator of FIG. 2, FIG. 8 is a simulation result of the y-axis speed change in the separator of FIG. 2, and FIG. 9 is a z-axis in the separator of FIG. 2. This is the result of simulation of the change of direction velocity.

Referring to this, it can be observed that the presence of the opsterle generates a flow with various velocity components in the flow path. In particular, referring to FIG. 9, an increase in the velocity component in the direction of the membrane electrode assembly 100 is observed.

In this way, by installing the opsicle 116 protruding from the bottom of the trench 114 to face the membrane electrode assembly 100, the flow velocity in the z-axis direction can be increased more efficiently.

The present embodiment thus increases the membrane electrode direction speed so that material exchange at the electrodes of the fuel cell can be more actively performed.

10 is a result of simulating the fluid flow of the separator illustrated in FIG. 5, and FIG. 11 is a result of simulating the fluid flow of the separator illustrated in FIG. 6.

Referring to Figures 10 and 11, it can be seen that the presence of the opsterle in the flow path causes a change in the speed of flow.

In the present embodiment, it is determined that various velocity components are observed as compared with the trench having no opscrew, which can also play a role of improving the efficiency of the fuel cell by actively exchanging materials in the fuel cell. .

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

So far I looked at the center of the present invention with respect to the embodiment. Many embodiments other than the above-described embodiments are within the scope of the claims of the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

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

FIG. 2 is a partially enlarged view of a separator included in the fuel cell illustrated in FIG. 1.

3 and 4 are cross-sectional views of the separator illustrated in FIG. 2.

5 is a partially enlarged view of a separator according to an embodiment of the present invention.

6 is a partially enlarged view of a separator according to an embodiment of the present invention.

7 to 9 are simulation results of the fluid flow of the separator illustrated in FIG. 2.

FIG. 10 is a simulation result of fluid flow of the separator illustrated in FIG. 5.

FIG. 11 is a simulation result of the fluid flow of the separator illustrated in FIG. 6.

<Description of the symbols for the main parts of the drawings>

100 membrane electrode assembly 102 ion exchange membrane

104: second electrode 106: first electrode

110: first separator 112: base material

114: trench 116: obstacle

120: second separator

Claims (12)

Plate-like base material; A trench formed on one surface of the base material and capable of flowing a fluid supplied to a fuel cell; And A separator for a fuel cell comprising an obstacle protruding from the bottom of the trench. The method of claim 1, The cross-sectional shape of the opsterle is And a profile repeating a predetermined profile in a main flow direction in which the fluid flows in the trench. The method of claim 2, The profile is a fuel cell separator, characterized in that the airfoil (airfoil). The method of claim 2, The profile is a fuel cell separator, characterized in that the inverse airfoil (inverse airfoil). The method of claim 2, The profile is a fuel cell separator, characterized in that the triangle. The method according to any one of claims 1 to 5, The opsterle is And a width corresponding to the trench from the bottom of the trench to a height protruding from the bottom of the trench. A separator formed on a plate-like base material and one surface of the base material, the separator including a trench and an obstacle protruding from the bottom of the trench, through which a fluid supplied to a fuel cell can flow; And And a plate-shaped membrane electrode assembly (MEA) coupled with the separator to cover the trench. The method of claim 7, wherein The cross-sectional shape of the opsterle is And a predetermined profile is repeated in the main flow direction in which the fluid flows in the trench. The method of claim 8, And said profile is an airfoil. The method of claim 8, And said profile is an inverse airfoil. The method of claim 8, The profile is a fuel cell, characterized in that the triangle. The method according to any one of claims 7 to 11, The opsterle is And a width corresponding to the trench, up to a height protruding from the bottom of the trench.

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