KR20090016336A - Welding apparatus for welding metal separator of fuel cell - Google Patents

Abstract

A welding apparatus for welding a metal separator in a fuel cell is provided to spot-weld a metal separator through plural welding points of an upper plate and a lower plate of the metal separator, thereby reducing a manufacturing time and improving productivity. A welding apparatus(100) for welding a metal separator in a fuel cell comprises the following units. A molding base(10) combined with a lower plate has a placing face(11). A vacuum cup(40) holds an upper plate in a vacuum and matches the upper plate to a lower plate. An electrode holder(30) has a plurality of welding electrodes(21) installed near each edge of the molding base. An current applying unit(50), which is mounted in a robot arm and fixed on a surface of the electrode holder, applies active current to a welding electrode.

Description

Welding device for joining fuel cell metal separator plate {WELDING APPARATUS FOR WELDING METAL SEPARATOR OF FUEL CELL}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding device, and more particularly, to a welding device for joining a metal separator plate of a fuel cell, which enables spot welding of a top plate and a bottom plate of a metal material to produce a separator plate of a fuel cell.

In general, a fuel cell is a power generation system that directly generates electricity by an electrochemical reaction between hydrogen and oxygen, and has a characteristic of continuously generating power by receiving a chemical reactant from the outside without a separate charging process.

The basic structure of a fuel cell has a structure in which a membrane-electrode assembly (MEA) composed of an electrode, a catalyst layer, and a thin film layer, and a separator (commonly referred to in the art as a "bipolar plate") are alternately stacked.

The separator serves to supply hydrogen gas, which is fuel, and air, which is an oxidant gas, to the membrane-electrode assembly, to collect current, and to prevent risks such as explosion and combustion due to direct contact between hydrogen and oxygen. Therefore, gas permeability must be low and electrical conductivity must be good.

The fuel cell separator is formed as a graphite or carbon composite, and has a thickness of at least 0.4 mm to 0.6 mm to prevent gas or liquid permeation. However, such a separator has a disadvantage that the thickness is thick, the molding is complicated, and the price is expensive.

Recently, in order to solve such a problem, a number of separator plates made of metal are used. This separator has the advantage of being thinner than the separator made of graphite or carbon composite material.

In this case, as shown in FIG. 1, the separator 9 is disposed on both sides of the membrane-electrode assembly 3 as a center, and the upper plate 1 and the lower plate 2 of the metal material are bonded to each other. Consists of a structure.

The separator 9 is formed by pressing the upper plate 1 and the lower plate 2, which are bent as unevenness by press molding, and are bonded to each other, for supplying hydrogen gas to the membrane-electrode assembly 3 on one side thereof. Forming a hydrogen gas channel (4), forming an oxidant gas channel (5) for supplying an oxidant gas to the membrane-electrode assembly (3) on the other side, and cooling medium between the upper plate (1) and the lower plate (2) The cooling medium flow passage 6 which can distribute | circulates is formed.

In the separator 9 of the fuel cell according to the related art, the edges of the upper plate 1 and the lower plate 2 are bonded to each other by a sealing agent 8 made of a silicone rubber material, and the sealing agent 8 Is applied to the upper plate 1 or the lower plate 2, and the upper plate 1 and the lower plate 2 are transported and manufactured.

However, in the related art, since the coating work of the sealant 8 and the conveyance and bonding work of the upper and lower plates 1 and 2 are all performed by hand, the production labor and manufacturing time are long, and the productivity is low. The airtightness of 1) and the lower plate 2 is weak, and it has the disadvantage that it is disadvantageous in mass production and mass production.

Therefore, the present invention was created in order to improve the problems as described above, by bonding the upper plate and the lower plate of the fuel cell separator plate made of a metal material by spot welding so as to realize the automation of the separator production and mass production of the separator plate. It is an object of the present invention to provide a welding device for joining a metal separator plate of a fuel cell.

In the welding device for joining a metal separator plate of a fuel cell according to an exemplary embodiment of the present invention for achieving the above object, a membrane-electrode assembly is formed by bonding a top and bottom plates of a metal material bent as unevenness to each other. Forming channels of hydrogen gas and oxidant gas respectively corresponding to both sides of the MEA, and forming a flow passage of the cooling medium along the longitudinal direction of the channel between the upper plate and the lower plate, the combination of the lower plate and the form A mold base having a seating surface formed on the upper surface thereof, and a vacuum cup for vacuum suctioning the upper plate and matching the upper plate to the upper surface of the lower plate are mounted on the lower surface of the mold base and corresponding to both edge portions of the mold base. An electrode holder to which welding electrodes are installed, and mounted to the robot arm and fixed to an upper surface of the electrode holder, And a current applying unit for applying an effective current to the contact electrode.

In the welding device for joining the metal separator plate of the fuel cell, the current applying unit is installed inside the outer case with a cylindrical outer case fixed to the robot arm, the upper end is open and the lower end is closed. An inner case, a plurality of brushes disposed radially on an inner circumferential surface of the inner case corresponding to the welding electrodes, and a rotor rotatably installed at a central portion of the inner case to electrically connect the welding electrode and the brush. And a stepping motor connected by the rotor and the drive shaft to rotate the rotor at a predetermined angle.

In the welding apparatus for joining the metal separator plate of the fuel cell, the rotor is formed to protrude on one side of the central portion corresponding to the one side brush when the rotor is referred to the center portion so as to contact each of the pair of brushes facing each other symmetrically. It is preferable that the first contact portion to be formed, and the second contact portion protruding to the other side of the central portion corresponding to the other one side brush.

The welding device for joining the metal separator plate of the fuel cell may be electrically connected to each of the brushes and the welding electrode by an electric wire cable passing through the inner case.

In the welding device for joining the metal separator plate of the fuel cell, the rotor may be connected with a (+) electrode, and the mold base may be connected with a (-) electrode. In this case, it is preferable that the welding electrode and the mold base form a closed circuit by the rotor.

In the welding device for joining the metal separator plate of the fuel cell, the electrode holder is formed in the form of a hollow plate, the electrode holder is provided with a connecting rod connected to the vacuum cup to move up and down, the connecting rod An elastic member may be installed at the center and between the electrode holder and the vacuum cup.

In the welding device for joining the metal separator plate of the fuel cell, the mold base may include a plurality of cooling water flow paths for dissipating heat generated during welding of the upper and lower plates along the direction of the channel.

According to the welding device for joining a metal separator plate of a fuel cell according to an exemplary embodiment of the present invention as described above, the upper plate and the bottom plate of the separator plate made of a metal material are used as a plurality of welding points by a plurality of welding electrodes. Since spot welding can be performed, the production maneuver and manufacturing time of the separator can be reduced, productivity can be improved, space can be secured, and the mass production of the separator can be performed.

In addition, according to the present embodiment, since the upper plate and the lower plate can be bonded in a balanced manner by a plurality of welding electrodes, deformation of the separating plate can be prevented, and since the upper plate and the lower plate can be spot welded using a welding robot, automation is possible. The process is possible, and as a single device it is possible to carry out the operation of transporting the upper and lower plates and separation plates, there is an effect that can simplify the installation.

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

2 is a partially cutaway perspective view illustrating a welding device for joining a metal separator plate of a fuel cell according to an exemplary embodiment of the present invention, FIG. 3 is a front sectional configuration diagram of FIG. 2, and FIG. 4 is IV- of FIG. 2. It is a planar cross-sectional view along line IV.

Referring to the drawings, the welding device 100 for joining a metal separator plate of a fuel cell according to an embodiment of the present invention is separated for fuel cells disposed on both sides of the membrane-electrode assembly 3 as shown in FIG. 1. Applied to make a plate.

Here, the separator supplies hydrogen gas to one side (anode electrode) of the membrane-electrode assembly 3 and an oxidant gas such as air to the other side (cathode electrode) of the membrane-electrode assembly 3. In addition, the heat generated during the electrochemical reaction of hydrogen gas and oxidant gas is cooled, and the anode electrode and the cathode electrode are electrically connected.

The welding device 100 is a spot-welded method of joining a top plate (1: see FIG. 1) and a bottom plate (2: see FIG. 1) of a metal material bent as irregularities to form a membrane-electrode on one side. Hydrogen gas channel (4: see FIG. 1 below) for supplying hydrogen gas to the anode electrode of the assembly 3 (see FIG. 1 hereinafter), supplying oxidant gas to the cathode electrode of the membrane-electrode assembly 3 on the other side To form an oxidant gas channel 5 (see FIG. 1 hereinafter) and to form a cooling medium flow passage 6 (see FIG. 1 hereinafter) capable of circulating the cooling medium between the top plate 1 and the bottom plate 2. will be.

In the present embodiment, the configuration of the welding device 100 for joining the metal separator plate of the fuel cell is basically a mold base 10, an electrode holder 30 is provided with a plurality of welding electrodes 21, electrode holder It consists of a current application unit 50 for applying a current to (30).

The mold base 10 is provided as a metal plate having a predetermined thickness, and a seating surface 11 forming a coupling with the lower plate 2 is formed on an upper surface thereof. That is, grooves 11a having a shape corresponding to the uneven portion of the lower plate 2 are horizontally formed on the upper surface of the mold base 10, and the ribs 11b are formed to protrude between the grooves 11a. .

In the mold base 10, a plurality of coolant flow paths 13 through which a coolant flows through the body to release heat generated during welding of the upper plate 1 and the lower plate 2 are formed. The flow path 13 is formed long along the longitudinal direction of the rib 11b.

The electrode holder 30 is for supporting the plurality of welding electrodes 21 and the current applying unit 50, and is made in the form of a hollow plate, the lower surface of the plurality of welding electrodes 21 is installed On the upper surface, the current applying unit 50 is mounted.

The welding electrodes 21 are disposed to be spaced apart at regular intervals from both edge portions of the lower surface of the electrode holder 30 corresponding to both edge portions corresponding to the longitudinal direction of the rib 11b of the mold base 10.

In addition, the lower surface of the electrode holder 30 has a conventional structure for vacuum suction of the upper plate 1 and matching the upper plate 1 to the upper surface of the lower plate 2 seated on the mold base 10. The vacuum cup 40 is installed.

The vacuum cup 40 is for vacuum-suctioning the upper plate 1 stacked in a predetermined pallet and pressing the upper plate 1 and the lower plate 2 matched with each other on the mold base 10, and the electrode holder 30. It is connected with the connecting rod 41 installed to be movable in the vertical direction with respect to.

In this case, one end of the connection rod 41 is supported on the inner bottom surface of the electrode holder 30, and the vacuum cup 40 is installed at the other end.

And between the electrode holder 30 and the vacuum cup 40 is provided with an elastic member 43 for buffering the pressure of the electrode holder 30, this elastic member 43 is made of a compression spring, the connecting rod ( 41) is fitted.

In the present embodiment, the current applying unit 50 is for applying the effective current to the welding electrode 21, the outer case 51, the inner case 53, the brush 55, the rotor 57 and It is made as a stepping motor 59.

The outer case 51 is mounted to the arm 60 of the welding robot, is fixedly installed on the upper surface of the electrode holder 30, the upper case and the lower end is made of a cylindrical case closed.

The inner case 53 is a cylindrical case corresponding to the shape of the outer case 51 and has a structure in which an upper end is opened and a lower end is closed, and is formed as a non-conductor.

The brush 55 is made of a conductor and is disposed to be radially spaced apart from the inner circumferential surface of the inner case 53 in the circumferential direction by a number corresponding to the welding electrodes 21.

In this case, each of the brushes 55 and the corresponding welding electrodes 21 are electrically connected by an electric wire cable 56 passing through the inner case 53.

The rotor 57 is a rotor rotatably installed in the inner case 53, and sequentially contacts the brushes 55 and rotates the welding electrodes 21 and brushes corresponding to the rotors 55. It will function to electrically connect the 55.

The rotor 57 is configured to be in contact with a pair of brushes 55 which are symmetrically opposed to each other while rotating by a predetermined angle in one direction.

Preferably, the rotor 57 has a first contact portion 57a which is formed to protrude on one side of the center portion corresponding to one side brush 55 which is symmetrically opposed to each other when referring to the center portion, and the other side brush 55. The second contact portion (57b) is formed to protrude on the other side of the central portion corresponding to the.

Here, the rotor 57 is formed as a conductor connected to the positive electrode of the power source, and the negative electrode of the power source is connected to the mold base 10.

That is, when the rotor 57 rotates and the first and second contact portions 57a and 57b respectively contact the brushes 55 corresponding thereto, the respective brushes 55 and the respective welding electrodes 21 corresponding thereto are provided. Since the electric wire cable 56 is electrically connected, the welding electrode 21 and the mold base 10 form a closed circuit.

The stepping motor 59 is installed inside the outer case 51, and the driving shaft 59a is connected to the center of the rotor 57 to rotate the rotor 57 at a predetermined angle.

According to the operation of the welding device 100 for joining the metal separator plate of the fuel cell according to the exemplary embodiment of the present invention configured as described above, as shown in Figure 5a, the mounting surface 11 of the mold base 10 In the state in which the lower plate 2 is loaded, the upper plate 1 is vacuum-adsorbed as the vacuum cup 40 as shown in FIG. 5B, and the upper plate 1 is matched to the upper surface of the lower plate 2.

In this case, a sealant (not shown) such as a silicone rubber is applied to the edges of the upper plate 1 and the lower plate 2 for the purpose of reinforcing the airtightness of the upper plate 1 and the lower plate 2 as the pretreatment operation. You can also go through the process.

Subsequently, when the electrode holder 30 is pressed toward the mold base 10, the electrode holder 30 moves toward the mold base 10 while overcoming the elastic force of the elastic member 43, thereby welding electrodes. 21 presses both edge portions of the upper plate 1.

At this time, the first and second contact portions 57a and 57b of the rotor 57 are in contact with a pair of brushes 55 that face each other symmetrically.

When the power is applied to the rotor 57 in such a state, each brush 55 and the corresponding welding electrode 21 which are in contact with the first and second contact portions 57a and 57b of the rotor 57 are provided. Since the electric wire cable 56 is electrically connected, the welding electrode 21 and the mold base 10 form a closed circuit.

Therefore, one side of the upper plate 1 which contacts the welding electrode 21 by heat generated as electrical contact resistance due to the closed circuit of the welding electrode 21 and the mold base 10, and the lower plate 2 corresponding thereto. One side of can be melt-bonded.

At the same time, the stepping motor 59 is operated to rotate the rotor 57 by a predetermined angle. Then, as described above, the first and second contact portions 57a and 57b of the rotor 57 come into contact with the other brushes 55 so that the welding electrode 21 and the mold base 10 corresponding to the brushes 55 are formed. ), The welding electrode 21 performs spot welding sequentially.

Meanwhile, in the present embodiment, heat is generated in the welding electrodes 21 when welding the upper plate 1 and the lower plate 1 as described above, and the cooling water is transferred to the cooling water flow paths 13 of the mold base 10. By supplying the cooling water, the welding electrodes 21 and the upper and lower plates 1 and 2 may be cooled.

Thus, this embodiment spot welds the edge portions of the upper plate 1 and the lower plate 2 through the process as described above, so that the hydrogen gas channel 4, the oxidant gas channel 5 and the oxidant gas channel 5 as shown in FIG. It becomes possible to manufacture the separator plate 90 which forms the cooling medium flow path 6.

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.

Since these drawings are for reference in describing exemplary embodiments of the present invention, the technical idea of the present invention should not be construed as being limited to the accompanying drawings.

1 is a perspective view schematically illustrating a general fuel cell to which a metal separator is applied.

2 is a partially cutaway perspective view illustrating a welding device for joining a metal separator plate of a fuel cell according to an exemplary embodiment of the present invention.

3 is a front sectional configuration diagram of FIG. 2.

4 is a cross-sectional view taken along line IV-IV of FIG. 2.

5A and 5B are views for explaining the operation of a welding device for joining a metal separator plate of a fuel cell according to an exemplary embodiment of the present invention.

6 is a perspective view schematically illustrating a metal separator manufactured by a welding device for joining a metal separator of a fuel cell according to an exemplary embodiment of the present invention.

Claims (9)

The upper and lower plates of the metal material bent as irregularities are bonded to each other to form channels of hydrogen gas and oxidant gas respectively corresponding to both sides of the membrane-electrode assembly (MEA), and the length of the channel between the upper plate and the lower plate. A welding device for joining a metal separator plate of a fuel cell, which forms a flow passage of a cooling medium along a direction, A mold base on which a seating surface forming a coupling with the lower plate is formed on an upper surface thereof; An electrode holder on which a vacuum cup for vacuum suctioning the upper plate and matching the upper plate to the upper surface of the lower plate is mounted on a lower surface thereof, and a plurality of welding electrodes are installed corresponding to both edges of the mold base; And A current applying unit mounted on the robot arm and fixed to an upper surface of the electrode holder to apply an effective current to the welding electrode Welding device for joining a metal separator plate of a fuel cell comprising a. According to claim 1, The current application unit, A cylindrical outer case fixed to the robot arm, an inner case installed inside the outer case with an upper end opened and a lower end closed, and radially disposed on an inner circumferential surface of the inner case corresponding to the welding electrodes A plurality of brushes, a rotor rotatably installed at a central portion of the inner case, and a rotor for electrically connecting the welding electrode and the brush, and a stepping to rotate the rotor at a predetermined angle connected by the rotor and a drive shaft. Welding device for joining a metal separator plate of a fuel cell comprising a motor. The method of claim 2, The rotor has a first contact portion protruding on one side of the center portion corresponding to the one side brush, and corresponding to the other side brush when the center portion is referred to each contact with the pair of brushes symmetrically facing each other. A welding device for joining metal separators in a fuel cell, comprising a second contact portion protruding from the other side of the center portion. The method of claim 2, Welding device for joining a metal separator plate of a fuel cell in which each brush and the welding electrode are electrically connected by an electric wire cable passing through the inner case. The method of claim 4, wherein The rotor is connected to the (+) electrode, the mold base is connected to the welding electrode for a metal separator plate of the fuel cell. The method of claim 5, A welding device for joining a metal separator of a fuel cell in which the welding electrode and the mold base form a closed circuit by the rotor. The method of claim 2, A welding device for joining a metal separator of a fuel cell, wherein the inner case is made of a non-conductor, and the brush and the rotor are conductors. According to claim 1, The electrode holder is formed in the form of a hollow plate, the electrode holder is connected to the connecting rod is connected to the vacuum cup to move up and down, the elastic member between the electrode holder and the vacuum cup with the connection rod in the center Welding device for joining a metal separator plate of a fuel cell is installed. According to claim 1, And the mold base has a plurality of cooling water flow paths for dissipating heat generated during welding of the upper and lower plates along the direction of the channel.

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