KR20030003560A - End plate for fuel cell stack - Google Patents

Abstract

PURPOSE: Provided are end plates of a fuel cell stack unified with current collecting plates as one body, which can solve the corrosion problem of the end plates and the current collecting plates and minimize the number of parts and the size. CONSTITUTION: The end plates(12,14) of the fuel cell stack are produced by injection molding by using non-conductive plastics and the current collecting plates(22) are inserted in the end plates(12,14), wherein the current collecting plates(22) are not exposed to cooling water, fuel gas, and air supply port(42) and exhaust port(44) but the insides of the current collecting plates(22) are exposed for the contact with unit cells(21). The outside terminals(50) of the current collecting plates(22) are unified with the end plates(12,14).

Description

End plate for fuel cell stack

The present invention relates to an end plate of a fuel cell stack integrated with a current collector plate, and more particularly, to a manufacturing method of injection molding using a non-conductive material, and to supplying coolant, fuel gas, and air to an inner surface thereof. The current collector plate disposed so as not to be exposed to the port and the discharge port is inserted while exposing only the inner surface of the unit cell to be in contact with the unit cell. It is about.

In general, a fuel cell stack 1 includes an end plate 10 disposed at both ends, and an end plate 12, as shown in FIGS. 2A and 2B. And a fastening structure 30 for maintaining the airtightness and pressing force of the fuel cell assembly 20.

First, the fuel cell assembly 20 is separated from a current plate 22 and an electrode film 24 for sending electricity generated from the fuel cell stack 1 to an external load (not shown). The unit cell 21 is composed of a plate 25, a gas diffusion layer 26 and the like.

The fuel cell assembly 20 has a structure in which the unit cells 21 for generating electricity are stacked, and an external terminal 23 for sending electricity generated from the unit cells 21 to an external load is collected. It is provided in the front plate 22.

Next, the fastening structure 30 is a fastening bar (32, not shown in Figure 2b) of the electrode film 24 of the unit cell 21, the separator 25 and the gas diffusion layer 26 of the good Proper pressure is applied to the end plates 12, 14 to maintain electrical contact.

The end plates 12 and 14 are disposed at both ends when the fuel cell stack 1 is configured, and cooling water, fuel gas, and air may be supplied to the fuel cell cell assembly 20 to the first end plate 12 on one side. Each of the supply ports 42, discharge ports 44 for discharging cooling water, fuel gas, and air, and fastening grooves 16 for inserting and fastening the fastening bar 32, The second end plate 14 on the other side is a counterpart of the first end plate 12 that can be fastened to the fuel cell assembly 20 and pressurized constantly.

In particular, coolant, humidified fuel gas and air for cooling the fuel cell assembly 20 are supplied to the fuel cell assembly 20 through the corresponding port 42 of the first end plate 12. Cooling water, fuel gas, and air supplied to the battery cell assembly 20 are again discharged through the corresponding port 44 of the first end plate 12.

Therefore, each port 42, 44 of the first end plate 12 for supplying or discharging coolant, fuel gas, and air is connected to an external supply means (not shown) and an exhaust system (not shown). A fitting 46 is provided.

In order to fix the fittings 42 to the corresponding ports 42 and 44, fasteners 47 are coupled to the fittings 42, and each fastener 47 is connected to the corresponding ports 42, 44. The screw 48 is fastened at 44).

In addition, an O-ring 45 is provided for hermetic sealing of the fitting part 42.

In the conventional fuel cell stack (1) made as described above, the end plate (12, 14) is a rigidity that can give a uniform pressing force to the cell assembly 20, the influence of humidified fuel gas, air, coolant Should not have corrosion resistance, etc.

In addition, electrical insulation is required between the end plates 12 and 14 and the current collector plate 22.

Accordingly, the end plates 12 and 14 are made of graphite, or are coated with a light metal such as aluminum, and the end plates 12 and 14 and the current collector plate are secured to ensure electrical insulation. A separate insulating tape 28 may be interposed between the 22.

In addition, the current collector plate 22 is required to have good electrical conductivity and acid resistance, and is manufactured by surface-coating gold or TiN on aluminum, stainless steel, brass, or copper.

However, in the conventional fuel cell stack 1, as shown in FIG. 2A, cooling water, humidified fuel gas, and air supplied or discharged through the respective ports 42 and 44 are discharged to the first end plate. 12 is to pass through the current collector plate 22 in contact with the corrosion occurs in the pin hole and the like present in the coating layer.

When such corrosion occurs, a problem arises in that the metal ions generated by the corrosion contaminate the electrolyte membrane constituting the electrode membrane 24, thereby degrading its performance and durability.

In addition, corrosion may occur at the interface between the end plates 12 and 14 and the current collector plate 22, and if the airtightness problem caused by the corrosion product is caused, durability may be degraded and safety problems may occur due to the airtight destruction of hydrogen and air. Done.

In addition, when the insulating tape 28 is interposed at the interface for electrical insulation between the end plates 12 and 14 and the current collector plate 22, the insulating tape 28 is formed by the humidified fuel gas and air. 12, 14 or the current collector plate 22 may cause airtightness and durability problems.

In addition, even when the end plates 12 and 14 are coated, corrosion occurs in long-term use when pinholes exist, causing durability problems.

In addition, the first end plate 12 has to be threaded 48 to fix the fasteners 47, and the thickness of the first end plate 12 must be made thick due to the depth required for threading. As a screwing structure is used during fitting, a problem arises that the screw is released by vibration.

In addition, since the external terminal 23 of the current collector plate 22 should be exposed to the outside of the end plates 12 and 14, there is a problem that the size of the current collector plate 22 is increased.

Therefore, the present invention has been invented to solve the above problems, and can solve the problem of corrosion of the end plate and the current collector plate, and to provide an end plate of the fuel cell stack capable of reducing the number of parts and size reduction have.

1A and 1B are a cross-sectional view and a plan view, respectively, of a fuel cell stack equipped with an end plate of the present invention;

2A and 2B are a cross-sectional view and a plan view, respectively, of a fuel cell stack equipped with a conventional end plate and a current collector plate;

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

1 fuel cell stack 12 first end plate

14: second end plate 16: fastening groove

20 fuel cell assembly 21 unit cell

22 current collector plate 24 electrode film

25 separation plate 26 gas diffusion layer

28: insulating tape 30: fastening structure

42: supply port 44: discharge port

46: fitting portion 48: reinforcing material

48a: Uneven surface 50: External terminal

52: external terminal mounting portion 54: electrically conductive means

56: adapter 58: washer

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

The present invention for achieving the above object is made by a method of manufacturing injection molding using a non-conductive material, the inner surface of the supply port 42 and the discharge port 44 of the cooling water, fuel gas and air The current collector plate 22 disposed not to be exposed is inserted with only the inner surface of the unit cell 21 contacted, and the external terminal 50 of the current collector plate 22 for insertion of external load is inserted and installed. It is characterized in that the portion 52 is integrally molded.

In the preferred embodiment of the present invention, the external terminal 50 is exposed on the outer surface of the end plate (12, 14) so that one end can be connected to the external load and the other end is screwed structure to the current collector plate 22 An electrically conductive means (54) to be fastened, an adapter (56) inserted into the mounting portion (52) and connected to the current collector plate (22) separately from the electrically conductive means (54), and the electrically conductive means (54); It characterized in that it comprises a washer 58 for connecting the adapter 56.

In addition, in the preferred embodiment of the present invention, each of the ports 42 and 44 is characterized in that the fitting portion 46 for external connection is integrally molded.

In particular, the reinforcing material 49 is inserted through each of the ports 42 and 44 and the fitting portion 46.

In particular, the reinforcing material 49 is characterized in that its surface is an uneven surface.

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

1A and 1B are cross-sectional views and plan views, respectively, of a fuel cell stack on which an end plate of the present invention is mounted.

Here, reference numeral 16 denotes a fastening groove into which the fastening bar 32 (not shown in FIG. 2B) is inserted.

The present invention relates to an end plate in which end plates 12 and 14 disposed at both ends of a fuel cell stack 1 and a current collector plate 22 disposed inside two end plates 12 and 14 are integrated.

First, as illustrated in FIG. 1A, each current collector plate 22 is inserted into and integrated with the inner surfaces of the end plates 12 and 14 which are brought into contact with the current collector plates 22.

To this end, the end plates 12 and 14 are manufactured by injection molding of plastic.

In this case, the end plates 12 and 14 are formed to surround only the remaining surfaces except for this, exposing only the inner surface of the current collector plate 22 to which the unit cells 21 are in contact.

The end plates 12 and 14 may be made of plastic that can be injection molded and have no electrical conductivity, but may be made of waste-based plastic, and any plastic may be used as long as it has sufficient acid resistance and hydrogen resistance.

As described above, by manufacturing the end plates 12 and 14 by injection molding using plastic as a material, the weight can be reduced and a shape which is difficult to obtain in machining can be obtained.

In addition, by inserting the electrically conductive collector plates 22 into the electrically insulative plastic end plates 12 and 14, it is possible to manufacture an end plate which also serves as a collector plate function.

Here, the portion of the fuel cell assembly 20 that generates electricity is the electrode film 24 and transfers electricity through the gas diffusion layer 26, the size of the current collector plate 22 is the size of the gas diffusion layer 26 Suffice.

Therefore, in contrast to the size of the current collector plate manufactured in the same way as the size of the end plate, the size of the current collector plate 22 to be inserted into the end plates 12, 14 of the present invention is the requirement of the current collector plate 22 described above. The size of the cooling water, fuel gas and air can be placed inside the flow path of the cooling water, fuel gas and air so as not to pass through while satisfying the size characteristics.

That is, the current collector plate 22 is prevented from being exposed to the supply port 42 and the discharge port 44 of the cooling water, the fuel gas and the air, thereby preventing corrosion.

In addition, in the end plates 12 and 14 according to the present invention, the external terminal 50 of each current collector plate 22 is integrated with the end plates 12 and 14.

That is, as an embodiment of the external terminal 50, the mounting portions 52 are integrally formed on the end plates 12 and 14, and one end of the mounting portions 52 is formed on the end plates 12 and 14, respectively. An electroconductive means 54, such as a bolt, which is exposed on the outer surface and can be connected to an external load (not shown) is inserted.

In addition, the adapter 56, which is inserted into the installation unit 52 and connected to the current collector plate 22, separately from the electroconductive means 54, the electroconductive means 54 and the adapter 56 A connecting washer 58 is installed.

In addition, in the first end plate 12 according to the present invention, the fitting end 46 for connecting the external supply means or the exhaust system of the cooling water, fuel gas and air to each of the ports 42 and 44 has a first end. When the plate 12 is ejected, it is molded integrally with each of the ports 42 and 44, and a reinforcement 49 is inserted through the ports 42 and 44 and the fitting portion 46.

The reinforcing material 49 is a metal material, and its surface is inserted into an uneven surface so as not to be separated from the first end plate 12 made of plastic.

As described above, according to the present invention, it is possible to solve the problem of corrosion of the current collector plate and the end plate and thereby improve performance.

In addition, the number of parts, such as the removal of the insulating tape, and the size of the current collector plate, the fitting part, etc., can be reduced, and in particular, the current collector plate inserted into the end plate in preparation for the thickness of the conventional structure in which the current collector plate and the end plate are laminated. The size of the fuel cell stack can be reduced by the thickness of.

In addition, it is possible to reduce the mass production and manufacturing cost through injection molding, and the assembly work is facilitated by the integration of the current collector plate and the end plate.

Claims (5)

The current collector plate 22 is made of a non-conductive material and manufactured by injection molding. The current collector plate 22 is disposed on the inner surface thereof so as not to be exposed to the supply port 42 and the discharge port 44 of the coolant, fuel gas, and air. The unit cell 21 is inserted while only exposed the inner surface to be in contact, the installation unit 52 is installed integrally molded in which the external terminal 50 of the current collector plate 22 for external load connection is inserted. End plate of the fuel cell stack. According to claim 1, wherein the external terminal 50 is exposed on the outer surface of the end plate (12, 14) so that one end can be connected to the external load and the other end is screwed structure is fastened to the current collector plate 22 An electrically conductive means 54, an adapter 56 which is inserted into the mounting portion 52 and connected to the current collector plate 22 separately from the electrically conductive means 54, and the electrically conductive means 54 and the adapter ( 56) End plate of the fuel cell stack, characterized in that it comprises a washer (58) for connecting. The end plate of the fuel cell stack according to claim 1, wherein each of the ports (42, 44) is integrally formed with a fitting (46) for external connection. 4. An end plate of a fuel cell stack according to claim 3, wherein a reinforcing member (49) is inserted over each of said ports (42, 44) and fitting parts (46). The end plate of the fuel cell stack according to claim 4, wherein the reinforcing member (49) has an uneven surface.