JP2006286215A - Method of processing resin coated metal plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a processing method of a resin coated metal plate which can form easily a fine and small cooling medium passage fixed around a heated part because of heat diffused from electronic devices fitted with electronic parts, personal computers, fuel cells or the like, and provide a fuel cell. <P>SOLUTION: A rough surface layer (11) is made on at least one side of a metal base plate (1) and a resin coated metal plate (3) coated with thermoplastic resin layer (2) on the rough surface layer (11) is cold formed by a mold into continuous grooves (4) of a cross-sectional concave shape. Two sheets of the resin coated metal plates (3) having the continuous grooves (4) are positioned so that the bottom side of cross-sectional concave grooves (4) are on opposite side each other and are heat-pressed to be welded with the thermoplastic resin layers (2) except grooved areas, and a part of the resin coated metal plate (3) is bonded, as well as a cylindrical part (5) of which the inner surface is coated with the thermoplastic resin layer (2) is formed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of processing a resin-coated metal plate, and more particularly to a metal separator used in a fuel cell (for example, a solid polymer electrolyte type fuel cell), and a liquid junction (through a cooling medium, a cooling system pipe or a radiator). It is related with the processing method which can form easily the refrigerant | coolant flow path which can prevent the phenomenon in which an electric current flows into the.

2. Description of the Related Art In recent years, electronic devices equipped with electronic components, personal computers, fuel cells, and the like have been cooled around a fine refrigerant flow path around a portion that generates heat for the purpose of dissipating generated heat.
The formation of such a refrigerant flow path will be described below using an example of a fuel cell.
In a fuel cell, specifically a solid polymer electrolyte fuel cell, a membrane comprising an electrolyte membrane comprising an ion exchange membrane, an anode disposed on one surface of the electrolyte membrane, and a cathode disposed on the other surface of the electrolyte membrane A plurality of single cells comprising an electrode assembly (MEA) and a separator that forms a fluid flow path for supplying fuel gas (hydrogen) and oxidizing gas (oxygen, usually air) to the anode and cathode Stack the cells to form a cell stack, and place terminals (electrode plates), insulators, and end plates at both ends of the cell stack in the cell stack direction, tighten the cell stack in the cell stack direction, and place the cell stack outside the cell stack. It is comprised from the stack fixed with the fastening member (for example, tension plate) extended in this. In the separator, a refrigerant flow path is formed between cells or between modules, and cooling water is supplied to cool the fuel cell.

In a solid polymer electrolyte fuel cell, a reaction is carried out to convert hydrogen into hydrogen ions and electrons on the anode side, and the hydrogen ions move through the electrolyte membrane to the cathode side, and oxygen, hydrogen ions and electrons (adjacent to the cathode side). The electrons generated at the anode of the MEA come through the separator, or the electrons generated at the anode of the cell at one end of the cell stack come through an external circuit) to generate water.
Anode side: H ₂ → 2H + + 2e ⁻
Cathode side: 2H + + 2e ⁻ + (1/2) O ₂ → H ₂ O

Conventionally, in the fuel cell separator, one side is in contact with MEA and the opposite side is in contact with cooling water. The current leaks from the separator to the cooling water at the contact surface with the cooling water, and this current flows in the cell surface direction through the cooling water to reach the refrigerant manifold, and flows adjacent to the cell surface in the refrigerant manifold. It flows to the opposite pole of a nearby cell, and the output performance that should be obtained is reduced (decreased). This leakage current tends to increase as a result of decreasing the electrical resistance in the cooling water portion by downsizing the separator and aiming for long-term use of the cooling water. Moreover, electric corrosion around the cooling water in which leakage current is generated becomes a problem.
In order to prevent such a liquid junction, for example, in Patent Document 1, the fuel cell stack is a laminated body of a cooling cell and a power generation cell, the refrigerant supplied into the cooling cell is insulated from the power generation cell, and the cooling cell is A structure is disclosed in which power generation cells arranged between each other are connected by a conductive means.

  However, in this method, an insulating material and a conductive plate are arranged on both sides of the cooling cell, and the outer peripheral portion of the conductive plate is connected outside the stack, so that the size of the connecting portion protruding out of the stack is also a covering portion for insulation. There is a problem that the distance between adjacent cooling cells cannot be reduced in consideration of mutual interference. Furthermore, since a conductive plate having a thickness corresponding to the rated current is required, the conductive plate cannot be thinned. In this respect, there is a problem that the fuel cell stack cannot be reduced in size.

  Therefore, in Patent Document 2, for example, a pair of conductive plates are connected and formed at portions other than the refrigerant passage, so that the conductivity is maintained, while the inner wall surface of the conductive plate constituting the refrigerant passage is coated with an insulating material. It has been proposed to insulate the inside of the refrigerant passage.

  However, it has been technically difficult to selectively energize portions other than the cooling passages formed in the pair of conductive plates.

JP 2001-332288 A JP 2004-127786 A

  The present invention is a metal separator used in a fuel cell (for example, a solid polymer electrolyte type fuel cell), and a liquid junction caused by a cooling medium (a phenomenon in which an electric current flows to a cooling system pipe, a radiator, etc. via the cooling medium). It is an object of the present invention to provide a method for processing a resin-coated metal plate that can easily form a refrigerant flow path capable of preventing the above.

The present invention has been found to provide a method for processing a resin-coated metal plate that can solve the above-described problems,
1. A metal-coated metal plate (3) formed by providing a rough surface layer (11) on at least one surface of the metal substrate (1) and covering the rough surface layer (11) with a thermoplastic resin layer (2) is cooled by a mold. A continuous groove portion (4) having a concave cross section is formed by inter-processing, and two resin-coated metal plates (3) having the continuous groove portion (4) are opposed to each other with the bottom surface of the concave groove portion (4) being cross section The thermoplastic resin layer (2) other than the grooves is fused by being placed on the side and hot pressed to join a part of the resin-coated metal plate (3) and the inner surface is the thermoplastic resin layer (2). A method of processing a resin-coated metal plate, characterized in that a cylindrical part (5) covered with is formed.
2. 2. The maximum surface roughness Ry (measured according to JIS B0601) of the rough surface layer (11) provided on at least one surface of the metal substrate (1) is in the range of 0.3 to 10 μm. Processing method for resin-coated metal sheet.

3. The thickness of the thermoplastic resin layer (2) is in the range of (Ry) × 1.1 times to (Ry) × 3.0 times the maximum surface roughness (Ry) of the metal substrate (1). 3. A method for processing a resin-coated metal sheet according to 1 or 2 above.
4). 4. The method for processing a resin-coated metal plate according to any one of 1 to 3, wherein the metal substrate (1) is selected from the group consisting of stainless steel, titanium, aluminum, copper, nickel, and steel.
5. Any one of 1 to 4 above, wherein the cylindrical portion (5) is a refrigerant flow path, and the joined portion of the resin-coated metal plate (3) is used for a metal separator of a fuel cell having electrical conductivity. The resin-coated metal plate described.
6). A fuel cell comprising the metal separator according to 5 above.

  According to the present invention, a small and small refrigerant flow path, particularly a fuel cell (e.g., a fuel cell (e.g., This is a metal separator used in solid polymer electrolyte fuel cells), and it is easy to create a refrigerant flow path that can prevent liquid junctions (a phenomenon in which current flows through cooling medium, cooling system piping, radiators, etc.). A method for processing a resin-coated metal plate that can be formed, and a fuel cell can be provided.

The present invention will be described in detail below.
The resin-coated metal plate in the present invention is processed by the method shown in the process schematic diagram of FIG.
(A) A rough surface layer (11) is provided on at least one surface of the metal substrate (1).
(B) A thermoplastic resin layer (2) is coated on the rough surface layer (11) to obtain a resin-coated metal plate (3).
(C) The resin-coated metal plate (3) is cold-worked by the mold (6) to form a continuous groove (4) having a concave cross section.
(D) Two resin-coated metal plates (3) having continuous groove portions (4) are arranged so that the bottom surfaces of the groove portions (4) having a concave cross section are opposite to each other, and heated by a hot press (7). Press.

Since the resin-coated metal plate in the present invention can be suitably used as a metal separator for a fuel cell, a processing method as the metal separator will be described below.
(A) In a fuel cell having a metal separator having a refrigerant contact surface in contact with a refrigerant, a thermoplastic resin layer on a portion of the metal separator which is a metal substrate (1) in contact with the refrigerant, excluding the corresponding portion of the fuel cell power generation unit In order to form the electrical insulating layer comprising (2), it is necessary to first roughen the metallic separator surface that contacts the refrigerant. The roughening of the metallic separator surface in contact with the refrigerant has a maximum surface roughness Ry in the range of 0.3 to 10 μm, preferably in the range of 0.5 to 5.0 μm, and more preferably in the range of 0.5 to 3.0 μm. Range.
Here, the measurement method of the maximum surface roughness Ry may be measured in accordance with JIS B0601, and only the reference length is extracted from the roughness curve in the direction of the average line, and the peak line and valley line of this extracted part are extracted. Is measured in the direction of the vertical magnification of the roughness curve, and this value is expressed in micrometers (μm).

If the maximum surface roughness is less than 0.5 μm, not only is the adhesion of the electrical insulating layer insufficient,
On the other hand, when the maximum surface roughness exceeds 10 μm, the metal separator obtained by the method of the present invention is likely to have a reduced electrical conductivity. The problem of inferiority is likely to occur.
In addition, as the metal separator as the metal substrate (1), stainless steel, titanium, aluminum, copper, nickel, and steel, which can easily form the corrosion resistance, low cost, and gas and refrigerant flow path, can be suitably used.

  Various etching methods can be used to roughen the metallic separator surface in contact with the refrigerant. For example, it is preferable to determine appropriately according to the type of metal by mechanical etching using an abrasive, chemical etching using chemicals, electrolytic etching using anodic dissolution using electric energy, or the like.

(B) Next, the rough surface layer (11) roughened by the above-described method is completely covered with the electrical insulating layer as the thermoplastic resin layer (2) to obtain a resin-coated metal plate (3). As a thermoplastic resin to be used, for example,
Polyolefin (PO) resins such as homopolymers or copolymers containing ethylene or polyolefin elastomers, amorphous polyolefin resins (APO) such as cyclic polyolefins, polystyrene resins such as polystyrene (PS), ABS, SBS, etc. Hydrogenated styrene elastomers such as SEBS, polyvinyl chloride (PVC) resins, polyvinylidene chloride (PVDC) resins, polymethyl methacrylate (PMMA), acrylic resins such as copolymerized acrylics, polyethylene terephthalate (PET), etc. Polyamide (PA) resin such as polyester resin, nylon 6, nylon 12, copolymer nylon, polyimide (PI) resin, polyetherimide (PEI) resin, polysulfone (PS) resin, polyethersulfone (PES) resin , Polya Doimide (PAI) resin, polyether ether ketone (PEEK) resin, polyphenylene sulfide (PPS) resin, polyphenylene ether (PPE), polyoxymethylene (POM) resin, polycarbonate (PC) resin, polyvinyl butyral (PVB) resin, poly Arylate (PAR) resin, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer (THV), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), vinylidene fluoride (PVDF), fluorine Fluorine resins or elastomers such as vinyl fluoride (PVF), (meth) acrylate resins, and the like.

Among the thermoplastic resins exemplified above, polyolefin (PO) resin or polyolefin elastomer, amorphous polyolefin resin such as cyclic polyolefin, polyimide (PI) resin having excellent heat resistance and chemical resistance. , Polyetherimide (PEI) resin, polysulfone (PS) resin, polyethersulfone (PES) resin, polyamideimide (PAI) resin, polyetheretherketone (PEEK) resin, polyphenylene sulfide (PPS) resin, polyphenylene ether ( PPE), polyoxymethylene (POM) resin, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer (THV), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), vinylidene fluoride (PVDF), vinyl fluoride (P F), the fluorocarbon resin or elastomer etc. are preferred.
More preferably, a polyetherimide (PEI) resin, a polyethersulfone (PES) resin, a fluorine resin, or an elastomer is used.

  The method of completely covering the surface of the metal separator that is in contact with the roughened refrigerant with the electrical insulating layer that is the thermoplastic resin layer (2) is not particularly limited, but the coating is applied by dissolving or dispersing the electrical insulating layer in a solvent. A method of coating the roughened separator surface after the production is preferable. As a coating method, various coating methods such as an air doctor coater, a blade coater, a rod coater, a knife coater, a squeeze coater, an impregnation coater, a reverse roll coater, a transfer roll coater, a kiss roll coater, and a cast coater can be applied.

The thickness of the electrical insulating layer which is the thermoplastic resin layer (2) covering the roughened metal separator surface is equal to the surface roughness Ry (measured in accordance with JIS B0601) of the separator surface in contact with the refrigerant. On the other hand, a range of Ry × 1.1 times to Ry × 3.0 times, preferably a range of Ry × 1.2 to Ra × 2.0 times is preferable. Here, the method for measuring the maximum surface roughness Ry is the same as described above.
If the thickness of the electrical insulating layer is less than Rya × 1.1 times the maximum surface roughness (Ry) of the metal separator surface that contacts the refrigerant, the surface roughness is almost equal to the thickness of the electrical insulating layer. Pinholes are generated in the electrically insulating layer, and ground faults and liquid junctions due to the cooling medium are likely to occur. In addition, if the thickness of the electrical insulating layer exceeds Ry × 3.0 times the surface roughness (Ry) of the separator surface in contact with the refrigerant, the thickness of the electrical insulating layer is thicker than the surface roughness. The problem that the electrical conductivity of the metallic separator provided with the flow path finally obtained by the method of the present invention is likely to occur.

(C) Next, the resin-coated metal plate (3) obtained by the above method is cold-worked by the mold (6) to form a continuous groove (4) having a concave cross section. In a fuel cell, it is necessary to form a flow path of fuel gas and oxidizing gas between the separator and the electrode, and a flow path of refrigerant between the separator and the separator. It is necessary to provide a large number of protrusions and grooves for the purpose. In order to form the protrusion and the groove, a method of forming the protrusion and the groove by pressing using a predetermined mold to form a separator having a predetermined shape is preferable from the viewpoint of productivity.

(D) Next, two resin-coated metal plates (3) having the continuous groove (4) are arranged so that the bottom surfaces of the concave grooves (4) are opposite to each other, and a hot press machine ( 7) Hot press.
As for the conditions of the hot pressing, it is necessary to perform hot pressing at a temperature equal to or higher than the flow start temperature of the electrical insulating layer, and to bring the joining portion other than the groove (4) into an energized state. As described above, the electrical insulating layer is a thermoplastic resin, and the flow start temperature corresponds to the melting point when the thermoplastic resin is a crystalline resin and the glass transition temperature when the thermoplastic resin is an amorphous resin. The groove portions (4) having the concave cross section (4) face each other by hot pressing, and a cylindrical portion (5) is formed which becomes a refrigerant flow path whose inner surface is covered with the thermoplastic resin layer (2).

Here, the pressure during hot pressing is in the range of 5 × 10 ^{5 to} 5 × 10 ⁶ Pa, preferably in the range of 5 × 10 ⁵ to 2 × 10 ⁶ Pa. If the pressure is less than 5 × 10 ⁵ Pa, a sufficient load is not applied, so that the adhesiveness of the joining portion of the two separators is insufficient, and the refrigerant in the refrigerant flow path that is the cylindrical portion (5) leaks or has resistance. Value is likely to increase. Further, when the pressure exceeds 5 × 10 ⁶ Pa, the gas and the refrigerant flow path, which are the cylindrical portions (5), cannot withstand the load and are likely to be deformed.

Hereinafter, although an example is described, the present invention is not limited to this.
[Experiment 1]

A metal separator having a flow path for a fuel cell was prepared in accordance with the process schematic shown in FIG.
(A) As the metal separator 1, the surface of SUS304 (thickness 0.1 mm) was roughened by using a jet scrubbing machine (manufactured by Ishii Co., Ltd.) to provide a rough surface layer 11. The roughening conditions were as follows. Alumina (Sac Random # 150, Nippon Carlit Co., Ltd.) was used as an abrasive, and the surface of SUS304 was applied at an abrasive concentration of 20%, a conveyance speed of 1.0 m / min, and a pressure of 0.4 MPa. Polished. As shown in Table 1, the surface roughness of SUS304 (No. 1) after polishing was a center line average surface roughness Ra = 0.31 μm and a maximum surface roughness Ry = 2.52 μm.

(B) As an electrical insulation layer, PES (polyethersulfone) (Sumitomo Chemical Co., Ltd., SUMIKAEXCEL PES5003P glass transition temperature 230 ° C.) of dimethylformamide / cyclohexanone = 1/4 (weight ratio) A paint was prepared by dissolving in a mixed solvent so that the solid content concentration was 12% by weight. This paint is applied to the polished surface of SUS304 (No. 1) after polishing with the bar coater (“Matsuo Sangyo” # 24), and the solvent is dried at 300 ° C. to have a thickness of 4 μm. A layer was formed to prepare a resin-coated metal plate 3 (No. 1) flat plate.

The volume resistance value of the resin-coated metal plate 3 (No. 1) flat plate was measured in accordance with JIS K 7194 as follows. The volume resistance value was measured by bringing an ASP probe into contact with the electrical insulating layer side.
1. Measuring device Loresta HP (Mitsubishi Chemical Corporation)
2. Measurement method Four-terminal four-probe method (ASP type probe)
3. Measurement applied current 100mA
As a result, as shown in Table 1, the volume resistance value of the resin-coated metal plate 3 (No. 1) flat plate measured from the electric insulating layer side is 10 ⁷ Ωcm or more, which is the measurement limit of the measuring device, and The surface of the metal plate (SUS304) on the insulating layer side was an insulator.

(C) Resin-coated metal plate 3 (No. 1) flat plate was press-molded to form continuous grooves 4. The shape of the groove 4 is corrugated, the pitch of the flow path is 3 mm, and the height difference between the corrugated convex part and the concave part is 0.5 mm, and a press molding machine ("AMADA Co., Ltd. Torque" is used. Pack press Molding was performed at room temperature at a press speed of 45 spm). After the molding, the electric insulating layer was not cracked and the adhesion between the insulating layer and the metal plate (SUS304) was good.

(D) Two resin-coated metal plates (No. 1) having continuous groove portions 4 were arranged so that the bottom surfaces of the groove portions 4 having a concave cross section were opposite to each other, and were hot-pressed by a hot press 7. The hot pressing was performed at a temperature of 300 ° C., a pressure of 1.0 × 10 ⁶ Pa, and a time of 5 minutes. The adhesiveness of the two resin-coated metal plates (No. 1) after hot pressing was good, and there was no deformation of the cylindrical part 5 which is a gas and refrigerant flow path.

The electrical resistance of the metal separator formed with the channel obtained by the above method was measured by the method shown in the schematic diagram of FIG.
1. Measuring device Resistance meter: YMR-3 type (manufactured by Yamazaki Seiki Laboratory Co., Ltd.)
Load device: YSR-8 type (manufactured by Yamazaki Seiki Laboratory Co., Ltd.)
Electrodes: 2 brass flat plates (area 1 square inch, mirror finish)
2. Measurement conditions Method: 4-terminal method Applied current: 10 mA (AC, 287 Hz)
Open terminal voltage: 20 mV peak or less Surface pressure: 1.0 × 10 ⁶ Pa
As a result of the measurement, as shown in Table 1, the resistance value of the two metal separators having the flow path was 1.5 mΩ, which was a good energized state. Moreover, the inner surface of the cylindrical part 5 which is a gas and refrigerant flow path was completely insulated by the electrical insulating layer, and there was no liquid junction.
[Experiment 2]

  As in Experiment 1, the polishing agent was changed to alumina (Sac Random # 220, manufactured by Nippon Carlit Co., Ltd.), and SUS304 (thickness 0.1 mm) was polished. As shown in Table 1, the surface roughness of SUS304 (No. 2) after polishing was a center line average surface roughness Ra = 0.19 μm and a maximum surface roughness Ry = 1.61 μm.

  As an electrical insulating layer, apply the same paint as in Experiment 1 on the polished surface of SUS304 (No. 2) after polishing with a bar coater (“Matsuo Sangyo” # 12) and dry the solvent at 300 ° C. A 2 μm thick electric insulation layer was formed to prepare a resin-coated metal plate (No. 2) flat plate.

As a result of measuring the volume resistance value of the resin-coated metal plate (No. 2) flat plate in the same manner as in Experiment 1, the volume resistance value measured from the electrical insulating layer side of the resin-coated metal plate (No. 2) flat plate is As shown in FIG. 1, the measurement limit of the measurement apparatus was 10 ⁷ Ωcm or more, and the surface of the metal plate (SUS304) on the electrical insulating layer side was an insulator.

  A resin-coated metal plate (No. 2) flat plate was press-molded by the same method as in Experiment 1 to form a continuous groove 4. After the molding, the electric insulating layer was not cracked and the adhesion between the insulating layer and the metal plate (SUS304) was good.

  Two resin-coated metal plates (No. 2) having continuous grooves 4 were hot-pressed in the same manner as in Experiment 1. The adhesiveness of the two resin-coated metal plates (No. 2) after hot pressing was good, and there was no deformation of the gas and refrigerant flow paths.

As a result of measuring the electric resistance of the two metal separators formed with the flow path obtained by the above method in the same manner as in Experiment 1, the resistance value was 1.0 mΩ as shown in Table 1, indicating that the electric current was in a good energized state. It was.
Moreover, the inner surface of the cylindrical part 5 which is a gas and refrigerant flow path was completely insulated by the electrical insulating layer, and there was no liquid junction.
[Experiment 3]

  On the polished surface of surface polished SUS304 (No. 1) created in Experiment 1, apply the same paint created in Experiment 1 with a bar coater (“Matsuo Sangyo” # 48) and dry the solvent at 300 ° C. Then, an electric insulating layer having a thickness of 8 μm was formed to prepare a resin-coated metal plate (No. 3) flat plate.

As a result of measuring the volume resistance value of the resin-coated metal plate (No. 3) flat plate in the same manner as in Experiment 1, the volume resistance value measured from the electric insulating layer side of the resin-coated metal plate (No. 3) flat plate is As shown in FIG. 1, the measurement limit of the measurement apparatus was 10 ⁷ Ωcm or more, and the surface of the metal plate (SUS304) on the electrical insulating layer side was an insulator.

  A resin-coated metal plate (No. 3) flat plate was press-molded by the same method as in Experiment 1 and press-molded by the same method as in Experiment 1 to form a continuous groove 4. After the molding, the electric insulating layer was not cracked and the adhesion between the insulating layer and the metal plate (SUS304) was good.

  Two resin-coated metal plates (No. 3) having continuous grooves 4 were hot-pressed in the same manner as in Experiment 1. The adhesiveness of the two resin-coated metal plates (No. 3) after hot pressing was good, and there was no deformation of the gas and refrigerant flow paths.

As a result of measuring the electrical resistance of the two metal separators formed with the flow path obtained by the above method in the same manner as in Experiment 1, the resistance value is 20,000 mΩ or more, which is the limit of the measuring apparatus as shown in Table 1. there were.
[Experiment 4]

  The same paint prepared in Experiment 1 is applied to the polished surface of the surface polished SUS304 (No. 1) prepared in Experiment 1 with a bar coater (“Matsuo Sangyo” # 16), and the solvent is dried at 300 ° C. Then, an electric insulating layer having a thickness of 2.7 μm was formed, and a resin-coated metal plate (No. 4) flat plate was prepared.

As a result of measuring the volume resistance value of the resin-coated metal plate (No. 4) flat plate in the same manner as in Experiment 1, the volume resistance value measured from the electrical insulating layer side of the resin-coated metal plate (No. 4) flat plate is As shown in 1, it was not constant. As a result of observing the surface of the resin-coated metal plate (No. 4) flat plate on the side of the electric insulation layer with a microscope (Digital HD Microscope VH-7000, manufactured by Keyence Corporation) at a magnification of 50, a minute pinhole is present. I found out.

  As shown in Table 1, in the metal separator formed with the flow paths obtained in Experiments 1 and 2, the fuel cell power generation unit corresponding part maintains a good energized state, while the portions other than the fuel cell power generation unit corresponding part are It was in an insulating state and was particularly suitable for preventing liquid junction due to the cooling medium.

  On the other hand, in Experiment 3, since the thickness of the electrical insulating layer is thicker than three times the maximum surface roughness Ry of the metal plate, it is found that the resistance value of the fuel cell power generation unit corresponding part is large and the internal resistance of the fuel cell is increased. It was. In Experiment 4, since the thickness of the electrical insulating layer is less than 1.1 times the maximum surface roughness Ry of the metal plate, minute pinholes are likely to occur in the electrical insulating layer. It was found that liquid junctions are likely to occur.

It is the schematic which shows the process of the processing method of the resin coating metal plate of this invention. It is the schematic which shows the measuring method of the electrical resistance of the metal separator which formed the flow path.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Metal substrate 11 ... Rough surface layer 2 ... Thermoplastic resin layer 3 ... Resin coating metal plate 4 ... Groove part 5 ... Cylindrical part

Claims (6)

A metal-coated metal plate (3) formed by providing a rough surface layer (11) on at least one surface of the metal substrate (1) and covering the rough surface layer (11) with a thermoplastic resin layer (2) is cooled by a mold. A continuous groove portion (4) having a concave cross section is formed by inter-processing, and two resin-coated metal plates (3) having the continuous groove portion (4) are opposed to each other with the bottom surface of the concave groove portion (4) being cross section The thermoplastic resin layer (2) other than the grooves is fused by being placed on the side and hot pressed to join a part of the resin-coated metal plate (3) and the inner surface is the thermoplastic resin layer (2). A method of processing a resin-coated metal plate, characterized in that a cylindrical part (5) covered with is formed. The maximum surface roughness Ry (measured according to JIS B0601) of the rough surface layer (11) provided on at least one surface of the metal substrate (1) is in the range of 0.3 to 10 µm. Method for processing a resin-coated metal plate. The thickness of the thermoplastic resin layer (2) is in the range of (Ry) × 1.1 times to (Ry) × 3.0 times the maximum surface roughness (Ry) of the metal substrate (1). The processing method of the resin-coated metal plate according to claim 1 or 2. The method for processing a resin-coated metal plate according to any one of claims 1 to 3, wherein the metal substrate (1) is selected from the group consisting of stainless steel, titanium, aluminum, copper, nickel, and steel. The cylindrical part (5) is a refrigerant flow path, and the joined part of the resin-coated metal plate (3) is used for a metal separator of a fuel cell having electrical conductivity. The resin-coated metal plate described in 1. A fuel cell comprising the metal separator according to claim 5 incorporated therein.

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