Composite bipolar plate and preparation method thereof

Abstract

The invention discloses a preparation method of a composite bipolar plate, which comprises the following steps: S01, placing a resin preform between two graphite flakes, and heating until the resin preform is in a molten state to obtain a molten graphite resin fiber material; s02, placing the molten graphite resin fiber material in the step S01 on a mold, and stamping to obtain a composite bipolar plate; in the step S01, the resin preform is prepared by the following method: heating a resin fiber prepreg to 120-200 DEG C, and then rolling graphite slurry on two side surfaces of the resin fiber prepreg to obtain the resin preform. The preparation method is simple and easy to implement, the preparation period of the bipolar plate is greatly shortened, the production efficiency is high, and the preparation method can be used for large-scale production of the bipolar plate. The prepared composite material bipolar plate is low in contact resistance, high in forming efficiency and good in performance, and can meet the use requirements of fuel cells.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cells, and in particular relates to a composite material bipolar plate and a preparation method thereof. Background Art

[0002] The bipolar plate (BP) of a fuel cell, also known as the flow field plate, is the "skeleton" of the fuel cell stack. It is assembled with the membrane electrode layer to form a fuel cell stack. It plays the role of supporting, collecting current, providing channels for coolant, and separating oxidants and reductants in the fuel cell.

[0003] At present, the common bipolar plate materials are graphite bipolar plates, metal bipolar plates and composite bipolar plates. Among them, composite bipolar plates have the excellent corrosion resistance of graphite plates and the high volume power density of metal plates, and have great development potential. Existing composite bipolar plates are mainly formed by heating and pressing, which generally takes 10 to 20 minutes. Even if fast-curing resin is used, the molding time is at least 3 to 5 minutes. The long molding time leads to low production efficiency and is difficult to meet the needs of actual production and use. Summary of the invention

[0004] The embodiment of the present invention provides a composite material bipolar plate and a preparation method thereof, aiming to solve the problem of long molding time and low production efficiency of existing composite bipolar plates. Through this application, the molding time of the composite bipolar plate can be shortened to within 10 seconds, effectively improving the production efficiency of the composite bipolar plate.

[0005] In order to solve the above technical problems, the present invention first provides a method for preparing a composite material bipolar plate, comprising the following steps:

[0006] S01, placing a resin preform between two graphite sheets, and heating the resin preform until the resin preform is in a molten state to obtain a molten graphite resin fiber material;

[0007] S02, placing the molten graphite resin fiber material in step S01 on a mold, and stamping it to obtain a composite material bipolar plate.

[0008] As a preferred embodiment, in step S01,

[0009] The resin preform is prepared by the following method: heating the resin fiber prepreg to 120°C to 200°C, and then rolling the graphite slurry on both sides of the resin fiber prepreg to obtain the resin preform. A layer of graphite slurry is covered on the thermoplastic resin fiber prepreg by hot rolling, and the purpose of hot rolling is mainly to soften the thermoplastic resin so as to better combine with the graphite slurry.

[0010] The mass of the graphite slurry is 5% of the mass of the resin fiber prepreg; and the resin fiber prepreg is a thermoplastic resin fiber prepreg.

[0011] The thermoplastic resin is one of PEEK (polyetheretherketone), PPS (polyphenylene sulfide), TPI (polyimide), PA6 (polyamide 6) or PAEK (polyaryletherketone);

[0012] The fiber is T300 fiber or T700 fiber.

[0013] The resin fiber prepreg is one of a unidirectional material prepreg, a plain fabric prepreg or a twill fabric prepreg.

[0014] The graphite slurry is expanded graphite slurry; the expanded graphite slurry contains expanded graphite and a solvent, and the mass ratio of the expanded graphite to the solvent is 1:10; and the solvent is water.

[0015] The graphite sheet is graphite paper.

[0016] The heating temperature is 220°C to 380°C.

[0017] The heating is achieved by a heating stage.

[0018] As a preferred embodiment, in step S02,

[0019] The temperature of the upper mold of the mold is room temperature, and the temperature of the lower mold of the mold is half of the melting temperature of the thermoplastic resin. The molten resin will quickly cool down and solidify when it contacts the upper mold at room temperature, and will be quickly formed under the action of the punch press. The entire time from the material leaving the heating table to the completion of the forming is controlled within 10 seconds.

[0020] The stamping time is ≤10s; and the stamping is achieved by a stamping machine.

[0021] On the other hand, an embodiment of the present application further provides a composite material bipolar plate, which is prepared by the above-mentioned preparation method.

[0022] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0023] This application solves the problems of long manufacturing cycle and low production efficiency of composite bipolar plates for fuel cells from two aspects: materials (such as the selection and ratio of raw materials for bipolar plates) and processes (such as subsequent processing and the introduction of stamping technology), and provides solutions and technical support for the mass production of composite bipolar plates. The preparation method of this application is simple and easy to implement, which greatly shortens the preparation cycle of bipolar plates, has high production efficiency, and can be used for large-scale production of bipolar plates. The prepared composite bipolar plate has low contact resistance, high molding efficiency, good performance, and can meet the use needs of fuel cells. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0026] At present, the existing carbon fiber graphite composite bipolar plate has the problem of long preparation time and low production efficiency. In order to solve the above technical problems, the embodiment of the present application provides a method for preparing a composite material bipolar plate, comprising the following steps:

[0027] S01, placing a resin preform between two graphite sheets, and heating the resin preform until the resin preform is in a molten state to obtain a molten graphite resin fiber material;

[0028] S02, placing the molten graphite resin fiber material in step S01 on a mold, and stamping it to obtain a composite material bipolar plate.

[0029] As a preferred embodiment, in step S01,

[0030] The resin preform is prepared by the following method: heating the resin fiber prepreg to 120°C to 200°C (depending on actual needs, it can be 120°C, or 150°C, or 180°C, or 200°C, etc.), and then rolling the graphite slurry on both sides of the resin fiber prepreg to obtain the resin preform.

[0031] The mass of the graphite slurry is 5% of the mass of the resin fiber prepreg; and the resin fiber prepreg is a thermoplastic resin fiber prepreg.

[0032] The thermoplastic resin is one of PEEK (polyetheretherketone), PPS (polyphenylene sulfide), TPI (polyimide), PA6 (polyamide 6) or PAEK (polyaryletherketone);

[0033] The fiber is T300 fiber or T700 fiber.

[0034] The resin fiber prepreg is one of a unidirectional material prepreg, a plain fabric prepreg or a twill fabric prepreg.

[0035] The graphite slurry is an expanded graphite slurry; the expanded graphite slurry contains expanded graphite and a solvent, the mass ratio of the expanded graphite to the solvent is 1:10; the solvent is water. The graphite sheet is a graphite paper. The thickness of the graphite paper is generally 0.05mm-1mm (depending on actual needs, it can be 0.05mm, or 0.06mm, or 0.08mm, or 1mm, etc.), preferably 0.08mm. The heating temperature is 220°C to 380°C (depending on actual needs, it can be 220°C, or 250°C, or 300°C, or 380°C, etc.).

[0036] The heating is achieved by a heating stage.

[0037] As a preferred embodiment, in step S02,

[0038] The temperature of the upper mold of the mold is room temperature, and the temperature of the lower mold of the mold is half of the melting temperature of the thermoplastic resin. The molten resin will quickly cool down and solidify when it contacts the upper mold at room temperature, and will be quickly formed under the action of the punch press. The entire time from the material leaving the heating table to the completion of the forming is controlled within 10 seconds.

[0039] The stamping time is ≤10s; and the stamping is achieved by a stamping machine.

[0040] On the other hand, an embodiment of the present application further provides a composite material bipolar plate, which is prepared by the above-mentioned preparation method.

[0041] This application solves the problems of long manufacturing cycle and low production efficiency of composite bipolar plates for fuel cells from two aspects: materials (such as the selection and ratio of raw materials for bipolar plates) and processes (such as subsequent processing and the introduction of stamping technology), and provides solutions and technical support for the mass production of composite bipolar plates. The preparation method of this application is simple and easy to implement, which greatly shortens the preparation cycle of bipolar plates, has high production efficiency, and can be used for large-scale production of bipolar plates. The prepared composite bipolar plate has low contact resistance, high molding efficiency, good performance, and can meet the use needs of fuel cells.

[0042] Example 1

[0043] A method for preparing a composite material bipolar plate comprises the following steps:

[0044] S01, placing a resin preform between two graphite sheets, and heating the resin preform until the resin preform is in a molten state to obtain a molten graphite resin fiber material;

[0045] S02, placing the molten graphite resin fiber material in step S01 on a mold, and stamping it to obtain a composite material bipolar plate.

[0046] In step S01,

[0047] The resin preform is prepared by the following method: heating the resin fiber prepreg to 150° C., and then rolling the graphite slurry on both sides of the resin fiber prepreg to obtain the resin preform.

[0048] The mass of the graphite slurry is 5% of the mass of the resin fiber prepreg; and the resin fiber prepreg is a thermoplastic resin fiber prepreg.

[0049] The thermoplastic resin is PPS;

[0050] The fiber is T300 fiber.

[0051] The resin fiber prepreg is a unidirectional material prepreg.

[0052] The graphite slurry is expanded graphite slurry; the expanded graphite slurry contains expanded graphite and a solvent, the mass ratio of the expanded graphite to the solvent is 1:10; the solvent is water. The graphite sheet is graphite paper, and the thickness of the graphite paper is 0.05 mm.

[0053] The heating temperature is 280° C., so that the PPS is in a molten state and pre-compacted. The heating is achieved by a heating table.

[0054] In step S02,

[0055] The temperature of the upper mold of the mold is room temperature, and the temperature of the lower mold of the mold is 140° C. The resin in the molten state will quickly cool down and solidify when it contacts the upper mold at room temperature, and will be quickly formed under the action of the punch press. The time from the material leaving the heating table to the mold is controlled within 5 seconds, and the time to the completion of the stamping molding is controlled within 10 seconds.

[0056] The stamping time is ≤5s; and the stamping is achieved by a stamping machine.

[0057] The prepared composite bipolar plate was cut and then tested for air tightness and related performance. The results showed that the air tightness of the composite bipolar plate was 0.2sccm and the contact resistance was 6mΩ·cm. 2 , and the electrical conductivity is 350S / cm, that is, the composite bipolar plate obtained in the present application meets the use requirements of fuel cells and can meet the use needs of fuel cells.

[0058] Example 2

[0059] A method for preparing a composite material bipolar plate comprises the following steps:

[0060] S01, placing a resin preform between two graphite sheets, and heating the resin preform until the resin preform is in a molten state to obtain a molten graphite resin fiber material;

[0061] S02, placing the molten graphite resin fiber material in step S01 on a mold, and stamping it to obtain a composite material bipolar plate.

[0062] In step S01,

[0063] The resin preform is prepared by the following method: heating the resin fiber prepreg to 150° C., and then rolling the graphite slurry on both sides of the resin fiber prepreg to obtain the resin preform.

[0064] The mass of the graphite slurry is 5% of the mass of the resin fiber prepreg; and the resin fiber prepreg is a thermoplastic resin fiber prepreg.

[0065] The thermoplastic resin is PEEK;

[0066] The fiber is T700 fiber.

[0067] The resin fiber prepreg is a plain weave fabric prepreg.

[0068] The graphite slurry is expanded graphite slurry; the expanded graphite slurry contains expanded graphite and a solvent, the mass ratio of the expanded graphite to the solvent is 1:10; the solvent is water. The graphite sheet is graphite paper, and the thickness of the graphite paper is 0.08 mm.

[0069] The heating temperature is 220° C., so that the PEEK is in a molten state and pre-compacted. The heating is achieved by a heating table.

[0070] In step S02,

[0071] The temperature of the upper mold of the mold is room temperature, and the temperature of the lower mold of the mold is 110° C. The resin in the molten state will quickly cool down and solidify when it contacts the upper mold at room temperature, and will be quickly formed under the action of the punch press. The time from the material leaving the heating table to the mold is controlled within 5 seconds, and the time to the completion of the stamping molding is controlled within 10 seconds.

[0072] The stamping time is ≤5s; and the stamping is achieved by a stamping machine.

[0073] The prepared composite bipolar plate was cut and then tested for air tightness and related performance. The results showed that the air tightness of the composite bipolar plate was 0.19sccm and the contact resistance was 6mΩ·cm. 2 , and the electrical conductivity is 350S / cm, that is, the composite bipolar plate obtained in the present application meets the use requirements of fuel cells and can meet the use needs of fuel cells.

[0074] Example 3

[0075] A method for preparing a composite material bipolar plate comprises the following steps:

[0076] S01, placing a resin preform between two graphite sheets, and heating the resin preform until the resin preform is in a molten state to obtain a molten graphite resin fiber material;

[0077] S02, placing the molten graphite resin fiber material in step S01 on a mold, and stamping it to obtain a composite material bipolar plate.

[0078] In step S01,

[0079] The resin preform is prepared by the following method: heating the resin fiber prepreg to 150° C., and then rolling the graphite slurry on both sides of the resin fiber prepreg to obtain the resin preform.

[0080] The mass of the graphite slurry is 5% of the mass of the resin fiber prepreg; and the resin fiber prepreg is a thermoplastic resin fiber prepreg.

[0081] The thermoplastic resin is TPI (polyimide);

[0082] The fiber is T300 fiber.

[0083] The resin fiber prepreg is a twill fabric prepreg.

[0084] The graphite slurry is expanded graphite slurry; the expanded graphite slurry contains expanded graphite and a solvent, and the mass ratio of the expanded graphite to the solvent is 1:10; and the solvent is water.

[0085] The graphite sheet is graphite paper, and the thickness of the graphite paper is 1 mm.

[0086] The heating temperature is 380° C., so that the TPI is in a molten state and pre-compacted. The heating is achieved by a heating table.

[0087] In step S02,

[0088] The temperature of the upper mold of the mold is room temperature, and the temperature of the lower mold of the mold is 190° C. The resin in the molten state will quickly cool down and solidify when it contacts the upper mold at room temperature, and will be quickly formed under the action of the punch press. The time from the material leaving the heating table to the mold is controlled within 5 seconds, and the time until the stamping is completed is controlled within 10 seconds.

[0089] The stamping time is ≤5s; and the stamping is achieved by a stamping machine.

[0090] The prepared composite bipolar plate was cut and then tested for air tightness and related performance. The results showed that the air tightness of the composite bipolar plate was 0.18sccm and the contact resistance was 6mΩ·cm. 2 , and the electrical conductivity is 350S / cm, that is, the composite bipolar plate obtained in the present application meets the use requirements of fuel cells and can meet the use needs of fuel cells.

[0091] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a composite material bipolar plate, characterized in that: The steps include: S01, placing a resin preform between two graphite sheets, and heating the resin preform until the resin preform is in a molten state to obtain a molten graphite resin fiber material; S02, placing the molten graphite resin fiber material in step S01 on a mold, and stamping to obtain a composite material bipolar plate; In step S01, the resin preform is prepared by the following method: heating the resin fiber prepreg to 120°C to 200°C, and then rolling the graphite slurry on both sides of the resin fiber prepreg to obtain the resin preform.

2. The method for preparing a composite material bipolar plate according to claim 1, characterized in that: The mass of the graphite slurry is 5% of the mass of the resin fiber prepreg; and the resin fiber prepreg is a thermoplastic resin fiber prepreg.

3. The method for preparing a composite material bipolar plate according to claim 2, characterized in that: The thermoplastic resin is one of PEEK, PPS, TPI, PA6 or PAEK; The fiber is T300 fiber or T700 fiber.

4. The method for preparing a composite material bipolar plate according to claim 1, characterized in that: The resin fiber prepreg is one of a unidirectional material prepreg, a plain fabric prepreg or a twill fabric prepreg.

5. The method for preparing a composite material bipolar plate according to claim 1, characterized in that: The graphite slurry is expanded graphite slurry; the expanded graphite slurry contains expanded graphite and a solvent, and the mass ratio of the expanded graphite to the solvent is 1:10; and the solvent is water.

6. The method for preparing a composite material bipolar plate according to claim 1, characterized in that: In step S01, the graphite sheet is graphite paper.

7. The method for preparing a composite material bipolar plate according to claim 1, characterized in that: In step S01, the heating temperature is 220°C to 380°C; the heating is achieved by a heating platform.

8. The method for preparing a composite material bipolar plate according to claim 1, characterized in that: In step S02 , the temperature of the upper mold of the mold is room temperature, and the temperature of the lower mold of the mold is half of the melting temperature of the thermoplastic resin.

9. The method for preparing a composite material bipolar plate according to claim 1, characterized in that: In step S02, the stamping time is ≤10s; the stamping is achieved by a stamping machine.

10. A composite material bipolar plate, characterized in that: The composite material bipolar plate is prepared by the preparation method according to any one of claims 1 to 9.