A composite bipolar plate and a method for manufacturing the same

Abstract

This invention discloses a method for preparing a composite bipolar plate, comprising the following steps: S01, placing a resin preform between two graphite sheets and heating it until the resin preform is in a molten state to obtain molten graphite resin fiber material; S02, placing the molten graphite resin fiber material from step S01 on a mold and stamping it to obtain a composite bipolar plate; in step S01, the resin preform is prepared by the following method: heating the resin fiber prepreg to 120℃~200℃, and then rolling graphite slurry onto both sides of the resin fiber prepreg to obtain the resin preform. The preparation method of this application is simple, easy to implement, greatly shortens the preparation cycle of the bipolar plate, 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, and good performance, meeting the needs of fuel cells.

Description

Technical Field

[0001] This invention belongs to the field of fuel cell technology, and particularly relates to a composite material bipolar plate and its preparation method. Background Technology

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

[0003] Currently, common bipolar plate materials include graphite bipolar plates, metal bipolar plates, and composite bipolar plates. Among them, composite bipolar plates possess the excellent corrosion resistance of graphite plates while also achieving the high volumetric power density of metal plates, showing great development potential. Existing composite bipolar plates are mainly formed by thermoforming, which generally takes 10 to 20 minutes. Even with the use of fast-curing resins, the molding time is still at least 3 to 5 minutes. This long molding time results in low production efficiency, making it difficult to meet the needs of actual production applications. Summary of the Invention

[0004] This invention provides a composite material bipolar plate and its preparation method, aiming to solve the problems 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] To address the aforementioned technical problems, this invention first provides a method for preparing a composite material bipolar plate, comprising the following steps:

[0006] S01. Place the resin preform between two graphite sheets and heat it until the resin preform is in a molten state to obtain molten graphite resin fiber material.

[0007] S02. Place the molten graphite resin fiber material from step S01 onto a mold and press it to obtain a composite bipolar plate.

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

[0009] The resin preform is prepared by heating a resin fiber prepreg to 120°C–200°C, and then rolling graphite slurry onto both sides of the resin fiber prepreg to obtain the resin preform. A layer of graphite slurry is coated onto the thermoplastic resin fiber prepreg by hot rolling. The purpose of hot rolling is mainly to soften the thermoplastic resin so that it can better bond with the graphite slurry.

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

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

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

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

[0014] The graphite slurry is an 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; the solvent is water.

[0015] The graphite sheet is graphite paper.

[0016] The heating temperature is 220℃~380℃.

[0017] The heating is achieved through a heating table.

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

[0019] The upper mold of the mold is at room temperature, and the lower mold is at half the melting temperature of the thermoplastic resin. The molten resin cools down and solidifies rapidly upon contact with the room-temperature upper mold, and is then quickly molded under the action of the punch press. The entire process, from the material leaving the heating table to the completion of molding, is controlled within 10 seconds.

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

[0021] On the other hand, this application embodiment also provides a composite material bipolar plate, which is prepared by the above-described preparation method.

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

[0023] This application addresses the problems of long manufacturing cycles and low production efficiency in current composite bipolar plates for fuel cells by improving both materials (such as the selection and proportioning of raw materials for bipolar plates) and processes (such as subsequent processing and the introduction of stamping technology). It provides a solution and technical support for the mass production of composite bipolar plates. The preparation method described in this application is simple and easy to implement, significantly shortening the bipolar plate preparation cycle and achieving high production efficiency, making it suitable for large-scale bipolar plate production. The resulting composite bipolar plates exhibit low contact resistance, high molding efficiency, and excellent performance, meeting the requirements for fuel cell applications. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0026] Currently, existing carbon fiber-graphite composite bipolar plates suffer from long preparation times and low production efficiency. To address these technical problems, this application provides a method for preparing a composite material bipolar plate, comprising the following steps:

[0027] S01. Place the resin preform between two graphite sheets and heat it until the resin preform is in a molten state to obtain molten graphite resin fiber material.

[0028] S02. Place the molten graphite resin fiber material from step S01 onto a mold and press it to obtain a composite bipolar plate.

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

[0030] The resin preform is prepared by the following method: heating the resin fiber prepreg to 120℃~200℃ (it can be 120℃, 150℃, 180℃, 200℃, etc., depending on actual needs), and then rolling graphite slurry onto 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; the resin fiber prepreg is a thermoplastic resin fiber prepreg.

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

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

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

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

[0036] The heating is achieved through a heating table.

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

[0038] The upper mold of the mold is at room temperature, and the lower mold is at half the melting temperature of the thermoplastic resin. The molten resin cools down and solidifies rapidly upon contact with the room-temperature upper mold, and is then quickly molded under the action of the punch press. The entire process, from the material leaving the heating table to the completion of molding, is controlled within 10 seconds.

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

[0040] On the other hand, this application embodiment also provides a composite material bipolar plate, which is prepared by the above-described preparation method.

[0041] This application addresses the problems of long manufacturing cycles and low production efficiency in current composite bipolar plates for fuel cells by improving both materials (such as the selection and proportioning of raw materials for bipolar plates) and processes (such as subsequent processing and the introduction of stamping technology). It provides a solution and technical support for the mass production of composite bipolar plates. The preparation method described in this application is simple and easy to implement, significantly shortening the bipolar plate preparation cycle and achieving high production efficiency, making it suitable for large-scale bipolar plate production. The resulting composite bipolar plates exhibit low contact resistance, high molding efficiency, and excellent performance, meeting the requirements for fuel cell applications.

[0042] Example 1

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

[0044] S01. Place the resin preform between two graphite sheets and heat it until the resin preform is in a molten state to obtain molten graphite resin fiber material.

[0045] S02. Place the molten graphite resin fiber material from step S01 onto a mold and press it to obtain a composite bipolar plate.

[0046] In step S01,

[0047] The resin preform is prepared by heating the resin fiber prepreg to 150°C, and then rolling graphite slurry onto 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; 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 prepreg.

[0052] The graphite slurry is an 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; the solvent is water. The graphite sheet is graphite paper with a thickness of 0.05 mm.

[0053] The heating temperature is 280°C, which melts the PPS and pre-compacts it. The heating is achieved through a heating table.

[0054] In step S02,

[0055] The upper mold of the mold is at room temperature, and the lower mold is at 140°C. The molten resin cools down and solidifies rapidly upon contact with the room-temperature upper mold, and is rapidly shaped under the action of the punch press. The time from when the material leaves the heating table to when it reaches the mold is controlled within 5 seconds, and the entire time from when the stamping is completed is controlled within 10 seconds.

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

[0057] The prepared composite bipolar plate was cut and then subjected to airtightness and related performance tests. The results showed that the airtightness of the composite bipolar plate was 0.2 sccm and the contact resistance was 6 mΩ·cm. 2 The electrical conductivity is 350 S / cm, meaning that the composite bipolar plate obtained in this application meets the requirements for use in fuel cells and can satisfy the needs of fuel cell use.

[0058] Example 2

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

[0060] S01. Place the resin preform between two graphite sheets and heat it until the resin preform is in a molten state to obtain molten graphite resin fiber material.

[0061] S02. Place the molten graphite resin fiber material from step S01 onto a mold and press it to obtain a composite bipolar plate.

[0062] In step S01,

[0063] The resin preform is prepared by heating the resin fiber prepreg to 150°C, and then rolling graphite slurry onto 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; 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 an 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; the solvent is water. The graphite sheet is graphite paper with a thickness of 0.08 mm.

[0069] The heating temperature is 220°C, which molten the PEEK and pre-compacts it. The heating is achieved through a heating table.

[0070] In step S02,

[0071] The upper mold of the mold is at room temperature, and the lower mold is at 110°C. The molten resin cools down and solidifies rapidly upon contact with the room-temperature upper mold, and is rapidly shaped under the action of the punch press. The time from when the material leaves the heating table to when it reaches the mold is controlled within 5 seconds, and the entire time from when the stamping is completed is controlled within 10 seconds.

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

[0073] The prepared composite bipolar plate was cut and then subjected to airtightness and related performance tests. The results showed that the airtightness of the composite bipolar plate was 0.19 sccm and the contact resistance was 6 mΩ·cm. 2 The electrical conductivity is 350 S / cm, meaning that the composite bipolar plate obtained in this application meets the requirements for use in fuel cells and can satisfy the needs of fuel cell use.

[0074] Example 3

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

[0076] S01. Place the resin preform between two graphite sheets and heat it until the resin preform is in a molten state to obtain molten graphite resin fiber material.

[0077] S02. Place the molten graphite resin fiber material from step S01 onto a mold and press it to obtain a composite bipolar plate.

[0078] In step S01,

[0079] The resin preform is prepared by heating the resin fiber prepreg to 150°C, and then rolling graphite slurry onto 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; 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 an 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; the solvent is water.

[0085] The graphite sheet is graphite paper with a thickness of 1 mm.

[0086] The heating temperature is 380°C, which molten the TPI and pre-compacts it. The heating is achieved through a heating table.

[0087] In step S02,

[0088] The upper mold of the mold is at room temperature, and the lower mold is at 190°C. The molten resin cools down and solidifies rapidly upon contact with the room-temperature upper mold, and is rapidly shaped under the action of the punch press. The time from when the material leaves the heating table to when it reaches the mold is controlled within 5 seconds, and the entire time from when the stamping is completed is controlled within 10 seconds.

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

[0090] The prepared composite bipolar plate was cut and then subjected to airtightness and related performance tests. The results showed that the airtightness of the composite bipolar plate was 0.18 sccm and the contact resistance was 6 mΩ·cm. 2 The electrical conductivity is 350 S / cm, meaning that the composite bipolar plate obtained in this application meets the requirements for use in fuel cells and can satisfy the needs of fuel cell use.

[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 within the protection scope of the present invention.

Claims

1. A method for preparing a composite material bipolar plate, characterized in that, Includes the following steps: S01. Place the resin preform between two graphite sheets and heat it until the resin preform is in a molten state to obtain molten graphite resin fiber material. S02. Place the molten graphite resin fiber material from step S01 onto a mold and press it to obtain a composite 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 graphite slurry onto both sides of the resin fiber prepreg to obtain the resin preform; The resin fiber prepreg is a thermoplastic resin fiber prepreg; In step S02, the temperature of the upper mold is room temperature, and the temperature of the lower mold is half the melting temperature of the thermoplastic resin. The stamping time is ≤10s.

2. The method for preparing the 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.

3. The method for preparing the 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 either T300 fiber or T700 fiber.

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

5. The method for preparing the composite material bipolar plate according to claim 1, characterized in that, The graphite slurry is an 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; the solvent is water.

6. The method for preparing the 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 the composite material bipolar plate according to claim 1, characterized in that, In step S01, the heating temperature is 220℃~380℃; the heating is achieved through a heating table.

8. The method for preparing the composite material bipolar plate according to claim 1, characterized in that, In step S02, the stamping is achieved by a stamping machine.

9. A composite material bipolar plate, characterized in that, The composite bipolar plate is prepared by the preparation method according to any one of claims 1 to 8.