Graphene treatment method of bipolar plate carbon-based coating, bipolar plate obtained through treatment and application

Abstract

The invention provides a graphene treatment method of a bipolar plate carbon-based coating, a bipolar plate obtained through treatment and application, and relates to the technical field of fuel cells. The graphene treatment method for the carbon-based coating of the bipolar plate comprises the following steps: firstly, providing the bipolar plate with the carbon-based coating, then treating the carbon-based coating by adopting a laser heat treatment technology, and converting part of a carbon-based material in the carbon-based coating into graphene under the instantaneous high-temperature action of laser to obtain a coating containing part of graphene. The treated coating contains part of graphene, and the graphene has very good electrical conductivity, thermal conductivity and corrosion resistance, so that the electrical conductivity, thermal conductivity and corrosion resistance of the bipolar plate subjected to graphene treatment are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a graphene treatment method for a carbon-based coating of a bipolar plate, a bipolar plate obtained by the graphene treatment, and applications thereof. Background Art

[0002] In order to balance the conductivity and corrosion resistance of the bipolar plate, the existing technology often uses chemical vapor deposition or physical vapor deposition to deposit a carbon-based coating on the metal bipolar plate. By using the sp2 and sp3 hybrid carbon materials contained in the carbon-based coating, the sp2 and sp3 ratios are adjusted to obtain an optimized carbon coating to balance the conductivity and corrosion resistance of the metal bipolar plate.

[0003] However, it is difficult to further improve the conductivity of the coating because of the sp3 component in the coating. At the same time, due to the presence of columnar crystals, the physical vapor deposition method is prone to plating points, and the gaps between carbon particles make it difficult to further improve the corrosion resistance of the coating. In addition, the amorphous carbon material in the carbon-based coating has weak bonding strength, large internal stress, and poor bonding strength with the transition layer. During long-term use, the coating is prone to partial peeling, shedding, and even large-scale powdering.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The first object of the present invention is to provide a graphene treatment method for a bipolar plate carbon-based coating, which can significantly improve the electrical conductivity, thermal conductivity and corrosion resistance of the bipolar plate.

[0006] The second object of the present invention is to provide a bipolar plate produced by the above-mentioned graphene treatment method of the bipolar plate carbon-based coating.

[0007] The third object of the present invention is to provide an application of a graphene treatment method for a bipolar plate carbon-based coating.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0009] The present invention provides a graphene treatment method for a bipolar plate carbon-based coating, the method comprising:

[0010] A bipolar plate with a carbon-based coating is provided, and then the carbon-based coating is treated by laser heat treatment technology to convert part of the carbon-based material in the carbon-based coating into graphene, thereby obtaining a coating containing part of the graphene.

[0011] The bipolar plate includes a metal bipolar plate, an engraved graphite plate or a molded graphite plate.

[0012] Furthermore, the carbon-based coating is a carbon-based coating obtained by chemical vapor deposition or physical vapor deposition;

[0013] The carbon-based coating contains at least one of amorphous carbon material, carbon black and worm graphite.

[0014] Furthermore, the carbon-based coating has a thickness of 30 nm to 5 μm.

[0015] Furthermore, the metal bipolar plate includes at least one of a stainless bipolar plate, a titanium-based bipolar plate, and an aluminum alloy bipolar plate.

[0016] Furthermore, the laser heat treatment technology used to treat the carbon-based coating is laser instantaneous high-temperature heat treatment;

[0017] The surface temperature of the material subjected to the instantaneous high temperature heat treatment by the laser is 400-1200°C, and the pulse time of the laser treatment is 10 -3 ~10 -7 Second.

[0018] Furthermore, the processing parameters of the laser instantaneous high temperature heat treatment at least meet at least one of the following:

[0019] The wavelength of the pulse laser is 500-1000nm, the laser pulse spot size is 0.1-0.4mm, the laser frequency is 30kHz-100kHz, and the laser energy is 10w / mm 2 ~500w / mm 2 .

[0020] Furthermore, the laser instantaneous high temperature heat treatment is carried out under a protective atmosphere;

[0021] Preferably, the protective atmosphere is nitrogen.

[0022] Furthermore, the graphene treatment method of the bipolar plate carbon-based coating also includes:

[0023] The step of locally performing laser heat treatment on the carbon-based coating of the bipolar plate to form different distributions of graphene content on the coating.

[0024] The present invention provides a bipolar plate made according to the above-mentioned graphene treatment method of the carbon-based coating of the bipolar plate;

[0025] The surface coating of the bipolar plate contains graphene material.

[0026] The present invention provides a graphene treatment method for the carbon-based coating of the bipolar plate, or the use of the bipolar plate in the preparation of a fuel cell.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention provides a graphene treatment method for a bipolar plate carbon-based coating. The method first provides a bipolar plate with a carbon-based coating, and then uses a laser heat treatment technology to treat the carbon-based coating. The instantaneous high temperature of the laser can convert part of the carbon-based material in the carbon-based coating into graphene to obtain a coating containing part of the graphene. Therefore, since the coating after the treatment of the present application contains part of the graphene, and the graphene itself has very good electrical conductivity, thermal conductivity and corrosion resistance, it can significantly improve the performance of the bipolar plate.

[0029] The bipolar plate provided by the present invention, which is prepared by the graphene treatment method of the bipolar plate carbon-based coating, can significantly improve the electrical conductivity, thermal conductivity and corrosion resistance of the metal bipolar plate because the surface coating of the bipolar plate contains graphene material.

[0030] The graphene treatment method of the bipolar plate carbon-based coating and the prepared bipolar plate provided by the present invention can be widely used in the preparation process of fuel cells. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than 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.

[0032] According to one aspect of the present invention, a graphene treatment method for a bipolar plate carbon-based coating comprises:

[0033] A bipolar plate with a carbon-based coating is provided, and then the carbon-based coating is treated by laser heat treatment technology to convert part of the carbon-based material in the carbon-based coating into graphene, thereby obtaining a coating containing part of the graphene.

[0034] The bipolar plate includes a metal bipolar plate, an engraved graphite plate or a molded graphite plate.

[0035] The present invention provides a graphene treatment method for a bipolar plate carbon-based coating. The method first provides a bipolar plate with a carbon-based coating, and then uses a laser heat treatment technology to treat the carbon-based coating. The instantaneous high temperature of the laser can convert part of the carbon-based material in the carbon-based coating into graphene to obtain a coating containing part of the graphene. Therefore, since the coating after the treatment of the present application contains part of the graphene, and the graphene itself has very good electrical conductivity, thermal conductivity and corrosion resistance, it can significantly improve the performance of the metal bipolar plate.

[0036] It should be noted that the present application uses laser heat treatment technology to perform subsequent treatment on the carbon-based coating. By selecting a suitable laser head (and controlling the pulse width, spot size, temperature and other parameters of the laser generator), the laser head is set to move along the guide rail in the horizontal or vertical direction to scan the bipolar plate or pre-coated strip to be treated, so that the laser can be evenly irradiated on the surface of the coating for continuous heat treatment.

[0037] The technical effects of the graphene treatment method of the bipolar plate carbon-based coating of the present application can also be summarized as follows:

[0038] (1) Under the high temperature of the laser, part of the carbon-based material in the carbon-based coating on the bipolar plate of the present application will be converted into graphene. These graphenes are mainly concentrated on the surface of the coating with the highest temperature, forming a graphene doping effect. The coating can effectively reduce the contact resistance during the contact process with the diffusion layer material, reduce the overall internal resistance of the single cell, and improve the battery performance.

[0039] Note: Graphene material itself has excellent corrosion resistance. Graphene covered on the surface of the coating can improve the electrochemical corrosion and gap corrosion between the carbon fiber in the carbon paper and the electrode coating.

[0040] Graphene has very good thermal conductivity. The thermal conductivity of pure, defect-free single-layer graphene is as high as 5300W / mK, which is the carbon material with the highest thermal conductivity so far, higher than single-walled carbon nanotubes (3500W / mK) and multi-walled carbon nanotubes (3000W / mK). When it is used as a carrier, the thermal conductivity can also reach 600W / mK. Therefore, the coating material treated by this application can improve the heat dissipation performance of the fuel cell, reduce the load of cooling water, reduce energy consumption, and improve the power generation performance of the stack.

[0041] (2) The graphene treatment method of the carbon-based coating of the bipolar plate of the present application can improve the defects of the carbon-based coating. Vacuum-deposited carbon coatings, especially physical vapor-deposited carbon-based coatings, have gaps between particles. The presence of these gaps will cause the hydrogen ions and fluorine ions in the water generated by the fuel cell to enter the transition layer and substrate through the gaps during use, corroding the substrate and transition layer and causing the coating to fall off. In addition, the columnar crystals, plating skips and defects in the carbon coating of vacuum deposition technology will form weak points in the coating, accelerating the peeling failure of the coating.

[0042] The present application adopts laser heat treatment technology to form graphene components that spread on the coating surface, which will inhibit the penetration of hydrogen ions into the interior. Its excellent corrosion resistance can prevent the corrosion of the coating. On the other hand, graphene has a certain expansion effect during the formation process, which has a plugging and repairing effect on the original gaps and through-columnar crystals, reducing the equivalent diameter of the gaps. According to the capillary effect, the smaller the equivalent diameter, the greater the force required when the liquid enters the capillary, so it can inhibit the penetration and destructive effect of hydrogen ions and fluoride ions in the generated water into the substrate.

[0043] (3) After the laser heat treatment of the present application, it is easy to release the internal stress generated during the preparation of the coating. By using laser heat treatment at high temperature, the compressive stress of physical vapor deposition and the tensile stress of chemical vapor deposition will be partially released at high temperature, reducing the risk of subsequent peeling failure of the coating during use. After heat treatment, the transition layer and the substrate will also form mutual penetration at high temperature, achieving molecular-level mutual dissolution and improving the bonding strength between the coating and the substrate. At the same time, high-temperature melting treatment of the transition layer can also reduce the gap in the transition layer, and even form a molten structure, reduce the porosity, and form a barrier layer.

[0044] In particular, since the laser heat treatment time is relatively short and the pulse width is in the millisecond level, the temperature inside the substrate is kept relatively low while the coating is being treated, which does not damage the crystal form of the material and has no effect on the hardness of the substrate, so that subsequent processing steps are not affected.

[0045] In a preferred embodiment of the present invention, the carbon-based coating is a carbon-based coating obtained by chemical vapor deposition or physical vapor deposition;

[0046] The carbon-based coating contains at least one of amorphous carbon material, carbon black and worm graphite.

[0047] Preferably, the carbon-based coating is an amorphous carbon coating or a graphite coating.

[0048] In a preferred embodiment of the present invention, the thickness of the carbon-based coating is 30 nm to 5 μm.

[0049] As a preferred embodiment, the thickness of the carbon-based coating is 100 nm to 1 μm.

[0050] In a preferred embodiment of the present invention, the metal bipolar plate includes at least one of a stainless steel bipolar plate, a titanium-based bipolar plate, and an aluminum alloy bipolar plate.

[0051] It should be noted that when the metal bipolar plate is a stainless steel-based bipolar plate, due to the large difference in physical properties between the stainless steel material and the carbon-based coating, a transition layer is usually deposited on the stainless steel surface. The transition layer material is usually made of titanium, chromium, and nickel metal materials. After the metal material is deposited, it is preferred to continue to deposit a metal carbide or metal nitride transition layer, and finally deposit a carbon-based coating on the surface.

[0052] This application uses laser heat treatment technology to treat the carbon-based coating, which can not only improve the bonding strength between the coating and the substrate and prevent the coating from falling off, but the heat treatment technology can also reduce the internal stress of the carbon-based coating and reduce the peeling or powdering of the coating; at the same time, the transition layer will partially melt under the action of laser heat treatment, and form a solid solution with the stainless steel substrate to form a co-permeation layer, further improving the bonding strength of the coating. The melting treatment of the transition layer also reduces the gap between particles, further inhibits the penetration of hydrogen ions and fluorine ions into the interior, and improves the corrosion resistance and life of the coating.

[0053] In a preferred embodiment of the present invention, the laser heat treatment technology used to treat the carbon-based coating is laser instantaneous high-temperature heat treatment;

[0054] The surface temperature of the material subjected to the instantaneous high temperature heat treatment by the laser is 400-1200°C, and the pulse time of the laser treatment is 10 -3 ~10 -7 Second.

[0055] As a preferred embodiment, the present application uses laser instantaneous high-temperature heat treatment to treat the carbon-based coating. By controlling the pulse width, spot size, temperature and other parameters of the laser generator, and carefully controlling the time the laser spot stays on the surface of the electrode plate, it is ensured that the coating surface can be heat treated without damaging the structure of the substrate itself, the crystal form and other material characteristics and mechanical properties.

[0056] It should be noted that due to the substrate, especially the stainless steel-based bipolar plates and their prefabricated coatings, the substrate's crystal form and mechanical properties and other material properties are easily changed at high temperatures. Therefore, the temperature control during the processing is very critical. It is necessary to perform high-temperature heat treatment on the coating, and to maintain the stability of the substrate and finely manage the process parameters. In addition, the thickness of the coating is usually relatively thin, generally only a few hundred nanometers to a dozen microns. If the high-temperature treatment time is too long, it will also cause the evaporation loss of the coating. Therefore, the temperature and treatment time of the coating must be precisely controlled.

[0057] In the above preferred embodiment, the processing parameters of the laser instantaneous high temperature heat treatment at least meet at least one of the following:

[0058] The wavelength of the pulse laser is 500-1000nm, the laser pulse spot size is 0.1-0.4mm, the laser frequency is 30kHz-100kHz, and the laser energy is 10w / mm 2 ~500w / mm 2 .

[0059] In the above preferred embodiment, the laser instantaneous high temperature heat treatment is carried out under a protective atmosphere;

[0060] Preferably, the protective atmosphere is nitrogen or argon.

[0061] As a preferred embodiment, in order to reduce the oxygen in the atmospheric environment combining with carbon at high temperature to form carbon-oxygen bonds during the heat treatment process, thereby reducing the conductivity of the coating, the heat treatment process is preferably carried out under a protective gas, using argon, nitrogen, etc. for protective heat treatment.

[0062] It is particularly preferred to use nitrogen as the protective gas for heat treatment. On the one hand, it can reduce the cost of coating treatment. On the other hand, at high temperature, part of the nitrogen will dissociate and combine with the dangling bonds in the carbon coating to form CN bonds, thereby avoiding the dangling bonds in the carbon coating combining with oxygen to form CO bonds during subsequent use to reduce the conductivity of the coating.

[0063] In a preferred embodiment of the present invention, the graphene treatment method of the metal bipolar plate carbon-based coating further comprises:

[0064] The step of locally performing laser heat treatment on the carbon-based coating of the metal bipolar plate to form different distributions of graphene content on the coating.

[0065] As a preferred embodiment, the present application can also use laser heat treatment to perform local treatment on the metal bipolar plate, forming different contents of graphene on the metal bipolar plate, improving the local material composition, bonding strength, and performance indicators of the bipolar plate, and achieving different functional requirements.

[0066] According to one aspect of the present invention, a bipolar plate is prepared according to the above-mentioned graphene treatment method of the carbon-based coating of the bipolar plate;

[0067] The surface coating of the bipolar plate contains graphene material.

[0068] The metal bipolar plate provided by the present invention, which is prepared by the graphene treatment method of the carbon-based coating of the bipolar plate, can significantly improve the electrical conductivity, thermal conductivity and corrosion resistance of the bipolar plate because the surface coating of the bipolar plate contains graphene material.

[0069] According to one aspect of the present invention, a graphene treatment method for the carbon-based coating of the bipolar plate described above, or the use of the bipolar plate described above in the preparation of a fuel cell.

[0070] The graphene treatment method of the bipolar plate carbon-based coating and the prepared bipolar plate provided by the present invention can be widely used in the preparation process of fuel cells.

[0071] The technical solution of the present invention will be further described below in conjunction with embodiments.

[0072] Example 1

[0073] A graphene treatment method for a carbon-based coating of a metal bipolar plate, the method comprising:

[0074] (1) 316L stainless steel was selected as the bare metal bipolar plate, and the substrate thickness was 0.1 mm. The bare bipolar plate was degreased, deoxidized, cleaned with pure water ultrasonic cleaning, and dried.

[0075] The bipolar plate was placed in the physical vapor deposition chamber and vacuumed to 8.5×10 -4 pa, introduce argon, adjust the vacuum degree to 0.7pa, turn on the magnetron titanium target, set the target current to 1A, the bias voltage to 800v, ​​and glow clean for 10min. Adjust the vacuum degree to 0.35pa, turn on the magnetron titanium target, set the target current to 20A, the bias voltage to 120v, and magnetron sputter for 15min. After sputtering, turn on the graphite target, set the target current to 15A, and deposit the titanium carbide transition layer for 5min. Turn off the titanium target, adjust the graphite target current to 30A, the bias power supply to 80V, turn on the ion source, set the ion source current to 5A, and continue deposition for 30min. Turn off the power after deposition, and take out the bipolar plate after cooling.

[0076] The interface was tested and found to have a titanium layer thickness of 110 nm, a titanium carbide layer thickness of 85 nm, and a graphite layer thickness of 130 nm.

[0077] (2) laser heat treatment is performed on the carbon-based material layer of the metal bipolar plate having the carbon-based coating in step (1), specifically:

[0078] Turn on the CO2 laser, set the laser spot to 0.4 mm, the pulse interval to 50 microseconds, adjust the laser power, and the spot energy to 15w / mm 2 After the setting is completed, the surface of the material is evenly irradiated. The surface temperature of the material subjected to the instantaneous high-temperature heat treatment by the laser is 800°C, and the laser treatment time is 300 seconds.

[0079] The laser instantaneous high temperature heat treatment is performed under a nitrogen protection atmosphere.

[0080] The laser treatment was performed twice to obtain a coating containing some graphene. After the treatment, the material was tested by Raman spectroscopy, and graphene peaks were detected in the treated samples.

[0081] Example 2

[0082] A method for graphene treatment of a carbon-based coating of a metal bipolar plate, the method being the same as Example 1 except that the thickness of the carbon-based coating in step (1) is 30 nm.

[0083] Example 3

[0084] A method for graphene treatment of a carbon-based coating of a metal bipolar plate, the method is the same as in Example 1 except that the pulse time of the laser treatment in step (2) is 30 milliseconds.

[0085] Example 4

[0086] A method for graphene treatment of a carbon-based coating of a metal bipolar plate, the method is the same as Example 1 except that the laser instantaneous high-temperature heat treatment in step (2) is not performed under a protective atmosphere.

[0087] Example 5

[0088] A method for graphene treatment of a carbon-based coating of a metal bipolar plate, the method is the same as Example 1 except that the laser instantaneous high-temperature heat treatment in step (2) is performed under an argon protective atmosphere.

[0089] Comparative Example 1

[0090] A graphene treatment method for a carbon-based coating of a metal bipolar plate, the method comprising:

[0091] (1) Same as Example 1;

[0092] (2) The carbon-based material layer of the metal bipolar plate with a carbon-based coating in step (1) is subjected to high-temperature treatment. The bipolar plate is placed in a muffle furnace, argon gas is introduced, and the heating rate is set to 5°C / min. The temperature is programmed to rise to 700°C and kept at this temperature for 10 minutes. After that, the plate is naturally cooled to room temperature and taken out.

[0093] Comparative Example 2

[0094] A graphene treatment method for a carbon-based coating of a metal bipolar plate, the method comprising:

[0095] (1) Same as Example 1;

[0096] (2) The carbon-based material layer of the metal bipolar plate with a carbon-based coating in step (1) is placed in a flash Joule furnace, heated to 700° C., the heating time is 2 minutes, the heat preservation time is 30 seconds, and then cooled and taken out. Flash Joule heat or rapid Joule heat technology treatment is performed to obtain a metal bipolar plate.

[0097] Comparative Example 3

[0098] A graphene treatment method for a carbon-based coating of a metal bipolar plate, the method comprising:

[0099] (1) Same as Example 1;

[0100] (2) The carbon-based material layer of the metal bipolar plate with a carbon-based coating in step (1) is subjected to electromagnetic induction heating treatment. Specifically, the electromagnetic heating current is set to 200A, the bipolar plate material is fixed with a clamp and placed in an electromagnetic induction coil, the electromagnetic induction heating time is 10s, and after induction heating, the bipolar plate is self-cooled in the air.

[0101] Experimental Example 1

[0102] In order to show that the metal bipolar plate obtained by the graphene treatment method of the carbon-based coating of the metal bipolar plate of the present application has better conductivity and corrosion resistance, the metal bipolar plates prepared in Examples 1 to 6 and Comparative Examples 1 to 3 are tested for contact resistance and corrosion, and the specific results are as follows:

[0103]

[0104] It can be seen from the above table that the carbon-based material layer of the metal bipolar plate of Example 1 of the present application has better conductivity and corrosion resistance after laser heat treatment;

[0105] However, after the metal bipolar plate of Example 2 with a carbon-based coating thickness of 30 nm was subjected to instantaneous high-temperature laser heat treatment, since the carbon-based coating was relatively thin, most of the carbon coating volatilized at high temperature during the laser treatment process, resulting in the thinning of the carbon coating, and even the exposure of the transition layer and the substrate in some areas. Therefore, the test index was too large.

[0106] The pulse time of the laser treatment in Example 3 is 30 milliseconds. Due to the long pulse time of the laser treatment, the laser stays on the coating surface for a long time, resulting in increased thermal evaporation of the carbon coating, increased micro-roughness and increased contact resistance of the diffusion layer carbon paper, and a slight increase in the overall performance indicators.

[0107] Example 4 Since the laser instantaneous high-temperature heat treatment is not carried out under a protective atmosphere, under the action of the laser high temperature, the dangling bonds of the amorphous carbon material will react with oxygen to form CO bonds. The formation of carbon-oxygen bonds will cause an increase in the contact resistance of the coating.

[0108] In Example 5, since the laser instantaneous high-temperature heat treatment is carried out in an argon protective atmosphere, the coating is laser heat treated at high temperature, and the coating is better protected to avoid the formation of CO bonds, resulting in a relatively low contact resistance of the coating.

[0109] Comparative Example 1 adopts conventional high-temperature heat treatment, which will damage the structure of the substrate itself. Compared with the instantaneous high-temperature laser treatment in Example 1 of the present application, the mechanical and other properties of the material are poor.

[0110] Comparative Example 2 uses flash Joule heating or rapid Joule heating technology to replace the instantaneous high temperature treatment method of the laser in the present application. Since the converted graphene is not on the surface of the coating, the performance is worse than that of the present application, and the bonding of the transition layer is also poor.

[0111] Comparative Example 3 uses electromagnetic induction heating to treat the carbon-based coating. Compared with the instantaneous high-temperature laser treatment of the present application, the bonding of the transition layer is also poor.

[0112] Example 6

[0113] A graphene treatment method for a carbon-based coating of a graphite bipolar plate, the method comprising:

[0114] (1) Select engraved graphite plate as the bare bipolar plate;

[0115] (2) laser heat treatment is performed on the carbon-based material layer of the bipolar plate having the carbon-based coating in step (1), specifically:

[0116] Turn on the CO2 laser, set the laser spot to 0.4 mm, the pulse interval to 50 microseconds, adjust the laser power, and the spot energy to 15w / mm 2 After the setting is completed, the surface of the material is evenly irradiated. The surface temperature of the material subjected to the instantaneous high-temperature heat treatment by the laser is 800°C, and the laser treatment time is 300 seconds.

[0117] The laser instantaneous high temperature heat treatment is performed under a nitrogen protection atmosphere.

[0118] The laser treatment was performed twice to obtain a coating containing some graphene. After the treatment, the material was tested by Raman spectroscopy, and graphene peaks were detected in the treated samples.

[0119] The conductivity and corrosion resistance test results of this embodiment are as follows:

[0120] Contact resistance 1.8@0.6MPa;

[0121] The test results of the control without laser heat treatment in step (2) of this embodiment are as follows: contact resistance 2.5@0.6MPa. Therefore, preferably, the engraved graphite plate and the molded graphite plate are laser treated to obtain part of the graphene component. Nitrogen is preferably used as an inert gas during the laser treatment process, and part of the carbon forms a CN bond with nitrogen. The presence of the CN bond can prevent the subsequent bipolar plate from forming CO with oxygen in the fuel during use, causing an increase in contact resistance.

[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A graphene treatment method for a bipolar plate carbon-based coating, characterized in that: The method comprises: Providing a bipolar plate with a carbon-based coating, and then heat-treating the carbon-based coating using a laser heat treatment technique to convert a portion of the carbon-based material in the carbon-based coating into graphene, thereby obtaining a coating containing a portion of graphene; The bipolar plate includes a metal bipolar plate, an engraved graphite plate or a molded graphite plate.

2. The graphene treatment method of the bipolar plate carbon-based coating according to claim 1, characterized in that: The carbon-based coating is a carbon-based coating obtained by chemical vapor deposition or physical vapor deposition; The carbon-based coating contains at least one of amorphous carbon material, carbon black and worm graphite.

3. The graphene treatment method of the bipolar plate carbon-based coating according to claim 1, characterized in that: The thickness of the carbon-based coating is 30 nm to 5 μm.

4. The graphene treatment method of the bipolar plate carbon-based coating according to claim 1, characterized in that: The metal bipolar plate includes at least one of a stainless steel bipolar plate, a titanium bipolar plate, and an aluminum alloy bipolar plate.

5. The graphene treatment method of the bipolar plate carbon-based coating according to claim 1, characterized in that: The heat treatment of the carbon-based coating by using laser heat treatment technology is laser instantaneous high-temperature heat treatment; The surface temperature of the material subjected to the instantaneous high temperature heat treatment by the laser is 400-1200°C, and the pulse time of the laser treatment is 10 -3 ~10 -7 Second.

6. The graphene treatment method for the bipolar plate carbon-based coating according to claim 5, characterized in that: The processing parameters of the laser instantaneous high temperature heat treatment at least meet at least one of the following: The wavelength of the pulse laser is 500-1000nm, the laser pulse spot size is 0.1-0.4mm, the laser frequency is 30kHz-100kHz, and the laser energy is 10w / mm 2 ~500w / mm 2 .

7. The graphene treatment method for a bipolar plate carbon-based coating according to claim 5, characterized in that: The laser instantaneous high temperature heat treatment is carried out in a protective atmosphere; Preferably, the protective atmosphere is nitrogen.

8. The graphene treatment method for a bipolar plate carbon-based coating according to claim 1, characterized in that: The graphene treatment method of the bipolar plate carbon-based coating also includes: The step of locally performing laser heat treatment on the carbon-based coating of the bipolar plate to form different distributions of graphene content on the coating.

9. A bipolar plate made by the graphene treatment method of a bipolar plate carbon-based coating according to any one of claims 1 to 8; The surface coating of the bipolar plate contains graphene material.

10. A method for graphene treatment of a carbon-based coating of a bipolar plate according to any one of claims 1 to 8, or use of the bipolar plate according to claim 9 in the preparation of a fuel cell.

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