Hydrogen fuel cell metal pole plate coating as well as preparation method and application thereof

Abstract

The invention discloses a hydrogen fuel cell metal pole plate coating and a preparation method and application thereof. The preparation method of the hydrogen fuel cell metal polar plate coating comprises the following steps: taking out a hydrogen fuel cell metal bipolar plate at room temperature, baking, stopping heating, and naturally cooling to room temperature. Molecules or atoms in the film layer can be rearranged through high temperature in the baking process, and a more compact structure is formed; the rearrangement can reduce the porosity and increase the density of the film layer, thereby preventing the weak acid liquid and fluorine ions of the hydrogen fuel cell from reaching the surface of the metal base material through the film layer to cause corrosion of the base material.

Description

Technical Field

[0001] The invention relates to a hydrogen fuel cell metal plate coating and a preparation method and application thereof, belonging to the technical field of batteries. Background Art

[0002] A hydrogen fuel cell is a device that converts hydrogen and oxygen directly into electrical energy through a chemical reaction. Currently, there are graphite plate hydrogen fuel cells and metal plate hydrogen fuel cells. One of the core components of a metal plate hydrogen fuel cell is a metal bipolar plate. Metal bipolar plates play a vital role in fuel cells, including supporting the membrane electrode structure, separating hydrogen and oxygen, collecting electrons, conducting heat, providing gas channels, discharging water generated by the reaction, and bearing assembly preload.

[0003] Metal bipolar plates need to have good electrical conductivity, corrosion resistance, high mechanical strength and light weight. During the manufacturing process, the main challenges faced by metal bipolar plates are strong corrosion resistance and high production efficiency. The materials of metal bipolar plates mainly include stainless steel, aluminum and titanium alloys, among which stainless steel is widely used due to its good electrical conductivity and processing performance. In terms of production process, the manufacturing process of metal bipolar plates includes steps such as strip selection, forming and splitting, and coating treatment.

[0004] The corrosion resistance of metal bipolar plate coating is the focus of research. The coating of metal bipolar plate mainly includes conductive polymer composite materials, precious metal surface modification materials, nitrogen doped or carbon-based alloy materials, etc.

[0005] The corrosion of metal bipolar plates mainly comes from stress corrosion, chemical corrosion and electrochemical corrosion, and coating is needed to improve the performance of the substrate. The current main process is PVD (physical vapor deposition), which consists of a base layer and an outer conductive corrosion-resistant layer. The base layer is a metal nitride coating: such as TiN, CrN, NbN, etc. Metal carbide coating: such as TiC; the conductive corrosion-resistant layer is mainly an amorphous carbon coating, which has both a carbon film coating and a small amount of precious metal coating such as Au, Pt, etc., which can effectively reduce the defects of the coating and improve the corrosion resistance of the plate.

[0006] The current PVD coating has low sputtering temperature, basically between 100-400°C, short sputtering time, and relatively thin film layer between 0.05-1 micron, resulting in poor density and corrosion resistance. Summary of the invention

[0007] In view of this, the present invention provides a hydrogen fuel cell metal plate coating and a preparation method and application thereof. The technical problem to be solved is that the high temperature during the baking process can rearrange the molecules or atoms in the film layer, increase the density of the film layer, and thereby prevent the weak acidic liquid and fluoride ions of the hydrogen fuel cell from passing through the film layer to reach the surface of the metal substrate and cause corrosion of the substrate.

[0008] The purpose of the present invention and the technical problem to be solved are achieved by adopting the following technical solutions. A method for preparing a metal plate coating of a hydrogen fuel cell proposed by the present invention comprises the following steps:

[0009] After the hydrogen fuel cell metal bipolar plate is taken out from room temperature, it is baked, and then the heating is stopped and the plate is naturally cooled to room temperature.

[0010] The purpose of the present invention and the technical problems to be solved can be further achieved by adopting the following technical measures.

[0011] Preferably, in the aforementioned method for preparing the hydrogen fuel cell metal plate coating, during the baking, the plates of the hydrogen fuel cell metal bipolar plate do not contact each other, and the distance between the plates is 1-5 cm.

[0012] Preferably, in the aforementioned method for preparing the metal plate coating of a hydrogen fuel cell, the baking conditions are as follows: heating to 150-250° C. for 1-3 hours, and the baking time is more than 10 hours.

[0013] The purpose of the present invention and the solution of its technical problems can also be achieved by the following technical measures: A hydrogen fuel cell metal plate coating proposed by the present invention comprises two metal plate substrates, on which a PVD primer layer and a conductive anti-corrosion layer connected in sequence are arranged.

[0014] The purpose of the present invention and the technical problems to be solved can be further achieved by adopting the following technical measures.

[0015] Preferably, in the aforementioned hydrogen fuel cell metal plate coating, the PVD base layer is composed of a plurality of closely arranged base layer film atoms; and the conductive anti-corrosion layer is composed of a plurality of closely arranged anti-corrosion layer film atoms.

[0016] Preferably, in the aforementioned hydrogen fuel cell metal plate coating, the PVD primer layer is a Ti layer, a TiN layer, a Cr layer or a TiC layer, and its thickness is 0.09-0.11 μm.

[0017] Preferably, in the aforementioned hydrogen fuel cell metal plate coating, the conductive anti-corrosion layer is a carbon layer or an Au layer, and its thickness is 57-63 nm.

[0018] Preferably, the aforementioned hydrogen fuel cell metal polar plate coating, wherein the hydrogen fuel cell metal bipolar plate coating is prepared by the above-mentioned method.

[0019] The purpose of the present invention and the technical problems solved therein can also be achieved by adopting the following technical measures: The present invention proposes an application of a hydrogen fuel cell metal plate coating in improving the corrosion resistance of a hydrogen fuel cell metal bipolar plate.

[0020] Compared with the prior art, the hydrogen fuel cell metal plate coating and its preparation method and application described in the present invention have the following beneficial effects:

[0021] The high temperature during the baking process can rearrange the molecules or atoms in the film layer to form a more compact structure; the rearrangement can reduce the porosity and increase the density of the film layer, thereby preventing the weak acidic liquid and fluoride ions of the hydrogen fuel cell from passing through the film layer to reach the surface of the metal substrate and causing corrosion of the substrate.

[0022] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the metal plate coating of a hydrogen fuel cell in the prior art;

[0024] Figure 2 Schematic diagram of the structure of the metal plate coating of a hydrogen fuel cell according to some embodiments of the present invention. DETAILED DESCRIPTION

[0025] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of a hydrogen fuel cell metal plate coating and its preparation method and its specific implementation method, structure, characteristics and effects of the application proposed by the present invention in combination with the preferred embodiment. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0026] Unless otherwise specified, the materials, reagents, etc. involved below are all commercially available products well known to those skilled in the art; unless otherwise specified, the methods described are all methods known in the art. Unless otherwise defined, the technical terms or scientific terms used should have the usual meanings understood by ordinary technicians in the field to which the present invention belongs. If no specific experimental steps or conditions are specified below, the operations or conditions of the conventional experimental steps described in the literature in the field can be followed.

[0027] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0028] The goal set by the U.S. Department of Energy (DOE) is that the cathode corrosion current density should be less than 1 μA cm -2 , which indicates that under cathodic conditions, the corrosion rate of the metal plate is very low, providing good durability.

[0029] Some embodiments of the present invention provide a method for preparing a metal plate coating of a hydrogen fuel cell, comprising the following steps:

[0030] 1) The hydrogen fuel cell metal bipolar plate is taken out from the PVD furnace at room temperature and placed in an oven;

[0031] 2) The hydrogen fuel cell metal bipolar plate is vertically suspended in a sample basket, the plates do not touch each other, and the spacing is 1-5 cm to ensure uniform heating; the sample basket is a rectangular stainless steel sampling basket with a size of 400mm*300mm*100mm, an open top, and handles on both sides; the stainless steel sampling basket is made of national standard stainless steel wire through plain weave, with a wire diameter of 1mm and a hole diameter of 6mm; if the spacing between the plates is less than 1cm, the drying effect is poor; if the spacing between the plates is greater than 5cm, the baking efficiency is reduced;

[0032] 3) Heat the oven to 150-250℃ for 1-3h, keep it warm for more than 10 hours, then stop heating and cool it down to room temperature naturally. If the oven heating time is less than 1h, the metal bipolar plate may be deformed due to too fast drying; if the oven heating time is more than 3h, the drying is too slow, which reduces the baking efficiency; if the heating temperature is less than 150℃, the baking efficiency is reduced due to low temperature; if the heating temperature is greater than 250℃, the metal bipolar plate may be deformed due to too high temperature; if the insulation time is less than 10 hours, the density of the metal bipolar plate coating will deteriorate.

[0033] Some embodiments of the present invention also provide a hydrogen fuel cell metal plate coating, wherein the hydrogen fuel cell metal plate coating is prepared by the above method. Figure 2 As shown, the hydrogen fuel cell metal bipolar plate coating includes a metal plate substrate 1, on which a PVD base layer 2 and a conductive anti-corrosion layer 3 are sequentially connected; the PVD base layer 2 is composed of a plurality of closely arranged base layer film atoms; the conductive anti-corrosion layer 3 is composed of a plurality of closely arranged anti-corrosion layer film atoms. Figure 1 The structure diagram of the metal plate coating of the hydrogen fuel cell in the prior art is shown in FIG. Figure 1It can be seen that the existing hydrogen fuel cell metal bipolar plate coating includes two metal plate substrates 1', and the two metal plate substrates 1' are provided with a base layer 2' and a conductive anti-corrosion layer 3' connected in sequence; the base layer 2' is composed of a plurality of loosely arranged base layer film layer atoms; the conductive anti-corrosion layer 3' is composed of a plurality of loosely arranged anti-corrosion layer film layer atoms.

[0034] Furthermore, the PVD base layer 2 may be a Ti layer, a TiN layer, a Cr layer or a TiC layer, and its thickness is 0.09-0.11 μm.

[0035] Furthermore, the conductive anti-corrosion layer 3 may be a carbon layer or an Au layer, and the thickness thereof is 57-63 nm.

[0036] Some embodiments of the present invention also provide an application of a hydrogen fuel cell metal plate coating in improving the corrosion resistance of a hydrogen fuel cell metal bipolar plate.

[0037] The cathode corrosion current density of the plate is tested in accordance with GB / T 20042.6-2024 "Proton Exchange Membrane Fuel Cell Part 6: Bipolar Plate Characteristics Test Method".

[0038] The present invention is further described below in conjunction with specific embodiments.

[0039] Example 1

[0040] This embodiment provides a method for preparing a metal plate coating of a hydrogen fuel cell, comprising the following steps:

[0041] (1) Hydrogen fuel cell metal plate PVD base layer - Ti layer, thickness 0.1μm, anti-corrosion coating - carbon layer 60nm, 3 plates;

[0042] (2) Place the above-mentioned electrode plates in an oven and hang them vertically in a sample basket with a plate spacing of 3 cm to ensure uniform heating and prevent scratches on the film layer; the sample basket is a rectangular stainless steel sampling basket with a size of 400mm*300mm*100mm, an open top and handles on both sides; the stainless steel sampling basket is made of national standard stainless steel wire through plain weave, with a wire diameter of 1mm and a hole diameter of 6mm;

[0043] (3) Open the oven, evenly raise the temperature to 150° C. for 1 hour, keep the temperature for 10 hours, and then naturally cool to room temperature to obtain the hydrogen fuel cell metal bipolar plate coating.

[0044] The cathode corrosion current density of the above-mentioned hydrogen fuel cell metal plate was tested in accordance with GB / T 20042.6-2024 "Proton Exchange Membrane Fuel Cell Part 6: Bipolar Plate Characteristics Test Method". The specific results are shown in Table 1.

[0045] Example 2

[0046] This embodiment provides a method for preparing a metal plate coating of a hydrogen fuel cell, comprising the following steps:

[0047] (1) Hydrogen fuel cell metal plate PVD base layer - TiN layer, thickness is 0.1μm, anti-corrosion coating - carbon layer is 60nm, 3 plates;

[0048] (2) Place the above-mentioned electrode plates in an oven and hang them vertically in a sample basket with a plate spacing of 3 cm to ensure uniform heating and prevent scratches on the film layer; the sample basket is a rectangular stainless steel sampling basket with a size of 400mm*300mm*100mm, an open top and handles on both sides; the stainless steel sampling basket is made of national standard stainless steel wire through plain weave, with a wire diameter of 1mm and a hole diameter of 6mm;

[0049] (3) Open the oven, evenly raise the temperature to 200° C. for 2 h, keep the temperature for 13 h, and then naturally cool to room temperature to obtain the hydrogen fuel cell metal bipolar plate coating.

[0050] The cathode corrosion current density of the above-mentioned hydrogen fuel cell metal plate was tested in accordance with GB / T 20042.6-2024 "Proton Exchange Membrane Fuel Cell Part 6: Bipolar Plate Characteristics Test Method". The specific results are shown in Table 1.

[0051] Example 3

[0052] This embodiment provides a method for preparing a metal plate coating of a hydrogen fuel cell, comprising the following steps:

[0053] (1) Hydrogen fuel cell metal plate PVD base layer - Cr layer, thickness is 0.1μm, anti-corrosion coating - Au layer is 60nm, 3 plates;

[0054] (2) Place the above-mentioned electrode plates in an oven and hang them vertically in a sample basket with a plate spacing of 4 cm to ensure uniform heating and prevent scratches on the film layer; the sample basket is a rectangular stainless steel sampling basket with a size of 400 mm*300 mm*100 mm, an open top and handles on both sides; the stainless steel sampling basket is made of national standard stainless steel wire through plain weave, with a wire diameter of 1 mm and a hole diameter of 6 mm;

[0055] (3) Open the oven, evenly raise the temperature to 220° C. for 2 h, keep the temperature for 15 h, and then naturally cool to room temperature to obtain the hydrogen fuel cell metal bipolar plate coating.

[0056] The cathode corrosion current density of the above-mentioned hydrogen fuel cell metal plate was tested in accordance with GB / T 20042.6-2024 "Proton Exchange Membrane Fuel Cell Part 6: Bipolar Plate Characteristics Test Method". The specific results are shown in Table 1.

[0057] Example 4

[0058] This embodiment provides a method for preparing a metal plate coating of a hydrogen fuel cell, comprising the following steps:

[0059] (1) Hydrogen fuel cell metal plate PVD base layer - TiC layer, thickness is 0.1μm, anti-corrosion coating - carbon layer is 60nm, 3 plates;

[0060] (2) Place the above-mentioned electrode plates in an oven and hang them vertically in a sample basket with a spacing of 5 cm between the plates to ensure uniform heating and prevent scratches on the film layer; the sample basket is a rectangular stainless steel sampling basket with a size of 400 mm*300 mm*100 mm, an open top and handles on both sides; the stainless steel sampling basket is made of national standard stainless steel wire through plain weave, with a wire diameter of 1 mm and a hole diameter of 6 mm;

[0061] (3) Open the oven, evenly raise the temperature to 250° C. for 3 h, keep the temperature for 20 h, and then naturally cool to room temperature to obtain the hydrogen fuel cell metal bipolar plate coating.

[0062] The cathode corrosion current density of the above-mentioned hydrogen fuel cell metal plate was tested in accordance with GB / T 20042.6-2024 "Proton Exchange Membrane Fuel Cell Part 6: Bipolar Plate Characteristics Test Method". The specific results are shown in Table 1.

[0063] Comparative Example 1

[0064] This comparative example provides a method for preparing a metal plate coating of a hydrogen fuel cell, comprising the following steps:

[0065] (1) Hydrogen fuel cell metal plate PVD base layer - Ti layer, thickness 0.1μm, anti-corrosion coating - carbon layer 60nm, 3 plates;

[0066] (2) Open the oven, evenly raise the temperature to 150° C. for 1 hour, keep the temperature for 10 hours, and then naturally cool to room temperature to obtain the hydrogen fuel cell metal bipolar plate coating.

[0067] The cathode corrosion current density of the metal plate of the above hydrogen fuel cell was tested in accordance with GB / T 20042.6-2024 "Proton Exchange Membrane Fuel Cell Part 6: Bipolar Plate Characteristics Test Method". The specific results are shown in Table 2.

[0068] Comparative Example 2

[0069] This comparative example provides a method for preparing a metal plate coating of a hydrogen fuel cell, comprising the following steps:

[0070] (1) Hydrogen fuel cell metal plate PVD base layer - TiN layer, thickness is 0.1μm, anti-corrosion coating - carbon layer is 60nm, 3 plates;

[0071] (2) Open the oven, evenly raise the temperature to 200° C. for 2 h, keep the temperature for 13 h, and then naturally cool to room temperature to obtain the hydrogen fuel cell metal bipolar plate coating.

[0072] The cathode corrosion current density of the metal plate of the above hydrogen fuel cell was tested in accordance with GB / T 20042.6-2024 "Proton Exchange Membrane Fuel Cell Part 6: Bipolar Plate Characteristics Test Method". The specific results are shown in Table 2.

[0073] Comparative Example 3

[0074] This comparative example provides a method for preparing a metal plate coating of a hydrogen fuel cell, comprising the following steps:

[0075] (1) Hydrogen fuel cell metal plate PVD base layer - Cr layer, thickness is 0.1μm, anti-corrosion coating - Au layer is 60nm, 3 plates;

[0076] (2) Open the oven, evenly raise the temperature to 220° C. for 2 h, keep the temperature for 15 h, and then naturally cool to room temperature to obtain the hydrogen fuel cell metal bipolar plate coating.

[0077] The cathode corrosion current density of the metal plate of the above hydrogen fuel cell was tested in accordance with GB / T 20042.6-2024 "Proton Exchange Membrane Fuel Cell Part 6: Bipolar Plate Characteristics Test Method". The specific results are shown in Table 2.

[0078] Comparative Example 4

[0079] This comparative example provides a method for preparing a metal plate coating of a hydrogen fuel cell, comprising the following steps:

[0080] (1) Hydrogen fuel cell metal plate PVD base layer - TiC layer, thickness is 0.1μm, anti-corrosion coating - carbon layer is 60nm, 3 plates;

[0081] (2) Open the oven, evenly raise the temperature to 250° C. for 3 h, keep the temperature for 20 h, and then naturally cool to room temperature to obtain the hydrogen fuel cell metal bipolar plate coating.

[0082] The cathode corrosion current density of the metal plate of the above hydrogen fuel cell was tested in accordance with GB / T 20042.6-2024 "Proton Exchange Membrane Fuel Cell Part 6: Bipolar Plate Characteristics Test Method". The specific results are shown in Table 2.

[0083] Table 1 Corrosion rate test table of hydrogen fuel cell metal plates of Examples 1-4

[0084]

[0085] Table 2 Corrosion rate test table of hydrogen fuel cell metal plates of comparative examples 1-4

[0086]

[0087] It can be seen from the data in Tables 1 and 2 that, compared with Comparative Examples 1-4, Examples 1-4 of the present invention can greatly improve the corrosion resistance of the metal plates of hydrogen fuel cells and greatly improve the battery life. The cathode corrosion current density of the plates of Examples 1-4 of the present invention is 0.16 μA·cm -2 ~0.31μA·cm -2 .

[0088] The above embodiments are only used to explain the content of the present invention, and are not intended to limit the present invention. Simple technical variations within the technical concept of the present invention should be considered to be covered by the content disclosed by the present invention and belong to the protection scope of the present invention.

[0089] In the specification of the present invention, a lot of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some embodiments, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this specification.

[0090] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0091] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

[0092] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a metal plate coating for a hydrogen fuel cell, characterized in that: The following steps are involved: After the hydrogen fuel cell metal bipolar plate is taken out from room temperature, it is baked, and then the heating is stopped and the plate is naturally cooled to room temperature.

2. The method for preparing a hydrogen fuel cell metal plate coating according to claim 1, characterized in that: During the baking, the plates of the hydrogen fuel cell metal bipolar plates do not contact each other, and the distance between them is 1-5 cm.

3. The method for preparing a metal plate coating for a hydrogen fuel cell according to claim 1, characterized in that: The baking temperature is increased to 150-250° C. from 1-3 h.

4. The method for preparing a metal plate coating for a hydrogen fuel cell according to claim 1, characterized in that: The baking time is more than 10 hours.

5. A hydrogen fuel cell metal plate coating, characterized in that: The hydrogen fuel cell metal plate coating comprises a metal plate substrate, on which a PVD primer layer and a conductive anti-corrosion layer are sequentially connected.

6. The hydrogen fuel cell metal plate coating according to claim 5, characterized in that: The PVD base layer is composed of a plurality of closely arranged base layer film atoms; the conductive anti-corrosion layer is composed of a plurality of closely arranged anti-corrosion layer film atoms.

7. The hydrogen fuel cell metal plate coating according to claim 6, characterized in that: The PVD base layer is a Ti layer, a TiN layer, a Cr layer or a TiC layer, and its thickness is 0.09-0.11 μm.

8. The hydrogen fuel cell metal plate coating according to claim 6, characterized in that: The conductive anti-corrosion layer is a carbon layer or an Au layer, and its thickness is 57-63nm.

9. The hydrogen fuel cell metal plate coating according to claim 5, characterized in that: The hydrogen fuel cell metal plate coating is prepared by the method according to any one of claims 1 to 4.

10. Use of the hydrogen fuel cell metal plate coating according to any one of claims 5 to 9 in improving the corrosion resistance of hydrogen fuel cell metal bipolar plates.

Images