Treatment method of titanium bipolar plate of hydrogen fuel cell and titanium bipolar plate

Abstract

The invention belongs to the technical field of hydrogen fuel cells, discloses a treatment method of a titanium bipolar plate of a hydrogen fuel cell and the titanium bipolar plate, and aims to solve the problem of poor durability of the titanium bipolar plate caused by unstable or fluctuating working conditions of a fuel cell in a hydrogen-electricity coupling system. The treatment method comprises the following steps: pretreating the titanium bipolar plate to remove impurities and an oxidation film on the surface of the titanium bipolar plate; carrying out nitriding treatment on the pretreated titanium bipolar plate; carrying out acid leaching treatment on the titanium bipolar plate subjected to nitriding treatment to form a passivation layer; and carrying out carburizing treatment on the titanium bipolar plate subjected to acid leaching treatment. A nitriding-acid leaching-carburizing three-stage synergistic mechanism is provided, a gradient functionalized protection system is constructed on the surface of the titanium bipolar plate, the nitriding layer provides basic corrosion resistance, the acid leaching layer guarantees compactness, the carburizing layer guarantees conductivity, and the contradictory problem of durability and conductivity under the fluctuating working condition is solved through synergism of the nitriding layer, the acid leaching layer and the carburizing layer.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen fuel cells, and particularly relates to a treatment method for a titanium bipolar plate of a hydrogen fuel cell and a titanium bipolar plate. Background Art

[0002] As an efficient and clean energy conversion device, the proton exchange membrane fuel cell (PEMFC) plays a key role in the hydrogen-electricity coupling system. It directly converts the chemical energy of hydrogen into electrical energy through an electrochemical reaction, while generating by-product heat energy. It has advantages such as high energy conversion efficiency and zero carbon emissions, so it has broad application prospects in the fields of renewable energy integration, microgrid power supply, and transportation power.

[0003] In a hydrogen fuel cell, the bipolar plate (BPP) is one of the core components, undertaking multiple functions such as conductive series connection, gas distribution, heat dissipation, and structural support. Among them, the titanium bipolar plate has gradually become an important alternative to traditional graphite bipolar plates due to its light weight, high strength, and excellent corrosion resistance. However, in the strongly acidic (pH 2-3) and oxidation-reduction alternating environment of the fuel cell, an insulating oxide film (TiO2) is easily formed on the surface of titanium metal, resulting in an increase in contact resistance and affecting the battery efficiency; at the same time, in the hydrogen-electricity coupling system, due to the intermittency of renewable energy such as wind energy and solar energy, the fuel cell needs to be frequently started and stopped to adapt to fluctuating working conditions, which further exacerbates the corrosion and performance degradation problems of the titanium bipolar plate.

[0004] At present, in order to improve the stability and conductivity of the titanium bipolar plate, the industry generally adopts surface modification technologies such as nitriding treatment to generate a titanium nitride (TiN) coating on the surface of titanium to enhance corrosion resistance. However, the single nitriding treatment technology has obvious limitations: one is the poor coating uniformity. The too-fast growth rate of TiN during the nitriding process is likely to cause stacking or insufficient local coverage, affecting the protection effect; the other is the limited improvement in conductivity. Although TiN has certain conductivity, it is still difficult to completely offset the high resistance effect of the surface oxide film; the third is the poor adaptability to fluctuating working conditions. Under the stress of frequent start and stop, the single coating is prone to peeling or generating microcracks, accelerating performance degradation. Summary of the Invention

[0005] Based on the above-mentioned disadvantages and deficiencies existing in the prior art, one of the purposes of the present invention is to at least solve one or more of the above problems existing in the prior art. In other words, one of the purposes of the present invention is to provide a treatment method for a titanium bipolar plate of a hydrogen fuel cell and a titanium bipolar plate that meet one or more of the foregoing requirements, so as to solve the problem of poor durability of the titanium bipolar plate due to unstable or fluctuating working conditions in the hydrogen-electricity coupling system of the fuel cell.

[0006] In order to achieve the above-mentioned invention purpose, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a method for treating a titanium bipolar plate of a hydrogen fuel cell. The titanium bipolar plate is a titanium metal bipolar plate or a titanium alloy bipolar plate. The treatment method includes the steps of: S1. Pretreating the titanium bipolar plate to remove impurities and oxide films on its surface; S2. Nitriding the pretreated titanium bipolar plate; S3. Acid pickling the nitrided titanium bipolar plate to form a passivation layer; S4. Carburizing the acid-pickled titanium bipolar plate.

[0007] As a preferred solution, the pretreatment in step S1 is specifically: surface grinding, ultrasonic cleaning, and drying of the titanium bipolar plate for standby; the ultrasonic cleaning is carried out in acetone or hydrochloric acid or deionized water or absolute ethanol.

[0008] As a preferred solution, the nitriding treatment in step S2 adopts a plasma nitriding process or a thermochemical treatment nitriding process. The specific steps of adopting the plasma nitriding process include: placing the titanium bipolar plate in a plasma nitriding furnace, evacuating, replacing with argon, turning on the voltage, and introducing a nitriding gas and then heating up to carry out nitriding treatment.

[0009] As a preferred solution, the process parameters of the nitriding treatment are: the voltage range is set to [600V, 700V]; the nitriding temperature range is set to [750°C, 850°C]; the nitriding time range is set to [6h, 10h]; the internal pressure of the plasma nitriding furnace is set to [200Pa, 250Pa].

[0010] As a preferred solution, the nitriding gas is a mixture of N2 and H2, and the molar ratio range of N2 to H2 is set to [1:2, 2:1]; the flow rate range of the nitriding gas is set to [600sccm, 800sccm].

[0011] As a preferred solution, the acid pickling treatment in step S3 adopts nitric acid, and the concentration range of nitric acid is set to [25%, 35%].

[0012] As a preferred solution, the process parameters of the acid pickling treatment in step S3 are: the acid pickling temperature range is set to [40°C, 60°C]; the acid pickling time range is set to [20min, 50min].

[0013] As a preferred solution, the carburizing gas used in the carburizing treatment in step S4 is a mixture of acetylene and argon, and the molar ratio range of acetylene to argon is set to [3:1, 8:1].

[0014] As a preferred solution, the process parameters of the carburizing treatment in step S4 are as follows: the range of the carburizing temperature is set to [550 °C, 750 °C]; the range of the carburizing time is set to [6 h, 10 h].

[0015] In a second aspect, the present invention provides a titanium bipolar plate, which is obtained by the treatment method described in the first aspect.

[0016] Compared with the prior art, the present invention has the following beneficial effects: In view of the strict requirements of the hydrogen-electricity coupling system for hydrogen fuel cells, and the technical bottleneck existing in the single nitriding treatment of existing titanium bipolar plates - the nitriding process window is narrow (excessive nitriding easily leads to the rapid stacking growth of TiN, affecting the coating uniformity; insufficient nitriding is difficult to achieve complete coverage of the substrate, and even defects such as local stacking and non-coverage coexist), the present invention proposes a three-stage synergistic mechanism of nitriding - acid pickling - carburizing to construct a "gradient functionalization" protection system on the surface of the titanium bipolar plate - the nitrided layer provides basic corrosion resistance, the acid pickled layer ensures denseness, and the carburized layer guarantees conductivity. The three work together to solve the contradiction between durability and conductivity under fluctuating working conditions.

[0017] Furthermore, more detailed beneficial effects will be described in combination with specific embodiments in the specific implementation manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 It is a flow chart of the treatment method described in the embodiment of the present invention. SPECIFIC IMPLEMENTATION MANNER

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in combination with the drawings in the embodiments of the present invention.

[0021] In the following description, multiple embodiments of the present invention are provided, and different embodiments can be replaced or combined. Therefore, the present invention can also be considered to include all possible combinations of the same and / or different embodiments described. Thus, if one embodiment includes features A, B, and C, and another embodiment includes features B and D, then the present invention should also be considered to include embodiments containing all other possible combinations of A, B, C, and D, even though such embodiments may not be explicitly described in the following content.

[0022] The following description provides examples and does not limit the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the elements described without departing from the scope of the present disclosure. Various processes or components may be appropriately omitted, substituted, or added to each example. For example, the methods described may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with respect to some examples may be combined into other examples.

[0023] To facilitate a better understanding of the embodiments of the present invention, before explaining the specific embodiments of the present invention in detail, its application scenarios will be described first.

[0024] The processing method described in the embodiments of this specification is applied to the manufacturing process of hydrogen fuel cell titanium bipolar plates in a hydrogen-electric coupling system. In these scenarios, the application of the processing method aims to significantly improve the durability and conductivity of the bipolar plates under fluctuating operating conditions.

[0025] The following provides a brief explanation of the hydrogen-electric coupling system involved in this specification: A hydrogen-electric coupling system is an integrated energy system that combines renewable energy (such as wind energy and solar energy) with hydrogen energy technology, aiming to achieve efficient utilization, storage, and scheduling of energy. Currently, commonly used hydrogen-electric coupling systems generally include the following core units: (1) A renewable energy power generation unit, including wind power generation and photovoltaic power generation equipment, for converting wind energy and solar energy into electrical energy; (2) An electrical energy conversion unit, which converts the alternating current generated by renewable energy into direct current to meet the requirements of hydrogen production equipment; (3) A hydrogen production unit, which uses electrolysis technology to convert electrical energy into hydrogen, usually using a proton exchange membrane (PEM) electrolyzer or an alkaline electrolyzer; (4) A hydrogen storage unit, which stores the produced hydrogen through high-pressure hydrogen storage tanks or solid hydrogen storage materials for subsequent use; (5) A hydrogen fuel cell unit, which converts the stored hydrogen into electrical energy and heat energy through a fuel cell for power supply or heating; (6) An energy storage unit, including a battery energy storage system, for short-term energy regulation and standby power supply.

[0026] When the hydrogen-electric coupling system is operating, it uses wind energy and solar energy power generation equipment to generate electrical energy under good wind and light conditions; when the generated power exceeds the demand, the excess electrical energy is used to produce hydrogen through electrolysis and convert the electrical energy into hydrogen for storage; when the wind and light conditions are insufficient, the stored hydrogen is used to generate power through a hydrogen fuel cell to provide electrical energy and heat energy for the system; through this, the coordinated optimization among wind energy, solar energy, hydrogen energy, and battery energy storage can be achieved through an intelligent control system to ensure the stability and efficiency of energy supply.

[0027] Embodiment 1: As Figure 1As shown in the figure, this embodiment provides a processing method for a titanium bipolar plate of a hydrogen fuel cell, including the following steps: (1) Pretreat the titanium bipolar plate to remove impurities and oxide films on its surface; (2) Nitriding treatment is carried out on the pretreated titanium bipolar plate; (3) Acid pickling treatment is carried out on the nitrided titanium bipolar plate to form a passivation layer; (4) Carburizing treatment is carried out on the titanium bipolar plate after acid pickling treatment.

[0028] Preferably, the titanium bipolar plate in this embodiment is a titanium metal bipolar plate or a titanium alloy bipolar plate.

[0029] Specifically, in step (1) of this embodiment, pretreating the titanium bipolar plate to remove impurities and oxide films on its surface is well-known in the art. Further, during pretreatment, first, the surface of the titanium bipolar plate is polished, and then ultrasonic cleaning is carried out. For example, ultrasonic cleaning is carried out with acetone, hydrochloric acid, deionized water, and absolute ethanol respectively, and then it is dried for standby; the specific cleaning steps are well-known in the art and will not be elaborated in this embodiment.

[0030] Specifically, in step (2) of this embodiment, nitriding treatment is carried out on the pretreated titanium bipolar plate. Nitriding treatment is a commonly used metal surface treatment process in the art, such as plasma nitriding process or thermochemical treatment nitriding process, which can effectively improve the corrosion resistance of metals. Further, during nitriding treatment, the titanium bipolar plate is placed in a plasma nitriding furnace, evacuated, and after argon replacement, the voltage is turned on, and nitriding gas is introduced and then heated up for nitriding treatment.

[0031] Specifically, in step (2) of this embodiment, during nitriding treatment, the voltage is 600V - 700V, preferably 620V - 680V, for example, 650V.

[0032] Specifically, in step (2) of this embodiment, during nitriding treatment, the nitriding temperature is 750°C - 850°C, preferably 780 - 820°C, for example, 800°C, the nitriding time is 6 hours to 10 hours, for example, 8 hours, and the furnace internal pressure is 200Pa - 250Pa, preferably 210Pa - 240Pa, for example, 220Pa.

[0033] Specifically, the nitriding gas in this embodiment is a mixed gas of N2 and H2 with a molar ratio of 1:2 - 2:1, for example, 1:1, and the flow rate of the nitriding gas is 600sccm - 800sccm, preferably 650sccm - 750sccm, for example, 700sccm.

[0034] Specifically, in step (3) of this embodiment, the nitrided titanium bipolar plate is subjected to acid leaching treatment for passivation, and further a passivation protection layer is formed on the surface of the titanium bipolar plate.

[0035] Specifically, in step (3) of this embodiment, when performing the acid leaching treatment, the acid solution used has a concentration of 25% - 35%, preferably 28% - 32%, for example 30% nitric acid.

[0036] Specifically, in step (3) of this embodiment, when performing the acid leaching treatment, the acid leaching temperature is 40°C - 60°C, preferably 45°C - 55°C, for example 50°C, and the acid leaching time is 20 min - 50 min, for example 30 min or 40 min.

[0037] Specifically, in step (4) of this embodiment, the acid - leached titanium bipolar plate is subjected to carburizing treatment to further improve the surface properties, enhance the conductive effect, and reduce the contact resistance on the basis of nitriding and passivation treatments.

[0038] Specifically, in step (4) of this embodiment, when performing the carburizing treatment, the carburizing gas used is a mixture of acetylene and argon with a molar ratio of 3:1 to 8:1, for example 5:1 or 6:1 or 7:1, preferably 4:1 to 6:1.

[0039] Specifically, in step (4) of this embodiment, when performing carburizing, the titanium bipolar plate is subjected to thermochemical treatment in the atmosphere of the carburizing gas. The treatment temperature is 550°C - 750°C, preferably 600 - 720°C, for example 600°C or 700°C, and the treatment time is 6 hours to 10 hours, for example 8 hours.

[0040] Example Two: This embodiment provides a titanium bipolar plate, which is obtained by the treatment method described in Example One.

[0041] Example Three: In order to verify the effectiveness of the treatment method of a hydrogen fuel cell titanium bipolar plate described in this specification, this embodiment designs the following four groups of comparative experimental schemes: The control group 1 adopts the treatment method described in this specification, and by changing the process parameters of the nitriding treatment and / or the acid leaching treatment and / or the carburizing treatment, samples 1 - 5 are obtained: Sample 1: (1) Pretreat the titanium bipolar plate to remove impurities and oxide films on its surface; (2) Place the pretreated titanium metal bipolar plate in a plasma nitriding furnace. After evacuating and replacing with argon, apply voltage and introduce nitriding gas (a mixture of N2 and H2 with a molar ratio of 1:1 and a flow rate of 700 sccm), then raise the temperature for nitriding treatment; the voltage is 620 V, the temperature is 850 °C, the nitriding time is 7 hours, and the furnace pressure is 200 Pa; (3) Immerse the nitrided titanium metal bipolar plate in nitric acid with a concentration of 30% for acid leaching treatment. The acid leaching temperature is 50 °C and the acid leaching time is 30 min to form a passivation layer; (4) Carry out thermochemical carburizing treatment on the acid-leached titanium metal bipolar plate in the atmosphere of carburizing gas (a mixture of acetylene and argon with a molar ratio of 4:1). The treatment temperature is 750 °C and the treatment time is 6 hours.

[0042] Sample 2: (1) Pretreat the titanium bipolar plate to remove impurities and oxide films on its surface; (2) Place the pretreated titanium metal bipolar plate in a plasma nitriding furnace. After evacuating and replacing with argon, apply voltage and introduce nitriding gas (a mixture of N2 and H2 with a molar ratio of 1:2 and a flow rate of 800 sccm), then raise the temperature for nitriding treatment; the voltage is 700 V, the temperature is 750 °C, the nitriding time is 10 hours, and the furnace pressure is 230 Pa; (3) Immerse the nitrided titanium metal bipolar plate in nitric acid with a concentration of 35% for acid leaching treatment. The acid leaching temperature is 45 °C and the acid leaching time is 45 min to form a passivation layer; (4) Carry out thermochemical carburizing treatment on the acid-leached titanium metal bipolar plate in the atmosphere of carburizing gas (a mixture of acetylene and argon with a molar ratio of 8:1). The treatment temperature is 650 °C and the treatment time is 8 hours.

[0043] Sample 3: (1) Pretreat the titanium bipolar plate to remove impurities and oxide films on its surface; (2) Place the pretreated titanium metal bipolar plate in a plasma nitriding furnace. After evacuating and replacing with argon, apply voltage and introduce nitriding gas (a mixture of N2 and H2 with a molar ratio of 2:1 and a flow rate of 600 sccm), then raise the temperature for nitriding treatment; the voltage is 650 V, the temperature is 800 °C, the nitriding time is 8 hours, and the furnace pressure is 250 Pa; (3) Immerse the nitrided titanium metal bipolar plate in nitric acid with a concentration of 25% for acid leaching treatment. The acid leaching temperature is 55 °C and the acid leaching time is 25 min to form a passivation layer; (4) The acid-leached titanium bipolar plate is subjected to thermochemical carburization treatment in an atmosphere of carburizing gas (a mixture of acetylene and argon with a molar ratio of 5:1), the treatment temperature is 700 °C, and the treatment time is 7 hours.

[0044] Sample 4: (1) Pretreat the titanium bipolar plate to remove impurities and oxide films on its surface; (2) Place the pretreated titanium bipolar plate in a plasma nitriding furnace. After evacuating and replacing with argon, apply voltage and introduce nitriding gas (a mixture of N2 and H2 with a molar ratio of 1:1 and a flow rate of 750 sccm), then heat up for nitriding treatment; the voltage is 600 V, the temperature is 800 °C, the nitriding time is 8 hours, and the furnace pressure is 210 Pa; (3) Immerse the nitrided titanium bipolar plate in nitric acid with a concentration of 28% for acid leaching treatment. The acid leaching temperature is 50 °C and the acid leaching time is 40 min to form a passivation layer; (4) The acid-leached titanium bipolar plate is subjected to thermochemical carburization treatment in an atmosphere of carburizing gas (a mixture of acetylene and argon with a molar ratio of 6:1), the treatment temperature is 680 °C, and the treatment time is 8 hours.

[0045] Sample 5: (1) Pretreat the titanium bipolar plate to remove impurities and oxide films on its surface; (2) Place the pretreated titanium bipolar plate in a plasma nitriding furnace. After evacuating and replacing with argon, apply voltage and introduce nitriding gas (a mixture of N2 and H2 with a molar ratio of 1:1 and a flow rate of 650 sccm), then heat up for nitriding treatment; the voltage is 680 V, the temperature is 780 °C, the nitriding time is 8 hours, and the furnace pressure is 240 Pa; (3) Immerse the nitrided titanium bipolar plate in nitric acid with a concentration of 32% for acid leaching treatment. The acid leaching temperature is 45 °C and the acid leaching time is 45 min to form a passivation layer; (4) The acid-leached titanium bipolar plate is subjected to thermochemical carburization treatment in an atmosphere of carburizing gas (a mixture of acetylene and argon with a molar ratio of 5:1), the treatment temperature is 720 °C, and the treatment time is 8 hours.

[0046] The difference between the treatment of Sample 6 in Comparative Group 2 and that of Sample 1 in Comparative Group 1 is that no acid leaching treatment is carried out, and the rest of the operations are the same.

[0047] The difference between the treatment of Sample 7 in Comparative Group 3 and that of Sample 2 in Comparative Group 1 is that no acid leaching treatment and carburization treatment are carried out, and the rest of the operations are the same.

[0048] The difference in the treatment of the sample 3 between the comparison group 4 and the comparison group 1 is that carburizing treatment is first carried out, and then acid pickling treatment is carried out, and the remaining operations are the same, and the sample 8 is obtained.

[0049] The corrosion resistance of the above samples 1-8 in a simulated fuel cell environment was tested by an IVIUM electrochemical workstation respectively. The standard three-electrode system was adopted, with the sample as the working electrode, the platinum electrode as the counter electrode, and the saturated calomel electrode (SCE) as the reference electrode. The test solution was 0.5M H2SO4 + 4ppm HF (simulating the PEMFCs environment), the test temperature was 70 °C, and the test potential (+1.6V SCE) polarization test was carried out for 4h to detect the corrosion resistance of the bipolar plate; at the same time, the surface contact resistance test was used to evaluate the electrical conductivity, the test pressure was 0.6MPa, and the test results are shown in Table 1 below.

[0050] Table 1:

[0051] It can be seen from Table 1 that the corrosion resistance and electrical conductivity of the samples prepared by the comparison group 1 by adopting the treatment method described in this specification are both better, significantly higher than those of the comparison groups 2-4, that is, this embodiment verifies the effectiveness of the treatment method of a titanium bipolar plate for a hydrogen fuel cell in this specification.

[0052] It should be noted that for the foregoing method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present invention is not limited by the described action sequence, because according to the present invention, certain steps can be carried out in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0053] In the above embodiments, the descriptions of each embodiment have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0054] The above are only the exemplary embodiments of the present invention, and the scope of the present invention cannot be limited thereby. That is, all equivalent changes and modifications made in accordance with the teachings of the present invention still fall within the scope covered by the present invention. Those skilled in the art will easily think of other embodiments of the present invention after considering the specification and practicing the disclosure herein. The present invention aims to cover any variations, uses or adaptations of the present invention, which follow the general principles of the present invention and include the common general knowledge or conventional technical means in the technical field not recorded in the present invention. The specification and embodiments are only regarded as exemplary, and the scope and spirit of the present invention are defined by the claims.

Claims

1. A processing method for a titanium bipolar plate of a hydrogen fuel cell, characterized in that The titanium bipolar plate is a titanium metal bipolar plate or a titanium alloy bipolar plate, and the treatment method includes the steps: S1. Pretreat the titanium bipolar plate to remove impurities and oxide films on its surface; S2. Nitriding treatment is carried out on the pretreated titanium bipolar plate; S3. Acid pickling treatment is carried out on the nitrided titanium bipolar plate to form a passivation layer; S4. Carburizing treatment is carried out on the titanium bipolar plate after acid pickling treatment.

2. The processing method of a titanium bipolar plate for a hydrogen fuel cell according to claim 1, characterized in that The pretreatment described in step S1 is specifically: The titanium bipolar plate is surface polished, ultrasonically cleaned, and dried for later use; The ultrasonic cleaning is carried out in acetone or hydrochloric acid or deionized water or absolute ethanol.

3. The processing method of a titanium bipolar plate for a hydrogen fuel cell according to claim 1, characterized in that, The nitriding treatment described in step S2 adopts a plasma nitriding process or a thermochemical treatment nitriding process. The specific steps of adopting the plasma nitriding process include: Place the titanium bipolar plate in a plasma nitriding furnace, evacuate and then connect the voltage after argon replacement, and introduce nitriding gas and then heat up to carry out nitriding treatment.

4. A method for treating a titanium bipolar plate of a hydrogen fuel cell according to claim 3, characterized in that, The process parameters of the nitriding treatment are: The range of the voltage is set to [600V, 700V]; The range of the nitriding temperature is set to [750°C, 850°C]; The range of the nitriding time is set to [6h, 10h]; The range of the furnace internal pressure of the plasma nitriding furnace is set to [200Pa, 250Pa].

5. According to the treatment method of a hydrogen fuel cell titanium bipolar plate described in claim 3 or 4, it is characterized in that: The nitriding gas is a mixture of N2 and H2, and the range of the molar ratio of N2 to H2 is set to [1:2, 2:1]; The flow rate range of the nitriding gas is set to [600sccm, 800sccm].

6. According to the treatment method of a hydrogen fuel cell titanium bipolar plate described in claim 1, it is characterized in that: The acid pickling treatment described in step S3 adopts nitric acid, and the concentration range of nitric acid is set to [25%, 35%].

7. A processing method for a titanium bipolar plate of a hydrogen fuel cell according to claim 1 or 6, characterized in that, The process parameters of the acid pickling treatment described in step S3 are: The range of the acid pickling temperature is set to [40°C, 60°C]; The range of the acid pickling time is set to [20min, 50min].

8. According to the treatment method of a hydrogen fuel cell titanium bipolar plate described in claim 1, it is characterized in that: The carburizing gas adopted in the carburizing treatment described in step S4 is a mixture of acetylene and argon, and the range of the molar ratio of acetylene to argon is set to [3:1, 8:1].

9. A method for treating a titanium bipolar plate of a hydrogen fuel cell according to claim 1 or 8, characterized in that, The process parameters of the carburizing treatment described in step S4 are: The range of the carburizing temperature is set to [550°C, 750°C]; The range of the carburizing time is set to [6h, 10h].

10. A titanium bipolar plate, characterized in that, It is obtained by the treatment method described in any one of claims 1 to 9.

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