A method of making a fuel cell cathode plate resistant to cathode poisoning

Abstract

The application relates to a preparation method of a fuel cell cathode plate resistant to cathode poisoning, and belongs to the technical field of fuel cells. The method comprises the following steps: obtaining an iron-based substrate with a set chemical composition and a first set thickness; obtaining a nickel-based substrate with a second set thickness; performing grinding and degreasing treatment on the iron-based substrate and the nickel-based substrate, and controlling the surface roughness of the iron-based substrate and the nickel-based substrate; performing cold composite rolling on the iron-based substrate and the nickel-based substrate after the degreasing treatment to obtain a composite strip; and sequentially performing annealing, edge cutting and sizing and runner machining on the composite strip to obtain a cathode plate. The cathode plate has stable electrochemical performance and a low ASR value at high temperature, and contains less Cr-containing substances deposited on the cathode, and can meet the high requirements of fuel cells on cathode materials.

Description

Technical Field

[0001] This application relates to the field of fuel cell technology, and in particular to a method for preparing a fuel cell cathode plate resistant to cathode poisoning. Background Technology

[0002] High-temperature solid oxide fuel cells (SOFCs) are highly efficient energy conversion devices that can directly convert the chemical energy of fuel into electrical energy at temperatures as high as 800°C. They can directly use carbon-containing gases such as methane, natural gas, and water gas as fuel. With continuous improvements in material manufacturing processes and design technologies, the operating temperature of SOFCs has been reduced from the traditional 1000°C to a mid-temperature range of 600–800°C. This change makes it possible to use metallic interconnect materials, as metallic interconnects can meet the basic requirements for electrical conductivity, coefficient of thermal expansion, thermal conductivity, and oxidation resistance within this operating temperature range. Currently, the four most studied ferritic stainless steel interconnects are Crofer 22APU, SUS430, X10CrAl18, and ZMG232.

[0003] Despite the superior performance of these alloys, their commercial application still faces bottlenecks and cannot currently meet the requirements for long-term operation of SOFC stacks. The main problem lies in the fact that chromium-containing alloys form volatile gaseous substances in oxidizing environments. These volatile substances deposit on the cathode surface, severely damaging the electrochemical performance of SOFCs—a problem known as cathode poisoning. Currently, commercial alloys generally address cathode poisoning by coating them with the cathode. However, this method increases production steps, prolongs the preparation process, raises processing costs, and may lead to reduced production efficiency. Furthermore, the coating process may also cause environmental pollution. Summary of the Invention

[0004] This application provides a method for preparing a fuel cell cathode plate resistant to cathode poisoning, in order to solve the following technical problem: how to solve the cathode poisoning problem caused by Cr volatilization in existing fuel cell cathode plates at 600℃~900℃.

[0005] This application provides a method for preparing a fuel cell cathode plate resistant to cathode poisoning, the method comprising:

[0006] An iron-based substrate with a set chemical composition and a first set thickness is obtained;

[0007] A nickel-based substrate with a second predetermined thickness is obtained;

[0008] The iron-based substrate and the nickel-based substrate are ground and degreased, and the surface roughness of the iron-based substrate and the nickel-based substrate is controlled.

[0009] The degreased iron-based substrate and the nickel-based substrate are cold composite rolled to obtain a composite strip.

[0010] The composite strip is subjected to annealing, edge trimming and length cutting, and flow channel processing in sequence to obtain the cathode plate.

[0011] Optionally, the deformation per pass in the cold composite rolling is 40% to 75%.

[0012] Optionally, the annealing temperature is 270℃~350℃, the annealing holding time is 1h~5h, and the hydrogen injection rate during annealing is ≥20m³. 3 / h.

[0013] Optionally, the surface roughness of the iron-based substrate is 80 μm to 120 μm.

[0014] Optionally, the surface roughness of the nickel-based substrate is 50 μm to 80 μm.

[0015] Optionally, the specified chemical composition, by mass fraction, includes: Cr: 20%–25%, Nb: 0.2%–1.0%, W: 1%–3%, Si: 0.15%–0.3%, Mn: 0.1%–0.8%, Al: 0.15%–0.4%, C+N≤0.010%, O≤0.0020%, and the matrix element Fe; where C+N represents the sum of the mass fractions of C and N.

[0016] Optionally, the first set thickness is 2mm to 7mm.

[0017] Optionally, the chemical composition of the nickel-based substrate, by mass fraction, includes: Ni ≥ 99.5%.

[0018] Optionally, the second set thickness satisfies the following relationship: 0.1mm ≥ h*ka ≥ 0.01mm;

[0019] Where h represents the second set thickness of the nickel-based substrate, k represents the deformation rate of the nickel-based substrate during the cold composite rolling process, and a represents the processing depth of the flow channel machining.

[0020] Optionally, under an O2-H2O atmosphere, after the cathode plate is oxidized at 600℃~900℃ for 40000h, the ASR ≤ 0.015Ω·cm 2 .

[0021] Optionally, the cathode plate, at a temperature above 900°C, when subjected to a current of 400 mA / cm², 2 After 4000 hours of polarization with the current, the Cr-containing material deposited on the cathode is ≤0.05 mg / cm³. 2 .

[0022] The technical solutions provided in this application have the following advantages compared with the prior art:

[0023] This application provides a method for preparing a fuel cell cathode plate resistant to cathode poisoning. The method includes: obtaining an iron-based substrate with a predetermined chemical composition and a first predetermined thickness; obtaining a nickel-based substrate with a second predetermined thickness; grinding and degreasing the iron-based substrate and the nickel-based substrate, and controlling the surface roughness of the iron-based substrate and the nickel-based substrate; cold-composite rolling the degreased iron-based substrate and the nickel-based substrate to obtain a composite strip; and sequentially annealing, trimming, and flow channel machining of the composite strip to obtain a cathode plate. By cold-composite rolling the iron-based substrate and the nickel-based substrate, controlling the rolling parameters, the surface hardened layer of the composite metal material is broken under high rolling force and welded under high pressure. Annealing further allows for the full diffusion of metal atoms, achieving a strong metallurgical bond. This method achieves the composite formation of a Ni metal layer on the cathode side of the solid oxide fuel cell substrate, preventing cathode plate poisoning. Attached Figure Description

[0024] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic flowchart illustrating a method for preparing a cathode plate for a fuel cell resistant to cathode poisoning, as provided in an embodiment of this application. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range; for example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range such as 1, 2, 3, 4, 5, and 6, regardless of the range; in addition, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0029] In this document, terms such as “comprising” mean “including but not limited to”. Relational terms such as “first” and “second” are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. “And / or” describes the relationship between related objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone; where A and B can be singular or plural. “At least one” means one or more, “more” means two or more; “at least one,” “at least one of the following,” or similar expressions refer to any combination of these items, including any combination of single or plural items; for example, “at least one of a, b, or c,” or “at least one of a, b, and c,” can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple. "Parts representation" such as parts by weight or parts by mass indicates the proportional relationship between components. In the proportional relationships discussed in this article, the parameters that need to be described by proportion should be understood as the first term of the proportion in the order of description, and the proportion figures should be understood as the second term of the proportion. For example, if the mass ratio of substance A, substance B, and substance C is 1:2:3, then substances A, B, and C should correspond one-to-one with the proportion figures in the proportion in the order of description, that is, the mass of substance A: the mass of substance B: the mass of substance C = 1:2:3.

[0030] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this article can be purchased from the market or prepared by existing methods.

[0031] Figure 1 This is a schematic flowchart illustrating a method for preparing a cathode plate for a fuel cell resistant to cathode poisoning, as provided in an embodiment of this application.

[0032] like Figure 1 As shown in the embodiment of this application, a method for preparing a fuel cell cathode plate resistant to cathode poisoning is provided, the method comprising:

[0033] S1. Obtain an iron-based substrate with a set chemical composition and a first set thickness;

[0034] In some embodiments, the specified chemical composition, by mass fraction, includes: Cr: 20%–25%, Nb: 0.2%–1.0%, W: 1%–3%, Si: 0.15%–0.3%, Mn: 0.1%–0.8%, Al: 0.15%–0.4%, C+N≤0.010%, O≤0.0020%, and the matrix element Fe; where C+N represents the sum of the mass fractions of C and N.

[0035] As a common conductive material, the chemical composition control during the preparation of iron-based substrates is crucial. In addition to the main element, iron, appropriate amounts of alloying elements, such as chromium, are added. Chromium enhances the substrate's corrosion resistance. The amount and proportion of alloying elements added need to be precisely controlled according to actual requirements to ensure that the substrate meets conductivity requirements while also possessing sufficient corrosion resistance and mechanical strength.

[0036] In some embodiments, the first set thickness is 2mm to 7mm.

[0037] The thickness of the iron-based substrate needs to be determined according to the design requirements of the fuel cell. During the manufacturing process, hot rolling, cold rolling, annealing and other processes are required to ensure that the substrate reaches the required thickness.

[0038] S2. Obtain a nickel-based substrate with a second predetermined thickness;

[0039] The thickness of the nickel-based substrate is related to the subsequent processing parameters and needs to be determined based on those parameters.

[0040] In some embodiments, the chemical composition of the nickel-based substrate, by mass fraction, includes: Ni ≥ 99.5%.

[0041] This means that nickel-based substrates are primarily composed of nickel, and the nickel content is extremely high; they are commonly referred to as high-purity nickel or pure nickel substrates. High-purity nickel substrates possess excellent electrical conductivity, thermal conductivity, and corrosion resistance.

[0042] In some embodiments, the second set thickness satisfies the following relationship: 0.1mm ≥ h*ka ≥ 0.01mm;

[0043] Where h represents the second set thickness of the nickel-based substrate, k represents the deformation rate of the nickel-based substrate during the cold composite rolling process, and a represents the processing depth of the flow channel machining.

[0044] Deformation rate k: During the cold composite rolling process, the nickel-based substrate undergoes a certain degree of deformation. The deformation rate k is a parameter used to describe the degree of deformation; it is equal to the ratio of the deformed dimension to the original dimension.

[0045] The machining depth 'a' in flow channel machining refers to the depth of the channel on the cathode plate used for gas flow, which affects the gas flow efficiency and battery performance.

[0046] S3. Grind and degrease the iron-based substrate and the nickel-based substrate, and control the surface roughness of the iron-based substrate and the nickel-based substrate.

[0047] Before cold composite rolling, grinding and degreasing of the substrate are crucial. Grinding penetrates deep into the substrate surface to remove defects, impurities, and contaminants that affect surface flatness and quality, resulting in a smoother, flatter surface that ensures smooth operation of subsequent processes. Degreasing, on the other hand, primarily uses chemical or physical methods to thoroughly remove organic matter such as grease, lubricating oil, and rust-preventive oil adhering to the substrate surface, exposing a clean metal substrate. This ensures good wettability and adhesion between the substrate and the other metal material during cold composite rolling. In this embodiment, grinding wheels or similar methods can be used to grind the iron-based and nickel-based substrates, and anhydrous ethanol or similar degreasing agents can be used to degrease and clean the surfaces of the iron-based and nickel-based substrates.

[0048] In some embodiments, the surface roughness of the iron-based substrate is 80 μm to 120 μm.

[0049] In some embodiments, the surface roughness of the nickel-based substrate is 50 μm to 80 μm.

[0050] S4. The degreased iron-based substrate and the nickel-based substrate are subjected to cold composite rolling to obtain a composite strip.

[0051] Cold composite rolling is a rolling process performed at room temperature that combines two or more metallic materials to form a composite material. This method allows for precise control of the composite material's thickness, composition, and microstructure, thereby optimizing its performance. Cold composite rolling can produce composite materials with excellent oxidation resistance and electrical conductivity, which can be used as cathodes or cathode coatings in SOFCs. During cold composite rolling, parameters such as rolling force, rolling speed, and temperature need to be precisely controlled to ensure a good metallurgical bond between the two substrates while avoiding cracks and defects. In the embodiments of this application, the yield of the composite strip is ≥85%, and the production efficiency of the composite strip is 100 kg / h to 300 kg / h.

[0052] In some embodiments, the single-pass deformation amount of the cold composite rolling is 40% to 75%.

[0053] The bonding strength of the metal composite strip increases with the amount of deformation, leading to an increase in the number of activated metal atoms and thus an increase in the bonding strength of the composite strip. However, due to the special properties of the ferrite structure of the iron-based substrate, the grain boundary bonding force is weak, and excessive deformation will cause the ferrite substrate to crack. Therefore, the embodiments of this application limit the deformation amount per pass to 40% to 75%. A deformation amount below 40% will lead to rolling failure; a deformation amount above 75% will increase the risk of cracking of the iron-based substrate. For example, the deformation amount per pass in cold composite rolling can be 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, etc.

[0054] S5. The composite strip is sequentially annealed, trimmed to length, and processed by a flow channel machine to obtain a cathode plate.

[0055] After the cold composite rolling process, the composite substrate requires a series of post-processing operations to ensure it meets the quality requirements of the final product—the cathode plate. Cold composite rolling creates localized weld points between the two substrates, primarily through mechanical interlocking. Diffusion annealing then initiates new bonding points, allowing atomic interpenetration across the entire contact surface. Next, the composite substrate undergoes precise edge trimming and sizing according to the specific dimensional requirements and design specifications of the cathode plate. This step aims to remove excess material, precisely control the dimensional accuracy of the cathode plate, and ensure its good fit with the overall assembly and other components, meeting all technical standards for fuel cell system operation. Finally, a complex flow channel system is meticulously etched onto the cathode plate using flow channel machining technology. These flow channels are crucial components for the normal operation of the fuel cell, responsible for evenly distributing the reactant gases to all corners of the cell, ensuring sufficient contact between the cell surface and the chemical reaction.

[0056] In some embodiments, the annealing temperature is 270℃~350℃, the annealing holding time is 1h~5h, and the hydrogen injection rate during annealing is ≥20m³. 3 / h.

[0057] Annealing temperatures below 270°C are insufficient to achieve complete diffusion and penetration; annealing temperatures above 350°C will lead to the precipitation of brittle phases. For example, annealing temperatures can be 270°C, 280°C, 290°C, 300°C, 310°C, 320°C, 330°C, 340°C, 350°C, etc.

[0058] Hydrogen injection can protect materials from oxidation during annealing and also helps control the atmosphere inside the furnace. For example, the hydrogen injection rate for annealing is 20 m³ / h and 22 m³ / h. 3 / h、24m 3 / h、26m 3 / h、28m 3 / h, 30m 3 / h etc.

[0059] In this embodiment, a box furnace is used for annealing. Box furnaces are compact, easy to operate, and suitable for annealing various materials. By adjusting parameters such as the hydrogen injection rate, the atmosphere inside the furnace can be precisely controlled, ensuring consistent annealing results. Box furnaces typically have high thermal efficiency and low energy consumption, which helps reduce production costs.

[0060] In some embodiments, after the cathode plate is oxidized at 600℃~900℃ for 40000h in an O2-H2O atmosphere, the ASR ≤ 0.015Ω·cm 2 .

[0061] In fuel cell systems, the cathode plate serves as a crucial carrier for gas diffusion and electrochemical reactions, and its conductivity directly impacts the overall system efficiency. ASR (area resistivity) is an indicator of a material's conductivity; a lower ASR indicates better conductivity. In the embodiments of this application, after oxidation at 600℃~900℃ for 40000h, the cathode plate exhibits an ASR ≤ 0.015 Ω·cm. 2 This result indicates that the cathode plate maintains good conductivity over a long period of time under high temperature and oxidizing conditions.

[0062] In some embodiments, the cathode plate is subjected to a temperature above 900°C when a current of 400 mA / cm is applied. 2 After 4000 hours of polarization with the current, the Cr-containing material deposited on the cathode is ≤0.05 mg / cm³. 2 .

[0063] The evaluation of cathode deposition after high-temperature polarization is a key performance indicator for cathode plates. During actual operation, fuel cells may experience electrode polarization under high-temperature and polarized conditions, leading to the formation of deposits on the cathode plate surface. These deposits are complex in composition and may include metal oxides, hydroxides, and other chemical products. The presence of these deposits not only occupies valuable reaction area but may also alter the physicochemical properties of the cathode plate, such as reducing gas diffusion rates and increasing electrode internal resistance. Therefore, it is necessary to evaluate the type and quantity of deposits on the cathode plate after high-temperature polarization. In the embodiments of this application, the cathode plate is subjected to a temperature above 900°C, when a flow rate of 400 mA / cm² is applied... 2 After 4000 hours of polarization with the current, the Cr-containing material deposited on the cathode is ≤0.05 mg / cm³. 2 This result indicates that the cathode plate exhibits good resistance to Cr volatilization under high temperature and current conditions.

[0064] The preparation method provided in this application ensures that the final cathode plate has excellent resistance to cathode poisoning by precisely controlling the chemical composition, thickness, surface roughness, and process parameters such as cold composite rolling and annealing of the iron-based and nickel-based substrates. This not only improves the efficiency and lifespan of fuel cells but also provides technical support for their application in a wider range of fields.

[0065] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national / industry standards; if there is no corresponding national / industry standard, they are performed according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0066] Example 1

[0067] A 5mm thick iron-based substrate was obtained. The chemical composition of the iron-based substrate included: Cr: 22%, Nb: 0.5%, W: 1%, Si: 0.1%, Mn: 0.1%, Al: 0.2%, C+N≤0.010%, O: 0.0018%, and the remainder was Fe.

[0068] The thickness of the nickel-based substrate is 1 mm; after grinding and degreasing the iron-based substrate and the nickel-based substrate, the surface roughness of the iron-based substrate is 80 μm and the surface roughness of the nickel-based substrate is 50 μm.

[0069] The single-pass deformation of cold composite rolling is 50%, the yield of composite strip is 88%, and the production efficiency of composite strip is 150 kg / h.

[0070] Annealing was performed in a box furnace at a temperature of 300℃ for 2 hours, with a hydrogen injection rate of 20m³. 3 / h.

[0071] Trim the edges and determine the length to 2 meters.

[0072] The flow channel is machined on the nickel layer side of the composite strip to machine the gas flow channel groove of the cathode plate to a depth of 0.4 mm.

[0073] Performance of the obtained solid oxide fuel cell cathode plate:

[0074] Conductivity: Under an O2-H2O atmosphere, after oxidation at 600℃~900℃ for 40000h, the ASR is 0.015Ω·cm. 2 .

[0075] Cathode Cr volatility index: 400 mA / cm at cathode plate above 900℃ 2 After 4000 hours of current polarization, the Cr-containing material deposited at the cathode was 0.05 mg / cm³. 2 .

[0076] Example 2

[0077] A 2.5 mm thick iron-based substrate was obtained. The chemical composition of the iron-based substrate included: Cr: 22%, Nb: 0.5%, W: 1%, Si: 0.1%, Mn: 0.1%, Al: 0.2%, C+N≤0.010%, O: 0.0018%, and the remainder was Fe.

[0078] The thickness of the nickel-based substrate is 0.5 mm; after grinding and degreasing the iron-based substrate and the nickel-based substrate, the surface roughness of the iron-based substrate is 80 μm and the surface roughness of the nickel-based substrate is 50 μm.

[0079] The single-pass deformation of cold composite rolling is 75%, the yield of composite strip is 85%, and the production efficiency of composite strip is 100 kg / h.

[0080] Annealing was performed in a box furnace at a temperature of 320℃ for 1 hour, with a hydrogen injection rate of 20m³. 3 / h.

[0081] Trim the edges and determine the length to 2 meters.

[0082] The flow channel is machined on the nickel layer side of the composite strip to machine the gas flow channel groove of the cathode plate to a depth of 0.1 mm.

[0083] Performance of the obtained solid oxide fuel cell cathode plate:

[0084] Conductivity: Under an O2-H2O atmosphere, after oxidation at 600℃~900℃ for 40000h, the ASR is 0.013Ω·cm. 2 .

[0085] Cathode Cr volatility index: 400 mA / cm at cathode plate above 900℃ 2 After 4000 hours of current polarization, the Cr-containing material deposited at the cathode was 0.04 mg / cm³. 2 .

[0086] Comparative Example 1

[0087] A 2.5 mm thick iron-based substrate was obtained. The chemical composition of the iron-based substrate included: Cr: 22%, Nb: 0.5%, W: 1%, Si: 0.1%, Mn: 0.1%, Al: 0.2%, C+N≤0.010%, O: 0.0018%, and the remainder was Fe.

[0088] Annealing was performed in a box furnace at a temperature of 320℃ for 1 hour, with a hydrogen injection rate of 20m³. 3 / h.

[0089] Trim the edges and determine the length to 2 meters.

[0090] Perform flow channel machining to machine the gas flow channel grooves of the cathode plate to a depth of 0.1mm.

[0091] Performance of the obtained solid oxide fuel cell cathode plate:

[0092] Conductivity: Under an O2-H2O atmosphere, after oxidation at 600℃~900℃ for 40000h, the ASR is 0.5Ω·cm. 2 .

[0093] Cathode Cr volatility index: 400 mA / cm at cathode plate above 900℃ 2 After 4000 hours of current polarization, the Cr-containing material deposited at the cathode was 0.2 mg / cm³. 2 .

[0094] Comparative Example 2

[0095] A 5mm thick iron-based substrate was obtained. The chemical composition of the iron-based substrate included: Cr: 22%, Nb: 0.5%, W: 1%, Si: 0.1%, Mn: 0.1%, Al: 0.2%, C+N≤0.010%, O: 0.0018%, and the remainder was Fe.

[0096] The thickness of the nickel-based substrate is 1 mm; after grinding and degreasing the iron-based substrate and the nickel-based substrate, the surface roughness of the iron-based substrate is 80 μm and the surface roughness of the nickel-based substrate is 50 μm.

[0097] The deformation per pass in cold composite rolling is 35%.

[0098] Annealing was performed in a box furnace at a temperature of 300℃ for 2 hours, with a hydrogen injection rate of 20m³. 3 / h.

[0099] Trim the edges and determine the length to 2 meters.

[0100] The flow channel is machined on the nickel layer side of the composite strip to machine the gas flow channel groove of the cathode plate to a depth of 0.4 mm.

[0101] The composite nickel layer cracked, and the composite rolling process failed.

[0102] Comparative Example 3

[0103] A 5mm thick iron-based substrate was obtained. The chemical composition of the iron-based substrate included: Cr: 22%, Nb: 0.5%, W: 1%, Si: 0.1%, Mn: 0.1%, Al: 0.2%, C+N≤0.010%, O: 0.0018%, and the remainder was Fe.

[0104] The thickness of the nickel-based substrate is 1 mm; after grinding and degreasing the iron-based substrate and the nickel-based substrate, the surface roughness of the iron-based substrate is 80 μm and the surface roughness of the nickel-based substrate is 50 μm.

[0105] The deformation per pass in cold composite rolling is 70%.

[0106] Annealing was performed in a box furnace at a temperature of 400℃ for 2 hours, with a hydrogen injection rate of 20m³. 3 / h.

[0107] Trim the edges and determine the length to 2 meters.

[0108] The flow channel is machined on the nickel layer side of the composite strip to machine the gas flow channel groove of the cathode plate to a depth of 0.4 mm.

[0109] The annealing temperature in this comparative example was too high, which caused brittle phases to precipitate in the iron-based matrix, resulting in matrix cracking.

[0110] As can be seen from the above embodiments and comparative examples, the preparation process parameters of the embodiments are all within the required range of the present invention, and the obtained fuel cell cathode plate can effectively avoid the cathode poisoning problem caused by Cr volatilization at 600℃~900℃.

[0111] One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

[0112] Low energy consumption and low pollution: Compared with the traditional coating method, the cold rolling composite technology used in this embodiment of the invention does not require a high-temperature melting process, thus significantly reducing energy consumption and pollutant emissions.

[0113] High production efficiency: Cold rolling composite technology enables continuous production, which greatly improves production efficiency and shortens the production cycle.

[0114] Low cost: By eliminating complex processes such as high-temperature melting and spraying, the production cost of this invention is effectively controlled, making the product more competitive in the market.

[0115] Excellent performance: Through cold rolling and annealing, a strong metallurgical bond is achieved between the iron-based matrix and the nickel-based matrix, ensuring the stability and durability of the Ni metal layer on the cathode side of the SOFC substrate.

[0116] Preventing battery cathode plate poisoning: The Ni metal composite layer can effectively prevent the battery cathode plate from being poisoned by contact with harmful substances, thereby extending the service life of SOFC.

[0117] The method provided in this invention has the advantages of lower energy consumption, lower pollution, higher production efficiency, and lower cost compared to the coating method.

[0118] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A method for preparing a cathode plate for a fuel cell resistant to cathode poisoning, the method comprising: An iron-based substrate with a set chemical composition and a first set thickness is obtained; A nickel-based substrate with a second predetermined thickness is obtained; The iron-based substrate and the nickel-based substrate are subjected to grinding and degreasing treatment, and the surface roughness of the iron-based substrate and the nickel-based substrate is controlled. The degreased iron-based substrate and the nickel-based substrate are cold composite rolled to obtain a composite strip. The composite strip is sequentially annealed, trimmed to length, and processed using a flow channel machine to obtain a cathode plate; The single-pass deformation amount of the cold composite rolling is 40% to 75%; The annealing temperature is 270℃~350℃, the annealing holding time is 1h~5h, and the hydrogen injection rate during annealing is ≥20m³. 3 / h; The surface roughness of the iron-based substrate is 80 μm to 120 μm; the surface roughness of the nickel-based substrate is 50 μm to 80 μm. The specified chemical composition includes: Cr: 20%–25%, Nb: 0.2%–1.0%, W: 1%–3%, Si: 0.15%–0.3%, Mn: 0.1%–0.8%, Al: 0.15%–0.4%, C+N≤0.010%, O≤0.0020%, and the matrix element Fe; where C+N represents the sum of the mass fractions of C and N. The first set thickness is 2mm to 7mm; The chemical composition of the nickel-based substrate includes: Ni ≥ 99.5%; The second set thickness satisfies the following relationship: 0.1mm ≥ h*ka ≥ 0.01mm; Where h represents the second set thickness of the nickel-based substrate, k represents the deformation rate of the nickel-based substrate during the cold composite rolling process, and a represents the processing depth of the flow channel machining.

2. The method according to claim 1, characterized in that, Under an O2-H2O atmosphere, after the cathode plate is oxidized at 600℃~900℃ for 40000h, the ASR ≤ 0.015Ω. cm 2 .

3. The method according to claim 1, characterized in that, The cathode plate, at a temperature above 900°C, when subjected to 400 mA / cm... 2 After 4000 hours of polarization with the current, the Cr-containing material deposited on the cathode is ≤0.05 mg / cm³. 2 .

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