Bipolar plate, manufacturing method thereof and fuel cell

Abstract

The invention discloses a bipolar plate, a manufacturing method thereof and a fuel cell, and the manufacturing method of the bipolar plate comprises the following steps: selecting metal powder with conductive and heat-conducting properties, compounding and mixing the metal powder with a binder, a solvent and a pore-forming agent, and then carrying out high-temperature treatment to prepare a functional layer with a porous network structure; and selecting an ultra-thin metal layer, stacking the ultra-thin metal layer and the functional layer, and performing high-temperature sintering to obtain the bipolar plate. The manufacturing method of the bipolar plate is simple and reasonable, automatic, large-scale and efficient processing production can be realized, and the obtained bipolar plate has the characteristics of good heat conductivity, high electric conductivity, high mechanical strength, high air tightness, capability of meeting the two-way transmission flow requirements of uniform gas inflow, liquid outflow and non-interfering gas-liquid flow, and the like. And the use requirements of the proton exchange membrane fuel cell are well met.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen fuel cells, and in particular to a bipolar plate and a manufacturing method thereof, and a fuel cell. Background Art

[0002] The proton exchange membrane fuel cell (PEMFC) commonly used in hydrogen fuel cells is a power generation device that uses hydrogen as fuel and directly converts the chemical energy in the fuel (hydrogen and oxygen) into electrical energy through electrochemical reactions. It has the advantages of high energy conversion efficiency, zero emissions, and no noise. At present, the basic structure of the proton exchange membrane fuel cell mainly includes four parts: bipolar plate (also known as collector plate), diffusion layer, catalyst layer and proton exchange membrane. Among them, the bipolar plate plays the role of supporting electrodes, providing channels for transporting hydrogen and oxygen, discharging water generated by electrochemical reactions, connecting electrodes with external circuits, and dissipating heat in the proton exchange membrane fuel cell; the diffusion layer provides a corresponding channel for gas to diffuse from the bipolar plate to the catalyst layer; the catalyst layer is mainly made of nano-metal platinum material; the proton exchange membrane has the functions of preventing the gas between the cathode and the anode from communicating, having good conductivity for hydrated protons and blocking the passage of electrons, and the wet proton exchange membrane is the electrolyte of the fuel cell. In summary, the above four parts of the proton exchange membrane fuel cell can realize the electrochemical reaction of hydrogen and oxygen transmitted from two different directions on the proton exchange membrane, and the generated water (gas) is discharged through the diffusion layer and the flow layer.

[0003] In the existing proton exchange membrane fuel cell structure, the bipolar plate mainly adopts a graphite bipolar plate, a metal bipolar plate or a composite bipolar plate structure, wherein: ① Graphite bipolar plates are processed and formed from graphite materials, which have the advantages of high thermal conductivity and electrical conductivity, stable chemical properties, and mature manufacturing technology; however, graphite bipolar plates have low mechanical strength, large mass and volume, poor machinability, and high processing costs, which restricts their development.

[0004] ② Metal bipolar plates are usually made of stainless steel materials through rolling or stamping processes. They have the advantages of excellent mechanical properties, high thermal conductivity and electrical conductivity, easy processing and low production cost, good structural durability, and resistance to impact and vibration. However, metal bipolar plates have poor corrosion resistance in acidic reaction environments and require surface modification and anti-corrosion treatment.

[0005] ③ The composite bipolar plate is made of a composite of graphite and polymer materials. It has the advantages of good corrosion resistance, small size and light weight. However, the composite bipolar plate has poor mechanical strength, low electrical conductivity, a relatively complicated manufacturing process, and relatively poor sealing, which also restricts its development.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] In order to overcome the above-mentioned defects, the present invention provides a bipolar plate and a manufacturing method thereof, and a fuel cell. The manufacturing method is simple and reasonable, and can realize automated, large-scale, and efficient composite sintering preparation. The obtained bipolar plate has the characteristics of good thermal conductivity, high electrical conductivity, high mechanical strength, high air tightness, and meets the bidirectional transmission flow requirements of "gas flowing in uniformly, liquid flowing out, and gas and liquid flowing without interfering with each other", which well meets the use requirements of proton exchange membrane fuel cells.

[0008] The technical solution adopted by the present invention to solve the technical problem is: a method for manufacturing a bipolar plate, comprising the following manufacturing steps: S1: Selecting a metal powder having electrical and thermal conductivity, mixing the metal powder with a binder, a solvent and a pore-forming agent, and then subjecting the mixture to high temperature treatment to obtain a functional layer having a porous network structure; S2: Selecting an ultra-thin metal layer, stacking the ultra-thin metal layer and the functional layer, and then sintering them at a high temperature to obtain the bipolar plate.

[0009] As a further improvement of the present invention, in the above S1, the specific method for making the functional layer is: S11: 50% to 80% of metal powder, 10% to 20% of binder, 5% to 10% of solvent and 5% to 20% of pore-forming agent are mixed uniformly by weight to prepare a slurry; wherein the metal powder is fine nickel powder or ultrafine nickel powder with a particle size of 0.5 to 50 μm; S12: evenly coating the obtained slurry to form a blank film material, and then sintering the obtained blank film material at high temperature to obtain the functional layer; wherein the processing conditions of the high temperature sintering are: using nitrogen as the protective gas and hydrogen as the reducing gas; sintering at 750°C to 1000°C for 60 to 120 minutes.

[0010] As a further improvement of the present invention, in the above S11, the binder is at least one of dextrin and α-starch; the solvent includes deionized water and an organic solvent, and the organic solvent is at least one of propanol, isopropanol, acetone, toluene, xylene, terpineol, triethanolamine, dimethylformamide, isophorone and dibasic acid ester; the pore-forming agent is at least one of polyethylene and polypropylene.

[0011] As a further improvement of the present invention, the functional layer is a sheet structure with a thickness of 40 to 120 μm, the holes in the functional layer are three-dimensional through holes with an average pore size of micro-nano level, and the porosity of the functional layer is 40% to 95%.

[0012] As a further improvement of the present invention, the average pore diameter of the three-dimensional through holes in the functional layer is 2 to 200 μm.

[0013] As a further improvement of the present invention, in the above S2, the ultra-thin metal layer adopts a stainless steel sheet with a thickness of 20 to 40 μm; the specific processing method of the high-temperature sintering is: after cutting and shaping the functional layer and the ultra-thin metal layer, they are stacked and placed in a graphite mold; then the graphite mold carrying the functional layer and the ultra-thin metal layer is placed in a reduction furnace for high-temperature sintering treatment at a sintering temperature of 850°C to 1000°C for 15 to 60 minutes, the bipolar plate is obtained.

[0014] The present invention also provides a bipolar plate, which is manufactured using the bipolar plate manufacturing method described in the present invention.

[0015] As a further improvement of the present invention, the functional layer and the ultra-thin metal layer are each configured as one.

[0016] As a further improvement of the present invention, the functional layers are configured in two, and the ultra-thin metal layer is configured in one and is fixedly sandwiched between the two functional layers.

[0017] The present invention also provides a fuel cell, comprising a battery unit, wherein the battery unit is provided with a proton exchange membrane, a catalyst layer, a diffusion layer and a bipolar plate stacked in sequence from the inside to the outside, and the bipolar plate adopts the bipolar plate as described in the present invention.

[0018] The beneficial effects of the present invention are: 1) Through technological innovation, the bipolar plate prepared by the present invention has excellent connectivity, capillary properties and ultra-thin characteristics, which not only well meets the design requirements of the bipolar plate for "uniform gas inflow, liquid outflow (precipitation), and non-interference between gas and liquid flow", but also is beneficial to the physical and chemical conversion and corresponding electrochemical reaction of hydrogen fuel cells; and because of the ultra-thin structure, the power of fuel cells under the same size conditions can be greatly improved, or the geometric dimensions of fuel cells under the same power conditions can be greatly reduced. 2) The functional layer preparation method provided by the present invention can realize the adjustable size of the pore size and porosity in the functional layer, which greatly improves the processing convenience and flexibility of the functional layer and expands the application range of the functional layer / bipolar plate. 3) The bipolar plate preparation method provided by the present invention is simple and reasonable, and can realize automated, large-scale and efficient processing and production (specifically composite sintering preparation and production), which is conducive to promotion and implementation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a flow chart of the method for manufacturing the bipolar plate according to Example 1 of the present invention; Figure 2 Schematic diagram of the cross-sectional structure of the bipolar plate obtained in Example 1 of the present invention; Figure 3 Schematic diagram of the cross-sectional structure of the bipolar plate obtained in Example 3 of the present invention; Figure 4 It is a schematic diagram of a partial cross-sectional structure of a fuel cell according to Embodiment 4 of the present invention; Figure 5 It is a schematic diagram of the partial cross-sectional structure of the fuel cell described in Example 5 of the present invention.

[0020] Combined with the attached drawings, the following description is given: 1. Bipolar plate; 10. Functional layer; 11. Ultra-thin metal layer; 2. Diffusion layer; 3. Catalytic layer; 4. Proton exchange membrane. DETAILED DESCRIPTION

[0021] The present application is further described in detail below in conjunction with specific embodiments, but the present application is not limited to the following embodiments.

[0022] The present application provides a bipolar plate and a method for making the same, and a fuel cell. The method for making the bipolar plate is simple and reasonable, and can realize automated, large-scale, and efficient processing and production. The obtained bipolar plate has the characteristics of good thermal conductivity, high electrical conductivity, high mechanical strength, high air tightness, and meeting the bidirectional transmission flow requirements of "uniform gas inflow, liquid outflow (precipitation), and non-interference between gas and liquid flow", which well meets the use requirements of proton exchange membrane fuel cells. The reason for this is that the present application optimizes and innovates the structure and manufacturing method of the bipolar plate, as described below: Embodiment 1:

[0023] Please refer to the attached Figure 1 As shown, this embodiment 1 provides a method for manufacturing a bipolar plate, comprising the following manufacturing steps: S1: Select metal powder with electrical and thermal conductivity, mix the metal powder with a binder, a solvent and a pore-forming agent, and then perform high-temperature treatment to obtain a functional layer 10 with a porous network structure.

[0024] Specifically, the functional layer 10 is preferably manufactured by: S11: 55 kg of metal powder (nickel powder with a particle size of 10 μm), 18 kg of binder (α-starch), 3 kg of deionized water, 7 kg of organic solvent (dimethylformamide DMF) and 17 kg of pore-forming agent (polypropylene) are mixed uniformly to prepare a slurry.

[0025] Note: ① In the above-mentioned slurry raw material formula, the nickel powder has excellent electrical and thermal conductivity. The nickel powder is used as the main material to prepare the functional layer 10, which can well meet the requirements of the bipolar plate product for electrical and thermal conductivity; the solvent is used to dissolve the binder and disperse the nickel powder and the pore former; the binder is used to bond the nickel powder and the pore former; the pore former is used to generate through holes in the structure of the functional layer 10. ② The above-mentioned slurry raw material formula is only a preferred embodiment for preparing the functional layer 10 in this embodiment 1. This application is not limited to the above-mentioned raw material formula in practical application, and other additives can be added according to product design requirements. ③ In this embodiment 1, the nickel material can be processed by an atomization powder making process to obtain the nickel powder. The atomization powder making process is a powder preparation method in which a molten fluid (metal or alloy liquid) is atomized by rapid jetting, the metal or alloy liquid is formed into fine droplets, and then rapidly condensed into solid powder; it belongs to the conventional technical means in the field of metal powder making, so it will not be described in detail here. Of course, in addition to using the atomization powder making process to make nickel powder, the chemical powder making process (or other powder making processes) can also be used to make nickel powder. As is well known, ultrafine carbonyl nickel powder can be obtained by using the chemical powder making process. This is also a conventional technical means in the field of metal powder making, so it will not be described in detail here.

[0026] S12: The obtained slurry is evenly coated to form a green sheet, and then the green sheet is subjected to high temperature sintering to obtain the functional layer 10. The processing conditions for the high temperature sintering are: nitrogen is used as the protective gas, hydrogen is used as the reducing gas, and sintering is performed at 900° C. for 80 minutes.

[0027] Note: ① When performing the above-mentioned slurry coating process, the slurry can be evenly coated on a carrier such as ceramic or glass using a conventional coating process to form the blank film material. ② According to processing requirements, before the blank film material is subjected to high-temperature sintering, the blank film material can also be dried to dry the solvent and improve the sintering speed and sintering quality.

[0028] Based on the slurry raw material formula and high temperature sintering process used in this embodiment 1, the functional layer 10 having an overall sheet-like shape and a porous network structure at a microscopic level can be obtained. After testing, the thickness of the functional layer 10 is 60 μm, the average pore size of the pores in the functional layer 10 is 35 μm, and the porosity is 90%. It can be understood that the functional layer 10 has the characteristics of ultra-thin structure, excellent three-dimensional connectivity and capillary properties.

[0029] From the above, it can be seen that, on the one hand, by means of the three-dimensional through-hole structure (which can achieve excellent three-dimensional connectivity) and capillary properties of the functional layer 10, it is possible to achieve a relatively uniform flow of gas into the functional layer 10 and liquid out of the functional layer 10, while ensuring that the two-way flow of gas into the functional layer 10 and liquid out of the functional layer 10 do not interfere with each other, thereby well meeting the design requirements of the bipolar plate and being beneficial to the chemical and physical conversion of hydrogen fuel cells and the corresponding electrochemical reactions; on the other hand, by means of the ultra-thin structure of the functional layer 10, it is possible to provide strong technical support for the ultra-thin overall structure of the bipolar plate, thereby greatly improving the power of the fuel cell under the same size conditions, or greatly reducing the geometric dimensions of the fuel cell under the same power conditions.

[0030] S2: Selecting an ultra-thin metal layer 11, and stacking the ultra-thin metal layer 11 and the functional layer 10 and then sintering them at a high temperature, so as to obtain the bipolar plate.

[0031] In this embodiment 1, the ultra-thin metal layer 11 is mainly used to provide support and reinforcement to the functional layer 10, so as to further improve the mechanical strength of the bipolar plate as a whole. Based on the above preferred implementation structure of the functional layer 10, the ultra-thin metal layer 11 preferably uses a stainless steel sheet with a thickness of 20 μm, which not only plays a good supporting and reinforcing role, but also further realizes the ultra-thinness of the overall structure of the bipolar plate.

[0032] In addition, the specific processing method used in the present embodiment 1 for high temperature sintering of the functional layer 10 and the ultra-thin metal layer 11 is: S21: In this embodiment 1, the functional layer 10 and the ultra-thin metal layer 11 are configured as one according to product design requirements; then the functional layer 10 and the ultra-thin metal layer 11 are cut and shaped so that the sizes of the functional layer 10 and the ultra-thin metal layer 11 meet the product design requirements; and then the shaped functional layer 10 and the ultra-thin metal layer 11 are placed in a graphite mold in a stacked and aligned manner.

[0033] S22: placing the graphite mold carrying the functional layer 10 and the ultra-thin metal layer 11 into a reduction furnace for high-temperature sintering, and the specific processing conditions of the high-temperature sintering are optimized as follows: using nitrogen as the protective gas and hydrogen as the reducing gas; sintering at 900° C. for 45 minutes; after the high-temperature sintering and cooling are completed, the bipolar plate with a two-layer structure is obtained, which can be referred to in the attached Figure 2 shown.

[0034] It can be understood that, through the above-mentioned optimized high-temperature sintering process, the functional layer 10 and the ultra-thin metal layer 11 can be very firmly combined.

[0035] S3: Performing conventional finished product testing process on the bipolar plate to complete the production of the bipolar plate finished product required subsequently.

[0036] From the above, it can be seen that the manufacturing method of the bipolar plate described in this embodiment 1 is simple, reasonable and novel, and can realize automated and large-scale production. The obtained bipolar plate has excellent three-dimensional through-hole structure, excellent capillary performance and ultra-thin structure, etc., which well meets the design requirements of the bipolar plate. Embodiment 2:

[0037] The present embodiment 2 also provides a method for manufacturing a bipolar plate, and compared with the embodiment 1, the method for manufacturing a bipolar plate described in the present embodiment 2 has the following differences: ① When manufacturing the functional layer 10, the slurry raw material formula used in the present embodiment 2 and the processing conditions for high-temperature sintering of the blank film material are different from those in the embodiment 1; ② The processing conditions used in the present embodiment 2 for high-temperature sintering of the functional layer 10 and the ultra-thin metal layer 11 are different from those in the embodiment 1.

[0038] Specifically, regarding the above-mentioned distinction ①; In the preparation of the functional layer 10 in this embodiment 2, ① the slurry raw material formula used is: 65Kg of metal powder (nickel powder with a particle size of 20μm), 15Kg of binder (dextrin), 2Kg of deionized water, 6Kg of organic solvent (dimethylformamide DMF) and 12Kg of pore-forming agent (polyethylene) are mixed evenly to prepare the slurry. ② The slurry coating process used is the same as that in embodiment 1, but the film thickness of the obtained rough film material is different, which is determined according to the design requirements. ③ The high-temperature sintering processing conditions for the rough film material are: nitrogen is used as the protective gas, hydrogen is used as the reducing gas; sintering at 800℃ for 100min.

[0039] Based on the slurry raw material formula and high temperature sintering processing conditions used in this embodiment 2, this embodiment 2 also obtains the functional layer 10 having an overall sheet-like appearance and a porous network structure at a microscopic level. After testing, the thickness of the functional layer 10 obtained in this embodiment 2 is 80 μm, the average pore size of the pores in the obtained functional layer 10 is 40 μm, and the porosity is 80%. It can be understood that the functional layer 10 obtained in this embodiment 2 also has the characteristics of ultra-thin structure, excellent three-dimensional connectivity, and excellent capillary properties.

[0040] Regarding the above-mentioned distinction ②; In this embodiment 2, according to the product design requirements, the functional layer 10 and the ultra-thin metal layer 11 are configured as one, and the material selection and thickness of the ultra-thin metal layer 11 are the same as those in embodiment 1. In this embodiment 2, after the shaped functional layer 10 and the ultra-thin metal layer 11 are placed in a graphite mold in a stacked and aligned manner, the graphite mold carrying the functional layer 10 and the ultra-thin metal layer 11 is placed in a reduction furnace for high-temperature sintering, and the processing conditions of the high-temperature sintering are optimized as follows: nitrogen is selected as the protective gas, and hydrogen is selected as the reducing gas; sintering at 850°C for 60 minutes; after completing the high-temperature sintering and cooling, the bipolar plate with a two-layer structure is obtained. It can be understood that through the above-mentioned optimized high-temperature sintering process, the functional layer 10 and the ultra-thin metal layer 11 in this embodiment 2 are also very firmly combined.

[0041] It can also be seen from the above that the manufacturing method of the bipolar plate described in this embodiment 2 is simple and reasonable, and can realize automated and large-scale production. The obtained bipolar plate has excellent three-dimensional through-hole structure, excellent capillary performance and ultra-thin structure, which well meets the design requirements of the bipolar plate. Embodiment 3:

[0042] This embodiment 3 also provides a method for manufacturing a bipolar plate, and compared with embodiment 1, the method for manufacturing a bipolar plate described in this embodiment 3 has the following differences: ① When manufacturing the functional layer 10 in this embodiment 3, the slurry raw material formula used is different from that in embodiment 1; ② The configuration quantity and arrangement method of the functional layer 10 and the ultra-thin metal layer 11 in this embodiment 3 are different from those in embodiment 1.

[0043] Specifically, regarding the above-mentioned distinction ①; In the present embodiment 3, when preparing the functional layer 10, the slurry raw material formula used is: 75 kg of metal powder (nickel powder with a particle size of 10 μm), 12 kg of binder (α-starch), 2 kg of deionized water, 3 kg of organic solvent (dimethylformamide DMF) and 8 kg of pore-forming agent (polyethylene) are mixed evenly to prepare a slurry.

[0044] Based on the slurry raw material formula used in this embodiment 3, combined with the same slurry coating process and high-temperature sintering process as in embodiment 1, this embodiment 3 can also produce the functional layer 10 with an overall sheet-like appearance and a porous network structure at a microscopic level. After testing, the thickness of the functional layer 10 obtained in this embodiment 3 is 60 μm, the average pore size of the pores in the obtained functional layer 10 is 30 μm, and the porosity is 70%. It can be understood that the functional layer 10 obtained in this embodiment 3 also has the characteristics of ultra-thin structure, excellent three-dimensional connectivity and excellent capillary properties.

[0045] Regarding the above-mentioned distinction ②; According to product design requirements, in this embodiment 3, the functional layer 10 is configured as two, and the structural characteristics (such as porosity, etc.) of the two functional layers 10 are kept consistent; the ultra-thin metal layer 11 is configured as one, and the ultra-thin metal layer 11 is preferably a stainless steel sheet with a thickness of 30 μm.

[0046] Based on the above configuration number of the functional layer 10 and the ultra-thin metal layer 11, in this embodiment 3, after the shaped functional layer 10 and the ultra-thin metal layer 11 are placed in a graphite mold in a stacked and aligned manner (Note: the ultra-thin metal layer 11 is sandwiched between two functional layers 10), the graphite mold carrying the functional layer 10 and the ultra-thin metal layer 11 is placed in a reduction furnace for the same high-temperature sintering process as in embodiment 1, that is, the bipolar plate with a three-layer structure is obtained. Please refer to the attached Figure 3 As shown, it can be understood that the functional layer 10 and the ultra-thin metal layer 11 in this embodiment 3 are also very firmly combined.

[0047] It can be seen from the above that the method for manufacturing the bipolar plate described in Example 3 is also simple and reasonable, and can realize automated and large-scale production. The obtained bipolar plate has excellent three-dimensional through-hole structure, excellent capillary performance and ultra-thin structure, which well meets the design requirements of the bipolar plate.

[0048] In addition, it is noted that the reason why two functional layers 10 are configured in the bipolar plate structure in this embodiment 3 is to enhance the flexibility and convenience of the integrated assembly of the proton exchange membrane fuel cell, which can be seen in the following embodiment 5. Embodiment 4:

[0049] Please refer to the attached Figure 4 As shown, this embodiment 4 provides a fuel cell, which includes a group of battery cells, wherein the battery cells include a proton exchange membrane 4, a catalyst layer 3, a diffusion layer 2 and a bipolar plate 1 stacked in sequence from the inside to the outside, wherein the bipolar plate 1 adopts the bipolar plate structure as described in Example 1, so it is not repeated here; the diffusion layer 2, the catalyst layer 3 and the proton exchange membrane 4 all adopt the conventional structure in the existing proton exchange membrane fuel cell, such as: the diffusion layer 2 adopts carbon cloth or carbon paper, the catalyst layer 3 is mainly made of nano-metal platinum material, and the proton exchange membrane 4 adopts a non-fluorinated polymer proton exchange membrane, a fluorosulfonic acid proton exchange membrane or a Nafion membrane. Embodiment 5:

[0050] Please refer to the attached Figure 5As shown, this embodiment 5 provides a fuel cell, which includes a plurality of groups of battery cells connected in sequence, each group of the battery cells includes a proton exchange membrane 4, a catalyst layer 3, a diffusion layer 2 and a bipolar plate stacked in sequence from the inside to the outside, and each two adjacent groups of the battery cells share a bipolar plate, and the shared bipolar plate adopts the bipolar plate structure as described in embodiment 3; in addition, the two groups of the battery cells located on the outermost sides are respectively defined as outer battery cells, and the two bipolar plates located on the opposite sides of the two groups of the outer battery cells respectively adopt the bipolar plate structure as described in embodiment 1. In addition, the diffusion layer 2, the catalyst layer 3 and the proton exchange membrane 4 all adopt the conventional structure in the existing proton exchange membrane fuel cell, such as: the diffusion layer 2 is made of carbon cloth or carbon paper, the catalyst layer 3 is mainly made of nano metal platinum material, and the proton exchange membrane 4 is a non-fluorinated polymer proton exchange membrane, a fluorosulfonic acid type proton exchange membrane or a Nafion membrane.

[0051] In summary, the bipolar plate manufacturing method described in the present application is simple and reasonable, and can realize automated, large-scale and efficient processing and production. Moreover, the obtained bipolar plate has the characteristics of good thermal conductivity, high electrical conductivity, high mechanical strength, high air tightness, and meets the bidirectional transmission flow requirements of "uniform gas inflow, liquid outflow (precipitation), and non-interference between gas and liquid flow", which well meets the use requirements of proton exchange membrane fuel cells.

[0052] Many specific details are described in the above description to facilitate a full understanding of the present invention. However, the above description is only a preferred embodiment of the present invention. The present invention can be implemented in many other ways different from those described herein, so the present invention is not limited to the specific implementation disclosed above. At the same time, any person familiar with the art can make many possible changes and modifications to the technical solution of the present invention using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A method for manufacturing a bipolar plate, characterized in that: The production steps include: S1: 50% to 80% of metal powder, 10% to 20% of binder, 5% to 10% of solvent and 5% to 20% of pore-forming agent are mixed uniformly by weight to prepare a slurry; wherein the metal powder is fine nickel powder or ultrafine nickel powder with a particle size of 0.5 to 50 μm; the binder is at least one of dextrin and α-starch; the pore-forming agent is at least one of polyethylene and polypropylene; The obtained slurry is then evenly coated to form a green sheet, and the green sheet is subjected to high temperature sintering to obtain a functional layer (10) with a porous network structure; wherein the processing conditions for the high temperature sintering are: nitrogen is used as a protective gas, hydrogen is used as a reducing gas; and sintering is performed at 750°C to 1000°C for 60 to 120 minutes; S2: A stainless steel sheet with a thickness of 20 to 40 μm is selected as the ultra-thin metal layer (11), and the ultra-thin metal layer (11) and the functional layer (10) are cut and shaped, and then stacked and placed in a graphite mold; then the graphite mold carrying the functional layer (10) and the ultra-thin metal layer (11) is placed in a reduction furnace for high-temperature sintering treatment at a sintering temperature of 850° C. to 1000° C. for 15 to 60 minutes, thereby obtaining the bipolar plate.

2. The method for manufacturing a bipolar plate according to claim 1, characterized in that: In the above S1, the solvent includes deionized water and an organic solvent, and the organic solvent is at least one of propanol, isopropanol, acetone, toluene, xylene, terpineol, triethanolamine, dimethylformamide, isophorone and dibasic acid ester.

3. The method for manufacturing a bipolar plate according to claim 1, characterized in that: The functional layer (10) is a sheet structure with a thickness of 40 to 120 μm, the pores in the functional layer (10) are three-dimensional through holes with an average pore size of micro-nanoscale, and the porosity of the functional layer (10) is 40% to 95%.

4. The method for manufacturing a bipolar plate according to claim 3, characterized in that: The average pore size of the three-dimensional through holes in the functional layer (10) is 2 to 200 μm.

5. A bipolar plate, characterized in that: The bipolar plate is manufactured by the manufacturing method of any one of claims 1 to 4.

6. The bipolar plate according to claim 5, characterized in that: The functional layer (10) and the ultra-thin metal layer (11) are each configured as one.

7. The bipolar plate according to claim 5, characterized in that: The functional layers (10) are configured as two, and the ultra-thin metal layer (11) is configured as one and is fixedly sandwiched between the two functional layers (10).

8. A fuel cell, characterized in that: The battery cell comprises a proton exchange membrane (4), a catalyst layer (3), a diffusion layer (2) and a bipolar plate (1) which are stacked in sequence from the inside to the outside, wherein the bipolar plate (1) is the bipolar plate as claimed in claim 5.

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