Titanium-nickel-steel composite plate for hydrogen production by electrolysis of water and manufacturing method

Abstract

The application discloses a titanium-nickel-steel composite plate for a water electrolysis hydrogen production bipolar plate, which comprises an upper layer, an intermediate layer and a lower layer arranged in sequence, wherein the upper layer is a stainless steel plate layer, the intermediate layer is a nickel material layer, and the lower layer is a titanium plate layer. The titanium-nickel-steel composite plate for the water electrolysis hydrogen production bipolar plate has the corrosion resistance of titanium, the high strength (the tensile strength is up to 650 MPa) of alloy steel, and the manufacturing cost is greatly reduced (the cost of the titanium-nickel-steel composite plate is 41 yuan / kg to 83 yuan / kg, compared with 120 yuan / kg of pure titanium as the bipolar plate).

Description

Technical Field

[0001] This invention relates to the field of bipolar plates for hydrogen production by water electrolysis and their preparation technology, specifically to a titanium-nickel-steel composite plate for hydrogen production by water electrolysis and its manufacturing method. Background Technology

[0002] Hydrogen is considered one of the most promising, green, and clean energy sources. Hydrogen-to-electricity conversion offers high efficiency, hydrogen has a high energy density and is relatively easy to store, and the conversion of hydrogen into electricity has the potential for large-scale application. PEM (Proton Exchange Membrane) hydrogen production uses wind, solar, or electrical energy to electrolyze pure water to produce hydrogen. Its basic process involves water undergoing hydrolysis at the positive electrode, hydrogen ions passing through an ordered membrane electrode to the negative electrode, electrons traveling from the positive to the negative electrode via an external circuit, and the hydrogen ions combining with electrons at the negative electrode to generate hydrogen gas. This method uses pure water electrolysis, avoiding potential environmental pollution and is environmentally friendly. The low resistance and gas permeability of the proton exchange membrane result in high current density, operating efficiency, and gas purity. It also features a fast dynamic response, adapting to the fluctuations in renewable energy power generation.

[0003] The PEM electrolyzer mainly consists of an anode end plate, a cathode end plate, an anode-cathode diffusion layer, an anode-cathode catalyst layer, and a proton exchange membrane. Figure 1 The anode and cathode plates together are called bipolar plates, which are made of titanium plates approximately 1.0 mm thick. Titanium has a strong affinity for oxygen; in air or oxygen-containing media, a dense, strongly adherent, and highly inert oxide film forms on the titanium surface, protecting the titanium substrate from corrosion. Even if mechanical wear occurs, it quickly self-heals or regenerates. Because of these properties, titanium is ideally suited for manufacturing PEM bipolar plates. To achieve higher hydrogen production rates, PEM electrolyzers are typically composed of multiple individual electrolyzers stacked in series, resulting in a large demand for titanium plates for bipolar plates. Moreover, because titanium is a precious metal, its cost is relatively high.

[0004] To address the problems existing in the prior art, this invention provides a titanium-nickel-steel composite plate for hydrogen production bipolar plates via water electrolysis and a manufacturing method thereof. The resulting titanium-nickel-steel composite plate not only possesses the corrosion resistance of titanium but also the high strength of alloy steel, while significantly reducing manufacturing costs. These properties make the titanium-nickel-steel composite plate more suitable as a material for manufacturing PEM bipolar plates. Summary of the Invention

[0005] The purpose of this invention is to provide a titanium-nickel-steel composite plate for bipolar plates used in water electrolysis for hydrogen production and a method for manufacturing the same.

[0006] The present invention relates to a titanium-nickel-steel composite plate for a bipolar plate used in water electrolysis for hydrogen production and a method for manufacturing the same.

[0007] The resulting titanium-nickel-steel composite plate not only possesses the corrosion resistance of titanium but also the high strength of alloy steel, while significantly reducing manufacturing costs.

[0008] A titanium-nickel-steel composite plate for bipolar plates in water electrolysis for hydrogen production, comprising the following components arranged sequentially:

[0009] upper layer;

[0010] Intermediate layer;

[0011] Lower layer;

[0012] in,

[0013] The top layer is a stainless steel plate, the middle layer is a nickel material layer, and the bottom layer is a titanium plate.

[0014] As a further improvement to this design, the upper layer is a 304 stainless steel plate.

[0015] According to claim 1, the titanium-nickel-steel composite plate for bipolar plate of water electrolysis hydrogen production is characterized in that the thickness of the upper stainless steel plate layer is a and the thickness of the lower titanium plate layer is b, satisfying the quantitative relationship: a:b=(1~10):1.

[0016] As a further improvement to this scheme, the thickness of the intermediate nickel material layer is 0.1 to 0.5 mm.

[0017] A method for manufacturing a titanium-nickel-steel composite plate for a bipolar plate used in water electrolysis for hydrogen production, characterized by comprising the following preparation steps:

[0018] Surface treatment prior to preparation of S1 composite preform

[0019] Surface treatment is performed on the composite surfaces between the materials;

[0020] Preparation of S2 composite preform

[0021] A composite billet 1 is prepared by combining titanium, nickel, and steel. Then, two composite billets 1 are stacked together to form a single composite billet.

[0022] and,

[0023] A layer of graphite powder is placed between the composite blanks, and the stacking order is as follows:

[0024] Titanium-nickel-steel;

[0025] Graphite powder layer;

[0026] Steel-nickel-titanium;

[0027] The composite blank 1 and the composite blank 2 are fixed by welding.

[0028] S3 performs vacuum treatment on the composite preform.

[0029] Vacuum degree reaches 10 -1 Once the vacuum level reaches the required Pa and the required vacuum level is achieved, the vacuum valve will be closed and sealed.

[0030] S4 heats the composite billet to 1000-1200℃, holds it at that temperature until the temperature inside and outside the composite billet is uniform, and then hot rolls it into a composite coil or sheet with a thickness of 2.0-6.0mm.

[0031] In this step, the interface of the (titanium-nickel-steel) composite material after hot rolling achieves metallurgical bonding due to extrusion, deformation, atomic diffusion, etc., and becomes a complete whole.

[0032] S5 processes the head and tail of the cooled steel plate and trims the edges, removing the welding material welded to the edge during the composite billet process. At this point, the composite steel strip separates from the graphite into two independent composite steel strips.

[0033] S6 removes the oxide scale from the composite strip through processes such as shot blasting and then cold rolls it to the required thickness;

[0034] S7 involves continuously annealing the cold-rolled composite strip at a temperature of 600–700°C.

[0035] After S8 annealing, a titanium-nickel-steel composite plate is obtained, wherein the titanium side of the titanium-nickel-steel composite plate can be used as the flow channel of the bipolar plate.

[0036] As a further improvement to this scheme, the specific surface treatment method of the composite surface in S1 is as follows: the interface of the composite material to be processed is made flat and smooth by milling and grinding, and the metallic color is fully exposed. Then, foreign matter on the flat surface is removed by acetone or alcohol, and the sides are sealed by welding to obtain the first composite blank.

[0037] As a further improvement to this scheme, an air extraction hole is provided on the end face of the composite blank one.

[0038] As a further improvement to this scheme, in S6, the required thickness after cold rolling is 1.0 to 3.0 mm.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] Compared with the prior art, the titanium-nickel-steel composite plate and its manufacturing method for a bipolar plate used in water electrolysis for hydrogen production according to the present invention have the following advantages:

[0041] 1) In this invention, one side of the composite plate is a 304 stainless steel plate, and the other side is a titanium plate, with a pure nickel layer between the steel and titanium. The thickness ratio of steel to titanium is 1 to 10:1, with nickel as the intermediate layer. The actual thickness of each layer in the composite plate can be adjusted as needed. A higher proportion of steel results in higher costs, but a thin titanium layer is prone to cracking. The 304 stainless steel substrate on one side of the steel-titanium composite plate has high structural strength and certain corrosion resistance, while the pure titanium on the other side has good corrosion resistance, meeting the high corrosion resistance requirements of the bipolar plate surface.

[0042] 2) In this invention, 304 stainless steel plate has high strength and certain corrosion resistance, ensuring that the bipolar plate made from the composite plate has higher strength and basic rust resistance than the pure titanium bipolar plate. The pure titanium layer needs a certain thickness to ensure good corrosion resistance on this side, but increasing the proportion of pure titanium will significantly increase the cost of the composite plate. Nickel serves to separate the steel and titanium, preventing the formation of brittle steel-iron intermetallic compounds. Steel and titanium react at high temperatures to produce various intermetallic compounds. Steel and nickel are infinitely soluble, and the intermetallic compounds of nickel and titanium have a relatively certain degree of toughness.

[0043] 3) In this invention, a method for manufacturing a titanium-nickel-steel composite plate for a bipolar plate used in water electrolysis for hydrogen production involves stacking two composite blanks into one, with the stacking order being (titanium-nickel-steel) and (steel-nickel-titanium). A layer of graphite powder is evenly spread between the two layers, with a thickness sufficient to separate the metals on both sides. Both sides of the graphite must be steel; otherwise, the titanium and graphite will undergo a chemical reaction during subsequent production to produce brittle and hard titanium carbide. Then, the (titanium-nickel-steel) and (steel-nickel-titanium) plates are fixed together by welding to prevent delamination during hot rolling.

[0044] 4) The titanium-nickel-steel composite plate for the electrolytic hydrogen production bipolar plate of the present invention not only has the corrosion resistance of titanium, but also the high strength of alloy steel (tensile strength up to 650MPa), while the manufacturing cost is greatly reduced (the cost of titanium-nickel-steel composite plate is 41 yuan / kg to 83 yuan / kg, compared with 120 yuan / kg for pure titanium as a bipolar plate). Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the internal structure of a PEM electrolyzer;

[0046] Figure 2 This is a schematic diagram of the structure of a titanium-nickel-steel composite billet for the bipolar plate used in the electrolysis of water to produce hydrogen according to the present invention;

[0047] Figure 3 This is a schematic diagram of the structure of the composite billet (titanium-nickel-steel)-(graphite powder layer)-(steel-nickel-titanium) of the present invention;

[0048] Figure 4This is a schematic diagram of the structure of the air extraction hole on the end face of the composite blank of the present invention, which is sealed by welding on the side.

[0049] Explanation of reference numerals in the attached figures:

[0050] 11-Upper layer;

[0051] 12-Intermediate layer;

[0052] 13-Lower layer;

[0053] 20-Composite blank;

[0054] 21-Composite billet one;

[0055] 22-Graphite powder layer. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below with reference to embodiments:

[0057] The titanium-nickel-steel composite plate for the bipolar plate of water electrolysis hydrogen production of the present invention comprises, in sequence:

[0058] Upper layer 11;

[0059] Intermediate layer 12;

[0060] Lower layer 13;

[0061] in,

[0062] The upper layer 11 is a stainless steel plate layer, the middle layer 12 is a nickel material layer, and the lower layer 13 is a titanium plate layer.

[0063] Specifically, it includes the following preparation steps:

[0064] Two composite billets 21 are stacked together to form a single composite billet 20, with the stacking order being (titanium-nickel-steel) and (steel-nickel-titanium). A thin layer of graphite powder 22 is evenly spread between the two layers, with a thickness just enough to separate the two metal (stainless steel plate layers) on both sides. Then, the (titanium-nickel-steel) and (steel-nickel-titanium) layers are fixed together using conventional welding methods. The composite billet is then subjected to vacuum treatment, achieving a vacuum level of 10. -1 Once the required vacuum level is reached, the vacuum valve will be closed and sealed.

[0065] The composite billet is heated to 1100℃ and held at that temperature until the internal and external temperatures of the composite billet are uniform. Then, it is hot-rolled into a composite strip with a thickness of 2.5mm. After hot rolling, the interface of the (titanium-nickel-steel) composite material achieves metallurgical bonding due to extrusion, deformation, and atomic diffusion, becoming a complete whole. After cooling, the ends of the steel plate are trimmed, and the composite steel strip is separated from the graphite layer into two independent (titanium-nickel-steel) and (steel-nickel-titanium) composite steel strips.

[0066] The composite strip is descaled using processes such as shot blasting and then cold-rolled to a thickness of 1.0 mm. The cold-rolled composite strip is then continuously annealed at 650℃. After annealing, the titanium-nickel-steel composite plate is ready for use, with the titanium side serving as the anode flow channel for the bipolar plate.

[0067] Examples 1-5, Comparative Examples 1-3:

[0068] As shown in Table 1, 304 stainless steel with a thickness of 20 mm, pure titanium with thicknesses of 2 mm, 5 mm, 10 mm, 15 mm, and 20 mm, and pure nickel with a thickness of 0.2 mm were used as composite materials for composites. The width and length of the materials were 250 mm and 1000 mm, respectively, which are Examples 1 to 5.

[0069] Meanwhile, 304 stainless steel with a thickness of 2mm, titanium with a thickness of 2mm, and nickel with a thickness of 0.2mm were used as reference objects, namely Comparative Examples 1 to 3.

[0070] The composite materials are stacked in the order of titanium-nickel-steel. Before stacking, all composite surfaces are milled and ground to make the interfaces of the composite materials smooth and flat, exposing the metallic color. Then, foreign matter on the smoothed surfaces is removed with acetone, and the sides are sealed by welding. Figure 3 As shown, an air extraction hole is left on the end face of the composite blank.

[0071]

[0072]

[0073] Table 2 shows that the tensile strength of the titanium-nickel-steel composite plates of Examples 1-5, stainless steel of Comparative Example 1, and titanium of Comparative Example 2 were tested. The results showed that the stainless steel of Comparative Example 1 had the highest tensile strength of 675 MPa, while the titanium of Comparative Example 2 had a tensile strength of 500 MPa. In Examples 1-5, as the steel-to-titanium thickness ratio changed from 10:1 to 1:1, the tensile strength gradually decreased from 650 MPa to 575 MPa, falling between that of steel and titanium. Furthermore, the higher the proportion of steel, the higher the tensile strength. This provides room for improvement in the PEM package electrolysis water production process, which requires structural weight reduction while simultaneously withstanding hydrogen pressure. The nickel of Comparative Example 3 had a tensile strength of 400 MPa; however, due to its very limited thickness proportion, its impact on structural strength was minimal.

[0074] The standard pitting potentials of the titanium-nickel-steel composite plates of Examples 1-5, stainless steel of Comparative Example 1, and titanium of Comparative Example 2 were tested. The results showed that the pitting potential on the steel side of the composite plate was similar to that of Comparative Example 1 (0.31V), with a variation range of 0.27-0.30V; the pitting potential on the titanium side was similar to that of Comparative Example 2 (1.53V), with a variation range of 1.49-1.53V. This indicates that the titanium side of the composite plate is suitable as the PEM anode.

[0075] The thickness of titanium in 1.0 mm cold-rolled steel strips from Examples 1-5 was tested. The results showed that the proportion of titanium in the steel sheet after cold rolling was basically consistent with the proportion of titanium in the billet assembly. As the steel-to-titanium thickness ratio changed from 10:1 to 1:1, the actual thickness of the titanium layer gradually increased from 0.09 mm to 0.5 mm. Based on this result, the thickness of the titanium layer can be reasonably configured according to needs in actual use.

[0076] Currently, the price of 304 stainless steel cold-rolled sheet is approximately RMB 15 / kg, cold-rolled titanium sheet is approximately RMB 120 / kg, and nickel sheet is approximately RMB 205 / kg. Based on the weight ratio of each material in the composite plate and adding a comprehensive composite cost of RMB 15 / kg, the calculated cost of the composite plate is shown in Table 2. It can be seen that as the steel-to-titanium thickness ratio changes from 10:1 to 1:1, the calculated cost from Examples 1 to 5 gradually increases from RMB 41 / kg to RMB 83 / kg, all significantly lower than that of pure titanium as the bipolar plate in Comparative Example 2. It can be observed that the higher the proportion of steel in the composite steel, the lower the cost; however, a too-thin titanium layer makes damage during processing and use possible.

[0077] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent modifications made using the present invention are within the patent protection scope of the present invention.

Claims

1. A method for manufacturing a titanium-nickel-steel composite plate for a bipolar plate used in water electrolysis for hydrogen production, characterized in that, The preparation steps include the following: S1 Surface treatment before the preparation of the composite blank: the surface of the composite surface between the materials is treated; S2 Preparation of the composite blank (20): titanium-nickel-steel is composited to obtain composite blank one (21), and two composite blanks one (21) are stacked into one composite blank (20). A graphite powder layer (22) is provided between the composite blank one (21) and the composite blank one (21). The stacking order is as follows: titanium-nickel-steel; graphite powder layer (22); steel-nickel-titanium; the composite blank one (21) and the composite blank one (21) are fixed by welding; S3 Vacuum treatment of the composite blank (20): the vacuum degree reaches more than 10-1 Pa. After the vacuum degree reaches the requirement, the air is evacuated. S4. Heat the composite billet to 1000-1200℃ and hold it until the temperature inside and outside the composite billet is uniform. Then, hot roll it into a composite coil or plate with a thickness of 2.0-6.0mm. S5. Trim the ends and edges of the cooled steel plate and remove the welding material welded to the edges during the composite billet process. At this time, the composite steel strip separates from the graphite into two independent composite steel strips. S6. Remove the oxide scale from the composite coil through processes such as shot blasting and cold roll it to the required thickness. S7. Continuously anneal the cold-rolled composite coil at a temperature of 600-700℃. S8. After annealing, a titanium-nickel-steel composite plate is obtained. The titanium side of the titanium-nickel-steel composite plate can be used as a flow channel for a bipolar plate. The titanium-nickel-steel composite plate includes, in sequence: an upper layer (11); a middle layer (12); and a lower layer (13); wherein the upper layer (11) is a stainless steel plate layer, the middle layer (12) is a nickel material layer, and the lower layer (13) is a titanium plate layer; The upper layer (11) is a 304 stainless steel plate layer.

2. The method for manufacturing the titanium-nickel-steel composite plate for the bipolar plate of water electrolysis hydrogen production according to claim 1, characterized in that, The thickness of the stainless steel plate layer in the upper layer (11) is a, and the thickness of the titanium plate layer in the lower layer (13) is b, satisfying the quantitative relationship: a:b=(1~10):

1.

3. The titanium-nickel-steel composite plate for bipolar plate in water electrolysis for hydrogen production and its manufacturing method according to claim 1, characterized in that, The thickness of the intermediate layer (12) nickel material layer is 0.1 to 0.5 mm.

4. The titanium-nickel-steel composite plate for bipolar plate in water electrolysis for hydrogen production and its manufacturing method according to claim 1, characterized in that, The specific surface treatment method for the composite surface in S1 is as follows: the interface of the composite material to be processed is flat and smooth by milling and grinding, and the metallic color is fully exposed. Then, foreign matter on the flat surface is removed by acetone or alcohol, and the side is sealed by welding to obtain composite blank one (21).

5. The titanium-nickel-steel composite plate for bipolar plate in water electrolysis for hydrogen production and its manufacturing method according to claim 1, characterized in that, An air extraction hole is provided on the end face of the composite blank (21).

6. The titanium-nickel-steel composite plate for bipolar plate in water electrolysis for hydrogen production and its manufacturing method according to claim 4, characterized in that, In S6, the required thickness after cold rolling is 1.0 to 3.0 mm.

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