Bipolar plate, preparation method and application

Abstract

The invention discloses a bipolar plate and a preparation method and application thereof.The bipolar plate comprises a net face, a supporting body, a main polar plate, a supporting body and a net face which are sequentially arranged in a stacked mode, the supporting body is obtained by sequentially arranging a plurality of metal wires or metal nets along the main polar plate, the projection of the metal wires or the metal nets in at least one direction is in a waveform shape, and the metal wires or the metal nets are arranged on the net face. And a runner structure is formed between the metal wires or the metal nets. The implementation of the application can solve the problems of poor consistency, high contact resistance, non-uniform gas-liquid flow, irreversible damage to an electrode catalytic material and the like existing in the mastoid pole plate.

Description

Technical Field

[0001] The present invention relates to the technical field of alkaline electrolyzers, and in particular to a bipolar plate, a preparation method and an application thereof. Background Art

[0002] Alkaline water electrolysis, one of the most mature large-scale hydrogen production technologies, is a crucial technical support for the development of the hydrogen energy industry. An alkaline electrolyzer primarily consists of end plates, anodes and cathodes, a separator, bipolar plates, seals, fasteners, and insulation. The bipolar plates separate the anodes and cathodes of adjacent cells, forming independent reaction chambers. This prevents mixing of oxygen generated at the anodes and hydrogen generated at the cathodes between adjacent cells, thus avoiding potential safety hazards such as explosions caused by gas mixing. Furthermore, the bipolar plates collect electrons from the anodes and conduct current to the cathodes of adjacent cells, ensuring an orderly flow of electrons throughout the electrolyzer's electrode system. This efficient current conduction is crucial for maintaining the electrolysis reaction, as it evenly distributes sufficient current to each cell's electrodes. Therefore, it is a key factor in ensuring that large-scale electrolysis reactions proceed synchronously and efficiently across all cells. Furthermore, the bipolar plates should also distribute the electrolyte and gaseous products, guiding the electrolyte evenly across the electrode surfaces. Once hydrogen and oxygen are generated on the electrode surfaces, they exit the reaction zone along gas channels on the bipolar plates and enter the collection system. The electrolyte is promoted to form a uniform liquid film on the electrode surface, avoiding local electrolyte concentrations that are too high or too low, thereby improving the efficiency of the electrolysis reaction. In addition, the gas flow channel can quickly discharge the generated gas, preventing gas accumulation on the electrode surface and affecting the subsequent electrolysis reaction.

[0003] The bipolar plates also provide mechanical support for the electrolyzer's overall structure. During assembly and operation, they withstand certain pressures and vibrations. Even in the presence of minor vibrations that may occur during transportation or operation, the bipolar plates prevent displacement or damage to internal components such as the electrodes, ensuring the proper functioning of the electrolyzer.

[0004] Mastoid plates, the most widely used bipolar plates in alkaline electrolyzers, offer numerous advantages, but they also have drawbacks. These include high stamping and mold-making costs, difficulty in compacting the chamber structure, the risk of flow channel blockage, low manufacturing precision, and poor long-term operational stability. For a 1000 Nm³ / h alkaline electrolyzer with a mastoid plate diameter of approximately 1.8-2 m, approximately 3,000 mastoids are required, and the overall stamping mold manufacturing cost can reach several million yuan. The mastoid structure forms relatively complex flow channels. During the electrolysis process, impurities in the electrolyte or solid particles produced by electrode reactions are more likely to accumulate in these complex flow channels, increasing the risk of flow channel blockage. Once the flow channels become blocked, uneven electrolyte distribution can occur, affecting sufficient contact between the electrodes and the electrolyte, increasing the internal resistance of the electrolyzer, reducing electrolysis efficiency, and potentially leading to localized overheating, impacting the normal operation and service life of the electrolyzer. Due to the complex manufacturing process of the mastoid plate, high manufacturing precision is required. In actual production, it's difficult to ensure that every mastoid plate has exactly the same parameters, such as shape, size, and distribution. Slight differences in these parameters can lead to performance differences between different mastoid plates, which in turn affects the performance consistency of the entire electrolyzer. During long-term operation, the mastoid structure may be affected by factors such as electrolyte corrosion and stress generated by electrode reactions, resulting in changes in mastoid shape and increased surface roughness. These changes may alter the flow characteristics of the electrolyte and the contact state between the electrode and the electrolyte, thereby affecting the performance stability of the electrolyzer and requiring more frequent maintenance and replacement, increasing operating costs and maintenance workload. Furthermore, after assembly, the mastoid plates squeeze the catalytic layer on the electrode, causing it to become damaged, detach, and fail. This not only reduces electrode performance, but also causes detached catalytic material to clog system piping, which can seriously cause safety accidents.

[0005] In view of this, this application is hereby filed. Summary of the Invention

[0006] The purpose of the present invention is to provide a bipolar plate, a preparation method and an application thereof, so as to overcome the problems in the prior art of high contact resistance between the bipolar plate and the battery and the disadvantage of uniform current distribution on the electrodes.

[0007] The present invention is achieved in that: In a first aspect, the present invention provides a bipolar plate comprising a mesh surface, a support body, a main electrode plate, a support body and a mesh surface stacked in sequence, wherein the support body is formed by a plurality of metal wires or metal meshes arranged in sequence along the main electrode plate, the projection of the metal wires or metal meshes along at least one direction is a waveform, and a flow channel structure is formed between the metal wires or metal meshes.

[0008] In an optional embodiment, the projections of the metal wire or metal mesh in the first direction are all wavy, and the projections of the metal wire or metal mesh in the second direction are all second shapes, and the second shape is selected from one of a circle, a straight line, an ellipse, an irregular shape, a zigzag shape, a comb shape, and a grid shape; The first direction and the second direction are perpendicular to each other and parallel to the mesh surface.

[0009] In an optional embodiment, the material of the support is selected from at least one of nickel and nickel-based alloys, titanium and titanium alloys, cobalt and cobalt-based alloys, copper and copper-based alloys, silver and silver alloys, stainless steel, carbon steel, monel alloy, and Hastelloy alloy; and / or, the diameter of the metal wire or the wire constituting the metal mesh is 0.05 mm to 2 mm; And / or, the thickness of the support body is 1 mm to 100 mm; And / or, the porosity of the support body is 20%-95%.

[0010] In an optional embodiment, the mesh size of the mesh surface is 5-100 mesh; and / or, the porosity of the mesh surface is 15%-80%; And / or, the thickness of the mesh surface is 0.05mm-5mm; And / or, a hydrogen and oxygen evolution catalytic material is provided on a side of the mesh surface away from the main electrode plate.

[0011] In an optional embodiment, the material of the main electrode plate is selected from at least one of carbon steel, stainless steel, nickel and nickel alloys, titanium and titanium alloys, cobalt and cobalt-based alloys, copper and copper-based alloys, silver and silver alloys, monel alloy, Hastelloy alloy, and stainless steel; And / or, a nickel layer is provided on the surface of the main electrode plate, and the nickel layer has a density greater than 99% and a thickness of 10-500 μm.

[0012] And / or, the thickness of the main pole plate may be 1 mm-15 mm.

[0013] In an optional embodiment, the main pole plate is provided with a support body covering area and a support body non-covering area, and the support body non-covering area is provided with a flow channel hole and a fixing groove for connecting to other main pole plates.

[0014] In a second aspect, the present invention provides a method for preparing a bipolar plate according to any one of the aforementioned embodiments, comprising: Connecting two supports to both sides of the main electrode plate to obtain a composite electrode plate; The two mesh surfaces are respectively connected to both sides of the composite plate to obtain the bipolar plate.

[0015] In an optional embodiment, the main electrode plate and the support body are connected by at least one of brazing, argon arc welding, diffusion welding, resistance welding, extrusion, rivets, and laser welding; And / or, the main electrode plate is nickel-plated before being connected to the support body.

[0016] In an optional embodiment, the mesh surface and the composite electrode plate are connected by at least one of brazing, diffusion welding, resistance welding, argon arc welding, vacuum welding, laser welding, and ultrasonic welding; and / or, before the mesh is connected to the composite electrode plate, a hydrogen evolution catalyst and an oxygen evolution catalyst are formed on the mesh surface by at least one of electroplating, hydrothermal method, chemical reaction method, plasma spraying method, ultrasonic spraying method, supersonic flame method, arc spraying method, cold spraying method, casting method, and screen printing method; In a third aspect, the present invention provides an electrolytic cell comprising two end plates and electrolytic cell units sequentially arranged between the two end plates, wherein each of the electrolytic cell units comprises the bipolar plates, diaphragms and sealing sheets described in any one of the aforementioned embodiments sequentially arranged.

[0017] The present invention has the following beneficial effects: The implementation of this application can solve the problems of poor consistency, high contact resistance, uneven gas-liquid flow, and irreversible damage to the electrode catalytic material in the mastoid plate. On the one hand, by using a support mesh to replace the mastoid structure, the contact area between the bipolar plate and the electrode is greatly increased, effectively reducing the contact resistance; on the other hand, the porous structure and regular flow channel structure composed of the flexible metal wire mesh can effectively promote the flow and mass transfer of gas and liquid, making the current distribution on the electrode more uniform, avoiding local overheating and breakdown, and also avoiding damage to the electrode catalytic material. In addition, the technical solution disclosed in this application is also simple and convenient to operate, which is conducive to improving the consistency and reliability of the electrolyzer, thereby ensuring the safe and stable operation of the electrolyzer and electrolysis system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a schematic diagram of the structure of the composite bipolar plate of this application; Figure 2 Schematic diagram of the first mesh surface and the support in Example 1 (A, plan view is the first surface; B, plan view is the second surface); Figure 3 Schematic diagram of the composite bipolar plate in Example 1 (A is a schematic diagram of the first side; B is a schematic diagram of the second side); Figure 4 Schematic diagram of the first mesh surface and the support in Example 2 (A, plan view is the first surface; B, plan view is the second surface); Figure 5 Schematic diagram of the integrated bipolar plate in Example 2 (A is a schematic diagram of the first side; B is a schematic diagram of the second side); Figure 6 Schematic diagram of the first mesh surface and the support in Example 3 (A, plan view is the first surface; B, plan view is the second surface); Figure 7 Schematic diagram of the integrated bipolar plate in Example 3 (A is a schematic diagram of the first side; B is a schematic diagram of the second side); Figure 8 Schematic diagram of the first mesh surface and the support in Example 4 (A, plan view is the first surface; B, plan view is the second surface); Figure 9 Schematic diagram of the integrated bipolar plate in Example 4 (A is a schematic diagram of the first side; B is a schematic diagram of the second side); Figure 10 Schematic diagram of the first mesh surface and the support in Example 5 (A, plan view is the first surface; B, plan view is the second surface); Figure 11 Schematic diagram of the integrated bipolar plate in Example 5 (A is a schematic diagram of the first side; B is a schematic diagram of the second side); Figure 12 Schematic diagram of an electrolytic cell assembled with a composite bipolar plate.

[0020] Illustration: 100 - bipolar plate; 110 - mesh surface; 120 - support body; 130 - main electrode plate; 131 - flow channel hole; 131a - liquid inlet hole; 131b - liquid outlet hole; 132 - fixing groove; 200 - end plate; 300 - diaphragm; 400 - sealing sheet. DETAILED DESCRIPTION

[0021] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0022] An embodiment of the present invention provides a bipolar plate 100, comprising a mesh surface 110, a support body 120, a main electrode plate 130, a support body 120 and a mesh surface 110 stacked in sequence, wherein the support body 120 is formed by a plurality of metal wires or metal meshes arranged in sequence along the main electrode plate 130, wherein the projection of the metal wires or metal meshes along at least one direction is a waveform, and a flow channel structure is formed between the metal wires or metal meshes.

[0023] In the present application, the mesh surface 110 has certain pores and a flat surface, and can be obtained by weaving or spinning one or two of metal wires and fibers, or by stretching, extruding, or deforming a metal sheet; the support body 120 is woven from metal wires or bent from a metal mesh, and has good flow-conducting, conductive, and supporting effects, and has a large number of porous structures interwoven with metal wires or meshes, and the porous structures are connected to form a flow channel structure, and the flow channel structure can be in a "Z" shape, a straight line, or other shapes that change periodically; the main pole plate 130 is a flat plate made of metal with a certain thickness and size. In an optional embodiment, the projections of the metal wires or metal meshes in the first direction are all wavy, and the projections of the metal wires or metal meshes in the second direction are all in a second shape, and the second shape is selected from one of a circle, a line, an ellipse, an irregular shape, a serrated shape, a comb shape, and a grid shape; The first direction and the second direction are perpendicular to each other and parallel to the mesh surface 110 .

[0024] The support body 120 in the present application is obtained by sequentially translating or arranging a metal wire or metal mesh along the first direction and the second direction. In the waveform projection or the projection of the second shape, the width of the flow channel between adjacent waveforms on the surface at equal distances from the mesh surface 110 is equal.

[0025] In an optional embodiment, the material of the support body 120 is selected from at least one of nickel and nickel-based alloys, titanium and titanium alloys, cobalt and cobalt-based alloys, copper and copper-based alloys, silver and silver alloys, stainless steel, carbon steel, monel alloy, and Hastelloy alloy; the support body 120 needs to have a certain electrical conductivity while taking into account mechanical strength and corrosion resistance.

[0026] and / or, the diameter of the metal wire or the wire constituting the metal mesh is 0.05 mm to 2 mm; And / or, the thickness of the support body 120 is 1 mm-100 mm, preferably 2 mm-15 mm; reducing the thickness of the support body 120 is beneficial to reducing costs and improving power density, but too low a thickness will increase deformability, thereby affecting sealing.

[0027] And / or, the porosity of the support body 120 is 20%-95%, preferably 40%-95%.

[0028] The diameter of the metal wire or the wire constituting the metal mesh and the porosity of the support 120 will affect the number, density and distribution of the flow channels. Reasonable adjustment of the diameter and porosity is conducive to balancing gas diffusion and liquid water discharge as well as uniform distribution of current.

[0029] In an optional embodiment, the mesh size of the mesh surface 110 is 5-100 mesh; And / or, the porosity of the mesh surface 110 is 15%-85%, preferably 30%-85%; the mesh surface 110 plays a supporting role on the one hand, and on the other hand, the reasonable setting of the mesh size and porosity is conducive to reducing the obstruction of current conduction.

[0030] And / or, the thickness of the mesh surface 110 is 0.05 mm-5 mm; reducing the thickness of the mesh surface 110 is beneficial to reducing costs and improving power density, but too low a thickness will increase deformation, thereby affecting sealing.

[0031] And / or, a hydrogen and oxygen evolution catalytic material is provided on a side of the mesh surface 110 away from the main electrode plate 130. The hydrogen and oxygen evolution catalytic material facilitates the generation of hydrogen and oxygen, and can also serve as an electrochemical protective layer to protect the mesh surface 110. The geometric shape of the mesh surface 110 can be any one of square, rectangular, and circular; When the geometric shape is a square or a rectangle, its dimensions include length, width and thickness; the length and width can be any value between 10 cm and 450 cm; the thickness can be any value between 0.05 mm and 5 mm; When the geometric shape is circular, its dimensions include diameter and thickness; the diameter can be any value between 10 cm and 450 cm; the thickness can be any value between 0.05 mm and 5 mm; Preferably, the shape is circular, the diameter is 60 cm-250 cm, and the pore size is 20 mesh-60 mesh; In an optional embodiment, the material of the main pole plate 130 is selected from at least one of carbon steel, stainless steel, nickel and nickel alloys, titanium and titanium alloys, cobalt and cobalt-based alloys, copper and copper-based alloys, silver and silver alloys, monel alloy, Hastelloy alloy, and stainless steel; the main pole plate 130 is selected from a material with good conductivity, good corrosion resistance, and high mechanical strength, which is beneficial to improving the performance of the electrolytic cell.

[0032] Alternatively, a nickel layer is provided on the surface of the main electrode plate 130, wherein the nickel layer has a density greater than 99% and a thickness of 10-500 μm. The presence of the nickel layer can improve the corrosion resistance of the main electrode plate 130, reduce contact resistance, and enhance surface wettability. In particular, when the main electrode plate 130 is made of carbon steel or ferritic stainless steel, the nickel layer is provided on its surface.

[0033] And / or, the thickness of the main pole plate 130 may be 1 mm to 15 mm. Reducing the thickness of the main pole plate 130 is beneficial to reducing costs and improving power density. However, too low a thickness may increase deformation, thereby affecting sealing.

[0034] The main pole plate 130 has a geometric shape and size similar to or consistent with the mesh surface 110; specifically, when the geometric shape is square or rectangular, the length and width of the main pole plate 130 can be any value between 15 cm and 500 cm, and the thickness of the main pole plate 130 can be any value between 1 mm and 15 mm; when the geometric shape is circular, the diameter of the main pole plate 130 can be any value between 15 cm and 500 cm, and the thickness of the main pole plate 130 can be any value between 1 mm and 15 mm.

[0035] In an optional embodiment, the main pole plate 130 is provided with a support body 120 covering area and a support body 120 non-covering area, and the support body 120 non-covering area is provided with a flow channel hole 131 and a fixing groove 132 for connecting with other main pole plates 130.

[0036] The flow channel holes 131 are one or more of circular, elliptical, flat, and arc-shaped. The hole for liquid inlet in the flow channel holes 131 is located at one end of the main electrode plate 130, and the hole for gas and liquid outlet is located at the other end. The gas and liquid outlet holes 131b are an even number and are symmetrically arranged along the diameter of the main electrode plate 130. The liquid inlet holes 131a are no more than three and are symmetrically arranged along the diameter of the main electrode plate 130. The cross-section of the fixing groove 132 is concave-convex, and the specific shape is one or more of rectangular, V-shaped, W-shaped, serrated, semicircular, elliptical, and arc-shaped; the fixing groove 132 is annular and is provided with one or more circles, and the two or more circles of fixing grooves 132 are concentrically arranged, and the number in the radial direction is one or more circles; the fixing groove 132 includes a concave surface and a convex surface, and the concave surface and the convex surface are adapted in size so that adjacent main pole plates 130 can be assembled with each other.

[0037] An embodiment of the present invention further provides a method for preparing the bipolar plate 100 according to any one of the aforementioned embodiments, comprising: Connect two supports 120 to both sides of the main electrode plate 130 to obtain a composite electrode plate; The two mesh surfaces 110 are respectively connected to the two sides of the composite plate to obtain the bipolar plate 100 .

[0038] Specifically, in some embodiments, the method for preparing the bipolar plate 100 includes: In the first step, metal wires, fibers, or plates are braided, woven, stretched, extruded, or deformed to form a flat mesh 110 or plate. The porosity of the mesh 110 is controlled by the gaps between the wires; or the porosity of the plate is controlled by the pore density during the stretching, extrusion, or deformation process. The resulting mesh 110 is then cut into multiple meshes of a certain size to obtain a mesh 110. In the second step, the metal wire is woven into a woven mesh with a corrugated structure to provide better support and larger pores, or the mesh surface 110 obtained in the first step is bent at regular intervals to form a folded mesh with a periodic undulating structure. The woven mesh or folded mesh obtained is cut into the required size specifications to obtain the support body 120; In the third step, the hydrogen evolution catalyst and the oxygen evolution catalyst are respectively disposed on the mesh surface 110 by one or more of electroplating, hydrothermal method, chemical reaction method, plasma spraying method, ultrasonic spraying method, supersonic flame method, arc spraying method, cold spraying method, casting method, and screen printing method. Specifically: When using electroplating, the bath temperature is 40-80°C, the pH value of the bath is 3-6, and the current density is 20-60 mA / cm 2 ; When the hydrothermal method is used, the reaction temperature is 90-150°C, the reaction time is 5-50 hours, the salt ion concentration is 0.1-2 mol / L, the pH value is 6-9, and the stirring speed is 100-500 rpm; When the chemical method is used, the reaction solution is mainly composed of nitrate, sulfate, sodium hypophosphite, citric acid, lactic acid, sodium acetate, thiourea, etc., with a concentration of 10-30g / L, a temperature of 80-100°C, a pH value of 4-7, and a stirring speed of 100-300rpm; When using the plasma spraying method, the spraying power is 20-50kW, the main gas flow rate is 30-60L / min, the auxiliary gas flow rate is 1-10L / min, the spray distance is 100-200mm, the spray gun moving speed is 500-1500mm / s, and the powder feeding amount is 50-200g / min; When ultrasonic spraying is used, the solution is mainly composed of solid particles, dispersants, etc., with a concentration of 0.1-2 mol / L, an ultrasonic head power of 1-10 W, a frequency of 20-80 kHz, a feed rate of 0.1-55 mL / min, a spraying distance of 100-500 mm, and a substrate temperature of 50-150°C; When using the supersonic flame spraying method, the oxygen flow rate is 50-120L / min, the oxygen pressure is 0.5-4MPa, the fuel flow rate is 100-1000mL / min, the spraying distance is 200-600mm, and the powder feeding speed is 30-200g / min; When arc spraying is used, the spraying voltage is 25-70V, the spraying current is 100-600A, the spraying distance is 100-300mm, the spray gun moving speed is 300-2000mm / s, the spraying gas pressure is 0.3-1MPa, and the wire feeding speed is 0.1-5m / min; When using the cold spray method, the chamber pressure is 3-9MPa, the gas temperature is 100-1200℃, the spraying distance is 10-100mm, and the powder feeding rate is 10-300g / min; When using the tape casting method, the slurry mainly consists of powder, binder, dispersant, etc. The casting speed is 1-50 mm / s, the scraper height is 0.1-1 mm, the drying temperature is 40-100 ° C, the drying time is 1-5 hours, the sintering temperature is 600-1200 ° C, the sintering time is 1-100 hours, and the sintering atmosphere is hydrogen or argon; When using the screen printing method, the slurry is mainly composed of powder, binder, thickener, and dispersant. The mesh number of the screen is 100-400 mesh, the screen tension is 10-60N / cm, the scraper angle is 40-70°, the printing speed is 50-300mm / s, the drying temperature is 80-150°C, the drying time is 10-300min, the sintering temperature is 600-1200°C, the sintering time is 1-100 hours, and the sintering atmosphere is hydrogen or argon.

[0039] In the fourth step, grooves and flow channel holes 131 are machined on the metal ring to obtain a metal pole frame; a metal plate made of the same material as the pole frame is welded to the metal pole frame by brazing, ultrasonic welding, argon arc welding, resistance welding, laser welding, etc. to obtain a main pole plate 130. If a non-nickel material is used, the main pole plate 130 needs to be nickel-plated. The outer diameter of the metal plate is consistent with the inner diameter of the pole frame. When welding, the metal plate is placed at the center of the pole frame. Four points are first welded along the outer edge of the metal plate at the "cross" position to prevent deformation of the metal plate or the pole frame. Then, the four areas divided by the four points are welded in a symmetrical manner in sequence to minimize deformation. When welding metal plates and pole frames, laser welding and ultrasonic welding are preferred to reduce deformation caused by heat input and contamination caused by solder; When the main electrode plate 130 obtained after welding is subjected to nickel plating, the nickel salts used are nickel sulfate, nickel nitrate, and nickel chloride, the nickel salt concentration is 150-500 g / L, and boric acid is added as a buffer in an amount of 20-50 g / L, the pH value is 3-5, the temperature is 40-70 ° C, and the current density is 10-100 mA / cm 2 , time is 50-300min, and the obtained nickel plating layer is 30-100μm.

[0040] In the fifth step, the obtained support body 120 is tightly connected to the main electrode plate 130 by brazing, argon arc welding, diffusion welding, resistance welding, vacuum welding, laser welding, ultrasonic welding, etc. to obtain a composite support electrode plate; among them, the use of ultrasonic welding to tightly connect the support body 120 and the main electrode plate 130 is more conducive to reducing the damage of heat input to the nickel plating on the main electrode plate 130.

[0041] In the sixth step, the sprayed mesh surface 110 and the composite support plate are tightly connected by laser welding, ultrasonic welding, resistance welding, etc. to obtain a composite bipolar plate 100; wherein, the sprayed mesh surface 110 and the composite support plate are tightly connected by resistance welding to reduce damage to the coating on the mesh surface 110.

[0042] In the seventh step, the obtained composite integrated bipolar plate 100, diaphragm 300 and gasket are stacked and assembled in sequence to obtain an alkaline electrolytic cell core. End plates 200 are set at both ends of the cell core and fastened with bolts to maintain a good sealing effect of the cell core, thereby obtaining an electrolytic cell that can be used for electrolysis of water to produce hydrogen and oxygen.

[0043] In an optional embodiment, the main pole plate 130 and the support body 120 are connected by at least one of brazing, argon arc welding, diffusion welding, resistance welding, extrusion, rivets, and laser welding; the main pole plate 130 and the support body 120 are tightly connected, which is conducive to reducing resistance.

[0044] And / or, the main electrode plate 130 is nickel-plated before being connected to the support body 120 .

[0045] In an optional embodiment, the mesh surface 110 and the composite electrode plate are connected by at least one of brazing, diffusion welding, resistance welding, argon arc welding, vacuum welding, laser welding, and ultrasonic welding; and / or, before the mesh surface 110 is connected to the composite electrode plate, a hydrogen evolution catalyst and an oxygen evolution catalyst are formed on the surface of the mesh surface 110 by at least one of electroplating, hydrothermal method, chemical reaction method, plasma spraying method, ultrasonic spraying method, supersonic flame method, arc spraying method, cold spraying method, casting method, and screen printing method; An embodiment of the present invention also provides an electrolytic cell, comprising two end plates 200 and electrolytic cell units sequentially arranged between the two end plates 200, each of the electrolytic cell units comprising the bipolar plate 100, diaphragm 300 and sealing sheet 400 described in any one of the aforementioned embodiments sequentially arranged.

[0046] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0047] Example 1 This embodiment provides a method for preparing an electrolytic cell, which specifically includes: In the first step, nickel wires are woven into a flat mesh surface 110. The porosity of the mesh surface 110 is controlled by the gaps between the nickel wires, resulting in a 40-mesh nickel wire mesh with a porosity of 48%. The resulting mesh surface 110 is then cut into 1.85 m x 1.85 m squares, resulting in a first mesh surface 110 and a second mesh surface 110 each having a size of 1.85 m x 1.85 m. In the second step, nickel wire with a wire diameter of 0.19 mm was woven into a woven mesh with a wave structure. The porosity was 48%. The obtained woven mesh showed a circular support structure in the plan view, with a circular diameter of 7 mm. The left view and the bottom view both showed a wave structure, with a trough width of 5 mm and a wave height of 7 mm. Figure 2 , cutting the obtained woven mesh into a specification of 1.8m×1.8m, obtaining a square first support body 120 and a second support body 120 with a size of 1.8m×1.8m, and the thickness of the support body 120 is 10mm; In the third step, Raney nickel is electroplated on the first mesh surface 110 and the second mesh surface 110 of 1.85 m×1.85 m obtained in the first step, respectively, at a plating temperature of 60° C., a plating pH of 4, and a current density of 30 mA / cm 2 The plating solution is mainly composed of nickel sulfate, sodium chloride, boric acid, etc., and the thickness of the obtained catalyst coating is 30μm.

[0048] The fourth step is to process the slots and flow channel holes 131 on the carbon steel ring by machining, wherein a flat liquid inlet hole 131a is set at the bottom, and two circular gas and liquid outlet holes 131b are set at the top. The cross section of the slot is rectangular, with one side being a rectangular depression and the other side being a rectangular protrusion. The rectangular slots on the two adjacent pole frames can be tightly fitted with each other. There are two rectangular slots in the radial direction. Figure 1 , in order to achieve a good sealing effect and obtain a carbon steel pole frame.

[0049] The carbon steel plate and the carbon steel pole frame are welded together by laser welding to obtain the main pole plate 130 .

[0050] During welding, a carbon steel plate with an outer diameter of 1.8m is placed at the center of the pole frame. Four points are welded along the outer edge of the steel plate. These four welding points are distributed in a "cross" shape to prevent deformation of the metal plate or the pole frame. Then, the four areas divided by the four points are welded in a symmetrical manner in turn to minimize deformation. The main electrode plate 130 obtained after welding is nickel-plated. The nickel salt used is nickel sulfate with a nickel salt concentration of 300 g / L. Boric acid is added as a buffer with an addition amount of 30 g / L. The pH value is 4, the temperature is 60°C, and the current density is 50 mA / cm 2 , the time is 150min, and the nickel coating obtained is about 40μm; Step 5: Cut the first support 120 and the second support 120 into circles and then tightly connect them to the main electrode plate 130 by ultrasonic welding to obtain a composite support electrode plate; In the sixth step, the first mesh surface 110 and the second mesh surface 110 after spraying are cut into circles and tightly connected to the composite support plate by resistance welding to obtain a composite bipolar plate 100. Figure 3 ; In the seventh step, the obtained composite integrated bipolar plate 100, diaphragm 300 and gasket are stacked and assembled in sequence to obtain an alkaline electrolytic cell core. End plates 200 are set at both ends of the cell core and fastened with bolts to maintain a good sealing effect of the cell core, thereby obtaining an electrolytic cell that can be used for electrolysis of water to produce hydrogen and oxygen.

[0051] Example 2 This embodiment provides a method for preparing an electrolytic cell, which specifically includes: In the first step, a nickel plate with a thickness of 0.5 mm is stretched to form a flat porous nickel expanded metal. The porosity of the expanded metal is controlled by the pore density of the stretching process, resulting in a 20-mesh expanded metal with a porosity of 72%. The resulting expanded metal is cut into circles with a diameter of 1.46 m, thereby obtaining a circular first mesh surface 110 and a second mesh surface 110 with a diameter of 1.46 m. In the second step, the monel alloy wire with a diameter of 1 mm is woven into a woven mesh with a wavy structure. The woven mesh with a thickness of 5 mm has a cross-circular structure in the plane view. The diameter of the circular structure is 5 mm. The left view and the bottom view show a wavy structure with a wave width of 5 mm and a wave height of 5 mm. Figure 4 , cutting the obtained woven mesh into a circle with a diameter of 1.4 m, obtaining a circular first support body 120 and a second support body 120 with a diameter of 1.4 m, and the porosity of the support body 120 is 80%; In the third step, nickel-cobalt double-layer hydroxide was placed on the first mesh surface 110 and the second mesh surface 110 obtained in the first step, respectively, by a hydrothermal method. The reaction temperature was 95° C., the reaction time was 9 hours, the salt ion concentration was 1 mol / L, the pH value was 8, and the stirring speed was 200 rpm. The fourth step is to process the grooves and flow channel holes 131 on the stainless steel ring by machining, add two flat liquid inlet holes 131a at one end of the pole frame, and process two circular liquid outlet holes 131b at the other end opposite thereto. On one side of the pole frame, three V-shaped inner grooves are processed from the outside to the inside along the outer circle of the pole frame. On the other side, three V-shaped outer convex grooves are processed on the other side of the pole frame. The two are of the same size and can be tightly assembled with each other to achieve a good sealing effect, thereby obtaining a metal pole frame. A stainless steel plate with an outer diameter of 1.46 mm is brazed together with a stainless steel pole frame to obtain a main pole plate 130. During welding, the stainless steel plate is placed at the center of the pole frame. Four points are welded along the outer circle of the stainless steel plate. The positions of the four points form a "cross" shape. The four areas divided by the four points are welded in a symmetrical manner in sequence to obtain the main pole plate 130. During nickel plating, nickel salts used were nickel nitrate and nickel chloride, with a nickel salt concentration of 450 g / L, and 20 / L boric acid was added as a buffer, the pH value was 3, the temperature was 60 ° C, and the current density was 70 mA / cm 2 , the time is 200min, and the nickel coating obtained is 50μm; Step 5: The first support 120 and the second support 120 are tightly connected to the main electrode plate 130 by ultrasonic welding to obtain a composite support electrode plate; In the sixth step, the sprayed first mesh surface 110, the second mesh surface 110 and the composite support plate are tightly connected by resistance welding to obtain a composite bipolar plate 100. Figure 5 ; In the seventh step, the obtained composite integrated bipolar plate 100, diaphragm 300 and gasket are stacked and assembled in sequence to obtain an alkaline electrolytic cell core. End plates 200 are set at both ends of the cell core and fastened with bolts to maintain a good sealing effect of the cell core, thereby obtaining an electrolytic cell that can be used for electrolysis of water to produce hydrogen and oxygen.

[0052] Example 3 This embodiment provides a method for preparing an electrolytic cell, which specifically includes: In the first step, nickel fibers with a wire diameter of 0.25 mm are woven into a flat mesh 110. The porosity of the mesh 110 is controlled by the spreading density of the nickel fibers, and the porosity is 20%. A 60-mesh mesh 110 with a thickness of 0.45 mm is obtained. The obtained mesh 110 is cut into circles with a diameter of 1 m, thereby obtaining a first circular mesh 110 and a second circular mesh 110 with a diameter of 1 m. In the second step, nickel-titanium alloy wire with a wire diameter of 0.3 mm is woven into a woven mesh with a wavy structure. The woven mesh with a thickness of 10 mm is in the shape of lines in the plane view with a line interval of 5 mm. The left view is in the shape of a wavy structure with a wave width of 5 mm and a wave height of 10 mm. The bottom view is in the shape of a straight line with a line interval of 5 mm. Figure 6 , cutting the obtained woven mesh into a circle with a diameter of 0.95 m, obtaining a circular first support body 120 and a second support body 120 with a diameter of 0.95 m, and the porosity of the support body 120 is 85%; In the third step, nickel-iron double-layer hydroxide is disposed on the first mesh surface 110 obtained in the first step by a chemical reaction method, and Raney nickel is disposed on the second mesh surface 110 obtained in the first step by plasma spraying; When the nickel-iron double-layer hydroxide catalyst is prepared by chemical method, the reaction solution mainly consists of nickel sulfate, iron sulfate, sodium hypophosphite, citric acid, lactic acid, sodium acetate, thiourea, etc., with a concentration of 25g / L, a temperature of 90°C, a pH value of 5, and a stirring speed of 100rpm; When plasma spraying was used to prepare Raney nickel catalyst, the spraying power was 35kW, the main gas flow rate was 40L / min, the auxiliary gas flow rate was 5L / min, the spray distance was 150mm, the spray gun moving speed was 800mm / s, and the powder feeding rate was 90g / min. In the fourth step, grooves and flow channel holes 131 are machined on the nickel-titanium alloy ring. An arc-shaped liquid inlet hole 131a is set at one end of the pole frame, and two elliptical liquid outlet holes 131b are set at the other end opposite to it. Three concave grooves with a semicircular cross-section are set inward along the outer circle on one side of the pole frame, and three corresponding convex semicircular grooves are set on the other side of the pole frame. The two can be tightly assembled with each other to obtain a metal pole frame. The main electrode plate 130 is obtained by laser welding a nickel-titanium alloy plate with a length of 1 m to a nickel-titanium alloy pole frame. During welding, the nickel-titanium alloy plate is placed in the center of the pole frame. Four points are welded along the outer edge of the alloy plate to form a "cross" distribution. Then, the four areas divided by the four points are welded in a symmetrical manner. When the main electrode plate 130 obtained after welding is not nickel-plated, Step 5: The first support body 120 and the second support body 120 are tightly connected to the main electrode plate 130 by ultrasonic welding or other methods to obtain a composite support electrode plate; In the sixth step, the sprayed first mesh surface 110, the second mesh surface 110 and the composite support plate are tightly connected by welding to obtain a composite integrated bipolar plate 100, as shown in FIG. Figure 7 ; In the seventh step, the obtained composite integrated bipolar plate 100, diaphragm 300 and gasket are stacked and assembled in sequence to obtain an alkaline electrolytic cell core. End plates 200 are set at both ends of the cell core and fastened with bolts to maintain a good sealing effect of the cell core, thereby obtaining an electrolytic cell that can be used for electrolysis of water to produce hydrogen and oxygen.

[0053] Example 4 This embodiment provides a method for preparing an electrolytic cell, which specifically includes: In the first step, nickel wires with a wire diameter of 0.19 mm are woven into a flat mesh surface 110. The porosity of the mesh surface 110 is controlled by the gaps between the wires, resulting in a 46-mesh nickel mesh surface 110 with a thickness of 0.4 mm and a porosity of 43%. The resulting nickel mesh is cut into circles with a diameter of 2.4 μm, resulting in a first circular mesh surface 110 and a second circular mesh surface 110 with a diameter of 2.4 μm. In the second step, the nickel mesh obtained in the first step is bent into a folded mesh having a plurality of rectangular flat straight channels with a cross-section of 7 mm × 7 mm and a thickness of 7 mm. The folded mesh is cut into a square with a diameter of 2.3 m to obtain a square first support 120 and a second support 120 with a diameter of 2.3 m, such as Figure 8 , the porosity of the support 120 is 43%; In the third step, Raney nickel and indium oxide are respectively disposed on the first mesh surface 110 and the second mesh surface 111 obtained in the first step by supersonic flame method and ultrasonic spraying method; When preparing indium oxide catalyst by ultrasonic spraying, the solution mainly consists of indium oxide particles and dispersant, with a concentration of 0.5 mol / L, an ultrasonic head power of 5 W, a frequency of 40 kHz, a feed rate of 3 mL / min, a spraying distance of 130 mm, and a substrate temperature of 80°C. When spraying Raney nickel catalyst by supersonic flame spraying, the oxygen flow rate is 70L / min, the oxygen pressure is 1MPa, the fuel flow rate is 130mL / min, the spraying distance is 300mm, and the powder feeding speed is 60g / min; In the fourth step, a groove and a flow channel hole 131 are machined on the nickel ring. Two flat liquid inlets are set at one end of the ring, and two flat liquid outlets are set at the other end of the ring to obtain a nickel pole frame. A serrated groove is machined along the outer edge of one side of the pole frame, and a serrated convex groove is machined at the corresponding position on the other side of the pole frame so that the two can be tightly assembled with each other. The nickel plate and the pole frame are welded together by laser welding to obtain the main pole plate 130, and the welding method is the same as that of Example 3; the main pole plate 130 obtained after welding is not subjected to nickel plating treatment; In the fifth step, the first support 120 and the second support 120 are tightly connected to the main electrode plate 130 by resistance welding to obtain a composite support electrode plate, such as Figure 9 ; Step 6: The sprayed first mesh surface 110, the second mesh surface 110 and the composite support plate are tightly connected by resistance welding to obtain a composite bipolar plate 100; In the seventh step, the obtained composite integrated bipolar plate 100, diaphragm 300 and gasket are stacked and assembled in sequence to obtain an alkaline electrolytic cell core. End plates 200 are set at both ends of the cell core and fastened with bolts to maintain a good sealing effect of the cell core, thereby obtaining an electrolytic cell that can be used for electrolysis of water to produce hydrogen and oxygen.

[0054] Example 5 This embodiment provides a method for preparing an electrolytic cell, which specifically includes: In the first step, nickel wires with a wire diameter of 0.25 mm are woven into a flat mesh surface 110. The porosity of the mesh surface 110 is controlled by the gaps between the wires, resulting in a 60-mesh nickel mesh surface 110 with a thickness of 0.5 mm and a porosity of 23%. The resulting nickel mesh is cut into circles with a diameter of 2.2 m, resulting in a first circular mesh surface 110 and a second circular mesh surface 110 with a diameter of 2.2 m. In the second step, nickel wire with a wire diameter of 0.25 mm is woven into a woven mesh with a wavy structure. The obtained woven mesh has a wavy structure in the plane view and the left view, with a wave width of 7 mm and a wave height of 7 mm. It has a circular structure in the bottom view, with a circular diameter of 7 mm, as shown in FIG. Figure 10 , cutting the obtained woven mesh into a circle with a diameter of 2.1 m, obtaining a circular first support body 120 and a second support body 120 with a diameter of 2.1 m, and the porosity of the support body 120 is 65%; In the third step, Raney nickel and nickel-molybdenum alloy are respectively disposed on the first mesh surface 110 and the second mesh surface 111 obtained in the first step by arc spraying and cold spraying; When arc spraying Raney nickel catalyst, the spraying voltage is 40V, the spraying current is 350A, the spraying distance is 160mm, the spray gun moving speed is 900mm / s, the spraying gas pressure is 0.6MPa, and the wire feeding speed is 0.5m / min; When cold spraying nickel-molybdenum alloy catalyst, the chamber pressure is 5 MPa, the gas temperature is 700°C, the spraying distance is 50 mm, and the powder feeding rate is 100 g / min; The fourth to seventh steps are the same as those in Example 4, and an electrolytic cell for producing hydrogen and oxygen by electrolyzing water is obtained, wherein the bipolar plate 100 used has the following structure: Figure 11 .

[0055] Example 6 This embodiment provides a method for preparing an electrolytic cell, which specifically includes: The first and second steps are the same as in Example 3; In the third step, nickel / nickel iron oxide and nickel cobalt / nickel hydroxide are respectively disposed on the first mesh surface 110 and the second mesh surface 111 obtained in the first step by tape casting and screen printing; When the nickel / nickel oxide catalyst is prepared by the tape casting method, the slurry mainly consists of nickel powder, nickel oxide powder, binder, dispersant, etc. The casting speed is 5 mm / s, the scraper height is 0.2 mm, the drying temperature is 60°C, the drying time is 3 hours, the sintering temperature is 900°C, the sintering time is 5 hours, and the sintering atmosphere is hydrogen; When the nickel-cobalt / nickel hydroxide catalyst is prepared by screen printing, the slurry is mainly composed of nickel-cobalt alloy powder, nickel hydroxide powder, binder, thickener, and dispersant. The screen mesh number is 200 mesh, the screen tension is 30 N / cm, the scraper angle is 57°, the printing speed is 200 mm / s, the drying temperature is 120°C, the drying time is 100 min, the sintering temperature is 900°C, the sintering time is 10 hours, and the sintering atmosphere is hydrogen.

[0056] The fourth to seventh steps are the same as those in Example 3, and an electrolytic cell for producing hydrogen and oxygen by electrolyzing water is obtained. Figure 12 .

[0057] Example 7 The only difference between this embodiment and embodiment 4 is that the cross-sectional dimensions of the flow channel of the support body 120 are different. The cross-sectional dimensions of the flow channel of the support body 120 are 10 mm×7 mm, where 10 mm is the flow channel width and 7 mm is the flow channel height.

[0058] Comparative Example 1 The only difference between this comparative example and Example 1 is that the support body is obtained by sequentially arranging the mastoid plates along the main electrode plates, and the porosity of the mesh surface 110 is kept unchanged.

[0059] The electrolytic cells prepared in the above embodiments were used to electrolyze water to produce hydrogen and oxygen. The resistance between the mesh surface 110 and the main electrode plate 130 was measured. 2 The cell voltage under electrical density and the percentage of damaged area of ​​the catalytic electrode coating are shown in Table 1.

[0060] Test methods include: Contact resistance: Use a multimeter to directly test the resistance and take the average value of 5 tests.

[0061] For the cell voltage, directly read the voltage of each cell on the electrolytic cell system interface, and use a multimeter to test the voltage of each cell in turn. If it is consistent with the voltage read by the system, take the system voltage value; otherwise, take the average value of 5 tests by the multimeter.

[0062] Loss ratio: the image method is used to count the damaged area of ​​the catalytic electrode surface coating after the test, and the ratio of the damaged area to the total area of ​​the catalytic electrode is calculated.

[0063] Table 1

[0064] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A bipolar plate, characterized in that: It includes a mesh surface, a support body, a main pole plate, a support body and a mesh surface which are stacked in sequence. The support body is obtained by sequentially arranging a plurality of metal wires or metal meshes along the main pole plate. The projection of the metal wires or metal meshes along at least one direction is a waveform, and a flow channel structure is formed between the metal wires or metal meshes.

2. The bipolar plate according to claim 1, characterized in that The projections of the metal wire or metal mesh in the first direction are all wavy, and the projections of the metal wire or metal mesh in the second direction are all in a second shape, and the second shape is selected from one of a circle, a straight line, an ellipse, an irregular shape, a zigzag shape, a comb shape, and a grid shape; The first direction and the second direction are perpendicular to each other and parallel to the mesh surface.

3. The bipolar plate according to claim 1, characterized in that The material of the support is selected from at least one of nickel and nickel-based alloys, titanium and titanium alloys, cobalt and cobalt-based alloys, copper and copper-based alloys, silver and silver alloys, stainless steel, carbon steel, monel alloy, and Hastelloy alloy; and / or, the diameter of the metal wire or the wire constituting the metal mesh is 0.05 mm to 2 mm; And / or, the thickness of the support body is 1 mm to 100 mm; And / or, the porosity of the support body is 20%-95%.

4. The bipolar plate according to claim 1, characterized in that The mesh size of the mesh surface is 5-100 mesh; and / or, the porosity of the mesh surface is 15%-85%; And / or, the thickness of the mesh surface is 0.05mm-5mm; And / or, a hydrogen and oxygen evolution catalytic material is provided on a side of the mesh surface away from the main electrode plate.

5. The bipolar plate according to claim 1, characterized in that The material of the main electrode plate is selected from at least one of carbon steel, stainless steel, nickel and nickel alloys, titanium and titanium alloys, cobalt and cobalt-based alloys, copper and copper-based alloys, silver and silver alloys, monel alloy, Hastelloy alloy, and stainless steel; And / or, a nickel layer is provided on the surface of the main electrode plate, wherein the nickel layer has a density greater than 99% and a thickness of 10-500 μm; And / or, the thickness of the main pole plate may be 1 mm-15 mm.

6. The bipolar plate according to claim 1, characterized in that The main pole plate is provided with a support body covering area and a support body non-covering area, and the support body non-covering area is provided with a flow channel hole and a fixing groove for connecting with other main pole plates.

7. A method for preparing a bipolar plate according to any one of claims 1 to 6, characterized in that: include: Connecting two supports to both sides of the main electrode plate to obtain a composite electrode plate; The two mesh surfaces are respectively connected to both sides of the composite plate to obtain the bipolar plate.

8. The method for preparing a bipolar plate according to claim 7, characterized in that: The main electrode plate and the support body are connected by at least one of brazing, argon arc welding, diffusion welding, resistance welding, extrusion, rivets, and laser welding; And / or, the main electrode plate is nickel-plated before being connected to the support body.

9. The method for preparing a bipolar plate according to claim 7, wherein: The mesh surface and the composite electrode plate are connected by at least one of brazing, diffusion welding, resistance welding, argon arc welding, vacuum welding, laser welding, and ultrasonic welding; And / or, before the mesh is connected to the composite electrode plate, a hydrogen evolution catalyst and an oxygen evolution catalyst are formed on the mesh surface by at least one of electroplating, hydrothermal method, chemical reaction method, plasma spraying method, ultrasonic spraying method, supersonic flame method, arc spraying method, cold spraying method, casting method, and screen printing method.

10. An electrolytic cell, characterized in that: The invention comprises two end plates and electrolytic cell units sequentially arranged between the two end plates, and each of the electrolytic cell units comprises the bipolar plate, diaphragm and sealing sheet according to any one of claims 1 to 6 sequentially arranged.

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