Electrolytic hydrogen production electrolytic bath

Abstract

The invention belongs to the technical field of water electrolysis hydrogen production, and particularly relates to an electrolytic hydrogen production electrolytic bath. Comprising a composite electrode assembly; the composite electrode assembly comprises an electrode frame, a bipolar plate, an electrode conductive frame, an oxygen evolution electrode and a hydrogen evolution electrode, the electrode frame is arranged on the outer side of the bipolar plate, the electrode frame and the bipolar plate are both made of plastic materials, the electrode conductive frame is arranged in the electrode frame, and the oxygen evolution electrode and the hydrogen evolution electrode are arranged on the two sides of the bipolar plate respectively and both connected with the electrode conductive frame. By adopting the plastic-based bipolar plate, a sealing effect can be achieved, a sealing gasket part of a traditional electrolytic cell is removed, and the cost of the electrolytic cell is greatly reduced; and the plastic-based bipolar plate, the electrode and the electrode conductive frame are integrated into a whole, so that the assembling and integrating process of the electrolytic cell is greatly simplified.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogen production by electrolysis of water, and particularly relates to an electrolytic cell for hydrogen production by electrolysis. Background Art

[0002] Hydrogen is not only an ideal clean energy carrier, but also an extremely important chemical raw material. The hydrogen obtained by electrolyzing water with renewable energy is called "green hydrogen" and is the future development direction of the energy and chemical industries. The electrolysis technology of hydrogen production is mainly divided into alkaline water electrolysis technology (AWE), proton exchange membrane water electrolysis technology (PEM) and solid oxide water electrolysis technology (SOE). Alkaline water electrolysis has a simple structure, mature technology and low cost. It is the most widely used water electrolysis technology in the field of large-scale hydrogen production.

[0003] like Figure 1-2 As shown, the alkaline water electrolysis hydrogen production device mainly includes an electrolyzer and an auxiliary frame with functions such as gas-liquid separation and purification. The electrolyzer is mainly composed of end pressure plates, bipolar plates 2, electrodes, diaphragms 5, sealing gaskets and bolts, and is the core component of the alkaline water electrolysis hydrogen production device. During operation, the inlet liquid is divided into two and enters the reaction chambers on both sides of the diaphragm 5 respectively. The electrode tank discharges liquid through two channels to the gas-liquid separator I15 and the gas-liquid separator II14, thereby producing oxygen and hydrogen. The electrolyte in the gas-liquid separator I15 and the gas-liquid separator II14 is collected and circulated to the electrolyzer again. On the one hand, it is estimated that in the manufacturing cost of the electrolyzer, bipolar plates account for 44%, sealing materials account for 8%, end pressure plates account for 5%, electrodes account for 28%, and diaphragms account for 8%. The bipolar plate is a key component that affects the manufacturing cost of the electrolyzer. In order to meet the requirements of high-temperature strong alkali corrosion, high-pressure alkaline gas-liquid sealing, porous electrode current collection, electrolyte and gas flow and other functions, the current electrolyzer bipolar plates are generally made of thin carbon steel plates that are precisely stamped into double-sided mastoid plates, and welded to thick carbon steel pole frames, and then nickel-plated as a whole. The thickness of the pole frame and the bipolar plate is different. The reason is that after the bipolar plate is stamped into a double-sided mastoid plate, the mastoid occupies a certain thickness space, which can accommodate the flow of electrolyte, but it leads to a long bipolar plate processing process, and the pole frame and the pole plate need to be processed separately and welded into a whole, which has high material / processing costs, directly leading to an increase in the cost of alkaline water electrolysis hydrogen production equipment, affecting the larger-scale application of alkaline water electrolysis hydrogen production technology. On the other hand, the carbon steel material generally used in bipolar plates is not highly conductive. The electrode and the top of the bipolar plate mastoid are electrically connected by pressing. The contact resistance is large due to pressure, corrosion, etc., which leads to a large voltage drop caused by the resistance of the electrolyzer, which directly leads to an increase in the DC power consumption of the alkaline water electrolysis hydrogen production device. The increase in electrolytic cell resistance also leads to an increase in heat generation power, which further leads to an increase in the heat dissipation demand of the hydrogen production device. The above two important issues have led to an increase in the manufacturing or use costs of alkaline water electrolysis hydrogen production devices, affecting the larger-scale application of alkaline water electrolysis hydrogen production technology. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide an electrolytic cell for producing hydrogen by electrolysis, so as to solve the problem of high manufacturing and use costs of existing alkaline water electrolysis hydrogen production electrolytic cells.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides an electrolytic hydrogen production electrolyzer, comprising a composite electrode assembly;

[0007] The composite electrode assembly includes a pole frame, a bipolar plate, an electrode conductive frame, an oxygen evolution electrode and a hydrogen evolution electrode, wherein the pole frame is arranged on the outside of the bipolar plate, and both the pole frame and the bipolar plate are made of plastic material, the electrode conductive frame is arranged inside the pole frame, the oxygen evolution electrode and the hydrogen evolution electrode are respectively arranged on both sides of the bipolar plate, and both are connected to the electrode conductive frame.

[0008] The pole frame, bipolar plate and electrode conductive frame are all annular, the bipolar plate is circular, the cross-section of the electrode conductive frame is a U-shaped groove structure including the outer edge of the bipolar plate, the inner edge of the electrode conductive frame is exposed on the inner surface of the pole frame and is located on both sides of the bipolar plate.

[0009] The electrode conductive frame is made of carbon steel, stainless steel, carbon steel nickel-plated or pure nickel plate by stamping and welding; the thickness of the electrode conductive frame is 1-3mm, and a plurality of through holes for connecting the electrode frame and the bipolar plate are arranged on the electrode conductive frame.

[0010] The pole frame is provided with a liquid inlet and a liquid outlet along the axial direction, and both the liquid inlet and the liquid outlet penetrate the electrode conductive frame; the inner surface of the pole frame is provided with a plurality of flow channels connected with the liquid inlet and the liquid outlet respectively along the radial direction.

[0011] The pole frame, electrode conductive frame and bipolar plate are an integrated structure, and both side edges of the pole frame are provided with annular sealing lines.

[0012] The bipolar plate comprises a reaction zone located in the center, and a plurality of nipples are arranged on both sides of the reaction zone; the oxygen evolution electrode and the hydrogen evolution electrode are connected to the electrode conductive frame by welding or by screws.

[0013] The bipolar plate has a thickness of 3-20 mm. A porous mesh is arranged on both sides of the bipolar plate. The porous mesh is welded to the electrode conductive frame. The oxygen evolution electrode and the hydrogen evolution electrode are respectively attached to the porous mesh on both sides of the bipolar plate.

[0014] The two composite electrode assemblies are stacked with a diaphragm disposed in between, and a hydrogen evolution reaction chamber and an oxygen evolution reaction chamber are formed on both sides of the diaphragm.

[0015] A plurality of the electrolytic hydrogen production cells are stacked in sequence, and two adjacent electrolytic hydrogen production cells share one bipolar plate; end pressure plates are provided at both ends of the plurality of electrolytic hydrogen production cells stacked in sequence, and the plurality of electrolytic hydrogen production cells are tightened and fixed by bolts.

[0016] The advantages and beneficial effects of the present invention are as follows: the present invention provides an electrolytic hydrogen production electrolyzer, which adopts a plastic-based bipolar plate, thereby greatly reducing the plate material and processing costs; the plastic-based bipolar plate itself can play a sealing role, eliminating the sealing gasket components of the traditional electrolyzer, thereby greatly reducing the cost of the electrolyzer; the plastic-based bipolar plate is integrated with the electrode and the electrode conductive frame, thereby greatly simplifying the electrolyzer assembly and integration process. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of a traditional electrolytic cell;

[0018] Figure 2 It is a schematic diagram of the decomposition of a traditional electrolytic cell;

[0019] Figure 3 This is a schematic structural diagram of an electrolytic cell for producing hydrogen by electrolysis according to the present invention;

[0020] Figure 4 An exploded view of an electrolytic cell for producing hydrogen by electrolysis according to the present invention;

[0021] Figure 5 It is a schematic diagram of the structure of the composite electrode assembly in the present invention.

[0022] In the figure: 1-polar frame, 2-bipolar plate, 3-seal, 4-oxygen evolution electrode, 5-diaphragm, 6-hydrogen evolution electrode, 7-liquid inlet, 8-papillary, 9-liquid outlet, 10-annular sealing line, 11-traditional bipolar plate welding point, 12-flow channel, 13-diaphragm groove, 14-gas-liquid separator II, 15-gas-liquid separator I, 16-electrode conductive frame, 21-reaction area, 22-sealing area. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] like Figure 3-4As shown, the present invention provides an electrolytic hydrogen production electrolyzer, including a composite electrode assembly; the composite electrode assembly includes a pole frame 1, a bipolar plate 2, an electrode conductive frame 16, an oxygen evolution electrode 4 and a hydrogen evolution electrode 6, wherein the pole frame 1 is arranged on the outside of the bipolar plate 2, the pole frame 1 and the bipolar plate 2 are both made of plastic, the electrode conductive frame 16 is arranged in the pole frame 1, the oxygen evolution electrode 4 and the hydrogen evolution electrode 6 are respectively arranged on both sides of the bipolar plate 2, and are both connected to the electrode conductive frame 16. The present invention adopts a plastic-based bipolar plate, which can play a sealing role, removes the sealing gasket component of the traditional electrolyzer, and greatly reduces the cost of the electrolyzer.

[0025] like Figure 4 As shown, in the embodiment of the present invention, the pole frame 1, the bipolar plate 2 and the electrode conductive frame 16 are all annular, the bipolar plate 2 is circular, the cross-section of the electrode conductive frame 16 is a U-shaped groove structure including the outer edge of the bipolar plate 2, and the inner annular edge of the electrode conductive frame 16 is exposed on the inner surface of the pole frame 1 and is located on both sides of the bipolar plate 2 so as to be connected to the oxygen evolution electrode 4 and the hydrogen evolution electrode 6 on both sides of the bipolar plate 2.

[0026] In an embodiment of the present invention, the electrode conductive frame 16 is made of carbon steel, stainless steel, carbon steel nickel-plated or pure nickel plate by stamping and welding; the thickness of the electrode conductive frame 16 is 1-3 mm. A plurality of through holes for connecting the pole frame 1 and the bipolar plate 2 are provided on the electrode conductive frame 16. Specifically, the pole frame 1, the electrode conductive frame 16 and the bipolar plate 2 are an integrated structure, and the plastic-based bipolar plate 2 is integrated with the electrode and the electrode conductive frame 16, which greatly simplifies the assembly and integration process of the electrolytic cell.

[0027] like Figure 5 As shown, in the embodiment of the present invention, a liquid inlet 7 and a liquid outlet 9 are axially arranged on the pole frame 1, and a plurality of flow channels 12 are radially arranged on the inner surface of the pole frame 1, which are respectively connected with the liquid inlet 7 and the liquid outlet 9. The liquid enters from the liquid inlet 7, and then enters the reaction chamber through the flow channel 12 connected with the liquid inlet 7; or, the liquid in the reaction chamber flows out from the liquid outlet 9 through the flow channel 12 connected with the liquid outlet 9.

[0028] Furthermore, an annular sealing line 10 is provided on both side surfaces of the pole frame 1 so as to be sealed and connected with the adjacent pole frame 1 .

[0029] In one embodiment of the present invention, the bipolar plate 2 includes a reaction zone 21 in the center, and a plurality of nipples 8 are provided on both sides of the reaction zone 21. Specifically, the oxygen evolution electrode 4 and the hydrogen evolution electrode 6 are connected to the electrode conductive frame 16 by welding or screws.

[0030] In another embodiment of the present invention, the thickness of the bipolar plate 2 is 3-20 mm, and a porous mesh is arranged on both sides of the bipolar plate 2, the porous mesh is welded to the electrode conductive frame 16, and the oxygen evolution electrode 4 and the hydrogen evolution electrode 6 are respectively attached to the porous mesh on both sides of the bipolar plate 2, thereby realizing the connection between the oxygen evolution electrode 4 and the hydrogen evolution electrode 6 and the electrode conductive frame 16.

[0031] Specifically, the pole frame 1 and the bipolar plate 2 are made of plastic or fiber-reinforced plastic, wherein the plastic includes polyethylene, polypropylene, polyvinyl chloride, ABS, PEEK, PTFE, epoxy resin, etc., and the fiber material includes glass fiber, carbon fiber, boron fiber, etc. The pole frame 1 and the bipolar plate 2 made of plastic material can be integrally formed by injection molding, or can be manufactured by compression molding, milling, 3D printing, etc. The thickness of the bipolar plate 2 is 3-20 mm, preferably 5-12 mm.

[0032] like Figure 3-4 As shown, in the embodiment of the present invention, two composite electrode assemblies are stacked and a diaphragm 5 is arranged in the middle, the diaphragm 5 is accommodated in a diaphragm groove 13 provided on the corresponding surfaces of the two electrode frames 1, and a hydrogen evolution reaction chamber and an oxygen evolution reaction chamber are formed on both sides of the diaphragm 5; the oxygen evolution electrode 4 and the hydrogen evolution electrode 6 are respectively accommodated in the oxygen evolution reaction chamber and the hydrogen evolution reaction chamber on both sides of the diaphragm 5.

[0033] On the basis of the above embodiment, a plurality of electrolytic hydrogen production cells are stacked in sequence, and a composite electrode assembly is shared between two adjacent electrolytic hydrogen production cells; end pressure plates are arranged at both ends of the plurality of electrolytic hydrogen production cells stacked in sequence, and the two end plates are connected by bolts, and the bolts penetrate through each electrolytic hydrogen production cell, so as to tighten and fix the plurality of electrolytic hydrogen production cells.

[0034] Embodiment 1

[0035] The electrode conductive frame 16 is obtained by laser cutting, stamping, welding and nickel electroplating of a 2 mm carbon steel plate. The electrode conductive frame 16 is fixed in an injection mold, and a bipolar plate frame conductive seal integrated part is obtained by injection molding of soluble polytetrafluoroethylene. The hydrogen evolution electrode 6 uses a nickel mesh sprayed with Raney nickel, and the oxygen evolution electrode 4 uses a nickel mesh. The hydrogen evolution electrode 6 and the oxygen evolution electrode 4 are respectively welded to the electrode conductive frame 16 on both sides of the integrated part to obtain a composite electrode assembly. The diaphragm 5 uses PPS cloth. 40 mm thick end pressure plates are used on both sides of the electrolyzer, and they are stacked in the order of end pressure plate-composite electrode assembly-diaphragm-composite electrode assembly-diaphragm-composite electrode assembly-end pressure plate, and a new type of electrolyzer without sealing pad is obtained by tightening the screw. The number of small chambers of the electrolyzer is 10. The electrolytic cell was installed in the water electrolysis test device. The electrolyte used was 30% KOH solution. The operating temperature was 90° C., the operating pressure was 0.6 MPa, the electrolysis current was 125 A, and the electrolytic cell processing time and electrolytic cell voltage were recorded.

[0036] The processing time of the electrode conductive frame 16 is: laser cutting 1min, stamping 0.5min, welding 5min, electroplating 30min, and the total time is 36.5min. Electrolytic cell voltage: 18.10V; electrolytic cell DC power consumption: 4.32kWh / Nm 3 H2

[0037] Embodiment 2

[0038] The electrode conductive frame 16 is obtained by laser cutting, stamping and welding of a 2 mm pure nickel plate, and the electrode conductive frame 16 is fixed in an injection mold. The bipolar plate, pole frame and conductive seal are obtained by PEEK injection molding. The hydrogen evolution electrode 6 is a nickel mesh sprayed with Raney nickel, and the oxygen evolution electrode 4 is a nickel mesh. The hydrogen evolution electrode 6 and the oxygen evolution electrode 4 are respectively fixed to the electrode conductive frame 16 on both sides of the integral part by screws to obtain a composite electrode assembly. The diaphragm 5 is made of PPS cloth, and 40 mm thick end pressure plates are used on both sides of the electrolyzer. The end pressure plate-composite electrode assembly-seal-diaphragm-composite electrode assembly-seal-diaphragm-composite electrode assembly-end pressure plate are stacked in the order of end pressure plate-composite electrode assembly-seal-diaphragm-composite electrode assembly-end pressure plate, and the new electrolyzer is tightened by screw rods. The number of small chambers of the electrolyzer is 10. The electrolyzer is installed in the electrolysis water test device, the electrolyte is 30% KOH solution, the operating temperature is 90 ° C, the operating pressure is 0.6 MPa, the electrolysis current is 125A, and the electrolyzer processing time and the electrolyzer voltage are recorded.

[0039] Processing time of electrode conductive frame 16: laser cutting 1min, stamping 0.5min, welding 5min, total time 6.5min. Electrolytic cell voltage: 18.20V; electrolytic cell DC power consumption: 4.35kWh / Nm 3 H2.

[0040] Comparative Example

[0041] The bipolar plate 2 is obtained by laser cutting and stamping of a 3 mm carbon steel plate, and the pole frame 1 is obtained by laser cutting and CNC processing of a 5 mm carbon steel plate. The bipolar plate 2 and the pole frame 1 are welded and nickel-plated to obtain a bipolar plate and pole frame integrated part, with a reaction area of ​​500 cm 2 , the seal 3 is made of 3mm glass fiber reinforced PTFE plate by CNC processing, the hydrogen evolution electrode uses a nickel mesh sprayed with Raney nickel, the oxygen evolution electrode uses a nickel mesh, the diaphragm 5 uses PPS cloth, and the two sides of the electrolytic cell use 40mm thick end pressure plates. Figure 1 The conventional electrolytic cell is stacked in the order shown, and the number of the electrolytic cell chambers is 10. The electrolytic cell is installed in the electrolytic water testing device, the electrolyte is 30% KOH solution, the operating temperature is 90°C, the operating pressure is 0.6MPa, the electrolysis current is 125A, and the electrolytic cell processing time and the electrolytic cell voltage are recorded.

[0042] Processing time of bipolar plate and pole frame: bipolar plate laser cutting 1min, bipolar plate stamping 0.5min, pole frame laser cutting 2min, pole frame CNC processing 2h, welding 30min, electroplating 30min, total time 183.5min. Processing time of seal: CNC processing 3min; electrolytic cell voltage: 18.18V; electrolytic cell DC power consumption: 4.35kWh / Nm 3 H2.

[0043] It can be seen that the processing time of the traditional electrolytic cell bipolar plate frame is long and the processing cost is high. The processing time of the new electrolytic cell bipolar plate frame conductive sealing integrated part is greatly reduced, which can greatly reduce the processing cost of the electrolytic cell.

[0044] The above description is only an embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, expansion, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. An electrolytic cell for producing hydrogen by electrolysis, characterized in that: including a composite electrode assembly; The composite electrode assembly comprises a pole frame (1), a bipolar plate (2), an electrode conductive frame (16), an oxygen evolution electrode (4) and a hydrogen evolution electrode (6), wherein the pole frame (1) is arranged on the outside of the bipolar plate (2), and the pole frame (1) and the bipolar plate (2) are both made of plastic material, the electrode conductive frame (16) is arranged inside the pole frame (1), and the oxygen evolution electrode (4) and the hydrogen evolution electrode (6) are respectively arranged on both sides of the bipolar plate (2) and are both connected to the electrode conductive frame (16).

2. The electrolytic hydrogen production cell according to claim 1, characterized in that: The pole frame (1) and the electrode conductive frame (16) are both annular, the bipolar plate (2) is circular, the cross section of the electrode conductive frame (16) is a U-shaped groove structure including the outer edge of the bipolar plate (2), the inner annular edge of the electrode conductive frame (16) is exposed on the inner surface of the pole frame (1) and is located on both sides of the bipolar plate (2).

3. The electrolytic cell for producing hydrogen by electrolysis according to claim 2, characterized in that: The electrode conductive frame (16) is made of carbon steel, stainless steel, carbon steel nickel-plated or pure nickel plate by stamping and welding; the thickness of the electrode conductive frame (16) is 1-3 mm, and a plurality of through holes for connecting the pole frame (1) and the bipolar plate (2) are arranged on the electrode conductive frame (16).

4. The electrolytic cell for producing hydrogen by electrolysis according to claim 1, characterized in that: The pole frame (1) is provided with a liquid inlet (7) and a liquid outlet (9) along the axial direction, and the liquid inlet (7) and the liquid outlet (9) both penetrate the electrode conductive frame (16); and the inner surface of the pole frame (1) is provided with a plurality of flow channels (12) along the radial direction, which are respectively connected with the liquid inlet (7) and the liquid outlet (9).

5. The electrolytic cell for producing hydrogen by electrolysis according to claim 1, characterized in that: The pole frame (1), the electrode conductive frame (16) and the bipolar plate (2) are an integrated structure, and both side edges of the pole frame (1) are provided with an annular sealing line (10).

6. The electrolytic cell for producing hydrogen by electrolysis according to claim 1, characterized in that: The bipolar plate (2) comprises a reaction zone (21) located in the center, and a plurality of nipples (8) are provided on both sides of the reaction zone (21).

7. The electrolytic cell for producing hydrogen by electrolysis according to claim 6, characterized in that: The oxygen evolution electrode (4) and the hydrogen evolution electrode (6) are connected to the electrode conductive frame (16) by welding or by screws.

8. The electrolytic cell for producing hydrogen by electrolysis according to claim 1, characterized in that: The bipolar plate (2) has a thickness of 3-20 mm, and porous meshes are arranged on both sides of the bipolar plate (2), the porous meshes are welded to the electrode conductive frame (16), and the oxygen evolution electrode (4) and the hydrogen evolution electrode (6) are respectively bonded to the porous meshes on both sides of the bipolar plate (2).

9. The electrolytic hydrogen production cell according to any one of claims 1 to 8, characterized in that: The two composite electrode assemblies are stacked with a diaphragm (5) disposed in between, and a hydrogen evolution reaction chamber and an oxygen evolution reaction chamber are formed on both sides of the diaphragm (5).

10. The electrolytic cell for producing hydrogen by electrolysis according to claim 9, characterized in that: A plurality of the electrolytic hydrogen production cells are stacked in sequence, and two adjacent electrolytic hydrogen production cells share one bipolar plate (2); end pressure plates are provided at both ends of the plurality of electrolytic hydrogen production cells stacked in sequence, and the plurality of electrolytic hydrogen production cells are tightened and fixed by bolts.

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