Electrolytic bath

Abstract

The invention belongs to the technical field of water electrolysis hydrogen production, and particularly relates to an electrolytic bath. Comprising a sealing piece, an electrode I, a diaphragm, an electrode II and bipolar plates, the two bipolar plates are connected in a sealed mode through the sealing piece, the diaphragm is arranged between the two bipolar plates, two reaction chambers are formed in the two sides of the diaphragm respectively, the electrode I and the electrode II are arranged in the two reaction chambers respectively, and a liquid inlet and a liquid outlet are formed in each bipolar plate; a liquid inlet channel and a liquid outlet channel which are used for communicating the reaction chamber with the liquid inlet and the liquid outlet are formed in the sealing piece. The bipolar plate and the pole frame are combined into one machined part, so that the welding procedure of the pole frame and the polar plate is omitted; and meanwhile, a thick pole frame is not used, so that the material cost and the processing cost of the pole frame are greatly reduced.

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. 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. 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 bipolar plate 2 of the electrolyzer is generally made of thin carbon steel plate, which is precisely stamped into a double-sided mastoid plate, and welded to the pole frame 1 made of thick carbon steel, and then the whole is nickel-plated. The thickness of the pole frame 1 is different from that of the bipolar plate 2. The reason is that after the bipolar plate 2 is stamped into a double-sided mastoid plate, the mastoid occupies a certain thickness space, which can accommodate the flow of the electrolyte, but it leads to a long bipolar plate processing process, and the pole frame 1 and the pole plate 2 need to be processed separately and then welded into a whole. The material / processing cost is high, which directly leads 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. Summary of the invention

[0004] In view of the above problems, the object of the present invention is to provide an electrolytic cell 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 cell, comprising a sealing member, an electrode I, a diaphragm, an electrode II and a bipolar plate, wherein two bipolar plates are sealed and connected by a sealing member, the diaphragm is arranged between the two bipolar plates and fixed on the sealing member, two reaction chambers are formed on both sides of the diaphragm, the electrode I and the electrode II are arranged in the two reaction chambers, respectively, a liquid inlet and a liquid outlet are arranged in the bipolar plate; the sealing member is provided with a liquid inlet channel for connecting the reaction chamber with the liquid inlet and a liquid outlet channel for connecting the reaction chamber with the liquid outlet.

[0007] The liquid inlet channel and the liquid outlet channel on the seal have the same structure, both including a transverse channel and a flow channel. The transverse channel is axially arranged on the seal, and the flow channel is radially arranged on the side of the seal. The liquid entering from the liquid inlet passes through the transverse channel and the flow channel of the liquid inlet channel in sequence and enters the reaction chamber, or the liquid in the reaction chamber passes through the flow channel and the transverse channel of the liquid outlet channel and converges into the liquid outlet of the bipolar plate.

[0008] The sealing member comprises two stacked sealing rings, and corresponding sides of the two sealing rings are provided with diaphragm grooves, and the diaphragm is accommodated in the diaphragm groove between the two sealing rings.

[0009] The sealing element is an annular structure made of plastic or fiber reinforced plastic; the thickness of the sealing ring is 1-20 mm, the depth of the flow channel is 1-10 mm, and the depth of the diaphragm groove is 0.1-1 mm.

[0010] The bipolar plate includes a reaction zone located in the central area and a sealing zone located in the edge part, and the sealing zone is provided with the liquid inlet and the liquid outlet.

[0011] The bipolar plate is a double-sided mastoid structure having a plurality of mastoids on both sides;

[0012] Alternatively, the bipolar plate is a plate mesh structure in which porous meshes are welded on both sides of a flat plate.

[0013] The bipolar plate is made of carbon steel, stainless steel, carbon steel plated with nickel, pure nickel or a graphite composite material, and the thickness of the bipolar plate is 1-10 mm.

[0014] The porous meshes on both sides of the bipolar plate are obtained by stretching carbon steel, stainless steel, carbon steel plated with nickel or pure nickel plate, and the thickness of the porous mesh is 1-5 mm.

[0015] The diaphragm is made of PPS cloth or a composite diaphragm.

[0016] The multiple electrolytic cells are stacked in sequence, and two adjacent electrolytic cells share one bipolar plate. End pressure plates are arranged at both ends of the multiple electrolytic cells, and the two end pressure plates are tightened and fixed by screws penetrating the multiple electrolytic cells.

[0017] The advantages and beneficial effects of the present invention are as follows: the present invention provides an electrolytic cell in which the bipolar plate and the pole frame are combined into one processed part, thereby eliminating the welding process of the pole frame and the pole plate; at the same time, because the present invention does not use a thick pole frame, the material cost and processing cost of the pole frame are greatly reduced.

[0018] The flow channel between the liquid inlet and outlet holes and the reaction zone of the traditional electrolytic cell is arranged on the pole frame, while the present invention moves it to the sealing member, further reducing the processing time of the pole frame and the pole plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of a traditional electrolytic cell;

[0020] Figure 2 It is a schematic diagram of the decomposition of a traditional electrolytic cell;

[0021] Figure 3 It is a structural schematic diagram of an electrolytic cell of the present invention;

[0022] Figure 4 It is an exploded schematic diagram of an electrolytic cell of the present invention;

[0023] Figure 5 Schematic diagram of the structure of the bipolar plate in the present invention;

[0024] Figure 6 It is a schematic diagram of the structure of the sealing member in the present invention.

[0025] In the figure: 1-polar frame, 2-bipolar plate, 3-seal, 4-electrode I, 5-diaphragm, 6-electrode II, 7-liquid inlet, 8-nipple, 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, 21-reaction area, 22-sealing area. DETAILED DESCRIPTION

[0026] 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.

[0027] like Figure 3-4As shown, the present invention provides an electrolytic cell, including a seal 3, an electrode I4, a diaphragm 5, an electrode II6 and a bipolar plate 2, wherein two bipolar plates 2 are sealed and connected by a seal 3, a diaphragm 5 is arranged between the two bipolar plates 2, two reaction chambers are formed on both sides of the diaphragm 5, electrodes I4 and II6 are arranged in the two reaction chambers, respectively, and a liquid inlet 7 and a liquid outlet 9 are arranged on the bipolar plate 2; a liquid inlet channel for connecting the reaction chamber with the liquid inlet 7 and a liquid outlet channel for connecting the reaction chamber with the liquid outlet 9 are arranged on the seal 3. The present invention combines the bipolar plate and the pole frame into one processed part, eliminating the welding process of the pole frame and the pole plate, and at the same time, a liquid inlet channel and a liquid outlet channel are arranged on the seal, further reducing the processing time of the pole frame and the pole plate.

[0028] like Figure 5 As shown, in an embodiment of the present invention, the bipolar plate 2 includes a reaction zone 21 located in the central area and a sealing zone 22 located in the edge portion, and the sealing zone 22 is provided with a liquid inlet 7 and a liquid outlet 9. In this embodiment, the bipolar plate 2 is a double-sided nipple structure having a plurality of nipples 8 on both sides. In an embodiment of the present invention, the bipolar plate 2 is made of carbon steel, stainless steel, carbon steel plated with nickel, pure nickel or a graphite composite material, and the thickness of the bipolar plate 2 is 1-10 mm, preferably in the range of 2-4 mm.

[0029] Alternatively, the bipolar plate 2 may also be a plate mesh structure with porous mesh welded on both sides of a flat plate. The porous mesh on both sides of the bipolar plate 2 is made of carbon steel, stainless steel, carbon steel nickel-plated or pure nickel plate by stretching, and the thickness of the porous mesh is 1-5 mm, preferably 1-3 mm.

[0030] Furthermore, the sealing area 22 of the bipolar plate 2 is provided with an annular sealing line, which is obtained by stamping or machining. In this embodiment, the bipolar plate 2 is an integrated structure of the bipolar plate and the pole frame formed by integral stamping, stamping + machining, machining + welding of a punching mesh, etc.

[0031] like Figure 6 As shown, in the embodiment of the present invention, the liquid inlet channel and the liquid outlet channel on the seal 3 have the same structure, both including a transverse channel and a flow channel 12, the transverse channel is axially arranged on the seal 3, the flow channel 12 is radially arranged on the side of the seal 3 and is connected with the transverse channel, the liquid entering from the liquid inlet 7 passes through the transverse channel and the flow channel 12 of the liquid inlet channel in turn into the reaction chamber, or the liquid in the reaction chamber passes through the flow channel 12 and the transverse channel of the liquid outlet channel and flows into the liquid outlet 9 of the bipolar plate 2.

[0032] In the embodiment of the present invention, the seal 3 includes two stacked seal rings, and the corresponding sides of the two seal rings are provided with a diaphragm groove 13, and the diaphragm 5 is accommodated in the diaphragm groove 13 between the two seal rings. Specifically, the seal 3 adopts an annular structure 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 thickness of the seal ring is 1-20mm, the depth of the flow channel 12 is 1-10mm, and the depth of the diaphragm groove 13 is 0.1-1mm.

[0033] In the embodiment of the present invention, the diaphragm 5 is made of PPS cloth or a composite diaphragm.

[0034] On the basis of the above embodiment, further, multiple electrolytic cells are stacked in sequence, and two adjacent electrolytic cells share a bipolar plate 2, and end pressure plates are set at both ends of the multiple electrolytic cells, and the two end pressure plates are tightened and fixed by screws that penetrate the multiple electrolytic cells.

[0035] Embodiment 1

[0036] The bipolar plate and frame are made of 3mm carbon steel plate through laser cutting, stamping and nickel electroplating, with a reaction area of ​​500cm 2 The seal 3 is made of 4mm glass fiber reinforced PTFE plate by CNC processing, the hydrogen evolution electrode (electrode II 6) uses a nickel mesh sprayed with Raney nickel, the oxygen evolution electrode (electrode I 4) uses a nickel mesh, the diaphragm 5 uses PPS cloth, and the two sides use 40mm thick end pressure plates. Figure 3 The electrolyzer was stacked in the order shown in the figure, and the new type of mastoid electrolyzer was obtained by tightening the screw, and the number of electrolyzer chambers was 10. The electrolyzer was installed in the electrolysis water test device, the electrolyte was 30% KOH solution, the operating temperature was 90°C, the operating pressure was 0.6MPa, the electrolysis current was 125A, and the electrolyzer processing time and electrolyzer voltage were recorded.

[0037] In this embodiment, the processing time of the bipolar plate frame is: laser cutting 1min, stamping 0.5min, electroplating 30min, and the total time is 31.5min. The processing time of the seal is: CNC processing 5min; the voltage of the electrolytic cell is 18.13V; the DC power consumption of the electrolytic cell is 4.33kWh / Nm 3 H2

[0038] Embodiment 2

[0039] A 2mm thick stretched nickel mesh was used to obtain a circular porous mesh through laser cutting. A 3mm thick carbon steel plate was laser cut, stamped, double-sided welded with the stretched nickel mesh, and electroplated with nickel to obtain a bipolar plate frame integrated component with a reaction area of ​​500cm 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 uses PPS cloth, and the two sides use 40mm thick end pressure plates. Figure 3 The electrolyzer was stacked in the order shown in the figure, and the new electrolyzer of plate mesh type was obtained by tightening the screw, and the number of electrolyzer chambers was 10. The electrolyzer was installed in the electrolysis water test device, the electrolyte was 30% KOH solution, the operating temperature was 90°C, the operating pressure was 0.6MPa, the electrolysis current was 125A, and the electrolyzer processing time and electrolyzer voltage were recorded.

[0040] In this embodiment, the processing time of the bipolar plate frame is: laser cutting of the stretched nickel mesh for 1 minute, laser cutting of the bipolar plate for 1 minute, stamping for 0.5 minutes, welding of the stretched nickel mesh for 2 minutes, electroplating for 30 minutes, and the total time is 34.5 minutes. Processing time of the seal: CNC processing for 5 minutes; electrolytic cell voltage: 17.95V; DC power consumption of the electrolytic cell: 4.29kWh / Nm 3 H2

[0041] Comparative Example

[0042] 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 10 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 uses PPS cloth, and the two sides use 40mm thick end pressure plates. Figure 1 The conventional electrolytic cell is stacked in the order shown and tightened by a screw rod, and the number of the electrolytic cell chambers is 10. The electrolytic cell is installed in a water electrolysis test 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.

[0043] Among them, the processing time of the bipolar plate and pole frame is: 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. Seal processing time: CNC processing 3min; electrolytic cell voltage: 18.18V; electrolytic cell DC power consumption: 4.35kWh / Nm 3 H2

[0044] It can be seen that the processing time of the conventional bipolar plate frame of the electrolytic cell is long and the processing cost is high; however, the processing time of the bipolar plate frame integrated part of the electrolytic cell of the present invention is greatly reduced, which can greatly reduce the processing cost of the electrolytic cell.

[0045] The present invention provides an electrolytic cell, in which the bipolar plate and the pole frame are combined into one processed part, eliminating the welding process of the pole frame and the pole plate; at the same time, because the present invention does not use a thick pole frame, the material cost and processing cost of the pole frame are greatly reduced. The flow channel between the inlet and outlet holes and the reaction zone of the traditional electrolytic cell is set on the pole frame, and the present invention moves it to the seal, further reducing the processing time of the pole frame and the pole plate.

[0046] 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, characterized in that: The invention comprises a sealing member (3), an electrode I (4), a diaphragm (5), an electrode II (6) and a bipolar plate (2), wherein the two bipolar plates (2) are sealed and connected via the sealing member (3), the diaphragm (5) is arranged between the two bipolar plates (2) and fixed on the sealing member (3), two reaction chambers are formed on both sides of the diaphragm (5), the electrode I (4) and the electrode II (6) are arranged in the two reaction chambers respectively, and a liquid inlet (7) and a liquid outlet (9) are arranged on the bipolar plate (2); and the sealing member (3) is provided with a liquid inlet channel for connecting the reaction chamber with the liquid inlet (7) and a liquid outlet channel for connecting the reaction chamber with the liquid outlet (9).

2. The electrolytic cell according to claim 1, characterized in that The liquid inlet channel and the liquid outlet channel on the sealing member (3) have the same structure, and both include a transverse channel and a flow channel (12). The transverse channel is axially arranged on the sealing member (3), and the flow channel (12) is radially arranged on the side of the sealing member (3). Liquid entering from the liquid inlet (7) sequentially passes through the transverse channel and the flow channel (12) of the liquid inlet channel into the reaction chamber, or liquid in the reaction chamber passes through the flow channel (12) and the transverse channel of the liquid outlet channel and flows into the liquid outlet (9) of the bipolar plate (2).

3. The electrolytic cell according to claim 2, characterized in that The sealing member (3) comprises two stacked sealing rings, and corresponding sides of the two sealing rings are each provided with a diaphragm groove (13), and the diaphragm (5) is accommodated in the diaphragm groove (13) between the two sealing rings.

4. The electrolytic cell according to claim 3, characterized in that The sealing element (3) is an annular structure made of plastic or fiber-reinforced plastic; the thickness of the sealing ring is 1-20 mm, the depth of the flow channel (12) is 1-10 mm, and the depth of the diaphragm groove (13) is 0.1-1 mm.

5. The electrolytic cell according to claim 1, characterized in that The bipolar plate (2) comprises a reaction zone (21) located in the central area and a sealing zone (22) located in the edge part, and the sealing zone (22) is provided with the liquid inlet (7) and the liquid outlet (9).

6. The electrolytic cell according to claim 5, characterized in that The bipolar plate (2) is a double-sided mastoid structure having a plurality of mastoids (8) on both sides; Alternatively, the bipolar plate (2) is a plate mesh structure in which a porous mesh is welded on both sides of a flat plate.

7. The electrolytic cell according to claim 6, characterized in that The bipolar plate (2) is made of carbon steel, stainless steel, carbon steel plated with nickel, pure nickel or a graphite composite material, and the thickness of the bipolar plate (2) is 1-10 mm.

8. The electrolytic cell according to claim 6, characterized in that The porous meshes on both sides of the bipolar plate (2) are obtained by stretching carbon steel, stainless steel, carbon steel plated with nickel or pure nickel plate, and the thickness of the porous mesh is 1-5 mm.

9. The electrolytic cell according to claim 1, characterized in that The diaphragm (5) is made of PPS cloth or a composite diaphragm.

10. The electrolytic cell according to any one of claims 1 to 9, characterized in that: The multiple electrolytic cells are stacked in sequence, and two adjacent electrolytic cells share one bipolar plate (2). End pressure plates are provided at both ends of the multiple electrolytic cells, and the multiple electrolytic cells are tightened and fixed by screws.

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