An electrolytic cell

Abstract

This invention belongs to the field of water electrolysis for hydrogen production technology, and specifically relates to an electrolyzer. It includes a sealing element, electrode I, a diaphragm, electrode II, and bipolar plates. The two bipolar plates are sealed together by the sealing element. The diaphragm is disposed between the two bipolar plates, with two reaction chambers formed on each side of the diaphragm. Electrode I and electrode II are respectively disposed within the two reaction chambers. The bipolar plates are provided with an inlet and an outlet. The sealing element has an inlet channel and an outlet channel for connecting the reaction chambers with the inlet and outlet. This invention combines the bipolar plates and the electrode frame into a single fabricated component, eliminating the welding process between the electrode frame and the electrode plates. Furthermore, because this invention does not use a thick electrode frame, it significantly reduces the material and processing costs of the electrode frame.

Description

Technical Field

[0001] This invention belongs to the field of water electrolysis for hydrogen production technology, and specifically relates to an electrolyzer. Background Technology

[0002] Hydrogen is not only an ideal clean energy carrier but also an extremely important chemical raw material. Hydrogen produced by electrolyzing water using renewable energy sources is known as "green hydrogen" and represents the future direction of the energy and chemical industries. Hydrogen production technologies through water electrolysis are mainly divided into alkaline water electrolysis (AWE), proton exchange membrane (PEM), and solid oxide electrolysis (SOE). Alkaline water electrolysis is simple in structure, technologically mature, and has low cost, making it the most widely used water electrolysis technology in 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, the core component of the device, is mainly composed of end pressure plates, bipolar plates 2, electrodes, a diaphragm 5, sealing gaskets, and bolts. During operation, the liquid inlet is split into two, entering the reaction chambers on either side of the diaphragm 5. The electrode tank outputs liquid through two channels to gas-liquid separators I15 and II14, thereby producing oxygen and hydrogen. The electrolyte in gas-liquid separators I15 and II14 is collected and recycled back into the electrolyzer. It is estimated that the bipolar plates account for 44% of the manufacturing cost of the electrolyzer, sealing materials 8%, end pressure plates 5%, electrodes 28%, and the diaphragm 8%. The bipolar plates are the key component affecting the manufacturing cost of the electrolyzer. To meet the requirements of high-temperature and strong alkali corrosion, high-pressure alkaline gas-liquid sealing, porous electrode current collection, and electrolyte and gas flow, the bipolar plate 2 of the electrolyzer is currently generally made of thin carbon steel plate precision stamped into a double-sided protruding plate, which is then welded together with the thick carbon steel electrode frame 1 and then subjected to overall nickel plating. The difference in thickness between the electrode frame 1 and the bipolar plate 2 is because after the bipolar plate 2 is stamped into a double-sided protruding plate, the protrusions occupy a certain thickness space, which can accommodate the flow of electrolyte. However, this results in a long bipolar plate processing procedure, and the electrode frame 1 and electrode plate 2 need to be processed separately and then welded into a whole, leading to high material / processing costs. This directly increases the cost of alkaline water electrolysis hydrogen production equipment and affects the large-scale application of alkaline water electrolysis hydrogen production technology. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide an electrolyzer that solves the problem of high manufacturing and usage costs of existing alkaline water electrolysis for hydrogen production.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides an electrolytic cell, including a sealing element, electrode I, a diaphragm, electrode II, and bipolar plates. The two bipolar plates are sealed together by the sealing element. The diaphragm is disposed between the two bipolar plates and fixed to the sealing element. Two reaction chambers are formed on both sides of the diaphragm. Electrode I and electrode II are respectively disposed in the two reaction chambers. The bipolar plates are provided with an inlet and an outlet. The sealing element is provided with an inlet channel for communicating between the reaction chamber and the inlet and an outlet channel for communicating between the reaction chamber and the outlet.

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

[0008] The sealing element includes two stacked sealing rings, each with a diaphragm groove on its corresponding side, and the diaphragm is housed in the diaphragm groove between the two sealing rings.

[0009] The sealing element is a ring 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 in the central region and a sealing zone in the edge region, with the inlet and outlet of the liquid in the sealing zone.

[0011] The bipolar plate is a bifacial papillary structure with multiple papillae on both sides;

[0012] Alternatively, the bipolar plate may be a plate-mesh structure in which a porous mesh is welded to both sides of a flat plate.

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

[0014] The perforated mesh on both sides of the bipolar plate is made of carbon steel, stainless steel, nickel-plated carbon steel, or pure nickel plate through stretching, and the thickness of the perforated mesh is 1-5mm.

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

[0016] Multiple electrolytic cells are stacked sequentially, and two adjacent electrolytic cells share a bipolar plate. End pressure plates are provided at both ends of the multiple electrolytic cells, and the two end pressure plates are tightened and fixed by screws passing through the multiple electrolytic cells.

[0017] The advantages and beneficial effects of the present invention are as follows: The electrolytic cell provided by the present invention combines the bipolar plate and the electrode frame into a single processed part, eliminating the welding process between the electrode frame and the electrode plate; at the same time, since the present invention does not use a thick electrode frame, the material cost and processing cost of the electrode frame are greatly reduced.

[0018] In traditional electrolytic cells, the flow channel between the inlet / outlet holes and the reaction zone is located on the electrode frame. This invention moves it to the sealing element, further reducing the processing time of the electrode frame and electrode plate. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a traditional electrolytic cell.

[0020] Figure 2 This is a schematic diagram of the explosion-proof design of a traditional electrolytic cell;

[0021] Figure 3 This is a schematic diagram of the structure of an electrolytic cell according to the present invention;

[0022] Figure 4 This is an exploded view of an electrolytic cell according to the present invention;

[0023] Figure 5 This is a schematic diagram of the bipolar plate in this invention;

[0024] Figure 6 This is a schematic diagram of the sealing element in this invention.

[0025] In the diagram: 1-Electrode frame, 2-Bipolar plate, 3-Seal, 4-Electrode I, 5-Diaphragm, 6-Electrode II, 7-Inlet, 8-Papillary, 9-Outlet, 10-Annular sealing line, 11-Traditional bipolar plate weld joint, 12-Flow channel, 13-Diaphragm groove, 14-Gas-liquid separator II, 15-Gas-liquid separator I, 21-Reaction zone, 22-Sealing zone. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] like Figure 3-4As shown, this invention provides an electrolytic cell, including a sealing element 3, electrode I 4, diaphragm 5, electrode II 6, and bipolar plates 2. The two bipolar plates 2 are sealed together by the sealing element 3. The diaphragm 5 is disposed between the two bipolar plates 2, with two reaction chambers formed on both sides of the diaphragm 5. Electrode I 4 and electrode II 6 are respectively disposed within the two reaction chambers. The bipolar plates 2 are provided with an inlet 7 and an outlet 9. The sealing element 3 is provided with an inlet channel for communication between the reaction chamber and the inlet 7, and an outlet channel for communication between the reaction chamber and the outlet 9. This invention combines the bipolar plates and the electrode frame into a single processed component, eliminating the welding process between the electrode frame and the electrode plates. Furthermore, the inlet and outlet channels on the sealing element further reduce the processing time of the electrode frame and the electrode plates.

[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 region and a sealing zone 22 located at the edge. The sealing zone 22 is provided with an inlet 7 and an outlet 9. In this embodiment, the bipolar plate 2 is a double-sided papillary structure with multiple papillae 8 on both sides. In an embodiment of the present invention, the bipolar plate 2 is made of carbon steel, stainless steel, nickel-plated carbon steel, pure nickel, or graphite composite material. The thickness of the bipolar plate 2 is 1-10 mm, preferably 2-4 mm.

[0029] Alternatively, the bipolar plate 2 can also be a plate-mesh structure with perforated mesh welded to both sides of a flat plate. The perforated mesh on both sides of the bipolar plate 2 is made of carbon steel, stainless steel, nickel-plated carbon steel, or pure nickel plate and is obtained by stretching. The thickness of the perforated 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 integral structure of the bipolar plate and the pole frame formed by integral stamping, stamping + machining, machining + welding perforated mesh, etc.

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

[0032] In embodiments of the present invention, the sealing element 3 includes two stacked sealing rings, each with a diaphragm groove 13 on its corresponding side, and a diaphragm 5 is housed within the diaphragm groove 13 between the two sealing rings. Specifically, the sealing element 3 is 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 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.

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

[0034] Based on the above embodiments, multiple electrolytic cells are stacked sequentially, and two adjacent electrolytic cells share a bipolar plate 2. End pressure plates are provided at both ends of the multiple electrolytic cells, and the two end pressure plates are tightened and fixed by screws that pass through the multiple electrolytic cells.

[0035] Example 1

[0036] The bipolar plate and frame are integrally formed by laser cutting, stamping, and electroplating with nickel from 3mm carbon steel plate, with a reaction area of ​​500cm². 2 The sealing component 3 is obtained by CNC machining of a 4mm glass fiber reinforced PTFE sheet. The hydrogen evolution electrode (electrode II 6) uses a nickel mesh coated with Raney nickel, the oxygen evolution electrode (electrode I 4) uses a nickel mesh, the diaphragm 5 uses PPS cloth, and 40mm thick end pressure plates are used on both sides. Figure 3 The cells are stacked in the order shown and tightened by a screw to obtain a novel nipple-shaped electrolytic cell with 10 chambers. The electrolytic cell is installed in an electrolytic water testing device. The electrolyte is a 30% KOH solution, the operating temperature is 90℃, the operating pressure is 0.6MPa, and the electrolysis current is 125A. The processing time and voltage of the electrolytic cell are recorded.

[0037] In this embodiment, the processing time for the integrated bipolar plate frame is as follows: laser cutting 1 min, stamping 0.5 min, electroplating 30 min, for a total of 31.5 min. The processing time for the sealing component is: CNC machining 5 min; the electrolytic cell voltage is 18.13V; the DC power consumption of the electrolytic cell is 4.33 kWh / Nm³. 3 H2

[0038] Example 2

[0039] A 2mm thick stretched nickel mesh is laser-cut to obtain a circular porous mesh. A 3mm thick carbon steel plate is laser-cut, stamped, double-sided welded with the stretched nickel mesh, and electroplated with nickel to obtain an integrated bipolar plate frame. The reaction area is 500cm². 2The sealing component 3 is obtained by CNC machining of a 3mm glass fiber reinforced PTFE sheet. The hydrogen evolution electrode uses a nickel mesh coated with Raney nickel, the oxygen evolution electrode uses a nickel mesh, the diaphragm uses PPS cloth, and 40mm thick end pressure plates are used on both sides. Figure 3 The cells are stacked in the order shown and tightened by a screw to obtain a new type of plate-mesh electrolytic cell with 10 compartments. The electrolytic cell is installed in an electrolytic water testing device. The electrolyte is a 30% KOH solution, the operating temperature is 90℃, the operating pressure is 0.6MPa, and the electrolysis current is 125A. The processing time and voltage of the electrolytic cell are recorded.

[0040] In this embodiment, the processing time for the integrated bipolar plate frame is as follows: laser cutting of stretched nickel mesh 1 min, laser cutting of bipolar plate 1 min, stamping 0.5 min, welding of stretched nickel mesh 2 min, electroplating 30 min, for a total of 34.5 min. The processing time for the sealing component is: CNC machining 5 min; electrolytic cell voltage: 17.95V; electrolytic cell DC power consumption: 4.29 kWh / Nm³. 3 H2

[0041] Comparative Example

[0042] Bipolar plate 2 is obtained by laser cutting and stamping of 3mm carbon steel plate, and electrode frame 1 is obtained by laser cutting and CNC machining of 10mm carbon steel plate. The bipolar plate 2 and electrode frame 1 are then welded together and electroplated with nickel to obtain a single bipolar plate and electrode frame assembly with a reaction area of ​​500 cm². 2 The sealing component 3 is obtained by CNC machining of a 3mm glass fiber reinforced PTFE sheet. The hydrogen evolution electrode uses a nickel mesh coated with Raney nickel, the oxygen evolution electrode uses a nickel mesh, the diaphragm uses PPS cloth, and 40mm thick end pressure plates are used on both sides. Figure 1 The cells are stacked in the order shown and tightened by a screw to form a conventional electrolytic cell with 10 chambers. The electrolytic cell is then installed in a water electrolysis test device. The electrolyte is a 30% KOH solution, the operating temperature is 90℃, the operating pressure is 0.6MPa, and the electrolysis current is 125A. The processing time and voltage of the electrolytic cell are recorded.

[0043] The processing time for the integrated bipolar plate and frame is as follows: bipolar plate laser cutting 1 min, bipolar plate stamping 0.5 min, frame laser cutting 2 min, frame CNC machining 2 h, welding 30 min, electroplating 30 min, for a total of 183.5 min. The processing time for the sealing components is: CNC machining 3 min; electrolytic cell voltage: 18.18V; electrolytic cell DC power consumption: 4.35 kWh / Nm³. 3 H2

[0044] It is evident that the processing time for bipolar plates and frames in traditional electrolytic cells is long and the processing cost is high; however, the processing time for the integrated bipolar plate and frame component of the electrolytic cell of the present invention is significantly reduced, which can greatly reduce the processing cost of electrolytic cells.

[0045] This invention provides an electrolytic cell in which the bipolar plates and electrode frames are integrated into a single machined component, eliminating the need for welding the electrode frames and plates. Furthermore, because this invention does not use thick electrode frames, it significantly reduces the material and processing costs of the electrode frames. In traditional electrolytic cells, the flow channel between the inlet / outlet ports and the reaction zone is located on the electrode frame; this invention moves this channel to the sealing component, further reducing the processing time for the electrode frames and plates.

[0046] The above description is merely an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, extensions, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. An electrolytic cell, characterized in that, It includes a sealing element (3), electrode I (4), diaphragm (5), electrode II (6) and bipolar plate (2), wherein the two bipolar plates (2) are sealed and connected by the sealing element (3), the diaphragm (5) is disposed between the two bipolar plates (2) and fixed on the sealing element (3), and two reaction chambers are formed on both sides of the diaphragm (5). Electrode I (4) and electrode II (6) are respectively disposed in the two reaction chambers. The bipolar plate (2) is provided with an inlet (7) and an outlet (9); the sealing element (3) is provided with an inlet channel for connecting the reaction chamber with the inlet (7) and an outlet channel for connecting the reaction chamber with the outlet (9). The liquid inlet channel and liquid outlet channel on the sealing element (3) have the same structure, both including a transverse channel and a flow channel (12). The transverse channel is arranged axially on the sealing element (3), and the flow channel (12) is arranged radially on the side of the sealing element (3). The liquid entering from the liquid inlet (7) enters the reaction chamber through the transverse channel and the flow channel (12) of the liquid inlet channel in sequence, or the liquid in the reaction chamber flows into the liquid outlet (9) of the bipolar plate (2) through the flow channel (12) and the transverse channel of the liquid outlet channel. The sealing element (3) includes two stacked sealing rings, and each of the two sealing rings has a diaphragm groove (13) on its corresponding side. The diaphragm (5) is housed in the diaphragm groove (13) between the two sealing rings. The bipolar plate (2) includes a reaction zone (21) located in the central region and a sealing zone (22) located at the edge. The sealing zone (22) is provided with the liquid inlet (7) and the liquid outlet (9).

2. The electrolytic cell of claim 1, wherein, 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.

3. The electrolytic cell of claim 1, wherein, The bipolar plate (2) is a bifacial papillary structure with multiple papillae (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.

4. The electrolytic cell of claim 3, wherein, The bipolar plate (2) is made of carbon steel, stainless steel, nickel-plated carbon steel, pure nickel or graphite composite material, and the thickness of the bipolar plate (2) is 1-10 mm.

5. The electrolytic cell of claim 3, wherein, The perforated mesh on both sides of the bipolar plate (2) is made of carbon steel, stainless steel, nickel-plated carbon steel or pure nickel plate by stretching, and the thickness of the perforated mesh is 1-5mm.

6. The electrolytic cell of claim 1, wherein, The diaphragm (5) is made of PPS cloth or a composite diaphragm.

7. The electrolytic cell of any one of claims 1-6, wherein, Multiple electrolytic cells are stacked sequentially, and two adjacent electrolytic cells share a 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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