Channel structure of an alkaline electrolyzer and alkaline electrolyzer
By designing alkaline solution and gas-liquid channels of varying diameters in the alkaline electrolytic cell, combined with a PTFE inner liner, the problems of uneven electrolyte distribution and overheating were solved, achieving a more efficient and safer electrolysis process.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CRRC ZHUZHOU ELECTRIC LOCOMOTIVE RESEARCH INSTITUTE CO LTD
- Filing Date
- 2025-07-17
- Publication Date
- 2026-07-07
Smart Images
Figure CN224467940U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of alkaline electrolytic cell technology, specifically relating to a channel structure and an alkaline electrolytic cell. Background Technology
[0002] An alkaline electrolyzer is a core device for producing hydrogen by electrolyzing an alkaline aqueous solution (usually a 20%-30% KOH or NaOH solution). Its working principle is based on an electrochemical reaction and mainly consists of electrodes, a diaphragm, and an electrolyte. The electrolyte is evenly distributed to each electrolysis chamber through flow channels designed for the electrodes, ensuring thorough wetting of the electrodes and diaphragm. To increase the capacity of individual units, significantly reduce the unit cost of hydrogen production, better adapt to market demands, and meet the needs of renewable energy consumption in large-scale applications, alkaline electrolyzers are gradually developing towards larger scales, with alkaline electrolyzer units exceeding 1,000 cubic meters becoming increasingly common.
[0003] The trend towards larger alkaline electrolyzers necessitates an increase in the number of electrolysis chambers and the overall volume of the electrolyzer, resulting in excessively long electrolyzers and presenting new safety and efficiency challenges. One major issue is that the increased number of electrolysis chambers distributing the alkali solution leads to uneven distribution, further resulting in uneven overall temperature distribution within the electrolyzer. This can cause localized overheating in individual electrolysis chambers, exceeding the diaphragm's temperature tolerance and potentially causing diaphragm burn-through. This can also lead to cross-contamination of hydrogen and oxygen, posing a safety hazard to the electrolyzer.
[0004] Patent application CN118685803A discloses a flow channel structure and an alkaline electrolyzer. The flow channel structure includes an electrode body with an inlet and an outlet. Dot-shaped turbulence-inducing structural units are distributed on the electrode body, forming fluid channels. These units include first-stage, second-stage, and third-stage turbulence-inducing structural units, which together form branching channels on the electrode body. Essentially similar to the nipple-shaped flow channel design, both aim to create turbulence and improve the lateral distribution of the electrolyte; however, they also suffer from similar problems. Utility Model Content
[0005] The technical problem to be solved by this utility model is to provide a channel structure and an alkaline electrolytic cell, which has a simple structure and higher uniformity of electrolyte distribution.
[0006] This utility model embodiment provides a channel structure for an alkaline electrolytic cell, including an alkaline liquid channel and a gas-liquid channel. The alkaline liquid channel is provided with an alkaline liquid inlet, and the gas-liquid channel is provided with a gas-liquid outlet. The alkaline liquid enters the alkaline liquid channel from the alkaline liquid inlet, then flows through the electrolysis chamber, reaches the gas-liquid channel, and flows out from the gas-liquid outlet.
[0007] Along the flow direction of the alkali solution, the aperture of the alkali solution channel gradually decreases;
[0008] Along the gas-liquid flow direction, the aperture of the gas-liquid channel gradually increases, and the alkaline inlet and gas-liquid outlet are located on the same side of the alkaline electrolytic cell; or,
[0009] Along the gas-liquid flow direction, the aperture of the gas-liquid channel gradually decreases, and the alkaline inlet and gas-liquid outlet are located on both sides of the alkaline electrolytic cell.
[0010] Preferably, the aperture of the gas-liquid channel gradually increases along the gas-liquid flow direction, and the alkaline inlet and the gas-liquid outlet are located on the same side of the alkaline electrolytic cell.
[0011] Preferably, the alkali channel and / or gas-liquid channel is a segmented differential channel, comprising multiple differential channels connected in segments.
[0012] Preferably, the ratio of the cross-sectional areas of adjacent different-diameter channels is 0.6-0.8:1.
[0013] Preferably, the cross-sectional area of the gas-liquid channel is not less than the cross-sectional area of the alkali channel.
[0014] Preferably, the ratio of the maximum cross-sectional area of the alkali channel to the minimum cross-sectional area of the gas-liquid channel is 0.9-1.1:1.
[0015] Preferably, the ratio of the maximum cross-sectional area of the alkali channel to the minimum cross-sectional area of the gas-liquid channel is 1:1.
[0016] Preferably, the cross-sections of the gas-liquid channel and the alkali channel are circular or rectangular.
[0017] Preferably, the gas-liquid channel and the alkali channel have circular cross-sections;
[0018] The alkaline solution channel comprises three segments connected by different diameter channels, with a diameter ratio of 28:24:20.
[0019] The gas-liquid channel comprises three segments connected by different diameter channels, with a diameter ratio of 36:32:28.
[0020] This utility model provides an alkaline electrolytic cell, including an end plate, an end electrode plate, and multiple electrolytic chambers located between the end plate and the end electrode plate. Each electrolytic chamber includes a cathode, a diaphragm, and an anode. Each electrolytic chamber is separated by a bipolar plate. The bipolar plate is provided with alkaline solution through holes and gas-liquid through holes. Multiple alkaline solution through holes and gas-liquid through holes are combined to form the channel structure of the alkaline electrolytic cell.
[0021] The beneficial effects of this invention are as follows: Through a tiered segmented design of the bipolar plate frame channels, and by assembling processes to create either reduced or enlarged alkali channels and gas-liquid channels, fluid simulation calculations, combined with electrolyzers of different flow patterns (U-shaped and Z-shaped flow structures), significantly improve the uniform distribution of alkali in alkaline electrolyzers. The electrolyzer temperature is carried away by the circulating alkali cooling system; the more uniform the alkali distribution, the higher the temperature consistency between different electrolysis chambers, resulting in lower energy consumption and higher efficiency. Simultaneously, it avoids the safety issue of localized high-temperature burn-through of the diaphragm, preventing hydrogen-oxygen cross-contamination and explosion. This invention achieves the above structural form using PTFE packing of different annular sizes, reducing processing costs, solving the problem of standardized bipolar plate components, and addressing channel corrosion issues. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the alkaline electrolytic cell of this utility model.
[0023] Figure 2 This is a schematic diagram of the channel structure of the alkaline electrolytic cell in Example 1.
[0024] Figure 3 The pressure drop cloud map (a), velocity distribution cloud map (b), and flow distribution map of different chambers (c) are for Example 1.
[0025] Figure 4 This is a schematic diagram of the channel structure of the alkaline electrolyzer in Comparative Example 1.
[0026] Figure 5 The pressure drop contour map (a), velocity distribution contour map (b), and flow distribution map (c) of different compartments are shown in Comparative Example 1.
[0027] Figure 6 This is a schematic diagram of the channel structure of the alkaline electrolyzer in Comparative Example 2.
[0028] Figure 7 The pressure drop contour map (a), velocity distribution contour map (b), and flow distribution map of different compartments (c) are shown in Comparative Example 2.
[0029] Figure 8 This is a schematic diagram of the channel structure of the alkaline electrolytic cell in Example 2.
[0030] Figure 9 The pressure drop cloud map (a), velocity distribution cloud map (b), and flow distribution map of different chambers (c) are for Example 2.
[0031] Figure 10 This is a schematic diagram of the channel structure of the alkaline electrolyzer in Comparative Example 3.
[0032] Figure 11The pressure drop contour map (a), velocity distribution contour map (b), and flow distribution map (c) of different compartments are shown in Comparative Example 3.
[0033] Figure 12 This is a schematic diagram of the channel structure of the alkaline electrolyzer in Comparative Example 4.
[0034] Figure 13 The pressure drop contour map (a), velocity distribution contour map (b), and flow distribution map of different compartments (c) are shown in Comparative Example 4.
[0035] Figure 14 This is a schematic diagram of the cross-sectional structure of the channel structure of an alkaline electrolyzer.
[0036] In the diagram, 1 is the end plate, 2 is the bipolar plate, 3 is the cathode, 4 is the diaphragm, 5 is the anode, 6 is the end plate, 7 is the gas-liquid channel, 8 is the alkali channel, 9 is the alkali inlet, 10 is the gas-liquid outlet, 11 is the electrolysis chamber, and 12 is the inner liner. Detailed Implementation
[0037] An alkaline electrolytic cell includes an end plate 1, an end electrode plate 6, and a plurality of electrolytic chambers 11 located between the end plate 1 and the end electrode plate 6. Each electrolytic chamber 11 includes a cathode 3, a diaphragm 4, and an anode 5. Each electrolytic chamber 11 is separated by a bipolar plate 2. The bipolar plate 2 is provided with alkaline solution passages and gas-liquid passages. A combination of a plurality of alkaline solution passages forms an alkaline solution channel 8, and a combination of a plurality of gas-liquid passages forms a gas-liquid channel 7.
[0038] The end plate 1 serves to fix and support the electrolyte. Through holes are provided on the end plate 1 and / or the end electrode plate to provide an alkali inlet 9 and / or a gas-liquid outlet 10. The alkali solution is pumped into the alkaline electrolytic cell by an alkali circulation pump. The alkali solution enters the cell through the alkali inlet 9, flows through the alkali channel 8, and is distributed to each electrolysis chamber 11. Under the influence of current, an electrochemical reaction occurs at the electrodes, generating oxygen at the anode and hydrogen at the cathode. The gas and alkali solution then converge and flow out through the gas-liquid channel 7 from the gas-liquid outlet 10, entering a gas-liquid separator.
[0039] Example 1
[0040] like Figure 2 As shown, an alkaline electrolytic cell has a channel structure including an alkaline solution channel 8 and a gas-liquid channel 7. The alkaline solution channel 8 is provided with an alkaline solution inlet 9, and the gas-liquid channel 7 is provided with a gas-liquid outlet 10. The alkaline solution enters the alkaline solution channel 8 from the alkaline solution inlet 9, then flows through the electrolysis chamber 11, reaches the gas-liquid channel 7, and flows out from the gas-liquid outlet 10.
[0041] Along the flow direction of the alkali solution, the aperture of the alkali solution channel 8 gradually decreases;
[0042] Along the gas-liquid flow direction, the aperture of the gas-liquid channel 7 gradually increases, and the alkaline inlet 9 and the gas-liquid outlet 10 are located on the same side of the alkaline electrolytic cell.
[0043] The flow path of the alkali solution in Example 1 is U-shaped.
[0044] Along the flow direction of the alkali solution, the aperture of the alkali solution channel 8 gradually decreases. This gradual decrease in aperture can be linear or a gradient decrease, preferably a gradient decrease. Figure 2 As shown, the alkali channel 8 and / or the gas-liquid channel 7 are segmented channels with varying diameters, comprising multiple segments of different diameter channels connected together. Figure 2 The number of differential channels shown is 3, but other numbers are also possible. The number needs to be determined based on the total number of electrolysis chambers 11 in the alkaline electrolyzer.
[0045] The ratio of the cross-sectional areas of adjacent different-diameter channels in this invention is 0.6-0.8:1, that is, among adjacent different-diameter channels, the ratio of the cross-sectional areas of the different-diameter channel with the smaller cross-sectional area to the different-diameter channel with the larger cross-sectional area is 0.6-0.8:1.
[0046] The cross-sectional area of the gas-liquid channel 7 is not less than the cross-sectional area of the alkaline channel 8, that is, the cross-sectional area of any position of the gas-liquid channel 7 is not less than the cross-sectional area of any position of the alkaline channel 8.
[0047] The ratio of the maximum cross-sectional area of the alkali channel 8 to the minimum cross-sectional area of the gas-liquid channel 7 is 0.9-1.1:1, preferably, the ratio of the maximum cross-sectional area of the alkali channel 8 to the minimum cross-sectional area of the gas-liquid channel 7 is 1:1.
[0048] The gas-liquid channel 7 and the alkali channel 8 have circular or rectangular cross-sections. Preferably, the gas-liquid channel 7 and the alkali channel 8 have circular cross-sections.
[0049] Specifically, the cross-section of the alkali channel 8 is circular, comprising three segments of different diameter channels connected together, with a diameter ratio of 28mm:24mm:20mm; the cross-section of the gas-liquid channel 7 is circular, comprising three segments of different diameter channels connected together, with a diameter ratio of 36mm:32mm:28mm.
[0050] like Figure 14As shown, to easily and conveniently achieve variations in orifice diameter within the same channel, through-holes of uniform diameter can be opened on the bipolar plate 2. This makes fabrication easier, reduces product inconsistencies, and minimizes processing complexity and difficulty. Then, multiple inner liner tubes 12 with different orifice diameters are installed inside the channel, controlling the channel's orifice diameter through the orifice diameter of the inner liner tubes 12. The inner liner tubes 12 can be made of PTFE, which is resistant to strong alkalis, high temperatures, and corrosion, thus forming a stepped, segmented channel structure. During assembly, the alkali channel 8 and gas-liquid channel 7 on the bipolar plate 2 are filled in batches, avoiding the problem of inconsistent processing of the bipolar plate 2 structural components, reducing processing costs, and facilitating standardization. Simultaneously, using PTFE as the inner liner solves the problem of easy corrosion of the alkali channel.
[0051] Figure 3 As shown, this utility model adopts a structure in which the alkaline channel 8 is segmented and reduced along the fluid flow direction. This structure offsets the flow velocity change by changing the cross-sectional area, actively controls the flow velocity distribution, makes the static pressure tend to be gentle, and increases the flow field's resistance to disturbance, thus achieving uniform flow distribution. At the same time, the structure of the gas-liquid channel 7 being segmented and expanded along the flow direction controls the pressure deviation of different electrolysis chambers, achieving the effect of uniform flow distribution.
[0052] A flow distribution simulation was performed on this structure, and the results are shown below. Figure 3 The maximum and minimum flow deviation (range) is 1.18, indicating that the overall flow distribution is relatively uniform.
[0053] Comparative Example 1
[0054] like Figure 4 As shown, the difference between Comparative Example 1 and Example 1 lies in that the aperture of the gas-liquid channel 7 gradually increases along the gas-liquid flow direction. The cross-section of the gas-liquid channel 7 is circular, comprising three segments of different diameter channels connected together. The diameter ratio of the different diameter channels is still 36:32:28, and everything else is the same as in Example 1.
[0055] A flow distribution simulation was performed on this structure, and the results are shown below. Figure 5 The maximum and minimum deviations (range) of the flow rate are 1.98.
[0056] Comparative Example 2
[0057] like Figure 6 As shown, the difference between Comparative Example 2 and Example 1 lies in that the aperture of the alkali channel 8 is the same along the flow direction of the alkali solution; the aperture of the gas-liquid channel 7 is the same along the flow direction of the gas and liquid; and the alkali inlet 9 and the gas-liquid outlet 10 are located on the same side of the alkaline electrolytic cell. The cross-section of the alkali channel 8 is circular with an aperture of 24, and the cross-section of the gas-liquid channel 7 is circular with an aperture of 32. Other aspects are the same as in Example 1.
[0058] A flow distribution simulation was performed on this structure, and the results are shown below. Figure 7 The maximum and minimum deviations (range) of the flow rate are 1.29.
[0059] Example 2
[0060] like Figure 8 As shown, the difference between Example 2 and Example 1 is that the aperture of the gas-liquid channel 7 gradually decreases along the gas-liquid flow direction. The alkaline solution inlet 9 and the gas-liquid outlet 10 are located on opposite sides of the alkaline electrolytic cell. That is, the alkaline solution is Z-shaped overall.
[0061] The gas-liquid channel 7 has a circular cross-section and includes three segments of different diameter channels connected together. The diameter ratio of the different diameter channels is still 36:32:28, and the rest is the same as in Example 1.
[0062] A flow distribution simulation was performed on this structure, and the results are shown below. Figure 9 The maximum and minimum deviations (range) of the flow rate are 1.21.
[0063] Comparative Example 3
[0064] like Figure 10 As shown, the difference between Comparative Example 3 and Example 1 is that the aperture of the gas-liquid channel 7 gradually increases along the gas-liquid flow direction. The alkaline solution inlet 9 and the gas-liquid outlet 10 are located on opposite sides of the alkaline electrolytic cell. That is, the alkaline solution is Z-shaped overall.
[0065] The gas-liquid channel 7 has a circular cross-section and includes three segments of different diameter channels connected together. The diameter ratio of the different diameter channels is still 36:32:28, and the rest is the same as in Example 1.
[0066] A flow distribution simulation was performed on this structure, and the results are shown below. Figure 11 The maximum and minimum deviations (range) of the flow rate are 1.33.
[0067] Comparative Example 4
[0068] like Figure 12 As shown, the difference between Comparative Example 4 and Comparative Example 2 is that the alkali inlet 9 and the gas-liquid outlet 10 are located on opposite sides of the alkaline electrolytic cell. The alkali solution is Z-shaped overall. Everything else is the same as Comparative Example 2.
[0069] A flow distribution simulation was performed on this structure, and the results are shown below. Figure 13 The maximum and minimum deviations (range) of the flow rate are 1.90.
[0070] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of protection of this application is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of one or more embodiments of this application as described above, which are not provided in detail for the sake of brevity.
[0071] One or more embodiments in this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments in this application should be included within the protection scope of this application.
Claims
1. A passage structure of an alkaline electrolyzer, characterized by, The alkali solution channel (8) is provided with an alkali solution inlet (9), and the gas-liquid channel (7) is provided with a gas-liquid outlet (10); alkali solution enters the alkali solution channel (8) from the alkali solution inlet (9), then flows through the electrolytic cell (11), reaches the gas-liquid channel (7), and flows out from the gas-liquid outlet (10); The pore diameter of the alkali solution channel (8) gradually decreases along the flow direction of the alkali solution; The pore diameter of the gas-liquid channel (7) gradually increases along the flow direction of the gas-liquid, and the alkali solution inlet (9) and the gas-liquid outlet (10) are located on the same side of the alkaline electrolytic cell; or, The pore diameter of the gas-liquid channel (7) gradually decreases along the flow direction of the gas-liquid, and the alkali solution inlet (9) and the gas-liquid outlet (10) are located on the same side of the alkaline electrolytic cell; or, 2. The passage structure of an alkaline electrolyzer according to claim 1, wherein The pore diameter of the gas-liquid channel (7) gradually increases along the flow direction of the gas-liquid, and the alkali solution inlet (9) and the gas-liquid outlet (10) are located on the same side of the alkaline electrolytic cell.
3. The passage structure of an alkaline electrolyzer according to claim 1, wherein The alkali solution channel (8) and / or the gas-liquid channel (7) are segmented variable-diameter channels, comprising a plurality of variable-diameter channel segments.
4. The passage structure of an alkaline electrolyzer according to claim 3, wherein The cross-sectional area ratio of adjacent variable-diameter channels is 0.6-0.8:
1.
5. The channel structure of an alkaline electrolyzer according to any one of claims 1 to 4, characterized in that The cross-sectional area of the gas-liquid channel (7) is not less than the cross-sectional area of the alkali solution channel (8).
6. The channel structure of an alkaline electrolyzer according to any one of claims 1 to 4, wherein The ratio of the maximum cross-sectional area of the alkali solution channel (8) to the minimum cross-sectional area of the gas-liquid channel (7) is 0.9-1.1:
1.
7. The channel structure of an alkaline electrolyzer according to any one of claims 1 to 4, characterized in that The ratio of the maximum cross-sectional area of the alkali solution channel (8) to the minimum cross-sectional area of the gas-liquid channel (7) is 1:
1.
8. The channel structure of an alkaline electrolyzer according to any one of claims 1 to 4, wherein The cross-section of the gas-liquid channel (7) and the alkali solution channel (8) is circular or rectangular.
9. The passage structure of an alkaline electrolyzer according to claim 8, wherein The cross-section of the gas-liquid channel (7) and the alkali solution channel (8) is circular; The alkali solution channel (8) comprises three variable-diameter channel segments connected in series, and the diameter ratio of the variable-diameter channels is 28:24:20; The gas-liquid channel (7) comprises three variable-diameter channel segments connected in series, and the diameter ratio of the variable-diameter channels is 36:32:
28.
10. An alkaline electrolyzer characterized by, The alkali solution channel (8) and / or the gas-liquid channel (7) are segmented variable-diameter channels, comprising a plurality of variable-diameter channel segments.