Flow channel structure of alkaline electrolyzer and alkaline electrolyzer

Abstract

This invention belongs to the field of water electrolysis hydrogen production technology, specifically relating to a flow channel structure and an alkaline electrolyzer, including an alkali solution channel and a gas-liquid channel. Both the alkali solution channel and the gas-liquid channel are equipped with corrosion-resistant insulating sleeves. The interior of each corrosion-resistant insulating sleeve forms a flow channel for the flow of alkali solution or gas-liquid. An opening is provided on the side of the corrosion-resistant insulating sleeve to allow communication between the interior of the sleeve and the electrolysis chamber. Furthermore, the inner diameter of the flow channel formed inside the corrosion-resistant insulating sleeve in the alkali solution channel gradually decreases along the direction of alkali solution flow. This invention can slow down metal corrosion, extend service life, reduce stray current conduction, improve current efficiency, optimize the alkali solution flow distribution in each electrolysis chamber, improve flow distribution uniformity and temperature uniformity, and reduce energy consumption.

Description

Technical Field

[0001] This utility model belongs to the field of water electrolysis hydrogen production technology, specifically relating to a flow channel structure and an alkaline electrolyzer. Background Technology

[0002] Hydrogen energy, as a zero-carbon emission energy source, is considered an ideal choice for sustainable development. Among various methods of hydrogen production through water electrolysis, alkaline electrolyzers have achieved industrial-scale production and are ready for large-scale application, making them the mainstream product for hydrogen production through water electrolysis. However, with the increasing size of alkaline electrolyzers, the number of electrolysis chambers and the overall volume of the electrolyzer are increasing, leading to higher performance and lifespan requirements for these cells.

[0003] However, existing alkaline electrolyzers generally have the following problems: ① The flow channels suffer from severe metal corrosion, affecting the lifespan of the alkaline electrolyzer; ② Stray current is a prominent problem, resulting in low current efficiency of the alkaline electrolyzer; ③ Uneven flow distribution between the electrolysis chambers affects the temperature uniformity of the alkaline electrolyzer and leads to high energy consumption. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a flow channel structure and an alkaline electrolytic cell, which aims to slow down metal corrosion, extend service life, improve current efficiency, optimize the alkaline solution flow distribution in each electrolysis chamber, improve the uniformity of flow distribution and temperature uniformity, and reduce energy consumption.

[0005] This utility model provides a flow channel structure for an alkaline electrolytic cell, including an alkali channel and a gas-liquid channel. Both the alkali channel and the gas-liquid channel are provided with corrosion-resistant insulating sleeves. The interior of the corrosion-resistant insulating sleeve forms a flow channel for the flow of alkali or gas-liquid. An opening is provided on the side of the corrosion-resistant insulating sleeve to allow the interior of the corrosion-resistant insulating sleeve to communicate with the electrolysis chamber. The inner diameter of the flow channel formed inside the corrosion-resistant insulating sleeve in the alkali channel gradually decreases along the direction of alkali flow.

[0006] Furthermore, the inner diameter of the flow channel formed inside the corrosion-resistant insulating sleeve installed in the alkali solution channel gradually decreases in a stepped manner along the direction of alkali solution flow, and the inner diameter of the flow channel in a single stepped region is the same.

[0007] Furthermore, the opening extends axially through both ends of the corrosion-resistant insulating sleeve.

[0008] Furthermore, the two sides of the opening are connected to the inner wall of the corrosion-resistant insulating sleeve by tie rods.

[0009] Furthermore, the connection between the corrosion-resistant insulating sleeve and the tie rod is located in the area opposite the opening on the inner wall of the corrosion-resistant insulating sleeve.

[0010] Furthermore, the alkali channel is composed of liquid inlets on all bipolar plates, and the gas-liquid channel is composed of gas-liquid outlets on all bipolar plates. A corrosion-resistant insulating sleeve is inserted into the liquid inlet and gas-liquid outlet of each bipolar plate. The corrosion-resistant insulating sleeves in the liquid inlets of all bipolar plates together form a flow channel for alkali flow, and the corrosion-resistant insulating sleeves in the gas-liquid outlets of all bipolar plates together form a flow channel for gas-liquid flow.

[0011] Furthermore, each of the adjacent gaskets of the bipolar plate is provided with a channel corresponding to the position of the liquid inlet and the gas-liquid inlet, a corrosion-resistant insulating sleeve is inserted into the liquid inlet and the gas-liquid inlet of a single bipolar plate, and at the same time, it is inserted into the channel of a gasket that is axially adjacent to the bipolar plate.

[0012] Furthermore, one end of the corrosion-resistant insulating sleeve is provided with a convex plate, and the gasket is provided with a positioning groove at the edge of the channel opening. The depth of the positioning groove is the same as the thickness of the convex plate, and the shape of the positioning groove is the same as the shape of the convex plate.

[0013] Furthermore, the convex plates are located on both sides of one end of the corrosion-resistant insulating sleeve.

[0014] This utility model also provides an alkaline electrolytic cell, which is provided with the flow channel structure of the alkaline electrolytic cell as described above.

[0015] The beneficial effects of this invention are that it can minimize or isolate direct contact between the alkaline solution and the metal channel during the flow process, effectively mitigating metal corrosion problems under the "alkaline solution-two-phase flow impact-strong oxidizing" environment and extending the service life of the alkaline electrolytic cell. Simultaneously, the corrosion-resistant insulating sleeve can significantly reduce stray current conduction to the bipolar plate metal frame, allowing more electrical energy to be used for effective water electrolysis, thereby improving the current efficiency of the alkaline electrolytic cell. Furthermore, the inner diameter of the flow channel formed inside the corrosion-resistant insulating sleeve in the alkaline solution channel gradually decreases along the alkaline solution flow direction, adjusting the flow resistance in the alkaline solution flow direction, thereby optimizing the alkaline solution flow distribution in each electrolysis chamber, improving flow distribution uniformity and temperature uniformity, and reducing energy consumption. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the first embodiment of the flow channel structure of the alkaline electrolytic cell of this utility model.

[0017] Figure 2 This is an exploded structural diagram of the bipolar plate, gasket, and corrosion-resistant insulating sleeve of this utility model.

[0018] Figure 3 (a) Figure 3 (b) Figure 3 (c) are schematic diagrams of the corrosion-resistant insulating sleeve structures with different inner diameters according to this utility model.

[0019] Figure 4 This is an axial schematic diagram of the corrosion-resistant insulating sleeve of this utility model without the protruding plate.

[0020] Figure 5 This is a comparison chart of electrolyte flow distribution in alkaline electrolytic cells with and without corrosion-resistant insulating sleeves.

[0021] Figure 6 This is a comparison chart of the current efficiency of alkaline electrolytic cells with and without corrosion-resistant insulating sleeves.

[0022] Figure 7 This is a partial schematic diagram of the corrosion-resistant insulating sleeve, bipolar plate, and gasket of this utility model before assembly.

[0023] Figure 8 This is a schematic diagram of the second embodiment of the flow channel structure of the alkaline electrolytic cell of this utility model.

[0024] Figure 9 This is a schematic diagram of another embodiment of the corrosion-resistant insulating sleeve of this utility model.

[0025] In the diagram: 1. Bipolar plate; 11. Liquid inlet; 12. Gas-liquid inlet; 13. Inlet channel to small chamber; 14. Outlet channel to small chamber; 2. Gasket; 21. Channel opening; 22. Positioning groove; 3. Corrosion-resistant insulating sleeve; 31. Opening; 32. Tie; 33. Protruding plate; 100. Alkali channel; 200. Gas-liquid channel. Detailed Implementation

[0026] like Figures 1-9As shown, this utility model provides a flow channel structure for an alkaline electrolytic cell, including an alkaline solution channel 100 and a gas-liquid channel 200. The alkaline solution channel 100 is connected to the cavity of the electrolysis chamber through an inlet flow channel 13, and the gas-liquid channel 200 is connected to the cavity of the electrolysis chamber through an outlet flow channel 14. Both the alkaline solution channel 100 and the gas-liquid channel 200 are provided with corrosion-resistant insulating sleeves 3. The interior of the corrosion-resistant insulating sleeves 3 forms a flow channel for the flow of alkaline solution or gas-liquid. Specifically, before the alkaline solution enters the electrolysis chamber, it flows along the interior of the corrosion-resistant insulating sleeves 3 in the alkaline solution channel 100, and after the gas-liquid flows out of the electrolysis chamber, it flows along the interior of the corrosion-resistant insulating sleeves 3 in the gas-liquid channel 200. The corrosion-resistant insulating sleeve 3 has an opening 31 on its side. The opening 31 of the corrosion-resistant insulating sleeve 3 in the alkali channel 100 corresponds to the position of the inlet flow channel 13, and the opening 31 of the corrosion-resistant insulating sleeve 3 in the gas-liquid channel 200 corresponds to the position of the outlet flow channel 14, so that the interior of the corrosion-resistant insulating sleeve 3 can communicate with the cavity of the corresponding electrolysis chamber. The inner diameter of the flow channel formed inside the corrosion-resistant insulating sleeve 3 in the alkali channel 100 gradually decreases along the direction of alkali flow. The corrosion-resistant insulating sleeve 3 can be made of polytetrafluoroethylene (PTFE), or other alkali-resistant and insulating materials, such as perfluoroalkoxyalkanes, polyvinylidene fluoride (PVDF), and other fluoropolymers, can be selected according to the actual working conditions.

[0027] This invention, by incorporating corrosion-resistant insulating sleeves 3 in the alkali solution channel 100 and the gas-liquid channel 200, minimizes or isolates direct contact between the alkali solution and the metal channels during flow, effectively mitigating metal corrosion under the "alkali solution-two-phase flow impact-strong oxidizing" environment and extending the service life of the alkaline electrolyzer. Simultaneously, the corrosion-resistant insulating sleeves 3 significantly reduce stray current conduction to the metal frame of the bipolar plate 1, allowing more electrical energy to be used for effective water electrolysis, thereby improving the current efficiency of the alkaline electrolyzer. Furthermore, the inner diameter of the flow channel formed within the corrosion-resistant insulating sleeves 3 in the alkali solution channel 100 gradually decreases along the alkali solution flow direction, adjusting the flow resistance in this direction, thereby optimizing the alkali solution flow distribution in each electrolysis chamber, improving flow distribution uniformity and temperature uniformity, and reducing energy consumption.

[0028] In this invention, the corrosion-resistant insulating sleeve 3, installed in the alkali channel 100, has an inner diameter that gradually decreases in a stepped manner along the alkali flow direction. The inner diameter of the flow channel within each stepped region is the same, ensuring effective alkali flow control and improving the flow uniformity of the electrolysis chamber. Compared to a continuously changing inner diameter design, the stepped inner diameter reduces the processing difficulty and requirements of the corrosion-resistant insulating sleeve 3. The specific number of steps can be selected according to the specifications of the electrolytic cell and the actual flow distribution requirements. Figure 1 and Figure 8The schematic diagram illustrates the flow channel structure of the alkali channel 100, which exhibits a three-level stepped change.

[0029] In one embodiment of this utility model, such as Figure 9 As shown, the size and position of the opening 31 correspond to the size and position of the flow channel 14 when entering the school or exiting the small chamber.

[0030] In a preferred embodiment of this utility model, such as Figure 3 As shown, the opening 31 axially extends through both ends of the corrosion-resistant insulating sleeve 3, which reduces the processing difficulty and precision of the corrosion-resistant insulating sleeve 3. Simultaneously, it reduces the difficulty of aligning the opening 31 with the inlet / outlet flow channel 13 or the outlet flow channel 14 during installation. The two sides of the opening 31 are connected to the inner wall of the corrosion-resistant insulating sleeve 3 by tie rods 32, and the connection point between the corrosion-resistant insulating sleeve 3 and the tie rods 32 is located in the area opposite the opening 31 to the inner wall of the corrosion-resistant insulating sleeve 3. Based on this design, the strength of the corrosion-resistant insulating sleeve 3 is improved, the stability of the opening 31 structure is maintained, and the reliability for long-term use is ensured.

[0031] The alkali channel 100 is composed of liquid inlets 11 disposed on all bipolar plates 1, and the gas-liquid channel 200 is composed of gas-liquid outlets 12 disposed on all bipolar plates 1. Specifically, the liquid inlets 11, gas-liquid outlets 12, inlet chamber flow channels 13 and outlet chamber flow channels 14 are all disposed on the electrode frame of the bipolar plates 1. One end of the inlet chamber flow channel 13 is connected to the liquid inlet 11, and the other end is connected to the inner side of the electrode frame. One end of the outlet chamber flow channel 14 is connected to the inner side of the electrode frame, and the other end is connected to the gas-liquid outlet 12.

[0032] Each bipolar plate 1 has a corresponding corrosion-resistant insulating sleeve 3 inserted into its liquid inlet 11 and gas-liquid outlet 12. The interiors of the corrosion-resistant insulating sleeves 3 in the liquid inlets 11 of all bipolar plates 1 collectively form a flow channel for the alkaline solution, and the interiors of the corrosion-resistant insulating sleeves 3 in the gas-liquid outlets 12 of all bipolar plates 1 collectively form a flow channel for the gas-liquid flow. This design not only facilitates the installation of corrosion-resistant insulating sleeves 3 during the assembly of the alkaline electrolytic cell, but also allows for the standardization and serialization of the specifications of the corrosion-resistant insulating sleeves 3. By selecting combinations of corrosion-resistant insulating sleeves 3 with different inner diameters, flow channel structures with different stepped levels can be formed. In practical applications, corrosion-resistant insulating sleeves 3 with corresponding stepped level combinations can be selectively installed according to the required flow distribution characteristics. Figure 3 (a) Figure 3 (b) Figure 3 (c) Schematic illustration of three corrosion-resistant insulating sleeves with different inner diameters 3.

[0033] Both the liquid inlet 11 and the corrosion-resistant insulating sleeve 3 are flat. Figure 4A schematic diagram of the corrosion-resistant insulating sleeve 3 axially extending through the opening 31 is shown. The shape shown is equivalent to the cross-section of the corrosion-resistant insulating sleeve 3, and the shaded area represents the region where the opening 31 is located. In practical applications, the inner diameter of the corrosion-resistant insulating sleeve 3 in each stepped region of the alkali channel 100 can be controlled with reference to the following:

[0034] In the above, k represents the current step number, which is counted sequentially along the direction of alkali flow. (Reference) Figure 4 As shown, L0 is the characteristic length of the inlet 11 cross-section, in mm, and R0 is the characteristic radius of the inlet 11 cross-section, in mm. k R is the characteristic length of the corrosion-resistant insulating bushing section 3 within the current stepped area, in mm. k S0 is the characteristic radius inside the cross-section of the corrosion-resistant insulating sleeve 3 within the current stepped region, in mm. S0 is the cross-sectional area of ​​the inlet 11, in mm2. 2 S k This is the cross-sectional area of ​​the corrosion-resistant insulating sleeve 3 within the current step region (excluding the shaded area where the opening 31 is located), in mm. 2 .

[0035] Each of the adjacent gaskets 2 of the bipolar plate 1 has a channel opening 21 corresponding to the position of the liquid inlet 11 and the gas-liquid outlet 12. A corrosion-resistant insulating sleeve 3 is inserted into the liquid inlet 11 and the gas-liquid outlet 12 of a single bipolar plate 1, and also into the channel opening 21 of a gasket 2 axially adjacent to the bipolar plate 1. Two adjacent bipolar plates 1 and the gasket 2 between the two bipolar plates 1 combine to form an electrolysis chamber. More preferably, a convex plate 33 is provided at one end of the corrosion-resistant insulating sleeve 3, and a positioning groove 22 is provided at the edge of the channel opening 21 of the gasket 2. The depth of the positioning groove 22 is the same as the thickness of the convex plate 33, specifically 1~2mm, and the shape of the positioning groove 22 is the same as the shape of the convex plate 33. Based on this setup, the installation of the corrosion-resistant insulating sleeve 3 can be positioned. Compared to using tools to assist in positioning the corrosion-resistant insulating sleeve 3, the positioning using the protruding plate 33 and the positioning groove 22 is convenient and cost-effective. After all the bipolar plates 1 and gaskets 2 are stacked and assembled, the cooperation between the protruding plate 33 and the positioning groove 22 forms an axial limiting structure for the corrosion-resistant insulating sleeve 3, effectively restricting its axial position. Furthermore, the positioning groove 22 is located on the gasket 2 without damaging the original structure of the bipolar plate 1.

[0036] Preferably, the convex plate 33 is located on both sides of one end of the corrosion-resistant insulating sleeve 3 to achieve symmetrical positioning and effectively prevent the corrosion-resistant insulating sleeve 3 from being installed skewed.

[0037] like Figure 7As shown, δ s The depth of the liquid inlet 11 or the gas-liquid inlet 12 is the thickness of the bipolar plate 1 frame in the Y direction, δ. d The depth of channel opening 21 is the thickness of gasket 2 in the Y direction, δ. t δ represents the axial dimension of the corrosion-resistant insulating sleeve 3, which is its dimension in the Y direction. In this utility model: δ t =δ s +δ d .

[0038] Since the gas-liquid channel 200 does not concern itself with flow diversion, all corrosion-resistant insulating sleeves 3 within the gas-liquid channel 200 are of the same specification, with a thickness of 2~5mm. Their main function is to mitigate metal corrosion and reduce the proportion of stray current. (Shape reference...) Figure 3 (a).

[0039] Figure 1 The flow direction of the example structure is from both ends to the middle, and the number of steps can be selected as 2 to 5. Figure 8 The flow direction of the example structure is from one end to the other, and the number of steps can be selected from 3 to 10.

[0040] With the alkaline electrolytic cell flow direction as Figure 1 Taking the example structure as an example, a comparison is made with and without the corrosion-resistant insulating sleeve 3. The corrosion-resistant insulating sleeve 3 adopts a structure with an opening 31 running through it, and the number of steps is 3. The flow uniformity coefficient can be used... Calculate, where Q i Let i be the flow rate of the i-th chamber. This is the average flow rate of all chambers; the closer the value is to 1, the more uniform the flow rate. (See comparison results for reference.) Figure 5 As shown, the flow uniformity coefficient of the alkaline electrolytic cell without the corrosion-resistant insulating sleeve 3 is approximately 0.641, while the flow uniformity coefficient of the alkaline electrolytic cell with the corrosion-resistant insulating sleeve 3 is approximately 0.875, representing a 37% improvement in flow uniformity. Current density: 2600 A / m³ 2 Example of a comparative structure reference Figure 6 As shown, the current efficiency of the alkaline electrolytic cell without the corrosion-resistant insulating sleeve 3 is about 93.6%, while the current efficiency of the alkaline electrolytic cell with the corrosion-resistant insulating sleeve 3 is about 96.3%, representing an increase of 2.7%.

[0041] This invention also provides an alkaline electrolytic cell with the flow channel structure described above. This structure minimizes or isolates direct contact between the alkaline solution and the metal channel during flow, effectively mitigating metal corrosion in the "alkaline solution-two-phase flow impact-strong oxidizing" environment and extending the service life of the alkaline electrolytic cell. It significantly reduces stray current conduction to the bipolar plate 1 metal frame, improving the current efficiency of the alkaline electrolytic cell, and optimizes the alkaline solution flow distribution in each electrolysis chamber, improving flow distribution uniformity and temperature uniformity, and reducing energy consumption.

[0042] 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.

[0043] 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 flow channel structure of an alkaline electrolyzer, characterized by, It includes an alkali channel (100) and a gas-liquid channel (200). Both the alkali channel (100) and the gas-liquid channel (200) are provided with corrosion-resistant insulating sleeves (3). The corrosion-resistant insulating sleeves (3) form a flow channel for the flow of alkali or gas and liquid. The corrosion-resistant insulating sleeves (3) have openings (31) on their sides so that the interior of the corrosion-resistant insulating sleeves (3) is connected to the electrolysis chamber. The inner diameter of the flow channel formed inside the corrosion-resistant insulating sleeves (3) in the alkali channel (100) gradually decreases along the direction of alkali flow.

2. The flow channel structure of an alkaline electrolyzer according to claim 1, wherein The corrosion-resistant insulating sleeve (3) set in the alkali channel (100) has an inner diameter of the flow channel that gradually decreases in a stepped manner along the direction of alkali flow, and the inner diameter of the flow channel in a single stepped area is the same.

3. The flow channel structure of the alkaline electrolytic cell as described in claim 1, characterized in that, The opening (31) axially extends through both ends of the corrosion-resistant insulating sleeve (3).

4. The flow channel structure of the alkaline electrolytic cell as described in claim 3, characterized in that, The two sides of the opening (31) are connected to the inner wall of the corrosion-resistant insulating sleeve (3) by tie rods (32).

5. The flow channel structure of an alkaline electrolyzer according to claim 4, wherein The connection between the corrosion-resistant insulating sleeve (3) and the tie rod (32) is located in the area opposite to the opening (31) on the inner wall of the corrosion-resistant insulating sleeve (3).

6. The flow channel structure of the alkaline electrolyzer according to any one of claims 1-5, characterized in that, The alkali channel (100) consists of inlets (11) on all bipolar plates (1), and the gas-liquid channel (200) consists of gas-liquid outlets (12) on all bipolar plates (1). A corrosion-resistant insulating sleeve (3) is inserted into each inlet (11) and gas-liquid outlet (12) of a single bipolar plate (1). The corrosion-resistant insulating sleeves (3) inside the inlets (11) of all bipolar plates (1) together form a flow channel for alkali flow, and the corrosion-resistant insulating sleeves (3) inside the gas-liquid outlets (12) of all bipolar plates (1) together form a flow channel for gas-liquid flow.

7. The flow channel structure of the alkaline electrolytic cell as described in claim 6, characterized in that, Each of the adjacent gaskets (2) of the bipolar plate (1) is provided with a channel (21) corresponding to the position of the liquid inlet (11) and the gas-liquid inlet (12). A corrosion-resistant insulating sleeve (3) is installed in the liquid inlet (11) and the gas-liquid inlet (12) of a single bipolar plate (1), and is also installed in the channel (21) of a gasket (2) that is axially adjacent to the bipolar plate (1).

8. The flow channel structure of the alkaline electrolytic cell as described in claim 7, characterized in that, One end of the corrosion-resistant insulating sleeve (3) is provided with a convex plate (33), and the gasket (2) is provided with a positioning groove (22) at the edge of the channel opening (21). The depth of the positioning groove (22) is the same as the thickness of the convex plate (33), and the shape of the positioning groove (22) is the same as the shape of the convex plate (33).

9. The flow channel structure of the alkaline electrolytic cell as described in claim 8, characterized in that, The protruding plate (33) is located on both sides of one end of the corrosion-resistant insulating sleeve (3).

10. An alkaline electrolyzer characterized by, The flow channel structure of the alkaline electrolyzer as described in any one of claims 1-9 is provided.

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