Water electrolyser structure for promoting bubble removal

Abstract

The invention discloses a water electrolyser structure for promoting bubble removal, and relates to the technical field of water electrolysers, the water electrolyser structure comprises a plurality of stacked subunits, and each subunit comprises a main pole plate and an insulation sealing gasket; liquid inlets are formed in the main polar plate and the insulating sealing gasket, an electrolyte distribution cavity used for storing electrolyte is formed in the main polar plate, a first flow channel is formed in the liquid inlet and an inner cavity of the main polar plate, and first air outlets and second air outlets are formed in the main polar plate and the insulating sealing gasket; the first air outlet, the second air outlet and the inner cavity of the main polar plate form a second flow channel and a third flow channel respectively, and a third air outlet and a fourth air outlet are formed in the reverse side of the main polar plate. The water electrolysis device has the effects of improving the water electrolysis efficiency and reducing bubble aggregation.

Description

Technical Field

[0001] The present application relates to the technical field of water electrolysis cells, and in particular to a water electrolysis cell structure that promotes the removal of bubbles. Background Art

[0002] Water electrolyzer hydrogen production technology is a key link in the energy conversion and storage steps. Large-scale hydrogen production can be achieved through water electrolyzers, but at high current density, the large-scale formation and retention of bubbles have a great impact on the optimal performance of water electrolyzers. On the other hand, the large-scale electrolyzer will inevitably lead to an increase in electrolytic chambers, and the increase in chambers will inevitably cause the gas flow path to become longer, and the gas flow resistance of each chamber is different, resulting in uneven voltage in each chamber. Therefore, it is necessary to carry out refined design of the electrolyzer gas flow channel to reduce resistance, speed up the rapid transmission of gas, and ensure the stable operation of the electrolyzer.

[0003] By changing the pore size of the diffusion layer, the electrolyte flow rate and other methods, it is possible to prevent microbubbles (30-120 microns) from forming a non-conductive layer on the electrode surface under high current density. However, a large number of bubbles cannot quickly enter the manifold or the gas / liquid mixture in the manifold cannot be efficiently removed, which will lead to a reduction in the effective area of ​​the electrolytic cell.

[0004] Increasing the size of the manifold can effectively increase the amount of gas / liquid mixture removed, but the cost needs to be increased accordingly. Based on this, how to accelerate the gas discharge in the electrolyzer under high current density and prevent bubble aggregation from reducing the performance of the electrolyzer has practical significance in the industrial application of electrolyzers. Summary of the invention

[0005] In order to improve the problem of preventing bubbles from agglomerating and reducing the performance of the electrolytic cell when discharging gas in the electrolytic cell, the present application provides a water electrolytic cell structure that promotes the removal of bubbles.

[0006] The present application provides a water electrolysis cell structure that promotes bubble removal, which adopts the following technical solution: A water electrolyzer structure for promoting bubble removal comprises a plurality of stacked subunits, each of the subunits comprises a main pole plate and an insulating sealing gasket; the main pole plate and the insulating sealing gasket are both provided with a liquid inlet, the main pole plate is provided with an inner cavity for storing electrolyte, the liquid inlet and the inner cavity of the main pole plate form a No. 1 flow channel, the main pole plate and the insulating sealing gasket are both provided with a No. 1 gas outlet and a No. 2 gas outlet, the No. 1 gas outlet, the No. 2 gas outlet and the inner cavity of the main pole plate form a No. 2 flow channel and a No. 3 flow channel respectively, and the back of the main pole plate is provided with a No. 3 gas outlet and a No. 4 gas outlet.

[0007] By adopting the above technical scheme, several sub-unit bodies are stacked into one, and the liquid inlets are interconnected to form an electrolyte channel. After the electrolyte enters the channel, it enters the inner cavity of the main electrode plate through the No. 1 flow channel of each sub-unit, enters the No. 1 gas outlet and the No. 2 gas outlet through the No. 2 flow channel and the No. 3 flow channel, and finally flows out of the tank body to form a liquid inlet and multiple flow channels, so that the electrolyte can smoothly enter the inner cavity for electrochemical reaction, and the generated gas / liquid mixture is quickly discharged through the No. 2 flow channel and the No. 3 flow channel, thereby improving the gas removal efficiency and ensuring the stable operation of the electrolytic cell.

[0008] Optionally, the apertures of the first gas outlet, the second gas outlet, the third gas outlet and the fourth gas outlet gradually change along the stacking direction of the electrolytic cells to form a gradient structure.

[0009] By adopting the above technical scheme, different gas / liquid mixture flow rates are formed in the electrolytic cell, which significantly improves the bubble removal efficiency and ensures the uniformity of the gas / liquid mixture removal rate in each small chamber of the electrolytic cell, thereby improving the overall performance and stability of the electrolytic cell.

[0010] Optionally, the apertures of the No. 1 and No. 4 gas outlets increase along the stacking direction of the electrolytic cells, and the apertures of the No. 2 and No. 3 gas outlets decrease along the stacking direction of the electrolytic cells; the No. 1 and No. 4 gas outlets and the No. 2 and No. 3 gas outlets are opposite along the stacking direction of the electrolytic cells.

[0011] By adopting the above technical solution, according to Bernoulli's principle, the flow rate of the gas / liquid mixture at the No. 1 gas outlet of the electrolytic cell is gradually accelerated along the sub-unit stacking direction, until the gas / liquid mixture of the last sub-unit enters the No. 2 flow channel to the electrolyte distribution chamber along the No. 1 gas outlet, and then enters the No. 2 gas outlet along the No. 3 flow channel and is discharged out of the cell in the opposite direction of the electrolytic cell stacking.

[0012] Optionally, the cross-sectional shapes of the air outlet No. 1, the air outlet No. 2, the air outlet No. 3 and the air outlet No. 4 are any one of circular, square and waist-shaped.

[0013] By adopting the above technical solution, the cross-sections of multiple gas outlets are diversified, so as to better adapt to different application scenarios and needs, optimize the flow path of the gas / liquid mixture, and further improve the gas emission efficiency.

[0014] Optionally, the first air outlet and the fourth air outlet enter the second air outlet and the third air outlet through the last small chamber in the stacking direction, and the rotating structure accelerates the gas / liquid mixture to pass through the second flow channel and the third flow channel.

[0015] By adopting the above technical solution, the removal rate of the gas / liquid mixture is increased, the gas removal efficiency of the water electrolyzer is further improved, and the influence of bubble aggregation on the electrolysis performance in the water electrolyzer is reduced.

[0016] Optionally, the aperture gradient of the first air outlet varies from 10 to 20 mm.

[0017] By adopting the above technical solution, the pore size gradient changes to 10~20 mm, making the gas / liquid mixture removal rate more uniform in each small chamber, effectively improving the problem of uneven gas removal in the electrolytic cell, improving the bubble removal efficiency, and reducing the impact of bubble aggregation on electrolytic performance.

[0018] Optionally, the main pole plate and the insulating sealing gasket in each subunit have the same aperture.

[0019] By adopting the above technical solution, the insulating sealing gasket has a liquid inlet, a No. 1 gas outlet and a No. 2 gas outlet with the same aperture as the main electrode plate, ensuring that the flow path of the electrolyte and the gas / liquid mixture in each sub-unit is consistent, which helps to maintain the uniformity of the internal flow characteristics of the entire water electrolyzer structure, thereby improving the stability and efficiency of the electrolyzer operation.

[0020] Optionally, the center of the first air outlet is lower than the center of the second air outlet.

[0021] By adopting the above technical solution, the gas / liquid mixture can be more easily gathered and discharged at the No. 1 outlet, reducing the residence time of bubbles in the inner cavity of the main electrode plate, thereby improving the bubble removal efficiency and further improving the overall performance of the electrolytic cell.

[0022] In summary, the present application includes at least one of the following beneficial technical effects: 1. It can increase the rate at which the gas / liquid mixture in the inner cavity of the main plate passes through the No. 2 and No. 3 flow channels, and can increase the flow rate of the gas / liquid mixture in the No. 1 and No. 4 gas outlets, and can discharge more gas in the same time; 2. By changing the aperture gradually, the gas removal rate of each chamber along the No. 2 and No. 3 flow channels is made more uniform, thus improving the uneven voltage phenomenon of each chamber of the electrolytic cell; 3. The structural design that the center of the No. 1 gas outlet is lower than the center of the No. 2 gas outlet allows the gas / liquid mixture to pass through the No. 1 gas outlet first, thereby accelerating the removal rate of the gas / liquid mixture and improving the uniformity of gas removal at each hour. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1This application shows a schematic diagram of the flow direction of the gas / liquid mixture in the electrolytic cell along the sub-unit stacking direction.

[0025] Figure 2 These are the polarization curves of the electrolytic cell tests with and without the gradient structure.

[0026] Figure markings: 1. Air outlet No. 1; 2. Air outlet No. 2; 3. Air outlet No. 3; 4. Air outlet No. 4; 5. Flow channel No. 2; 6. Flow channel No. 3; 7. Liquid inlet; 8. Flow channel No. 1; 9. Electrolyte distribution chamber. DETAILED DESCRIPTION

[0027] The following is combined with Figure 1 This application is described in further detail.

[0028] The embodiment of the present application discloses a water electrolysis cell structure that promotes the removal of bubbles.

[0029] Reference Figure 1 , including a plurality of stacked subunits with gradient structures. The front of the main plate in each subunit includes a liquid inlet 7 and a No. 1 flow channel 8 for the electrolyte to enter the electrolyte distribution chamber 9. Each subunit includes a main plate and an insulating sealing gasket that is resistant to alkali corrosion and has a certain strength. The back of the main plate is provided with a No. 3 gas outlet and a No. 4 gas outlet. The insulating sealing gasket has a liquid inlet 7, a No. 1 gas outlet 1, a No. 2 gas outlet 2, a No. 3 gas outlet 3 and a No. 4 gas outlet 4 with the same aperture as the main plate, which ensures that the flow path of the electrolyte and the gas / liquid mixture in each subunit is consistent, which helps to maintain the uniformity of the internal flow characteristics of the entire water electrolyzer structure, thereby improving the stability and efficiency of the electrolyzer operation.

[0030] The first gas outlet 1 and the fourth gas outlet 4 enter the second gas outlet 2 and the third gas outlet 3 through the last small chamber in the stacking direction. The rotary structure accelerates the gas / liquid mixture through the second flow channel 5 and the third flow channel 6, improves the removal rate of the gas / liquid mixture, further improves the gas removal efficiency of the water electrolyzer, and reduces the influence of bubble aggregation on the electrolysis performance in the water electrolyzer. The gas / liquid mixture after the electrochemical reaction in the electrolyte distribution chamber 9 passes through the second flow channel 5 and the third flow channel 6 and enters the first gas outlet 1 and the second gas outlet 2. The structure of the back side of the main plate is similar to that of the front side, and the gas / liquid mixture enters the third gas outlet 3 and the fourth gas outlet 4 through the flow channel.

[0031] The electrolyte passes through the main plate through the liquid inlet 7, and the electrolyte in the liquid inlet 7 enters the electrolyte distribution chamber 9 through the No. 1 flow channel 8. The electrolyte in the electrolyte distribution chamber 9 is decomposed into oxygen under the action of voltage. The oxygen / electrolyte mixture enters the No. 1 gas outlet 1 and the No. 2 gas outlet 2 along the No. 2 flow channel 5 and the No. 3 flow channel 6. The gas-liquid mixture passing through the No. 1 gas outlet 1 moves along the stacking direction of the electrolytic cell sub-units, and the aperture of the No. 1 gas outlet 1 of each sub-unit becomes smaller in proportion; the gas-liquid mixture passing through the No. 2 gas outlet 2 is directly discharged from the electrolytic cell.

[0032] The apertures of gas outlet No. 1 and gas outlet No. 4 increase along the stacking direction of the electrolytic cells, while the apertures of gas outlet No. 2 and gas outlet No. 3 decrease along the stacking direction of the electrolytic cells. Gas outlet No. 1 and gas outlet No. 4 and gas outlet No. 2 and gas outlet No. 3 are opposite along the stacking direction of the electrolytic cells. According to Bernoulli's principle, the flow rate of the gas / liquid mixture at gas outlet No. 1 of the electrolytic cell gradually increases along the sub-unit stacking direction, and finally the gas-liquid mixture of the sub-unit enters the No. 2 flow channel 5 to the electrolyte distribution chamber 9 along the No. 1 gas outlet 1, and then enters the No. 2 gas outlet 2 along the No. 3 flow channel 6 and is discharged out of the cell in the opposite direction of the electrolytic cell stacking.

[0033] The change in the aperture of the electrolytic cell gas outlet 1 along the stacking direction causes the gas / liquid mixture to flow faster. According to the Venturi effect, the rate gradient of the gas / liquid mixture in the electrolyte distribution chamber 9 through the No. 2 flow channel 5 will change, and increase along the stacking direction of the electrolytic cell. When the gas output is large, the gas content in each unit distribution chamber 9 is different. Among them, the gas content of the first unit is the largest, and the gas content of the last unit is the smallest, which ultimately affects the uniform distribution of the voltage of each unit. In order to solve the above-mentioned uneven voltage distribution of each unit, a No. 2 gas outlet 2 is set, and its aperture size decreases along the stacking direction of the electrolytic cell, which can effectively alleviate the uneven voltage caused by the aperture change of the No. 1 gas outlet 1. Among them, the gas / liquid mixture of the last unit No. 1 gas outlet 1 is set to enter the electrolyte distribution chamber 9 along the No. 2 flow channel 5, and then enter the No. 2 gas outlet 2 along the No. 3 flow channel 6. Not only can the removal rate of the gas / liquid mixture at the No. 2 gas outlet 2 be increased, but also the temperature of each unit of the electrolytic cell can be evenly distributed.

[0034] The center of the No. 1 gas outlet hole 1 is lower than the center of the No. 2 gas outlet hole 2, which can make the gas / liquid mixture easier to gather and discharge at the No. 1 gas outlet, reduce the residence time of bubbles in the inner cavity of the main electrode plate, thereby improving the bubble removal efficiency and further improving the overall performance of the electrolytic cell. The gas / liquid mixture preferentially passes through the No. 1 gas outlet, thereby accelerating the removal rate of the gas / liquid mixture and improving the uniformity of gas removal in each small chamber.

[0035] The front of the main plate with gradient structure undergoes oxygen evolution reaction, which is used for oxygen production; the back of the main plate is used for hydrogen evolution reaction, which also has a similar gradient structure. Similar to the above scheme, the fourth outlet hole 4 is set to preferentially pass the gas-liquid mixture, and the aperture increases along the stacking direction of the electrolytic cells; the aperture of the third outlet hole 3 decreases along the stacking direction of the electrolytic cells, which is used to balance the uneven distribution of the cell voltage caused by the fourth outlet hole 4.

[0036] The cross-sectional shapes of gas outlet No. 1, gas outlet No. 2, gas outlet No. 3 and gas outlet No. 4 can be circular, square or waist-shaped. The diversified cross-sectional shapes can be suitable for different application scenarios and needs, optimize the flow path of the gas / liquid mixture, and improve the efficiency of gas emission. In this embodiment, any gas outlet is circular, and the aperture gradient range is 10~20 mm. The gas / liquid mixture removal rate is more uniform in each small chamber, which effectively improves the problem of uneven gas removal in the electrolytic cell, improves the bubble removal efficiency, and reduces the influence of bubble aggregation on the electrolytic performance.

[0037] Figure 2 The performance test comparison of the electrolyzer with gradient structure and the electrolyzer without gradient structure. The test electrolyte is 30%wt KOH solution at 80℃, and the test current density range is 200-12000 A m -2 When the current density is less than 5000A m -2 When the current density is greater than 5000A m -2 The electrolytic cell containing the gradient structure has a lower electrolysis voltage, and the improvement effect becomes more obvious as the current density increases.

[0038] The implementation principle of a water electrolyzer structure for promoting bubble removal in the embodiment of the present application is: based on the Bernoulli principle and the Venturi effect, a gradient aperture bipolar plate stacked electrolyzer structure is designed. The accelerated removal of the gas / liquid mixture in each cell of the electrolyzer is achieved, and at the same time, the problem of different gas / liquid mixture removal rates in each cell caused by the excessive length of the cell body of a large water electrolyzer is solved, and the phenomenon of uneven voltage in each cell of the electrolyzer is improved.

[0039] Unless otherwise defined, the technical terms or scientific terms used in this application should be understood by people with ordinary skills in the field to which this application belongs. The words "first", "second", "third" and similar words used in the specification and claims of this application do not indicate any order, quantity or importance, but are only used to distinguish different components. "One" or "one" and similar words do not indicate a quantitative limit, but indicate that there is at least one. "Include" or "comprise" and similar words mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0040] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A water electrolysis cell structure for promoting bubble removal, characterized in that: The invention comprises a plurality of stacked sub-units, each of which comprises a main pole plate and an insulating sealing gasket; the main pole plate and the insulating sealing gasket are both provided with a liquid inlet (7); the main pole plate is provided with an electrolyte distribution cavity (9) for storing electrolyte; the liquid inlet (7) and the inner cavity of the main pole plate form a first flow channel (8); the main pole plate and the insulating sealing gasket are both provided with a first gas outlet (1) and a second gas outlet (2); the first gas outlet (1), the second gas outlet (2) and the inner cavity of the main pole plate respectively form a second flow channel (5) and a third flow channel (6); the back of the main pole plate is provided with a third gas outlet (3) and a fourth gas outlet (4).

2. A water electrolysis cell structure for promoting bubble removal according to claim 1, characterized in that: The apertures of the first gas outlet (1), the second gas outlet (2), the third gas outlet (3) and the fourth gas outlet (4) gradually change along the stacking direction of the electrolytic cells, forming a gradient structure.

3. A water electrolysis cell structure for promoting bubble removal according to claim 2, characterized in that: The apertures of the No. 1 gas outlet (1) and the No. 4 gas outlet (4) increase along the stacking direction of the electrolytic cells, while the apertures of the No. 2 gas outlet (2) and the No. 3 gas outlet (3) decrease along the stacking direction of the electrolytic cells; the No. 1 gas outlet (1), the No. 4 gas outlet (4) and the No. 2 gas outlet (2), the No. 3 gas outlet (3) are opposite along the stacking direction of the electrolytic cells.

4. A water electrolysis cell structure for promoting bubble removal according to claim 3, characterized in that: The cross-sectional shapes of the first air outlet (1), the second air outlet (2), the third air outlet (3) and the fourth air outlet (4) are any one of circular, square and waist-shaped.

5. A water electrolysis cell structure for promoting bubble removal according to claim 4, characterized in that: The first air outlet and the fourth air outlet enter the second air outlet and the third air outlet through the last small chamber in the stacking direction, and the rotating structure accelerates the gas / liquid mixture to pass through the second flow channel (5) and the third flow channel (6).

6. A water electrolysis cell structure for promoting bubble removal according to claim 4, characterized in that: The aperture gradient of the first air outlet (1) varies from 10 to 20 mm.

7. A water electrolysis cell structure for promoting bubble removal according to claim 1, characterized in that: The main pole plate and the insulating sealing gasket in each subunit have the same aperture.

8. A water electrolysis cell structure for promoting bubble removal according to claim 1, characterized in that: The center of the first air outlet (1) is lower than the center of the second air outlet (2).

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