Electrolytic cell and alkaline electrolyzer

Abstract

This invention belongs to the field of water electrolysis for hydrogen production technology, specifically relating to an electrolysis chamber and an alkaline electrolyzer. The chamber includes two bipolar plates, a cathode support structure, a cathode electrode, a diaphragm, a cathode electrode, and an anode support structure, all of which are elliptical in shape, with the major axis of the ellipse aligned along the height of the electrolysis chamber. A first flexible support structure is located in the lower region of the electrolysis chamber, and a first rigid support structure is located in the upper region. A second rigid support structure is located in the lower region of the electrolysis chamber, and a second flexible support structure is located in the upper region. This invention effectively suppresses temperature-pressure coupling failure of the electrolysis chamber support structure, achieves zero-distance between the electrode and the diaphragm, improves the overall stability and load-bearing capacity of the cathode and anode support structures, avoids increased contact resistance and uneven current density caused by uneven support, improves the uniformity of current distribution during long-term operation, and enhances current efficiency and overall operational stability of the alkaline electrolyzer.

Description

Technical Field

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

[0002] Alkaline water electrolysis for hydrogen production has become a preferred technology for large-scale hydrogen production due to its advantages such as low cost, stable operation, and long lifespan, attracting significant market attention. An alkaline electrolyzer typically consists of multiple electrolysis cells connected in series. Each electrolysis cell mainly comprises bipolar plates, electrodes, diaphragms, gaskets, and supporting structures.

[0003] Furthermore, to achieve a "zero-gap" design between the electrodes and the diaphragm, existing electrolytic cells typically employ elastic support structures. Most existing electrolysis chambers are circular, and the waist regions on both sides are prone to forming flow dead zones, resulting in poor electrolyte mass transfer and an inability to replenish electrolyte and dissipate heat in a timely manner, thus creating high-temperature dried-out areas. These high-temperature dried-out areas not only threaten the safety of the internal structure of the electrolytic cell but also significantly accelerate the high-temperature creep aging of the elastic support structure, thereby accelerating its failure. Taking a two-month alkali boiling test of an elastic support structure (0.19mm diameter elastic mesh) as an example, the equivalent deformation modulus decreases by approximately 4%~8% at 80℃, while at 95℃, the equivalent deformation modulus decreases by 18%~26%, indicating that increasing temperature exponentially increases the creep rate. Furthermore, in alkaline water electrolysis, differences exist in gas production, gas production rate, and bubble size between the cathode and anode. Coupled with fluctuations in electrolysis load and frequent start-ups and shutdowns, this leads to significant gas-liquid two-phase flow disturbances. These disturbances generate high-frequency alternating pulsating forces at the 10-100 Pa level on both sides of the diaphragm, acting axially and perpendicularly on the elastic support structure. Long-term high-frequency vibration causes accumulated plastic deformation, decreased resilience, and misalignment friction, ultimately resulting in elastic collapse, localized creep aging, and accelerated fatigue failure of the elastic support structure.

[0004] Failure of the elastic support structure will cause the contact between the electrodes and bipolar plates to become loose or unstable, which will not only lead to problems such as increased contact resistance and uneven current distribution, affecting current efficiency, but also reduce the overall stability of the electrolytic cell and cause safety hazards. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an electrolytic cell and alkaline electrolytic cell that effectively suppresses the temperature-pressure coupling failure of the electrolytic cell support structure, improves the overall stability and load-bearing capacity of the cathode support structure and anode support structure on the basis of achieving zero gap between the electrode and the diaphragm, avoids problems such as increased contact resistance and uneven current density caused by uneven support, improves the uniformity of current distribution under long-term operation, improves current efficiency and the overall operational stability of the alkaline electrolytic cell.

[0006] The present invention provides an electrolysis chamber, including two bipolar plates, and further including a cathode support structure, a cathode electrode, a diaphragm, a cathode electrode, and an anode support structure stacked sequentially between the two bipolar plates along the axial direction of the electrolysis chamber. The two bipolar plates, the cathode support structure, the cathode electrode, the diaphragm, the cathode electrode, and the anode support structure are all elliptical, and the major axis of the ellipse is arranged along the height direction of the electrolysis chamber. The cathode support structure includes a first flexible support structure and a first rigid support structure arranged in a spliced ​​configuration. The first flexible support structure is located in the lower region of the electrolysis chamber, and the first rigid support structure is located in the upper region of the electrolysis chamber. The anode support structure includes a second rigid support structure and a second flexible support structure arranged in a spliced ​​configuration. The second rigid support structure is located in the lower region of the electrolysis chamber, and the outer contours of the second rigid support structure and the first flexible support structure coincide in the axial projection view of the electrolysis chamber. The second flexible support structure is located in the upper region of the electrolysis chamber, and the outer contours of the second flexible support structure and the first rigid support structure coincide in the axial projection view of the electrolysis chamber.

[0007] Furthermore, the minor axis dimensions of the bipolar plate, cathode support structure, cathode electrode, diaphragm, anode electrode, and anode support structure are all 0.5 to 0.9 times their major axis dimensions.

[0008] Furthermore, the joint boundary between the first flexible support structure and the first rigid support structure is a straight line.

[0009] Furthermore, the splicing boundary is a straight line parallel to the short axis of the electrolysis chamber, and the height parameter of the splicing boundary on the long axis of the electrolysis chamber is obtained by selecting the gas content characteristic value after obtaining the gas content contour curve of the hydrogen side of the electrolysis chamber through simulation.

[0010] Furthermore, the method for obtaining the height parameter of the splicing boundary on the long axis of the electrolysis chamber includes the following steps: S1. Set the basic parameters of the electrolysis chamber and the alkaline electrolysis cell to be used, including the rated current density and geometric dimensions; S2. Based on the basic parameters described in S1, establish a three-dimensional geometric model of the electrolysis chamber and the alkaline electrolysis cell to be used. According to the geometric characteristics inside the electrolysis chamber, construct a multi-physics numerical model. Through simulation of the multi-physics numerical model, obtain the distribution curve of the gas content on the hydrogen side inside the electrolysis chamber. S3. In the gas content contour curve distribution map obtained in S2, select a gas content feature value, and use image tools to perform grayscale recognition on the area below the curve containing the gas content feature value in the gas content contour curve distribution map. Generate uniformly distributed random points in the gas content contour curve distribution map, count the number of points falling into the grayscale recognition area, and calculate the area of ​​the grayscale recognition area. S 灰 ; The desired splicing boundary height parameter inside the electrolysis chamber is set as follows: y 界限 Then set the electrolysis chamber to be located inside y 界限 Planar area of ​​the lower region S 下 = S 灰 ,pass S 灰 Calculated y 界限 The value of is obtained to obtain the height parameter of the splicing boundary on the long axis of the electrolysis chamber.

[0011] Furthermore, the uncompressed free height of the first flexible support structure in the axial direction of the electrolysis chamber and the height of the first rigid support structure in the axial direction of the electrolysis chamber, as well as the uncompressed free height of the second flexible support structure in the axial direction of the electrolysis chamber and the height of the second rigid support structure in the axial direction of the electrolysis chamber, all satisfy a proportional relationship: Furthermore, the height of the first flexible support structure after compression between the cathode electrode and its corresponding bipolar plate cathode surface is the same as the height of the first rigid support structure in the axial direction of the electrolysis chamber, and the height of the second flexible support structure after compression between the cathode electrode and its corresponding bipolar plate anode surface is the same as the height of the second rigid support structure in the axial direction of the electrolysis chamber.

[0012] Furthermore, the first flexible support structure and the second flexible support structure are elastic nets, which are woven together by interlacing transverse and longitudinal metal wires, and at least one of the transverse and longitudinal metal wires is wavy, so that the elastic net as a whole has a W-shaped waveform.

[0013] Furthermore, the first rigid support structure and the second rigid support structure are plate mesh or nipple plates.

[0014] Furthermore, the thickness of the hydrogen-side region formed between the cathode and its corresponding bipolar cathode surface in the axial direction of the electrolysis chamber is [missing information]. The thickness of the oxygen-side region formed between the anode and its corresponding bipolar plate anode surface in the axial direction of the electrolysis chamber is [missing information]. The and The relationship is: .

[0015] The present invention also provides an alkaline electrolytic cell, including two end plates and several electrolytic cells as described above. The several electrolytic cells are stacked sequentially between the two end plates along the axial direction of the alkaline electrolytic cell, and two adjacent electrolytic cells along the axial direction of the alkaline electrolytic cell share a bipolar plate.

[0016] The beneficial effects of this invention are that the electrolysis chamber is elliptical in shape with its major axis along its height, which shortens the flow path of the alkali solution along both sides, optimizes the gas-liquid distribution of the alkali solution between the electrodes, and forms a smoother flow path inside the electrolysis chamber. This allows the heat generated on the electrode surfaces in the areas on both sides of the electrolysis chamber to be carried away in a timely manner, thereby eliminating the flow dead zone at the waist position on both sides of the traditional circular electrolysis chamber, avoiding the problem of high-temperature drying, reducing the risk of high-temperature creep aging of the flexible support structure, simplifying the arrangement of the flow channels on the surface of the main electrode plate of the bipolar plate, reducing the processing difficulty and cost, and at the same time, the elliptical structure has no sharp corner stress singularities, resulting in higher pressure resistance. The alkaline electrolysis cell composed of electrolysis chambers with this elliptical structure has higher overall structural stability during operation, which helps to reduce safety hazards.

[0017] The cathode and anode support structures together form a reverse symmetrical splicing support structure inside the electrolysis chamber, with a soft bottom and a hard top in the hydrogen side region and a hard bottom and a soft top in the oxygen side region. This not only matches the electrochemical reaction characteristics of the upper and lower parts of the hydrogen and oxygen sides, but also forms a more symmetrical mechanical constraint system. The cathode and anode support structures complement each other in terms of soft / hard stiffness. The deformation freedom of the flexible support structure is reversed and limited by the rigid support structure on the opposite side, which constrains the unidirectional tensile and collapse displacement of the flexible support structure. This alleviates the eccentric deformation and local compression deformation under the pressure difference fluctuation of the gas-liquid two-phase flow, and counteracts the support deformation vibration caused by the pressure difference pulsation of the gas-liquid two-phase flow. It significantly weakens the reciprocating deformation and high-frequency vibration of the flexible support structure, and delays the fatigue failure and aging rate of the flexible support structure.

[0018] Based on the synergistic effect of the elliptical structure and the reverse symmetrical splicing support structure, the temperature-pressure coupling failure of the electrolysis chamber support structure is effectively suppressed. On the basis of achieving zero gap between the electrode and the diaphragm, the overall stability and load-bearing capacity of the cathode support structure and the anode support structure are improved, thereby improving the support uniformity under long-term operation, avoiding problems such as increased contact resistance and uneven current density caused by uneven support, improving the current distribution uniformity under long-term operation, improving current efficiency and the overall operational stability of the alkaline electrolyzer, and reducing safety hazards caused by operational instability. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the electrolysis chamber decomposition of the present invention.

[0020] Figure 2 This is a schematic diagram of the bipolar plate contour coordinates of the present invention.

[0021] Figure 3 This is a schematic diagram of the bipolar plate with cathode support structure of the present invention.

[0022] Figure 4 This is a schematic diagram of the bipolar plate with an anode support structure according to the present invention.

[0023] Figure 5 This is a schematic diagram of the structure of the elastic mesh of the present invention.

[0024] Figure 6 This is a schematic diagram of the structure of the mesh of the present invention.

[0025] Figure 7 This is a schematic diagram of the mastoid plate of the present invention, wherein (a) is a front view of the mastoid plate and (b) is a side view of the mastoid plate.

[0026] Figure 8 This is a schematic diagram showing the thickness of the hydrogen-side and oxygen-side regions of the bipolar plate of the present invention.

[0027] Figure 9 This is a schematic diagram showing the thickness of the first flexible support structure and the second rigid support structure of the present invention.

[0028] Figure 10 This is a schematic diagram of the alkaline electrolytic cell of the present invention.

[0029] Figure 11 This is an axial view of the end face of the alkaline electrolytic cell of the present invention.

[0030] Figure 12 This is a distribution curve of the hydrogen content on the gas side inside the electrolysis chamber.

[0031] Figure 13 This is a comparison chart of the deformation modulus attenuation rate between the traditional double-sided elastic mesh structure and the spliced ​​support structure of this invention.

[0032] Figure 14 The images show temperature cloud maps of a traditional circular electrolysis chamber and the electrolysis chamber of the present invention, where (a) is the temperature cloud map of the traditional circular electrolysis chamber and (b) is the temperature cloud map of the electrolysis chamber of the present invention.

[0033] Figure 15 This is a comparison chart of the current efficiency of the alkaline electrolytic cell of the present invention and a traditional circular alkaline electrolytic cell.

[0034] In the diagram: 1. Bipolar plate; 11. Main alkaline solution channel; 12. Alkaline solution manifold channel; 13. Main gas-liquid channel; 14. Gas-liquid manifold channel; 2. Cathode support structure; 21. First flexible support structure; 22. First rigid support structure; 3. Cathode electrode; 4. Diaphragm; 5. Anode electrode; 6. Anode support structure; 61. Second rigid support structure; 62. Second flexible support structure; 7. Sealing gasket; 100. Electrolysis chamber; 200. End pressure plate; 300. Pull rod. Detailed Implementation

[0035] like Figures 1-11 As shown, the present invention provides an electrolysis chamber 100, which includes two bipolar plates 1, and a cathode support structure 2, a cathode electrode 3, a diaphragm 4, a cathode electrode 5, and an anode support structure 6. The cathode support structure 2, cathode electrode 3, diaphragm 4, cathode electrode 5, and anode support structure 6 are sequentially stacked between the two bipolar plates 1 along the axial direction of the electrolysis chamber 100, which is its stacking direction when applied to an alkaline electrolytic cell. Figure 1 Taking the perspective as an example, the axial direction of the electrolysis chamber 100 is... Figure 1 Left and right directions from a viewing angle. The negative electrode 3 and one of the bipolar plates 1 ( Figure 1 A hydrogen-side region is formed between the cathode surface of the bipolar plate 1 located on the left side, and the cathode support structure 2 is specifically located within the hydrogen-side region. The anode 5 and the other bipolar plate 1 ( Figure 1 An oxygen-side region is formed between the anode surfaces of the bipolar plates 1 on the right side, and the anode support structure 6 is specifically located within this oxygen-side region. The diaphragm 4 is specifically located between the cathode 3 and the anode 5. The electrolysis chamber 100 also includes a sealing gasket 7, which is disposed between the two bipolar plates 1, with its inner side located at the edge of the diaphragm 4. The sealing gasket 7 serves to seal the electrolysis chamber 100.

[0036] The two bipolar plates 1, as well as the cathode support structure 2, cathode electrode 3, diaphragm 4, anode electrode 5, and anode support structure 6, are all elliptical, with the major axis of the ellipse aligned along the height of the electrolysis chamber 100. This results in the electrolysis chamber 100 being an ellipse with its major axis aligned along its height. The height of the electrolysis chamber 100 is its vertical orientation when applied to an alkaline electrolytic cell. The alkali main channel 11 and alkali manifold channel 12 of the bipolar plates 1 are specifically located in the bottom region of the electrolysis chamber 100, while the gas-liquid main channel 13 and gas-liquid manifold channel 14 of the bipolar plates 1 are specifically located in the top region of the electrolysis chamber 100.

[0037] The cathode support structure 2 includes a first flexible support structure 21 and a first rigid support structure 22 that are spliced ​​together. That is, the first flexible support structure 21 and the first rigid support structure 22 are arranged adjacent to each other along a certain dividing line, and the first flexible support structure 21 and the first rigid support structure 22 do not overlap on the axial projection plane of the cathode support structure 2. The aforementioned dividing line is the splicing boundary of the first flexible support structure 21 and the first rigid support structure 22. The first flexible support structure 21 is located in the lower region of the electrolysis chamber 100, and the first rigid support structure 22 is located in the upper region of the electrolysis chamber 100. The anode support structure 6 includes a second rigid support structure 61 and a second flexible support structure 62 arranged in a spliced ​​configuration. Specifically, the second rigid support structure 61 and the second flexible support structure 62, and the first flexible support structure 21 and the first rigid support structure 22, are arranged adjacent to each other along a certain boundary line. On the axial projection plane of the cathode support structure 2, the first flexible support structure 21 and the first rigid support structure 22 do not overlap. The second rigid support structure 61 is located in the lower region of the electrolysis chamber 100, and its outer contour coincides with that of the first flexible support structure 21 under the axial projection view of the electrolysis chamber 100. The second flexible support structure 62 is located in the upper region of the electrolysis chamber 100, and its outer contour coincides with that of the first rigid support structure 22 under the axial projection view of the electrolysis chamber 100. In other words, the splicing boundary between the second flexible support structure 62 and the first rigid support structure 22 coincides with the splicing boundary between the first flexible support structure 21 and the first rigid support structure 22 on the axial projection plane.

[0038] Among them, the first flexible support structure 21 and the second flexible support structure 62 are support structures with low deformation stiffness, with a deformation stiffness of 1MPa to 50MPa. They can adaptively compress under pressure to fit the corresponding electrode (cathode 3 or anode 5) and achieve "zero gap" between the electrode and the diaphragm 4. The first rigid support structure 22 and the second rigid support structure 61 are support structures with high deformation stiffness, with a deformation stiffness at least 6 times that of the first flexible support structure 21 and the second flexible support structure 62, such as above 300MPa, preferably 300MPa to 1000MPa. They do not undergo significant deformation or have minimal deformation under pressure.

[0039] The electrolysis chamber 100 provided by this invention is elliptical in shape, with its major axis aligned along its height. This shortens the flow path of the alkali solution along both sides, optimizes the gas-liquid distribution of the alkali solution between the electrodes, and creates a smoother flow path inside the electrolysis chamber 100. This effectively removes heat generated on the electrode surfaces in the areas on both sides of the chamber, eliminating the flow dead zones at the waist of traditional circular electrolysis chambers. This avoids high-temperature drying problems, reduces the risk of high-temperature creep aging of the flexible support structure, and simplifies the arrangement of flow channels on the surface of the main electrode plate of the bipolar plate 1, reducing processing difficulty and cost. Furthermore, the elliptical structure has no sharp-angle stress singularities, resulting in higher pressure resistance. Alkaline electrolytic cells composed of electrolysis chambers 100 with this elliptical structure exhibit higher overall structural stability during operation, helping to reduce safety hazards.

[0040] The cathode support structure 2 and the anode support structure 6 together form a reverse symmetrical splicing support structure inside the electrolysis chamber 100, with the hydrogen side region being soft at the bottom and hard at the top, and the oxygen side region being hard at the bottom and soft at the top. This not only matches the electrochemical reaction characteristics of the upper and lower parts of the hydrogen and oxygen sides, but also forms a more symmetrical mechanical constraint system. The lower part of the hydrogen side region has a low alkaline gas content and a violent reaction. The first flexible support structure 21 provides elastic bearing capacity and pressure equalization bonding, achieving a tighter contact and lower contact resistance. The oxygen side region produces less gas than the hydrogen side (1 / 3 of the gas produced by the hydrogen side). 2) The overall reaction is relatively mild, so the lower part of the oxygen side region adopts the second rigid support structure 61 to adapt to the low reaction intensity region. At the same time, the first flexible support structure 21 is rigidly supported in the axial direction of the electrolysis chamber 100 to provide displacement boundary limit. The upper part of the oxygen side region adopts the second flexible support structure 62 to supplement and ensure the reaction effect. The upper part of the hydrogen side region has an increased gas content and a weakened reaction. The first rigid support structure 22 is used to match the reaction requirements, and the second flexible support structure 62 is rigidly supported in the axial direction of the electrolysis chamber 100 to provide displacement boundary limit. Based on the matching reaction characteristics of the hydrogen-side and oxygen-side regions, the cathode support structure 2 and the anode support structure 6 complement each other in terms of soft / hard stiffness. The deformation freedom of the flexible support structure is restricted by the opposite rigid support structure, which constrains the unidirectional tensile and collapse displacement of the flexible support structure, alleviates the eccentric deformation and local compression deformation under the action of pressure difference fluctuation in the gas-liquid two-phase flow, and counteracts the support deformation vibration caused by the pressure difference pulsation in the gas-liquid two-phase flow. This significantly weakens the reciprocating deformation and high-frequency vibration of the flexible support structure, and delays the fatigue failure and aging rate of the flexible support structure.

[0041] Based on the synergistic effect of the elliptical structure and the reverse symmetrical splicing support structure, the temperature-pressure coupling failure of the support structure of the electrolysis chamber 100 is effectively suppressed. On the basis of achieving "zero gap" between the electrodes (cathode 3, anode 5) and the diaphragm 4, the overall stability and load-bearing capacity of the cathode support structure 2 and the anode support structure 6 are improved, thereby improving the support uniformity under long-term operation, avoiding problems such as increased contact resistance and uneven current density caused by uneven support, improving the current distribution uniformity under long-term operation, thereby improving the current efficiency and the overall stability of the alkaline electrolyzer, and reducing safety hazards caused by operational instability.

[0042] In this invention, the minor axis dimension of the bipolar plate 1, cathode support structure 2, cathode electrode 3, diaphragm 4, anode electrode 5, and anode support structure 6 is 0.5 to 0.9 times their major axis dimension. Taking the bipolar plate 1 as an example, the outer contour of the bipolar plate 1 is as follows: Figure 2 As shown, the semi-major axis dimension of the bipolar plate 1 is b The major axis dimension is 2 b The semi-minor axis dimension is a The minor axis dimension is 2. a .in b The characteristic radius of a traditional circular electrolysis chamber or its circular bipolar plate R Equally, the mathematical model of the elliptical bipolar plate 1 of this invention is as follows:

[0043] Right now a It is 0.5 b ~0.9 b By eliminating the dead zone in the circular waist region, the electrolysis chamber 100 is ensured to have a sufficient effective reaction area, balancing flow uniformity and electrolysis efficiency.

[0044] The processing method of the elliptical bipolar plate 1 is as follows: (1) Roll the carbon steel blank into an elliptical shape, weld the connection, and then temper to eliminate stress and avoid cracking. Then process the pole frame by milling machine and grind to remove burrs after processing; (2) Laser cut the main pole plate to form an elliptical main pole plate; (3) After welding the elliptical main pole plate and the elliptical pole frame with a laser welding machine, an elliptical bipolar plate 1 is formed.

[0045] Preferably, the splicing boundary between the first flexible support structure 21 and the first rigid support structure 22 is a straight line, which reduces the difficulty of processing the splicing edge of the flexible and rigid support structures. Since the splicing boundary between the second flexible support structure 62 and the first rigid support structure 22 coincides with the splicing boundary between the first flexible support structure 21 and the first rigid support structure 22 on the axial projection plane, the splicing boundary between the second flexible support structure 62 and the first rigid support structure 22 is a straight line with the same height position.

[0046] Further, the splicing boundary is preferably a straight line parallel to the short axis of the electrolysis chamber 100. The height parameter of the splicing boundary on the long axis of the electrolysis chamber 100 is obtained by simulation and then by selecting a characteristic value of the gas content on the hydrogen side of the electrolysis chamber 100. The selected characteristic value of the gas content is in the range of 30%~60%, preferably 50%. Since the gas content inside the electrolysis chamber 100 continuously increases from the bottom to the top, the reaction in the upper region is weaker and there are more accumulated bubbles compared to the lower region. By selecting the characteristic value of the gas content to calculate the height parameter of the splicing boundary inside the electrolysis chamber 100, the soft and hard partitions of the spliced ​​support structure can more accurately match the difference in reaction intensity between the upper and lower parts of the electrolysis chamber 100. It can also better adapt to the use of alkaline electrolyzers with different rated current densities, avoiding the problem of mismatch between the soft and hard partitions of the spliced ​​support structure and the reaction characteristics of the upper and lower parts of the electrolysis chamber 100 caused by directly dividing the splicing boundary based on experience.

[0047] In this invention, the method for obtaining the height parameter of the splicing boundary on the long axis of the electrolysis chamber 100 includes the following steps: S1. Based on the actual application scenario requirements, set the basic parameters of the electrolysis chamber 100 and the alkaline electrolysis cell to be used. These basic parameters include rated current density and geometric dimensions. S2. Based on the basic parameters described in S1, establish a three-dimensional geometric model of the electrolysis chamber 100 and the alkaline electrolysis cell to be used. According to the geometric characteristics inside the electrolysis chamber 100, construct a multi-physics numerical model. Through simulation of the multi-physics numerical model, obtain the distribution curve of the gas content on the hydrogen side inside the electrolysis chamber 100. S3. In the gas content contour curve distribution map obtained in S2, select a gas content feature value, and use image tools to perform grayscale recognition on the area below the curve containing the gas content feature value. Generate uniformly distributed random points on the gas content contour curve distribution map, count the number of points falling into the grayscale recognition area, and calculate the area of ​​the grayscale recognition area. S 灰 ; The desired splicing boundary height parameter on the major axis of the electrolysis chamber 100 is set as follows: y 界限 Then set the electrolysis chamber 100 to be located inside y 界限 Area of ​​the lower region S 下 = S 灰 ,pass S 灰 Calculated y 界限The value is obtained to determine the height parameter of the splicing boundary on the long axis of the electrolysis chamber 100.

[0048] By combining multiphysics numerical simulation with mathematical modeling to determine the splicing boundary, the soft and hard partition boundaries of the spliced ​​support structure can be calculated more accurately based on simulations of actual operating conditions (rated current density, geometric dimensions, etc.). This improves the accuracy of the coupling and matching between the soft and hard partitions of the spliced ​​support structure and the two-phase flow distribution and electrochemical reaction rate, avoiding the blindness of conventional empirical values. Furthermore, the obtained splicing boundary is a straight line. Compared to directly using the curve containing the gas content characteristic value as the splicing boundary, this invention reduces the difficulty of processing the splicing edges of the soft and hard support structure.

[0049] Step S2, as described above, specifically includes the following sub-steps: S21. Based on the basic parameters in S1, establish a three-dimensional geometric model of the electrolysis chamber 100 and the alkaline electrolysis cell to be used. S22. Based on the geometric features inside the electrolysis chamber 100, it is divided into multiple sub-regions. Each sub-region is meshed, and the mesh is imported into the simulation software. The aforementioned geometric features include the internal dimensions of the electrolysis chamber 100, the cathode 3, the anode 5, the diaphragm 4, and the flow channel structure on the surface of the main electrode plate of the bipolar plate 1. S23. Construct a multiphysics numerical model based on the geometric features in S22, and set the parameters required for the physical field numerical model: (a) The velocity and pressure distribution in the free flow domain were calculated using the Navier-Stokes equations to simulate the fluid flow in the electrolysis chamber 100; (b) Calculation of the two-phase flow distribution within the electrolysis chamber 100 using a coupled mixture model; (c) The potential and current distributions of the electrolysis chamber 100 were calculated using the Nernst equation and the Butler-Volmer equation; (d) The temperature distribution in the electrolysis chamber 100 was calculated using the coupled energy equations. The energy equations are as follows:

[0050] In the formula; C p For fluid heat capacity; Q m For heat source items; q It is the heat flux vector; ρ f For fluid density; T For temperature; t For time; u For speed.

[0051] S24. Through simulation calculation and post-processing using a multi-physics numerical model, the gas content and temperature distribution on the hydrogen side of electrolysis chamber 100 are obtained, and based on the gas content and temperature distribution, the isopleth curve distribution of the gas content on the hydrogen side of electrolysis chamber 100 is obtained.

[0052] Based on the specific sub-steps described above, the two-phase flow distribution and temperature distribution within the electrolysis chamber 100 can be obtained more comprehensively, providing a reliable data foundation for subsequent calculations of the splicing boundary. Specifically, the contour of the gas content contour curve distribution map is an ellipse identical to the contour of the hydrogen side inside the electrolysis chamber 100, and the area of ​​the gas content contour curve distribution map is the same as the axial projection plane area of ​​the hydrogen side of the electrolysis chamber 100. Figure 12 The diagram schematically shows the distribution of the isopleth curve of the hydrogen content inside the electrolysis chamber 100 after simulation calculation of an alkaline electrolyzer with rated current density. It can be seen that the gas content increases continuously from the bottom (alkaline inlet area) of the electrolysis chamber 100 to the top (gas-liquid outlet area), and the gas content can reach 70% near the outlet.

[0053] The aforementioned step S3 specifically includes the following sub-steps: S31. In the obtained gas content contour curve distribution map, select a gas content feature value, such as 50%, and use image tools to perform grayscale processing and recognition on the area of ​​the gas content contour curve distribution map located below the curve containing the gas content feature value. S32, generated in the gas content isopleth curve distribution map N A uniformly distributed random point, preferably The coordinates of each point ( x , y )satisfy: x ∈[- a , a ], y ∈[- b , b For example, in Python, you can use the numpy.random.uniform function to generate [random forms]. x and y coordinate; S33. Determine whether the random point belongs to the grayscale recognition area to filter valid random points; count the number of points that finally hit the grayscale recognition area through pixel recognition marking. N t ; S34. Calculate the area of ​​the grayscale recognition region. ,in S0 represents the area of ​​the gas content contour curve distribution map, which is the axial projection plane area of ​​the hydrogen side inside the electrolysis chamber 100. It can be calculated repeatedly (e.g., 3 to 4 times), and the average value of the multiple calculation results is taken as the area of ​​the final grayscale recognition region, thereby reducing the influence of random errors. The desired splicing boundary height parameter on the major axis of the electrolysis chamber 100 is set as follows: y 界限 ,refer to Figure 2 Coordinate system diagram, setting S 下 = S 灰 ,as well as ,in S 下 To be located in the elliptical plane area inside the electrolysis chamber 100 y 界限 The area below is determined according to the following c and S 下 The governing equations:

[0054] Solve using the bisection method or Newton's iteration method. c Value, to obtain y 界限 The value of this value is used to obtain the height parameter of the splicing boundary on the long axis of the electrolysis chamber 100. The foregoing provides a scheme to more scientifically and accurately delineate the splicing boundary by using the gas content characteristic value as a quantitative judgment indicator.

[0055] In this invention, the distance between the cathode support structure 2 and the anode support structure 6 and the inner side of the welding point between the bipolar plate 1 and the main board, as viewed from the axial projection angle of the electrolysis chamber 100, is 10mm to 20mm. The spacing between the first flexible support structure 21 and the first rigid support structure 22 in the splicing direction, and the spacing between the second rigid support structure 61 and the second flexible support structure 62 in the splicing direction, are both 10mm to 20mm. The calculated splicing boundary is located in the middle of this spacing. The aforementioned distances and spacings are used to provide tolerance tolerance during assembly.

[0056] The uncompressed free height of the first flexible support structure 21 in the axial direction of the electrolysis chamber 100 and the height of the first rigid support structure 22 in the axial direction of the electrolysis chamber 100, as well as the uncompressed free height of the second flexible support structure 62 in the axial direction of the electrolysis chamber 100 and the height of the second rigid support structure 61 in the axial direction of the electrolysis chamber 100, all satisfy a proportional relationship: Furthermore, the height of the first flexible support structure 21 after compression between the cathode electrode 3 and its corresponding bipolar plate 1 (i.e., the height of the first flexible support structure 21 after axial compression during assembly) is the same as the height of the first rigid support structure 22 in the axial direction of the electrolysis chamber 100. Similarly, the height of the second flexible support structure 62 after compression between the cathode electrode 3 and its corresponding bipolar plate 1 (i.e., the height of the second flexible support structure 62 after axial compression during assembly) is the same as the height of the second rigid support structure 61 in the axial direction of the electrolysis chamber 100. This proportional relationship ensures that the height of the flexible support structure is consistent with that of the rigid support structure after compression, while also ensuring that the flexible support structure provides elastic bearing capacity and pressure equalization for the corresponding electrodes, achieving "zero gap" between the electrode and the diaphragm 4. This avoids poor contact due to insufficient compression or accelerated aging of the soft support performance due to excessive compression, thus balancing electrochemical performance and the lifespan of the support structure.

[0057] The first flexible support structure 21 and the second flexible support structure 62 are as follows Figure 5 The elastic mesh shown is made of metal wire, preferably pure nickel wire, with a wire diameter of 0.19 mm and / or 0.25 mm. It is made using a double-strand, double-layer weaving process, through the interlacing of transverse and longitudinal metal wires. At least one of the transverse and longitudinal metal wires is wavy, so that the overall elastic mesh after weaving has a W-shaped waveform. The wavy spacing is 11 ± 1 mm, the resilience is ≥ 40%, and the height of the elastic mesh (i.e., the free height along the axial direction of the electrolysis chamber 100) is approximately 5.0 mm to 9.0 mm. Compared to other flexible support structures (such as helical spring structures, other elastic elements, and elastic nets of other structural shapes), the elastic net provided by this invention, with its double-strand braided structure, W-shaped structure, and rebound amount of ≥40%, not only provides stable and reliable elasticity, increases contact points, and reduces contact resistance, but also improves its resistance to plastic deformation. Furthermore, the W-shaped structure forms a flow channel, which facilitates the uniform flow of electrolyte, promotes the detachment and discharge of air bubbles, and enhances the turbulence effect of alkali solution, thereby improving the flow efficiency and uniformity of alkali solution.

[0058] The first rigid support structure 22 and the second rigid support structure 61 are plate meshes or nipple plates. Based on the channels between their holes or nipples, they can increase the turbulence effect of the alkali solution, thereby improving the flow efficiency and uniformity of the alkali solution. For example, plate meshes... Figure 6 As shown, this is a metal sheet, such as a nickel plate, with a fish-scale structure. It is formed by punching, shearing, and stretching into a plate-like mesh with diamond-shaped holes. Its long pitch is 20mm~28mm, short pitch is 10mm~15mm, stem width is 3mm~6mm, forming height (i.e., the height along the axial direction of the electrolytic chamber 100) is 3mm~6mm, and the nickel plate thickness is 0.1mm~0.3mm. (The text repeats itself here, so the translation will only include the first instance.) Figure 7 (a) and Figure 7As shown in (b), the material is nickel-plated carbon steel, which is stamped by mold to form a convex-concave spherical structure with a uniform distribution or a denser middle and sparser sides. The radius of each papilla is 5 mm to 10 mm, the height is 3 mm to 6 mm, and the interval between adjacent papillae is 20 mm to 30 mm.

[0059] Further, the first rigid support structure 22 and the second rigid support structure 61 of the present invention are preferably plate meshes, that is, the cathode support structure 2 and the anode support structure 6 are preferably combinations of elastic meshes and plate meshes. Compared with the nipple plate, the plate mesh has a fish-scale structure that provides continuous and unobstructed diamond-shaped flow channels at the fluid level, which enhances the turbulence of alkaline solution and the removal of bubbles, thereby reducing the accumulation of electrode gas film. At the mechanical level, the plate mesh is rigid and continuous, which can uniformly limit the elastic mesh on the opposite side and alleviate the eccentric deformation caused by alternating pressure difference. Therefore, the combination of elastic mesh and plate mesh is better than the combination of elastic mesh and nipple plate in terms of both fluid flow uniformity and mechanical constraint stability.

[0060] The thickness of the hydrogen-side region formed between the cathode 3 and the corresponding cathode surface of the bipolar plate 1 in the axial direction of the electrolysis chamber 100 is [missing information]. The oxygen-side region formed between the anode 5 and its corresponding bipolar plate 1 anode surface has a thickness along the axial direction of the electrolysis chamber 100 of [thickness value missing]. According to the chemical formula:

[0061] The preferred one and The relationship is: This provides more reaction space and fluid channels for the hydrogen-side region, which produces a larger amount of gas, optimizing the hydrodynamic characteristics on both sides and improving the overall electrolysis efficiency. For example... Figure 9 As shown, the thicknesses of the cathode support structure 2 and the anode support structure 6 correspond to the thicknesses of the hydrogen-side region and the oxygen-side region, respectively.

[0062] The present invention also provides an alkaline electrolytic cell, such as... Figure 10 and Figure 11 As shown, the alkaline electrolytic cell includes two end plates 200 and several electrolytic chambers 100 as described above. The electrolytic chambers 100 are stacked sequentially between the two end plates 200 along the axial direction of the alkaline electrolytic cell, and are arranged in series. Two adjacent electrolytic chambers 100 along the axial direction of the alkaline electrolytic cell share a bipolar plate 1. The two end plates 200 are fastened by several tie rods 300, nuts, and disc springs.

[0063] This alkaline electrolyzer, composed of the aforementioned electrolysis chamber 100, optimizes the gas-liquid distribution of the alkaline solution between electrodes. This allows for a smoother flow path within the electrolysis chamber 100, effectively removing heat generated on the electrode surfaces in the areas on both sides of the chamber. This eliminates the flow dead zones at the waist of traditional circular electrolysis chambers, preventing high-temperature drying and reducing the risk of high-temperature creep aging of the flexible support structure. It also simplifies the arrangement of flow channels on the main electrode surface of the bipolar plate 1, reducing processing difficulty and cost. Furthermore, the elliptical structure eliminates sharp-angle stress singularities, resulting in higher pressure resistance. The alkaline electrolyzer composed of electrolysis chambers 100 with this elliptical structure exhibits greater overall structural stability during operation, helping to reduce safety hazards. Furthermore, based on the synergy between the elliptical structure and the reverse symmetrical splicing support structure, the temperature-pressure coupling failure of the electrolysis chamber 100 support structure is effectively suppressed. On the basis of achieving zero gap between the electrodes (cathode 3, anode 5) and the diaphragm 4, the overall stability and load-bearing capacity of the cathode support structure 2 and the anode support structure 6 are improved, thereby improving the support uniformity under long-term operation, avoiding problems such as increased contact resistance and uneven current density caused by uneven support, improving the current distribution uniformity under long-term operation, thereby improving current efficiency and the overall stability of alkaline electrolysis cell operation, and reducing safety hazards caused by operational instability.

[0064] Taking a 0.5 standard cubic alkaline electrolytic cell with a bipolar plate diameter of 200 cm, a cell temperature of approximately 85℃, and a 30% KOH electrolyte as an example, elastic mesh is installed on both sides of the anode and cathode in one part of the electrolysis chamber, forming a double-sided flexible support structure. In another part of the electrolysis chamber, a reverse symmetrical splicing support structure as described in this invention is used, specifically the lower soft-upper hard cathode support structure 2 and the lower hard-upper soft anode support structure 6. This is a combination of elastic mesh and plate mesh, with the splicing boundary located at the center of the bipolar plate 1. The elastic mesh specifications are: 0.19 mm nickel wire diameter, 11 mm corrugation spacing, and a rated inter-electrode spacing clamping force of approximately 20 kPa; the plate mesh specifications are: long pitch 22 mm, short pitch 13 mm, stem width 4 mm, and nickel plate thickness 0.2 mm.

[0065] Wave height data were measured at 6 randomly selected points, such as... Figure 13As shown, for the double-sided flexible support structure, the equivalent deformation modulus decays by approximately 10-24% over 920 hours, and nickel wire aging and elastic failure are prone to occur later. For the spliced ​​support structure of this invention, the rigid support structure provides unilateral rigid restraint, offsetting the alternating pulsating force of the two-phase flow and suppressing reciprocating deformation and creep. The equivalent deformation modulus decays by approximately 5%-11% over 920 hours, significantly reducing permanent deformation. Under the same operating conditions, the average decay rate of the double-sided flexible support structure is 2.2 times that of this invention. Therefore, the decay rate of the support structure of this invention is lower, thus reducing the frequency of support structure replacement and lowering the operation and maintenance costs of the alkaline electrolytic cell.

[0066] A simulation comparison was conducted between a traditional circular electrolysis chamber and the electrolysis chamber 100 of this invention. The traditional circular electrolysis chamber has a bipolar plate diameter of 0.8m and a single circular electrolysis chamber height (axial thickness) of 8mm. Both sides of the anode and cathode are equipped with elastic mesh, forming a double-sided flexible support structure. The electrolysis chamber 100 of this invention has a bipolar plate 1 with a major axis dimension of 0.8m and a minor axis dimension of 0.68m (i.e., 0.85 times the major axis dimension). A single electrolysis chamber 100 has a height (axial thickness) of 8mm and employs the lower soft upper hard cathode support structure 2 and the lower hard upper soft anode support structure 6 of this invention. Specifically, it is a combination of elastic mesh and plate mesh, with the height boundary of the splicing point located at the center of the bipolar plate 1. Figure 14 The temperature cloud maps of a traditional circular electrolysis chamber and the electrolysis chamber 100 of this invention are shown in comparison. Figure 15 A comparison chart showing the current efficiency of a conventional circular alkaline electrolyzer and the alkaline electrolyzer of this invention is presented.

[0067] in, Figure 14 (a) is a temperature contour map of a traditional circular electrolysis chamber. Figure 14 (b) is a temperature cloud map of the electrolysis chamber 100 of the present invention. As can be seen from the comparison, the waist area (white dashed circle) on both sides of a traditional circular electrolysis chamber is prone to forming a flow dead zone. This results in poor electrolyte mass transfer, making it impossible to replenish electrolyte and dissipate heat in a timely manner, thus forming a high-temperature dry area. The temperature difference between the waist and the middle area can reach up to 15°C, easily causing the flexible support structure in this area to age and fail first, seriously threatening the safety of the hydrogen production equipment. Figure 14 As shown in (b), the elliptical electrolysis chamber 100 avoids this phenomenon, effectively eliminating the flow dead zone and avoiding the high-temperature drying area.

[0068] according to Figure 15 It can be seen that, because the alkaline solution distribution in the inter-electrode gas-liquid distribution of the alkaline electrolytic cell 100 of the present invention is more uniform, the number of alkaline solution manifold channels 12 and gas-liquid manifold channels 14 required can be reduced by 33% to 50%, thereby reducing the Joule heat dissipated by the ion fluid through the bypass channel and effectively improving the current efficiency. Figure 15 As shown, at 3000A / m 2At a given current density, the current efficiency performance of the alkaline electrolyzer of this invention is improved by 1.6%.

[0069] 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.

[0070] 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. An electrolysis chamber, characterized in that, It includes two bipolar plates (1), and also includes a cathode support structure (2), a cathode electrode (3), a diaphragm (4), a cathode electrode (5), and an anode support structure (6) stacked sequentially between the two bipolar plates (1) along the axial direction of the electrolysis chamber (100). The two bipolar plates (1), the cathode support structure (2), the cathode electrode (3), the diaphragm (4), the cathode electrode (5), and the anode support structure (6) are all elliptical, and the major axis of the ellipse is set along the height direction of the electrolysis chamber (100). The cathode support structure (2) includes a first flexible support structure (21) and a first rigid support structure (22) that are spliced ​​together. The first flexible support structure (21) is located in the lower region of the electrolysis chamber (100), and the first rigid support structure (22) is located in the upper region of the electrolysis chamber (100). The anode support structure (6) includes a second rigid support structure (61) and a second flexible support structure (62) that are spliced ​​together. The second rigid support structure (61) is located in the lower region of the electrolysis chamber (100), and the outer contours of the second rigid support structure (61) and the first flexible support structure (21) coincide in the axial projection view of the electrolysis chamber (100). The second flexible support structure (62) is located in the upper region of the electrolysis chamber (100), and the outer contours of the second flexible support structure (62) and the first rigid support structure (22) coincide in the axial projection view of the electrolysis chamber (100).

2. The electrolysis chamber as described in claim 1, characterized in that, The minor axis dimensions of the bipolar plate (1), cathode support structure (2), cathode electrode (3), diaphragm (4), anode electrode (5) and anode support structure (6) are all 0.5 to 0.9 times their major axis dimensions.

3. The electrolysis chamber as described in claim 2, characterized in that, The joint boundary between the first flexible support structure (21) and the first rigid support structure (22) is a straight line.

4. The electrolysis chamber as described in claim 3, characterized in that, The splicing boundary is a straight line parallel to the short axis of the electrolysis chamber (100). The height parameter of the splicing boundary on the long axis of the electrolysis chamber (100) is obtained by selecting the gas content characteristic value after obtaining the gas content contour curve of the hydrogen side of the electrolysis chamber (100) through simulation.

5. The electrolysis chamber as described in claim 4, characterized in that, The method for obtaining the height parameter of the splicing boundary on the long axis of the electrolysis chamber (100) includes the following steps: S1. Set the basic parameters of the electrolysis chamber (100) and the alkaline electrolysis cell to be used, including the rated current density and geometric dimensions; S2. Based on the basic parameters described in S1, establish a three-dimensional geometric model of the electrolysis chamber (100) and the alkaline electrolysis cell to be used. Based on the geometric characteristics inside the electrolysis chamber (100), construct a multi-physics numerical model. Through simulation of the multi-physics numerical model, obtain the distribution curve of the gas content on the hydrogen side inside the electrolysis chamber (100). S3. In the gas content contour curve distribution map obtained in S2, select a gas content feature value, and use image tools to perform grayscale recognition on the area below the curve containing the gas content feature value in the gas content contour curve distribution map. Generate uniformly distributed random points in the gas content contour curve distribution map, count the number of points falling into the grayscale recognition area, and calculate the area of ​​the grayscale recognition area. S 灰 ; The desired splicing boundary height parameter inside the electrolysis chamber (100) is set as follows: y 界限 Then, the electrolysis chamber (100) is located inside... y 界限 Planar area of ​​the lower region S 下 = S 灰 ,pass S 灰 Calculated y 界限 The value of is obtained to obtain the height parameter of the splicing boundary on the long axis of the electrolytic cell (100).

6. The electrolysis chamber as described in any one of claims 1-5, characterized in that, The uncompressed free height of the first flexible support structure (21) in the axial direction of the electrolysis chamber (100) and the height of the first rigid support structure (22) in the axial direction of the electrolysis chamber (100), as well as the uncompressed free height of the second flexible support structure (62) in the axial direction of the electrolysis chamber (100) and the height of the second rigid support structure (61) in the axial direction of the electrolysis chamber (100), all satisfy the proportional relationship: ; Furthermore, the height of the first flexible support structure (21) after compression between the cathode electrode (3) and the cathode surface of its corresponding bipolar plate (1) is the same as the height of the first rigid support structure (22) in the axial direction of the electrolytic chamber (100), and the height of the second flexible support structure (62) after compression between the cathode electrode (3) and the anode surface of its corresponding bipolar plate (1) is the same as the height of the second rigid support structure (61) in the axial direction of the electrolytic chamber (100).

7. The electrolysis chamber as described in claim 6, characterized in that, The first flexible support structure (21) and the second flexible support structure (62) are elastic nets. The elastic nets are woven by interlacing transverse and longitudinal metal wires, and at least one of the transverse and longitudinal metal wires is wavy, so that the elastic nets as a whole have a W-shaped waveform.

8. The electrolysis chamber as described in claim 7, characterized in that, The first rigid support structure (22) and the second rigid support structure (61) are plate mesh or nipple plates.

9. The electrolysis chamber as described in any one of claims 1-5, 7, and 8, characterized in that, The thickness of the hydrogen-side region formed between the cathode (3) and its corresponding bipolar plate (1) cathode surface in the axial direction of the electrolysis chamber (100) is: The thickness of the oxygen-side region formed between the anode (5) and the anode surface of its corresponding bipolar plate (1) in the axial direction of the electrolysis chamber (100) is... The and The relationship is: .

10. An alkaline electrolytic cell, characterized in that, It includes two end plates (200) and several electrolytic cells (100) as described in any one of claims 1-9. The several electrolytic cells (100) are stacked sequentially between the two end plates (200) along the axial direction of the alkaline electrolytic cell, and two adjacent electrolytic cells (100) along the axial direction of the alkaline electrolytic cell share a bipolar plate (1).

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