Partition walls of an electrolytic cell, partition wall assemblies, and the electrolytic cell

Abstract

This invention provides a partition wall, a partition wall assembly, and an electrolytic cell that can suppress gas accumulation even when the partition wall separating the anode and cathode chambers of the electrolytic cell has recesses. The partition wall (8) of the electrolytic cell has a first main surface (20) and a second main surface (22) located on the side opposite to the first main surface (20). The first main surface (20) includes a first flat portion (24) and a plurality of first recesses (36) that are recessed from the first flat portion (24). The edges (40) of the first recesses (36) are rounded. The second main surface (22) includes a second flat portion (30) and a plurality of second recesses (42) that are recessed from the second flat portion (30). The edges (46) of the second recesses (42) are rounded.

Description

Technical Field

[0001] This utility model relates to a partition wall for an electrolytic cell, a partition wall assembly, and an electrolytic cell. Background Technology

[0002] As an apparatus for producing hydrogen and oxygen, a bipolar alkaline water electrolyzer is known. In a bipolar alkaline water electrolyzer, multiple electrolyzer units and multiple diaphragms are alternately arranged. Each electrolyzer unit includes an anode disposed in an anode chamber, a cathode disposed in a cathode chamber, and a conductive partition wall dividing the anode and cathode chambers. Multiple ribs are provided on the first main surface of the partition wall, and the anode is fixed to the first main surface of the partition wall by means of these ribs. Thus, an anode chamber is defined between the first main surface of the partition wall and the anode. Similarly, multiple ribs are also provided on the second main surface of the partition wall (the side opposite to the first main surface), and the cathode is fixed to the second main surface of the partition wall by means of these ribs. Thus, a cathode chamber is defined between the second main surface of the partition wall and the cathode.

[0003] In a bipolar alkaline electrolyzer, multiple protrusions and recesses are provided on the first and second main surfaces of the partition wall instead of multiple ribs. In this case, the anode is fixed to the top of the protrusion on the first main surface, thereby defining an anode chamber between the first main surface and the anode. Similarly, the cathode is fixed to the top of the protrusion on the second main surface, thereby defining a cathode chamber between the second main surface and the cathode (see, for example, Patent Document 1).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2021 / 256472 Utility Model Content

[0007] Problems to be solved by utility models

[0008] However, if multiple recesses are formed on the first and second main surfaces of the partition wall, the gas generated at the electrodes may become trapped inside these recesses, leading to gas accumulation. If gas accumulation occurs, the flow of the electrode liquid within the electrode chamber becomes uneven, resulting in a concentration difference in the electrode liquid. If this concentration difference increases, the current distribution becomes uneven, leading to a decrease in electrolysis efficiency. Furthermore, this problem can occur not only in alkaline water electrolyzers used to produce hydrogen and oxygen, but also in other electrolyzers such as salt electrolyzers used to produce hydrogen, chlorine, and sodium hydroxide.

[0009] The present invention relates to a partition wall, a partition wall assembly, and an electrolytic cell that can suppress gas accumulation even when the partition wall separating the anode and cathode chambers of the electrolytic cell has a recess.

[0010] Solution for solving the problem

[0011] According to this utility model, a partition wall for an electrolytic cell is provided to solve the above-mentioned problems. That is,

[0012] Provides "a partition wall for an electrolytic cell that divides an anode chamber and a cathode chamber, wherein,

[0013] The partition wall of the electrolytic cell has a first main surface and a second main surface located on the side opposite to the first main surface.

[0014] The first main surface includes a first flat portion and a plurality of first recesses that are recessed from the first flat portion. The edges of the first recesses are rounded.

[0015] The second main surface includes a second flat portion and a plurality of second recesses that are recessed from the second flat portion, and the edges of the second recesses are R-machined.

[0016] Preferably, the first main surface includes a plurality of first protrusions in a mountain shape that protrude beyond the first flat portion, and the second main surface includes a plurality of second protrusions in a mountain shape that protrude beyond the second flat portion.

[0017] It is possible that a first inclined portion, inclined relative to the first flat portion, is provided between the first protrusion and the first recess on the first main surface, and a second inclined portion, inclined relative to the second flat portion, is provided between the second protrusion and the second recess on the second main surface. Preferably, the positions of the plurality of first recesses correspond to the positions of the plurality of second protrusions, and the positions of the plurality of second recesses correspond to the positions of the plurality of first protrusions.

[0018] The first protrusion, the second protrusion, the first recess, and the second recess can be hemispherical. Preferably, when the radius of curvature of the edges of the first and second recesses is set to R3, and the radius of curvature of the bottoms of the first and second recesses is set to R4, the ratio of the radii of curvature R4 / R3 is 0.1 or more and 19 or less. Alternatively, the bases of the first and second protrusions may be machined with an R-shape. Preferably, when the radius of curvature of the base of the first protrusion and the base of the second protrusion is set to R1, and the radius of curvature of the top of the first protrusion and the top of the second protrusion is set to R2, the ratio of the radii of curvature R2 / R1 is 0.6 or more and 40 or less; and when the radius of curvature of the edge of the first recess and the edge of the second recess is set to R3, and the radius of curvature of the bottom of the first recess and the bottom of the second recess is set to R4, the ratio of the radii of curvature R4 / R3 is 0.1 or more and 19 or less.

[0019] Alternatively, the first protrusion, the second protrusion, the first recess, and the second recess may be conical in shape, with rounded corners at the tops of the first and second protrusions, and at the bottoms of the first and second recesses. Preferably, when the radius of curvature of the edges of the first and second recesses is set to R7, and the radius of curvature of the bottoms of the first and second recesses is set to R8, the ratio of the radii of curvature R8 / R7 is 0.05 or more and 190 or less. Alternatively, the bases of the first and second protrusions may be machined with an R-shape. Preferably, when the radius of curvature of the base of the first protrusion and the base of the second protrusion is set to R5, and the radius of curvature of the top of the first protrusion and the top of the second protrusion is set to R6, the ratio of the radii of curvature R6 / R5 is 0.6 or more and 400 or less; and when the radius of curvature of the edge of the first recess and the edge of the second recess is set to R7, and the radius of curvature of the bottom of the first recess and the bottom of the second recess is set to R8, the ratio of the radii of curvature R8 / R7 is 0.05 or more and 190 or less.

[0020] It is possible that the first protrusion, the second protrusion, the first recess, and the second recess are frustum-shaped, and that the bottom periphery of the first recess and the bottom periphery of the second recess are rounded (R-shaped). Preferably, when the radius of curvature of the edges of the first and second recesses is set to R11, and the radius of curvature of the bottom periphery of the first and second recesses is set to R12, the ratio of the radii of curvature R12 / R11 is 0.05 or more and 50 or less. Alternatively, the bases of the first and second protrusions, as well as the top periphery of the first and second protrusions, are rounded (R-shaped). Preferably, when the radius of curvature of the base of the first protrusion and the base of the second protrusion is set to R9, and the radius of curvature of the top periphery of the first protrusion and the top periphery of the second protrusion is set to R10, the ratio of the radii of curvature R10 / R9 is 0.1 or more and 100 or less; and when the radius of curvature of the edge of the first recess and the edge of the second recess is set to R11, and the radius of curvature of the bottom periphery of the first recess and the bottom periphery of the second recess is set to R12, the ratio of the radii of curvature R12 / R11 is 0.05 or more and 50 or less.

[0021] Furthermore, according to this invention, a partition wall assembly is provided to solve the above-mentioned problems. Specifically, it provides "a partition wall assembly, wherein the partition wall assembly includes a partition wall as described above and a partition wall support frame supporting the periphery of the partition wall." The partition wall may be circular, and the partition wall support frame may be annular. The partition wall assembly of this invention can include electrodes or current collectors joined to the tops of each of the plurality of first protrusions and current collectors or electrodes joined to the tops of each of the plurality of second protrusions. Preferably, the partition wall assembly of this invention includes electrodes or current collectors joined to the tops of each of the plurality of first protrusions by welding and current collectors or electrodes joined to the tops of each of the plurality of second protrusions.

[0022] Alternatively, the partition wall assembly of this invention may include an electrode or current collector joined by welding to the top of each of the plurality of first protrusions and a current collector or electrode joined by welding to the top of each of the plurality of second protrusions.

[0023] Furthermore, according to this utility model, an electrolytic cell is provided to solve the above-mentioned problems. That is, "an electrolytic cell is provided which alternately arranges a plurality of partition wall assemblies and a plurality of membrane assemblies as described above, wherein the membrane assembly includes a membrane and a membrane support frame supporting the periphery of the membrane."

[0024] Effects of the utility model

[0025] In this invention, the edges of the first and second recesses are R-processed, so that the gas generated by the electrode will not be trapped inside the first and second recesses, thus suppressing gas accumulation. Therefore, the flow of the electrode liquid in the electrode chamber is homogenized, and the concentration difference of the electrode liquid in the electrode chamber will not become excessively large. As a result, the current distribution is homogenized, thus preventing a decrease in electrolysis efficiency. Attached Figure Description

[0026] Figure 1 This is a schematic partial cross-sectional view of the electrolytic cell of this utility model.

[0027] Figure 2 yes Figure 1 A schematic partial cross-sectional view of the electrolytic cell shown.

[0028] Figure 3 yes Figure 1 The main view of the partition wall component shown.

[0029] Figure 4(a) is Figure 3 A partial sectional view along line IV-IV in Figure 4(b) is a partial sectional view of a partition wall with an inclined portion between the protrusion and the recess (this sectional view is equivalent to the sectional view in Figure 4(a)).

[0030] Figure 5 This is an explanatory diagram (partial enlarged view of Fig. 4(a)) used to illustrate the radius of curvature R1 of the base of the first protrusion.

[0031] Figure 6 This is an explanatory diagram (partial enlarged view of Figure 4(a)) used to illustrate the radius of curvature R2 of the top of the first protrusion.

[0032] Figure 7 This is an explanatory diagram (partial enlarged view of Fig. 4(a)) used to illustrate the radius of curvature R3 of the edge of the first depression.

[0033] Figure 8 This is an explanatory diagram (partial enlarged view of Figure 4(a)) used to illustrate the radius of curvature R4 of the bottom of the first depression.

[0034] Figure 9 yes Figure 1 The front view of the membrane assembly shown.

[0035] Figure 10(a) is a partial cross-sectional view of the partition wall of the first modified example (this cross-section corresponds to the cross-section of Figure 4(a)). Figure 10(b) is a partial cross-sectional view of the partition wall of the first modified example in which an inclined portion is provided between the protrusion and the recess (this cross-section corresponds to the cross-section of Figure 4(a)).

[0036] Figure 11(a) is a partial cross-sectional view of the partition wall of the second modified example (this cross-section corresponds to the cross-section of Figure 4(a)). Figure 11(b) is a partial cross-sectional view of the partition wall of the second modified example in which an inclined portion is provided between the protrusion and the recess (this cross-section corresponds to the cross-section of Figure 4(a)).

[0037] Figure 12 This is an explanatory diagram (partial enlarged view of Fig. 11(a)) used to illustrate the radius of curvature R10 of the top periphery of the first protrusion in the second variation.

[0038] Figure 13 This is an explanatory diagram (partial enlarged view of Fig. 11(a)) used to illustrate the radius of curvature R12 of the bottom periphery of the first recess in the second variation example.

[0039] Explanation of reference numerals in the attached figures

[0040] 2. Electrolytic cell; 4. Partition wall assembly; 6. Membrane module; 8. Partition wall; 10. Partition wall support frame; 12. Electrode; 14. Current collector; 16. Anode chamber; 18. Cathode chamber; 20. First main surface of partition wall; 22. Second main surface of partition wall; 24. First flat portion; 26. First protrusion; 26a. Top of the first protrusion; 26b. Peripheral edge of the top of the first protrusion (second variation); 28. Base of the first protrusion; 30. Second flat portion; 32. Second protrusion; 32a. Second protrusion 32b, the top periphery of the second protrusion (second variation); 34, the base of the second protrusion; 36, the first depression; 36a, the bottom of the first depression; 36b, the bottom periphery of the first depression (second variation); 40, the edge of the first depression; 42, the second depression; 42a, the bottom of the second depression; 42b, the bottom periphery of the second depression (second variation); 46, the edge of the second depression; 76, cushioning material; 78, electrode; 80, membrane; 82, membrane support frame; 84, gasket. Detailed Implementation

[0041] Hereinafter, with reference to the accompanying drawings, preferred embodiments of the electrolytic cell of the present invention, including the partition wall, the partition wall assembly, and the electrolytic cell, will be described.

[0042] (Electrolytic Cell 2)

[0043] Reference Figure 1 and Figure 2 To illustrate, the electrolyzer, indicated by reference numeral 2 in the attached figure, is a zero-gap bipolar electrolyzer with membrane and electrode contact. The electrolyzer 2 comprises multiple partition wall assemblies 4 and multiple membrane assemblies 6. The partition wall assemblies 4 and membrane assemblies 6 are in... Figure 1 The electrolytic cells 2, indicated by the middle arrow X, are alternately arranged in the depth direction (X direction). Furthermore, Figure 1 The Y-direction indicated by the middle arrow Y is orthogonal to the X-direction and is the width direction of electrolytic cell 2. Additionally, Figure 1 The Z direction indicated by the middle arrow Z is the up-down direction orthogonal to the X and Y directions.

[0044] (Separator Component 4)

[0045] The partition wall assembly 4 includes a partition wall 8 and a partition wall support frame 10 supporting the periphery of the partition wall 8. The partition wall assembly 4 of this embodiment further includes an electrode 12 disposed on one side of the partition wall 8 in the X direction and a current collector 14 disposed on the other side of the partition wall 8 in the X direction. In this embodiment, a buffer material 76 (described later) and an electrode 78 are also provided on the side of the current collector 14 opposite to the contact surface with the partition wall 8. Alternatively, the current collector 14 and the electrode 12 may be disposed on one side of the partition wall 8 in the X direction, and the current collector 14, the buffer material 76, and the electrode 78 may be disposed on the other side of the partition wall 8 in the X direction.

[0046] (Divider 8)

[0047] Separator 8 divides the anode chamber 16 and the cathode chamber 18 (see reference) Figure 2 ).like Figure 3 As shown in Figure 4(a), the partition wall 8 in this embodiment is a circular sheet having a first main surface 20 and a second main surface 22 located on the side opposite to the first main surface 20. However, the shape of the partition wall 8 is not limited to a circular sheet; for example, it can also be a rectangular sheet. In such cases, the shape of the partition wall support frame 10, described later, can be a shape corresponding to the partition wall 8. For example, if the partition wall 8 is a rectangular sheet, then the partition wall support frame 10 is also rectangular. Furthermore, the size of the partition wall 8 can be appropriately determined considering the electrolytic capacity of the electrolytic cell 2, operating conditions, installation area, cost, etc. For example, when the partition wall 8 is a circular sheet, the diameter of the partition wall 8 can be 0.1 m to 5 m; when the partition wall 8 is a rectangular sheet, one side of the partition wall 8 can be 0.1 m to 5 m, but it is not limited to these values. The partition wall 8 can be formed of a conductive material (e.g., a metal material such as steel plate). The surface of the partition wall 8 can also be surface-treated with nickel plating or other methods. The thickness of the partition wall 8 can be appropriately determined by taking into account the shape, size and material of the partition wall 8, the number of protrusions, the number of recesses, their shape and arrangement, etc. For example, it is 0.5 mm or more and 10 mm or less, preferably 1 mm or more and 7 mm or less, and more preferably 2 mm or more and 5 mm or less.

[0048] (1st main side 20)

[0049] The first main surface 20 includes a first flat portion 24 and a plurality of first protrusions 26 in a mountain shape that protrude beyond the first flat portion 24. In this embodiment, the first protrusions 26 are hemispherical in shape, with their diameter gradually decreasing as they move away from the first flat portion 24. The radius of curvature of the first protrusions 26 can be, for example, 3 mm or more and 20 mm or less, more preferably 5 mm or more and 15 mm or less, and even more preferably 7 mm or more and 10 mm or less. The height H of the first protrusions 26 relative to the first flat portion 24 can be, for example, 3 mm or more and 20 mm or less, more preferably 5 mm or more and 15 mm or less, and even more preferably 7 mm or more and 10 mm or less.

[0050] The arrangement of the plurality of first protrusions 26 is arbitrary. For example, the plurality of first protrusions 26 can be aligned along the width direction (Y direction) and along the vertical direction (Z direction) of the electrolytic cell 2. Alternatively, the plurality of first protrusions 26 can be arranged in an alternating pattern or in a concentric circle pattern. In addition, the number and spacing of the plurality of first protrusions 26 can also be arbitrarily set.

[0051] The base 28 of the first protrusion 26 may or may not be R-machined. The base 28 is the boundary between the first flat portion 24 and the first protrusion 26, or the boundary between the first inclined portion 38 (described later) and the first protrusion 26. If the base 28 of the first protrusion 26 in the first main surface 20 is not R-machined, the electrode liquid after contacting the first protrusion 26 diffuses along the first flat portion 24, thus improving the uniformity of the electrode liquid in the electrode chamber. Moreover, when the electrode liquid contacts the first protrusion 26, a shear force is applied relative to the flow of the electrode liquid, which generates an effect that makes the bubbles contained in the electrode liquid smaller, thus further promoting the homogenization of the electrode liquid and is expected to contribute to improving the electrolysis efficiency. In addition, when R-machined on the base 28 of the first protrusion 26, it is important to R-machine the base 28 of multiple first protrusions 26 equally. However, when the first protrusion 26 is formed, for example, by stamping, the forces act differently at the center and ends (e.g., the ends in the Y and Z directions) of the partition wall 8. Therefore, it is generally difficult to uniformly R-machine the base 28. Not only does the protrusion shape of the first protrusion 26 at the end of the partition wall 8 tend to lose symmetry, but there is also a tendency for deviations in the orientation of the tops 26a (from the direction perpendicular to the first main surface 20) among the multiple first protrusions 26 within the first main surface 20. In such cases, fixing the electrode to the top 26a of the first protrusion 26 may compromise electrode flatness, becoming a major problem in zero-gap electrolytic cells. For these reasons, it is preferable not to R-machine the base 28 of the first protrusion 26, but R-machine the base 28 of the first protrusion 26 may be performed for reasons related to the manufacturing and processing of the partition wall 8.

[0052] As shown in Figure 4(a), the base 28 of the first protrusion 26 can also be R-machined in the partition wall 8. When R-machined, it is preferable to perform it on the entire circumference of the base 28. By R-machined the base 28, the gas generated by the electrode flows in a manner that prevents accumulation near the first protrusion 26. As a result, the accumulation of gas near the first protrusion 26 can be suppressed.

[0053] When the radius of curvature of the base 28 of the first protrusion 26 is set to R1 and the radius of curvature of the top 26a of the first protrusion 26 is set to R2, the ratio of the radii of curvature R2 / R1 is preferably 0.6 or more and 40 or less. This improves the smooth flow of gas generated by the electrode near the first protrusion 26. Furthermore, the radius of curvature R1 of the base 28 can, for example, be 0.5 mm or more and 5 mm or less. If the radius of curvature R1 of the base 28 is 0.5 mm or more and 5 mm or less, the effects of the electrode liquid diffusing along the first flat portion 24 into the electrode chamber and the shear force relative to the flow of the electrode liquid can also be obtained simultaneously.

[0054] Reference Figure 5 The radius of curvature R1 of the base 28 of the first protrusion 26 will be explained. The intersection point of the straight line L1 extending along the first flat portion 24 and the tangent L2 of the first protrusion 26 passing through the base 28 is defined as P1. An auxiliary line L3 is defined that passes through the intersection point P1 and bisects the angle θ1 formed by the straight line L1 and the tangent L2. An imaginary circle C1 with a center O1 is assumed to exist on the auxiliary line L3. Furthermore, the radius of curvature R1 in this invention is defined as the imaginary circle C1 whose circumference passes through the intersection point Q1 of the base 28 of the first protrusion 26 and the auxiliary line L3, and whose circumference is tangent to both the straight line L1 and the tangent L2.

[0055] Reference Figure 6 The radius of curvature R2 of the top 26a of the first protrusion 26 will be explained. A straight line L1 extending along the first flat portion 24 and a straight line L4 passing through the top 26a of the first protrusion 26 and intersecting the straight line L1 perpendicularly are defined. An imaginary circle C2 with a center O2 is assumed to exist on the straight line L4. Furthermore, the radius of curvature R2 in this invention is defined as the imaginary circle C2 whose circumference passes through the top 26a of the first protrusion 26 and whose circumference overlaps most significantly with the outline of the first protrusion 26.

[0056] When determining the radii of curvature R1 and R2, for example, the partition wall 8 can be cut with a plane passing through the top 26a of the first protrusion 26 and perpendicular to the first main surface 20 of the partition wall 8 to expose the cross-sections corresponding to Figures 4(a) and 4(b), and the radii of curvature R1 and R2 can be directly measured in the cut surface of the partition wall 8 (corresponding to the cross-sections in Figures 4(a) and 4(b)) to determine the radii of curvature R1 and R2. Alternatively, the cross-sectional image of the partition wall 8 can be obtained by photographing the cut surface of the partition wall 8 (corresponding to the cross-sections in Figures 4(a) and 4(b), and the obtained cross-sectional image can be analyzed to determine the radii of curvature R1 and R2.

[0057] While the radii of curvature R1 and R2 can be determined by cutting the partition wall 8 as described above, it is preferable to determine them without cutting the partition wall 8. For example, resin, clay, plaster, or molding material is pressed against the first main surface 20 of the partition wall 8 to form a profile that imitates the shape of the first main surface 20 of the partition wall 8. Next, the profile is cut with a plane that passes through the point corresponding to the top 26a of the first protrusion 26 and is perpendicular to the plane corresponding to the first main surface 20 of the partition wall 8. Then, the cross-sectional image of the profile is obtained by photographing the cross-sectional surface, and the obtained cross-sectional image is analyzed to determine the radii of curvature R1 and R2 without cutting the partition wall 8.

[0058] (2nd main side 22)

[0059] Reference Figure 3 Continuing with Figure 4(a), the second main surface 22 includes a second flat portion 30 and a plurality of second protrusions 32 in a mountain shape that protrude beyond the second flat portion 30. In this embodiment, the second protrusions 32, like the first protrusions 26, are hemispherical in shape, with their diameter gradually decreasing as they move away from the second flat portion 30. The dimensions of the second protrusions 32 may be the same as or different from those of the first protrusions 26.

[0060] The arrangement of the multiple second protrusions 32 is arbitrary. For example, the multiple second protrusions 32 can be aligned along the width direction (Y direction) and along the vertical direction (Z direction) of the electrolytic cell 2. Alternatively, the multiple second protrusions 32 can be arranged in an alternating pattern or in a concentric circle pattern. In addition, the number and spacing of the multiple second protrusions 32 can also be arbitrarily set.

[0061] The base 34 of the second protrusion 32 may or may not be R-machined. The base 34 is the boundary between the second flat portion 30 and the second protrusion 32, or the boundary between the second inclined portion 44 (described later) and the second protrusion 32. If the base 34 of the second protrusion 32 in the second main surface 22 is not R-machined, the electrode liquid after contacting the second protrusion 32 diffuses along the second flat portion 30, thus improving the uniformity of the electrode liquid in the electrode chamber. Moreover, when the electrode liquid contacts the second protrusion 32, the shear force relative to the flow of the electrode liquid generates a force that makes the bubbles contained in the electrode liquid smaller, thus further promoting the homogenization of the electrode liquid and is expected to contribute to improving electrolysis efficiency. In addition, when R-machined on the base 34 of the second protrusion 32, it is important to R-machine the base 34 of multiple second protrusions 32 equally. However, when the second protrusion 32 is formed, for example, by stamping, the forces act differently at the center and ends (e.g., the ends in the Y and Z directions) of the partition wall 8. Therefore, it is generally difficult to uniformly R-machine the base 34. Not only does the protrusion shape of the second protrusion 32 at the ends of the partition wall 8 tend to lose symmetry, but there is also a tendency for deviations in the orientation of the tops 32a (from the direction perpendicular to the second main surface 22) among the multiple second protrusions 32 within the second main surface 22. In such cases, fixing the electrode to the top 32a of the second protrusion 32 may compromise electrode flatness, becoming a major problem in zero-gap electrolytic cells. For these reasons, it is preferable not to R-machine the base 34 of the second protrusion 32, but R-machine the base 34 of the second protrusion 32 may be performed for reasons related to the manufacturing and processing of the partition wall 8.

[0062] As shown in Figure 4(a), the base 34 of the second protrusion 32 may also be R-machined in the partition wall 8. When R-machined, it is preferable to perform it around the entire circumference of the base 34. By R-machined the base 34, the gas generated at the electrode flows in a manner that prevents accumulation near the second protrusion 32, thus suppressing gas accumulation near the second protrusion 32. The radius of curvature of the base 34 of the second protrusion 32 may be the same as or different from the radius of curvature of the base 28 of the first protrusion 26.

[0063] (Depression 36)

[0064] The first main surface 20 of this embodiment includes a plurality of first recesses 36 that are recessed from the first flat portion 24. As shown in FIG4(a), the positions of the plurality of first recesses 36 correspond to the positions of the plurality of second protrusions 32. That is, the arrangement, number, and spacing of the first recesses 36 correspond to the arrangement, number, and spacing of the second protrusions 32. In addition, the first recesses 36 are hemispherical in shape with their diameter gradually decreasing as they move away from the first flat portion 24. The radius of curvature of the first recesses 36 can be, for example, 2 mm or more and 19 mm or less, more preferably 3 mm or more and 15 mm or less, and even more preferably 4 mm or more and 10 mm or less. The depth D of the first recesses 36 relative to the first flat portion 24 can be, for example, 3 mm or more and 20 mm or less, more preferably 5 mm or more and 15 mm or less, and even more preferably 7 mm or more and 10 mm or less. The greater the depth D of the first recesses 36, that is, the deeper the first recesses 36, the greater the possibility that gas will be trapped in the first recesses 36 and form gas accumulation. However, as will be described later, by performing an R-process on the edge 40 of the first recess 36, the gas that has entered the first recess 36 is quickly discharged from the first recess 36 and will not remain in the first recess 36.

[0065] The diameter d of the first recess 36 can be, for example, 5 mm or more and 50 mm or less. As shown in FIG4(a), the diameter d is the diameter at the edge 40 of the first recess 36, that is, the maximum value of the diameter of the portion recessed from the first flat portion 24 of the first main surface 20 in the X-axis direction. When the diameter d of the first recess 36 is 5 mm or more and 50 mm or less, as will be described later, by performing R machining on the edge 40 of the first recess 36, the gas entering the first recess 36 can be easily and quickly discharged from the first recess 36.

[0066] As shown in Figure 4(a), the first recess 36 and the first protrusion 26 can be connected via the first flat portion 24. Alternatively, as shown in Figure 4(b), a first inclined portion 38 inclined relative to the first flat portion 24 may be provided between the first recess 36 and the first protrusion 26. When the first inclined portion 38 is provided, the gas generated by the electrode can flow more easily between the first recess 36 and the first protrusion 26.

[0067] An R-machining process is applied to the edge 40 of the first recess 36 on the first main surface 20. The edge 40 is the boundary between the first flat portion 24 and the first recess 36, or the boundary between the first inclined portion 38 and the first recess 36. The R-machining is preferably applied to the entire circumference of the edge 40. By applying the R-machining process to the edge 40, the gas generated at the electrode flows smoothly in the first recess 36, thus suppressing the accumulation of gas in the first recess 36.

[0068] When the radius of curvature of the edge 40 of the first recess 36 is set to R3 and the radius of curvature of the bottom 36a of the first recess 36 is set to R4, the ratio of the radii of curvature R4 / R3 is preferably 0.1 or more and 19 or less, more preferably 0.3 or more and 5 or less. This improves the smooth flow of gas generated at the electrode in the first recess 36. Furthermore, the radius of curvature R3 of the edge 40 can, for example, be 1 mm or more and 20 mm or less, more preferably 3 mm or more and 10 mm or less.

[0069] Reference Figure 7 The radius of curvature R3 of the edge 40 of the first recess 36 will be explained. The intersection point of the straight line L1 extending along the first flat portion 24 and the tangent L5 of the first recess 36 passing through the edge 40 is defined as P2. An auxiliary line L6 is defined that passes through the intersection point P2 and bisects the angle θ2 formed by the straight line L1 and the tangent L5. An imaginary circle C3 with a center O3 is assumed to exist on the auxiliary line L6. Furthermore, the radius of curvature R3 in this invention is defined as the imaginary circle C3 whose circumference passes through the intersection point Q2 of the edge 40 of the first recess 36 and the auxiliary line L6, and whose circumference is tangent to both the straight line L1 and the tangent L5.

[0070] Reference Figure 8 The radius of curvature R4 of the bottom 36a of the first recess 36 will be explained. A straight line L1 extending along the first flat portion 24 and a straight line L7 passing through the bottom 36a of the first recess 36 and intersecting the straight line L1 perpendicularly are defined. An imaginary circle C4 with a center O4 is assumed to lie on the straight line L7. Furthermore, the radius of curvature R4 in this invention is defined as the imaginary circle C4 whose circumference passes through the bottom 36a of the first recess 36 and whose circumference overlaps most significantly with the outline of the first recess 36.

[0071] The radii of curvature R3 and R4 can be obtained using the same method as the aforementioned radii of curvature R1 and R2.

[0072] When a first inclined portion 38, which is inclined relative to the first flat portion 24, is provided between the first recess 36 and the first protrusion 26 (see Figure 4(b)), the radius of curvature R1 of the base 28 of the first protrusion 26 is defined as P1, where the intersection of the straight line extending along the first inclined portion 38 and the tangent L2 of the first protrusion 26 passing through the base 28 is set, and the radius of curvature R1 is defined in the same way as described above. Furthermore, the radius of curvature R3 of the edge 40 of the first recess 36 when the first inclined portion 38 is provided is defined as P2, where the intersection of the straight line extending along the first inclined portion 38 and the tangent L5 of the first recess 36 passing through the edge 40 is set, and the radius of curvature R3 is defined in the same way as described above.

[0073] (Second Depression 42)

[0074] The second main surface 22 of this embodiment includes a plurality of second recesses 42 that are recessed from the second flat portion 30. The positions of the plurality of second recesses 42 correspond to the positions of the plurality of first protrusions 26, and the arrangement, number, and spacing of the second recesses 42 correspond to the arrangement, number, and spacing of the first protrusions 26. In addition, the second recesses 42 are hemispherical in shape, with their diameter gradually decreasing as they move away from the second flat portion 30. The size of the second recesses 42 may be the same as or different from the size of the first recesses 36. The greater the depth of the second recesses 42, that is, the deeper the second recesses 42, the greater the possibility that gas will be trapped in the second recesses 42 and form gas accumulation. However, as will be described later, by performing an R-processing on the edges 46 of the second recesses 42, the gas entering the second recesses 42 is quickly discharged from the second recesses 42 and will not be trapped in the second recesses 42.

[0075] The diameter of the second recess 42 is the same as the diameter d of the first recess 36, for example, it can be 5 mm or more and 50 mm or less. The diameter of the second recess 42 is the diameter at the edge 46 of the second recess 42, that is, the maximum value of the diameter of the portion recessed in the X-axis direction from the second flat portion 30 of the second main surface 22. When the diameter of the second recess 42 is 5 mm or more and 50 mm or less, as will be described later, by performing R machining on the edge 46 of the second recess 42, the gas entering the second recess 42 can be easily and quickly discharged from the second recess 42.

[0076] As shown in Figure 4(a), the second recess 42 and the second protrusion 32 can be connected via the second flat portion 30. Alternatively, as shown in Figure 4(b), a second inclined portion 44 inclined relative to the second flat portion 30 may be provided between the second recess 42 and the second protrusion 32. When the second inclined portion 44 is provided, the gas generated by the electrode can flow more easily between the second recess 42 and the second protrusion 32.

[0077] An R-machining is also applied to the edge 46 of the second recess 42 on the second main surface 22. Edge 46 is the boundary between the second flat portion 30 and the second recess 42, or the boundary between the second inclined portion 44 and the second recess 42. The R-machining is preferably performed on the entire circumference of edge 46. By applying the R-machining to edge 46, the gas generated at the electrode flows smoothly in the second recess 42, thus suppressing gas accumulation in the second recess 42. The radius of curvature of the edge 46 of the second recess 42 can be the same as or different from the radius of curvature of the edge 40 of the first recess 36.

[0078] The first and second protrusions 26 and 32 and the first and second recesses 36 and 42, as described above, can be formed by embossing. Similarly, the R-shaped processing of the bases 28 and 34 and the edges 40 and 46, as well as the first and second inclined portions 38 and 44, can also be formed by embossing.

[0079] The radius of curvature R1 of the base 34 of the second protrusion 32 in the second main surface 22, the radius of curvature R2 of the top 32a of the second protrusion 32, the radius of curvature R3 of the edge 46 of the second recess 42, and the radius of curvature R4 of the bottom 42a of the second recess 42 are defined in the same way as the radii of curvature R1 to R4 in the first main surface 20, and can be obtained using the same method as the method for obtaining the radii of curvature R1 to R4 in the first main surface 20.

[0080] (Separator support frame 10)

[0081] like Figure 1 and Figure 3 As shown, the annular partition wall support frame 10 has a first main surface 48 and a second main surface 50 opposite to the first main surface 48. The partition wall support frame 10 is disposed radially outside the circular partition wall 8. The inner peripheral edge of the partition wall support frame 10 and the outer peripheral edge of the partition wall 8 are mechanically joined using fasteners such as screws, bolts, and rivets, or joined by welding. Since there is no concern about fasteners falling off and sufficient joint strength is provided during long-term use, the inner peripheral edge of the partition wall support frame 10 and the outer peripheral edge of the partition wall 8 are preferably joined by welding. The material of the partition wall support frame 10 can be a conductive material (e.g., a metal material such as steel plate) or an insulating material (e.g., resin). When the partition wall support frame 10 is made of a metal material, the surface of the partition wall support frame 10 can be subjected to surface treatment such as nickel plating. In addition, a bracket (not shown) extending radially outward from the outer peripheral edge of the partition wall support frame 10 may also be attached to the partition wall support frame 10.

[0082] (Supply path of partition wall support frame 10)

[0083] A supply passage for supplying electrode liquid to the electrode chamber is formed in the partition wall support frame 10. Specifically, as shown in the figure... Figure 3 As shown, a first supply passage 52 for supplying anolyte to the anode chamber 16 and a second supply passage 54 for supplying catholyte to the cathode chamber 18 are formed in the partition wall support frame 10. The first supply passage 52 includes a first supply opening 56 penetrating the lower part of the partition wall support frame 10 and a first supply recess 58 extending radially inward from the first supply opening 56 on the first main surface 48 of the partition wall support frame 10. The second supply passage 54 includes a second supply opening 60 penetrating the lower part of the partition wall support frame 10 and a second supply recess 62 extending radially inward from the second supply opening 60 on the second main surface 50 of the partition wall support frame 10.

[0084] (Drainage passage of partition wall support frame 10)

[0085] Additionally, a discharge passage for discharging electrode liquid and gas from the electrode chamber is formed in the partition wall support frame 10. Specifically, as follows: Figure 3 As shown, a first discharge passage 64 for discharging anolyte and gas from the anode chamber 16 and a second discharge passage 66 for discharging catholyte and gas from the cathode chamber 18 are formed in the partition wall support frame 10. The first discharge passage 64 includes a first discharge opening 68 penetrating the upper part of the partition wall support frame 10 and a first discharge recess 70 extending radially inward from the first discharge opening 68 on the first main surface 48 of the partition wall support frame 10. The second discharge passage 66 includes a second discharge opening 72 penetrating the upper part of the partition wall support frame 10 and a second discharge recess 74 extending radially inward from the second discharge opening 72 on the second main surface 50 of the partition wall support frame 10.

[0086] (Electrode 12)

[0087] In this embodiment, electrode 12 is configured as an anode. For example... Figure 1 and Figure 2 As shown, electrode 12 is welded to the top 26a of the first protrusion 26 in the first main surface 20 of partition wall 8. This defines an anode chamber 16 between the first main surface 20 of partition wall 8 and electrode 12 (anode). Electrode 12 is formed as a single circular sheet from a perforated plate such as drawn metal mesh or perforated metal mesh, or a plain-woven metal mesh. The material of electrode 12 can be a conductive material (e.g., a metallic material such as nickel, or a metallic material obtained by nickel plating steel plates). Catalysts known for their ability to be appropriately attached to electrode 12 as catalysts for water electrolysis can be used.

[0088] (Current collector 14)

[0089] The current collector 14 is joined to the top 32a of the second protrusion 32 in the second main surface 22 of the partition wall 8 by welding. The current collector 14 is formed as a whole into a circular sheet by a perforated plate such as drawn metal mesh or perforated metal. The material of the current collector 14 can be a conductive material (e.g., a metal material such as steel plate). The surface of the current collector 14 can be subjected to surface treatment such as nickel plating.

[0090] In this invention, the method of joining the electrode or current collector to the top of the first or second protrusion is not limited to the aforementioned welding. Any method that ensures electrical conductivity between the partition wall and the electrode or current collector is acceptable. For example, threaded fixing or crimping by a stamping machine can also be used. From the viewpoint of reducing resistance and achieving excellent long-term stability, it is preferable that the electrode or current collector is joined to the top of at least one of the first and second protrusions by welding. More preferably, the electrode or current collector is joined to the top of both the first and second protrusions by welding.

[0091] (Cushioning material 76)

[0092] like Figure 1 and Figure 2 As shown, a buffer material 76 is provided on the side of the current collector 14 opposite to the joint surface that joins with the partition wall 8, for pressing the electrode 12 and the electrode 78 against the membrane 80 so that they are tightly attached to the membrane 80. The buffer material 76 is an elastic pad with woven wires, formed as a whole in a circular sheet shape. The material of the buffer material 76 can be a conductive material (e.g., a metal such as nickel).

[0093] (Electrode 78)

[0094] An electrode 78 is provided on the side of the buffer material 76 opposite to the contact surface of the current collector 14. In this embodiment, the electrode 78 is configured as a cathode. As described above, the current collector 14 is joined to the top 32a of the second protrusion 32, and the electrode 78 (cathode) contacts the current collector 14 through the buffer material 76, thus defining a cathode chamber 18 between the second main surface 22 of the partition wall 8 and the electrode 78. The electrode 78, like the electrode 12 described above, is formed into a circular sheet as a whole by a perforated plate or plain-woven metal mesh, such as drawn metal mesh or perforated metal mesh. The material of the electrode 78 can be a conductive material (e.g., a metal material such as nickel, or a metal material obtained by nickel plating steel plates). Catalysts known as nickel oxide, noble metal oxides, etc., can be appropriately attached to the electrode 78 as catalysts for water electrolysis.

[0095] In this embodiment, electrode 12 is the anode and electrode 78 is the cathode, but it is also possible to reverse this, with electrode 12 being the cathode and electrode 78 being the anode. In this case, the electrode chamber indicated by reference numeral 16 becomes the cathode chamber, and the electrode chamber indicated by reference numeral 18 becomes the anode chamber.

[0096] (Membrane Module 6)

[0097] Reference Figure 1 , Figure 2 and Figure 9 To illustrate, membrane module 6 includes a membrane 80, a membrane support frame 82 supporting the periphery of the membrane 80, and a gasket 84 sealing the anode chamber 16 and the cathode chamber 18. Furthermore, in Figure 9 For convenience, the description of washer 84 has been omitted.

[0098] (Membrane 80)

[0099] In the case of electrolysis of aqueous solutions of alkali metal oxides, membrane 80 is configured as an ion-permeable membrane (e.g., a diaphragm, an ion exchange membrane); in the case of electrolysis of aqueous solutions of alkali metal chlorides, membrane 80 is configured as an ion exchange membrane. Figure 9 As shown, the membrane 80 is also formed into a circular shape, just like the partition wall 8.

[0100] (Membrane support frame 82)

[0101] The membrane support frame 82 is formed in a ring shape corresponding to the partition wall support frame 10. The membrane support frame 82 is disposed radially outside the circular membrane 80, and is supported by clamping the outer periphery of the membrane 80 with its inner periphery. The membrane support frame 82 can be made of a conductive material (e.g., a metal such as steel plate) or an insulating material (e.g., resin, elastomer, etc.). When the membrane support frame 82 is made of a conductive material, a surface treatment such as nickel plating can be applied to the surface of the membrane support frame 82. Furthermore, a bracket (not shown) extending radially outward from the outer periphery of the membrane support frame 82 may also be attached to the membrane support frame 82.

[0102] like Figure 9As shown, first and second supply openings 86 and 88, penetrating the membrane support frame 82, are formed at the lower part of the membrane support frame 82. Additionally, first and second discharge openings 90 and 92, penetrating the membrane support frame 82, are formed at the upper part of the membrane support frame 82. The position of the first supply opening 86 of the membrane support frame 82 corresponds to the position of the first supply opening 56 of the partition wall support frame 10, and the position of the second supply opening 88 of the membrane support frame 82 corresponds to the position of the second supply opening 60 of the partition wall support frame 10. Furthermore, the position of the first discharge opening 90 of the membrane support frame 82 corresponds to the position of the first discharge opening 68 of the partition wall support frame 10, and the position of the second discharge opening 92 of the membrane support frame 82 corresponds to the position of the second discharge opening 72 of the partition wall support frame 10.

[0103] (Washer 84)

[0104] like Figure 1 and Figure 2 As shown, washers 84 are attached to both sides of the membrane support frame 82 in the X direction. Washers 84 can be adhered to the membrane support frame 82 using adhesive or double-sided tape. Washers 84 are formed as annular rings extending along the entire circumference of the membrane support frame 82. However, although detailed illustrations are omitted, washers 84 are not present at positions corresponding to the first and second supply openings 86, 88 and the first and second discharge openings 90, 92 of the membrane support frame 82. Furthermore, the material of washers 84 can be a suitable known material such as an elastomer.

[0105] Alternatively, the washer 84 can also serve as a membrane support frame 82. That is, the outer periphery of the membrane 80 can be clamped and supported by the inner periphery of the washer 84, which is formed into an annular shape corresponding to the partition wall support frame 10. In this case, the washer 84 functions as a membrane support frame 82, and is provided with the first and second supply openings 86 and 88 and the first and second discharge openings 90 and 92, similar to the membrane support frame 82 described above.

[0106] When assembling the electrolytic cell 2 as described above, multiple partition wall assemblies 4 and multiple membrane assemblies 6 are prepared and arranged alternately. At this time, the first and second supply openings 56 and 60 of the partition wall support frame 10 are aligned with the first and second supply openings 86 and 88 of the membrane support frame 82. Furthermore, the first and second discharge openings 68 and 72 of the partition wall support frame 10 are aligned with the first and second discharge openings 90 and 92 of the membrane support frame 82. Moreover, the electrode 78 is disposed on the side of the current collector 14 opposite to the mating surface with the partition wall 8, separated by a buffer material 76.

[0107] Next, multiple alternately arranged partition wall assemblies 4 and multiple membrane assemblies 6 are clamped and pressurized using a fixed head (not shown) and a movable head (not shown). Specifically, multiple tie rods (not shown) are used to connect the fixed head and the movable head, thereby clamping and pressurizing the alternately arranged partition wall assemblies 4 and membrane assemblies 6 using the fixed head and the movable head.

[0108] Although not shown in the figure, the flow path component for supplying anolyte, which communicates with the first supply opening 56 of the partition wall support frame 10 and the first supply opening 86 of the membrane support frame 82, the flow path component for supplying catholyte, which communicates with the second supply opening 60 of the partition wall support frame 10 and the second supply opening 88 of the membrane support frame 82, the flow path component for discharging anolyte, which communicates with the first discharge opening 68 of the partition wall support frame 10 and the first discharge opening 90 of the membrane support frame 82, and the flow path component for discharging catholyte, which communicates with the second discharge opening 72 of the partition wall support frame 10 and the second discharge opening 92 of the membrane support frame 82, are connected to the movable head and the fixed head.

[0109] (electrolysis)

[0110] During electrolysis in electrolytic cell 2, anolyte is first supplied to the anolyte supply flow path member from an anolyte pump (not shown), and catholyte is supplied to the catholyte supply flow path member from a catholyte pump (not shown). The pressure inside electrolytic cell 2 during electrolysis can be set to any value within the range of approximately 10 kPa to approximately 10 MPa. Since this allows for miniaturization of electrolytic cell 2 and improves electrolysis efficiency, the pressure inside electrolytic cell 2 during electrolysis is more preferably in the range of 300 kPa to 5 MPa.

[0111] The anolyte supplied to the flow path component for anolyte supply flows through the first supply opening 56 of the partition wall support frame 10 and the first supply opening 86 of the membrane support frame 82, and flows through the first supply recess 58 of the partition wall support frame 10 to be supplied to the anode chamber 16. Meanwhile, the catholyte supplied to the flow path component for catholyte supply flows through the second supply opening 60 of the partition wall support frame 10 and the second supply opening 88 of the membrane support frame 82, and flows through the second supply recess 62 of the partition wall support frame 10 to be supplied to the cathode chamber 18.

[0112] After anolyte is supplied to the anode chamber 16 and catholyte to the cathode chamber 18, the required voltage is applied to electrode 12 (anode in this embodiment) and electrode 78 (cathode in this embodiment). This generates gas from both electrodes 12 and 78. The gas generated by electrode 12, along with the anolyte, is discharged from the anode chamber 16 via the first discharge recess 70 of the partition wall support frame 10, and then flows through the first discharge opening 68 of the partition wall support frame 10 and the first discharge opening 90 of the membrane support frame 82 to the flow path member for anolyte discharge. Similarly, the gas generated by electrode 78, along with the catholyte, is discharged from the cathode chamber 18 via the second discharge recess 74 of the partition wall support frame 10, and then flows through the second discharge opening 72 of the partition wall support frame 10 and the second discharge opening 92 of the membrane support frame 82 to the flow path member for catholyte discharge.

[0113] As described above, in this embodiment, the edges 40 and 46 of the first and second recesses 36 and 42 are R-processed, so that the gas generated by electrode 12 flows in a manner that does not stagnate inside the first recess 36, and the gas generated by electrode 78 flows in a manner that does not stagnate inside the second recess 42. As a result, gas accumulation inside the first and second recesses 36 and 42 can be suppressed. Therefore, the flow of electrode liquid inside the electrode chambers (anode chamber 16 and cathode chamber 18) is homogenized, so the concentration difference of electrode liquid inside the electrode chambers does not become excessively large. As a result, the current distribution is homogenized, thus preventing a decrease in electrolysis efficiency.

[0114] Furthermore, when the bases 28 and 34 of the first and second protrusions 26 and 32 are also R-processed as in this embodiment, the accumulation of gas near the first and second protrusions 26 and 32 can be suppressed. Therefore, the flow of electrode liquid in the electrode chamber can be further homogenized.

[0115] When the electrolytic cell 2 is stopped, the gas dissolved in the electrode liquid is released, which may reduce the purity of the gas generated by electrolysis. Therefore, when the electrolytic cell 2 stops operating, it is preferable to quickly replace or discharge the electrode liquid in the electrode chamber. In particular, in high-pressure electrolytic cells (e.g., electrolytic cells operating at a pressure of 300 kPa to 5 MPa) where the operating pressure of the electrolytic cell 2 is relatively high, the amount of dissolved gas in the electrode liquid is relatively large, so it is necessary to quickly replace or discharge the electrode liquid in the electrode chamber. In this regard, in the electrolytic cell 2 of this embodiment, the edges 40 and 46 of the first and second recesses 36 and 42 are R-machined, thereby reducing the retention of electrode liquid in the first and second recesses 36 and 42. Therefore, the electrode liquid in the electrode chamber can be quickly replaced or discharged, and the decrease in the purity of the gas generated by electrolysis can be suppressed.

[0116] (First variation)

[0117] Regarding the first and second protrusions 26 and 32 and the first and second recesses 36 and 42, the above embodiments have described an example of a hemispherical shape, but they are not limited to hemispherical shapes and may be other shapes. For example, as shown in Figures 10(a) and 10(b), the first and second protrusions 26 and 32 and the first and second recesses 36 and 42 may also be conical. The tops 26a and 32a of the first and second protrusions 26 and 32 may also have rounded corners. The bottoms 36a and 42a of the first and second recesses 36 and 42 may also have rounded corners. The diameter of the first protrusion 26 and the first recess 36 gradually decreases as it moves away from the first flat portion 24. In addition, the diameter of the second protrusion 32 and the second recess 42 gradually decreases as it moves away from the second flat portion 30.

[0118] In the first modified example, the radii of curvature of the tops 26a and 32a of the first and second protrusions 26 and 32 can be approximately 3 mm to 200 mm, but more preferably 3 mm or more and 200 mm or less, and more preferably 5 mm or more and 50 mm or less. The radii of curvature of the bottoms 36a and 42a of the first and second recesses 36 and 42 can be approximately 1 mm to 190 mm, but more preferably 1 mm or more and 190 mm or less, more preferably 2 mm or more and 50 mm or less, and even more preferably 3 mm or more and 20 mm or less. In the first modified example, the height H of the first and second protrusions 26 and 32 and the depth D of the first and second recesses 36 and 42 can be approximately 3 mm or more and 20 mm or less, more preferably 5 mm or more and 15 mm or less, and even more preferably 7 mm or more and 10 mm or less.

[0119] In the first modified example, the edges 40 and 46 of the first and second recesses 36 and 42 are also R-machined. When the radius of curvature of the edge 40 of the first recess 36 is set to R7 and the radius of curvature of the bottom 36a of the first recess 36 is set to R8, the ratio of the radii of curvature R8 / R7 is preferably 0.05 or more and 190 or less, more preferably 0.2 or more and 17 or less, and even more preferably 0.3 or more and 7 or less. Moreover, the base 28 of the first protrusion 26 may also be R-machined. For example, when the radius of curvature of the base 28 of the first protrusion 26 is set to R5 and the radius of curvature of the top 26a of the first protrusion 26 is set to R6, the ratio of the radii of curvature R6 / R5 is preferably 0.6 or more and 400 or less.

[0120] The radius of curvature R5 of the base 28 of the first protrusion 26 can be, for example, 0.5 mm or more and 5 mm or less, but preferably 0.7 mm or more and 3 mm or less. Additionally, the radius of curvature R7 of the edge 40 of the first recess 36 can be, for example, 1 mm or more and 20 mm or less, but preferably 3 mm or more and 10 mm or less. In the examples shown in Figures 10(a) and 10(b), the dimensions of the second protrusion 32 (including the radius of curvature of the top 32a and the base 34) are the same as the dimensions of the first protrusion 26, and the dimensions of the second recess 42 (including the radius of curvature of the bottom 42a and the edge 46) are the same as the dimensions of the first recess 36, but they can also be different.

[0121] In the first variation, the radii of curvature R5 to R8 correspond to the aforementioned radii of curvature R1 to R4, and are defined in the same way as the radii of curvature R1 to R4. They can be obtained using the same method as the method for obtaining the radii of curvature R1 to R4.

[0122] In the first modified example described above, the gas generated by electrode 12 flows in a manner that does not stagnate inside the first recess 36, and the gas generated by electrode 78 flows in a manner that does not stagnate inside the second recess 42. Therefore, it is also possible to suppress the accumulation of gas inside the first and second recesses 36 and 42. Furthermore, when the bases 28 and 34 of the first and second protrusions 26 and 32 are also R-machined, the gas generated by electrode 12 flows in a manner that does not accumulate near the first protrusion 26, and the gas generated by electrode 78 flows in a manner that does not accumulate near the second protrusion 32. Therefore, it is possible to further suppress the accumulation of gas near the first and second protrusions 26 and 32.

[0123] Furthermore, in the first variation, the first recess 36 and the first protrusion 26 may be connected via the first flat portion 24, and the second recess 42 and the second protrusion 32 may be connected via the second flat portion 30 (see Figure 10(a)). Alternatively, as shown in Figure 10(b), a first inclined portion 38 may be provided between the first recess 36 and the first protrusion 26, and a second inclined portion 44 may be provided between the second recess 42 and the second protrusion 32.

[0124] (Second variation)

[0125] As shown in Figures 11(a) and 11(b), the first and second protrusions 26 and 32 and the first and second recesses 36 and 42 can also be frustoconical in shape. The diameter of the first protrusion 26 and the first recess 36 gradually decreases as they move away from the first flat portion 24. The diameter of the second protrusion 32 and the second recess 42 gradually decreases as they move away from the second flat portion 30. In the second modified example, the height H of the first and second protrusions 26 and 32 and the depth D of the first and second recesses 36 and 42 can be, for example, 3 mm or more and 20 mm or less, more preferably 5 mm or more and 15 mm or less, and even more preferably 7 mm or more and 10 mm or less.

[0126] In the second variation, the tops 26a and 32a of the first and second protrusions 26 and 32 are circular or approximately circular when viewed from a direction perpendicular to the first main surface 20 and the second main surface 22, respectively. As shown in Figures 11(a) and 11(b), the diameter d1 of the tops 26a and 32a of the first and second protrusions 26 and 32 is the diameter of the portion parallel or approximately parallel to the first flat portion 24 of the first main surface 20 (excluding the portion that has undergone R-machining), and is smaller than the diameter d of the first and second recesses 36 and 42. In the second variation, electrodes or current collectors are also welded to the tops 26a and 32a of the first and second protrusions 26 and 32, through which current flows during electrolysis. From the viewpoint of reducing resistance and improving electrolysis efficiency, the diameter d1 of the tops 26a and 32a of the first and second protrusions 26 and 32 is preferably 5 mm or more, more preferably 10 mm or more, and even more preferably 15 mm or more. In the second modification, the joining of the electrode or current collector to the tops 26a and 32a of the first and second protrusions 26 and 32 can also be achieved using methods other than welding.

[0127] In the second modification, the edges 40 and 46 of the first and second recesses 36 and 42 are also rounded. Furthermore, the bases 28 and 34 of the first and second protrusions 26 and 32 may also be rounded. Additionally, in the second modification, it is preferable that the top peripheries 26b and 32b of the first and second protrusions 26 and 32 are also rounded, as are the bottom peripheries 36b and 42b of the first and second recesses 36 and 42.

[0128] When the radius of curvature of the base 28 of the first protrusion 26 is set to R9 and the radius of curvature of the top periphery 26b of the first protrusion 26 is set to R10, the ratio of the radii of curvature R10 / R9 is preferably 0.1 or more and 100 or less, more preferably 0.4 or more and 40 or less. Furthermore, when the radius of curvature of the edge 40 of the first recess 36 is set to R11 and the radius of curvature of the bottom periphery 36b of the first recess 36 is set to R12, the ratio of the radii of curvature R12 / R11 is preferably 0.05 or more and 50 or less, more preferably 0.1 or more and 10 or less, and even more preferably 0.2 or more and 5 or less.

[0129] The radius of curvature R9 of the base 28 of the first protrusion 26 can be, for example, 0.5 mm or more and 5 mm or less, and the radius of curvature R11 of the edge 40 of the first recess 36 can be, for example, 1 mm or more and 20 mm or less, but preferably 3 mm or more and 15 mm or less. Furthermore, the radius of curvature R10 of the top periphery 26b of the first protrusion 26 can be, for example, 0.5 mm or more and 50 mm or less, but preferably 2 mm or more and 20 mm or less. The radius of curvature R12 of the bottom periphery 36b of the first recess 36 can be, for example, 1 mm or more and 50 mm or less, but preferably 2 mm or more and 20 mm or less, and more preferably 3 mm or more and 10 mm or less. In the examples shown in Figures 11(a) and 11(b), the dimensions of the second protrusion 32 (including the radius of curvature of the top periphery 32b and the base 34) are the same as those of the first protrusion 26, and the dimensions of the second recess 42 (including the radius of curvature of the bottom periphery 42b and the edge 46) are the same as those of the first recess 36, but they can also be different.

[0130] In the second variation, the radius of curvature R9 of the base 28 of the first protrusion 26 and the radius of curvature R9 of the base 34 of the second protrusion 32 are defined in the same way as the radius of curvature R1 described above, and can be obtained using the same method as that used to obtain the radius of curvature R1. Furthermore, in the second variation, the radius of curvature R11 of the edge 40 of the first recess 36 and the radius of curvature R11 of the edge 46 of the second recess 42 are defined in the same way as the radius of curvature R3 described above, and can be obtained using the same method as that used to obtain the radius of curvature R3.

[0131] Reference Figure 12The radius of curvature R10 of the top periphery 26b of the first protrusion 26 in the second modification example will be explained. The intersection point of the straight line L8 extending along the top 26a of the first protrusion 26 and the tangent L9 of the first protrusion 26 passing through the top periphery 26b is defined as P3. An auxiliary line L10 is defined that passes through the intersection point P3 and bisects the angle θ3 formed by the straight line L8 and the tangent L9. An imaginary circle C5 with a center O5 is assumed to exist on the auxiliary line L10. Furthermore, the radius of curvature R10 of the imaginary circle C5 when its circumference passes through the intersection point Q3 of the top periphery 26b of the first protrusion 26 and the auxiliary line L10, and when the circumference of the imaginary circle C5 is tangent to both the straight line L8 and the tangent L9, is defined as the radius of curvature R10 in this invention.

[0132] Reference Figure 13 The radius of curvature R12 of the bottom periphery 36b of the first recess 36 in the second modification example will be explained. The intersection point of the straight line L11 extending along the bottom 36a of the first recess 36 and the tangent L12 of the first recess 36 passing through the bottom periphery 36b is defined as P4. An auxiliary line L13 is defined that passes through the intersection point P4 and bisects the angle θ4 formed by the straight line L11 and the tangent L12. An imaginary circle C6 with a center O6 is assumed to exist on the auxiliary line L13. Furthermore, the radius of curvature R12 of the imaginary circle C6 when its circumference passes through the intersection point Q4 of the bottom periphery 36b of the first recess 36 and the auxiliary line L13, and when its circumference is tangent to both the straight line L11 and the tangent L12, is defined as the radius of curvature R12 in this invention.

[0133] In the second modification described above, the gas generated by electrode 12 flows in a manner that does not stagnate inside the first recess 36, and the gas generated by electrode 78 flows in a manner that does not stagnate inside the second recess 42. Therefore, it is also possible to suppress the accumulation of gas inside the first and second recesses 36 and 42. Furthermore, when the bases 28 and 34 of the first and second protrusions 26 and 32 are also R-machined, the gas generated by electrode 12 flows in a manner that does not accumulate near the first protrusion 26, and the gas generated by electrode 78 flows in a manner that does not accumulate near the second protrusion 32. Therefore, it is possible to further suppress the accumulation of gas near the first and second protrusions 26 and 32.

[0134] Furthermore, in the second modification, the first and second protrusions 26 and 32 are frustum-shaped, thus the contact area between the first protrusion 26 and the electrode 12 and the contact area between the second protrusion 32 and the current collector 14 are larger than those in the above-described embodiment and the first modification. Therefore, the resistance during electrolysis is reduced, thereby improving the electrolysis efficiency.

[0135] Furthermore, in the second variation, the first recess 36 and the first protrusion 26 may be connected via the first flat portion 24, and the second recess 42 and the second protrusion 32 may be connected via the second flat portion 30 (see Figure 11(a)). Alternatively, as shown in Figure 11(b), a first inclined portion 38 may be provided between the first recess 36 and the first protrusion 26, and a second inclined portion 44 may be provided between the second recess 42 and the second protrusion 32.

Claims

1. A partition wall for an electrolytic cell, dividing an anode chamber and a cathode chamber, characterized in that, The partition wall of the electrolytic cell has a first main surface and a second main surface located on the side opposite to the first main surface. The first main surface includes a first flat portion and a plurality of first recesses that are recessed from the first flat portion. The edges of the first recesses are rounded. The second main surface includes a second flat portion and a plurality of second recesses that are recessed from the second flat portion, and the edges of the second recesses are R-machined.

2. The partition wall of the electrolytic cell according to claim 1, characterized in that, The first main surface includes a plurality of first protrusions in a mountain shape that protrude beyond the first flat portion. The second main surface includes a plurality of second protrusions in a mountain shape that protrude beyond the second flat portion.

3. The partition wall of the electrolytic cell according to claim 2, characterized in that, A first inclined portion, which is inclined relative to the first flat portion, is provided between the first protrusion and the first recess on the first main surface. A second inclined portion is provided between the second protrusion and the second recess on the second main surface, which is inclined relative to the second flat portion.

4. The partition wall of the electrolytic cell according to claim 2, characterized in that, The positions of the plurality of first recesses correspond to the positions of the plurality of second protrusions. The positions of the plurality of second depressions correspond to the positions of the plurality of first protrusions.

5. The partition wall of the electrolytic cell according to claim 2, characterized in that, The first protrusion, the second protrusion, the first depression, and the second depression are hemispherical.

6. The partition wall of the electrolytic cell according to claim 5, characterized in that, When the radius of curvature of the edge of the first recess and the edge of the second recess is set to R3, and the radius of curvature of the bottom of the first recess and the bottom of the second recess is set to R4, the ratio of the radii of curvature R4 / R3 is 0.1 or more and 19 or less.

7. The partition wall of the electrolytic cell according to claim 5, characterized in that, The base of the first protrusion and the base of the second protrusion were subjected to R machining.

8. The partition wall of the electrolytic cell according to claim 7, characterized in that, When the radius of curvature of the base of the first protrusion and the base of the second protrusion is set to R1, and the radius of curvature of the top of the first protrusion and the top of the second protrusion is set to R2, the ratio of the radii of curvature R2 / R1 is 0.6 or more and 40 or less. When the radius of curvature of the edge of the first recess and the edge of the second recess is set to R3, and the radius of curvature of the bottom of the first recess and the bottom of the second recess is set to R4, the ratio of the radii of curvature R4 / R3 is 0.1 or more and 19 or less.

9. The partition wall of the electrolytic cell according to claim 2, characterized in that, The first protrusion, the second protrusion, the first recess, and the second recess are conical in shape, and the top of the first protrusion and the top of the second protrusion, as well as the bottom of the first recess and the bottom of the second recess, have rounded corners.

10. The partition wall of the electrolytic cell according to claim 9, characterized in that, When the radius of curvature of the edge of the first recess and the edge of the second recess is set to R7, and the radius of curvature of the bottom of the first recess and the bottom of the second recess is set to R8, the ratio of the radii of curvature R8 / R7 is 0.05 or more and 190 or less.

11. The partition wall of the electrolytic cell according to claim 9, characterized in that, The base of the first protrusion and the base of the second protrusion were subjected to R machining.

12. The partition wall of the electrolytic cell according to claim 11, characterized in that, When the radius of curvature of the base of the first protrusion and the base of the second protrusion is set to R5, and the radius of curvature of the top of the first protrusion and the top of the second protrusion is set to R6, the ratio of the radii of curvature R6 / R5 is 0.6 or more and 400 or less. When the radius of curvature of the edge of the first recess and the edge of the second recess is set to R7, and the radius of curvature of the bottom of the first recess and the bottom of the second recess is set to R8, the ratio of the radii of curvature R8 / R7 is 0.05 or more and 190 or less.

13. The partition wall of the electrolytic cell according to claim 2, characterized in that, The first protrusion, the second protrusion, the first recess, and the second recess are in the shape of a frustum, and the bottom periphery of the first recess and the bottom periphery of the second recess are subjected to R-machining.

14. The partition wall of the electrolytic cell according to claim 13, characterized in that, When the radius of curvature of the edge of the first recess and the edge of the second recess is set to R11, and the radius of curvature of the bottom periphery of the first recess and the bottom periphery of the second recess is set to R12, the ratio of the radii of curvature R12 / R11 is 0.05 or more and 50 or less.

15. The partition wall of the electrolytic cell according to claim 13, characterized in that, The base of the first protrusion and the base of the second protrusion, as well as the top periphery of the first protrusion and the top periphery of the second protrusion, were subjected to R machining.

16. The partition wall of the electrolytic cell according to claim 15, characterized in that, When the radius of curvature of the base of the first protrusion and the base of the second protrusion is set to R9, and the radius of curvature of the top periphery of the first protrusion and the top periphery of the second protrusion is set to R10, the ratio of the radii of curvature R10 / R9 is 0.1 or more and 100 or less. When the radius of curvature of the edge of the first recess and the edge of the second recess is set to R11, and the radius of curvature of the bottom periphery of the first recess and the bottom periphery of the second recess is set to R12, the ratio of the radii of curvature R12 / R11 is 0.05 or more and 50 or less.

17. A partition wall assembly, characterized in that, The partition wall assembly includes a partition wall as described in any one of claims 1 to 16 and a partition wall support frame that supports the periphery of the partition wall.

18. The partition wall assembly according to claim 17, characterized in that, The partition wall is circular in shape, and the partition wall support frame is annular.

19. The partition wall assembly according to claim 17, characterized in that, The partition wall assembly includes an electrode or current collector engaged at the top of each of the plurality of first protrusions and a current collector or electrode engaged at the top of each of the plurality of second protrusions.

20. The partition wall assembly according to claim 17, characterized in that, The partition wall assembly includes electrodes or current collectors joined to the top of each of the plurality of first protrusions by welding and current collectors or electrodes joined to the top of each of the plurality of second protrusions.

21. The partition wall assembly according to claim 17, characterized in that, The partition wall assembly includes electrodes or current collectors joined by welding to the tops of the plurality of first protrusions and current collectors or electrodes joined by welding to the tops of the plurality of second protrusions.

22. An electrolytic cell having alternately arranged a plurality of partition wall assemblies as described in claim 19 and a plurality of membrane assemblies, characterized in that, The membrane assembly includes a membrane and a membrane support frame that supports the periphery of the membrane.

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