Diaphragm for alkaline water electrolysis, method for producing same, and alkaline water electrolyzer

Abstract

To improve the physical strength of a porous diaphragm for alkaline water electrolysis.SOLUTION: A diaphragm for alkaline water electrolysis separating an anode chamber and a cathode chamber of an alkaline water electrolyzer includes a polymer porous membrane integrally having a seal region sandwiched between tank constituent members in the alkaline water electrolyzer and a separator region disposed on an inner peripheral side of the seal region. The separator region has a reinforcing portion of a bulk structure SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a diaphragm for alkaline water electrolysis and an alkaline water electrolytic cell including the same. [Background technology]

[0002] In recent years, hydrogen has been attracting attention as an environmentally friendly, clean energy source because it does not produce CO2 during combustion or reaction. Alkaline water electrolysis is a well-known method for producing hydrogen. Alkaline water electrolysis generates hydrogen and oxygen by electrolyzing water using an alkaline aqueous solution as the electrolyte.

[0003] A known electrolytic cell used in alkaline water electrolysis has a structure in which a porous diaphragm is placed between an anode chamber and a cathode chamber. Oxygen is produced in the anode chamber of the electrolytic cell, and hydrogen is produced in the cathode chamber. The diaphragm is required to have gas barrier properties to prevent the permeation of oxygen gas and hydrogen gas so that these gases do not mix.

[0004] Because the diaphragm is a thin sheet with a porous structure made of an organic polymer, it may be subject to physical damage such as breakage. If the diaphragm is physically damaged, the gas barrier properties of the diaphragm will decrease, requiring immediate maintenance. Therefore, the diaphragm for alkaline water electrolysis described in Patent Document 1 includes a sheet-like porous support and a microporous membrane containing an organic polymer resin laminated on one or both sides of the porous support, and is designed to maintain gas barrier properties even if physical damage occurs to the membrane surface (i.e., the microporous membrane). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-204146 Summary of the Invention [Problem to be solved by the invention]

[0006] For more economical hydrogen production, the size of alkaline water electrolyzers is required to be increased. 2 In the above cases, the area of ​​the diaphragm naturally becomes larger, and the diaphragm is required to have strength that allows it to be handled during construction of the electrolytic cell and to withstand its own weight. Furthermore, in zero-gap electrolytic cells with high electrolysis efficiency, the diaphragm, which is in contact with the electrode, vibrates due to the gas generated on the electrode surface, and therefore the diaphragm is required to have strength that allows it to withstand vibration.

[0007] The present disclosure has been made in light of the above circumstances, and an object of the present disclosure is to provide a technique for improving the physical strength of a diaphragm for alkaline water electrolysis having a porous structure. [Means for solving the problem]

[0008] In order to solve the above problems, a diaphragm for alkaline water electrolysis according to one embodiment of the present disclosure comprises: A diaphragm for alkaline water electrolysis separating an anode chamber and a cathode chamber of an alkaline water electrolytic cell, comprising: a porous polymer membrane integrally having a seal region that is sandwiched between tank-constituting members in the alkaline water electrolytic tank and a separator region that is disposed on the inner circumferential side of the seal region, The separator region has a bulk structural reinforcement.

[0009] An alkaline water electrolytic cell according to one embodiment of the present disclosure includes: an anode chamber frame that defines an anode chamber; a cathode chamber frame defining the cathode chamber; an anode housed in the anode chamber; a cathode accommodated in the cathode chamber; the alkaline water electrolysis diaphragm disposed between the anode chamber frame and the cathode chamber frame to separate the anode chamber from the cathode chamber.

[0010] A method for producing a diaphragm for alkaline water electrolysis according to one embodiment of the present disclosure includes: A method for manufacturing a diaphragm for alkaline water electrolysis separating an anode chamber and a cathode chamber of an alkaline water electrolytic cell, comprising: preparing a porous polymer membrane integrally having a seal region to be sandwiched between cell-constituting members in the alkaline water electrolytic cell and a separator region disposed on the inner circumferential side of the seal region; and forming a bulk structural reinforcing portion in the separator region of the porous polymer membrane by compression bonding or welding. [Effects of the Invention]

[0011] The present disclosure provides a technique for improving the physical strength of a diaphragm for alkaline water electrolysis having a porous structure. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view showing the overall configuration of an alkaline water electrolytic cell according to one embodiment of the present disclosure. [Figure 2] FIG. 2 is a partially enlarged cross-sectional view of the alkaline water electrolytic cell for providing a detailed explanation of the support structure for the alkaline water electrolysis diaphragm on the cell body. [Figure 3] FIG. 3 is a development view of a diaphragm for alkaline water electrolysis. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV of the diaphragm for alkaline water electrolysis shown in FIG. 3 . [Figure 5] FIG. 5 is a cross-sectional view taken along line IV-IV of the diaphragm for alkaline water electrolysis shown in FIG. 3 , which is a modification of the embodiment. [Figure 6] FIG. 6 is a development view of a diaphragm for alkaline water electrolysis having a reinforcing portion according to Modification 1. [Figure 7] FIG. 7 is a development view of a diaphragm for alkaline water electrolysis having a reinforcing portion according to Modification 2. [Figure 8] FIG. 8 is a development view of a diaphragm for alkaline water electrolysis having a reinforcing portion according to Modification 3. [Figure 9] FIG. 9 is a development view of a diaphragm for alkaline water electrolysis having a reinforcing portion according to Modification 4. DETAILED DESCRIPTION OF THE INVENTION

[0013] Next, embodiments of the present disclosure will be described with reference to the drawings. First, a schematic configuration of an alkaline water electrolytic cell (hereinafter simply referred to as "electrolytic cell 1") to which a diaphragm for alkaline water electrolysis according to the present disclosure (hereinafter simply referred to as "diaphragm 4") is applied will be described.

[0014] [Schematic configuration of electrolytic cell 1] FIG. 1 is a cross-sectional view showing a schematic configuration of an electrolytic cell 1 according to an embodiment of the present disclosure. The electrolytic cell 1 shown in FIG. 1 includes a cell body 2. The interior of the cell body 2 is separated by a diaphragm 4 into an anode chamber 48 and a cathode chamber 49. The anode chamber 48 and the cathode chamber 49 each have an electrolyte supply port and an outlet port for the alkaline solution and gas (hydrogen or oxygen) after electrolysis. An anode assembly 3 is disposed on the anode chamber 48 side of the diaphragm 4 in the electrolytic cell 1. The anode assembly 3 includes a mesh anode 31 facing the diaphragm 4, an anode conductor plate 32 provided integrally with the anode 31 around the anode 31, and a connection terminal 33 disposed on the anode conductor plate 32. A cathode assembly 7 is disposed on the cathode chamber 49 side of the diaphragm 4 in the electrolytic cell 1. The cathode assembly 7 includes a mesh-like cathode 71 facing the diaphragm 4, a cathode conductor plate 72 arranged away from the cathode 71 on the side opposite the diaphragm 4, a connection terminal 73 provided on the cathode conductor plate 72, and a conductive elastic body 74 provided between the cathode 71 and the cathode conductor plate 72. The elastic body 74 presses the cathode 71 against the diaphragm 4, bringing the anode 31 and the diaphragm 4, and the diaphragm 4 and the cathode 71 into close contact with each other.

[0015] The anode 31 is a known electrode that has been used as an anode for alkaline water electrolysis. Known examples of such anodes 31 include those that include a conductive substrate and a catalytic layer coating the surface of the substrate. Examples of the substrate for the anode 31 include nickel, nickel-based alloys, stainless steel, iron, and nickel-coated iron. Examples of the catalytic layer for the anode 31 include nickel-containing materials such as nickel oxide, metallic nickel, nickel hydroxide, and nickel-cobalt oxide. The cathode 71 is a known electrode that has been used as a cathode for alkaline water electrolysis. Known examples of such cathodes 71 include those that include a conductive substrate and a catalytic layer coating the surface of the substrate. Examples of the conductive substrate for the cathode 71 include nickel, nickel-based alloys, stainless steel, iron, and nickel-coated iron. Examples of the catalytic layer for the cathode 71 include precious metal oxides, nickel, cobalt, molybdenum, manganese, and oxides thereof.

[0016] When alkaline water is electrolyzed in the electrolytic cell 1 configured as described above, the anode chamber 48 and the cathode chamber 49 are filled with an electrolyte, and a voltage is applied between the anode 31 and the cathode 71. An alkaline solution such as potassium hydroxide or sodium hydroxide is used as the electrolyte. The concentration of the alkaline solution is not particularly limited, but is preferably about 25-35% by mass. The temperature of the electrolyte is also not particularly limited, but is preferably about 80-100°C. In the cathode chamber 49, electrons are supplied, causing electrolysis of the water in the electrolyte, generating hydrogen gas and hydroxide ions. The hydroxide ions in the cathode chamber 49 permeate the diaphragm 4 and move to the anode chamber 48. In the anode chamber 48, oxygen gas and water are generated from the hydroxide ions.

[0017] [Diaphragm 4] Here, a detailed description will be given of the diaphragm 4 and the support structure for the diaphragm 4. Figure 2 is an enlarged partial cross-sectional view of the electrolytic cell 1 for a detailed description of the support structure for the diaphragm 4 on the cell body 2.

[0018] 1 and 2, the cell body 2 of the electrolytic cell 1 is formed by combining an anode chamber frame 21 that defines the anode chamber 48 and a cathode chamber frame 22 that defines the cathode chamber 49. The anode chamber frame 21 and the cathode chamber frame 22 have frame surfaces 21a and 22a that face each other with a diaphragm 4 or the like disposed therebetween. The frame surface 21a of the anode chamber frame 21 and the frame surface 22a of the cathode chamber frame 22 have substantially the same shape; for example, the frame surfaces 21a and 22a are rectangular or circular strips.

[0019] The anode assembly 3, the diaphragm 4, and the cathode assembly 7 are sandwiched between the frame surface 21a of the anode chamber frame 21 and the frame surface 22a of the cathode chamber frame 22. More specifically, the gasket 24, the anode conductor plate 32 of the anode assembly 3, the diaphragm 4, the spacer 23, the gasket 25, the cathode conductor plate 72 of the cathode assembly 7, and the gasket 26 are arranged in this order between the frame surface 21a of the anode chamber frame 21 and the frame surface 22a of the cathode chamber frame 22.

[0020] The gasket 24 is a sealing material that provides a liquid-tight seal between the anode chamber frame 21 and the anode conductor plate 32. The gasket 25 is a sealing material that provides a liquid-tight seal between the spacer 23 and the cathode conductor plate 72. The gasket 26 is a sealing material that provides a liquid-tight seal between the cathode conductor plate 72 and the cathode chamber frame 22. The gaskets 24, 25, and 26 can be made of materials such as ethylene-propylene-diene rubber (EPDM) and vulcanized or peroxide-crosslinked ethylene-propylene rubber (EPM).

[0021] The spacer 23 separates the diaphragm 4 from the cathode 71. The spacer 23 also cooperates with the anode conductor plate 32 to sandwich the diaphragm 4 in the thickness direction. The diaphragm 4 is pressed in the thickness direction from both sides by the anode conductor plate 32 and the spacer 23. The diaphragm 4 is larger than the spacer 23 and protrudes outside the vessel.

[0022] FIG. 3 is a development view of the diaphragm 4, and FIGS. 4 and 5 are cross-sectional views of the diaphragm 4 shown in FIG. 3 taken along line IV-IV. The diaphragm 4 shown in FIGS. 4 and 5 is in a state before being clamped by the anode chamber frame 21 and the cathode chamber frame 22. As shown in FIG. 3, the diaphragm 4 comprises a porous polymer membrane 40 integrally having a seal region 41 sandwiched between cell components of the electrolytic cell 1 (specifically, the anode conductor plate 32 and the spacer 23), a marginal region 44 disposed on the outer periphery of the seal region 41, and a separator region 43 disposed on the inner periphery of the seal region 41. The marginal region 44 is a strip-shaped region along the outer edge of the diaphragm 4 and is the portion of the diaphragm 4 exposed to the outside of the cell. The inner peripheral edge of the marginal region 44 corresponds to the outer peripheral edge of the seal region 41. The seal region 41 has substantially the same shape as the frame surface 21a of the anode chamber frame 21 and the frame surface 22a of the cathode chamber frame 22. The inner peripheral edge of the seal region 41 corresponds to the outer peripheral edge of the separator region 43. The separator region 43 is a portion of the diaphragm 4 that is exposed to the inside of the cell and functions as a partition wall that separates the anode chamber 48 and the cathode chamber 49. Although the diaphragm 4 shown in FIG. 3 is rectangular, the diaphragm 4 is not limited to a rectangular shape and may have any shape that corresponds to the shapes of the anode chamber frame 21 and the cathode chamber frame 22. For example, if the anode chamber frame 21 and the cathode chamber frame 22 are annular, the diaphragm 4 may be circular.

[0023] As shown in Figures 3 and 4, the membrane 4 comprises a porous polymer membrane 40 made of an organic polymer resin and having numerous pores throughout the entire membrane (excluding reinforcing sections 45, which will be described later). Alternatively, as shown in Figures 3 and 5, the membrane 4 comprises a porous polymer membrane 40 made of an organic polymer resin and having numerous pores throughout the entire membrane (excluding reinforcing sections 45, which will be described later), and a sheet-like porous support 50 that supports the porous polymer membrane 40. The support 50 may be disposed inside the porous polymer membrane 40 or on one surface of the porous polymer membrane 40. The organic polymer resin is impregnated into part or all of the support 50.

[0024] The organic polymer resin constituting the porous polymer membrane 40 is at least one selected from the group consisting of polysulfone, polyethersulfone, polyphenylsulfone, polyvinylidene fluoride, polycarbonate, polytetrafluoroethylene, polypropylene, polyphenylene sulfide, polyketone, polyetheretherketone, polyimide, and polyetherimide. Inorganic particles may be added to the porous polymer membrane 40. The inclusion of inorganic molecules in the membrane 4 makes the membrane 4 hydrophilic, thereby suppressing adhesion of oxygen gas and hydrogen gas bubbles to the membrane surface. Examples of inorganic particles include metal hydroxides or oxides of magnesium, zirconium, titanium, zinc, aluminum, tantalum, etc.; sulfates of calcium, barium, lead, strontium, etc.; nitrides of titanium, zirconium, hafnium, etc.; and carbides of titanium, zirconium, hafnium, etc. The support 50 is a nonwoven fabric, a woven fabric, or a composite fabric of a nonwoven fabric and a woven fabric. The support 50 is formed of at least one type of fiber selected from the group consisting of polyphenylene sulfide, polypropylene, polysulfone, polyethersulfone, polyphenylsulfone, fluorine-based resin, polyketone, polyimide, and polyetherimide.

[0025] As shown in FIGS. 3 to 5 , the diaphragm 4 has reinforcing portions 45 across the entire separator region 43. In the example shown in FIG. 3 , the reinforcing portions 45 of the diaphragm 4 are linear and extend vertically in the separator region 43. The linear reinforcing portions 45 extending vertically are arranged at approximately equal intervals in the horizontal direction. As shown in FIG. 6 , the reinforcing portions 45 of the diaphragm 4 may extend from the separator region 43 to the seal region 41. Note that in the examples shown in FIGS. 3 and 6 , the reinforcing portions 45 of the diaphragm 4 are provided across the entire separator region 43, but the reinforcing portions 45 may be provided partially in locations where reinforcement is particularly required. For example, the reinforcing portions 45 may be provided partially in areas that come into contact with the electrodes 31, 71 and are vibrated by generated bubbles, or in peripheral areas that are subjected to loads during assembly of the electrolytic cell 1.

[0026] The reinforcing portion 45 of the separator region 43 has a bulk structure, while the portion excluding the reinforcing portion 45 has a porous structure. Here, a porous structure is a structure with a high porosity having numerous pores, whereas a "bulk structure" is a structure with a low porosity having almost no or no voids such as pores. The bulk structure of the present disclosure may include a non-porous structure having no voids such as pores, or a porous structure having pores but an extremely low porosity compared to the portion of the separator region 43 excluding the reinforcing portion 45. The reinforcing portion 45 having such a bulk structure has a lower porosity, a higher density, and a denser structure compared to the portion of the separator region 43 excluding the reinforcing portion 45 (i.e., the portion of the porous structure).

[0027] In the diaphragm 4 according to this embodiment, the numerous pores that existed in the region corresponding to the reinforcing portion 45 of the polymer porous membrane 40 (or the polymer porous membrane 40 supported by the support 50) are crushed or reduced in size by crushing or melting, thereby processing the reinforcing portion 45 into a bulk structure. When the diaphragm 4 includes the polymer porous membrane 40 supported by the support 50, the support 50 and the polymer porous membrane 40 are welded together by resin in the reinforcing portion 45, which is expected to further improve the physical strength of the diaphragm 4.

[0028] The porosity of the reinforcing portion 45 is desirably 0 or close to 0, and is preferably 1 / 10 or less of the porosity of the portion of the separator region 43 excluding the reinforcing portion 45. The reinforcing portion 45 having such a porosity has higher strength against friction and higher burst strength (i.e., resistance to tearing) than the portion of the separator region 43 excluding the reinforcing portion 45. The porosity is calculated by dividing the total volume by V [m 3 ], the volume of the gap is v [m 3 When voids exist in the reinforcing portion 45, the voids in the reinforcing portion 45 are preferably closed pores (also called closed pores).

[0029] Because ion exchange does not occur in the reinforcing portions 45, an excessive area of ​​the reinforcing portions 45 reduces the electrolysis performance of the electrolytic cell 1. Therefore, the total area of ​​the reinforcing portions 45 in the separator region 43 is preferably 10% or less, and more preferably 5% or less, of the area of ​​the separator region 43.

[0030] 3 and 6, the reinforcing portion 45 has a line shape extending in the vertical direction. The surface of the reinforcing portion 45, which has a bulk structure, has smaller or fewer irregularities than the surface of the separator region 43 excluding the reinforcing portion 45. In the polymer porous membrane 40, bubbles tend to remain on the surface due to the irregularities on the surface, but the reinforcing portion 45 has a relatively smooth surface, so the bubbles tend to disengage. Therefore, the reinforcing portion 45, which has a line shape extending in the vertical direction, serves as a gas flow path and promotes the rise of bubbles, thereby contributing to improved electrolysis efficiency.

[0031] The shape of the reinforcing portion 45 is not limited to the above, and the reinforcing portion 45 may be provided in an appropriate shape depending on the size and shape of the separator region 43 of the membrane 4.

[0032] For example, as shown in Fig. 7, reinforcing portion 45 may be a lattice pattern of lines extending in the vertical direction and lines extending in the horizontal direction. Alternatively, as shown in Fig. 8, reinforcing portion 45 may be a lattice pattern of lines extending obliquely from the vertical direction to the horizontal direction. Reinforcing portion 45 in a lattice pattern can reinforce diaphragm 4 while maintaining the stretchability of diaphragm 4.

[0033] 9, the reinforcing portion 45 may be a chain line extending in the horizontal direction (or the vertical direction). It is desirable that a plurality of chain lines are arranged in parallel in the separator region 43, and the dashes (-) of the chain lines are arranged in a staggered pattern (i.e., staggered).

[0034] [Method for manufacturing diaphragm 4] The method for manufacturing the membrane 4 having the above configuration includes a step of producing the polymer porous membrane 40 (or the polymer porous membrane 40 supported on the support 50) and a step of forming the bulk portion 42 in the polymer porous membrane 40.

[0035] The diaphragm 4 is a porous membrane for alkaline water electrolysis to which a bulk portion 42 has been added. Therefore, the polymer porous membrane 40 of the diaphragm 4 (or the polymer porous membrane 40 supported on the support 50) can be a polymer porous membrane manufactured by a known method for manufacturing a diaphragm for alkaline water electrolysis. The method for producing the polymer porous membrane 40 is not particularly limited, and for example, a known phase separation method may be employed. In this case, a membrane-forming stock solution is prepared by dissolving the organic polymer resin and additives in an organic solvent, and the membrane-forming stock solution is applied to a substrate to a predetermined thickness to produce a coated film sheet. The coated film sheet is immersed in a non-solvent to induce phase separation of the membrane-forming stock solution to form pores, and excess water is then removed to obtain the polymer porous membrane 40. When preparing a polymer porous membrane 40 supported on a support 50, the support 50 may be used instead of the substrate in the above-described process for producing the polymer porous membrane 40.

[0036] The reinforcing portion 45 can be formed in the polymer porous membrane 40 by applying pressure or heat. Pressing or the like can be used as the pressure application method. In this case, by applying pressure to the polymer porous membrane 40 (or the polymer porous membrane 40 supported on the support 50) using a mold for the reinforcing portion 45, the pressurized portion of the polymer porous membrane 40 is compressed in the thickness direction, the structure becomes bulky, and the reinforcing portion 45 is formed. In addition, impulse welding, ultrasonic welding, high-frequency welding, laser welding, hot plate welding, heat pressing, or the like can be used as the heating method. In this case, by heating the polymer porous membrane 40 (or the polymer porous membrane 40 supported on the support 50) in accordance with the shape of the reinforcing portion 45, the resin in the heated portion melts and welds, the structure becomes bulky, and the reinforcing portion 45 is formed.

[0037] [Summary] The diaphragm 4 for alkaline water electrolysis according to a first aspect of the present disclosure is a diaphragm 4 for alkaline water electrolysis separating an anode chamber 48 and a cathode chamber 49 of an alkaline water electrolytic cell 1, The alkaline water electrolytic cell (1) includes a porous polymer membrane (40) integrally having a seal region (41) sandwiched between cell-constituting members and a separator region (43) disposed on the inner circumferential side of the seal region (41), The separator region 43 has a bulk-structured reinforcing portion 45. Here, the "bulk structure" may include a non-porous structure in which there are no voids such as pores, or a porous structure in which pores are present but the porosity is extremely low compared to the portion of the separator region 43 excluding the reinforcing portion 45.

[0038] The reinforcing portion 45 of the diaphragm 4 configured as described above is formed, for example, by converting the porous structure of the portion of the separator region 43 corresponding to the reinforcing portion 45 into a bulk structure by crimping or welding. The reinforcing portion 45 having a bulk structure is more resistant to tearing and has superior abrasion resistance than the porous structure of the separator region 43 (excluding the reinforcing portion 45). Furthermore, by providing such a reinforcing portion 45 at any position in the separator region 43, the physical strength of the diaphragm 4 that can withstand tearing and abrasion can be improved.

[0039] The diaphragm 4 for alkaline water electrolysis according to a second aspect of the present disclosure is the diaphragm 4 for alkaline water electrolysis according to the first aspect, further comprising a porous support 50 that supports the polymer porous membrane 40, in which the resin of the polymer porous membrane 40 is impregnated into the support 50, and the polymer porous membrane 40 and the support 50 are welded to each other at a reinforcing portion 45.

[0040] According to the membrane 4 having the above configuration, the reinforcing portion 45 has a bulk structure in which the support 50 and the porous polymer membrane 40 are welded together, and therefore the physical strength of the membrane 4 is expected to be further improved.

[0041] A diaphragm 4 for alkaline water electrolysis according to a third aspect of the present disclosure is the diaphragm 4 for alkaline water electrolysis according to the first or second aspect, wherein the reinforcing parts 45 are linear and extend in the vertical direction.

[0042] In the diaphragm 4 having the above-described configuration, the surface of the reinforcing portion 45, which has a bulk structure, is smoother and less likely to trap gas bubbles than the portion of the separator region 43 other than the reinforcing portion 45, and the linear reinforcing portion 45 extending in the vertical direction forms a vertical gas flow path on the surface of the diaphragm 4. Therefore, the reinforcing portion 45 promotes the rising of gas bubbles, which contributes to improving the electrolysis efficiency.

[0043] A diaphragm 4 for alkaline water electrolysis according to a fourth aspect of the present disclosure is the diaphragm 4 for alkaline water electrolysis according to the first or second aspect, wherein the reinforcing portion 45 has a lattice pattern.

[0044] According to the diaphragm 4 having the above configuration, the reinforcing portions 45 can reinforce the diaphragm 4 while maintaining the stretchability of the diaphragm 4. Furthermore, the upward linear reinforcing portions 45 forming a lattice form vertical gas flow paths on the surface of the diaphragm 4 in the same manner as described above.

[0045] A diaphragm 4 for alkaline water electrolysis according to a fifth aspect of the present disclosure is the diaphragm 4 for alkaline water electrolysis according to the first or second aspect, wherein the reinforcing parts 45 are in the form of chain lines extending in the transverse direction.

[0046] According to the diaphragm 4 having the above-described configuration, the reinforcing portion 45 can reinforce the diaphragm 4 while maintaining the stretchability of the diaphragm 4.

[0047] A diaphragm 4 for alkaline water electrolysis according to a sixth aspect of the present disclosure is the diaphragm 4 for alkaline water electrolysis according to any one of the first to fifth aspects, wherein part of the reinforcing portion 45 extends into the sealing region 41.

[0048] According to the membrane 4 having the above-described configuration, the reinforcing portion 45 can reinforce not only the separator region 43 but also the seal region 41 .

[0049] A diaphragm 4 for alkaline water electrolysis according to a seventh aspect of the present disclosure is the diaphragm 4 for alkaline water electrolysis according to any one of the first to sixth aspects, wherein the total area of ​​the reinforcing portions 45 relative to the area of ​​the separator regions 43 is 10% or less.

[0050] The diaphragm 4 having the above-described configuration can maintain electrolytic performance while achieving a good balance between physical strength.

[0051] A diaphragm 4 for alkaline water electrolysis according to an eighth aspect of the present disclosure is the diaphragm 4 for alkaline water electrolysis according to any one of the first to seventh aspects, wherein the porosity of the reinforcing portions 45 is not more than 1 / 10 of the porosity of the separator region 43 excluding the reinforcing portions 45.

[0052] The porosity of the reinforcing portion 45 is not particularly limited, but by compressing or melting the polymer porous membrane 40 so that the porosity of the reinforcing portion 45 is sufficiently small compared to the portion of the separator region 43 other than the reinforcing portion 45, the reinforcing portion 45 can be made resistant to tearing and has physical strength against wear.

[0053] The alkaline water electrolytic cell 1 according to the ninth item of the present disclosure comprises: an anode chamber frame 21 that defines an anode chamber 48; a cathode chamber frame 22 defining a cathode chamber 49; an anode 31 housed in an anode chamber 48; a cathode 71 accommodated in the cathode chamber 49; and a diaphragm (4) for alkaline water electrolysis according to any one of items (1) to (8), which is disposed between the anode chamber frame (21) and the cathode chamber frame (22) and separates the anode chamber (48) from the cathode chamber (49).

[0054] The bulk-structured reinforcing portion 45 of the diaphragm 4 is less likely to break and has superior abrasion resistance compared to the porous-structured separator region 43 (excluding the reinforcing portion 45). By providing such a reinforcing portion 45 at any position in the separator region 43, the physical strength of the diaphragm 4 that can withstand breakage and abrasion can be improved. Therefore, the electrolytic cell 1 configured as described above can be provided with a diaphragm 4 that has excellent physical strength.

[0055] A tenth aspect of the present disclosure relates to a method for producing a diaphragm 4 for alkaline water electrolysis that separates an anode chamber 48 from a cathode chamber 49 of an alkaline water electrolytic cell 1, the method comprising: a step of preparing a porous polymer membrane (40) integrally having a seal region (41) to be sandwiched between cell-constituting members in an alkaline water electrolytic cell (1) and a separator region (43) disposed on the inner circumferential side of the seal region (41); and forming a bulk structure reinforcing portion 45 in the separator region 43 of the porous polymer membrane 40 by applying pressure or heat.

[0056] According to the above-described method for manufacturing the diaphragm 4, the diaphragm 4 having the reinforcing portion 45 can be easily manufactured.

[0057] The present disclosure has been presented for purposes of illustration and description and is not intended to be limited to the form disclosed herein. For example, in the foregoing Detailed Description, various features of the present disclosure are grouped together in a single embodiment for the purpose of streamlining the disclosure, but some of the features may also be combined. Also, the features included in the present disclosure may be combined into alternative embodiments, configurations, or aspects other than those discussed above. [Explanation of symbols]

[0058] 1: Alkaline water electrolysis tank 4: Diaphragm for alkaline water electrolysis 21: Anode chamber frame 22: Cathode chamber frame 31: Anode 40: Polymer porous membrane 41: Sealing area 43: Separator area 44: Edge region 45: Reinforcement 48:Anode chamber 49: Cathode chamber 71 :Cathode

Claims

1. A diaphragm for alkaline water electrolysis separating an anode chamber and a cathode chamber of an alkaline water electrolytic cell, comprising: a porous polymer membrane integrally having a seal region that is sandwiched between tank-constituting members in the alkaline water electrolytic tank and a separator region that is disposed on the inner circumferential side of the seal region, The separator region has a bulk structural reinforcement portion. Diaphragm for alkaline water electrolysis.

2. Further provided is a porous support that supports the polymeric porous membrane, the support is impregnated with the resin of the polymer porous membrane, and the polymer porous membrane and the support are welded together at the reinforcing portion; The diaphragm for alkaline water electrolysis according to claim 1.

3. The reinforcing portion has a line shape extending in the vertical direction. The diaphragm for alkaline water electrolysis according to claim 1 or 2.

4. The reinforcing portion has a lattice shape. The diaphragm for alkaline water electrolysis according to claim 1 or 2.

5. The reinforcing portion has a chain line shape extending in the horizontal direction. The diaphragm for alkaline water electrolysis according to claim 1 or 2.

6. A portion of the reinforcing portion extends into the sealing area. The diaphragm for alkaline water electrolysis according to claim 1 or 2.

7. the total area of ​​the reinforcing portions is 10% or less of the area of ​​the separator region; The diaphragm for alkaline water electrolysis according to claim 1 or 2.

8. the porosity of the reinforcing portion is 1 / 10 or less of the porosity of the portion of the separator region excluding the reinforcing portion; The diaphragm for alkaline water electrolysis according to claim 1 or 2.

9. an anode chamber frame defining the anode chamber; a cathode chamber frame defining the cathode chamber; an anode housed in the anode chamber; a cathode accommodated in the cathode chamber; the diaphragm for alkaline water electrolysis according to claim 1 or 2, which is disposed between the anode chamber frame and the cathode chamber frame to separate the anode chamber from the cathode chamber. Alkaline water electrolyzer.

10. A method for manufacturing a diaphragm for alkaline water electrolysis separating an anode chamber and a cathode chamber of an alkaline water electrolytic cell, comprising: preparing a porous polymer membrane integrally having a seal region to be sandwiched between cell-constituting members in the alkaline water electrolytic cell and a separator region disposed on the inner circumferential side of the seal region; forming a bulk structure reinforcing portion in the separator region of the polymer porous membrane by compression bonding or welding; Method for manufacturing diaphragms for alkaline water electrolysis.

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