Elastic pads for alkaline water electrolyzers

Abstract

An elastic pad for an alkaline water electrolyzer comprises at least one metal mesh woven or braided with metal wires and having spring elasticity in the thickness direction, wherein the metal wires are single wires with a wire diameter of 0.16 mm to 0.29 mm or a wire bundle formed by bundling a plurality of single wires with a wire diameter of 0.08 mm to 0.15 mm, or a combination thereof.

Description

Technical Field

[0001] The present invention relates to an elastic pad used in an electrolytic cell for alkaline water electrolysis, and more particularly to an elastic pad used in a zero-gap electrolytic cell for alkaline water electrolysis, an alkaline water electrolytic cell having the elastic pad, and a gas production method using the alkaline water electrolytic cell. Background Art

[0002] As a method for producing hydrogen and oxygen, an alkaline water electrolysis method is known. The alkaline water electrolysis method uses an alkaline aqueous solution (alkaline water) dissolved with an alkaline metal hydroxide (such as NaOH, KOH, etc.) as an electrolyte to electrolyze water, thereby generating hydrogen from the cathode and oxygen from the anode. As an electrolytic cell for alkaline water electrolysis, there is a known electrolytic cell: it has an anode chamber and a cathode chamber divided by an ion-permeable diaphragm, an anode is arranged in the anode chamber, and a cathode is arranged in the cathode chamber. In addition, in order to reduce energy loss, there is proposed an electrolytic cell (zero-gap electrolytic cell): it has a zero-gap structure, and the zero-gap structure is that the anode and the cathode are respectively maintained in direct contact with the diaphragm.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 3616265

[0006] Patent Document 2: Japanese Patent No. 3707985

[0007] Patent Document 3: Japanese Patent No. 5695418

[0008] Patent Document 4: Japanese Patent No. 6318678

[0009] Patent Document 5: International Publication No. 2013 / 191140

[0010] Patent Document 6: Japanese Patent No. 6093351

[0011] Patent Document 7: Japanese Patent No. 4453973

[0012] Patent Document 8: Japanese Patent Application Publication No. 2015-117417 Summary of the invention

[0013] Problem that the invention aims to solve

[0014] Figure 1FIG. 1 is a partial cross-sectional view schematically illustrating a zero-gap electrolytic cell 900 according to a conventional embodiment. The zero-gap electrolytic cell 900 comprises: electrode chamber units 910, 910, ..., which have a flange portion 912 and a conductive partition wall 911 that separates the anode chamber A and the cathode chamber C; an ion-permeable diaphragm 920, which is arranged between adjacent electrode chamber units 910, 910; gaskets 930, 930, which are arranged between the diaphragm 920 and the flange portion 912 of the electrode chamber unit 910 and clamp the peripheral portion of the diaphragm 920; an anode 940, which is retained by a conductive rib 913, 913, ... that is upright from the partition wall 911 of one electrode chamber unit; a collector 950, which is retained by a conductive rib 914, 914, ... that is upright from the partition wall 911 of another electrode chamber unit; and a relatively soft cathode 970, which is retained by a conductive elastic pad 960 that is arranged in contact with the collector 950. The peripheral portion of the cathode 970 and the peripheral portion of the conductive elastic pad 960 are fixed to the peripheral portion of the current collector 950. In the zero-gap electrolytic cell 900, the relatively soft cathode 970 is pressed toward the diaphragm 920 and the anode 940 by the conductive elastic pad 960, so that the diaphragm 920 is sandwiched between the adjacent cathode 970 and anode 940. As a result, the diaphragm 920 is in direct contact with the anode 940 and the cathode 970 (zero gap), so the solution resistance between the anode 940 and the cathode 970 is reduced, and thus the energy loss is reduced.

[0015] Conventionally, as a zero-gap alkaline water electrolyzer, an electrolyzer obtained by replacing the ion exchange membrane with a diaphragm (920) in a zero-gap electrolyzer for sodium chloride electrolysis has been generally used.

[0016] Generally, in a zero-gap electrolyzer, it is preferred that the proportion of the zero-gap portion (zero-gap region) in the electrode area is large. This is because when the portion that is not zero-gap (the anode or cathode is not in direct contact with the ion exchange membrane or diaphragm) is large, the solution resistance between the electrodes in this portion becomes large, which increases the operating voltage.

[0017] In order to achieve zero gap, the electrode is preferably completely flat, but the electrode is often bent due to gravity, dimensional error, etc. When there is a bend in the electrode, a gap is easily generated between the electrode and the membrane. From the perspective of increasing the proportion of the zero gap area in the electrode area even when there is a bend in the electrode, it is considered that it is advantageous if the surface pressure of the electrode clamping the membrane is large.

[0018] However, in a zero-gap electrolyzer equipped with an ion exchange membrane such as a sodium chloride electrolyzer, the bubbles generated by the electrolytic reaction cause the electrodes and the ion exchange membrane to vibrate, thereby causing the surface of the ion exchange membrane clamped between the electrodes in a zero-gap state to wear, the function of the ion exchange group to be impaired, and there is a problem that the ion exchange capacity of the ion exchange membrane deteriorates over time. Such a problem of ion exchange membrane degradation due to vibration caused by bubble generation is particularly obvious when the surface pressure of the electrodes holding the ion exchange membrane is large. Ion exchange membranes are generally expensive, and promoting their deterioration has a profound adverse effect on the operating cost of the electrolysis process. Therefore, in a zero-gap electrolyzer equipped with an ion exchange membrane, in order to enable the expensive ion exchange membrane to be used for a long time, it is required to suppress the surface pressure of the electrodes holding the ion exchange membrane.

[0019] For example, Patent Document 1 describes an ion exchange membrane electrolyzer, which is composed of an anode chamber and a cathode chamber divided by a cation exchange membrane, an anode chamber and a cathode chamber, and has a structure in which the two electrodes are close to each other across the ion exchange membrane, characterized in that one electrode has a hole with an area of ​​0.05 mm 2 ~1.0mm 2 The porous body has multiple holes and an opening rate of 20% or more, and is a relatively soft porous plate with a bending flexibility of 0.05mm / g or more. The other electrode is a rigid porous plate. The relatively soft porous plate electrode is elastically padded with 20g / cm 2 ~60g / cm 2 The elastic pad is pressed against the other electrode with a pressure of , and the elastic pad is composed of a metal wire aggregate, which is obtained by overlapping a plurality of metal meshes woven and curled using a wire bundle composed of 2 to 8 metal wires with a wire diameter of 0.02 mm to 0.09 mm, and has a rebound force of 30 g / cm when deformed by 50%. 2 ~50g / cm 2 The pressure at 20% compression deformation is 10g / cm 2 ~30g / cm 2 of elasticity".

[0020] On the other hand, the general diaphragm used in the electrolysis of alkaline water is a porous film, and its ion exchange effect does not rely on the chemical action of the ion exchange group, so it is believed that even if the surface pressure of the electrode clamping diaphragm is large, the ion exchange capacity of the diaphragm is also difficult to reduce. That is, in the previous zero gap type alkaline water electrolyzer, if the surface pressure of the electrode clamping diaphragm can be increased, the life of the diaphragm will not be damaged to a large extent, even if the pressure in the electrolyzer changes, the zero gap structure can be maintained more stably, and it is possible to expect to increase the ratio of the zero gap region in the electrode area and improve energy efficiency. However, in the previous zero gap type alkaline water electrolyzer, when it is desired to improve the surface pressure of the electrode clamping diaphragm, the elastic pad is crushed, and therefore the zero gap structure can not be maintained, and the uniformity of the surface pressure distribution between the electrode and the diaphragm is reduced. When the surface pressure distribution between the electrode and the diaphragm becomes uneven, the distribution of the electrolysis current on the electrode surface is also easily uneven. The uneven distribution of the electrolysis current on the electrode surface causes the increase of the operating voltage and the reduction of energy efficiency.

[0021] The present invention aims to provide an elastic pad for an alkaline water electrolysis cell capable of improving the energy efficiency of the alkaline water electrolysis cell, an alkaline water electrolysis cell having the elastic pad, and a gas production method using the alkaline water electrolysis cell.

[0022] Solutions for solving problems

[0023] The present invention includes the following technical solutions [1] to

[14] .

[0024] [1] An elastic pad for an alkaline water electrolyzer, wherein the elastic pad for an alkaline water electrolyzer comprises at least one metal mesh woven or braided with metal wires and having spring elasticity in a thickness direction,

[0025] The metal wire is a single wire with a wire diameter of 0.16 mm to 0.29 mm, or a wire bundle formed by bundling a plurality of single wires with a wire diameter of 0.08 mm to 0.15 mm, or a combination thereof.

[0026] [2] The elastic pad for an alkaline water electrolyzer according to [1], wherein

[0027] The elastic pad for alkaline water electrolysis tank has a rebound force per unit area of ​​100 gf / cm when it is compressed and deformed by 50%. 2 ~450gf / cm 2 .

[0028] [3] The elastic pad for an alkaline water electrolyzer according to [1] or [2], wherein

[0029] When the elastic pad for alkaline water electrolyzer is compressed and deformed by 50% twice, the rebound force per unit area at the second compression deformation of 50% is 40 gf / cm 2 above.

[0030] [4] The elastic pad for an alkaline water electrolyzer according to any one of [1] to [3], wherein

[0031] The metal mesh is formed into a wave shape having an amplitude in a thickness direction of the metal mesh.

[0032] [5] The elastic pad for an alkaline water electrolyzer according to [4], wherein

[0033] The plurality of metal meshes overlap in the thickness direction,

[0034] The metal meshes in each group of two adjacent metal meshes overlap so that the ridges of the wave shape formed in one metal mesh of the group intersect with the ridges of the wave shape formed in the other metal mesh of the group when the elastic pad is viewed from above.

[0035] [6] The elastic pad for an alkaline water electrolyzer according to any one of [1] to [5], wherein

[0036] The total thickness of the elastic pad for the alkaline water electrolyzer is 7.5 mm to 10 mm.

[0037] [7] An alkaline water electrolysis cell, comprising:

[0038] an anode chamber that receives the anode and produces oxygen;

[0039] a cathode chamber that receives the cathode and produces hydrogen;

[0040] an ion-permeable membrane that separates the anode chamber from the cathode chamber; and

[0041] A first elastic pad is the elastic pad for an alkaline water electrolyzer according to any one of [1] to [6].

[0042] The first electrode as the cathode is a flexible porous plate and is pressed toward the second electrode as the anode by the first elastic pad.

[0043] [8] An alkaline water electrolysis cell, wherein the alkaline water electrolysis cell comprises:

[0044] an anode chamber that receives the anode and produces oxygen;

[0045] a cathode chamber that receives the cathode and produces hydrogen;

[0046] an ion-permeable membrane that separates the anode chamber from the cathode chamber; and

[0047] A first elastic pad is the elastic pad for an alkaline water electrolyzer according to any one of [1] to [6].

[0048] The first electrode as the anode is a flexible porous plate and is pressed toward the second electrode as the cathode by the first elastic pad.

[0049] [9] The alkaline water electrolyzer according to [7] or [8], wherein the second electrode is a rigid porous plate.

[0050]

[10] The alkaline water electrolyzer according to [9], further comprising a second elastic pad, wherein the second elastic pad is the elastic pad for an alkaline water electrolyzer according to any one of [1] to [6],

[0051] The second electrode is pressed toward the first electrode by the second elastic pad.

[0052]

[11] The alkaline water electrolyzer according to [7] or [8], further comprising a second elastic pad, the second elastic pad being the elastic pad for an alkaline water electrolyzer according to any one of [1] to [6],

[0053] The second electrode is a flexible second porous plate.

[0054] The second electrode is pressed toward the first electrode by the second elastic pad.

[0055]

[12] The alkaline water electrolyzer according to [7] or [8], further comprising a conductive rigid current collector disposed in contact with the second electrode,

[0056] The second electrode is a flexible second porous plate.

[0057] The second electrode is supported by the rigid current collector.

[0058]

[13] The alkaline water electrolyzer according to

[12] , further comprising a second elastic pad, the second elastic pad being the elastic pad for an alkaline water electrolyzer according to any one of [1] to [6],

[0059] The second electrode is pressed toward the first electrode by the second elastic pad via the rigid current collector.

[0060]

[14] A gas production method, which is a method for producing hydrogen and oxygen by electrolyzing alkaline water, wherein the method comprises:

[0061] (a) A step of electrolyzing alkaline water using the alkaline water electrolysis cell described in any one of [7] to

[13] .

[0062] Effects of the Invention

[0063] According to the first technical solution of the present invention, the elastic pad for alkaline water electrolyzer is woven or braided by a metal mesh made of predetermined metal wires, and the resilience can be improved. By using the elastic pad for alkaline water electrolyzer of the present invention as a conductive elastic pad in an alkaline water electrolyzer, the surface pressure of the electrode clamping the diaphragm can be increased without damaging the uniformity of the surface pressure, and the proportion of the zero gap area in the electrode area can be increased, thereby improving the energy efficiency of the alkaline water electrolyzer.

[0064] According to the alkaline water electrolyzer of the second technical solution of the present invention, one electrode is pressed toward the other electrode by the elastic pad of the first technical solution of the present invention. As a result, the surface pressure of the electrodes holding the diaphragm can be increased without damaging the uniformity of the surface pressure, and the proportion of the zero gap area in the electrode area can be increased, so that the operating voltage can be reduced and the energy efficiency can be improved.

[0065] According to the gas production method of the third aspect of the present invention, electrolysis is performed using the alkaline water electrolysis cell of the second aspect of the present invention, so that the operating voltage can be reduced and the energy efficiency can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 1 is a cross-sectional view schematically illustrating a zero-gap electrolytic cell 900 according to a conventional embodiment.

[0067] Figure 2 1 is a diagram schematically illustrating an elastic pad 100 for an alkaline water electrolyzer according to an embodiment of the present invention. Figure 2 (A) is the top view, Figure 2 (B) is Figure 2 The BB section view of (A) is as follows: Figure 2 (C) is Figure 2 (A) is a cross-sectional view taken along the CC direction. Figure 2 (D) is Figure 2 (A) is a cross-sectional view taken along the DD line.

[0068] Figure 3 FIG. 1 is a partially enlarged top view of a metal mesh 10 according to an embodiment.

[0069] Figure 4 is a diagram schematically illustrating a planar metal mesh 10-pre1. Figure 4 (A) is a top view of the metal mesh 10-pre1. Figure 4 (B) is a front view of the metal mesh 10-pre1.

[0070] Figure 5 is a diagram schematically illustrating a cylindrical metal mesh 10-cyl and a metal mesh 10-pre2 obtained from the cylindrical metal mesh 10-cyl. Figure 5 (A) is a top view of a cylindrical metal mesh 10-cyl. Figure 5 (B) is the front view of the cylindrical metal mesh 10-cyl, Figure 5 (C) is a top view of the metal mesh 10-pre2. Figure 5 (D) is the main view of the metal mesh 10-pre2.

[0071] Figure 6 FIG. 1 is a plan view schematically illustrating an elastic pad 200 for an alkaline water electrolyzer according to another embodiment of the present invention.

[0072] Figure 7 FIG. 1 is a plan view schematically illustrating an elastic pad 300 for an alkaline water electrolyzer according to another embodiment of the present invention.

[0073] Figure 8 2 is a diagram schematically illustrating an elastic pad 400 for an alkaline water electrolyzer according to another embodiment of the present invention. Figure 8 (A) is a top view of the elastic pad 400, Figure 8 (B) is a front view of the elastic pad 400, Figure 8 (C) is Figure 8 (B) is a cross-sectional view taken along the CC direction.

[0074] Fig. 9 is a perspective top view of the elastic pad 400 .

[0075] Fig.10 1 is a perspective plan view of an elastic pad 500 for an alkaline water electrolyzer according to another embodiment of the present invention.

[0076] Fig.11 FIG. 1 is a perspective top view of an elastic pad 600 for an alkaline water electrolyzer according to another embodiment of the present invention.

[0077] Fig.12 1 is a cross-sectional view schematically illustrating an alkaline water electrolysis cell 1000 according to one embodiment of the present invention.

[0078] Fig.13 FIG. 2 is a cross-sectional view schematically illustrating an alkaline water electrolysis cell 2000 according to another embodiment of the present invention.

[0079] Fig.14 FIG. 1 is a cross-sectional view schematically illustrating an alkaline water electrolysis cell 3000 according to another embodiment of the present invention.

[0080] Fig.15FIG. 4 is a cross-sectional view schematically illustrating an alkaline water electrolysis cell 4000 according to another embodiment of the present invention.

[0081] Fig.16 FIG. 1 is a cross-sectional view schematically illustrating an alkaline water electrolysis cell 5000 according to another embodiment of the present invention.

[0082] Fig.17 FIG. 1 is a cross-sectional view schematically illustrating an alkaline water electrolysis cell 6000 according to another embodiment of the present invention.

[0083] Fig.18 (A) is a plan view schematically illustrating a metal container 90 for measuring the resilient force per unit area when the elastic pad is compressed and deformed. Fig.18 (B) is Fig.18 BB cross-sectional view of (A).

[0084] Fig.19 (A) is a schematic diagram illustrating Fig.18 (B) is a cross-sectional view showing a state in which a test piece 94 is arranged on a bottom plate 91. Fig.19 (B) is a cross-sectional view schematically illustrating the positional relationship among the metal container 90 , the test piece 94 , and the pressing plate 95 before the pressing plate 95 comes into contact with the test piece 94 . Fig.19 (C) schematically illustrates the process of lowering the pressing plate until the thickness of the test piece 94 reaches the initial thickness t init sectional view showing the positional relationship among the metal container 90, the test piece 94 and the pressing plate 95 at the time when the pressure is 50% of the load. Fig.19 (D) is a cross-sectional view schematically illustrating a state in which the pressing plate 95 is lifted and the shape of the test piece 94 is fully restored. Fig.19 (E) is a cross-sectional view schematically illustrating the positional relationship among the metal container 90, the test piece 94, and the pressing plate 95 during the second 50% compressive deformation. DETAILED DESCRIPTION

[0085] The above-mentioned effects and advantages of the present invention can be clearly understood according to the methods for implementing the invention described below. Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to these methods. In addition, the drawings may not reflect accurate dimensions. In addition, in the drawings, some figure marks are sometimes omitted. In this specification, regarding numerical values ​​A and B, unless otherwise specified, expressions such as "A to B" mean "greater than or equal to A and less than or equal to B". In the case where only numerical value B is accompanied by a unit in the expression, the unit is also applied to numerical value A. In addition, regarding the words "or" and "or", unless otherwise specified, they mean logical or. In addition, regarding elements E1 and E2, expressions such as "E1 and / or E2" mean "E1 or E2, or a combination thereof", and regarding elements E1, ..., E N (N is an integer greater than 3), "E1, ..., E N-1 , and / or E N "This expression means "E1, ..., E N-1 , or E N , or a combination thereof".

[0086] <1. Elastic pad for alkaline water electrolyzer>

[0087] Figure 2 FIG. 1 is a diagram schematically illustrating an elastic pad 100 for an alkaline water electrolyzer (hereinafter also referred to as “elastic pad 100 ”) according to an embodiment of the present invention. Figure 2 middle, Figure 2 (A) is a top view of the elastic pad 100, Figure 2 (B) is Figure 2 The BB section view of (A) is as follows: Figure 2 (C) is Figure 2 (A) is a cross-sectional view taken along the CC direction. Figure 2 (D) is Figure 2 (A) is a cross-sectional view taken along the DD line.

[0088] like Figure 2 As shown in (A), the elastic pad 100 includes a metal mesh 10. The metal mesh 10 is a metal mesh woven or braided using metal wires and has spring elasticity in the thickness direction. Figure 2 (B) Figure 2 (C) and Figure 2 As shown in (D), the metal mesh 10 is shaped so that the metal mesh 10 has a substantially entire surface in the thickness direction (with respect to the metal mesh 10). Figure 2 The wave shape (triangular wave shape) has an amplitude in the direction perpendicular to the paper surface. Figure 2 In (A), the ridges (ridge lines) R, R, ... of the wave shape are represented by solid lines. Figure 2As shown in (D), there are valleys (valley lines) V, V, ... between adjacent ridges (ridge lines) R, R, .... The metal mesh 10 is shaped into a wave shape having an amplitude in the thickness direction, and the metal mesh 10 has spring elasticity in the thickness direction. When the metal mesh 10 is viewed from above ( Figure 2 In (A), due to the wave shape given to the metal mesh 10, the straight ridges (ridge lines) R, R, ... appear parallel. In addition, Figure 2 The arrow L in (A) indicates the weaving direction of the metal mesh 10 (described later), and the arrow W indicates the weaving width direction of the metal mesh 10 (described later).

[0089] Figure 3 FIG. 1 is a partially enlarged top view of a metal mesh 10 according to an embodiment. Figure 3 Sometimes, Figure 2 The element annotations shown in Figure 2 For the sake of convenience, the wave shape given to the metal mesh 10 is not shown in FIG. Figure 3 As shown in Figure 3 As shown, the metal mesh 10 is woven using metal wires 1-1, 1-2, 1-3, 1-4, ... (hereinafter, also referred to as "metal wires 1-n" (n=1, 2, ...) or simply "metal wire 1").

[0090] The metal wire 1 is a single wire with a wire diameter of 0.16 mm to 0.29 mm or a wire bundle formed by bundling multiple single wires with a wire diameter of 0.08 mm to 0.15 mm, or a combination thereof. That is, each metal wire 1 can be a single wire with a wire diameter of 0.16 mm to 0.29 mm, or a wire bundle formed by bundling multiple single wires with a wire diameter of 0.08 mm to 0.15 mm. In addition, the metal mesh 10 can also be a mixed fabric or mixed braid of single wires and wire bundles. For example, the metal wires 1-1, 1-3, ...1-(2k-1), ... can also be single wires, and the metal wires 1-2, 1-4, ...1-(2k), ... can be wire bundles (k=1, 2, ...).

[0091] When the metal wire 1 is a single wire, its wire diameter is 0.16 mm to 0.29 mm as described above, preferably 0.16 mm to 0.25 mm. When the metal wire 1 is a wire harness, the wire diameter of the single wire constituting the wire harness is 0.08 mm to 0.15 mm as described above, preferably 0.08 mm to 0.12 mm. By making the wire diameter above the above lower limit value, the spring elasticity of the elastic pad 100 can be improved. Therefore, when the elastic pad 100 is used in an alkaline water electrolyzer, even if the pressure in the electrolyzer changes, the zero-gap structure can be maintained more stably, and the surface pressure can be increased without impairing the uniformity of the surface pressure for clamping the diaphragm by the electrode, and the proportion of the zero-gap region in the electrode area can be increased, thereby improving the energy efficiency. In addition, by making the wire diameter below the above upper limit value, the repeated resilience can be improved, and sufficient resilience can be maintained even in long-term use. Therefore, the energy efficiency of the alkaline water electrolyzer can be maintained at a high level for a long time.

[0092] The number of single wires constituting the wire harness is not particularly limited, but is preferably 2 to 4, and can be 2 to 3 in one embodiment. By making the number of single wires constituting the wire harness above the above lower limit value, the spring elasticity of the elastic pad 100 can be improved. Therefore, when the elastic pad 100 is used in an alkaline water electrolyzer, even if the pressure in the electrolyzer changes, the zero-gap structure can be maintained more stably, and the surface pressure can be increased without impairing the uniformity of the surface pressure for clamping the diaphragm by the electrode, and the proportion of the zero-gap region in the electrode area can be increased, thereby improving the energy efficiency. In addition, by making the number of single wires constituting the wire harness below the above upper limit value, mechanical damage to the surface of the diaphragm can be suppressed.

[0093] As the metal wire 1, a metal wire with relatively high toughness and alkali resistance can be preferably used. Moreover, since the elastic pad 100 also functions as a current collector, the metal wire 1 is preferably a metal wire with a relatively high conductivity. As examples of such metal wires, nickel wires, mild steel wires, stainless steel wires such as SUS304, SUS310, SUS310S, SUS316, SUS316L, etc., and metal wires obtained by nickel-plating the above substances can be preferably selected. In one embodiment, metal wires of multiple different materials can also be used in combination. For example, mild steel wires and stainless steel wires with relatively high toughness but not particularly excellent conductivity can be used in combination with nickel wires with relatively high conductivity but not particularly excellent toughness. In addition, in one embodiment, a wire harness formed by bundling multiple single wires of multiple different materials can also be used.

[0094] Figure 3 The shown knitting method is knitting (Japanese: メリヤス編み). Figure 3 The arrow L in it indicates the traveling direction of knitting, and the arrow W perpendicular to the arrow L indicates the width direction of knitting. As Figure 3As shown, each metal wire 1-n is bent in a manner that alternately and repeatedly forms a first coil portion 1-nla and a second coil portion 1-nlb protruding in opposite directions. That is, in the length direction of each metal wire 1-n, the first coil portion 1-nla, 1-nla, ... and the second coil portion 1-nlb, 1-nlb, ... are alternately arranged. For example, the metal wire 1-1 is bent in a manner that alternately and repeatedly forms a first coil portion 1-1la and a second coil portion 1-1lb protruding in opposite directions, as a result, in the length direction of the metal wire 1-1, the first coil portion 1-1la, 1-1la, ... and the second coil portion 1-1lb, 1-1lb, ... are alternately arranged. Furthermore, the adjacent metal wires 1-n and 1-(n+1) are hooked with each other in such a manner that each first coil portion 1-(n+1)1a of the metal wire 1-(n+1) passes through each first coil portion 1-n1a of the metal wire 1-n, and each second coil portion 1-n1b of the metal wire 1-n passes through each second coil portion 1-(n+1)1b of the metal wire 1-(n+1). In other words, each second coil portion 1-(n+1)1b of the metal wire 1-(n+1) is hooked to each group of the adjacent first coil portions 1-n1a and 1-n1a of the metal wire 1-n, and each first coil portion 1-n1a of the metal wire 1-n is hooked to each group of the adjacent second coil portions 1-(n+1)n1b and 1-(n+1)n1b of the metal wire 1-(n+1). By knitting the metal wires 1-1, 1-2, ... in this way, the spring elasticity and repeated rebound resilience (rebound force maintenance) of the elastic pad 100 can be improved. Figure 3 In order to improve the readability of the figure, only five first coil parts 1-n1a and only four second coil parts 1-n1b are shown for each metal wire 1-n, but in the end, Figure 3 Those skilled in the art can appropriately determine the number of first coil portions 1-n1a, 1-n1a, ... and second coil portions 1-n1b, 1-n1b, ... of each metal wire 1-n according to the size of the metal mesh 10.

[0095] Each metal wire 1-n has a first end 1-ne and a second end 1-nf. The processing of the end of the metal wire 1 is not limited to a specific method.

[0096] In one embodiment, the first end 1-ne of each metal wire 1-n may be bonded to the first end 1-(n+1)e of the adjacent metal wire 1-(n+1), and the second end 1-nf of each metal wire 1-n may be bonded to the second end 1-(n+1)nf of the adjacent metal wire 1-(n+1). Figure 3The shown planar metal mesh 10-pre1 is a layer (hereinafter also referred to as a "unit layer 10-unit") formed by weaving metal wires 1-1, 1-2, 1-3, ... Figure 4 is a diagram schematically illustrating a metal mesh 10-pre1 of this method, Figure 4 (A) is a top view of the metal mesh 10-pre1. Figure 4 (B) is a front view of the metal mesh 10-pre1. Figure 4 Sometimes, Figures 2-3 The element annotations shown in Figures 2-3 The same reference numerals as those in the figure are used, and their description is omitted. Figure 4 As shown in (B), the metal mesh 10-pre1 is planar and has only one unit layer 10-unit. When the ends of the metal wires 1 are joined together, a known joining method such as welding, crimping, brazing, or joint connection can be used without particular limitation.

[0097] In another embodiment, the first end 1-(2k-1)e of the metal wire 1-(2k-1) (k=1, 2, ...) may be joined or continuous with the first end 1-(2k)e of the adjacent metal wire 1-(2k) (k=1, 2, ...), and the second end 1-(2k)f of the metal wire 1-(2k) (k=1, 2, ...) may be joined or continuous with the second end 1-(2k+1)f of the adjacent metal wire 1-(2k+1) (k=1, 2, ...). For example, Figure 3 In the embodiment, the first end 1-1e of the metal wire 1-1 is continuous with the first end 1-2e of the metal wire 1-2, and the second end 1-2f of the metal wire 1-2 is continuous with the second end 1-3f of the metal wire 1-3; the first end 1-3e of the metal wire 1-3 is continuous with the first end 1-4e of the metal wire 1-4, and the second end 1-4f of the metal wire 1-4 is continuous with the second end 1-5f (not shown) of the metal wire 1-5. According to the end processing of this method, a continuous metal wire (which can be a single wire or a wire bundle) can be used to weave a planar metal mesh 10-pre1 ( Figure 4 ) as a whole.

[0098] In another embodiment, the first end 1-ne of each metal wire 1-n may be joined to the second end 1-nf of the metal wire 1-n. According to this end treatment, a cylindrical metal mesh 10-cyl ( Figure 5 (A) Figure 5 (B)). Figure 5 It is a figure which schematically illustrates the cylindrical metal mesh 10-cyl and the metal mesh 10-pre2 obtained from the cylindrical metal mesh 10-cyl. Figure 5 (A) is a top view of a cylindrical metal mesh 10-cyl. Figure 5 (B) is a front view of the cylindrical metal mesh 10-cyl. Figure 5 Sometimes, Figures 2 to 4 The element annotations shown in Figures 2 to 4 The same reference numerals as those in the figure are omitted for explanation. Figure 5 The cylindrical metal mesh 10-cyl is flattened in the direction parallel to the paper surface (B) to obtain a metal mesh having two unit layers 10-unit (refer to Figure 3 . ) structure, planar metal mesh 10-pre2. Figure 5 (C) is a top view of the metal mesh 10-pre2. Figure 5 (D) is a front view of the metal mesh 10-pre2. Figure 5 As shown in (D), in the metal mesh 10-pre2, two unit layers 10-unit are continuous at the ends in the width direction of the weaving. Figure 5 In (D), for convenience of illustration, the unit layers 10-unit and 10-unit are described with a gap between them, but in reality, the two are in contact with each other.

[0099] In another embodiment, the first end 1-ne of each metal wire 1-n may be connected to the downstream side ( Figure 3 The second end 1-(n+1)f of the metal wire 1-(n+1) on the upper side of the paper is joined or continuous. Figure 3 In the embodiment, the first end 1-1e of the metal wire 1-1 is continuous with the second end 1-2f of the metal wire 1-2; the first end 1-2e of the metal wire 1-2 is continuous with the second end 1-3f of the metal wire 1-3; the first end 1-3e of the metal wire 1-3 is continuous with the second end 1-4f of the metal wire 1-4; the first end 1-4e of the metal wire 1-4 is continuous with the second end 1-5f (not shown) of the metal wire 1-5. According to the end treatment of this method, a cylindrical metal mesh 10-cyl is obtained as a whole (see Figure 5 (A) Figure 5 (B). According to this method, a continuous metal wire 1 (which can be a single wire or a wire bundle) can be used to weave a cylindrical metal mesh 10-cyl as a whole. The end treatment of this method can be performed, for example, by using a braiding machine equipped with a cylindrical mold. As described above, by flattening the cylindrical metal mesh 10-cyl along the radial direction of the cylinder, a metal mesh having two stacked unit layers 10-unit (see Figure 3 . ) structure, flat metal mesh 10-pre2 ( Figure 5(C) Figure 5 (D)).

[0100] By giving the metal mesh 10-pre1 or 10-pre2 a wave shape having an amplitude in the thickness direction of the metal mesh, the metal mesh 10 having spring elasticity in the thickness direction is obtained (see Figure 2 . ). When the corrugated shape is imparted to the planar metal mesh, a known method such as a punching process using a mold such as a corrugated roller can be used without particular limitation. Figure 2 The wave shape of the metal mesh 10 is preferably formed in a manner such that the ridges (ridge lines) R, R, ... of the wave shape intersect with the weaving direction (arrow W) of the metal mesh 10 when viewed from above. According to this embodiment, the formed wave shape is easily maintained for a long time.

[0101] The pitch λ of the wave shape formed on the metal mesh 10 (the distance between adjacent ridges (ridge lines) R when the metal mesh is viewed from above. Figure 2 (A). ) is preferably 10 mm to 30 mm, more preferably 14 mm to 16 mm. By making the spacing λ of the wave shape below the above upper limit, the pressure of the elastic pad pressing the electrode can be made more uniform over the entire surface of the electrode. In addition, by making the spacing λ of the wave shape above the above lower limit, it is easy to give the metal mesh 10 spring elasticity in the thickness direction.

[0102] The resilient force per unit area of ​​the elastic pad 100 when it is compressed and deformed by 50% is preferably 100 gf / cm 2 ~450gf / cm 2 , more preferably 150gf / cm 2 ~300gf / cm 2 . By making the rebound force per unit area of ​​the elastic pad 100 at 50% compression deformation be above the above lower limit, when the elastic pad 100 is used in an alkaline water electrolyzer, the zero gap structure can be maintained more stably even if the pressure in the electrolyzer fluctuates, and the surface pressure of the electrode clamping diaphragm can be further increased without damaging the uniformity of the surface pressure, and the proportion of the zero gap area in the electrode area can be further increased, thereby further improving the energy efficiency. In addition, by making the rebound force per unit area of ​​the elastic pad 100 at 50% compression deformation be below the above upper limit, the repeated rebound resilience is further improved, and sufficient rebound force is maintained during long-term use, making it easy to maintain the energy efficiency of the alkaline water electrolyzer at a high level for a long time. In this specification, the "50% compression deformation" of the elastic pad refers to compressing the elastic pad in the thickness direction in such a way that the thickness of the elastic pad becomes 50% of that before deformation.

[0103] When the elastic pad 100 is compressed and deformed by 50% twice, the rebound force per unit area during the second 50% compression deformation is preferably 40 gf / cm 2 More preferably, 50 gf / cm 2 By making the rebound force per unit area during the second 50% compression deformation be above the above lower limit, the repeated rebound resilience is maintained for a longer period of time, and the energy efficiency of the alkaline water electrolyzer can be easily maintained at a high level for a long period of time. In this specification, "repeated 50% compression deformation twice" of the elastic pad means that after the first 50% compression deformation, the compression force applied to the elastic pad is removed, the thickness of the elastic pad is fully naturally restored, and then the elastic pad is compressed and deformed in the thickness direction again so that the thickness of the elastic pad becomes 50% of the initial thickness (the thickness before the first 50% compression deformation).

[0104] In this specification, the method for measuring the rebound force per unit area of ​​the elastic pad at the first and second 50% compression deformations is as follows. Fig.18 and Fig.19 . Fig.18 (A) is a top view schematically illustrating a metal container 90. Fig.18 (B) is Fig.18 BB cross-sectional view of (A). The metal container 90 has a square bottom plate 91 and a wall plate 92 erected on the outer periphery of the bottom plate 91, and has an internal space 93 with a square cross-section of 150 mm in length and width. The depth of the internal space 93 is 10 mm or more. A test piece 94 formed by cutting an elastic pad into a square shape of 150 mm in length and width is arranged on the bottom plate 91 of the metal container 90. Fig.19 (A) schematically illustrates Fig.18 (B) is a cross-sectional view of a state where a test piece 94 is arranged on a bottom plate 91. A metal pressing plate 95 having a square shape and a length of 150 mm and a width of 150 mm is maintained parallel to the bottom plate 91 of the metal container 90, and is slowly lowered from the top of the metal container 90 toward the test piece 94. The time at which the pressing plate is lowered until the thickness of the test piece 94 becomes the initial thickness t is measured. init The rebound force at the time of 50% of the compression deformation (i.e., the rebound force at the first 50% compression deformation) is calculated. By dividing the measured rebound force by the area of ​​the test piece 94, the rebound force per unit area at the first 50% compression deformation can be calculated. Fig.19 (B) is a cross-sectional view schematically illustrating the positional relationship between the metal container 90, the test piece 94, and the pressing plate 95 before the pressing plate 95 contacts the test piece 94. Fig.19 (C) schematically illustrates the process of lowering the pressing plate until the thickness of the test piece 94 reaches the initial thickness t initThe cross-sectional view of the positional relationship among the metal container 90, the test piece 94 and the pressing plate 95 at the time when the metal container 90 is 50% of the test piece 94 and the pressing plate 95 are 50% of the test piece 94. Fig.19 The pressing plate 95 is held by the rod 96. Next, the pressing plate 95 is slowly lifted from the bottom of the metal container 90 until it is sufficiently away from the initial thickness t of the test piece. init Wait until the shape of the test piece has fully recovered. Fig.19 (D) is a cross-sectional view schematically illustrating a state in which the pressing plate 95 is lifted and the shape of the test piece 94 is fully restored. Fig.19 In (D), the thickness of the test piece 94 is restored to the initial thickness t init However, as long as the shape of the test piece 94 is fully restored, it is not necessary for the thickness of the test piece 94 to be restored to the initial thickness t init Even after sufficient time (eg, 10 minutes) has passed since the pressing plate 95 was lifted, the thickness of the test piece 94 has not recovered to the initial thickness t init In the case of the test piece 94, a second 50% compression test is performed in this state. After the shape of the test piece 94 is restored, the pressing plate is slowly lowered again while being maintained parallel to the bottom surface of the metal container, and the rebound force (i.e., the rebound force at the second 50% compression deformation) is measured when the pressing plate is lowered to the point where the thickness of the test piece becomes 50% of the initial thickness (thickness before the first compression deformation). By dividing the measured rebound force by the area of ​​the test piece 94, the rebound force per unit area at the second 50% compression deformation can be calculated. Fig.19 (E) is a cross-sectional view schematically illustrating the positional relationship between the metal container 90, the test piece 94, and the pressing plate 95 during the second 50% compression deformation. The load sensor is used to detect the contact between the pressing plate and the test piece and to measure the rebound force applied from the test piece to the pressing plate. During the entire test, the pressing plate 95 is maintained parallel to the bottom plate 91 of the metal container 90.

[0105] The thickness of the elastic pad 100 (thickness before compression deformation) t (refer to Figure 2 . ) is preferably 7.5mm to 10mm. When the thickness t of the elastic pad is within the above range, the resilience of the elastic pad during compression deformation is within the preferred range. In this specification, the thickness of the elastic pad does not refer to the thickness of the unit layer 10-unit of the metal mesh itself, but refers to the maximum height of the elastic pad from the surface of the table when the metal mesh is shaped into a wavy shape (and randomly stacked) to become an elastic pad and the elastic pad is laid on a flat table.

[0106] In the above description of the present invention, when the metal mesh 10 (see Figure 2(A). ), an elastic pad 100 in which the wave shape imparted to the metal mesh 10 is a triangular wave is cited as an example, but the present invention is not limited to this method. For example, the elastic pad 100 in which the wave shape imparted to the metal mesh is a sine wave, a sawtooth wave, a square wave, etc. can also be set. In addition, for example, these waveforms can also be deformed from an ideal sine wave. For example, the elastic pad in which the wave shape imparted to the metal mesh is a deformed sine wave, a deformed triangular wave, a deformed sawtooth wave, a deformed square wave, etc. can also be set.

[0107] In the above description of the present invention, when the metal mesh 10 (see Figure 2 ) is shown as an example, in which the ridges (ridge lines) R of the wave shape formed on the metal mesh 10 are expressed as straight lines. However, the present invention is not limited to this embodiment. Figure 6 and Figure 7 are top views schematically illustrating elastic pads 200 and 300 for an alkaline water electrolyzer according to another embodiment (hereinafter sometimes referred to as "elastic pad 200" and "elastic pad 300", respectively). Figure 2 The corresponding figure of (A). Figure 6 and Figure 7 Sometimes, Figures 2 to 5 The element annotations shown in Figures 2 to 5 For example, the elastic pad 200 ( Figure 6 ). In addition, for example, the elastic pad 300 ( Figure 7 ).

[0108] In the above description of the present invention, the elastic pads 100, 200, and 300 are exemplified as being composed of one metal mesh, but the present invention is not limited to this embodiment. For example, the elastic pad may be formed by laminating two or more metal meshes. Figure 8 FIG. 4 is a diagram schematically illustrating an elastic pad 400 for an alkaline water electrolyzer (hereinafter also referred to as “elastic pad 400 ”) according to another embodiment of the present invention. Figure 8 Sometimes, Figures 2 to 7 The element annotations shown in Figures 2 to 7 The same reference numerals as those in the figure are used, and their description is omitted. The elastic pad 400 has a structure in which two metal meshes 10a and 10b are stacked. Figure 8(A) is a top view of the elastic pad 400, showing only the metal mesh 10a on the upper layer side. Figure 8 (B) is a front view of the elastic pad 400, showing both the metal mesh 10a on the upper layer side and the metal mesh 10b on the lower layer side. Figure 8 (C) is Figure 8 The cross-sectional view taken along the arrow CC of (B) shows only the metal mesh 10b on the lower layer side. The metal meshes 10a and 10b are the same as the metal mesh 10 described above. However, the metal mesh 10b on the lower layer side is oriented 90° away from the metal mesh 10a on the upper layer side when viewed from above. Fig. 9 is a perspective top view of the elastic pad 400, which is Figure 8 The corresponding figure of (A). Fig. 9 Sometimes, Figures 2 to 8 The element annotations shown in Figures 2 to 8 The same reference numerals as those in the figure are used, and their description is omitted. Fig. 9 In the figure, only the ridges (ridge lines) R, R, ... of the metal meshes 10a and 10b are shown. Fig. 9 In FIG. 1 , ridges (ridge lines) R, R, ... of the metal mesh 10a are indicated by solid lines, and ridges (ridge lines) R, R, ... of the metal mesh 10b are indicated by dotted lines.

[0109] like Figure 8 and Fig. 9 As shown, in the elastic pad 400, two adjacent metal meshes 10a and 10b are stacked in such a manner that the ridges (ridge lines) R, R, ... formed in a wave shape on one metal mesh intersect with the ridges (ridge lines) R, R, ... formed in a wave shape on the other metal mesh when viewed from above. In this way, by stacking a plurality of metal meshes in such a manner that the ridges (ridge lines) formed in a wave shape on two adjacent metal meshes intersect when viewed from above, the ridges R, R, ... formed in a wave shape on one metal mesh (the metal mesh 10b on the lower layer side) support the valleys V, V, ... formed in a wave shape on the other metal mesh (the metal mesh 10a on the upper layer side) (see FIG. 1 ). Figure 2 (D). Thus, the spring elasticity of the metal mesh on the upper layer side and the spring elasticity of the metal mesh on the lower layer side can be made to work in series. In addition, even if a deviation occurs between the metal mesh 10a on the upper layer side and the metal mesh 10b on the lower layer side due to vibration or the like, the spring elasticity of the elastic pad 400 as a whole can be suppressed from becoming uneven by embedding the wavy edges (ridges) R, R, ... formed on the metal mesh 10b on the lower layer side into the recessed portion on the inner side of the wavy edges (ridges) R, R, ... formed on the metal mesh 10a on the upper layer side.

[0110] In the elastic pad 400, the adjacent metal meshes 10a, 10b are joined together at least at the peripheral edge. When joining the adjacent metal meshes, any known joining method such as welding, soldering, pinning, or connecting with resin wire or metal wire can be used without particular limitation.

[0111] The thickness of the elastic pad 400 (thickness before compression deformation) t (see Figure 8 (B). ), the rebound force per unit area at 50% compression deformation and the rebound force per unit area at the second 50% compression deformation when the 50% compression deformation is repeated twice, and the preferred method of the spacing λ of the wave shape of the metal mesh 10 of the elastic pad 400 is as described above for the elastic pad 100.

[0112] From the viewpoint of making the pressure of the elastic pad pressing the electrode more uniform over the entire surface of the electrode in the alkaline water electrolysis cell, the pitch λ (the interval between adjacent ridges (ridge lines) R when the metal mesh is viewed from above) of the wave shape formed on the metal mesh is Figure 2 (A) Figure 6 , Figure 7 , Figure 8 (A) and Figure 8 (C). ) is preferably narrow within a range that can ensure spring elasticity. However, it is not necessarily easy to give a metal mesh a wave shape having both a narrow spacing λ (wavelength) and a large amplitude. According to the method of stacking multiple metal meshes like the elastic pad 400, by stacking metal meshes shaped into a wave shape with a narrow spacing λ and a relatively small amplitude, an elastic pad of the desired thickness can be obtained, thereby obtaining a thicker elastic pad, and it is also easy to narrow the spacing of the wave shape, and it is easy to improve the repeated resilience of the elastic pad, thereby maintaining the energy efficiency of the alkaline water electrolyzer at a high level for a long time. In addition, according to the method of stacking multiple metal meshes, a rebound force that cannot be obtained with a single metal mesh can also be obtained. In the elastic pad 400, multiple identical metal meshes 10 are stacked, but multiple metal meshes with different rebound forces can also be stacked. The elastic pad using the method of stacking multiple metal meshes with different rebound forces can freely adjust the rebound force of the elastic pad.

[0113] The thickness t of the metal mesh 10 alone unit In the elastic pad 100, it is equal to the thickness t of the elastic pad 100 as a whole, and in the elastic pad 400, it is equal to t / 2, wherein the thickness of the elastic pad 400 as a whole is taken as t. The thickness t of the metal mesh alone unit The ratio t to the pitch λ of the wave shape formed on the metal mesh unit / λ (dimensionless number) is preferably 0.25 to 1.00, more preferably 0.46 to 0.71. unit / λ is greater than the above lower limit, it is easy to improve the resilience of the elastic pad as a whole. unit When / λ is equal to or less than the above upper limit, the repeated rebound resilience of the elastic pad can be easily improved.

[0114] In the above description of the present invention, an elastic pad 400 is exemplified by stacking a plurality of metal meshes 10 having straight edges (ridges) R, R, ... when viewed from above, but the present invention is not limited to this embodiment. For example, a plurality of metal meshes 210 ( Figure 6 ), the ridges (ridge lines) R, R, ... appear as sawtooth-shaped metal mesh 310 ( Figure 7 In such a case, the metal meshes are preferably stacked in such a manner that, for each group of two adjacent metal meshes, the wavy ridges (ridge lines) R, R, ... formed on one metal mesh intersect with the wavy ridges (ridge lines) R, R, ... formed on the other metal mesh when viewed from above.

[0115] Fig.10 This is a perspective top view of an elastic pad 500 for an alkaline water electrolyzer (hereinafter also referred to as "elastic pad 500") according to another embodiment of the present invention. Fig. 9 The corresponding figure. Fig.10 Sometimes, Figures 2 to 9 The element annotations shown in Figures 2 to 9 The same reference numerals as those in the figure are omitted for explanation. The elastic pad 500 is formed by placing two metal meshes 210 (see Figure 6 . ) are stacked together to form an elastic pad. Fig.10 In the figure, only the ridges (ridge lines) R, R, ... of the metal meshes 210, 210 are shown. Fig.10 In FIG. 1 , the edges (ridges) R, R, ... of one metal mesh 210 are represented by solid lines, and the edges (ridges) R, R, ... of another metal mesh 210 are represented by dotted lines. Fig.10 As shown, in the elastic pad 500, two metal meshes 210 are stacked in such a manner that the weaving directions of the metal meshes are oriented in different directions from each other, and in a group of two adjacent metal meshes 210, 210, the wavy edges (ridges) R, R, ... shaped on one metal mesh intersect with the wavy edges (ridges) R, R, ... shaped on the other metal mesh when viewed from above.

[0116] Fig.11 is a perspective top view of an elastic pad 600 for an alkaline water electrolyzer (hereinafter also referred to as "elastic pad 600") according to another embodiment. Fig. 9 The corresponding figure. Fig.11 Sometimes, Figures 2 to 10 The element annotations shown in Figures 2 to 10 The elastic pad 600 is formed by placing two metal meshes 310 (see Figure 7 . ) are stacked together to form an elastic pad. Fig.11 In the figure, only the ridges (ridge lines) R, R, ... of the metal meshes 310, 310 are shown. Fig.11 In FIG. 1 , the edges (ridges) R, R, ... of one metal mesh 310 are represented by solid lines, and the edges (ridges) R, R, ... of another metal mesh 310 are represented by dotted lines. Fig.11 As shown, in the elastic pad 600, by stacking two metal meshes 310 arranged in such a manner that the weaving directions of the metal meshes are oriented in different directions from each other, in a group of two adjacent metal meshes 210, 210, the wavy edges (ridges) R, R, ... shaped on one metal mesh intersect with the wavy edges (ridges) R, R, ... shaped on the other metal mesh when viewed from above.

[0117] In the above description of the present invention, elastic pads 400, 500, and 600 having two stacked metal meshes are cited as examples, but the present invention is not limited to this embodiment. For example, an elastic pad having three or more stacked metal meshes can also be provided. The number of stacked metal meshes can preferably be 2 to 8, and more preferably 2 to 4. In addition, in a metal pad having three or more stacked metal meshes, the stacking of the metal meshes is also preferably performed in such a way that, for each group of metal meshes consisting of two adjacent metal meshes, the wavy edges (ridges) R, R, ... shaped on one metal mesh and the wavy edges (ridges) R, R, ... shaped on another metal mesh intersect when viewed from above.

[0118] In the above description of the present invention, the elastic pads 400, 500, and 600 are provided as examples, wherein the plurality of stacked metal meshes are provided, and each group of adjacent and stacked metal meshes is integrated by being joined at least at the peripheral edge portion, but the present invention is not limited to this embodiment. For example, the elastic pad may be provided in a manner in which the plurality of stacked metal meshes are held as one by joining the peripheral edge portion of each metal mesh to the flange portion (described later) of the electrolytic element or the current collector (described later).

[0119] In the above description of the present invention, as an example, the elastic pads 100, 200, 300, 400, 500, 600 having the wire meshes 10, 210, 310 knitted with metal wires are given, but the present invention is not limited to this mode. For example, it is also possible to adopt a mode of an elastic pad for an alkaline water electrolysis cell having a wire mesh woven or braided with metal wires by a weaving or braiding method other than knitting. When a wire mesh is woven or braided with metal wires, the weaving and braiding methods are not particularly limited as long as the wire mesh can have spring elasticity in the thickness direction. As such other weaving and braiding methods, reverse knitting (Japanese: 裏メリヤス編み), rib knitting, etc. can be cited.

[0120] <2. Alkaline water electrolysis cell>

[0121] Fig.12 is a cross-sectional view schematically showing an alkaline water electrolysis cell 1000 (hereinafter also referred to as "electrolysis cell 1000".) according to an embodiment of the present invention. In Fig.12 therein, sometimes elements already shown in Figures 2 to 11 are labeled with the same reference numerals as those in Figures 2 to 11 and the description thereof is omitted. The electrolysis cell 1000 is an alkaline water electrolysis cell having the elastic pad 100 for an alkaline water electrolysis cell described above (see Figure 2 .). As Fig.12 shown, the electrolysis cell 1000 includes: an anode-side frame body 51, which includes a conductive back partition wall 51a and a flange portion 51b liquid-tightly bonded to the entire peripheral portion of the back partition wall 51a, and defines an anode chamber A; a cathode-side frame body 52, which includes a conductive back partition wall 52a and a flange portion 52b liquid-tightly bonded to the entire peripheral portion of the back partition wall 52a, and defines a cathode chamber C; an ion-permeable diaphragm 1010, which is disposed between the anode-side frame body 51 and the cathode-side frame body 52; a set of gaskets 21, 22, which are respectively disposed between the diaphragm 1010 and the flange portion 51b of the anode-side frame body 51 and between the diaphragm 1010 and the flange portion 52b of the cathode-side frame body 52, and sandwich the peripheral portion of the diaphragm 1010; conductive rib portions 61, 61,... (hereinafter also referred to as "conductive rib portions 61".), which are突出地设置 from the back partition wall 51a of the anode-side frame body 51; conductive rib portions 62, 62,... (hereinafter also referred to as "conductive rib portions 62".), which are突出地设置 from the back partition wall 52a of the cathode-side frame body 52; a current collector 72, which is held by the conductive rib portions 62; a conductive elastic pad (first elastic pad) 100 (see Figure 2. ), which is held by the current collector 72; the cathode (first electrode) 30, which is arranged between the elastic pad 100 and the diaphragm 1010; and the anode (second electrode) 40, which is held by the conductive rib 61. In this way, the electrolytic cell 1000 includes: an anode chamber A, which accommodates the anode 40 and produces oxygen; a cathode chamber C, which accommodates the cathode 30 and produces hydrogen; an ion-permeable diaphragm 1010, which divides the anode chamber A and the cathode chamber C; and a first elastic pad 100, which is an elastic pad for an alkaline water electrolysis cell of the present invention. In the electrolytic cell 1000, the cathode (first electrode) 30 is a flexible porous plate (first porous plate), and the anode (second electrode) 40 is a rigid porous plate (second porous plate).

[0122] In the electrolytic cell 1000 , the cathode (first electrode) 30 is pressed toward the anode (second electrode) 40 by the elastic pad (first elastic pad) 100 , thereby realizing a zero gap structure in which the diaphragm 1010 is sandwiched between the cathode (first electrode) 30 and the anode (second electrode) 40 .

[0123] As anode side frame 51 and cathode side frame 52, as long as anode chamber A and cathode chamber C can be defined respectively, known frames used in alkaline water electrolyzers can be used without particular restrictions. Anode side frame 51 includes a conductive back partition wall 51a and a flange 51b that is liquid-tightly combined with the entire peripheral portion of back partition wall 51a. Similarly, cathode side frame 52 also includes a conductive back partition wall 52a and a flange 52b that is liquid-tightly combined with the entire peripheral portion of back partition wall 52a. Back partition walls 51a, 52a divide adjacent electrolysis units from each other, and make adjacent electrolysis units electrically connected in series. Flange 51b and back partition wall 51a, diaphragm 1010 and gasket 21 define the anode chamber, and flange 52b and back partition wall 52a, diaphragm 1010 and gasket 22 define the cathode chamber. The flanges 51b and 52b have shapes corresponding to the gaskets 21 and 22. That is, when the gaskets 21 and 22 and the diaphragm 1010 are clamped by the anode side frame 51 and the cathode side frame 52, the flange 51b of the anode side frame 51 contacts the gasket 21 without a gap, and the flange 52b of the cathode side frame 52 contacts the gasket 22 without a gap. In addition, the flange 51b has: an anolyte supply flow path, which supplies anolyte to the anode chamber A; and an anolyte recovery flow path, which recovers the anolyte and the gas generated at the anode from the anolyte A, but in Fig.12. In addition, the flange portion 52b is provided with: a cathode liquid supply flow path that supplies cathode liquid to the cathode chamber C; and a cathode liquid recovery flow path that recovers cathode liquid and gas generated at the cathode from the cathode chamber C. As the material of the back partition walls 51a and 52a, a rigid conductive material having alkali resistance can be used without particular limitation. Examples of such materials include single metals such as nickel and iron; stainless steels such as SUS304, SUS310, SUS310S, SUS316, and SUS316L; and metal materials obtained by plating the above materials with nickel. As the material of the flange portions 51b and 52b, a rigid material having alkali resistance can be used without particular limitation. Examples of such materials include single metals such as nickel and iron; stainless steels such as SUS304, SUS310, SUS310S, SUS316, and SUS316L; and metal materials obtained by plating the above materials with nickel; and non-metallic materials such as reinforced plastics. The back partition wall 51a and the flange 51b of the anode side frame 51 may be joined by welding, bonding, etc., or may be formed integrally from the same material. Similarly, the back partition wall 52a and the flange 52b of the cathode side frame 52 may be joined by welding, bonding, etc., or may be formed integrally from the same material. Fig.12 Only a single electrolytic unit (electrolytic cell 1000) is shown in FIG. 1 , but the flange portion 51b of the anode side frame body 51 may also extend toward the side opposite to the back partition wall 51a (at Fig.12 The flange portion 52b of the cathode side frame 52 extends to the side opposite to the back partition wall 52a (on the right side of the paper) and defines the cathode chamber of the adjacent electrolytic unit together with the back partition wall 51a. In addition, the flange portion 52b of the cathode side frame 52 also extends to the side opposite to the back partition wall 52a (on the right side of the paper). Fig.12 The back partition wall 52 extends from the left side of the paper and, together with the back partition wall 52a, defines the anode chamber of the adjacent electrolytic unit.

[0124] As conductive ribs 61 and conductive ribs 62, the known conductive ribs used in alkaline water electrolyzers can be used without particular restrictions. In electrolyzer 1000, conductive ribs 61 are set up from the back side partition wall 51a of anode side frame 51, and conductive ribs 62 are set up from the back side partition wall 52a of cathode side frame 52. As long as conductive ribs 61 can fix and maintain anode 40 relative to anode side frame 51, the shape, quantity and configuration of conductive ribs 61 are not particularly limited. In addition, as long as conductive ribs 62 can fix and maintain collector 72 relative to cathode side frame 52, the shape, quantity and configuration of conductive ribs 62 are not particularly limited either. As the material of the conductive ribs 61 and the conductive ribs 62, a rigid conductive material with alkali resistance can be used without particular restrictions. Examples of such materials include single metals such as nickel and iron; stainless steels such as SUS304, SUS310, SUS310S, SUS316, and SUS316L; and metals made by nickel plating the above substances.

[0125] As the current collector 72, a known current collector used in an alkaline water electrolyzer can be used without particular limitation. For example, an expanded alloy or stamped metal made of a rigid conductive material having alkali resistance can be preferably used. Examples of the material of the current collector 72 include single metals such as nickel and iron; stainless steels such as SUS304, SUS310, SUS310S, SUS316, and SUS316L; and metals obtained by plating the above materials with nickel. When the current collector 72 is held on the conductive rib 62, a known method such as welding or pinning can be used without particular limitation.

[0126] The elastic pad 100 is as described above. When the elastic pad 100 is held on the current collector 72, a known method such as welding, pinning, and bolting can be adopted without particular limitation.

[0127] As the diaphragm 1010, a known ion-permeable diaphragm used in a zero-gap electrolyzer for alkaline water electrolysis can be used without particular limitation. The diaphragm 1010 preferably has low gas permeability, low electrical conductivity, and high strength. Examples of the diaphragm 1010 include porous membranes with ion permeability such as a porous membrane composed of asbestos and / or modified asbestos, a porous membrane using a polysulfone polymer, a cloth using polyphenylene sulfide fiber, a fluorine-based porous membrane, and a porous membrane using a mixed material containing both an inorganic material and an organic material.

[0128] As the gaskets 21 and 22, any gaskets that can be used in an electrolytic cell for alkaline water electrolysis and have electrical insulation properties can be used without particular limitation. Fig.12, the cross section of the gasket 21, 22 is shown in FIG. The gasket 21, 22 has a flat shape, clamping the peripheral edge of the diaphragm 1010, and on the other hand, the gasket 21, 22 is clamped between the flange 51b of the anode side frame 51 and the flange 52b of the cathode side frame 52. The gasket 21, 22 is preferably formed by an elastomer with alkali resistance. As examples of materials for the gaskets 21, 22, natural rubber (NR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), silicone rubber (SR), ethylene-propylene rubber (EPT), ethylene-propylene diene rubber (EPDM), fluororubber (FR), isobutylene-isoprene rubber (IIR), polyurethane rubber (UR), chlorosulfonated polyethylene rubber (CSM) and other elastomers can be cited. In addition, when using a gasket material that does not have alkali resistance, a material layer with alkali resistance can also be provided on the surface of the gasket material by coating, etc.

[0129] As the cathode (first electrode) 30, a cathode having a flexible porous plate, which is a well-known hydrogen generation cathode used in a zero-gap electrolyzer for alkaline water electrolysis, can be used without particular limitation. The cathode 30 generally comprises a conductive substrate and a catalyst layer covering the surface of the substrate. As the conductive substrate of the cathode 30, for example, nickel, nickel alloy, stainless steel, mild steel, nickel alloy, or a material made by nickel plating on the surface of stainless steel or mild steel can be preferably used. As the catalyst layer of the cathode 30, a noble metal oxide, nickel, cobalt, molybdenum, or manganese, or oxides of the above substances, or a coating composed of noble metal oxides can be preferably used. As the cathode 30 having a flexible porous plate, a porous plate having a flexible conductive substrate (for example, a metal mesh woven (or braided) by metal wires, a thinner stamping metal, etc.) and the above catalyst layer can be used. The area of ​​one hole of the cathode 30 having a flexible porous plate is preferably 0.05 mm 2 ~2.0mm 2 , more preferably 0.1 mm 2 ~0.5mm 2. The opening ratio of the cathode 30, which is a flexible porous plate, is preferably 20% or more relative to the area of ​​the current-carrying surface, and more preferably 20 to 50%. The bending flexibility of the cathode 30, which is a flexible porous plate, is preferably 0.05 mm / g or more, and more preferably 0.1 mm / g to 0.8 mm / g. In addition, in the present specification, the bending flexibility refers to the value obtained by dividing the bending amplitude (mm) of a square sample with a longitudinal length of 10 mm and a transverse length of 10 mm by the load (g) when a certain load is applied downward to the other side opposite to the fixed side, and fixing the other side of the sample in a horizontal manner. That is, the bending flexibility is a parameter that represents the opposite property of the bending rigidity. The bending flexibility can be adjusted according to the material and thickness of the porous plate, the weaving method (or braiding method) of the metal wire constituting the metal mesh in the case of a metal mesh, etc. The cathode 30 can be fixed to the collector 72 or to the elastic pad 100. When the cathode 30 is fixed to the current collector 72 or the elastic pad 100, for example, a known method such as welding, pin fixing, bolt fixing, etc. can be adopted without particular limitation. In addition, for example, the cathode 30 can also be fixed by folding the peripheral edge portion of the cathode 30 into the peripheral end portion of the current collector 72. When fixing the cathode 30, it is preferable to fix the cathode 30 in a manner that does not impair the resilience of the elastic pad 100.

[0130] As the anode (second electrode) 40, a known anode for oxygen generation, which is a rigid porous plate used in a zero-gap electrolyzer for alkaline water electrolysis, can be used without particular limitation. The anode 40 usually comprises a conductive substrate and a catalyst layer covering the surface of the substrate. The catalyst layer is preferably porous. As the conductive substrate of the anode 40, for example, nickel iron, vanadium, molybdenum, copper, silver, manganese, platinum group elements, graphite, or chromium or a combination of the above substances can be used. In the anode 40, a conductive substrate composed of nickel can be preferably used. The catalyst layer contains nickel as an element. The catalyst layer preferably contains nickel oxide, metallic nickel, or nickel hydroxide, or a combination of the above substances, and may also contain an alloy of nickel and one or more other metals. The catalyst layer is particularly preferably composed of metallic nickel. In addition, the catalyst layer may also contain chromium, molybdenum, cobalt, tantalum, zirconium, aluminum, zinc, platinum group elements, or rare earth elements, or a combination of the above substances. The surface of the catalyst layer may also contain rhodium, palladium, iridium, or ruthenium as an additional catalyst, or a combination of these substances. As the anode 40 of the rigid porous plate, a porous plate having a rigid conductive substrate (such as an expansion alloy, etc.) and the above-mentioned catalyst layer can be used. When the anode 40 is held on the conductive rib 61, known methods such as welding, pin fixing, and bolt fixing can be adopted without particular limitation.

[0131] In the electrolytic cell 1000, the cathode 30 is pressed toward the anode 40 by the elastic pad 100 of the present invention, so that the surface pressure of the anode 40 and the cathode 30 holding the diaphragm 1010 can be increased without damaging the uniformity of the surface pressure, and the proportion of the zero gap area in the electrode area can be increased. Thus, the operating voltage can be reduced and the energy efficiency can be improved.

[0132] In the electrolytic cell 1000, the surface pressure at which the cathode (first electrode) 30 is pressed toward the anode (second electrode) 40 is preferably 100 gf / cm 2 ~450gf / cm 2 , more preferably 150gf / cm 2 ~300gf / cm 2 . When the surface pressure is above the above lower limit, the zero gap structure can be maintained more stably even if the pressure in the electrolytic cell fluctuates, and the operating voltage can be further reduced and the energy efficiency can be further improved. In addition, when the surface pressure is below the above upper limit, the repeated rebound resilience is further improved, and sufficient rebound force is maintained during long-term use, making it easy to maintain the energy efficiency of the alkaline water electrolyzer at a high level for a long time.

[0133] In the above description of the present invention, an alkaline water electrolyzer 1000 is cited as an example in which the cathode (first electrode) 30 is a flexible porous plate and is pressed toward the anode (second electrode) 40 by the first elastic pad 100, but the present invention is not limited to this embodiment. For example, it is also possible to set the alkaline water electrolyzer in which the anode 40 is a flexible porous plate and is pressed toward the cathode 30 by the first elastic pad 100. Fig.13 FIG. 2 is a cross-sectional view schematically illustrating an alkaline water electrolysis cell 2000 (hereinafter also referred to as “electrolysis cell 2000”) according to another embodiment of the present invention. Fig.13 Sometimes, Figures 2 to 12 The element annotations shown in Figures 2 to 12 The same reference numerals as those in the figure are used, and their description is omitted. Fig.13As shown, the electrolytic cell 2000 comprises: an anode side frame 51, which includes a conductive back partition wall 51a and a flange portion 51b that is liquid-tightly combined with the entire peripheral portion of the back partition wall 51a, and defines an anode chamber A; a cathode side frame 52, which includes a conductive back partition wall 52a and a flange portion 52b that is liquid-tightly combined with the entire peripheral portion of the back partition wall 52a, and defines a cathode chamber C; an ion-permeable diaphragm 1010 that is arranged between the anode side frame 51 and the cathode side frame 52; a set of gaskets 21, 2 2, which are respectively arranged between the diaphragm 1010 and the flange portion 51b of the anode side frame 51 and between the diaphragm 1010 and the flange portion 52b of the cathode side frame 52, and sandwich the peripheral portion of the diaphragm 1010; conductive ribs 61, 61, ..., which are protrudingly provided from the back partition wall 51a of the anode side frame 51; conductive ribs 62, 62, ..., which are protrudingly provided from the back partition wall 52a of the cathode side frame 52; a collector 71, which is held by the conductive ribs 61; a conductive elastic pad (first elastic pad) 100 (refer to Figure 2 . ), which is held by the current collector 71; the anode (first electrode) 2040, which is arranged between the elastic pad 100 and the diaphragm 1010; and the cathode (second electrode) 2030, which is held by the conductive rib 62. In this way, the electrolytic cell 2000 includes: an anode chamber A, which accommodates the anode 2040 and produces oxygen; a cathode chamber C, which accommodates the cathode 2030 and produces hydrogen; an ion-permeable diaphragm 1010, which divides the anode chamber A and the cathode chamber C; and a first elastic pad 100, which is an elastic pad for an alkaline water electrolysis cell of the present invention. In the electrolytic cell 2000, the anode (first electrode) 2040 is a flexible porous plate (first porous plate), and the cathode (second electrode) 2030 is a rigid porous plate (second porous plate).

[0134] In the electrolytic cell 2000 , the anode (first electrode) 2040 is pressed toward the cathode (second electrode) 2030 by the elastic pad (first elastic pad) 100 , thereby realizing a zero gap structure in which the diaphragm 1010 is sandwiched between the anode (first electrode) 2040 and the cathode (second electrode) 2030 .

[0135] As the current collector 71, a known current collector used in an alkaline water electrolyzer can be used without particular limitation. For example, an expanded alloy, a stamped metal, a mesh, etc. made of a rigid conductive material having alkali resistance can be preferably used. Examples of the material of the current collector 71 include single metals such as nickel and iron; stainless steels such as SUS304, SUS310, SUS310S, SUS316, and SUS316L; and metals obtained by plating the above materials with nickel. When the current collector 71 is held on the conductive rib 61, a known method such as welding or pinning can be used without particular limitation.

[0136] The elastic mat 100 is as described above. When the elastic mat 100 is held on the current collector 71 , a known method such as welding or pinning can be adopted without particular limitation.

[0137] As the anode (first electrode) 2040, an anode for alkaline water electrolysis that is the same as the anode 40 described above and is a flexible porous plate can be used without particular limitation. As the anode 2040 that is a flexible porous plate, a porous plate having a flexible conductive substrate (e.g., a metal mesh woven (or braided) from metal wires, a thinner stamped metal, etc.) and the above-mentioned catalyst layer can be used. The area of ​​one hole of the anode 2040 that is a flexible porous plate is preferably 0.05 mm 2 ~2.0mm 2 , more preferably 0.1 mm 2 ~0.5mm 2 . The opening ratio of the anode 2040, which is a flexible porous plate, is preferably 20% or more, more preferably 20 to 50% relative to the area of ​​the current-carrying surface. The bending softness of the anode 2040, which is a flexible porous plate, is preferably 0.05 mm / g or more, more preferably 0.1 mm / g to 0.8 mm / g. The anode 2040 can be fixed to the collector 71 or the elastic pad 100. When fixing the anode 2040 to the collector 71 or the elastic pad 100, for example, known methods such as welding, pin fixing, and bolt fixing can be used without particular restrictions. In addition, for example, the anode 2040 can also be fixed by folding the peripheral edge portion of the anode 2040 into the peripheral end portion of the collector 71. When fixing the anode 2040, it is preferred to fix the anode 2040 in a manner that does not damage the resilience of the elastic pad 100.

[0138] As the cathode (second electrode) 2030, the cathode for alkaline water electrolysis that is the same as the cathode 30 described above and is a rigid porous plate can be used without particular limitation. As the cathode 30 that is a rigid porous plate, a porous plate having a rigid conductive substrate (e.g., an expansion alloy, etc.) and the above-mentioned catalyst layer can be used. When the cathode 2030 is held on the rib 62, a known method such as welding, pin fixing, bolt fixing, etc. can be used without particular limitation.

[0139] In the electrolytic cell 2000, the anode 2040 is pressed toward the cathode 2030 by the elastic pad 100 of the present invention, so that the surface pressure of the anode 2040 and the cathode 2030 holding the diaphragm 1010 can be increased without damaging the uniformity of the surface pressure, and the proportion of the zero gap area in the electrode area can be increased. Thus, the operating voltage can be reduced and the energy efficiency can be improved.

[0140] In the electrolytic cell 2000, the surface pressure at which the anode (first electrode) 2040 is pressed toward the cathode (second electrode) 2030 is preferably 100 gf / cm 2 ~450gf / cm 2 , more preferably 150gf / cm 2 ~300gf / cm 2 . When the surface pressure is above the above lower limit, the zero gap structure can be maintained more stably even if the pressure in the electrolytic cell fluctuates, and the operating voltage can be further reduced and the energy efficiency can be further improved. In addition, when the surface pressure is below the above upper limit, the repeated rebound resilience is further improved, and sufficient rebound force is maintained during long-term use, making it easy to maintain the energy efficiency of the alkaline water electrolyzer at a high level for a long time.

[0141] In the above description of the present invention, the alkaline water electrolyzer 1000 in which the second electrode (anode) 40 of the rigid porous plate is held by the conductive rib 61 and the alkaline water electrolyzer 2000 in which the second electrode (cathode) 2030 of the rigid porous plate is held by the conductive rib 62 are cited as examples, but the present invention is not limited to this method. For example, it is also possible to set the alkaline water electrolyzer in which the second electrode of the rigid porous plate is pressed toward the first electrode by the second elastic pad as the elastic pad for the alkaline water electrolyzer of the present invention. Fig.14 FIG. 1 is a cross-sectional view schematically illustrating an alkaline water electrolysis cell 3000 (hereinafter also referred to as “electrolysis cell 3000”) according to another embodiment of the present invention. Fig.14 Sometimes, Figures 2 to 13 Elements identical to those already shown in Figures 2 to 13 The same reference numerals as those in the figure are used, and their description is omitted. Fig.14As shown, the electrolytic cell 3000 comprises: an anode side frame 51, which includes a conductive back partition wall 51a and a flange portion 51b that is liquid-tightly combined with the entire peripheral portion of the back partition wall 51a, and defines an anode chamber A; a cathode side frame 52, which includes a conductive back partition wall 52a and a flange portion 52b that is liquid-tightly combined with the entire peripheral portion of the back partition wall 52a, and defines a cathode chamber C; an ion-permeable diaphragm 1010, which is arranged between the anode side frame 51 and the cathode side frame 52; a group of gaskets 21, 22, which are respectively arranged between the diaphragm 1010 and the flange portion 51b of the anode side frame 51 and between the diaphragm 1010 and the flange portion 52b of the cathode side frame 52, and sandwich the diaphragm 1010. 010; conductive ribs 61, 61, ..., which are protruding from the back partition wall 51a of the anode side frame 51; conductive ribs 62, 62, ..., which are protruding from the back partition wall 52a of the cathode side frame 52; a collector 72, which is held by the conductive ribs 62; a conductive elastic pad (first elastic pad) 100a, which is held by the collector 72; a cathode (first electrode) 30, which is arranged between the first elastic pad 100a and the diaphragm 1010; a collector 71, which is held by the conductive ribs 61; a conductive elastic pad (second elastic pad) 100b, which is held by the collector 71; and an anode (second electrode) 40, which is arranged between the second elastic pad 100b and the diaphragm 1010. The first elastic pad 100a and the second elastic pad 100b are similar to the elastic pad 100 for the alkaline water electrolyzer of the present invention described above (see Figure 2 . ) are the same. As such, the electrolytic cell 3000 comprises: an anode chamber A that accommodates the anode 40 and generates oxygen; a cathode chamber C that accommodates the cathode 30 and generates hydrogen; an ion-permeable diaphragm 1010 that separates the anode chamber A from the cathode chamber C; a first elastic pad 100a that is an elastic pad for an alkaline water electrolyzer of the present invention; and a second elastic pad 100b that is an elastic pad for an alkaline water electrolyzer of the present invention.

[0142] In the electrolytic cell 3000, the cathode (first electrode) 30 is a porous plate (first porous plate) having flexibility. The cathode 30 can be fixed to the current collector 72 or the first elastic pad 100a. When the cathode 30 is fixed to the current collector 72 or the first elastic pad 100a, for example, a known method such as welding, pin fixing, and bolt fixing can be adopted without particular limitation. In addition, for example, the cathode 30 can also be fixed by folding the peripheral edge portion of the cathode 30 into the peripheral end portion of the collector 72. When fixing the cathode 30, it is preferable to fix the cathode 30 in a manner that does not impair the resilience of the elastic pad 100a.

[0143] In the electrolytic cell 3000, the anode (second electrode) 40 can be either a rigid porous plate or a flexible porous plate (second porous plate), but is preferably a rigid porous plate. When the anode 40 is a flexible porous plate, the anode 40 can be fixed to the collector 71 or to the second elastic pad 100b. In addition, when the anode 40 is a rigid porous plate, the anode 40 can be fixed to the second elastic pad 100b. When the anode 40 is fixed to the collector 71 or the second elastic pad 100b, for example, known methods such as welding, pin fixing, and bolt fixing can be used without particular restrictions. In addition, for example, the anode 40 can also be fixed by folding the peripheral edge of the anode 40 into the peripheral end of the collector 71. When fixing the anode 40, it is preferred to fix the anode 40 in a manner that does not damage the resilience of the elastic pad 100b.

[0144] In the electrolytic cell 3000, the cathode (first electrode) 30 is pressed toward the anode (second electrode) 40 by the first elastic pad 100a, and the anode (second electrode) 40 is pressed toward the cathode (second electrode) 30 by the second elastic pad 100b, thereby realizing a zero gap structure in which the diaphragm 1010 is clamped between the cathode (first electrode) 30 and the anode (second electrode) 40.

[0145] According to the electrolytic cell 3000 , since the diaphragm 1010 receives pressure from the elastic pads from both the anode side and the cathode side, deformation of the diaphragm 1010 near the electrode peripheral portion can be easily reduced.

[0146] In the electrolytic cell 3000, the cathode (first electrode) 30 is pressed toward the anode (second electrode) 40 by the elastic pad (first elastic pad) 100a of the present invention, and the anode (second electrode) 40 is pressed toward the cathode (first electrode) 30 by the elastic pad (second elastic pad) 100b of the present invention, so that the surface pressure of the anode 40 and the cathode 30 holding the diaphragm 1010 can be increased without damaging the uniformity of the surface pressure, and the proportion of the zero gap area in the electrode area can be increased. As a result, the operating voltage can be reduced and the energy efficiency can be improved.

[0147] In the electrolytic cell 3000, the surface pressure at which the cathode (first electrode) 30 is pressed toward the anode (second electrode) 40 and the surface pressure at which the anode (second electrode) 40 is pressed toward the cathode (first electrode) 30 are preferably 50 gf / cm 2 ~225gf / cm 2 , more preferably 75gf / cm 2 ~150gf / cm 2When the surface pressure is above the above lower limit, the operating voltage can be further reduced and the energy efficiency can be further improved. In addition, when the surface pressure is below the above upper limit, the repeated rebound resilience is further improved, and sufficient rebound force is maintained during long-term use, making it easy to maintain the energy efficiency of the alkaline water electrolyzer at a high level for a long time.

[0148] In the above description of the present invention, the alkaline water electrolyzers 1000, 2000 and 3000 in which the first electrode is a flexible porous plate and the second electrode is a rigid porous plate are cited as examples, but the present invention is not limited to this method. For example, the alkaline water electrolyzer can also be set to a method in which the first electrode is a flexible porous plate and the second electrode is also a flexible porous plate. Fig.15 FIG. 4 is a cross-sectional view schematically illustrating an alkaline water electrolysis cell 4000 (hereinafter also referred to as “electrolysis cell 4000”) according to another embodiment of the present invention. Fig.15 Sometimes, Figures 2 to 14 The element annotations shown in Figures 2 to 14 The same reference numerals as those in the figure are used, and their description is omitted. Fig.15As shown, the electrolytic cell 4000 comprises: an anode side frame 51, which includes a conductive back partition wall 51a and a flange portion 51b that is liquid-tightly combined with the entire peripheral portion of the back partition wall 51a, and defines an anode chamber A; a cathode side frame 52, which includes a conductive back partition wall 52a and a flange portion 52b that is liquid-tightly combined with the entire peripheral portion of the back partition wall 52a, and defines a cathode chamber C; an ion-permeable diaphragm 1010, which is arranged between the anode side frame 51 and the cathode side frame 52; a group of gaskets 21, 22, which are respectively arranged between the diaphragm 1010 and the flange portion 51b of the anode side frame 51 and between the diaphragm 1010 and the flange portion 52b of the cathode side frame 52, and sandwich the peripheral portion of the diaphragm 1010; conductive ribs 61, 61, ..., which extend from the anode side frame 51 is protrudingly provided with a back partition wall 51a of the cathode side frame 52; conductive ribs 62, 62, ..., which are protrudingly provided from the back partition wall 52a of the cathode side frame 52; a collector 72, which is held by the conductive ribs 62; a conductive elastic pad (first elastic pad) 100a, which is held by the collector 72; a cathode (first electrode) 30, which is arranged between the first elastic pad 100a and the diaphragm 1010; a collector 71, which is held by the conductive ribs 61; a conductive elastic pad (second elastic pad) 100b, which is held by the collector 71; an anode (second electrode) 2040, which is arranged between the second elastic pad 100b and the diaphragm 1010; and a rigid collector 91, which is connected to the anode 2040 and is arranged between the second elastic pad 100b and the anode (second electrode) 2040, and has conductivity. As such, the electrolytic cell 4000 comprises: an anode chamber A which accommodates the anode 2040 and generates oxygen; a cathode chamber C which accommodates the cathode 30 and generates hydrogen; an ion-permeable diaphragm 1010 which divides the anode chamber A from the cathode chamber C; a first elastic pad 100a which is an elastic pad for the alkaline water electrolyzer of the present invention; and a second elastic pad 100b which is an elastic pad for the alkaline water electrolyzer of the present invention.

[0149] In the electrolytic cell 4000, the cathode (first electrode) 30 is a porous plate (first porous plate) having flexibility. The cathode 30 can be fixed to the current collector 72 or the first elastic pad 100a. When the cathode 30 is fixed to the current collector 72 or the first elastic pad 100a, for example, a known method such as welding, pin fixing, and bolt fixing can be adopted without particular limitation. In addition, for example, the cathode 30 can also be fixed by folding the peripheral edge portion of the cathode 30 into the peripheral end portion of the current collector 72. When fixing the cathode 30, it is preferable to fix the cathode 30 in a manner that does not impair the resilience of the elastic pad 100a.

[0150] In the electrolytic cell 4000, the anode (second electrode) 2040 is a flexible porous plate (second porous plate) and is fixed to the rigid current collector 91. When the anode 2040 is fixed to the rigid current collector 91, for example, a known method such as welding, pin fixing, and bolt fixing can be adopted without particular limitation. In addition, for example, the anode 2040 can also be fixed by folding the peripheral edge portion of the anode 2040 into the peripheral end portion of the collector 71. When fixing the anode 2040, it is preferred to fix the anode 2040 in a manner that does not impair the resilience of the elastic pad 100b.

[0151] In the electrolytic cell 4000, the cathode (first electrode) 30 is pressed toward the anode (second electrode) 2040 by the first elastic pad 100a, and the anode (second electrode) 2040 is pressed toward the cathode (second electrode) 30 by the second elastic pad 100b via the rigid current collector 91, thereby realizing a zero gap structure in which the diaphragm 1010 is clamped between the cathode (first electrode) 30 and the anode (second electrode) 40.

[0152] In the electrolytic cell 4000, the rigid current collector 91 is arranged in a manner that the second electrode (anode) 2040 is sandwiched between the rigid current collector 91 and the diaphragm 1010, and the second electrode (anode) 2040 is supported by the rigid current collector 91. As the rigid current collector 91, a rigid current collector having conductivity can be used, for example, an expanded alloy, a stamped metal, etc. composed of a rigid conductive material having alkali resistance can be preferably used. Examples of the material of the rigid current collector 91 include single metals such as nickel and iron; stainless steels such as SUS304, SUS310, SUS310S, SUS316, and SUS316L; and metals obtained by plating the above materials with nickel. The rigid current collector 91 may be held by the second elastic pad 100b or not. When the rigid current collector 91 is held on the second elastic pad 100 b , a known method such as welding, pinning, or bolting can be used without particular limitation.

[0153] According to the electrolytic cell 4000, the second elastic pad 100b presses the second electrode 2040 via the rigid current collector 91 (i.e., the second electrode 2040 is supported from behind by the rigid current collector 91), so even if the second electrode 2040 is flexible, the pressure of the two electrodes pressing toward the diaphragm 1010 can be made more uniform over the entire surface of the two electrodes, so that the current density can be made more uniform. In addition, the diaphragm 1010 is subjected to pressure from the elastic body from both sides, the anode side and the cathode side, so that it is easy to reduce the deformation of the diaphragm 1010 near the electrode peripheral portion.

[0154] In the electrolytic cell 4000, the cathode (first electrode) 30 is pressed toward the anode (second electrode) 2040 by the elastic pad (first elastic pad) 100a of the present invention, and the anode (second electrode) 2040 is pressed toward the cathode (first electrode) 30 by the elastic pad (second elastic pad) 100b of the present invention through the rigid current collector 91, so that the surface pressure of the anode 2040 and the cathode 30 holding the diaphragm 1010 can be increased without damaging the uniformity of the surface pressure, and the proportion of the zero gap area in the electrode area can be increased. As a result, the operating voltage can be reduced and the energy efficiency can be improved.

[0155] In the electrolytic cell 4000, the surface pressure at which the cathode (first electrode) 30 is pressed toward the anode (second electrode) 2040 and the surface pressure at which the anode (second electrode) 2040 is pressed toward the cathode (first electrode) 30 are preferably 50 gf / cm 2 ~225gf / cm 2 , more preferably 75gf / cm 2 ~150gf / cm 2 When the surface pressure is above the above lower limit, the operating voltage can be further reduced and the energy efficiency can be further improved. In addition, when the surface pressure is below the above upper limit, the repeated rebound resilience is further improved, and sufficient rebound force is maintained during long-term use, making it easy to maintain the energy efficiency of the alkaline water electrolyzer at a high level for a long time.

[0156] In the above description of the present invention, an alkaline water electrolysis cell 4000 is cited as an example in which the current collector 71 supported by the conductive ribs 61 and the second elastic pad 100b supported by the current collector 71, and the rigid current collector 91 is supported by the second elastic pad 100b, but the present invention is not limited to this method. For example, in the electrolysis cell 4000, it is also possible to set the alkaline water electrolysis cell in a mode in which the second elastic pad 100b is not provided and the rigid current collector 91 is supported by the current collector 71. In addition, for example, in the electrolysis cell 4000, it is also possible to set the alkaline water electrolysis cell in a mode in which the second elastic pad 100b and the current collector 71 are not provided and the rigid current collector 91 is directly supported by the conductive ribs 61.

[0157] In the above description of the present invention, an alkaline water electrolysis cell 4000 is given as an example in which the second elastic pad 100b presses the anode 2040 toward the cathode 30 via the rigid current collector 91, but the present invention is not limited to this method. For example, an alkaline water electrolysis cell may be provided in which the second elastic pad presses the cathode toward the anode via the rigid current collector. Fig.16 FIG. 5 is a cross-sectional view schematically illustrating an alkaline water electrolysis cell 5000 (hereinafter, also referred to as “electrolysis cell 5000”) according to another embodiment of the present invention. Fig.16 Sometimes, Figures 2 to 15The element annotations shown in Figures 2 to 15 The same reference numerals as those in the figure are omitted for explanation. Fig.16 As shown, the electrolytic cell 5000 comprises: an anode side frame 51, which includes a conductive back partition wall 51a and a flange portion 51b that is liquid-tightly combined with the entire peripheral portion of the back partition wall 51a, and defines an anode chamber A; a cathode side frame 52, which includes a conductive back partition wall 52a and a flange portion 52b that is liquid-tightly combined with the entire peripheral portion of the back partition wall 52a, and defines a cathode chamber C; an ion-permeable diaphragm 1010, which is arranged between the anode side frame 51 and the cathode side frame 52; a group of gaskets 21, 22, which are respectively arranged between the diaphragm 1010 and the flange portion 51b of the anode side frame 51 and between the diaphragm 1010 and the flange portion 52b of the cathode side frame 52, and sandwich the peripheral portion of the diaphragm 1010; conductive ribs 61, 61, ..., which extend from the anode side The back partition wall 51a of the frame 51 is protrudingly arranged; the conductive ribs 62, 62, ..., which are protrudingly arranged from the back partition wall 52a of the cathode side frame 52; the collector 71, which is held by the conductive ribs 61; the elastic pad (first elastic pad) 100a with conductivity, which is held by the collector 71; the anode (first electrode) 2040, which is arranged between the first elastic pad 100a and the diaphragm 1010; the collector 72, which is held by the conductive ribs 62; the elastic pad (second elastic pad) 100b with conductivity, which is held by the collector 72; the cathode (second electrode) 30, which is arranged between the second elastic pad 100b and the diaphragm 1010; and the rigid collector 92, which is in contact with the cathode 30 and is arranged between the second elastic pad 100b and the cathode (second electrode) 30, and has conductivity. As such, the electrolytic cell 5000 comprises: an anode chamber A which accommodates the anode 2040 and generates oxygen; a cathode chamber C which accommodates the cathode 30 and generates hydrogen; an ion-permeable diaphragm 1010 which divides the anode chamber A from the cathode chamber C; a first elastic pad 100a which is an elastic pad for the alkaline water electrolyzer of the present invention; and a second elastic pad 100b which is an elastic pad for the alkaline water electrolyzer of the present invention.

[0158] In the electrolytic cell 5000, the anode (first electrode) 2040 is a porous plate (first porous plate) having flexibility. The anode 2040 can be fixed to the current collector 71 or the first elastic pad 100a. When the anode 2040 is fixed to the current collector 71 or the first elastic pad 100a, for example, a known method such as welding, pin fixing, and bolt fixing can be adopted without particular limitation. In addition, for example, the peripheral portion of the anode 2040 can also be fixed by folding the peripheral portion of the anode 2040 into the peripheral end portion of the current collector 71. When fixing the anode 2040, it is preferred to fix the anode 2040 in a manner that does not impair the resilience of the elastic pad 100a.

[0159] In the electrolytic cell 5000, the cathode (second electrode) 30 is a flexible porous plate (second porous plate) and is fixed to the rigid current collector 92. When the cathode 30 is fixed to the rigid current collector 92, for example, a known method such as welding, pin fixing, and bolt fixing can be adopted without particular limitation. In addition, for example, the cathode 30 can also be fixed by folding the peripheral edge of the cathode 30 into the peripheral end of the collector 72. When fixing the cathode 30, it is preferred to fix the cathode 30 in a manner that does not impair the resilience of the elastic pad 100b.

[0160] In the electrolytic cell 5000, the anode (first electrode) 2040 is pressed toward the cathode (second electrode) 30 by the first elastic pad 100a, and the cathode (second electrode) 30 is pressed toward the anode (first electrode) 2040 by the second elastic pad 100b via the rigid current collector 92, thereby realizing a zero gap structure in which the diaphragm 1010 is clamped between the anode (first electrode) 2040 and the cathode (second electrode) 30.

[0161] In the electrolytic cell 5000, the rigid current collector 92 is arranged in a manner that the second electrode (cathode) 30 is sandwiched between the rigid current collector 92 and the diaphragm 1010, and the second electrode (cathode) 30 is supported by the rigid current collector 92. As the rigid current collector 92, a rigid current collector having conductivity can be used, for example, an expanded alloy, a stamped metal, etc. composed of a rigid conductive material having alkali resistance can be preferably used. Examples of the material of the rigid current collector 92 include single metals such as nickel and iron; stainless steels such as SUS304, SUS310, SUS310S, SUS316, and SUS316L; and metals obtained by plating the above materials with nickel. The rigid current collector 92 may be retained by the second elastic pad 100b or may not be retained by the second elastic pad 100b. When the rigid current collector 92 is held on the second elastic pad 100 b , a known method such as welding, pinning, or bolting can be used without particular limitation.

[0162] According to the electrolytic cell 5000, the second elastic pad 100b presses the second electrode 30 via the rigid current collector 92 (i.e., the second electrode 30 is supported from behind by the rigid current collector 92), so even when the second electrode 30 is flexible, the pressure of the two electrodes pressing toward the diaphragm 1010 can be made more uniform over the entire surface of the two electrodes, so that the current density can be made more uniform. In addition, the diaphragm 1010 is subjected to pressure from the elastic body from both sides, the anode side and the cathode side, so that it is easy to reduce the deformation of the diaphragm 1010 near the electrode peripheral portion.

[0163] In the electrolytic cell 5000, the anode (first electrode) 2040 is pressed toward the cathode (second electrode) 30 by the elastic pad (first elastic pad) 100a of the present invention, and the cathode (second electrode) 30 is pressed toward the anode (first electrode) 2040 by the elastic pad (second elastic pad) 100b of the present invention through the rigid current collector 92, so that the surface pressure of the anode 2040 and the cathode 30 holding the diaphragm 1010 can be increased without damaging the uniformity of the surface pressure, and the proportion of the zero gap area in the electrode area can be increased. As a result, the operating voltage can be reduced and the energy efficiency can be improved.

[0164] In the electrolytic cell 5000, the surface pressure at which the anode (first electrode) 2040 is pressed toward the cathode (second electrode) 30 and the surface pressure at which the cathode (second electrode) 30 is pressed toward the anode (first electrode) 2040 through the rigid current collector 92 are preferably 50 gf / cm 2 ~225gf / cm 2 , more preferably 75gf / cm 2 ~150gf / cm 2 When the surface pressure is above the above lower limit, the operating voltage can be further reduced and the energy efficiency can be further improved. In addition, when the surface pressure is below the above upper limit, the repeated rebound resilience is further improved, and sufficient rebound force is maintained during long-term use, making it easy to maintain the energy efficiency of the alkaline water electrolyzer at a high level for a long time.

[0165] In the above description of the present invention, an alkaline water electrolysis cell 5000 is cited as an example in which the current collector 72 supported by the conductive ribs 62 and the second elastic pad 100b supported by the current collector 72 are provided, and the rigid current collector 92 is supported by the second elastic pad 100b, but the present invention is not limited to this method. For example, in the electrolysis cell 5000, it is also possible to set the alkaline water electrolysis cell in which the second elastic pad 100b is not provided and the rigid current collector 92 is supported by the current collector 72. In addition, for example, in the electrolysis cell 4000, it is also possible to set the alkaline water electrolysis cell in which the second elastic pad 100b and the current collector 72 are not provided and the rigid current collector 92 is directly supported by the conductive ribs 62.

[0166] In the above description of the present invention, the alkaline water electrolysis cell 1000-5000 is cited as an example in which the anode chamber has the conductive rib 61 and the cathode chamber has the conductive rib 62, but the present invention is not limited to this embodiment. For example, the alkaline water electrolysis cell may be configured in which one or both of the anode chamber and the cathode chamber do not have the conductive rib. Fig.17 FIG. 6 is a cross-sectional view schematically illustrating an alkaline water electrolysis cell 6000 (hereinafter also referred to as “electrolysis cell 6000”) according to another embodiment of the present invention. Fig.17 Sometimes, Figures 2 to 16 The element annotations shown in Figures 2 to 16 The same reference numerals as those in the figure are used, and their description is omitted. Fig.17 As shown, the electrolytic cell 6000 comprises: an anode side frame 51, which includes a conductive back partition wall 51a and a flange portion 51b that is liquid-tightly combined with the entire peripheral portion of the back partition wall 51a, and defines an anode chamber A; a cathode side frame 52, which includes a conductive back partition wall 52a and a flange portion 52b that is liquid-tightly combined with the entire peripheral portion of the back partition wall 52a, and defines a cathode chamber C; an ion-permeable diaphragm 1010, which is arranged between the anode side frame 51 and the cathode side frame 52; a group of gaskets 21, 22, which are respectively arranged between the diaphragm 1010 and the flange portion 51b of the anode side frame 51 and between the diaphragm 1010 and the cathode side frame 52 The cathode (first electrode) 30 is arranged in the cathode chamber C in a manner connected to the diaphragm 1010; the elastic pad (first elastic pad) 100a having conductivity is arranged between the back partition wall 52a of the cathode side frame 52 and the cathode 30 in a manner connected to the back partition wall 52a of the cathode side frame 52 and the cathode 30; the anode (second electrode) 40 is arranged in the anode chamber A in a manner connected to the diaphragm 1010; and the elastic pad (second elastic pad) 100b having conductivity is arranged between the back partition wall 51a of the anode side frame 51 and the anode 40 in a manner connected to the back partition wall 51a of the anode side frame 51 and the anode 40. As such, the electrolytic cell 6000 comprises: an anode chamber A which accommodates the anode 40 and generates oxygen; a cathode chamber C which accommodates the cathode 30 and generates hydrogen; an ion-permeable diaphragm 1010 which divides the anode chamber A from the cathode chamber C; a first elastic pad 100a which is an elastic pad for the alkaline water electrolyzer of the present invention; and a second elastic pad 100b which is an elastic pad for the alkaline water electrolyzer of the present invention.

[0167] In the electrolytic cell 6000, the cathode (first electrode) 30 is a porous plate (first porous plate) having flexibility. The cathode 30 can be fixed to the back partition wall 52a or the first elastic pad 100a. When the cathode 30 is fixed to the back partition wall 52a or the first elastic pad 100a, for example, a known method such as welding, pin fixing, and bolt fixing can be adopted without particular limitation. In addition, for example, a hook (lock-shaped member) can be provided on the inner surface of the back partition wall 52a, and the cathode 30 can be fixed to the back partition wall 52a by hooking the cathode 30 on the hook. When fixing the cathode 30, it is preferable to fix the cathode 30 in a manner that does not damage the resilience of the elastic pad 100a.

[0168] In the electrolytic cell 6000, the anode (second electrode) 40 may be a rigid porous plate or a flexible porous plate (second porous plate), but is preferably a rigid porous plate. When the anode 40 is a flexible porous plate, the anode 40 may be fixed to the back partition wall 51a or the second elastic pad 100b. In addition, when the anode 40 is a rigid porous plate, the anode 40 may be fixed to the second elastic pad 100b. When the anode 40 is fixed to the back partition wall 51a or the second elastic pad 100b, for example, known methods such as welding, pin fixing, and bolt fixing can be adopted without particular limitation. In addition, for example, a hook (lock-shaped member) may be provided on the inner surface of the back partition wall 51a, and the anode 40 may be fixed to the back partition wall 51a by hooking the anode 40 on the hook. When fixing the anode 40, it is preferred to fix the anode 40 in a manner that does not damage the resilience of the elastic pad 100b.

[0169] In the electrolytic cell 6000, the cathode (first electrode) 30 is pressed toward the anode (second electrode) 40 by the first elastic pad 100a, and the anode (second electrode) 40 is pressed toward the cathode (second electrode) 30 by the second elastic pad 100b, thereby realizing a zero gap structure in which the diaphragm 1010 is clamped between the cathode (first electrode) 30 and the anode (second electrode) 40.

[0170] By using the alkaline water electrolyzer 6000 in such a manner, the same effect as the electrolyzer 3000 described above can be obtained. That is, according to the electrolyzer 6000, the diaphragm 1010 is subjected to the pressure of the elastic pad from both sides of the anode side and the cathode side, so it is easy to reduce the deformation of the diaphragm 1010 near the electrode peripheral portion. Moreover, in the electrolyzer 6000, the anode chamber A and the cathode chamber C do not have conductive ribs, so the thickness of each electrolysis unit can be thinned, so the electrolyzer can be miniaturized and the gas production per unit occupied land area can be increased. In addition, one or both of the anode chamber and the cathode chamber do not have conductive ribs, so the materials constituting the electrolyzer and the man-hours required for the production of the electrolyzer can be reduced.

[0171] In the electrolytic cell 6000, the cathode (first electrode) 30 is pressed toward the anode (second electrode) 40 by the elastic pad (first elastic pad) 100a of the present invention, and the anode (second electrode) 40 is pressed toward the cathode (first electrode) 30 by the elastic pad (second elastic pad) 100b of the present invention, so that the surface pressure of the anode 40 and the cathode 30 holding the diaphragm 1010 can be increased without damaging the uniformity of the surface pressure, and the proportion of the zero gap area in the electrode area can be increased. As a result, the operating voltage can be reduced and the energy efficiency can be improved.

[0172] In the electrolytic cell 6000, the surface pressure at which the cathode (first electrode) 30 is pressed toward the anode (second electrode) 40 and the surface pressure at which the anode (second electrode) 40 is pressed toward the cathode (first electrode) 30 are preferably 50 gf / cm 2 ~225gf / cm 2 , more preferably 75gf / cm 2 ~150gf / cm 2 When the surface pressure is above the above lower limit, the operating voltage can be further reduced and the energy efficiency can be further improved. In addition, when the surface pressure is below the above upper limit, the repeated rebound resilience is further improved, and sufficient rebound force is maintained during long-term use, making it easy to maintain the energy efficiency of the alkaline water electrolyzer at a high level for a long time.

[0173] In the above description of the present invention, an elastic pad 100 ( Figure 2 ) as an alkaline water electrolyzer 1000, 2000, 3000, 4000, 5000, 6000 having a conductive elastic pad (100, 100a, 100b), but the present invention is not limited to this embodiment. For example, the alkaline water electrolyzer having a conductive elastic pad 200, 300, 400, 500, or 600 of the present invention can also be provided as an alkaline water electrolyzer having a conductive elastic pad.

[0174] <3. Gas Production Method>

[0175] The gas production method of the third embodiment of the present invention is a method for producing hydrogen and oxygen by electrolyzing alkaline water, including (a) a step of electrolyzing alkaline water using the alkaline water electrolyzer of the present invention (hereinafter also referred to as "step (a)"). As the alkaline water electrolyzer in step (a), an alkaline water electrolyzer of any of the above-described embodiments can be used. As alkaline water, a known alkaline aqueous solution (e.g., a KOH aqueous solution, a NaOH aqueous solution, etc.) used in the production of hydrogen and oxygen by alkaline water electrolysis can be used without particular limitation.

[0176] Step (a) can be carried out by supplying a polar liquid (alkaline water) to each anode chamber and each cathode chamber of the alkaline water electrolyzer of the present invention, so as to apply a voltage in a manner that a predetermined electrolysis current flows between the anode and cathode. The gas generated by electrolysis is recovered from each polar chamber together with the polar liquid, and gas-liquid separation is performed, so that hydrogen can be recovered from the cathode chamber and oxygen can be recovered from the anode chamber respectively. The polar liquid separated from the gas by gas-liquid separation can be supplied to each polar chamber again while replenishing water as needed.

[0177] According to the gas production method of the present invention, alkaline water is electrolyzed using the alkaline water electrolysis cell of the present invention, so that the energy efficiency of gas production by alkaline water electrolysis can be improved.

[0178] Description of Reference Numerals

[0179] 10, 210, 310, metal mesh; 100, 200, 300, 400, 500, 600, elastic pad for alkaline water electrolyzer; 1010, diaphragm (with ion permeability); 21, 22, gasket; 30, 2030, cathode; 40, 2040, anode; 51, anode side frame; 52, cathode side frame; 51a, 52a, back partition wall (with conductivity); 51b, 52b, flange; 61, 62, conductive rib; 71, 72, collector; 100a, first elastic pad; 100b , the second elastic pad; 91, 92, rigid collector; 900, conventional zero-gap type electrolytic cell; 910, pole chamber unit; 911, conductive partition wall; 912, flange; 913, 914, conductive ribs; 920, ion-permeable diaphragm; 930, gasket; 940, anode; 950, collector; 960, conductive elastic pad; 970, cathode; 1000, 2000, 3000, 4000, 5000, 6000, alkaline water electrolytic cell; A, anode chamber; C, cathode chamber.

Claims

1. An elastic pad for an alkaline water electrolyzer, wherein: The elastic pad for alkaline water electrolysis cell comprises at least one metal mesh woven or braided with metal wires and having spring elasticity in the thickness direction. The metal wire is a single wire with a wire diameter of 0.16 mm to 0.29 mm or a wire bundle formed by bundling a plurality of single wires with a wire diameter of 0.08 mm to 0.15 mm, or a combination thereof. When the elastic pad for alkaline water electrolyzer is compressed and deformed by 50% twice, the rebound force per unit area at the second compression deformation of 50% is 40 gf / cm 2 above.

2. The elastic pad for alkaline water electrolyzer according to claim 1, wherein: The elastic pad for alkaline water electrolysis tank has a rebound force per unit area of ​​100 gf / cm when it is compressed and deformed by 50%. 2 ~450gf / cm 2 .

3. The elastic pad for alkaline water electrolyzer according to claim 1 or 2, wherein: The metal mesh is formed into a wave shape having an amplitude in a thickness direction of the metal mesh.

4. The elastic pad for alkaline water electrolyzer according to claim 3, wherein: The plurality of metal meshes overlap in the thickness direction. The metal meshes in each group of two adjacent metal meshes overlap so that the ridges of the wave shape formed in one metal mesh of the group intersect with the ridges of the wave shape formed in the other metal mesh of the group when the elastic pad is viewed from above.

5. The elastic pad for alkaline water electrolyzer according to claim 1 or 2, wherein: The total thickness of the elastic pad for the alkaline water electrolyzer is 7.5 mm to 10 mm.

6. An alkaline water electrolyzer, wherein: The alkaline water electrolyzer has: an anode chamber that receives the anode and produces oxygen; a cathode chamber that receives the cathode and produces hydrogen; an ion-permeable membrane that separates the anode chamber from the cathode chamber; as well as A first elastic pad is the elastic pad for an alkaline water electrolyzer according to any one of claims 1 to 5, The first electrode as the cathode is a flexible porous plate and is pressed toward the second electrode as the anode by the first elastic pad.

7. An alkaline water electrolyzer, wherein: The alkaline water electrolyzer has: an anode chamber that receives the anode and produces oxygen; a cathode chamber that receives the cathode and produces hydrogen; an ion-permeable membrane that separates the anode chamber from the cathode chamber; as well as A first elastic pad is the elastic pad for an alkaline water electrolyzer according to any one of claims 1 to 5, The first electrode as the anode is a flexible porous plate and is pressed toward the second electrode as the cathode by the first elastic pad.

8. The alkaline water electrolyzer according to claim 6 or 7, wherein: The second electrode is a rigid porous plate.

9. The alkaline water electrolyzer according to claim 8, wherein: The alkaline water electrolyzer further comprises a second elastic pad, and the second elastic pad is the elastic pad for the alkaline water electrolyzer according to any one of claims 1 to 5. The second electrode is pressed toward the first electrode by the second elastic pad.

10. The alkaline water electrolyzer according to claim 6 or 7, wherein: The alkaline water electrolyzer further comprises a second elastic pad, and the second elastic pad is the elastic pad for the alkaline water electrolyzer according to any one of claims 1 to 5. The second electrode is a flexible second porous plate. The second electrode is pressed toward the first electrode by the second elastic pad.

11. The alkaline water electrolyzer according to claim 6 or 7, wherein: The alkaline water electrolyzer further comprises a conductive rigid current collector disposed in contact with the second electrode. The second electrode is a flexible second porous plate. The second electrode is supported by the rigid current collector.

12. The alkaline water electrolyzer according to claim 11, wherein: The alkaline water electrolyzer further comprises a second elastic pad, and the second elastic pad is the elastic pad for the alkaline water electrolyzer according to any one of claims 1 to 5. The second electrode is pressed toward the first electrode by the second elastic pad via the rigid current collector.

13. A method for producing gas, which is a method for producing hydrogen and oxygen by electrolyzing alkaline water, wherein: The gas production method comprises: (a) A step of electrolyzing alkaline water using the alkaline water electrolysis cell according to any one of claims 6 to 12.

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