KR20240063863A - electrolyzer - Google Patents

Abstract

a first frame having a first conductive partition wall and a first flange portion having a first gasket contact surface, and defining an anode chamber; a second frame body having a conductive second barrier rib and a second flange portion and defining a cathode chamber; a diaphragm disposed between the first frame and the second frame and dividing the anode chamber and the cathode chamber; a gasket sandwiched between the first flange portion and the second flange portion and maintaining the diaphragm; an anode disposed in the anode chamber; It has a cathode disposed in a cathode chamber, the gasket has first and second gasket elements, and the first frame has a first nickel plating layer with a thickness of 27 μm or more exposed to the first gasket contact surface, An alkaline water electrolyzer wherein the surface roughness of the first gasket contact surface is 10㎛ or less as an arithmetic average roughness Ra.

Description

electrolyzer

The present invention relates to an electrolyzer for alkaline water electrolysis.

As a method for producing hydrogen gas and oxygen gas, the alkaline water electrolysis method is known. In the alkaline water electrolysis method, a basic aqueous solution (alkaline water) in which an alkali metal hydroxide (e.g., NaOH, KOH, etc.) is dissolved is used as an electrolyte to electrolyze water, thereby generating hydrogen gas from the cathode and oxygen gas from the anode. occurs. As an electrolytic cell for alkaline water electrolysis, an electrolytic cell is known that has an anode chamber and a cathode chamber partitioned by an ion-permeable diaphragm, with an anode disposed in the anode chamber and a cathode disposed in the cathode chamber. The liquid nature of each polar liquid in the anode chamber and cathode chamber of the alkaline water electrolyzer is in the strongly alkaline range.

Japanese Patent Laid-Open No. 2019-99845 International Publication No. 2019/111832 International Publication No. 2019/188260 International Publication No. 2019/188261 International Publication No. 2021/085334 International Publication No. 2013/191140 Japanese Patent Laid-Open No. 2016-094650 Japanese Patent Laid-Open Publication No. 57-137486 Japanese Patent Laid-open Publication No. 1-119687 Japanese Patent No. 6404685 Publication Japanese Patent No. 6621970 Publication International Publication No. 2015/064644

Manabu Noguchi, Hiroshi Yakuwa, “Corrosion Method Lecture - High Temperature Corrosion Basics and Countermeasure Techniques -” 1st Edition: High Temperature Corrosion Basics I (Basic Theory). Evara Cibo, no. 252(2016-10), 32-39.

The present inventor has described an electrolytic cell that can be suitably used for the electrolysis of alkaline water, especially for the electrolysis of alkaline water under pressurized conditions. Consists of a second electrolytic element having a second flange portion on the outer periphery, a gasket having electrical insulation sandwiched between the first flange portion and the second flange portion, and the first pole chamber and the second flange portion. It includes a diaphragm that isolates two polar chambers, wherein the first flange portion has a first cross section facing the second flange portion and in contact with the gasket, and the second flange portion has a first cross section of the first flange portion. It has a second end face that faces the first end face and is in contact with the gasket, wherein the gasket is sandwiched between the first end face and the second end face, and the first flange portion is attached to the outer periphery of the gasket. A gasket holding portion is provided in contact with the outer peripheral side, and the gasket holding portion protrudes and extends beyond the first end surface toward the second electrolytic element in a stacking direction of the first electrolytic element and the second electrolytic element. , the second flange portion has a recessed portion that recedes from the second end surface toward the opposite side from the first electrolytic element in the stacking direction at the outer peripheral portion of the second flange portion, and the recessed portion is the gasket. An “electrolyzer configured to accommodate at least part of the holding portion” has been invented and an application has been filed (Patent Document 1). Patent Document 1 describes using a rigid material with alkali resistance, such as iron, nickel, or stainless steel, as the material for each flange portion.

As a material for the conductive partition and flange portion constituting each pole chamber, nickel is considered most preferable from the viewpoint of alkali resistance and conductivity. However, the use of nickel members increases the cost of the electrolytic cell. From the viewpoint of reducing the cost of the electrolytic cell, it is desirable to use inexpensive metal materials such as carbon steel (eg, mild steel, etc.) for the structural members of the electrolytic cell. However, upon further examination by the present inventor, it was found that in an alkaline water electrolyzer employing an inexpensive metal material such as carbon steel for the flange portion, the sealing properties of the electrolyte solution and gas are likely to deteriorate, especially between the flange portion on the anode chamber side and the gasket. It has been done. It was difficult to solve this problem simply by providing a nickel plating layer on the surface of the flange portion.

The object of the present invention is to provide an alkaline water electrolyzer capable of suppressing the deterioration of the sealing properties of the anolyte and the anode chamber gas.

The present invention includes the following aspects [1] to [14].

[1] A first frame body having a conductive first partition and a first flange portion provided on the outer periphery of the first partition, and defining an anode chamber;

A second frame body having a conductive second barrier rib and a second flange portion provided on the outer periphery of the second barrier rib, and defining a cathode chamber;

an ion-permeable diaphragm disposed between the first frame and the second frame and dividing the anode chamber and the cathode chamber;

a gasket sandwiched between a first flange portion of the first frame and a second flange portion of the second frame and maintaining the diaphragm;

an anode disposed in the anode chamber and electrically connected to the first partition,

A cathode disposed in the cathode chamber and electrically connected to the second partition wall.

Equipped with

The gasket is,

a first gasket element contacting the first flange portion and the diaphragm;

A second gasket element contacting the second flange portion and the diaphragm.

Equipped with

The first flange portion has a first gasket contact surface that contacts the first gasket element,

The first frame body has a first nickel plating layer with a thickness of 27 μm or more exposed to the first gasket contact surface of the first flange portion,

An alkaline water electrolyzer wherein the surface roughness of the first gasket contact surface is 10 μm or less as an arithmetic average roughness Ra.

[2] The alkaline water electrolyzer according to [1], wherein the surface roughness of the first gasket contact surface is 40 μm or less as a maximum height Rz.

[3] The alkaline water electrolyzer according to [1] or [2], wherein the first nickel plating layer is an electroless nickel plating layer.

[4] The first frame body,

At least one steel first core,

The first nickel plating layer provided on the surface of the first core material

The alkaline water electrolyzer according to any one of [1] to [3], including.

[5] The alkaline water according to any one of [1] to [4], wherein the first nickel plating layer is continuously provided on the first gasket contact surface and the surface facing the anode chamber of the first frame. Electrolyzer.

[6] The alkaline water electrolyzer according to any one of [1] to [5], wherein the first nickel plating layer has a thickness of 30 to 100 μm.

[7] The first frame is,

A conductive support member provided to protrude from the first partition into the anode chamber and supports the anode.

The alkaline water electrolyzer according to any one of [1] to [6], further comprising:

[8] The second flange portion has a second gasket contact surface that contacts the second gasket element,

The second frame body has a second nickel plating layer with a thickness of 27 μm or more exposed to the second gasket contact surface of the second flange portion,

The alkaline water electrolyzer according to any one of [1] to [7], wherein the surface roughness of the second gasket contact surface is 10 μm or less as an arithmetic average roughness Ra.

[9] The alkaline water electrolyzer according to [8], wherein the surface roughness of the second gasket contact surface is 40 μm or less in terms of maximum height Rz.

[10] The alkaline water electrolyzer according to [8] or [9], wherein the second nickel plating layer is an electroless nickel plating layer.

[11] The second frame body,

at least one second heartwood of the force,

The second nickel plating layer provided on the surface of the second core material

The alkaline water electrolyzer according to any one of [8] to [10], including.

[12] The alkaline water according to any one of [8] to [11], wherein the second nickel plating layer is continuously provided on the second gasket contact surface and the surface facing the cathode chamber of the second frame. Electrolyzer.

[13] The alkaline water electrolyzer according to any one of [8] to [12], wherein the second nickel plating layer has a thickness of 50 to 100 μm.

[14] The second frame is,

A conductive support member provided to protrude from the second partition into the cathode chamber and supports the cathode.

The alkaline water electrolyzer according to any one of [1] to [13], further comprising:

According to the alkaline water electrolyzer of the present invention, the first frame defining the anode chamber is provided with a nickel plating layer of 27 μm or more in thickness exposed to the gasket contact surface of the flange portion, and the surface roughness of the gasket contact surface is 10 as the arithmetic average roughness Ra. By being less than ㎛, it is possible to suppress a decrease in the sealing properties of the anolyte and the anode chamber gas.

[Figure 1] is a cross-sectional view schematically explaining the electrolytic cell 100 according to an embodiment of the present invention.
[FIG. 2] A diagram showing the first frame 10 taken out from FIG. 1.
[FIG. 3] A diagram showing the second frame 20 taken out from FIG. 1.
[Figure 4] is a cross-sectional view schematically explaining the electrolytic cell 200 according to another embodiment of the present invention.
[FIG. 5] A diagram showing the third frame 210 taken out from FIG. 4.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention will be described with reference to the drawings. However, the present invention is not limited to these forms. Additionally, the drawings do not necessarily reflect exact dimensions. Additionally, in the drawings, some symbols may be omitted. In this specification, unless otherwise specified, the notation "A to B" for numerical values A and B shall mean "A or more and B or less." In this notation, if a unit is added only to numerical value B, the unit is assumed to apply to numerical value A as well. Additionally, the words “or” and “or” shall mean logical sum, unless otherwise specified. In addition, for elements E ₁ and E ₂ , the notation “E ₁ and/or E ₂ ” means “E ₁ or E ₂ , or a combination thereof”, and elements E ₁ ,... , E _N (N is an integer of 3 or more), 「E ₁ , … , E _N-1 , and/or E _N ” means “E ₁ , … , E _N-1 , or E _N , or a combination thereof.”

Figure 1 is a cross-sectional view schematically explaining an electrolytic cell 100 according to an embodiment of the present invention. The electrolytic cell 100 is an electrolytic cell for electrolyzing alkaline water. As shown in FIG. 1, the electrolytic cell 100 includes a first frame 10 defining an anode chamber A; a second frame body (20) defining the cathode chamber (C); an ion-permeable diaphragm 40 disposed between the first frame 10 and the second frame 20 and dividing the anode chamber A and the cathode chamber C; an electrically insulating gasket (30) clamped between the first frame (10) and the second frame (20) and maintaining the periphery of the diaphragm (40); An anode 50 disposed in the anode chamber A and electrically connected to the first partition 11, and a cathode disposed in the cathode chamber C and electrically connected to the second partition 21 ( 60) is provided. The first frame 10 has a conductive first partition 11 and a first flange portion 12 provided on the outer periphery of the partition 11. The second frame 20 also has a conductive second partition wall 21 and a second flange portion 22 provided on the outer periphery of the partition wall 21. The partition walls 11 and 21 partition adjacent electrolytic cells and electrically connect the adjacent electrolytic cells in series. The gasket 30 includes a first gasket element 31 that contacts the first flange portion 12 and the diaphragm 40, and a second gasket element that contacts the second flange portion 22 and the diaphragm 40. It has an element 32. The first flange portion 12 defines the anode chamber A together with the partition wall 11, the partition wall 40, and the gasket element 31, and the second flange part 22 defines the partition wall 21, Together with the diaphragm 40 and gasket element 32, it defines the cathode chamber C.

The first frame 10 also includes at least one conductive support member (first support member) 13, 13, . . . provided to protrude from the partition 11. (hereinafter sometimes referred to as “support member 13”), and the anode 50 is held by the support member 13. The support member 13 is electrically connected to the first partition 11 and the anode 50. The second frame 20 also includes conductive support members (second support members) 23, 23, . . . provided to protrude from the partition 21. (hereinafter sometimes referred to as “support member 23”), and the cathode 60 is held by the support member 23. The support member 23 is electrically connected to the second partition 21 and the cathode 60. In addition, although not shown in FIG. 1, the first flange portion 12 has an anolyte supply passage for supplying the anolyte to the anode chamber A, and a means for recovering the anolyte and the gas generated from the anode from the anolyte A. It is equipped with an anolyte recovery channel. In addition, the second flange portion 22 is provided with a catholyte supply passage for supplying catholyte to the cathode chamber (C) and a catholyte recovery passage for recovering the catholyte and the gas generated from the cathode from the cathode chamber (C). there is.

As the material of the first partition 11 and the second partition 21, a rigid conductive material with alkali resistance can be used, and examples include simple metals such as nickel and iron; Metal materials such as ordinary steel (i.e., low-carbon steel and medium-carbon steel), carbon steel such as high carbon steel, and steel such as stainless steel (e.g., SUS304, SUS310, SUS310S, SUS316, SUS316L, etc.) can be preferably used. From the viewpoint of cost reduction and strength, steel materials such as carbon steel and stainless steel can be particularly preferably employed.

As the material of the first flange portion 12, a rigid material with alkali resistance can be used, and examples include simple metals such as nickel and iron; Metal materials such as ordinary steel (i.e., low carbon steel and medium carbon steel), carbon steel such as high carbon steel, and stainless steel (e.g., SUS304, SUS310, SUS310S, SUS316, SUS316L, etc.) can be preferably used. . In addition to the viewpoints of cost reduction and strength, the problem of deterioration of the sealing properties of electrolyte and gas tends to occur among the gaskets described above, and the effect of the present invention for preventing this is likely to be more significantly exhibited, so carbon steel and stainless steel Steel materials such as these can be particularly preferably employed, and carbon steel is most suitable.

As the material of the second flange portion 22, a rigid material with alkali resistance can be used, and examples include simple metals such as nickel and iron; In addition to metal materials such as ordinary steel (i.e. low carbon steel and medium carbon steel), carbon steel such as high carbon steel, stainless steel (e.g. SUS304, SUS310, SUS310S, SUS316, SUS316L, etc.), non-metals such as reinforced plastic Materials can also be used, and from the viewpoint of cost reduction and strength, steel materials such as carbon steel and stainless steel can be particularly preferably employed.

The partition wall 11 and the flange portion 12 of the first frame 10 may be joined by welding, adhesion, etc., or may be formed integrally with the same material. Similarly, the partition wall 21 and the flange portion 22 of the second frame 20 may be joined by welding or adhesiveness, or may be formed integrally with the same material. However, because it is easy to increase resistance to pressure inside the pole chamber, it is preferable that the partition wall 11 and the flange portion 12 of the first frame 10 are integrally formed of the same material, and the second frame body 10 is made of the same material. It is preferable that the partition wall 21 and the flange portion 22 of the frame 20 are formed integrally with the same material.

As the first support member 13 and the second support member 23, a support member that can be used as a conductive rib in an alkaline water electrolyzer can be used. In the electrolytic cell 100, the first support member 13 is installed upright from the partition 11 of the first frame 10, and the second support member 23 is connected to the second frame 20. ) is erected from the partition wall 21. As long as the first support members 13 can fix and maintain the anode 50 with respect to the first frame 10, the connection method, shape, number, and arrangement of the first support members 13 are particularly Not limited. In addition, as long as the second support member 23 can fix and maintain the cathode 60 with respect to the second frame 20, the connection method, shape, number, and arrangement of the second support member 23 There is no particular limitation.

As the material of the first support member 13 and the second support member 23, a rigid conductive material with alkali resistance can be used, and examples include simple metals such as nickel and iron; Metal materials such as ordinary steel (i.e., low carbon steel and medium carbon steel), carbon steel such as high carbon steel, and stainless steel (e.g., SUS304, SUS310, SUS310S, SUS316, SUS316L, etc.) can be preferably used. From the viewpoint of cost reduction and strength, steel materials such as carbon steel and stainless steel can be particularly preferably employed.

In measuring the anode chamber of an alkaline water electrolyzer, simply providing a nickel plating layer on the gasket contact surface of the flange portion can prevent the deterioration of the sealing properties of the anolyte solution and anode chamber gas due to nickel corrosion on the gasket contact surface of the flange portion. The present inventor considers the reason for this as follows. The polarity of each polar liquid in the anode chamber and cathode chamber of the alkaline water electrolyzer is in the strongly alkaline range. Such alkaline water uses the reduction reaction of dissolved oxygen gas (O ₂ ) as a cathode (anode of a local battery) reaction, and is corrosive to base metals such as iron. The gasket contact surface of the flange part usually appears sufficiently smooth when viewed visually, but microscopically, irregularities remain, and when the flange part is fastened together with the gasket, alkaline water intrudes between the concave part of the gasket contact surface and the gasket. It is thought that a fine tunnel-shaped flow path is formed that allows for this. If alkaline water enters between the gasket contact surface of the metal flange portion and the gasket, it may corrode (ionize) the metal on the gasket contact surface. It is thought that microscopic pockets are created in areas where metal corrosion has occurred, and more alkaline water flows into these pockets through the existing microtunnel-shaped flow path, expanding the metal corrosion, thereby creating a vicious cycle in which the microtunnel-shaped channel expands and/or progresses. . If the flow path on this tunnel is sufficiently developed, it is possible for alkaline water and, in severe cases, gas to penetrate into the outer periphery of the gasket contact surface of the flange portion, and it is thought that the sealing properties of the electrolyte solution and gas deteriorate.

Nickel has sufficient corrosion resistance to alkaline water. Therefore, even if the flange portion is formed of a base metal such as iron (e.g., carbon steel, etc.), if nickel plating is applied to the gasket contact surface of the flange portion, for example, fine irregularities may appear on the gasket contact surface of the flange portion. Even if it remains and a fine tunnel is formed between the gaskets, expansion of metal corrosion caused by alkaline water can be avoided, so it is thought that the sealing properties of the electrolyte solution and gas are maintained. For that purpose, the thickness of the nickel plating layer is sufficient to be 2 to 10 μm, and it is simply not economical to provide a thicker nickel plating layer than this. However, in the anode chamber of an alkaline water electrolyzer, it may be a problem that the metal flange portion is placed at an oxidative potential and that a large amount of oxygen gas is generated.

In particular, the gas generated in the cathode chamber of the alkaline water electrolyzer is hydrogen gas, so the cathode chamber is filled with a reducing atmosphere, while the gas generated in the anode chamber is oxygen gas, so the anode chamber is filled with an oxidizing atmosphere, and the anolyte Oxygen gas dissolves to saturation level. In the vicinity of the oxygen evolution reaction potential, the oxidation reaction of nickel metal proceeds thermodynamically (Equation (1) or (2) below). Nickel (II) hydroxide is stable in an aqueous alkaline solution under non-oxidizing conditions, but oxidation of nickel may proceed further depending on conditions such as potential and oxygen gas activity (e.g., formulas (3) to (6) below).

Ni+2OH ^- →Ni(OH) ₂ +2e ^- … (One)

Ni+(1/2)O ₂ +H ₂ O→Ni(OH) ₂ … (2)

Ni(OH) ₂ +OH ^- →NiOOH+H ₂ O+e ^- … (3)

2Ni(OH) ₂ +(1/2)O ₂ →2NiOOH+H ₂ O... (4)

NiOOH+OH ^- →NiO ₂ +H ₂ O+e ^- … (5)

2NiOOH+(1/2)O ₂ →2NiO ₂ +H ₂ O … (6)

This oxidation reaction of nickel mainly proceeds on and near the surface of nickel. Generally, at the oxide film/atmospheric gas interface, if the gas flow is sufficient, the dissociation pressure of oxygen from the oxide becomes equal to the partial pressure of oxygen in the atmosphere. If the partial pressure of oxygen in the atmosphere is higher than the dissociation pressure, the metal is oxidized, and if it is lower than the dissociation pressure, the oxide is reduced. A gradient of oxygen partial pressure occurs in the oxide film, and the deeper the oxide film, the lower the partial pressure. Assuming that thermodynamic equilibrium is established at the metal/oxide interface, the system can be considered to be in an equilibrium state where the metal and oxide coexist, so the oxygen partial pressure becomes equal to the dissociation pressure. Therefore, it is thought that the higher the activity of oxygen gas in the phase in contact with the oxide film, the more the metal/oxide balance is tilted toward the oxide side, and the thicker the oxide film becomes. Since these nickel oxidation reactions are reversible reactions, when the operation of the alkaline water electrolyzer is stopped, the reverse reaction (reduction reaction) of the nickel oxidation reaction can proceed. It is believed that the decrease in oxygen gas activity in the anode chamber due to recovery of oxygen gas from the anode chamber also supports the reverse reaction. Nickel oxidation reactions and reverse reactions on and near the nickel surface may result in local stress changes on and near the nickel surface through changes in crystal structure. Repetition of the oxidation reaction of nickel and the reverse reaction on the nickel surface and its vicinity may accelerate deterioration of the nickel plating film through repetition of local stress changes. This problem can become particularly noticeable under conditions where the operation and stop of the alkaline water electrolyzer are frequently repeated. An example of such an operating condition is a case where an unstable power source such as renewable energy (e.g. solar power generation, wind power generation, tidal power generation, etc.) is used as the current source of the alkaline water electrolyzer without being stabilized by a secondary battery, etc. I can hear it. When the nickel plating film deteriorates, surface irregularities also develop, which is thought to ultimately reduce the sealing performance of the electrolyte and gas between the flange portion and the gasket.

The present inventor provided a nickel plating layer with a thickness of 27 ㎛ or more to expose the gasket contact surface of the flange portion on the anode actual side, and set the surface roughness of the gasket contact surface to 10 ㎛ or less in terms of arithmetic mean roughness Ra, thereby making the anode of an alkaline water electrolyzer. It was found that the deterioration of the sealing properties of the electrolyte solution and gas could be suppressed even under strict conditions regarding metal corrosion, which are said to be actual measurements.

FIG. 2 is a view in which only the first frame 10 is taken out from FIG. 1. In FIG. 2, elements already shown in FIG. 1 are given the same symbols as those in FIG. 1, and descriptions may be omitted. The first flange portion 12 has a first gasket contact surface 12e, which contacts the first gasket element 31 (see FIG. 1). The first frame 10 is provided with a first nickel plating layer 14 exposed to the first gasket contact surface 12e of the first flange portion 12. The thickness of the first nickel plating layer 14 at the first gasket contact surface 12e is determined from the viewpoint of suppressing the deterioration of the sealing properties of the anolyte and the anode chamber gas, and corrosion resistance in alkaline water with high oxygen gas activity. From the viewpoint of the height over a long period of time, it is 27 μm or more, and more preferably 30 μm or more. The upper limit of the thickness is not particularly limited, but may be, for example, 100 μm or less from the viewpoint of manufacturing cost.

From the viewpoint of suppressing the deterioration of the sealing properties of the anolyte and the anode chamber gas, and from the viewpoint of increasing corrosion resistance in alkaline water with high oxygen gas activity over a long period of time, the surface roughness of the first gasket contact surface 12e is determined in accordance with JIS B0601. The prescribed arithmetic mean roughness Ra is 10 μm or less, preferably 9 μm or less, or 8 μm or less. The lower limit of the arithmetic mean roughness Ra is not particularly limited, but may be 1 μm or more, or 2 μm or more in one embodiment, from the viewpoint of stability of fixation of the gasket and manufacturing cost. In one embodiment, the arithmetic mean roughness Ra may be 1 to 10 μm, or 1 to 9 μm, or 1 to 8 μm.

From the viewpoint of further suppressing the deterioration of the sealing properties of the anolyte and the anode chamber gas, and further improving the corrosion resistance in alkaline water with high oxygen gas activity, the surface roughness of the first gasket contact surface 12e is specified in JIS B0601. The maximum height Rz is preferably 40 μm or less, more preferably 35 μm or less. The lower limit of the maximum height Rz is not particularly limited, but from the viewpoint of manufacturing cost, in one embodiment, it may be 2 μm or more, or 4 μm or more, or 6 μm or more, or 8 μm or more. In one embodiment, the maximum height Rz may be 2 to 40 μm, or 4 to 40 μm, or 6 to 40 μm.

In the electrolytic cell 100, the first nickel plating layer 14 is continuously provided on the first gasket contact surface 12e and the surface facing the anode chamber A of the first frame 10. By providing such a thick nickel plating layer on the surface of the first frame 10 facing the anode chamber A, the corrosion resistance in the oxygen gas atmosphere and oxygen gas-saturated alkaline water of the anode chamber is maintained at a level sufficient for long-term use. It becomes possible to increase it inexpensively. From the viewpoint of further improving corrosion resistance in the oxygen gas atmosphere of the anode chamber and oxygen gas-saturated alkaline water, the thickness of the nickel plating layer on the surface of the first frame 10 facing the anode chamber A is preferably 27 It is ㎛ or more, more preferably 30 ㎛ or more, particularly preferably 50 ㎛ or more. The upper limit of the thickness of the nickel plating layer on the surface of the first frame 10 facing the anode chamber A is not particularly limited, but is preferably, for example, 100 μm or less from the viewpoint of cost. The nickel plating layer on the surface facing the anode chamber A of the first frame 10 may be provided on the entire surface facing the anode chamber A of the first frame 10, or may be provided only on the liquid contact portion. do.

In one preferred embodiment, the first frame 10 includes at least one steel core 10a and a first nickel plating layer 14 provided on the surface of the core 10a. In the electrolytic cell 100, the steel core material 10a includes the steel core material 11a constituting the partition wall 11, the steel core material 12a constituting the flange portion 12, and the support member 13. ) includes the steel heart material (13a) constituting the The first nickel plating layer 14 is provided to be exposed at least to the gasket contact surface 12e of the flange portion 12, and is further continuous from the first gasket contact surface 12e, and is the surface of the core material 10a facing the anode chamber. It may be provided on the entire surface or may be provided on the entire surface of the core material 10a.

In one embodiment, such a first frame body 10 is provided with nickel plating on the steel core material 11a constituting the partition 11 and the steel core material 12a constituting the flange portion 12. It can be manufactured by doing this. Nickel plating may be applied to all core materials including the steel core material 11a constituting the partition 11 and the steel core material 12a constituting the flange portion 12, and the steel core material constituting the partition 11 may be plated with nickel. The core material 11a and the steel core material 12a constituting the flange portion 12 may be separately nickel-plated and then joined. In addition, when the first frame 10 is provided with the support member 13, it includes a steel core 11a constituting the partition 11 and a steel core 13a constituting the support member 13. Nickel plating may optionally be applied to all core materials further including the steel core material 12a constituting the flange portion 12, and may be applied separately to the steel core material 13a constituting the support member 13. After nickel plating, the support member 13 including the core material 13a and the nickel plating layer may be joined to the partition wall 11. In addition, as described above, the first flange portion 12 has an anolyte supply passage (not shown) that supplies the anolyte to the anode chamber A, and recovers the anolyte and the gas generated from the anode from the anode chamber A. It is equipped with an anolyte recovery channel (not shown). When the flange portion 12 is provided with a steel core material 12a, it is preferable that the nickel plating layer 14 is also provided on the inner surfaces of the anolyte supply passage and the anolyte recovery passage provided in the flange portion 12. . The nickel plating layer 14 is preferably provided at least on a liquid-contacting portion of the inner surface of the anolyte supply passage and the anolyte recovery passage provided in the flange portion 12, and may be provided on the entire inner surface.

FIG. 3 is a view in which only the second frame 20 is taken out from FIG. 1. In Fig. 3, elements already shown in Figs. 1 and 2 are given the same symbols as those in Figs. 1 and 2, and descriptions may be omitted. The second flange portion 22 has a second gasket contact surface 22e, which contacts the second gasket element 32 (see FIG. 1). The second frame 20 is provided with a second nickel plating layer 24 exposed to the second gasket contact surface 22e of the second flange portion 22. The thickness of the second nickel plating layer 24 at the second gasket contact surface 22e is preferably 27 μm or more, more preferably 30 μm, from the viewpoint of suppressing a decrease in the sealing properties of the catholyte and cathode chamber gas. It is ㎛ or more. The upper limit of the thickness is not particularly limited, but may be, for example, 100 μm or less from the viewpoint of manufacturing cost.

From the viewpoint of suppressing deterioration of the sealing properties of the catholyte and cathode chamber gas, the surface roughness of the second gasket contact surface 22e is preferably 10 μm or less as the arithmetic mean roughness Ra specified in JIS B0601, and more preferably It is 9㎛ or less, or 8㎛ or less. The lower limit of the arithmetic mean roughness Ra is not particularly limited, but may be 1 μm or more, or 2 μm or more in one embodiment, from the viewpoint of stability of fixation of the gasket and manufacturing cost. In one embodiment, the arithmetic mean roughness Ra may be 1 to 10 μm, or 1 to 9 μm, or 1 to 8 μm.

From the viewpoint of further suppressing the deterioration of the sealing properties of the catholyte and cathode chamber gas, the surface roughness of the second gasket contact surface 22e is the maximum height Rz specified in JIS B0601, and is preferably 40 μm or less, more preferably It is 35㎛ or less. The lower limit of the maximum height Rz is not particularly limited, but from the viewpoint of manufacturing cost, in one embodiment, it may be 2 μm or more, or 4 μm or more, or 6 μm or more, or 8 μm or more. In one embodiment, the maximum height Rz may be 2 to 40 μm, or 4 to 40 μm, or 6 to 40 μm.

In the electrolytic cell 100, the second nickel plating layer 24 is continuously provided on the second gasket contact surface 22e and the surface facing the cathode chamber C of the second frame 20. By providing a nickel plating layer on the surface of the second frame 20 facing the cathode chamber C, it becomes possible to increase the corrosion resistance under alkaline conditions in the cathode chamber to a sufficient level. On the surface of the second frame 20 facing the cathode chamber C, the nickel plating layer has a thickness that provides corrosion resistance capable of withstanding the alkaline conditions of the cathode chamber. The thickness is sufficient if it is 2㎛, preferably 10㎛ or more, more preferably 27㎛ or more, and in one embodiment, may be 30㎛ or more. The upper limit of the thickness of the nickel plating layer on the surface of the second frame 20 facing the cathode chamber C is not particularly limited, but is preferably, for example, 100 μm or less from the viewpoint of cost. The nickel plating layer on the surface facing the cathode chamber C of the second frame 20 may be provided on the entire surface facing the cathode chamber C of the second frame 20, or may be provided only on the liquid contact portion. do.

In one preferred embodiment, the second frame 20 includes at least one steel core material 20a and a second nickel plating layer 24 provided on the surface of the core material 20a. In the electrolytic cell 100, the steel core material 20a includes the steel core material 21a constituting the partition wall 21, the steel core material 22a constituting the flange portion 22, and the support member 23. ) includes the steel heart material 23a constituting the The second nickel plating layer 24 is provided to be exposed at least to the gasket contact surface 22e of the flange portion 22, and is further continuous from the second gasket contact surface 22e, and is the surface of the core material 20a facing the cathode chamber. It may be provided on the entire surface, or may be provided on the entire surface of the core material 20a.

In one embodiment, such a second frame body 20 is provided with nickel plating on the steel core material 21a constituting the partition 21 and the steel core material 22a constituting the flange portion 22. It can be manufactured by doing this. Nickel plating may be applied to all core materials including the steel core material 21a constituting the partition 21 and the steel core material 22a constituting the flange portion 22, and the steel core material constituting the partition 21 may be plated with nickel. The core material 21a and the steel core material 22a constituting the flange portion 22 may be separately nickel-plated and then joined. In addition, when the second frame 20 is provided with the support member 23, it includes a steel core 21a constituting the partition 21 and a steel core 23a constituting the support member 23. Nickel plating may optionally be applied to all core materials further including the steel core material 22a constituting the flange portion 22, and may be applied separately to the steel core material 23a constituting the support member 23. After performing nickel plating, the support member 23 including the core material 23a and the nickel plating layer may be joined to the partition wall 21. In addition, as described above, the second flange portion 22 also has a catholyte supply passage (not shown) for supplying catholyte to the cathode chamber C, and a catholyte supply passage (not shown) for supplying catholyte to the cathode chamber C. It is equipped with a catholyte recovery channel (not shown) to recover gas. When the flange portion 22 is provided with a steel core material 22a, it is preferable that the nickel plating layer 24 is also provided on the inner surfaces of the catholyte supply passage and the catholyte recovery passage provided in the flange portion 22. . The nickel plating layer 24 is preferably provided on at least the liquid contact portion of the inner surface of the catholyte supply flow path and the catholyte recovery flow path provided in the flange portion 22, and may be provided on the entire inner surface.

In another embodiment, the second frame 20 is formed by applying nickel plating to the steel core material 21a constituting the partition 21, and then forming the partition wall 21 provided with the core material 21a and the nickel plating layer. It can be manufactured by joining the flange portion 22 made of a non-metallic material. When the second frame 20 is provided with the support member 23, an integral body including the steel core material 21a constituting the partition 21 and the steel core material 23a constituting the support member 23. Nickel plating may be applied to the core material, or nickel plating may be performed separately on the steel core material 21a constituting the partition 21 and the steel core material 23a constituting the support member 23, and then You can join it.

In providing the first nickel plating layer 14 on the first frame 10, a known nickel plating method can be adopted. Nickel plating on the metal core material may be performed by electrolytic plating or electroless plating. However, electrolytic plating generally results in a rough surface, and electroless plating is easy to obtain a surface that satisfies the requirements of the arithmetic mean roughness Ra in the present invention. For this reason, electroless nickel plating can be preferably employed from the viewpoint of suppressing a decrease in the sealing properties of the anolyte and the anode chamber gas, and from the viewpoint of enhancing corrosion resistance in alkaline water with high oxygen gas activity. Electroless nickel plating can be performed by a known process. For example, for a metal core material, the pickling treatment process, degreasing treatment process, electrolytic degreasing treatment process, acid activation process, electroless nickel plating precipitation process, and post-plating heat treatment process are performed in the above order, thereby forming the metal core material. An electroless nickel plating layer can be formed on the surface. The electroless nickel plating may be electroless nickel-phosphorus plating or electroless nickel-boron plating, but from the viewpoint of further suppressing the deterioration of the sealing properties of the anode solution and the anode chamber gas, and the resistance in alkaline water with high oxygen gas activity. From the viewpoint of further increasing corrosion resistance, electroless nickel-phosphorus plating is preferable. The phosphorus content in the electroless nickel plating layer 14 is usually 1 to 13 mass%, and in one embodiment, it is 1 mass% or more and less than 5 mass%, or 5 mass% or more and less than 10 mass%, or 10 mass% or more. It may be 13% by mass or less. From the viewpoint of further suppressing the decline in the sealing properties of the anolyte and the anode chamber gas, and further improving the corrosion resistance in alkaline water with high oxygen gas activity, the phosphorus content in the electroless nickel plating layer 14 is preferably 5. ~13% by mass, and in one embodiment, may be 5% by mass or more and less than 10% by mass. In particular, when providing the first nickel plating layer 14 continuously on the first gasket contact surface 12e and the surface facing the anode chamber A of the first frame 10, the electrical resistance of the electrolytic cell 100 is further reduced. From the viewpoint of reducing and increasing energy efficiency, the phosphorus content in the electroless nickel plating layer 14 is preferably 5 mass% or more and less than 10 mass%.

When providing the second nickel plating layer 24 on the second frame 20, a known nickel plating method can be adopted. Nickel plating on the metal core material may be performed by electrolytic plating or electroless plating. However, from the viewpoint of further suppressing a decrease in the sealing properties of the catholyte and cathode chamber gas, and from the viewpoint of further improving corrosion resistance in alkaline water, electroless nickel plating can be preferably employed. Electroless nickel plating can be performed by a known process. For example, for a metal core material, the pickling treatment process, degreasing treatment process, electrolytic degreasing treatment process, acid activation process, electroless nickel plating precipitation process, and post-plating heat treatment process are performed in the above order, thereby forming the metal core material. An electroless nickel plating layer can be formed on the surface. The electroless nickel plating may be electroless nickel-phosphorus plating or electroless nickel-boron plating, but from the viewpoint of further suppressing the deterioration of the sealing properties of the catholyte and cathode chamber gas, and from the viewpoint of further improving corrosion resistance in alkaline water. In , electroless nickel-phosphorus plating is preferred. The phosphorus content in the electroless nickel plating layer 24 is usually 1 to 13 mass%, and in one embodiment, it is 1 mass% or more and less than 5 mass%, or 5 mass% or more and less than 10 mass%, or 10 mass% or more. It may be 13% by mass or less. From the viewpoint of further suppressing the decline in the sealing properties of the catholyte and cathode chamber gas, and further improving the corrosion resistance in alkaline water, the phosphorus content in the electroless nickel plating layer 24 is preferably 5 to 13% by mass. , in one embodiment, it may be 5 mass% or more and less than 10 mass%. In particular, when the second nickel plating layer 24 is continuously provided on the second gasket contact surface 22e and the surface facing the anode chamber A of the second frame 20, the electrical resistance of the electrolytic cell 100 is further reduced. From the viewpoint of reducing and increasing energy efficiency, the phosphorus content in the electroless nickel plating layer 24 is preferably 5 mass% or more and less than 10 mass%.

As the gasket 30 (see FIG. 1), a gasket that can be used in an electrolyzer for alkaline water electrolysis and has electrical insulation properties can be used without particular restrictions. 1 shows a cross section of the gasket 30. The gasket 30 has a flat shape, sandwiches the peripheral portion of the diaphragm 40, and is sandwiched between the first flange portion 12 and the second flange portion 22. The gasket 30 includes a first gasket element 31 that contacts the first flange portion 12 and the diaphragm 40, and a second gasket element that contacts the second flange portion 22 and the diaphragm 40. It has an element 32. In one embodiment, the first gasket element 31 and the second gasket element 32 are separate, separate gasket elements. In another embodiment, the first gasket element 31 and the second gasket element 32 may be joined at the outer edge to form an integrated gasket. With such an integrated gasket, it becomes possible to further improve the sealing properties of electrolyte and gas. The gasket 30 is preferably formed of an elastomer having alkali resistance. Examples of materials for the gasket 30 include 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), fluorine rubber (FR), isobutylene-isoprene rubber (IIR), urethane rubber (UR), chlorosulfonated polyethylene rubber (CSM), etc. Examples include elastomers. Additionally, when using a gasket material that does not have alkali resistance, a layer of a material that has alkali resistance may be provided on the surface of the gasket material by coating or the like.

As the diaphragm 40, an ion-permeable diaphragm that can be used in an electrolytic cell for alkaline water electrolysis can be used without particular restrictions. The diaphragm 40 preferably has low gas permeability, low electrical conductivity, and high strength. Examples of the diaphragm 40 include a porous membrane made of asbestos or modified asbestos, a porous membrane using a polysulfone polymer, a fabric using polyphenylene sulfide fibers, a fluorine-based porous membrane, and a porous membrane containing both inorganic and organic materials. Examples include porous membranes such as porous membranes using hybrid materials. In addition to these porous membranes, it is also possible to use an ion exchange membrane such as a fluorine-based membrane as the membrane 40.

As the anode 50, any anode that can be used in an electrolytic cell for alkaline water electrolysis can be used without particular restrictions. The anode 50 usually includes a conductive substrate and a catalyst layer that covers the surface of the substrate. The catalyst layer is preferably porous. As the conductive substrate for the anode 50, for example, nickel, nickel alloy, nickel iron, vanadium, molybdenum, copper, silver, manganese, platinum group elements, graphite, or chromium, or a combination thereof can be used. For the anode 50, a conductive substrate made 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 thereof, and may also contain an alloy of nickel and one or more other metals. It is particularly preferable that the catalyst layer is made of metallic nickel. Additionally, the catalyst layer may further contain chromium, molybdenum, cobalt, tantalum, zirconium, aluminum, zinc, platinum group elements, or rare earth elements, or a combination thereof. Rhodium, palladium, iridium, or ruthenium, or a combination thereof may be further supported on the surface of the catalyst layer as an additional catalyst. The conductive substrate of the anode 50 may be a rigid substrate or a flexible substrate. Examples of the rigid conductive substrate constituting the anode 50 include expanded metal and punched metal. In addition, examples of the flexible conductive substrate constituting the anode 50 include a mesh woven (or knitted) with metal wire.

As the cathode 60, any cathode that can be used in an electrolytic cell for alkaline water electrolysis can be used without particular restrictions. The cathode 60 usually includes a conductive substrate and a catalyst layer that covers the surface of the substrate. As a conductive base material for the cathode 60, for example, nickel, nickel alloy, stainless steel, mild steel, nickel alloy, or stainless steel or mild steel plated with nickel can be preferably used. As the catalyst layer of the cathode 60, a catalyst layer made of noble metal oxide, nickel, cobalt, molybdenum, or manganese, or their oxides, or noble metal oxide can be preferably used. The conductive substrate constituting the cathode 60 may be, for example, a rigid substrate or a flexible substrate. Examples of the rigid conductive substrate constituting the cathode 60 include expanded metal and punched metal. Additionally, examples of the flexible conductive substrate constituting the cathode 60 include a mesh woven (or knitted) with metal wire.

According to the electrolytic cell 100, the first frame 10 defining the anode chamber A has a thickness of 27 μm or more, more preferably exposed to the gasket contact surface 12e of the first flange portion 12. By providing a first nickel plating layer 14 of 30 μm or more and having a surface roughness of the gasket contact surface 12e of 10 μm or less as an arithmetic mean roughness Ra, it is possible to suppress a decrease in the sealing properties of the anolyte solution and the anode chamber gas. do.

In the above description of the present invention, an electrolytic cell 100 having a gap between the anode 50 and the diaphragm 40 and between the cathode 60 and the diaphragm 40 is given as an example, but the present invention It is not limited to the form in question. For example, instead of the rigid negative electrode 60, a flexible negative electrode is provided in the negative electrode chamber, and is disposed between the negative electrode current collector held by the support member 23 and the negative electrode current collector and the diaphragm 40. It is provided with a conductive elastic body supported throughout and a flexible cathode disposed between the elastic body and the diaphragm 40, and the elastic body presses the flexible cathode toward the diaphragm 40 and the anode 50, thereby forming a flexible cathode. It is also possible to use a so-called zero-gap type alkaline water electrolyzer in which the cathode and the diaphragm 40 are in direct contact, and the diaphragm 40 and the anode 50 are in direct contact.

In the above description of the present invention, the first nickel plating layer 14 is provided continuously on the first gasket contact surface 12e and the surface facing the anode chamber A of the first frame 10. Although the electrolytic cell 100 is used as an example, the present invention is not limited to this form. For example, in the first frame 10, it is also possible to use an alkaline water electrolyzer in which a nickel plating layer is provided only on the first gasket contact surface 12e. In addition, for example, the first nickel plating layer 14 is exposed to the first gasket contact surface 12e, and a third nickel plating layer that is not continuous with the first nickel plating layer 14 is provided on the first frame. It is also possible to use an alkaline water electrolyzer of the type provided on the surface facing the anode chamber A of the sieve 10.

In the above description of the present invention, the second nickel plating layer 24 is continuously provided on the second gasket contact surface 22e and the surface facing the cathode chamber C of the second frame 20. Although the electrolytic cell 100 is used as an example, the present invention is not limited to this form. For example, in the second frame 20, it is also possible to use an alkaline water electrolyzer in which a nickel plating layer is provided only on the second gasket contact surface 22e. In addition, for example, the second nickel plating layer 24 is provided exposed to the second gasket contact surface 22e, and a fourth nickel plating layer that is not continuous with the second nickel plating layer 24 is provided on the second frame. It is also possible to use an alkaline water electrolyzer of the type provided on the surface facing the anode chamber (C) of the sieve.

In the above description of the present invention, the second frame 20 defining the cathode chamber C is provided in an electrolytic cell ( 100) was used as an example, but the present invention is not limited to this form. For example, it is possible for the second frame 20 to be an alkaline water electrolyzer in which the second gasket contact surface 22e does not have a nickel plating layer.

In the above description of the present invention, the first frame 10 is provided to protrude from the first partition 11 into the anode chamber A, and includes a conductive support member 13 for supporting the anode 50. Although the electrolytic cell 100 is provided as an example, the present invention is not limited to this form. For example, it is also possible to use an alkaline water electrolyzer without the support member 13. An example of such an alkaline water electrolyzer is provided with a first conductive elastic body disposed between the first partition 11 and the anode 50 instead of the conductive support member 13, and the first conductive elastic body is provided. , an alkaline water electrolyzer in which the anode 50 is pressed from the back toward the diaphragm 40 can be mentioned.

In the above description of the present invention, the second frame 20 is provided to protrude from the second partition 21 into the cathode chamber C, and includes a conductive support member 23 for supporting the cathode 60. Although the electrolytic cell 100 is provided as an example, the present invention is not limited to this form. For example, it is also possible to use an alkaline water electrolyzer that does not include the support member 23. An example of such an alkaline water electrolyzer is provided with a second conductive elastic body disposed between the second partition 21 and the cathode 60 instead of the conductive support member 13, and the second conductive elastic body is provided. , an alkaline water electrolyzer in which the cathode 60 is pressed from the back toward the diaphragm 40 can be cited.

In the above description of the present invention, the electrolytic cell 100 in the form of a single cell is used as an example, but the present invention is not limited to this form. For example, a plurality of electrolytic cells composed of a set of an anode chamber (A) defined by the first frame 10 and a cathode chamber (C) defined by the second frame 20 are connected in series. It is also possible to use an electrolyzer in the form of a connection. In addition, for example, the flange portion 12 of the first frame 10 extends to the opposite side of the partition wall 11 (right side in Fig. 1) to form an electrolytic cell adjacent to the partition wall 11. The cathode chamber may be further defined, and the flange portion 22 of the second frame 20 may extend to the opposite side of the partition 21 (left side of the drawing in FIG. 1) to form the partition wall 21 and the partition wall 21. The anode chambers of the electrolytic cells adjacent together may be further defined. FIG. 4 is a diagram schematically explaining an alkaline water electrolyzer 200 (hereinafter sometimes referred to as “electrolyzer 200”) according to another such embodiment. In Fig. 4, elements already shown in Figs. 1 to 3 are given the same symbols as those in Figs. 1 to 3, and descriptions may be omitted. The electrolytic cell 200 is an alkaline water electrolytic cell having a structure in which an electrolytic cell composed of an anode chamber (A1) and a cathode chamber (C1) and an electrolytic cell composed of an anode chamber (A2) and a cathode chamber (C2) are connected in series. The electrolytic cell 200 includes a first frame 10 connected to an anode terminal and defining an anode chamber A1; a second frame (20) connected to the cathode terminal and defining a cathode chamber (C2); At least one third frame 210 disposed between the first frame 10 and the second frame 20; Each is provided with a plurality of gaskets 30, a diaphragm 40, an anode 50, and a cathode 60. The diaphragm 40 is between the first frame 10 and the third frame 210 adjacent to it, and between the second frame 20 and the third frame 210 adjacent to this. In the case where there is a plurality of third frames 210, they are disposed between two adjacent third frames 210, and are each sandwiched by a gasket 30. The anode chamber A1 and the cathode chamber C1 are defined by the first frame 10 and the third frame 210, and the anode chamber A1 and the cathode chamber C1 are defined by the third frame 210 and the second frame 20. A chamber (A2) and a cathode chamber (C2) are defined. An anode 50 is disposed in each of the anode chambers A1 and A2, and a cathode 60 is disposed in each of the cathode chambers C1 and C2.

The first frame 10 and the second frame 20 are, respectively, the first frame 10 (FIG. 2) and the second frame 20 in the electrolytic cell 100 (FIG. 1) described above. ) has the same configuration as (Figure 4). The partition 11 of the first frame 10 is connected to the positive terminal, and the partition 21 of the second frame 20 is connected to the negative terminal. In addition, the anode 50 is held by the support member 13 in the anode chamber A1 defined by the first frame 10, and is held in the cathode chamber C2 defined by the second frame 20. The same applies to the above in that the cathode 20 is held by the support member 23.

The third frame 210 is a bipolar electrolytic element having a structure in which the first frame 10 and the second frame 20 are integrated. That is, the third frame 210 includes a conductive partition 211 and a first flange portion 212 extending from the outer periphery of the partition 211 toward the second frame 20 (left side in FIG. 4). ) and a second flange portion 222 extending from the outer periphery of the partition wall 211 toward the first frame 10 (right side of the drawing in FIG. 4). In the third frame 210, the first flange portion 212 and the second flange portion 222 are formed integrally. In the third frame 210, on the first frame 10 side of the partition 211 (right side in Fig. 4), a conductive support member (second support member) 223 is provided from the partition 211. It is provided protruding. The support member 223 holds the cathode 60 in the cathode chamber C1 and is electrically connected to the cathode 60 and the partition wall 211 disposed in the cathode chamber C1. In the third frame 210, on the second frame 20 side of the partition 211 (left side in FIG. 4), a conductive support member (first support member) 213 is provided from the partition 211. It is provided protruding. The support member 213 holds the anode 50 in the anode chamber A2 and is electrically connected to the anode 50 disposed in the anode chamber A2 and the partition wall 211 of the third frame 210. It's running smoothly. The configuration of the partition 211, the first support member 213, and the second support member 223 is similar to the partition 11 and the first support member 13 described above with respect to the electrolytic cell 100 (FIG. 1). , and the second support member 23. The configuration of the first flange portion 212 and the second flange portion 222 is similar to that of the electrolytic cell 100 (FIG. 1) except that the first flange portion 212 and the second flange portion 222 are formed integrally. ) are the same as the first flange portion 12 and the second flange portion 22 described above, respectively. The first flange portion 212 of the third frame 210 defines the anode chamber A2 together with the partition 211, the partition 40, and the first gasket element 31, and the third frame 210 defines the anode chamber A2. The second flange portion 222 of the sieve 210 defines the cathode chamber C1 together with the partition wall 211, the diaphragm 40, and the second gasket element 32.

FIG. 5 is a diagram in which only the third frame 210 is extracted from FIG. 4 . In Fig. 5, elements already shown in Figs. 1 to 4 are given the same symbols as those in Figs. 1 to 4, and descriptions may be omitted. The first flange portion 212 of the third frame 210 has a first gasket contact surface 212e that contacts the first gasket element 31 (see FIG. 1). The third frame 210 includes a first nickel plating layer 214 exposed to the first gasket contact surface 212e of the first flange portion 212. The thickness of the first nickel plating layer 214 at the first gasket contact surface 212e is determined from the viewpoint of suppressing a decrease in the sealing properties of the anolyte and the anode chamber gas, and corrosion resistance in alkaline water with high oxygen gas activity. From the viewpoint of long-term height, it is 27 μm or more, more preferably 30 μm or more. The upper limit of the thickness is not particularly limited, but may be, for example, 100 μm or less from the viewpoint of manufacturing cost.

From the viewpoint of suppressing the deterioration of the sealing properties of the anolyte and the anode chamber gas, and from the viewpoint of increasing corrosion resistance in alkaline water with high oxygen gas activity over a long period of time, the surface roughness of the first gasket contact surface 212e is in accordance with JIS B0601. The prescribed arithmetic mean roughness Ra is 10 μm or less, preferably 9 μm or less, or 8 μm or less. The lower limit of the arithmetic mean roughness Ra is not particularly limited, but may be 1 μm or more, or 2 μm or more in one embodiment, from the viewpoint of stability of fixation of the gasket and manufacturing cost. In one embodiment, the arithmetic mean roughness Ra may be 1 to 10 μm, or 1 to 9 μm, or 1 to 8 μm.

From the viewpoint of further suppressing the deterioration of the sealing properties of the anolyte and the anode chamber gas, and further improving the corrosion resistance in alkaline water with high oxygen gas activity, the surface roughness of the first gasket contact surface 212e is specified in JIS B0601. The maximum height Rz is preferably 40 μm or less, more preferably 35 μm or less. The lower limit of the maximum height Rz is not particularly limited, but from the viewpoint of manufacturing cost, in one embodiment, it may be 2 μm or more, or 4 μm or more, or 6 μm or more, or 8 μm or more. In one embodiment, the maximum height Rz may be 2 to 40 μm, or 4 to 40 μm, or 6 to 40 μm.

In the electrolytic cell 200, the first nickel plating layer 214 is continuously provided on the first gasket contact surface 212e and the surface facing the anode chamber A2 of the third frame 210. By providing the third frame 210 with such a thick nickel plating layer on the liquid-contacting portion of the anode chamber A2, corrosion resistance in the oxygen gas atmosphere and oxygen gas-saturated alkaline water of the anode chamber is increased to a level sufficient for long-term use. It becomes possible. From the viewpoint of further improving corrosion resistance in the oxygen gas atmosphere of the anode chamber and oxygen gas-saturated alkaline water, the thickness of the nickel plating layer on the surface of the third frame 210 facing the anode chamber A2 is preferably 27 It is ㎛ or more, more preferably 30 ㎛ or more, particularly preferably 50 ㎛ or more. The upper limit of the thickness of the nickel plating layer on the surface of the third frame 210 facing the anode chamber A2 is not particularly limited, but is preferably, for example, 100 μm or less from the viewpoint of cost. The nickel plating layer on the surface facing the anode chamber A2 of the third frame 210 may be provided on the entire surface facing the anode chamber A2 of the third frame 210, or may be provided only on the liquid contact portion. do.

In one preferred embodiment, the third frame 210 includes at least one steel core material 210a and a first nickel plating layer 214 provided on the surface of the core material 210a. In the electrolytic cell 200, the steel core material 210a of the third frame 210 includes the steel core material 211a constituting the partition 211, the first flange portion 212, and the second flange portion. It includes steel core members 212a and 222a respectively constituting 222, and steel core members 213a and 223a respectively constituting the first support member 213 and the second support member 223. In the third frame 210, the steel core material 212a constituting the first flange portion 212 and the steel core material 222a constituting the second flange portion 222 are formed as one piece. there is. The first nickel plating layer 214 is provided to be exposed to at least the gasket contact surface 212e of the first flange portion 212, and is further continuous from the first gasket contact surface 212e, in the core material 210a, the anode chamber ( It may be provided on the entire surface facing A2), or may be provided on the entire surface of the core material 210a.

The second flange portion 222 of the third frame 210 has a second gasket contact surface 222e that contacts the second gasket element 32 (see FIG. 4). The third frame 210 is provided with a second nickel plating layer 224 exposed to the second gasket contact surface 222e of the second flange portion 222. The thickness of the second nickel plating layer 224 at the second gasket contact surface 222e is preferably 27 μm or more, more preferably 30 μm, from the viewpoint of suppressing a decrease in the sealing properties of the catholyte and cathode chamber gas. It is more than ㎛. The upper limit of the thickness is not particularly limited, but may be, for example, 100 μm or less from the viewpoint of manufacturing cost.

From the viewpoint of suppressing the deterioration of the sealing properties of the catholyte and cathode chamber gas, the surface roughness of the second gasket contact surface 222e is preferably 10 μm or less as the arithmetic mean roughness Ra specified in JIS B0601, and more preferably It is 9㎛ or less, or 8㎛ or less. The lower limit of the arithmetic mean roughness Ra is not particularly limited, but may be 1 μm or more, or 2 μm or more in one embodiment, from the viewpoint of stability of fixation of the gasket and manufacturing cost. In one embodiment, the arithmetic mean roughness Ra may be 1 to 10 μm, or 1 to 9 μm, or 1 to 8 μm.

From the viewpoint of further suppressing the deterioration of the sealing properties of the catholyte and cathode chamber gas, the surface roughness of the second gasket contact surface 222e is the maximum height Rz specified in JIS B0601, and is preferably 40 μm or less, more preferably It is 35㎛ or less. The lower limit of the maximum height Rz is not particularly limited, but from the viewpoint of manufacturing cost, in one embodiment, it may be 2 μm or more, or 4 μm or more, or 6 μm or more, or 8 μm or more. In one embodiment, the maximum height Rz may be 2 to 40 μm, or 4 to 40 μm, or 6 to 40 μm.

In the electrolytic cell 200, the second nickel plating layer 224 is continuously provided on the second gasket contact surface 222e and the surface facing the cathode chamber C1 of the third frame 210. By providing a nickel plating layer on the surface of the third frame 210 facing the cathode chamber C1, it becomes possible to increase corrosion resistance under alkaline conditions in the cathode chamber to a sufficient level. On the surface of the third frame 210 facing the cathode chamber C1, the nickel plating layer has a thickness that provides corrosion resistance capable of withstanding the alkaline conditions of the cathode chamber. The thickness is sufficient if it is 2㎛, preferably 10㎛ or more, more preferably 27㎛ or more, and in one embodiment, may be 30㎛ or more. The upper limit of the thickness of the nickel plating layer on the surface of the third frame 210 facing the cathode chamber C1 is not particularly limited, but is preferably, for example, 100 μm or less from the viewpoint of cost. The nickel plating layer on the surface facing the cathode chamber C1 of the third frame 210 may be provided on the entire surface facing the cathode chamber C1 of the third frame 210, or may be provided only on the liquid contact portion. do.

In one preferred embodiment, the third frame body 210 includes at least one steel core material 210a, and the first nickel plating layer 214 and the second nickel plating layer provided on the surface of the core material 210a. Includes (224). In the electrolytic cell 200, the steel core material 210a of the third frame 210 includes the steel core material 211a constituting the partition 211, the first flange portion 212, and the second flange portion. It includes steel core members 212a and 222a respectively constituting 222, and steel core members 213a and 223a respectively constituting the first support member 213 and the second support member 223. In the third frame 210, the steel core material 212a constituting the first flange portion 212 and the steel core material 222a constituting the second flange portion 222 are formed as one piece. there is. The second nickel plating layer 224 is provided to be exposed to at least the gasket contact surface 222e of the second flange portion 222, and is further continuous from the second gasket contact surface 222e, in the core material 210a, the cathode chamber ( It may be provided on the entire surface facing C1), or may be provided on the entire surface of the core material 210a.

In one embodiment, such a third frame body 210 includes a steel core material 211a constituting the partition 211 and a steel core material 212a constituting the first flange portion 212, and Optionally, it can be manufactured by plating nickel on the steel core material 222a constituting the second flange portion 222. Nickel plating may be applied to all core materials including the steel core material 211a constituting the partition 211 and the steel core materials 212a and 222a constituting the flange portions 212 and 222, and the partition wall 211 Nickel plating is performed separately on the steel core material 211a constituting the steel core material 212a constituting the first flange portion 212 and the steel core material 222a constituting the second flange portion 222. After performing this, the two may be joined. In addition, when the third frame 210 is provided with support members 213 and 223, the steel core material 211a constituting the partition 211 and the steel core material constituting the support members 213 and 223 ( Nickel plating may be applied to all core materials including (213a, 223a) and optionally further including steel core materials (212a, 222a) constituting the flange portions (212, 222), and the support members (213, 223) After separately nickel plating the steel core materials 213a and 223a constituting the first support member 213 including the core material 213a and a nickel plating layer, and the first support member 213 including the core material 223a and a nickel plating layer. The two support members 223 may each be joined to the partition wall 211.

In addition, although not shown in FIGS. 4 and 5, in the third frame 210, the flange portions 212 and 222 include an anolyte supply passage (not shown) that supplies the anolyte to the anode chamber A2. , an anolyte recovery passage (not shown) that recovers the anolyte and the gas generated from the anode from the anolyte (A2), a catholyte supply passage (not shown) that supplies the catholyte to the cathode chamber (C1), and a cathode chamber. (C1) is provided with a catholyte recovery passage (not shown) for recovering the catholyte and the gas generated from the cathode. In the electrolyzer 200, the anolyte supply flow path and the anolyte recovery flow path provided in the third frame 210 pass through the first through holes (not shown) provided in the gasket 30 and the diaphragm 40, respectively. They are in fluid communication with the anolyte supply flow path and the anolyte recovery flow path provided in the frame 10, respectively. In addition, the catholyte supply flow path and the catholyte recovery flow path provided in the third frame body 210 are connected to the second frame body 20 through through holes (not shown) provided in the gasket 30 and the diaphragm 40, respectively. It is in fluid communication with the catholyte supply flow path and the catholyte recovery flow path provided in . However, the anolyte supply passage, the anolyte recovery passage and the cathode chambers C1 and C2 are not in fluid communication, so there is no flow of electrolyte and gas between them. Additionally, the catholyte supply flow path, the catholyte recovery flow path, and the anode chambers A1 and A2 are not in fluid communication, so there is no flow of electrolyte solution and gas between them. When the flange portions 212 and 222 are provided with steel core materials 212a and 222a, the nickel plating layer 214 is also formed on the inner surfaces of the anolyte supply passage and the anolyte recovery passage provided in the flange portions 212 and 222. It is preferable that the nickel plating layer 224 be provided on the inner surfaces of the catholyte supply flow path and the catholyte recovery flow path provided in the flange portions 212 and 222. The nickel plating layer 214 is preferably provided on at least the liquid contact portion of the inner surfaces of the anolyte supply flow path and the anolyte recovery flow path provided in the flange portions 212 and 222, and may be provided on the entire inner surface. In addition, the nickel plating layer 224 is preferably provided on at least the liquid contact portion of the inner surface of the catholyte supply flow path and the catholyte recovery flow path provided in the flange portions 212 and 222, and may be provided on the entire inner surface. . In the third frame 210, the first nickel plating layer 214 and the second nickel plating layer 224 may be one continuous nickel plating layer. For example, the first nickel plating layer 214 and the second nickel plating layer 224 are an anolyte supply flow path and an anolyte recovery flow path provided in the first flange part 212 and the second flange part 222, and the cathode. A continuous nickel plating layer may be formed through the inner surfaces of the liquid supply flow path and the catholyte recovery flow path. Additionally, for example, the first nickel plating layer 214 and the second nickel plating layer 224 may form a continuous nickel plating layer through the outer peripheral surfaces of the flange portions 212 and 222.

According to the electrolytic cell 200, the first frame 10 defining the anode chamber A1 has a thickness of 27 μm or more, more preferably exposed to the gasket contact surface 12e of the first flange portion 12. A third frame body 10 having a first nickel plating layer 14 of 30 μm or more, having a surface roughness of the gasket contact surface 12e of 10 μm or less as an arithmetic mean roughness Ra, and defining the anode chamber A2. ) is provided with a first nickel plating layer 214 exposed to the gasket contact surface 212e of the first flange portion 212 and has a thickness of 27 ㎛ or more, more preferably 30 ㎛ or more, and the gasket contact surface 212e When the surface roughness is 10 μm or less as the arithmetic mean roughness Ra, it is possible to suppress a decrease in the sealing properties of the anolyte and the anode chamber gas.

[Example]

Hereinafter, the present invention will be described in more detail based on examples and comparative examples. However, the present invention is not limited to these examples.

(measurement method)

In the following examples and comparative examples, the plating layer thickness was measured using an electronic thickness meter (LE-373, manufactured by Getsuto Chemical Co., Ltd.). Surface roughness was measured using a surface roughness shape measuring device (Surfcom 480A, manufactured by Tokyo Seimitsu).

(Production of samples)

As a nickel plating object, a steel plate (30 mm long x 50 mm wide x 10 mm thick) made of rolled steel for welded structures (SM400B) that was chamfered on the edge was used. As bolt holes required to insert the gasket, holes with a diameter of 5 mm were provided at the four corners. A plurality of types of steel sheet samples, each of which had the surface roughness of the steel sheet intentionally adjusted so that the surface roughness after plating would change, were produced. Steel plate samples with different surface roughness were produced by shot blast processing using brown alumina (No. 2000 to 4000) as an abrasive. The surface roughness in shot blast processing was adjusted by adjusting the number of abrasives and the shot time. Nickel plating was performed on each steel sheet sample using electroless nickel plating or electric nickel plating, and nickel-plated steel sheet samples with different plating thicknesses and surface roughness were produced.

The electroless plating process was performed according to the general electroless nickel plating process procedure. The steel plate sample was immersed in an acetone solution and ultrasonically degreased for 10 minutes. After that, pure water washing was performed, and acid washing was performed by immersing it in 10% diluted hydrochloric acid for 5 minutes. After washing the steel sheet with pure water, it was immersed in an electroless nickel-phosphorus plating solution (medium phosphorus type, “Top Neuron” (registered trademark) manufactured by Okuno Seiyaku Kogyo Corporation). The temperature of the plating solution was maintained at 90°C. While the steel sheet was immersed in the plating solution, the plating solution was gently stirred. In order to suppress changes in the plating bath composition, the plating solution was changed appropriately. The plating film thickness was adjusted by changing the immersion time of the steel sheet in the plating solution. After pulling the steel sheet from the plating solution, it was washed with pure water and dried to obtain a test piece plated with electroless nickel. The plating thickness and surface roughness (arithmetic average roughness Ra and maximum height Rz) of the obtained test pieces were measured.

The electroplating process was performed according to the general electronickel plating process procedure. The steel plate sample was immersed in an acetone solution and ultrasonically degreased for 10 minutes. After that, pure water washing was performed, and acid washing was performed by immersing it in 10% diluted hydrochloric acid for 5 minutes. After washing the steel sheet with pure water, it was immersed in an electric nickel plating bath (Watt bath, nickel sulfate 280 g/L, nickel chloride 45 g/L, boric acid 35 g/L), and the electroplating current density was set to 10 A/L. The nickel plating layer was electrodeposited in dm2. During the plating process, the temperature of the plating bath liquid was maintained at 45°C, and the plating liquid was gently stirred. In order to suppress changes in the plating bath composition, the plating solution was changed appropriately. After the nickel plating layer was electrodeposited until the predetermined plating film thickness was obtained, the steel sheet was lifted from the plating bath, washed with pure water and dried, and a test piece electroplated with nickel was obtained. The plating thickness and surface roughness (arithmetic average roughness Ra and maximum height Rz) of the obtained test pieces were measured.

Two test pieces with the same surface roughness, which were subjected to electroless nickel plating or electric nickel plating, were fitted with a flat gasket (made of EPDM, 30 mm long kgf/cm2) to produce a sample for immersion.

<Examples 1 to 5 and Comparative Examples 1 to 5>

(Alkali immersion - salt spray test (1))

The properties of each immersion sample before and after plating are shown in Tables 1 and 2. Each sample for immersion was immersed in an alkaline solution (30 mass% potassium hydroxide aqueous solution, 100°C) for 240 hours. This is a more stringent condition for metal corrosion than a typical electrolyte solution in an alkaline water electrolyzer. After the sample for immersion was lifted from the alkaline solution, it was dismantled, washed with water, and dried. For the surface where the test piece was in contact with the gasket (test surface), a salt spray test using a neutral sodium chloride aqueous solution was performed in accordance with JIS Z2371, and the surface condition of the test surface 72 hours after the salt water spray was observed, 1 It was rated at ~3. The evaluation criteria are as follows.

3: No occurrence of red rust was observed at all, and no discoloration was observed.

2: No occurrence of red rust was observed, but discoloration was observed.

1: Both red rust and discoloration observed on a large surface

The results are shown in Tables 1 and 2.

[Table 1]

[Table 2]

In the alkali immersion-salt spray test described above, if there are areas where nickel plating is deteriorated on the surface to be tested, the score deteriorates. And, when the test piece is fastened together with the gasket and immersed in the alkaline liquid, the worse the sealing performance between the test piece and the gasket, the larger the amount of alkaline liquid intrudes into a wider area between the test piece and the gasket, so that the surface to be tested is Nickel plating is prone to deterioration over a wide area. When the nickel plating deteriorates, more alkaline liquid penetrates into the deteriorated areas, creating a vicious cycle in which the sealing performance further deteriorates. All of the test pieces of Examples 1 to 5 showed good results in the alkali immersion-salt spray test.

The test pieces of Comparative Examples 1 to 5, in which the surface roughness of the steel sheet after plating exceeded 10 ㎛ as the arithmetic mean roughness Ra, showed poor results in the alkali immersion-salt spray test, even though the plating thickness was 27 ㎛ or more.

<Example 6 and Comparative Examples 6 to 7>

(Alkali immersion - salt spray test (2))

Table 3 shows the properties of each immersion sample before and after plating. Each sample for immersion was immersed in an alkaline solution (48 mass% potassium hydroxide aqueous solution, 120°C) for 2000 hours. This is a more stringent condition for metal corrosion than the conditions in Examples 1 to 5 and Comparative Examples 1 to 5. After the sample for immersion was lifted from the alkaline solution, it was dismantled, washed with water, and dried. A salt spray test was performed in the same manner as above on the surface where the test piece was in contact with the gasket (test surface), and the surface condition of the test surface after 72 hours was evaluated. The results are shown in Table 3.

[Table 3]

Similarly, in the alkali immersion-salt spray test performed on Example 6 and Comparative Examples 6 to 7, if there are areas where nickel plating is deteriorated on the test surface, the rating deteriorates. And, when the test piece is fastened together with the gasket and immersed in the alkaline liquid, the worse the sealing performance between the test piece and the gasket, the larger the amount of alkaline liquid intrudes into a wider area between the test piece and the gasket, so that the surface to be tested is Nickel plating is prone to deterioration over a wide area. When the nickel plating deteriorates, more alkaline liquid penetrates into the deteriorated areas, creating a vicious cycle in which the sealing performance further deteriorates. In this test, compared to the tests of Examples 1 to 5 and Comparative Examples 1 to 5, the corrosiveness of the alkaline solution is higher and the alkali immersion time is longer, so this vicious cycle is more likely to proceed. However, the test piece of Example 6 showed good performance in the alkali immersion-salt spray test.

The test pieces of Comparative Examples 6 to 7, where the plating thickness was less than 27㎛, showed poor results in the alkali immersion-salt water spray test, even though the surface roughness of the steel sheet after plating was 10㎛ or less as the arithmetic mean roughness Ra.

From the above results, it is believed that, according to the alkaline water electrolyzer of the present invention, it is possible to suppress the deterioration of the sealing properties of the anolyte and the anode chamber gas even in the anode chamber where the conditions for metal corrosion are strict. In addition, it is believed that even under strict conditions regarding metal corrosion, nickel plating on the gasket contact surface of the flange section can prolong the lifespan.

10: first frame
20: Second frame
210: Third frame
10a, 20a, 210a: (forced) heartwood
14, 214: first nickel plating layer
24, 224: second nickel plating layer
11, 21, 211: (conductive) septum
12, 212: first flange portion
22, 222: second flange portion
13, 213, 23, 223: (conductive) support absence
30: gasket
31: first gasket element
32: second gasket element
40: (ionically permeable) diaphragm
50: anode
60: cathode
100, 200: Electrolyzer
A, A1, A2: Anode chamber
C, C1, C2: cathode chamber

Claims (14)

A first frame body having a conductive first partition and a first flange portion provided on the outer periphery of the first partition, and defining an anode chamber;
A second frame body having a conductive second barrier rib and a second flange portion provided on the outer periphery of the second barrier rib, and defining a cathode chamber;
an ion-permeable diaphragm disposed between the first frame and the second frame and dividing the anode chamber and the cathode chamber;
a gasket sandwiched between a first flange portion of the first frame and a second flange portion of the second frame and maintaining the diaphragm;
an anode disposed in the anode chamber and electrically connected to the first partition,
A cathode disposed in the cathode chamber and electrically connected to the second partition wall.
Equipped with
The gasket is,
a first gasket element contacting the first flange portion and the diaphragm;
A second gasket element contacting the second flange portion and the diaphragm.
Equipped with
The first flange portion has a first gasket contact surface that contacts the first gasket element,
The first frame body has a first nickel plating layer with a thickness of 27 μm or more provided and exposed to the first gasket contact surface of the first flange portion,
An alkaline water electrolyzer wherein the surface roughness of the first gasket contact surface is 10 μm or less as an arithmetic average roughness Ra. According to paragraph 1,
An alkaline water electrolyzer wherein the surface roughness of the first gasket contact surface is 40 μm or less as a maximum height Rz. According to claim 1 or 2,
An alkaline water electrolyzer wherein the first nickel plating layer is an electroless nickel plating layer. According to claim 1 or 2,
The first frame body,
At least one steel first core,
The first nickel plating layer provided on the surface of the first core material
Containing an alkaline water electrolyzer. According to claim 1 or 2,
An alkaline water electrolyzer wherein the first nickel plating layer is continuously provided on the first gasket contact surface and the surface facing the anode chamber of the first frame. According to claim 1 or 2,
An alkaline water electrolyzer wherein the first nickel plating layer has a thickness of 30 to 100 μm. According to claim 1 or 2,
The first frame is,
A conductive support member provided to protrude from the first partition into the anode chamber and supports the anode.
An alkaline water electrolyzer further comprising: According to claim 1 or 2,
The second flange portion has a second gasket contact surface that contacts the second gasket element,
The second frame body has a second nickel plating layer with a thickness of 27 μm or more exposed to the second gasket contact surface of the second flange portion,
An alkaline water electrolyzer wherein the surface roughness of the second gasket contact surface is 10 μm or less as an arithmetic average roughness Ra. According to clause 8,
An alkaline water electrolyzer wherein the surface roughness of the second gasket contact surface is 40 μm or less as a maximum height Rz. According to clause 8,
An alkaline water electrolyzer wherein the second nickel plating layer is an electroless nickel plating layer. According to clause 8,
The second frame body,
at least one second heartwood of the force,
The second nickel plating layer provided on the surface of the second core material
Containing an alkaline water electrolyzer. According to clause 8,
An alkaline water electrolyzer wherein the second nickel plating layer is continuously provided on the second gasket contact surface and the surface of the second frame facing the cathode chamber. According to clause 8,
An alkaline water electrolyzer wherein the second nickel plating layer has a thickness of 50 to 100 μm. According to claim 1 or 2,
The second frame is,
A conductive support member provided to protrude from the second partition into the cathode chamber and supports the cathode.
An alkaline water electrolyzer further comprising:

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