阅读说明：本技术 电极结构体、电解单元和电解槽 (Electrode structure, electrolysis cell and electrolytic cell ) 是由 松冈卫 土田和幸 甲斐直幸 和田一也 角佳典 于 2019-06-19 设计创作，主要内容包括：本发明涉及电极结构体、电解单元和电解槽。本发明的目的在于提供能够在电解单元内部降低损伤的电极结构体、使用了该电极结构体的电解单元和电解槽。本发明的电极结构体具备：电极、具有与上述电极对置的第1面以及与该第1面相反一侧的第2面的集电板、以及位于上述电极与上述集电板的上述第1面之间且具有导电性的弹性体,上述电极的周边部的至少一部分和上述弹性体的周边部的至少一部分按照跨过上述集电板的缘部而位于上述第2面上的方式进行延伸。(The invention relates to an electrode structure, an electrolysis cell and an electrolysis cell. The invention aims to provide an electrode structure capable of reducing damage in an electrolysis cell, and an electrolysis cell and an electrolysis bath using the electrode structure. The electrode structure of the present invention includes: the electrode assembly includes an electrode, a current collector plate having a 1 st surface facing the electrode and a 2 nd surface opposite to the 1 st surface, and an elastic body having conductivity and located between the electrode and the 1 st surface of the current collector plate, wherein at least a part of a peripheral portion of the electrode and at least a part of a peripheral portion of the elastic body extend so as to straddle an edge portion of the current collector plate and be located on the 2 nd surface.)

1. An electrode structure, comprising:

an electrode,

A collector plate having a 1 st surface facing the electrode and a 2 nd surface opposite to the 1 st surface, and

an elastic body having conductivity and located between the electrode and the 1 st surface of the collector plate,

at least a part of the peripheral portion of the electrode and at least a part of the peripheral portion of the elastic body extend so as to straddle the edge portion of the current collecting plate and be positioned on the 2 nd surface.

2. The electrode structure according to claim 1, wherein the entire peripheral portion of the electrode and the entire peripheral portion of the elastic member extend so as to straddle the edge portion of the current collecting plate and be positioned on the 2 nd surface.

3. The electrode structure according to claim 1 or 2, wherein a length of a portion of the electrode and the elastic body on the 2 nd surface of the current collector plate is 3mm or more and 20mm or less.

4. An electrolysis cell, comprising:

a cathode chamber,

A partition wall facing the cathode chamber, and

an anode chamber disposed opposite to the partition wall and on the opposite side of the cathode chamber,

at least one of the cathode chamber and the anode chamber includes the electrode structure body according to any one of claims 1 to 3.

5. An electrolytic cell comprising:

the electrolysis cell of claim 4, and

an ion exchange membrane disposed opposite the electrolysis unit.

Technical Field

The invention relates to an electrode structure, an electrolysis cell and an electrolysis cell.

Background

The electrolysis of an alkali metal salt refers to a method of producing an alkali metal hydroxide, hydrogen, chlorine, or the like at a high concentration by electrolyzing (hereinafter, also simply referred to as "electrolysis") an aqueous solution of an alkali metal chloride such as a saline solution. Examples of such a method include electrolysis by a mercury method and a diaphragm method, but in recent years, an ion exchange membrane method having excellent power efficiency is mainly used.

In the ion exchange membrane method, electrolysis is performed using an electrolytic cell in which a plurality of electrolytic cells each having an anode and a cathode (hereinafter, these are also collectively referred to as "electrodes") are arranged with an ion exchange membrane interposed therebetween. The electrolysis unit has a structure in which a cathode chamber to which a cathode is attached and an anode chamber to which an anode is attached are arranged back to back with a partition wall (back plate) interposed therebetween. In the electrolysis unit, an aqueous solution of an alkali metal chloride is supplied to the anode chamber, an alkali metal hydroxide is supplied to the cathode chamber, and electrolysis is performed to generate chlorine gas in the anode chamber and an alkali metal hydroxide and hydrogen gas in the cathode chamber.

In recent years, in order to further improve the electric power consumption rate, zero-pitch electrolysis, in which electrolysis is performed by bringing an ion exchange membrane into contact with a cathode, has become the mainstream. For example, patent document 1 discloses a structure of a zero-pitch electrolytic cell. Generally, a rib and an anode are disposed in an anode chamber of a zero-pitch electrolysis cell, and a rib, a current collecting plate (conductive plate), an elastic body (cushion pad), and a cathode are disposed in a cathode chamber. In the cathode chamber, a current collecting plate, an elastic body, and a cathode are arranged in this order, and the cathode is pressed by a cushion having a cushioning property, whereby the cathode can be brought into contact with the ion exchange membrane during electrolysis. Hereinafter, the structure including the collector plate, the elastic body, and the electrode is simply referred to as "electrode structure".

Patent document 2 discloses a method of using a teflon (registered trademark) needle and a method of performing welding as a conventionally known method of fixing a cathode. As a method of welding, there is a method of fixing the peripheral portion of the cathode by spot welding to the sealing surface of the cathode chamber frame using a nickel band. Specifically, the cathode is disposed on a sealing surface of a cathode chamber frame, a nickel band is further disposed thereon, and the cathode is fixed by spot welding.

Disclosure of Invention

Problems to be solved by the invention

According to the techniques described in patent documents 1 to 2, in the method of fixing the cathode to the sealing surface by spot welding using the nickel strip, there are problems such as corrosion of the sealing surface of the cathode chamber frame, chipping of the sealing surface at the time of cathode replacement, and poor working efficiency.

In the electrolytic cell, a gasket is attached to a sealing surface corresponding to the outer periphery of the electrolytic cell so that the contents do not leak out. In this case, as shown in fig. 6, since the cathode 104 and the nickel tape 106 are affixed to the sealing surface 102 of the electrolytic cell 100, there are irregularities, and the electrolyte tends to stay in this portion, and corrosion (crevice corrosion) of the sealing surface 102 may occur under some conditions. In addition, when the gasket deteriorates as the electrolysis proceeds, the gasket needs to be replaced in order to ensure the sealing performance by the gasket. In the electrolytic cell shown in fig. 6, the nickel tape 106 is peeled off together with the gasket 108 at the time of gasket replacement, and the cathode 104 may be torn. This may cause damage inside the electrolysis cell.

In addition, when the electrode is deteriorated as the electrolysis proceeds, the electrode is replaced to eliminate the reduction of the electrolysis performance. Here, when the cathode 104 is replaced, the old cathode 104 is peeled off, the sealing surface 102 of the frame 101 of the cathode chamber 110 is cleaned, and a new cathode is fixed to the sealing surface 102 by spot welding using the nickel band 106. In order to perform the fixing by welding, it is necessary to remove the oxide on the surface layer of the seal surface 102. To remove the oxide, the surface of the seal face 102 needs to be skived and the plate of the seal face 102 may be fleshed. When such an operation is repeated, the deterioration of the sealing property due to the meat shortage may become remarkable. Thus, the conventional method has a problem that the replacement of the cathode requires a lot of effort and time.

Here, in consideration of this problem, a configuration is also conceivable in which at least a part of the peripheral portion of the cathode electrode is folded over the edge portion of the current collecting plate and into the opposite side of the current collecting plate from the cathode electrode. However, when only the peripheral portion of the cathode is folded back to the opposite side of the collector plate, the cushion pad is likely to be broken with welding or replacement of the cushion pad, and as a result, damage may occur inside the electrolytic cell, such as damage to the ion exchange membrane.

As described above, in the conventional technology, there is still room for improvement in preventing damage to the inside of the electrolytic cell and preventing crevice corrosion of the sealing surface, which are caused by replacement of parts such as electrodes. The present invention has been made to solve the above problems, and an object thereof is to provide an electrode structure capable of reducing corrosion and damage inside an electrolysis cell, and an electrolysis cell using the electrode structure.

Means for solving the problems

The present inventors have conducted intensive studies to solve the above problems. As a result, the present inventors have found that the above problems can be solved by forming the electrode and the edge portion of the elastic body into a predetermined shape, and have completed the present invention.

Namely, the present invention is as follows.

[1]

An electrode structure, comprising:

an electrode,

A collector plate having a 1 st surface facing the electrode and a 2 nd surface opposite to the 1 st surface, and

an elastic body having conductivity and located between the electrode and the 1 st surface of the current collecting plate,

at least a part of the peripheral portion of the electrode and at least a part of the peripheral portion of the elastic body extend so as to straddle the edge portion of the current collecting plate and be positioned on the 2 nd surface.

[2]

The electrode structure according to [1], wherein the entire peripheral portion of the electrode and the entire peripheral portion of the elastic body extend so as to straddle the edge portion of the current collecting plate and be positioned on the 2 nd surface.

[3]

The electrode structure according to [1] or [2], wherein a length of a portion of the electrode and the elastic body on the 2 nd surface of the current collecting plate is 3mm or more and 20mm or less.

[4]

An electrolysis cell, comprising:

a cathode chamber,

A partition wall facing the cathode chamber, and

an anode chamber opposed to the partition wall and located on the opposite side of the cathode chamber,

at least one of the cathode chamber and the anode chamber includes the electrode structure according to any one of [1] to [3 ].

[5]

An electrolytic cell comprising:

[4] the electrolysis cell described in (1), and

and an ion exchange membrane disposed opposite the electrolysis unit.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide an electrode structure capable of reducing corrosion and damage inside an electrolytic cell, and an electrolytic cell using the electrode structure.

Drawings

FIG. 1 is a front view schematically showing an electrolytic cell according to an embodiment of the present invention.

FIG. 2 is a front view showing an electrolytic cell according to an embodiment of the present invention.

FIG. 3 is a view showing a cross-sectional structure of the electrolysis cell shown in FIG. 2.

FIG. 4 is an enlarged sectional view showing a part of the electrolysis cell shown in FIG. 3.

FIG. 5 is a view showing a cross-sectional structure of an electrolysis cell according to another embodiment of the present invention.

FIG. 6 is a view showing a cross-sectional structure of a conventional electrolytic cell.

Description of the symbols

1 an electrolytic bath,

22 anode chamber,

32 cathode chambers,

38 cathode, a cathode,

40a current collector plate,

44a surface (1 st surface),

44b back surface (2 nd surface),

44c edge part,

42 ribs (support bodies),

44 buffer (elastomer)

Detailed Description

The following describes in detail a specific embodiment of the present invention (hereinafter, simply referred to as "the present embodiment"). The following embodiments are examples for illustrating the present invention, and the present invention is not intended to be limited to the following. The present invention can be suitably modified and implemented within the scope of the gist thereof.

In the description of the drawings, the same or corresponding elements are denoted by the same reference numerals, and redundant description thereof is omitted. In the drawings, positional relationships such as vertical, horizontal, and the like are based on positional relationships shown in the drawings unless otherwise specified, and the dimensional ratios in the drawings are not limited to the illustrated ratios. However, the drawings merely show examples of the present embodiment, and the present embodiment should not be construed as being limited to these examples.

An electrode structure according to the present embodiment includes an electrode, a current collector plate having a 1 st surface facing the electrode and a 2 nd surface opposite to the 1 st surface, and an elastic body having conductivity and located between the electrode and the 1 st surface of the current collector plate, wherein at least a part of a peripheral portion of the electrode and at least a part of a peripheral portion of the elastic body extend so as to straddle an edge of the current collector plate and be located on the 2 nd surface. As described above, in the electrode structure of the present embodiment, since both the elastic body and the electrode are folded toward the 2 nd surface side of the current collecting plate, the elastic body and the electrode can be fixed to the current collecting plate without welding, and as a result, disconnection of the elastic body which may occur in the case of welding can be prevented. In particular, since welding of the electrodes is not required, crevice corrosion of the sealing surface due to electrolyte solution staying in the vicinity of the welded portion can be effectively prevented. Therefore, the electrode structure of the present embodiment can reduce corrosion and damage inside the electrolytic cell.

In addition, the electrode structure of the present embodiment is applied to the electrolytic cell of the present embodiment. That is, the electrolytic cell of the present embodiment includes a cathode chamber, a partition wall facing the cathode chamber, and an anode chamber facing the partition wall and located on the opposite side of the cathode chamber, and at least one of the cathode chamber and the anode chamber includes the electrode structure of the present embodiment. With such a configuration, the electrolytic cell according to the present embodiment can reduce corrosion and damage inside the cell.

The electrolytic cell of the present embodiment includes the electrolytic cell of the present embodiment, and an ion exchange membrane facing the electrolytic cell. With such a configuration, the electrolytic cell of the present embodiment can prevent corrosion and damage to the inside.

Next, the structure of the electrode structure of the present embodiment will be described in detail based on the relationship with the structure of the electrolytic cell and the electrolytic cell including the electrode structure.

FIG. 1 is a front view schematically showing an electrolytic cell according to one embodiment of the present embodiment. As shown in fig. 1, an electrolytic cell 1 is a bipolar ion exchange membrane electrolytic cell, and is configured by connecting a plurality of electrolytic cells 3 in series via an ion exchange membrane 5 (see fig. 4) by a pressurizer 7. In the electrolytic cell 1, one of the electrolytic cells 3 located at both ends is connected to the anode terminal 9, and the other is connected to the cathode terminal 11.

The electrolysis in the electrolytic cell 1 is performed by separation at the ion exchange membrane 5 between the anode chamber 22 (see fig. 3) of the electrolysis cell 3 described later and the cathode chamber 32 (see fig. 3) of the adjacent electrolysis cell 3. For example, sodium ions move from the anode chamber 22 of the electrolysis cell 3 to the cathode chamber 32 of the adjacent electrolysis cell 3 through the ion exchange membrane 5, and the current in electrolysis flows in the direction of the electrolysis cells 3 connected in series.

The ion exchange membrane 5 is not particularly limited, and a known ion exchange membrane can be used. For example, in the case of producing chlorine and alkali by electrolysis of an alkali chloride or the like, a fluorine-containing ion exchange membrane is preferable in terms of excellent heat resistance, chemical resistance, and the like. Examples of the fluorine-containing ion exchange membrane include an ion exchange membrane having a function of selectively transmitting cations generated during electrolysis and containing a fluorine-containing polymer having an ion exchange group. The fluorine-containing polymer having an ion exchange group as used herein refers to a fluorine-containing polymer having an ion exchange group or an ion exchange group precursor which can form an ion exchange group by hydrolysis. Examples of the polymer include the following: the polymer contains a fluorinated hydrocarbon main chain, has a functional group convertible into an ion exchange group by hydrolysis or the like as a pendant side chain, and is capable of melt processing; and so on.

The electrolytic cell 3 will be described in detail below. Fig. 2 is a front view showing an electrolytic cell according to an embodiment of the present embodiment, as viewed from the cathode side. FIG. 3 is a view showing a cross-sectional structure of the electrolysis cell shown in FIG. 2. The rib (support) 42 is not shown in fig. 3. FIG. 4 is an enlarged sectional view showing a part of the electrolysis cell shown in FIG. 3. As shown in the drawings, the electrolytic cell 3 includes an anode section 20, a cathode section 30, and a partition wall 50 that partitions the anode section 20 and the cathode section 30 (anode chamber 22 and cathode chamber 32). Anode portion 20 is electrically connected to cathode portion 30. The electrolysis unit 3 is a zero-pole pitch electrolysis unit.

The anode section 20 has an anode chamber 22. Anode chamber 22 is defined by frame 24. A gasket 26 is provided on the upper surface of the frame 24. An anode 28 is disposed in the anode chamber 22. The anode 28 is provided on one side surface side of the electrolytic cell 3. The anode 28 is provided on one surface side of the electrolytic cell 3, and a metal electrode such as DSA having an oxide containing ruthenium or iridium as a component coated on the surface of a titanium substrate can be used.

The cathode portion 30 has a cathode chamber 32. The cathode chamber 32 is defined by a frame 34. A gasket 36 is provided on a surface (sealing surface) 34a of the upper portion of the frame 34. The cathode chamber 32 is provided with a cathode 38, a current collecting plate 40, ribs (supports) 42, and a cushion (elastic body) 44.

The cathode 38 is provided on the other side surface side of the electrolytic cell 3. The cathode 38 that can be used in the zero-pitch electrolysis cell is preferably a cathode having a small wire diameter and a small mesh number because of its high flexibility. Various known substrates can be used for such a cathode substrate. The cathode 38 may have a wire diameter of 0.1mm to 0.5mm and an opening of about 20 mesh to 80 mesh, for example.

As the cathode coating layer, a thin coating layer of a noble metal or a noble metal oxide is preferable, and further, a rare earth may be contained in addition to the noble metal. By making the coating thin, flexibility of the cathode can be sufficiently ensured, and local damage to the ion exchange membrane 5 tends to be prevented. In order to make the coating thin, a coating of a noble metal or a noble metal oxide having high activity is preferable. Therefore, the thickness of the coating layer is preferably 0.5 μm to 50 μm, and more preferably 1 μm to 10 μm.

As shown in fig. 4, a collector plate 40 is disposed along the cathode 38. The collector plate 40 is a member for improving the current collecting effect of the cathode 38. The current collector plate 40 has a pair of front surface (1 st surface) 40a and back surface (2 nd surface) 40b facing each other. In the current collector plate 40, a surface 40a is disposed to face the cathode 38.

The current collector plate 40 is electrically conductive to the buffer pad 44 and the cathode 38, and receives a load pressed from the buffer pad 44 and the cathode 38. The current collector plate 40 also has a function of passing hydrogen gas generated from the cathode 38 to the partition wall 50 side. Therefore, the current collecting plate 40 is preferably a porous metal plate, a punched porous plate, or the like. The aperture ratio of the holes provided in the current collecting plate 40 is preferably 40% or more in order to discharge hydrogen gas generated from the cathode 38 to the partition wall 50 side. As the material of the current collecting plate 40, nickel, a nickel alloy, stainless steel, iron, or the like can be used from the viewpoint of corrosion resistance, and nickel is preferable from the viewpoint of conductivity. As the current collecting plate 40, a cathode used in a finite width gap (finite gap) electrolysis cell may be directly used. The current collector plate 40 may be a cathode for a finite gap or the like formed by coating a porous metal plate with nickel oxide by plasma irradiation.

The rib 42 is positioned in the cathode chamber 32 and is disposed between the partition wall 50 and the back surface 40b side of the current collector plate 40. The ribs 42 support the fixed collector plate 40. The rib 42 is welded and fixed to the partition wall 50 and the current collecting plate 40, respectively.

The buffer pad 44 is disposed between the cathode 38 and the surface 40a side of the current collecting plate 40. In the zero-pitch electrolysis cell 3, the rigidity of the anode 28 is ensured, so that the ion exchange membrane 5 is not easily deformed even when pushed. On the other hand, in the electrolytic cell 3, by making the cathode 38 side flexible, it is possible to absorb unevenness due to tolerance in manufacturing accuracy of the electrolytic cell 3, deformation of the electrode, and the like, and to form a structure capable of securing a zero pole pitch. The cushion pad 44 is used to form a soft structure on the cathode 38 side.

The buffer pad 44 has a function of transmitting electricity to the cathode 38 and a function of passing hydrogen gas generated by the cathode 38 to the current collecting plate 40 side. The buffer pad 44 applies an appropriate and uniform pressure to the cathode 38 in contact with the ion exchange membrane 5 to such an extent that the ion exchange membrane 5 is not damaged. Thereby, the cathode 38 is in close contact with the ion-exchange membrane 5.

As the cushion 44, a conventionally known cushion can be used. The cushion pad 44 is preferably formed to have a wire diameter of 0.05mm to 0.25 mm. When the wire diameter of the cushion pad 44 is 0.05mm or more, the cushion pad can be more prevented from being crushed, and when the wire diameter of the cushion pad 44 is 0.25mm or less, the elastic force of the cushion pad 44 is likely to be in a preferable range, and the pushing pressure during electrolysis tends to be prevented from being excessively increased, so that the performance of the ion exchange membrane 5 is less likely to be affected. Further preferably, the wire diameter is 0.08mm to 0.20 mm. As the material of the cushion pad 44, nickel is used in view of conductivity and alkali resistance. For example, the cushion pad may be one obtained by corrugating a cushion pad woven from nickel wires having a wire diameter of about 0.1 mm.

The partition 50 is disposed between the anode chamber 22 and the cathode chamber 32 (the anode unit 20 and the cathode unit 30). The partition wall 50, which is also referred to as a separation plate, separates the anode chamber 22 and the cathode chamber 32. The partition wall 50 may be one known as a separator plate for electrolysis, and examples thereof include one having a nickel-containing plate welded to the cathode side and one having a titanium-containing plate welded to the anode side.

Next, the mounting structure and the mounting method of the cathode 38 will be described in detail. As shown in fig. 4, the upper end portion (a part of the peripheral portion) of the cathode 38 is folded toward the rear surface 40b of the current collecting plate 40. Specifically, the upper end of the cathode 38 is inserted into the gap S formed between the frame 34 and the edge 40c of the current collector plate 40, and is folded back toward the rear surface 40b across the edge 40c of the current collector plate 40. In the present embodiment, not only the cathode 38 but also the cushion pad 44 is similarly folded back toward the rear surface 40b of the current collecting plate 40 at its upper end (a part of the peripheral portion). That is, the upper end of the cushion pad 44 is also inserted into the gap S formed between the frame 34 and the edge 40c of the current collector plate 40, and is folded back toward the rear surface 40b across the edge 40c of the current collector plate 40. In the conventional art, the buffer pad 44 is fixed to the current collector plate 40 by partial spot welding from the viewpoint of preventing sagging to the lower end of the electrolytic cell 3 during electrolysis and from the viewpoint of conductivity, and the above-described spot welding is not required by the configuration in which the upper end portion (part of the peripheral portion) of the buffer pad 44 is folded toward the rear surface 40b of the current collector plate 40 as in the present embodiment, that is, at least part of the peripheral portion of the buffer pad 44 extends so as to straddle the edge portion of the current collector plate 40 and lie on the rear surface 40 b. That is, not only the workability of component replacement can be improved, but also breakage of the cushion pad which may occur along with the replacement of the cushion pad can be prevented, and as a result, damage to the inside of the electrolytic cell such as damage to the ion exchange membrane can be effectively prevented.

The gap S formed between the frame 34 and the edge 40c of the current collector plate 40 is preferably 3mm to 10 mm. More preferably 4mm to 7 mm. When the gap S is 3mm or more, the cathode 38 and the buffer pad 44 tend to enter the gap more easily. When the gap S is 10mm or less, the ion-exchange membrane 5 can be effectively prevented from falling into the gap due to the contraction of the ion-exchange membrane 5, and as a result, damage to the ion-exchange membrane 5 tends to be more effectively prevented.

In order to realize the above structure, it is preferable to cut the cathode 38 to be slightly larger than the electrified portion of the electrolytic cell 3. Hereinafter, the dimension of the portion of the collector plate 40 where the cathode 38 is folded back to the back surface 40b (the portion longer than the current-carrying portion), that is, the dimension of the portion of the cathode 38 and the buffer pad 44 on the back surface 40b of the collector plate 40 is referred to as a folded-back length L. The folding length L is preferably 3mm to 20 mm. More preferably 5mm to 15 mm. When the folded length L is 20mm or less, the cathode 38 and the buffer pad 44 at the folded portion tend to be sufficiently fixed to the current collecting plate 40. When the folded length L is 3mm or more, the cathode 38 and the buffer pad 44 tend not to easily fall off the current collecting plate 40. From the same viewpoint as above, the folding length L is more preferably 10mm to 15 mm. Note that the folding length L may be specifically set to the shortest distance from the edge portion 40c to the terminal end portions of the cathode 38 and the buffer pad 44.

In fig. 4, the upper portions of the cathode 38 and the buffer pad 44 are shown, but the lower ends of the cathode 38 and the buffer pad 44 may be folded toward the rear surface 40b of the current collecting plate 40. That is, both end portions (the entire peripheral portions) of the cathode 38 and the buffer pad 44 may be folded back toward the back surface 40b of the current collecting plate 40. In this way, by folding the upper ends of the cathode 38 and the buffer pad 44 toward the rear surface 40b of the collector plate 40, the cathode 38 and the buffer pad 44 can be fixed to the collector plate 40. Moreover, by folding the lower ends of cathode 38 and buffer pad 44 toward the rear surface 40b of collector plate 40, cathode 38 and buffer pad 44 can be more firmly fixed to collector plate 40, and sagging of buffer pad 44 can be effectively prevented. It is further preferable that the entire outer peripheral portions of cathode 38 and buffer pad 44 be folded toward the rear surface 40b of collector plate 40, whereby cathode 38 and buffer pad 44 can be further firmly fixed to collector plate 40.

When the cathode 38 and the buffer pad 44 are attached to the current collecting plate 40, the cathode 38 is preferably cut at a corner (corner portion). The cathode 38 can be inserted at the corner by cutting the corner. A diagonal cut (a linear cut extending from the corner in the in-plane direction of the cathode) may be cut at the corner and inserted, but when the cut is performed in this manner, the cathode 38 tends to be broken with this position as a starting point, and therefore, as described above, the corner is preferably cut.

Various known jigs can be used to fold the cathode 38 and the buffer pad 44 toward the back surface 40b of the current collector plate 40. Specifically, the cathode 38 and the buffer pad 44 may be folded back and fixed to the back surface 40b side of the current collecting plate 40 by pressing the respective ends of the cathode 38 and the buffer pad 44 into the electrolysis cell 3 along the edge of the current collecting plate 40 with a spatula or a rotating roller. The jig for folding the cathode 38 and the buffer pad 44 is preferably a rotating roller in view of workability. The thickness of the blade of the rotating roll is preferably 0.2mm or more. When the thickness is 0.2mm or more, sufficient rigidity can be secured, and the cathode 38 and the buffer pad 44 tend to be inserted more easily. Further, if the thickness is larger than the gap S between the current collecting plate 40 and the frame 34 (the sealing surface 34a of the gasket 36), the rotating roller itself cannot enter, and it is difficult to insert the cathode 38 and the buffer pad 44, and therefore the thickness is more preferably in the range of 0.2mm to 2 mm. The diameter of the rotating roll is not particularly limited, and a rotating roll having a diameter of about 100mm is generally easy to handle.

The present embodiment is not limited to the above configuration. For example, in addition to the above-described configuration, the cathode 38 may be configured to be sandwiched between the gasket 36 and the current collecting plate 40, as shown in fig. 5. With such a configuration, when the electrolysis units 3 are connected in series by the pressurizer 7, the ion exchange membrane 5 can be pressed even by the tip of the gasket 36 not in contact with the seal surface 34, and sodium hydroxide can be prevented from entering between the gasket 36 and the ion exchange membrane 5, and damage to the ion exchange membrane 5 can be suppressed.

In addition, fig. 4 and 5 show a mode in which the cathode 38 and the buffer pad 44 extend without contacting the rear surface 40b of the current collector plate 40, and even in this state, the cathode 38 and the buffer pad 44 may be fixed to the current collector plate 40, and from the viewpoint of more secure fixation, the cathode 38 and the buffer pad 44 preferably extend so as to contact the rear surface 40b of the current collector plate 40.

In the above description, the electrode structure (i.e., cathode structure) in the case where the electrode is a cathode is described, but the electrode in the present embodiment may be an anode. That is, the electrode structure of the present embodiment may be applied to an anode chamber as an anode structure. In this case, various known members can be used for the anode chamber, and various known members can be used for the anode.