Electrolytic cell and electrolytic cell unit constituting the same

Abstract

To provide an electrolytic cell in which damage to the diaphragm is suppressed by the member used for fixing the electrode.SOLUTION: An electrolytic cell composed of at least an anode, a cathode 200A, and a diaphragm 300 between those is provided. At least one electrode of the anode and the cathode is attached to the electrode base part by an interposing member 600 interposed between the electrode base part 280 on which the electrode is provided.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to electrolytic cells and electrolytic cell units. In particular, it relates to an electrolytic cell comprising at least an anode, a cathode and a diaphragm therebetween, and to the units constituting the electrolytic cell.

Background Art

[0002] Currently, electrolysis is used in various industries. An electrolytic cell is used to perform electrolysis, that is, electrolytic decomposition. Although electrolytic cells have various forms depending on their applications, they at least include an anode and a cathode. For example, a cell for electrolyzing an aqueous solution of sodium chloride can produce chlorine, hydrogen, and sodium hydroxide (so-called caustic soda), and is used for the production of raw materials that form the basis of the chemical industry. It is also used for the electrolysis of an alkaline aqueous solution used for hydrogen production.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an electrolytic cell, a diaphragm is often further provided to avoid mixing of the substances generated at the anode and the substances generated at the cathode. A process of electrolyzing an aqueous solution of sodium chloride using an ion exchange membrane as the diaphragm is also referred to as "ion exchange membrane method for electrolyzing brine". It is also used for the electrolysis of an alkaline aqueous solution used for hydrogen production.

[0005] Although there are various types of electrolytic cells used in the ion-exchange membrane method for sodium chloride electrolysis, among them, the zero-gap type has become the mainstream. In a zero-gap type electrolytic cell, the anode, diaphragm, and cathode are closely adhered to each other to reduce the distance between the electrodes and thereby reduce the resistance of the electrolytic solution, aiming to reduce power consumption. In the "zero-gap", it is conceivable to make one of the anode and cathode softer than the other to increase flexibility, while the other has relatively high rigidity. More specifically, one electrode has a soft and flexible structure that can absorb unevenness due to tolerances and deformations such as an electrode support frame, while the other electrode has a rigid structure with high rigidity and little deformation even when pressed against the diaphragm. In such a case, by providing a conductive elastic body on the back side of the flexible electrode, the pressure required for the close adhesion of the cathode, diaphragm, and anode to each other can be provided by the elastic force (i.e., reaction force) of the conductive elastic body.

[0006] The inventor of the present application noticed that there are still problems to be overcome in the conventional electrolytic cell and found the necessity to take countermeasures therefor. Specifically, the following problems were found.

[0007] In an electrolytic cell, when the diaphragm is damaged, electrolysis cannot be efficiently carried out. Damage to the diaphragm not only makes the electrolysis operation inefficient but also may cause direct contact of the electrolytic solution between the anode side and the cathode side, raising the concern of unintended undesired reactions.

[0008] In the above-mentioned "zero-gap" electrolytic cell, since the electrode is in contact with the ion-exchange membrane, the members related to the electrode are likely to affect the ion-exchange membrane. In particular, the electrodes used in such electrolytic cells are often fixed to the support by pins from above, and such pins may be in a state of directly contacting the ion-exchange membrane. That is, the members used for fixing the electrode become members that can impose a certain load on the ion-exchange membrane in the electrolytic cell, and there is a concern that the ion-exchange membrane may be damaged depending on the degree of the load.

[0009] The present invention has been made in view of such problems. That is, the main object of the present invention is to provide an electrolytic cell technology in which damage to the diaphragm is suppressed from the viewpoint of electrode immobilization.

Means for Solving the Problems

[0010] The inventor of the present application has tried to solve the above problems by dealing with them in a new direction, rather than by following the prior art. As a result, an invention of an electrolytic cell in which the above main object is achieved has been reached.

[0011] In the present invention, an electrolytic cell is at least composed of an anode, a cathode, and a diaphragm therebetween, At least one of the anode and the cathode is attached to the electrode base by an intervening member located between it and the electrode base where it is provided.

Effects of the Invention

[0012] In the electrolytic cell of the present invention, damage to the diaphragm is suppressed due to the intervening member provided between the electrode and its electrode base.

[0013] Specifically, in the electrolytic cell of the present invention, at least one of the anode and the cathode is attached and fixed to the electrode base by an intervening member between it and the electrode base. That is, where the electrode is fixed to the support member by the intervening member, such an intervening member is positioned between the electrode and the support member and cannot come into direct contact with the diaphragm. This means that the intervening member in the present invention can suppress damage to the diaphragm while fixing the electrode to the support. Therefore, in the present invention, an electrolytic cell technology that preferably suppresses undesired events caused by damage to the diaphragm can be provided.

Brief Description of the Drawings

[0014]

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Figure 18

MODE FOR CARRYING OUT THE INVENTION

[0015] Hereinafter, with reference to the drawings, an "electrolytic cell" according to an embodiment of the present invention will be described in more detail. Various elements in the drawings are merely shown schematically and exemplarily for the understanding of the present invention, and the appearance, dimensional ratios, etc. may differ from the actual objects.

[0016] In this specification, the "electrolytic cell" generally refers to a device for performing electrolysis, and specifically refers to a device having at least an anode, a cathode, and a diaphragm provided between these electrodes. Also, in this specification, the "electrolytic cell unit" corresponds to a sub-tank for constructing an electrolytic cell, and refers to a tank element that can form an electrolytic cell by being combined with each other via a diaphragm.

[0017] The directions of "up and down" and "left and right" directly or indirectly described in this specification respectively correspond to the up and down directions and left and right directions in the drawings. More specifically, in the form shown in FIG. 7, the direction along the plane direction of the electrode corresponds to the left and right direction, and the direction orthogonal to it corresponds to the up and down direction. During the operation of the electrolytic cell, the electrodes in the form shown in FIG. 7 and the like are often used in the standing orientation shown on the left side of FIGS. 3 and 6 (that is, the electrodes are often used after changing the orientation by approximately 90° from the state of FIG. 7). Therefore, the orientation of the tank and its components may differ between the usage time of the electrolytic cell (especially during the operation in a state where the units constituting the electrolytic cell are combined) and the non-usage time (especially during the non-operation before the units constituting the electrolytic cell are combined).

[0018] The various numerical ranges referred to in this specification are intended to include the numerical values of the lower and upper limits themselves. That is, for example, taking a numerical range of 1 to 10 as an example, it is interpreted as including the lower limit value of "1" and also including the upper limit value of "10".

[0019] First, the basic configuration of the electrolytic cell that is the premise of the present invention will be described, and then the features of the present invention will be explained. Note that the description of the electrolytic cell unit itself will be included in the description of the electrolytic cell.

[0020] [Basic Configuration of Electrolytic Cell] The electrolytic cell of the present invention comprises at least an anode, a cathode, and a diaphragm disposed between these electrodes. The anode and the cathode are electrodes for applying external electrical energy to the electrolyte solution. Typically, the anode is an electrode connected to the positive electrode of an external power source and is an electrode capable of causing an oxidation reaction during the operation of the electrolytic cell. On the other hand, the cathode is typically an electrode connected to the negative electrode of the external electrode and is an electrode capable of causing a reduction reaction during the operation of the electrolytic cell.

[0021] The diaphragm is typically a member that separates the anode chamber and the cathode chamber. Preferably, a diaphragm is provided to avoid mixing of the substances generated at the anode and the substances generated at the cathode. In the present invention, the diaphragm may be one conventionally used in electrolysis. For example, the diaphragm may be an ion exchange membrane. Although it is merely one example, in the electrolytic cell used in the soda industry, a cation exchange membrane may be used as the diaphragm.

[0022] The electrolytic cell may further be provided with a conductive elastic body. The conductive elastic body can contribute to the energization between the electrodes due to its "conductivity" and can also apply a pressing force to the electrodes due to its "elasticity". That is, the conductive elastic body corresponds to a conductive component capable of presenting a reaction force in the electrolytic cell, and has at least a structure capable of elastic deformation to provide such a reaction force.

[0023] An exemplary configuration of an electrolytic cell is schematically shown in FIG. 1. As shown in the figure, in the electrolytic cell, a conductive elastic body is used for an electrode assembly composed of at least an anode, a cathode, and an ion exchange membrane between these electrodes. In such an electrolytic cell, the reaction force of the conductive elastic body is utilized to press the electrode assembly composed of at least the anode, the cathode, and the ion exchange membrane between these electrodes. Specifically, the conductive elastic body is used in a state of being elastically deformed on the back side of the electrode assembly, and an elastic force (i.e., reaction force) provided by such a conductive elastic body brings a pressing force to the electrode assembly. In particular, the elastically deformed conductive elastic body acts to apply a pressing force from one electrode toward the other electrode, thereby promoting the adhesion of the electrode assembly. That is, due to the presence of the conductive elastic body, close contact is brought about between the anode, the ion exchange membrane, and the cathode, and the electrolytic cell can function preferably as a so-called "zero gap" type.

[0024] The conductive elastic body used in the electrolytic cell may have any form as long as an elastic repulsive force is generated. By way of example, the conductive elastic body may have various forms such as an elastic cushion, an elastic mat (for example, a member made of a metal coil body, a non-woven fabric made of metal, a knitted or woven fabric made of metal wire, etc.), and a leaf spring. Although it is only one specific example, the conductive elastic body 400 may be provided with a wave-shaped curved elastic portion 450 as shown in FIG. 2. The conductive elastic body is used in a state of being elastically deformed so as to exhibit spring characteristics in the electrolytic cell. More specifically, for example, the conductive elastic body is provided in the electrolytic cell in a state of being deformed so that the wave-shaped curve of the elastic portion is reduced. In the conductive elastic body thus deformed, a stress acts to try to return to its original shape, so that a reaction force is exhibited as spring characteristics. In a large-sized electrolytic cell, the conductive elastic body is often provided as a plurality of conductive elastic bodies rather than being used singly.

[0025] In an electrolytic cell, the electrodes may be composed of, for example, a conductive substrate having liquid permeability. In this regard, it is preferable that at least one of the anode and the cathode comprises a conductive porous substrate. In other words, at least one of the anode and the cathode may be a mesh opening electrode having mesh openings. It should be noted that these are merely examples, and the electrodes may be composed of, for example, expanded metal, wire mesh (plain weave mesh, twill weave mesh), or perforated metal.

[0026] In a preferred embodiment, both the anode and the cathode may comprise a conductive porous substrate. For example, both electrodes may be composed of expanded metal or plain weave mesh, or one electrode may be composed of expanded metal and the other electrode may be composed of plain weave mesh. That is, both the anode and the cathode may have expanded mesh or plain weave mesh, or one of the anode and the electrode may have expanded mesh and the other may have plain weave mesh. From the perspective of exhibiting corrosion resistance, etc., each of the anode and the cathode may comprise at least one selected from the group consisting of titanium, nickel, stainless steel, tantalum, zirconium, niobium, etc. Also, a suitable catalyst may be supported on each of such anodes and cathodes. The aperture ratio of the conductive porous substrate is not particularly limited, but may be about 20% to 90%, for example, 30% to 80%, 40% to 75%, or 50% to 75%.

[0027] The electrolytic cell is preferably composed of a plurality of electrolytic cell units. Each electrolytic cell unit comprises at least an electrode and a support frame for supporting the electrode. The support frame preferably supports the electrode to assist in the planar arrangement of the electrode and forms the frame portion of the unit. Therefore, the electrode unit has a form in which the electrode is arranged on its side surface, and the electrode is arranged so as to occupy most of the unit side surface. In this way, an electrolytic cell may be constituted by combining each electrode cell unit provided with an electrode on its side surface via a diaphragm.

[0028] The electrolytic cell is preferably a zero-gap type. Thus, in a preferred embodiment, the electrolytic cell has features suitable for such a zero-gap type. As one of such features, the anode and the cathode are characterized in terms of the so-called "hardness" and "softness" such as the rigidity and flexibility of the electrode material. Specifically, it is preferable that one of the anode and the cathode is relatively flexible with respect to the other, and conversely, the other is relatively rigid with respect to the one. Thereby, the relatively flexible electrode can be bent by receiving the reaction force of the conductive elastic body, while the relatively rigid electrode can receive the bending thereof through the ion exchange membrane. When the anode and the cathode are different from each other in such a view, the adhesion between the anode, the ion exchange membrane, and the cathode becomes more preferable, and the electrolytic cell can function more preferably as a "zero-gap type". This is particularly applicable when the electrolytic cell is large-sized. That is, it is particularly applicable when the main surface of the electrode that requires pressing for zero gap is large, as represented by the case of zero-gap type sodium chloride electrolysis.

[0029] To obtain a larger amount of the desired electrolytic product, a larger electrolytic cell is used, and the main surfaces of the electrodes (especially the main surfaces where the anode and the cathode face each other) also increase accordingly. A large zero-gap type electrolytic cell is preferably composed of a plurality of electrolytic cell units. In each of these electrolytic cell units, large electrode surfaces are provided on both opposing side surfaces. By way of example only, a so-called "bipolar type" electrolytic cell will be described with reference to FIG. 3. On one of the opposing side surfaces of the electrolytic cell unit 100, a cathode 200A (for example, a cathode surface made of expanded metal) is provided, while on the other of the two side surfaces, an anode 200B (for example, an anode surface made of expanded metal) is provided. In the electrolytic cell, a plurality of such electrolytic cell units are connected in series so that they overlap each other via an ion exchange membrane 300 (especially a cation exchange membrane). In particular, in adjacent electrolytic cell units, the cathode surface of one electrolytic cell unit 100' and the anode surface of the other electrolytic cell unit 100'' are overlapped so as to face each other. In this way, the electrolytic cell is constituted by combining a plurality of electrolytic cell units via an ion exchange membrane. Note that the electrolytic cell composed of a plurality of electrolytic cell units is not limited to the "bipolar type", and may also be of the "monopolar type". That is, the electrolytic cell units constituting the electrolytic cell are not limited to bipolar type electrolytic cell units provided with an anode part and a cathode part on both opposing side surfaces, but may also be "monopolar type" electrolytic cell units provided with only an anode part and only a cathode part on both opposing side surfaces. In such a case, the electrolytic cell can be constituted by combining an electrolytic cell unit provided with only an anode part and an electrolytic cell unit provided with only a cathode part so that they are alternately arranged via an ion exchange membrane.

[0030] An electrolytic cell composed of electrolytic cell units is preferable because the electrode surface size is relatively large and a desired electrolytic reaction is carried out through the large electrode surface, but it becomes difficult to maintain the flatness of the electrode surface. Specifically, the larger the size of the electrode surface, the more the influence of deflection caused by its own weight and the like becomes impossible to ignore. In addition, the attachment to the electrode support also has an impact, and it is difficult for such an electrode surface to achieve a completely flat surface. For example, in the electrolytic cell unit 100 (100’, 100’’) exemplified in FIG. 3, the surface sizes of the anode surface and the cathode surface are on the order of m rather than on the order of several cm. Even when the electrode is made rigid to obtain a more suitable flat surface, such a large electrode surface has a flatness of about ±0.5 mm to 1.0 mm due to the above reasons and the like, and it is difficult to become a completely flat surface (that is, a flatness of 0 mm). In other words, in a large electrolytic cell, a rigid electrode surface tends to be a surface with local irregularities when viewed microscopically even though it appears flat macroscopically.

[0031] When electrodes that are not completely flat surfaces are brought into close contact with each other through an ion exchange membrane, the unevenness may impair the uniformity of the current distribution. Therefore, in a preferred electrolytic cell, for a rigid electrode, the paired electrode is a flexible electrode. As a result, even if the electrodes are strongly adhered to each other through the ion exchange membrane, the flexible electrode will bend so as to follow the unevenness of the rigid electrode surface, and as a result, non-uniformity of the current distribution and the like can be more preferably prevented. Although this is merely an example, the anode may be composed of a relatively hard and rigid expanded metal, while the cathode may be composed of a relatively soft and flexible expanded metal. And a conductive elastic body may be provided on the back side of the flexible expanded metal of the cathode that is combined with the rigid expanded metal of the anode through the ion exchange membrane. In such a case, due to the reaction force of the conductive elastic body, the flexible expanded metal of the cathode is pressed toward the rigid expanded metal of the anode, and at that time, the flexible expanded metal of the cathode can be locally displaced according to the flatness of the main surface of the rigid expanded metal of the anode. Therefore, even when the electrolytic cell units are fixed so as to be strongly tightened and the reaction force of the conductive elastic body acts greatly, the anode, the ion exchange membrane, and the cathode are preferably adhered to each other, and unfavorable phenomena such as non-uniformity of the current distribution are hardly caused.

[0032] Although not particularly limited, the relatively hard and rigid expanded metal, due to its "relative rigidity", may preferably have a thickness of about 0.2 to 2.0 mm, and the width (pitch) of the strand 210 forming pores or openings (the portion indicated by "W" in Fig. 4) may preferably be about 0.2 to 2.0 mm. Similarly, although not particularly limited, the flexible expanded metal, due to its "relative flexibility", may, for example, preferably have a thickness of about 0.1 to 1.0 mm, more preferably about 0.1 to 0.5 mm, and the width (pitch) of the strand forming pores or openings (the portion indicated by "W" in Fig. 4) may preferably be about 0.1 to 2.0 mm, more preferably about 0.1 to 1.5 mm. When using a wire mesh or punching metal as the flexible electrode, due to its "relative flexibility", for example, the thickness may preferably be about 0.1 to 1.0 mm, more preferably about 0.1 to 0.5 mm. In the case of a wire mesh, the wire diameter φ, which means the approximate diameter of the metal fibers constituting the wire mesh, may preferably be about 0.05 to 1.0 mm, more preferably about 0.1 to 0.5 mm. In the case of punching metal, the non-opening length L between adjacent openings may be about 0.1 to 2.0 mm, more preferably about 0.1 to 1.5 mm.

[0033] For a further understanding of the electrolytic cell, FIG. 5 is shown. FIG. 5 corresponds to a cross-sectional view of an electrolytic cell in an exemplary embodiment as seen from the vertical direction. That is, FIG. 5 corresponds to a cross-sectional view when the cell shown in FIG. 3 (particularly the combination of electrolytic cell units) is cut horizontally. In the embodiment shown in such FIG. 5, with respect to the arrangement in which the flexible cathode 200A of expanded metal, the diaphragm 300, and the rigid anode 200B of expanded metal are stacked in that order, the conductive elastic body 400 is provided on the back side of the cathode 200A (that is, the side opposite to the side where the diaphragm 300 is installed). The conductive elastic body 400 is deformed and provided so as to be constricted between the flexible cathode 200A of expanded metal and the cathode base 280 (more specifically, such constriction is made and the deformation of the conductive elastic body is brought about by clamping a plurality of connected electrolytic cell units together). As a result, the elastic force of the conductive elastic body 400 is directly applied to the flexible cathode 200A of expanded metal that is in direct contact with the elastic portion of the conductive elastic body 400. As a result, the flexible cathode 200A of expanded metal is biased so as to be pressed toward the rigid anode 200B of expanded metal, resulting in closer contact between the flexible cathode 200A, the diaphragm 300, and the rigid anode 200B. Note that the rigid anode itself, which is an electrode not in direct contact with the conductive elastic body, is fixed to the electrode support of the electrolytic cell unit or the like so as not to move, and thus acts to receive the elastic force of the conductive elastic body and contributes to the closer contact.

[0034] Although it is only one specific example, the electrolytic cell unit provided with the rigid anode is at least composed of the rigid anode and a support frame that supports it. On the other hand, the electrolytic cell unit provided with the flexible cathode is at least composed of a conductive electrode base, a support frame that supports it, a conductive elastic body provided on the electrode base, and a flexible cathode disposed on the conductive elastic body. The electrode base may have higher rigidity than the flexible cathode so as to support at least the flexible cathode.

[0035] [Features of the Present Invention] The present invention has features related to the electrodes used in the above-described electrolytic cell, and in particular, has features in terms of the installation form of the electrodes. Specifically, at least one of the anode and the cathode is attached to the electrode base by an intervening member between the electrode and the electrode base where it is provided.

[0036] Exemplary forms of the electrodes according to the present invention are schematically shown in FIGS. 6 and 7. FIGS. 6 and 7 show a partial cross-section of the electrolytic cell unit and show the form at the time before the electrolytic cell units are combined (the diaphragm is shown together with the electrolytic cell unit for understanding the invention). That is, FIGS. 6 and 7 show the state before the spring characteristics are exhibited in the conductive elastic body by tightening the combined electrolytic cell units, and before the diaphragm and the electrode are in close contact with each other. As can be seen from the illustrated form, an intervening member 600 is provided between the electrode 200 used in the electrolytic cell and the electrode base 280 where the electrode 200 is attached to the electrode base 280.

[0037] The intervening member 600 joins the electrode 200 and the electrode base 280 to each other. The intervening member 600 used for attaching the electrode 200 to the electrode base 280 is, as its name implies, provided between the electrode 200 and the electrode base 280, and preferably does not include a portion positioned in the upper region of the electrode 200. Therefore, the intervening member 600 is a member that can suppress the risk of causing diaphragm damage while being used for attaching the electrode in the electrolytic cell.

[0038] As shown in FIG. 18, the pin 800 that was previously used for electrode immobilization is used from above the electrode 200 so as to press the electrode 200 from above. Therefore, the conventional immobilization pin 800 has a portion (for example, the flange portion 850 as shown in the drawing) positioned in the upper region of the electrode 200 and is in a state where it can directly contact the ion exchange membrane. Such a pin can be said to be a member that can impose a significant load on the ion exchange membrane in the electrolytic cell, and there is a concern that the ion exchange membrane may be damaged depending on the degree of the load. On the other hand, the intervening member 600 in the present invention does not have a portion positioned in the upper region of the electrode 200 (that is, a portion positioned above the electrode or on the diaphragm side), and avoids direct contact with the diaphragm 300 (see FIGS. 6 and 7). Therefore, in the present invention, damage to the diaphragm by the intervening member 600 can be preferably prevented.

[0039] As used herein, the term "intervening member" broadly refers to an additional member provided between an electrode and its support member in an electrolytic cell or an electrolytic cell unit. Narrowly, in the cross-sectional view illustrated in the present application, it is a member positioned in the region between the electrode and the electrode base (a conductive electrode base on which the electrode is provided or attached and which can function as a support for the electrode) and at least partially in contact with both of them. Preferably, the intervening member is positioned only between the electrode and its electrode base.

[0040] Also, as used herein, "intervening between the electrode base" means being positioned in the region between the electrode used in the electrolytic cell or electrolytic cell unit and its electrode base. In terms of a certain cross-section, it can be said that the intervening member is positioned between the electrode and the electrode base when viewed macroscopically. Therefore, when the electrode end is bent as described later (FIGS. 9 to 12), although the intervening member is clamped by the electrode end, the intervening member is positioned between the electrode and the electrode base when viewed macroscopically.

[0041] As can be seen from FIGS. 6 and 7, the intervening member 600 is disposed in an upper region than the electrode base 280 on which the electrode 200 is supported. Further, the intervening member 600 is preferably provided so as to be disposed on the electrode base 280 and at least partially overlap with the electrode 200 (for example, its end portion 250).

[0042] Furthermore, it can be said that the intervening member 600 is disposed on the distal side of the electrode 200 with respect to the diaphragm 300. That is, when viewed from the diaphragm 300, the intervening member 600 is farther away than the electrode 200. This means that even when the electrolytic cell units are combined and the electrode 200 and the diaphragm 300 are in close contact with each other, the intervening member 600 is not positioned between the electrode and the diaphragm, and direct contact between the intervening member 600 and the diaphragm 300 is absent or reduced. Therefore, in the present invention, even under the condition that the electrode 200 and the diaphragm 300 are in close contact with each other, damage to the diaphragm caused by the intervening member 600 contributing to electrode fixation is preferably prevented.

[0043] The intervening member 6 could be of any type as long as it is located between the electrode and its electrode base and contributes to the attachment and fixation of the electrode. For example, the intervening member may have conductivity. The intervening member having conductivity can contribute to the energization between the electrodes. Also, the intervening member may have a form such as a thin plate shape or a wire shape. That is, the member located between the electrode and its electrode base and responsible for the attachment and fixation of the electrode may be a thin plate member or a wire member. The thin plate member may be thinner than the thickness of the electrode (for example, a mesh opening electrode) because it is a "thin plate". The thin plate member may have a foil form, for example. Similarly, the thickness dimension (cross-sectional dimension) of the wire member may also be smaller than the thickness dimension of the electrode (for example, a mesh opening electrode). However, the present invention is not necessarily limited to such dimensional relationships, and the thickness dimension of the thin plate member or the thickness dimension of the wire member may be larger than the thickness dimension of the electrode (for example, a mesh opening electrode).

[0044] In the exemplary embodiment shown in FIG. 7, a thin plate-like member 640 is used as the intervening member for attaching the electrode 200. In the exemplary embodiment shown in FIG. 8, a wire-like member 660 is used as the intervening member for attaching the electrode 200. As can be seen from such exemplary embodiments, the intervening member 600 is positioned between the electrode 200 and the electrode base 280 in the electrolytic cell and electrolytic cell unit, and contributes to the fixation of the electrode 200.

[0045] An intervening member such as a thin plate-like member or a wire-like member contributes to the attachment and fixation of the electrode. Preferably, the electrode and the electrode base are joined to each other by such an intervening member. That is, the intervening member between the electrode 200 and the electrode base 280 acts as a joining material therebetween, and the electrode 200 is attached to the electrode base 280.

[0046] If such an intervening member contributes to "joining", there is no particular limitation on its material. For example, the intervening member may contain at least a metal material. The metal material is particularly suitable when the joining by the intervening member becomes welding (the mode of "welding" will be described later). In the case of a metal material, not only the strength required for the intervening member is provided, but also the corrosion resistance of the intervening member is easily provided, which is preferable. For example, titanium, nickel, stainless steel, etc. are preferable in terms of the strength and corrosion resistance required for the intervening member.

[0047] In the present invention, the intervening member is not necessarily composed only of a metallic material. The intervening member may be a member containing a resin material. An intervening member containing a resin material is particularly likely to exhibit adhesiveness. Such an intervening member may be used as an adhesive for joining electrodes and electrode bases to each other. In the case of a resin material, appropriate flexibility is imparted to the intervening member, and even if the electrode portion provided with the intervening member comes into contact with the separator, the influence of the electrode portion can be reduced. Moreover, an intervening member made of a resin material can be provided by subjecting a resin precursor having variability or fluidity to curing after being provided. Therefore, it is easy to provide an intervening member in an arbitrary form and at an arbitrary location. As a specific resin material, for example, a fluororesin is preferable because it can exhibit suitable corrosion resistance. The fluororesin may be at least one selected from the group consisting of PTFE (polytetrafluoroethylene resin), PFA (tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin), PVDF (vinylidene fluoride resin), ETFE (tetrafluoroethylene-ethylene copolymer resin), FEP (tetrafluoroethylene-hexafluoropropylene copolymer resin), and PCTFE (chlorotrifluoroethylene resin). Note that the resin material is not necessarily limited to a fluororesin, and may be at least one selected from the group consisting of epoxy resin, UV epoxy resin, unsaturated polyester resin, polyamide resin, epoxy resin, phenol resin, vinyl chloride resin, vinyl acetate resin, urethane resin, ABS resin, AS resin, AAS resin, ethylene-vinyl chloride copolymer resin, butyral resin, ethylene-vinyl acetate copolymer resin, polyimide resin, polyacetal resin, polyethylene resin, polycarbonate resin, styrene resin, styrene maleic acid resin, polysulfone resin, melamine resin, urea resin, xylene resin, coumarone resin, ketone resin, maleic acid resin, polyvinyl alcohol, polyvinyl ether, polyterpene resin, terpene phenol resin, and acrylic resin.

[0048] Various joining forms by an intervening member can be considered. For example, welding may be performed for the mutual joining of the electrode and the electrode base. That is, the intervening member serves as a welding member, and thus the electrode base and the electrode may be joined to each other. When a thin plate member or a wire member is used, the electrode base and the electrode may be welded to each other through such a thin plate member or wire member. Thereby, the electrode can be fixed to the electrode base with a more suitable fixing force. Since the intervening member such as a thin plate member or a wire member may be locally provided at the electrode, it can be said that spot welding may be performed through such a member. When "welding" is assumed, it is preferable that the intervening member is made of a fusible material that can be melted once by a welding gun, a light beam, or the like. Accordingly, the intervening member such as a thin plate member and a wire member may be provided as, for example, a metal member. Considering points such as corrosion resistance, the metal of such a metal member is preferably at least one selected from the group consisting of titanium, nickel, stainless steel, tantalum, zirconium, niobium, and the like. Such a thin plate member is likely to stabilize the current during welding. The thin plate member may be, for example, a metal foil, and for example, it may be a nickel foil. Similarly, the wire member may be, for example, a metal wire, and for example, it may be a nickel wire. The nickel foil or the nickel wire is particularly suitable in terms of both corrosion resistance and welding characteristics.

[0049] Whether it is a bonding mode or a welding mode, in the present invention, it is preferable that the electrode and the electrode base are joined to each other through an intervening member. Therefore, in the present invention, the intervening member can also be referred to as a "joining member" or the like.

[0050] In a preferred embodiment, an intervening member is provided in at least the end region of the electrode. That is, for example, as shown in FIGS. 6 and 7, in the electrode end 250 which is a region outside the region where the conductive elastic body 400 is disposed, an intervening member 600 may be provided as a different member from various elements of the electrode (the electrode and the electrode base supporting it) and the conductive elastic body. When an intervening member is provided at the end of the electrode, an effect of suppressing diaphragm damage can be achieved from the viewpoint of the "end edge" of the electrode. This is because the provision of an intervening member between the electrode and the electrode base in the end region leads to the fixation and localization of the electrode edge, making it easier to reduce the adverse effect of the electrode edge on the diaphragm. In terms of the arrangement captured in plan view, a thin plate-like member or a wire-like member may be provided for at least one (i.e., at least one side) of the sides forming the outer peripheral edge of the electrode. In such a case, it is preferable that a long thin plate-like member or a wire-like member is provided along such a side.

[0051] The electrodes of the electrolytic cell and the electrolytic cell unit are particularly likely to have sharpened end edges (i.e., the edges forming the outermost edge of the electrode). This is because the electrodes are often porous or open. That is, in a porous or open electrode, the end edge of the electrode is likely to become sharp. As shown in FIG. 17, the electrode 200 used in the electrolytic cell may have a sharp edge like "standing on end" due to a plurality of wire materials forming pores or openings. In other words, it can be said that an electrode made of a conductive porous substrate is likely to have a sharp end edge due to the wire materials constituting the pores. Although a sharp end edge is likely to damage the diaphragm, when an "intervening member" is provided at the electrode end to fix and localize the end edge, the diaphragm damage caused by such a sharp edge can be suppressed.

[0052] That is, when the intervening member is provided in the end region of the electrode, there is no portion of the electrode attachment member positioned above the electrode, direct contact with the separator is avoided, and by such attachment, the edge is fixed and positioned, and unfavorable events such as the sharp portion of the edge contacting the separator, for example, piercing it, are suppressed. Therefore, such an aspect leads to more suitable suppression of separator damage during the operation of the electrolytic cell. Note that the "end region of the electrode" as used in this specification generally refers to the peripheral region of the electrode, and specifically refers to the peripheral region from the electrode edge (the outermost edge of the electrode) to the inside, for example, about 1 mm to 3 cm (in some cases, about 1 mm to 5 mm).

[0053] In the aspects shown in FIGS. 7 and 8, the intervening member 600 is provided at the electrode end 250 without being particularly bent, but the intervening member 600 may be provided at the bent electrode end 250 as shown in FIGS. 9 and 10.

[0054] In FIG. 9, a thin plate-like member 640 is applied as the intervening member to the largely bent electrode end 250, and in FIG. 10, a wire-like member 660 is applied as the intervening member to the electrode end 250 bent in such a manner. As shown in the figure, the intervening member 640 may be positioned between the electrode 200 and the electrode base 280 in such a form that the electrode end 250 is bent and the intervening member 600 is sandwiched between the bent end 250. When the end is bent, it becomes easier to arrange the edge 255 of the electrode 200 so as not to touch the separator 300. That is, when the intervening member 600 is used in the forms shown in FIGS. 9 and 10, separator damage can be more effectively suppressed. Further, the intervening member 600 is arranged on the distal side of the separator 300 with respect to the electrode 200 (particularly the electrode portion other than the edge 255 and its vicinity) in the same manner as in the aspects of FIGS. 7 and 8, so there is no direct contact between the intervening member 600 and the separator 300, and separator damage can also be suppressed in this regard.

[0055] As can be particularly understood from the form shown in FIG. 9, the thin plate-like member 640 provided as an intervening member may have a portion positioned above the end edge 255 of the electrode. More specifically, the thin plate-like member 640 may be bent and sandwiched between the electrode ends 250, but may extend beyond the end edge 255 of the electrode. Thereby, the end edge of the electrode is covered with the thin plate-like member, and the effect of suppressing diaphragm damage is likely to be enhanced. As shown in FIG. 9, the edge 255 may be at least partially wrapped by the intervening member 600. Also, although the wire-like member does not provide as wide a surface as the thin plate-like member and is not easily provided as a member for covering the end edge, due to its narrow shape, it can act relatively effectively on the products (for example, gaseous products) generated at the electrodes during the operation of the electrolytic cell. Specifically, in the wire-like member 660 (see FIG. 10), due to its thin shape, it is difficult to inhibit the flow of the generated gas generated at the electrodes, and it is easy to avoid the inconvenient retention of such gas. When using a wire-like member as the intervening member, only one wire-like member may be used, or a plurality of wire-like members may be used.

[0056] The bent portion of the end 250 of the electrode may have a contour shape as shown in FIGS. 9 and 10. That is, the bent portion 257 of the electrode end 250 may have a curved cross-sectional shape. In the electrode end having such a form, the adverse effects that can be given to the diaphragm due to the bent portion can be reduced. That is, since the cross-sectional contour of the bent portion is not angular and is relatively smooth, even if the bent portion accidentally contacts the diaphragm in the electrolytic cell, it is difficult to damage the diaphragm. Also, if the electrode breaks or is cut due to the bent portion of the electrode end, it is easy to damage the diaphragm. However, in the bent portion having a curved shape according to the present invention, even if a stress that causes breakage or cutting occurs, stress concentration is difficult to occur and breakage or cutting of the electrode is suppressed.

[0057] As can be seen from the embodiments shown in FIGS. 9 and 10, it is preferable that the electrode end 250 is bent on the side opposite to the side where the separator 300 is located. This is because the bending direction of the electrode end is more distal with respect to the separator. That is, by bending away from the separator, the electrode edge can be more reliably separated from the separator, and the effect of suppressing separator damage can be enhanced. Here, "the end is bent on the side opposite to the side where the separator is located" means that the electrode is bent in a direction in which the end edge of the electrode is further away from the separator.

[0058] Similarly, as can be seen from the embodiments shown in FIGS. 9 and 10, it is preferable that the electrode 200 is bent at its end without straddling the electrode base 280 on which it is provided. For example, in a configuration where a relatively flexible electrode 200A (for example, an electrode 200A made of a conductive porous substrate) is disposed on the electrode base 280 together with a conductive elastic body, the electrode end 250 does not extend across the electrode base 280. As can be seen from the illustrated form, it can be said that the bent portion 250' at the electrode end 250 is disposed on the electrode base 280 together with the intervening member 600. Note that the electrode base 280 is a conductive member and generally has higher rigidity than the electrode 200A and can be used to support the flexible electrode 200A and the intervening member 600. Also, in a certain preferred embodiment, when the intervening member is sandwiched by the electrode with the electrode end bent without straddling the electrode base, a stress that promotes the adhesion of the electrode to the separator is likely to occur at the electrode end.

[0059] When the electrode end 250 is bent, as shown in FIGS. 11 and 12, it may be bent in a meandering manner. More specifically, an intervening member 600 such as a thin plate member 640 or a wire member 660 may be disposed in a form sandwiched by the end 250 bent in a meandering shape.

[0060] By making the bending of the electrode end portion serpentine, it becomes easier to position the electrode edge more distally from the separator, and damage to the separator can be more suitably suppressed. Also, by making the bending serpentine, an appropriate stress can be applied to the electrode. Preferably, by making the bending serpentine, a stress that promotes adhesion of the electrode to the separator can be generated at the electrode end portion, which can contribute to improved adhesion between the anode, the ion exchange membrane, and the cathode.

[0061] As described above, when the electrode 200 of the electrolytic cell / electrolytic cell unit is porous or open, in the past, the pins used for electrode fixation were in a state where they could contact the separator, but in the present invention, the intervening member 600 is positioned substantially only between the electrode 200 and the electrode base 280, so that the member for fixing the electrode does not contact the separator or such contact is reduced. Also, when the electrode 200 of the electrolytic cell / electrolytic cell unit is porous or open, the edge of the electrode end portion tends to become sharp (see Fig. 17), but if an intervening member is used in the region of the electrode end portion according to the present invention, the influence of the sharp edge can also be suppressed. In other words, when the electrode used in the electrode cell / electrolytic cell unit of the present invention is made of a conductive porous base material, it can be said that the effects of the present invention are more likely to be manifested. More specifically, at least one of the anode and the cathode is a mesh opening electrode made of, for example, expanded metal, wire mesh (plain weave mesh, twill weave mesh), or perforated metal, and when such a mesh opening electrode is used together with an "intervening member", the effect of suppressing separator damage is more likely to be manifested.

[0062] Similarly, the effects of the present invention are also likely to be manifested when the diaphragm used in the electrolytic cell is an ion exchange membrane. An ion exchange membrane used in an electrolytic cell is, for example, relatively thin, about 0.1 to 0.5 mm, and is often made of a relatively soft material compared to the electrodes (for example, as a cation exchange membrane used in an electrolytic cell, a flexible thin film made of a fluororesin film having a cation exchange group may be used). Therefore, when an ion exchange membrane is used in the electrolytic cell, damage to the ion exchange membrane is usually likely to be caused not only by the pins used for fixing the electrodes of the electrolytic cell but also by the presence of the electrodes. Thus, when at least one of the anode and cathode electrodes is a metal conductive porous substrate and the diaphragm directly facing such an electrode is an ion exchange membrane, the effect of suppressing diaphragm damage is likely to be manifested.

[0063] In the present invention, the intervening member can be installed by any method. For example, before the electrolytic cell units are combined, an intervening member having a desired shape may be provided to the electrodes in advance. Thereafter, heat treatment may be performed to join them through the intervening member. For example, in the case of welding and joining the electrode and the electrode base by the intervening member, after positioning the intervening member between the electrode and the electrode base, heat treatment may be performed with a welding gun, a light beam, or the like.

[0064] Also, when the intervening member is used together with the bending of the end of the electrode, such bending of the electrode end may be performed by any method. For example, bending can be applied to the electrode end by using appropriate pressing means and / or appropriate gripping means (means for gripping the electrode end, etc.). Typically, bending can be performed by applying an external force to the electrode end. In this case, it is preferable to apply an external force and bend it before the electrolytic cell units are combined.

[0065] As described above, the present invention is characterized in that an intervening member is provided between the electrode and the electrode base so that the electrode is attached to the electrode base. Such a present invention can be embodied in various aspects. This will be described below.

[0066] (Combination mode of sheet-like member and electrode end bending) In this mode, a sheet-like member is provided and the electrode end is bent. In the exemplary modes shown in FIGS. 13 and 14, a sheet-like member 640 is used for electrode attachment as the intervening member 600, and the electrode end 250 is bent with respect to the sheet-like member 640.

[0067] In the mode of FIG. 13, the sheet-like member 640 is disposed on the electrode base 280, and the bent electrode end 250 is provided on the sheet-like member 640. The electrode end 250 is bent such that the end edge 255 of the electrode is located on the upper surface of the sheet-like member 640 disposed on the electrode base 280. As shown, the sheet-like member 640 may be directly provided on the electrode base 280, and the end edge 255 of the electrode may be positioned relatively close to or in contact with the upper surface of the sheet-like member 640. That is, the electrode end 250 is bent toward the side opposite to the side where the diaphragm 300 is located, and the edge 255 of the bent electrode end 250 is positioned above rather than below the sheet-like member 640. Since the electrode 200 is interposed between the end edge 255 and the diaphragm 300, the influence of the "sharp edge" is suppressed, and damage to the diaphragm in the electrolytic cell can be suppressed.

[0068] In such an aspect, a region inside the end edge 255 may be joined. That is, a region inside the end edge in the planar direction of the electrode may be joined. In FIG. 13, at “point a”, the electrode 200 and the electrode base 280 may be joined via the thin plate-like member 640. It can be said that the electrode 200, the thin plate-like member 640, and the electrode base 280 may be joined to each other inside the end edge 255. The joining may be welding, for example, spot welding. When the thin plate-like member 640 is made of metal and spot welding is performed as the joining, the current during spot welding is more stabilized and a stronger joining can be achieved. In such an aspect, the electrode end is bent so that the end edge of the electrode is positioned on the upper surface of the thin plate-like member provided as an intervening member on the electrode base, and a joining portion may exist in a region inside the end edge. The “joining portion” referred to here is preferably a portion where the electrode 200, the thin plate-like member 640, and the electrode base 280 are joined to each other. When welding is performed, the “joining portion” corresponds to the welded portion.

[0069] In the aspect of FIG. 14, the thin plate-like members 640 are provided on the upper side and the lower side so as to be paired. The upper thin plate-like member 640A has at least a portion positioned above the end edge 255 of the electrode. On the other hand, the lower thin plate-like member 640B is positioned below the end edge 255 of the electrode as a whole. The lower thin plate-like member 640B corresponds to the thin plate-like member 640 in FIG. 13 described above. That is, the electrode end 250 is bent so that the end edge 255 of the electrode is positioned on the upper surface of the thin plate-like member 640B directly disposed on the electrode base 280. In such an aspect, since the end edge 255 of the electrode is sandwiched between the upper thin plate-like member 640A and the lower thin plate-like member 640B, the effect of suppressing diaphragm damage is higher.

[0070] Even in the aspect of FIG. 14, a region inside the end edge 255 may be joined in the same manner as the aspect of FIG. 13. That is, a region inside the end edge in the planar direction of the electrode may be joined. In FIG. 14, at "point a", the electrode 200 and the electrode base 280 may be joined via the thin plate-like member 640. It can be said that the electrode 200, the upper and lower thin plate-like members 640A and 640B, and the electrode base 280 may be joined to each other inside the end edge 255. The joining may be welding, for example, spot welding. When the thin plate-like member 640 is made of metal and welding is performed as the joining, the current during spot welding can be more stabilized, resulting in a stronger joining. Even in such an aspect, the electrode end is bent so that the end edge of the electrode is positioned on the upper surface of the thin plate-like member provided as an intervening member on the electrode base (particularly so that the end edge of the electrode is positioned on the upper surface of the lower thin plate-like member), and a joining portion may exist in a region inside the end edge. Preferably, a portion where the electrode 200, the thin plate-like member 640, and the electrode base 280 are joined to each other may exist in such a region.

[0071] Although not limiting the present invention, more specific matters regarding the exemplary aspects of FIGS. 13 and 14 will be mentioned. The thin plate-like member 640 (640A, 640B) may be, for example, a metal foil. Also, the electrode 200 may be a flexible electrode 200A, and as an example, it may be a mesh opening electrode having a mesh opening. When welding is performed in a region inside the end edge 255 (particularly when spot welding is performed), the welded portion provided as the joining portion may be a dot-like welded portion.

[0072] (Aspect in the non-end region) This aspect is an aspect in which an intervening member is provided in a non-end region other than the end region of the electrode. In the exemplary aspect shown in FIG. 15, a thin plate-like member 640 is used for attaching the electrode as the intervening member, and the intervening member is provided particularly in a region other than the electrode end. In the exemplary aspect shown in FIG. 16, a wire-like member 660 is used for attaching the electrode as the intervening member, and the intervening member is provided particularly in a region other than the electrode end. In such an aspect, it can be said that a thin plate-like member and / or a wire-like member are provided as intervening members in a region of the non-peripheral portion of the electrode that is not the peripheral edge portion of the electrode.

[0073] As can be seen from the aspects of FIGS. 15 and 16, the intervening member 600 may be provided particularly in a region where the conductive elastic body 400 is disposed. As shown in the drawing, when a plurality of conductive elastic bodies 400 are used, it is preferable that the intervening member 600 is disposed between adjacent conductive elastic bodies. This is because the conductive elastic body 400 does not become an obstacle and the intervening member can be more reliably disposed between the electrode and the electrode base.

[0074] The installation of the intervening member in the non-end region contributes to a high degree of freedom in attaching the electrode to the electrode base. That is, in the present invention, in addition to or instead of providing the intervening member at the end of the electrode according to the size and type of the electrode used, the intervening member can be provided in the non-end region of the electrode.

[0075] (Electrode temporary fixing aspect) This aspect is an aspect in which the electrode is temporarily fixed by the intervening member. That is, the electrode may be temporarily fixed to the electrode base by the above-described attachment.

[0076] In an electrolytic cell, the electrolytic cell units are operated in a state where they are combined with a diaphragm interposed therebetween. Prior to the assembly of the electrolytic cell, it is preferable that the electrodes are temporarily fixed to the electrolytic cell units. This is because the electrolytic cell is assembled by standing the electrolytic cell units (see Fig. 3). Further, for maintenance, the tank may be disassembled to separate the combination of the electrolytic cell units. In such a case, if the temporary fixing is made by an intervening member, the electrode can be removed from the electrode base, and cleaning of the electrode base, electrode replacement, etc. can be performed more easily.

[0077] As used in the present invention, "temporary fixing" means fixing the electrodes so that they do not shift or fall off from the units when the electrode tank units are combined to form the electrode tank. Therefore, in "temporary fixing", only a part of the electrode is joined to the electrode base rather than the whole electrode being joined to the electrode base. In such a mode of temporary fixing, it can be said that the electrode is locally joined to the electrode base.

[0078] The intervening member used for temporary fixing does not need to be very large in size. For example, taking the cross-sectional view of the intervening member 600 as shown in Fig. 8 as an example, the width dimension W of the intervening member 600 is about 0.5 mm to 10 mm, and the height dimension H of the intervening member 600 (particularly the dimension H of the portion located between the electrode and the electrode base) may be about 0.5 mm to 10 mm. In the case where there is a difference in the width of the intervening member (that is, the width dimension is not constant), the width dimension W refers to the maximum width dimension among them. Similarly, in the case where there is a difference in the height of the intervening member (that is, the height dimension is not constant), the height dimension H refers to the maximum height dimension among them.

[0079] When the intervening member is locally used for the electrode region, the portion for attachment is similarly local, and it is easy to release the attachment state of the electrode to the electrode base. Since a thin plate-like member or a wire-like member can be easily provided partially for the electrode region as the intervening member, it is easy to release the attachment state of the electrode to the electrode base. Although it is only an example, when spot welding is performed through the intervening member, the joint portion between the electrode and the electrode base becomes "spot-like", and it is easy to remove the electrode from the electrode base when performing, for example, electrode replacement as part of maintenance.

[0080] (Aspect peculiar to the zero-gap type) This aspect is an aspect peculiar to the zero-gap type electrolytic cell. In the zero-gap type, mutual adhesion can be achieved between the anode, the ion exchange membrane, and the cathode (see Fig. 1). In the ion exchange membrane, damage is likely to be caused by the adhering electrodes. Therefore, when the electrolytic cell is a zero-gap type electrolytic cell (for example, a zero-gap type brine electrolytic cell), the effects of the present invention are likely to become apparent.

[0081] For example, if one of the anode and the cathode is relatively flexible with respect to the other electrode, more suitable adhesion is achieved between the anode, the ion exchange membrane, and the cathode. However, this usually means that it is easy to cause damage to the ion exchange membrane. In the present invention, even under such adhesion conditions, by using an "intervening member" as the electrode attachment member, the influence of such an electrode attachment member on the ion exchange membrane is reduced as much as possible, and damage to the ion exchange membrane can be suppressed. That is, in such a case, it can be said that one of the anode and the cathode is relatively flexible with respect to the other electrode, and an intervening member is provided for that one electrode.

[0082] From the same perspective, if a conductive elastic body is provided in the electrolytic cell, although more suitable adhesion is achieved between the anode, the ion exchange membrane, and the cathode, it generally means that the ion exchange membrane is likely to be damaged. That is, when the conductive elastic body is provided on one back side such that one of the anode and cathode electrodes is pressed against the other electrode by the conductive elastic body, suitable adhesion can be obtained, but on the other hand, the ion exchange membrane is likely to be damaged (for example, when the cathode, particularly a cathode made of a conductive porous base material, is pressed against the anode side through the ion exchange membrane, the conductive porous base material usually easily causes damage to the ion exchange membrane). Even under such conditions, by using the "intervening member" as the electrode mounting member according to the present invention, the influence of such an electrode mounting member on the ion exchange membrane can be reduced as much as possible, and damage to the ion exchange membrane can be suppressed.

[0083] [Electrolytic cell unit of the present invention] The electrolytic cell unit of the present invention is a unit for constructing the above-described electrolytic cell. Therefore, it refers not only to the units that are combined with each other to form the electrolytic cell, but also to the units in the state before combination and the units in the state after being once combined and then released.

[0084] Since it is a unit constituting the electrolytic cell, in the electrolytic cell unit of the present invention, at least one of the anode and cathode electrodes is attached to the electrode base by an intervening member intervening between the electrode and the electrode base where it is provided. Other matters such as more detailed matters and further specific embodiments of the electrolytic cell unit of the present invention are directly or indirectly described in the above [Basic configuration of the electrolytic cell] and [Features of the present invention], so the description is omitted to avoid duplication.

[0085] Finally, a note on the "electrode base" used in this specification is provided. As can be understood from the content described above, when the electrolytic cell is of the zero-gap (especially true zero-gap) type, the electrode base corresponds to the back plate or support plate against which the conductive elastic body is pressed. Also, based on the understanding of those skilled in the art, this electrode base corresponds to the base electrode for the flexible electrode in the electrolytic cell. For example, when the flexible electrode is a flexible cathode, it corresponds to the base cathode. Further, when the electrode base is considered from the viewpoints of function and structure, the electrode base is preferably a porous plate material that serves as a current collector plate.

[0086] As described above, the embodiments of the present invention have been explained, but these are merely typical examples within the scope of application of the present invention. Therefore, it will be easily understood by those skilled in the art that the present invention is not limited to the above-described embodiments, and various modifications can be made without changing the gist of the present invention.

[0087] For example, as the form of the intervening member described above, a thin plate shape or a wire shape has been exemplified, but the present invention is not necessarily limited thereto. The form of the intervening member may be any form as long as it is located between the electrode and the electrode base and contributes to their joining.

Industrial Applicability

[0088] The technology based on the present invention can be used in various electrolytic cells where electrolysis, that is, electrolytic decomposition, is performed. Although not limited thereto, the present invention can be used, for example, in electrolytic cells used in the soda industry, and in particular, is preferably used for electrolytic cells in which damage to the diaphragm due to the electrode is a concern.

Explanation of Reference Numerals

[0089] 100 Electrolytic cell unit 100’ Electrolytic cell unit 100'' Electrolytic cell unit 150 Support frame for electrode 200 Electrode 200A Cathode 200B Anode 210 Strand 250 End portion of electrode 250’ Bending portion 255 End edge of the electrode 257 Bending location 280 Electrode base (e.g., cathode base) 300 Diaphragm (e.g., ion exchange membrane) 400 Conductive elastomer 450 Elastic portion 600 Intervening member 640 Sheet-like member 640A Upper sheet-like member 640B Lower sheet-like member 660 Wire-like member 800 Former electrode fixing pin 850 Flange portion

Claims

1. An electrolytic cell comprising at least an anode, a cathode, a diaphragm between the anode and the cathode, and a conductive elastic body, At least one of the anode and the cathode is attached to the electrode base by an intervening member interposed between the electrode and the electrode base, the conductive elastic body is provided between the anode or the cathode and the electrode base; the intervening member is a member that is positioned in a region between the electrode and the electrode base in a cross-sectional view, and that at least partially contacts both the electrode and the electrode base, and is provided at least in an end region that is a peripheral region of the electrode and in a non-end region other than the end region, The electrolytic cell, wherein the end region is a peripheral region of the electrode that is 1 mm to 3 cm from the end edge.

2. 2. The electrolytic cell according to claim 1, wherein the intervening member is in the form of a thin plate or wire having a thickness thinner than that of the electrode.

3. 3. The electrolytic cell according to claim 1, wherein the electrode and the electrode base are joined to each other by the intervening member.

4. 4. The electrolytic cell according to claim 1, wherein the electrode and the electrode base are welded to each other by the intervening member.

5. 5. The electrolytic cell according to claim 1, wherein the intervening member is disposed on the distal side of the diaphragm relative to the electrode.

6. 2. The electrolytic cell according to claim 1, wherein the electrode end is bent so that the end edge of the electrode is positioned on the upper surface of a thin plate-like member that is provided as the intervening member on the electrode base and has a thickness thinner than the electrode, and the joint is present in a region inside the end edge.

7. 7. The electrolytic cell according to claim 1, wherein the electrode is locally joined to the electrode base by the attachment.

8. 8. The electrolytic cell of claim 1, wherein at least one of the electrodes comprises a conductive porous substrate.

9. 9. The electrolytic cell according to claim 1, wherein one of the anode and the cathode is flexible relative to the other of the anode and the cathode, and the intervening member is provided on the one electrode.

10. 10. The electrolytic cell according to claim 9, wherein the conductive elastic body is provided on the rear side of one of the electrodes so that the one electrode is pressed against the other electrode by the conductive elastic body.

11. The electrolytic cell according to any one of claims 1 to 10, wherein the diaphragm is an ion exchange membrane.

12. The electrolytic cell according to any one of claims 1 to 11, wherein the electrolytic cell is a zero-gap type sodium chloride electrolytic cell.

13. An electrolytic cell unit for constructing the electrolytic cell according to any one of claims 1 to 12.

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