Electrolyzer

Abstract

To provide an electrolytic bath helped by a reuse of an anode porous base material.SOLUTION: In an electrolytic bath having an anode, a cathode, a barrier membrane, a support body frame, the anode and one electrode of the cathode have an electrode conductor and a conductive porous base material that is arranged on the electrode conductor and has flexibility, an end of the conductive porous base material is configured with the conductive porous base material extending through between a base of the anode and the support body frame in a cross-sectional view and a packing member between the anode conductor and the support body frame.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an electrolytic cell, in particular an electrolytic cell comprising at least an anode, a cathode, a diaphragm and a support frame. [Background technology]

[0002] Currently, electrolysis is used in various industries. Electrolytic cells are used to perform electrolysis, i.e., electrolysis. Electrolytic cells come in a variety of types depending on their use, but they at least have an anode and a cathode. For example, cells in which electrolysis of an aqueous solution of sodium chloride is performed can extract chlorine, hydrogen, and sodium hydroxide (also known as caustic soda), and are used to produce the raw materials that are the basis of the chemical industry. They are also used to electrolyze alkaline aqueous solutions used in hydrogen production. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication (WO) No. 2012 / 091051 [Patent Document 2] Patent No. 5108043 [Patent Document 3] Patent No. 5970250 [Patent Document 4] JP 2012-140652 A [Patent Document 5] JP 2000-178781 A [Patent Document 6] JP 2011-117047 A Summary of the Invention [Problem to be solved by the invention]

[0004] In electrolytic cells, a diaphragm is often installed to prevent mixing of the substances produced at the anode and the cathode. The process of electrolyzing a sodium chloride solution using an ion exchange membrane as a diaphragm is also called "ion exchange membrane chlor-alkali electrolysis". It is also used for electrolyzing an alkaline solution used in hydrogen production.

[0005] There are various types of electrolytic cells used in ion exchange membrane salt electrolysis, among which the zero-gap type is the mainstream. In the zero-gap type electrolytic cell, the anode, the diaphragm, and the cathode are brought into close contact with each other to reduce the distance between the electrodes, thereby reducing the electrolyte resistance and power consumption. In the "zero-gap" type electrolytic cell, for example, one of the anode and the cathode is provided with an electrode conductor having a relatively high rigidity and a conductive porous substrate arranged on the electrode conductor and having a relatively high flexibility, while the other is relatively rigid. Furthermore, it is considered that the conductive porous substrate of one electrode is structured so that it is in close contact with the opposing electrode having a high rigidity when pressed by the deformation of an elastic body, while the other is structured so that it is high rigidity and has a rigidity that is less deformed even when pressed against the diaphragm. In such an electrolytic cell, by providing a conductive elastic body between the conductive porous substrate and the electrode conductor in one of the electrodes, the pressure required for tight contact between the rigid electrode (e.g., an anode), the diaphragm, and the conductive porous substrate (e.g., a cathode) can be provided by the elastic force (i.e., reaction force) of the conductive elastic body.

[0006] The inventors of the present application realized that there were still problems to be overcome with conventional electrolytic cells, and found it necessary to take measures to address these problems. Specifically, they found the following problems:

[0007] In an electrolytic cell, when the components (e.g., electrodes) in the electrolytic cell deteriorate over time due to operation, electrolysis is no longer performed efficiently. In order to continue efficient electrolysis in the electrolytic cell, for example, it becomes necessary to replace the electrodes. In replacing the other electrode in the above-mentioned zero-gap electrolytic cell, in addition to removing the other electrode to be replaced, it may be necessary to remove one of the electrodes that is not to be replaced due to its structure. For example, in order to correct the flatness of one electrode (e.g., an anode) and perform electrolysis efficiently, it is necessary to remove the conductive porous substrate of the other electrode (e.g., a cathode).

[0008] Since the conductive porous substrate is installed under a stress, once it is removed from the electrolytic cell, it is difficult to return to its original shape, and it may not be possible to reuse it. In such cases, it is necessary to discard the removed conductive porous substrate and replace it with a new conductive porous substrate. Furthermore, in recent years, there has been a trend toward thinner conductive porous substrates in order to improve the performance of electrolytic cells for the purpose of energy saving, and the strength of the conductive porous substrate has decreased, making it more susceptible to damage such as bending, sharpening, and cutting. Therefore, there is a demand for a method of fixing the conductive porous substrate to the electrolytic cell that reduces damage to the conductive porous substrate.

[0009] In addition, when the conductive porous substrate is fixed using a pin made of fluororesin, if the upper part of the pin protrudes beyond the conductive porous substrate, there is a problem that the pin comes into contact with the ion exchange membrane, which is a diaphragm, and is likely to damage the ion exchange membrane. Furthermore, since the insertion part of the pin of the conductive porous substrate is deformed after the pin is removed, the pin cannot be reused once it is removed. Furthermore, when the conductive porous substrate is attached and detached using a pin made of fluororesin, the pin made of fluororesin is plastically deformed, so that the fixed conductive porous substrate is likely to come off, and if it comes off, there is a risk of damaging the ion exchange membrane. In such a case, in addition to the conductive porous substrate, it is necessary to replace other members (pin and ion exchange membrane). Therefore, there is also a need for fixing the conductive porous substrate to the electrolytic cell so as to reduce damage to other members (e.g., diaphragm).

[0010] The present invention has been made in view of the above problems. That is, a main object of the present invention is to provide an electrolytic cell which is more conducive to reuse (particularly, reuse of the conductive porous substrate). [Means for solving the problem]

[0011] The inventors of the present application attempted to solve the above problems by taking a new approach, rather than simply extending the conventional technology, and as a result, they have invented an electrolytic cell that achieves the above-mentioned main object.

[0012] In the present invention, An electrolytic cell comprising an anode, a cathode, a diaphragm, and a support frame, One of the anode and the cathode has an electrode conductor and a flexible conductive porous substrate disposed on the electrode conductor; the conductive porous substrate extends such that an end portion of the conductive porous substrate passes between the electrode conductor and the support frame in a cross-sectional view; An electrolytic cell is provided, comprising a packing member between the electrode conductor and the support frame. Effect of the Invention

[0013] According to the present invention, it is possible to provide an electrolytic cell which is more conducive to reuse in electrode replacement of the electrolytic cell.

[0014] More specifically, in the present invention, the end of the conductive porous substrate of at least one of the anode and cathode (electrolysis) electrodes extends between the electrode conductor and the support frame in a cross-sectional view, and a filler is provided between the electrode conductor and the support frame, so that even if the conductive porous substrate is once removed during electrode replacement, the conductive porous substrate can be easily restored to its original state before attachment. Therefore, the conductive porous substrate can be reattached and used with little damage, which contributes to reuse. Furthermore, according to the present invention, the conductive porous substrate can be attached and detached to the electrolytic cell with reduced damage to other members (e.g., diaphragm). Therefore, the present invention contributes to reuse. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram for illustrating the configuration of an electrolytic cell. [Diagram 2] FIG. 2 is a perspective view showing an example of a conductive elastic body used in an electrolytic cell. [Diagram 3] FIG. 3 is a schematic perspective view for explaining a combination of electrolytic cell units with a diaphragm interposed therebetween. [Figure 4] FIG. 4 is a schematic horizontal cross-sectional view of an electrolytic cell according to an exemplary embodiment. [Diagram 5] FIG. 5 is a perspective view illustrating that the end of the conductive porous substrate of the electrode extends between the electrode conductor and the support frame in a cross-sectional view, and that a filler is provided between the electrode conductor and the support frame. [Figure 6] FIG. 6 is a schematic cross-sectional view for explaining an electrolytic cell serving as one embodiment (first embodiment) of the present invention. [Figure 7] FIG. 7 is an enlarged cross-sectional view of FIG. 6 for illustrating a filler member provided between the electrode conductor and the support frame. [Figure 8] FIG. 8 is a schematic diagram for illustrating a sharp end edge of a conductive porous substrate. [Figure 9] FIG. 9 is an enlarged cross-sectional view illustrating a filler member provided between an electrode conductor and a support frame of an electrolytic cell unit serving as another embodiment (second embodiment) of the present invention. [Figure 10] FIG. 10 is a perspective view for explaining a filler member provided between an electrode conductor and a support frame of an electrolytic cell serving as still another embodiment (third embodiment) of the present invention. [Figure 11] FIG. 11 is a schematic cross-sectional view for explaining an electrolytic cell serving as still another embodiment (fourth embodiment) of the present invention. [Figure 12] FIG. 12 is a schematic cross-sectional view for explaining a modified example of an electrolytic cell provided as another embodiment (second embodiment) of the present invention. [Figure 13] FIG. 13 is a schematic cross-sectional view for explaining a modified electrolytic cell provided as another embodiment (a combination of the second and fourth embodiments) of the present invention. [Figure 14] FIG. 14 is a schematic cross-sectional view for explaining a modified electrolytic cell provided as another embodiment of the present invention (a combination of the modified second embodiment and the fourth embodiment). [Figure 15] FIG. 15 is a diagram illustrating that in an electrolytic cell provided as a modified example of an embodiment (first embodiment) of the present invention, the protruding height of the filler member is less than the thickness of the gasket. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an electrolytic cell according to an embodiment of the present invention will be described in more detail with reference to the drawings. Various elements in the drawings are merely shown as schematic and illustrative elements for the understanding of the present invention, and the appearance and dimensional ratios may differ from those of the actual objects.

[0017] In this specification, the term "electrolytic cell" refers in a broad sense to an apparatus for performing electrolysis, and in a narrow sense to an apparatus including at least an anode, a cathode, a diaphragm provided between the electrodes, and a support frame. Similarly, in the present invention, the term "electrode for electrolysis" refers in a broad sense to an electrode used in an apparatus for performing electrolysis, and in a narrow sense to an anode and / or cathode used in such an apparatus.

[0018] The directions of "up and down" and "left and right" described directly or indirectly in this specification correspond to the up and down directions and left and right directions in the drawings, respectively. More specifically, in the embodiment shown in FIG. 6, the direction along the planar direction of the electrode for electrolysis corresponds to the left and right direction, and the direction perpendicular thereto corresponds to the up and down direction. During operation of the electrolytic cell, the electrode for electrolysis in the embodiment shown in FIG. 6 and the like is often used in an upright orientation as shown in FIG. 5. That is, the electrode for electrolysis is often used with its orientation changed by approximately 90° from the state shown in FIG. 6. Therefore, the orientation of the cell and its components may differ between when the electrolytic cell is in use (particularly, when the electrolytic cell is in operation with the units constituting the electrolytic cell combined) and when it is not in use, particularly when it is not in operation before the units constituting the electrolytic cell are combined.

[0019] Various numerical ranges mentioned in this specification are intended to include the lower and upper limit values ​​themselves. That is, for example, a numerical range such as 1 to 10 is interpreted as including the lower limit "1" and the upper limit "10."

[0020] 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 described. In the following description, electrodes for the electrolytic cell, i.e., electrodes for electrolysis, will be simply referred to as "electrodes" or, more specifically, as "anodes" or "cathodes."

[0021] [Basic configuration of electrolytic cell] The electrolytic cell of the present invention comprises an anode, a cathode, a diaphragm disposed between the electrodes, and a support frame. The anode and the cathode are electrodes for externally supplying 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 where an oxidation reaction can occur during operation of the electrolytic cell. On the other hand, the cathode is an electrode typically connected to the negative electrode of the external electrode, and is an electrode where a reduction reaction can occur during operation of the electrolytic cell.

[0022] The diaphragm is typically a member that separates the anode chamber from the cathode chamber. Preferably, the diaphragm is provided to prevent mixing of the material produced at the anode and the material produced at the cathode. In the present invention, the diaphragm may be one that is conventionally used in electrolysis. For example, the diaphragm is an ion exchange membrane. As only one example, in electrolytic cells used in the soda industry, a cation exchange membrane may be used as the diaphragm.

[0023] The electrolytic cell may further include a conductive elastic body. The conductive elastic body contributes to the passage of current between the electrodes due to its "conductivity," while being capable of exerting a pressing force against the electrodes due to its "elasticity." In other words, the conductive elastic body corresponds to a conductive member capable of exerting a reaction force in the electrolytic cell, and has at least a structure capable of elastic deformation in order to provide such a reaction force.

[0024] An exemplary configuration of an electrolytic cell is shown in FIG. 1. As shown in the figure, in the electrolytic cell, a conductive elastic body is used for an electrode assembly at least composed of an anode, a cathode, and an ion exchange membrane (as a diaphragm) between the electrodes. In such an electrolytic cell, the reaction force of the conductive elastic body is used to press the electrode assembly at least composed of an anode, a cathode, and an ion exchange membrane between the electrodes. Specifically, the conductive elastic body is used in a state in which it is subjected to elastic deformation on the back side of the electrode assembly, and a pressing force is applied to the electrode assembly by the elastic force (i.e., the reaction force) provided by the conductive elastic body. In particular, the conductive elastic body subjected to elastic deformation works to apply a pressing force from one electrode toward the other electrode, thereby promoting the close contact of the electrode assembly. In other words, the presence of the conductive elastic body brings about close contact between the anode, the ion exchange membrane, and the cathode, and the electrolytic cell can function suitably as a so-called "zero gap" type.

[0025] The conductive elastic body used in the electrolytic cell may have any form as long as it generates an elastic repulsive force. For example, the conductive elastic body may have various forms such as an elastic cushion, an elastic mat, and a leaf spring. Examples of the elastic mat include a member made of a metal coil body, a metal nonwoven fabric, and a knitted or woven fabric made of a metal wire. As only one specific example, the conductive elastic body 400 may have a wavy curved elastic part 450 as shown in FIG. 2. The conductive elastic body 400 is used in the electrolytic cell in a state in which it is subjected to elastic deformation so as to develop spring characteristics. More specifically, for example, the conductive elastic body is provided in the electrolytic cell in a state in which it is subjected to deformation so that the wavy curvature of the elastic part 450 is reduced. In the conductive elastic body thus deformed, a reaction force acts to take the original shape, and the spring characteristics are developed. In a large electrolytic cell, the conductive elastic body 400 is often provided as a plurality of conductive elastic bodies rather than being used singularly.

[0026] In the electrolytic cell, one of the anode and cathode has an electrode conductor that may have rigidity and a conductive porous substrate that is disposed on the electrode conductor and has flexibility. For example, as shown in FIG. 3, the cathode has an electrode conductor (cathode base) 280 that is particularly relatively rigid, and a conductive porous substrate 200A that is disposed on the electrode conductor 280 and has flexibility. The anode 200B has an electrode conductor (anode base) that has rigidity. The conductive porous substrate 200A may be, for example, a mesh opening electrode that has mesh openings. By way of example only, the electrode may be made of expanded metal, for example, a wire mesh such as a plain weave mesh and a twill weave mesh, or a punched metal.

[0027] The electrode conductor 280, which can be the electrode base, corresponds to a back plate or support plate against which the conductive elastic body 400 is pressed when the electrolytic cell is of a zero-gap (particularly true zero-gap) type. Also, based on the recognition of a person skilled in the art, this electrode conductor 280 corresponds to a base electrode for a flexible electrode in the electrolytic cell, and corresponds to a base cathode when the flexible electrode is a flexible cathode, for example. Also, from the viewpoint of function and structure, the electrode conductor 280 is preferably a porous plate material that serves as a current collector plate.

[0028] In a preferred embodiment, both the anode and the cathode may have the conductive porous substrate 200A. For example, both electrodes may be made of expanded metal or plain weave mesh, or one electrode may be made of expanded metal and the other electrode may be made of plain weave mesh. That is, both the anode and the cathode may be made of expanded mesh or plain weave mesh, or one of the anode and the electrode may have expanded mesh and the other a plain weave mesh. From the viewpoint of being able to exhibit corrosion resistance (also called corrosion resistance), each of the anode and the cathode may be made of at least one selected from the group consisting of titanium, nickel, stainless steel, tantalum, zirconium, niobium, and the like. In addition, each of such anodes and cathodes may be supported with a suitable catalyst. The opening ratio in 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%, etc.

[0029] The electrolytic cell is preferably a zero-gap type, and has characteristics suitable for such a zero-gap type. As one of such characteristics, the anode and cathode are characterized in terms of 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 cathode is relatively flexible with respect to the other, and conversely, the other is relatively rigid with respect to the one. As a result, the relatively flexible electrode can bend under the reaction force of the conductive elastic body 400, while the relatively rigid electrode can receive the bending through the ion exchange membrane 300. If the anode and cathode are relatively different from this viewpoint, the mutual adhesion between the anode, the ion exchange membrane, and the cathode becomes more suitable, and the electrolytic cell can function more suitably as a "zero-gap type". This is particularly true when the electrolytic cell is large. That is, it is particularly true when the electrode main surface that requires pressing for zero gap is large, as typified by the zero-gap type salt electrolysis.

[0030] To obtain a larger amount of the desired electrolysis product, a larger electrolytic cell is used, and the main surfaces of the electrodes (particularly, the main surfaces where the anode and cathode face each other) are accordingly larger. A large zero-gap electrolytic cell is preferably composed of a plurality of electrolytic cell units, and each of the electrolytic cell units has a large electrode main surface on both opposing side surfaces. As an example, a so-called "bipolar" electrolytic cell is described with reference to FIG. 3. A cathode 200A (e.g., a cathode surface made of expanded metal) is provided on one of the opposing side surfaces of an electrolytic cell unit 100, and an anode 200B (e.g., an anode surface made of expanded metal) is provided on the other of the opposing side surfaces. In an electrolytic cell, such electrolytic cell units are connected in a plurality of layers so as to be stacked on top of each other via an ion exchange membrane (particularly a cation exchange membrane) 300. In particular, adjacent electrolytic cell units are stacked so that the cathode surface of one electrolytic cell unit 100' faces the anode surface of the other electrolytic cell unit 100''. In this way, an electrolytic cell is constructed by combining a plurality of electrolytic cell units via ion exchange membranes 300. Note that an electrolytic cell constructed from a plurality of electrolytic cell units is not limited to a "bipolar type" and may be a "monopolar type". In other words, the electrode cell units constituting the electrolytic cell are not limited to bipolar type electrolytic cell units having an anode portion and a cathode portion on both opposing sides, but may be "monopolar type" electrolytic cell units having only an anode portion and only a cathode portion on both opposing sides. In such a case, an electrolytic cell can be constructed by combining electrolytic cell units having only an anode portion and an electrolytic cell unit having only a cathode portion so as to be alternately arranged via ion exchange membranes.

[0031] An electrolytic cell composed of an electrolytic cell unit has a relatively large electrode main surface size, which is preferable because the desired electrolytic reaction occurs through the large electrode surface, but it is difficult to maintain the flatness of the electrode surface. Specifically, the larger the electrode main surface size, the more likely it is that the influence of bending due to its own weight cannot be ignored, and the attachment to the electrode supporter also has an effect, making it difficult to obtain a completely flat electrode main surface. For example, in the electrolytic cell unit 100 (100', 100'') as illustrated in FIG. 3, the main surface size of the anode surface and the cathode surface is on the order of meters rather than on the order of several centimeters. Even if the electrodes are made rigid to provide a more suitable flat surface, such a large electrode main surface has a flatness of, for example, about ±0.5 mm to 1.0 mm for the above reasons, and it is difficult to obtain a completely flat surface (i.e., a flatness of 0 mm). In other words, in a large electrolytic cell, the main surface of a rigid electrode tends to have localized irregularities when viewed microscopically, even if it appears flat macroscopically.

[0032] When electrodes that are not completely flat are brought into close contact with each other through the ion exchange membrane 300, the unevenness may impair the uniformity of the current distribution. Therefore, in a suitable electrolytic cell, the electrode that pairs with the rigid electrode is a soft flexible electrode. As a result, even if the electrodes are tightly brought into close contact with each other through the ion exchange membrane 300, the flexible electrode will bend to follow the unevenness of the rigid electrode surface, and as a result, the non-uniformity of the current distribution can be more suitably prevented. As an example, the anode may be made of a relatively hard rigid expanded metal, while the cathode may be made of a relatively soft flexible expanded metal. 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 300. In this case, the flexible expanded metal of the cathode is pressed toward the rigid expanded metal of the anode by the reaction force of the conductive elastic body 400, and at that time, the flexible expanded metal of the cathode can locally elastically deform according to the flatness of the main surface of the rigid expanded metal of the anode. Therefore, even if the electrolytic cell units 100 are fixed tightly to each other under conditions in which the reaction force of the conductive elastic body acts strongly, the anode, ion exchange membrane 300, and cathode are suitably adhered to each other, and undesirable phenomena such as non-uniform current distribution are unlikely to occur.

[0033] For further understanding of the electrolytic cell, Fig. 4 is shown. Fig. 4 corresponds to a vertical cross-sectional view of an example embodiment of the electrolytic cell. In other words, Fig. 4 corresponds to a cross-sectional view of the cell (particularly a combination of electrolytic cell units) shown in Fig. 3 cut horizontally. In the embodiment shown in Fig. 4, a flexible cathode 200A made of expanded metal, a diaphragm 300, and a rigid anode 200B made of expanded metal are stacked in that order, and a conductive elastic body 400 is provided on the back side of the cathode 200A (i.e., the side opposite to the side where the diaphragm 300 is installed). Since the conductive elastic body 400 is provided by being subjected to deformation so as to be constricted between the cathode 200A of the expanded metal and the cathode base 280 (as an electrode conductor) (more specifically, such constriction is caused by the mutual clamping of a plurality of electrolytic cell units connected to each other, resulting in deformation of the conductive elastic body), the elastic force of the conductive elastic body 400 is directly applied to the flexible cathode 200A of the expanded metal that is in direct contact with the elastic part of the conductive elastic body 400. As a result, the flexible cathode 200A of the expanded metal is biased so as to be pressed toward the rigid anode 200B of the expanded metal, resulting in close contact between the flexible cathode 200A, the diaphragm 300, and the rigid anode 200B. Note that the rigid anode 200B itself, which is an electrode that is not in direct contact with the conductive elastic body, is fixed immovably to the electrode support of the electrolytic cell unit 100, etc., and therefore acts to receive the elastic force of the conductive elastic body 400, contributing to close contact.

[0034] 6, in the electrolytic cell, a gasket 260 is placed on a support frame 290. The gasket 260 is placed so as to surround the electrode chamber in a plan view, thereby providing a seal between the diaphragm 300 and the support frame 290 in a cross-sectional view, and preventing leakage of the electrolyte in the electrode chamber and / or gas and electrolyte generated in the electrode chamber to the outside of the electrode chamber.

[0035] [Features of the present invention] The present invention is characterized by the shape of the conductive porous substrate in relation to the electrolytic cell. In particular, the present invention is characterized by the shape of the end of the conductive porous substrate. The shape of the end of the conductive porous substrate 200A is shown typically in Figs. 5, 6 and 7. Fig. 5 shows a perspective view of a part of the electrolytic cell, Fig. 6 shows a partial cross section of the electrolytic cell, and Fig. 7 shows an enlarged view of a part of Fig. 6, showing the shape before the electrolytic cell units 100 are combined with each other. That is, Figs. 5 to 7 show the state before the spring characteristics of the conductive elastic body 400 are expressed by clamping the electrolytic cell units 100 with each other, and before the diaphragm 300 and the electrode are in close contact with each other.

[0036] Specifically, as shown in Figures 5 to 7, the conductive porous substrate 200A in at least one of the anode and cathode electrodes extends between the electrode conductor 280 and the support frame 290 in a cross-sectional view, and has a filler member 700 between the electrode conductor 280 and the support frame 290. As can be seen particularly from Figure 7, the end of the conductive porous substrate 200A has a filler member 700 between the electrode conductor 280 and the support frame 290 where the conductive porous substrate 200A extends between the electrode conductor 280 and the support frame 290 in a cross-sectional view.

[0037] In this specification, "the end of the conductive porous substrate 200A extends between the electrode conductor 280 and the support frame 290 in a cross-sectional view" refers to a configuration in which the end of the conductive porous substrate 200A is positioned between the electrode conductor 280 and the support frame 290, but a filler member 700 is provided between the electrode conductor 280 and the support frame 290.

[0038] The effects of the present invention will be described in detail. When the conductive porous substrate 200A extends between the electrode conductor 280 and the support frame 290 and has a filler 700 between the electrode conductor 280 and the support frame 290, even when the conductive porous substrate 200A of one electrode is removed to replace the other electrode, the conductive porous substrate 200A is easily restored to its original state. In particular, the conductive porous substrate 200A can be recovered with reduced damage such as bending, sharpening, and cutting. Therefore, even if the other electrode is replaced with a new electrode, the conductive porous substrate 200A can be reattached, which contributes to the reuse of the conductive porous substrate 200A in electrode replacement.

[0039] In order to deepen understanding of the effects of the present invention, the conventional problems will be mentioned. In a bipolar element, when only the anode 200B that has reached the end of its life is replaced and updated, in order to make the flatness of the anode surface a predetermined flatness after the anode 200B is updated, it is necessary to correct the flatness by pressing from both the cathode base 280 side and the anode 200B surface side. In this operation, in order to not affect the conductive porous substrate 200A, it is necessary to remove the conductive porous substrate 200A. Here, conventionally, the end of the conductive porous substrate has been fixed by, for example, a method of joining the end to another member by welding, a method of bending and hooking it on another member, and a method of driving in a pin made of fluororesin. For this reason, the conductive porous substrate after removal was often in a state far removed from the conductive porous substrate before attachment. Specifically, in the process of removal, the conductive porous substrate was often torn or wrinkled, and the conductive porous substrate after removal did not return to its original state before attachment. In addition, in the process of reattaching, the conductive porous substrate often becomes bent, sharp, cut, etc., and the reattached conductive porous substrate is in a state that is significantly different from the conductive porous substrate before removal. Therefore, conventionally, the conductive porous substrate cannot be reattached and used (i.e., reused). A conductive porous substrate that is damaged by being bent, sharp, cut, etc. is difficult to repair (as described below), and efficient electrolysis in an electrolytic cell cannot be sufficiently achieved.

[0040] Furthermore, since the conductive porous substrate is finely woven, it is very difficult to repair the conductive porous substrate damaged by breakage, sharpness, or cut. For this reason, in conventional electrolytic cells, the conductive porous substrate itself has not yet reached the end of its life, but it is necessary to replace it with a new conductive porous substrate when replacing the anode. Therefore, the present inventors have studied the manner of attachment of the conductive porous substrate 200A and found that the removed conductive porous substrate 200A can be reused if it can be restored to a certain degree to its state before attachment. Based on this knowledge, the present inventors have come up with the characteristic that "the conductive porous substrate 200A in at least one of the electrodes, the anode 200B and the cathode, extends between the electrode conductor 280 and the support frame 290 in a cross-sectional view, and has a filler member 700 between the electrode conductor 280 and the support frame 290." Therefore, the electrolytic cell of this embodiment contributes to reuse (of the conductive porous substrate 200A). This allows the conductive porous substrate 200A to be reused, which is more cost-effective.

[0041] The ends of the conductive porous substrate 200A are preferably sandwiched between the electrode conductors 280 and the support frame 290. The ends are not bonded to the support frame 290 and the electrode conductors 280, making them easier to "insert and detach."

[0042] As shown in FIG. 7, the length L from the point (contact point) of the end of the conductive porous substrate 200A that is sandwiched between the electrode conductor 280 and the packing member 700 (described in detail later) to the end edge of the conductive porous substrate 200A in a cross-sectional view (in other words, the length of the part that protrudes downward from the surface including the lower surface of the electrode conductor 280) is, for example, 10 mm or less. In this embodiment, the end of the conductive porous substrate 200A is sandwiched and fixed between the electrode conductor 280 and the support frame 290 by the packing member 700. In this embodiment, in order to fix the end, it is necessary to at least secure the sandwiched part, and it is not necessary to bend it to a part corresponding to the length L. Since it is not necessary to bend the end, L can be made shorter than the conventional length (for example, 20 mm or more). Therefore, the electrolytic cell of this embodiment is more cost-effective.

[0043] The conductive porous substrate 200A is also prone to sharpening, particularly at its end edge (i.e., the edge forming the outermost edge of the electrode). This is because the electrode is often porous or open. In other words, the end edge of a porous or open electrode is prone to becoming sharp. As shown in FIG. 8, the electrode (conductive porous substrate) 200A used in the electrolytic cell may have a sharp edge that is "jagged" due to the multiple wires forming the pores or openings. In other words, the conductive porous substrate 200A is prone to having a sharp end edge due to the wires forming the pores and openings. Although a sharp end edge is usually prone to damage the diaphragm 300, in the electrolytic cell of the present invention, the end of the conductive porous substrate 200A is arranged so that the end edge faces in the opposite direction (opposite side) to the direction in which the diaphragm 300 is arranged (see FIG. 7). This allows the electrode edge to be positioned farther away from the diaphragm 300. Therefore, as a secondary effect, the present invention can effectively prevent damage to the diaphragm 300 due to contact with the end of the conductive porous substrate 200A. Therefore, the present invention also contributes to the reuse of other members (e.g., the diaphragm 300) other than the conductive porous substrate 200A.

[0044] When the conductive porous substrate is damaged by breakage, sharpness, cut, etc., the damaged portion is likely to become sharp. For example, the damaged portion caused by a cut has the above-mentioned sharp edge. Therefore, when the damaged conductive porous substrate is placed in an electrolytic cell or when the damaged conductive porous substrate is inserted into or removed from the electrolytic cell, if the damaged portion comes into contact with other members (e.g., a diaphragm) in the electrolytic cell, damage to the other members may occur. In the embodiment of the present invention, damage to the conductive porous substrate 200A by breakage, sharpness, cut, etc. is reduced, so that damage to other members in the electrolytic cell can be reduced. Therefore, the present invention also contributes to the reuse of other members other than the conductive porous substrate 200A.

[0045] (Aspect unique to the zero gap type) This embodiment is specific to a zero-gap electrolytic cell. As shown in Fig. 1, in the zero-gap electrolytic cell, the anode, the ion exchange membrane 300, and the cathode can be brought into close contact with each other, but the ion exchange membrane 300 is easily damaged by the electrodes that are in close contact with each other. Therefore, when the electrolytic cell is a zero-gap electrolytic cell (for example, a zero-gap salt electrolytic cell), the secondary effect of the present invention, that is, the suppression of damage to the diaphragm, is easily realized.

[0046] For example, when one of the anode and cathode used as the electrodes for electrolysis has relative flexibility with respect to the other electrode, more suitable adhesion is achieved between the anode, the ion exchange membrane 300, and the cathode, but this usually means that the ion exchange membrane 300 is more likely to be damaged. In the present invention, even under such a condition of adhesion, by "providing the filler member 700 between the electrode conductor 280 and the support frame 290", it is easy to arrange the electrodes so that their edges do not directly contact the ion exchange membrane 300, and damage to the ion exchange membrane 300 can be suppressed.

[0047] From a similar viewpoint, when the electrolytic cell is provided with the conductive elastic body 400, more suitable adhesion is achieved between the anode 200B, the ion exchange membrane 300, and the cathode, but on the other hand, this usually means that the ion exchange membrane 300 is easily damaged. In other words, when the conductive elastic body 400 is provided on the back side of one of the anode and cathode electrodes so that one of the electrodes is pressed against the other electrode by the conductive elastic body 400, suitable adhesion is achieved, but on the other hand, the ion exchange membrane 300 is easily damaged (for example, when the cathode, particularly the cathode having a conductive porous substrate, is pressed against the anode 200B side via the ion exchange membrane 300, the conductive porous substrate 200A usually easily causes damage to the ion exchange membrane 300). Even under such conditions, in the present invention, by "having a filler member 700 between the electrode conductor 280 and the support frame 290", it is easy to arrange the end edge of the conductive porous substrate 200A so that it does not come into direct contact with the ion exchange membrane 300, thereby suppressing damage to the ion exchange membrane 300.

[0048] Similarly, the effect of the present invention is likely to be evident when the diaphragm 300 used in the electrolytic cell is an ion exchange membrane. Ion exchange membranes used in electrolytic cells are relatively thin, for example, about 0.1 to 0.5 mm, and are often made of a material that is relatively softer than the electrodes (for example, a flexible thin film made of a fluororesin film having cation exchange groups may be used as a cation exchange membrane used in an electrolytic cell). Therefore, when an ion exchange membrane is used in an electrolytic cell, the ion exchange membrane is usually likely to be damaged by the electrodes for electrolysis. Therefore, when at least one of the electrodes for electrolysis, the anode and the cathode, is a metallic conductive porous substrate, and the diaphragm directly facing such an electrode is an ion exchange membrane, the effect of suppressing damage to the diaphragm is likely to be evident.

[0049] As described above, when the conductive porous substrate 200A is porous or has openings, the end edges of the conductive porous substrate 200A are particularly likely to become sharp. However, in the present invention, the end of the conductive porous substrate 200A passes between the electrode conductor 280 and the support frame 290 in a cross-sectional view, and the conductive porous substrate 200A extends therethrough, and a filler member 700 is provided between the electrode conductor 280 and the support frame 290, thereby suppressing the effect of sharp edges. In other words, since one of the electrodes used in the electrolytic cell has the conductive porous substrate 200A, the present invention More specifically, when at least one of the anode and cathode electrodes for electrolysis is a mesh opening electrode made of, for example, expanded metal, wire mesh such as plain weave mesh and twill weave mesh, or punched metal, and the conductive porous substrate 200A extends so that an end of such a mesh opening electrode passes between the electrode conductor 280 and the support frame 290 in a cross-sectional view, and a filler member 700 is provided between the electrode conductor 280 and the support frame 290, the effect of suppressing damage to the diaphragm is likely to become apparent.

[0050] [Filling material] As shown in FIGS. 5 to 7, the electrolytic cell of the present invention has a filler member 700 between the electrode conductor 280 and the support frame 290. In this specification, the term "filler member" refers in a broad sense to a member that is provided to fill the gap between the electrode conductor 280 (its edge) and the supporting frame 290 facing it, and in a narrow sense to a member that can act as a wedge to fix the end of the conductive porous substrate 200A by filling the specified space described above.

[0051] The stuffing member 700 has an elongated shape. Examples of the cross section of the elongated shape include a substantially circular cross section and a substantially polygonal cross section. Among these, it is preferable that the cross section of the stuffing member 700 is circular. When the cross section of the stuffing member 700 is circular, the conductive porous substrate 200A comes into contact with the rounded stuffing member 700, so that the conductive porous substrate 200A is less likely to receive excessive external force locally from the stuffing member 700, and damage is reduced, which contributes to reuse.

[0052] The stuffing member 700 fixes the end of the conductive porous substrate 200A between the electrode conductor 280 and the support frame 290. The stuffing member 700 can be attached to the support frame 290. When the stuffing member 700 is attached to the support frame 290, the end of the conductive porous substrate 200A can be more reliably fixed between the electrode conductor 280 and the support frame 290. The method of joining the stuffing member 700 and the support frame 290 includes welding, joining using an adhesive or a caulking agent, etc. For example, when the stuffing member 700 is made of metal, it is removed by a grinder, a chisel, etc., and attached to the support frame 290 by welding (more specifically, tungsten-inert gas (TIG) welding, spot welding, etc.). When the stuffing member 700 is made of resin, it is removed by a solvent, etc., and attached to the support frame 290 by an adhesive or a caulking agent, etc. Since the end of the conductive porous substrate 200A is fixed by the packing member 700 in this manner, the end of the conductive porous substrate 200A can be easily removed and reattached using the packing member 700 when replacing the electrode.

[0053] 7, the width of the stuffing member 700 corresponds to the width W of the gap between the electrode conductor 280 and the support frame 290. The width of the stuffing member 700 also corresponds to the width between the edge of the electrode conductor 280 and the opposing support frame 290. The width of the stuffing member 700 is, for example, 0.5 mm to 5 mm. When the cross section of the stuffing member 700 is substantially circular, the width of the stuffing member 700 corresponds approximately to the diameter of the circle.

[0054] 7, in cross-sectional view, the stuffing member 700 does not protrude from the surface level of the support frame 290 and the electrode conductor 280. In other words, the stuffing member 700 is disposed above the same plane including the upper surface of the support frame 290 and the upper surface of the electrode conductor 280 without protruding. For this reason, as shown in FIG. 4, when the flexible cathode 200A is biased so as to be pressed toward the rigid anode 200B in the electrolytic cell, and the flexible cathode 200A, the diaphragm 300, and the rigid anode 200B are brought into close contact with each other, the rigid anode 200B (as the other electrode) is unlikely to come into contact with the stuffing member 700, and sufficient close contact can be achieved.

[0055] Although not shown in the figure, the stuffing member 700 can be locally joined to the support frame 290. For example, if the stuffing member 700 is locally joined to the support frame 290 by welding, the stuffing member 700 can be removed by cutting only the joint. The stuffing member 700 can then be fixed by locally joining the stuffing member 700 to the support frame 290. Thus, in such a case, the stuffing member 700 can be more easily removed from the support frame 290 and more easily joined to the support frame 290. Such local joining can be, for example, a spot joint. In this regard, the local joining can be achieved by using, for example, tungsten-inert gas (TIG) welding or the like. Also, if the stuffing member 700 is locally joined to the support frame 290 by an adhesive, the stuffing member 700 can be removed by cutting only the joint.

[0056] Examples of the material of the filling member 700 include resin and metal. The resin for the filling member 700 is at least one selected from the group consisting of fluororesin, 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. Among these resins, fluororesin is preferable from the viewpoint of excellent corrosion resistance. The fluororesin may be at least one selected from the group consisting of polytetrafluoroethylene (PTFE), polytetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA), polyvinylidene fluoride (PVDF), polytetrafluoroethylene-ethylene copolymer (ETFE), polytetrafluoroethylene-hexafluoropropylene copolymer (FEP), and polychlorotrifluoroethylene (PCTFE). Examples of metals constituting the packing member 700 include Ni, Ti, and stainless steel. Among these, metal is preferable for the packing member 700. That is, the packing member 700 is preferably made of metal. If the packing member 700 is made of a metal such as Ni, it has excellent solvent resistance (corrosion resistance) compared to, for example, a packing member 700 made of resin. Therefore, the replacement period of the packing member 700 can be extended.

[0057] The electrode conductor (cathode base) 280 is a conductive member and generally has higher rigidity than the conductive porous substrate 200A. In the electrolytic cell, a conductive elastic body 400 is provided on the electrode conductor 280 so as to be supported by the electrode conductor 280, and the conductive porous substrate 200A is provided on the conductive elastic body 400. The diaphragm 300 is disposed so as to be sandwiched between the conductive porous substrate 200A and the anode 200B.

[0058] As described above, the present invention is characterized in that the conductive porous substrate 200A extends such that an end portion of the conductive porous substrate 200A passes between the electrode conductor 280 and the support frame 290 in a cross-sectional view, and a filler member 700 is provided between the electrode conductor 280 and the support frame 290. The present invention can be realized in various forms, which will be described below.

[0059] An example of a method for removing the end of the conductive porous substrate 200A from the support frame 290 and a method for (re)attaching it to the support frame 290 in response to electrode replacement will be described below.

[0060] [Removing the end of the conductive porous substrate] Removing the end of the conductive porous substrate 200A can be done, for example, by (1) removing the stuffing member 700 from the support frame 290 (stuffing member removal step); and (2) Removing the end of the conductive porous substrate 200A from between the electrode conductor 280 and the support frame 290 (end removing step); The present invention comprises:

[0061] In the above-mentioned (1) stuffing member removal step, if the stuffing member 700 is made of metal and fixed by welding, the welded portion is removed with a grinder, chisel, or the like, and the stuffing member 700 is removed from the support body frame 290. Alternatively, if the stuffing member 700 is made of resin and fixed with an adhesive, caulking agent, or the like, it is removed with a solvent, or the like. In the end portion detaching step (2) above, the end portion of conductive porous substrate 200A is detached in a manner that does not cause damage such as bending, sharpening, or cutting conductive porous substrate 200A.

[0062] [(Re)attaching the end of the conductive porous substrate] The end of the conductive porous substrate 200A can be (re)attached by, for example, (1) Inserting an end of the conductive porous substrate 200A into (the gap between) the support frame 290 and the electrode conductor 280 (end insertion step); (2) Further inserting the filler member 700 into the gap of (1) (filler member inserting step); and (3) joining the filler member 700 to the support frame 290 (filler member joining step); The present invention comprises:

[0063] In the above end insertion process (1), the end of the conductive porous substrate 200A is inserted into the gap between the support frame 290 and the electrode conductor 280, taking care not to damage the conductive porous substrate 200A by bending, sharpening, cutting, or the like. In the above-mentioned (2) stuffing member insertion step, a stuffing member 700 is further inserted into the gap between the support frame 290 and the electrode conductor 280. As a result, the end of the conductive porous substrate 200A is clamped and fixed between the electrode conductor 280 and the stuffing member 700. In the above-mentioned (3) stuffing member joining step, the stuffing member 700 is joined to the support frame 290. This allows the end of the conductive porous substrate 200A to be more reliably fixed between the electrode conductor 280 and the support frame 290. For example, the attachment method may be welding when the stuffing member 700 is made of metal, or adhesion with an adhesive or caulking agent when the stuffing member 700 is made of resin. In the case of joining by welding, the stuffing member 700 is not welded to the conductive porous substrate 200A from the viewpoint of reducing damage to the conductive porous substrate 200A. Here, the stuffing member 700 may be locally joined to the support frame 290 from the viewpoint of ease of removal and reattachment of the conductive porous substrate 200A. The means for fixing the ends of the conductive porous substrate 200A does not have to include (3), but is preferable from the viewpoint of more reliably fixing the ends of the conductive porous substrate 200A to the support frame 290.

[0064] [End of conductive porous substrate] As described above, the electrolytic cell of this embodiment has the characteristic feature that "the end of the conductive porous substrate 200A extends between the electrode conductor 280 and the support frame 290 in a cross-sectional view, and a filler member 700 is provided between the electrode conductor 280 and the support frame 290," but the end of the conductive porous substrate 200A can have an aspect where "it does not have a bending point in a cross-sectional view, but is curved overall."

[0065] 5 to 7, the end of the conductive porous substrate 200A can extend between the electrode conductor 280 and the support frame 290 so as not to have any bending points (bending points, turning points) in cross-sectional view. In other words, while the end of the conductive porous substrate 200A is positioned between the electrode conductor 280 and the support frame 290, the end can have a shape in which the end is continuously and gently curved as a whole and is not bent halfway (hereinafter, such a shape will also be referred to as "bending of the end").

[0066] When the end of conductive porous substrate 200A is bent, the end is continuously and gently curved as a whole, so that even if another member (e.g., diaphragm 300) comes into contact with conductive porous substrate 200A in the electrolytic cell, it is unlikely to be damaged. More specifically, even in a case where damage is usually likely to occur (as shown in FIG. 4, when flexible cathode 200A is biased so as to be pressed toward rigid anode 200B in the electrolytic cell, and flexible cathode 200A, diaphragm 300, and rigid anode 200B are strongly attached to each other), conductive porous substrate 200A does not have a relatively large displacement such as a bending point in cross section, so that diaphragm 300 is unlikely to be damaged by conductive porous substrate 200A. Thus, bending the end contributes to the reuse of other members.

[0067] Furthermore, when the end of the conductive porous substrate 200A is bent, the end edge is arranged so as to face the opposite direction (opposite side) to the direction in which the diaphragm 300 is arranged, as shown in Figures 5 to 7. This positions the end edge away from the diaphragm 300, thereby preventing damage to the diaphragm 300 due to contact with the end of the conductive porous substrate 200A. Therefore, bending the end contributes to the reuse of other members.

[0068] Another embodiment (second embodiment) will be described. This embodiment differs from the above-described embodiment (first embodiment) in that the support frame 290A has a chamfered portion 270. This difference will be described. 9 is a partial enlarged view of a characteristic portion. The support frame 290A has a chamfered portion 270 at a portion facing the edge of the electrode conductor 280, and a stuffing member 700 is disposed in the chamfered portion 270. Both ends of the chamfered portion 270 are curved (R-shaped) in cross-sectional view. The width W2 between the edge of the electrode conductor 280 and the opposing support frame 290A is smaller than the width W (see FIG. 7) in the absence of the chamfered portion 270. That is, in the second embodiment, the filler member 700 can be disposed closer to the outer edge of the support frame 290A in a plan view than in the absence of the chamfered portion 270 on the support frame 290A. This makes it possible to increase the area of ​​the electrode 200A that functions as an electrolytic cell.

[0069] The width of the filler member 700 may be larger than the width W2 of the gap between the electrode conductor 280 and the support frame 290A (the width between the edge of the electrode conductor 280 and the opposing support frame 290A), as shown in FIG.

[0070] Further, still another embodiment (third embodiment) will be described. This embodiment is different from the above-mentioned embodiment (first embodiment) in that the conductive porous substrate 200A is composed of two or more sub-porous substrates 200a, 200b. This difference will be described. FIG. 10 is a perspective view of a portion in which the conductive porous substrate 200A extends through the gap between the electrode conductor 280 and the support frame 290 in a cross-sectional view, and a filler is provided between the electrode conductor 280 and the support frame 290. The conductive porous substrate 200A is composed of two sub-porous substrates 200a and 200b. The two sub-porous substrates 200a and 200b can be configured as a single conductive porous substrate 200A by partially overlapping each other. Therefore, even if the conductive porous substrate 200A is damaged, only the damaged sub-porous substrate (for example, one of the sub-porous substrates 200a and 200b) of the two sub-porous substrates 200a and 200b needs to be partially replaced, which is more cost-effective than a conductive porous substrate 200A made of a single sheet.

[0071] From the viewpoint of facilitating the attachment and detachment (removal and installation) of the sub-porous substrates 200a, 200b, it is preferable to provide the packing members 700a, 700b corresponding to each of the sub-porous substrates 200a, 200b, as shown in FIG. 10. More specifically, the packing member 700a corresponds to the sub-porous substrate 200a and fixes the sub-porous substrate 200a. The packing member 700b corresponds to the sub-porous substrate 200b and fixes the sub-porous substrate 200b. In this case, when only the sub-porous substrate 200a is to be removed, the packing member 700a is removed from the support frame 290, but it is not necessary to remove the packing member 700b. Since the sub-porous substrates 200a, 200b are fixed by the corresponding packing members 700a, 700b, the attachment and detachment of the sub-porous substrates 200a, 200b is facilitated.

[0072] Further, still another embodiment (fourth embodiment) will be described. This embodiment differs from the above-described embodiment (first embodiment) in that the end of the electrode conductor 280A is curved. This difference will be described. FIG. 11 is an enlarged cross-sectional view of an electrolytic cell according to the fourth embodiment. The end of the electrode conductor 280A has a second curved portion 240 that is curved as a whole without having a bending point in cross-sectional view, and the second curved portion 240 faces the support frame 290. The conductive porous substrate 200A is not easily damaged because it contacts the part of the electrode conductor 280A that does not have a protrusion, that is, the curved portion 240 that is curved as a whole and a part of the flat upper surface. Therefore, in the electrolytic cell according to this embodiment, damage to the conductive porous substrate 200A due to contact with the electrode conductor 280A can be effectively suppressed. This embodiment also contributes to the reuse of the conductive porous substrate 200A. In addition, in this embodiment, the end of the electrode conductor 280A is curved, which prevents sagging and improves workability.

[0073] Because the end of the electrode conductor 280A is curved in the opposite direction to the side on which the diaphragm 300 is disposed, the diaphragm 300 is also less likely to be damaged by the electrode conductor 280A. Thus, in the electrolytic cell according to this embodiment, damage to the diaphragm 300 by the electrode conductor 280A can be effectively suppressed. This embodiment also contributes to the reuse of the diaphragm 300.

[0074] The filling member 700 is positioned between the end of the electrode conductor 280A (more specifically, a portion of its curved portion and / or upper surface) and the opposing support frame 290, and secures the end of the conductive porous substrate 200A.

[0075] Although the embodiments of the present invention have been described above, they 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 that various modifications can be made without departing from the spirit of the present invention.

[0076] For example, in the above embodiment, an electrolytic cell in which one electrode is a cathode and the other electrode is an anode has been described as an example, but the present invention is not limited to this. An electrolytic cell in which one electrode is an anode and the other electrode is a cathode may also be used.

[0077] In the first embodiment, as shown in Fig. 7, the stuffing member 700 does not protrude from the surface level of the support frame 290 and the electrode conductor 280 in a cross-sectional view, but this is not limited to this. For example, as shown in Fig. 15, the stuffing member 700 may protrude from the surface level. For example, the protruding height h of the stuffing member 700 from the surface level may be less than the thickness H of the gasket 260 (particularly the thickness when compressed), and in such a case, damage to the diaphragm (ion exchange membrane) 300 is more likely to be reduced. In Fig. 15, the protruding height h of the stuffing member 700 is about 1 / 2 the thickness H of the gasket 260.

[0078] In the second embodiment, the support frame 290A has a chamfered portion 270 at a portion facing the edge of the electrode conductor 280, but is not limited to this. For example, as shown in Fig. 12, the support frame 290A has a first curved portion 250 at the facing portion. The first curved portion 250 is curved as a whole without having a bending point in a cross-sectional view. A stuffing member 700 is placed in the first curved portion 250.

[0079] In the third embodiment, the plurality of sub-porous substrates are two sub-porous substrates 200a and 200b, but the present invention is not limited to this. The plurality of sub-porous substrates may be three or more sub-porous substrates.

[0080] In the third embodiment, the two sub-porous substrates 200a and 200b are arranged to overlap each other to form a single conductive porous substrate 200A, but the present invention is not limited to this. For example, the two sub-porous substrates 200a and 200b may be arranged adjacent to each other without a gap to form a single conductive porous substrate 200A, or the conductive porous substrate 200A may be arranged with their ends spaced apart from each other.

[0081] Furthermore, the second to fourth embodiments may be combined. An electrolytic cell according to a combination of the second and fourth embodiments may be, for example, as shown in FIG. 13. More specifically, the support frame 290A has a chamfered portion 270 at a portion facing the electrode conductor 280A, and a filler member 700 is disposed in the chamfered portion 270. Furthermore, the end of the electrode conductor 280A has a second curved portion 240 that is curved as a whole without having a bending point in a cross-sectional view, and the second curved portion 240 faces the chamfered portion 270 of the support frame 290A. In this embodiment, neither the support frame 290A nor the electrode conductor 280A has a protruding shape, so that damage to the conductive porous substrate 200A and the diaphragm 300 can be further suppressed.

[0082] An electrolytic cell according to a combination of the second and fourth embodiments may be, for example, as shown in Fig. 14. More specifically, the support frame 290A has a first curved portion 250 at a portion facing the electrode conductor 280A, and a stuffing member 700 is disposed in the first curved portion 250. Furthermore, the end of the electrode conductor 280A has a second curved portion 240 that is curved as a whole without having a bending point in a cross-sectional view, and the second curved portion 240 faces the first curved portion 250 of the support frame 290A. In this embodiment, both the support frame 290A and the electrode conductor 280A have curved portions, so that damage to the conductive porous substrate 200A and the diaphragm 300 can be further suppressed. [Explanation of symbols]

[0083] 100 Electrolyzer Unit 100' Electrolyzer Unit 100” Electrolyzer Unit 200A cathode (conductive porous base material) 200B Anode 200a, 200b Sub-porous substrate 240 Second curved section 250 First curve 260 Gasket 270 Chamfered part 280, 280A Electrode conductor (e.g., cathode base) 290,290A Support frame 300 Diaphragm (e.g., ion exchange membrane) 400 Conductive elastic body 450 Elastic part 700, 700a, 700b Filling material H Gasket thickness h Protruding height of filling material

Claims

1. An electrolytic cell comprising an anode, a cathode, a diaphragm, and a support frame, one of the anode and the cathode has an electrode conductor and a flexible conductive porous substrate disposed on the electrode conductor; the conductive porous substrate extends such that an end portion of the conductive porous substrate passes between the electrode conductor and the support frame in a cross-sectional view; an electrolytic cell comprising a filling member provided to fill a gap between an edge of the electrode conductor and the support frame facing the edge.

2. 2. The electrolytic cell of claim 1, wherein the end of the conductive porous substrate is secured between the electrode conductor and the support frame by the stuffing.

3. In cross section, a gasket between the support frame and the diaphragm, the protruding height of the stuffing from the surface level of the support frame and the electrode conductor being less than the thickness of the gasket; or 3. An electrolytic cell according to claim 1 or 2, wherein the filler does not protrude above the surface level.

4. 4. An electrolytic cell according to any one of claims 1 to 3, wherein the stuffing is attached to the support frame.

5. 5. The electrolytic cell of claim 4, wherein the stuffing is locally bonded to the support frame.

6. 6. The electrolytic cell according to claim 1, wherein the support frame has a chamfered portion or a first curved portion at a portion facing the electrode conductor, and the filler member is disposed at the chamfered portion or the first curved portion.

7. An electrolytic cell described in any one of claims 1 to 6, wherein, in a cross-sectional view, an end of the conductive porous substrate is clamped between the electrode conductor and the filler member.

8. 8. The electrolytic cell according to claim 1, wherein the filler member is made of metal.

9. 9. The electrolytic cell according to claim 1, wherein the end of the conductive porous substrate is curved as a whole without having a bending point in a cross-sectional view.

10. 10. The electrolytic cell according to claim 1, wherein the end of the electrode conductor has a second curved portion that is curved as a whole without having a bending point in a cross-sectional view, and the second curved portion faces the support frame.

11. 11. The electrolytic cell according to any one of claims 1 to 10, wherein the conductive porous substrate is composed of two or more sub-porous substrates.

12. 12. The electrolytic cell according to claim 1, wherein a conductive elastic body is provided on a back side of the conductive porous substrate of one of the electrodes such that the conductive elastic body presses the conductive porous substrate against the other electrode.

13. Electrolytic cell according to any one of claims 1 to 12, wherein the diaphragm is an ion exchange membrane.

14. The electrolytic cell according to any one of claims 1 to 13, which is for use in a zero-gap type salt electrolytic cell.

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