JP7669798B2 - Electrolyzer - Google Patents

Description

The present invention relates to an electrolytic cell. In particular, the present invention relates to an electrolytic cell that is at least composed of an anode, a cathode, a diaphragm, and a support frame.

Currently, electrolysis is used in a variety of 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 that perform electrolysis of an aqueous solution of sodium chloride 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.

International Publication (WO) 2012/091051 Patent No. 5108043 Patent No. 5970250 JP 2012-140652 A JP 2000-178781 A JP 2011-117047 A

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 method for salt electrolysis." It is also used in the electrolysis of alkaline solutions used in hydrogen production.

There are various types of electrolytic cells used in ion exchange membrane salt electrolysis, but the zero-gap type is the most common. In a zero-gap type electrolytic cell, the anode, diaphragm, and cathode are closely attached to each other to reduce the distance between the electrodes, thereby reducing the electrolyte resistance and power consumption. In a "zero-gap" type electrolytic cell, for example, one of the anode and cathode electrodes is provided with a relatively rigid electrode conductor and a relatively flexible conductive porous substrate placed on the electrode conductor, 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 with high rigidity when pressed by the deformation of an elastic body, while the other is structured so that it is highly rigid and has a rigid structure that does not deform much 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 electrode, the elastic force (i.e., reaction force) of the conductive elastic body can provide the pressure required for the electrode (e.g., anode) having rigidity, the diaphragm, and the conductive porous substrate (e.g., cathode) to come into close contact with each other.

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 issues. Specifically, they found the following problems:

In an electrolytic cell, when the components (e.g., electrodes) in the 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. When replacing the other electrode in the above-mentioned zero-gap electrolytic cell, in addition to removing the other electrode to be replaced, due to the structure, it may be necessary to remove one of the electrodes that is not to be replaced. For example, in order to correct the flatness of one electrode (e.g., anode) and perform electrolysis efficiently, it is necessary to remove the conductive porous substrate of the other electrode (e.g., cathode).

Because the conductive porous substrate is installed under 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 an effort to improve the performance of electrolytic cells for the purpose of saving energy, and as a result 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.

In addition, when the conductive porous substrate is fixed using a fluororesin pin, 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 fluororesin pin, the fluororesin pin 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 components (pin and ion exchange membrane). Therefore, there is also a need for fixing the conductive porous substrate to the electrolytic cell in a way that reduces damage to other components (e.g., diaphragm).

The present invention has been made in consideration of these problems. That is, the main object of the present invention is to provide an electrolytic cell that contributes to reuse (particularly, reuse of the conductive porous substrate).

The inventors of the present application attempted to solve the above problems by approaching them from a new perspective, rather than by simply extending the conventional technology. As a result, they came up with the invention of an electrolytic cell that achieves the above-mentioned main objective.

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 pad between the electrode conductor and the support frame.

Based on the present invention, it is possible to provide an electrolytic cell that is more useful for electrode replacement due to reuse.

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, it is easy to return the conductive porous substrate to its original state before attachment. Therefore, the conductive porous substrate can be reattached and used with minimal 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 components (e.g., diaphragm). Therefore, the present invention contributes to reuse.

FIG. 1 is a schematic diagram for illustrating the configuration of an electrolytic cell. FIG. 2 is a perspective view showing an example of a conductive elastic body used in an electrolytic cell. FIG. 3 is a schematic perspective view for explaining a combination of electrolytic cell units with a diaphragm interposed therebetween. FIG. 4 is a schematic horizontal cross-sectional view of an electrolytic cell according to an exemplary embodiment. 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. FIG. 6 is a schematic cross-sectional view for explaining an electrolytic cell provided as one embodiment (first embodiment) of the present invention. 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. FIG. 8 is a schematic diagram for illustrating a sharp end edge of a conductive porous substrate. FIG. 9 is an enlarged cross-sectional view for explaining 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. FIG. 10 is a perspective view for explaining a filler member provided between an electrode conductor and a support frame of an electrolytic cell according to still another embodiment (third embodiment) of the present invention. FIG. 11 is a schematic cross-sectional view for explaining an electrolytic cell according to still another embodiment (fourth embodiment) of the present invention. 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. FIG. 13 is a schematic cross-sectional view for explaining a modified example of an electrolytic cell provided as another embodiment (a combination of the second and fourth embodiments) of the present invention. 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). FIG. 15 is a diagram for explaining 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.

The electrolytic cell according to one embodiment of the present invention will be described in more detail below with reference to the drawings. The various elements in the drawings are shown merely as schematic and illustrative examples for the purpose of understanding the present invention, and the appearance and dimensional ratios may differ from the actual ones.

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 that includes at least an anode, a cathode, a diaphragm disposed 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.

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. More specifically, in the embodiment shown in FIG. 6, the direction along the planar direction of the electrolysis electrode corresponds to the left and right direction, and the direction perpendicular to the planar direction corresponds to the up and down direction. When the electrolysis cell is in operation, the electrolysis electrode in the embodiment shown in FIG. 6 is often used in an upright orientation as shown in FIG. 5. That is, the electrolysis electrode is often used by changing the orientation of the electrolysis electrode by approximately 90° from the state shown in FIG. 6. Therefore, the orientation of the cell and its components may differ when the electrolysis cell is in use (particularly when the electrolysis cell is in operation with the units constituting the electrolysis cell combined) and when it is not in use, particularly when it is not in operation before the units constituting the electrolysis cell are combined.

The various numerical ranges mentioned in this specification are intended to include the lower and upper limits themselves. That is, for example, a numerical range such as 1 to 10 is interpreted as including the lower limit of "1" and the upper limit of "10."

First, the basic configuration of the electrolytic cell that is the premise of the present invention will be explained, and then the features of the present invention will be explained. In the following explanation, the electrodes for the electrolytic cell, i.e., the electrodes for electrolysis, will be referred to simply as "electrodes" or, more specifically, as "anodes" or "cathodes."

[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.

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 just one example, in electrolytic cells used in the soda industry, a cation exchange membrane may be used as the diaphragm.

The electrolytic cell may further be provided with a conductive elastic body. The conductive elastic body contributes to the passage of electricity between the electrodes due to its "conductivity," while at the same time exerting a pressing force on 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.

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 consisting 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 consisting 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 acts to apply a pressing force from one electrode toward the other electrode, thereby promoting the adhesion 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, allowing the electrolytic cell to function favorably as a so-called "zero gap" type.

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 portion 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 portion 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.

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 arranged 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 arranged on the electrode conductor 280 and has flexibility. The anode 200B has a rigid electrode conductor (anode base). 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, wire mesh such as plain weave mesh and twill weave mesh, or punched metal.

The electrode conductor 280, which can serve as 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 the zero-gap (particularly true zero-gap) type. Furthermore, based on the understanding 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, for example, when the flexible electrode is a flexible cathode. Furthermore, from the viewpoint of function and structure, the electrode conductor 280 is preferably a porous plate material that serves as a current collector.

In a preferred embodiment, both the anode and the cathode may have a 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. In other words, 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 a plain weave mesh. From the viewpoint of being able to exhibit corrosion resistance (or also called corrosion resistance), 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, 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.

The electrolytic cell is preferably a zero-gap type, and has characteristics suitable for such a zero-gap type. One of such characteristics is that the anode and cathode are characterized in terms of the so-called "hardness" and "softness" of the electrode material, such as the rigidity and flexibility. 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. In other words, this 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.

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 multiple electrolytic cell units, and each of the electrolytic cell units has large electrode main surfaces on both opposing sides. 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 sides of the electrolytic cell unit 100, while an anode 200B (e.g., an anode surface made of expanded metal) is provided on the other of the opposing sides. In an electrolytic cell, such electrolytic cell units are connected to each other in multiple layers 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' and the anode surface of the other electrolytic cell unit 100'' face each other. In this way, an electrolytic cell is constructed by combining multiple electrolytic cell units via the ion exchange membrane 300. Note that an electrolytic cell constructed from multiple 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 part and a cathode part on both opposing sides, but may be "monopolar type" electrolytic cell units having only an anode part and only a cathode part on both opposing sides. In such a case, an electrolytic cell can be constructed by combining electrolytic cell units having only an anode part and an electrolytic cell unit having only a cathode part so that they are alternately arranged via an ion exchange membrane.

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 is, the more likely it is that the effects of bending due to its own weight cannot be ignored, and the attachment to the electrode support 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 Figure 3, the main surface size of the anode surface and cathode surface is on the order of m rather than on the order of several cm. 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, ±0.5 mm to 1.0 mm for the above reasons, and 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 may appear flat macroscopically, but when viewed microscopically, it tends to have localized irregularities.

If 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, 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 be locally elastically deformed 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 and the reaction force of the conductive elastic body is large, the anode, the ion exchange membrane 300, and the cathode are appropriately adhered to each other, and undesirable phenomena such as uneven current distribution are unlikely to occur.

For further understanding of the electrolytic cell, FIG. 4 is shown. FIG. 4 corresponds to a vertical cross-sectional view of an exemplary 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, the flexible cathode 200A of the expanded metal, the diaphragm 300, and the rigid anode 200B of the expanded metal are stacked in that order, and the 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.

In the electrolytic cell, as shown in FIG. 6, a gasket 260 is placed on the support frame 290. The gasket 260 is placed so as to surround the electrode chamber in a plan view, thereby sealing the gap between the diaphragm 300 and the support frame 290 in a cross-sectional view, and prevents leakage of the electrolyte in the electrode chamber and/or the gas and electrolyte generated in the electrode chamber to the outside of the electrode chamber.

[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 Fig. 5, Fig. 6 and Fig. 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 electrodes are in close contact with each other.

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.

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.

The effects of the present invention will be described in detail. When 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, and the electrode conductor 280 and the support frame 290 have a filling member 700 between them, even when the conductive porous substrate 200A of one electrode is once removed to replace the other electrode, the conductive porous substrate 200A is likely to return the conductive porous substrate 200A to its original state. In particular, the conductive porous substrate 200A can be recovered in a state in which damage such as bending, sharpening, and cutting is reduced. 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.

In order to better understand 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 side. In this operation, in order not to 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 that was 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, during the reattachment process, the conductive porous substrate often becomes bent, sharp, cut, etc., resulting in a state in which the reattached conductive porous substrate is significantly different from the conductive porous substrate before removal. Therefore, in the past, it was not possible to reattach and use the conductive porous substrate (i.e., to reuse it). Conductive porous substrates that are damaged in this way, such as by being bent, sharp, or cut, are difficult to repair (as described below), and efficient electrolysis in the electrolytic cell could not be achieved.

Furthermore, it was very difficult to repair a conductive porous substrate that was damaged by breakage, sharpness, or cutting because it was fine (fine mesh). For this reason, in conventional electrolytic cells, even if the conductive porous substrate itself had not reached the end of its life, it was necessary to replace it with a new conductive porous substrate when replacing the anode. Therefore, the inventors of the present invention have studied the manner of attachment of the conductive porous substrate 200A as a result of intensive research, and have found that if the removed conductive porous substrate 200A can be restored to a certain degree to its state before attachment, it can be reused. Based on this knowledge, the inventors of the present invention 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 filling 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, resulting in greater cost savings.

The ends of the conductive porous substrate 200A are preferably sandwiched and attached between the electrode conductor 280 and the support frame 290. The ends are not bonded to the support frame 290 and the electrode conductor 280, making them more easily "attachable and detachable."

As shown in FIG. 7, the length L from the point (contact point) at 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 portion 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 sufficient to at least secure the sandwiched portion, and there is no need to bend it to a portion corresponding to the length L. Since there is no need 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.

The conductive porous substrate 200A is also prone to sharpening, particularly at the 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 "ragged" 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 damaging 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 membrane 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 membrane 300) other than the conductive porous substrate 200A.

When the conductive porous substrate is damaged, such as broken, sharp, or cut, 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 or removed from the electrolytic cell, if the damaged portion comes into contact with other components (e.g., a diaphragm) in the electrolytic cell, damage to the other components may be caused. In the embodiment of the present invention, damage to the conductive porous substrate 200A, such as broken, sharp, or cut, is reduced, and therefore damage to other components in the electrolytic cell can be reduced. Therefore, the present invention also contributes to the reuse of other components other than the conductive porous substrate 200A.

(Aspects unique to the zero-gap system)
This embodiment is specific to a zero-gap electrolytic cell. As shown in Fig. 1, in a 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 in close contact. 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.

For example, if one of the anode and cathode used as the electrodes for electrolysis is relatively flexible compared 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 adhesion conditions, by having a 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 touch the ion exchange membrane 300, and damage to the ion exchange membrane 300 can be suppressed.

From a similar perspective, when the electrolytic cell is provided with the conductive elastic body 400, the anode 200B, the ion exchange membrane 300, and the cathode are more appropriately adhered to each other, but this usually means that the ion exchange membrane 300 is more likely to be 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 the conductive elastic body 400 presses the other electrode, suitable adhesion is obtained, but the ion exchange membrane 300 is more likely to be damaged (for example, when the cathode, particularly the cathode having a conductive porous substrate, is pressed against the anode 200B side through the ion exchange membrane 300, the conductive porous substrate 200A usually tends to damage 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 directly contact the ion exchange membrane 300, and damage to the ion exchange membrane 300 can be suppressed.

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 diaphragm damage is likely to be evident.

As described above, when the conductive porous substrate 200A is porous or open, the end edge of the conductive porous substrate 200A is particularly likely to become sharp. However, in the present invention, 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 the conductive porous substrate 200A has a filler member 700 between the electrode conductor 280 and the support frame 290, thereby suppressing the effect of the sharp edge. In other words, since one of the electrodes used in the electrolytic cell has the conductive porous substrate 200A, the present invention It can be said that the secondary effect of is easily manifested. More specifically, when at least one of the anode and cathode electrolysis electrodes 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 end of such a mesh opening electrode passes between the electrode conductor 280 and the support frame 290 in a cross-sectional view, the conductive porous substrate 200A extends, and a stuffing member 700 is provided between the electrode conductor 280 and the support frame 290, the effect of suppressing damage to the diaphragm is easily manifested.

[Filling material]
As shown in FIGS. 5-7, the electrolytic cell of the present invention includes a padding 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.

The stuffing member 700 has an elongated shape. Examples of elongated cross sections include substantially circular and substantially polygonal cross sections. Of 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 it is less likely to receive excessive external force locally from the stuffing member 700, and damage is reduced, which contributes to reuse.

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 securely 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 caulking agent, etc. For example, if the stuffing member 700 is made of metal, it is removed with a grinder or chisel, etc., and attached to the support frame 290 by welding (more specifically, tungsten-inert gas (TIG) welding, spot welding, etc.). If the stuffing member 700 is made of resin, it is removed with a solvent, etc., and attached to the support frame 290 with an adhesive or caulking agent, etc. Because the end of the conductive porous substrate 200A is fixed by the packing member 700 in this way, the end of the conductive porous substrate 200A can be easily removed and reattached using the packing member 700 when replacing the electrode.

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, as shown in FIG. 7. 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. Note that when the cross section of the stuffing member 700 is approximately circular, the width of the stuffing member 700 corresponds approximately to the diameter of the circle.

Also, as shown in FIG. 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 arranged above the same plane including the upper surface of the support frame 290 and the upper surface of the electrode conductor 280 without protruding. Therefore, as shown in FIG. 4, when the flexible cathode 200A is urged 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.

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 simply 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 may be, for example, a spot joint. In this regard, the local joining can be achieved, for example, by using 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 simply cutting only the joint.

Examples of materials for the filling member 700 include resins and metals. The resin for the filling member 700 is at least one selected from the group consisting of, for example, fluororesin, epoxy resin, UV epoxy resin, unsaturated polyester resin, polyamide resin, epoxy resin, phenolic 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 phenolic resin, and acrylic resin. Among these resins, fluororesin is preferred from the viewpoint of excellent corrosion resistance. The fluororesin is, for example, 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 polytetrafluoroethylene chloride (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. In other words, 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.

The electrode conductor (cathode base) 280 is a conductive member and usually has higher rigidity than the conductive porous substrate 200A. In the electrolytic cell, the 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 arranged so as to be sandwiched between the conductive porous substrate 200A and the anode 200B.

As described above, the present invention is characterized in 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. The present invention can be realized in various forms, which will be described below.

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 when replacing the electrodes is described below.

[Removal of 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 removing 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:

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 the conductive porous substrate 200A is detached in a manner that does not cause damage such as bending, sharpening, or cutting the conductive porous substrate 200A.

[(Re)attachment of 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:

In the above end insertion step (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 end of the conductive porous substrate 200A does not have to include (3), but is preferable from the viewpoint of more securely fixing the end of the conductive porous substrate 200A to the support frame 290.

[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."

As shown in Figures 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, inflections) in cross-sectional view. In other words, the end of the conductive porous substrate 200A can be positioned between the electrode conductor 280 and the support frame 290, but 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 is also referred to as "bending of the end").

When the end of the conductive porous substrate 200A is bent, the end is continuously and gently curved as a whole, so that even if another member (e.g., the diaphragm 300) comes into contact with the conductive porous substrate 200A in the electrolytic cell, the conductive porous substrate 200A is unlikely to be damaged. More specifically, even in a case where damage is usually likely to occur (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 strongly attached to each other), the conductive porous substrate 200A does not have a relatively large displacement such as a bending point in cross section, so that the diaphragm 300 is unlikely to be damaged by the conductive porous substrate 200A. Therefore, bending the end contributes to the reuse of other members.

Furthermore, when the end of the conductive porous substrate 200A is bent, the end edge is arranged to face in 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 components.

Another embodiment (second embodiment) will be described. This embodiment differs from the above-described embodiment (first embodiment) in that a 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 section.
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. In other words, in the second embodiment, the stuffing 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.

The width of the filler member 700 may be greater 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. 9.

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.
10 is a perspective view of a portion in which 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 and has a filler 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 one 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) of the two sub-porous substrates 200a and 200b needs to be partially replaced, which is more cost-effective than the conductive porous substrate 200A made of a single sheet.

From the viewpoint of facilitating the attachment and detachment (removal and installation) of the sub-porous substrates 200a and 200b, it is preferable to make the packing members 700a and 700b correspond to each of the multiple sub-porous substrates 200a and 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 there is no need to remove the packing member 700b. In this way, since the sub-porous substrates 200a and 200b are fixed by their corresponding packing members 700a and 700b, the attachment and detachment of the sub-porous substrates 200a and 200b becomes easier.

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 non-protruding portion of the electrode conductor 280A, 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. In this embodiment, the conductive porous substrate 200A can also be reused. In addition, in this embodiment, the end of the electrode conductor 280A is curved, which prevents sagging and improves workability.

The end of the electrode conductor 280A is curved in the opposite direction to the side where the diaphragm 300 is placed, so the diaphragm 300 is also less likely to be damaged by the electrode conductor 280A. Therefore, 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.

The filling member 700 is disposed between the end of the electrode conductor 280A (more specifically, the curved portion and/or part of the upper surface) and the opposing support frame 290, and fixes the end of the conductive porous substrate 200A.

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.

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.

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), in which 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.

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 filling member 700 is placed in the first curved portion 250.

In addition, in the third embodiment, two sub-porous substrates 200a and 200b are given as the multiple sub-porous substrates, but this is not limited thereto. The multiple sub-porous substrates may be three or more sub-porous substrates.

In the third embodiment, the two sub-porous substrates 200a and 200b are configured to partially overlap each other to form a single conductive porous substrate 200A, but this is not limited to the above. For example, the two sub-porous substrates 200a and 200b may be adjacent to each other without any gaps to form a single conductive porous substrate 200A, or the conductive porous substrate 200A may be configured with their ends spaced apart from each other.

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, the embodiment 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 stuffing 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, since neither the support frame 290A nor the electrode conductor 280A has a protruding shape, damage to the conductive porous substrate 200A and the diaphragm 300 can be further suppressed.

The electrolytic cell according to the 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, since both the support frame 290A and the electrode conductor 280A have curved portions, damage to the conductive porous substrate 200A and the diaphragm 300 can be further suppressed.

100 Electrolytic cell unit 100' Electrolytic cell unit 100" Electrolytic cell unit 200A Cathode (conductive porous substrate)
200B Anode 200a, 200b Sub-porous substrate 240 Second curved portion 250 First curved portion 260 Gasket 270 Chamfered portion 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 portion 700, 700a, 700b: Filling member H: Thickness of gasket h: Protruding height of filling member

Claims (14)

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 . The electrolytic cell according to claim 1, wherein the end of the conductive porous substrate is fixed between the electrode conductor and the support frame by the stuffing member. In cross section,
3. The electrolytic cell according to claim 1, further comprising 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 a thickness of the gasket, or the stuffing does not protrude from the surface level. The electrolytic cell according to any one of claims 1 to 3, wherein the filler member is attached to the support frame. The electrolytic cell according to claim 4, in which the filler member is locally joined to the support frame. The electrolytic cell according to any one of claims 1 to 5, wherein the support frame has a chamfered portion or a first curved portion in a portion facing the electrode conductor, and the filler member is disposed in the chamfered portion or the first curved portion. 7. The electrolytic cell according to claim 1, wherein, in a cross-sectional view, an end of the conductive porous substrate is sandwiched between the electrode conductor and the stuffing member. The electrolytic cell according to any one of claims 1 to 7, wherein the packing member is made of metal. The electrolytic cell according to any one of claims 1 to 8, wherein the end of the conductive porous substrate is curved overall without having any bending points in cross-sectional view. The electrolytic cell according to any one of claims 1 to 9, 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. 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. The electrolytic cell according to any one of claims 1 to 11, in which a conductive elastic body is provided on the back side of the conductive porous substrate so that the conductive porous substrate of one electrode is pressed against the other electrode by the conductive elastic body. The electrolytic cell according to any one of claims 1 to 12, wherein the diaphragm is an ion exchange membrane. 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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