Method and apparatus for manufacturing electrode for water electrolysis

Abstract

To provide a method for producing an electrode for water electrolysis, which is advantageous from the viewpoint of producing an electrode for water electrolysis having little variation in a state related to electrode performance.SOLUTION: The method for producing an electrode for water electrolysis includes the following (I) and (II). (I) A L1 for forming electrodes for water electrolysis on at least one conductive substrate 21 is circulated through a vessel 11 in which at least one conductive substrate 21 is disposed. (II) The flow direction of the L1 of the stock solution in the vessel 11 is reversed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method and an apparatus for producing electrodes for water electrolysis. [Background technology]

[0002] BACKGROUND OF THE INVENTION Techniques for flowing a liquid over a predetermined article for plating or cleaning are known in the art.

[0003] For example, Patent Document 1 describes an electroless plating method. This electroless plating method includes a cassette insertion step and a plating layer formation step. In the cassette insertion step, a cassette containing multiple thin flat plates arranged in parallel at appropriate intervals is inserted into a plating tank so that the flat plates are perpendicular to the surface of the chemical solution. In the plating layer formation step, the flow of the chemical solution supplied from the piping into the plating tank is rectified by passing the chemical solution through the opening of a predetermined rectification means, and the cassette is immersed in the chemical solution to form a plating layer on the flat plates.

[0004] Patent Document 2 describes a cleaning tank. In this cleaning tank, a cleaning liquid supply chamber is provided on one side of the tank body, and a cleaning liquid drain chamber is provided on the other side of the tank body. The object to be cleaned is accommodated in the tank body. This cleaning tank is controlled so that the liquid pressure in the liquid supply chamber and the liquid drain chamber are approximately constant.

[0005] Patent Document 3 describes a chemical plating tank. This chemical plating tank includes a plating tank, an overflow chamber, a plating solution discharge pipe, a perforated straightening plate, an air discharge pipe, a circulation pipe, a circulation pump, a filter, and an air pump. The perforated straightening plate has many plating solution flow holes to ensure uniform flow rate and dispersion of the plating solution. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-42832 [Patent Document 2] Japanese Patent Application Publication No. 10-144645 [Patent Document 3] Japanese Patent Application Publication No. 6-179976 Summary of the Invention [Problem to be solved by the invention]

[0007] The techniques described in the above patent documents need to be reconsidered from the viewpoint of producing water electrolysis electrodes with reduced variability in conditions related to electrode performance. Therefore, the present disclosure provides a method for producing water electrolysis electrodes that is advantageous from the viewpoint of producing water electrolysis electrodes with reduced variability in conditions related to electrode performance. [Means for solving the problem]

[0008] The present disclosure provides: circulating a raw material solution for forming water electrolysis electrodes on at least one conductive substrate through a container in which the at least one conductive substrate is disposed; and reversing the flow direction of the raw material solution inside the container. A method for producing an electrode for water electrolysis is provided. [Effects of the Invention]

[0009] The method for producing an electrode for water electrolysis according to the present disclosure is advantageous from the viewpoint of producing an electrode for water electrolysis with little variation in conditions related to electrode performance. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a plan view schematically illustrating an example of an apparatus for manufacturing electrodes for water electrolysis according to an embodiment. [Figure 2] FIG. 2 is a side view schematically illustrating an example of an apparatus for manufacturing electrodes for water electrolysis according to an embodiment. [Figure 3] FIG. 3 is a plan view schematically showing the arrangement of conductive substrates in the manufacturing apparatus shown in FIG. [Figure 4]FIG. 4 is a flowchart showing an example of a method for producing electrodes for water electrolysis according to an embodiment. [Figure 5] FIG. 5 is a diagram schematically illustrating another example of an apparatus for manufacturing electrodes for water electrolysis according to an embodiment. [Figure 6] FIG. 6 is a diagram schematically illustrating yet another example of an apparatus for manufacturing electrodes for water electrolysis according to an embodiment.

[0011] (Findings that formed the basis of this disclosure) In recent years, hydrogen has been attracting attention as a clean alternative energy source to fossil fuels due to environmental issues such as global warming and energy issues such as the depletion of oil resources. When hydrogen is burned, it basically only produces water. As a result, it does not emit carbon dioxide, which causes global warming, nor nitrogen oxides. For this reason, hydrogen is expected to be a clean energy source. Furthermore, there is a demand for green hydrogen, which is produced by electrolysis of water, rather than gray hydrogen, which is produced using fossil fuels as a raw material.

[0012] Fuel cells are an example of a device that uses hydrogen as a fuel with high efficiency. Fuel cells are being developed and widely used for automotive power sources and home power generation. In the coming hydrogen society, it is expected that hydrogen production will be able to produce clean hydrogen at low cost in order to ensure a stable supply.

[0013] Therefore, it is desirable to increase the amount of hydrogen produced per water electrolysis electrode. For example, a process has been studied for producing a highly active water electrolysis electrode by immersing a substrate in a raw material solution to form a highly active layer on the surface of the substrate. According to the study by the present inventors, in order to improve the performance of the water electrolysis electrode, it is important to minimize the variation in the state related to the electrode performance in the water electrolysis electrode. For example, it is important to uniformly form a highly active layer on the surface of the substrate. Therefore, the present inventors hypothesized that if the substrate is immersed in a flow of the raw material solution, a highly active layer can be uniformly formed on the surface of the substrate, thereby reducing the variation in the state related to the electrode performance in the water electrolysis electrode.

[0014] For example, in the electroless plating method described in Patent Document 1, multiple thin plates are arranged parallel to each other at an appropriate interval and inserted into a plating tank perpendicular to the surface of the chemical solution. The sidewall of the plating tank is provided with a chemical solution supply port and a chemical solution drain port. The chemical solution is supplied into the plating tank from the chemical solution supply port by a pump, flows parallel to the thin plates, and drains from the chemical solution drain port. The chemical solution discharged from the chemical solution drain port is adjusted as required, and the chemical solution is again supplied into the plating tank from the chemical solution supply port by the pump. In other words, the chemical solution circulates within the plating tank. The techniques described in Patent Documents 1, 2, and 3 use a flow rectifying component. For example, Patent Document 1 includes a buffer plate to ensure a uniform laminar flow of the chemical solution from the chemical solution supply port to the chemical solution drain port.

[0015] On the other hand, according to the inventors' studies, when reacting a substrate and a raw solution inside a container, it is extremely difficult to achieve a uniform laminar flow of the raw solution. There are several factors that can disrupt the flow of the raw solution, such as the difference in pressure between the supply inlet and the outlet of the raw solution, the container not being completely sealed, and components for placing the substrate inside the container. If the flow of the raw solution is a uniform laminar flow and the cross-sectional areas of the supply inlet and the outlet are the same, the average flow velocity of the raw solution passing through the substrate will be equal on the supply inlet side and the outlet side. However, if the flow of the raw solution is turbulent, the average flow velocity downstream of the raw solution flow may be lower than the average flow velocity upstream of the raw solution flow. This may result in differences in the average residence time of the raw solution between the upstream and downstream sides of the raw solution flow, which may cause variations in the amount of product produced on the substrate due to the reaction of the raw solution. As a result, a highly active layer may not be formed uniformly on the surface of the substrate.

[0016] Taking these circumstances into consideration, the present inventors conducted further studies and found that by causing the raw material solutions to flow in a predetermined manner, it is possible to reduce variations in the state of the electrodes for water electrolysis related to their performance. Based on this new finding, the present inventors have completed the method for producing the electrodes for water electrolysis according to the present disclosure.

[0017] (Embodiments of the present disclosure) Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. The embodiments described below are all comprehensive or specific examples. Therefore, the numerical values, shapes, materials, components, and the arrangement and connection of the components shown below are merely examples and do not limit the present disclosure unless otherwise stated in the claims. Furthermore, among the following components, components not described in the independent claims that represent the highest concept of this embodiment are described as optional components. Furthermore, in the drawings, descriptions of components with the same reference numerals may be omitted. To facilitate understanding of the drawings, each component is shown schematically, and the shape, dimensional ratio, and the like may not be accurately depicted. In the accompanying drawings, the X-axis, Y-axis, and Z-axis are perpendicular to each other, and the negative direction of the Z-axis is the direction of gravity.

[0018] (First embodiment) FIG. 1 is a plan view schematically illustrating an example of an apparatus for producing electrodes for water electrolysis according to an embodiment. FIG. 2 is a side view schematically illustrating an example of an apparatus for producing electrodes for water electrolysis according to an embodiment. As shown in FIGS. 1 and 2, the production apparatus 1a includes a container 11, a circulator 25, and a controller 30. In the production of electrodes for water electrolysis, at least one conductive substrate 21 is disposed in the container 11. The circulator 25 is a device for circulating a raw material solution L1, which is used to form a water electrolysis electrode on the at least one conductive substrate 21, through the container 11. The controller 30 controls the circulator 25 to reverse the flow direction of the raw material solution L1 within the container 11. As described above, the production apparatus 1a can provide a method for producing an electrode for water electrolysis, which includes the following (I) and (II). (I) A raw material solution L1 for forming water electrolysis electrodes on at least one conductive substrate 21 is circulated through a container 11 in which at least one conductive substrate 21 is placed. (II) The flow direction of the raw material solution L1 inside the container 11 is reversed.

[0019] As described above, in the production of water electrolysis electrodes, the flow direction of the raw solution L1 inside the container 11 is reversed, and the upstream and downstream flow of the raw solution L1 are therefore reversed. Therefore, the average residence time of the raw solution L1 is less likely to vary depending on the position on the conductive substrate 21, compared to when the flow direction of the raw solution L1 is not reversed. As a result, there is less variation in the amount of product produced on the conductive substrate 21 by the reaction of the raw solution L1, and water electrolysis electrodes with less variation in conditions related to electrode performance can be easily produced.

[0020] The conductive substrate 21 is not limited to a specific conductive substrate as long as it allows the production of a water electrolysis electrode. The conductive substrate 21 may contain, for example, a predetermined metal or a resin. The entire conductive substrate 21 may be made of metal. The conductive substrate 21 may have a configuration in which a metal-containing surface layer is formed on a resin member such as polypropylene or polyethylene. In this case, the metal-containing surface layer may be a plated film or a sputtered film. The metal contained in the conductive substrate 21 may be a pure metal such as nickel, or an alloy such as stainless steel or Inconel. Inconel is a registered trademark.

[0021] The surface of the conductive substrate 21 preferably contains at least one selected from the group consisting of nickel and nickel oxide. In this case, the conductive substrate 21 is likely to have high alkali resistance. When the surface of the conductive substrate 21 contains at least one selected from the group consisting of nickel and nickel oxide, the entire conductive substrate 21 may be made of nickel. The conductive substrate 21 may have a surface layer containing at least one selected from the group consisting of nickel and nickel oxide. The surface layer is, for example, a sputtered film or a plated film.

[0022] The shape of the conductive substrate 21 is not limited to a specific shape. The conductive substrate 21 is, for example, plate-shaped. The conductive substrate 21 may have a non-porous structure or a porous structure such as a mesh, foam, or nonwoven fabric. The conductive substrate 21 preferably has a porous structure. In this case, the surface area of ​​the conductive portion of the conductive substrate 21 tends to be large, and the water electrolysis electrode tends to have high electrode activity. In addition, it is easy to prevent gas generated during the water electrolysis reaction from escaping.

[0023] The thickness of the conductive substrate 21 is not limited to a specific value. The thickness of the conductive substrate 21 is, for example, 0.02 mm or more. In this case, the conductive substrate 21 tends to be easy to handle. The thickness of the conductive substrate 21 is, for example, 10 mm or less.

[0024] The raw material solution L1 is not limited to a specific solution as long as it can produce a water electrolysis electrode. The raw material solution L1 is, for example, a solution that can form a layer containing hydroxide on the conductive substrate 21. The raw material solution L1 may be, for example, a solution that can form a layer containing layered double hydroxide (LDH) on the conductive substrate 21. The raw material solution L1 may be prepared by adding iron(III) chloride and nickel(II) chloride to a predetermined solvent such as water, and optionally adding a chelating agent such as acetylacetone (ACAC).

[0025] 2, the circulator 25 includes, for example, a pump 23 and a pair of flow path switchers 24. The flow path switchers 24 are, for example, three-way valves.

[0026] The controller 30 is, for example, a programmable controller (PLC), and stores a program for controlling the pump 23 and the pair of flow path switchers 24.

[0027] As shown in FIGS. 1 and 2 , the manufacturing apparatus 1a has, for example, a first port 12 and a second port 13. The first port 12 and the second port 13 are arranged, for example, on opposite sides of a side wall of a container 11. A raw material solution L1 sent by operation of a pump 23 passes through one of a pair of flow path switchers 24 and one of the first port 12 and the second port 13, and is introduced into the container 11. Additionally, inside the container 11, the raw material solution L1 flows from one of the first port 12 and the second port 13 to the other of the first port 12 and the second port 13, and is introduced to the outside of the container 11. Inside the container 11, the raw material solution L1 flows, for example, in a direction perpendicular to the side wall of the container 11 (the X-axis direction). The raw material solution L1 discharged from the container 11 passes through the other of the pair of flow path switchers 24, and is again sent toward the container 11 by the pump 23.

[0028] The manufacturing apparatus 1a includes, for example, a first nozzle 16 and a second nozzle 17. The first nozzle 16 is connected to the first port 12. The second nozzle 17 is connected to the second port 13. The first nozzle 16 has a plurality of first openings 18, which are provided at predetermined intervals, for example, in a plane perpendicular to the X-axis. The sum of the opening areas of the plurality of first openings 18 is preferably the same as or close to the cross-sectional area of ​​the flow path formed by the first port 12, for example, 95% to 105% of the cross-sectional area. The second nozzle 17 has a plurality of second openings 19, which are provided at predetermined intervals, for example, in a plane perpendicular to the X-axis. The sum of the opening areas of the plurality of second openings 19 is preferably the same as or close to the cross-sectional area of ​​the flow path formed by the first port 12, for example, 95% to 105% of the cross-sectional area. In addition, the sum of the opening areas of the plurality of first openings 18 is desirably the same as or close to the sum of the opening areas of the plurality of second openings 19, for example, the sum of the opening areas of the plurality of first openings 18 is 95% to 105% of the sum of the opening areas of the plurality of second openings 19. The plurality of first openings 18 and the plurality of second openings 19 open in opposite directions to each other. A liquid level of the raw material solution L1 is formed in a direction perpendicular to the plane in which the plurality of first openings 18 are provided in the first nozzle 16 and the plane in which the plurality of second openings 19 are provided in the second nozzle 17.

[0029] As shown in FIG. 1, the manufacturing apparatus 1a includes, for example, a magazine 15. The magazine 15 is disposed inside the container 11 between a first nozzle 16 and a second nozzle 17. The magazine 15 is a member for supporting at least one conductive substrate 21 inside the container 11. FIG. 3 is a plan view schematically showing the arrangement of the conductive substrate 21 in the manufacturing apparatus 1a shown in FIG. 1. As shown in FIG. 3, the magazine 15 includes a bottom plate 15a and a pair of guides 15b. The pair of guides 15b are disposed at both ends of the magazine 15 in the X-axis direction. One of the pair of guides 15b is disposed near the first nozzle 16. The other of the pair of guides 15b is disposed near the second nozzle 17.

[0030] The guide 15b has a groove 15m, and the width of the groove 15m is greater than the thickness of the conductive substrate 21. The end of the conductive substrate 21 is received in this groove 15m, and the conductive substrate 21 is supported.

[0031] As shown in FIG. 1 , the production apparatus 1a further includes, for example, a flow path 14. The flow path 14 has a flow path cross-sectional area that changes in the flow direction (X-axis direction) of the raw solution L1 as the raw solution L1 flows over the conductive substrate. The circulator 25 generates a flow of the raw solution L1 such that the flow path cross-sectional area of ​​the flow path 14 downstream of the flow of the raw solution L1 is smaller than the flow path cross-sectional area of ​​the flow path 14 upstream of the flow of the raw solution L1. When the flow of the raw solution L1 is generated in this state, and the flow rate in the flow path 14 does not change, the average flow velocity of the raw solution L1 downstream may increase according to the fluid continuity equation. Therefore, even if the flow of the raw solution L1 is disturbed, the average flow velocity is unlikely to decrease downstream of the flow of the raw solution L1. Therefore, there is little variation in the amount of product produced on the conductive substrate 21 by the reaction of the raw solution. As a result, water electrolysis electrodes with little variation in conditions related to electrode performance can be easily produced. Furthermore, as described above, the flow direction of the raw material solution L1 inside the container 11 is reversed, so that it is possible to prevent the average flow velocity from continuing to decrease downstream of the flow of the raw material solution L1.

[0032] As described above, because the flow direction of the raw solution L1 inside the container 11 is reversed, the flow of the raw solution L1 does not necessarily have to occur in the above-described state throughout the entire period during which the water electrolysis electrode is produced. The production of the water electrolysis electrode may include a period during which the raw solution L1 flows in the above-described state. The production of the water electrolysis electrode may include a period during which the raw solution L1 flows in a state in which the cross-sectional area of ​​the flow path 14 downstream of the flow of the raw solution L1 is larger than the cross-sectional area of ​​the flow path 14 upstream of the flow of the raw solution L1.

[0033] The plurality of first openings 18 and the plurality of second openings 19 are arranged, for example, in a row in a direction perpendicular to the liquid surface of the raw solution L1 (Z-axis direction). For example, the distance from the first opening 18 or the second opening 19 to the conductive substrate 21 is substantially the same at multiple positions in the direction perpendicular to the liquid surface of the raw solution L1. This makes it difficult for the flow resistance from the first opening 18 or the second opening 19 to the conductive substrate 21 to vary in the Z-axis direction, and makes it easier to uniform the average flow velocity of the raw solution L1 on the upstream side in the flow channel 14.

[0034] The production apparatus 1a includes, for example, a plurality of rectifying plates 20. The plurality of rectifying plates 20 are disposed inside the container 11. In the production of a water electrolysis electrode, for example, a conductive substrate 21 is disposed between the plurality of adjacent rectifying plates 20. The adjacent plurality of rectifying plates 20 are disposed non-parallel when viewed in the flow direction (X-axis direction) of the raw solution L1. With this configuration, the plurality of rectifying plates 20 can generate a flow of the raw solution L1 in which the cross-sectional area of ​​the flow channel 14 downstream of the flow of the raw solution L1 is smaller than the cross-sectional area of ​​the flow channel 14 upstream of the flow of the raw solution L1.

[0035] The conductive base material 21 is disposed, for example, near the center of a space defined by a pair of adjacent current plates 20 .

[0036] A plurality of conductive substrates 21 may be arranged in the container 11. In this case, the manufacturing apparatus 1a includes, for example, a plurality of flow paths 14. Furthermore, the guide 15b has a plurality of grooves 15m, and a plurality of conductive substrates 21 can be arranged along the plurality of grooves 15m.

[0037] 3, in the manufacturing apparatus 1a, it is possible to arrange a plurality of adjacent conductive base materials 21 in parallel. With such a configuration, the work of arranging the plurality of conductive base materials 21 tends to be easy.

[0038] 1 , adjacent rectifier plates 20 are arranged non-parallel when viewed in the flow direction of the raw solution L1. In addition, adjacent rectifier plates 20 sandwiching a non-parallel arranged rectifier plate 20 are arranged parallel when viewed in the flow direction of the raw solution L1. This configuration makes it easy to reduce the volume required to form the multiple flow paths 14 inside the container 11, and tends to improve the productivity of water electrolysis electrodes.

[0039] 4 is a flowchart showing an example of a method for producing electrodes for water electrolysis according to an embodiment. First, in step S101, the conductive substrate 21 is placed inside the container 11. For example, the conductive substrate 21 is placed by inserting ends of the conductive substrate 21 into the grooves 15m of the pair of guides 15b of the magazine 15.

[0040] Next, in step S102, circulation of the raw solution L1 through the container 11 is initiated. For example, the controller 30 transmits a control signal to the pump 23 to operate the pump 23. As a result, the raw solution L1 passes through one of the pair of flow path switchers 24 and the first port 12, and is discharged from the first opening 18 of the first nozzle 16 toward the flow path 14. This causes a flow of the raw solution L1 in the positive direction of the X axis. The raw solution L1 passes through the flow path 14 while contacting the conductive substrate 21. As a result, a predetermined layer is formed on the conductive substrate 21 through a reaction involving the raw solution L1 and the conductive substrate 21. The raw solution L1 that has passed through the flow path 14 is sucked into the second opening 19 of the second nozzle 17 and discharged to the outside of the container 11 through the second port 13. Thereafter, the raw solution L1 passes through the other of the pair of flow path switchers 24 and is again sent toward the container 11 by the pump 23.

[0041] Next, the process proceeds to step S103, where it is determined whether a predetermined time has elapsed, and the process of step S102 is continued until the result of this determination becomes affirmative.

[0042] If the determination result in step S103 is affirmative, the process proceeds to step S104, where the flow direction of the raw solution L1 is reversed. In FIGS. 1 and 2, the solid arrows indicate the initial flow direction of the raw solution L1 before reversal, and the dashed arrows indicate the flow direction of the raw solution L1 when the flow direction of the raw solution L1 is first reversed. For example, the controller 30 transmits a control signal to the pair of flow path switchers 24, which switches the flow path so that the raw solution L1 discharged from the pump 23 is sent toward the second port 13. As a result, the raw solution L1 passes through one of the pair of flow path switchers 24 and the second port 13, and is discharged from the second opening 19 of the second nozzle 17 toward the flow path 14. This causes the raw solution L1 to flow in the negative direction of the X axis. As in step S102, a predetermined layer is formed on the conductive substrate 21. The raw solution L1 that has passed through the flow path 14 is sucked into the first opening 18 of the first nozzle 16 and discharged to the outside of the container 11 through the first port 12. Thereafter, the raw material solution L1 passes through the other of the pair of flow path switchers 24 and is sent by the pump 23 toward the container 11 again.

[0043] Next, the process proceeds to step S105, where a determination is made as to whether the formation of the water electrolysis electrodes is complete. For example, the controller 30 acquires data indicative of the state of the conductive substrate 21, and determines whether the formation of the water electrolysis electrodes is complete based on the data. Examples of the data indicative of the state of the conductive substrate 21 include image data and optical measurement data of the conductive substrate 21. A determination as to whether the formation of the water electrolysis electrodes is complete may also be made based on data indicative of the state of the raw material solution L1. Examples of the data indicative of the state of the raw material solution L1 include concentration data and optical measurement data of a specific component.

[0044] If the result of the determination in step S105 is negative, the process proceeds to step S108, where it is determined whether a predetermined time has elapsed, and if this determination is positive, the process proceeds to step S104, where the flow direction of the raw material solution L1 is reversed again. In this way, for example, the flow direction of the raw material solution L1 is reversed every time the predetermined time has elapsed.

[0045] If the result of the determination in step S105 is affirmative, the process proceeds to step S106, where the circulation of the raw material solution L1 is stopped. For example, the controller 30 sends a control signal to the pump 23 to stop the pump 23. Next, the process proceeds to step S107, where the water electrolysis electrodes are removed from the container 11, thereby completing the production of water electrolysis electrodes.

[0046] As shown in FIG. 1 , a conductive substrate 21 may be disposed in a flow path 14 in which the cross-sectional area of ​​the flow downstream of the raw solution L1 is larger than the cross-sectional area of ​​the flow upstream of the raw solution L1. In this case, the average flow velocity of the flow path 14 decreases toward the downstream of the flow of the raw solution L1. As described above, by reversing the flow direction of the raw solution L1 in step S104, the average flow velocity of the flow downstream of the raw solution L1 is greater than the average flow velocity of the flow upstream of the raw solution L1. Thus, at a certain point in time, there may be a mixture of flow paths 14 in which the cross-sectional area of ​​the flow downstream of the raw solution L1 is larger than the cross-sectional area of ​​the flow upstream of the raw solution L1, and flow paths 14 in which the cross-sectional area of ​​the flow downstream of the raw solution L1 is larger than the cross-sectional area of ​​the flow upstream of the raw solution L1. In this case, as described above, the flow direction of the raw solution L1 reverses after a predetermined time has elapsed. Therefore, in all of the multiple flow paths 14, there may be a period in which the average flow velocity of the flow downstream of the raw solution L1 is greater than the average flow velocity of the flow upstream of the raw solution L1.

[0047] For example, bubbles may accumulate in the groove 15m of the guide 15b downstream of the magazine 15, which corresponds to the flow path 14 where the average flow velocity of the raw solution L1 decreases downstream. The accumulated bubbles may bond together and grow larger, increasing in size over time. If such bubbles come into contact with the upper surface of the conductive substrate 21, a layer necessary for achieving electrode performance may not be sufficiently formed at the contact point of the bubbles. As described above, by reversing the flow of the raw solution L1, the accumulated bubbles downstream of the flow of the raw solution L1 are displaced. This can prevent the bubbles from growing or remaining in a specific location for a long period of time.

[0048] In the above-described manufacturing method, the flow direction of the raw solution L1 is reversed when a predetermined time has elapsed. Alternatively, whether or not to reverse the flow direction of the raw solution L1 may be determined based on the measurement results of the concentration of a specific component of the raw solution L1 inside the container 11. For example, the reversal of the flow direction of the raw solution L1 may be triggered when the difference between the maximum and minimum concentrations of the specific component at multiple locations inside the container 11 reaches a predetermined value or more. Additionally, the controller 30 may reverse the flow direction of the raw solution L1 when it receives a predetermined signal indicating an instruction from an operator. Alternatively, the flow direction of the raw solution L1 may be reversed by an operator manually operating the flow path switch 24.

[0049] The circulator 25 may be modified to include, for example, two pumps arranged in parallel so as to be able to pump out the raw solution L1 in opposite directions. In this case, the flow direction of the raw solution L1 can be reversed by switching which of the two pumps is operated. The circulator 25 may be modified to include, for example, a pump whose operation can be switched so as to pump out the raw solution L1 in the opposite direction. In this case, the flow direction of the raw solution L1 can be reversed by switching the operation of the pump. In this case, the flow path switcher 24 may be omitted from the manufacturing apparatus 1a.

[0050] In the above-described production method, multiple types of raw material solutions L1 may be used, or a predetermined additive may be added during the production of the water electrolysis electrode. An example of the additive is a pH-increasing agent. An example of the pH-increasing agent is propylene oxide (POX).

[0051] (Second embodiment) Fig. 5 is a schematic diagram illustrating another example of an apparatus for manufacturing electrodes for water electrolysis according to an embodiment. The manufacturing apparatus 1b shown in Fig. 5 has the same configuration as the manufacturing apparatus 1a, except for the parts that will be particularly described. The explanation for the first embodiment also applies to the second embodiment, unless there is a technical contradiction.

[0052] 5, in the manufacturing apparatus 1b, a plurality of conductive substrates 21 can be disposed inside the container 11. Adjacent conductive substrates 21 can be disposed non-parallel to each other.

[0053] According to the production apparatus 1b, the flow path 14 can be formed by a plurality of conductive substrates 21 that are adjacent to each other and not parallel to each other. This allows the flow of the raw solution L1 to be generated in a state in which the cross-sectional area of ​​the flow path 14 downstream of the flow of the raw solution L1 is smaller than the cross-sectional area of ​​the flow path 14 upstream of the flow of the raw solution L1. Therefore, even if the flow of the raw solution L1 is turbulent, the average flow velocity of the raw solution L1 is less likely to decrease downstream of the flow of the raw solution L1, and the amount of product produced on the conductive substrates 21 by the reaction of the raw solution L1 is less likely to vary. As a result, water electrolysis electrodes with reduced variation in conditions related to electrode performance can be easily produced.

[0054] According to the production apparatus 1b, the current plate 20 is not required to form the flow path 14, so the volume of the container 11 can be reduced, which tends to increase the productivity of water electrolysis electrodes.

[0055] A pair of guides 15b are provided at both ends of the magazine 15, and the guides 15b have grooves 15m, and the width of the grooves 15m is greater than the thickness of the conductive substrate 21. The ends of the conductive substrate 21 are received in the grooves 15m, and the conductive substrate 21 is supported.

[0056] The plurality of conductive substrates 21 may be arranged, for example, such that conductive substrates 21 belonging to a first group consisting of a plurality of conductive substrates 21 arranged parallel to one another and conductive substrates 21 belonging to a second group consisting of a plurality of conductive substrates 21 arranged parallel to one another are alternately arranged. When the plurality of conductive substrates 21 are viewed in the flow direction of the raw material solution L1, the conductive substrates 21 belonging to the first group and the conductive substrates 21 belonging to the second group may be arranged so as to be adjacent to one another but not parallel to one another.

[0057] (Third embodiment) Fig. 6 is a schematic diagram illustrating yet another example of an apparatus for manufacturing electrodes for water electrolysis according to an embodiment. The manufacturing apparatus 1c shown in Fig. 6 has the same configuration as the manufacturing apparatus 1a, except for the parts that will be particularly described. The explanation for the first embodiment also applies to the second embodiment, unless there is a technical contradiction.

[0058] 6, the production apparatus 1c does not include a flow straightening plate 20, and adjacent conductive substrates 21 can be arranged in parallel. In the production apparatus 1c, the cross-sectional area of ​​the flow path of the raw material solution L1 flowing on the conductive substrates 21 is constant in the flow direction of the raw material solution L1.

[0059] In the production apparatus 1c, the flow direction of the raw solution L1 is also reversed. Therefore, the average residence time of the raw solution L1 is less likely to vary depending on the position on the conductive substrate 21, compared to when the flow direction of the raw solution L1 is not reversed. As a result, there is less variation in the amount of product produced on the conductive substrate 21 by the reaction of the raw solution L1, and water electrolysis electrodes with less variation in conditions related to electrode performance can be produced. In addition, the production apparatus 1c does not require a rectifying plate 20 to form the flow path 14, so the volume of the container 11 can be reduced, and productivity of water electrolysis electrodes can be easily improved.

[0060] From the above description, many modifications and other embodiments of the present disclosure will be apparent to those skilled in the art. Therefore, the above description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode for carrying out the present disclosure. Details of the structure and / or function thereof can be substantially changed without departing from the spirit of the present disclosure.

[0061] (Addendum) From the above description, the following techniques are disclosed. (Technology 1) circulating a raw material solution for forming water electrolysis electrodes on at least one conductive substrate through a container in which the at least one conductive substrate is disposed; and reversing the flow direction of the raw material solution inside the container. Method for manufacturing electrodes for water electrolysis. (Technology 2) the raw material solution passes through at least one flow path having a flow path cross-sectional area that changes in a flow direction of the raw material solution when the raw material solution flows over the at least one conductive substrate; causing the flow of the raw solution in a state in which a cross-sectional area of ​​the at least one flow path downstream of the flow of the raw solution is smaller than a cross-sectional area of ​​the flow path upstream of the flow of the raw solution. A method for producing an electrode for water electrolysis according to the first aspect of the present invention. (Technology 3) The at least one conductive substrate is disposed between a plurality of adjacent current plates provided inside the container; the adjacent straightening plates are arranged non-parallel when viewed in the flow direction of the raw material solution; The method for producing the water electrolysis electrode according to the second aspect of the present invention. (Technology 4) the at least one conductive substrate is a plurality of the conductive substrates; The adjacent conductive substrates are arranged in parallel. A method for producing an electrode for water electrolysis according to claim 3. (Technology 5) the adjacent plurality of straightening plates are arranged non-parallel when viewed in the flow direction of the raw material solution, the plurality of straightening plates adjacent to each other across the non-parallel arranged straightening plate are arranged parallel to each other when viewed in the flow direction of the raw material solution; 10. A method for producing an electrode for water electrolysis according to claim 3 or 4. (Technology 6) the at least one conductive substrate is a plurality of the conductive substrates; disposing the plurality of conductive substrates inside the container; The adjacent conductive substrates are arranged non-parallel when viewed in the flow direction of the raw material solution. The method for producing the water electrolysis electrode according to the second aspect of the present invention. (Technology 7) a container in which at least one conductive substrate is disposed; a circulator for circulating a raw material solution for forming water electrolysis electrodes on the at least one conductive substrate through the container; and a controller that controls the circulator to reverse the flow direction of the raw material solution inside the container; Water electrolysis electrode manufacturing equipment. (Technology 8) a cross-sectional area of ​​a flow path of the raw material solution flowing on the at least one conductive substrate changes in a flow direction of the raw material solution; the circulator generates a flow of the raw solution in a state in which the cross-sectional area of ​​the flow path downstream of the flow of the raw solution is smaller than the cross-sectional area of ​​the flow path upstream of the flow of the raw solution. 10. The apparatus for manufacturing electrodes for water electrolysis according to claim 7. (Technology 9) A plurality of flow straightening plates are disposed inside the container, the at least one conductive substrate can be disposed between adjacent ones of the plurality of rectifying plates, the adjacent straightening plates are non-parallel when viewed in the flow direction of the raw material solution. 9. A manufacturing apparatus for electrodes for water electrolysis according to claim 8. (Technology 10) the at least one conductive substrate is a plurality of the conductive substrates; The adjacent conductive substrates can be arranged in parallel. The apparatus for manufacturing electrodes for water electrolysis according to the present invention. (Technology 11) the adjacent plurality of straightening plates are arranged non-parallel when viewed in the flow direction of the raw material solution, the plurality of straightening plates adjacent to each other with the straightening plate disposed non-parallel therebetween are disposed parallel to each other when viewed in the flow direction of the raw material solution; 11. The apparatus for manufacturing electrodes for water electrolysis according to claim 9 or 10. (Technology 12) the at least one conductive substrate is a plurality of the conductive substrates; The adjacent conductive substrates may be arranged non-parallel. 9. A manufacturing apparatus for electrodes for water electrolysis according to claim 8. [Industrial Applicability]

[0062] The present disclosure can be used to manufacture electrodes for water electrolysis. [Explanation of symbols]

[0063] 1a, 1b manufacturing equipment 11 Container 14 Flow path 20 Rectifier plate 21 Conductive substrate 25 Circulatory system 30 Controller L1 raw material solution

Claims

1. circulating a raw material solution for forming water electrolysis electrodes on at least one conductive substrate through a container in which the at least one conductive substrate is disposed; and reversing the flow direction of the raw material solution inside the container. A method for manufacturing an electrode for water electrolysis.

2. the raw material solution passes through at least one flow path having a flow path cross-sectional area that changes in a flow direction of the raw material solution when the raw material solution flows over the at least one conductive substrate; causing the flow of the raw solution in a state in which a cross-sectional area of ​​the at least one flow path downstream of the flow of the raw solution is smaller than a cross-sectional area of ​​the flow path upstream of the flow of the raw solution. The method for producing the water electrolysis electrode according to claim 1.

3. The at least one conductive substrate is disposed between a plurality of adjacent current plates provided inside the container; the adjacent straightening plates are arranged non-parallel when viewed in the flow direction of the raw material solution; The method for producing the water electrolysis electrode according to claim 2.

4. the at least one conductive substrate is a plurality of the conductive substrates; The adjacent conductive substrates are arranged in parallel. The method for producing the electrode for water electrolysis according to claim 3 .

5. the adjacent plurality of straightening plates are arranged non-parallel when viewed in the flow direction of the raw material solution, the plurality of straightening plates adjacent to each other across the non-parallel arranged straightening plate are arranged parallel to each other when viewed in the flow direction of the raw material solution; The method for producing the electrode for water electrolysis according to claim 3 .

6. the at least one conductive substrate is a plurality of the conductive substrates; disposing the plurality of conductive substrates inside the container; The adjacent conductive substrates are arranged non-parallel when viewed in the flow direction of the raw material solution. The method for producing the water electrolysis electrode according to claim 2.

7. a container in which at least one conductive substrate is disposed; a circulator for circulating a raw material solution for forming water electrolysis electrodes on the at least one conductive substrate through the container; and a controller that controls the circulator to reverse the flow direction of the raw material solution inside the container; Water electrolysis electrode manufacturing equipment.

8. a cross-sectional area of ​​a flow path of the raw material solution flowing on the at least one conductive substrate changes in a flow direction of the raw material solution; the circulator generates a flow of the raw solution in a state in which the cross-sectional area of ​​the flow path downstream of the flow of the raw solution is smaller than the cross-sectional area of ​​the flow path upstream of the flow of the raw solution. The apparatus for manufacturing the electrode for water electrolysis according to claim 7.

9. A plurality of flow straightening plates are disposed inside the container, the at least one conductive substrate can be disposed between adjacent ones of the plurality of current plates; the adjacent straightening plates are non-parallel when viewed in the flow direction of the raw material solution. The apparatus for manufacturing the electrode for water electrolysis according to claim 8.

10. the at least one conductive substrate is a plurality of the conductive substrates; The adjacent conductive substrates can be arranged in parallel. The apparatus for manufacturing the electrode for water electrolysis according to claim 9.

11. the adjacent plurality of straightening plates are arranged non-parallel when viewed in the flow direction of the raw material solution, the plurality of straightening plates adjacent to each other with the straightening plate disposed non-parallel therebetween are disposed parallel to each other when viewed in the flow direction of the raw material solution; The apparatus for manufacturing the electrode for water electrolysis according to claim 9.

12. the at least one conductive substrate is a plurality of the conductive substrates; The adjacent conductive substrates may be arranged non-parallel. The apparatus for manufacturing the electrode for water electrolysis according to claim 8.

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