Conductive components, fuel cells, and electrolytic devices

Abstract

To provide a fuel cell and an electrolytic device whose production cost can be reduced.SOLUTION: An electroconductive member 10 comprises a first layer 1 and a second layer 2. The first layer 1 is a porous body. The second layer 2 is laminated on the first layer 1. The first layer 1 is used as a current collector for a fuel cell 100 or an electrode for an electrolytic device 200. A porosity of the second layer 2 is lower than a porosity of the first layer 1. The porosity of the second layer 2 is 5% or less. The second layer 2 comprises a plurality of through holes.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a conductive member, a fuel cell, and an electrolysis device. This application claims priority based on Japanese Patent Application No. 2021-120929 filed on July 21, 2021. All the contents described in the Japanese patent application are incorporated herein by reference. [Background Art]

[0002] Conventionally, devices utilizing electrochemical reactions, such as fuel cells and electrolysis devices, are known. For example, Japanese Patent Laid-Open No. 2021-68493 discloses a fuel cell in which a current collector made of a metal mesh is laminated and arranged so as to be in contact with an electrode of a cell, and a separator having flow paths for an oxidant or fuel formed on the current collector is further laminated. In addition, Japanese Patent Laid-Open No. 2009-149932 discloses an electrolysis device in which electrode bodies are arranged so as to sandwich both sides of an ion-permeable diaphragm in an electrolytic cell. The electrode body includes a mesh-shaped electrode member and a mesh-shaped conductive member brazed to the mesh-shaped electrode member and having an uneven surface. [Prior Art Literature] [Patent Literature]

[0003] [Patent Literature 1] Japanese Patent Laid-Open No. 2021-68493 [Patent Literature 2] Japanese Patent Laid-Open No. 2009-149932 [Summary of the Invention]

[0004] The conductive member of the present disclosure includes a first layer and a second layer. In the first layer, a plurality of pores are dispersedly formed. The second layer is laminated on the first layer. The first layer and the second layer are used for a current collector for a fuel cell or an electrode for an electrolysis device. The porosity of the second layer is lower than the porosity of the first layer. The porosity of the second layer is 5% or less. [Brief Description of the Drawings]

[0005] [Figure 1] Figure 1 is a schematic cross-sectional view of a fuel cell according to Embodiment 1. [Figure 2] Figure 2 is a schematic partial cross-sectional view of the conductive members constituting the fuel cell shown in Figure 1. [Figure 3] Figure 3 is a partially enlarged schematic diagram of the first layer of the conductive member shown in Figure 2. [Figure 4] Figure 4 is an enlarged schematic diagram of region IV in Figure 3. [Figure 5] Figure 5 is an enlarged schematic diagram of region V in Figure 4. [Figure 6] Figure 6 is a schematic partial cross-sectional view showing a first modified example of the conductive member shown in Figure 2. [Figure 7] Figure 7 is a schematic partial cross-sectional view showing a second modified example of the conductive member shown in Figure 2. [Figure 8] Figure 8 is a schematic partial cross-sectional view showing a third modified example of the conductive member shown in Figure 2. [Figure 9] Figure 9 is a schematic partial cross-sectional view showing a fourth modified example of the conductive member shown in Figure 2. [Figure 10] Figure 10 is a schematic partial cross-sectional view showing a fifth modified example of the conductive member shown in Figure 2. [Figure 11] Figure 11 is a flowchart illustrating the manufacturing method of the conductive member shown in Figure 2. [Figure 12] Figure 12 is a schematic diagram illustrating the manufacturing method of the conductive member shown in Figure 2. [Figure 13] Figure 13 is a schematic diagram illustrating the manufacturing method of the conductive member shown in Figure 2. [Figure 14] Figure 14 is a schematic diagram illustrating the manufacturing method of the conductive member shown in Figure 2. [Figure 15] Figure 15 is a schematic diagram illustrating the manufacturing method of the conductive member shown in Figure 2. [Figure 16] Figure 16 is a schematic diagram illustrating the manufacturing method of the conductive member shown in Figure 2. [Figure 17] Figure 17 is a schematic cross-sectional view of the electrolytic apparatus according to Embodiment 2. [Figure 18] Figure 18 is a schematic cross-sectional view of a conductive member constituting a modified example of the electrolytic apparatus shown in Figure 17. [Modes for carrying out the invention]

[0006] [Issues this disclosure aims to address] The conventional fuel cells and electrolytic devices described above have a complex structure around the electrodes, consisting of multiple components. This has resulted in increased manufacturing costs due to factors such as a higher number of parts and a more complex manufacturing process.

[0007] This disclosure was made to solve the above-mentioned problems and aims to provide fuel cells and electrolytic devices that can reduce manufacturing costs. [Effects of this disclosure] According to this disclosure, fuel cells and electrolytic devices that can reduce manufacturing costs can be obtained.

[0008] [Description of Embodiments in this Disclosure] (1) A conductive member according to the present disclosure comprises a first layer and a second layer. The first layer is porous. The second layer is laminated on the first layer. The first layer is used as a current collector for a fuel cell or as an electrode for an electrolytic device. The porosity of the second layer is lower than that of the first layer. The porosity of the second layer is 5% or less.

[0009] In this way, the conductive member can be used as an assembly of a current collector connected to the electrodes of a fuel cell and a partition layer containing a gas flow path. For example, by connecting the first layer to the electrodes of the cell, the second layer can act as a partition layer, and the first layer can act as both a gas flow path and a current collector. As a result, the number of fuel cell components and manufacturing steps can be reduced compared to when the current collector and partition layer are connected to the cell individually.

[0010] Further, the conductive member described above can also be used as an electrode for an electrolysis device. For example, the first layer can function as a porous electrode of the electrolysis device, and the second layer can function as a support that supports the electrode. As a result, the number of components and the number of manufacturing steps of the electrolysis device can be reduced compared to a case where the electrode and the support are separately provided in the electrolysis device. Consequently, the manufacturing cost of a fuel cell or an electrolysis device can be reduced.

[0011] (2) The conductive member according to (1) above may further include a third layer. The third layer may be a porous body that is located on a side of the second layer opposite to a side where the first layer is located, and is laminated on the second layer. A plurality of pores may be dispersedly formed in the third layer. A porosity of the third layer may be higher than a porosity of the second layer. The second layer may not have through-holes.

[0012] In this case, a cell laminate of a fuel cell can be easily formed by alternately laminating the conductive member and fuel cell cells. For example, when the conductive member is laminated and arranged between a first cell and a second cell, the first layer functions as a gas (e.g., air) flow path and a current collector for an electrode of the first cell. The third layer functions as a gas (e.g., hydrogen) flow path and a current collector for an electrode of the second cell. The second layer functions as a partition layer (interconnector) that partitions the first cell side and the second cell side. As a result, the manufacturing cost of the fuel cell can be reduced.

[0013] (3) In the conductive member according to (2) above, the porosity of the first layer and the third layer may be 50% or more. In this case, a sufficient gas flow rate can be secured in the first layer and the third layer. Therefore, the performance of the fuel cell can be improved.

[0014] (4) In the conductive member according to (2) or (3) above, a ratio of a total thickness of the first layer and the third layer to a total thickness of the first layer, the second layer, and the third layer may be 10% or more and 90% or less. The thickness of the first layer and the thickness of the third layer may be substantially the same, or the thickness of the first layer and the thickness of the third layer may be different from each other. The configuration of the conductive member can be adjusted according to the device configuration of the fuel cell.

[0015] (5) In the conductive members described in (2) to (4) above, the material constituting the first layer, the material constituting the second layer, and the material constituting the third layer may each include at least one selected from the group consisting of nickel, cobalt, manganese, iron, copper, chromium, aluminum, zinc, titanium, tin, and alloys thereof.

[0016] In this case, when the conductive member is applied to a fuel cell or electrolytic device, the performance of the fuel cell or electrolytic device can be sufficiently ensured. Furthermore, with respect to the conductive member applied to the electrolytic device, the constituent material may include at least one selected from the group consisting of nickel, nickel-aluminum (Ni-Al) alloy, nickel-zinc (Ni-Zn) alloy, and nickel-cobalt (Ni-Co) alloy, or a mixture of at least two selected from the above group.

[0017] (6) In the conductive members described in (2) to (5) above, at least one of the following surfaces may have grooves: the surface of the first layer opposite to the side where the second layer is located, the surface of the first layer on the side where the second layer is located, the surface of the third layer opposite to the side where the second layer is located, and the surface of the third layer on the side where the second layer is located. In this case, the grooves formed in the first or third layer can be used as passages for air or gases such as hydrogen.

[0018] (7) In the conductive members described in (2) to (5) above, at least one of the first layer and the third layer may have through holes. In this case, the through holes formed in the first layer or the third layer can be used as passages for gases such as air, hydrogen, or oxygen.

[0019] (8) In the conductive member described in (1) above, the second layer may have a plurality of through holes. In this case, for example, when the conductive member is used as an electrode in an electrolytic device, gases such as oxygen generated by the electrolysis of water, etc., can be easily discharged to the outside of the conductive member as an electrode through the through holes in the second layer.

[0020] (9) In the conductive member described in (8) above, the first layer may have a plurality of recesses on the surface facing the through-hole of the second layer. In this case, for example, when the conductive member is used as an electrode in an electrolytic device, forming the recesses makes the surface area of ​​the portion of the first layer facing the through-hole of the second layer larger than when the recesses are not formed. This improves the discharge efficiency when oxygen gas and the like generated by electrolysis of water are discharged to the outside of the conductive member through the through-hole of the second layer.

[0021] (10) In the conductive member described in (8) or (9) above, the material constituting the first layer and the material constituting the second layer may each include at least one selected from the group consisting of nickel, cobalt, manganese, iron, copper, chromium, aluminum, zinc, titanium, tin, and alloys thereof.

[0022] In this case, when the conductive member is applied to a fuel cell or electrolytic device, the performance of the fuel cell or electrolytic device can be sufficiently ensured. Furthermore, with respect to the conductive member applied to the electrolytic device, the constituent material may include at least one selected from the group consisting of nickel, nickel-aluminum (Ni-Al) alloy, nickel-zinc (Ni-Zn) alloy, and nickel-cobalt (Ni-Co) alloy, or a mixture of at least two selected from the above group.

[0023] (11) In the conductive members described in (1) to (10) above, the first layer may have a plurality of first holes, a plurality of second holes, and a plurality of third holes. The diameter of the plurality of first holes may be 1 mm or more. The diameter of the plurality of second holes may be 100 μm or more and less than 1 mm. The diameter of the plurality of third holes may be less than 100 μm. In this case, the surface area of ​​the first layer can be increased by forming holes of various sizes as described above.

[0024] (12) The fuel cell relating to this disclosure comprises any of the conductive members described in (2) to (7) and (11) above. In this case, the increase in the manufacturing cost of the fuel cell can be suppressed.

[0025] (13) The electrolytic apparatus according to this disclosure comprises any of the conductive members described in (8) to (11) above. In this case, an increase in the manufacturing cost of the electrolytic apparatus can be suppressed.

[0026] [Details of the embodiments of this disclosure] (Embodiment 1) <Configuration and effects of fuel cells and conductive materials> Figure 1 is a schematic cross-sectional view of a fuel cell 100 according to Embodiment 1. Figure 2 is a schematic partial cross-sectional view of a conductive member 10 constituting the fuel cell 100 shown in Figure 1. Figure 3 is a partially enlarged schematic view of the first layer 1 of the conductive member 10 shown in Figure 2. Figure 4 is an enlarged schematic view of region IV in Figure 3. Figure 5 is an enlarged schematic view of region V in Figure 4. Figures 3 to 5 show cross-sections of the conductive member 10.

[0027] As shown in Figure 1, the fuel cell 100 has a structure (cell stack structure) in which cell structures 50 and conductive members 10 are alternately stacked. The cell structure 50 includes two electrodes (anode and cathode) and an electrolyte layer (for example, a solid electrolyte layer) placed between the two electrodes. The conductive member 10 includes a first layer 1 as a porous layer 61, a second layer 2 as a partition layer 62, and a third layer 3 as a porous layer 63. The second layer 2 is stacked on the first layer 1. The third layer 3 is located on the opposite side from the side where the first layer 1 is located, as seen from the second layer 2. Multiple pores are dispersed in the first layer 1 and the third layer 3. The conductive member 10 is formed by stacking the third layer 3, the second layer 2, and the first layer 1 and fixing them to each other. The first layer 1, the second layer 2, and the third layer are all made of a conductor.

[0028] The porous first layer 1 is connected, for example, to the anode of the cell structure 50. The first layer 1 serves as both a component that supplies fuel such as hydrogen to the anode and a conductor (current collector) that has a current collection function for the anode of the cell structure 50.

[0029] The second layer 2, stacked beneath the first layer 1, can function as a current collector for a single cell structure 50, but here it functions as a partition layer 62 separating the gas supplied to the adjacent first layer 1 from the gas supplied to the third layer. The porosity of the second layer 2 is lower than that of the first layer 1 and the third layer 3. The second layer 2 does not have through holes that extend from the surface on the first layer 1 side to the surface on the third layer 3 side.

[0030] The third layer 3, a porous material stacked beneath the second layer 2, is connected to the cathode of a cell structure 50 that is different from the cell structure 50 to which the first layer 1 is connected. The third layer 3 serves as both a component that supplies air to the cathode and a current collector for the cathode of the other cell structure 50.

[0031] As shown in Figure 1, by alternately stacking the cell structure 50 and the conductive member 10, a fuel cell cell 70 is constructed, consisting of the cell structure 50, a first layer 1 as a porous layer 61 connected to the anode of the cell structure 50, a second layer 2 as a partition wall layer 62 connected to the first layer 1, a third layer 3 as a porous layer 63 connected to the cathode of the cell structure 50, and a second layer 2 as a partition wall layer 62 connected to the third layer 3.

[0032] The porosity of the first layer 1 and the third layer 3 is 50% or more. In this case, sufficient gas flow rate can be secured in the first layer 1 and the third layer 3. Therefore, the performance of the fuel cell 100 can be improved. The porosity of the first layer 1 and the third layer 3 may be 60% or more, or 70% or more. Alternatively, the porosity of the first layer 1 and the third layer 3 may be 40% or more, or 30% or more. The porosity of the second layer 2 is 5% or less. The porosity of the second layer 2 may be 4% or less, or 3% or less. In this case, the second layer 2 can function as a partition layer separating the gas supplied to the first layer 1 and the gas supplied to the third layer 3.

[0033] The porosity of the first layer 1, the second layer 2, or the third layer 3 is defined by the following formula. Porosity (%) = [1 - {M / (V × d)}] × 100 M: Mass [g] of the sample to be measured in Layer 1, Layer 2, or Layer 3. V: Volume of the external shape of the sample being measured [cm³] 3 ] d: Density of the material constituting the sample being measured [g / cm³] 3 ] The "volume of external shape" mentioned above refers to the apparent volume of the sample being measured, which is the sum of the volume of pores (stomata) and the volume of the parts other than the pores in the sample being measured. Note that the volume of pores here does not include the volume of grooves or through holes that are formed afterward by machining processes such as press working.

[0034] As described above, the conductive member 10 can be used as an assembly of a current collector connected to the electrodes of the cell structure 50 of the fuel cell 100 and a partition wall layer including a gas flow path. Specifically, by alternately stacking the conductive member 10 with the cell structure 50 of the fuel cell 100, the cell stack of the fuel cell 100 can be easily formed. As a result, the number of parts and manufacturing processes of the fuel cell 100 can be reduced compared to when the current collector and partition wall layer are individually connected to the cell structure 50. Therefore, by applying the conductive member 10, the manufacturing cost of the fuel cell 100 can be reduced.

[0035] As shown in Figure 2, in the conductive member 10, the ratio of the total thickness of the first layer 1 and the third layer 3 (T1+T3) to the sum of the thicknesses T4 of the first layer 1 (T1), the second layer 2 (T2), and the third layer 3 (T3) is 10% to 90%. This ratio may also be 20% to 80% or 30% to 70%. In this case, when the conductive member 10 is applied to the fuel cell 100, the first layer 1 and the third layer 3 can fully perform their functions as a current collector and as a gas (fuel or air) supplying member. The thicknesses T1 of the first layer 1 and T3 of the third layer 3 may be substantially the same, or they may be different. This allows the configuration of the conductive member 10 to be adjusted to match the device configuration of the fuel cell 100.

[0036] As shown in Figures 3 to 5, in the conductive member 10 (see Figure 1), the plurality of holes formed in the first layer 1 include a plurality of first holes 1a, a plurality of second holes 1b, and a plurality of third holes 1c. The diameter of the plurality of coarse holes, the plurality of first holes 1a, is, for example, 1 mm or more. The diameter of the plurality of medium-diameter holes, the plurality of second holes 1b, is, for example, 100 μm or more and less than 1 mm.

[0037] As shown in Figure 4, the second pore 1b is formed in the portion of the first layer 1 located between the first pores 1a. The diameter of the multiple small-diameter third pores 1c is, for example, less than 100 μm. As shown in Figure 5, the third pores 1c are formed in the portion of the first layer 1 located between the second pores 1b. The first layer 1 may also contain oxide 1d, as shown in Figure 5. The size of the oxide 1d (for example, the maximum width or area of ​​oxide 1d in Figure 5) may be similar to the size of the third pores 1c (for example, the maximum width or area of ​​the third pores 1c in Figure 5). The oxide 1d may be, for example, zirconia.

[0038] The multiple holes formed in the third layer 3 may also include a first hole 1a, a second hole 1b, and a third hole 1c, similar to the first layer 1. The third layer 3 may also contain an oxide 1d, similar to the first layer 1. In this case, the surface area of ​​the first layer 1 or the third layer 3 can be increased by forming holes of various sizes (first hole 1a, second hole 1b, third hole 1c) as described above. Furthermore, by forming first holes 1a, second holes 1b, and third holes 1c of different sizes as described above, the first layer 1 and the third layer 3 can be given different functions, such as supplying gas (fuel or air) to the cell structure 50 and functioning as a current collector.

[0039] The diameters of the first hole 1a, the second hole 1b, and the third hole 1c can be measured using Hiraizumi Yoko Co., Ltd.'s "PORE!SCAN" or by a combination of microscope observation and mercury intrusion method.

[0040] The materials constituting the first layer 1, the second layer 2, and the third layer 3 each include at least one selected from the group consisting of nickel (Ni), cobalt (Co), manganese (Mn), iron (Fe), copper (Cu), chromium (Cr), aluminum (Al), zinc (Zn), titanium (Ti), tin (Sn), and alloys thereof. More specifically, the material constituting the first layer 1 may include elements whose oxide crystal structure is a spinel structure. For example, the first layer 1 may include at least one element selected from the group consisting of nickel, cobalt, manganese, iron, and copper. The materials constituting the second layer 2 and the third layer 3 may be highly heat-resistant alloys, such as iron-chromium (Fe-Cr) alloys represented by stainless steel. In this case, the performance of the fuel cell 100 can be sufficiently ensured when the conductive member 10 is applied to the fuel cell 100. In other configurations, for example, the materials constituting the first layer 1, the second layer 2, and the third layer 3 may be highly corrosion-resistant alloys, such as Ni-Cr alloys.

[0041] <Variation> Figure 6 is a schematic partial cross-sectional view showing a first modified example of the conductive member 10 shown in Figure 2. The conductive member 10 shown in Figure 6 basically has the same configuration as the conductive member 10 shown in Figure 2, but differs from the conductive member 10 shown in Figure 2 in that grooves 4 are formed in the first layer 1 and the third layer 3. In the conductive member 10 shown in Figure 6, grooves 4, which are flow paths 41 for fuel such as hydrogen, are formed on the surface 1e on the side where the second layer 2 is located in the first layer 1. Also, grooves 4, which are flow paths 43 for air, are formed on the surface 3e on the side where the second layer 2 is located in the third layer 3.

[0042] Figure 7 is a schematic partial cross-sectional view showing a second modified example of the conductive member 10 shown in Figure 2. The conductive member 10 shown in Figure 7 basically has the same configuration as the conductive member 10 shown in Figure 6, but the arrangement of grooves 4 formed in the first layer 1 and the third layer 3 is different from that of the conductive member 10 shown in Figure 6. In the conductive member 10 shown in Figure 7, grooves 4, which are flow paths 41 for fuel such as hydrogen, are formed on the surface 1f of the first layer 1 opposite to the side where the second layer 2 is located. Also, grooves 4, which are flow paths 43 for air, are formed on the surface 3f of the third layer 3 opposite to the side where the second layer 2 is located.

[0043] Figure 8 is a schematic partial cross-sectional view showing a third modified example of the conductive member 10 shown in Figure 2. The conductive member 10 shown in Figure 8 basically has the same configuration as the conductive member 10 shown in Figure 6, but the arrangement of the grooves 4 formed in the third layer 3 is different from that of the conductive member 10 shown in Figure 6. In the conductive member 10 shown in Figure 8, grooves 4, which are air passages 43, are formed on the surface 3f of the third layer 3 opposite to the side where the second layer 2 is located. In the first layer 1, grooves 4, which are fuel passages 41, are formed on the surface 1e on the side where the second layer 2 is located, similar to the conductive member 10 shown in Figure 6.

[0044] Figure 9 is a schematic partial cross-sectional view showing a fourth modified example of the conductive member 10 shown in Figure 2. The conductive member 10 shown in Figure 9 basically has the same configuration as the conductive member 10 shown in Figure 6, but the arrangement of the grooves 4 formed in the first layer 1 is different from that of the conductive member 10 shown in Figure 6. In the conductive member 10 shown in Figure 9, grooves 4, which are fuel passages 41, are formed on the surface 1f of the first layer 1 opposite to the side where the second layer 2 is located. In the third layer 3, grooves 4, which are air passages 43, are formed on the surface 3e on the side where the second layer is located, similar to the conductive member 10 shown in Figure 6.

[0045] In the conductive member 10 shown in Figures 6 to 9 above, the depth of the groove 4 is not limited to the thickness of the first layer 1 or the third layer 3, and may be 50% or less of the thickness of the first layer 1 or the third layer 3. The planar shape of the groove 4 in a plan view from a direction perpendicular to the surface 1e of the first layer 1 can be any shape, such as a straight line, a grid, a meandering flow path shape with alternating straight and bent sections, an arc shape, or a shape combining multiple concentric circles and straight lines connecting those concentric circles. In addition, in Figures 6 to 9, the groove 4 formed in the first layer 1 and the groove 4 formed in the third layer 3 are arranged to overlap in a plan view, but the groove 4 formed in the first layer 1 and the groove 4 formed in the third layer 3 may be arranged so that at least a portion of them do not overlap in a plan view.

[0046] Figure 10 is a schematic partial cross-sectional view showing a fifth modified example of the conductive member shown in Figure 2. The conductive member 10 shown in Figure 10 basically has the same configuration as the conductive member 10 shown in Figure 2, but differs from the conductive member 10 shown in Figure 2 in that through holes 1g and 3g are formed in the first layer 1 and the third layer 3. In the conductive member 10 shown in Figure 10, a through hole 1g is formed in the first layer 1, reaching from the surface 1e on the side of the second layer 2 to the surface 1f on the opposite side of where the second layer 2 is located. Also, a through hole 3g is formed in the third layer 3, reaching from the surface 3e on the side of the second layer 2 to the surface 3f on the opposite side of where the second layer 2 is located.

[0047] The planar shapes of the through holes 1g and 3g can be any shape, such as a circle, square, polygon, or ellipse. In addition, grooves (not shown) connecting multiple through holes 1g may be formed on the surface 1e or surface 1f of the first layer 1. In the third layer 3, grooves (not shown) connecting multiple through holes 3g may be formed on the surface 3e or surface 3f. In Figure 10, the through holes 1g formed in the first layer 1 and the through holes 3g formed in the third layer 3 are arranged to overlap in a plan view, but the through holes 1g formed in the first layer 1 and the through holes 3g formed in the third layer 3 may be arranged so that at least a portion of them do not overlap in a plan view.

[0048] In the conductive member 10 with the configuration shown in Figures 6 to 10, the grooves 4 or through holes 1g, 3g formed in the first layer 1 or the third layer 3 can be used as flow paths for air or gases such as hydrogen. Therefore, the performance of the fuel cell 100 to which the conductive member 10 is applied can be improved.

[0049] <Method for manufacturing conductive materials> Figure 11 is a flowchart illustrating the manufacturing method of the conductive member shown in Figure 2. Figures 12 to 16 are schematic diagrams illustrating the manufacturing method of the conductive member 10 shown in Figure 2.

[0050] As shown in Figure 11, the manufacturing method for the conductive member 10 first involves a raw material preparation step (S10). In this step (S10), raw material powders and a binder, which will be the raw materials for the conductive member 10, are prepared. As raw material powders, metal powders that make up the conductive member 10 and pore-forming materials for forming multiple holes are prepared.

[0051] Next, a mixing step (S20) is performed. In this step (S20), the raw material powder and binder prepared in step (S10) are mixed to form a raw material paste.

[0052] Next, the sheet molding process (S30) is carried out. In this process (S30), the paste of the raw materials described above is molded into a sheet to obtain a sheet member as an intermediate.

[0053] Next, a surface structure forming process (S40) is performed. In this process (S40), a surface structure such as grooves, recesses, and holes is formed on the surface of the sheet member according to the application and required performance of the conductive member 10. In this process (S40), for example, as shown in Figure 12, processing is performed on the sheet member 20 using processing rolls 21a and 21b. As shown in Figure 12, the processing rolls 21a and 21b are positioned opposite each other with the sheet member 20 in between. Surface structures to be transferred to the surface of the sheet member 20 are formed on the surfaces of the rolls 21a and 21b. Through this processing, structures such as holes, recesses, and grooves are formed on the sheet member 20. Furthermore, by using roll processing with rolls 21a and 21b as shown in Figure 12, a surface structure can be continuously formed on the sheet member 20. In addition, the sheet member can be densified by rolling the sheet member 20 with rolls 21a and 21b.

[0054] Next, a heat treatment process (S50) is performed. In this process (S50), the sheet member 20 on which the surface structure has been formed is heated to remove the binder from the sheet member 20 and reduce and sinter the raw material powder. If a pore-forming material is used at this time, the pore-forming material volatilizes or decomposes thermally, forming minute pores in the sheet member. As a result, a conductive sheet is obtained that has the surface structure formed in process (S40) and is to constitute the conductive member 10. Examples of conductive sheets obtained in this way include conductive sheets 30, 31, and 32 of various shapes, as shown in Figures 13 to 15. For example, a conductive sheet 30 with a flat surface can be considered, as shown in Figure 13. Alternatively, as shown in Figure 14, a conductive sheet 31 may be obtained in which a groove structure 31b is formed, which will result in grooves 4, by forming a plurality of protrusions 31a on the surface. Alternatively, by forming through holes in the sheet member 20 during process (S40), a conductive sheet 32 ​​may be obtained in which through holes 32g, which should become through holes 1g (see Figure 10), are formed, as shown in Figure 15.

[0055] Next, a post-processing step (S60) is performed. In this step (S60), a conductive member 10 as shown in Figure 2 is obtained by combining the multiple conductive sheets 30, 31, and 32 obtained in the above step (S50). For example, the conductive member 10 as shown in Figure 2 is formed by laminating and fixing multiple conductive sheets. Alternatively, for example, the conductive member 10 shown in Figure 16 may be obtained by laminating and fixing a conductive sheet 31 having a groove structure 31b as shown in Figure 14, a conductive sheet 30a with a flat surface and relatively low porosity as shown in Figure 13, and a conductive sheet 30b with a flat surface and relatively high porosity. Any conventionally known method can be used for connecting the conductive sheets, such as joining with a bonding material such as solder. The thickness, size, surface shape, etc. of the conductive sheets 30, 31, and 32 to be combined can be appropriately selected according to the characteristics required for the conductive member 10. In this way, the conductive member 10 as shown in Figure 2 can be obtained.

[0056] Alternatively, the formation of the conductive sheet and the formation of the conductive member 10 (joining of multiple conductive sheets) may be carried out simultaneously by stacking multiple sheet members with a surface structure formed on them and then performing the heat treatment process (S50).

[0057] (Embodiment 2) <Configuration and effects of electrolytic devices and conductive components> Figure 17 is a schematic cross-sectional view of an electrolytic device 200 according to Embodiment 2. Figure 17 shows the electrolytic cell 210 of the electrolytic device 200. The electrolytic device 200 may have a plurality of electrolytic cells 210. The electrolytic cell 210 of the electrolytic device 200 mainly comprises two bipolar plates 201, a diaphragm 202, an oxygen electrode 203, a hydrogen electrode 204, and a support column 205. The oxygen electrode 203 and the hydrogen electrode 204 are arranged so as to sandwich the diaphragm 202. The two bipolar plates 201 are arranged so as to sandwich the oxygen electrode 203 and the hydrogen electrode 204.

[0058] The oxygen electrode 203 and the hydrogen electrode 204 are supported by a support column 205. A pipe 207 is installed at the bottom 206 located below the oxygen electrode 203 and the hydrogen electrode 204. The pipe 207 supplies an electrolyte solution (for example, alkaline water such as an aqueous KOH solution) to the electrolytic device 200. When power is supplied to the oxygen electrode 203 and the hydrogen electrode 204, the solution is electrolyzed. As a result, oxygen is generated from the oxygen electrode 203 side, as indicated by arrow 208, and hydrogen is generated from the hydrogen electrode 204 side, as indicated by arrow 209. In the electrolytic device 200 shown in Figure 17, a conductive member 10 is used as the oxygen electrode 203.

[0059] The oxygen electrode 203, which serves as the conductive member 10, is a laminate formed by stacking a porous layer 203a and a support layer 203b. Multiple pores are dispersed in the porous layer 203a, which serves as the first layer 1. Through holes are formed in the porous layer 203a, reaching from the surface on the diaphragm 202 side to the surface on the support layer 203b side. The structure of the porous layer 203a is the same as that of the first layer 1 of the conductive member 10 in Embodiment 1 shown in Figures 3 to 5. In other words, the porous layer 203a also has multiple first pores 1a (see Figure 3), multiple second pores 1b (see Figure 4), and multiple third pores 1c (see Figure 5), similar to the first layer 1 shown in Figures 3 to 5.

[0060] The support layer 203b, which is the second layer 2, is laminated and fixed to the porous layer 203a, which is the first layer 1. The porosity of the support layer 203b, which is the second layer 2, is lower than that of the porous layer 203a, which is the first layer 1. Multiple through holes are formed in the support layer 203b, reaching from one surface to the other. The through holes formed in the support layer 203b serve as exhaust paths for the oxygen gas generated at the oxygen electrode 203. In the support layer 203b, the porosity of the parts where the through holes are not formed is, for example, 5% or less.

[0061] In this way, the conductive member 10 can be used as an oxygen electrode 203 for the electrolytic device 200. That is, the first layer 1 can be used as a porous layer 203a, which is a porous electrode for the electrolytic device 200, and the second layer 2 can be used as a support layer 203b that supports the porous layer 203a. As a result, the number of parts and manufacturing steps for the electrolytic device 200 can be reduced compared to when a porous electrode and a support are individually installed as an oxygen electrode 203 in the electrolytic device 200. As a result, the manufacturing cost of the electrolytic device 200 can be reduced.

[0062] The hydrogen electrode 204 mainly comprises a porous layer 204a and a cushion layer 204c. The porous layer 204a is positioned to face the diaphragm 202. The cushion layer 204c is connected to the back surface of the porous layer 204a opposite to the surface facing the diaphragm 202. The porous layer 204a is made of a conductive material. Multiple through holes are formed in the porous layer 204a, reaching from the surface on the diaphragm 202 side to the surface on the cushion layer 204c side. As the porous layer 204a, for example, a porous metal such as Cellmet (registered trademark) or mesh metal can be used. The conductive member 10 can also be used as the hydrogen electrode 204 for the electrolytic device 200. In this case, the presence of the support layer allows the hydrogen electrode 204 to effectively receive the pressing force from the support column 205 and the cushion layer 204c, which are located on the opposite side of the diaphragm 202 from the view of the hydrogen electrode 204.

[0063] Any material with elasticity can be used as the material for the cushion layer 204c. For example, a woven fabric mattress, a coil mattress, or a component including a leaf spring structure can be used as the cushion layer 204c. Any configuration can be adopted for the cushion layer 204c as long as a pressing force can be applied from the support column 205, which is located on the opposite side of the diaphragm 202 from the hydrogen electrode 204, toward the hydrogen electrode 204.

[0064] The material constituting the porous layer 203a as the first layer 1 and the material constituting the support layer 203b as the second layer 2 each include at least one selected from the group consisting of nickel, cobalt, manganese, iron, copper, chromium, aluminum, zinc, titanium, tin, and alloys thereof. More specifically, with respect to the oxygen electrode 203 as a conductive member 10 applied to the electrolytic device 200, the constituent material may include at least one selected from the group consisting of nickel, nickel-aluminum (Ni-Al) alloy, nickel-zinc (Ni-Zn) alloy, and nickel-cobalt (Ni-Co) alloy, or a mixture of at least two selected from the above group. In this case, the performance of the electrolytic device 200 can be sufficiently ensured when the conductive member 10 is applied to the electrolytic device 200.

[0065] <Variation> Figure 18 is a schematic cross-sectional view of a conductive member 10 that constitutes a modified example of the electrolytic apparatus 200 shown in Figure 17. Figure 18 corresponds to the schematic cross-sectional view of the conductive member 10 in the horizontal direction in the electrolytic apparatus 200 shown in Figure 17. The electrolytic apparatus equipped with the conductive member 10 shown in Figure 18 basically has the same configuration as the electrolytic apparatus 200 shown in Figure 17, but the configuration of the oxygen electrode 203 as the conductive member 10 differs from that of the electrolytic apparatus 200 shown in Figure 17. The conductive member 10 of the electrolytic apparatus shown in Figure 18 is an oxygen electrode 203, comprising a porous layer 203a as a first layer 1 and a support layer 203b as a second layer 2. Multiple through holes 203ba are formed in the support layer 203b. In the porous layer 203a as the first layer 1, multiple recesses 203aa are formed on the surface exposed from the through holes 203ba of the support layer 203b as the second layer 2. In this case, by forming the recess 203aa, the surface area of ​​the porous layer 203a as the first layer 1 that faces the through-hole 203ba of the support layer 203b can be made larger than when the recess 203aa is not formed. Therefore, in addition to the same effects as the electrolytic device 200 shown in Figure 17, when the oxygen gas generated by electrolyzing water, etc., is discharged to the outside of the oxygen electrode 203 through the through-hole 203ba of the support layer 203b, the oxygen gas can be discharged to the outside more efficiently.

[0066] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the embodiments described above, and all modifications within the meaning and scope of the claims are intended to be included. [Explanation of Symbols]

[0067] 1 First layer, 1a First hole, 1b Second hole, 1c Third hole, 1d Oxide, 1e, 1f, 3e, 3f Surface, 1g, 3g, 32g, 203ba Through hole, 2 Second layer, 3 Third layer, 4 Groove, 10 Conductive member, 20 Sheet member, 21a, 21b Roll, 30, 30a, 30b, 31, 32 Conductive sheet, 31a Protrusion, 31b Groove structure, 41, 43 Flow channel, 50 Cell structure, 61, 63, 203a, 204a Porous layer, 62 Partition layer, 70 Cell, 100 Fuel cell, 200 Electrolyzer, 201 Bipolar plate, 202 Diaphragm, 203 Oxygen electrode, 203aa Recess, 203b Support layer, 204 Hydrogen electrode, 204c Cushion layer, 205 Support column, 206 base, 207 piping, 208, 209 arrows, 210 electrolytic cell.

Claims

1. The first layer is a porous material, The first layer comprises a second layer laminated on top of the first layer, The first layer is used as an electrode for an electrolytic device. The porosity of the second layer is lower than that of the first layer. The porosity of the second layer is 5% or less. The preceding second layer has a plurality of through holes, The first layer is a conductive member having a plurality of recesses on the surface facing the through hole of the second layer.

2. The conductive member according to claim 1, wherein the material constituting the first layer and the material constituting the second layer each include at least one selected from the group consisting of nickel, cobalt, manganese, iron, copper, chromium, aluminum, zinc, titanium, tin, and alloys thereof.

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