Metal sheet, battery, nickel-zinc battery, and method for producing metal sheet

Abstract

The present disclosure provides a metal sheet which is plate-shaped and has a principal surface positioned toward one side in the thickness direction, said sheet having a plurality of struts and a node section where the end sections of the plurality of struts are connected to one another, and being configured in a manner such that a network structure is formed from the struts and the node section, the plurality of struts are tightly adhered to one another, and there are a plurality of through-holes which pass through the principal surface in the thickness direction.

Description

Metal sheet, battery, nickel-zinc battery, and method for manufacturing the metal sheet

[0001] The present disclosure relates to metal sheets, batteries, nickel-zinc batteries, and methods for manufacturing metal sheets.

[0002] For example, Japanese Patent Laid-Open Publication No. 2017-188212 (Patent Document 1) describes a zinc electrode for a nickel-zinc storage battery and a method for manufacturing the same. The zinc electrode for a nickel-zinc storage battery described in Patent Document 1 has a zinc active material attached to a punched metal current collector with a porosity of 15 to 45%.

[0003] Japanese Patent Application Laid-Open No. 2017-188212

[0004] A metal sheet according to the present disclosure is a flat metal sheet having a main surface located on one side in a thickness direction, and having a plurality of strut portions and node portions at which ends of a plurality of the strut portions are connected to each other, wherein a mesh structure is formed by the strut portions and the node portions and the plurality of strut portions are in close contact with each other, and wherein the metal sheet has a plurality of through holes that penetrate the main surface in the thickness direction.

[0005] A battery according to the present disclosure is a battery comprising the metal sheet of the present disclosure as a current collector.

[0006] A nickel-zinc battery according to the present disclosure is a nickel-zinc battery comprising the metal sheet of the present disclosure as a current collector.

[0007] A method for manufacturing a metal sheet according to the present disclosure includes the steps of: preparing a flat porous metal body having a skeleton with a three-dimensional network structure; and rolling the porous metal body in the thickness direction to manufacture the metal sheet of the present disclosure.

[0008] FIG. 1 is a photograph showing the appearance of an example of a metal sheet according to the present disclosure. FIG. 2 is a photograph showing the results of observing the main surface of an example of a metal sheet according to the present disclosure with a scanning electron microscope (SEM). FIG. 3 is a partially enlarged photograph of the photograph shown in FIG. 2. FIG. 4 is a photograph showing the results of observing the cross section of an example of a metal sheet according to the present disclosure with a scanning electron microscope (SEM). FIG. 5 is a partially enlarged photograph of the photograph shown in FIG. 4. FIG. 6 is a partially enlarged photograph of the photograph shown in FIG. 5. FIG. 7 is a partially enlarged photograph of the photograph shown in FIG. 6. FIG. 8 is a diagram showing an outline of an example of a method for manufacturing a metal sheet according to the present disclosure. FIG. 9 is an electron microscope photograph of a cross section of a porous metal body having a skeleton with a three-dimensional network structure used in the method for manufacturing a metal sheet according to the present disclosure. FIG. 10 is a photograph showing the results of observing the main surface of another example of a metal sheet according to the present disclosure with a scanning electron microscope (SEM). FIG. 11 is a photograph showing the results of observing the cross section of another example of a metal sheet according to the present disclosure with a scanning electron microscope (SEM). Fig. 12 is a partially enlarged photograph of the photograph shown in Fig. 11. Fig. 13 is a partially enlarged photograph of the photograph shown in Fig. 12. Fig. 14 is a photograph showing the results of observing the main surface of the punched metal with a scanning electron microscope (SEM). Fig. 15 is a photograph showing the results of observing the cross section of the punched metal with a scanning electron microscope (SEM). Fig. 16 is a partially enlarged photograph of the photograph shown in Fig. 15.

[0009] [Problem to be Solved by the Present Disclosure] As mentioned above, Patent Document 1 discloses the use of a perforated metal with an opening rate of 15 to 45% as a current collector for a zinc electrode for a nickel-zinc storage battery. The perforated metal is a metal plate with a plurality of through holes formed therein, and it is said that the through holes filled with a zinc active material can be used as an electrode. However, the through holes formed in the perforated metal are uniformly circular and have a relatively large pore diameter of about several millimeters, which poses a problem in terms of the retention of the active material.

[0010] The present disclosure has been made in view of the above-mentioned problems of the conventional art. More specifically, the present disclosure aims to provide a metal sheet that can be used as a current collector for a battery and has excellent active material retention properties.

[0011] Effect of the Present Disclosure According to the present disclosure, it is possible to provide a metal sheet that can be used as a current collector for a battery and has excellent active material retention properties.

[0012] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be described. (1) The metal sheet of the present disclosure is a flat metal sheet having a main surface located on one side in the thickness direction, the metal sheet having a plurality of strut portions and node portions at which ends of the plurality of strut portions are connected to each other, the strut portions and the node portions forming a mesh-like structure, the plurality of strut portions being in close contact with each other, and the metal sheet having a plurality of through-holes penetrating the main surface in the thickness direction. According to the aspect of the disclosure described in (1) above, it is possible to provide a metal sheet that can be used as a current collector for a battery and has excellent active material retention. Note that the strut portions refer to rod- or plate-shaped portions that form the mesh-like structure. Furthermore, the node portions refer to portions at which ends of the plurality of strut portions are connected to each other.

[0013] (2) In the metal sheet described in (1) above, the strut portion may be strip-shaped. According to the aspect of the disclosure described in (2) above, a thinner metal sheet can be provided.

[0014] (3) In the metal sheet described in (1) or (2) above, the strut portions may be layered in a twisted position. According to the disclosed aspect described in (3) above, it is possible to provide a metal sheet in which the strut portions are layered in a thickness direction of the metal sheet, forming a more complex mesh structure.

[0015] (4) In the metal sheet according to any one of (1) to (3), the diameter of the through holes may not be constant in the thickness direction of the metal sheet. According to the embodiment of the disclosure described in (4), a metal sheet having higher active material retention properties when used as a current collector of a battery can be provided. Note that the diameter of the through holes in the main surface refers to the longest diameter of the through holes at the outermost surface of the main surface.

[0016] (5) In the metal sheet according to any one of (1) to (4), the through holes in the main surface may have a diameter of 1 μm or more and 900 μm or less. According to the disclosed aspect of (5), it is possible to provide a metal sheet that has high retention of active material and retains a large amount of active material when used as a current collector of a battery.

[0017] (6) In the metal sheet according to any one of (1) to (5), the number of the through holes on the main surface may be 250 to 2500 per 500 μm square. According to the aspect of the disclosure described in (6), it is possible to provide a metal sheet that is lighter and retains a larger amount of active material when used as a current collector for a battery.

[0018] (7) The metal sheet according to any one of (1) to (6) above may have an aperture ratio of 10% or more and 40% or less. According to the disclosed embodiment of (7) above, it is possible to provide a metal sheet that is lighter and retains a larger amount of active material when used as a current collector for a battery. The aperture ratio refers to the ratio (percentage) of the area of ​​the through holes to the apparent area of ​​the main surface of the metal sheet.

[0019] (8) The metal sheet according to any one of (1) to (7) above has a surface and an interior, the surface including the main surface, a back surface opposite the main surface, and an outer peripheral surface of the metal sheet, the interior being covered by the surface, and the metal sheet may have an independent space within the interior surrounded by the strut portion and the node portion. According to the aspect of the disclosure described in (8) above, a lighter metal sheet can be provided.

[0020] (9) In the metal sheet according to any one of (1) to (8), three or more of the strut portions may be connected to the node portion. According to the aspect of the disclosure described in (9), it is possible to provide a metal sheet in which a more complex mesh structure is formed by the strut portions and the node portions.

[0021] (10) In the metal sheet according to any one of (1) to (9), the thickness of the strut portion may be 1 μm or more and 10 μm or less. According to the aspect of the disclosure described in (10), a thinner metal sheet can be provided. Note that the thickness of the strut portion refers to the thickness of the central portion between the end of one strut portion connected to the node portion and the other end.

[0022] (11) In the metal sheet according to any one of (1) to (10), the length of the strut portion may be 50 μm or more and 500 μm or less. According to the aspect of the disclosure described in (11), it is possible to provide a metal sheet in which a finer mesh structure is formed by the strut portions and the node portions. Note that the length of a strut portion refers to the distance from one end of a strut portion connected to a node portion to the other end.

[0023] (12) In the metal sheet according to any one of (1) to (11) above, the strut portions may have a width of 100 μm or more and 3000 μm or less. According to the aspect of the disclosure described in (12) above, it is possible to provide a metal sheet in which a finer mesh structure is formed by the strut portions and the node portions. Note that the width of the strut portion refers to the width of the central portion between the end of one strut portion connected to the node portion and the other end.

[0024] (13) In the metal sheet according to any one of (1) to (12), the strut portions may include portions in which two or more and five or less layers are laminated in the thickness direction of the metal sheet. According to the aspect of the disclosure described in (13), it is possible to provide a metal sheet in which a more complex mesh structure is formed by the strut portions and node portions.

[0025] (14) The metal sheet according to any one of (1) to (13) above may have a thickness of 10 μm or more and 100 μm or less. According to the embodiment of the disclosure described in (14) above, a thin metal sheet can be provided. The thickness of the metal sheet refers to the distance between the main surface of the flat metal sheet and the back surface located on the opposite side.

[0026] (15) The metal sheet according to any one of (1) to (14) above may have a plurality of recesses on the main surface. According to the embodiment of the disclosure described in (15) above, a metal sheet having high active material retention when used as a current collector of a battery can be provided. Note that the recesses do not include the aforementioned through holes.

[0027] (16) In the metal sheet according to any one of (1) to (15), the diameter of the recess on the main surface may be 1 μm or more and 900 μm or less. According to the aspect of the disclosure described in (16), a metal sheet can be provided that has higher active material retention when used as a current collector for a battery. Note that the diameter of the recess on the main surface refers to the longest diameter of the recess on the outermost surface of the main surface.

[0028] (17) In the metal sheet according to (15) or (16), the diameter of the recess may not be constant in the thickness direction of the metal sheet. According to the embodiment of the disclosure described in (17), it is possible to provide a metal sheet that has a higher ability to retain active material when used as a current collector of a battery.

[0029] (18) In the metal sheet according to any one of (15) to (17), the number of recesses on the main surface may be 75 to 750 per 500 μm square. According to the disclosed aspect of (18), it is possible to provide a metal sheet that retains a large amount of active material when used as a current collector for a battery.

[0030] (19) The metal sheet according to any one of (1) to (18) above may contain at least one selected from the group consisting of copper, nickel, aluminum, gold, silver, tin, and chromium. According to the embodiment of the disclosure described in (19) above, a metal sheet usable for various applications can be provided.

[0031] (20) In the metal sheet according to any one of (8) to (19), the surface may contain tin and the interior may contain copper. According to the disclosed aspect of (20), a metal sheet suitable for use as a current collector for a nickel-zinc battery can be provided.

[0032] (21) In the metal sheet according to any one of (1) to (19), the strut portion and the node portion may have a surface and an interior portion covered by the surface, the surface containing tin, and the interior portion containing copper. According to the aspect of the disclosure described in (21), it is possible to provide a metal sheet suitable for use as a current collector for a nickel-zinc battery.

[0033] (22) A battery according to the present disclosure includes, as a current collector, the metal sheet according to any one of (1) to (21). According to the disclosed embodiment of (22), a battery having excellent active material retention can be provided.

[0034] (23) A nickel-zinc battery according to the present disclosure includes, as a current collector, the metal sheet according to (20) or (21). According to the disclosed embodiment of (23), a nickel-zinc battery having excellent active material retention can be provided.

[0035] (24) A method for manufacturing a metal sheet according to the present disclosure includes the steps of: preparing a metal porous body having a flat plate-like structure and a skeleton with a three-dimensional network structure; and rolling the metal porous body in a thickness direction to manufacture the metal sheet according to (1). According to the aspect of the disclosure described in (24), a method for manufacturing a metal sheet capable of manufacturing the metal sheet according to the present disclosure can be provided.

[0036] [Details of the embodiments of the present disclosure] Specific examples of metal sheets, batteries, nickel-zinc batteries, and methods for manufacturing metal sheets according to the embodiments of the present disclosure will be described in more detail below, with reference to the accompanying drawings as appropriate. The present disclosure is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims. In the following drawings, the same or corresponding parts are designated by the same reference symbols, and redundant descriptions will not be repeated.

[0037] <Metal Sheet> The configuration of a metal sheet according to an embodiment of the present disclosure will be described below. FIG. 1 is a photograph showing the appearance of an example of a metal sheet 10. FIG. 2 is a photograph showing the results of observing the main surface of the metal sheet 10 with a scanning electron microscope (SEM). FIG. 3 is a partially enlarged photograph of the photograph shown in FIG. 2. As shown in FIG. 1, the metal sheet 10 is flat and has a main surface located on one side in the thickness direction. As shown in FIGS. 2 and 3, the metal sheet 10 has a plurality of strut portions 11 and node portions 12 where ends of the plurality of strut portions 11 are connected to each other. The strut portions 11 and node portions 12 form a mesh-like structure. The plurality of strut portions 11 also have portions where they are in close contact with each other. Because the metal sheet 10 has a mesh-like structure formed by the strut portions 11 and the node portions 12, when a battery active material is applied to the metal sheet 10, the active material fills the mesh-like structure. Therefore, the metal sheet 10 can be used as a current collector for a battery electrode, which has excellent active material retention and retention amount. Furthermore, the strut portions 11 are in close contact but not bonded, and can slide at their interfaces, so the metal sheet 10 is strong against bending and has excellent flexibility.

[0038] The struts 11 are rod- or plate-shaped portions that form a mesh structure as shown in Figures 2 and 3, and may be strip-shaped. When the struts 11 are strip-shaped, the thickness of the metal sheet 10 becomes thinner.

[0039] 2 and 3, the node portion 12 is a portion where the ends of a plurality of strut portions 11 are connected to each other. The ends of three or more strut portions 11 may be connected to a node portion 12. In this case, the mesh structure of the metal sheet 10 becomes more complex.

[0040] Fig. 4 shows a photograph of the cross section of the metal sheet 10 observed with a scanning electron microscope (SEM). Fig. 5 shows an enlarged photograph of a portion of Fig. 4, Fig. 6 shows an enlarged photograph of a portion of Fig. 5, and Fig. 7 shows an enlarged photograph of a portion of Fig. 6.

[0041] 3 and 4, the metal sheet 10 has a plurality of through-holes 14 that penetrate the main surface in the thickness direction. This allows the metal sheet 10 to be made lighter. Furthermore, when the metal sheet 10 is used as a current collector of a battery, it is possible to improve the retention of active material.

[0042] The diameter of the through holes 14 may not be constant in the thickness direction of the metal sheet 10. This makes it easier for the active material of a battery to remain in the through holes 14 when the metal sheet 10 is filled with the active material. The diameter of the through holes 14 on the surface of the metal sheet 10 may be 1 μm or more and 900 μm or less. The diameter of the through holes 14 on the main surface refers to the longest diameter of the through holes 14 at the outermost surface of the main surface. In another example, the diameter of the through holes 14 may be 1 μm or more and 500 μm or less. In yet another example, the diameter of the through holes 14 may be 1 μm or more and 250 μm or less. These configurations can further improve the retention and amount of active material when the metal sheet 10 is used as a current collector for a battery, for example.

[0043] The number of through holes 14 may be, for example, 250 to 2,500 per 500 μm square on the main surface. In another example, the number of through holes 14 may be 250 to 1,250 per 500 μm square on the main surface. In yet another example, the number of through holes 14 may be 250 to 625 per 500 μm square on the main surface. Having the number of through holes 14 in the above range on the main surface of the metal sheet 10 allows the metal sheet 10 to be lighter and to retain a larger amount of active material when used as a current collector for a battery. The number of through holes 14 is determined by observing the main surface of the metal sheet 10 with a microscope, counting the number of through holes present within a 500 μm square range at any 10 locations on the main surface, and averaging the counts.

[0044] The metal sheet 10 may have an aperture ratio of 10% or more and 40% or less. The aperture ratio refers to the ratio (percentage) of the area of ​​the through holes 14 to the apparent area of ​​the main surface of the metal sheet 10. In another example, the aperture ratio may be 10% or more and 30% or less. In yet another example, the aperture ratio may be 10% or more and 25% or less. When the aperture ratio of the metal sheet 10 is within the above range, the metal sheet 10 can be lighter and can hold a larger amount of active material when used as a current collector of a battery.

[0045] The metal sheet 10 has a surface and an interior. The surface includes the main surface, a back surface opposite the main surface, and the outer peripheral surface of the metal sheet 10. The interior of the metal sheet 10 is the portion covered by the surface. As shown in FIGS. 6 and 7 , the metal sheet 10 may have an independent space 15 inside surrounded by the strut portions 11 and the node portions 12. The independent space 15 is typically an air gap. Having the independent space 15 inside the metal sheet 10 makes it lighter.

[0046] The thickness of the strut portion 11 may be 1 μm or more and 10 μm or less. The thickness of the strut portion 11 refers to the thickness of the central portion between the end of one strut portion 11 connected to the node portion 12 and the other end. In another example, the thickness of the strut portion 11 may be 1 μm or more and 8 μm or less. In yet another example, the thickness of the strut portion 11 may be 1 μm or more and 5 μm or less. By making the strut portion 11 thinner, it is possible to provide a thinner metal sheet 10.

[0047] The length of the strut portion may be 50 μm or more and 500 μm or less. The length of the strut portion 11 refers to the distance from one end of the strut portion 11 connected to the node portion 12 to the other end. In another example, the length of the strut portion 11 may be 50 μm or more and 250 μm or less. In yet another example, the length of the strut portion 11 may be 50 μm or more and 100 μm or less. When the length of the strut portion 11 is within the above range, a metal sheet 10 having a finer mesh structure can be provided.

[0048] The width of the strut portion 11 may be 100 μm or more and 3000 μm or less. The width of the strut portion 11 refers to the width of the central portion between the end of one strut portion 11 connected to the node portion 12 and the other end. In another example, the width of the strut portion 11 may be 100 μm or more and 1000 μm or less. In yet another example, the width of the strut portion 1110 may be 100 μm or more and 500 μm or less. Having the width of the strut portion 11 within the above range makes it possible to provide a metal sheet 10 with a finer mesh structure.

[0049] A plurality of strut portions 11 may be stacked in the thickness direction of the metal sheet 10. The metal sheet 10 may, for example, include a portion where two or more and five or less strut portions 11 are stacked in the thickness direction of the metal sheet 10. In another example, the metal sheet 10 may include a portion where three or more and four or less strut portions 11 are stacked in the thickness direction of the metal sheet 10. Furthermore, when a plurality of strut portions 11 are stacked in the thickness direction of the metal sheet 10, a plurality of strut portions 11 at twisted positions may overlap in layers. These configurations make the mesh structure of the metal sheet 10 have a more complex shape.

[0050] As shown in FIG. 4 , the metal sheet 10 is very thin. For example, the thickness of the metal sheet 10 may be 10 μm or more and 100 μm or less. The thickness of the metal sheet 10 refers to the distance between the main surface of the flat metal sheet 10 and the back surface located on the opposite side. In another example, the thickness of the metal sheet 10 may be 10 μm or more and 80 μm or less. In yet another example, the thickness of the metal sheet 10 may be 10 μm or more and 50 μm or less. By ensuring that the thickness of the metal sheet 10 is within the above range, a thin metal sheet 10 can be provided. When the metal sheet 10 is thin, for example, the metal sheet 10 can be used as a current collector for a battery electrode, thereby enabling the battery to be made thinner.

[0051] 5, the metal sheet 10 may have a plurality of recesses 13 on its main surface. This allows the metal sheet 10 to retain an active material more effectively when used as a current collector for a battery. Note that the recesses 13 do not include the through-holes 14 described above.

[0052] The diameter of the recesses 13 on the main surface of the metal sheet 10 may be 1 μm or more and 900 μm or less. The diameter of the recesses on the main surface refers to the longest diameter of the recesses on the outermost surface of the main surface. In another example, the diameter of the recesses 13 may be 1 μm or more and 500 μm or less. In yet another example, the diameter of the recesses 13 may be 1 μm or more and 100 μm or less. Furthermore, the diameter of the recesses 13 may not be constant in the thickness direction of the metal sheet 10. These configurations can further improve the retention of active material when the metal sheet 10 is used as a current collector for a battery, for example.

[0053] The number of recesses 13 may be, for example, 75 to 750 per 500 μm square on the main surface. In another example, the number of recesses 13 may be 75 to 500 per 500 μm square on the main surface. In yet another example, the number of recesses 13 may be 75 to 250 per 500 μm square on the main surface. Having the number of recesses 13 on the main surface of the metal sheet 10 within the above range allows the metal sheet 10 to retain a large amount of active material when used as a current collector for a battery. The number of recesses 13 is determined by observing the main surface of the metal sheet 10 with a microscope, counting the number of recesses 13 present within a 500 μm square range at any 10 locations on the main surface, and averaging the number. The number of recesses 13 can be counted by observing the main surface of the metal sheet 10 with an optical microscope, displaying it in 3D, and counting the portion of the metal sheet 10 that is half or less of its thickness.

[0054] The metal sheet 10 may contain one or more metals selected from the group consisting of copper, nickel, aluminum, gold, silver, tin, and chromium. The metal sheet 10 may be made of these pure metals or an alloy. Alternatively, the surface of one of these metals may be plated with another metal. This allows the metal sheet 10 to be suitable for a variety of applications. By selecting the appropriate material, the metal sheet 10 can be used as, for example, a battery current collector, an electromagnetic wave shield, a filter, a catalyst carrier, and the like.

[0055] The metal sheet 10 may have a surface containing tin and an interior containing copper. Such a metal sheet 10 can be obtained, for example, by plating the surface of a copper metal sheet 10 with tin. The tin plating method is not particularly limited, and any known method may be appropriately adopted. By including tin on the surface, self-discharge can be suppressed when the metal sheet 10 is used, for example, as a current collector for a nickel-zinc battery. Furthermore, since the interior contains copper, the electrical resistance of the metal sheet 10 can be reduced.

[0056] Furthermore, the metal sheet 10 may have a strut portion 11 and a node portion 12 each having a surface and an interior portion covered by the surface, the surface containing tin, and the interior portion containing copper. Such a metal sheet 10 can be obtained, for example, by tin-plating a copper porous metal body having a skeleton with a three-dimensional mesh structure, followed by rolling. The tin-plating method is not particularly limited, and any known method may be used as appropriate. Such a metal sheet 10 is also suitable as a current collector for a nickel-zinc battery.

[0057] <Battery, Nickel-Zinc Battery> A battery according to an embodiment of the present disclosure includes the metal sheet 10 according to the embodiment of the present disclosure as a current collector. A nickel-zinc battery according to an embodiment of the present disclosure includes the metal sheet 10 according to the embodiment of the present disclosure as a current collector. As described above, the metal sheet 10 can be used as a current collector suitable for various batteries by appropriately selecting the material (metal type) of the metal sheet 10 or plating the surface of the metal sheet 10 with an appropriately selected metal. Furthermore, the metal sheet 10 has high active material retention due to the through holes 14 and recesses 13, making it suitable for use as a current collector. In particular, as described above, a metal sheet 10 whose surface contains tin can suppress self-discharge and be suitable for use as a current collector in a nickel-zinc battery. The nickel-zinc battery according to an embodiment of the present disclosure is not particularly limited in terms of configuration other than the current collector, and known configurations can be adopted.

[0058] <Method for manufacturing metal sheet> A method for manufacturing a metal sheet according to an embodiment of the present disclosure includes the steps of preparing a porous metal body (hereinafter also simply referred to as "porous metal body") having a skeleton with a three-dimensional network structure, and rolling the porous metal body in the thickness direction. Figure 8 shows an outline of an example of a method for manufacturing a metal sheet according to an embodiment of the present disclosure. As shown in Figure 8, a porous metal body 20 is prepared that is flat and has a skeleton 21 with a three-dimensional network structure. Figure 9 shows an electron microscope photograph of a cross section of the porous metal body 20.

[0059] (Step of Preparing a Metal Porous Body) As the metal porous body 20 having a skeleton 21 with a three-dimensional network structure, nickel-Celmet (Celmet is a registered trademark), aluminum-Celmet (Aluminum-Celmet is a registered trademark), copper-Celmet, and the like, manufactured by Sumitomo Electric Industries, Ltd. To prepare a metal porous body 20 made of a material other than nickel, aluminum, or copper, the following procedure can be used: First, the surface of the skeleton of urethane foam is made conductive, then the surface of the skeleton is plated with the desired metal, and then the urethane foam is removed by burning.

[0060] (Step of Rolling the Porous Metal Body in the Thickness Direction) The porous metal body 20 prepared as described above can be rolled in the thickness direction using, for example, a roller press to obtain a metal sheet 10 according to an embodiment of the present disclosure. The number of times the roller press is applied is not particularly limited, and multiple roll presses may be performed to obtain a metal sheet 10 of the desired thickness. As a result, the skeleton 21 of the porous metal body 20 is compressed in the thickness direction, forming rod- or plate-shaped strut portions 11. Furthermore, the branched portions of the skeleton 21 become node portions 12. Because the skeleton 21 of the porous metal body 20 before rolling forms a three-dimensional network structure, the metal sheet 10 formed after rolling includes portions in which multiple strut portions 11 at twisted positions are stacked in the thickness direction. The surface of the metal sheet 10 manufactured as shown in FIG. 8 may also be plated with another metal. In this case, the number of recesses 13 and through holes 14 in the metal sheet can be adjusted by adjusting the film thickness of the plated metal. This also allows the manufacture of a metal sheet 10 in which the metal type differs between the surface and the interior of the metal sheet 10. Alternatively, the surface of the skeleton 21 of the porous metal body 20 may be plated with another metal before rolling. This makes it possible to produce a metal sheet 10 in which the metal types on the surfaces and inside of the strut portions 11 and node portions 12 are different.

[0061] The present disclosure will be described in more detail below based on examples, but these examples are merely illustrative and the porous metal bodies of the present disclosure are not limited to these. The scope of the present disclosure is defined by the claims, and includes all modifications within the meaning and scope of the claims.

[0062] [Example 1] As the metal porous body 20, a copper Celmet (manufactured by Sumitomo Electric Industries, Ltd., product number: #6, number of cells: 40 to 53, average pore diameter: 540 μm, average window diameter: 270 μm, specific surface area: 2800 m) was used. ２ / m ２A porous metal body 20 having a thickness of 1000 μm was prepared. The porous metal body 20 was rolled using a roller press to obtain a metal sheet 10 having a thickness of 60 μm. The surface of the metal sheet 10 was plated with tin so that the thickness of the plating film 16 was 3 μm. The tin plating was carried out using a methanesulfonic acid tin plating bath. The results of observing the surface and interior of the obtained metal sheet 10 are shown in FIGS. 1 to 7.

[0063] [Example 2] A metal sheet 10 was produced in the same manner as in Example 1, except that tin plating was carried out to a thickness of 14 μm. The results of observing the surface and interior of the obtained metal sheet 10 are shown in Figures 10 to 13. As shown in Figure 13, a thick tin plating film 16 was formed on the surface of the metal sheet 10 obtained in Example 2.

[0064] Comparative Example 1 A copper perforated metal 30 (copper foil etching material manufactured by Taiyo Wire Mesh Co., Ltd.) having openings 31 was prepared. This perforated metal 30 was plated with tin so that the thickness of the plating film 16 became 3 μm. The tin plating conditions were the same as in Example 1. The appearance and cross section of the perforated metal 30 were observed with a scanning electron microscope, and the results are shown in FIGS. 14 to 16 .

[0065] Comparative Example 2 The porous metal body 20 (copper Celmet) prepared in Example 1 was plated with tin so that the thickness of the plating film 16 was 3 μm. The tin plating conditions were the same as in Example 1.

[0066] <Evaluation> (Appearance) The metal sheets 10 obtained in Examples 1 and 2 were observed with a scanning electron microscope, and the measured values ​​are shown in Tables 1 and 2.

[0067]

[0068]

[0069] (Active Material Retention) To evaluate the active material retention, the following three types of active materials, A to C, were prepared with different viscosities by varying the solid content ratio. The active materials were composed of zinc oxide, acetylene black, and binder in a 90:5:5 weight ratio after drying. The slurry was prepared using a 0.5% by mass CMC (carboxymethyl cellulose) aqueous solution. Active Material A (high viscosity): 61% solid content. Active Material B (medium viscosity): 56% solid content. Active Material C (low viscosity): 49% solid content. Each active material was then applied to the metal sheets of Examples 1 and 2, the punched metal of Comparative Example 1, and the porous metal of Comparative Example 2, and the extent to which the active material could be retained was evaluated. The results are shown in Table 3. In Table 3, a rating of "high" indicates that a sufficient amount of active material was retained without flowing out, and a rating of "low" indicates that the active material flowed out or could not be filled into the openings, resulting in insufficient retention.

[0070]

[0071] As shown in Table 3, the metal sheet 10 according to the embodiment of the present disclosure has through holes 14 with complex shapes and is thin, so it can hold a sufficient amount of active material of any viscosity.

[0072] 10: Metal sheet, 11: Strut portion, 12: Node portion, 13: Recess, 14: Through hole, 15: Independent space, 16: Plated film, 20: Metal porous body, 21: Skeleton, 30: Punched metal, 31: Opening

Claims

1. A flat metal sheet having a main surface located on one side in a thickness direction, The strut section has a plurality of strut sections and a node section where ends of the plurality of strut sections are connected to each other, a network structure is formed by the strut portions and the node portions, and a plurality of the strut portions are in close contact with each other; A plurality of through holes penetrating the main surface in a thickness direction, Metal sheet.

2. The metal sheet of claim 1 , wherein the struts are strip-shaped.

3. 3. The metal sheet of claim 1, wherein a plurality of the strut portions in a twisted position are layered.

4. The metal sheet according to claim 1 or 2, wherein the through holes have a diameter that is not constant in the thickness direction of the metal sheet.

5. The metal sheet according to claim 1 or 2, wherein the through holes have a diameter of 1 μm or more and 900 μm or less on the main surface.

6. The metal sheet according to claim 1 or 2, wherein the number of the through holes is 250 or more and 2500 or less per 500 μm square on the main surface.

7. 3. The metal sheet according to claim 1, wherein the opening ratio is 10% or more and 40% or less.

8. the metal sheet has a surface and an interior; The surface includes the main surface, a back surface located opposite the main surface, and an outer peripheral surface of the metal sheet, the interior is covered by the surface, The metal sheet according to claim 1 or 2, wherein the metal sheet has an independent space in the interior surrounded by the strut portions and the node portions.

9. The metal sheet according to claim 1 or 2, wherein three or more strut portions are connected to the node portion.

10. 3. The metal sheet according to claim 1, wherein the strut portion has a thickness of 1 μm or more and 10 μm or less.

11. 3. The metal sheet according to claim 1, wherein the strut portion has a length of 50 μm or more and 500 μm or less.

12. 3. The metal sheet according to claim 1, wherein the strut portion has a width of 100 μm or more and 3000 μm or less.

13. The metal sheet according to claim 1 or 2, wherein the strut portion includes a portion where two or more layers and five or less layers are laminated in the thickness direction of the metal sheet.

14. The metal sheet according to claim 1 or 2, wherein the thickness of the metal sheet is 10 μm or more and 100 μm or less.

15. The metal sheet according to claim 1 or 2, wherein the metal sheet has a plurality of recesses on the main surface.

16. The metal sheet according to claim 15 , wherein the recess has a diameter of 1 μm or more and 900 μm or less on the main surface.

17. The metal sheet according to claim 15 , wherein the recess has a diameter that is not constant in the thickness direction of the metal sheet.

18. The metal sheet according to claim 15, wherein the number of the recesses is 75 to 750 per 500 μm square on the main surface.

19. 3. The metal sheet according to claim 1 or claim 2, comprising at least one selected from the group consisting of copper, nickel, aluminum, gold, silver, tin, and chromium.

20. the surface comprises tin; 9. The metal sheet of claim 8, wherein the inner portion comprises copper.

21. the strut portion and the node portion have a surface and an interior portion covered by the surface; the surface comprises tin; 3. The metal sheet of claim 1 or claim 2, wherein the inner portion comprises copper.

22. A battery comprising the metal sheet according to claim 1 or 2 as a current collector.

23. A nickel-zinc battery comprising the metal sheet of claim 20 as a current collector.

24. A step of preparing a flat metal porous body having a skeleton with a three-dimensional network structure; a step of rolling the metal porous body in a thickness direction to produce the metal sheet according to claim 1; having Methods for manufacturing metal sheets.