Precoated metal plate and method for producing precoated methal plate

Abstract

Provided is a precoated metal plate (1), in which a second exposed part (30B) is disposed directly behind a first exposed part (30A), and a first length (L1) of the first exposed part (30A) from an end surface (15) of a metal substrate (10) to an edge part (21A) of a first coating film part (20A) is equal to or greater than a second length (L2) of a second exposed part (30B) from the end surface (15) of the metal substrate (10) to an edge part (21B) of a second coating film part (20B) disposed directly behind the first exposed part (30A).

Description

Pre-coated metal sheet and method for manufacturing the same

[0001] The present disclosure relates to a pre-coated metal sheet and a method for manufacturing the same.

[0002] A container body in the form of a cylindrical body is formed by subjecting a metal substrate to forming processing, and a container is manufactured by joining the container body to a lid plate and a bottom plate. As a container for a battery, a container provided with a resin film on its surface is used. By providing a resin film on the surface of the container, the insulation and corrosion resistance of the container can be enhanced.

[0003] However, when attempting to perform joining while a resin film is provided at the joint portion on the surface of the metal substrate, there is a possibility of causing welding defects due to the influence of the resin film present at the joint portion. Also, the resin film may be thermally decomposed by welding, and the insulation and corrosion resistance of the resin film around the joint portion may be impaired.

[0004] In Patent Document 1, a method for manufacturing a power storage element is described. In the method of Patent Document 1, after forming an insulating film by performing insulating painting on the outer surfaces of the formed container body and lid body, the insulating film is removed by irradiating the insulating film on the outer surfaces of the container body and lid body with laser light. Then, after exposing the metal surfaces of the container body and lid body, the metal surfaces of both are joined together. According to Patent Document 1, a container can be manufactured by joining the exposed metal surfaces together, but it is necessary to perform a step of removing the insulating film at the joint portion, resulting in a decrease in production efficiency.

[0005] In Patent Document 2, a laminated composite container is described that includes a lid material made of an aluminum material with a synthetic resin layer installed on its inner surface and a composite container body made of an aluminum material with a synthetic resin layer installed on its inner surface. In Patent Document 2, a laminated composite container is manufactured by joining aluminum materials together and synthetic resin layers together. In Patent Document 2, it is described that after painting the synthetic resin layer on the aluminum material smaller by the amount of the aluminum joint portion, the composite container body is manufactured by forming processing. Then, the composite container body and the lid material are overlapped so that the aluminum materials contact each other, and the aluminum materials at the aluminum joint portion are joined together.

[0006] Patent Document 2 describes a method for manufacturing a container with a corrosion-resistant resin coating, in which an aluminum material (pre-coated metal sheet) is manufactured in advance, which has exposed metal parts where the aluminum material is exposed without a resin coating. By joining a lid material formed from such a pre-coated metal sheet with exposed metal parts to the composite container body, the step of removing the resin coating from the joining area before joining the container is eliminated.

[0007] Japanese Patent Publication No. 2015-035265 Japanese Patent Publication No. 1998-324335

[0008] In Patent Document 2, a metal exposed portion and a resin coating are formed on the inner surfaces of both the lid material and the composite container body, and the lid material is placed on the composite container body so that the aluminum materials of the two aluminum joints overlap, and the joints are then joined. In Patent Document 2, corrosion resistance can be imparted to the aluminum material by providing a resin coating on the inner surface of the container. As containers are used for a variety of purposes, there is a growing demand for containers with high functionality, and there is a growing need for the manufacture of containers with resin coatings on both the inner and outer surfaces.

[0009] This disclosure has been made in view of the problems of the prior art. The object of this disclosure is to provide a pre-coated metal sheet and a method for manufacturing a pre-coated metal sheet that can protect both sides of a metal substrate and can improve the productivity of a joint formed by joining pre-coated metal sheets.

[0010] A pre-coated metal sheet according to a first aspect of the present disclosure comprises a plate-shaped metal substrate, a first coating portion including a first resin coating provided on a first surface which is one side of the metal substrate, and a second coating portion including a second resin coating provided on a second surface which is the side of the metal substrate opposite to the first surface. A first exposed portion is provided on at least a part of the peripheral edge of the first surface of the metal substrate, from the edge of the first coating portion to the end face of the metal substrate. A second exposed portion is provided on at least a part of the peripheral edge of the second surface of the metal substrate, from the edge of the second coating portion to the end face of the metal substrate. The second exposed portion is located directly behind the first exposed portion. The first length of the first exposed portion from the end face of the metal substrate to the edge of the first coating portion is equal to or greater than the second length of the second exposed portion from the end face of the metal substrate to the edge of the second coating portion located directly behind the first exposed portion.

[0011] A method for manufacturing a pre-coated metal sheet according to a second aspect of the present disclosure is a method for manufacturing a pre-coated metal sheet. The pre-coated metal sheet comprises a metal substrate in the shape of a sheet, a first coating portion provided on a first surface which is one side of the metal substrate and includes a first resin coating, and a second coating portion provided on a second surface which is the side of the metal substrate opposite to the first surface and includes a second resin coating. The method for manufacturing a pre-coated metal sheet includes a first coating step of applying a first paint to the first surface of the metal substrate to form a first coating portion including a first resin coating, and forming a first exposed portion on the peripheral edge of the metal substrate in contact with the first coating portion. The method for manufacturing a pre-coated metal sheet includes a second coating step of applying a second paint to the second surface of the metal substrate to form a second coating portion including a second resin coating, and forming a second exposed portion on the peripheral edge of the metal substrate in contact with the second coating portion. In the first painting step, the first coating portion and the first exposed portion are formed such that the first exposed portion, which extends from the edge of the first coating portion to the end face of the metal substrate, is provided on at least a portion of the peripheral edge of the first surface of the metal substrate. In the second painting step, the second coating portion and the second exposed portion are formed such that the second exposed portion, which extends from the edge of the second coating portion to the end face of the metal substrate, is provided on at least a portion of the peripheral edge of the second surface of the metal substrate, and the second exposed portion is positioned directly behind the first exposed portion. In the first and second painting steps, the first paint and the second paint are applied such that the first length of the first exposed portion, from the end face of the metal substrate to the edge of the first coating portion, is equal to or greater than the second length of the second exposed portion, from the end face of the metal substrate to the edge of the second coating portion.

[0012] According to this disclosure, it is possible to provide a pre-coated metal sheet and a method for manufacturing a pre-coated metal sheet that can protect both sides of a metal substrate and improve the productivity of a joint formed by joining pre-coated metal sheets.

[0013] Figure 1 is a front view showing an example of a pre-coated metal sheet according to one embodiment. Figure 2 is a top view showing an example of a pre-coated metal sheet according to one embodiment. Figure 3 is a bottom view showing an example of a pre-coated metal sheet according to one embodiment. Figure 4 is a perspective view showing an example of a pre-coated metal sheet processed into a cylindrical shape in the processing step. Figure 5 is a cross-sectional view showing an example of a pre-coated metal sheet processed into a cylindrical shape in the processing step. Figure 6 is a perspective view showing an example of a pre-coated metal sheet processed into a cylindrical shape after being joined in the joining step. Figure 7 is a cross-sectional view showing an example of a pre-coated metal sheet processed into a cylindrical shape after being joined in the joining step. Figure 8 is a perspective view showing an example of a pre-coated metal sheet processed into an L-shape in the processing step. Figure 9 is a cross-sectional view showing an example of a pre-coated metal sheet processed into an L-shape in the processing step. Figure 10 is a perspective view showing an example of a pre-coated metal sheet processed into an L-shape after being joined in the joining step. Figure 11 is a cross-sectional view showing an example of a pre-coated metal sheet processed into an L-shape after being joined in the joining step. Figure 12 is a perspective view showing another example of a pre-coated metal sheet processed into an L-shape during the manufacturing process. Figure 13 is a cross-sectional view showing another example of a pre-coated metal sheet processed into an L-shape during the manufacturing process. Figure 14 is a perspective view showing another example of a pre-coated metal sheet processed into an L-shape after being joined in the joining process. Figure 15 is a cross-sectional view showing another example of a pre-coated metal sheet processed into an L-shape after being joined in the joining process. Figure 16 is a perspective view showing an example of a state before the plate material is joined to the cylindrical body. Figure 17 is a cross-sectional view showing an example of a state before the plate material is joined to the cylindrical body. Figure 18 is a perspective view showing an example of a state after the plate material is joined to the cylindrical body. Figure 19 is a cross-sectional view showing an example of a state after the plate material is joined to the cylindrical body.

[0014] The pre-coated metal sheets and joints according to this embodiment, as well as the manufacturing methods thereof, will be described in detail below with reference to the drawings. This disclosure is not limited to the following embodiments. Furthermore, some or all of the components in the embodiments can be combined as appropriate. Note that the dimensional ratios in the drawings are exaggerated for illustrative purposes and may differ from the actual ratios. In addition, multiple identical or similar components are described using reference numerals with branch numbers to distinguish them, but when components with branch numbers are not particularly distinguished, they may be described collectively using reference numerals without branch numbers. For example, in the embodiments of Figures 4 to 7, branch number a may be used for description; in the embodiments of Figures 8 to 11, branch number b may be used for description; in the embodiments of Figures 12 to 15, branch number c may be used for description; and in the embodiments of Figures 16 to 19, branch number d may be used for description.

[0015] [1. Pre-coated metal sheet] First, the pre-coated metal sheet 1 according to this embodiment will be described. In this embodiment, the pre-coated metal sheet 1 is rectangular (square) when viewed from the thickness direction. However, the shape of the pre-coated metal sheet 1 is not limited to a square shape, and may be a polygon such as a circle, ellipse, triangle, teardrop shape, or irregular shape. As shown in Figures 1 to 3, the pre-coated metal sheet 1 according to this embodiment comprises a metal substrate 10 and a coating portion 20.

[0016] The metal substrate 10 is in the shape of a plate. The thickness of the metal substrate 10 may be 0.1 mm or more and 10 mm or less. When the thickness of the metal substrate 10 is 0.1 mm or more, the rigidity of the pre-coated metal sheet 1 can be improved. When the thickness of the metal substrate 10 is 10 mm or less, the processability of the pre-coated metal sheet 1 can be improved. The thickness of the metal substrate 10 may be 0.3 mm or more, or 0.6 mm or more. In addition, the thickness of the metal substrate 10 may be 5 mm or less, 2 mm or less, 1 mm or less, or 0.8 mm or less.

[0017] In this embodiment, the metal substrate 10 is rectangular in shape when viewed from the thickness direction. The metal substrate 10 has a first pair of sides 11 and a second pair of sides 12. The second pair of sides 12 intersect and face the first pair of sides 11. The first pair of sides 11 includes a first short side 11A and a second short side 11B. The second pair of sides 12 includes a first long side 12A and a second long side 12B. The first short side 11A and the second short side 11B are shorter than the first long side 12A and the second long side 12B. In this embodiment, the second pair of sides 12 are longer than the first pair of sides 11. However, the first pair of sides 11 may be longer than the second pair of sides 12. Also, the first pair of sides 11 and the second pair of sides 12 may be the same length or may be different lengths.

[0018] The metal substrate 10 may contain at least one metal selected from the group consisting of aluminum, copper, iron, magnesium, titanium, and alloys containing these metals. These metals have high strength and excellent durability. Therefore, they are suitable for various applications, including, for example, battery containers.

[0019] The metal substrate 10 may contain aluminum. The aluminum may be pure aluminum or an aluminum alloy. The aluminum content of pure aluminum may be 99.00% by mass or more, 99.50% by mass or more, or 99.80% by mass or more. The aluminum alloy contains aluminum and elements other than aluminum. The elements other than aluminum contained in the aluminum alloy may include one or more of the following elements: silicon (Si), iron (Fe), copper (Cu), manganese (Mn), magnesium (Mg), chromium (Cr), zinc (Zn), titanium (Ti), vanadium (V), gallium (Ga), nickel (Ni), boron (B), zirconium (Zr), etc. The total content of elements other than aluminum contained in the aluminum alloy may exceed 1% by mass. The total content of elements other than aluminum contained in the aluminum alloy may be 10% by mass or less, or 5% by mass or less. The content of each element other than aluminum contained in the aluminum alloy may be 10% by mass or less, or 1% by mass or less. The aluminum alloy may be a 1000 series alloy, a 3000 series alloy, or a 5000 series alloy as defined in JIS H4000. The aluminum alloy may also include at least one selected from the group consisting of A1050, A1070, A1100, A3003, A3004, and A5052 as defined in JIS H4000.

[0020] The coating portion 20 is provided on at least one surface of the metal substrate 10. The coating portion 20 is provided on both sides of the metal substrate 10. Specifically, as shown in Figures 1 to 3, the metal substrate 10 has a first surface 13, which is one surface, and a second surface 14, which is the surface opposite to the first surface 13. The coating portion 20 includes a first coating portion 20A and a second coating portion 20B. The first coating portion 20A is provided on the first surface 13, which is one surface of the metal substrate 10. The second coating portion 20B is provided on the second surface 14, which is the surface opposite to the first surface 13 of the metal substrate 10.

[0021] An exposed portion 30 is provided on at least a part of the peripheral edge 16 on at least one surface of the metal substrate 10. The exposed portion 30 is the portion of the metal substrate 10 that is exposed. In the exposed portion 30, the metal substrate 10 is exposed from the edge 21 of the coating portion 20 to the end face 15 of the metal substrate 10. The exposed portion 30 includes a first exposed portion 30A and a second exposed portion 30B.

[0022] A first exposed portion 30A is provided on at least a part of the peripheral edge 16 of the first surface 13 of the metal substrate 10. The first exposed portion 30A is the portion of the metal substrate 10 that is exposed from the edge 21A of the first coating portion 20A to the end face 15 of the metal substrate 10. The first exposed portion 30A is the portion of the first surface 13 of the metal substrate 10 that is not coated by the first coating portion 20A.

[0023] A second exposed portion 30B is provided on at least a part of the peripheral edge 16 of the second surface 14 of the metal substrate 10. The second exposed portion 30B is the portion of the metal substrate 10 that is exposed from the edge 21B of the second coating portion 20B to the end face 15 of the metal substrate 10. The second exposed portion 30B is the portion of the second surface 14 of the metal substrate 10 that is not coated by the second coating portion 20B.

[0024] In the pre-coated metal sheet 1 according to this embodiment, the exposed portion 30 is provided around the entire circumference of the metal substrate 10. However, it is sufficient if the exposed portion 30 is provided on at least a part of the peripheral edge 16 on the surface of the metal substrate 10. For example, the exposed portion 30 may be provided on the peripheral edge 16 of at least one of the first pair of sides 11 and the second pair of sides 12. Specifically, the exposed portion 30 may be provided on the peripheral edge 16 of at least one side selected from the group consisting of the first short side 11A, the second short side 11B, the first long side 12A, and the second long side 12B.

[0025] In this embodiment, the second exposed portion 30B is located directly behind the first exposed portion 30A. Therefore, both sides of the metal substrate 10 at the peripheral edge 16 of at least one side are exposed. In this embodiment, the first exposed portion 30A and the second exposed portion 30B are located on the peripheral edge 16 of all sides of the metal substrate 10. That is, the first exposed portion 30A and the second exposed portion 30B are located on the peripheral edge 16 of the first short side 11A, the second short side 11B, the first long side 12A, and the second long side 12B of the metal substrate 10. However, the first exposed portion 30A and the second exposed portion 30B may be located on the peripheral edge 16 of at least one side of the metal substrate 10. For example, the first exposed portion 30A and the second exposed portion 30B are arranged on the peripheral edge 16 of at least one side selected from the group consisting of the first short side 11A, the second short side 11B, the first long side 12A, and the second long side 12B of the metal substrate 10.

[0026] The first length L1 of the first exposed portion 30A, from the end face 15 of the metal substrate 10 to the edge 21A of the first coating portion 20A, is greater than or equal to the second length L2 of the second exposed portion 30B, from the end face 15 of the metal substrate 10 to the edge 21B of the second coating portion 20B, which is located directly behind the first exposed portion 30A. This reduces the impact of welding on the first coating portion 20A when supplying welding energy from the first surface 13 side, as will be described later. Furthermore, on the second surface 14, the area protected by the second coating portion 20B over the metal substrate 10 can be expanded. The first length L1 may be greater than the second length L2. For example, the second length L2 may be 0.5 times or more and 1 time less than the first length L1, 0.6 times or more and less than 1 time, 0.7 times or more and less than 1 time, 0.8 times or more and less than 1 time, 0.9 times or more and less than 1 time, 0.5 times or more and 0.9 times or less, 0.5 times or more and 0.8 times or less, 0.5 times or more and 0.7 times or less, or 0.5 times or more and 0.6 times or less.

[0027] At least one of the first length L1 and the second length L2 may be 1 mm or more and 10 mm or less. If the first length L1 is 1 mm or more, the adverse effects of welding to the first resin coating of the first coated portion 20A adjacent to the first exposed portion 30A can be reduced. If the second length L2 is 1 mm or more, the adverse effects of welding to the second resin coating of the second coated portion 20B adjacent to the second exposed portion 30B can be reduced. If the first length L1 is 10 mm or less, the peripheral edge 16 of the metal substrate 10 can be protected by the first resin coating of the first coated portion 20A adjacent to the first exposed portion 30A. If the second length L2 is 10 mm or less, the peripheral edge 16 of the metal substrate 10 can be protected by the second resin coating of the second coated portion 20B adjacent to the second exposed portion 30B. The first length L1 or the second length L2 may be 2 mm or more, or 3 mm or more. Furthermore, the first length L1 or the second length L2 may be 7 mm or less, or 5 mm or less.

[0028] The coating portion 20 includes a resin coating. The coating portion 20 may include a first coating portion 20A and a second coating portion 20B. The first coating portion 20A includes a first resin coating. The second coating portion 20B includes a second resin coating. By including a resin coating in the coating portion 20, the corrosion resistance of the pre-coated metal plate 1 can be improved.

[0029] The first resin coating may be insulating. The second resin coating may also be insulating. The pre-coated metal plate 1 may be a pre-coated metal plate for a battery container. The dielectric breakdown voltage of at least one of the first and second resin coatings is preferably 3kV or more and 20kV or less, and preferably 5kV or more and 15kV or less. If the dielectric breakdown voltage of the first resin coating is 3kV or more and 20kV or less, for example, if the pre-coated metal plate 1 is used as a battery container and the batteries are stacked, it is possible to suppress short circuits in the batteries even if the electrolyte leaks out for some reason. If the dielectric breakdown voltage of the second resin coating is 3kV or more and 20kV or less, the insulation between the battery container and the power generation element can be improved. The dielectric breakdown voltage can be obtained by applying an AC voltage that increases at a constant rate between the first or second resin coating and the metal substrate 10, in accordance with "4. Dielectric Breakdown Test Method" of JIS H8687:2013, and measuring the voltage at the point when the first or second resin coating undergoes dielectric breakdown. The dielectric breakdown voltage can be measured, for example, using the Instec GPT-9000 / 9000A series (model: GPT-9803) from Texio Technology Co., Ltd.

[0030] At least one of the first resin coating and the second resin coating may contain at least one resin selected from the group consisting of acrylic resin, polyester resin, polyurethane resin, epoxy resin, phenolic resin, fluororesin, silicone resin, and organic-inorganic hybrid resin. Among these, at least one of the first resin coating and the second resin coating is preferably an acrylic resin, polyester resin, polyurethane resin, or epoxy resin. The acrylic resin is a resin obtained by polymerizing at least one of acrylic monomer and methacrylic monomer, and optionally monomers other than acrylic monomer and methacrylic monomer. The first resin coating and the second resin coating may contain inorganic additives such as ceramics and titanium dioxide. The same applies to other resins; for example, polyester resin may contain resin components other than polyester. Furthermore, the materials of the first resin coating and the second resin coating may be the same or different.

[0031] The thickness of the first resin coating may be 5 μm or more and 1000 μm or less. The thickness of the second resin coating may also be 5 μm or more and 1000 μm or less. When the thickness of the first or second resin coating is 5 μm or more, the wear resistance of the pre-coated metal sheet 1 can be improved. When the thickness of the first or second resin coating is 1000 μm or less, the productivity of the pre-coated metal sheet 1 can be improved. The thickness of the first or second resin coating may be 20 μm or more, 50 μm or more, or 100 μm or more, respectively. The thickness of the first or second resin coating may be 500 μm or less, 300 μm or less, or 200 μm or less, respectively.

[0032] [2. Method for Manufacturing Pre-Coated Metal Sheets] Next, a method for manufacturing the pre-coated metal sheet 1 according to this embodiment will be described. The method for manufacturing the pre-coated metal sheet 1 includes a painting step. Then, a pre-coated metal sheet 1 as shown in Figures 1 to 3 can be manufactured.

[0033] (Painting Process) The painting process involves applying paint to at least one surface of the metal substrate 10 to form a painted portion 20 including a resin film, and forming an exposed portion 30 on the peripheral edge 16 of the metal substrate 10 in contact with the painted portion 20. In the painting process of this embodiment, paint is applied to both the first surface 13 and the second surface 14 of the metal substrate 10. The metal substrate 10 may be pre-treated before applying paint to its surface. The painting process includes a first painting process and a second painting process. The first painting process involves applying a first paint to the first surface 13 of the metal substrate 10 to form a first painted portion 20A including a first resin film, and forming a first exposed portion 30A on the peripheral edge 16 of the metal substrate 10 in contact with the first painted portion 20A. The second painting process involves applying a second paint to the second surface 14 of the metal substrate 10 to form a second coating portion 20B including a second resin film, and forming a second exposed portion 30B on the peripheral edge 16 of the metal substrate 10 in contact with the second coating portion 20B.

[0034] In the painting process, an exposed portion 30 extending from the edge 21 of the painted portion 20 to the end face 15 of the metal substrate 10 is provided on at least a part of the peripheral edge 16 on the surface of the metal substrate 10. Specifically, in the first painting process, the first painted portion 20A and the first exposed portion 30A are formed such that the first exposed portion 30A extending from the edge 21A of the first painted portion 20A to the end face 15 of the metal substrate 10 is provided on at least a part of the peripheral edge 16 on the first surface 13 of the metal substrate 10. Furthermore, in the second painting process, a second exposed portion 30B extending from the edge 21B of the second painted portion 20B to the end face 15 of the metal substrate 10 is provided on at least a part of the peripheral edge 16 on the second surface 14 of the metal substrate 10. The second painted portion 20B and the second exposed portion 30B are formed such that the second exposed portion 30B is positioned directly behind the first exposed portion 30A.

[0035] In the first and second painting processes, the first and second coatings are applied such that the first length L1 of the first exposed portion 30A, from the end face 15 of the metal substrate 10 to the edge 21A of the first coating portion 20A, is equal to or greater than the second length L2 of the second exposed portion 30B, from the end face 15 of the metal substrate 10 to the edge 21B of the second coating portion 20B.

[0036] The first coating is not particularly limited as long as it is a material capable of forming a first resin film. Similarly, the second coating is not particularly limited as long as it is a material capable of forming a second resin film. At least one of the first and second coatings may include acrylic resin coatings, polyester resin coatings, polyurethane coatings, epoxy resin coatings, phenolic resin coatings, fluororesin coatings, silicone resin coatings, or organic-inorganic hybrid coatings. Among these, acrylic resin coatings, polyester resin coatings, polyurethane coatings, or epoxy resin coatings are preferred. Note that acrylic resin coatings are coatings made using a resin obtained by polymerizing a derivative of acrylic acid or methacrylic acid as a coating-forming element. The materials of the first and second coatings may be the same or different.

[0037] As a method for forming the first exposed portion 30A or the second exposed portion 30B, for example, the portions of the metal substrate 10 corresponding to the first exposed portion 30A and the second exposed portion 30B may be masked with a release agent, release paper, or release tape. Then, after forming the first coated portion 20A and the second coated portion 20B, the masking may be removed to peel off the first coated portion 20A and the second coated portion 20B that were formed on the surface of the portion where the first exposed portion 30A and the second exposed portion 30B are formed, via the masking. Alternatively, the first and second coatings may be applied only to the areas where the first and second coated portions 20A and the second exposed portion 20B of the metal substrate 10 are formed, and the first and second coatings may not be applied to the areas where the first exposed portion 30A and the second exposed portion 30B are formed.

[0038] The method for applying the first and second coatings to the surface of the metal substrate 10 is not particularly limited. The method for applying the first and second coatings to the surface of the metal substrate 10 may include at least one of a coating method and a printing method. The coating method may include at least one selected from the group consisting of roll coating, spray coating, bar coating, dipping, electrostatic coating, powder coating, electrodeposition coating, and brush coating. The printing method may include at least one selected from the group consisting of gravure printing, reverse gravure printing, offset printing, flexographic printing, and screen printing.

[0039] After applying the first and second coatings to the surface of the metal substrate 10, a drying treatment may be performed as needed to remove the dispersed solvent in the first and second coatings. The drying treatment may be natural drying, drying by air blowing, drying using an oven, or a combination thereof. The drying conditions are not particularly limited as long as the dispersed solvent is removed, and heat treatment may be performed as needed.

[0040] When a thermal polymerization initiator is used as the polymerization initiator, the first and second coatings can be cured by heating them after applying them to the surface of the metal substrate 10. The heating conditions are not particularly limited and should be such that the first and second coatings can be cured and perform their functions.

[0041] When a photopolymerization initiator is used as the polymerization initiator, the first and second coatings may be applied to the surface of the metal substrate 10, and then cured by irradiation with active energy rays. At least one of ultraviolet rays, electron beams, X-rays, infrared rays, and visible light can be used as the active energy rays irradiated when curing the first and second coatings. Of these active energy rays, ultraviolet rays are preferred from the viewpoint of curability and prevention of resin degradation.

[0042] When curing the first and second coatings with ultraviolet light, various ultraviolet irradiation devices can be used. Examples of ultraviolet irradiation devices include xenon lamps, high-pressure mercury lamps, and metal halide lamps. The ultraviolet irradiation conditions are not particularly limited; any conditions that allow the first and second coatings to cure and function are acceptable.

[0043] <Effects> As described above, the pre-coated metal plate 1 according to this embodiment comprises a plate-shaped metal substrate 10 and a first coating portion 20A provided on a first surface 13, which is one surface of the metal substrate 10, and including a first resin coating. The pre-coated metal plate 1 comprises a second coating portion 20B provided on a second surface 14, which is the surface of the metal substrate 10 opposite to the first surface 13, and including a second resin coating. A first exposed portion 30A is provided on at least a part of the peripheral edge 16 of the first surface 13 of the metal substrate 10, from the edge 21A of the first coating portion 20A to the end surface 15 of the metal substrate 10. A second exposed portion 30B is provided on at least a part of the peripheral edge 16 of the second surface 14 of the metal substrate 10, from the edge 21B of the second coating portion 20B to the end surface 15 of the metal substrate 10. The second exposed portion 30B is located directly behind the first exposed portion 30A. The first length L1 of the first exposed portion 30A, from the end face 15 of the metal substrate 10 to the edge 21A of the first coating portion 20A, is greater than or equal to the second length L2 of the second exposed portion 30B, from the end face 15 of the metal substrate 10 to the edge 21B of the second coating portion 20B, which is located directly behind the first exposed portion 30A.

[0044] Further, the manufacturing method of the pre-coated metal sheet 1 includes a first coating step of coating a first paint on the first surface 13 of the metal base material 10 to form a first coating film portion 20A including a first resin film, and forming a first exposed portion 30A on the peripheral portion 16 of the metal base material 10 in contact with the first coating film portion 20A. The manufacturing method of the pre-coated metal sheet 1 includes a second coating step of coating a second paint on the second surface 14 of the metal base material 10 to form a second coating film portion 20B including a second resin film, and forming a second exposed portion 30B on the peripheral portion 16 of the metal base material 10 in contact with the second coating film portion 20B. In the first coating step, the first coating film portion 20A and the first exposed portion 30A are formed such that the first exposed portion 30A exposed from the edge portion 21A of the first coating film portion 20A to the end surface 15 of the metal base material 10 is provided on at least a part of the peripheral portion 16 of the first surface 13 of the metal base material 10. In the second coating step, the second exposed portion 30B exposed from the edge portion 21B of the second coating film portion 20B to the end surface of the metal base material 10 is provided on at least a part of the peripheral portion 16 of the second surface 14 of the metal base material 10, and the second coating film portion 20B and the second exposed portion 30B are formed such that the second exposed portion 30B is disposed directly behind the first exposed portion 30A. In the first coating step and the second coating step, the first paint and the second paint are applied such that the first length L1 of the first exposed portion 30A from the end surface 15 of the metal base material 10 to the edge portion 21A of the first coating film portion 20A is equal to or greater than the second length L2 of the second exposed portion 30B from the end surface 15 of the metal base material 10 to the edge portion 21B of the second coating film portion 20B.

[0045] In the pre-coated metal sheet 1 according to the present embodiment, the first exposed portion 30A and the second exposed portion 30B are provided. Therefore, by joining at the peripheral portion 16 of the metal base material 10 provided with the first exposed portion 30A and the second exposed portion 30B, the operation of removing the first coating film portion 20A and the second coating film portion 20B before joining the metal base materials 10 becomes unnecessary. Thus, as shown in FIG. 6 and the like, the productivity of the joined body 100 in which the peripheral portions 16 of the metal base materials 10 are joined can be enhanced.

[0046] In the pre-coated metal plate 1 according to this embodiment, a first coating portion 20A is provided on the first surface 13 of the metal substrate 10, and a second coating portion 20B is provided on the second surface 14 of the metal substrate 10. Therefore, both the first surface 13 and the second surface 14 of the metal substrate 10 can be protected. For example, when the pre-coated metal plate 1 is used as a container for a battery, both the inner and outer surfaces of the container can be protected. For example, on the inner surface of the container, the insulation against contact with electrodes can be improved, and the corrosion resistance against contact with the electrolyte can be improved. On the outer surface of the container, the insulation against contact with electronic components and batteries placed adjacent to the container can be improved. Furthermore, on the outer surface of the container, the protective performance against external factors such as moisture, humidity, salt, acid, base, and corrosive substances can be improved.

[0047] Furthermore, when welding such as laser welding is performed at a joint, energy for joining is usually supplied from one side of the metal substrate 10, which is the workpiece. At the joint, the heat input due to the energy supply acts over a wide area on the first surface 13 (for example, the energy supply surface such as the laser irradiation surface) to which energy such as a laser is supplied. In contrast, on the second surface 14 (for example, the non-energy supply surface such as the non-laser irradiation surface) opposite to the side to which energy is supplied, the heat input tends to act over a relatively narrow area. For this reason, the welded area, including the molten part and the heat-affected zone (HAZ), tends to have a wider area (width) on the first surface 13 to which energy is supplied, while it tends to have a narrower width on the second surface 14 opposite to the first surface 13 to which energy is supplied.

[0048] In this embodiment, the first length L1 of the first exposed portion 30A on the first surface 13 of the pre-coated metal sheet 1 is equal to or greater than the second length L2 of the second exposed portion 30B on the second surface 14. When supplying energy for welding from the first surface 13 side, the first exposed portion 30A is widened in accordance with the weld portion that will be formed in a wide range on the first surface 13. And the first coating portion 20A is provided at a position away from the end surface 15 of the metal base material 10 which is the irradiation position. Therefore, when supplying energy for welding from the first surface 13 side, the influence on the first coating portion 20A located around the joint portion can be reduced. Further, on the second surface, the second exposed portion 30B is narrowed in accordance with the weld portion that will be formed in a narrow range, and the second coating portion 20B is provided up to a position close to the end surface 15 of the metal base material 10 which is the irradiation position. Therefore, the range in which the metal base material 10 is protected by the second coating portion 20B is widened. An additional coating process for forming an additional coating portion may be performed after the joining process described later. When the range in which the metal base material 10 is protected by the first coating portion 20A or the second coating portion 20B is widened, the range for providing the additional coating portion can be narrowed, so that the work of the additional coating process can be reduced.

[0049] Therefore, according to the pre-coated metal sheet 1 according to this embodiment, it is possible to protect both surfaces of the metal base material 10, and the productivity of the joined body 100 obtained by joining the pre-coated metal sheets 1 can be improved.

[0050] [3. Joint] Next, the joint 100 according to this embodiment will be described. The joint 100 comprises at least one pre-coated metal plate 1. The joint 100 is formed by joining at least one pre-coated metal plate 1. The end faces 15 of the peripheral edge 16 on which the exposed portion 30 of the metal substrate 10 is provided are joined to the pre-coated metal plate 1. The at least one pre-coated metal plate 1 may be one pre-coated metal plate 1, or at least two pre-coated metal plates 1. The at least two pre-coated metal plates 1 may be two, three, four, five, six, or ten pre-coated metal plates 1. When joining the end faces 15 of at least two metal substrates 10, the metal types of the metal substrates 10 may be the same or different. The welded joint may be at least one selected from the group consisting of, for example, butt joints, lap joints, and corner joints.

[0051] The joint 100 may be a cylindrical body 101, as shown in Figures 6, 7, 10, 11, 14, and 15.

[0052] For example, as shown in Figures 4, 5, 6, and 7, in the jointed body 100a, the pre-coated metal plate 1a may be joined by a butt joint at the end faces 15a, 15a of the peripheral edge portion 16a where the exposed portions 30Aa, 30Ba of the metal substrate 10a are provided, thereby forming a cylindrical body 101a. In such a jointed body 100, since the joint forming the peripheral wall of the jointed body 100 is at only one location, the risk of leakage can be reduced, for example, when the jointed body 100 is used as a container. Furthermore, since such a jointed body 100 can be formed by bending a single pre-coated metal plate 1a and then continuously joining them, it offers excellent productivity. In the embodiments shown in Figures 6 and 7, the end faces 15a of the first pair of sides 11a, including the first short side 11Aa and the second short side 11Ba, are joined together. However, the end faces 15 of the second pair of sides 12, including the first long side 12A and the second long side 12B, may be joined together.

[0053] Furthermore, when the end faces 15a, 15a of the peripheral edges 16a, 16a of the metal substrate 10a are said to abut each other, it means that the peripheral edges 16a, 16a of the metal substrate 10a that are adjacent to or in contact with each other are aligned at an angle of 135° to 180°. The angle at which the peripheral edges 16a, 16a of the metal substrate 10a abut each other may be 150° to 180°, 165° to 180°, or 180°. For example, as shown in Figure 4, when the peripheral edges 16a, 16a of the metal substrate 10a abut each other in a straight line, the angle at which the peripheral edges 16a, 16a of the metal substrate 10a abut each other is 180°. The metal substrates 10a to be butted together may be arranged by butting the end faces 15a, 15a of one metal substrate 10a together, as explained with reference to Figures 4 to 7, or by butting the end faces of two metal substrates 10b, 10c together, as explained with reference to Figures 8 to 11 and Figures 12 to 15.

[0054] As shown in Figures 8, 9, 10, and 11, in the joint 100, the pre-coated metal plates 1b may be joined by a corner joint with the end faces 15b, 15b of the peripheral portions 16b, where the exposed portions 30Ab, 30Bb of a pair of metal substrates 10b are provided, facing each other. In this configuration, various joints 100 can be formed by combining the pre-coated metal plates 1b. Also, in Figures 10 and 11, the end faces 15b, 15b of the peripheral portions 16b, 16b of two pre-coated metal plates 1b face each other to form a cylindrical body 101b, but the end faces 15 of the peripheral portion 16 of a single pre-coated metal plate 1 may also be joined by a corner joint with each other facing each other to form a cylindrical body 101.

[0055] Furthermore, when the end faces 15b, 15b of the peripheral edges 16b, 16b of the metal substrate 10b are said to be facing each other, it means that the peripheral edges 16b, 16b of the metal substrate 10b that are adjacent to or in contact with each other are aligned at an angle greater than 30° and less than 135°. The angle at which the peripheral edges 16b, 16b of the metal substrate 10b are aligned may be 60° or more and 120° or less, 75° or more and 105° or less, or 90°. For example, as shown in Figure 8, when the peripheral edges 16b, 16b of the metal substrate 10b are aligned at a right angle, the angle at which the peripheral edges 16b, 16b of the metal substrate 10b are aligned is 90°. The metal substrates to be butted together may be arranged with the end faces 15a, 15a of one metal substrate 10 facing each other, as explained with reference to Figures 4 to 7, or with the end faces of two metal substrates 10b, 10c facing each other, as explained with reference to Figures 8 to 11 and Figures 12 to 15.

[0056] As shown in Figures 12, 13, 14, and 15, in the joined body 100c, the pre-coated metal plate 1c may be joined by a corner joint to the side surface 17c (corresponding to the second surface 14 in this embodiment) of the peripheral edge 16c where the exposed portions 30Ac1, 30Bc1 of the metal base material 10c are provided, with the end face 15c of the peripheral edge 16c where the exposed portions 30Ac2, 30Bc2 of the metal base material 10c are provided butt together. Even in this configuration, various joined bodies 100 can be formed by combining the pre-coated metal plates 1c. In Figures 14 and 15, the end face 15c of one peripheral edge 16c of two pre-coated metal plates 1c, 1c is brought into contact with the side surface 17c of the other peripheral edge 16c to form a cylindrical body 101c. However, the end face 15 of the peripheral edge 16 of a single pre-coated metal plate 1 may be brought into contact with the side surface 17 of the peripheral edge 16 and joined by a corner joint to form a cylindrical body 101.

[0057] Furthermore, when it is said that the end face 15c of the peripheral edge 16c of the metal substrate 10c abuts against the side surface 17c of the peripheral edge 16c, it means that the peripheral edges 16c, 16c of the metal substrate 10c that are adjacent to or in contact with each other, are aligned at an angle greater than 5° and less than 175°. The angle at which the end face 15c of the peripheral edge 16c of the metal substrate 10c abuts against the side surface 17c of the peripheral edge 16c may be 30° or more and 150° or less, 30° or more and 120° or less, or 90°. For example, as shown in Figure 12, when the end face 15c of the peripheral edge 16c of the metal substrate 10c abuts against the side surface 17c of the peripheral edge 16c, the angle at which the end face 15c of the peripheral edge 16c of the metal substrate 10c abuts against the side surface 17c of the peripheral edge 16c is 90°. The metal substrates 10c to be butted together may have their end faces abutted against the side surface of one metal substrate 10, as explained with reference to Figures 4 to 7, or they may have the end face of one metal substrate 10 abutted against the side surface of the other, as explained with reference to Figures 8 to 11 and Figures 12 to 15.

[0058] In the joined body 100c, a first exposed portion 30Ac is formed on the first surface 13c of the metal substrate 10c, and a second exposed portion 30Bc is formed on the second surface 14c of the metal substrate 10c. The metal substrate 10c has a first pair of sides 11c. The first pair of sides 11c includes opposing first short sides 11Ac and second short sides 11Bc. Of the first exposed portion 30Ac, the first length L11 of the first exposed portion 30Ac1 formed on the first short side 11Ac is longer than the first length L12 of the first exposed portion 30Ac2 formed on the second short side 11Bc. Of the second exposed portion 30Bc, the second length L21 of the second exposed portion 30Bc1 formed on the first short side 11Ac is longer than the second length L22 of the second exposed portion 30Bc2 formed on the second short side 11Bc. On the first short side 11Ac, the first length L11 of the first exposed portion 30Ac1 formed on the first surface 13c is equal to the second length L21 of the second exposed portion 30Bc1 formed on the second surface 14c. On the first short side 11Ac, the first length L12 of the first exposed portion 30Ac2 formed on the first surface 13c is longer than the second length L22 of the second exposed portion 30Bc2 formed on the second surface 14c. The end face 15c of the peripheral edge 16c of the metal substrate 10c abuts against the second exposed portion 30Bc1 of the side surface 17c of the peripheral edge 16c of the metal substrate 10c. In this way, when energy for welding is supplied from the first surface 13c side, the first exposed portion 30Ac2 is widened to match the molten portion 110c that will be formed over a wide area on the first surface 13c. Furthermore, a second exposed portion 30Bc1 is provided on the side surface 17c on the second surface 14c side, in accordance with the molten portion 110c that will be formed.

[0059] As shown in Figures 12 and 13, in the pre-coated metal sheet 1c, the first length L11 of the first exposed portion 30Ac1 and the first length L12 of the first exposed portion 30Ac2 formed on the opposing first short side 11Ac and second short side 11Bc may be different (they may be asymmetrical). Also, in the pre-coated metal sheet 1c, the second length L21 of the second exposed portion 30Bc1 and the second length L22 of the second exposed portion 30Bc2 formed on the opposing first short side 11Ac and second short side 11Bc may be different.

[0060] Furthermore, as shown in Figures 10 and 11 and Figures 14 and 15, at least one pre-coated metal plate 1 may comprise at least two pre-coated metal plates 1. In the joint 100, the peripheral edges 16, 16 of at least two pre-coated metal plates 1, where the exposed portion 30 of the metal base material 10 is provided, may be joined together to form a cylindrical body 101. For example, at least two pre-coated metal plates 1, 1 may be joined by butt joints, with the end faces 15, 15 of the peripheral edges 16, 16, where the exposed portion 30 of the metal base material 10 is provided, facing each other. Also, as shown in Figures 10 and 11, in the joint 100b, at least two pre-coated metal plates 1b, 1b may be joined by facing each other, with the end faces 15b, 15b of the peripheral edges 16b, where the second exposed portion 30B of the metal base material 10b is provided, forming a corner joint. Furthermore, as shown in Figures 14 and 15, in the joined body 100c, at least two pre-coated metal plates 1c, 1c may be joined by a corner joint, with the end faces 15c of the peripheral edge 16c where the exposed portion 30c of the metal substrate 10c is provided abutting against the side surface 17c (corresponding to the second surface 14 in this embodiment) of the peripheral edge 16c where the exposed portion 30c of the metal substrate 10c is provided.

[0061] An additional coating portion, including an additional resin coating, may be provided in the region including the joint where the end faces 15 are joined. By providing the additional coating portion, the region including the joint can be protected, and properties such as insulation and corrosion resistance can be improved. The additional resin coating may extend from the joint, across the exposed portion 30, to the edge portion 21 of the coating portion 20.

[0062] As shown in Figure 18, the assembly 100d may be a container 102. The container 102 may be a battery container. The battery may be a prismatic battery or a cylindrical battery. The battery may be a primary battery or a secondary battery. The battery may be a lithium-ion secondary battery and a rechargeable battery such as a nickel-metal hydride battery. The battery may include a power generation element housed in the container 102. The power generation element may include a positive electrode, a negative electrode, and a separator placed between the positive electrode and the negative electrode.

[0063] In the pre-coated metal sheet 1, a first exposed portion 30 is provided on the periphery of a pair of opposing first sides 11, and a first exposed portion 30Ad may be provided on the periphery of at least one of a pair of opposing second sides 12 formed by connecting the ends of the first pair of sides 11. The jointed body 100d may comprise a cylindrical body 101d and a plate material 130. The periphery of the pair of first sides 11 may be joined to the cylindrical body 101d. The plate material 130 may be joined to the periphery 16d of at least one of the second pair of sides 12d on which the first exposed portion 30Ad is provided, thereby closing the opening 120 at at least one end of the cylindrical body 101d. Such a jointed body 100d can be used as a container 102. In addition, exposed portions 30 may be provided on the periphery of both sides of a pair of opposing second sides 12 formed by connecting the ends of the first pair of sides 11. In this case, plate material 130 may be joined to the periphery of both sides to close the openings 120 at both ends.

[0064] In the above-described embodiment, the joint 100 was explained as an example in which a rectangular plate material 130 is joined to a rectangular cylindrical body 101. The shape of the cylindrical body 101 is not limited to this, and may be a rectangular cylindrical shape having any number of corners, such as a triangular cylindrical shape, a pentagonal cylindrical shape, a hexagonal cylindrical shape, etc., or it may be cylindrical, elliptical cylindrical, semi-cylindrical, or partially cylindrical, or it may be a cylindrical shape that combines these shapes. For example, it may be a cylindrical shape having straight edges and curved corners sandwiched between the edges.

[0065] [4. Method for Manufacturing the Joined Body] Next, a method for manufacturing the joined body 100 according to this embodiment will be described. In the method for manufacturing the joined body 100 according to this embodiment, at least one pre-coated metal plate 1 is joined. The method for manufacturing the joined body 100 may include a processing step, a joining step, and an additional painting step.

[0066] (Processing step) In the processing step, the pre-coated metal sheet 1 is processed by forming. The forming step may include bending. Bending is a process of bending the pre-coated metal sheet 1. The bending step may include at least one selected from the group consisting of feed bending, die bending, and folding.

[0067] Feed bending is a process in which a pre-coated metal sheet 1 is sequentially bent while being fed. Feed bending may include at least one of roll bending and roll forming. Roll bending is a process in which the bending is performed using three rolls. Roll forming is a method of forming a pre-coated metal sheet 1 by passing it through a roll forming machine in which a plurality of roll dies having different shapes are arranged. Die bending is a process in which the pre-coated metal sheet 1 is pressed with a press machine. Die bending may include at least one selected from the group consisting of V-bend, U-bend, L-bend, R-bend, and O-bend. Folding is a process in which the pre-coated metal sheet 1 is bent with a folding machine. Folding is, for example, a process in which the pre-coated metal sheet 1 is folded by fixing a part of the pre-coated metal sheet 1 and curving one end of the pre-coated metal sheet 1 along a die. In the processing steps, from the viewpoint of productivity, it is preferable to bend the pre-coated metal sheet 1 by roll forming.

[0068] In the processing step, the peripheral edges 16, 16 on which the exposed portion 30 of the metal base material 10 is provided may be processed to be closer together. For example, in the processing step, the end faces 15 of the peripheral edges 16 on which the exposed portion 30 of the metal base material 10 is provided may be abutted against each other. Such processing makes it easier to form a butt joint. Alternatively, in the processing step, the end faces 15 of the peripheral edges 16 on which the exposed portion 30 of the metal base material 10 is provided may be facing each other. Alternatively, in the processing step, the end faces 15 of the peripheral edges 16 on which the exposed portion 30 of the metal base material 10 is provided may be abutted against the side surface 17 of the peripheral edges 16 on which the exposed portion 30 of the metal base material 10 is provided. Such processing makes it easier to form a corner joint.

[0069] In the processing step, the end faces 15 of the peripheral edges 16 on a single pre-coated metal sheet 1, where the exposed portion 30 of the metal base material 10 is provided, may be brought closer together. For example, a single pre-coated metal sheet 1 may be processed into a cylindrical shape so that the end faces 15 are brought closer together.

[0070] Specifically, the pre-coated metal sheet 1 may be rectangular in shape. Exposed portions 30 may be provided on the peripheral edges 16 of a pair of opposing first sides 11 of the rectangular pre-coated metal sheet 1, and exposed portions 30 may also be provided on the peripheral edge 16 of at least one of a pair of opposing second sides 12 formed by connecting the ends of the first pair of sides 11. Furthermore, in the processing step, the pre-coated metal sheet 1 may be processed to bring the peripheral edges 16 of the first pair of sides 11 closer together.

[0071] (Joining Process) In the joining process, the edges of the metal substrates 10 are joined together. In the joining process, the end faces of the peripheral edges 16 on which the exposed portion 30 of the metal substrate 10 is provided may be joined. For example, in the joining process, the end faces 15 that were brought close together in the processing process may be joined. Specifically, in the joining process, the end faces 15 that were butted together in the processing process may be joined together to form a butt joint. In the joining process, the end faces 15 that were facing each other in the processing process may be joined together to form a corner joint. In the joining process, the side surfaces 17 (for example, the second surface 14) and the end faces 15 that were butted together in the processing process may be joined together to form a corner joint. In the joining process, the peripheral edges 16 on which the exposed portion 30 of the metal substrate 10 that has not been processed in the processing process is provided may be joined together, or the end faces 15 of the peripheral edges 16 may be joined together. Before joining, degreasing treatment with a solvent or the like may be performed as needed.

[0072] In the joining process, the peripheral edges 16 on which the exposed portion 30 of the metal base material 10 of one pre-coated metal sheet 1 is provided may be joined together. Alternatively, in the joining process, the peripheral edges 16 on which the exposed portion 30 of the metal base material 10 of at least two pre-coated metal sheets 1 is provided may be joined together. Alternatively, in the joining process, the peripheral edges 16 on which the exposed portion 30 of the metal base material 10 of at least two pre-coated metal sheets 1 processed in the processing process are provided may be joined together.

[0073] In the joining process, the pre-coated metal sheet 1 manufactured in the painting process may be joined. This makes it possible to join a pre-coated metal sheet 1 comprising a metal substrate 10 and a coated portion 20, with an exposed portion 30 provided on at least one surface of the metal substrate 10.

[0074] The welded joint formed by welding the metal base material 10 may be a butt joint, an lap joint, or a square joint. A butt joint is a joint formed by butt welding in which the metal base materials 10 placed on the same plane face each other at an angle of 135 to 180 degrees. An lap joint is a joint in which the metal base materials 10 are placed parallel to each other at an angle of 0 to 5 degrees and overlap each other. A square joint is a joint in which the end faces 15 of two metal base materials 10 are joined at an angle of 30 to 135 degrees. Lap joints and square joints may include fillet joints. A fillet joint is a joint formed by fillet welding in which two orthogonal surfaces are welded together, and has a triangular cross-section.

[0075] In the joining process, the metal substrates 10 can be joined by applying energy to the joining portion of the metal substrates 10. In the joining process, a welding heat source including at least one selected from the group consisting of a laser, arc, frictional heat, Joule heat, flame, and electron beam may be supplied to the metal substrates 10. The joining of the metal substrates 10 may include at least one of pressure welding and fusion welding. Pressure welding is a type of welding in which an external force is applied to cause plastic deformation of the joining surface. Fusion welding is a type of welding performed without applying external force while the joining surface is molten. The welding may include at least one selected from the group consisting of laser welding, resistance welding, arc welding, ultrasonic welding, and friction stir welding.

[0076] Laser welding is a welding method that uses laser light as an energy source, and is also called laser beam welding or laser light welding. In laser welding, welding can be performed by irradiating the joint on the first surface 13 of the metal substrate 10 with laser light.

[0077] Resistance welding is a welding method that uses electrical energy as an energy source. It is performed by heating the joint with resistance heat generated by passing an electric current, and then applying pressure to the joint. Resistance welding can weld a metal substrate 10 by supplying a high-frequency current of 10 kHz or higher to the joint of the metal substrate 10 and generating Joule heat.

[0078] Arc welding is a type of welding that uses an electric arc as an energy source. Arc welding may include gas-shielded arc welding. Gas-shielded arc welding may include at least one of TIG (Tungsten Inert Gas) welding and MIG (Metal Inert Gas) welding. TIG welding is a type of welding that uses a non-consumable tungsten electrode and shields the electrode and the weld with an inert gas containing argon, helium, or a mixture thereof. MIG welding is a type of welding that uses a consumable electrode and shields the electrode and the weld with an inert gas containing argon, helium, or a mixture thereof.

[0079] Ultrasonic welding converts vibrational energy from ultrasonic waves into frictional heat at the joint, and the metal substrate 10 can be welded by the frictional heat generated at the joint. Friction stir welding, for example, can weld the metal substrate 10 using frictional heat generated by a rotating tool.

[0080] (Additional coating process) In the additional coating process, a coating paint for joints is applied to the area including the joint formed in the joining process to form an additional coating portion including an additional resin film. By providing the additional coating portion, the area including the joint can be protected, and properties such as insulation and corrosion resistance can be improved. The coating paint for joints may be the same as the first coating paint and the second coating paint described above, or they may be different.

[0081] As shown in Figures 6-7, 10-11, and 14-15, the joined body 100 may be a cylindrical body 101. Furthermore, as shown in Figures 4-5, 8-9, and 12-13, in the joining process, the peripheral edges 16 of the first pair of sides 11 that were brought close together in the processing process may be joined to form a cylindrical body 101 having an opening 120.

[0082] Furthermore, as shown in Figure 18, the joined body 100 may also be a container 102. Then, as shown in Figures 16 to 19, a container 102 may be formed by joining the peripheral edge 16 of at least one of the second pair of sides 12 of the cylindrical body 101, which has an exposed portion 30, to a plate material 130 and closing the opening 120.

[0083] More specifically, in this manufacturing method, the joined body 100 may be formed, for example, by bending a rectangular pre-coated metal plate 1 in the processing step to create a cylindrical shape such as a square tube, and then butting the end faces 15a of the metal base material 10 together, as shown in Figures 4 and 5. Then, as shown in Figures 6 and 7, in the joining step, the end faces 15a of the first pair of sides 11a that were brought close together in the processing step are joined by butt welding. In this way, the pre-coated metal plate 1 can be joined via the molten portion 110a through the processing step and the joining step, and a cylindrical body 101a with a square tube shape having an opening 120 can be formed.

[0084] Furthermore, the joint 100 may be formed by bending the two pre-coated metal plates 1 into an L-shape, for example, as shown in Figures 8 and 9. Then, as shown in Figures 10 and 11, in the joining process, the end faces 15b of the metal base material 10 of the two pre-coated metal plates 1 may be brought close together to form a corner joint and joined. Even with this method, the pre-coated metal plates 1 can be joined via the molten portion 110b, and a rectangular cylindrical body 101b can be formed.

[0085] Furthermore, the joint 100 may be formed by bending the two pre-coated metal plates 1 into an L-shape, for example, as shown in Figures 12 and 13. Then, as shown in Figures 14 and 15, in the joining process, the side surfaces 17c (second surface 14) and end surfaces 15c of the metal base material 10 of the two pre-coated metal plates 1 may be brought close together to form a corner joint. Even with this method, the pre-coated metal plates 1 can be joined via the molten portion 110c, and a rectangular cylindrical body 101c can be formed.

[0086] In any of the methods shown in Figures 4 to 7, Figures 8 to 11, and Figures 12 to 15, the first coating portion 20A is positioned on the outside of the cylindrical body 101, and the second coating portion 20B is positioned on the inside of the cylindrical body 101. Therefore, when supplying energy for joining from the first surface 13 side, the impact on the first coating portion 20A located around the joining point can be reduced. In addition, the area over which the metal substrate 10 is protected by the second coating portion 20B can be widened.

[0087] Next, the manufacturing method of the container 102 according to this embodiment will be described in detail with reference to Figures 16 to 19. The container 102 can be manufactured by joining a plate material 130 to the cylindrical body 101d made as described above. Specifically, as shown in Figures 16 and 17, the opening 120 of the cylindrical body 101d is covered with the plate material 130, and the end face 15d of the metal base material 10 in the cylindrical body 101d and the end face 131 of the plate material 130 are brought close together to form a corner joint. Then, as shown in Figures 18 and 19, the end face 15d of the metal base material 10 in the cylindrical body 101d and the end face 131 of the plate material 130 are joined. In this way, the cylindrical body 101d and the plate material 130 can be joined by joining via the molten portion 110d, and the container 102 can be formed. Alternatively, the end face 15d of the metal base material 10 in the cylindrical body 101d and the side surface 132 of the plate material 130 may be joined.

[0088] As described above, the jointed body 100 according to this embodiment is a jointed body 100 in which at least one pre-coated metal plate 1 is joined. The at least one pre-coated metal plate 1 comprises a plate-shaped metal substrate 10 and a coating portion 20 including a resin coating, provided on at least one surface of the metal substrate 10. An exposed portion 30 is provided on at least a part of the peripheral edge 16 on at least one surface of the metal substrate 10, where the metal substrate 10 is exposed from the edge 21 of the coating portion 20 to the end face 15 of the metal substrate 10. The end face 15 of the peripheral edge 16 on which the exposed portion 30 of the metal substrate 10 is provided may be joined.

[0089] Furthermore, the method for manufacturing the joined body 100 according to this embodiment is a method for manufacturing a joined body 100 in which at least one pre-coated metal plate 1 is joined. The at least one pre-coated metal plate 1 comprises a plate-shaped metal substrate 10 and a coating portion 20 including a resin coating, provided on at least one surface of the metal substrate 10. An exposed portion 30 is provided on at least a part of the peripheral edge 16 on at least one surface of the metal substrate 10, where the metal substrate 10 is exposed from the edge 21 of the coating portion 20 to the end face 15 of the metal substrate 10. The end face 15 of the peripheral edge 16 on which the exposed portion 30 of the metal substrate 10 is provided may be joined. The method for manufacturing the joined body 100 may include a joining step of joining the end face 15 of the peripheral edge 16 on which the exposed portion 30 of the metal substrate 10 is provided.

[0090] <Effects> In the joined body 100 according to this embodiment, since the joining is performed at the exposed portion 30 of the pre-coated metal plate 1, the work of removing the resin coating before the painting process is eliminated. Therefore, the productivity of the joined body 100 can be increased.

[0091] When joining overlapping sections of pre-coated metal plates 1, in order to avoid affecting the resin coating around the joining area, it is necessary to provide exposed areas on at least the surface to which energy is supplied (e.g., the energy supply surface such as the laser irradiation surface) and the surface that is in contact with the overlapping sections. If the molten section penetrates the metal substrate, it is also necessary to provide exposed areas on the surface opposite to the energy supply surface (e.g., the non-energy supply surface such as the non-laser irradiation surface). When joining overlapping sections, it is necessary to align the positions of the exposed areas formed on each of the overlapping metal substrates when overlapping the workpieces. Since it is difficult to accurately match the overlapping position and the width (or amount) of the overlap, it is necessary to provide exposed areas with a margin in an area that extends from the irradiation position of the overlapping section.

[0092] In the jointed body 100 according to this embodiment, an exposed portion 30 is provided on the peripheral edge 16 of the metal substrate 10, and the end face 15 on which the exposed portion 30 of the peripheral edge 16 is provided is joined by a butt joint or a corner joint. In this case, the joining location is positioned by butting or facing the end faces 15, and the range of the molten portion and heat-affected zone formed by energy supply such as a laser is also naturally determined. Therefore, it is sufficient to provide an exposed portion 30 on the peripheral edge 16 to which the end face 15 is joined, and it is not necessary to provide a wide exposed portion 30 as in the case of overlapping. For this reason, the width of the exposed portion 30 on the peripheral edge 16 of the metal substrate 10 can be made relatively narrow, and the range of the coated film portion 20 can be widened.

[0093] Typically, the end face 15 of the metal substrate 10 has irregularities on its surface due to the cutting process. Therefore, even if the end face 15 is painted, it is difficult to apply a uniform coating due to the surface irregularities, and a portion of the end face 15 of the metal substrate 10 may remain exposed.

[0094] Conventionally, lap joints were formed by welding so that the molten portion penetrated the overlapping portion. However, in cases where fillet welding is not performed, the end face remains on the surface after joining. In this case, due to the non-uniformity of the coating on the end face, a portion of the metal substrate may be exposed, potentially leading to problems such as reduced insulation and corrosion resistance.

[0095] In the joined body 100 according to this embodiment, an exposed portion 30 is provided on the peripheral edge 16 of the metal substrate 10, and the end faces 15 on the peripheral edge 16 of the metal substrate 10, on which the exposed portion 30 is provided, are joined by butting or facing each other. Therefore, it is possible to suppress the end faces 15 remaining exposed on the surface after joining. This reduces problems caused by the influence of the non-uniformity of the coating portion 20 of the end face 15.

[0096] The entire contents of Japanese Patent Application No. 2024-188980 (Filing Date: October 28, 2024) are incorporated herein by reference.

[0097] Although this embodiment has been described above with reference to examples and comparative examples, this embodiment is not limited to these, and various modifications are possible within the scope of the gist of this embodiment.

[0098] 1 Pre-coated metal sheet 10 Metal base material 11 First pair of sides 12 Second pair of sides 13 First surface 14 Second surface 15 End surface 16 Peripheral edge 20 Coating portion 20A First coating portion 20B Second coating portion 21A Edge 21B Edge 30 Exposed portion 30A First exposed portion 30B Second exposed portion 100 Joint 101 Cylindrical body 102 Container 130 Plate material L1 First length L2 Second length

Claims

1. A pre-coated metal sheet comprising: a plate-shaped metal substrate; a first coating portion including a first resin coating provided on a first surface which is one side of the metal substrate; and a second coating portion including a second resin coating provided on a second surface which is the side of the metal substrate opposite to the first surface, wherein a first exposed portion is provided on at least a part of the peripheral edge of the first surface of the metal substrate, from the edge of the first coating portion to the end face of the metal substrate; a second exposed portion is provided on at least a part of the peripheral edge of the second surface of the metal substrate, from the edge of the second coating portion to the end face of the metal substrate; the second exposed portion is located directly behind the first exposed portion; and the first length of the first exposed portion from the end face of the metal substrate to the edge of the first coating portion is equal to or greater than the second length of the second exposed portion from the end face of the metal substrate to the edge of the second coating portion located directly behind the first exposed portion.

2. The pre-coated metal sheet according to claim 1, wherein the first length is greater than the second length.

3. The pre-coated metal sheet according to claim 1 or 2, wherein the first length and the second length are 1 mm or more and 10 mm or less.

4. The pre-coated metal sheet according to any one of claims 1 to 3, wherein the second length is 0.5 times or more and 1 time or less than the first length.

5. The pre-coated metal sheet according to any one of claims 1 to 4, wherein the thickness of the metal substrate is 0.1 mm or more and 10 mm or less.

6. The pre-coated metal sheet according to any one of claims 1 to 5, wherein the thickness of the first resin coating and the second resin coating is 5 μm or more and 1000 μm or less.

7. The pre-coated metal plate according to any one of claims 1 to 6, wherein the first resin coating and the second resin coating are insulating, and the pre-coated metal plate is a pre-coated metal plate for a battery container.

8. A method for manufacturing a pre-coated metal sheet comprising: a plate-shaped metal substrate; a first coating portion provided on a first surface which is one side of the metal substrate and includes a first resin coating; and a second coating portion provided on a second surface which is the side of the metal substrate opposite to the first surface and includes a second resin coating, wherein the method for manufacturing the pre-coated metal sheet comprises: a first coating step of applying a first paint to the first surface of the metal substrate to form the first coating portion including the first resin coating, and forming a first exposed portion on the peripheral edge of the metal substrate in contact with the first coating portion; and a second coating step of applying a second paint to the second surface of the metal substrate to form the second coating portion including the second resin coating, and forming a second exposed portion on the peripheral edge of the metal substrate in contact with the second coating portion. A method for manufacturing a pre-coated metal sheet, comprising: forming the first coating portion and the first exposed portion in the first coating portion in the first coating step such that a first exposed portion, exposed from the edge of the first coating portion to the end face of the metal substrate, is provided on at least a part of the peripheral edge of the first surface of the metal substrate; forming the second coating portion and the second exposed portion in the second coating step such that a second exposed portion, exposed from the edge of the second coating portion to the end face of the metal substrate, is provided on at least a part of the peripheral edge of the second surface of the metal substrate, and the second exposed portion is positioned directly behind the first exposed portion; and applying the first paint and the second paint in the first and second coating steps such that the first length of the first exposed portion from the end face of the metal substrate to the edge of the first coating portion is equal to or greater than the second length of the second exposed portion from the end face of the metal substrate to the edge of the second coating portion.

9. The method for manufacturing a pre-coated metal sheet according to claim 8, wherein the first length is greater than the second length.

10. The method for manufacturing a pre-coated metal sheet according to claim 8 or 9, wherein the first length and the second length are 1 mm or more and 10 mm or less.

11. The method for manufacturing a pre-coated metal sheet according to any one of claims 8 to 10, wherein the second length is 0.5 times or more and 1 time or less than the first length.

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