Sealed can body, battery cell case, and method for manufacturing the sealed can body

Abstract

Provided are: a sealing can body (1) including a lid (10), a body (20), and a welding metal (30) that joins the lid (10) and the body (20), the sealing can body (1) being characterized in that the lid (10) is made of a stainless steel material and the body (20) is made of a plated steel material having a Ni-based plating layer on the surface of a base steel material, or the lid (10) is made of a plated steel material having a Ni-based plating layer on the surface of a base steel material and the body (20) is made of a stainless steel material, and in that [Cr] + 4 × [Ni] ≧ 5.0 is satisfied when [Cr] denotes the average amount of Cr in the welding metal (30) and [Ni] denotes the average amount of Ni in the welding metal (30); and a method for manufacturing said sealing can body.

Description

Technical Field

[0001] The present disclosure relates to a sealed can body, a battery cell case, and a method for manufacturing a sealed can body. The present disclosure claims priority based on Japanese Patent Application No. 2023-203653 filed in Japan on December 1, 2023, and incorporates the content herein by reference.

Background Art

[0002] Many of the batteries used in electric vehicles are lithium-ion batteries. As battery cell cases for housing lithium-ion battery cells, there are shapes such as cylindrical, rectangular, and pouch-shaped. Among these, rectangular lithium-ion battery cell cases are often made of aluminum as described in Patent Document 1. Patent Document 1 discloses a secondary battery aluminum can body assembled by laser welding a lid body and an exterior body made of an aluminum alloy plate, and a method for manufacturing the same.

[0003] In addition, as battery cell cases for lithium-ion batteries, there are cases made of stainless steel cases or plated steel sheets. For example, Patent Document 2 discloses a sealed container for a rectangular battery in which a lid plate made of a metal plate is inserted into a rectangular opening formed at one end of a metal case, and the fitting portions are sequentially laser welded. As the material of this case, a nickel-plated steel sheet is used.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention Invention

[0005] The rectangular battery cell cases described above are often assembled by laser welding the top cover and the body. However, the laser-welded areas are covered with less nickel plating, and the corrosion resistance improvement effect from the plating is less pronounced compared to the base material that makes up the top cover and body. Therefore, under extremely harsh conditions, there is a possibility that the inner surface of the welded area may corrode. Furthermore, it is difficult to apply corrosion-resistant treatment to the inner surface of the welded area after the top cover and body of the battery cell case have been laser-welded.

[0006] This disclosure has been made in view of the above, and aims to provide a sealed can body having a highly corrosion-resistant laser-welded part, a method for manufacturing the same, and a battery cell case using this sealed can body. [Means for solving the problem]

[0007] (1) A sealing container according to one aspect of the present disclosure is A sealed can body comprising a lid, a body, and a weld metal joining the lid and the body, The aforementioned lid is made of stainless steel, The fuselage is made of plated steel having a Ni-based plating layer on the surface of the base steel material. When the average Cr content of the weld metal is [Cr] and the average Ni content of the weld metal is [Ni], the following conditions are met: [Cr] + 4 × [Ni] ≥ 5.0. It is characterized by the following: (2) In the sealed can body described in (1) above, there may be no welded parts in the body. (3) A sealing can according to one aspect of the present disclosure is A sealed can body comprising a lid, a body, and a weld metal joining the lid and the body, The aforementioned cover is made of plated steel having a Ni-based plating layer on the surface of the base steel material. The aforementioned fuselage is made of stainless steel. When the average Cr content of the weld metal is [Cr] and the average Ni content of the weld metal is [Ni], the following conditions are met: [Cr] + 4 × [Ni] ≥ 5.0. It is characterized by the following: (4) In the sealed can body described in (3) above, welded parts may be present in the body. (5) In the sealed can body described in any one of (1) to (4) above, the carbon content of the base steel material may be greater than 0 and less than or equal to 0.07% by mass. (6) In the sealed can described in any one of the above items (1) to (5), the thickness of the stainless steel material may be 0.1 to 1.4 mm, and the thickness of the plated steel material may be 0.1 to 1.4 mm. (7) In the sealed can described in any one of items (1) to (6) above, the thickness of the Ni-based plating layer may be 0.3 to 10 μm. (8) In the sealed can body described in any one of the above items (1) to (7), an Fe-Ni alloy layer may be provided between the Ni-based plating layer and the base steel material. (9) The sealed can body described in any one of the above items (1) to (8) further includes a bottom cover provided opposite to the lid, and at least one of the lid and the bottom cover may be made of plated steel having a Ni-based plating layer on the surface of the base steel material. (10) A battery cell case according to one aspect of the present disclosure uses a sealing can described in any one of paragraphs (1) to (9) above. (11) A method for manufacturing a sealed can according to one aspect of the present disclosure is: A method for manufacturing a sealed can body, comprising a lid, a body, and a weld metal for joining the lid and the body, A process of forming the lid by processing stainless steel material, A process of forming the fuselage by processing a plated steel material having a Ni-based plating layer on the surface of a base steel material, A step of joining the lid and the body by welding, Includes, When the average Cr content of the weld metal is [Cr] and the average Ni content of the weld metal is [Ni], the following conditions must be met: [Cr] + 4 × [Ni] ≥ 5.0. It is characterized by the following: (12) In the method for manufacturing a sealed can described in (11) above, The processing of the fuselage may be deep drawing. (13) The manufacturing method of a sealed can body according to one aspect of the present disclosure is a manufacturing method of a sealed can body including a lid body, a body, and a welding metal for joining the lid body and the body, including a step of processing a stainless steel material to form the lid body, a step of processing a non-plated steel material to form the body, a step of providing a Ni-based plating layer on the surface of the body, a step of joining the lid body and the body by welding, and when the average Cr amount of the welding metal is [Cr] and the average Ni amount of the welding metal is [Ni], satisfying [Cr] + 4 × [Ni] ≧ 5.0, characterized by this. (14) The manufacturing method of a sealed can body according to one aspect of the present disclosure is a manufacturing method of a sealed can body including a lid body, a body, and a welding metal for joining the lid body and the body, including a step of processing a stainless steel material to form the body, a step of processing a plated steel material having a Ni-based plating layer on the surface of the base steel material to form the lid body, a step of joining the lid body and the body by welding, and when the average Cr amount of the welding metal is [Cr] and the average Ni amount of the welding metal is [Ni], satisfying [Cr] + 4 × [Ni] ≧ 5.0, characterized by this. (15) In the manufacturing method of the sealed can body described in (14) above, the processing of the body may be welding.

Effect of the Invention

[0008] The laser welded portion of the sealed can body according to the present disclosure and the battery cell case using the sealed can body according to the present disclosure has high corrosion resistance. Further, according to the manufacturing method of the sealed can body according to the present disclosure, a sealed can body having a laser welded portion with high corrosion resistance can be provided.

Brief Description of the Drawings

[0009] [Figure 1] It is a schematic perspective view for explaining a sealed can body according to an embodiment of the present disclosure. [Figure 2] It is a schematic perspective view for explaining a modified example of a sealed can body according to an embodiment of the present disclosure. [Figure 3] It is a view for explaining an example of a lid body and a body in the vicinity of a welded part of a sealed can body according to an embodiment of the present disclosure, and is a schematic cross-sectional view of the sealed can body in a plane perpendicular to the welding line. [Figure 4] It is a view for explaining another example of a lid body and a body in the vicinity of a welded part of a sealed can body according to an embodiment of the present disclosure, and is a schematic cross-sectional view of the sealed can body in a plane perpendicular to the welding line. [Figure 5] It is a view for explaining another example of a lid body and a body in the vicinity of a welded part of a sealed can body according to an embodiment of the present disclosure, and is a schematic cross-sectional view of the sealed can body in a plane perpendicular to the welding line. [Figure 6] It is a view for explaining another example of a lid body and a body in the vicinity of a welded part of a sealed can body according to an embodiment of the present disclosure, and is a schematic cross-sectional view of the sealed can body in a plane perpendicular to the welding line. [Figure 7] It is a schematic perspective view for explaining a modified example of a sealed can body according to an embodiment of the present disclosure. [Figure 8] It is a view for explaining another example of a lid body and a body in the vicinity of a welded part of a sealed can body according to an embodiment of the present disclosure, and is a schematic cross-sectional view of the sealed can body in a plane perpendicular to the welding line. [Figure 9] It is a view for explaining another example of a lid body and a body in the vicinity of a welded part of a sealed can body according to an embodiment of the present disclosure, and is a schematic cross-sectional view of the sealed can body in a plane perpendicular to the welding line.

Mode for Carrying Out the Invention

[0010] The embodiments of this disclosure will be described below with examples, but it is obvious that this disclosure is not limited to the examples described below. In the following description, specific numerical values ​​and materials may be given as examples, but other numerical values ​​and materials may be applied as long as the effects of the invention relating to this disclosure are obtained. In addition, each component of the embodiments described below can be combined with one another. Furthermore, in this specification, numerical ranges represented using "~" mean a range that includes the numbers written before and after "~" as the lower and upper limits, respectively. In this specification, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes, as long as their intended purpose is achieved.

[0011] In the following embodiments, "steel material" includes steel plates, parts obtained by machining steel plates into shapes other than flat plates, and steel plates formed by joining different types of steel plates. "Stainless steel material" includes stainless steel plates and parts obtained by machining stainless steel plates into shapes other than flat plates.

[0012] [Sealed container] Figure 1 shows a sealed container 1 according to this embodiment. The sealed container 1 of this embodiment includes a lid 10, a body 20, and a weld metal 30 that joins the lid 10 and the body 20. A sealed container is defined as a container with a sealed structure that prevents the contents, such as liquid, from leaking out of the container. In this embodiment, the sealed container 1 has a structure in which the lid 10 and the body 20 are joined by weld metal 30, so that the contents inside the sealed container 1 do not leak out. To achieve this structure, a weld is formed around the entire circumference of the connection between the lid 10 and the body 20. The weld is the part that includes the weld metal 30.

[0013] [Lid] The lid 10 is joined to the body 20 to form the sealed can body 1. As will be described later, the material constituting the lid 10 is stainless steel or plated steel having a Ni-based plating layer on the surface of the base steel. In the example in Figure 1, the surface of the lid 10 is parallel to the X and Y coordinate axes.

[0014] The lid 10 may be made of, for example, a single steel plate, or it may be made of multiple steel plates, stainless steel plates, etc., stacked together. Alternatively, these metal plates may be joined together by welding or the like. The lid 10 may be provided with an injection port for injecting electrolyte after sealing the sealed container 1, holes for passing electrodes, notches, protrusions, recesses, etc.

[0015] In the example shown in Figure 1, the lid 10 is connected to the opening 21 of the body 20, which will be described later, and is positioned to face the bottom surface 20e. As will be described later, the outer circumference of the lid 10 may be provided with a raised portion 11 and an edge portion 12, or an edge portion 12.

[0016] [body] The fuselage 20, as illustrated in Figure 1, is composed of opposing sides 20a and 20b, opposing sides 20c and 20d, and a bottom surface 20e. Each of the sides 20a, 20b, 20c, and 20d is connected at one end to each end of the bottom surface 20e and is configured to rise from the bottom surface 20e. The surfaces of each of the sides 20a, 20b, 20c, and 20d intersect with the surface of the bottom surface 20e. In the example in Figure 1, the bottom surface 20e is parallel to the X and Y coordinate axes, and the sides 20a, 20b, 20c, and 20d are parallel to the Z coordinate axis.

[0017] One end of side 20a, which extends in a direction intersecting the base surface 20e, is connected to the end of side 20c, and the other end is connected to the end of side 20d. One end of side 20b, which extends in a direction intersecting the base surface 20e, is connected to the end of side 20c, and the other end is connected to the end of side 20d. In the example in Figure 1, sides 20a and 20b are parallel to the Y and Z coordinate axes, and sides 20c and 20d are parallel to the X and Z coordinate axes. Also, in the example in Figure 1, each end connecting sides 20a, 20b, 20c, and 20d to each other is parallel to the Z coordinate axis.

[0018] The body 20 has an opening 21 to which the lid 10 is joined. The opening 21 is formed by the ends of each of the sides 20a, 20b, 20c, and 20d that are connected to the bottom surface 20e and the ends that are opposite to them. As described above, since the sealed container 1 is sealed, it is preferable that the outer shape of the lid 10 and the inner or outer shape of the opening 21 of the body 20 are the same shape. The inner shape of the opening 21 of the body 20 means the shape corresponding to the inner surface shape of the body 20. Also, the outer shape of the opening 21 of the body 20 means the shape corresponding to the outer surface shape of the body 20.

[0019] [Bottom lid] Figure 2 shows a schematic perspective view illustrating a modified example of the sealing can body 1 according to this embodiment. As illustrated in Figure 2, the body 20 may not have a bottom surface 20e, and a member similar to the lid 10 may be used as the bottom cover 40.

[0020] The material constituting the bottom cover 40 may be the same as that of the cover 10, or it may be different from that of the cover 10. Preferably, the bottom cover 40 and the body 20 are joined with a weld metal having substantially the same composition as the weld metal 30 that joins the cover 10 and the body 20. Furthermore, the shape of the bottom cover 40 may be the same as that of the lid 10. In the example shown in Figure 2, the bottom cover 40 is connected to an opening 22 located on the opposite side of the opening 21 of the body 20, and the lid 10 and the bottom cover 40 are positioned so that their surfaces face each other. The outer circumference of the bottom cover 40 may be provided with a raised portion and an edge, or an edge, and these portions may be joined to the body 20.

[0021] Note that the X, Y, and Z axes in Figures 1 and 2 are all orthogonal to each other.

[0022] [Stainless steel material] The chemical composition of stainless steel is as follows: Cr (chromium): greater than 10.00% and less than or equal to 30.00% by mass. C (carbon): 0~0.100% by mass, Si (silicon): 0-1.20% by mass, Mn (manganese): 0-5.00 mass%, P (phosphorus): 0~0.050% by mass, S (sulfur): 0~0.0500% by mass, Ni (nickel): 0-25.00% by mass, Mo (Molybdenum): 0-4.00% by mass, Cu (copper): 0~3.00% by mass, Ti (Titanium): 0-0.800 mass%, Al (aluminum): 0-0.30% by mass, Co (cobalt): 0-1.00 mass%, Nb (niobium): 0-0.800 mass%, N (nitrogen): 0~0.3000% by mass, Sn (tin): 0~0.500% by mass, It contains, It is preferable that the remainder contains Fe (iron) and impurities. Impurities refer to components contained in the raw materials or components that are introduced during the manufacturing process and are not intentionally included. For example, trace amounts of components other than Fe, such as W, Mg, and B, may be present as impurities. Stainless steel materials having such a chemical composition are preferable because they have excellent corrosion resistance (particularly corrosion resistance to the electrolyte of the contents (electrolyte resistance)).

[0023] The chemical composition of stainless steel materials is measured using ICP (Inductively Coupled Plasma) emission spectroscopy. However, carbon (C), sulfur (S), and nitrogen (N) are measured using well-known gas analysis methods.

[0024] A thickness of 0.1 to 1.4 mm for the stainless steel material is more preferable. This has the advantage of providing a battery cell case that is lightweight and has excellent mechanical strength. The thickness of the stainless steel material is determined by measuring the thickness at five points using a micrometer and taking the arithmetic mean of these measurements.

[0025] [Plated steel materials] Plated steel is a type of steel that has a nickel-based plating layer on its surface. The chemical composition of the base steel material is as follows: C (carbon): more than 0 and 0.090% by mass or less, Si (silicon): greater than 0 and less than 0.800% by mass, Mn (manganese): greater than 0 and less than or equal to 1.00 mass%, P (phosphorus): more than 0 and 0.05% by mass or less, S (sulfur): more than 0 and 0.050% by mass or less, Mo (Molybdenum): 0-0.300 mass%, Cu (copper): 0~0.30% by mass, Ti (Titanium): 0-0.100 mass%, Al (aluminum): 0-0.10% by mass, Co (cobalt): 0-0.1% by mass, Nb (niobium): 0-0.100 mass%, N (nitrogen): 0~0.0300% by mass, Sn (tin): 0~0.03% by mass, Cr (chromium): 0-0.20 mass%, Ni (nickel): 0-0.2% by mass, B (Boron): 0-0.0030% by mass It contains, It is preferable that the remainder contains Fe (iron) and impurities. Impurities refer to components contained in the raw materials or components that are introduced during the manufacturing process and are not intentionally included. For example, trace amounts of components other than Fe, such as W, Mg, and V, may be present as impurities. Steel sheets with such a chemical composition are preferable because they have excellent formability.

[0026] The chemical composition of the base steel material for plated steel materials is measured using ICP (Inductively Coupled Plasma) emission spectrometry in accordance with JIS G 1258-1:2014. However, carbon (C), sulfur (S), and nitrogen (N) are measured by well-known gas analysis methods.

[0027] The carbon content of the base steel material (substrate) is more preferably greater than 0 and less than or equal to 0.07% by mass. This has the advantage of further improving formability. If metal ions dissolve into the electrolyte, it can negatively affect battery performance. Therefore, corrosion resistance (electrolyte resistance) is required for the materials used in battery cell cases. In terms of corrosion resistance, nickel-plated steel and stainless steel are suitable. On the other hand, in the case of plating that exhibits corrosion resistance, especially against natural environments, through a sacrificial corrosion protection mechanism, such as zinc-plated steel, a large amount of ions can dissolve from the plating into the electrolyte, making it unsuitable as a material for battery cell cases. For example, zinc-plated steel, which is cheaper than nickel-plated steel and does not require electrolyte resistance, is used as a material for general structural materials such as building materials.

[0028] A nickel-based plating layer is provided on the surface of the base steel material that constitutes plated steel. A nickel-based plating layer is a plating layer whose main component is nickel. Specifically, the nickel-based plating layer is defined as the range in which the nickel concentration is 80% by mass or higher when measured using GDS (Glow Discharge Optical Emission Spectrometry).

[0029] A thickness of 0.3 to 10.0 μm is more preferable for the Ni-based plating layer. Increasing the thickness of the Ni-based plating layer improves electrolyte resistance, but also increases costs. A thickness of 0.3 to 10.0 μm for the Ni-based plating layer offers the advantage of a good balance between electrolyte resistance and cost. The thickness of the Ni-based plating layer can be measured using a GDS device. Using the GDS device, the thickness of any five points on the plating layer is measured, and the arithmetic mean of these measurements is taken as the thickness of the Ni-based plating layer.

[0030] An Fe-Ni alloy layer may be present between the Ni-based plating layer and the base steel material. The Fe-Ni alloy layer is a layer with a Ni concentration of 10 to less than 80% by mass. The presence of the Fe-Ni alloy layer improves corrosion resistance and formability. The Fe-Ni alloy layer can be measured using a GDS (Gross Deposition Spectroscopy) device.

[0031] From the viewpoint of improving workability, the thickness of the Fe-Ni alloy layer is preferably 0.2 μm or more, and more preferably 0.5 μm or more. The thickness of the Fe-Ni alloy layer can be measured using a GDS device. The thickness is measured at five points using the GDS device, and the arithmetic mean of these measurements is taken as the thickness of the Fe-Ni alloy layer.

[0032] A Ni-W plating layer may be further provided on top of the Ni-based plating layer. Having a Ni-W plating layer on the surface improves corrosion resistance and formability. The Ni-W plating layer is defined as the range where the W concentration is 10% by mass or higher when measured using GDS. The thickness of the Ni-W plating layer can be measured using a GDS device. The thickness is measured at five points using the GDS device, and the arithmetic mean of these measurements is taken as the thickness of the Ni-W plating layer.

[0033] A thickness of 0.1 to 1.4 mm for the plated steel is more preferable. This has the advantage of providing a battery cell case that is lightweight and has excellent mechanical strength. The thickness of the plated steel is determined by measuring the thickness at five points using a micrometer, and taking the arithmetic mean of these measurements as the thickness of the plated steel.

[0034] In the sealed can body 1 of this embodiment, the lid 10 is made of stainless steel, and the body 20 is made of plated steel having a Ni-based plating layer on the surface of the base steel material. With this configuration, the amount of alloying elements in the weld metal can be increased, improving the corrosion resistance of the weld metal. By using stainless steel for one of the lid 10 and the body 20 and plated steel for the other, it is not necessary to use expensive stainless steel as the sole material for the sealing can body 1. Furthermore, because plated steel has good formability, using plated steel for the fuselage 20 can reduce manufacturing costs.

[0035] Furthermore, as illustrated in Figure 2, if the body 20 does not have a bottom surface 20e and uses a member similar to the lid 10 as the bottom cover 40, the body 20 (sides 20a, 20b, 20c, and 20d) may be made of plated steel, and the lid 10 and bottom cover 40 may be made of stainless steel.

[0036] When the fuselage 20 is made of plated steel, it is preferable that there are no welds on the fuselage 20. For example, the fuselage 20 can be formed without welds by deep drawing or the like. Because there are no welds, it has excellent corrosion resistance without the need for special treatment.

[0037] Alternatively, in the sealed can body 1 of this embodiment, the lid 10 is made of plated steel having a Ni-based plating layer on the surface of the base steel material, and the body 20 is made of stainless steel. With this configuration, the amount of alloying elements in the weld metal can be increased, improving the corrosion resistance of the weld metal. By using stainless steel for one of the lid 10 and the body 20 and plated steel for the other, it is not necessary to use expensive stainless steel as the sole material for the sealing can body 1.

[0038] Furthermore, as illustrated in Figure 2, if the bottom surface 20e is not provided in the body 20 and a member similar to the lid 10 is used as the bottom cover 40, the body 20 (sides 20a, 20b, 20c, and 20d) may be made of stainless steel, and plated steel may be used for the lid 10 and bottom cover 40. Alternatively, the body 20 may be made of stainless steel, and only one of the lid 10 or bottom cover 40 may be made of plated steel while the other is made of stainless steel.

[0039] When the fuselage 20 is made of stainless steel, it is preferable that the fuselage 20 has welded joints. For example, the fuselage 20 can be formed by welding or other processes to create a fuselage 20 with welded joints. Compared to plated steel, stainless steel has lower formability, so welding has the advantage of making it easier to process into a predetermined shape.

[0040] [Weld metal] In the sealed can body 1 of this embodiment, when the average amount of Cr in the weld metal is [Cr] and the average amount of Ni is [Ni], the [Cr] + 4 × [Ni] (corrosion resistance index) is 5.0 or higher. The average Cr content of the weld metal 30 is measured using ICP (Inductively Coupled Plasma) emission spectroscopy. The Cr content at five points in the weld metal is measured, and the arithmetic mean of these values ​​is taken as the average Cr content. The average Ni content in the weld metal is calculated using the same method as the average Cr content.

[0041] Weld metal 30 is the part of the weld where steel materials, etc., melt and solidify due to irradiation with a laser beam during laser welding. It is a part of the weld and is metal that melted and solidified during welding. When filler is used during laser welding, the material source for the weld metal 30 is the multiple steel materials being joined and the filler. When steel is plated, the plating components also melt and become part of the weld metal. In addition to elements from these sources, the weld metal may also contain oxygen and nitrogen from the air, as well as unavoidable impurities. As described above, by making one of the lid 10 and body 20 from stainless steel and the other from plated steel, the amount of alloying elements in the weld metal can be increased, thereby improving the corrosion resistance of the weld metal.

[0042] In the sealed can body 1 illustrated in Figure 1, the weld metal 30 extends along the X and Y coordinate axes and is formed around the outer circumference of the lid 10 and the entire circumference of the opening 21 of the body 20.

[0043] For example, the thickness of the plated steel material that makes up the lid or body may be reduced to adjust the components that dissolve into the weld metal. Pressing is a good method for adjusting the thickness so as not to affect the plating layer.

[0044] (Joint shape 1) The following describes an example of the joint shape at the connection point between the lid 10 and the body 20. Figure 3 is a diagram illustrating an example of the lid 10 and body 20 near the weld of the sealing can body according to this embodiment. Figure 3 is a schematic cross-sectional view of the sealing can body 1 in a plane perpendicular to the direction of extension of the weld line of the weld metal 30. In the example shown in Figure 3, the lid 10 includes a raised portion 11 and an edge portion 12. The raised portion 11 and the edge portion 12 are provided along the outer circumference of the lid 10. By having such a raised portion 11 and edge portion 12, the edge portion 12 of the lid 10 engages with the opening 21 of the body 20, and the lid 10 can be supported.

[0045] As illustrated in Figure 3, the weld metal 30 is provided at the end of the body 20 on the opening 21 side and at least along the edge 12. The weld metal 30 may also extend up to the rising portion 11.

[0046] (Joint shape 2) Figure 4 illustrates another example of the lid 10 and body 20 near the weld of the sealing can body according to this embodiment. Figure 4 is a schematic cross-sectional view of the sealing can body 1 in a plane perpendicular to the direction of extension of the weld line of the weld metal 30. In the example shown in Figure 4, the lid 10 is provided with a raised portion 11. The raised portion 11 is provided along the outer circumference of the lid 10. Having such a raised portion has the advantage that the cut end surface, where the plating protection of the plated steel is weak, is not exposed to the inner surface.

[0047] As illustrated in Figure 4, the weld metal 30 is provided at the end of the body 20 on the opening 21 side and its vicinity, and across the rising portion 11.

[0048] (Joint shape 3) Figure 5 illustrates another example of the lid 10 and body 20 near the weld of the sealing can body according to this embodiment. Figure 5 is a schematic cross-sectional view of the sealing can body 1 in a plane perpendicular to the direction of extension of the weld line of the weld metal 30. In the example shown in Figure 5, the lid 10 is made of stainless steel, and the body 20 is made of plated steel with a Ni-based plating layer on the surface of the base steel. Although the cut end surface of the lid 10 is exposed to the inner side, the lid 10 has high corrosion resistance because it is made of stainless steel. Since there is no need to provide a raised portion 11 or edge portion 12 on the lid 10 or body 20, there is an advantage in that manufacturing costs can be reduced.

[0049] As illustrated in Figure 5, the weld metal 30 is provided along the end of the body 20 on the opening 21 side and its vicinity, and across the cut end surface of the lid 10.

[0050] (Joint shape 4) Figure 6 illustrates another example of the lid 10 and body 20 near the weld of the sealing can body according to this embodiment. Figure 6 is a schematic cross-sectional view of the sealing can body 1 in a plane perpendicular to the direction of extension of the weld line of the weld metal 30. In the example shown in Figure 6, the lid 10 is made of plated steel with a Ni-based plating layer on the surface of the base steel material, and the body 20 is made of stainless steel. The cut end surface of the body 20 is exposed on the inner side, but since the body 20 is made of stainless steel, it has high corrosion resistance. There is an advantage in that it is not necessary to provide a raised portion 11 or edge portion 12 on the lid 10 or body 20, so manufacturing costs can be reduced.

[0051] As illustrated in Figure 6, the weld metal 30 is provided along the end of the body 20 on the opening 21 side and its vicinity, and across the cut end surface of the lid 10.

[0052] For example, when using the sealing can body 1 of this embodiment as a battery cell case for housing lithium-ion battery cells in an electric vehicle, as illustrated in Figures 3 to 6, the joint shape of the body 20 is such that it does not protrude toward the outer surface of the body 20, which has the advantage of allowing the cell cases to be arranged without gaps and preventing interference with other parts.

[0053] In the sealed container 1 according to this embodiment, the length L of the body 20 in the direction perpendicular to the lid 10 may be longer than the length W of the lid 10 in the longitudinal direction. For example, although not particularly limited, the length L of the body 20 in the direction perpendicular to the lid 10 may be 1.5 times or more the length W of the lid 10 in the longitudinal direction. This has the advantage that even in a space with limited height, the lid 10 equipped with terminals can be positioned laterally to increase the battery's space utilization. For example, by using a battery with terminals arranged on a laterally positioned lid 10 as the battery for an electric vehicle, the thickness of the electric vehicle's floor can be reduced, and the passenger space of the electric vehicle can be expanded.

[0054] Figure 7 illustrates a sealed container 1 in which the length L of the body 20 in the direction perpendicular to the lid 10 is longer than the length W of the lid 10 in the longitudinal direction. The direction perpendicular to the lid 10 means the direction perpendicular to the plate surface of the lid 10. In the example in Figure 7, the length L of the body 20 in the direction perpendicular to the lid 10 is the length in the direction parallel to the Z coordinate axis of the body 20. The length W of the lid 10 in the longitudinal direction means the maximum length of the lid 10 in the direction parallel to the plate surface of the lid 10. In the example in Figure 7, the length W of the lid 10 in the longitudinal direction is the length in the direction parallel to the X coordinate axis of the lid 10.

[0055] In the sealed can body 1 shown in Figure 7, a bottom cover 40 is provided facing the lid 10, similar to the example in Figure 2. Also, in the sealed can body 1 shown in Figure 7, a welded portion (weld metal 31) exists on the body 20. Such a sealed can body 1 is not particularly limited, but can be manufactured, for example, by the manufacturing method described later (manufacturing method of sealed can body 3B).

[0056] The method for manufacturing a sealed can body according to this embodiment is described below. This manufacturing method allows for the suitability of producing a sealed can body equipped with a highly corrosion-resistant laser-welded section. However, it is obvious that a sealed can body obtained by a method other than the manufacturing method described below will be considered to be the above-described sealed can body as long as it satisfies the requirements of this application.

[0057] [Method for manufacturing sealed cans 1A] The method for manufacturing a sealed can body according to this embodiment is: The process of forming a lid by processing stainless steel material, A process of forming a fuselage by processing plated steel material having a Ni-based plating layer on the surface of a base steel material, The process of joining the lid and the body by welding, Includes.

[0058] (Lid formation process) The lid 10 is formed by processing stainless steel material into a predetermined shape. As described in the above embodiment, the outer circumference of the lid 10 may be provided with a rising portion 11 and an edge portion 12, or an edge portion 12.

[0059] (Body formation process) The fuselage 20 is formed by processing plated steel material having a Ni-based plating layer on the surface of a base steel material. Processing methods include deep drawing and welding. Deep drawing, for example, involves press forming a single plated steel sheet to form a body 20 having sides 20a, 20b, 20c, 20d and a bottom surface 20e, as described in the above embodiment. When steel is processed by deep drawing, the fuselage 20 is made of a single piece of steel (e.g., a steel plate), so there are no welds on the sides 20a, 20b, 20c, 20d and the bottom 20e.

[0060] The welding process involves preparing plated steel sheets to form the sides 20a, 20b, 20c, 20d, and bottom 20e, and welding them together to form the fuselage 20. Alternatively, the sides 20a, 20b, 20c, 20d, and bottom 20e may be formed by bending a single steel sheet, and the ends of these sheets may be joined together to form the fuselage 20. When steel materials are processed by welding, the fuselage 20 has at least one weld. In this case, the weld metal of the weld on the fuselage 20 shall be made using filler wire, and when the average amount of Cr in the weld metal is [Cr] and the average amount of Ni is [Ni], the [Cr] + 4 × [Ni] (corrosion resistance index) shall be 5.0 or higher.

[0061] When processing plated steel material to form the fuselage 20, it is preferable to process the fuselage 20 by deep drawing. Since there are no welded parts in the fuselage 20 formed by deep drawing, it has excellent corrosion resistance without the need for special treatment (for example, post-weld plating, coating treatment, or painting).

[0062] (Joining process) In the joining process, the lid 10 and the body 20 are joined by laser welding. During laser welding, as long as proper welding is performed, the laser beam can be irradiated from any of the directions indicated by arrows A to F in the diagram.

[0063] Figure 8 shows an example in which, in the joint shape shown in Figure 3, the weld metal 30 is provided over the end of the body 20 on the opening 21 side and at least the edge 12. In this case, the laser beam may be irradiated from, for example, the direction of arrow A or B in Figure 8.

[0064] Figure 9 shows the joint shape shown in Figure 4, in which the weld metal 30 is provided near the end of the body 20 on the opening 21 side and near the end of the rising portion 11. In this case, the laser beam may be irradiated from, for example, the direction of arrow D or E in Figure 9.

[0065] [Method for manufacturing a sealed container 1B] When manufacturing a sealed can body 1, which consists of a lid 10, a body 20, and a bottom lid 40, as illustrated in Figure 2, the process for forming the body 20 differs from the above-described method for manufacturing a sealed can body 1A.

[0066] For example, a body 20 having an opening 21 may be formed from plated steel material by deep drawing as described above, and the bottom surface may be cut off to form an opening 22. Alternatively, a single steel plate may be bent in the same direction to form sides 20a, 20b, 20c, and 20d. In this case, the ends of the bent steel plate may be joined by riveting or welding. Alternatively, a body 20 having sides 20a, 20b, 20c, and 20d may be formed by joining multiple steel plates.

[0067] The bottom cover 40 may be manufactured using the same process as the cover body 10. In the joining process, the joining of the bottom cover 40 to the body 20 may be carried out under the same conditions as the joining of the cover body 10 to the body 20.

[0068] [Method for manufacturing sealed cans 2A] The method for manufacturing a sealed can body according to this embodiment is: The process of forming a lid by processing stainless steel material, The process of processing unplated steel material to form the fuselage, A process of applying a Ni-based plating layer to the surface of the fuselage, The process of joining the lid and the body by welding, Includes.

[0069] (Lid formation process) The lid 10 is formed by processing stainless steel material into a predetermined shape. As described in the above embodiment, the outer circumference of the lid 10 may be provided with a rising portion 11 and an edge portion 12, or an edge portion 12.

[0070] (Body formation process) The fuselage 20 is formed by processing unplated steel. Processing methods include deep drawing and welding. Deep drawing, for example, involves press forming a single unplated steel sheet to form a body 20 having sides 20a, 20b, 20c, 20d and a bottom surface 20e, as described in the above embodiment. When steel is processed by deep drawing, the fuselage 20 is made of a single piece of steel (e.g., a steel plate), so there are no welds on the sides 20a, 20b, 20c, 20d and the bottom 20e.

[0071] The welding process involves preparing unplated steel materials for the sides 20a, 20b, 20c, 20d, and bottom 20e, and welding them together to form the fuselage 20. Alternatively, the sides 20a, 20b, 20c, 20d, and bottom 20e may be formed by bending a single steel plate, and the ends of these plates may be joined together to form the fuselage 20. Furthermore, since a Ni-based plating layer is applied to cover the welded area after welding, the weld metal contained in the weld between unplated steel materials does not need to meet the compositional requirements of the weld metal 30 described above.

[0072] (Process for applying a nickel-based plating layer) After forming the body 20, a nickel-based plating layer is applied to the surface of the body 20. There are no restrictions on the method of applying the nickel-based plating layer to the surface of the body 20, but for example, a nickel-based plating layer can be applied to the surface of the body 20 by electroplating it using a nickel plating bath (Watts bath containing 250 g / L nickel sulfate, 50 g / L nickel chloride, and 30 g / L boric acid (pH=3.0)). Note that the surface of the body 20 refers to both the inner and outer surfaces of the body 20.

[0073] (Joining process) In the joining process, the lid 10 and the body 20 are joined by laser welding. During laser welding, as long as proper welding is performed, the laser beam can be irradiated from any of the directions indicated by arrows A to F in the diagram.

[0074] [Method for manufacturing sealed cans 2B] When manufacturing a sealed can body 1, which consists of a lid 10, a body 20, and a bottom lid 40, as illustrated in Figure 2, the process for forming the body 20 differs from the above-described method for manufacturing a sealed can body 2A.

[0075] For example, a body 20 having an opening 21 may be formed from unplated steel material by deep drawing as described above, and the bottom surface may be cut off to form an opening 22. Alternatively, a single steel plate may be bent in the same direction to form sides 20a, 20b, 20c, and 20d. In this case, the ends of the bent steel plate may be joined by riveting or welding. Alternatively, a body 20 having sides 20a, 20b, 20c, and 20d may be formed by joining multiple steel plates.

[0076] The bottom cover 40 may be manufactured using the same process as the cover body 10. In the joining process, the joining of the bottom cover 40 to the body 20 may be carried out under the same conditions as the joining of the cover body 10 to the body 20.

[0077] [Method for manufacturing sealed cans 3A] The method for manufacturing a sealed can body according to this embodiment is: The process of processing stainless steel material to form the fuselage, A process of forming a lid by processing a plated steel material having a Ni-based plating layer on the surface of a base steel material, The process of joining the lid and the body by welding, Includes.

[0078] (Lid formation process) The cover 10 is formed by processing a plated steel material, which has a Ni-based plating layer on the surface of a base steel material, into a predetermined shape. As described in the above embodiment, the outer circumference of the lid 10 may be provided with a rising portion 11 and an edge portion 12, or an edge portion 12.

[0079] (Body formation process) The fuselage 20 is formed by processing stainless steel material. Processing methods include deep drawing and welding. Deep drawing, for example, involves press forming a single sheet of stainless steel to form a body 20 having sides 20a, 20b, 20c, 20d and a bottom surface 20e, as described in the above embodiment. When steel is processed by deep drawing, the fuselage 20 is made of a single piece of steel (e.g., a steel plate), so there are no welds on the sides 20a, 20b, 20c, 20d and the bottom 20e.

[0080] The welding process involves preparing stainless steel plates to form sides 20a, 20b, 20c, 20d, and bottom 20e, and welding them together to form the body 20. Alternatively, a single steel plate may be bent to form sides 20a, 20b, 20c, 20d, and bottom 20e, and these ends may be joined together to form the body 20. Note that the weld metal contained in the welded joint between stainless steel materials does not need to meet the composition requirements of the weld metal 30 because it has excellent corrosion resistance. Alternatively, a single steel plate may be bent into a cylindrical shape, and the ends of the steel plates may be joined together with weld metal 31 to produce a cylindrical intermediate material, and this cylindrical intermediate material may be expanded into a rectangular shape to form the body 20.

[0081] When processing stainless steel material to form the fuselage 20, welding is preferred for the processing of the fuselage 20. Compared to plated steel material, stainless steel material has low formability, so welding makes it easier to process into a predetermined shape.

[0082] (Joining process) In the joining process, the lid 10 and the body 20 are joined by laser welding. During laser welding, as long as proper welding is performed, the laser beam can be irradiated from any of the directions indicated by arrows A to F in the diagram.

[0083] [Method for manufacturing a sealed can body 3B] When manufacturing a sealed can body 1, which consists of a lid 10, a body 20, and a bottom lid 40, as illustrated in Figure 2, the process for forming the body 20 differs from the above-described method for manufacturing a sealed can body 3A.

[0084] For example, a body 20 having an opening 21 may be formed from stainless steel material by deep drawing as described above, and the bottom surface may be cut off to form an opening 22. Alternatively, a single steel plate may be bent in the same direction to form sides 20a, 20b, 20c, and 20d. In this case, the ends of the bent steel plate may be joined by riveting or welding. Alternatively, a body 20 having sides 20a, 20b, 20c, and 20d may be formed by joining multiple steel plates.

[0085] The bottom cover 40 may be manufactured using the same process as the cover body 10. In the joining process, the joining of the bottom cover 40 to the body 20 may be carried out under the same conditions as the joining of the cover body 10 to the body 20.

[0086] The sealed container according to the above-described embodiment can preferably be used as a battery case or a battery cell case. In particular, the sealed container according to the above-described embodiment can preferably be used as a prismatic lithium-ion battery cell case. A battery cell case is a case for housing battery cells. A battery cell is the smallest unit of a battery in a battery module. A battery module is constructed by electrically connecting a plurality of battery cells. A battery pack can also be constructed by further electrically connecting a plurality of battery modules. A battery pack can also be constructed by electrically connecting a large number of battery cells without constructing a battery module. Battery modules or battery packs are used, for example, as a power source for electric vehicles. However, the use of battery modules or battery packs in electric vehicles is not essential. It is also possible to mount a large number of battery cells in an electric vehicle without constructing a module or pack.

[0087] When the sealed container according to the embodiment is used as a battery cell case, the sealed container contains a positive electrode active material, a separator, a negative electrode active material, and an electrolyte. Furthermore, when the sealed can body according to the embodiment is used as a battery cell case, positive electrode leads, negative electrode leads, positive electrode terminals, negative electrode terminals, etc., may be provided. The positive electrode leads, negative electrode leads, positive electrode terminals, negative electrode terminals, etc., may be provided on the lid 10 and / or bottom lid 40 described above. Alternatively, the positive electrode leads, negative electrode leads, positive electrode terminals, negative electrode terminals, etc., may be provided on the body 20. When the sealed can body according to the embodiment is used as a battery cell case, the battery cell case body may be used as a negative electrode case with the negative electrode terminal. When the sealed can body according to the embodiment is used as a battery cell case, it may be used as a neutral case insulated from the positive electrode terminals and negative electrode terminals. In addition, holes for attaching safety valves, electrolyte injection ports, electrodes, etc., may be made in the lid 10, bottom lid 40, and body 20. In this case, by providing holes in the parts made of stainless steel, corrosion resistance of the holes can be ensured. [Examples]

[0088] The invention described herein will be explained in detail below with reference to examples, but the invention is not limited thereto.

[0089] (Example 1) In this example, a battery was created using a sealed can body, in which the lid and body were joined by laser welding, as the battery cell case, and its performance was evaluated.

[0090] In the following Example 1 or Example 2, the following steel sheets (base steel sheets) were prepared as the base material (substrate) for the plated steel sheets. For the body and lid, we prepared aluminum-killed steel with a thickness of 0.3 mm (manufactured by Nippon Steel Corporation), general cold-rolled steel sheet SPCC with a thickness of 0.2 to 0.3 mm (manufactured by Nippon Steel Corporation), and Nb-SULC steel with a thickness of 0.2 to 1.4 mm (manufactured by Nippon Steel Corporation).

[0091] The above-mentioned base steel sheets were subjected to either Ni-based plating or Ni-W-based plating to produce plated steel sheets for use as the material for the body and lid. The plating conditions for each type of plating are as follows. Separately, the main constituent components of the plating layer for the following two types of Ni-based plating were identified using the method described above, and it was confirmed that they were Ni.

[0092] [Ni-based plating] A nickel-based plating layer was formed on a steel sheet by electroplating using a plating bath containing the following components. After plating, heat treatment was performed under the conditions described below. Ni plating bath: Watts bath containing 250 g / L nickel sulfate, 50 g / L nickel chloride, and 30 g / L boric acid (pH=3.0) Plating bath temperature: 50℃ Current density: 20A / dm2 Heat treatment conditions: 750-800°C x 20 seconds

[0093] [Ni-W plating] Using the Ni plating bath described above and the Ni-W alloy plating bath described below, the base steel sheet was plated in the order of electroplating Ni followed by Ni-W alloy plating to form a Ni-W plating layer. After plating, heat treatment was performed under the conditions described below. Ni-W alloy plating bath: Sodium tungstate 65g / L, nickel sulfate 50g / L, diammonium hydrogen citrate 100g / L, sodium formate 13g / L Plating bath temperature: 50℃ Current density: 20A / dm2 Heat treatment conditions: 750-800°C x 20 seconds

[0094] In Example 1, the body of the sealed can was fabricated by deep drawing using the plated steel sheets shown in Table 1. In the formability evaluation described later, for sealed can bodies where cracks were observed after fabrication, the body was refabricated by press working and laser welding, and the elution test described later was performed. Filler P, shown in Table 3, was used during laser welding of the body. The filler was supplied at half the welding speed. The molded shape of the fuselage was set to a size equivalent to DIN standard PHEV2 (depth: 91 mm, width: 26.5 mm, height: 148 mm). Table 1 also shows the chemical composition of the base steel sheet for the plated steel sheet (the remainder includes Fe and impurities).

[0095] [Table 1]

[0096] S-Ni is a plating layer that has an Fe-Ni alloy layer between the Ni-based plating layer and the base steel material. Ni-W is a plating layer that has a Ni-W-based plating layer on top of the S-Ni layer.

[0097] Furthermore, lids for sealed cans were fabricated using the stainless steel plates shown in Table 2. The lid was molded to one of the joint shapes 1 to 3 and then joined to the body described above. The remainder of the chemical composition in Table 2 includes Fe and impurities.

[0098] [Table 2]

[0099] Using the lids and bodies described above, each sealed can was created in the combinations shown in Tables 4 and 5. The battery was placed inside the sealed container to create a battery cell case. The battery was manufactured as follows:

[0100] (Battery construction) • Positive plate Lithium cobalt oxide was used as the positive electrode active material. Acetylene black and polyvinylidene fluoride (PVDF) were mixed with this in a mass ratio of 10:10:1, and then coated onto aluminum foil as an aqueous dispersion and dried. This was rolled to a predetermined thickness and cut to a predetermined size to form the positive electrode plate. • Negative plate Amorphous carbon was used as the negative electrode active material. This was dry-mixed with acetylene black, a conductive material, and then N-methyl-2-pyrrolidone (NMP), which is polyvinylidene fluoride dissolved in it, was uniformly dispersed in the mixture to create a paste with a mass ratio of carbon:acetylene black:PVDF = 88:5:7. This paste was applied to a Cu foil, dried, rolled to a predetermined thickness, and then cut to a predetermined size to form the negative electrode plate. • Separator A polyethylene microporous membrane was used as the separator. ·Electrolyte The electrolyte used was a solution (1M-LiPF6 EC / DEC(1 / 1)) prepared by mixing ethylene carbonate and diethyl carbonate in a 1:1 volume ratio and adding 1 mol / L of lithium hexafluorophosphate.

[0101] The electrode group, wound with a separator in between the positive and negative electrode plates, was flattened to fit into the body of the battery cell case (sealed can). The positive electrode plate was welded to an Al lead, and the negative electrode plate to a Ni lead. The Al lead was welded to the positive terminal on the lid, and the Ni lead was welded to the negative terminal on the lid.

[0102] The lid was laser-welded to the body. In some experimental cases, the filler shown in Table 3 was used during laser welding. The remainder of the chemical composition in Table 3 includes Fe and impurities. The filler was supplied at half the welding speed.

[0103] [Table 3]

[0104] The inside of the battery was dried in an atmosphere with a dew point of -76°C to remove moisture. The electrolyte was then injected through the injection port in the same atmosphere. The battery was then charged to 3.6-4.2V in the same atmosphere. This procedure electrolyzed any remaining moisture inside the battery. After that, the injection port was closed with a stopper.

[0105] The laser welding of the lid and the body was adjusted to the following conditions to achieve a penetration depth approximately equal to the thickness of the lid plate. Continuous wave Output: 0.8~4.0kW Speed: 2.0~5.0m / min Focus shift: 0-10mm (Gathering diameter with JF: 0.6mm) Shielding gas: Ar

[0106] The following evaluations were performed on each of the obtained sealed containers. The results are shown in Tables 4 and 5.

[0107] (Composition of weld metal) The average Cr content and average Ni content of the weld metal were measured using the following method. Weld metal was cut from the case, and a sample of the weld metal was taken. Using an emission spectrometer (Shimadzu Corporation: ICPS-8100), the components of this sample were measured at five points, and the arithmetic mean was taken as the average Cr content or average Ni content.

[0108] When the average Cr content of the weld metal is [Cr] and the average Ni content is [Ni], [Cr] + 4 × [Ni] ... Equation 1 The value was used as the corrosion resistance index.

[0109] (Moldability) The body of each sealing container used before the battery cell case was created was observed. If the body could be formed from the steel plate without wrinkles or cracks, it was marked as ○ (Good), and if cracks were observed after the body was formed, it was marked as × (Bad).

[0110] (Leaching test) After sealing the injection port, the battery cell case was held at 80°C for 750 hours. After holding, a portion of the battery cell case was disassembled in an atmosphere with a dew point of -76°C, and the electrolyte was collected using a pipette or similar tool. The amount of metal leached from the electrolyte was analyzed using an ICP-MS (model: Agilent 7700x, manufactured by Agilent Technologies, Inc.). A Fe component of 50 ppm or less in the solution was rated as ◎ (Excellent), between 50 ppm and 75 ppm as ○ (Good), and above 75 ppm as × (Bad).

[0111] [Table 4]

[0112] [Table 5]

[0113] As can be seen from the results in Tables 4 and 5, in the examples that met the requirements of the present application, the amount of Fe component dissolved in the solution was trace, less than 75 ppm, and the moldability of the body was also good.

[0114] (Example 2) In this example, a battery was created using a sealed can body, in which the lid and body were joined by laser welding, as the battery cell case, and its performance was evaluated.

[0115] In Example 2, the body of the sealed can was fabricated by press working and welding using the stainless steel plates shown in Table 2. The molded shape of the body was equivalent to the DIN standard PHEV2 size (depth: 91 mm, width: 26.5 mm, height: 148 mm). Furthermore, lids for the sealed can bodies were fabricated using the plated steel sheets shown in Table 1. The lids were shaped to have one of the joint shapes 1, 2, or 4, and then joined to the body described above.

[0116] Using the lids and bodies described above, each sealed can was created in the combinations shown in Tables 6 and 7. A battery cell case was created by housing the battery inside the sealed container. The battery manufacturing conditions were the same as those for the battery in Example 1.

[0117] Each of the obtained sealed cans was evaluated for weld metal composition and elution in the same manner as in Example 1. The results are shown in Tables 6 and 7.

[0118] [Table 6]

[0119] [Table 7]

[0120] As can be seen from the results in Tables 6 and 7, in the examples that met the requirements of the present application, only trace amounts of Fe dissolved in the solution. [Industrial applicability]

[0121] The laser-welded portions of the sealed can body and battery cell cases using the sealed can body according to this disclosure have high corrosion resistance. Furthermore, the manufacturing method of the sealed can body according to this disclosure makes it possible to provide a sealed can body with a laser-welded portion that has high corrosion resistance. For this reason, the present invention is extremely useful in industry. [Explanation of Symbols]

[0122] 1. Enclosed container 10 Lid 20 Torso 30, 31 Weld metal 40 Bottom lid

Claims

1. A sealed can body comprising a lid, a body, and a weld metal joining the lid and the body, The aforementioned lid is made of stainless steel, The fuselage is made of plated steel having a Ni-based plating layer on the surface of the base steel material. When the average Cr content of the weld metal is [Cr] and the average Ni content of the weld metal is [Ni], the following conditions are met: [Cr] + 4 × [Ni] ≥ 5.0 A sealed container characterized by the following features.

2. The fuselage has no welded joints. The sealed can body according to feature 1.

3. A sealed can body comprising a lid, a body, and a weld metal joining the lid and the body, The aforementioned cover is made of plated steel having a Ni-based plating layer on the surface of the base steel material. The aforementioned fuselage is made of stainless steel. When the average Cr content of the weld metal is [Cr] and the average Ni content of the weld metal is [Ni], the following conditions are met: [Cr] + 4 × [Ni] ≥ 5.0 A sealed container characterized by the following features.

4. The fuselage has welded joints. The sealed can body according to feature 3.

5. The carbon content of the aforementioned base steel material is greater than 0 and less than or equal to 0.07% by mass. A sealed can body according to any one of claims 1 to 4.

6. The thickness of the aforementioned stainless steel material is 0.1 to 1.4 mm. The thickness of the plated steel material is 0.1 to 1.4 mm. A sealed can body according to any one of claims 1 to 4.

7. The thickness of the Ni-based plating layer is 0.3 to 10 μm. A sealed can body according to any one of claims 1 to 4.

8. A Fe-Ni alloy layer is provided between the Ni-based plating layer and the base steel material. A sealed can body according to any one of claims 1 to 4.

9. The present invention further includes a bottom cover provided opposite to the cover, wherein at least one of the cover and the bottom cover is made of plated steel having a Ni-based plating layer on the surface of the base steel material. The sealing can body according to any one of claims 3 or 4.

10. Using a sealed can body according to any one of claims 1 to 4, Battery cell case.

11. A method for manufacturing a sealed can body, comprising a lid, a body, and a weld metal for joining the lid and the body, A process of forming the lid by processing stainless steel material, A process of forming the fuselage by processing a plated steel material having a Ni-based plating layer on the surface of a base steel material, A step of joining the lid and the body by welding, Includes, When the average Cr content of the weld metal is [Cr] and the average Ni content of the weld metal is [Ni], the condition [Cr] + 4 × [Ni] ≥ 5.0 is satisfied. A method for manufacturing a sealed can body, characterized by the following:

12. The aforementioned processing of the fuselage is deep drawing. A method for manufacturing a sealed can body according to claim 11, characterized in that way.

13. A method for manufacturing a sealed can body, comprising a lid, a body, and a weld metal for joining the lid and the body, A process of forming the lid by processing stainless steel material, A process of forming the fuselage by processing unplated steel material, The process of providing a Ni-based plating layer on the surface of the fuselage, A step of joining the lid and the body by welding, Includes, When the average Cr content of the weld metal is [Cr] and the average Ni content of the weld metal is [Ni], the following conditions are met: [Cr] + 4 × [Ni] ≥ 5.0 A method for manufacturing a sealed can body, characterized by the following:

14. A method for manufacturing a sealed can body, comprising a lid, a body, and a weld metal for joining the lid and the body, A process of forming the body by processing stainless steel material, A process of forming the cover by processing a plated steel material having a Ni-based plating layer on the surface of a base steel material, A step of joining the lid and the body by welding, Includes, When the average Cr content of the weld metal is [Cr] and the average Ni content of the weld metal is [Ni], the condition [Cr] + 4 × [Ni] ≥ 5.0 is satisfied. A method for manufacturing a sealed can body, characterized by the following:

15. The processing of the fuselage is welding. A method for manufacturing a sealed can body according to claim 14, characterized in that it is a product of the present invention.

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