Method and apparatus for manufacturing cylindrical members, method for manufacturing metal cans, and method for manufacturing batteries

Abstract

The present invention provides a method for manufacturing cylindrical members that can be produced even if the axial length is relatively large, and that can improve the flatness of the long side wall. [Solution] The method for manufacturing the cylindrical member (10) comprises the steps of: preparing a metal plate (30); clamping the portion of the metal plate (30) that will become the short side wall (12a) with a first mold (21) and a second mold (22), and bending the metal plate (30) by rotating the third mold (23a, 23b) around a rotation axis (A) while the third mold (23a, 23b) is in contact with the portion of the metal plate (30) that will become the long side wall (13a, 13b), thereby obtaining an intermediate molded product (10i) including the short side wall (12a), bent portions (14a, 14b), and long side walls (13a, 13b); and joining the edge portions (16a, 16b) of the intermediate molded product (10i) to form the short side wall (12b).

Description

[Technical Field]

[0001] This disclosure relates to a method for manufacturing a cylindrical member and an apparatus for manufacturing such a member. Furthermore, this disclosure relates to a method for manufacturing a metal can and a method for manufacturing a battery. [Background technology]

[0002] For automotive or stationary batteries, rectangular metal cans are widely used as battery cases. A metal can includes, for example, a cylindrical member having a bottomed rectangular tube shape and a lid. The cylindrical member of a metal can is generally formed by deep drawing of a metal sheet. For example, as described in Patent Document 1, when manufacturing the cylindrical member, the metal sheet used as the material is subjected to multi-stage deep drawing. In Patent Document 1, a first intermediate cup body having a substantially elliptical cross-section is formed from a metal sheet by deep drawing. Next, a second intermediate cup body is formed from the first intermediate cup body by multi-stage re-drawing. The second intermediate cup body has a substantially elliptical cross-section in which the ratio of the minor axis to the major axis (minor axis / major axis) is smaller than that of the first intermediate cup body. Subsequently, the cylindrical member is manufactured by re-drawing and multi-stage ironing of the second intermediate cup body. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 4119612 [Overview of the project] [Problems that the invention aims to solve]

[0004] As described in Patent Document 1, in a metal can used as a battery case, a lid is joined to a bottomed cylindrical member, and terminals are provided on the lid. The lid is positioned on the top of the metal can. In particular, in batteries used in automobiles, a lid with terminals is often provided on the top of the metal can. However, in recent years, from the viewpoint of improving the freedom of vehicle design, there has been a growing need for a lateral terminal structure in batteries used in automobiles, in which terminals are positioned at the longitudinal end. On the other hand, when forming a cylindrical member for a lateral terminal structure by deep drawing, the longitudinal direction of the battery becomes the direction of the drawing depth (axial direction of the cylindrical member), and the drawing depth increases. Therefore, it is difficult to form a cylindrical member by deep drawing.

[0005] For automotive batteries, cooling the battery from the wide, elongated sidewall of the metal can is being considered as a measure to prevent overheating of the electrodes during rapid charging. Specifically, a cooling material that allows a refrigerant to pass through is being considered to be in contact with the elongated sidewall of the metal can, which can secure a larger contact area. From the viewpoint of improving cooling efficiency, it is necessary to make the contact between the elongated sidewall and the cooling material as close as possible, so it is preferable that the elongated sidewall has a high degree of flatness.

[0006] The object of this disclosure is to provide a method for manufacturing a cylindrical member that can be produced even if the axial length is relatively large and that can improve the flatness of the long side wall. [Means for solving the problem]

[0007] The manufacturing method according to this disclosure is a method for manufacturing a cylindrical member. The cylindrical member includes a pair of short side walls and a long side wall. The pair of short side walls face each other. The long side wall is connected to one of the short side walls via a first bend and to the other of the short side walls via a second bend. The long side wall has a width greater than the width of each of the short side walls. The manufacturing method for the cylindrical member includes the steps of: preparing a metal plate; bending the metal plate by clamping a portion of the metal plate that will become one of the short side walls with a first mold and a second mold, and rotating the third mold around a predetermined axis of rotation while the third mold is in contact with the portion of the metal plate that will become the long side wall from the second mold side, and clamping the portion that will become the long side wall with the first mold and the third mold to obtain an intermediate molded product including one of the short side walls, a first bend, and the long side wall; and joining the edges of the intermediate molded product to form the other of the short side walls. [Effects of the Invention]

[0008] According to the method for manufacturing a cylindrical member described herein, even cylindrical members with a relatively large axial length can be manufactured, and the flatness of the long side wall can be improved. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a perspective view of the cylindrical member. [Figure 2] Figure 2 is a cross-sectional view taken along line II-II of the cylindrical member shown in Figure 1. [Figure 3A] Figure 3A is a perspective view showing the schematic configuration of the manufacturing apparatus according to the first embodiment. [Figure 3B] Figure 3B is another perspective view showing the schematic configuration of the manufacturing apparatus according to the first embodiment. [Figure 4A] Figure 4A is a cross-sectional view of the manufacturing apparatus according to the first embodiment. [Figure 4B] Figure 4B is a partially enlarged cross-sectional view of the manufacturing apparatus shown in Figure 4A. [Figure 5A] Figure 5A is a schematic diagram illustrating the manufacturing method of the cylindrical member according to the first embodiment. [Figure 5B]FIG. 5B is a schematic diagram for explaining a method of manufacturing a cylindrical member according to the first embodiment. [Figure 5C] FIG. 5C is a schematic diagram for explaining a method of manufacturing a cylindrical member according to the first embodiment. [Figure 5D] FIG. 5D is a schematic diagram for explaining a method of manufacturing a cylindrical member according to the first embodiment. [Figure 5E] FIG. 5E is a schematic diagram for explaining a method of manufacturing a cylindrical member according to the first embodiment. [Figure 5F] FIG. 5F is a schematic diagram for explaining a method of manufacturing a cylindrical member according to the first embodiment. [Figure 5G] FIG. 5G is a schematic diagram for explaining a method of manufacturing a cylindrical member according to the first embodiment. [Figure 6A] FIG. 6A is a schematic diagram for explaining a method of manufacturing a metal can according to the first embodiment. [Figure 6B] FIG. 6B is a schematic diagram for explaining a method of manufacturing a metal can according to the first embodiment. [Figure 7A] FIG. 7A is a schematic diagram for explaining a method of manufacturing a battery according to the first embodiment. [Figure 7B] FIG. 7B is a schematic diagram for explaining a method of manufacturing a battery according to the first embodiment. [Figure 8A] FIG. 8A is a schematic diagram for explaining the operation of a manufacturing apparatus according to the first embodiment. [Figure 8B] FIG. 8B is a schematic diagram for explaining the operation of a manufacturing apparatus according to the first embodiment. [Figure 8C] FIG. 8C is a schematic diagram for explaining the operation of a manufacturing apparatus according to the first embodiment. [Figure 8D] FIG. 8D is a schematic diagram for explaining the operation of a manufacturing apparatus according to the first embodiment. ? [[ID=4?]] [Figure 9] FIG. 9 is a cross-sectional view of a manufacturing apparatus according to a modification of the first embodiment. [Figure 10A] FIG. 10A is a schematic diagram for explaining the operation of the manufacturing apparatus shown in FIG. 9. [Figure 10B] It seems there is an issue with the "ID=4?" in the original text. Please check and correct it if needed for a more accurate translation.Figure 10B is a schematic diagram illustrating the operation of the manufacturing apparatus shown in Figure 9. [Figure 11] Figure 11 is a cross-sectional view of the manufacturing apparatus according to the second embodiment. [Figure 12A] Figure 12A is a schematic diagram illustrating the manufacturing method of a cylindrical member according to the second embodiment. [Figure 12B] Figure 12B is a schematic diagram illustrating the manufacturing method of a cylindrical member according to the second embodiment. [Figure 13A] Figure 13A is a schematic diagram illustrating the manufacturing method of the cylindrical member in the comparative example. [Figure 13B] Figure 13B is a schematic diagram illustrating the manufacturing method of the cylindrical member in the comparative example. [Figure 13C] Figure 13C is a schematic diagram illustrating the manufacturing method of the cylindrical member in the comparative example. [Figure 13D] Figure 13D is a schematic diagram illustrating the manufacturing method of the cylindrical member in the comparative example. [Modes for carrying out the invention]

[0010] Methods for forming a cylindrical member that includes a short side wall and a long side wall wider than the short side wall include, for example, straightening a circular tube into a rectangular tube shape, and bending a metal plate multiple times and then joining the edges of the metal plate together.

[0011] When straightening a circular tube into a rectangular tube, for example, an upper jig and a lower jig are placed inside the circular tube, and the upper jig is pulled upward while the lower jig is fixed. In this method, the circular tube is formed into a rectangular tube simply by pulling it vertically with the upper and lower jigs, and there is no mechanism to keep the long side walls flat. Therefore, it is difficult to ensure a high degree of flatness of the long side walls.

[0012] On the other hand, when bending a metal sheet, methods generally known as L-bending or V-bending are used. In L-bending, the metal sheet is bent into an L-shape by pressing a die against the other part of the metal sheet while holding down a portion of it. In V-bending, the metal sheet is bent by pressing a V-shaped die against it. When forming a cylindrical member from a metal sheet using L-bending or V-bending, in either method, the area of ​​sliding between the die and the wide, long sidewall becomes larger, and tensile residual stress due to sliding tends to increase on the surface of the long sidewall. This residual stress becomes the driving force for springback of the long sidewall, which can reduce the flatness of the long sidewall.

[0013] The inventors considered that when bending a metal plate, the flatness of the long side wall can be improved by reducing the sliding between the long side wall and the mold. Based on this, the inventors conducted further studies and completed a method for manufacturing a cylindrical member according to the embodiment.

[0014] The manufacturing method according to the embodiment is a method for manufacturing a cylindrical member. The cylindrical member includes a pair of short side walls and a long side wall. The pair of short side walls face each other. The long side wall is connected to one of the short side walls via a first bend and to the other of the short side walls via a second bend. The long side wall has a width greater than the width of each of the short side walls. The manufacturing method for the cylindrical member includes the steps of: preparing a metal plate; bending the metal plate by clamping the portion of the metal plate that will become one of the short side walls with a first mold and a second mold, and rotating the third mold around a predetermined axis of rotation while the third mold is in contact with the portion of the metal plate that will become the long side wall from the second mold side, and clamping the portion that will become the long side wall with the first mold and the third mold to obtain an intermediate molded product including one of the short side walls, a first bend, and the long side wall; and joining the edges of the intermediate molded product to form the other of the short side wall (first configuration).

[0015] In the manufacturing method relating to the first configuration, a die (third die) is brought into contact with the portion of the metal sheet that will become the long side wall of the cylindrical member, and the third die is rotated around a rotation axis in this state, thereby bending the metal sheet and forming the long side wall. In this case, sliding between the third die and the long side wall is less likely to occur, so the stress applied to the long side wall due to sliding can be reduced. As a result, residual stress on the surface of the long side wall is reduced, and springback of the long side wall is suppressed. As a result, the flatness of the long side wall, which is wider than that of the short side wall, can be improved.

[0016] In the first configuration, a cylindrical member is manufactured from a metal sheet using bending rather than drawing. By employing bending, even cylindrical members with relatively large axial lengths can be easily manufactured. Such cylindrical members can be applied, for example, to battery cans with a lateral terminal structure.

[0017] In the manufacturing method relating to the first configuration, in the step of obtaining an intermediate molded product, it is preferable that the third mold rotates around a rotation axis located outside the first bending portion (second configuration).

[0018] In the manufacturing method relating to the second configuration, the third mold rotates around a rotation axis located outside the bend (first bend) between one of the short sidewalls and the long sidewall. In this case, the vicinity of the portion of the metal sheet that becomes the first bend is away from the third mold and does not come into contact with the third mold, at least during the initial stages of forming the first bend. Towards the end of forming the first bend, the metal sheet comes into contact with the third mold near the first bend, while it ceases to come into contact with the third mold in the middle of the long sidewall. That is, in the portion of the metal sheet that is formed into the long sidewall, as the forming of the first bend progresses, the contact position between the metal sheet and the third mold changes to cause the material to flow towards the first bend. As a result, on the outer surface of the intermediate molded product immediately after the forming process, tensile stress is generated in the first bend, and compressive stress is generated in the portion of the long sidewall adjacent to the first bend. Also, on the inner surface of the intermediate molded product immediately after the forming process, compressive stress is generated in the first bend, and tensile stress is generated in the portion of the long sidewall adjacent to the first bend. When the intermediate molded product is removed from the first, second, and third molds, the stress is reversed and released in the first bend and the portion of the long sidewall adjacent to the first bend, and the stresses in the first bend and the portion of the long sidewall adjacent to the first bend cancel each other out. As a result, the springback of the long sidewall is further suppressed, and the flatness of the long sidewall can be further improved.

[0019] In the manufacturing method relating to the first or second configuration, in the step of obtaining an intermediate molded product, a second bent portion can be formed in the intermediate molded product by bending the edge portion of the metal plate relative to the long side wall with a fourth mold (third configuration).

[0020] In the manufacturing method relating to the third configuration, the first bend connecting the long sidewall to one short sidewall and the second bend connecting the long sidewall to the other short sidewall are formed in the same process. Therefore, compared to the case where the second bend is formed in a separate process from the first bend, the number of processes required to manufacture the cylindrical member can be reduced.

[0021] A method for manufacturing a metal can according to the embodiment comprises the steps of manufacturing a cylindrical member by a manufacturing method according to any one of the first to third configurations, and joining a lid to the axial end of the cylindrical member (fourth configuration).

[0022] A battery manufacturing method according to the embodiment comprises the steps of manufacturing a cylindrical member as a material for a battery case by a manufacturing method according to any of the first to third configurations, and joining lids to both axial ends of the cylindrical member (fifth configuration).

[0023] The manufacturing apparatus for a cylindrical member according to the embodiment comprises a first mold, a second mold, and a third mold. The first mold includes a top surface, a shoulder, and a side surface. The shoulder is continuous with the top surface. The side surface is connected to the top surface via the shoulder. The second mold includes a pressing surface. The pressing surface corresponds to the top surface of the first mold. The third mold includes a molding surface. The molding surface corresponds to the side surface of the first mold. The third mold is located near the shoulder of the first mold and is configured to be rotatable about a rotation axis extending in the direction of extension of the shoulder (sixth configuration).

[0024] In the manufacturing apparatus according to the sixth configuration, it is preferable that the rotating shaft is located on the outside of the shoulder portion (seventh configuration).

[0025] The manufacturing apparatus according to the sixth or seventh configuration may further include a fourth mold. The fourth mold may be positioned on the opposite side of the second mold from the first mold. The fourth mold may be configured to be movable, for example, in the thickness direction of the first mold (eighth configuration).

[0026] Embodiments of this disclosure will be described below with reference to the drawings. In these drawings, the same or equivalent components are denoted by the same reference numerals, and the same description will not be repeated.

[0027] <First Embodiment> [Cylindrical member] Figure 1 is a perspective view of a cylindrical member 10 manufactured by the manufacturing method according to this embodiment. As shown in Figure 1, the cylindrical member 10 has a substantially rectangular tubular shape. The cylindrical member 10 can be used, for example, in a battery can. The cylindrical member 10 is formed by bending a metal plate and then joining the edges of the metal plates together. Therefore, the cylindrical member 10 includes a joint 11. The joint 11 is typically a welded joint.

[0028] The cylindrical member 10 includes a pair of short side walls 12a, 12b, a pair of long side walls 13a, 13b, and bent portions 14a, 14b, 15a, 15b.

[0029] The short side walls 12a and 12b are arranged to face each other. In this embodiment, a joint 11 is provided on the short side wall 12b. The joint 11 extends, for example, in the axial direction of the cylindrical member 10 across the entire length of the short side wall 12b.

[0030] The long side walls 13a and 13b are arranged to face each other. The long side wall 13a is connected to one short side wall 12a via a bent portion 14a and to the other short side wall 12b via a bent portion 15a. On the opposite side of the long side wall 13a, the long side wall 13b is connected to one short side wall 12a via a bent portion 14b and to the other short side wall 12b via a bent portion 15b. The bent portions 14a and 15a are corner portions between the short side walls 12a and 12b and the long side wall 13a, respectively. Each of the bent portions 14a, 14b, 15a, and 15b has, for example, a curved shape that is convex outward from the cylindrical member 10.

[0031] Figure 2 is a cross-sectional view (section II-II in Figure 1) of the cylindrical member 10 when cut by a plane perpendicular to the axial direction. Referring to Figure 2, the short side walls 12a, 12b and the long side walls 13a, 13b each have a flat plate shape. More specifically, each of the short side walls 12a, 12b and the long side walls 13a, 13b has a substantially rectangular flat plate shape. However, the width W of the short side walls 12a, 12b is equal to the width W of the short side walls 12a, 12b. Sa width W greater than L having.

[0032] The width W of the long side wall 13a L is the width of the long side wall 13a including the bent portions 14a and 15a, and can be the distance from the R stop on the short side wall 12a side of the bent portion 14a to the R stop on the short side wall 12b side of the bent portion 15a on the outer surface of the cylindrical member 10. Similarly, the width W of the long side wall 13b L is the width of the long side wall 13b including the bent portions 14b and 15b, and can be the distance from the R stop on the short side wall 12a side of the bent portion 14b to the R stop on the short side wall 12b side of the bent portion 15b on the outer surface of the cylindrical member 10. The long side walls 13a and 13b usually have a substantially equal width W L having. The width W of the long side walls 13a and 13b L is, for example, 80 mm or more and 110 mm or less.

[0033] The width W of the short side wall 12a S is the width of the short side wall 12a including the bent portions 14a and 14b, and can be the distance from the R stop on the long side wall 13a side of the bent portion 14a to the R stop on the long side wall 13b side of the bent portion 14b on the outer surface of the cylindrical member 10. Similarly, the width W of the short side wall 12b S is the width of the short side wall 12b including the bent portions 15a and 15b, and can be the distance from the R stop on the long side wall 13a side of the bent portion 15a to the R stop on the long side wall 13b side of the bent portion 15b on the outer surface of the cylindrical member 10. The short side walls 12a and 12b usually have a substantially equal width W L having. The width W of the short side walls 12a and 12b S is, for example, 20 mm or more and 50 mm or less.

[0034] In the axial direction of the cylindrical member 10, the lengths of the long side walls 13a and 13b are substantially equal to the lengths of the short side walls 12a and 12b. The lengths of the long side walls 13a and 13b and the short side walls 12a and 12b in the axial direction of the cylindrical member 10 are, for example, 150 mm or more and 500 mm or less.

[0035] [Manufacturing apparatus] Figures 3A and 3B are perspective views showing the schematic configuration of the manufacturing apparatus 20 according to this embodiment. The cylindrical member 10 (Figure 1) is manufactured, for example, using the manufacturing apparatus 20. The manufacturing apparatus 20 includes a first mold 21, a second mold 22, and third molds 23a and 23b. The manufacturing apparatus 20 may further include fourth molds 24a and 24b.

[0036] Referring to Figure 3A, in the manufacturing apparatus 20, the first mold 21 is positioned on the opposite side of the second mold 22 and the third molds 23a, 23b. The first mold 21 is positioned, for example, above or below the second mold 22 and the third molds 23a, 23b. The first mold 21 may be attached to a mold holder 251. The second mold 22 and the third molds 23a, 23b may be attached to other mold holders 252.

[0037] The first mold 21 is capable of moving relatively closer to and further away from the second mold 22 and the third molds 23a and 23b. For example, the first mold 21 moves relatively closer to or further away from the second mold 22 and the third molds 23a and 23b in the vertical direction. The first mold 21 may move closer to or further away from the second mold 22 and the third molds 23a and 23b by moving itself, or it may move closer to or further away from the second mold 22 and the third molds 23a and 23b by moving themselves.

[0038] In this embodiment, the second mold 22 and the third molds 23a and 23b are arranged on a mold holder 252. The third mold 23a is positioned adjacent to the second mold 22. The third mold 23b is positioned adjacent to the second mold 22 on the opposite side of the third mold 23a. The third molds 23a and 23b are each configured to be rotatable around a rotation axis A.

[0039] In the example shown in Figure 3A, support members 26a are connected to both longitudinal ends of the third mold 23a. Similarly, support members 26b are connected to both longitudinal ends of the third mold 23b. The third molds 23a and 23b are supported on the mold holder 251 by support members 26a and 26b, respectively. Each of the support members 26a and 26b includes a shaft portion 261. Each of the support members 26a and 26b is mounted on the mold holder 251 so as to be rotatable around the central axis of the shaft portion 261. The third mold 23a can rotate together with the support members 26a around the axis of rotation A, with the central axis of the shaft portion 261 being the axis of rotation A. The third mold 23b can rotate together with the support members 26b around the axis of rotation A, with the central axis of the shaft portion 261 being the axis of rotation A.

[0040] Figure 3B is a view of the first mold 21 from the side of the second mold 22 and the third molds 23a, 23b. Referring to Figures 3A and 3B, the first mold 21 is supported by the mold holder 251. In this embodiment, the first mold 21 is supported by the mold holder 251 via an elastic member 27. The elastic member 27 is, for example, a spring or a fluid pressure cylinder.

[0041] In this embodiment, cams 28 are provided on both sides of the longitudinal direction of the first mold 21. The cams 28 can protrude toward the second mold 22 and the third molds 23a and 23b relative to the first mold 21 by the contraction of the elastic member 27. Each of the cams 28 is inserted between a support member 26a connected to the third mold 23a and a support member 26b connected to the third mold 23b, thereby rotating the third molds 23a and 23b and the support members 26a and 26b around the rotation axis A.

[0042] As shown in Figure 3B, the fourth molds 24a and 24b are positioned on the opposite side of the second mold 22 and the third molds 23a and 23b (Figure 3A), similar to the first mold 21. In this embodiment, the fourth molds 24a and 24b are supported by a mold holder 251. The fourth molds 24a and 24b are positioned on both sides of the first mold 21 in the thickness direction. The fourth molds 24a and 24b are configured to be movable in the thickness direction of the first mold 21. Each of the fourth molds 24a and 24b may be moved by an actuator 29, such as a hydraulic unit.

[0043] The configuration of the manufacturing apparatus 20 will be described in more detail below with reference to Figures 4A and 4B. Figure 4A is a cross-sectional view of the manufacturing apparatus 20. Figure 4B is a partially enlarged view of the cross-section of the manufacturing apparatus 20 shown in Figure 4A. The cross-section of the manufacturing apparatus 20 and its components is the cross-section obtained when the manufacturing apparatus 20 is cut by a plane perpendicular to the longitudinal direction of the first mold 21. The longitudinal direction of the first mold 21 corresponds to the axial direction of the cylindrical member 10 (Figures 1 and 2) manufactured by the manufacturing apparatus 20. The thickness direction of the first mold 21 corresponds to the width direction of the short side walls 12a, 12b (Figures 1 and 2) of the cylindrical member 10. The height direction of the first mold 21 corresponds to the width direction of the long side walls 13a, 13b (Figures 1 and 2) of the cylindrical member 10.

[0044] In Figures 4A and 4B, for the sake of clarity, only the first mold 21, the second mold 22, the third molds 23a and 23b, and the fourth molds 24a and 24b are shown, and other components included in the manufacturing apparatus 20 are omitted from the illustration. Also, in Figures 4A and 4B, the second mold 22 and the third molds 23a and 23b are positioned above, and the first mold 21 and the fourth molds 24a and 24b are positioned below.

[0045] First, referring to Figure 4A, the first mold 21 includes a top surface 211, shoulder portions 212a, 212b, and side surfaces 213a, 213b. The first mold 21 may further include a bottom surface 214 and shoulder portions 215a, 215b.

[0046] The top surface 211 is a surface substantially perpendicular to the height direction of the first mold 21. The top surface 211 extends in the longitudinal direction of the first mold 21. The shoulders 212a and 212b are located on both sides of the top surface 211 in a cross-sectional view of the first mold 21. The shoulders 212a and 212b are each continuous with the top surface 211 and extend along the top surface 211 in the longitudinal direction of the first mold 21. The shoulders 212a and 212b may each have an arc shape in a cross-sectional view of the first mold 21. One side surface 213a is connected to the top surface 211 via the shoulder 212a. The other side surface 213b is connected to the top surface 211 via the shoulder 212b.

[0047] The bottom surface 214 is located on the opposite side of the top surface 211 in the height direction of the first mold 21. The bottom surface 214 is connected to the side surface 213a via the shoulder portion 215a. The bottom surface 214 is connected to the side surface 213b via the shoulder portion 215b. The shoulder portions 215a and 215b may each have an arc shape in a cross-sectional view of the first mold 21. The bottom surface 214 and the shoulder portions 215a and 215b, like the top surface 211 and the shoulder portions 212a and 212b, extend in the longitudinal direction of the first mold 21.

[0048] The second mold 22 includes a pressing surface 221. The pressing surface 221 corresponds to the top surface 211 of the first mold 21. The pressing surface 221 is configured to be able to mold one of the short side walls 12a (Figures 1 and 2) of the cylindrical member 10 together with the top surface 211 of the first mold 21.

[0049] The third molds 23a and 23b each include a molding surface 231. The molding surface 231 of the third mold 23a corresponds to one side surface 213a of the first mold 21. The molding surface 231 of the third mold 23a is configured to mold one long side wall 13a (Figures 1 and 2) of the cylindrical member 10 together with the side surface 213a of the first mold 21. The molding surface 231 of the third mold 23b corresponds to the other side surface 213b of the first mold 21. The molding surface 231 of the third mold 23b is configured to mold the other long side wall 13b (Figures 1 and 2) of the cylindrical member 10 together with the side surface 213b of the first mold 21.

[0050] Referring to Figure 4B, as described above, each of the third molds 23a and 23b is configured to be rotatable around the rotation axis A. The rotation axis A of the third mold 23a is located near the shoulder portion 212a of the first mold 21 and is a virtual axis extending in the direction of extension of the shoulder portion 212a. It is preferable that the rotation axis A of the third mold 23a be located outside the shoulder portion 212a of the first mold 21. Specifically, in the cross-section of the manufacturing apparatus 20, it is preferable that the rotation axis A is positioned at the intersection of a virtual line obtained by translating the top surface 211 outward in the height direction of the first mold 21 by the thickness t1 of the short side wall 12a (Figures 1 and 2) of the cylindrical member 10, and a virtual line obtained by translating the side surface 213a outward in the thickness direction of the first mold 21 by the thickness t2 of the long side wall 13a (Figures 1 and 2) of the cylindrical member 10.

[0051] The rotation axis A of the third mold 23b is located near the shoulder portion 212b of the first mold 21 and is a virtual axis extending in the direction of extension of the shoulder portion 212b. It is preferable that the rotation axis A of the third mold 23b is also located outside the shoulder portion 212b of the first mold 21. Specifically, in the cross-section of the manufacturing apparatus 20, it is preferable that the rotation axis A is positioned at the intersection of a virtual line obtained by translating the top surface 211 outward in the height direction of the first mold 21 by the thickness t1 of the short side wall 12a (Figures 1 and 2) of the cylindrical member 10, and a virtual line obtained by translating the side surface 213b outward in the thickness direction of the first mold 21 by the thickness t2 of the long side wall 13b (Figures 1 and 2) of the cylindrical member 10.

[0052] Returning to Figure 4A, the fourth molds 24a and 24b are positioned on the opposite side of the second mold 22 from the first mold 21. The fourth molds 24a and 24b are positioned side by side in the thickness direction of the first mold 21. As described above, the fourth molds 24a and 24b are each configured to be movable in the thickness direction of the first mold 21. The fourth molds 24a and 24b are configured to move closer to and further apart from each other in the thickness direction of the first mold 21.

[0053] [Method for manufacturing cylindrical members] Next, a method for manufacturing the cylindrical member 10 using the manufacturing apparatus 20 will be described with reference to Figures 5A to 5G. The manufacturing method according to this embodiment comprises a preparation step, a molding step, and a joining step.

[0054] (preparation process) Referring to Figure 5A, the preparation step involves preparing the metal plate 30.

[0055] The metal plate 30 is, for example, a steel plate. The metal plate 30 may be a stainless steel plate or a surface-treated steel plate. Surface-treated steel plates include plated steel plates. When the manufactured cylindrical member 10 (Figure 1) is used in a battery can, the surface-treated steel plate is preferably a nickel-plated steel plate. Alternatively, when the cylindrical member 10 is used in a battery can, the metal plate 30 is preferably a stainless steel plate. However, the metal plate 30 may be a plate material made of aluminum, titanium, copper, or an alloy thereof. The front and back surfaces of the metal plate 30 may be covered with, for example, a resin layer.

[0056] The thickness of the metal plate 30 can be appropriately determined depending on the intended use of the cylindrical member 10 (Figure 1) to be manufactured. When the cylindrical member 10 is used in a battery can, the thickness of the metal plate 30 is, for example, 0.1 mm or more and 3.0 mm or less. When the metal plate 30 is a steel plate and the cylindrical member 10 is used in a battery can, the thickness of the metal plate 30 is preferably 0.1 mm or more and 2.0 mm or less.

[0057] (molding process) As shown in Figures 5B to 5F, in the molding process, an intermediate molded product 10i is formed from the metal sheet 30. In the molding process, the portion of the metal sheet 30 that will become the short side wall 12a is held between the first mold 21 and the second mold 22, and the third molds 23a and 23b are brought into contact with the portions of the metal sheet 30 that will become the long side walls 13a and 13b from the second mold 22 side, respectively, and the third molds 23a and 23b are rotated around the rotation axis A to bend the metal sheet 30. Then, the portions that will become the long side walls 13a and 13b are held between the first mold 21 and the third molds 23a and 23b to obtain the intermediate molded product 10i.

[0058] Referring to Figure 5B for more details, when the molding process is started, the metal plate 30 is placed between the first mold 21 and the second mold 22. The third molds 23a and 23b face the metal plate 30 on the second mold 22 side. If the first mold 21 is located below the second mold 22, the metal plate 30 may be placed on the top surface 211 of the first mold 21. If the first mold 21 is located above the second mold 22, the metal plate 30 may be placed on the pressing surface 221 of the second mold 22.

[0059] Referring to Figure 5C, the first mold 21, the second mold 22, and the third molds 23a and 23b are brought relatively close together, and the portion of the metal plate 30 that will become the short side wall 12a is sandwiched between the first mold 21 and the second mold 22. The metal plate 30 is pressed down by the top surface 211 of the first mold 21 and the pressing surface 221 of the second mold 22.

[0060] Referring to Figure 5D, with the portion of the metal plate 30 that will become the short sidewall 12a being held between the first mold 21 and the second mold 22, the rotation of the third molds 23a and 23b is started. The third mold 23a contacts the portion of the metal plate 30 that will become the long sidewall 13a with its forming surface 231 and starts rotating around the rotation axis A in that state. The third mold 23b contacts the portion of the metal plate 30 that will become the long sidewall 13b with its forming surface 231 and starts rotating around the rotation axis A in that state. As the third molds 23a and 23b rotate around the rotation axis A, the metal plate 30 is bent.

[0061] The third mold 23a continues to rotate around the rotation axis A until the metal plate 30 is sandwiched between the third mold 23a and the side surface 213a of the first mold 21. As shown in Figure 5E, the long side wall 13a is formed when the metal plate 30 is sandwiched between the third mold 23a and the side surface 213a of the first mold 21. When the metal plate 30 is sandwiched between the third mold 23a and the side surface 213a of the first mold 21, the formation of the bent portion 14a between the short side wall 12a and the long side wall 13a is completed. The bent portion 14a can have a shape that follows the shoulder portion 212a of the first mold 21.

[0062] Similarly, the third mold 23b continues to rotate around the rotation axis A until the metal plate 30 is sandwiched between the third mold 23b and the side surface 213b of the first mold 21. As shown in Figure 5E, the long side wall 13b is formed when the metal plate 30 is sandwiched between the third mold 23b and the side surface 213b of the first mold 21. Also, when the metal plate 30 is sandwiched between the third mold 23b and the side surface 213b of the first mold 21, the formation of the bent portion 14b between the short side wall 12a and the long side wall 13b is completed. The bent portion 14b can have a shape that follows the shoulder portion 212b of the first mold 21. This results in an intermediate molded product 10i including the short side wall 12a, the bent portions 14a and 14b, and the long side walls 13a and 13b.

[0063] In this embodiment, during the molding process, the edges of the metal plate 30 are bent relative to the long side walls 13a, 13b by the fourth molds 24a, 24b, thereby forming bent portions 15a, 15b in the intermediate molded product 10i. Specifically, as shown in Figure 5F, with the long side wall 13a sandwiched between the first mold 21 and the third mold 23a, the fourth mold 24a is moved from the outside to the inside in the thickness direction of the first mold 21. As the fourth mold 24a moves, the edges of the metal plate 30 are bent toward the inside in the thickness direction of the first mold 21, and the bent portion 15a is formed. The bent portion 15a can have a shape that follows the shoulder portion 215a on the bottom surface 214 side of the first mold 21.

[0064] Similarly, with the long side wall 13b sandwiched between the first mold 21 and the third mold 23b, the fourth mold 24b is moved from the outside to the inside in the thickness direction of the first mold 21. As the fourth mold 24b moves, the edge portion of the metal plate 30 is bent inward in the thickness direction of the first mold 21, forming the bent portion 15b. The bent portion 15b can have a shape that follows the shoulder portion 215b on the bottom surface 214 side of the first mold 21.

[0065] (Joining process) After the molding process, the intermediate molded product 10i is removed from the manufacturing apparatus 20. Referring to Figure 5G, in the joining process, the edges 16a and 16b of the intermediate molded product 10i are joined together to form the short side wall 12b (Figures 1 and 2). In this embodiment, bent portions 15a and 15b are formed on the intermediate molded product 10i during the molding process, and the edges 16a and 16b of the intermediate molded product 10i are bent relative to the long side walls 13a and 13b. By joining these edges 16a and 16b, the short side wall 12b is formed. This makes it possible to obtain the cylindrical member 10 shown in Figures 1 and 2.

[0066] In the joining process, the edges 16a and 16b are joined, for example, by welding. The edges 16a and 16b may also be joined by continuous welding. Continuous welding is typically laser welding, but may also be, for example, arc welding or electron beam welding. The edges 16a and 16b may also be joined by butt welding of the end faces.

[0067] [Method for manufacturing metal cans and batteries] As shown in Figures 6A and 6B, the cylindrical member 10 can be used in the manufacture of the metal can 40. The manufacturing method of the metal can 40 according to this embodiment comprises a manufacturing step and a joining step.

[0068] Referring to Figure 6A, the manufacturing process involves producing the cylindrical member 10 using the manufacturing method described above. Then, the lid 50 is prepared. Referring to Figure 6B, the joining process involves joining the lid 50 to the axial end of the cylindrical member 10. That is, at least one of the openings 17 provided at both axial ends of the cylindrical member 10 is sealed by the lid 50. The lid 50 is joined to the cylindrical member 10, for example, by welding. This makes it possible to obtain a metal can 40 having a rectangular tubular shape with a lid and / or bottom.

[0069] The cylindrical member 10 can be used in a battery case. That is, as shown in Figures 7A and 7B, the cylindrical member 10 can be used as part of a battery case to manufacture a battery 60. The manufacturing method for the battery 60 according to this embodiment comprises a manufacturing step and a joining step.

[0070] Referring to Figure 7A, the manufacturing process involves producing a cylindrical member 10 as the material for the battery can using the manufacturing method described above. Then, two lids 50 are prepared. Each of the lids 50 has a terminal 51 formed on it. For example, the terminal 51 on one lid 50 is the positive terminal, and the terminal 51 on the other lid 50 is the negative terminal.

[0071] Referring to Figure 7B, in the joining process, the lids 50 are joined to both axial ends of the cylindrical member 10. That is, each of the openings 17 provided at both axial ends of the cylindrical member 10 is sealed by the lids 50. The cylindrical member 10 houses the necessary contents, such as electrodes. Each of the lids 50 is joined to the cylindrical member 10 with its terminals 51 electrically connected to the electrodes inside the cylindrical member 10. Each of the lids 50 is joined to the cylindrical member 10, for example, by welding. This allows the battery 60 to be obtained.

[0072] [effect] In the manufacturing method according to this embodiment, when forming an intermediate molded product 10i including a short side wall 12a, bent portions 14a, 14b, and long side walls 13a, 13b, sliding between the third molds 23a, 23b and the long side walls 13a, 13b is minimized. Specifically, the third mold 23a rotates around the rotation axis A while in contact with the portion of the metal plate 30 that will become the long side wall 13a, and then forms the long side wall 13a by clamping the metal plate 30 together with the first mold 21. Similarly, the third mold 23b rotates around the rotation axis A while in contact with the portion of the metal plate 30 that will become the long side wall 13b, and then forms the long side wall 13b by clamping the metal plate 30 together with the first mold 21. In this case, the long side walls 13a, 13b can be formed without the third molds 23a, 23b sliding significantly against the surface of the metal plate 30. Therefore, the stress applied to the long side walls 13a and 13b due to sliding is reduced. As a result, the residual stress on the surface of the long side walls 13a and 13b is reduced, and the springback of the long side walls 13a and 13b during demolding is suppressed. Consequently, the flatness of the wide long side walls 13a and 13b can be improved.

[0073] In this embodiment, the rotation axis A of the third mold 23a is located outside the shoulder portion 212a of the first mold 21. In other words, the rotation axis A is located outside the bent portion 14a that is formed along the shoulder portion 212a of the first mold 21. In this case, the springback of the long side wall 13a is further suppressed, and the flatness of the long side wall 13a can be further improved.

[0074] More specifically, as shown in Figures 8A and 8B, when the rotation axis A of the third mold 23a is located outside the shoulder portion 212a of the first mold 21, at the stage when the rotation of the third mold 23a begins, that is, in the initial stage of forming the bent portion 14a, the portion P1 of the metal plate 30 near the bent portion 14a is separated from the third mold 23a. On the other hand, the remaining portion P2 of the metal plate 30 is in contact with the third mold 23a.

[0075] Referring to Figure 8C, as the third mold 23a rotates further around the rotation axis A and reaches the mid-stage of forming the bent portion 14a, the portion P2 of the metal plate 30 other than the vicinity of the bent portion 14a is still in contact with the third mold 23a. However, as shown in Figure 8D, when the forming of the bent portion 14a is nearing completion and the third mold 23a approaches the side surface 213a of the first mold 21, the metal plate 30 is in contact with the third mold 23a on the bent portion 14a side and the edge side, while the intermediate portion P3 separates from the third mold 23a.

[0076] Thus, during the process in which the long sidewall 13a is formed by the third mold 23a, the contact position between the third mold 23a and the long sidewall 13a moves toward the bent portion 14a, and as a result, material flows from the long sidewall 13a toward the bent portion 14a. As a result, immediately after the completion of molding, stress opposite to that of the bent portion 14a is generated in the long sidewall 13a in the portion adjacent to the bent portion 14a. Specifically, on the outer surface of the intermediate molded product 10i, tensile stress is generated in the bent portion 14a, and compressive stress is generated in the portion of the long sidewall 13a adjacent to the bent portion 14a. Also, on the inner surface of the intermediate molded product 10i, compressive stress is generated in the bent portion 14a, and tensile stress is generated in the portion of the long sidewall 13a adjacent to the bent portion 14a. When demolding occurs, these stresses are reversed and released, and the stresses in the bent portion 14a and the portion of the long sidewall 13a adjacent to the bent portion 14a cancel each other out. Therefore, springback of the long side wall 13a is less likely to occur, and the long side wall 13a can be given a high degree of flatness.

[0077] In this embodiment, the rotation axis A of the third mold 23b is also located outside the shoulder portion 212b of the first mold 21. In other words, the rotation axis A is located outside the bent portion 14b that is formed along the shoulder portion 212b of the first mold 21. In this case, springback of the long side wall 13b is suppressed, similar to the long side wall 13a, and the flatness of the long side wall 13b can be further improved.

[0078] In this embodiment, the rotation axes A of the third molds 23a and 23b may be located inside the shoulder portions 212a and 212b of the first mold 21, respectively. Specifically, as shown in Figure 9, the rotation axes A of the third molds 23a and 23b may be located at the center of curvature of the shoulder portions 212a and 212b. As a result, during the molding process, the third molds 23a and 23b rotate around the rotation axis A located inside the bent portions 14a and 14b, respectively. In this case as well, since the long side walls 13a and 13b are formed by the rotation of the third molds 23a and 23b while in contact with the metal plate 30, the sliding between the third molds 23a and 23b and the metal plate 30 is reduced, and the flatness of the long side walls 13a and 13b can be improved, compared to methods in which molding is performed while sliding between the mold and the metal plate, such as L-bending or V-bending.

[0079] However, from the viewpoint of ensuring higher flatness, it is preferable that the rotation axis A of the third molds 23a and 23b be located outside the shoulders 212a and 212b of the first mold 21, respectively. For example, as shown in Figures 10A and 10B, when the rotation axis A of the third mold 23a is located inside the shoulder 212a of the first mold 21, the first mold 21 and the third mold 23a maintain a constant distance from the bent portion 14a while the bent portion 14a is being formed, and the portion P1 of the metal plate 30 near the bent portion 14a continues to be in contact with the third mold 23a. Therefore, compared to the case where the rotation axis A is located outside the shoulder 212a of the first mold 21 (Figures 8A to 8D), the sliding load between the third mold 23a and the metal plate 30 near the bent portion 14a increases. In this case, tensile stress is generated on the outer surface of the bent portion 14a and compressive stress is generated on the inner surface of the bent portion 14a, but no opposite stress is generated in the portion of the long side wall 13a adjacent to the bent portion 14a. Therefore, when the rotation axis A of the third mold 23a is located inside the shoulder portion 212a of the first mold 21, the springback of the long side wall 13a is less suppressed and the flatness of the long side wall 13a is lower compared to when the rotation axis A is located outside the shoulder portion 212a. Similarly, when the rotation axis A of the third mold 23b is located inside the shoulder portion 212b of the first mold 21, the springback of the long side wall 13b is less suppressed and the flatness of the long side wall 13b is lower compared to when the rotation axis A is located outside the shoulder portion 212b.

[0080] The manufacturing apparatus 20 according to this embodiment includes a first mold 21, a second mold 22, and a third mold 23a, 23b, as well as a fourth mold 24a, 24b. By using the fourth mold 24a, 24b, after forming the short side wall 12a, the bent portions 14a, 14b, and the long side walls 13a, 13b, the bent portions 15a, 15b can be formed consecutively. In other words, the bent portions 14a, 14b on the short side wall 12a side and the bent portions 15a, 15b on the short side wall 12b side can be formed in the same molding process. This reduces the number of processes required to manufacture the cylindrical member 10.

[0081] In this embodiment, the metal plate 30, which is the material of the cylindrical member 10, may be a steel plate. Steel plates have higher rigidity compared to aluminum alloy plates and the like. Therefore, by forming the cylindrical member 10 from a metal plate 30 that is a steel plate, the rigidity of the cylindrical member 10 can be ensured while making the cylindrical member 10 thinner. As a result, for example, when multiple batteries 60 using cylindrical members 10 as battery cases are arranged, the proportion that the cylindrical member 10 occupies in relation to the mounting space of the batteries 60 can be reduced. Therefore, the space efficiency and energy density of the batteries 60 can be improved.

[0082] <Second Embodiment> Figure 11 is a cross-sectional view of the manufacturing apparatus 20A according to this embodiment. The manufacturing apparatus 20A differs from the manufacturing apparatus 20 according to the first embodiment in that it does not have the fourth molds 24a and 24b.

[0083] Referring to Figures 12A and 12B, if the manufacturing apparatus 20A does not have fourth molds 24a and 24b, the bent portions 15a and 15b are formed on the metal sheet 30 before or after the molding process using the manufacturing apparatus 20A. In this embodiment, the bent portions 15a and 15b are formed on the metal sheet 30 before the molding process. That is, before the molding process, the metal sheet 30 is subjected to a bending process, and the bent portions 15a and 15b are formed by bending both ends of the metal sheet 30. The method for forming the bent portions 15a and 15b on the metal sheet 30 is not particularly limited. For example, the bent portions 15a and 15b may be formed by methods such as L-bending or V-bending, or the bent portions 15a and 15b may be formed using molds that rotate around a predetermined axis of rotation, such as the third molds 23a and 23b.

[0084] As shown in Figure 12A, during the molding process, the metal plate 30 with the bent portions 15a and 15b formed is placed between the first mold 21, the second mold 22, and the third molds 23a and 23b. The metal plate 30 is placed between the first mold 21, the second mold 22, and the third molds 23a and 23b with both end edges facing away from the second mold 22 and the third molds 23a and 23b. Next, the portion of the metal plate 30 that will become the short sidewall 12a is clamped by the first mold 21 and the second mold 22. Then, as shown in Figure 12B, similar to the first embodiment, the third molds 23a and 23b are rotated around the rotation axis A with the third molds 23a and 23b in contact with the portion of the metal plate 30 that will become the long sidewalls 13a and 13b. After that, the intermediate molded product 10i is formed by the third molds 23a and 23b clamping the metal plate 30 together with the first mold 21. The intermediate molded product 10i after the molding process includes a short side wall 12a, bent portions 14a, 14b, long side walls 13a, 13b, and bent portions 15a, 15b. After the molding process, a joining process similar to that of the first embodiment is performed.

[0085] While embodiments relating to this disclosure have been described above, this disclosure is not limited to the embodiments described above, and various modifications are possible as long as they do not deviate from its spirit.

[0086] In each of the above embodiments, the bent portion 14a and the long side wall 13a of the cylindrical member 10 are formed simultaneously with the bent portion 14b and the long side wall 13b. However, the bent portion 14a and the long side wall 13a do not necessarily have to be formed simultaneously with the bent portion 14b and the long side wall 13b. For example, in the molding process of the intermediate molded product 10i, the third mold 23a can be rotated around the rotation axis A to form the bent portion 14a and the long side wall 13a on the metal plate 30, and then the third mold 23b can be rotated around the rotation axis A to form the bent portion 14b and the long side wall 13b on the metal plate 30. Similarly, in the molding process of the intermediate molded product 10i, the third mold 23b can be rotated around the rotation axis A to form the bent portion 14b and the long side wall 13b on the metal plate 30, and then the third mold 23a can be rotated around the rotation axis A to form the bent portion 14a and the long side wall 13a on the metal plate 30.

[0087] In each of the above embodiments, the third molds 23a and 23b are configured to be rotationally driven by the cam 28. However, the mechanism for rotating the third molds 23a and 23b is not limited to this. For example, the third mold 23a may be configured to rotate around the rotation axis A by a motor connected to the shaft portion 261 of the support member 26a. Similarly, the third mold 23b may be configured to rotate around the rotation axis A by a motor connected to the shaft portion 261 of the support member 26b.

[0088] In the embodiments described above, an example was given in which the metal plate 30 is formed into an intermediate molded product 10i by arranging the second mold 22 and the third molds 23a, 23b above and the first mold 21 below. However, the positional relationship between the first mold 21 and the second mold 22 and the third molds 23a, 23b is not limited to this. In the molding process of the intermediate molded product 10i, the first mold 21 may be arranged above the second mold 22 and the third molds 23a, 23b. [Examples]

[0089] The present disclosure will be further described below with reference to examples. However, the present disclosure is not limited to the following examples.

[0090] To confirm the effects of this disclosure, CAE analysis was performed using general-purpose analysis software (LS-DYNA, manufactured by JSOL Corporation). Specifically, after performing a molding analysis of the cylindrical member 10, a springback analysis was performed on the resulting cylindrical member 10.

[0091] In Examples 1 and 2, the same first mold 21, second mold 22, third molds 23a, 23b, and fourth molds 24a, 24b as in the first embodiment were used, and an intermediate molded product 10i (a cylindrical member 10 before the joining process) was formed from a metal sheet 30 in the same manner as in the first embodiment. However, in Example 1, the rotation axis A of the third molds 23a, 23b was positioned inside the bent portions 14a, 14b, while in Example 2, the rotation axis A of the third molds 23a, 23b was positioned outside the bent portions 14a, 14b.

[0092] As a comparative example, an intermediate molded product 10i (a cylindrical member 10 before the joining process) was formed from a metal sheet 30 using a forming method mainly involving L-bending. In the comparative example, as shown in Figures 13A and 13B, first, the metal sheet 30 was bent using the first mold 91 and the second mold 92 to form the bent portions 14a and 14b on the short side wall 12a side. Then, as shown in Figures 13C and 13D, the metal sheet 30 was pressed from both sides of the first mold 91 by the third mold 93, and the bent portions 15a and 15b on the opposite side were formed by the fourth mold 94.

[0093] The common conditions in each example and comparative example are as follows: • Metal sheet (material): Steel sheet with a tensile strength of 340 MPa and a thickness of 0.3 mm. • Shape of the cylindrical member: Width W of the short side wall S = 30mm, width of the long side wall W L = 100 mm, axial length 300 mm, radius of curvature of each bend 2 mm

[0094] In this analysis, the maximum and minimum coordinate values ​​in a direction perpendicular to the flat surface were obtained for the outer surface (top) of the short side wall 12a, the outer surface (bottom) of the short side wall 12b, and one of the outer surfaces (side) of the long side walls 13a and 13b, using the functions of the analysis software described above. The flatness was then evaluated by the difference between these values. A smaller difference in coordinate values ​​indicates higher flatness. The results for each example and comparative example are shown in Table 1.

[0095] [Table 1]

[0096] Table 1 shows the ratio of the difference in coordinate values ​​on the top, bottom, and side surfaces to that of the comparative example. As shown in Table 1, in both Examples 1 and 2, the flatness of the wide side surface was improved compared to the comparative example. In Example 2, where the rotation axis A of the third mold 23a, 23b was positioned outside the bent portions 14a, 14b, the difference in coordinate values ​​on the wide side surface was less than 50% of that of the comparative example, and the flatness of the side surface was significantly improved compared to the comparative example.

[0097] Thus, by manufacturing the cylindrical member 10 using the manufacturing method described herein, the flatness of the wide side surface (long side wall) of the cylindrical member 10 can be improved. Therefore, for example, when the cylindrical member 10 is used in a battery case, the cooling material can be brought into closer contact with the wide side surface of the cylindrical member 10, thereby improving the cooling efficiency of the battery. [Explanation of Symbols]

[0098] 10: Cylindrical member 10i: Intermediate molded product 12a,12b: Short side wall 13a, 13b: Long side wall 14a, 14b: Bent section (first bent section) 15a, 15b: Bent section (second bent section) 16a, 16b: Edge 20,20A: Manufacturing equipment 21: First mold 211:Top surface 212a, 212b: Shoulder 213a, 213b: Side 22: Second mold 221: Pressing surface 23a, 23b: Third mold 231: Molding surface 24a, 24b: Fourth mold 30: Metal plate 40: Metal can 50: Lid 60:Battery

Claims

1. A method for manufacturing a cylindrical member, comprising a pair of opposing short side walls and a long side wall connected to one of the short side walls via a first bend and to the other short side wall via a second bend, the long side wall having a width greater than the width of each of the short side walls, The process of preparing the metal plate, The process involves clamping one of the short sidewalls of the metal plate with the first and second molds, and bending the metal plate by rotating the third mold around a predetermined axis while the third mold is in contact with the portion of the metal plate that will become the long sidewall from the second mold side, thereby clamping the portion that will become the long sidewall with the first and third molds to obtain an intermediate molded product including one of the short sidewalls, the first bent portion, and the long sidewall. A step of joining the edges of the intermediate molded product together to form the other half of the short side wall, A manufacturing method that includes the following features.

2. A manufacturing method according to claim 1, A manufacturing method in which, in the process of obtaining the intermediate molded product, the third mold rotates around the rotation axis located outside the first bend.

3. A manufacturing method according to claim 1, A manufacturing method comprising the step of obtaining the intermediate molded product, in which the edge portion of the metal plate is bent relative to the long side wall by a fourth mold to form the second bent portion of the intermediate molded product.

4. A method for manufacturing a metal can, A step of manufacturing the cylindrical member by the manufacturing method described in any one of claims 1 to 3, The process of joining a lid to the axial end of the cylindrical member, A manufacturing method that includes the following features.

5. A method for manufacturing a battery, A step of manufacturing the cylindrical member as a material for a battery can by the manufacturing method described in any one of claims 1 to 3, The process of joining lids to both ends in the axial direction of the cylindrical member, A manufacturing method that includes the following features.

6. A manufacturing apparatus for cylindrical members, A first mold including a top surface, a shoulder portion continuous with the top surface, and a side surface connected to the top surface via the shoulder portion, A second mold including a pressing surface corresponding to the top surface, A third mold including a molding surface corresponding to the aforementioned side surface, Equipped with, The third mold is located near the shoulder portion and is configured to be rotatable about a rotation axis extending in the direction of extension of the shoulder portion, in the manufacturing apparatus.

7. A manufacturing apparatus according to claim 6, The aforementioned rotating shaft is located on the outside of the shoulder portion of the manufacturing apparatus.

8. The manufacturing apparatus according to claim 6, further, A manufacturing apparatus comprising a fourth mold positioned on the opposite side of the second mold from the first mold and configured to be movable in the thickness direction of the first mold.

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