Double-seamed structure and batteries and cans having the same

Abstract

A double-seamed structure 100 comprises: a first metal member 111 having a first folded-back section 113 at a first end section 112; and a second metal member 121. An airtight seal is maintained though close contact of a first region 115, which includes the first end section 112 of the first metal member 111, and a second region 125, which includes a second end section 122 of the second metal member 121.

Description

[Technical Field]

[0001] The present invention relates to a double seaming structure and a battery and a can having the same. [Background technology]

[0002] Double seaming is known as a method for joining the can body and can lid of a metal container. Double seaming achieves inexpensive and highly reliable sealing. For example, Patent Document 1 discloses the use of double seaming in cases for electrical equipment. Patent Document 1 also discloses that double seaming is performed by sandwiching a stretch film between the can body and the can lid to insulate them. Furthermore, double seaming may require a strong joint that can withstand relatively high internal pressure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-343310 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide an excellent double seaming structure. [Means for solving the problem]

[0005] According to one aspect of the present invention, a double seaming structure comprises a first metal member having a first fold portion at a first end, and a second metal member, wherein a first region including the first end of the first metal member and a second region including the second end of the second metal member are tightly sealed by double seaming. [Effects of the Invention]

[0006] According to the present invention, an excellent double seaming structure can be provided. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a partially cutaway perspective view showing an outline of a configuration example of a battery according to a first embodiment. [Figure 2] FIG. 2 is an end view showing an outline of a configuration example of a double seaming structure of the seaming section according to the first embodiment. [Figure 3] FIG. 3 is a flowchart showing an outline of an example of a method for manufacturing a battery according to the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing an outline of an example of the shape of a can body and a can lid before double seaming. [Figure 5A] FIG. 5A is a diagram illustrating a first method for forming the folded portion. [Figure 5B] FIG. 5B is a diagram illustrating a second method for forming the folded portion. [Figure 6] FIG. 6 is a diagram for explaining double seaming according to the first embodiment. [Figure 7] FIG. 7 is a diagram for explaining the double seaming according to the comparative example. [Figure 8] FIG. 8 is a diagram for explaining a state that may occur when the internal pressure rises in the double seaming structure according to the comparative example. [Figure 9] FIG. 9 is an end view showing an outline of a configuration example of a double seaming structure according to the second embodiment. [Figure 10] FIG. 10 is a diagram for explaining double seaming of the second embodiment. [Figure 11A] FIG. 11A is an end view showing an outline of a configuration example of a double seaming structure according to a first modified example. [Figure 11B] FIG. 11B is an end view showing an outline of another configuration example of the double seaming structure according to the first modified example. [Figure 11C] FIG. 11C is an end view showing an outline of a configuration example of a double seaming structure according to a second modified example. [Figure 11D] FIG. 11D is an end view showing an outline of another configuration example of the double seaming structure according to the second modified example. [Figure 11E] FIG. 11E is an end view showing an outline of a configuration example of a double seaming structure according to a third modified example. [Figure 11F] FIG. 11F is an end view showing an outline of a configuration example of a double seaming structure according to a fourth modified example. [Figure 11G] FIG. 11G is an end view showing an outline of a configuration example of a double seaming structure according to a fifth modified example. [Figure 11H] FIG. 11H is a diagram illustrating a method for forming a folded portion according to the fifth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] [First embodiment] A first embodiment will be described with reference to the drawings. This embodiment relates to a battery. In particular, the battery has a battery container in which a metal can body and a can lid are sealed with a double-seaming structure, and the can body and the can lid are insulated from each other by the double-seaming structure, and each of the can body and the can lid functions as an electrode.

[0009] <Battery structure> FIG. 1 is a partially cutaway perspective view that schematically illustrates an example of the configuration of a battery 1 according to this embodiment. The battery 1 has a structure in which a battery section 9 is housed inside a battery container 2. The battery container 2 includes a can body 3 and a can lid 4, which are joined by a double-seaming structure at a seaming section 5. The battery container 2 is sealed by the can body 3 and the can lid 4 joined by this double-seaming structure. For illustrative purposes, FIG. 1 illustrates a vertical section of the can body 3 and the can lid 4 of the battery container 2, excluding the battery section 9 inside the battery container 2 and the bottom surface 31 of the can body 3.

[0010] The can body 3 has a cylindrical shape with a bottom that is open at the top. The bottom of the can body 3 is referred to as the bottom surface portion 31, and the side surface of the can body 3 is referred to as the cylindrical portion 32. The open top of the can body 3 is closed by a can lid 4. The can lid 4 has a flat surface 41 that closes the opening of the can body 3 and is a flat surface parallel to the bottom surface portion 31, and a joint portion 42 that tightly contacts the cylindrical portion 32 of the can body 3. The bottom surface portion 31 and the flat surface portion 41 may have a shape (for example, a bead, not shown) for improving resistance (rigidity) to deformation due to internal pressure.

[0011] A battery unit 9 is housed in the sealed internal space of the battery container 2. The battery unit 9 may be any type of battery. For example, the battery unit 9 may be a lithium-ion battery. The positive electrode of the battery unit 9 is electrically connected to the can body 3, and the negative electrode is electrically connected to the can lid 4. In this embodiment, the can body 3 and the can lid 4 are insulated by the seaming portion 5. Therefore, the can body 3 functions as the positive electrode, and the can lid 4 functions as the negative electrode. The positive and negative electrodes may be reversed, with the negative electrode of the battery unit 9 connected to the can body and the positive electrode of the battery unit 9 connected to the can lid.

[0012] The size of the battery 1 is not limited to, but may be, for example, about 70 mm in diameter and about 70 mm in height. For example, the can body 3 may be made of nickel-plated steel, and the can lid 4 may be made of aluminum, but is not limited to, the can body 3 may have a thickness of, for example, about 0.2 mm, and the can lid 4 may have a thickness of, for example, about 0.25 mm. Furthermore, the battery container 2 has a pressure resistance of, for example, but is not limited to, about 1 MPa.

[0013] When the batteries 1 are stacked, the can body 3 of the upper battery 1 fits inside the joint 42 that rises around the flat surface 41 of the can lid 4 of the lower battery 1. At this time, the flat surface 41 of the can lid 4 of the lower battery 1 comes into contact with the bottom surface 31 of the can body 3 of the upper battery 1. Because the can body 3 and can lid 4 serve as the positive and negative electrodes, stacking the batteries 1 results in the batteries 1 being connected in series.

[0014] <Double seaming structure> 2 is an end view showing a schematic diagram of a double seaming structure 100 of a seaming section 5 according to a first embodiment. This double seaming structure 100 is formed by a first metal member 111 forming the can body 3 and a second metal member 121 forming the can lid 4. The double seaming structure 100 of this embodiment is basically the same structure as that generally known as a double seaming structure. That is, it is formed by wrapping the curled portion of the can lid 4 around the flange portion of the can body 3 and crimping and joining them, and has a structure in which the second metal member 121 of the can lid 4 and the first metal member 111 of the can body 3 are each double-layered.

[0015] 2, the first metal member 111 of the can body 3 forms a body wall 172 that continues from the cylindrical portion 32 and extends upward, and a body hook 171 that extends downward by being folded back outward from the upper end of the body wall 172. The total length of the body hook 171 and the body wall 172 is, but is not limited to, about 5 to 10 mm, for example.

[0016] The second metal member 121 of the can lid 4 has a cover hook 173 that is arranged to fit between the body hook 171 and the body wall 172 from below, a seaming wall 174 that is folded outward from the lower end of the cover hook 173 and extends upward outside the body hook 171, and a chuck wall 175 that is folded inward from the upper end of the seaming wall 174 and extends downward inside the body wall 172, and the chuck wall 175 is connected to the flat portion 41 of the can lid 4.

[0017] Unlike a typical double seaming structure, the double seaming structure 100 of this embodiment has a first folded portion 113 at the first end 112, which is the end of the first metal member 111, i.e., at the end of the body hook 171. The first folded portion 113 has a folded end shape, also known as hemming, formed by folding the first metal member 111 180° and then flattening it. At the first folded portion 113, the first metal member 111 is bent so that the first end surface 114 of the first metal member 111 is located closer to the body wall 172 than the body hook 171.

[0018] Furthermore, unlike a typical double seaming structure, the double seaming structure 100 of this embodiment has a second folded portion 123, which has a shape similar to that of a hemming bend, at the second end 122, which is the end of the second metal member 121, i.e., at the end of the cover hook 173. At the second folded portion 123, the second metal member 121 is bent so that the second end surface 124 of the second metal member 121 is located closer to the seaming wall 174 than the cover hook 173.

[0019] In this embodiment, the double seaming structure 100 maintains a tight seal between a first region 115 including the first end 112 of the first metal member 111 and a second region 125 including the second end 122 of the second metal member 121. To ensure electrical insulation between the first metal member 111 and the second metal member 121, a first insulating layer 131, which is a coating formed by applying an insulating paint, is provided on the first region 115 of the first metal member 111, including the region in contact with the second metal member 121. Similarly, a second insulating layer 141, which is a coating formed by applying an insulating paint, is provided on the second region 125 of the second metal member 121, including the region in contact with the first metal member 111. In this embodiment, the first metal member 111 and the second metal member 121 function as electrodes of the battery 1, so no insulating layer is provided on at least the portions that function as electrodes.

[0020] In the double seaming structure 100 of this embodiment, the first end surface 114 of the first metal member 111 and the second end surface 124 of the second metal member 121 face each other. Therefore, for insulation, a first insulating layer 131 is provided on the first end surface 114, and a second insulating layer 141 is provided on the second end surface 124. Therefore, in this embodiment, the first insulating layer 131 and the second insulating layer 141 are formed after, for example, punching the material. In the example shown in FIG. 2 , the first insulating layer 131 and the second insulating layer 141 are formed after the first folded portion 113 and the second folded portion 123 are formed. The insulating layer is not limited to being formed directly on the metal member, but may be formed on the metal member after surface processing such as painting or printing has been performed.

[0021] In the double seaming structure 100, the adhesive 151 is solidified at the contact area between the first region 115 and the second region 125. This adhesive 151 is formed by solidifying an anaerobic adhesive that was applied to at least one of the first region 115 and the second region 125 before the double seaming structure 100 was formed.

[0022] Anaerobic adhesives are primarily composed of acrylate monomers, and begin to solidify when they come into contact with metal ions and are protected from air. Anaerobic adhesives that are commonly used to prevent loosening of screws or for connecting pipes can be used. In this embodiment, if the metal ions are insufficient to solidify the anaerobic adhesive, a reaction activator can be used in combination.

[0023] <Battery manufacturing method> The following describes a method for manufacturing the battery 1. Fig. 3 is a flowchart showing an outline of the method for manufacturing the battery according to this embodiment. First, the can body 3 is formed (step S1), and the can lid 4 is formed (step S2).

[0024] Figure 4 is a longitudinal cross-sectional view showing the outline of the shapes of the can body 3 and can lid 4 before double seaming. For the can body 3, as shown in Figure 4(b), a cup-shaped member having a bottom portion 31 and a cylindrical portion 32 is formed. An outwardly expanding flange portion 38 is formed at the upper end portion of the cylindrical portion 32. For the can lid 4, as shown in Figure 4(a), a curled portion 48 is formed at the peripheral edge of the disc-shaped flat portion 41 so as to overlap the flange portion 38 of the can body 3.

[0025] Furthermore, the end of the flange portion 38 is folded back to form a first folded back portion 113. Also, the end of the curled portion 48 is folded back to form a second folded back portion 123. There are several possible folding methods.

[0026] 5A is a diagram illustrating a first method for forming a folded portion. As shown in FIG. 5A(a), a roll 72 having a recess that rotates around a central axis C is pressed against the end of a metal plate 71 to be folded. As a result, the end of the metal plate 71 is folded to the opposite side as shown in FIG. 5A(b). The folded portion is formed by sandwiching the folded portion from above and below.

[0027] 5B is a diagram illustrating a second method for forming the folded portion. As shown in FIG. 5B(a), in a first step, an end of a metal plate 71 placed on a lower mold 73 is pressed downward by an upper mold 74 and bent downward. Subsequently, as shown in FIG. 5B(b), in a second step, the end of the metal plate 71 is sandwiched between a substantially U-shaped lower mold 75 and an upper mold 76 with a flat bottom, whereby the end of the metal plate 71 is bent to the opposite side in the same manner as in FIG. 5A(b). By sandwiching the folded portion from above and below, the folded portion is formed. The formation of the folded-back portion may be carried out before or after the formation of the flange portion 38 of the can body 3 and the curled portion 48 of the can lid 4 .

[0028] Once the can body 3 and the can lid 4 have been formed in the above manner, a resin coating is formed in the area including each end (step S3). That is, resin is applied to the first area 115 of the first end 112 of the can body 3, and when this resin is cured, a coating is formed that will become the first insulating layer 131. Similarly, resin is applied to the second area 125 of the second metal member 121 of the can lid 4, and when this resin is cured, a coating is formed that will become the second insulating layer 141.

[0029] The first insulating layer 131 and the second insulating layer 141 may be formed before the first folded portion 113 and the second folded portion 123 are formed. When the insulating layer is formed before the end portions are folded, unlike the state shown in Fig. 2, the insulating layer is also formed between the folded plates, but the function of the insulating layer is the same.

[0030] Next, a liquid anaerobic adhesive is applied to the flange portion 38 of the can body 3 and the curled portion 48 of the can lid 4, which are areas that will be rolled into the inside of the double seaming structure 100 (step S4). Before applying the liquid anaerobic adhesive to the curled portion 48, a sealing compound that is normally used for general can lids may be applied thereto.

[0031] Next, a separately prepared battery unit 9 is placed inside the can body 3, and the can lid 4 is placed over the opening of the can body 3 (step S5). At this time, the positive electrode of the battery unit 9 is connected to the can body 3, and the negative electrode of the battery unit 9 is connected to the can lid 4.

[0032] Finally, the flange portion 38 of the can body 3 and the curled portion 48 of the can lid 4 are seamed together (step S6). Seaming in this embodiment will be described with reference to FIG. As shown in Figure 6(a), during seaming, the curled portion 48 of the can lid 4 is placed on the flange portion 38 of the can body 3. Here, a first folded-back portion 113 is formed at a first end 112 of a first metal member 111 that forms the flange portion 38. A first insulating layer 131 is formed at a first region 115 of the first metal member 111. A second folded-back portion 123 is formed at a second end 122 of a second metal member 121 that forms the curled portion 48. A second insulating layer 141 is formed at a second region 125 of the second metal member 121.

[0033] In this state, first seaming is performed using the first seaming roll, and the first metal member 111 of the can body 3 and the second metal member 121 of the can lid 4 are rolled together, as shown in Figure 6(b). At this time, the first folded portion 113 of the first metal member 111 slides and rubs against the second insulating layer 141 of the second metal member 121. At the same time, the second folded portion 123 of the second metal member 121 slides and rubs against the first insulating layer 131 of the first metal member 111. In particular, the tip of the first folded portion 113 is rounded, and this portion is coated with a liquid anaerobic adhesive that functions as a lubricant, so the first folded portion 113 slides smoothly over the second insulating layer 141. Similarly, the tip portion of the second folded portion 123 is rounded and coated with a liquid anaerobic adhesive that acts as a lubricant, so that the second folded portion 123 slides smoothly over the first insulating layer 131.

[0034] Next, a second seaming is performed using a second seaming roll, and as shown in Figure 6(c), the first region 115 of the first metal member 111 and the second region 125 of the second metal member 121 are firmly pressed together, forming the double seaming structure 100. Because the air inside the double seaming structure 100 is blocked, the applied anaerobic adhesive solidifies in the double seaming structure 100. This further improves the strength and sealing performance of the double seaming structure 100. In this manner, the battery 1 is manufactured.

[0035] <Regarding the double seaming structure of this embodiment> The double seaming structure 100 according to this embodiment will be further described. In the double seaming structure 100 according to this embodiment, good insulation is maintained by the first insulating layer 131 and the second insulating layer 141. This is due in particular to the first folded portion 113 provided at the first end 112 of the first metal member 111 and the second folded portion 123 provided at the second end 122 of the second metal member 121.

[0036] Fig. 7 is a diagram for explaining double seaming according to a comparative example. Fig. 7 shows an example in which a double seaming structure is formed by the flange portion 38b of the first metal member 111b and the curl portion 48b of the second metal member 121b, where Fig. 7(a) shows the state before seaming, Fig. 7(b) shows the state after the first seaming, and Fig. 7(c) shows the state after the second seaming.

[0037] As shown in Figure 7(a), in this example, the first metal member 111b does not have a folded portion, the first insulating layer 131b is formed in a plate state, and the first end surface 114b is exposed at the first end 112b. Similarly, the second metal member 121b does not have a folded portion, the second insulating layer 141b is formed in a plate state, and the second end surface 124b is exposed at the second end 122b. As indicated by the arrow in Figure 7(a), the first end surface 114b of the first metal member 111b is in contact with the second insulating layer 141b of the second metal member 121b.

[0038] When first seaming is performed in this state, as shown by the arrows in Figure 7(b), the first end surface 114b of the first metal member 111b bites into the second insulating layer 141b of the second metal member 121b, destroying the second insulating layer 141b. Similarly, the second end surface 124b of the second metal member 121b bites into the first insulating layer 131b of the first metal member 111b, destroying the first insulating layer 131b.

[0039] This breakdown of the insulating layer progresses further during the second seaming. As a result, in the double seaming structure 100b completed by the second seaming, electrical insulation is broken between the first end 112b of the first metal member 111b and the second end 122b of the second metal member 121b, and electrical conduction occurs between the first metal member 111b and the second metal member 121b. A container in this state is unsuitable as a battery container as described above.

[0040] In contrast, in the double seaming structure 100 according to this embodiment, the end is rounded by the folded portion, and during manufacturing, this moves smoothly over the insulating layer without damaging the insulating layer. Therefore, in the double seaming structure 100 according to this embodiment, the electrical insulation between the first metal member 111 and the second metal member 121 is well maintained, and the battery container 2 having the double seaming structure 100 according to this embodiment is suitable as a battery container.

[0041] To electrically insulate the first and second metal members, a stretched polymer film may be sandwiched between the metal members. However, stretched polymer films are relatively expensive. In contrast, forming an insulating film using a coating, as in the present embodiment, allows for inexpensive electrical insulation between the first and second metal members. Furthermore, sandwiching a polymer film between the first and second metal members can reduce adhesion between the first and second metal members, potentially resulting in poor sealing performance in a double-seamed structure with a polymer film sandwiched between them. In contrast, the double-seamed structure 100 according to the present embodiment, in which the insulating layer is formed using a coating, also achieves high sealing performance.

[0042] Furthermore, in the double seaming structure 100 of this embodiment, the first folded portion 113 of the first metal member 111 and the second folded portion 123 of the second metal member 121 are made of two layers of metal material, which increases their rigidity. Therefore, the double seaming structure 100 of this embodiment is stronger than a typical double seaming structure such as the double seaming structure 100b of the comparative example.

[0043] Furthermore, the double seaming structure 100 of this embodiment has high pressure resistance. Figure 8 is a diagram illustrating a state that can occur when the internal pressure increases in the double seaming structure 100b according to the comparative example. This situation is particularly likely to occur when the plate thicknesses of the first metal member 111b and the second metal member 121b are thin. That is, when the plate thicknesses of the first metal member 111b and the second metal member 121b are thin, the force that fastens the first metal member 111b and the second metal member 121b to each other in the double seaming structure 100b weakens. As a result, when the internal pressure increases, the body hook 171b comes off, destroying the double seaming structure 100b, as shown in the order of (a) → (b) → (c) in Figure 8.

[0044] In contrast, in the double seaming structure 100 according to the present embodiment, as shown in FIG. 2, the first end 112 of the body hook 171 is bulged by the first folded portion 113, and the second end 122 of the cover hook 173, which contacts the body hook 171, is bulged by the second folded portion 123. These bulges create resistance against each other, and the double seaming structure 100 according to the present embodiment is less likely to cause the body hook 171 to come loose, as occurs in the double seaming structure 100b according to the comparative example shown in FIG. 8. As a result, the double seaming structure 100 according to the present embodiment can achieve higher pressure resistance for the battery container 2 than the double seaming structure 100b according to the comparative example, and the plate thicknesses of the first metal member 111 and the second metal member 121 can be made thinner.

[0045] In this embodiment, in particular, since the first end face 114 and the second end face 124 face each other, the contact between the first end face and the second end face provides a large resistance to deformation. Furthermore, since this effect of increasing pressure resistance can be obtained even if an insulating layer is not provided on the first metal member 111 and the second metal member 121, this configuration can also be applied to applications other than those requiring insulation, such as battery containers.

[0046] Here, we have explained the double seaming structure 100 of this embodiment as an example of using it in a battery container, but it goes without saying that this double seaming structure 100 can also be used to join two metal components in other items, not just batteries.

[0047] [Second embodiment] The second embodiment will be described below, focusing on the differences from the first embodiment, and the same parts will be given the same reference numerals and the description thereof will be omitted.

[0048] 9 is an end view showing an outline of a configuration example of a double seaming structure 102 according to the second embodiment. As shown in FIG. 9, in the double seaming structure 102 according to the second embodiment, the folding directions of the first folded portion 213 of the first metal member 111 and the second folded portion 223 of the second metal member 121 are opposite to those in the first embodiment. That is, the first folded portion 213 is folded so that the first end surface 114 of the first metal member 111 is positioned closer to the seaming wall 174 than the body hook 171. Furthermore, the second folded portion 223 is folded so that the second end surface 124 of the second metal member 121 is positioned closer to the chuck wall 175 than the cover hook 173.

[0049] FIG. 10 is a diagram illustrating the double seaming of the second embodiment. (a), (b), and (c) in FIG. 10 correspond to (a), (b), and (c) in FIG. 6, respectively, and show the states before seaming, after the first seaming, and after the second seaming, respectively. In the second embodiment, during seaming, the first folded portion 213 of the first metal member 111 slides while rubbing against the second insulating layer 141 of the second metal member 121. The tip of the first folded portion 213 is rounded, and a liquid anaerobic adhesive is applied to this portion, allowing the first folded portion 213 to slide smoothly against the second insulating layer 141. At the same time, the second folded portion 223 of the second metal member 121 slides while rubbing against the first insulating layer 131 of the first metal member 111. The tip of the second folded portion 223 is rounded and coated with a liquid anaerobic adhesive, allowing the second folded portion 223 to slide smoothly over the first insulating layer 131. Therefore, in the double seaming structure 102 of this embodiment, as in the double seaming structure 100 of the first embodiment, the first insulating layer 131 and the second insulating layer 141 maintain good electrical insulation between the first metal member 111 and the second metal member 121. Therefore, the battery container 2 having the double seaming structure 102 of this embodiment is also suitable as a battery container.

[0050] Furthermore, in the double seaming structure 102 of this embodiment, the first end 112 of the body hook 171 is bulged by the first folded portion 213, and the second end 122 of the cover hook 173, which contacts the body hook 171, is bulged by the second folded portion 223. These bulges create resistance against each other, making it difficult for the body hook 171 to come loose, even in the double seaming structure 102 of this embodiment. As a result, the double seaming structure 102 of this embodiment can achieve high pressure resistance for the battery container 2 and can reduce the plate thicknesses of the first metal member 111 and the second metal member 121.

[0051] Furthermore, in the double seaming structure 102 according to this embodiment, the first end face 114 of the first metal member 111 and the second end face 124 of the second metal member 121 are not opposed to each other, with the first metal member 111 and the second metal member 121 sandwiched between them. Since there is no contact between the first end face 114 and the second end face 124, insulation is more easily maintained than in the case of the double seaming structure 100 according to the first embodiment.

[0052] Because the first end surface 114 and the second end surface 124 do not face each other, an insulating layer need not be formed on the first end surface 114 and the second end surface 124. Therefore, in this embodiment, the manufacturing method has a higher degree of freedom than in the first embodiment. For example, an insulating coating may be formed on a flat plate, and then the can body 3 and the can lid 4 may be formed using the first metal member 111 and the second metal member 121 that are punched out. In this case, no insulating layer is formed on the first end surface 114 of the punched first metal member 111 and the second end surface 124 of the punched second metal member 121, and the metal is exposed, but the insulation of the double seaming structure 102 is ensured.

[0053] [Variations] Several modifications of the above-described embodiment will be described. Here, differences from the above-described embodiment will be described, and the same parts will be assigned the same reference numerals and descriptions thereof will be omitted.

[0054] First Modified Example FIG. 11A is an end view showing a schematic diagram of a double seaming structure 104a according to a first modification. In the first modification, a first folded portion 113 is formed on the first metal member 111, but no folded portion is formed on the second metal member 121. In this example, a second insulating layer 141 is formed on the second metal member 121, but no insulating film is formed on the first metal member 111. Because the first folded portion 113 is formed on the first end portion 112 of the first metal member 111 and the first end portion 112 is rounded, the second insulating layer 141 is not destroyed during seaming. If the insulation of the second end portion 122 of the second metal member 121 is maintained, the second insulating layer 141 formed on the second metal member 121 ensures insulation between the first metal member 111 and the second metal member 121. Note that an insulating layer may also be formed on the first metal member 111.

[0055] 11A, the first folded portion 113 may be folded so that the first end surface 114 of the first metal member 111 is positioned closer to the body wall 172 than the body hook 171. Alternatively, the first folded portion 213 may be folded so that the first end surface 114 of the first metal member 111 is positioned closer to the seaming wall 174 than the body hook 171, as shown in FIG.

[0056] <Second modified example> FIG. 11C is an end view showing a schematic diagram of a double seaming structure 104b according to a second modified example. In the second modified example, a second folded portion 123 is formed on the second metal member 121, but no folded portion is formed on the first metal member 111. In this example, a first insulating layer 131 is formed on the first metal member 111, but no insulating film is formed on the second metal member 121. Because the second folded portion 123 is formed on the second end portion 122 of the second metal member 121 and the second end portion 122 is rounded, the first insulating layer 131 is not destroyed during seaming. If the insulation of the first end portion 112 of the first metal member 111 is maintained, the first insulating layer 131 formed on the first metal member 111 ensures insulation between the first metal member 111 and the second metal member 121. Note that an insulating layer may also be formed on the second metal member 121.

[0057] 11C, the second folded portion 123 may be folded so that the second end surface 124 of the second metal member 121 is positioned closer to the body hook 171 than the cover hook 173. Alternatively, the second folded portion 223 may be folded so that the second end surface 124 of the second metal member 121 is positioned closer to the body wall 172 than the cover hook 173, as shown in FIG. 11D.

[0058] In the first or second embodiment described above, as in the first or second modified example, insulation may be achieved by only either the first insulating layer 131 or the second insulating layer 141. However, providing both the first insulating layer 131 and the second insulating layer 141 provides more reliable insulation.

[0059] The double seaming structure 104a of the first modified example or the double seaming structure 104b of the second modified example can achieve the same effects as those of the above-described embodiment. For example, even if only the first folded portion 113 or the second folded portion 123 is used, the body hook 171 can be prevented from coming loose to a certain extent. In other words, the pressure resistance of the double seaming structure is improved. In particular, when insulation is not required, configurations such as the first modified example or the second modified example are effective when improving pressure resistance. Note that when insulation is not required, neither the second insulating layer 141 nor the first insulating layer 131 is necessary.

[0060] <Third Variation> 11E is an end view showing a schematic diagram of a double seaming structure according to a third modified example. In the third modified example, a first folded portion 113 is formed on the first metal member 111, and a second folded portion 223 is formed on the second metal member 121. In this modified example, as shown in FIG. 11E, the first folded portion 113 is bent so that the first end surface 114 of the first metal member 111 is positioned closer to the body wall 172 than the body hook 171. Furthermore, as shown in FIG. 11E, the second folded portion 223 is bent so that the second end surface 124 of the second metal member 121 is positioned closer to the body wall 172 than the cover hook 173. The double seaming structure 104c of this modified example also provides the same effects as those of the above-described embodiment. Since the first end face 114 and the second end face 124 are not opposed to each other and sandwich the second metal member 121 therebetween, it is easy to ensure insulation between the first end face 114 and the second end face 124. In this case, it is not necessary to form an insulating layer on the first end face 114 and the second end face 124.

[0061] <Fourth Variation> 11F is an end view showing a schematic diagram of a double seaming structure according to a fourth modified example. In the fourth modified example, a first folded portion 213 is formed on the first metal member 111, and a second folded portion 123 is formed on the second metal member 121. In this modified example, the first folded portion 213 is bent so that the first end surface 114 of the first metal member 111 is positioned closer to the seaming wall 174 than the body hook 171, as shown in FIG. 11F. Furthermore, the second folded portion 123 is bent so that the second end surface 124 of the second metal member 121 is positioned closer to the body hook 171 than the cover hook 173, as shown in FIG. 11F. The double seaming structure 104d of this modified example also provides the same effects as those of the above-described embodiment. Since the first end face 114 and the second end face 124 are not opposed to each other and sandwich the first metal member 111 therebetween, it is easy to ensure insulation between the first end face 114 and the second end face 124. In this case, it is not necessary to form an insulating layer on the first end face 114 and the second end face 124.

[0062] Fifth Variation 11G is an end view showing a schematic diagram of a double seaming structure 104e according to a fifth modified example. In the fifth modified example, the first metal member 111 is processed so as to be thinner at the first folded portion 113 of the first end portion 112 than at other portions. That is, the first folded portion 113 of this modified example includes a first thin-walled portion 116 where the thickness of the first metal member 111 is thinner than at other portions.

[0063] In the illustrated example, a first thin portion 116, which is obtained by reducing the thickness of the first metal member 111 by approximately half, is provided across the entire first folded portion 113. Therefore, the thickness of the first folded portion 113 formed by folding the first metal member 111 is equal to the thickness of the portion excluding the first folded portion 113. In other words, the first end portion 112, including the first folded portion 113, has a constant thickness.

[0064] FIG. 11H is a diagram illustrating an example of a method for forming the first folded portion 113 according to this modified example. In the processing method shown in FIG. 11H, a known processing method for reducing the thickness of a metal member, such as cutting using a rotary blade, pressing, or rolling, is appropriately used to thin the end of the first metal member 111 by a desired amount, thereby forming the first thin-walled portion 116. The length L of the first thin-walled portion 116, i.e., the length from the start of the first thin-walled portion 116 at the end of the first metal member 111 to the end of the first thin-walled portion 116, is, but is not limited to, 1 to 2 mm (FIG. 11H(a)). Next, the first thin-walled portion is folded back 180° so as to fold the thin-walled portion inward, thereby forming the first folded portion 113 (FIG. 11H(b)). Here, pressing is preferable for thinning the end portion because it does not produce cutting chips. In the illustrated example, the insulating layer 131 is formed before the folded portion 113 is formed, but the insulating layer 131 may be formed after the folded portion 113 is formed.

[0065] 11G, the explanation will be continued. In this modification, the second folded portion 123 of the second end portion 122 has a configuration similar to the first folded portion 113 of the first end portion 112. In the second folded portion 123 of the second end portion 122, the second metal member 121 is processed to be thinner than other portions. That is, the second folded portion 123 of this modification includes a second thin portion 126 where the thickness of the second metal member 121 is thinner than other portions.

[0066] In the illustrated example, second thin-walled portion 126, which is obtained by reducing the thickness of second metal member 121 by approximately half, is provided over the entire area of ​​second folded portion 123, and the thickness of second folded portion 123 formed by folding second metal member 121 is equal to the thickness of the portion excluding second folded portion 123. In other words, second end portion 122, including second folded portion 123, has a constant thickness. The second folded portion 123 of this modified example can be formed by the same processing method as that for the first folded portion 113.

[0067] Even with the first folded portion 113 and the second folded portion 123 of this modified example, the tip portion of the first end 112 of the first metal member 111 and the tip portion of the second end 122 of the second metal member 121 are rounded, so that the second insulating layer 141 and the first insulating layer 131 are not destroyed during seaming.

[0068] Furthermore, according to this modification, it is possible to provide a double seaming structure 104e that is thinner than the first embodiment and the like.

[0069] The first folded portion 113 may be processed to be thinner than the other portions of the first metal member 111, and the thickness of the first thin-walled portion 116 may be thicker than approximately half the thickness of the first metal member 111. In this case, the thickness is reduced compared to the first embodiment, and since the first folded portion 113 bulges at the first end 112, this bulge provides resistance, making it somewhat difficult for the body hook 171 to come off. In other words, the pressure resistance of the double seaming structure is improved. The same applies when the second thin-walled portion 126 of the second folded portion 123 is thicker than approximately half the thickness of the second metal member 121.

[0070] When the thickness of the first thin-walled portion 116 of the first folded portion 113 is formed to be thicker than approximately half the thickness of the first metal member 111, the thickness of the second thin-walled portion 126 of the second folded portion 123 is formed to be thicker than approximately half the thickness of the second metal member 121, and the first end face 114 of the first metal member 111 and the second end face 124 of the second metal member 121 face each other in a double seaming structure as in the folding direction shown in the first embodiment, the body hook 171 is less likely to come off. This is because the first end face 114 and the second end face 124 provide resistance to deformation that would cause the body hook 171 to come off, although not as much as in the first embodiment.

[0071] 11G, the first folded portion 113 is formed by folding the first metal member 111 so that the first end surface 114 of the first metal member 111 is positioned on the body wall 172 side of the body hook 171, and the second folded portion 123 is formed by folding the second metal member 121 so that the second end surface 124 of the second metal member 121 is positioned on the seaming wall 174 side of the cover hook 173. However, this is not limited to this. The folding directions of the first folded portion 113 and the second folded portion 123 may be in either direction. In the first folded portion 113, the first metal member 111 may be folded so that the first end surface 114 is positioned on the seaming wall 174 side of the body hook 171. At the second folded portion 123, the second metal member 121 may be folded so that the second end surface 124 is positioned on the chuck wall 175 side of the cover hook 173. That is, the folding direction may be any of those shown in the first embodiment, the second embodiment, the third modified example, and the fourth modified example.

[0072] Furthermore, in the fifth modified example, as in the first and second modified examples described above, insulation may be achieved by only either the first insulating layer 131 or the second insulating layer 141. In that case, an insulating layer may be formed on one of the first metal member 111 and the second metal member 121, and the folded portion of this modified example may be provided only on the other metal member on which no insulating layer is formed. If insulation is not required, neither the first insulating layer 131 nor the second insulating layer 141 is necessary.

[0073] The present invention has been described above by showing preferred embodiments, but it goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.

[0074] For example, although it is one preferred embodiment that an anaerobic adhesive 151 is used, other types of adhesives may be used, or no adhesive may be used at all.

[0075] The double seam structure according to the above-described embodiment and modified example may be used for other containers other than battery containers, such as cans for beverages, food, etc. In this case, an insulating layer may not be provided. The double seam structure according to the above-described embodiment and modified example provides high sealing properties and pressure resistance to cans and the like. [Explanation of symbols]

[0076] 1...Battery 2...Battery container 3...Can body 31... bottom surface portion, 32... cylindrical portion, 38... flange portion 4...Can lid 41...flat portion, 42...joint portion, 48...curl portion 5...Tie-down section 9...Battery section 100...Double seaming structure 111...first metal member, 112...first end portion, 113...first folded portion 114...first end face, 115...first region, 116...first thin-walled portion 121... second metal member, 122... second end portion, 123... second folded portion 124... second end surface, 125... second region, 126... second thin-walled portion 131...first insulating layer, 141...second insulating layer 151...Adhesive 171...Body hook, 172...Body wall 173...Cover hook, 174...Seaming wall, 175...Chuck wall

Claims

1. a first metal member having a first folded portion at a first end; a second metal member; Equipped with a first region including the first end of the first metal member and a second region including the second end of the second metal member are tightly contacted by double seaming to maintain a sealed state; A double seaming structure, the first folded portion includes a first thin-walled portion in which the thickness of the first metal member is thinner than other portions, the first thin-walled portion is provided over the entire area of ​​the first folded-back portion, The first end portion, including the first folded portion, has a constant thickness. Double-sealed structure.

2. a first metal member having a first folded portion at a first end; a second metal member; Equipped with a first region including the first end of the first metal member and a second region including the second end of the second metal member are tightly contacted by double seaming to maintain a sealed state; A double seaming structure, the second metal member has a second folded portion at the second end, the second folded portion includes a second thin-walled portion in which the thickness of the second metal member is thinner than other portions, the second thin portion is provided over the entire area of ​​the second folded portion, The second end portion, including the second folded portion, has a constant thickness. Double-sealed structure.

3. The first end surface of the first metal member and the second end surface of the second metal member sandwich at least one of the first metal member and the second metal member therebetween, and are not opposed to each other in the double seaming structure. The double seaming structure according to claim 2.

4. a first metal member having a first folded portion at a first end; a second metal member; Equipped with a first region including the first end of the first metal member and a second region including the second end of the second metal member are tightly sealed by double seaming, and The first metal member in the first region has a body wall extending in a first direction and a body hook that is folded back outward from an end in the first direction to extend in a second direction opposite to the first direction and has the first folded back portion, The second metal member in the second region has a cover hook provided so as to enter between the body hook and the body wall from a second direction, a seaming wall folded back outward from a second direction end of the cover hook and extending in a first direction outside the body hook, and a chuck wall folded back inward from a first direction end of the seaming wall and extending in the second direction inside the body wall. A double seaming structure, the second metal member has a second folded portion at the second end, The first end surface of the first metal member and the second end surface of the second metal member sandwich at least one of the first metal member and the second metal member therebetween, and are not opposed to each other in the double seaming structure. Double-sealed structure.

5. The double seaming structure according to any one of claims 1 to 4, further comprising an insulating layer that electrically insulates the first region from the second region.

6. The double seaming structure according to claim 5 , wherein the insulating layer is a coating film formed on at least the second region.

7. The double seaming structure according to any one of claims 1 to 6, further comprising an adhesive solidified at the contact portion between the first region and the second region.

8. The double seaming structure according to claim 7, wherein the adhesive is an anaerobic adhesive.

9. The double seaming structure according to any one of claims 1 to 8, a positive electrode material and a negative electrode material accommodated in a space sealed by the first metal member and the second metal member; Equipped with one of the positive electrode material and the negative electrode material is connected to the first metal member; the other of the positive electrode material and the negative electrode material is connected to the second metal member; battery.

10. A first metal member having a first folded portion at a first end; a second metal member; Equipped with a first region including the first end of the first metal member and a second region including the second end of the second metal member are tightly contacted by double seaming to maintain a sealed state; A double seaming structure, the first folded portion includes a first thin portion in which the thickness of the first metal member is thinner than other portions; Double seaming structure, a positive electrode material and a negative electrode material accommodated in a space sealed by the first metal member and the second metal member; Equipped with one of the positive electrode material and the negative electrode material is connected to the first metal member; the other of the positive electrode material and the negative electrode material is connected to the second metal member; battery.

11. A first metal member having a first folded portion at a first end; a second metal member; Equipped with a first region including the first end of the first metal member and a second region including the second end of the second metal member are tightly contacted by double seaming to maintain a sealed state; A double seaming structure, the second metal member has a second folded portion at the second end, The first end surface of the first metal member and the second end surface of the second metal member sandwich at least one of the first metal member and the second metal member therebetween, and are not opposed to each other in the double seaming structure. Double seaming structure, a positive electrode material and a negative electrode material accommodated in a space sealed by the first metal member and the second metal member; Equipped with one of the positive electrode material and the negative electrode material is connected to the first metal member; the other of the positive electrode material and the negative electrode material is connected to the second metal member; battery.

12. A first metal member having a first folded portion at a first end; a second metal member; Equipped with a first region including the first end of the first metal member and a second region including the second end of the second metal member are tightly contacted by double seaming to maintain a sealed state; A double seaming structure, the second metal member has a second folded portion at the second end, A first end surface of the first metal member and a second end surface of the second metal member face each other in the double seaming structure. Double seaming structure, a positive electrode material and a negative electrode material accommodated in a space sealed by the first metal member and the second metal member; Equipped with one of the positive electrode material and the negative electrode material is connected to the first metal member; the other of the positive electrode material and the negative electrode material is connected to the second metal member; battery.

13. The double seaming structure according to any one of claims 1 to 4, a can body formed from one of the first metal member and the second metal member; a can lid formed from the other of the first metal member and the second metal member; Canned food.

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