Battery and method for manufacturing battery

Abstract

Provided is a battery having: a charge / discharge body containing an electrolyte; a storage body (lid 420) including a liquid injection hole (420c); and a sealing plug (440) inserted into the liquid injection hole (420c). The liquid injection hole (420c) of the lid (420) includes a first penetration section (420P) and a second penetration section (420Q). The first penetration section (420P) includes a first inner peripheral surface (423) and an opposing surface (425). The second penetration section (420Q) includes a second inner peripheral surface (427). The sealing plug (440) includes a first insertion section (440P) and a second insertion section (440Q). The first insertion section (440P) includes a first outer peripheral surface (443) and an opposed surface (445). The second insertion section (440Q) includes a second outer peripheral surface (447). The length (L1) of a space (S1) between the second inner peripheral surface (427) of the lid (420) and the second outer peripheral surface (447) of the sealing plug (440) is at least partially greater than the length (L2) of a space (S2) between the first inner peripheral surface (423) of the lid (420) and the first outer peripheral surface (443) of the sealing plug (440).

Description

Battery and battery manufacturing method

[0001] The present invention relates to a battery and a method for manufacturing the battery.

[0002] 2. Description of the Related Art Batteries provided with a sealing plug that seals a liquid inlet have been known (see, for example, Patent Document 1).

[0003] Patent No. 4110632

[0004] There is a need for sufficient attachment and bonding of the battery seal and the container.

[0005] The battery of the present invention includes a charging / discharging unit containing an electrolyte, a housing that houses the charging / discharging unit and includes a filler hole for introducing the electrolyte, and a sealing stopper that is inserted into the filler hole and is stacked and joined to the housing. The filler hole of the housing includes a first penetration portion that penetrates along the stacking direction with the sealing stopper and faces the outside of the housing, and a second penetration portion that penetrates along the stacking direction, faces the inside of the housing, is connected to the first penetration portion along the stacking direction, and has a smaller opening than the first penetration portion. The first penetration portion includes a first inner circumferential surface that is aligned with the stacking direction and an opposing surface that intersects with and is adjacent to the first inner circumferential surface and faces opposite the stacking direction. The second penetration portion includes a second inner circumferential surface that intersects with and is adjacent to the opposing surface, is located inside the housing relative to the first inner circumferential surface, and is aligned with the stacking direction. The sealing plug includes a first insertion portion inserted into the first through-portion along the stacking direction, and a second insertion portion inserted into the second through-portion along the stacking direction, connected to the first insertion portion along the stacking direction, and having a smaller area facing in the stacking direction than the first insertion portion. The first insertion portion includes a first outer peripheral surface facing the first inner peripheral surface of the container, and an opposed surface that intersects with and is adjacent to the first outer peripheral surface and faces the opposed surface of the container. The second insertion portion includes a second outer peripheral surface that intersects with and is adjacent to the opposed surface, is located more inward of the container than the first outer peripheral surface, and faces the second inner peripheral surface of the container. A length of a gap between the second inner peripheral surface of the container and the second outer peripheral surface of the sealing plug is at least partially wider than a length of a gap between the first inner peripheral surface of the container and the first outer peripheral surface of the sealing plug.

[0006] The method for manufacturing a battery of the present invention includes a first step of attaching the container and the sealing plug by bringing the container and the sealing plug closer together along the stacking direction while the opposing surface of the container and the opposed surface of the sealing plug are opposed to each other in the stacking direction, and a second step of welding the container and the sealing plug together after the first step.

[0007] According to the present invention, the battery sealing plug and the container can be satisfactorily attached and joined.

[0008] 1. A perspective view showing a battery 1 according to an embodiment. A side view showing, in cross section, components around a positive terminal 310 of the battery 1 in region 2A-2B of FIG. 1. A side view showing, in cross section, components around a negative terminal 320 of the battery 1 in region 3A-3B of FIG. 1. A perspective view showing a partially exploded battery 1. A perspective view showing the charging / discharging body 100 of FIG. 4. A side view showing, in cross section, a portion of the charging / discharging body 100 in region 6A-6B of FIG. 5. A perspective view showing, in exploded form, components around a positive terminal 310 of the battery 1. A perspective view showing, in exploded form, components around a split valve 430 and a sealing plug 440 of the battery 1. An end view showing, in exploded form, main parts of an exterior body 400 according to an embodiment. A perspective view showing, in exploded form, components around a negative terminal 320 of the battery 1. An end view showing main parts of an exterior body 400 according to an embodiment. 10 is an end view showing the attachment and joining of a sealing stopper 440 and a lid 420 in relation to a manufacturing method of a battery 1 of an embodiment. An end view showing a main portion of an exterior body 400A of a first modified embodiment. An end view showing a main portion of an exterior body 400B of a second modified embodiment. An end view showing a main portion of an exterior body 400C of a third modified embodiment. An end view showing a main portion of an exterior body 400D of a fourth modified embodiment. An end view showing a main portion of an exterior body 400E of a fifth modified embodiment. An end view showing a main portion of an exterior body 400F of a sixth modified embodiment. An end view showing a main portion of an exterior body 400G of a seventh modified embodiment. An end view showing the attachment and joining of a sealing stopper 770 and a lid 420 in relation to a manufacturing method of a battery 1 of a seventh modified embodiment. An end view showing a main portion of an exterior body 400H of an eighth modified embodiment. 10 is an end view showing a main part of an exterior body 400J configured in a best mode including the configurations of the embodiment and modified examples 1 to 8 of the embodiment. FIG. 11 is an end view showing a main part of an exterior body 400K in which a sealing plug 820 and a lid 420 are eccentric and which can be applied to the configurations of the embodiment and modified examples 1 to 8 of the embodiment.

[0009] Embodiments of the present invention will be described with reference to the drawings. To facilitate understanding of each embodiment, the size and proportions of components may be exaggerated in each drawing. The same reference numerals are used for the same components in each drawing. In each drawing, the longitudinal direction X, lateral direction Y, and height direction Z of the battery 1 are indicated by arrows. In each drawing, the longitudinal direction X, lateral direction Y, and height direction Z of the battery 1 indicate the relative positional relationship within the same drawing. That is, if the battery 1 is rotated 180 degrees and placed with the top and bottom sides reversed, or if the battery 1 is rotated 90 degrees and placed with the top side facing sideways, the longitudinal direction X, lateral direction Y, and height direction Z of the battery 1 will change. In each drawing, the stacking direction V of the sealing plug 440, etc. and the lid 420, etc. is indicated by an arrow. The stacking direction V of the sealing plug 440, etc. and the lid 420, etc. corresponds to the height direction Z of the battery 1.

[0010] (Configuration of Battery 1 of the Embodiment) The configuration of the battery 1 will be described with reference to FIGS. 1 to 11. FIG.

[0011] FIG. 1 is a perspective view showing a battery 1 according to an embodiment. FIG. 2 is a side view showing a cross section of components around the positive terminal 310 of the battery 1 in region 2A-2B of FIG. 1 . FIG. 3 is a side view showing a cross section of components around the negative terminal 320 of the battery 1 in region 3A-3B of FIG. 1 . FIG. 4 is a perspective view showing a partially exploded battery 1. FIG. 5 is a perspective view showing the charging / discharging body 100 of FIG. 4 . FIG. 6 is a side view showing a cross section of a portion of the charging / discharging body 100 in region 6A-6B of FIG. 5 . FIG. 7 is a perspective view showing an exploded view of components around the positive terminal 310 of the battery 1. FIG. 8 is a perspective view showing an exploded view of components around the split valve 430 and sealing plug 440 of the battery 1. FIG. 9 is an end view showing an exploded view of the main parts of the exterior body 400 according to an embodiment. FIG. 10 is a perspective view showing an exploded view of components around the negative terminal 320 of the battery 1. FIG. 11 is an end view showing a main part of the exterior body 400 of the embodiment.

[0012] Battery 1 includes a charging / discharging body 100 that charges and discharges electricity, a current collector 200 connected to charging / discharging body 100, an electrode terminal 300 connected to current collector 200, an outer casing 400 in which the components of battery 1 are housed or attached, an insulator 500 that insulates the components of battery 1 from the outer casing 400, and a sealing body 600 that seals the components of battery 1 from the outer casing 400.

[0013] The charge / discharge unit 100 charges and discharges electricity. The charge / discharge unit 100 shown in Figures 2 to 6 includes a positive electrode 110, a negative electrode 120, a separator 130, and an electrolyte 140. The charge / discharge unit 100 is configured by winding components, in which the positive electrode 110, the separator 130, the negative electrode 120, and the separator 130 are stacked in this order, into a rectangular parallelepiped shape. The charge / discharge unit 100 may be configured by winding or stacking.

[0014] The positive electrode 110 includes a long positive electrode current collecting layer 111 and positive electrode active material layers 112 bonded to both sides of the positive electrode current collecting layer 111. As shown in FIG. 5 , the positive electrode 110 is wound together with the negative electrode 120 and the separator 130 to form a rectangular parallelepiped with convexly curved ends. One side 111a of the positive electrode current collecting layer 111 is not covered by the separator 130 and is exposed to the outside. The positive electrode active material layer 112 is not bonded to the side 111a. As shown in FIG. 4 , the central portion of the side 111a is compressed in the short-side direction Y of the battery 1 when bundled. The side 111a is bonded to the positive electrode current collecting layer 111. The positive electrode active material layer 112 is bonded to the positive electrode current collecting layer 111 except for the side 111a. The positive electrode active material layer 112 is bonded to both sides of the positive electrode current collecting layer 111. The positive electrode 110 may be configured such that the positive electrode active material layer 112 is bonded to only one side of the positive electrode current collecting layer 111. The positive electrode current collecting layer 111 is formed of, for example, aluminum or an aluminum alloy. The positive electrode active material layer 112 contains a positive electrode active material formed of a lithium-containing composite oxide, a binder, a conductive additive, and the like. The lithium-containing composite oxide contains, for example, a metal element such as nickel (Ni), cobalt (Co), or manganese (Mn), and lithium (Li).

[0015] The negative electrode 120 includes a long negative electrode current collecting layer 121 and negative electrode active material layers 122 bonded to both sides of the negative electrode current collecting layer 121. As shown in FIG. 5 , the negative electrode 120 is wound together with the positive electrode 110 and the separator 130 to form a rectangular parallelepiped with convexly curved ends. One side 121a of the negative electrode current collecting layer 121 is not covered by the separator 130 and is exposed to the outside. The negative electrode active material layer 122 is not bonded to the side 121a. As shown in FIG. 4 , the central portion of the side 121a is compressed in the short-side direction Y of the battery 1 when bundled. As shown in FIG. 5 , the side 121a of the negative electrode current collecting layer 121 faces the side 111a of the positive electrode current collecting layer 111 along the longitudinal direction X of the battery 1. The side portion 121a is bonded to the negative electrode current collector plate 220. The negative electrode active material layer 122 is bonded to the negative electrode current collector layer 121 except for the side portion 121a. The negative electrode active material layer 122 is bonded to both sides of the negative electrode current collector layer 121. The negative electrode 120 may be configured such that the negative electrode active material layer 122 is bonded to only one side of the negative electrode current collector layer 121. The negative electrode current collector layer 121 is formed of, for example, copper or a copper alloy. The negative electrode active material layer 122 contains a negative electrode active material made of a carbon-based material, a binder, a conductive additive, and the like. The carbon-based material may be, for example, graphite.

[0016] The separator 130 allows lithium ions to pass through while insulating the positive electrode 110 and the negative electrode 120. The separator 130 is formed in a long shape. The separator 130 is made of a porous material. Polyethylene (PE) or polypropylene (PP) is used for the separator 130. An insulating member may be used instead of the separator 130. The insulating member may be provided on the side of the positive electrode 110 facing the negative electrode 120. The insulating member may be provided on the side of the negative electrode 120 facing the positive electrode 110. The insulating member may be heat-resistant. In such a configuration, the separator 130 is not essential.

[0017] The electrolyte 140 allows lithium ions to circulate between the positive electrode 110 and the negative electrode 120. The electrolyte 140 is also called an electrolytic solution. The electrolyte 140 contains a solvent and a solute. The electrolyte 140 may contain an additive. The solvent contains, for example, an organic solvent. The organic solvent is, for example, a carbonate ester such as ethylene carbonate. The solute contains, for example, a lithium salt. The lithium salt is, for example, lithium hexafluorophosphate (LiPF ６ ) is used.

[0018] The current collector 200 is connected to the charge / discharge element 100. The current collector 200 is also called a current collector plate. The current collector 200 shown in Figures 2 to 4, 7, and 10 includes a positive electrode current collector plate 210 and a negative electrode current collector plate 220.

[0019] As shown in FIG. 4 , the positive current collector plate 210 electrically connects the positive electrode 110 and the positive electrode terminal 310. As shown in FIG. 7 , the positive current collector plate 210 includes a base 211 and a current collector 212. As shown in FIG. 2 , the base 211 is joined to a joint 313 of the positive electrode terminal 310. The base 211 is joined to the joint 313, for example, by crimping the joint 313. As shown in FIG. 7 , the base 211 is formed in a plate shape. A circular insertion hole 211a is formed in the base 211. As shown in FIG. 2 , the joint 313 of the positive electrode terminal 310 is inserted into the insertion hole 211a of the base 211. The current collector 212 is joined to the side portion 111a of the positive electrode 110 by, for example, ultrasonic welding or laser welding. As shown in Fig. 7 , the current collecting portion 212 is formed by bending from the outer edge of the base portion 211 downward in the height direction Z. The current collecting portion 212 extends perpendicular to the base portion 211. The current collecting portion 212 is formed integrally with the base portion 211. The current collecting portion 212 is bent in the short-side direction Y along the outer shape of the side portion 111a of the positive electrode 110. The positive electrode current collecting plate 210 is formed of, for example, aluminum or an aluminum alloy.

[0020] As shown in FIG. 4 , the negative current collector 220 electrically connects the negative electrode 120 and the negative terminal 320. The external shape of the negative current collector 220 is symmetrical to the external shape of the positive current collector 210 along the longitudinal direction X. As shown in FIG. 10 , the negative current collector 220 includes a base 221 and a current collector 222. As shown in FIG. 3 , the base 221 is joined to a joint 323 of the negative terminal 320. The base 221 is joined to the joint 323 by, for example, crimping the joint 323. As shown in FIG. 10 , the base 221 is formed in a plate shape. A circular insertion hole 221a is formed in the base 221. As shown in FIG. 3 , the joint 323 of the negative terminal 320 is inserted into the insertion hole 221a of the base 221. The current collecting portion 222 is joined to the side portion 121 a of the negative electrode 120 by, for example, ultrasonic bonding or laser welding. As shown in FIG. 10 , the current collecting portion 222 is formed by bending from the outer edge of the base portion 221 downward in the height direction Z. The current collecting portion 222 extends perpendicular to the base portion 221. The current collecting portion 222 is formed integrally with the base portion 221. The current collecting portion 222 is bent in the short direction Y to follow the outer shape of the side portion 121 a of the negative electrode 120. The negative electrode current collecting plate 220 is formed of, for example, copper or a copper alloy.

[0021] The electrode terminal 300 is connected to the current collector 200. The electrode terminal 300 shown in Figures 1 to 4, 7 and 10 includes a positive electrode terminal 310 and a negative electrode terminal 320.

[0022] As shown in FIG. 4 , the positive terminal 310 is connected to the positive current collector plate 210. As shown in FIG. 7 , the positive terminal 310 includes a rectangular parallelepiped base 311, a cylindrical insertion portion 312 that protrudes downward in FIG. 7 from the base 311, and a cylindrical joint portion 313 that protrudes downward in FIG. 7 from the outer periphery of the insertion portion 312. As shown in FIG. 2 , the positive terminal 310 also includes a sealing portion 314 that is formed in an annular shape at the inner boundary between the base 311 and the insertion portion 312. The base 311 is provided in the base 611 of the positive side gasket 610. The insertion portion 312 is inserted into the positive side gasket 610 as shown in FIG. 2 . The joint portion 313 protrudes downward in FIG. 2 from an insertion hole 211 a in the base 211 of the positive current collector plate 210 as shown in FIG. 2 . The protruding portion of the joint portion 313 is expanded radially outward and joined to the base 211. The joint portion 313 is crimped to the base 211. Furthermore, the joint portion 313 is welded to the base 211. The sealing portion 314 is a convex portion that protrudes toward the positive electrode side gasket 610. As shown in FIG. 2 , the sealing portion 314 of the positive electrode terminal 310, together with the lid 420, partially compresses the base 611 of the positive electrode side gasket 610 along the height direction Z. This seals the positive electrode terminal 310 and the lid 420 via the positive electrode side gasket 610. The positive electrode terminal 310 is formed of, for example, aluminum or an aluminum alloy.

[0023] As shown in FIG. 4 , the negative electrode terminal 320 is connected to the negative electrode current collector plate 220. The external shape of the negative electrode terminal 320 is the same as that of the positive electrode terminal 310. As shown in FIG. 10 , the negative electrode terminal 320 includes a rectangular parallelepiped plate-shaped base 321, a cylindrical insertion portion 322 that protrudes downward from the base 321 in FIG. 10 , and a cylindrical joint portion 323 that protrudes downward from the outer periphery of the insertion portion 322 in FIG. 10 . Furthermore, as shown in FIG. 3 , the negative electrode terminal 320 includes a sealing portion 324 that is formed in an annular shape at the inner boundary between the base 321 and the insertion portion 322. The base 321 is provided on the base 621 of the negative electrode side gasket 620. The insertion portion 322 is inserted into the negative electrode side gasket 620 as shown in FIG. 3 . As shown in FIG. 3 , the joint portion 323 protrudes downward in FIG. 3 from the insertion hole 221 a of the base 221 of the negative current collector plate 220. The protruding portion of the joint portion 323 is expanded radially outward and joined to the base 221. The joint portion 323 is crimped to the base 221. Furthermore, the joint portion 323 is welded to the base 221. The sealing portion 324 is a convex portion protruding toward the negative electrode side gasket 620. As shown in FIG. 3 , the sealing portion 324 of the negative electrode terminal 320, together with the lid 420, partially compresses the base 621 of the negative electrode side gasket 620 along the height direction Z. This seals the negative electrode terminal 320 and the lid 420 via the negative electrode side gasket 620. The negative electrode terminal 320 is formed of, for example, copper or a copper alloy.

[0024] The components of the battery 1 are housed or attached in the exterior body 400. The exterior body 400 shown in Figures 1 to 4 and 7 to 11 includes a container 410, a lid 420, a split valve 430, and a sealing plug 440.

[0025] The container 410 contains the charge / discharge unit 100 and the like. The container 410 is a container. The container 410 is made of a rectangular parallelepiped metal can. The container 410 includes an opening 410a that opens along the longitudinal direction and a container portion 410b that is continuous with the opening 410a. The container 410 is made of, for example, aluminum or an aluminum alloy.

[0026] (Lid 420 of the embodiment) The lid 420 accommodates the charge / discharge unit 100 together with the container 410. The lid 420 is a container. The lid 420 seals the opening 410a of the container 410. The container 410 is formed of a long, plate-shaped metal plate. As shown in FIG. 7 , the lid 420 has a positive electrode side insertion hole 420a formed as a circular through-hole at one end in the longitudinal direction X. The insertion portion 312 of the positive electrode terminal 310 and the insertion portion 612 of the positive electrode side gasket 610 are inserted into the positive electrode side insertion hole 420a. As shown in FIG. 10 , the lid 420 has a negative electrode side insertion hole 420b formed as a circular through-hole at the other end in the longitudinal direction X. The insertion portion 322 of the negative electrode terminal 320 and the insertion portion 622 of the negative electrode side gasket 620 are inserted into the negative electrode side insertion hole 420b. 8, the lid 420 includes an injection hole 420c for inserting the electrolyte 140 between the positive electrode side insertion hole 420a and the negative electrode side insertion hole 420b. The lid 420 is welded to the container 410. The lid 420 is made of, for example, aluminum or an aluminum alloy.

[0027] 11, a sealing plug 440 is inserted into the liquid inlet 420c of the lid 420. As shown in FIGS. 8, 9, and 11, the liquid inlet 420c includes a first through portion 420P and a second through portion 420Q.

[0028] As shown in Figures 8, 9, and 11, the first penetrating portion 420P penetrates along the stacking direction V with the sealing plug 440 and faces the outside of the lid 420. The outside of the lid 420 is the side away from the charge / discharge body 100. As shown in Figure 9, the first penetrating portion 420P includes an outer surface 421, an end portion 422, a first inner circumferential surface 423, an end portion 424, and an opposing surface 425. The outer surface 421, the end portion 422, the first inner circumferential surface 423, the end portion 424, and the opposing surface 425 are connected in that order to form the outer shape of the first penetrating portion 420P.

[0029] As shown in FIG. 9 , the outer surface 421 of the first penetration portion 420P is located outside the battery 1. As shown in FIG. 9 , the end 422 is the boundary between the outer surface 421 and the first inner circumferential surface 423. As an example, the end 422 is formed in a circular shape. As shown in FIGS. 9 and 11 , the first inner circumferential surface 423 is adjacent to and intersects with the outer surface 421 and is formed along the stacking direction V. As an example, the first inner circumferential surface 423 is perpendicular to the outer surface 421. The first inner circumferential surface 423 is located inside the lid 420 relative to the outer surface 421. The inside of the lid 420 is the side of the inner surface 429 of the lid 420, which corresponds to the inside of the battery 1. As an example, the first inner circumferential surface 423 is formed in an annular shape when viewed from the stacking direction V. As shown in FIGS. 9 and 11 , the end 424 is the boundary between the first inner circumferential surface 423 and the opposing surface 425. The end portion 424 is the lower end of the first inner circumferential surface 423 and the outer edge of the opposing surface 425. The end portion 424 is formed in a circular shape, for example.

[0030] As shown in FIGS. 9 and 11 , the opposing surface 425 of the first penetrating portion 420P intersects with and is adjacent to the first inner circumferential surface 423 and faces the stacking direction V. As an example, the opposing surface 425 is perpendicular to the first inner circumferential surface 423. As an example, the opposing surface 425 is formed in an annular shape. That is, the opposing surface 425 includes an outer edge and an inner edge. The outer edge of the opposing surface 425 corresponds to the end portion 424. The inner edge of the opposing surface 425 corresponds to the second end portion 426 of the second penetrating portion 420Q.

[0031] As shown in FIGS. 8, 9, and 11, the second through portion 420Q penetrates along the stacking direction V with the sealing plug 440 and faces the inside of the lid 420. The inside of the lid 420 is the side closer to the charge / discharge body 100. The second through portion 420Q is connected to the first through portion 420P along the stacking direction V. The central axis of the second through portion 420Q coincides with the central axis of the first through portion 420P. The second through portion 420Q is molded integrally with the first through portion 420P. The second through portion 420Q has a smaller opening than the first through portion 420P. The opening is an opening in a plane defined by the short direction Y and the long direction X. The second through portion 420Q includes a second end portion 426, a second inner circumferential surface 427, an end portion 428, and an inner surface 429. The second end 426, the second inner circumferential surface 427, the end 428, and the inner surface 429 are connected in that order to form the outer shape of the second penetrating portion 420Q. The second end 426 is connected to the opposing surface 425 of the first penetrating portion 420P.

[0032] As shown in FIGS. 9 and 11 , the second end 426 of the second through portion 420Q is a boundary between the opposing surface 425 and the second inner circumferential surface 427. For example, the second end 426 is formed in a circular shape. As shown in FIGS. 9 and 11 , the second inner circumferential surface 427 is adjacent to and intersects with the opposing surface 425 and is formed along the stacking direction V. For example, the second inner circumferential surface 427 is perpendicular to the opposing surface 425. The second inner circumferential surface 427 is located more inward of the lid 420 than the first inner circumferential surface 423. For example, the second inner circumferential surface 427 is formed in an annular shape when viewed from the stacking direction V. The central axis of the second inner circumferential surface 427 coincides with the central axis of the first inner circumferential surface 423. As shown in FIG. 9 , the end 428 is a boundary between the second inner circumferential surface 427 and the inner surface 429. The end 428 is the lower end of the second inner circumferential surface 427. The end portion 428 is formed in a circular shape, for example. The inner surface 429 is located inside the battery 1, as shown in FIG.

[0033] As shown in FIG. 8 , the split valve 430 is provided on the lid 420. When the internal pressure of the battery 1 reaches a predetermined value, the split valve 430 splits outward from the battery 1, thereby releasing the internal pressure of the battery 1 to atmospheric pressure. The split valve 430 is formed, for example, in an elliptical shape. The split valve 430 is formed to be thinner than the lid 420. The split valve 430 is formed with a groove that serves as a reference for splitting. The split valve 430 is formed integrally with the lid 420. The split valve 430 may be formed separately from the lid 420 and then welded in an annular shape to a through-hole provided in the lid 420.

[0034] (Sealing plug 440 of embodiment) The sealing plug 440 is inserted into the liquid injection hole 420c of the lid 420 shown in Fig. 8. The sealing plug 440 is laminated and joined to the lid 420 as shown in Fig. 1. The sealing plug 440 includes a first insertion portion 440P and a second insertion portion 440Q as shown in Figs. 8, 9 and 11. The first insertion portion 440P of the sealing plug 440 is welded to the lid 420. The sealing plug 440 is formed of, for example, aluminum or an aluminum alloy.

[0035] 8, 9, and 11, the first insertion portion 440P is inserted into the first penetrating portion 420P along the stacking direction V. As shown in Fig. 9, the first insertion portion 440P includes an outer surface 441, an end portion 442, a first outer peripheral surface 443, an end portion 444, and an opposed surface 445. The outer surface 441, the end portion 442, the first outer peripheral surface 443, the end portion 444, and the opposed surface 445 are connected in that order to form the outer shape of the first insertion portion 440P.

[0036] As shown in Fig. 9 , the outer surface 441 of the first insertion portion 440P is located outside the battery 1. The outer surface 441 is formed in a circular shape, for example. The outer surface 441 is located outside the battery 1 relative to the outer surface 421 of the lid 420 in the stacking direction V. The outer surface 441 may be located adjacent to the outer surface 421 of the lid 420 in the stacking direction V. The outer surface 441 may be located inside the battery 1 relative to the outer surface 421 of the lid 420 in the stacking direction V.

[0037] The end 442 of the first insertion portion 440P is a boundary between the outer surface 441 and the first outer peripheral surface 443. The end 442 is the outer edge of the outer surface 441. The end 442 is formed in a circular shape, for example. As shown in FIGS. 9 and 11 , the first outer peripheral surface 443 is adjacent to and intersects with the outer surface 441 and is formed along the stacking direction V. For example, the first outer peripheral surface 443 is perpendicular to the outer surface 441. The first outer peripheral surface 443 is located more inward of the lid 420 than the outer surface 441. For example, the first outer peripheral surface 443 is formed in an annular shape when viewed from the stacking direction V. The first outer peripheral surface 443 faces the first inner peripheral surface 423 of the lid 420 along a direction intersecting the stacking direction V. The directions intersecting the stacking direction V are the short-side direction Y and the long-side direction X. 9 and 11 , the end 444 is the boundary between the first outer peripheral surface 443 and the opposed surface 445. The end 444 is the lower end of the first outer peripheral surface 443 and the outer edge of the opposed surface 445. The end 444 is formed in a circular shape, for example. The end 444 faces the end 424 of the lid 420 along a direction intersecting the stacking direction V.

[0038] As shown in FIGS. 9 and 11 , the opposed surface 445 of the first insertion portion 440P is adjacent to and intersects the first outer peripheral surface 443, and faces the stacking direction V. The opposed surface 445 faces the opposing surface 425 of the lid 420. As an example, the opposed surface 445 is perpendicular to the first outer peripheral surface 443. As an example, the opposed surface 445 is formed in an annular shape. That is, the opposed surface 445 includes an outer edge and an inner edge. The outer edge of the opposed surface 445 corresponds to the end 444. The inner edge of the opposed surface 445 corresponds to the first end 446 of the second insertion portion 440Q. The opposed surface 445 is in partial surface contact with the opposing surface 425 of the lid 420 in a region along a direction intersecting the stacking direction V from the first inner peripheral surface 423 of the lid 420 to the second outer peripheral surface 447 of the sealing plug 440. The opposed surface 445 is in surface contact with the opposing surface 425 of the lid 420 except for the vicinity of the first inner peripheral surface 423 of the lid 420 and the vicinity of the second outer peripheral surface 447 of the sealing plug 440 .

[0039] As shown in FIGS. 8, 9, and 11, the second insertion portion 440Q is inserted into the second penetrating portion 420Q along the stacking direction V. The second insertion portion 440Q is connected to the first insertion portion 440P along the stacking direction V. The central axis of the second insertion portion 440Q coincides with the central axis of the first insertion portion 440P. The area of ​​the second insertion portion 440Q facing the stacking direction V is smaller than that of the first insertion portion 440P. The area is the area on a plane defined by the short-side direction Y and the long-side direction X. The second insertion portion 440Q includes a first end portion 446, a second outer peripheral surface 447, an end portion 448, and an inner surface 449. The first end portion 446, the second outer peripheral surface 447, the end portion 448, and the inner surface 449 are connected in that order to form the outer shape of the second insertion portion 440Q. The first end 446 is continuous with the opposed surface 445 of the first insertion portion 440P.

[0040] As shown in FIGS. 9 and 11 , the first end 446 of the second insertion portion 440Q is a boundary between the opposed surface 445 and the second outer peripheral surface 447. For example, the first end 446 is formed in a circular shape. As shown in FIGS. 9 and 11 , the second outer peripheral surface 447 is formed along the stacking direction V, intersecting and adjacent to the opposed surface 445. The second outer peripheral surface 447 faces the second inner peripheral surface 427 of the lid 420. For example, the second outer peripheral surface 447 is perpendicular to the opposed surface 445. The second outer peripheral surface 447 is located more inward of the lid 420 than the first outer peripheral surface 443. For example, the second outer peripheral surface 447 is formed in an annular shape when viewed from the stacking direction V. The central axis of the second outer peripheral surface 447 coincides with the central axis of the first outer peripheral surface 443. As shown in FIG. 9 , the end 448 is a boundary between the second outer peripheral surface 447 and the inner surface 449. The end 448 is the lower end of the second outer peripheral surface 447. The end 448 is formed in a circular shape, for example. The inner surface 449 is located inside the battery 1, as shown in Figure 9. The inner surface 449 is formed in a circular shape, for example.

[0041] As shown in Figures 9 and 11 , the first end 446 of the sealing plug 440 is circular. The second end 426 of the lid 420 is circular and larger than the first end 446. Therefore, the first end 446 of the sealing plug 440 is at least partially separated from the second end 426 of the lid 420. In this embodiment, the first end 446 is separated from the second end 426 along the entire circumference. The second outer peripheral surface 447 of the sealing plug 440 is separated from the second inner peripheral surface 427 of the lid 420 along the entire circumference. As shown in Figures 8 and 9 , the entire circumference refers to a 360-degree circular ring in a plane defined by the longitudinal direction X and lateral direction Y of the battery 1.

[0042] With respect to the gap S1 between the second inner peripheral surface 427 of the lid 420 and the second outer peripheral surface 447 of the sealing plug 440, the distance between the second inner peripheral surface 427 and the second outer peripheral surface 447 along the radial direction of the liquid inlet 420c is defined as length L1. The radial direction represents the radial direction centered on the central axis of the first through portion 420P and the second through portion 420Q. As an example, as shown in FIG. 9 , in a cross section cut along a plane perpendicular to the short direction Y and including the central axis of the liquid inlet 420c, the distance of the gap S1 along the longitudinal direction X corresponds to length L1. Length L1 is, for example, several hundred μm to several mm. Length L1 is, for example, 1 mm.

[0043] With respect to the gap S2 between the first inner peripheral surface 423 of the lid 420 and the first outer peripheral surface 443 of the sealing plug 440, the distance between the first inner peripheral surface 423 and the first outer peripheral surface 443 along the radial direction of the liquid inlet 420c is defined as length L2. As an example, as shown in FIG. 9 , in a cross section cut along a plane perpendicular to the short direction Y and including the central axis of the liquid inlet 420c, the distance of the gap S2 along the longitudinal direction X corresponds to length L2. Length L2 is, for example, several μm to several hundred μm. Length L2 is, for example, 10 μm. In order to laser weld the first inner peripheral surface 423 of the lid 420 and the first outer peripheral surface 443 of the sealing plug 440, length L2 is set to several μm to several hundred μm.

[0044] The shapes of the lid 420 and the sealing plug 440 are defined so that the length L1 of the gap S1 is at least partially wider than the length L2 of the gap S2. In this embodiment, the length L1 of the gap S1 is wider than the length L2 of the gap S2 around the entire circumference of the sealing plug 440. The minimum value of the length L1 of the gap S1 is wider than the maximum value of the length L2 of the gap S2. As shown on the left side of FIG. 12 , in an arbitrary cross section of the sealing plug 440 and the lid 420 parallel to the stacking direction V including the central axis of the liquid injection hole 420c of the lid 420, the length L1 of the gap S1 at one end of the sealing plug 440 is wider than the length L2 of the gap S2 between the first outer peripheral surface 443 at one end of the sealing plug 440 and the first inner peripheral surface 423 of the lid 420. As shown on the right side of Figure 12, the length L1 of the gap S1 at the other end side of the sealing plug 440 is wider than the length L2 of the gap S2 between the first outer surface 443 at the other end side of the sealing plug 440 and the first inner surface 423 of the lid 420.

[0045] The second insertion portion 440Q of the sealing plug 440 and the second through-portion 420Q of the lid 420 are not attached by press-fitting. The first insertion portion 440P of the sealing plug 440 and the first through-portion 420P of the lid 420 are not attached by press-fitting. That is, the sealing plug 440 and the lid 420 are not attached by press-fitting. After being attached to the lid 420, the sealing plug 440 is not joined to the lid 420 by expanding its diameter in a direction intersecting the stacking direction V relative to the lid 420. After being attached to the lid 420, the sealing plug 440 is not joined to the lid 420 by being pressed against the lid 420 in the stacking direction V. In other words, the sealing plug 440 is attached to the lid 420 without plastic deformation. The sealing plug 440 and the lid 420 do not have plastically deformed portions that would deform and fix them to each other. In the embodiment, when the sealing plug 440 and the lid 420 are attached, contact between the sealing plug 440 and the lid 420 may cause plastic deformation of at least one of the sealing plug 440 and the lid 420 .

[0046] The insulator 500 insulates the components of the battery 1 from the exterior body 400. The insulator 500 shown in Figures 2 to 4, 7, and 10 includes an insulating cover 510, a positive electrode side insulating plate 520, and a negative electrode side insulating plate 530.

[0047] The insulating cover 510 covers the charging / discharging unit 100 shown in Fig. 4. The insulating cover 510 exposes the upper portion of the charging / discharging unit 100 in Fig. 4 to the outside. The insulating cover 510 covers the charging / discharging unit 100 except for the upper portion in Fig. 4. The insulating cover 510 is formed, for example, in a pentahedral shape and is folded into a box shape. The insulating cover 510 is formed, for example, from polypropylene.

[0048] As shown in FIG. 2 , the positive electrode side insulating plate 520 insulates the positive electrode current collector plate 210 from the lid 420. As shown in FIGS. 2 and 7 , the positive electrode side insulating plate 520 includes a rectangular parallelepiped base portion 521 and an edge portion 522 that surrounds the base portion 521 in an annular shape and protrudes in a direction away from the lid 420. The base portion 211 of the positive electrode current collector plate 210 is accommodated in a space defined by the base portion 521 and the edge portion 522 of the positive electrode side insulating plate 520. A through hole 521 a is formed in the base portion 521. The insertion portion 612 of the positive electrode side gasket 610 is inserted into the through hole 521 a of the base portion 521. The positive electrode side insulating plate 520 is formed, for example, from an insulating resin.

[0049] As shown in FIG. 3 , the negative electrode side insulating plate 530 insulates the negative electrode current collector plate 220 from the lid 420. As shown in FIGS. 3 and 10 , the negative electrode side insulating plate 530 includes a rectangular parallelepiped base 531 and an edge 532 that surrounds the base 531 in an annular shape and protrudes in a direction away from the lid 420. The base 221 of the negative electrode current collector plate 220 is accommodated in a space defined by the base 531 and the edge 532 of the negative electrode side insulating plate 530. A through hole 531 a is formed in the base 531. The insertion portion 622 of the negative electrode side gasket 620 is inserted into the through hole 531 a of the base 531. The negative electrode side insulating plate 530 is formed, for example, from an insulating resin.

[0050] The sealing body 600 seals the components of the battery 1 and the exterior body 400. The sealing body 600 shown in Figures 1 to 4, 7 and 10 includes a positive electrode side gasket 610 and a negative electrode side gasket 620.

[0051] The positive electrode side gasket 610 is compressed by the positive electrode terminal 310 and the lid 420, thereby sealing the positive electrode terminal 310 and the lid 420. As shown in FIG. 7 , the positive electrode side gasket 610 includes a rectangular plate-shaped base 611 and a cylindrical insertion portion 612 that protrudes inward from the center of the base 611 toward the inside of the battery 1. The positive electrode side gasket 610 also includes an edge portion 613 that surrounds the base 611 in an annular shape and protrudes outward from the battery 1. A through hole is formed in the base 611. The base 311 of the positive electrode terminal 310 is accommodated in the space defined by the base 611 and the edge portion 613 of the positive electrode side gasket 610. The insertion portion 612 is inserted into the positive electrode side insertion hole 420a of the lid 420, as shown in FIG. 2 . 2, the insertion portion 312 of the positive terminal 310 is inserted into the through hole of the base portion 611 and the inner circumferential surface of the insertion portion 612. The positive electrode side gasket 610 is formed, for example, from an insulating resin that has insulating properties and elasticity.

[0052] The negative electrode side gasket 620 is compressed by the negative electrode terminal 320 and the lid 420, thereby sealing the negative electrode terminal 320 and the lid 420. The external shape of the negative electrode side gasket 620 is similar to that of the positive electrode side gasket 610. As shown in FIG. 10 , the negative electrode side gasket 620 includes a rectangular plate-shaped base 621 and a cylindrical insertion portion 622 that protrudes inward from the center of the base 621 toward the inside of the battery 1. The negative electrode side gasket 620 also includes an edge portion 623 that surrounds the base 621 in an annular shape and protrudes outward from the battery 1. A through hole is formed in the base 621. The base 321 of the negative electrode terminal 320 is accommodated in the space defined by the base 621 and the edge portion 623 of the negative electrode side gasket 620. The insertion portion 622 is inserted into the negative electrode side insertion hole 420b of the lid 420, as shown in FIG. 3 . 3, the insertion portion 322 of the negative electrode terminal 320 is inserted into the through hole of the base portion 621 and the inner circumferential surface of the insertion portion 622. The negative electrode side gasket 620 is formed, for example, from an insulating resin that has insulating properties and elasticity.

[0053] (Manufacturing Method of Battery 1 of the Embodiment) The manufacturing method of battery 1 of the embodiment is characterized only by the attachment and joining of sealing plug 440 and lid 420. Therefore, in the manufacturing method of battery 1 of the embodiment, only the attachment and joining of sealing plug 440 and lid 420 will be described with reference to Figures 11 and 12. Figure 12 is an end view showing the attachment and joining of sealing plug 440 and lid 420 in the manufacturing method of battery 1 of the embodiment.

[0054] The manufacturing method of the battery 1 of the embodiment includes a first step and a second step. In the first step, the lid 420 and the sealing plug 440 are attached by bringing the opposing surface 425 of the lid 420 and the opposed surface 445 of the sealing plug 440 into contact with each other along the stacking direction V, with the opposing surface 425 of the lid 420 and the opposed surface 445 of the sealing plug 440 facing each other in the stacking direction V. In the second step, after the first step, the lid 420 and the sealing plug 440 are welded together.

[0055] In the first step, when attaching the sealing plug 440 and the lid 420, the sealing plug 440 and the lid 420 are brought relatively close to each other, the sealing plug 440 is brought close to the lid 420, or the lid 420 is brought close to the sealing plug 440. In the embodiment, as an example, a configuration will be described in which the sealing plug 440 is attached to and joined to the lid 420 by bringing the sealing plug 440 close to the lid 420.

[0056] In the sealing plug 440, the first insertion portion 440P has a larger surface area in the longitudinal direction X and the lateral direction Y intersecting the stacking direction V than the second insertion portion 440Q. In the lid 420, the first penetration portion 420P has a larger opening area in the longitudinal direction X and the lateral direction Y intersecting the stacking direction V than the second penetration portion 420Q. Therefore, when attaching the sealing plug 440 to the lid 420, the second insertion portion 440Q of the sealing plug 440 is brought close to the first penetration portion 420P of the lid 420 along the stacking direction V so that the sealing plug 440 and the lid 420 do not interfere with each other.

[0057] With the opposed surface 445 of the sealing plug 440 and the opposing surface 425 of the lid 420 facing each other in the stacking direction V, the sealing plug 440 is brought closer to the lid 420. In FIG. 12 , the sealing plug 440 shown by the dashed line is in a state before being attached to the lid 420. Here, as shown by the dashed line in FIG. 12 , it is assumed that the sealing plug 440 before being attached to the lid 420 is tilted with respect to the lid 420. In FIG. 12 , the sealing plug 440 shown by the solid line is in a state after being attached to the lid 420. As the sealing plug 440 approaches the lid 420, the second insertion portion 440Q of the sealing plug 440 is first inserted into the first penetration portion 420P of the lid 420, and then inserted into the second penetration portion 420Q of the lid 420.

[0058] When attaching the sealing plug 440 to the lid 420, if the sealing plug 440 and the lid 420 are tilted relative to each other with respect to a direction intersecting the stacking direction V, the second insertion portion 440Q is more likely to interfere with the lid 420 than the first insertion portion 440P. This is because, when the sealing plug 440 and the lid 420 are tilted relative to each other, the positional deviation in the direction intersecting the stacking direction V is proportional to the distance along the stacking direction V. As a result, the longer the total length of the sealing plug 440 inserted into the lid 420, the more likely it is to interfere with the lid 420. Specifically, as shown in FIGS. 11 and 12 , when attaching the sealing plug 440 to the lid 420, the first insertion portion 440P of the sealing plug 440 needs to suppress interference with the lid 420 within a first length t1. The first length t1 is the length of the first penetration portion 420P of the lid 420 along the stacking direction V. 11 and 12 , when attaching the sealing plug 440 to the lid 420, the second insertion portion 440Q of the sealing plug 440 needs to suppress interference with the lid 420 within a range of a second length t2. The second length t2 is the length along the stacking direction V of the first through portion 420P and the second through portion 420Q of the lid 420. The second length t2 is longer than the first length t1 by the length along the stacking direction V of the second through portion 420Q. Therefore, in the sealing plug 440, the second insertion portion 440Q is more likely to interfere with the lid 420 than the first insertion portion 440P.

[0059] 12 , in the battery 1 of the embodiment, the length L1 of the gap S1 between the second inner circumferential surface 427 of the lid 420 and the second outer circumferential surface 447 of the sealing stopper 440 is wider than the length L2 of the gap S2 between the first inner circumferential surface 423 of the lid 420 and the first outer circumferential surface 443 of the sealing stopper 440. That is, in the battery 1 of the embodiment, the second insertion portion 440Q of the sealing stopper 440, which has a relatively long insertion length (second length t2) into the lid 420, has a larger gap with the lid 420 than the first insertion portion 440P, which has a relatively short insertion length (first length t1) into the lid 420. Therefore, in the sealing stopper 440, the second insertion portion 440Q has a relatively wider gap with the lid 420 than the first insertion portion 440P, and the margin for positioning errors such as tilt is relatively larger. Therefore, even if the sealing plug 440 and the lid 420 are tilted relative to each other when attaching the sealing plug 440 and the lid 420, interference between the sealing plug 440 and the lid 420 is suppressed. As a result, the sealing plug 440 and the lid 420 can be attached sufficiently in the battery 1 of this embodiment.

[0060] In this embodiment, as shown in FIG. 12 , the first length t1 is longer than the second length t2. Although different from the configuration of the embodiment, the length L1 shown in FIG. 12 is set to the length L3 shown in FIG. 12 . The length L3 corresponds to the length L2. Setting the length L1 to the length L3 (L2) is intended to equalize the gap between the first insertion portion 440P of the sealing plug 440 and the first penetration portion 420P of the lid 420 and the gap between the second insertion portion 440Q of the sealing plug 440 and the second penetration portion 420Q of the lid 420. In this case, the second inner circumferential surface 427 of the second penetration portion 420Q of the lid 420 becomes the second inner circumferential surface 427′ represented by the two-dot chain line. Here, in FIG. 12 , the sealing plug 440, indicated by the dashed line, is tilted relative to the lid 420 and is being attached to the lid 420. In this case, in a configuration different from the embodiment, an end 448' of the second insertion portion 440Q of the sealing plug 440, shown by the dashed line, may interfere with the second inner circumferential surface 427', shown by the two-dot chain line.

[0061] In the second step, the sealing plug 440 and the lid 420 are welded together. In the embodiment, the sealing plug 440 and the lid 420 are laser-welded, for example. As shown in Fig. 12, a weld W1 is formed between the first outer circumferential surface 443 of the sealing plug 440 and the end 422 of the lid 420. The weld W1 is formed in an annular shape along the end 422 of the lid 420.

[0062] (Effects of Battery 1 and Manufacturing Method of Battery 1 of the Embodiment) The effects of the battery 1 and manufacturing method of the battery 1 of the embodiment will be described with reference to FIGS. 9, 11, and 12. FIG.

[0063] (1) As shown in FIG. 11 , the length L1 of the gap S1 between the second inner peripheral surface 427 of the lid 420 and the second outer peripheral surface 447 of the sealing plug 440 is at least partially wider than the length L2 of the gap S2 between the first inner peripheral surface 423 of the lid 420 and the first outer peripheral surface 443 of the sealing plug 440.

[0064] (18) As shown in Fig. 12 , the manufacturing method of the battery 1 includes a first step and a second step. In the first step, the lid 420 and the sealing plug 440 are attached by bringing the opposing surface 425 of the lid 420 and the opposed surface 445 of the sealing plug 440 into contact with each other along the stacking direction V, with the opposing surface 425 of the lid 420 and the opposed surface 445 of the sealing plug 440 facing each other in the stacking direction V. In the second step, after the first step, the lid 420 and the sealing plug 440 are welded together.

[0065] According to this configuration, in the sealing plug 440, the second insertion portion 440Q, which has a relatively long insertion length (second length t2) into the lid 420, has a larger gap with the lid 420 in a direction intersecting the stacking direction V than the first insertion portion 440P, which has a relatively short insertion length (first length t1) into the lid 420. Therefore, in the sealing plug 440, the second insertion portion 440Q has a relatively wider gap with the lid 420 in a direction intersecting the stacking direction V than the first insertion portion 440P. That is, in the sealing plug 440, the second insertion portion 440Q has a relatively larger margin of positioning error in the direction intersecting the stacking direction V than the first insertion portion 440P. The positioning error of the sealing plug 440 occurs due to the sealing plug 440 being tilted from the stacking direction V. Therefore, even if the sealing plug 440 and the lid 420 are tilted relative to each other when attaching the sealing plug 440 and the lid 420, interference between the sealing plug 440 and the lid 420 can be suppressed. As a result, the sealing plug 440 and the lid 420 can be sufficiently attached and joined.

[0066] More specifically, in the battery 1 of this embodiment, when attaching the sealing stopper 440 to the lid 420, the sealing stopper 440 can be smoothly inserted into the lid 420. This prevents the sealing stopper 440 from being attached to the lid 420 in a state where it is partially raised relative to the lid 420. That is, this prevents the sealing stopper 440 from being attached to the lid 420 in a state where it is tilted relative to the lid 420. This also prevents the sealing stopper 440 from being attached to the lid 420 in a state where it is entirely raised relative to the lid 420. This also prevents the sealing stopper 440 from being attached to the lid 420 in a state where it is distorted or bent relative to the lid 420. As a result, the sealing stopper 440 and the lid 420 can be sufficiently joined by, for example, welding.

[0067] Furthermore, in the sealing plug 440, the second insertion portion 440Q has a relatively larger gap with the liquid inlet 420c of the lid 420 in the direction intersecting the stacking direction V than the first insertion portion 440P, and this increases the likelihood of dimensional tolerance at the second insertion portion 440Q. That is, the sealing plug 440 can relax the dimensional tolerance at the second insertion portion 440Q. Furthermore, the dimensional tolerance at the portion of the liquid inlet 420c of the lid 420 that is adjacent to the second insertion portion 440Q of the sealing plug 440 in the direction intersecting the stacking direction V can be relaxed.

[0068] Furthermore, in the sealing plug 440, the second insertion portion 440Q has a relatively larger gap with the liquid injection hole 420c of the lid 420 in the direction intersecting the stacking direction V than the first insertion portion 440P, so the second insertion portion 440Q can be made smaller and lighter.

[0069] Furthermore, in the sealing plug 440, the gap between the second insertion portion 440Q and the liquid inlet 420c of the lid 420 in the direction intersecting the stacking direction V is relatively larger than that between the first insertion portion 440P and the first insertion portion 440P, which increases the likelihood of dimensional tolerance for concentricity between the first insertion portion 440P and the second insertion portion 440Q. That is, the sealing plug 440 can relax the dimensional tolerance of the second insertion portion 440Q. Furthermore, the dimensional tolerance of the portion of the liquid inlet 420c of the lid 420 that is adjacent to the second insertion portion 440Q of the sealing plug 440 in the direction intersecting the stacking direction V can be relaxed.

[0070] (2) As shown in FIG. 11 , the length L1 of the gap S1 between the second inner circumferential surface 427 of the lid 420 and the second outer circumferential surface 447 of the sealing plug 440 is wider than the length L2 of the gap S2 between the first inner circumferential surface 423 of the lid 420 and the first outer circumferential surface 443 of the sealing plug 440. This configuration corresponds to a configuration in which the length L1 is wider than the length L2 by a certain amount. That is, this configuration is such that even when the sealing plug 440 is maximally eccentric relative to the lid 420 in a direction intersecting the stacking direction V and the first outer circumferential surface 443 of the sealing plug 440 comes into contact with the first inner circumferential surface 423 of the lid 420, the second outer circumferential surface 447 of the sealing plug 440 does not come into contact with the second inner circumferential surface 427 of the lid 420. This configuration sufficiently suppresses interference between the sealing plug 440 and the lid 420, allowing the sealing plug 440 to be securely attached to the lid 420.

[0071] 11 , the first end 446 located at the boundary between the opposed surface 445 and the second outer peripheral surface 447 of the sealing plug 440 is at least partially separated from the second end 426 located at the boundary between the opposed surface 425 and the second inner peripheral surface 427 of the lid 420. This configuration corresponds to a configuration in which the length L1 of the gap S1 between the second inner peripheral surface 427 of the lid 420 and the second outer peripheral surface 447 of the sealing plug 440 is at least partially wider than the length L2 of the gap S2 between the first inner peripheral surface 423 of the lid 420 and the first outer peripheral surface 443 of the sealing plug 440. This configuration can prevent the end 448 of the sealing plug 440 from interfering with the second inner peripheral surface 427 of the lid 420, and can prevent the sealing plug 440 from being attached at an angle to the lid 420.

[0072] (4) As shown in FIG. 11 , the first end 446 is spaced apart from the second end 426. This configuration corresponds to a configuration in which the length L1 is greater than the length L2 by a certain amount. That is, this configuration is such that even when the sealing plug 440 is maximally eccentric relative to the lid 420 in a direction intersecting the stacking direction V and the first outer peripheral surface 443 of the sealing plug 440 contacts the first inner peripheral surface 423 of the lid 420, the second outer peripheral surface 447 of the sealing plug 440 does not contact the second inner peripheral surface 427 of the lid 420. This configuration sufficiently suppresses interference between the sealing plug 440 and the lid 420, allowing the sealing plug 440 to be securely attached to the lid 420.

[0073] 11 , the opposed surface 445 of the sealing plug 440 is in partial surface contact with the opposed surface 425 of the lid 420 in a region along a direction intersecting the stacking direction V from the first inner peripheral surface 423 of the lid 420 to the second outer peripheral surface 447 of the sealing plug 440. With this configuration, the sealing plug 440 and the lid 420 can be joined after the sealing plug 440 and the lid 420 have been sufficiently positioned.

[0074] (6) As shown in Figure 11, the second insertion portion 440Q of the sealing plug 440 and the second penetration portion 420Q of the lid 420 are not attached by press-fitting. This configuration sufficiently prevents the sealing plug 440 from being attached to the lid 420 in a distorted or bent state relative to the lid 420. As a result, the sealing plug 440 and the lid 420 can be sufficiently joined by, for example, welding. Furthermore, this configuration does not require a press-fitting device during battery 1 manufacturing.

[0075] (7) As shown in FIG. 11 , the sealing plug 440 and the lid 420 are not attached by press-fitting. That is, the second insertion portion 440Q of the sealing plug 440 and the second penetration portion 420Q of the lid 420 are not attached by press-fitting. Furthermore, the first insertion portion 440P of the sealing plug 440 and the first penetration portion 420P of the lid 420 are not attached by press-fitting. This configuration further sufficiently prevents the sealing plug 440 from being attached to the lid 420 in a distorted or bent state relative to the lid 420. As a result, the sealing plug 440 and the lid 420 can be sufficiently joined by, for example, welding. Furthermore, this configuration eliminates the need for a press-fitting device in the manufacture of the battery 1.

[0076] (15) As shown in Figures 9 and 12, the minimum value of the length L1 of the gap S1 between the second inner circumferential surface 427 of the lid 420 and the second outer circumferential surface 447 of the sealing plug 440 is wider than the maximum value of the length L2 of the gap S2 between the first inner circumferential surface 423 of the lid 420 and the first outer circumferential surface 443 of the sealing plug 440. This configuration can further sufficiently prevent the sealing plug 440 from being attached to the lid 420 in a distorted or bent state relative to the lid 420. As a result, the sealing plug 440 and the lid 420 can be sufficiently joined, for example, by welding. Furthermore, this configuration eliminates the need for a press-fitting device in the manufacture of the battery 1.

[0077] (16) As shown in FIG. 12 , in any cross section of the sealing stopper 440 and the lid 420 parallel to the stacking direction V including the central axis of the liquid inlet 420c of the lid 420, the length L1 of the gap S1 between the second outer peripheral surface 447 at one end of the sealing stopper 440 and the second inner peripheral surface 427 of the lid 420 is wider than the length L2 of the gap S2 between the first outer peripheral surface 443 at one end of the sealing stopper 440 and the first inner peripheral surface 423 of the lid 420. The one end side is, for example, the left side in the longitudinal direction X of the battery 1 in FIG. 12 . The length L1 of the gap S1 between the second outer peripheral surface 447 at the other end of the sealing stopper 440 and the second inner peripheral surface 427 of the lid 420 is wider than the length L2 of the gap S2 between the first outer peripheral surface 443 at the other end of the sealing stopper 440 and the first inner peripheral surface 423 of the lid 420. The other end side is, for example, the right side in the longitudinal direction X of the battery 1 in FIG. 12 . In other words, the other end side is the side that is 180 degrees opposite from the one end side along the central axis of the liquid inlet 420c of the lid 420. The one end side may be one end side in the short-side direction Y of the battery 1, and the other end side may be the other end side in the short-side direction Y of the battery 1. This configuration can further sufficiently prevent the sealing plug 440 from being attached to the lid 420 in a state where it is distorted or bent relative to the lid 420. As a result, the sealing plug 440 and the lid 420 can be sufficiently joined by, for example, welding. Furthermore, this configuration eliminates the need for a press-fitting device during battery 1 manufacturing.

[0078] (Sealing plug 710 of modified example 1 of embodiment) The sealing plug 710 of modified example 1 of the embodiment will be described with reference to Fig. 13. Fig. 13 is an end view showing a main part of an exterior body 400A of modified example 1 of the embodiment.

[0079] 13 , the exterior body 400A includes a sealing plug 710 instead of the sealing plug 440 of the embodiment. The sealing plug 710 includes a first insertion portion 440P and a second insertion portion 710Q. The configuration of the second insertion portion 710Q is the same as the configuration of the second insertion portion 440Q of the sealing plug 440 of the embodiment, except for the shape of the second outer circumferential surface 717.

[0080] 13 of the first modified example of the embodiment, the same components as those in the first modified example are assigned the same reference numerals as those in the first modified example, and the description thereof will be omitted. In FIG. 13 of the first modified example of the embodiment, the components different from those in the first modified example are assigned the same reference numerals as those in the first modified example.

[0081] In the sealing plug 710, the second outer peripheral surface 717 narrows in a direction intersecting the stacking direction V from the outside to the inside of the lid 420. The outside of the lid 420 is the side of the outer surface 421 of the lid 420, which corresponds to the outside of the battery 1. The inside of the lid 420 is the side of the inner surface 429 of the lid 420, which corresponds to the inside of the battery 1. The directions intersecting the stacking direction V are the longitudinal direction X and the lateral direction Y. The second outer peripheral surface 717 forms an inclined surface intersecting the stacking direction V in the second insertion portion 710Q. The second outer peripheral surface 717 is formed linearly in the second insertion portion 710Q. The second outer peripheral surface 717 is inclined from the outside to the inside of the lid 420, away from the second inner peripheral surface 427 of the second penetration portion 420Q. The second insertion portion 710Q is formed into a truncated cone shape by the second outer peripheral surface 717. The cross-sectional shape of the second insertion portion 710Q, defined by planes in the longitudinal direction X and the lateral direction Y, becomes smaller from the outside to the inside of the lid 420.

[0082] The second outer peripheral surface 717 is not limited to the linearly inclined configuration in which it slopes from the outside to the inside of the lid 420, moving away from the second inner peripheral surface 427 of the second penetrating portion 420Q, as in the first modified example of the embodiment. The second outer peripheral surface 717 may be formed in an arc shape that is concavely curved in a direction intersecting the stacking direction V, moving away from the second inner peripheral surface 427 of the second penetrating portion 420Q, moving from the outside to the inside of the lid 420. The concavely curved arc shape of the second outer peripheral surface 717 refers to a shape that is recessed toward the interior of the second insertion portion 710Q. The second outer peripheral surface 717 may also be formed in a convexly curved arc shape in a direction intersecting the stacking direction V, moving from the outside to the inside of the lid 420. When the second outer peripheral surface 717 is formed in a convexly curved arc shape, it is formed in an arc shape that is farther from the second inner peripheral surface 427 of the lid 420 than the inclined surface shown in FIG. 13 .

[0083] The second outer peripheral surface 717 is not limited to the configuration in which it is formed over the entire area of ​​the second insertion portion 710Q along the stacking direction V, as in the first modified example of the embodiment. The second outer peripheral surface 717 may be formed over only a portion of the second insertion portion 710Q along the stacking direction V. Specifically, the second insertion portion 710Q may be configured, for example, by combining the inclined second outer peripheral surface 717 shown in FIG. 13 with the vertical second outer peripheral surface 447 shown in FIG. 11 . In this configuration, the inclined second outer peripheral surface 717 is formed at the tip end portion of the second insertion portion 710Q, and the vertical second outer peripheral surface 447 is formed at the base end portion of the second insertion portion 710Q. The tip end portion is located closer to the inside of the battery 1 than the base end portion. In other words, in this configuration, the second insertion portion 710Q has a configuration combining a truncated cone shape and a cylindrical shape.

[0084] 13 , the second outer peripheral surface 717 of the sealing plug 710 narrows in a direction intersecting the stacking direction V from the outside to the inside of the lid 420. This configuration allows the gap between the second outer peripheral surface 717 of the sealing plug 710 and the second inner peripheral surface 427 of the lid 420 to be increased from the outside to the inside of the lid 420, where the insertion length of the sealing plug 710 into the lid 420 becomes relatively longer. The positioning error of the second outer peripheral surface 717 of the sealing plug 710 relative to the second inner peripheral surface 427 of the lid 420 increases from the outside to the inside of the lid 420. However, the margin of error for the positioning error of the second outer peripheral surface 717 of the sealing plug 710 relative to the second inner peripheral surface 427 of the lid 420 is relatively larger in the portion of the sealing plug 710 located inside the lid 420 than in the portion of the sealing plug 710 located outside the lid 420. Therefore, even if the sealing plug 710 and the lid 420 are tilted relative to each other when attaching the sealing plug 710 and the lid 420, interference between the second outer peripheral surface 717 of the sealing plug 710 and the lid 420 can be suppressed. As a result, the sealing plug 710 and the lid 420 can be sufficiently attached and joined.

[0085] The second outer peripheral surface 717 of the sealing plug 710 does not need to be narrowed in a direction intersecting the stacking direction V in the entire region along the stacking direction V from the outside to the inside of the lid 420. The second outer peripheral surface 717 may be configured to be narrowed in a direction intersecting the stacking direction V only in a partial region along the stacking direction V from the outside to the inside of the lid 420. In other words, the second outer peripheral surface 717 may be configured to include a portion that is narrowed in a direction intersecting the stacking direction V from the outside to the inside of the lid 420.

[0086] (Sealing plug 720 of modified example 2 of embodiment) A sealing plug 720 of modified example 2 of the embodiment will be described with reference to Fig. 14. Fig. 14 is an end view showing a main part of an exterior body 400B of modified example 2 of the embodiment.

[0087] (Configuration of sealing plug 720 in modified example 2 of embodiment) As shown in Fig. 14 , the exterior body 400B includes a sealing plug 720 instead of the sealing plug 440 of the embodiment. The sealing plug 720 includes a first insertion portion 720P and a second insertion portion 440Q. The configuration of the first insertion portion 720P is similar to the configuration of the first insertion portion 440P of the sealing plug 440 of the embodiment, except for the shape of the first outer peripheral surface 723.

[0088] 14 of the second modification of the embodiment, the same components as those in the embodiment are denoted by the same reference numerals as those in the embodiment, and the description thereof will be omitted. In FIG. 14 of the second modification of the embodiment, the components different from those in the embodiment are denoted by different reference numerals as those in the embodiment.

[0089] In the sealing plug 720, the first outer peripheral surface 723 narrows in a direction intersecting the stacking direction V from the outside to the inside of the lid 420. The outside of the lid 420 is the side of the outer surface 421 of the lid 420, which corresponds to the outside of the battery 1. The inside of the lid 420 is the side of the inner surface 429 of the lid 420, which corresponds to the inside of the battery 1. The directions intersecting the stacking direction V are the longitudinal direction X and the lateral direction Y. The first outer peripheral surface 723 forms an inclined surface intersecting the stacking direction V in the first insertion portion 720P. The first outer peripheral surface 723 is formed linearly in the first insertion portion 720P. The first outer peripheral surface 723 inclines from the outside to the inside of the lid 420, away from the first inner peripheral surface 423 of the first penetration portion 420P. The first insertion portion 720P is formed into a truncated cone shape by the first outer peripheral surface 723. The cross-sectional shape of the first insertion portion 720P, defined by planes in the longitudinal direction X and the lateral direction Y, becomes smaller from the outside to the inside of the lid 420.

[0090] The first outer peripheral surface 723 is not limited to a linearly inclined configuration, as in the second modification of the embodiment, from the outside to the inside of the lid 420, away from the first inner peripheral surface 423 of the first penetrating portion 420P. The first outer peripheral surface 723 may be formed in an arc shape that is concavely curved in a direction intersecting the stacking direction V, from the outside to the inside of the lid 420, away from the first inner peripheral surface 423 of the first penetrating portion 420P. The concavely curved arc shape of the first outer peripheral surface 723 refers to a shape that is recessed toward the interior of the first insertion portion 720P. The first outer peripheral surface 723 may also be formed in a convexly curved arc shape from the outside to the inside of the lid 420, in a direction intersecting the stacking direction V. When the first outer peripheral surface 723 is formed in a convexly curved arc shape, the arc shape is farther from the first inner peripheral surface 423 of the lid 420 than the inclined surface shown in FIG. 14 .

[0091] The first outer peripheral surface 723 is not limited to a configuration in which it is formed over the entire area of ​​the first insertion portion 720P along the stacking direction V, as in the second modification of the embodiment. The first outer peripheral surface 723 may be formed over only a portion of the first insertion portion 720P along the stacking direction V. Specifically, the first insertion portion 720P may be configured, for example, by combining the inclined first outer peripheral surface 723 shown in FIG. 14 with the vertical first outer peripheral surface 443 shown in FIG. 11 . In this configuration, the inclined first outer peripheral surface 723 is formed at the tip end portion of the first insertion portion 720P, and the vertical first outer peripheral surface 443 is formed at the base end portion of the first insertion portion 720P. The tip end portion is located closer to the inside of the battery 1 than the base end portion. In other words, in this configuration, the first insertion portion 720P has a configuration combining a truncated cone shape and a cylindrical shape.

[0092] 14 , the first outer peripheral surface 723 of the sealing plug 720 narrows in a direction intersecting the stacking direction V from the outside to the inside of the lid 420. This configuration allows the gap between the first outer peripheral surface 723 of the sealing plug 720 and the first inner peripheral surface 423 of the lid 420 to be increased from the outside to the inside of the lid 420, where the insertion length of the sealing plug 720 into the lid 420 becomes relatively longer. The positioning error of the first outer peripheral surface 723 of the sealing plug 720 relative to the first inner peripheral surface 423 of the lid 420 increases from the outside to the inside of the lid 420. However, the margin of error for the positioning error of the first outer peripheral surface 723 of the sealing plug 720 relative to the first inner peripheral surface 423 of the lid 420 is relatively larger in the portion located inside the lid 420 than in the portion located outside the lid 420. Therefore, even if the sealing plug 720 and the lid 420 are tilted relative to each other when attaching the sealing plug 720 and the lid 420, interference between the first outer peripheral surface 723 of the sealing plug 720 and the lid 420 can be suppressed. As a result, the sealing plug 720 and the lid 420 can be sufficiently attached and joined.

[0093] The first outer peripheral surface 723 of the sealing plug 720 does not need to be narrowed in a direction intersecting the stacking direction V in the entire region along the stacking direction V from the outside to the inside of the lid 420. The first outer peripheral surface 723 may be configured to be narrowed in a direction intersecting the stacking direction V only in a partial region along the stacking direction V from the outside to the inside of the lid 420. In other words, the first outer peripheral surface 723 may be configured to include a portion that is narrowed in a direction intersecting the stacking direction V from the outside to the inside of the lid 420.

[0094] (Sealing plug 730 of modified example 3 of embodiment) A sealing plug 730 of modified example 3 of the embodiment will be described with reference to Fig. 15. Fig. 15 is an end view showing a main part of an exterior body 400C of modified example 3 of the embodiment.

[0095] 15 , the exterior body 400C includes a sealing plug 730 instead of the sealing plug 440 of the embodiment. The sealing plug 730 includes a first insertion portion 440P and a second insertion portion 730Q. The configuration of the second insertion portion 730Q is the same as the configuration of the second insertion portion 440Q of the sealing plug 440 of the embodiment, except for the shape of the third end portion 738.

[0096] 15 of the third modification of the embodiment, the same components as those in the embodiment are denoted by the same reference numerals as those in the embodiment, and the description thereof will be omitted. In FIG. 15 of the third modification of the embodiment, the components different from those in the embodiment are denoted by different reference numerals as those in the embodiment.

[0097] The third end 738 of the second outer peripheral surface 447 of the sealing plug 730, located at the inner end of the lid 420, is formed in an arc shape. The inside of the lid 420 is the side of the inner surface 429 of the lid 420, which corresponds to the inside of the battery 1. The third end 738 is located at the boundary between the second outer peripheral surface 447 and the inner surface 429. The third end 738 is configured by the boundary between the second outer peripheral surface 447 and the inner surface 429 being formed in an arc shape. The third end 738 is contained within the area formed by the imaginary line extending the second outer peripheral surface 447 downward in FIG. 15 and the imaginary line extending the inner surface 429 to the left in FIG. 15 .

[0098] 15 , the third end 738 of the second outer peripheral surface 447 of the sealing plug 730, which is located inside the lid 420, is formed in an arc shape. This configuration maximizes the gap between the third end 738, at which the sealing plug 730 is inserted into the lid 420 by the longest distance, and the second inner peripheral surface 427 of the lid 420. Because the third end 738 of the sealing plug 730 is located at the innermost position of the lid 420, the positioning error relative to the second inner peripheral surface 427 of the lid 420 is the largest. However, because the third end 738 of the sealing plug 730 is rounded in an arc shape, the margin of error for positioning relative to the second inner peripheral surface 427 of the lid 420 is the largest in a direction intersecting the stacking direction V. Therefore, even if the sealing plug 730 and the lid 420 are tilted relative to each other when attaching the sealing plug 730 and the lid 420, interference between the third end 738 of the sealing plug 730 and the lid 420 can be suppressed. As a result, the sealing plug 730 and the lid 420 can be sufficiently attached and joined. Because the third end 738 of the sealing plug 730 is formed in an arc shape, it is possible to reduce the load that would occur if the third end 738 interfered with the second inner circumferential surface 427 of the lid 420, etc. This makes it possible to reduce the load that would occur during interference on at least one of the sealing plug 730 and the lid 420.

[0099] For example, the third end 738 may be formed in a linear shape that is inclined with respect to the stacking direction V when viewed from a direction perpendicular to the stacking direction V. That is, the third end 738 may be formed in a notched shape. The direction perpendicular to the stacking direction V is, for example, the short-side direction Y. In this case, the third end 738 is configured by forming an inclined surface at the boundary between the second outer peripheral surface 447 and the inner surface 429. This inclined surface is inclined from the outside to the inside of the lid 420, moving away from the second inner peripheral surface 427 of the second penetrating portion 420Q. The outside of the lid 420 is the outside of the battery 1. The inside of the lid 420 is the inside of the battery 1.

[0100] (Sealing plug 740 of modified example 4 of embodiment) A sealing plug 740 of modified example 4 of the embodiment will be described with reference to Fig. 16. Fig. 16 is an end view showing a main part of an exterior body 400D of modified example 4 of the embodiment.

[0101] 16 , the exterior body 400D includes a sealing plug 740 instead of the sealing plug 440 of the embodiment. The sealing plug 740 includes a first insertion portion 740P and a second insertion portion 440Q. The configuration of the first insertion portion 740P is the same as the configuration of the first insertion portion 440P of the sealing plug 440 of the embodiment, except for the shape of the fourth end portion 744.

[0102] 16 of the fourth modification of the embodiment, the same components as those in the embodiment are denoted by the same reference numerals as those in the embodiment, and the description thereof will be omitted. In FIG. 16 of the fourth modification of the embodiment, the components different from those in the embodiment are denoted by different reference numerals as those in the embodiment.

[0103] The fourth end 744 of the sealing plug 740 is located at the boundary between the first outer peripheral surface 443 and the opposed surface 445. The fourth end 744 is configured by an arc-shaped boundary between the first outer peripheral surface 443 and the opposed surface 445. The fourth end 744 is contained within a region defined by an imaginary line extending the first outer peripheral surface 443 downward in Fig. 16 and an imaginary line extending the opposed surface 445 leftward in Fig. 16 .

[0104] (Effects of the sealing plug 740 of the fourth modification of the embodiment) (11) As shown in FIG. 16 , the fourth end 744 located at the boundary between the first outer peripheral surface 443 of the sealing plug 740 and the opposed surface 445 is formed in an arc shape. This configuration maximizes the gap between the fourth end 744, at which the sealing plug 740 is inserted into the lid 420 by the longest length, and the first inner peripheral surface 423 of the lid 420 in the first insertion portion 740P. Because the fourth end 744 of the sealing plug 740 is located at the innermost side of the lid 420 (the side closest to the charge / discharge unit 100) in the first insertion portion 740P, the positioning error relative to the first inner peripheral surface 423 of the lid 420 is the largest. However, because the fourth end 744 of the sealing plug 740 is rounded in an arc shape, the margin of positioning error relative to the first inner peripheral surface 423 of the lid 420 is the largest in a direction intersecting the stacking direction V. Therefore, even if the sealing plug 740 and the lid 420 are tilted relative to each other when attaching the sealing plug 740 and the lid 420, interference between the fourth end 744 of the sealing plug 740 and the lid 420 can be suppressed. As a result, the sealing plug 740 and the lid 420 can be sufficiently attached and joined. Because the fourth end 744 of the sealing plug 740 is formed in an arc shape, it is possible to reduce the load that would occur if the fourth end 744 interferes with the first inner circumferential surface 423 of the lid 420, etc. This makes it possible to reduce the load that would occur during interference on at least one of the sealing plug 740 and the lid 420.

[0105] For example, the fourth end 744 may be formed in a linear shape that is inclined with respect to the stacking direction V when viewed from a direction perpendicular to the stacking direction V. That is, the fourth end 744 may be formed in a notched shape. The direction perpendicular to the stacking direction V is, for example, the short-side direction Y. In this case, the fourth end 744 is configured by forming an inclined surface at the boundary between the first outer peripheral surface 443 and the opposed surface 445. This inclined surface is inclined from the outside to the inside of the lid 420, moving away from the first inner peripheral surface 423 of the first penetrating portion 420P. The outside of the lid 420 is the outside of the battery 1. The inside of the lid 420 is the inside of the battery 1.

[0106] (Sealing plug 750 of modified example 5 of embodiment) A sealing plug 750 of modified example 5 of the embodiment will be described with reference to Fig. 17. Fig. 17 is an end view showing a main part of an exterior body 400E of modified example 5 of the embodiment.

[0107] 17 , the exterior body 400E includes a sealing plug 750 instead of the sealing plug 440 of the embodiment. The sealing plug 750 includes a first insertion portion 440P and a second insertion portion 750Q. The configuration of the second insertion portion 750Q is the same as the configuration of the second insertion portion 440Q of the sealing plug 440 of the embodiment, except for the shape of the fifth end portion 756.

[0108] 17 of the fifth modified example of the embodiment, the same components as those in the embodiment are denoted by the same reference numerals as those in the embodiment, and the description thereof will be omitted. In FIG. 17 of the fifth modified example of the embodiment, the components different from those in the embodiment are denoted by different reference numerals as those in the embodiment.

[0109] In the sealing plug 750, the fifth end 756 is configured such that the boundary between the opposed surface 445 and the second outer peripheral surface 447 is formed in an arc shape. The fifth end 756 is formed in a concavely curved arc shape. The concavely curved arc shape of the fifth end 756 means that, when protruding from the first insertion portion 440P and the second insertion portion 750Q, the fifth end 756 is recessed toward the first insertion portion 440P and the second insertion portion 750Q. The fifth end 756 protrudes toward the lid 420 from a region defined by an imaginary line extending the opposed surface 445 to the right in FIG. 17 and an imaginary line extending the second outer peripheral surface 447 upward in FIG. 17 .

[0110] (Effects of the sealing plug 750 according to the fifth modification of the embodiment) (12) As shown in Fig. 17 , the fifth end 756 located at the boundary between the opposed surface 445 and the second outer peripheral surface 447 of the sealing plug 750 is formed in an arc shape and is spaced apart from the second inner peripheral surface 427 of the lid 420. With this configuration, even though the fifth end 756 is formed in an arc shape, it is spaced apart from the second inner peripheral surface 427 of the lid 420, thereby suppressing interference between the sealing plug 750 and the lid 420. As a result, the sealing plug 750 and the lid 420 can be sufficiently attached and joined. By forming the fifth end 756 in an arc shape, the sealing plug 750 is easier to manufacture.

[0111] For example, the fifth end 756 may be formed in a linear shape that is inclined with respect to the stacking direction V when viewed from a direction perpendicular to the stacking direction V. That is, the fifth end 756 may be formed in a notched shape. The direction perpendicular to the stacking direction V is, for example, the short-side direction Y. In this case, the fifth end 756 is configured by forming an inclined surface at the boundary between the opposed surface 445 and the second outer peripheral surface 447. This inclined surface is inclined from the outside toward the inside of the lid 420, moving away from the second inner peripheral surface 427 of the second penetrating portion 420Q. The outside of the lid 420 is the outside of the battery 1. The inside of the lid 420 is the inside of the battery 1.

[0112] (Lid 760 of Modified Example 6 of the Embodiment) The lid 760 of Modified Example 6 of the embodiment will be described with reference to Fig. 18. Fig. 18 is an end view showing a main part of an exterior body 400F of Modified Example 6 of the embodiment.

[0113] 18 , the exterior body 400F includes a lid 760 instead of the lid 420 of the embodiment. The lid 760 includes a first through portion 420P and a second through portion 760Q. The configuration of the second through portion 760Q is the same as the configuration of the second through portion 420Q of the lid 420 of the embodiment, except for the shape of the sixth end portion 766.

[0114] 18 of the sixth modification of the embodiment, the same components as those in the embodiment are denoted by the same reference numerals as those in the embodiment, and the description thereof will be omitted. In FIG. 18 of the sixth modification of the embodiment, the components different from those in the embodiment are denoted by different reference numerals as those in the embodiment.

[0115] In the second penetration portion 760Q of the lid 760, a sixth end 766 located at the boundary between the opposing surface 425 and the second inner circumferential surface 427 is formed in an arc shape. The sixth end 766 is contained within a region defined by an imaginary line extending the opposing surface 425 to the right in Fig. 18 and an imaginary line extending the second inner circumferential surface 427 upward in Fig. 18. The distance between the sixth end 766 of the lid 760 and the second outer circumferential surface 447 of the sealing plug 440 is longer than the distance between the second inner circumferential surface 427 of the lid 760 and the second outer circumferential surface 447 of the sealing plug 440.

[0116] 18 , the sixth end 766 located at the boundary between the opposing surface 425 and the second inner circumferential surface 427 of the lid 760 is formed in an arc shape and is spaced apart from the second outer circumferential surface 447 of the sealing plug 440. This configuration allows for a relatively large gap between the sixth end 766 of the lid 760 and the first end 446 of the sealing plug 440. Because the sixth end 766 of the lid 760 is rounded in an arc shape, there is a relatively large margin for positioning error with the first end 446 and the second outer circumferential surface 447 of the sealing plug 440. Therefore, even if the sealing plug 440 and the lid 760 are tilted relative to each other when the sealing plug 440 and the lid 760 are attached, interference between the sealing plug 440 and the sixth end 766 of the lid 760 can be suppressed. Furthermore, since the sixth end 766 of the lid 760 is rounded in an arc shape, even if the sealing plug 440 and the lid 760 are tilted relative to each other, interference between the opposed surface 445 of the sealing plug 440 and the sixth end 766 of the lid 760 can be suppressed. As a result, the sealing plug 440 and the lid 760 can be sufficiently attached and joined.

[0117] The sixth end 766 may be formed, for example, in a linear shape that is inclined with respect to the stacking direction V when viewed from a direction perpendicular to the stacking direction V. That is, the sixth end 766 may be formed in a notched shape. The direction perpendicular to the stacking direction V is, for example, the short-side direction Y. In this case, the sixth end 766 is configured by forming an inclined surface at the boundary between the opposing surface 425 and the second inner peripheral surface 427. This inclined surface is inclined from the outside toward the inside of the lid 760 so as to approach the second outer peripheral surface 447 of the second insertion portion 440Q. The outside of the lid 760 is the outside of the battery 1. The inside of the lid 760 is the inside of the battery 1.

[0118] (Sealing plug 770 of modified example 7 of embodiment) A sealing plug 770 of modified example 7 of the embodiment will be described with reference to Fig. 19. Fig. 19 is an end view showing a main part of an exterior body 400G of modified example 7 of the embodiment.

[0119] 19, the exterior body 400G includes a sealing plug 770 instead of the sealing plug 440 of the embodiment. The sealing plug 770 includes a base portion 770R in addition to a first insertion portion 440P and a second insertion portion 440Q.

[0120] 19 of the seventh modified embodiment of the embodiment, the same components as those in the embodiment are denoted by the same reference numerals as those in the embodiment, and the description thereof will be omitted. In FIG. 19 of the seventh modified embodiment of the embodiment, the components different from those in the embodiment are denoted by different reference numerals as those in the embodiment.

[0121] In the sealing plug 770, the base 770R corresponds to a fillet weld joint, and the first insertion portion 440P corresponds to a butt weld joint. That is, the base 770R corresponds to a lap fillet weld joint. The base 770R is connected to the first insertion portion 440P from the outside of the lid 420 along the stacking direction V. The base 770R is formed in a cylindrical shape, for example. The base 770R has a larger diameter than the first insertion portion 440P. The central axis of the base 770R coincides with the central axis of the first insertion portion 440P. The base 770R includes an outer surface 771, an outer peripheral surface 772, and an abutment surface 773. The outer surface 771 is located on the outside of the battery 1 at the base 770R and is formed in a circular shape. The abutment surface 773 faces the outer surface 771 in the stacking direction V and is formed in an annular shape. The contact surface 773 is in surface contact with the outer surface 421 of the lid 420. The base portion 770R is integrally molded with the first insertion portion 440P and the second insertion portion 440Q.

[0122] (Manufacturing Method of Battery 1 of Modified Example 7 of the Embodiment) The manufacturing method of battery 1 of Modified Example 7 of the embodiment is characterized only by the attachment and joining of sealing plug 770 and lid 420. Therefore, in the manufacturing method of battery 1 of Modified Example 7 of the embodiment, only the attachment and joining of sealing plug 770 and lid 420 will be described with reference to Fig. 20. Fig. 20 is an end view showing the attachment and joining of sealing plug 770 and lid 420 in the manufacturing method of battery 1 of Modified Example 7 of the embodiment.

[0123] The manufacturing method of the battery 1 of the seventh modified embodiment includes a first step and a second step, similar to the manufacturing method of the battery 1 of the embodiment. In the first step, the lid 420 and the sealing plug 770 are attached by bringing the opposing surface 425 of the lid 420 and the opposed surface 445 of the sealing plug 770 into contact with each other along the stacking direction V, with the opposing surface 425 of the lid 420 and the opposed surface 445 of the sealing plug 770 facing each other in the stacking direction V. In the second step, after the first step, the lid 420 and the sealing plug 770 are welded together.

[0124] The first step of the seventh modified embodiment includes the following in addition to the first step of the seventh embodiment. In the first step, the outer surface 421 of the lid 420 and the abutment surface 773 of the sealing stopper 770 are opposed to each other in the stacking direction V, and the sealing stopper 770 is brought close to the lid 420 along the stacking direction V to attach the sealing stopper 770 to the lid 420. In the manufacturing method of the battery 1 of the embodiment, it was explained that the first insertion portion 440P and the second insertion portion 440Q of the sealing stopper 440 are attached to the lid 420 without tilting or lifting relative to the lid 420. Therefore, the abutment surface 773 of the base 770R makes sufficient surface contact with the outer surface 421 of the lid 420.

[0125] In a second step of the seventh modified embodiment, the sealing plug 770 and the lid 420 are welded. In the seventh modified embodiment, the sealing plug 770 and the lid 420 are laser welded, for example. As shown in Fig. 20 , a weld W2 is formed between the lower end of the outer peripheral surface 772 of the sealing plug 770 and the outer surface 421 of the lid 420. The weld W2 is formed in an annular shape along the base 770R of the sealing plug 770.

[0126] (Effects of the sealing plug 770 and the manufacturing method of the sealing plug 770 according to the seventh modified example of the embodiment) (14) As shown in FIG. 19 , the sealing plug 770 includes a base portion 770R that is continuous with the first insertion portion 440P from the outside of the lid 420 along the stacking direction V. The base portion 770R is joined to the outer surface 421 located on the outside of the lid 420 along the stacking direction V. In this configuration, in order to join the base portion 770R to the lid 420, it is a prerequisite that the first insertion portion 440P and the second insertion portion 440Q of the sealing plug 770 are not tilted or raised relative to the lid 420. If the first insertion portion 440P and the second insertion portion 440Q of the sealing plug 770 are tilted or raised relative to the lid 420, the abutment surface 773 of the base portion 770R cannot be brought into surface contact with the outer surface 421 of the lid 420. In this regard, in the embodiment, it has been described that the first insertion portion 440P and the second insertion portion 440Q of the sealing plug 440 are attached to the lid 420 without tilting or floating relative to the lid 420. Therefore, in the seventh modification of the embodiment, the base portion 770R of the sealing plug 770 can be joined to the lid 420 with sufficient surface contact.

[0127] (Sealing plug 780 of modified example 8 of embodiment) A sealing plug 780 of modified example 8 of the embodiment will be described with reference to Fig. 21. Fig. 21 is an end view showing a main part of an exterior body 400H of modified example 8 of the embodiment.

[0128] (Configuration of sealing plug 780 in modification 8 of embodiment) As shown in FIG. 21 , a recess 780x is formed on the exterior body 400H outside the battery 1. The sealing plug 780 includes a first insertion portion 780P and a second insertion portion 780Q. The first insertion portion 780P has the same configuration as the first insertion portion 440P of the sealing plug 440 of the embodiment, except for the recess 780x. The second insertion portion 780Q has the same configuration as the second insertion portion 440Q of the sealing plug 440 of the embodiment, except for the recess 780x and curved end portion.

[0129] 21 of the eighth modified embodiment of the embodiment, the same components as those in the embodiment are denoted by the same reference numerals as those in the embodiment, and the description thereof will be omitted. In FIG. 21 of the eighth modified embodiment of the embodiment, the components different from those in the embodiment are denoted by different reference numerals as those in the embodiment.

[0130] The sealing plug 780 is formed by press-molding a flat metal plate in the stacking direction V, thereby forming a first insertion portion 780P and a second insertion portion 780Q. A recess 780x is formed on the outside of the battery 1 by press-molding the sealing plug 780. The sealing plug 780 has a uniform thickness in the longitudinal direction X and lateral direction Y of the battery 1, which intersect with the stacking direction V, except for the portion near the first outer peripheral surface 443. The sealing plug 780 may have different thicknesses in the longitudinal direction X and lateral direction Y of the battery 1, which intersect with the stacking direction V. The first end 786 and the end 788 of the second insertion portion 780Q are each formed into an arc shape by press-molding.

[0131] (Effect of sealing plug 780 of variant example 8 of embodiment) (17) As shown in Figure 21, the sealing plug 780 is formed by press-molding a flat metal plate in the stacking direction V, thereby forming a first insertion portion 780P and a second insertion portion 780Q.

[0132] (19) In manufacturing the battery 1, a sealing plug 780 press-molded in the stacking direction V is used. In manufacturing the battery 1, a step of forming the sealing plug 780 by press-molding a flat metal plate in the stacking direction V may be included.

[0133] This configuration facilitates the manufacturing of the sealing plug 780. In particular, this configuration facilitates mass production of the sealing plug 780. Meanwhile, the thickness of the sealing plug 780 in the stacking direction V is thinner than that of the sealing plug 440 of the embodiment. Therefore, when the sealing plug 780 is attached to the lid 420, it is likely to deform along a direction intersecting the stacking direction V. However, like the sealing plug 440 of the embodiment, the sealing plug 780 can be prevented from being attached to the lid 420 in a state where it is partially raised relative to the lid 420. That is, the sealing plug 780 can be prevented from being attached to the lid 420 in a state where it is tilted relative to the lid 420. Furthermore, the sealing plug 780 can be prevented from being attached to the lid 420 in a state where it is entirely raised relative to the lid 420. Furthermore, the sealing plug 780 can be prevented from being attached to the lid 420 in a state where it is distorted or bent relative to the lid 420. As a result, when the sealing plug 780 is attached to the lid 420, deformation along a direction intersecting the stacking direction V can be suppressed. Therefore, the sealing plug 780 and the lid 420 can be sufficiently joined by, for example, welding.

[0134] The configuration of the sealing plug 780 of the eighth modified embodiment can also be applied to the sealing plugs of the first to seventh modified embodiments.

[0135] Other Embodiments The battery of the present invention is not limited to the configuration of the battery described in the embodiments, and can be configured appropriately based on the content described in the claims.

[0136] The embodiments are described in detail or simply to clearly explain the present invention, and do not necessarily include all of the configurations described, or may include configurations not shown. Furthermore, some of the configurations of the embodiments may be deleted, replaced with configurations of other embodiments, or combined. The sealing plug may have a configuration that combines two or more of the configurations of the embodiment and Modifications 1 to 8 of the embodiment.

[0137] (Best Mode Sealing Plug 810 and Lid 760 for Other Embodiments) FIG. 22 shows the main parts of an exterior body 400J configured in the best mode including the configurations of the embodiment and modified examples 1 to 8 of the embodiment.

[0138] As shown in Fig. 22 , the exterior body 400J has a configuration that combines all of the embodiment and the first to eighth modifications of the embodiment. That is, the configuration of the exterior body 400J is a best mode configuration that includes all of the embodiment and the first to eighth modifications of the embodiment. The exterior body 400J includes a lid 760 and a sealing plug 810. The lid 760 includes a first penetration portion 420P and a second penetration portion 760Q. The sealing plug 810 includes a first insertion portion 810P, a second insertion portion 810Q, and a base portion 810R.

[0139] (Sealing plug 820 and lid 420 with relatively eccentric central axes for other embodiments) Figure 23 shows the main parts of an outer casing 400K in which the sealing plug 820 and lid 420 are eccentric, which can be applied to the configurations of the embodiment and embodiment variants 1 to 8.

[0140] As shown in FIG. 23 , the exterior body 400K includes a sealing plug 820 instead of the sealing plug 440 of the embodiment. The sealing plug 820 includes a first insertion portion 440P and a second insertion portion 820Q. The configuration of the second insertion portion 820Q is the same as the configuration of the second insertion portion 440Q of the sealing plug 440 of the embodiment, except for its relative positional relationship with the first insertion portion 440P. The central axis C1 of the liquid injection hole 420c of the lid 420 and the central axis C2 of the second insertion portion 820Q of the sealing plug 820 are eccentric to each other. The central axis C1 is the central axis of the first through portion 420P and the second through portion 420Q of the lid 420. The central axis C1 is also the central axis of the first insertion portion 440P of the sealing plug 820. That is, in the sealing plug 820, the central axis C1 of the first insertion portion 440P and the central axis C2 of the second insertion portion 820Q are relatively spaced apart. Therefore, as an example, the length L1a of the gap S1a on the left side (one end side) of FIG. 23 is shorter than the length L1b of the gap S1b on the right side (the other end side) of FIG.

[0141] As shown in FIG. 23 , the central axis C1 of the first insertion portion 440P of the sealing plug 820 coincides with the central axis of the liquid inlet 420c of the lid 420. The central axis C1 of the first insertion portion 440P of the sealing plug 820 may also be eccentric from the central axis of the liquid inlet 420c of the lid 420. In this case, the first insertion portion 440P and the second insertion portion 820Q may be eccentric from the central axis of the liquid inlet 420c at the same or different positions. The central axis of the first through portion 420P of the liquid inlet 420c of the lid 420 and the central axis of the second through portion 420Q of the liquid inlet 420c of the lid 420 may be spaced apart.

[0142] The shape of the sealing plug and the shape of the liquid inlet of the lid (container) can be various. That is, the central axis of the sealing plug and the central axis of the liquid inlet of the lid may be intentionally misaligned. Furthermore, the central axis of the sealing plug and the central axis of the liquid inlet of the lid may be misaligned due to manufacturing errors. In such cases, the gap between the second outer peripheral surface of the sealing plug and the second inner peripheral surface of the liquid inlet has relatively narrow and relatively wide portions along 360 degrees in the circumferential direction of the liquid inlet. For example, a relatively wide gap is likely to occur on the other end side, 180 degrees circumferentially opposite the relatively narrow gap on one end side, between the outer peripheral surface of the sealing plug and the inner peripheral surface of the liquid inlet. The gap on the one end side is, for example, gap S1a shown in FIG. 23 . The gap on the other end side is, for example, gap S1b shown in FIG. 23 . In this way, even if the central axis of the sealing plug and the central axis of the liquid injection hole are misaligned, gap S1a and gap S12 are relatively wider than the adjacent gap S2 along the stacking direction V over 360 degrees around the circumferential direction of the sealing plug.

[0143] The battery of the present invention is not limited to a configuration in which the sealing plug is inserted into the lid and joined. The battery of the present invention may also be configured in which the sealing plug is inserted into the container and joined. In this configuration, the container and the lid correspond to the housing. The container has an injection hole for inserting the sealing plug.

[0144] The battery of the present invention is not limited to lithium-ion batteries. The battery of the present invention can be applied to, for example, nickel-metal hydride batteries and lead-acid batteries. The battery of the present invention is not limited to secondary batteries. The battery of the present invention can be applied to primary batteries. The charge / discharge body of the battery of the present invention is not limited to a wound type charge / discharge body in which a positive electrode, a separator, and a negative electrode, each formed in a long shape, are bundled and wound. The charge / discharge body of the battery of the present invention can also be a stacked type in which multiple rectangular positive electrodes, separators, and negative electrodes are alternately stacked on top of each other. The charge / discharge body of the battery of the present invention can also be a stacked type in which multiple relatively short positive electrodes and multiple negative electrodes are alternately arranged facing each other with the separator interposed between them, around a single long separator. In such a charge / discharge body, the separator is folded and stacked, so that the positive electrode and the negative electrode face each other with the separator interposed between them. The battery of the present invention is not limited to a configuration in which one charge / discharge body is provided. The battery of the present invention can be applied to a configuration in which two or more charge / discharge bodies are provided. The battery of the present invention is not limited to a configuration in which the charge / discharge body is sealed by a container and a lid. The battery of the present invention can be applied to a configuration in which the charge / discharge element is sealed with a laminate film.

[0145] REFERENCE SIGNS LIST 1 Battery, 100 Charge / discharge body, 110 Positive electrode, 120 Negative electrode, 130 Separator, 140 Electrolyte, 200 Current collector, 210 Positive electrode current collector, 220 Negative electrode current collector, 300 Electrode terminal, 310 Positive electrode terminal, 320 Negative electrode terminal, 400, 400A, 400B, 400C, 400D, 400E, 400F, 400G, 400H, 400J, 400K Outer body, 410 Container (housing), 420 Lid (housing), 420a Positive electrode side insertion hole, 420b Negative electrode side insertion hole, 420c Liquid injection hole, 420P First penetration portion, 420Q Second penetration portion, 421 Outer surface, 422 End, 423 First inner circumferential surface, 424 End, 425 Opposing surface, 426 End (second end), 427 Second inner circumferential surface, 428 End, 429 Inner surface, 430 Split valve, 440 Sealing plug, 440P First insertion part, 440Q Second insertion part, 441 Outer surface, 442 End, 443 First outer circumferential surface, 444 End, 445 Opposed surface, 446 End (first end), 447 Second outer circumferential surface, 448 End, 449 Inner surface, 500 Insulator, 510 Insulating cover, 520 Positive electrode side insulating plate, 530 Negative electrode side insulating plate, 600 Sealing body, 610 Positive electrode side gasket, 620 Negative electrode side gasket 710 sealing plug, 710Q second insertion portion, 717 second outer peripheral surface, 720 sealing plug, 720P first insertion portion, 723 first outer peripheral surface, 730 sealing plug, 730Q second insertion portion, 738 end portion (third end portion), 740 sealing plug, 740P first insertion portion, 744 end portion (fourth end portion), 750 sealing plug, 750Q second insertion portion, 756 end portion (fifth end portion), 760 lid, 760Q second penetration portion, 766 end portion (sixth end portion), 770 sealing plug, 770R base portion, 771 outer surface, 772 outer peripheral surface, 773 abutment surface, 780 sealing plug, 780P first insertion portion, 780Q second insertion portion, 780x recess, 786 end (first end), 788 end, 810 sealing plug, 810P first insertion portion, 810Q second insertion portion, 810R base portion, 820 sealing plug,820Q second insertion portion, C1 central axis (of first insertion portion 440P of sealing plug 820 and liquid injection hole 420c of lid 420), C2 central axis (of second insertion portion 820Q of sealing plug 820), S1 gap (between second inner peripheral surface 427 of lid 420 and second outer peripheral surface 447 of sealing plug 440), S1a gap (between second inner peripheral surface 427 of lid 420 and one end side of second outer peripheral surface 447 of sealing plug 820), S1b gap (between second inner peripheral surface 427 of lid 420 and the other end side of second outer peripheral surface 447 of sealing plug 820), S2 gap between first inner peripheral surface 423 of lid 420 and first outer peripheral surface 443 of sealing plug 440, L1, L1a, L1b length (of gap S1), L2 length (of gap S2), W1 Welded portion, W2 welded portion, V stacking direction (of sealing plug 440 etc. and lid 420 etc.), X longitudinal direction (of battery 1), Y lateral direction (of battery 1), Z height direction (of battery 1).

Claims

1. A device comprising: a charge / discharge body containing an electrolyte; a container that contains the charge / discharge body and includes an injection hole for pouring the electrolyte; and a sealing plug that is inserted into the injection hole and is laminated and joined to the container, wherein the injection hole of the container includes: a first penetration portion that penetrates along a stacking direction with the sealing plug and faces the outside of the container; and a second penetration portion that penetrates along the stacking direction, faces the inside of the container, is connected to the first penetration portion along the stacking direction, and has a smaller opening than the first penetration portion, wherein the first penetration portion includes: a first inner circumferential surface that is aligned with the stacking direction; and an opposing surface that intersects with and is adjacent to the first inner circumferential surface and faces the stacking direction, and wherein the second penetration portion includes: a second inner circumferential surface that intersects with and is adjacent to the opposing surface, is located inside the container relative to the first inner circumferential surface, and is aligned with the stacking direction, and wherein the sealing plug includes: a first insertion portion that is inserted into the first penetration portion along the stacking direction; a second insertion portion that is inserted into the second penetrating portion along the stacking direction, is continuous with the first insertion portion along the stacking direction, and has a smaller area facing in the stacking direction than the first insertion portion, wherein the first insertion portion includes: a first outer peripheral surface facing the first inner peripheral surface of the container, and an opposed surface that intersects with and is adjacent to the first outer peripheral surface and faces the opposed surface of the container, wherein the second insertion portion includes: a second outer peripheral surface that intersects with and is adjacent to the opposed surface, is located more inside the container than the first outer peripheral surface, and faces the second inner peripheral surface of the container, and a length of a gap between the second inner peripheral surface of the container and the second outer peripheral surface of the sealing plug is at least partially wider than a length of a gap between the first inner peripheral surface of the container and the first outer peripheral surface of the sealing plug.

2. The battery described in claim 1, wherein the length of the gap between the second inner circumferential surface of the container and the second outer circumferential surface of the sealing plug is wider than the length of the gap between the first inner circumferential surface of the container and the first outer circumferential surface of the sealing plug.

3. The battery described in claim 1, wherein a first end portion located at the boundary between the opposed surface and the second outer peripheral surface of the sealing plug is at least partially separated from a second end portion located at the boundary between the opposed surface and the second inner peripheral surface of the container.

4. The battery of claim 3, wherein said first end is spaced apart from said second end.

5. The battery described in claim 1, wherein the opposed surface of the sealing plug is in partial surface contact with the opposing surface of the container in a region along a direction intersecting the stacking direction from the first inner surface of the container to the second outer surface of the sealing plug.

6. The battery according to claim 1, wherein the second insertion portion of the sealing plug and the second penetration portion of the container are not attached by press-fitting.

7. The battery according to claim 1, wherein the sealing plug and the container are not attached by press fitting.

8. The battery according to claim 1, wherein the second outer peripheral surface of the sealing plug includes a portion that is narrowed in a direction intersecting the stacking direction from the outside to the inside of the container.

9. The battery according to claim 1, wherein the first outer peripheral surface of the sealing plug includes a portion that narrows in a direction intersecting the stacking direction from the outside to the inside of the container.

10. The battery according to claim 1, wherein the second outer peripheral surface of the sealing plug has a third end located inside the container, the third end being formed in an arc shape or a straight line inclined with respect to the stacking direction.

11. The battery according to claim 1, wherein a fourth end portion located at the boundary between the first outer peripheral surface of the sealing plug and the opposed surface is formed in an arc shape or in a straight line shape inclined with respect to the stacking direction.

12. The battery described in claim 1, wherein a fifth end portion located at the boundary between the opposed surface of the sealing plug and the second outer peripheral surface is formed in an arc shape or a straight line inclined with respect to the stacking direction, and is spaced apart from the second inner peripheral surface of the container.

13. The battery described in claim 1, wherein a sixth end portion located at the boundary between the opposing surface of the container and the second inner peripheral surface is formed in an arc shape or a straight line inclined with respect to the stacking direction, and is spaced apart from the second outer peripheral surface of the sealing plug.

14. The battery described in claim 1, wherein the sealing plug includes a base portion that continues from the outside of the container along the stacking direction relative to the first insertion portion, and the base portion is joined along the stacking direction to an outer surface located on the outside of the container.

15. The battery described in claim 1, wherein a minimum value of the length of the gap between the second inner peripheral surface of the container and the second outer peripheral surface of the sealing plug is greater than a maximum value of the length of the gap between the first inner peripheral surface of the container and the first outer peripheral surface of the sealing plug.

16. The battery described in claim 1, wherein, in any cross section of the sealing stopper and the container parallel to the stacking direction including the central axis of the liquid injection hole, the length of the gap between the second outer peripheral surface of the sealing stopper on one end side and the second inner peripheral surface of the container is wider than the length of the gap between the first outer peripheral surface of the sealing stopper on one end side and the first inner peripheral surface of the container, and the length of the gap between the second outer peripheral surface of the sealing stopper on the other end side and the second inner peripheral surface of the container is wider than the length of the gap between the first outer peripheral surface of the sealing stopper on the other end side and the first inner peripheral surface of the container.

17. The battery according to claim 1, wherein the first insertion portion and the second insertion portion are formed by press-molding a flat metal plate in the stacking direction.

18. A method for manufacturing a battery as described in claim 1, comprising: a first step of attaching the container and the sealing plug by bringing the container and the sealing plug closer together along the stacking direction with the opposing surface of the container and the opposed surface of the sealing plug facing each other in the stacking direction; and a second step of welding the container and the sealing plug together after the first step.

19. The method for manufacturing a battery according to claim 18, further comprising a step of forming the sealing plug by using the sealing plug press-molded in the stacking direction, or by press-molding a flat metal plate in the stacking direction.

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