Metal joined body, battery, and method for manufacturing metal joined body

Abstract

This battery is provided with a metal joined body which is obtained by joining a plurality of metal members by means of ultrasonic bonding. The battery is provided with: an electrode group in which an electrode and a separator are stacked upon each other; a current collector plate which is joined to the electrode group; and an outer package which houses the electrode group and an electrolyte that is in a liquid state. The electrode has a current collector foil and an active material layer. The current collector foil, which is a metal member, and a current collector plate (220), which is a metal member, are joined to each other by means of ultrasonic bonding. The current collector plate (220) has a plurality of pressing marks (231) that is formed by ultrasonic bonding, and a laser mark (233) that is formed so as to overlap the plurality of pressing marks (231). The pressing mark (231) and the laser mark (233) are formed on a surface of the current collector plate (220), the surface being on the reverse side from the bonding surface that is bonded to the current collector foil.

Description

Metallic joint, battery, and method for manufacturing metallic joint

[0001] The present invention relates to a metal joined body, a battery, and a method for producing a metal joined body.

[0002] 2. Description of the Related Art Ultrasonic welding is known, in which a plurality of metal members are joined together by placing them one on top of the other on an anvil and vibrating them while applying pressure with a horn (see Patent Document 1).

[0003] JP 2013-004482 A

[0004] In ultrasonic joining, metal powder and burrs may be formed when metal members are pressed by an anvil and a horn. In products using metal joined bodies formed by joining metal members together, there is a demand for suppressing defects caused by metal powder and burrs.

[0005] A metal joined body according to one embodiment of the present invention is a metal joined body formed by ultrasonically joining a plurality of metal members, wherein one of the metal members has a plurality of pressure marks formed by ultrasonically joining and laser marks formed superimposed on the plurality of pressure marks, and the pressure marks and the laser marks are formed on the surface of one of the metal members opposite to the joining surface with the other of the metal members.

[0006] A battery according to one aspect of the present invention is a battery having a metal joined body formed by ultrasonically joining a plurality of metal members, and comprising: an electrode group in which electrodes and separators are stacked on top of each other; a current collector plate joined to the electrode group; and an outer casing that houses the electrode group and the current collector plate, wherein the electrodes have a current collector foil and an active material layer, the current collector plate, which is one of the metal members, and the current collector foil, which is another of the metal members, are joined by ultrasonically joining, and the current collector plate has a plurality of pressure marks formed by ultrasonic joining and laser marks formed superimposed on the plurality of pressure marks, and the pressure marks and the laser marks are formed on the surface of the current collector plate opposite to the surface joined to the current collector foil.

[0007] A method for manufacturing a metal bonded body according to one aspect of the present invention includes an ultrasonic bonding process in which a plurality of metal members are bonded by clamping the metal members between an anvil and a horn and applying ultrasonic vibrations while pressing the metal members, and a residue removal process in which residues generated in the ultrasonic bonding process are removed from an area including a plurality of indentations formed on the metal members by pressing in the ultrasonic bonding process by irradiating the area with a laser.

[0008] According to the present invention, it is possible to suppress the occurrence of defects caused by metal powder and burrs.

[0009] 1 is a perspective view showing a battery 1 according to a first 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; an exploded perspective view showing components around a positive terminal 310 of the battery 1; an exploded perspective view showing components around a split valve 430 and a sealing plug 440 of the battery 1; an exploded perspective view showing components around a negative terminal 320 of the battery 1; a schematic diagram showing an ultrasonic bonding process for the charging / discharging body 100 and a current collector 200; a schematic diagram showing a current collecting part 222 having a plurality of indentations 231 formed by ultrasonic bonding. 13A and 13B are schematic diagrams showing a residue removal step; a schematic diagram showing a current collecting portion 222 having a laser mark 233 formed so as to overlap a laser irradiated region 232; an enlarged view of a portion XIV in FIG. 13A; a side view of a bus bar 900 used in a battery pack 1000 according to a second embodiment; a schematic diagram showing an ultrasonic bonding step of a positive electrode bonding plate 910 and a negative electrode bonding plate 920; a view of the negative electrode bonding plate 920 of the bus bar 900 as viewed from above; a view of the positive electrode bonding plate 910 of the bus bar 900 as viewed from below;

[0010] 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.

[0011] (Configuration of Battery 1 of First Embodiment) The configuration of the battery 1 will be described with reference to FIGS. 1 to 9. FIG.

[0012] FIG. 1 is a perspective view showing a battery 1 according to a first 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 view of the 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 a perspective view showing an exploded view of components around the negative terminal 320 of the battery 1.

[0013] 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.

[0014] The charge / discharge unit 100 charges and discharges electricity. The charge / discharge unit 100 shown in FIGS. 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 stacked in this order: the positive electrode 110, the separator 130, the negative electrode 120, and the separator 130 into a rectangular parallelepiped shape. The charge / discharge unit 100 may be configured by winding or stacking. The charge / discharge unit 100 in which the electrodes (positive electrode 110 and negative electrode 120) and the separator 130 are stacked on top of each other is also called an electrode group.

[0015] The positive electrode (electrode) 110 includes a long positive electrode current collector foil (current collector foil) 111 and positive electrode active material layers (active material layers) 112 bonded to both sides of the positive electrode current collector foil 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 collector foil 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 collector plate 210. The positive electrode active material layer 112 is bonded to the positive electrode current collector foil 111 except for the side 111a. The positive electrode active material layer 112 is bonded to both sides of the positive electrode current collector foil 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 collector foil 111. The positive electrode current collector foil 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).

[0016] The negative electrode (electrode) 120 includes a long negative electrode current collector foil (current collector foil) 121 and negative electrode active material layers (active material layers) 122 bonded to both sides of the negative electrode current collector foil 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 collector foil 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 collector foil 121 faces the side 111a of the positive electrode current collector foil 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 foil 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 foil 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 foil 121. The negative electrode current collector foil 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.

[0017] 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.

[0018] 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.

[0019] The current collector 200 is joined 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 9 includes a positive electrode current collector plate 210 and a negative electrode current collector plate 220.

[0020] As shown in FIG. 4 , the positive electrode current collector 210 electrically connects the positive electrode 110 and the positive electrode terminal 310. As shown in FIG. 7 , the positive electrode current collector 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 by, for example, 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 ultrasonic 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.

[0021] 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. 9 , 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. 9 , 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 ultrasonic bonding. As shown in FIG. 9 , 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.

[0022] The electrode terminal 300 is connected to the current collector 200. The electrode terminal 300 shown in Figures 1 to 4, 7 and 9 includes a positive electrode terminal 310 and a negative electrode terminal 320.

[0023] 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.

[0024] 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. 9 , 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. 9 , and a cylindrical joint portion 323 that protrudes downward from the outer periphery of the insertion portion 322 in FIG. 9 . 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.

[0025] 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 9 includes a container 410, a lid 420, a split valve 430, and a sealing plug 440.

[0026] The container 410 contains the charge / discharge element 100, the current collector 200, etc. The container 410 is made of a rectangular metal can. The container 410 includes an opening 410a that opens along the longitudinal direction X 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.

[0027] 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. 9 , 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 has a liquid injection insertion hole 420c formed as a circular through-hole between the positive electrode side insertion hole 420a and the negative electrode side insertion hole 420b. An insertion portion 440b of a sealing plug 440 is inserted into the liquid injection insertion hole 420c. The lid 420 is welded to the container 410. The lid 420 is made of, for example, aluminum or an aluminum alloy.

[0028] 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.

[0029] The sealing plug 440 seals the liquid injection insertion hole 420c of the lid 420 shown in Fig. 8. The sealing plug 440 is formed in a cylindrical shape. As shown in Fig. 8, the sealing plug 440 includes a head portion 440a having a relatively large outer diameter and an insertion portion 440b that is continuous with the head portion 440a and has a relatively small outer diameter. The head portion 440a of the sealing plug 440 is welded to the lid 420. The insertion portion 440b is inserted into the liquid injection insertion hole 420c. The sealing plug 440 is formed of, for example, aluminum or an aluminum alloy.

[0030] 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 9 includes an insulating cover 510, a positive electrode side insulating plate 520, and a negative electrode side insulating plate 530.

[0031] 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.

[0032] 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 annular edge portion 522 that protrudes from the base 521 in a direction away from the surrounding 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.

[0033] 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 9 , the negative electrode side insulating plate 530 includes a rectangular parallelepiped base portion 531 and an annular edge portion 532 that protrudes from the base 531 in a direction away from the surrounding lid 420. The base portion 221 of the negative electrode current collector plate 220 is accommodated in a space defined by the base portion 531 and the edge portion 532 of the negative electrode side insulating plate 530. A through hole 531 a is formed in the base portion 531. The insertion portion 622 of the negative electrode side gasket 620 is inserted into the through hole 531 a of the base portion 531. The negative electrode side insulating plate 530 is formed, for example, from an insulating resin.

[0034] 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 9 includes a positive electrode side gasket 610 and a negative electrode side gasket 620.

[0035] 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 annular edge portion 613 that surrounds the base 611 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.

[0036] 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. 9 , 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 annular edge portion 623 that surrounds the base 621 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.

[0037] (Manufacturing Method of Battery 1 of First Embodiment) The manufacturing method of battery 1 includes a charge / discharge unit forming step of forming a charge / discharge unit. The steps other than the charge / discharge unit forming step are well known steps, and therefore, description thereof will be omitted. The charge / discharge unit is formed by joining a charge / discharge body 100 and a current collector 200.

[0038] The charge / discharge unit formation process includes a positive electrode-side metal assembly formation process and a negative electrode-side metal assembly formation process. In the positive electrode-side metal assembly formation process, the side portion 111a of the charge / discharge unit 100 is joined to the positive electrode current collector plate 210, thereby forming a positive electrode-side metal assembly in which multiple positive electrode current collector foils 111 and positive electrode current collector plates 210 are joined. The thickness of the positive electrode current collector foil 111 is sufficiently thinner than that of the positive electrode current collector plate 210. In the negative electrode-side metal assembly formation process, the side portion 121a of the charge / discharge unit 100 is joined to the negative electrode current collector plate 220, thereby forming a negative electrode-side metal assembly in which multiple negative electrode current collector foils 121 and negative electrode current collector plates 220 are joined. The thickness of the negative electrode current collector foil 121 is sufficiently thinner than that of the negative electrode current collector plate 220.

[0039] The positive electrode side metal bond formation process includes a positive electrode side ultrasonic bonding process and a positive electrode side residue removal process. In the positive electrode side ultrasonic bonding process, the side portion 111a of the charge / discharge body 100 and the current collecting portion 212 of the positive electrode current collecting plate 210 are bonded by ultrasonic bonding. In the positive electrode side ultrasonic bonding process, metal powder and burrs are generated. The generated metal powder and burrs remain on the positive electrode current collecting plate 210 as residue. In the positive electrode side residue removal process, the residue remaining on the positive electrode current collecting plate 210 is removed by a laser.

[0040] The negative electrode side metal bond formation process includes a negative electrode side ultrasonic bonding process and a negative electrode side residue removal process. In the negative electrode side ultrasonic bonding process, the side portion 121a of the charge / discharge body 100 and the current collecting portion 222 of the negative electrode current collecting plate 220 are bonded by ultrasonic bonding. In the negative electrode side ultrasonic bonding process, metal powder and burrs are generated. The generated metal powder and burrs remain on the negative electrode current collecting plate 220 as residue. In the negative electrode side residue removal process, the residue remaining on the negative electrode current collecting plate 220 is removed by a laser.

[0041] The ultrasonic bonding process and residue removal process for the positive electrode side are the same as those for the negative electrode side. Therefore, the ultrasonic bonding process and residue removal process for the negative electrode side will be described in detail below, and a description of the ultrasonic bonding process and residue removal process for the positive electrode side will be omitted.

[0042] (Ultrasonic Bonding Process) Figure 10 is a schematic diagram showing the ultrasonic bonding process of the charge / discharge body 100 and the current collector 200. As shown in Figure 10, the side portion 121a of the negative electrode current collector foil 121 is bundled into a flat plate. This bundled portion will be referred to as the negative electrode side bundling portion 121b hereinafter. The ultrasonic bonding device 700 includes an ultrasonic horn (hereinafter simply referred to as the horn) 710, which is a vibrating body, an anvil 720, which is a support member arranged opposite the horn 710, and a horn drive unit (not shown) that drives the horn 710.

[0043] The current collecting portion 222 of the negative current collecting plate 220 is placed on the anvil 720. The negative electrode side bundling portion 121b of the negative electrode current collecting foil 121 is placed on the current collecting portion 222. The horn 710 contacts one surface 121c of the negative electrode side bundling portion 121b. The negative electrode side bundling portion 121b and the current collecting portion 222 are clamped between the horn 710 and the anvil 720. The horn 710 is ultrasonically vibrated while pressing against the negative electrode side bundling portion 121b. This removes the oxide film present on the surfaces of the current collecting portion 222 and the negative electrode current collecting foil 121. Furthermore, frictional heat caused by the vibration promotes atomic diffusion, thereby ultrasonically bonding the current collecting portion 222 and the negative electrode side bundling portion 121b together.

[0044] In this way, in the ultrasonic bonding process, the current collecting portion 222 of the negative electrode current collecting plate 220 and the negative electrode side bundling portion 121b of the charging / discharging body 100 are clamped between the anvil 720 and the horn 710 and pressed while applying ultrasonic vibrations, thereby bonding the current collecting portion 222 and the negative electrode side bundling portion 121b.

[0045] The current collecting portion 222 of the negative electrode current collecting plate 220, which is one metal member, and the negative electrode side bundling portion 121b of the negative electrode current collecting foil 121, which is another metal member, are joined by ultrasonic bonding to form a metal joint 229 in which the current collecting portion 222 and the negative electrode side bundling portion 121b are integrated.

[0046] The horn 710 has a rectangular parallelepiped horn body 711 and protrusions 712 that protrude from a facing surface 711a, which is a flat surface of the horn body 711 that faces the anvil 720, toward the anvil 720. Multiple protrusions 712 (three in this example) are provided. The multiple protrusions 712 are arranged in a straight line along the height direction Z of the battery 1 (the longitudinal direction of the negative electrode current collector plate 220).

[0047] The anvil 720 has a rectangular parallelepiped anvil body 721 and a plurality of protrusions 722 that protrude toward the horn 710 from a facing surface 721a, which is a flat surface facing the horn 710. The plurality of protrusions 722 are arranged in an array. The protrusions 722 are formed in a quadrangular pyramid shape with a diamond-shaped base. Note that the shape of the protrusions 722 is not limited to a quadrangular pyramid shape. The protrusions 722 may also be conical, triangular pyramidal, or polygonal pyramidal with a pentagonal or higher-sided base. The protrusions 722 may also be frustum-shaped.

[0048] FIG. 11 is a schematic diagram showing a current collecting part 222 having multiple indentations 231 formed by ultrasonic bonding. The anvil 720 has multiple protrusions (knurls) 722 arranged in an array. Therefore, after the ultrasonic bonding process is completed, as shown in FIG. 11 , multiple indentations (knurls) 231 are formed in an array on the surface of the current collecting part 222 of the negative electrode current collecting plate 220 opposite the bonding surface (interface) with the negative electrode current collecting foil 121. The array refers to a state in which the indentations are arranged in multiple rows and multiple columns according to a predetermined pattern. The indentations 231 are quadrangular pyramidal recesses recessed toward the negative electrode current collecting foil 121. The length Lz of the indentation 231 in the height direction Z of the battery 1 (the length of the diagonal line extending up and down in the illustrated diamond shape) is shorter than the length Lx of the indentation 231 in the longitudinal direction X of the battery 1 (the length of the diagonal line extending left and right in the illustrated diamond shape). The shape of the indentation 231 is determined according to the shape of the protrusion 722 of the anvil 720. The indentation 231 may be a cone, a triangular pyramid, or a polygonal pyramid with a pentagonal or higher-sided base. The indentation 231 may also be a frustum shape.

[0049] The arrangement pattern of the indentations 231 is the same as the arrangement pattern of the protrusions 722 on the anvil 720. Of the multiple indentations 231 arranged in a matrix, the multiple indentations 231 constituting one row are arranged at equal intervals at a first pitch Pxa in the longitudinal direction X of the battery 1 and at a second pitch Pza in the height direction Z of the battery 1. For ease of explanation, the multiple indentations 231 in one row will be referred to as row-unit indentations. The row-unit indentations are arranged at equal intervals at a fourth pitch Pzb in the height direction Z of the battery 1. It can also be said that the row-unit indentations are arranged at equal intervals at a third pitch Pxb in the longitudinal direction X of the battery 1. The third pitch Pxb is equivalent to three times the first pitch Pxa (Pxb = 3 × Pxa). The fourth pitch Pzb is equivalent to three times the second pitch Pza (Pzb = 3 × Pza).

[0050] The arrangement pattern of the protrusions 722 of the anvil 720 and the plurality of indentations 231 is not limited to the example shown in Fig. 11. The arrangement pattern may be a matrix pattern such as a checkerboard pattern or a staggered pattern.

[0051] Once the ultrasonic bonding process is complete, the process proceeds to the residue removal process. Figure 12 is a schematic diagram illustrating the residue removal process. In this process, a laser 801 is irradiated onto an area 232 (hereinafter also referred to as the laser irradiation area) including multiple indentations 231 formed on the current collecting section 222 by the pressure applied during the ultrasonic bonding process. The laser irradiation area 232 (see Figure 11) encompasses all of the indentations (knurled marks) 231. The laser irradiation device 800 irradiates a predetermined irradiation position with the laser 801 for a predetermined period of time, then changes the irradiation position and irradiates the laser 801 again for a predetermined period of time, repeating this process. The laser 801 is irradiated at equal intervals at a pitch PLx in the longitudinal direction X of the battery 1. The laser 801 is also irradiated at equal intervals at a pitch PLz in the height direction Z of the battery 1.

[0052] 12 , when the laser irradiation area 232 is irradiated with a laser (short-pulse laser) 801 for a predetermined period of time, plasma is generated on the surface of the laser irradiation area 232. The impact pressure of the plasma removes the residue 9. The residue 9 includes burrs formed on the edges of the indentation 231 and metal powder adhering to the recesses of the indentation 231. The burrs are peeled off from the current collecting part 222 by the impact pressure of the plasma. The metal powder adhering to the recesses of the indentation 231 is blown from the inside to the outside of the recesses of the indentation 231 by the impact pressure of the plasma.

[0053] Within the plane of the laser irradiation area 232, the spot light 802 (see FIG. 14 ) of the laser 801 irradiating the laser irradiation area 232 is smaller than the indentation 231. The spot light 802 of the laser 801 refers to the circular light irradiated onto the laser irradiation area 232, and hereinafter, the diameter of the spot light 802 is also referred to as the spot diameter DL (see FIG. 14 ). The spot diameter DL of the laser 801 is smaller than the length Lx of the indentation 231 along the longitudinal direction X of the battery 1, and is also smaller than the length Lz of the indentation 231 along the height direction Z of the battery 1. In other words, the size of the spot light 802 of the laser 801 is such that it fits completely within the area surrounded by the outer edge of the indentation 231. This allows for appropriate removal of metal powder adhering to the recess of the indentation 231, preventing metal powder from remaining in the recess. The spot diameter DL of the laser 801 is preferably, for example, half or less of the length Lz of the indentation mark 231 , and more preferably, one-tenth or less of the length Lz of the indentation mark 231 .

[0054] In the residue removal process, the laser irradiation area 232 is irradiated with a laser 801, and a gas (e.g., air) is blown onto the laser irradiation area 232. The gas is blown toward the irradiation position of the laser 801, as shown by arrow F1 in Fig. 12 . The gas blown onto the laser irradiation area 232 is sucked into a dust collector (not shown) together with the residue 9, as shown by arrow F2 in Fig. 12 . This prevents the residue 9 blown away by the laser 801 from adhering to the current collecting part 222 again.

[0055] Here, if the output of the laser irradiation device 800 is too high, the surface of the current collecting part 222 may melt or evaporate, potentially damaging the current collecting part 222. For this reason, in the residue removal step, it is preferable to irradiate the current collecting part 222 with the laser 801 at a position where the distance from the condenser lens of the laser irradiation device 800 to the current collecting part 222 is shorter or longer than the focal length of the condenser lens. By intentionally shifting the focal length, it is possible to appropriately remove the residue 9 while suppressing damage to the current collecting part 222.

[0056] FIG. 13 is a schematic diagram of the current collecting part 222 having a laser mark 233 formed so as to overlap the laser irradiation region 232. FIG. 14 is an enlarged view showing an enlarged view of part XIV in FIG. 13 . By irradiating the laser irradiation region 232 with a laser 801, a laser mark 233 is formed so as to overlap the multiple press marks 231 on the surface of the current collecting part 222 of the negative electrode current collecting plate 220 opposite the bonding surface (interface) with the negative electrode current collecting foil 121. The surface roughness of the laser mark 233 is greater than the surface roughness of the surface of the current collecting part 222 around the laser irradiation region 232. The surface roughness of the laser mark 233 is greater than the surface roughness of the surface of the laser irradiation region 232 before irradiation with the laser 801. Furthermore, the surface color of the laser mark 233 is different from the surface color of the current collecting part 222 around the laser irradiation region 232. The surface color of the laser mark 233 differs from the surface color of the laser irradiated area 232 before irradiation with the laser 801. The appearance of the laser mark 233 varies depending on the output of the laser 801. The laser mark 233 may have a microporous structure due to melting and evaporation of metal caused by irradiation with the laser 801. At the very least, the surface appearance of the laser mark 233 differs from the surface appearance around the laser irradiated area 232, and is also visually distinguishable.

[0057] In this embodiment, the purpose of irradiating the current collecting part 222 with the laser 801 is to remove the residue 9, so the molten zone remains near the surface of the current collecting part 222. For example, in laser welding, a molten zone is formed from the front surface to the back surface of the member that is the target of laser irradiation. In contrast, in this embodiment, when the current collecting part 222, which is the member that is the target of laser irradiation with the laser 801, is viewed in the thickness direction, a molten zone is formed in the portion of the current collecting part 222 that is close to the laser irradiated surface, but no molten zone is formed in the portion of the current collecting part 222 that is away from the laser irradiated surface. In other words, when the current collecting part 222 is viewed in the thickness direction, the portion of the current collecting part 222 that is away from the laser irradiated surface becomes a non-molten zone. In other words, no molten region or laser mark is formed on the surface of the current collecting part 222 opposite to the surface on which the laser mark 233 is formed. Furthermore, the laser 801 does not penetrate the current collecting part 222. Therefore, no melted area or laser mark is formed by the laser 801 on the negative electrode side bundling portion 121 b of the negative electrode current collector foil 121 joined to the current collector portion 222 of the negative electrode current collector plate 220 .

[0058] As shown in FIG. 14 , the laser mark 233 is composed of multiple laser spot marks 233a. The laser spot marks 233a are formed by irradiation with a short-pulse laser. Within the surface of the laser irradiation area 232, the laser spot marks 233a are smaller than the indentation marks 231. The laser 801 is irradiated at a pitch PLx in the longitudinal direction X of the battery 1. In other words, the short-pulse laser is irradiated while scanning from one end of the laser irradiation area 232 to the other. After scanning to the other end of the laser irradiation area 232 is completed, the laser irradiation position shifts by a pitch PLz in the height direction Z of the battery 1. The short-pulse laser is then irradiated while scanning from one end of the laser irradiation area 232 to the other along the longitudinal direction X of the battery 1. In this way, the short-pulse laser is irradiated while scanning in the longitudinal direction X and height direction Z of the battery 1. The pitches PLx and PLz are set so that adjacent laser spot marks 233a overlap in the longitudinal direction X and height direction Z of the battery 1, and so that no gaps are formed between adjacent laser spot marks 233a.

[0059] The laser spot marks 233a are formed in an array. In the example shown in Fig. 14, the laser spot marks 233a are formed in a checkerboard (grid) pattern, but the arrangement pattern of the laser spot marks 233a is not limited to this. The arrangement pattern of the laser spot marks 233a may be any array pattern in which the laser spot marks 233a are arranged in multiple rows and multiple columns according to a predetermined pattern, such as a staggered pattern.

[0060] (Advantages of Battery 1 of First Embodiment) The advantages of battery 1 of the first embodiment will be described.

[0061] The battery 1 includes a metal joined body (e.g., a negative electrode metal joined body 229) formed by ultrasonically joining multiple metal members (e.g., a negative electrode current collector 220, a negative electrode current collector foil 121). The battery 1 includes a charge / discharge body (electrode group) 100 in which electrodes (a positive electrode 110, a negative electrode 120) and a separator 130 are stacked one on top of the other, current collector plates (a positive electrode current collector 210, a negative electrode current collector 220) joined to the charge / discharge body 100, and an exterior body 400 that houses the charge / discharge body 100 and the current collector plates. The electrodes (a positive electrode 110, a negative electrode 120) include current collector foils (a positive electrode current collector foil 111, a negative electrode current collector foil 121) and active material layers (a positive electrode active material layer 112, a negative electrode active material layer 122). A positive current collector plate 210, which is one metal member, and a positive current collector foil 111, which is another metal member, are joined by ultrasonic bonding to form a metal joined body on the positive electrode side. A negative current collector plate 220, which is one metal member, and a negative current collector foil 121, which is another metal member, are joined by ultrasonic bonding to form a metal joined body 229 on the negative electrode side. As shown in Fig. 13 , the negative current collector plate 220 has a plurality of indentations 231 formed by ultrasonic bonding and laser marks 233 formed superimposed on the plurality of indentations 231. Although not shown, the positive current collector plate 210 similarly has a plurality of indentations 231 formed by ultrasonic bonding and laser marks 233 formed superimposed on the plurality of indentations 231. The pressure marks 231 and the laser marks 233 are formed on the surfaces of the current collector plates (positive current collector plate 210, negative current collector plate 220) opposite to the bonding surfaces with the current collector foils (positive current collector foil 111, negative current collector foil 121). With this configuration, metal powder and burrs are removed by the laser 801. This prevents the metal powder and burrs generated during ultrasonic bonding from being mixed inside the exterior body 400 of the battery 1. As a result, the metal powder and burrs are prevented from damaging the separator 130 of the charge / discharge unit 100, and voltage drop defects can be prevented. Therefore, this embodiment can provide a battery 1 that can suppress defects caused by metal powder and burrs.

[0062] The manufacturing method of battery 1 includes an ultrasonic bonding process (e.g., a negative-electrode-side ultrasonic bonding process for bonding negative electrode current collector plate 220 and negative electrode current collector foil 121) in which multiple metal members are sandwiched between an anvil 720 and a horn 710 and pressed while ultrasonic vibrations are applied to join the multiple metal members. The manufacturing method of battery 1 also includes a residue removal process in which a laser 801 is applied to a laser irradiation region (region) 232 including multiple indentations 231 formed on the metal members (e.g., negative electrode current collector plate 220) by pressing in the ultrasonic bonding process, thereby removing residue 9 generated in the ultrasonic bonding process from the laser irradiation region 232. In the residue removal process, plasma is generated by irradiating laser 801 onto the laser irradiation region 232. The impact pressure of the plasma properly removes residue 9 generated in the ultrasonic bonding process.

[0063] In the residue removal process, a spot light 802 (irradiation light within the surface of the laser irradiation area 232) of the laser 801 irradiated onto the laser irradiation area 232 is smaller than the indentation mark 231. This allows the residue 9 to be removed more easily and appropriately than when the spot light 802 is larger than the indentation mark 231.

[0064] The laser mark 233 is made up of a plurality of laser spot marks 233a. The laser spot marks 233a are smaller than the indentation marks 231. This means that the spot light 802 of the laser 801 is smaller than the indentation marks 231. Therefore, compared to when the spot light 802 of the laser 801 is larger than the indentation marks 231, the charge / discharge unit housed in the exterior body 400 has the residue 9 properly removed. As a result, problems caused by the residue 9 can be more effectively prevented.

[0065] In the residue removal step, a laser 801 is irradiated onto a metal member (e.g., the surface of the current collecting portion 222 of the negative electrode current collecting plate 220) at a position where the distance from the condenser lens of the laser irradiation device 800 to the metal member (e.g., the surface of the current collecting portion 222 of the negative electrode current collecting plate 220) is shorter or longer than the focal length of the condenser lens. By intentionally shifting the focus of the laser 801 during irradiation, the residue 9 can be appropriately removed without damaging the base metal member (e.g., the negative electrode current collecting plate 220) even if the output of the laser 801 is too high.

[0066] In the residue removal step, the laser irradiated region 232 is irradiated with a laser 801, and simultaneously, gas is blown onto the laser irradiated region 232 and the blown gas is sucked in. This prevents the residue 9 blown off from the metal member (e.g., the negative electrode current collector plate 220) by the laser 801 from adhering to the metal member (e.g., the negative electrode current collector plate 220) again.

[0067] Adjacent laser spot marks 233a overlap. For example, the laser irradiation device 800 irradiates the laser 801 so that the spot light 802 of the laser 801 overlaps the laser spot mark 233a formed by the laser irradiation in the previous process. This allows the laser spot marks 233a to overlap. Since the laser 801 is irradiated to the laser irradiation area 232 a sufficient number of times, the residue 9 can be appropriately removed from the entire laser irradiation area 232. Note that forming the overlapping areas of the laser spot marks 233a with a gap therebetween is preferable because it allows the residue 9 to be effectively removed and the number of laser spots to be reduced.

[0068] (Configuration of battery pack 1000 according to second embodiment) The configuration of the battery pack 1000 according to the second embodiment will be described with reference to Fig. 15 to Fig. 18. The same reference symbols are used to designate components that are the same as or equivalent to those described in the first embodiment, and differences will be mainly described.

[0069] FIG. 15 is a side view of a bus bar 900 used in a battery pack 1000 according to the second embodiment. FIG. 16 is a schematic diagram showing the ultrasonic bonding process of a positive electrode bonding plate 910 and a negative electrode bonding plate 920. FIG. 17 is a view of the negative electrode bonding plate 920 of the bus bar 900 as viewed from above. FIG. 18 is a view of the positive electrode bonding plate 910 of the bus bar 900 as viewed from below. The battery pack 1000 includes a plurality of batteries 1, a holding unit (not shown) that holds the plurality of batteries 1, and one or more bus bars 900 that electrically connect the plurality of batteries 1. The holding unit holds the plurality of batteries 1 arranged at predetermined intervals.

[0070] 15 , the bus bar 900 connects the positive electrode terminal 310 of one battery 1 to the negative electrode terminal 320 of another battery 1. The bus bar 900 is a metal bonded body formed by ultrasonically bonding a positive electrode bonding plate 910 that is bonded to the positive electrode terminal 310 and a negative electrode bonding plate 920 that is bonded to the negative electrode terminal 320. The positive electrode bonding plate 910 and the negative electrode bonding plate 920 are formed, for example, by bending flat plate-shaped members.

[0071] The positive electrode bonding plate 910 has a flat base end 911 extending in the short-side direction Y of the battery 1, a flat extension 913 bent 90° from the base end 911 and extending in the height direction Z of the battery 1, and a flat tip end 912 bent 90° from the extension 913 and extending in the short-side direction Y of the battery 1. The positive electrode bonding plate 910 has a crank shape in side view. The base end 911 of the positive electrode bonding plate 910 is bonded to the positive terminal 310. The tip end 912 of the positive electrode bonding plate 910 is bonded to the negative electrode bonding plate 920. The extension 913 connects the base end 911 and the tip end 912.

[0072] The negative electrode contact plate 920 has a flat base end 921 extending in the short-side direction Y of the battery 1, a flat extension portion 923 bent 90° from the base end 921 and extending in the height direction X of the battery 1, and a flat tip end 922 bent 90° from the extension portion 923 and extending in the short-side direction Y of the battery 1. The negative electrode contact plate 920 has a crank shape in side view. The base end 921 of the negative electrode contact plate 920 is joined to the negative terminal 320. The tip end 922 of the negative electrode contact plate 920 is joined to the positive electrode contact plate 910. The extension portion 923 connects the base end 921 and the tip end 922.

[0073] The positive electrode contact plate 910 is made of aluminum or an aluminum alloy, and the negative electrode contact plate 920 is made of copper or a copper alloy.

[0074] (Method of Manufacturing Bus Bar 900 of Second Embodiment) The method of manufacturing the bus bar 900 includes an ultrasonic bonding step and a residue removing step.

[0075] 16, in the ultrasonic bonding process, the positive electrode bonding plate 910 and the negative electrode bonding plate 920 are ultrasonically bonded by an ultrasonic bonding device 700B. The ultrasonic bonding device 700B has the same configuration as the ultrasonic bonding device 700 described in the first embodiment, but the configurations of the protrusion 712B of the horn 710B and the protrusion 722C of the anvil 720C are different from those described in the first embodiment.

[0076] Protrusions 712B of horn 710B and protrusions 722C of anvil 720C are pyramidal in shape with a square base. Protrusions 712B are larger than protrusions 722C. The multiple protrusions 712B of horn 710B are arranged in a staggered pattern. The multiple protrusions 722C of anvil 720C are arranged in a grid pattern (a lattice pattern).

[0077] In the ultrasonic bonding process, the positive electrode bonding plate 910 and the negative electrode bonding plate 920 are sandwiched between the anvil 720 and the horn 710 and pressed while ultrasonic vibrations are applied, thereby bonding the positive electrode bonding plate 910 and the negative electrode bonding plate 920 together.

[0078] In the ultrasonic bonding process, the metal member that contacts the anvil 720 may be the positive electrode bonding plate 910 or the negative electrode bonding plate 920. In this embodiment, an example will be described in which ultrasonic bonding is performed in a state in which the positive electrode bonding plate 910 is in contact with the anvil 720 and the negative electrode bonding plate 920 is in contact with the horn 710, thereby bonding the positive electrode bonding plate 910 and the negative electrode bonding plate 920 together.

[0079] A plurality of press marks 231B are formed on the surface of the negative electrode contact plate 920 opposite to the surface to be joined with the positive electrode contact plate 910 by pressing with a plurality of protrusions 712B of the horn 710B. The plurality of press marks 231B are formed in a checkerboard pattern (grid pattern) as shown in Fig. 17 . A plurality of press marks 231C are formed on the surface of the positive electrode contact plate 910 opposite to the surface to be joined with the negative electrode contact plate 920 by pressing with a plurality of protrusions 722C of the anvil 720C. The plurality of press marks 231C are formed in a staggered pattern as shown in Fig. 18 .

[0080] (Residue Removal Process) The residue removal process includes a residue removal process for the positive electrode bonding plate 910 and a residue removal process for the negative electrode bonding plate 920. In the residue removal process for the positive electrode bonding plate 910, as shown in FIG. 18 , a laser 801 is irradiated onto a laser irradiation area 232C including a plurality of pressure marks 231C formed on the positive electrode bonding plate 910 by pressing during the ultrasonic bonding process, thereby removing the residue 9 generated during the ultrasonic bonding process from the laser irradiation area 232C. A laser mark 233C is formed on the positive electrode bonding plate 910 so as to overlap the plurality of pressure marks 231C. When the tip portion 912 of the positive electrode bonding plate 910 is viewed in the thickness direction, a portion of the positive electrode bonding plate 910 away from the laser-irradiated surface is a non-melted portion. In other words, neither a melted region nor a laser mark is formed on the surface of the positive electrode bonding plate 910 opposite to the surface on which the laser mark 233C is formed. 17 , in the residue removal process for the negative electrode bonding plate 920, a laser 801 is irradiated onto a laser irradiation area 232B including a plurality of pressure marks 231B formed on the negative electrode bonding plate 920 by pressing during the ultrasonic bonding process, thereby removing the residue 9 generated during the ultrasonic bonding process from the laser irradiation area 232B. Laser marks 233B are formed on the negative electrode bonding plate 920 so as to overlap the plurality of pressure marks 231B. When the tip portion 922 of the negative electrode bonding plate 920 is viewed in the thickness direction, a portion of the negative electrode bonding plate 920 away from the laser-irradiated surface is a non-melted portion. That is, neither a melted region nor a laser mark is formed on the surface of the negative electrode bonding plate 920 opposite to the surface on which the laser marks 233B are formed.

[0081] (Advantages of the Battery Pack 1000 of the Second Embodiment) The advantages of the battery pack 1000 of the second embodiment will be described.

[0082] The battery pack 1000 electrically connects multiple batteries 1. Each battery 1 has a positive electrode terminal 310 and a negative electrode terminal 320. The positive electrode terminal 310 of one battery 1 and the negative electrode terminal 320 of another battery 1 are connected by a bus bar 900. The bus bar 900 is formed by ultrasonically bonding multiple metal members (a positive electrode bonding plate 910 and a negative electrode bonding plate 920). The positive electrode bonding plate 910 has multiple press marks 231C formed by ultrasonic bonding and laser marks 233C formed superimposed on the multiple press marks 231C. The press marks 231C and the laser marks 233C are formed on the surface of the positive electrode bonding plate 910 opposite the bonding surface with the negative electrode bonding plate 920. The negative electrode bonding plate 920 has multiple press marks 231B formed by ultrasonic bonding and laser marks 233B formed superimposed on the multiple press marks 231B. The press marks 231B and the laser marks 233B are formed on the surface of the negative electrode bonding plate 920 opposite to the bonding surface with the positive electrode bonding plate 910. With this configuration, residues 9 such as metal powder and burrs generated by ultrasonic bonding are removed by the laser. Therefore, it is possible to prevent defects in the battery pack 1000 caused by the metal powder and burrs.

[0083] (Battery and battery assembly of other embodiments) The battery and battery assembly of the present invention are not limited to the configuration of the battery 1 and battery assembly 1000 described in the embodiments, and can be configured as appropriate based on the content described in the claims.

[0084] The embodiments are described in detail or simply to make the present invention easier to understand, and do not necessarily include all of the components described, or may include components not shown. Also, some of the components of the embodiments may be deleted, replaced with components of other embodiments, or combined with components of other embodiments.

[0085] In the first embodiment, an example was described in which the spot light 802 of the laser 801 and the laser spot mark 233a on the surface of the current collecting section 222 (the surface perpendicular to the short-side direction Y of the battery 1) are smaller than the indentation mark 231. However, the spot light 802 of the laser 801 and the laser spot mark 233 may be equal to or larger than the indentation mark 231 on the surface of the current collecting section 222 (the surface perpendicular to the short-side direction Y of the battery 1).

[0086] In the first embodiment, an example has been described in which adjacent laser spot marks 233a overlap each other. However, adjacent laser spot marks 233a do not have to overlap each other. In other words, adjacent laser spot marks 233a may be formed with a gap between them. It is sufficient that at least the laser spot marks 233a are formed overlapping the pressure marks 231. This makes it possible to remove residues 9 such as metal powder and burrs, and also reduces the number of laser spots.

[0087] In the first embodiment, an example has been described in which the laser 801 is irradiated onto the current collecting part 222 at a position where the distance from the condenser lens of the laser irradiation device 800 to the current collecting part 222 is shorter or longer than the focal length of the condenser lens in the residue removal process. However, the distance from the laser irradiation device 800 to the current collecting part 222 may be set to the same as the focal length of the condenser lens. In this case, damage to the current collecting part 222 by the laser 801 is prevented by adjusting the output of the laser irradiation device 800.

[0088] In the first embodiment, an example has been described in which the laser 801 is irradiated onto the laser irradiation area 232, gas is blown onto the laser irradiation area 232, and the blown gas is sucked in during the residue removal process. However, the gas blowing and suction may be omitted. Alternatively, only one of the gas blowing and suction may be omitted.

[0089] In the first embodiment, a metal bonded body formed by ultrasonically bonding a charge / discharge body 100 and a current collector 200 has been described. In the second embodiment, a metal bonded body (busbar 900) formed by ultrasonically bonding a positive electrode bonding plate 910 and a negative electrode bonding plate 920 has been described. However, the present invention is not limited thereto. The present invention can be applied to various products including a metal bonded body formed by ultrasonically bonding multiple metal members. One metal member has multiple press marks formed by ultrasonic bonding and laser marks formed superimposed on the multiple press marks. The press marks and laser marks are formed on the surface of the one metal member opposite the bonding surface with another metal member. With this configuration, defects caused by metal powder and burrs can be suppressed in products using the metal bonded body.

[0090] The battery is not limited to a lithium-ion battery. Examples of applicable batteries include nickel-metal hydride batteries and lead-acid batteries. The battery may be a secondary battery or a primary battery. The charge / discharge body of the battery of the present invention is not limited to a wound type 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 may be a stacked type in which multiple rectangular positive electrodes, separators, and negative electrodes are alternately stacked. The charge / discharge body of the battery of the present invention may 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 may be applicable 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 with 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.

[0091] 1...battery, 9...residue (metal powder, burrs), 100...charge / discharge body (electrode group), 110...positive electrode (electrode), 111...positive electrode current collector foil (metal member), 111a...side portion, 112...positive electrode active material layer (active material layer), 120...negative electrode (electrode), 121...negative electrode current collector foil (metal member), 121a...side portion, 121b...negative electrode side bundling portion, 121c...surface, 122...negative electrode active material layer (active material layer), 130...separator, 140...electrolyte, 200...current collector (metal member), 210...positive electrode current collector plate (metal member), 21 1...base, 211a...insertion hole, 212...current collecting portion, 220...negative electrode current collecting plate (metal member), 221...base, 221a...insertion hole, 222...current collecting portion, 229...metal joint, 231, 231B, 231C...pressure mark, 232, 232B, 232C...laser irradiated area (area), 233, 233B, 233C...laser mark, 233a...laser spot mark, 300...electrode terminal, 310...positive electrode terminal, 311...base, 312...insertion portion, 313...joint portion, 314...sealing portion, 320...negative Electrode terminal, 321...base, 322...insertion portion, 323...joint portion, 324...sealing portion, 400...exterior body, 410...container, 410a...opening, 410b...accommodation portion, 420...lid, 420a...positive electrode side insertion hole, 420b...negative electrode side insertion hole, 420c...insertion hole for liquid injection, 430...split valve, 440...sealing plug, 440a...head, 440b...insertion portion, 500...insulator, 510...insulating cover, 520...positive electrode side insulating plate, 521...base, 521a...through hole, 522...edge portion, 530...negative electrode side insulating plate, 31...base, 531a...through hole, 532...edge, 600...sealing body, 610...positive electrode side gasket, 611...base, 612...insertion portion, 613...edge, 620...negative electrode side gasket, 621...base, 622...insertion portion, 623...edge, 700, 700B...ultrasonic bonding device, 710, 710B...horn (ultrasonic horn), 711...horn body, 711a...opposing surface, 712, 712B...protrusion, 720, 720C...anvil, 721...anvil body, 721a...opposing surface, 722,722C...protrusion, 800...laser irradiation device, 801...laser (short pulse laser), 802...spot light, 900...bus bar (metal bonded body), 910...positive electrode bonding plate, 911...base end portion, 912...tip portion, 913...extension portion, 920...negative electrode bonding plate, 921...base end portion, 922...tip portion, 923...extension portion, 1000...battery assembly, DL...spot diameter, X...longitudinal direction of battery, Y...short direction of battery, Z...height direction of battery.

Claims

1. A metal bonded body formed by ultrasonically bonding a plurality of metal members, wherein one of the metal members has a plurality of pressure marks formed by ultrasonic bonding and laser marks formed superimposed on the plurality of pressure marks, and the pressure marks and the laser marks are formed on the surface of one of the metal members opposite to the bonding surface with the other of the metal members.

2. A metal bonded body according to claim 1, wherein the laser mark is composed of a plurality of laser spot marks, and the laser spot marks are smaller than the pressure marks.

3. A metal bonded body according to claim 1, wherein the laser mark is composed of a plurality of laser spot marks, and adjacent laser spot marks overlap each other.

4. A battery having a metal joined body formed by ultrasonically joining a plurality of metal members, the battery comprising: an electrode group in which electrodes and separators are stacked one on top of the other; a current collector plate joined to the electrode group; and an exterior body that houses the electrode group and the current collector plate, wherein the electrodes have a current collector foil and an active material layer, the current collector plate, which is one of the metal members, and the current collector foil, which is another of the metal members, are joined by ultrasonically joining, and the current collector plate has a plurality of pressure marks formed by ultrasonic joining and laser marks formed superimposed on the plurality of pressure marks, and the pressure marks and the laser marks are formed on the surface of the current collector plate opposite to the surface joined to the current collector foil.

5. A method for manufacturing a metal bonded body, comprising: an ultrasonic bonding step of bonding a plurality of metal members by clamping the metal members between an anvil and a horn and applying ultrasonic vibrations while pressing the metal members; and a residue removal step of removing residues generated in the ultrasonic bonding step from an area including a plurality of indentations formed on the metal members by pressing in the ultrasonic bonding step by irradiating the area with a laser.

6. A method for manufacturing a metal bonded body according to claim 5, wherein in the residue removal step, the laser spot light irradiated on the region is smaller than the indentation mark.

7. A method for producing a metal bonded body according to claim 6, wherein in the residue removal step, the laser is irradiated onto the metal members at a position where the distance from the focusing lens of a laser irradiation device to the metal members is shorter or longer than the focal length of the focusing lens.

8. A method for producing a metal bonded body according to claim 6, wherein in the residue removal step, the region is irradiated with a laser, and a gas is blown onto the region, and the blown gas is sucked.

Images