WO2019177081A1 - Manufacturing method for sealed battery, and sealed battery - Google Patents

Manufacturing method for sealed battery, and sealed battery Download PDF

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Publication number
WO2019177081A1
WO2019177081A1 PCT/JP2019/010460 JP2019010460W WO2019177081A1 WO 2019177081 A1 WO2019177081 A1 WO 2019177081A1 JP 2019010460 W JP2019010460 W JP 2019010460W WO 2019177081 A1 WO2019177081 A1 WO 2019177081A1
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WIPO (PCT)
Prior art keywords
negative electrode
melting
lead
sealed battery
electrode lead
Prior art date
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PCT/JP2019/010460
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French (fr)
Japanese (ja)
Inventor
信也 森
翔太 池田
一路 清水
船見　浩司
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三洋電機株式会社
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Publication of WO2019177081A1 publication Critical patent/WO2019177081A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H01M50/536—Electrode connections inside a battery casing characterised by the method of fixing the leads to the electrodes, e.g. by welding
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings; Jackets or wrappings
    • H01M50/102—Primary casings; Jackets or wrappings characterised by their shape or physical structure
    • H01M50/107—Primary casings; Jackets or wrappings characterised by their shape or physical structure having curved cross-section, e.g. round or elliptic
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/528—Fixed electrical connections, i.e. not intended for disconnection
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present disclosure relates to a method for manufacturing a sealed battery and a sealed battery.
  • secondary batteries are expected not only to be used by being incorporated in electronic devices such as personal computers, but also as a power source for supplying power to a vehicle driving motor.
  • a non-aqueous electrolyte secondary battery when an internal short circuit occurs due to mixing of a metal foreign substance into the battery instead of obtaining high energy, there is a possibility that problems such as heat generation of the battery itself may occur.
  • the outer can and the lead connected to one of the positive electrode and the negative electrode of the electrode body are mainly connected by resistance welding.
  • this resistance welding has a problem that spatter is generated inside the battery during the welding process, and metal foreign matter is mixed in the battery, thereby deteriorating the manufacturing quality, safety, and reliability of the battery due to voltage failure. Therefore, in recent years, an energy beam such as a laser beam is irradiated from the outside of the outer can to weld the outer can and the lead to prevent spattering (see, for example, Patent Documents 1 to 3). .
  • Patent Document 4 describes a battery manufacturing method in which an energy beam is irradiated in two stages from the outside of the outer can and the outer can and the cap body are welded.
  • laser light irradiated with the first laser output and the second laser output is used as the pulsed laser light.
  • the first laser output heats the laser irradiation side member of the overlapping member to eliminate organic substances between the overlapping members.
  • the second laser output melts the laser irradiation side member of the overlapping member and welds the plurality of overlapping members.
  • JP 2010-3686 A Japanese Patent Laying-Open No. 2015-162326 Japanese Unexamined Patent Publication No. 2016-207212 Japanese Patent Laid-Open No. 11-245066
  • the solid resin When resin is present between the outer can and lead, if the energy beam is irradiated to the outer can, the solid resin may sublimate or the liquid resin may be vaporized by the heat generated by the irradiation. There is. Due to the sublimation or vaporization of the resin, the volume of the gas may expand at a stretch between the outer can and the lead, and the gas may escape toward the outside of the outer can that is melted by the energy beam. As a result, there is a possibility that the outer can has a hole formed from the inner side to the outer side, and the sealing inside the battery cannot be maintained.
  • a concave hole may be formed on the welded surface with the lead on the inner surface of the outer can, and this hole reduces the weld area between the outer can and the lead. By decreasing, the welding strength may be reduced.
  • Patent Document 4 discloses only eliminating the inconvenience when the electrolyte enters between the overlapping members after the electrolyte is injected into the outer can.
  • the present disclosure aims to prevent generation of a hole penetrating the outer can when the lead is welded to the outer can and to obtain a stable welding strength in the sealed battery manufacturing method and the sealed battery.
  • a method for manufacturing a sealed battery according to the present disclosure includes an electrode body in which at least one positive electrode and at least one negative electrode are wound or stacked with a separator interposed therebetween, and a bottomed cylindrical outer can that houses the electrode body.
  • a sealed battery manufacturing method comprising: a welding step of irradiating an energy beam from the outside of an outer can and welding a lead connected to one of a positive electrode and a negative electrode to the outer can. First irradiation for irradiating a first energy beam that is controlled so that a first melted portion, which is a melting mark, remains inside the outer can at a portion of the outer surface facing the lead through the inner surface of the outer can.
  • a second molten portion that is a melting mark is formed from the outer surface of the outer can to the inside of the lead inside the portion of the outer surface of the outer can where the first molten portion is exposed.
  • Controlled to It has a second irradiation step of irradiating the second energy beam, and a method of manufacturing a sealed battery.
  • a sealed battery according to the present disclosure includes an electrode body in which at least one positive electrode and at least one negative electrode are wound or laminated with a separator interposed therebetween, and a bottomed cylindrical outer can that houses the electrode body.
  • the outer can is made of nickel-plated iron, and the lead connected to one of the positive electrode and the negative electrode and the outer can are welded at a weld formed from the outer surface of the outer can toward the lead.
  • the welded portion includes a first melted portion and a second melted portion that are melt marks, and the first melted portion is formed in the range of 50 to 99% of the thickness of the outer can from the outer surface of the outer can.
  • the second melting portion is formed from the outer surface of the outer can to the inside of the lead, and is a sealed battery that is inside the first melting portion when the welded portion is viewed from the outer side of the outer can.
  • the method for manufacturing a sealed battery and the sealed battery according to the present disclosure it is possible to prevent generation of a hole penetrating the outer can when the lead is welded to the outer can, and to obtain a stable welding strength.
  • FIG. 10 is a bottom view of the sealed battery shown in FIG. 9.
  • the sealed battery is a cylindrical non-aqueous electrolyte secondary battery
  • the sealed battery is not limited to a cylindrical battery, and may be a prismatic battery or the like.
  • the sealed battery is not limited to a non-aqueous electrolyte secondary battery as described below, and is a secondary battery such as a nickel metal hydride battery or a nickel cadmium battery, or a primary battery such as a dry battery or a lithium battery. May be.
  • the electrode body included in the battery is not limited to the winding type as described below, and may be a stacked type in which a plurality of positive electrodes and negative electrodes are alternately stacked via separators.
  • FIG. 1 is a cross-sectional view of the bottom half of a sealed battery 20 manufactured by an exemplary manufacturing method of an embodiment.
  • FIG. 2 is a bottom view of the sealed battery 20.
  • FIG. 3 is an enlarged view of a portion A in FIG.
  • FIG. 4 is an enlarged view of a portion B in FIG. 5 is a cross-sectional view taken along the line CC of FIG.
  • the sealed battery 20 is referred to as a battery 20.
  • the battery 20 includes a wound electrode body 22, a non-aqueous electrolyte (not shown), and an outer can 50.
  • the wound electrode body 22 includes a positive electrode 23, a negative electrode 24, and a separator 25, and the positive electrode 23 and the negative electrode 24 are stacked via the separator 25 and wound in a spiral shape.
  • the one axial side of the electrode body 22 may be referred to as “upper” and the other axial side may be referred to as “lower”.
  • the non-aqueous electrolyte includes a non-aqueous solvent and an electrolyte salt such as a lithium salt dissolved in the non-aqueous solvent.
  • the nonaqueous electrolyte is not limited to a liquid electrolyte, and may be a solid electrolyte using a gel polymer or the like.
  • the positive electrode 23 has a strip-shaped positive electrode current collector 23a, and a positive electrode lead (not shown) is connected to the positive electrode current collector 23a.
  • the positive electrode lead is a conductive member for electrically connecting the positive electrode current collector 23a to a positive electrode terminal (not shown), and is one side (in FIG. 1) of the electrode body 22 in the axial direction ⁇ from the upper end of the electrode group. (Upward).
  • the electrode group means a portion of the electrode body 22 excluding each lead.
  • the positive electrode lead is provided, for example, at a substantially central portion of the electrode body 22 in the radial direction ⁇ .
  • the negative electrode 24 has a strip-shaped negative electrode current collector 24a, and a negative electrode lead 26 is connected to the negative electrode current collector 24a.
  • the negative electrode lead 26 is a conductive member for electrically connecting the negative electrode current collector 24a to the outer can 50 serving as a negative electrode terminal, and the other end in the axial direction ⁇ from the lower end of the winding end side end portion of the electrode group ( It extends in the lower part of FIG.
  • the constituent material of each lead is not particularly limited.
  • the positive electrode lead can be composed of a metal mainly composed of aluminum
  • the negative electrode lead 26 can be composed of a metal mainly composed of nickel or copper or a metal including both nickel and copper.
  • the negative electrode lead 26 may be formed from nickel-plated iron.
  • the negative electrode lead 26 is bent at a substantially right angle so as to face the winding core portion of the electrode body 22 through the insulating plate 30 and is in contact with the inner surface of the bottom plate portion 51.
  • the outer can 50 and the negative electrode lead 26 are welded by the welded portion 54 by sequentially irradiating the first laser beam 40 and the second laser beam 41 toward the bottom plate portion 51 from the outside of the outer can 50.
  • the welded portion 54 refers to a portion formed by melt marks that are melted and solidified by irradiation with the laser beams 40 and 41.
  • the weld 54 is formed from the outer surface of the outer can 50 toward the negative electrode lead 26.
  • the first laser beam 40 corresponds to a first energy beam
  • the second laser beam 41 corresponds to a second energy beam. The weld 54 and the welding process will be described in detail later.
  • the outer can 50 is a container formed by processing a nickel-plated iron material into a bottomed cylindrical shape.
  • the iron used for the outer can 50 can contain dissimilar metals or the like as long as the battery characteristics are not adversely affected.
  • the opening of the outer can 50 is sealed with a sealing body (not shown).
  • the outer can 50 accommodates the electrode body 22 and the nonaqueous electrolyte.
  • An insulating plate 30 is disposed below the electrode body 22.
  • the negative electrode lead 26 passes through the outside of the insulating plate 30, extends to the bottom side of the outer can 50, and is welded to the inner surface of the bottom plate portion 51 of the outer can 50.
  • the thickness of the bottom plate portion 51 that is the bottom portion of the outer can 50 is, for example, 0.2 to 0.5 mm.
  • the electrode body 22 has a winding structure in which a positive electrode 23 and a negative electrode 24 are wound in a spiral shape with a separator 25 interposed therebetween.
  • the positive electrode 23, the negative electrode 24, and the separator 25 are all formed in a band shape, and are wound in a spiral shape to be alternately stacked in the radial direction ⁇ of the electrode body 22.
  • the winding core portion 29 including the winding center axis O of the electrode body 22 is a cylindrical space.
  • the positive electrode 23 has a positive electrode active material layer formed on the positive electrode current collector 23a.
  • the positive electrode active material layer is formed on both surfaces of the positive electrode current collector 23a.
  • a metal foil such as aluminum, a film in which the metal is disposed on the surface layer, or the like is used.
  • a suitable positive electrode current collector 23a is a metal foil that is stable in the potential range of the positive electrode such as a metal mainly composed of aluminum or an aluminum alloy.
  • the positive electrode active material layer preferably contains a positive electrode active material, a conductive agent, and a binder.
  • the positive electrode 23 is formed by, for example, applying a positive electrode mixture slurry containing a positive electrode active material, a conductive agent, a binder, and a solvent such as N-methyl-2-pyrrolidone (NMP) on both surfaces of the positive electrode current collector 23a, and then drying. And it is produced by rolling.
  • NMP N-methyl-2-pyrrolidone
  • the positive electrode active material examples include lithium-containing transition metal oxides containing transition metal elements such as Co, Mn, and Ni.
  • the lithium-containing transition metal oxide is not particularly limited, but has the general formula Li 1 + x MO 2 (wherein ⁇ 0.2 ⁇ x ⁇ 0.2, M includes at least one of Ni, Co, Mn, and Al) It is preferable that it is complex oxide represented by these.
  • Examples of the conductive agent include carbon materials such as carbon black (CB), acetylene black (AB), ketjen black, and graphite.
  • Examples of the binder include fluorine resins such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), polyimide (PI), acrylic resin, and polyolefin resin. It is done. These resins may be used in combination with carboxymethylcellulose (CMC) or a salt thereof, polyethylene oxide (PEO), and the like. These may be used alone or in combination of two or more.
  • the negative electrode 24 has a negative electrode active material layer formed on the negative electrode current collector 24a.
  • the negative electrode active material layer is formed on both surfaces of the negative electrode current collector 24a.
  • a metal foil that is stable in the potential range of a negative electrode such as aluminum or copper, or a film in which the metal is disposed on the surface layer is used.
  • the negative electrode active material layer is formed on both sides of the negative electrode current collector 24a over the entire area excluding a solid portion described later.
  • the negative electrode active material layer preferably contains a negative electrode active material and a binder.
  • the negative electrode active material layer may contain a conductive agent as necessary.
  • the negative electrode 24 is produced, for example, by applying a negative electrode mixture slurry containing a negative electrode active material, a binder, water, and the like to both surfaces of the negative electrode current collector 24a, followed by drying and rolling.
  • the negative electrode active material is not particularly limited as long as it can reversibly occlude and release lithium ions.
  • carbon materials such as natural graphite and artificial graphite, metals such as Si and Sn, alloys with lithium, or these An alloy, a composite oxide, or the like containing can be used.
  • the binder contained in the negative electrode active material layer for example, the same resin as that of the positive electrode 23 is used.
  • SBR styrene-butadiene rubber
  • CMC styrene-butadiene rubber
  • polyacrylic acid or a salt thereof, polyvinyl alcohol, or the like can be used. These may be used alone or in combination of two or more.
  • the negative electrode 24 is provided with a plain portion where the surface of the negative electrode current collector 24a is exposed.
  • the plain portion is a portion to which the negative electrode lead 26 is connected, and the surface of the negative electrode current collector 24a is not covered with the negative electrode active material layer.
  • the plain portion has a substantially rectangular shape in front view extending long along the axial direction ⁇ which is the width direction of the negative electrode 24, and is formed wider than the negative electrode lead 26.
  • the negative electrode lead 26 is joined to the surface of the negative electrode current collector 24a by, for example, ultrasonic welding. It should be noted that a negative electrode lead different from the negative electrode lead 26 is provided not only at the winding end side end portion of the negative electrode 24 but also at the winding direction intermediate portion and the winding start side end portion, and extends from the electrode group to the bottom plate portion 51 side.
  • the extended negative electrode lead can be overlapped on the negative electrode lead 26 at the winding core and welded to the outer can 50 by laser light irradiation.
  • the plain portion is provided, for example, by intermittent application without applying the negative electrode mixture slurry to a part of the negative electrode current collector 24a.
  • the positive electrode lead is bonded to a plain portion formed on the positive electrode current collector 23a, and a portion protruding upward from the positive electrode current collector 23a is bonded to a positive electrode terminal or a portion connected to the positive electrode terminal.
  • a porous sheet having ion permeability and insulating properties is used as the separator 25 .
  • the porous sheet include a microporous thin film, a woven fabric, and a non-woven fabric.
  • an olefin resin such as polyethylene and polypropylene is preferable.
  • the weld 54 is formed by melting marks as described above. As shown in FIG. 4, when the welded portion 54 is viewed from the outside (the lower side of FIG. 1) of the bottom plate portion 51 of the outer can 50, the second melting portion 58 is first melted so as to surround the entire circumference. It is inside the portion 56 and exposed on the outer surface of the outer can 50. In this state, the second melting part 58 welds the outer can 50 and the negative electrode lead 26 (FIG. 3). The second melting part 58 is formed deeper than the first melting part 56.
  • the first melting part 56 is formed so as to remain inside the outer can 50.
  • the first melting portion 56 is formed by irradiating the first laser light 40 from the outside of the outer can 50 toward the bottom plate portion 51 in a first irradiation step described later.
  • the second melting part 58 is formed by irradiating the second laser light 41 from the outside of the outer can 50 toward the bottom plate part 51 in the second irradiation process after the first irradiation process, as will be described later.
  • the first melting part 56 has a linear planar shape when viewed from the outside of the bottom plate part 51 of the outer can 50.
  • the second melting part 58 also has a linear shape when viewed from the outside of the bottom plate part 51, and the width w ⁇ b> 2 of the second melting part 58 is smaller than the width w ⁇ b> 1 of the first melting part 56.
  • the second melting part 58 has a higher nickel content (mass%) than the first melting part 56.
  • melting part 58 can be confirmed by observing from the outer side of the armored can 50, for example.
  • the presence of the first melting part 56 and the second melting part 58 can be confirmed by observing, for example, an optical microscope or the like in the thickness direction of the outer can 50 of the melt mark.
  • the spot diameter of the fiber laser can be made very small, for example, about 0.02 mm to 0.05 mm, so that the width of the melt mark formed by the fiber laser can be made very small, about 0.1 mm. For this reason, the power density of the condensing point of a laser beam can be made very high.
  • the second laser light 41 is irradiated so that melt marks formed by the irradiation of the second laser light 41 penetrate the outer can 50 but not the negative electrode lead 26.
  • the spot diameter of the first laser beam 40 when forming the first melting part 56 is larger than the spot diameter of the second laser beam 41.
  • the first laser beam 40 is irradiated so that melt marks formed by the irradiation of the first laser beam 40 do not penetrate the outer can 50 and do not reach the negative electrode lead 26.
  • the irradiation portion of the first laser light 40 is moved on the outer surface of the bottom plate portion 51 of the outer can 50 along one direction (for example, the right side in FIG. 1) along the linear direction, and the first melting is performed.
  • a portion 56 is formed.
  • the second melting part 58 formed by the second laser light 41 is formed inside the first melting part 56 formed by irradiation with the first laser light 40.
  • the battery 20 can be arranged with the bottom plate portion 51 facing upward, and laser light can be irradiated toward the bottom portion. It is also possible to arrange the battery 20 in a state where it is tilted sideways and irradiate the bottom plate portion 51 with laser light.
  • the welding process includes a first irradiation process and a second irradiation process.
  • the first irradiation step and the second irradiation step are performed before injecting the electrolyte into the outer can 50.
  • FIG. 6 is a diagram in which the first laser beam 40 is irradiated in the first irradiation step in the manufacturing method of the embodiment.
  • FIG. 7 is a diagram for irradiating the second laser light 41 in the second irradiation step in the manufacturing method of the embodiment.
  • the electrode body 22 Before performing the first irradiation step, the electrode body 22 is accommodated in the outer can 50 with the negative electrode lead 26 facing the inner surface of the bottom plate portion 51 of the outer can 50.
  • laser light is irradiated in two stages from the outside of the outer can 50 toward the bottom plate portion 51 by the first irradiation process and the second irradiation process.
  • a presser bar 70 is inserted into the outer can 50 from above, and is pressed by the presser bar 70.
  • the negative electrode lead 26 is pressed from above through the insulating plate 30.
  • the outer can 50 and the negative electrode lead 26 are brought into close contact with each other, and in this state, a portion of the outer surface of the bottom plate portion 51 facing the negative electrode lead 26 through the inner surface of the bottom plate portion 51 is first.
  • Irradiation with a first laser beam 40 having an energy amount forms the first melted portion 56.
  • the first melting portion 56 that is a melting mark does not penetrate the outer can 50 at the irradiation position of the first laser light 40, stays inside the outer can 50, and does not reach the negative electrode lead 26.
  • the laser beam 40 is controlled. At this time, it is preferable that the spot diameter of the first laser light 40 is larger than the spot diameter of the second laser light 41 described later.
  • the irradiation part of the 1st laser beam 40 is moved in the outer surface of the bottom plate part 51 of the armored can 50 toward one side (for example, the right side of FIG. 6) along the linear direction.
  • the light source of the laser light is moved so that the battery 20 is relatively moved in a direction orthogonal to the irradiation direction of the laser light.
  • the negative electrode lead 26 is pressed by the presser bar 70 through the insulating plate 30.
  • a hole is provided in the central portion of the insulating plate 30 and the presser bar penetrating the hole directly presses the negative electrode lead 26. May be.
  • the outer canister is pressed by the presser bar 70 in the same manner as in the first irradiation step. 50 and the negative electrode lead 26 are brought into close contact with each other.
  • the second laser beam 41 having the second energy amount is irradiated from the outside toward the bottom plate portion 51 to the inside of the portion where the first melting portion 56 is exposed, and the second melting portion 58 is irradiated.
  • the second laser beam 42 is controlled so that a second melted portion that is a melt mark is formed from the outer surface of the bottom plate portion 51 to the inside of the negative electrode lead 26.
  • the irradiation part of the second laser light 41 is moved on the outer surface of the bottom plate part 51 of the outer can 50 along one of the linear directions (for example, the right side in FIG. 7). 2 to form the melted portion 58.
  • the second melting part 58 is formed so as to melt a part of the outer can 50 and the negative electrode lead 26 in the range inside the melt mark formed by the irradiation of the first laser beam 40.
  • a part of the first melting part 56 is melted and solidified to be changed into the second melting part 58, and the second melting part 58 remains without changing to the second melting part 58 in the first melting part 56. It is formed adjacent to the part.
  • the laser light source is moved so that the battery 20 is relatively moved in the direction orthogonal to the laser light irradiation direction.
  • the outer can 50 and the negative electrode lead 26 are welded by irradiating the first laser beam 40 from the outside of the outer can 50 in a state where the outer can 50 and the negative electrode lead 26 are in close contact with each other by the holding rod 70. It is easy to prevent spatter from occurring inside the battery 20.
  • the second melting part 58 is formed inside the first melting part 56 on the outer surface of the bottom plate part 51, and extends in the inner side (upper side in FIG. 1) direction of the bottom plate part 51 and the second melting part 58. Is located inside the bottom plate portion 51.
  • the first laser beam 40 and the second laser beam 41 are irradiated so that the irradiation unit moves on the outer surface of the bottom plate unit 51 along the same linear direction.
  • the planar shape when viewed from the outside of the bottom plate part 51 of the first melting part 56 and the second melting part 58 is formed in a straight line.
  • the entire second melting portion 58 is surrounded by the first melting portion 56.
  • the irradiation part of a laser beam should just move relatively with respect to the outer surface of the armored can 50, and the armored can 50 may be actually moved among laser light and the armored can 50.
  • the holes penetrating the outer can 50 when welding the negative electrode lead 26 to the outer can 50 in a state before the electrolyte is injected into the outer can 50.
  • production can be prevented and stable welding strength can be obtained.
  • resin is present between the outer can 50 and the negative electrode lead 26 by irradiating the first laser beam 40 forming the first melting portion 56 to the bottom plate portion 51, the resin is sublimated or the like. Vaporize.
  • the second laser beam 41 that forms the second melting portion 58 is irradiated to the inside of the first melting portion 56 in a state where no resin exists between the outer can 50 and the negative electrode lead 26, and the outer can 50 and the negative electrode
  • the lead 26 can be welded. For this reason, generation
  • production can be suppressed and stable welding strength can be obtained. be able to.
  • the welded portion 54 includes the first melted portion 56 and the second melted portion 58 shown in FIGS. 1 and 2, stress corrosion cracking in the bottom plate portion 51 caused by the welded portion 54 occurs. It becomes difficult.
  • FIG. 8 is a diagram of irradiating the first laser beam 40 in another manufacturing method according to the embodiment.
  • the manufacturing method of this example when the first laser beam 40 that forms the first melting portion 56 is irradiated to the outer surface of the bottom plate portion 51 in the first irradiation step, there is a gap between the outer can 50 and the negative electrode lead 26. S1 is opened.
  • the pressing rod is not inserted into the outer can 50 from the upper side, and the negative electrode lead 26 is pressed from the upper side. Do not do.
  • the gap S1 formed between the outer can 50 and the negative electrode lead 26 may be about 0.005 mm to 0.2 mm. Due to the presence of the gap S1, the heat generated by the irradiation of the first laser beam 40 stays in the outer can 50, and the negative electrode lead 26 or the pressing rod that closely contacts the outer can 50 and the negative electrode lead 26. Heat is not absorbed. For this reason, the resin existing between the outer can 50 and the negative electrode lead 26 is efficiently vaporized. After that, as in the manufacturing method shown in FIG. 7, when the second laser beam 41 that forms the second melting portion 58 is irradiated to the bottom plate portion 51, the outer can 50 and the negative electrode lead 26 are brought into close contact with the pressing rod 70. In this state, the outer can 50 and the negative electrode lead 26 are welded.
  • the laser spot diameter of the first laser beam 40 that forms the first melting part 56 is preferably larger than the laser spot diameter of the second laser beam 41 that forms the second melting part 58. Since the first laser beam 40 is irradiated so that the resin existing between the outer can 50 and the negative electrode lead 26 is vaporized by heat, the resin is vaporized and removed in a region wider than the region where the second melting portion 58 is formed. It is preferable to do. In other words, the second laser light 41 is irradiated to the area where the resin existing between the outer can 50 and the negative electrode lead 26 is removed by the first laser light 40, thereby forming the second melting portion 58, The outer can 50 and the negative electrode lead 26 are welded. Thereby, generation
  • the irradiation depth of the first laser beam 40 and the second laser beam 41 and the irradiation area of the first laser beam 40 can be controlled with high accuracy. Accordingly, the dimensions (thickness, width, length) of the first melting part 56 and the second melting part 58 can be controlled with high accuracy, and the resin existing between the outer can 50 and the negative electrode lead 26 can be efficiently vaporized. Can be removed.
  • melting part 58 at the time of seeing the welding part 54 from the outer side of the armored can 50 should just be linear, and is not limited to linear form. For example, the planar shapes of the first melting part 56 and the second melting part 58 may be curved.
  • Example 1 Although the dimension of the structure of Example 1 is illustrated, this indication is not limited to the following dimensions.
  • the width w ⁇ b> 1 in the short direction when the first melting portion 56 is viewed from the outside of the outer can 50 is the width in the short direction when the second melting portion 58 is viewed from the outside of the outer can 50. It is larger than w2 and not more than 3 times the width w2.
  • the length L1 in the longitudinal direction when the first melting portion 56 is viewed from the outside of the outer can 50 is the length L2 in the longitudinal direction when the second melting portion 58 is viewed from the outside of the outer can 50. It is larger and not more than twice the length L2.
  • the thickness D1 of the first melting portion 56 is 0.5 to 0.99 times the thickness Dc of the outer can 50.
  • the outer can 50 is made of nickel-plated iron, and the nickel plating layer on the outer surface has a thickness of 3.5 ⁇ m.
  • the total thickness of the outer can 50 including the nickel plating layer is 300 ⁇ m.
  • melting part 58 is as follows.
  • Example 1 In the manufacturing method of Example 1, a general facility lubricating oil was applied between the outer can 50 and the negative electrode lead 26 in order to confirm the effect of the embodiment. Thereafter, in the first irradiation step, the first laser beam 40 that forms the first melting portion 56 is emitted from the outside of the outer can 50 in a state where the outer can 50 and the negative electrode lead 26 are brought into close contact with the pressing rod 70 (FIG. 6). The bottom plate part 51 was irradiated. After that, in the second irradiation step, by irradiating the second laser beam 41 that forms the second melting portion 58 in a state where the outer can 50 and the negative electrode lead 26 are brought into close contact with the pressing rod 70 (FIG. 7), The outer can 50 and the negative electrode lead 26 were welded.
  • the irradiation conditions of the first laser beam 40 and the second laser beam 41 are as follows. (First laser beam 40) (1) Energy: 1.44J (2) Laser spot diameter: 170 ⁇ m (3) Movement speed: 470 mm / sec (Second laser beam 41) (1) Energy: 0.6J (2) Laser spot diameter: 20 ⁇ m (3) Movement speed: 470 mm / sec
  • melt marks were formed inside the outer can 50 by irradiation with the first laser light 40.
  • the melt mark has a width in the short direction of 170 ⁇ m on the outer surface of the outer can 50, a length in the long direction of 1600 ⁇ m, and a thickness (the length from which the first melting portion 56 is formed from the outer surface of the outer can 50. ) was 270 ⁇ m.
  • the width of the short direction is 80 ⁇ m
  • the length in the long direction is 1000 ⁇ m
  • the thickness (exterior) The length of the second melted portion 58 formed from the outer surface of the can 50 was 350 ⁇ m.
  • Example 2 corresponds to another manufacturing method of the embodiment shown in FIG.
  • the configuration and dimensions of the battery of Example 2 are the same as those of Example 1.
  • general equipment lubricating oil was applied between the outer can 50 and the negative electrode lead 26.
  • a gap is provided between the outer can and the negative electrode lead without causing the presser bar to closely contact the outer can and the negative electrode lead.
  • the first laser beam 40 that forms the first melting part 56 was applied to the bottom plate part 51 from the outside of the outer can 50.
  • the outer can 50 and the negative electrode lead 26 were welded by irradiating 41.
  • the irradiation conditions of the first laser beam 40 and the second laser beam 41 are the same as those in the first embodiment.
  • the second melting portion 58 is formed by irradiating the second laser beam 41 without irradiating the first laser beam 40 forming the first melting portion 56 (FIGS. 6 and 8).
  • a battery in which the outer can and the negative electrode lead were welded was produced.
  • the first melting part was not formed at the bottom of the outer can, and only the second melting part 58 for welding the negative electrode lead and the outer can was formed.
  • the other configurations and dimensions of the battery and the irradiation conditions of the second laser light are the same as those in the first embodiment.
  • Table 1 shows the results of confirming the probability of occurrence of a hole penetrating the outer can 50 using the batteries of Examples 1 and 2 and Comparative Example produced by each of the above manufacturing methods. In the experiment, a plurality of batteries were produced in each of Examples 1 and 2 and Comparative Example, and the probability of occurrence of holes was confirmed.
  • the outer can 50 is formed. It has been confirmed that the probability of occurrence of a hole penetrating through is reduced to 5%.
  • the outer can 50 when a gap is provided between the outer can 50 and the negative electrode lead 26 and the first laser beam 40 that forms the first melting portion 56 is irradiated without being in close contact with each other, the outer can It was confirmed that the probability of occurrence of holes penetrating 50 decreased to 0%.
  • the probability of occurrence of holes penetrating the outer can 50 could be reduced.
  • Example 2 the reason for this is that in Example 2, the heat generated by the irradiation of the first laser beam 40 stays in the outer can 50, and the negative electrode lead 26, or the presser bar that closely contacts the outer can 50 and the negative electrode lead 26. This is because heat is not absorbed by the heat sink. For this reason, in Example 2, the resin existing between the outer can 50 and the negative electrode lead 26 could be efficiently vaporized.
  • FIG. 9 is a cross-sectional view of the bottom half of a battery 20a according to another example of the embodiment. 10 is a bottom view of the battery 20a shown in FIG.
  • a weld group 60 including three linear parallel welds 54 a, 54 b and 54 c for welding the outer can 50 and the negative electrode lead 26 is formed.
  • the welded group 60 including the three welded portions 54a, 54b, and 54c it is easy to ensure the welding strength between the outer can 50 and the negative electrode lead 26.
  • 9 and 10 show a weld group 60 composed of three parallel welds.
  • the number of welds is not limited to three, but two or more than four.
  • a weld of a book may be formed. When forming such a weld locally, it is preferable to use a laser beam of a fiber laser. In this example, other configurations and operations are the same as those in FIGS. 1 to 7.
  • 20 20a sealed battery (battery), 22 electrode body, 23 positive electrode, 23a positive electrode current collector, 24 negative electrode, 24a negative electrode current collector, 25 separator, 26 negative electrode lead, 29 winding core, 30 insulating plate, 40 1st Laser beam, 41, second laser beam, 50 outer can, 51 bottom plate, 54, 54a, 54b, 54c weld, 56 first melt, 58 second melt, 60 weld group, 70 presser bar.

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  • Chemical Kinetics & Catalysis (AREA)
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  • Connection Of Batteries Or Terminals (AREA)
  • Sealing Battery Cases Or Jackets (AREA)

Abstract

This manufacturing method for a sealed battery of a mode of the present disclosure includes a welding step for irradiating energy beams from outside an outer can, and welding a negative electrode lead (26) to an outer can (50). The welding step has: a first irradiation step for irradiating a first energy beam that is controlled so that a first melting part (56), which is a melting mark inside the outer can, stays in the portion of the outside surface of the outer can for which the negative electrode lead (26) opposes the interior side of the outer can across the inside surface; and a second irradiation step, subsequent to the first irradiation step, for irradiating a second energy beam that is controlled to have a second melting part (58), which is a melting mark, formed from the outside surface of the outer can to the interior of the negative electrode lead (26), on the inside of the portion of the outside surface of the outer can at which the first melting part is exposed.

Description

密閉電池の製造方法及び密閉電池Sealed battery manufacturing method and sealed battery
　本開示は、密閉電池の製造方法及び密閉電池に関する。 The present disclosure relates to a method for manufacturing a sealed battery and a sealed battery.
　近年の二次電池は、パソコン等の電子機器に組み込んで用いるだけでなく、車両の走行用のモータに電力を供給する電力源として期待されている。非水電解質二次電池は、高いエネルギーを得られる代わりに、電池内への金属異物などの混入による内部短絡が発生すると、電池自体の発熱等の問題が発生する可能性がある。 Recently, secondary batteries are expected not only to be used by being incorporated in electronic devices such as personal computers, but also as a power source for supplying power to a vehicle driving motor. In the non-aqueous electrolyte secondary battery, when an internal short circuit occurs due to mixing of a metal foreign substance into the battery instead of obtaining high energy, there is a possibility that problems such as heat generation of the battery itself may occur.
　従来、外装缶と、電極体の正極及び負極の一方に接続されたリードとは、主に抵抗溶接によって接続されている。しかしながらこの抵抗溶接は、溶接過程で電池内部でスパッタが発生し、金属異物が電池内に混入することで、電圧不良による電池の製造品質、安全性、及び信頼性が悪化する課題があった。そのため近年では、外装缶の外側からエネルギービーム、例えばレーザ光を照射して、外装缶とリードとを溶接させて、スパッタの発生を防止しているものがある（例えば特許文献１～３参照）。 Conventionally, the outer can and the lead connected to one of the positive electrode and the negative electrode of the electrode body are mainly connected by resistance welding. However, this resistance welding has a problem that spatter is generated inside the battery during the welding process, and metal foreign matter is mixed in the battery, thereby deteriorating the manufacturing quality, safety, and reliability of the battery due to voltage failure. Therefore, in recent years, an energy beam such as a laser beam is irradiated from the outside of the outer can to weld the outer can and the lead to prevent spattering (see, for example, Patent Documents 1 to 3). .
　また、特許文献４には、外装缶の外部から二段階に分けてエネルギービームを照射して、外装缶とキャップ体との溶接を行う電池の製造方法が記載されている。この電池の製造方法では、パルスレーザ光として、第１のレーザ出力及び第２のレーザ出力で照射されるレーザ光を用いる。第１のレーザ出力は、重ね合わせ部材のレーザ照射側部材を加熱し重ね合わせ部材の間の有機物を排除する。第２のレーザ出力は、重ね合わせ部材のレーザ照射側部材を溶融させて複数の重ね合わせ部材を溶接する。 Patent Document 4 describes a battery manufacturing method in which an energy beam is irradiated in two stages from the outside of the outer can and the outer can and the cap body are welded. In this battery manufacturing method, laser light irradiated with the first laser output and the second laser output is used as the pulsed laser light. The first laser output heats the laser irradiation side member of the overlapping member to eliminate organic substances between the overlapping members. The second laser output melts the laser irradiation side member of the overlapping member and welds the plurality of overlapping members.
特開２０１０－３６８６号公報JP 2010-3686 A 特開２０１５－１６２３２６号公報Japanese Patent Laying-Open No. 2015-162326 特開２０１６－２０７４１２号公報Japanese Unexamined Patent Publication No. 2016-207212 特開平１１－２４５０６６号公報Japanese Patent Laid-Open No. 11-245066
　外装缶の外部からエネルギービームを照射して、外装缶にリードを溶接する従来の電池の製造方法では、外装缶にエネルギービームを照射したときに、外装缶に内側から穴が形成される可能性がある。具体的には、外装缶にリードを溶接する直前の状態で、外装缶とリードの間に固体状または液状の樹脂が存在する場合がある。この樹脂は、潤滑油系樹脂、工程内での発塵樹脂、電池構成部材に付着した樹脂などに由来する。外装缶とリードの間に樹脂が存在する場合に、エネルギービームが外装缶に照射されると、その照射により発生した熱で、固体状の樹脂が昇華し、または液状の樹脂が気化する可能性がある。この樹脂の昇華、または気化によって、外装缶とリードとの間で気体の体積が一気に膨張し、エネルギービームにより溶融している外装缶の外側に向けて気体が抜ける可能性がある。これにより、外装缶に内側から外側に通じる穴が形成された状態となり、電池内部の密閉性が保てなくなる可能性がある。外装缶の外側まで穴が通じていない状態でも、外装缶の内面のうち、リードとの溶接面に凹部状の穴が形成される可能性もあり、この穴により外装缶とリードの溶接面積が減少することで、溶接強度が低下する可能性がある。 In the conventional battery manufacturing method in which the energy beam is irradiated from the outside of the outer can and the lead is welded to the outer can, there is a possibility that when the outer can is irradiated with the energy beam, a hole is formed in the outer can from the inside There is. Specifically, there may be a solid or liquid resin between the outer can and the lead just before welding the lead to the outer can. This resin is derived from a lubricating oil-based resin, a dust generating resin in the process, a resin adhering to the battery constituent member, and the like. When resin is present between the outer can and lead, if the energy beam is irradiated to the outer can, the solid resin may sublimate or the liquid resin may be vaporized by the heat generated by the irradiation. There is. Due to the sublimation or vaporization of the resin, the volume of the gas may expand at a stretch between the outer can and the lead, and the gas may escape toward the outside of the outer can that is melted by the energy beam. As a result, there is a possibility that the outer can has a hole formed from the inner side to the outer side, and the sealing inside the battery cannot be maintained. Even in a state where the hole does not reach to the outside of the outer can, a concave hole may be formed on the welded surface with the lead on the inner surface of the outer can, and this hole reduces the weld area between the outer can and the lead. By decreasing, the welding strength may be reduced.
　特許文献４に記載された電池では、外装缶の外部から２段階の連続したエネルギービームを照射し、第１のレーザ出力により、重ね合わせ部材の間の有機物である電解液を排除している。一方、特許文献４には、電解液が外装缶に注入された後、重ね合わせ部材の間に電解液が入り込んだ場合の不都合をなくすことしか開示されていない。 In the battery described in Patent Document 4, the two-stage continuous energy beam is irradiated from the outside of the outer can, and the electrolyte solution that is an organic substance between the overlapping members is excluded by the first laser output. On the other hand, Patent Document 4 discloses only eliminating the inconvenience when the electrolyte enters between the overlapping members after the electrolyte is injected into the outer can.
　本開示は、密閉電池の製造方法及び密閉電池において、外装缶にリードを溶接する際の外装缶を貫通する穴の発生を防ぎ、かつ、安定した溶接強度を得ることを目的とする。 The present disclosure aims to prevent generation of a hole penetrating the outer can when the lead is welded to the outer can and to obtain a stable welding strength in the sealed battery manufacturing method and the sealed battery.
　本開示に係る密閉電池の製造方法は、少なくとも１つの正極と少なくとも１つの負極とがセパレータを介して巻回または積層された電極体と、電極体を収容する有底筒状の外装缶とを含む密閉電池の製造方法であって、外装缶の外部からエネルギービームを照射して、正極及び負極の一方に接続されたリードを外装缶に溶接する溶接工程を備え、溶接工程は、外装缶の外側表面のうち、外装缶の内側表面を介してリードが対向する部分に、外装缶の内部に溶融痕である第１溶融部が留まるように制御された第１エネルギービームを照射する第１照射工程と、第１照射工程後に、外装缶の外側表面のうち第１溶融部が露出している部分の内側に外装缶の外側表面からリードの内部にかけて溶融痕である第２溶融部が形成されるように制御された第２エネルギービームを照射する第２照射工程と、を有する、密閉電池の製造方法である。 A method for manufacturing a sealed battery according to the present disclosure includes an electrode body in which at least one positive electrode and at least one negative electrode are wound or stacked with a separator interposed therebetween, and a bottomed cylindrical outer can that houses the electrode body. A sealed battery manufacturing method comprising: a welding step of irradiating an energy beam from the outside of an outer can and welding a lead connected to one of a positive electrode and a negative electrode to the outer can. First irradiation for irradiating a first energy beam that is controlled so that a first melted portion, which is a melting mark, remains inside the outer can at a portion of the outer surface facing the lead through the inner surface of the outer can. After the step and the first irradiation step, a second molten portion that is a melting mark is formed from the outer surface of the outer can to the inside of the lead inside the portion of the outer surface of the outer can where the first molten portion is exposed. Controlled to It has a second irradiation step of irradiating the second energy beam, and a method of manufacturing a sealed battery.
　本開示に係る密閉電池は、少なくとも１つの正極と少なくとも１つの負極とがセパレータを介して巻回又は積層された電極体と、電極体を収容する有底筒状の外装缶とを備える密閉電池であって、外装缶は、ニッケルめっきされた鉄により形成され、正極及び負極の一方に接続されたリードと外装缶とが、外装缶の外側表面からリードに向けて形成された溶接部で溶接されており、溶接部は、溶融痕である第１溶融部及び第２溶融部を含み、第１溶融部が、外装缶の外側表面から外装缶の厚みの５０～９９％の範囲に形成され、第２溶融部が、外装缶の外側表面からリードの内部にかけて形成され、外装缶の外側から溶接部を見た場合に、第１溶融部の内側にある、密閉電池である。 A sealed battery according to the present disclosure includes an electrode body in which at least one positive electrode and at least one negative electrode are wound or laminated with a separator interposed therebetween, and a bottomed cylindrical outer can that houses the electrode body. The outer can is made of nickel-plated iron, and the lead connected to one of the positive electrode and the negative electrode and the outer can are welded at a weld formed from the outer surface of the outer can toward the lead. The welded portion includes a first melted portion and a second melted portion that are melt marks, and the first melted portion is formed in the range of 50 to 99% of the thickness of the outer can from the outer surface of the outer can. The second melting portion is formed from the outer surface of the outer can to the inside of the lead, and is a sealed battery that is inside the first melting portion when the welded portion is viewed from the outer side of the outer can.
　本開示に係る密閉電池の製造方法及び密閉電池によれば、外装缶にリードを溶接する際の外装缶を貫通する穴の発生を防ぎ、かつ、安定した溶接強度を得ることができる。 According to the method for manufacturing a sealed battery and the sealed battery according to the present disclosure, it is possible to prevent generation of a hole penetrating the outer can when the lead is welded to the outer can, and to obtain a stable welding strength.
実施形態の一例の製造方法により製造された密閉電池の底面側半部の断面図である。It is sectional drawing of the bottom face side half part of the sealed battery manufactured by the manufacturing method of an example of embodiment. 図１に示す密閉電池の底面部である。It is a bottom face part of the sealed battery shown in FIG. 図１のＡ部拡大図である。It is the A section enlarged view of FIG. 図２のＢ部拡大図である。It is the B section enlarged view of FIG. 図３のＣ－Ｃ断面図である。FIG. 4 is a sectional view taken along the line CC of FIG. 3. 実施形態の製造方法において第１エネルギービームを照射する図である。It is a figure which irradiates a 1st energy beam in the manufacturing method of embodiment. 実施形態の製造方法において第２エネルギービームを照射する図である。It is a figure which irradiates a 2nd energy beam in the manufacturing method of embodiment. 実施形態の別例の製造方法において第１エネルギービームを照射する図である。It is a figure which irradiates a 1st energy beam in the manufacturing method of another example of embodiment. 実施形態の別例の密閉電池の底面側半部の断面図である。It is sectional drawing of the bottom face side half part of the sealed battery of another example of embodiment. 図９に示す密閉電池の底面図である。FIG. 10 is a bottom view of the sealed battery shown in FIG. 9.
　以下に、本開示に係る実施の形態について添付図面を参照しながら詳細に説明する。以下の説明において、具体的な形状、材料、数値、方向等は、本開示の理解を容易にするための例示であって、密閉電池の仕様に合わせて適宜変更することができる。また、以下において「略」なる用語は、例えば、完全に同じである場合に加えて、実質的に同じとみなせる場合を含む意味で用いられる。さらに、以下において複数の実施形態、変形例が含まれる場合、それらの特徴部分を適宜に組み合わせて用いることは当初から想定されている。 Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, specific shapes, materials, numerical values, directions, and the like are examples for facilitating understanding of the present disclosure, and can be appropriately changed according to the specifications of the sealed battery. Further, in the following, the term “substantially” is used, for example, in the meaning including the case where it can be considered substantially the same in addition to the case where it is completely the same. Furthermore, when a plurality of embodiments and modifications are included below, it is assumed from the beginning that these characteristic portions are used in appropriate combinations.
　また、以下では、密閉電池が円筒形の非水電解質二次電池である場合を説明するが、密閉電池は、円筒形電池に限定するものではなく、角形電池等であってもよい。また、密閉電池は、以下で説明するような非水電解質二次電池に限定するものではなく、ニッケル水素電池、ニッカド電池等の他の二次電池、または乾電池またはリチウム電池等の一次電池であってもよい。電池が有する電極体は、以下で説明するような巻回型に限定するものではなく、複数の正極と負極がセパレータを介して交互に積層された積層型としてもよい。 In the following, the case where the sealed battery is a cylindrical non-aqueous electrolyte secondary battery will be described. However, the sealed battery is not limited to a cylindrical battery, and may be a prismatic battery or the like. The sealed battery is not limited to a non-aqueous electrolyte secondary battery as described below, and is a secondary battery such as a nickel metal hydride battery or a nickel cadmium battery, or a primary battery such as a dry battery or a lithium battery. May be. The electrode body included in the battery is not limited to the winding type as described below, and may be a stacked type in which a plurality of positive electrodes and negative electrodes are alternately stacked via separators.
　図１は、実施形態の一例の製造方法により製造された密閉電池２０の底面側半部の断面図である。図２は、密閉電池２０の底面図である。図３は、図１のＡ部拡大図である。図４は、図２のＢ部拡大図である。図５は、図３のＣ－Ｃ断面図である。以下では、密閉電池２０は、電池２０と記載する。 FIG. 1 is a cross-sectional view of the bottom half of a sealed battery 20 manufactured by an exemplary manufacturing method of an embodiment. FIG. 2 is a bottom view of the sealed battery 20. FIG. 3 is an enlarged view of a portion A in FIG. FIG. 4 is an enlarged view of a portion B in FIG. 5 is a cross-sectional view taken along the line CC of FIG. Hereinafter, the sealed battery 20 is referred to as a battery 20.
　図１、図２に例示するように、電池２０は、巻回型の電極体２２と、非水電解質（図示せず）と、外装缶５０とを備える。巻回型の電極体２２は、正極２３と、負極２４と、セパレータ２５とを有し、正極２３と負極２４がセパレータ２５を介して積層されるとともに、渦巻状に巻回されている。以下では、電極体２２の軸方向一方側を「上」、軸方向他方側を「下」という場合がある。非水電解質は、非水溶媒と、非水溶媒に溶解したリチウム塩等の電解質塩とを含む。非水電解質は、液体電解質に限定されず、ゲル状ポリマー等を用いた固体電解質であってもよい。 As illustrated in FIGS. 1 and 2, the battery 20 includes a wound electrode body 22, a non-aqueous electrolyte (not shown), and an outer can 50. The wound electrode body 22 includes a positive electrode 23, a negative electrode 24, and a separator 25, and the positive electrode 23 and the negative electrode 24 are stacked via the separator 25 and wound in a spiral shape. Hereinafter, the one axial side of the electrode body 22 may be referred to as “upper” and the other axial side may be referred to as “lower”. The non-aqueous electrolyte includes a non-aqueous solvent and an electrolyte salt such as a lithium salt dissolved in the non-aqueous solvent. The nonaqueous electrolyte is not limited to a liquid electrolyte, and may be a solid electrolyte using a gel polymer or the like.
　正極２３は、帯状の正極集電体２３ａを有し、正極集電体２３ａに正極リード（図示せず）が接続される。正極リードは、正極集電体２３ａを正極端子（図示せず）に電気的に接続するための導電部材であって、電極群の上端から電極体２２の軸方向αの一方側（図１の上方）に延出している。ここで、電極群とは電極体２２において各リードを除く部分を意味する。正極リードは、例えば電極体２２の径方向βの略中央部に設けられている。 The positive electrode 23 has a strip-shaped positive electrode current collector 23a, and a positive electrode lead (not shown) is connected to the positive electrode current collector 23a. The positive electrode lead is a conductive member for electrically connecting the positive electrode current collector 23a to a positive electrode terminal (not shown), and is one side (in FIG. 1) of the electrode body 22 in the axial direction α from the upper end of the electrode group. (Upward). Here, the electrode group means a portion of the electrode body 22 excluding each lead. The positive electrode lead is provided, for example, at a substantially central portion of the electrode body 22 in the radial direction β.
　負極２４は、帯状の負極集電体２４ａを有し、負極集電体２４ａに負極リード２６が接続される。負極リード２６は、負極端子となる外装缶５０に負極集電体２４ａを電気的に接続するための導電部材であって、電極群の巻き終わり側端部の下端から軸方向αの他方側（図１の下方）に延出している。 The negative electrode 24 has a strip-shaped negative electrode current collector 24a, and a negative electrode lead 26 is connected to the negative electrode current collector 24a. The negative electrode lead 26 is a conductive member for electrically connecting the negative electrode current collector 24a to the outer can 50 serving as a negative electrode terminal, and the other end in the axial direction α from the lower end of the winding end side end portion of the electrode group ( It extends in the lower part of FIG.
　各リードの構成材料は特に限定されない。正極リードはアルミニウムを主成分とする金属によって、負極リード２６はニッケルまたは銅を主成分とする金属によって、または、ニッケル及び銅の両方を含む金属によって、それぞれ構成することができる。負極リード２６は、ニッケルめっきされた鉄から形成されてもよい。 The constituent material of each lead is not particularly limited. The positive electrode lead can be composed of a metal mainly composed of aluminum, and the negative electrode lead 26 can be composed of a metal mainly composed of nickel or copper or a metal including both nickel and copper. The negative electrode lead 26 may be formed from nickel-plated iron.
　負極リード２６は、絶縁板３０を介して電極体２２の巻き芯部と対向するように略直角に曲げられて、底板部５１の内面に接する。そして、この状態で、外装缶５０の外部から底板部５１に向けて第１レーザ光４０及び第２レーザ光４１を順に照射することで、外装缶５０と負極リード２６とを溶接部５４により溶接する。溶接部５４は、各レーザ光４０、４１が照射されて溶融、凝固した溶融痕により形成された部分をいう。溶接部５４は、外装缶５０の外側表面から負極リード２６に向けて形成される。第１レーザ光４０は第１エネルギービームに相当し、第２レーザ光４１は第２エネルギービームに相当する。溶接部５４及び溶接工程については後で詳しく説明する。 The negative electrode lead 26 is bent at a substantially right angle so as to face the winding core portion of the electrode body 22 through the insulating plate 30 and is in contact with the inner surface of the bottom plate portion 51. In this state, the outer can 50 and the negative electrode lead 26 are welded by the welded portion 54 by sequentially irradiating the first laser beam 40 and the second laser beam 41 toward the bottom plate portion 51 from the outside of the outer can 50. To do. The welded portion 54 refers to a portion formed by melt marks that are melted and solidified by irradiation with the laser beams 40 and 41. The weld 54 is formed from the outer surface of the outer can 50 toward the negative electrode lead 26. The first laser beam 40 corresponds to a first energy beam, and the second laser beam 41 corresponds to a second energy beam. The weld 54 and the welding process will be described in detail later.
　外装缶５０は、ニッケルめっきされた鉄からなる材料を有底円筒状に加工して形成された容器である。外装缶５０に用いられる鉄は電池特性に悪影響を及ぼさない範囲で異種金属等を含むことができる。 The outer can 50 is a container formed by processing a nickel-plated iron material into a bottomed cylindrical shape. The iron used for the outer can 50 can contain dissimilar metals or the like as long as the battery characteristics are not adversely affected.
　外装缶５０の開口部は、封口体（図示せず）によって封止される。外装缶５０は、電極体２２及び非水電解質を収容する。電極体２２の下部には、絶縁板３０が配置される。負極リード２６は絶縁板３０の外側を通って、外装缶５０の底部側に延び、外装缶５０の底板部５１の内面に溶接される。外装缶５０の底部である底板部５１の厚みは、例えば０．２～０．５ｍｍである。 The opening of the outer can 50 is sealed with a sealing body (not shown). The outer can 50 accommodates the electrode body 22 and the nonaqueous electrolyte. An insulating plate 30 is disposed below the electrode body 22. The negative electrode lead 26 passes through the outside of the insulating plate 30, extends to the bottom side of the outer can 50, and is welded to the inner surface of the bottom plate portion 51 of the outer can 50. The thickness of the bottom plate portion 51 that is the bottom portion of the outer can 50 is, for example, 0.2 to 0.5 mm.
　電極体２２は、正極２３と負極２４がセパレータ２５を介して渦巻状に巻回されてなる巻回構造を有する。正極２３、負極２４、及びセパレータ２５は、いずれも帯状に形成され、渦巻状に巻回されることで電極体２２の径方向βに交互に積層された状態となる。本実施形態では、電極体２２の巻中心軸Ｏを含む巻き芯部２９は、円柱状の空間である。 The electrode body 22 has a winding structure in which a positive electrode 23 and a negative electrode 24 are wound in a spiral shape with a separator 25 interposed therebetween. The positive electrode 23, the negative electrode 24, and the separator 25 are all formed in a band shape, and are wound in a spiral shape to be alternately stacked in the radial direction β of the electrode body 22. In the present embodiment, the winding core portion 29 including the winding center axis O of the electrode body 22 is a cylindrical space.
　正極２３は、正極集電体２３ａ上に形成された正極活物質層を有する。例えば正極集電体２３ａの両面に正極活物質層が形成されている。正極集電体２３ａには、例えばアルミニウムなどの金属の箔、当該金属を表層に配置したフィルム等が用いられる。好適な正極集電体２３ａは、アルミニウムまたはアルミニウム合金を主成分とする金属などの正極の電位範囲で安定な金属の箔である。 The positive electrode 23 has a positive electrode active material layer formed on the positive electrode current collector 23a. For example, the positive electrode active material layer is formed on both surfaces of the positive electrode current collector 23a. As the positive electrode current collector 23a, for example, a metal foil such as aluminum, a film in which the metal is disposed on the surface layer, or the like is used. A suitable positive electrode current collector 23a is a metal foil that is stable in the potential range of the positive electrode such as a metal mainly composed of aluminum or an aluminum alloy.
　正極活物質層は、正極活物質、導電剤、及び結着剤を含むことが好ましい。正極２３は、例えば正極活物質、導電剤、結着剤、及びＮ－メチル－２－ピロリドン（ＮＭＰ）等の溶剤を含む正極合剤スラリーを正極集電体２３ａの両面に塗布した後、乾燥及び圧延することにより作製される。 The positive electrode active material layer preferably contains a positive electrode active material, a conductive agent, and a binder. The positive electrode 23 is formed by, for example, applying a positive electrode mixture slurry containing a positive electrode active material, a conductive agent, a binder, and a solvent such as N-methyl-2-pyrrolidone (NMP) on both surfaces of the positive electrode current collector 23a, and then drying. And it is produced by rolling.
　正極活物質としては、Ｃｏ、Ｍｎ、Ｎｉ等の遷移金属元素を含有するリチウム含有遷移金属酸化物が例示できる。リチウム含有遷移金属酸化物は、特に限定されないが、一般式Ｌｉ１＋ｘＭＯ２（式中、－０．２＜ｘ≦０．２、ＭはＮｉ、Ｃｏ、Ｍｎ、Ａｌの少なくとも１種を含む）で表される複合酸化物であることが好ましい。 Examples of the positive electrode active material include lithium-containing transition metal oxides containing transition metal elements such as Co, Mn, and Ni. The lithium-containing transition metal oxide is not particularly limited, but has the general formula Li 1 + x MO 2 (wherein −0.2 <x ≦ 0.2, M includes at least one of Ni, Co, Mn, and Al) It is preferable that it is complex oxide represented by these.
　上記導電剤の例としては、カーボンブラック（ＣＢ）、アセチレンブラック（ＡＢ）、ケッチェンブラック、黒鉛等の炭素材料などが挙げられる。上記結着剤の例としては、ポリテトラフルオロエチレン（ＰＴＦＥ）、ポリフッ化ビニリデン（ＰＶｄＦ）等のフッ素系樹脂、ポリアクリロニトリル（ＰＡＮ）、ポリイミド（ＰＩ）、アクリル系樹脂、ポリオレフィン系樹脂などが挙げられる。また、これらの樹脂と、カルボキシメチルセルロース（ＣＭＣ）またはその塩、ポリエチレンオキシド（ＰＥＯ）等が併用されてもよい。これらは、１種類を単独で用いてもよく、２種類以上を組み合わせて用いてもよい。 Examples of the conductive agent include carbon materials such as carbon black (CB), acetylene black (AB), ketjen black, and graphite. Examples of the binder include fluorine resins such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), polyimide (PI), acrylic resin, and polyolefin resin. It is done. These resins may be used in combination with carboxymethylcellulose (CMC) or a salt thereof, polyethylene oxide (PEO), and the like. These may be used alone or in combination of two or more.
　負極２４は、負極集電体２４ａ上に形成された負極活物質層を有する。例えば負極集電体２４ａの両面に負極活物質層が形成されている。負極集電体２４ａには、例えばアルミニウムや銅などの負極の電位範囲で安定な金属の箔、当該金属を表層に配置したフィルム等が用いられる。 The negative electrode 24 has a negative electrode active material layer formed on the negative electrode current collector 24a. For example, the negative electrode active material layer is formed on both surfaces of the negative electrode current collector 24a. For the negative electrode current collector 24a, for example, a metal foil that is stable in the potential range of a negative electrode such as aluminum or copper, or a film in which the metal is disposed on the surface layer is used.
　負極活物質層は、負極集電体２４ａの両面において、後述の無地部を除く全域に形成されることが好適である。負極活物質層は、負極活物質及び結着剤を含むことが好ましい。負極活物質層は、必要により導電剤を含んでいてもよい。負極２４は、例えば負極活物質、結着剤、及び水等を含む負極合剤スラリーを負極集電体２４ａの両面に塗布した後、乾燥及び圧延することにより作製される。 It is preferable that the negative electrode active material layer is formed on both sides of the negative electrode current collector 24a over the entire area excluding a solid portion described later. The negative electrode active material layer preferably contains a negative electrode active material and a binder. The negative electrode active material layer may contain a conductive agent as necessary. The negative electrode 24 is produced, for example, by applying a negative electrode mixture slurry containing a negative electrode active material, a binder, water, and the like to both surfaces of the negative electrode current collector 24a, followed by drying and rolling.
　負極活物質としては、リチウムイオンを可逆的に吸蔵、放出できるものであれば特に限定されず、例えば天然黒鉛、人造黒鉛等の炭素材料、Ｓｉ、Ｓｎ等のリチウムと合金化する金属、またはこれらを含む合金、複合酸化物などを用いることができる。負極活物質層に含まれる結着剤には、例えば正極２３の場合と同様の樹脂が用いられる。水系溶媒で負極合剤スラリーを調製する場合は、スチレン－ブタジエンゴム（ＳＢＲ）、ＣＭＣまたはその塩、ポリアクリル酸またはその塩、ポリビニルアルコール等を用いることができる。これらは、１種類を単独で用いてもよく、２種類以上を組み合わせて用いてもよい。 The negative electrode active material is not particularly limited as long as it can reversibly occlude and release lithium ions. For example, carbon materials such as natural graphite and artificial graphite, metals such as Si and Sn, alloys with lithium, or these An alloy, a composite oxide, or the like containing can be used. As the binder contained in the negative electrode active material layer, for example, the same resin as that of the positive electrode 23 is used. When preparing the negative electrode mixture slurry with an aqueous solvent, styrene-butadiene rubber (SBR), CMC or a salt thereof, polyacrylic acid or a salt thereof, polyvinyl alcohol, or the like can be used. These may be used alone or in combination of two or more.
　負極２４には、負極集電体２４ａの表面が露出した無地部が設けられる。無地部は、負極リード２６が接続される部分であって、負極集電体２４ａの表面が負極活物質層に覆われていない部分である。無地部は、負極２４の幅方向である軸方向αに沿って長く延びた正面視略矩形形状であり、負極リード２６よりも幅広に形成される。 The negative electrode 24 is provided with a plain portion where the surface of the negative electrode current collector 24a is exposed. The plain portion is a portion to which the negative electrode lead 26 is connected, and the surface of the negative electrode current collector 24a is not covered with the negative electrode active material layer. The plain portion has a substantially rectangular shape in front view extending long along the axial direction α which is the width direction of the negative electrode 24, and is formed wider than the negative electrode lead 26.
　負極リード２６は、負極集電体２４ａの表面に例えば超音波溶接等により接合されている。なお、負極２４の巻き終わり側端部だけでなく、巻き方向中間部、及び巻き始め側端部等に、負極リード２６とは別の負極リードを設けて、電極群から底板部５１側に延出させ、その延出させた負極リードを巻き芯部で負極リード２６に重ねて、レーザ光の照射により外装缶５０と溶接することもできる。負極リードを負極２４の複数位置に設けることで、集電性が向上する。無地部は、例えば負極集電体２４ａの一部に負極合剤スラリーを塗布しない間欠塗布により設けられる。 The negative electrode lead 26 is joined to the surface of the negative electrode current collector 24a by, for example, ultrasonic welding. It should be noted that a negative electrode lead different from the negative electrode lead 26 is provided not only at the winding end side end portion of the negative electrode 24 but also at the winding direction intermediate portion and the winding start side end portion, and extends from the electrode group to the bottom plate portion 51 side. The extended negative electrode lead can be overlapped on the negative electrode lead 26 at the winding core and welded to the outer can 50 by laser light irradiation. By providing the negative electrode lead at a plurality of positions of the negative electrode 24, the current collecting property is improved. The plain portion is provided, for example, by intermittent application without applying the negative electrode mixture slurry to a part of the negative electrode current collector 24a.
　正極リードは、正極集電体２３ａに形成された無地部に接合され、正極集電体２３ａから上方に突出した部分が正極端子または正極端子に接続された部分に接合される。 The positive electrode lead is bonded to a plain portion formed on the positive electrode current collector 23a, and a portion protruding upward from the positive electrode current collector 23a is bonded to a positive electrode terminal or a portion connected to the positive electrode terminal.
　セパレータ２５には、イオン透過性及び絶縁性を有する多孔性シートが用いられる。多孔性シートの具体例としては、微多孔薄膜、織布、不織布などが挙げられる。セパレータ２５の材質としては、ポリエチレン、ポリプロピレン等のオレフィン樹脂が好ましい。 As the separator 25, a porous sheet having ion permeability and insulating properties is used. Specific examples of the porous sheet include a microporous thin film, a woven fabric, and a non-woven fabric. As a material of the separator 25, an olefin resin such as polyethylene and polypropylene is preferable.
　溶接部５４は、上記のように溶融痕により形成される。外装缶５０の底板部５１の外側（図１の下側）から溶接部５４を見た場合に、図４に示すように、第２溶融部５８は、全周を囲まれるように第１溶融部５６の内側にあり、かつ、外装缶５０の外側表面に露出する。第２溶融部５８は、この状態で、外装缶５０と負極リード２６(図３)とを溶接している。第２溶融部５８は、第１溶融部５６より深く形成される。 The weld 54 is formed by melting marks as described above. As shown in FIG. 4, when the welded portion 54 is viewed from the outside (the lower side of FIG. 1) of the bottom plate portion 51 of the outer can 50, the second melting portion 58 is first melted so as to surround the entire circumference. It is inside the portion 56 and exposed on the outer surface of the outer can 50. In this state, the second melting part 58 welds the outer can 50 and the negative electrode lead 26 (FIG. 3). The second melting part 58 is formed deeper than the first melting part 56.
　第１溶融部５６は、外装缶５０の内部に留まるように形成されている。第１溶融部５６は、後述の第１照射工程で、第１レーザ光４０を外装缶５０の外部から底板部５１に向かって照射させることにより形成される。第２溶融部５８は、後述のように第１照射工程の後の第２照射工程で第２レーザ光４１を外装缶５０の外部から底板部５１に向かって照射させることにより形成される。 The first melting part 56 is formed so as to remain inside the outer can 50. The first melting portion 56 is formed by irradiating the first laser light 40 from the outside of the outer can 50 toward the bottom plate portion 51 in a first irradiation step described later. The second melting part 58 is formed by irradiating the second laser light 41 from the outside of the outer can 50 toward the bottom plate part 51 in the second irradiation process after the first irradiation process, as will be described later.
　図４に示すように、第１溶融部５６は、外装缶５０の底板部５１の外側から見た場合の平面形状が直線状である。そして、第２溶融部５８も、底板部５１の外側から見た場合の平面形状が直線状であり、第２溶融部５８の幅ｗ２は第１溶融部５６の幅ｗ１より小さい。また、第２溶融部５８は、第１溶融部５６よりニッケルの含有濃度（質量％）が高い。なお、第１溶融部５６及び第２溶融部５８の存在は、例えば、外装缶５０の外側から観察することにより確認できる。これに加えて、第１溶融部５６及び第２溶融部５８の存在は、例えば溶融痕の外装缶５０の厚み方向における断面を光学顕微鏡等により観察することで確認することができる。 As shown in FIG. 4, the first melting part 56 has a linear planar shape when viewed from the outside of the bottom plate part 51 of the outer can 50. The second melting part 58 also has a linear shape when viewed from the outside of the bottom plate part 51, and the width w <b> 2 of the second melting part 58 is smaller than the width w <b> 1 of the first melting part 56. The second melting part 58 has a higher nickel content (mass%) than the first melting part 56. In addition, presence of the 1st fusion | melting part 56 and the 2nd fusion | melting part 58 can be confirmed by observing from the outer side of the armored can 50, for example. In addition, the presence of the first melting part 56 and the second melting part 58 can be confirmed by observing, for example, an optical microscope or the like in the thickness direction of the outer can 50 of the melt mark.
　各レーザ光としては、ファイバーレーザのレーザ光を用いることが好適である。ファイバーレーザのスポット径は、例えば直径が０．０２ｍｍ～０．０５ｍｍ程度と非常に小さくすることができるため、そのファイバーレーザにより形成される溶融痕の幅も約０．１ｍｍと非常に小さくできる。このため、レーザ光の集光点のパワー密度を非常に高くできる。第２レーザ光４１は、第２レーザ光４１の照射により形成された溶融痕が外装缶５０を貫通するが、負極リード２６を貫通しないように照射する。 It is preferable to use a fiber laser beam as each laser beam. The spot diameter of the fiber laser can be made very small, for example, about 0.02 mm to 0.05 mm, so that the width of the melt mark formed by the fiber laser can be made very small, about 0.1 mm. For this reason, the power density of the condensing point of a laser beam can be made very high. The second laser light 41 is irradiated so that melt marks formed by the irradiation of the second laser light 41 penetrate the outer can 50 but not the negative electrode lead 26.
　第１溶融部５６を形成する際の第１レーザ光４０のスポット径は、第２レーザ光４１のスポット径より大きくすることが好ましい。第１レーザ光４０は、第１レーザ光４０の照射により形成された溶融痕が外装缶５０を貫通せず、負極リード２６に達しないように照射する。このとき、例えば、直線方向に沿って一方側（例えば図１の右側）に向かって、第１レーザ光４０の照射部を外装缶５０の底板部５１の外側表面において移動させて、第１溶融部５６を形成する。第２レーザ光４１によって形成される第２溶融部５８は、第１レーザ光４０の照射により形成された第１溶融部５６の内側に形成される。 It is preferable that the spot diameter of the first laser beam 40 when forming the first melting part 56 is larger than the spot diameter of the second laser beam 41. The first laser beam 40 is irradiated so that melt marks formed by the irradiation of the first laser beam 40 do not penetrate the outer can 50 and do not reach the negative electrode lead 26. At this time, for example, the irradiation portion of the first laser light 40 is moved on the outer surface of the bottom plate portion 51 of the outer can 50 along one direction (for example, the right side in FIG. 1) along the linear direction, and the first melting is performed. A portion 56 is formed. The second melting part 58 formed by the second laser light 41 is formed inside the first melting part 56 formed by irradiation with the first laser light 40.
　また、電池２０をレーザ光の照射方向に対し直交する方向に相対的に移動させることで、レーザ光による溶接部５４が底板部５１の外側から見た場合に線状となりやすい。このとき、電池２０は底板部５１を上にした状態で配置し、その底部に向けてレーザ光を照射させることができる。電池２０を横に傾けた状態で配置し、底板部５１に向けてレーザ光を照射させることもできる。 Further, by moving the battery 20 relatively in the direction orthogonal to the laser light irradiation direction, the welded portion 54 by the laser light is likely to be linear when viewed from the outside of the bottom plate portion 51. At this time, the battery 20 can be arranged with the bottom plate portion 51 facing upward, and laser light can be irradiated toward the bottom portion. It is also possible to arrange the battery 20 in a state where it is tilted sideways and irradiate the bottom plate portion 51 with laser light.
　次に、外装缶５０の外部からエネルギービームの一例であるレーザ光を照射して、外装缶５０と負極リード２６とを溶接する溶接工程を含む実施形態の電池の製造方法を説明する。この製造方法において、溶接工程は、第１照射工程と、第２照射工程とを有する。第１照射工程及び第２照射工程は、外装缶５０に電解質を注入する前に行う。図６は、実施形態の製造方法において、第１照射工程で第１レーザ光４０を照射する図である。図７は、実施形態の製造方法において、第２照射工程で第２レーザ光４１を照射する図である。 Next, a battery manufacturing method according to an embodiment including a welding process of welding the outer can 50 and the negative electrode lead 26 by irradiating a laser beam as an example of an energy beam from the outside of the outer can 50 will be described. In this manufacturing method, the welding process includes a first irradiation process and a second irradiation process. The first irradiation step and the second irradiation step are performed before injecting the electrolyte into the outer can 50. FIG. 6 is a diagram in which the first laser beam 40 is irradiated in the first irradiation step in the manufacturing method of the embodiment. FIG. 7 is a diagram for irradiating the second laser light 41 in the second irradiation step in the manufacturing method of the embodiment.
　第１照射工程を行う前には、外装缶５０の底板部５１の内面に負極リード２６を対向させた状態で、外装缶５０に電極体２２を収容する。そして、この状態で、第１照射工程及び第２照射工程により、外装缶５０の外部から底板部５１に向けて２段階でレーザ光を照射する。具体的には、図６に示すように、第１溶融部５６を形成する第１レーザ光４０を照射する前に、外装缶５０の内側に上から押さえ棒７０を挿入し、押さえ棒７０により絶縁板３０を介して負極リード２６を上側から押圧する。これにより、外装缶５０と負極リード２６を密着させた状態とし、その状態で、底板部５１の外側表面のうち、底板部５１の内側表面を介して負極リード２６が対向する部分に、第１エネルギー量を有する第１レーザ光４０を照射して、第１溶融部５６を形成する。このとき、溶融痕である第１溶融部５６が、第１レーザ光４０の照射位置において外装缶５０を貫通せず、外装缶５０の内部に留まり、負極リード２６に達しないように、第１レーザ光４０が制御される。このとき、第１レーザ光４０のスポット径は、後述の第２レーザ光４１のスポット径より大きくすることが好ましい。また、直線方向に沿って一方側（例えば図６の右側）に向かって、第１レーザ光４０の照射部を外装缶５０の底板部５１の外側表面において移動させる。このとき、電池２０をレーザ光の照射方向に対し直交する方向に相対的に移動させるように、レーザ光の光源を移動させる。本実施形態では、押さえ棒７０により絶縁板３０を介して負極リード２６を押圧したが、絶縁板３０の中央部に穴を設けて、その穴を貫通した押さえ棒が直接負極リード２６を押圧してもよい。 Before performing the first irradiation step, the electrode body 22 is accommodated in the outer can 50 with the negative electrode lead 26 facing the inner surface of the bottom plate portion 51 of the outer can 50. In this state, laser light is irradiated in two stages from the outside of the outer can 50 toward the bottom plate portion 51 by the first irradiation process and the second irradiation process. Specifically, as shown in FIG. 6, before irradiating the first laser beam 40 that forms the first melting portion 56, a presser bar 70 is inserted into the outer can 50 from above, and is pressed by the presser bar 70. The negative electrode lead 26 is pressed from above through the insulating plate 30. As a result, the outer can 50 and the negative electrode lead 26 are brought into close contact with each other, and in this state, a portion of the outer surface of the bottom plate portion 51 facing the negative electrode lead 26 through the inner surface of the bottom plate portion 51 is first. Irradiation with a first laser beam 40 having an energy amount forms the first melted portion 56. At this time, the first melting portion 56 that is a melting mark does not penetrate the outer can 50 at the irradiation position of the first laser light 40, stays inside the outer can 50, and does not reach the negative electrode lead 26. The laser beam 40 is controlled. At this time, it is preferable that the spot diameter of the first laser light 40 is larger than the spot diameter of the second laser light 41 described later. Moreover, the irradiation part of the 1st laser beam 40 is moved in the outer surface of the bottom plate part 51 of the armored can 50 toward one side (for example, the right side of FIG. 6) along the linear direction. At this time, the light source of the laser light is moved so that the battery 20 is relatively moved in a direction orthogonal to the irradiation direction of the laser light. In this embodiment, the negative electrode lead 26 is pressed by the presser bar 70 through the insulating plate 30. However, a hole is provided in the central portion of the insulating plate 30 and the presser bar penetrating the hole directly presses the negative electrode lead 26. May be.
　次いで、第２照射工程では、図７に示すように、第２溶融部５８を形成する第２レーザ光４１を照射する前に、第１照射工程の場合と同様に、押さえ棒７０により外装缶５０と負極リード２６を密着させた状態とする。そして、その状態で、底板部５１に向けて外側から第２エネルギー量を有する第２レーザ光４１を第１溶融部５６が露出している部分の内側に照射して、第２溶融部５８を形成する。このとき、底板部５１の外側表面から負極リード２６の内部にかけて溶融痕である第２溶融部が形成されるように第２レーザ光４２が制御される。このとき、例えば、上記の直線方向に沿って一方側（例えば図７の右側）に向かって、第２レーザ光４１の照射部を外装缶５０の底板部５１の外側表面において移動させて、第２溶融部５８を形成する。第２溶融部５８は、第１レーザ光４０の照射により形成された溶融痕の内側の範囲で、外装缶５０と負極リード２６の一部を溶融するように形成される。第１溶融部５６の一部は溶融、凝固して第２溶融部５８に変化しており、第２溶融部５８は、第１溶融部５６のうち第２溶融部５８に変化せずに残った部分に隣接するように形成される。第２照射工程においても、第１照射工程と同様に、電池２０をレーザ光の照射方向に対し直交する方向に相対的に移動させるように、レーザ光の光源を移動させる。 Next, in the second irradiation step, as shown in FIG. 7, before the second laser beam 41 for forming the second melting portion 58 is irradiated, the outer canister is pressed by the presser bar 70 in the same manner as in the first irradiation step. 50 and the negative electrode lead 26 are brought into close contact with each other. In this state, the second laser beam 41 having the second energy amount is irradiated from the outside toward the bottom plate portion 51 to the inside of the portion where the first melting portion 56 is exposed, and the second melting portion 58 is irradiated. Form. At this time, the second laser beam 42 is controlled so that a second melted portion that is a melt mark is formed from the outer surface of the bottom plate portion 51 to the inside of the negative electrode lead 26. At this time, for example, the irradiation part of the second laser light 41 is moved on the outer surface of the bottom plate part 51 of the outer can 50 along one of the linear directions (for example, the right side in FIG. 7). 2 to form the melted portion 58. The second melting part 58 is formed so as to melt a part of the outer can 50 and the negative electrode lead 26 in the range inside the melt mark formed by the irradiation of the first laser beam 40. A part of the first melting part 56 is melted and solidified to be changed into the second melting part 58, and the second melting part 58 remains without changing to the second melting part 58 in the first melting part 56. It is formed adjacent to the part. Also in the second irradiation step, similarly to the first irradiation step, the laser light source is moved so that the battery 20 is relatively moved in the direction orthogonal to the laser light irradiation direction.
　上記のように押さえ棒７０により外装缶５０と負極リード２６を密着させた状態で、外装缶５０の外側から第１レーザ光４０を照射して、外装缶５０と負極リード２６を溶接するので、電池２０の内部にスパッタが発生することを防止しやすい。 As described above, the outer can 50 and the negative electrode lead 26 are welded by irradiating the first laser beam 40 from the outside of the outer can 50 in a state where the outer can 50 and the negative electrode lead 26 are in close contact with each other by the holding rod 70. It is easy to prevent spatter from occurring inside the battery 20.
　第２溶融部５８は、底板部５１の外側表面の第１溶融部５６の内側に形成され、底板部５１の内側（図１の上側）方向に延びる第１溶融部５６と第２溶融部５８との境界は、底板部５１の内部に位置する。上記のように第１レーザ光４０及び第２レーザ光４１は、照射部が底板部５１の外側表面上を同一の直線方向に沿って移動するように照射する。これによって、第１溶融部５６及び第２溶融部５８の底板部５１の外側から見た場合の平面形状が直線状に形成される。また、底板部５１の外側から見た場合に、第２溶融部５８の全部は第１溶融部５６により囲まれることが好ましい。なお、レーザ光の照射部は外装缶５０の外側表面に対して相対的に移動させればよく、レーザ光及び外装缶５０のうち、実際に動かすのは外装缶５０でもよい。 The second melting part 58 is formed inside the first melting part 56 on the outer surface of the bottom plate part 51, and extends in the inner side (upper side in FIG. 1) direction of the bottom plate part 51 and the second melting part 58. Is located inside the bottom plate portion 51. As described above, the first laser beam 40 and the second laser beam 41 are irradiated so that the irradiation unit moves on the outer surface of the bottom plate unit 51 along the same linear direction. Thereby, the planar shape when viewed from the outside of the bottom plate part 51 of the first melting part 56 and the second melting part 58 is formed in a straight line. Further, when viewed from the outside of the bottom plate portion 51, it is preferable that the entire second melting portion 58 is surrounded by the first melting portion 56. In addition, the irradiation part of a laser beam should just move relatively with respect to the outer surface of the armored can 50, and the armored can 50 may be actually moved among laser light and the armored can 50.
　上記の実施形態の電池の製造方法及び電池２０によれば、外装缶５０に電解質が注入される前の状態で、外装缶５０に負極リード２６を溶接する際の外装缶５０を貫通する穴の発生を防ぎ、かつ、安定した溶接強度を得ることができる。具体的には、第１溶融部５６を形成する第１レーザ光４０を底板部５１に照射することで外装缶５０と負極リード２６の間に樹脂が存在する場合に、その樹脂が昇華等で気化する。これにより、外装缶５０と負極リード２６の間に樹脂が存在しない状態で、第２溶融部５８を形成する第２レーザ光４１を第１溶融部５６の内側に照射し、外装缶５０と負極リード２６を溶接することができる。このため、外装缶５０を貫通する穴の発生を防ぐことができるとともに、外装缶５０において貫通しない凹部の発生を抑制できるので、外装缶５０の内面で負極リード２６と対向する部分での凹部の発生を抑制でき、安定した溶接強度を得ることができる。
ことができる。 According to the battery manufacturing method and the battery 20 of the above embodiment, the holes penetrating the outer can 50 when welding the negative electrode lead 26 to the outer can 50 in a state before the electrolyte is injected into the outer can 50. Generation | occurrence | production can be prevented and stable welding strength can be obtained. Specifically, when resin is present between the outer can 50 and the negative electrode lead 26 by irradiating the first laser beam 40 forming the first melting portion 56 to the bottom plate portion 51, the resin is sublimated or the like. Vaporize. Thus, the second laser beam 41 that forms the second melting portion 58 is irradiated to the inside of the first melting portion 56 in a state where no resin exists between the outer can 50 and the negative electrode lead 26, and the outer can 50 and the negative electrode The lead 26 can be welded. For this reason, generation | occurrence | production of the hole which penetrates the armored can 50 can be prevented, and generation | occurrence | production of the recessed part which does not penetrate in the armored can 50 can be suppressed, Therefore The recessed part in the part which opposes the negative electrode lead 26 in the inner surface of the exterior can 50 Generation | occurrence | production can be suppressed and stable welding strength can be obtained.
be able to.
　さらに、上記の電池２０は、溶接部５４が図１、図２に示す第１溶融部５６と第２溶融部５８を含むため、溶接部５４に起因する底板部５１での応力腐食割れが生じにくくなる。 Further, in the battery 20 described above, since the welded portion 54 includes the first melted portion 56 and the second melted portion 58 shown in FIGS. 1 and 2, stress corrosion cracking in the bottom plate portion 51 caused by the welded portion 54 occurs. It becomes difficult.
　図８は、実施形態の別例の製造方法において第１レーザ光４０を照射する図である。本例の製造方法では、第１照射工程で第１溶融部５６を形成する第１レーザ光４０を底板部５１の外側表面に照射する際に、外装缶５０と負極リード２６との間に隙間Ｓ１をあけている。このときには、図６に示した製造方法の場合と異なり、第１レーザ光４０を照射する際に、外装缶５０の内側には、上から押さえ棒を挿入せず、負極リード２６を上側から押圧することは行わない。 FIG. 8 is a diagram of irradiating the first laser beam 40 in another manufacturing method according to the embodiment. In the manufacturing method of this example, when the first laser beam 40 that forms the first melting portion 56 is irradiated to the outer surface of the bottom plate portion 51 in the first irradiation step, there is a gap between the outer can 50 and the negative electrode lead 26. S1 is opened. At this time, unlike the manufacturing method shown in FIG. 6, when the first laser beam 40 is irradiated, the pressing rod is not inserted into the outer can 50 from the upper side, and the negative electrode lead 26 is pressed from the upper side. Do not do.
　外装缶５０と負極リード２６の間に形成する隙間Ｓ１は、０．００５ｍｍ～０．２ｍｍ程度あればよい。隙間Ｓ１が存在することにより、第１レーザ光４０が照射されたことで発せられた熱が外装缶５０の中に留まり、負極リード２６や、外装缶５０と負極リード２６を密着させる押さえ棒に熱が吸収されることがない。このため、外装缶５０と負極リード２６の間に存在する樹脂が効率よく気化する。その後、図７に示した製造方法と同様に、第２溶融部５８を形成する第２レーザ光４１を底板部５１に照射する際には、押さえ棒７０によって外装缶５０と負極リード２６を密着させ、その状態で外装缶５０と負極リード２６を溶接する。 The gap S1 formed between the outer can 50 and the negative electrode lead 26 may be about 0.005 mm to 0.2 mm. Due to the presence of the gap S1, the heat generated by the irradiation of the first laser beam 40 stays in the outer can 50, and the negative electrode lead 26 or the pressing rod that closely contacts the outer can 50 and the negative electrode lead 26. Heat is not absorbed. For this reason, the resin existing between the outer can 50 and the negative electrode lead 26 is efficiently vaporized. After that, as in the manufacturing method shown in FIG. 7, when the second laser beam 41 that forms the second melting portion 58 is irradiated to the bottom plate portion 51, the outer can 50 and the negative electrode lead 26 are brought into close contact with the pressing rod 70. In this state, the outer can 50 and the negative electrode lead 26 are welded.
　また、第１溶融部５６を形成する第１レーザ光４０のレーザスポット径は、第２溶融部５８を形成する第２レーザ光４１のレーザスポット径より大きいほうが良い。第１レーザ光４０は、外装缶５０と負極リード２６の間に存在する樹脂を熱によって気化させるために照射するので、第２溶融部５８を形成する領域よりも広い領域で樹脂を気化し除去することが好ましい。言い換えると、第２レーザ光４１は、第１レーザ光４０によって外装缶５０と負極リード２６の間に存在する樹脂を除去された領域に照射されることで、第２溶融部５８を形成し、外装缶５０と負極リード２６とを溶接する。これにより、外装缶５０を貫通する穴の発生を防ぐことができ、かつ安定した溶接強度を得ることができる。 Also, the laser spot diameter of the first laser beam 40 that forms the first melting part 56 is preferably larger than the laser spot diameter of the second laser beam 41 that forms the second melting part 58. Since the first laser beam 40 is irradiated so that the resin existing between the outer can 50 and the negative electrode lead 26 is vaporized by heat, the resin is vaporized and removed in a region wider than the region where the second melting portion 58 is formed. It is preferable to do. In other words, the second laser light 41 is irradiated to the area where the resin existing between the outer can 50 and the negative electrode lead 26 is removed by the first laser light 40, thereby forming the second melting portion 58, The outer can 50 and the negative electrode lead 26 are welded. Thereby, generation | occurrence | production of the hole which penetrates the armored can 50 can be prevented, and stable welding strength can be obtained.
　また、各レーザ光としてファイバーレーザを用いた場合には、第１レーザ光４０及び第２レーザ光４１の照射深度と、第１レーザ光４０の照射面積とを精度よく制御できる。これにより、第１溶融部５６及び第２溶融部５８の寸法（厚み、幅、長さ）を精度よく制御できるとともに、外装缶５０と負極リード２６の間に存在する樹脂を効率的に気化し除去できる。なお、外装缶５０の外側から溶接部５４を見た場合における第１溶融部５６及び第２溶融部５８の平面形状は線状であればよく、直線状に限定するものではない。例えば、第１溶融部５６及び第２溶融部５８の平面形状は、曲線状としてもよい。 Further, when a fiber laser is used as each laser beam, the irradiation depth of the first laser beam 40 and the second laser beam 41 and the irradiation area of the first laser beam 40 can be controlled with high accuracy. Accordingly, the dimensions (thickness, width, length) of the first melting part 56 and the second melting part 58 can be controlled with high accuracy, and the resin existing between the outer can 50 and the negative electrode lead 26 can be efficiently vaporized. Can be removed. In addition, the planar shape of the 1st fusion | melting part 56 and the 2nd fusion | melting part 58 at the time of seeing the welding part 54 from the outer side of the armored can 50 should just be linear, and is not limited to linear form. For example, the planar shapes of the first melting part 56 and the second melting part 58 may be curved.
　次に、上記の実施形態の効果を確認するために行った実験結果を説明する。実験には、以下の実施例１、２及び比較例の電池の製造方法のそれぞれで作製された電池を用いた。 Next, the results of experiments conducted to confirm the effects of the above embodiment will be described. In the experiment, batteries manufactured by the following battery manufacturing methods of Examples 1 and 2 and Comparative Example were used.
［実施例１］
　実施例１の構成の寸法を例示するが、本開示は以下の寸法に限定されるものではない。図４を参照して、第１溶融部５６を外装缶５０の外側から見た場合の短尺方向の幅ｗ１が、第２溶融部５８を外装缶５０の外側から見た場合の短尺方向の幅ｗ２より大きく、かつ、幅ｗ２の３倍以下である。また、第１溶融部５６を外装缶５０の外側から見た場合の長尺方向の長さＬ１は、第２溶融部５８を外装缶５０の外側から見た場合の長尺方向の長さＬ２より大きく、かつ、長さＬ２の２倍以下である。また、図３を参照して、第１溶融部５６の厚みＤ１は、外装缶５０の厚みＤｃの０．５～０．９９倍である。 [Example 1]
Although the dimension of the structure of Example 1 is illustrated, this indication is not limited to the following dimensions. With reference to FIG. 4, the width w <b> 1 in the short direction when the first melting portion 56 is viewed from the outside of the outer can 50 is the width in the short direction when the second melting portion 58 is viewed from the outside of the outer can 50. It is larger than w2 and not more than 3 times the width w2. The length L1 in the longitudinal direction when the first melting portion 56 is viewed from the outside of the outer can 50 is the length L2 in the longitudinal direction when the second melting portion 58 is viewed from the outside of the outer can 50. It is larger and not more than twice the length L2. Referring to FIG. 3, the thickness D1 of the first melting portion 56 is 0.5 to 0.99 times the thickness Dc of the outer can 50.
　より具体的な寸法として、外装缶５０はニッケルめっきした鉄からなり、外側表面のニッケルめっき層は厚みが３．５μｍである。また、外装缶５０のニッケルめっき層を含む総厚みは、３００μｍである。さらに、溶接部５４の第１溶融部５６及び第２溶融部５８の寸法は以下の通りである。
（第１溶融部５６）
（１）外装缶５０の外側から見た場合の短尺方向の幅ｗ１：１７０μｍ
（２）外装缶５０の外側から見た場合の長尺方向の長さＬ１：１６００μｍ
（３）厚み(外装缶５０の外側表面から第１溶融部５６の形成された長さ)Ｄ１：２７０μｍ
（第２溶融部５８）
（１）外装缶５０の外側から見た場合の短尺方向の幅ｗ２：８０μｍ
（２）外装缶５０の外側から見た場合の長尺方向の長さＬ２：１０００μｍ
（３）厚み（外装缶５０の外側表面から負極リード２６の内部における末端までの長さ）Ｄ２：３５０μｍ More specifically, the outer can 50 is made of nickel-plated iron, and the nickel plating layer on the outer surface has a thickness of 3.5 μm. The total thickness of the outer can 50 including the nickel plating layer is 300 μm. Furthermore, the dimension of the 1st fusion | melting part 56 of the welding part 54 and the 2nd fusion | melting part 58 is as follows.
(First melting part 56)
(1) Width w1: 170 μm in the short direction when viewed from the outside of the outer can 50
(2) Length L1 in the longitudinal direction when viewed from the outside of the outer can 50: 1600 μm
(3) Thickness (the length at which the first melted portion 56 is formed from the outer surface of the outer can 50) D1: 270 μm
(Second melting part 58)
(1) Width w2 in the short direction when viewed from the outside of the outer can 50: 80 μm
(2) Length L2 in the long direction when viewed from the outside of the outer can 50: 1000 μm
(3) Thickness (length from the outer surface of the outer can 50 to the terminal inside the negative electrode lead 26) D2: 350 μm
　実施例１の製造方法では、外装缶５０と負極リード２６の間には、実施形態の効果を確認するために、一般的な設備潤滑油を塗布した。その後、第１照射工程で、押さえ棒７０(図６)によって外装缶５０と負極リード２６を密着させた状態で、第１溶融部５６を形成する第１レーザ光４０を外装缶５０の外側から底板部５１に照射した。その後に、第２照射工程で、押さえ棒７０(図７)によって外装缶５０と負極リード２６を密着させた状態で、第２溶融部５８を形成する第２レーザ光４１を照射することにより、外装缶５０と負極リード２６を溶接した。 In the manufacturing method of Example 1, a general facility lubricating oil was applied between the outer can 50 and the negative electrode lead 26 in order to confirm the effect of the embodiment. Thereafter, in the first irradiation step, the first laser beam 40 that forms the first melting portion 56 is emitted from the outside of the outer can 50 in a state where the outer can 50 and the negative electrode lead 26 are brought into close contact with the pressing rod 70 (FIG. 6). The bottom plate part 51 was irradiated. After that, in the second irradiation step, by irradiating the second laser beam 41 that forms the second melting portion 58 in a state where the outer can 50 and the negative electrode lead 26 are brought into close contact with the pressing rod 70 (FIG. 7), The outer can 50 and the negative electrode lead 26 were welded.
　第１レーザ光４０及び第２レーザ光４１の照射条件は以下の通りである。
（第１レーザ光４０）
（１）エネルギー：１．４４Ｊ
（２）レーザスポット径：１７０μｍ
（３）移動速度：４７０ｍｍ／ｓｅｃ
（第２レーザ光４１）
（１）エネルギー：０．６Ｊ
（２）レーザスポット径：２０μｍ
（３）移動速度：４７０ｍｍ／ｓｅｃ The irradiation conditions of the first laser beam 40 and the second laser beam 41 are as follows.
(First laser beam 40)
(1) Energy: 1.44J
(2) Laser spot diameter: 170 μm
(3) Movement speed: 470 mm / sec
(Second laser beam 41)
(1) Energy: 0.6J
(2) Laser spot diameter: 20 μm
(3) Movement speed: 470 mm / sec
　上記の条件で実施例１において、溶接部５４を形成したところ、第１レーザ光４０の照射によって、外装缶５０内部に溶融痕が形成された。その溶融痕は、外装缶５０の外側表面における短尺方向の幅が１７０μｍで、長尺方向の長さが１６００μｍで、厚み(外装缶５０の外側表面から第１溶融部５６の形成された長さ)が２７０μｍであった。続いて第２レーザ光４１の照射によって、第１レーザ光４０の照射で外装缶５０に溶融痕の内側に、短尺方向の幅が８０μｍで、長尺方向の長さが１０００μｍで、厚み(外装缶５０の外側表面から第２溶融部５８の形成された長さ)３５０μｍの溶融痕が形成された。 When the weld 54 was formed in Example 1 under the above conditions, melt marks were formed inside the outer can 50 by irradiation with the first laser light 40. The melt mark has a width in the short direction of 170 μm on the outer surface of the outer can 50, a length in the long direction of 1600 μm, and a thickness (the length from which the first melting portion 56 is formed from the outer surface of the outer can 50. ) Was 270 μm. Subsequently, by irradiation with the second laser light 41, the width of the short direction is 80 μm, the length in the long direction is 1000 μm, the thickness (exterior) The length of the second melted portion 58 formed from the outer surface of the can 50 was 350 μm.
［実施例２］
　実施例２は、図８に示した実施形態の別例の製造方法に対応する。実施例２の電池の構成及び寸法は、実施例１と同様である。実施例２の製造方法では、実施例１と同様に、外装缶５０と負極リード２６の間に、一般的な設備潤滑油を塗布した。その後、実施例２では、第１照射工程で、図８に示したように、押さえ棒によって外装缶と負極リードを密着させることなく、外装缶と負極リードとの間に隙間が設けられた状態で、第１溶融部５６を形成する第１レーザ光４０を外装缶５０の外側から底板部５１に照射した。 [Example 2]
Example 2 corresponds to another manufacturing method of the embodiment shown in FIG. The configuration and dimensions of the battery of Example 2 are the same as those of Example 1. In the manufacturing method of Example 2, as in Example 1, general equipment lubricating oil was applied between the outer can 50 and the negative electrode lead 26. Thereafter, in Example 2, in the first irradiation step, as shown in FIG. 8, a gap is provided between the outer can and the negative electrode lead without causing the presser bar to closely contact the outer can and the negative electrode lead. Then, the first laser beam 40 that forms the first melting part 56 was applied to the bottom plate part 51 from the outside of the outer can 50.
　その後に、第２照射工程で、実施例１と同様に、押さえ棒７０(図７)によって外装缶５０と負極リード２６を密着させた状態で、第２溶融部５８を形成する第２レーザ光４１を照射することにより、外装缶５０と負極リード２６を溶接した。第１レーザ光４０及び第２レーザ光４１の照射条件は、実施例１と同様である。 Thereafter, in the second irradiation step, as in the first embodiment, the second laser beam that forms the second melting portion 58 in a state where the outer can 50 and the negative electrode lead 26 are brought into close contact with the pressing rod 70 (FIG. 7). The outer can 50 and the negative electrode lead 26 were welded by irradiating 41. The irradiation conditions of the first laser beam 40 and the second laser beam 41 are the same as those in the first embodiment.
　[比較例]
　また、比較例として、第１溶融部５６(図６、図８)を形成する第１レーザ光４０を照射せずに、第２レーザ光４１を照射して第２溶融部５８を形成することにより、外装缶と負極リードを溶接した電池を作製した。これにより、比較例の電池の製造方法では、外装缶の底部に第１溶融部が形成されず、負極リードと外装缶とを溶接する第２溶融部５８のみが形成された。その他の電池の構成及び寸法、第２レーザ光の照射条件は、実施例１と同様である。 [Comparative example]
Further, as a comparative example, the second melting portion 58 is formed by irradiating the second laser beam 41 without irradiating the first laser beam 40 forming the first melting portion 56 (FIGS. 6 and 8). Thus, a battery in which the outer can and the negative electrode lead were welded was produced. Thereby, in the battery manufacturing method of the comparative example, the first melting part was not formed at the bottom of the outer can, and only the second melting part 58 for welding the negative electrode lead and the outer can was formed. The other configurations and dimensions of the battery and the irradiation conditions of the second laser light are the same as those in the first embodiment.
［実験結果］
　表１は、上記の製造方法のそれぞれで作製された実施例１、２、比較例の電池を用いて、外装缶５０を貫通する穴の発生確率を確認した結果を示している。実験では、実施例１、２、比較例のそれぞれで複数の電池を作製し、穴の発生確率を確認した。 [Experimental result]
Table 1 shows the results of confirming the probability of occurrence of a hole penetrating the outer can 50 using the batteries of Examples 1 and 2 and Comparative Example produced by each of the above manufacturing methods. In the experiment, a plurality of batteries were produced in each of Examples 1 and 2 and Comparative Example, and the probability of occurrence of holes was confirmed.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示すように、比較例のように、第１溶融部を形成する第１レーザ光を照射せずに、第２レーザ光４１を照射して第２溶融部５８を形成した場合に、外装缶５０を貫通する穴の発生確率は１０％であった。 As shown in Table 1, when the second melted portion 58 is formed by irradiating the second laser beam 41 without irradiating the first laser beam forming the first melted portion as in the comparative example, The probability of occurrence of holes penetrating the outer can 50 was 10%.
　一方、実施例１のように、第１溶融部５６を形成する第１レーザ光４０を照射した後に、第２レーザ光４１を照射して第２溶融部５８を形成した場合に、外装缶５０を貫通する穴の発生確率は５％に減少することが確認できた。 On the other hand, when the second melted portion 58 is formed by irradiating the second laser beam 41 after irradiating the first laser beam 40 that forms the first melted portion 56 as in the first embodiment, the outer can 50 is formed. It has been confirmed that the probability of occurrence of a hole penetrating through is reduced to 5%.
　さらに、実施例２のように、外装缶５０と負極リード２６の間に隙間を設けて、互いに密着させない状態で第１溶融部５６を形成する第１レーザ光４０を照射した場合に、外装缶５０を貫通する穴の発生確率は０％に減少することが確認できた。これにより、実施例２の場合には、実施例１のように、第１レーザ光の照射時に、外装缶５０と負極リード２６の間に隙間を形成せず互いに密着させた状態とした場合に比べて、外装缶５０を貫通する穴の発生確率を減少できた。その理由は、実施例２では、第１レーザ光４０が照射されたことで発せられた熱が外装缶５０の中に留まり、負極リード２６や、外装缶５０と負極リード２６を密着させる押さえ棒に熱が吸収されることがないためである。このため、実施例２では、外装缶５０と負極リード２６の間に存在する樹脂を効率よく気化させることができた。 Further, as in the second embodiment, when a gap is provided between the outer can 50 and the negative electrode lead 26 and the first laser beam 40 that forms the first melting portion 56 is irradiated without being in close contact with each other, the outer can It was confirmed that the probability of occurrence of holes penetrating 50 decreased to 0%. As a result, in the case of the second embodiment, as in the first embodiment, when the first laser beam is irradiated, the gap between the outer can 50 and the negative electrode lead 26 is not formed, and the two are in close contact with each other. In comparison, the probability of occurrence of holes penetrating the outer can 50 could be reduced. The reason for this is that in Example 2, the heat generated by the irradiation of the first laser beam 40 stays in the outer can 50, and the negative electrode lead 26, or the presser bar that closely contacts the outer can 50 and the negative electrode lead 26. This is because heat is not absorbed by the heat sink. For this reason, in Example 2, the resin existing between the outer can 50 and the negative electrode lead 26 could be efficiently vaporized.
　図９は、実施形態の別例の電池２０ａの底面側半部の断面図である。図１０は、図９に示す電池２０ａの底面図である。 FIG. 9 is a cross-sectional view of the bottom half of a battery 20a according to another example of the embodiment. 10 is a bottom view of the battery 20a shown in FIG.
　図９、図１０に示す別例では、外装缶５０と負極リード２６とを溶接する３本の線状の平行な溶接部５４ａ、５４ｂ、５４ｃからなる溶接群６０が形成される。３本の溶接部５４ａ、５４ｂ、５４ｃからなる溶接群６０が形成されることで、外装缶５０と負極リード２６との溶接強度を確保しやすい。図９、図１０には、３本の平行な溶接部からなる溶接群６０を図示しているが、勿論、溶接部は３本に限定するものではなく、２本、または４本以上の複数本の溶接部が形成されてもよい。局所的にこのような溶接部を形成する際には、ファイバーレーザのレーザ光を用いることが好適である。本例において、その他の構成及び作用は、図１～図７の構成と同様である。 In another example shown in FIGS. 9 and 10, a weld group 60 including three linear parallel welds 54 a, 54 b and 54 c for welding the outer can 50 and the negative electrode lead 26 is formed. By forming the welded group 60 including the three welded portions 54a, 54b, and 54c, it is easy to ensure the welding strength between the outer can 50 and the negative electrode lead 26. 9 and 10 show a weld group 60 composed of three parallel welds. Of course, the number of welds is not limited to three, but two or more than four. A weld of a book may be formed. When forming such a weld locally, it is preferable to use a laser beam of a fiber laser. In this example, other configurations and operations are the same as those in FIGS. 1 to 7.
　上記の各例では、負極に接続された負極リードを外装缶に溶接する場合を説明したが、正極に接続された正極リードを外装缶に溶接する場合にも、本開示の構成を適用することができる。 In each of the above examples, the case where the negative electrode lead connected to the negative electrode is welded to the outer can has been described. Can do.
　上記の各例では、負極の巻き終わり側端部に接続された負極リードを外装缶に溶接する場合を説明したが、負極の巻き始め側端部に接続された負極リードを外装缶に溶接する場合にも本開示の構成を適用することができる。 In each of the above examples, the case where the negative electrode lead connected to the winding end side end portion of the negative electrode is welded to the outer can, but the negative electrode lead connected to the winding start side end portion of the negative electrode is welded to the outer can. Even in this case, the configuration of the present disclosure can be applied.
　上記の各例では、負極に接続された１本の負極リードを外装缶に溶接する場合を説明したが、負極に接続された複数本の負極リードを外装缶に溶接する場合にも、本開示の構成を適用することができる。 In each of the above examples, the case where one negative electrode lead connected to the negative electrode is welded to the outer can has been described, but the present disclosure is also applicable to the case where a plurality of negative electrode leads connected to the negative electrode are welded to the outer can. The configuration can be applied.
　２０，２０ａ　密閉電池（電池）、２２　電極体、２３　正極、２３ａ　正極集電体、２４　負極、２４ａ　負極集電体、２５　セパレータ、２６　負極リード、２９　巻き芯部、３０　絶縁板、４０　第１レーザ光、４１　第２レーザ光、５０　外装缶、５１　底板部、５４，５４ａ,５４ｂ,５４ｃ　溶接部、５６　第１溶融部、５８　第２溶融部、６０　溶接群、７０　押さえ棒。 20, 20a sealed battery (battery), 22 electrode body, 23 positive electrode, 23a positive electrode current collector, 24 negative electrode, 24a negative electrode current collector, 25 separator, 26 negative electrode lead, 29 winding core, 30 insulating plate, 40 1st Laser beam, 41, second laser beam, 50 outer can, 51 bottom plate, 54, 54a, 54b, 54c weld, 56 first melt, 58 second melt, 60 weld group, 70 presser bar.

Claims (5)

  1. 　少なくとも１つの正極と少なくとも１つの負極とがセパレータを介して巻回または積層された電極体と、前記電極体を収容する有底筒状の外装缶とを含む密閉電池の製造方法であって、
    　前記外装缶の外部からエネルギービームを照射して、前記正極及び前記負極の一方に接続されたリードを前記外装缶に溶接する溶接工程を備え、
    　前記溶接工程は、
    　前記外装缶の外側表面のうち、前記外装缶の内側表面を介して前記リードが対向する部分に、前記外装缶の内部に溶融痕である第１溶融部が留まるように制御された第１エネルギービームを照射する第１照射工程と、
    　前記第１照射工程後に、前記外装缶の外側表面のうち前記第１溶融部が露出している部分の内側に、前記外装缶の外側表面から前記リードの内部にかけて溶融痕である第２溶融部が形成されるように制御された第２エネルギービームを照射する第２照射工程と、を有する、
    　密閉電池の製造方法。     A method for producing a sealed battery, comprising: an electrode body in which at least one positive electrode and at least one negative electrode are wound or laminated via a separator; and a bottomed cylindrical outer can that accommodates the electrode body,
    Irradiating an energy beam from the outside of the outer can, and comprising a welding step of welding a lead connected to one of the positive electrode and the negative electrode to the outer can,
    The welding process includes
    The first energy controlled so that the first melting part which is a melting mark stays inside the outer can at the portion of the outer surface of the outer can facing the lead through the inner surface of the outer can. A first irradiation step of irradiating a beam;
    After the first irradiation step, a second melted portion that is a melt mark from the outer surface of the outer can to the inside of the lead inside the portion of the outer surface of the outer can where the first melted portion is exposed. A second irradiation step of irradiating a second energy beam controlled so as to be formed.
    A manufacturing method of a sealed battery.
  2. 　前記第１照射工程において、前記リードと前記外装缶の間に隙間が設けられた状態で前記第１エネルギービームを照射する、請求項１に記載の密閉電池の製造方法。 The method for manufacturing a sealed battery according to claim 1, wherein, in the first irradiation step, the first energy beam is irradiated in a state where a gap is provided between the lead and the outer can.
  3. 　前記第１エネルギービームのビームスポット径は、前記第２エネルギービームのビームスポット径より大きい、請求項１または請求項２に記載の密閉電池の製造方法。 The method for manufacturing a sealed battery according to claim 1 or 2, wherein a beam spot diameter of the first energy beam is larger than a beam spot diameter of the second energy beam.
  4. 　少なくとも１つの正極と少なくとも１つの負極とがセパレータを介して巻回または積層された電極体と、前記電極体を収容する有底筒状の外装缶とを備える密閉電池であって、
    　前記外装缶は、ニッケルめっきされた鉄により形成され、
    　前記正極及び前記負極の一方に接続されたリードと前記外装缶とが、前記外装缶の外側表面から前記リードに向けて形成された溶接部で溶接されており、
    　前記溶接部は、溶融痕である第１溶融部及び第２溶融部を含み、
    　前記第１溶融部が、前記外装缶の外側表面から前記外装缶の厚みの５０～９９％の範囲に形成され、
    　前記第２溶融部が、前記外装缶の外側表面から前記リードの内部にかけて形成され、前記外装缶の外側から前記溶接部を見た場合に、前記第１溶融部の内側にある、密閉電池。     A sealed battery comprising an electrode body in which at least one positive electrode and at least one negative electrode are wound or laminated with a separator interposed therebetween, and a bottomed cylindrical outer can that accommodates the electrode body,
    The outer can is formed of nickel-plated iron,
    The lead connected to one of the positive electrode and the negative electrode and the outer can are welded at a weld formed from the outer surface of the outer can toward the lead,
    The welded portion includes a first melting portion and a second melting portion that are melting marks,
    The first melting portion is formed in the range of 50 to 99% of the thickness of the outer can from the outer surface of the outer can;
    The sealed battery, wherein the second melting portion is formed from the outer surface of the outer can to the inside of the lead, and is located inside the first melting portion when the welded portion is viewed from the outer side of the outer can.
  5. 　前記第２溶融部のニッケル濃度（質量％）が前記第１溶融部より高い、請求項４に記載の密閉電池。 The sealed battery according to claim 4, wherein the nickel concentration (mass%) of the second melting part is higher than that of the first melting part.
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