WO2016103943A1 - Rectangular secondary battery - Google Patents

Rectangular secondary battery Download PDF

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Publication number
WO2016103943A1
WO2016103943A1 PCT/JP2015/081678 JP2015081678W WO2016103943A1 WO 2016103943 A1 WO2016103943 A1 WO 2016103943A1 JP 2015081678 W JP2015081678 W JP 2015081678W WO 2016103943 A1 WO2016103943 A1 WO 2016103943A1
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WO
WIPO (PCT)
Prior art keywords
battery
secondary battery
film
opening
adhesive
Prior art date
Application number
PCT/JP2015/081678
Other languages
French (fr)
Japanese (ja)
Inventor
伸行 堀
勇人 小口
博昭 江川
Original Assignee
日立オートモティブシステムズ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
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Application filed by 日立オートモティブシステムズ株式会社 filed Critical 日立オートモティブシステムズ株式会社
Publication of WO2016103943A1 publication Critical patent/WO2016103943A1/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
    • H01M50/572—Means for preventing undesired use or discharge
    • H01M50/584—Means for preventing undesired use or discharge for preventing incorrect connections inside or outside the batteries
    • H01M50/59—Means for preventing undesired use or discharge for preventing incorrect connections inside or outside the batteries characterised by the protection means
    • H01M50/591—Covers
    • 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 of a single cell or a single battery
    • H01M50/102—Primary casings, jackets or wrappings of a single cell or a single battery characterised by their shape or physical structure
    • H01M50/103—Primary casings, jackets or wrappings of a single cell or a single battery characterised by their shape or physical structure prismatic or rectangular
    • 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 of a single cell or a single battery
    • H01M50/147—Lids or covers
    • 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 of a single cell or a single battery
    • H01M50/172—Arrangements of electric connectors penetrating the casing
    • H01M50/174—Arrangements of electric connectors penetrating the casing adapted for the shape of the cells
    • H01M50/176—Arrangements of electric connectors penetrating the casing adapted for the shape of the cells for prismatic or rectangular cells
    • 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
    • H01M50/30—Arrangements for facilitating escape of gases
    • 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 invention relates to a rectangular secondary battery used for in-vehicle use.
  • secondary batteries with large capacity have been developed as power sources for hybrid electric vehicles, pure electric vehicles, etc.
  • prismatic lithium ion secondary batteries with high energy density (Wh / kg) are of particular interest.
  • Wh / kg prismatic lithium ion secondary batteries with high energy density
  • Patent Document 1 As a technique for coating a square secondary battery with an insulating material, a resin coating method for the square secondary battery is known (see Patent Document 1 below).
  • the positive electrode side of the secondary battery body is covered with an insulating lid member, a shrink film stretched into a tube shape is cut into a predetermined dimension, and the shrink film is applied to the shrink film. Insert the secondary battery body.
  • tip part of the secondary battery main body of a shrink film is closed in a bag shape, or it makes a belt
  • the opening end of the tubular shrink film is disposed outside the insulating lid member that covers the positive electrode side of the secondary battery body, and the prismatic secondary battery Exposed on the outer surface.
  • the shrink film expands and contracts with the expansion and contraction of the electrode due to charging / discharging of the square secondary battery, or the tube-shaped
  • the opening end of a shrink film may peel from an insulating cover member.
  • the opening end of the shrink film which covers the battery container of a square secondary battery peels, there exists a possibility that the insulation with respect to the external environment of a battery container may be impaired.
  • the present invention has been made in view of the above problems, and prevents the insulation material covering the battery case of the square secondary battery from being peeled off, thereby improving the insulation reliability of the battery case with respect to the external environment.
  • An object is to provide a secondary battery.
  • the prismatic secondary battery of the present invention is a prismatic secondary battery including a prismatic battery container, and has an opening at one end, and a part of the battery container is exposed from the opening.
  • the battery container is covered with the insulating stretch film, and the battery container exposed from the opening of the stretch film and the edge of the opening of the stretch film are covered with the insulating adhesive film.
  • FIG. 1 is an external perspective view showing a prismatic secondary battery according to Embodiment 1 of the present invention.
  • FIG. 1B is an enlarged sectional view taken along line BB shown in FIG. 1A.
  • the exploded perspective view of the square secondary battery shown in FIG. FIG. 4 is an exploded perspective view of the electrode group shown in FIG. 3.
  • Sectional drawing explaining the modification 1 of the insulation coating process of the square secondary battery shown to FIG. 1A The perspective view explaining the modification 2 of the insulation coating process of the square secondary battery shown to FIG. 1A.
  • the perspective view explaining the modification 2 of the insulation coating process of the square secondary battery shown to FIG. 1A The perspective view explaining the modification 2 of the insulation coating process of the square secondary battery shown to FIG. 1A.
  • the perspective view explaining the modification 2 of the insulation coating process of the square secondary battery shown to FIG. 1A The external appearance perspective view which shows the square secondary battery which concerns on Embodiment 2 of this invention.
  • the external appearance perspective view which shows the square secondary battery which concerns on Embodiment 3 of this invention.
  • the disassembled perspective view which removed the adhesive film from the square secondary battery shown to FIG. 9A.
  • the external appearance perspective view which shows the square secondary battery which concerns on Embodiment 4 of this invention.
  • FIG. 1A is an external perspective view of a prismatic secondary battery 100 according to Embodiment 1 of the present invention.
  • FIG. 1B is an enlarged sectional view taken along line BB of FIG. 1A.
  • the prismatic secondary battery 100 of the present embodiment is a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery, for example, and includes a prismatic battery container 10, an electrically insulating stretchable film 1 that covers the battery container 10, and An adhesive film 2 is provided.
  • the stretchable film 1 has an opening 1a at one end, and covers the battery container 10 with a part of the battery container 10 exposed from the opening 1a.
  • the adhesive film 2 covers the battery container 10 exposed from the opening 1a of the stretchable film 1, and covers the edge 1b of the opening 1a of the stretchable film 1. That is, in the rectangular secondary battery 100, the outer surface of the battery container 10 is insulated and coated with the stretchable film 1 and the adhesive film 2.
  • the stretchable film 1 is a sheet-like or film-like member made of a resin material having thermoplasticity, such as PP (polypropylene), PE (polyethylene), or nylon.
  • the stretchable film 1 may be made of a heat-shrinkable resin material such as PET (polyethylene terephthalate) or PP.
  • the stretchable film 1 may be colorless and transparent, or may be colored, and may be a single layer or multiple layers.
  • a resin sheet or a resin film in which PE and nylon are laminated can be used.
  • the adhesive film 2 includes a sheet-like or film-like base material layer 2 ⁇ and an adhesive layer 2 ⁇ for attaching the base material layer 2 ⁇ to the battery container 10 or the stretchable film 1.
  • the base material layer 2 ⁇ of the adhesive film 2 can be made of the same material as that of the stretchable film 1, for example.
  • the base material layer 2 ⁇ of the pressure-sensitive adhesive film 2 is made of a resin material having heat shrinkability such as PET or PP.
  • a general adhesive such as silicone or acrylic, which is used for an insulating tape for electrode insulation of a general secondary battery, is used. Can do.
  • the tensile strength of the adhesive film 2 is stronger than the tensile strength of the stretchable film 1.
  • Such a magnitude relationship between the tensile strengths can be realized, for example, by appropriately setting the thickness and material of the stretchable film 1 and the thickness and material of the adhesive film 2.
  • the adhesive force between the adhesive layer 2 ⁇ of the adhesive film 2 and the stretchable film 1 is stronger than the adhesive force between the stretchable film 1 and the battery container 10, and the adhesive layer 2 ⁇ of the adhesive film 2 It is weaker than the adhesive force between the substrate layer 2 ⁇ and the substrate layer 2 ⁇ . Furthermore, in this embodiment, the adhesive force between the adhesive layer 2 ⁇ and the base material layer 2 ⁇ of the adhesive film 2 is stronger than the adhesive force between the adhesive layer 2 ⁇ and the battery container 10. In other words, the holding force between the adhesive layer 2 ⁇ and the base material layer 2 ⁇ is larger than the holding force between the adhesive layer 2 ⁇ and the stretchable film 1.
  • the holding force between the adhesive layer 2 ⁇ and the base material layer 2 ⁇ is larger than the holding force between the stretchable film 1 and the battery container 10.
  • a magnitude relationship between the adhesive force and the holding force is, for example, the contact area between the adhesive layer 2 ⁇ and the base material layer 2 ⁇ of the adhesive film 2 between the adhesive layer 2 ⁇ and the stretchable film 1 or the battery container 10. This can be realized by making it larger than the contact area.
  • an easy adhesion process for roughening the surface of the base material layer 2 ⁇ of the adhesive film 2 is performed, or a smoothing process for reducing the surface roughness of the stretchable film 1 or the battery container 10 is performed.
  • the contact area of each member with respect to the adhesion layer 2 (beta) of the adhesion film 2 can be increased / decreased.
  • the smoothing process of the surface of the battery container 10 for example, the surface of the battery container 10 is subjected to a mold release process such as silicon coating, and the adhesive force between the battery container 10 and the adhesive layer 2 ⁇ of the adhesive film 2 is relatively set. Reduction.
  • FIG. 2 is an external perspective view showing a state before the battery container 10 of the rectangular secondary battery 100 shown in FIG. 1A is insulation-coated with the stretchable film 1 and the adhesive film 2.
  • FIG. 3 is an exploded perspective view of the prismatic secondary battery 100 before insulation coating shown in FIG.
  • the prismatic secondary battery 100 of the present embodiment is, for example, a prismatic lithium ion secondary battery including a rectangular box-shaped battery container 10.
  • the battery container 10 has a bottomed rectangular tube-shaped battery can 11 that is open at one end by an opening 11 a and accommodates the electrode group 40 therein, and a battery lid 12 that seals the opening 11 a of the battery can 11. ing.
  • the battery can 11 and the battery lid 12 are made of a metal material such as aluminum or an aluminum alloy, for example.
  • the battery can 11 has a flat rectangular shape corresponding to the flat electrode group 40 accommodated therein.
  • the battery can 11 has a substantially rectangular bottom surface 11b formed by a bottom wall that closes the bottom and faces the battery lid 12, a wide side surface 11c formed by a pair of side walls facing the thickness direction, and a width direction. And a narrow side surface 11d formed by a pair of opposing side walls.
  • the battery lid 12 is a substantially rectangular plate-like member that seals the rectangular opening 11a of the battery can 11, and is provided with positive and negative external terminals 20A and 20B at one end and the other end in the longitudinal direction.
  • the positive external terminal 20A is made of, for example, aluminum or an aluminum alloy
  • the negative external terminal 20B is made of, for example, copper or a copper alloy.
  • the positive electrode and the negative electrode external terminals 20A and 20B are collectively referred to as the external terminal 20.
  • the external terminal 20 has a weld joint 21 that is welded to a bus bar or the like.
  • the welded joint portion 21 is formed in a block shape having a substantially rectangular parallelepiped shape, with a lower end surface facing the upper surface of the battery lid 12 and an upper end surface parallel to the upper surface of the battery lid 12.
  • a columnar connection portion 21 a extending in a direction perpendicular to the upper surface of the battery lid 12 is provided on the lower end surface of the weld joint portion 21.
  • the gasket 3 is disposed between the external terminal 20 and the battery cover 12.
  • the gasket 3 is made of an insulating resin material such as polybutylene terephthalate, polyphenylene sulfide, perfluoroalkoxy fluorine resin, or the like.
  • the gasket 3 has a through-hole 3 a through which the connection portion 21 a of the external terminal 20 is inserted, and a side wall portion 3 b that covers a part of the side surface of the weld joint portion 21 of the external terminal 20.
  • the battery lid 12 has a pair of through holes 12a through which the connection portions 21a of the external terminals 20 are inserted at both ends in the longitudinal direction. Further, the battery cover 12 has a gas discharge valve 13 and a liquid injection port 14 in an intermediate portion between the pair of through holes 12a.
  • the gas discharge valve 13 is provided, for example, by thinning the battery lid 12 to form a groove 13a, and is cleaved to release the internal gas when the internal pressure of the battery container 10 exceeds a predetermined value. As a result, the pressure inside the battery container 10 is reduced.
  • the liquid injection port 14 is used to inject an electrolytic solution into the battery container 10, and is sealed by, for example, a liquid injection stopper 15 being welded by laser welding.
  • positive and negative current collector plates 30A and 30B are fixed via insulating plates 4 at positions corresponding to the positive and negative electrode external terminals 20A and 20B disposed on the outer surface.
  • the positive electrode current collector plate 30A is made of, for example, aluminum or an aluminum alloy
  • the negative electrode current collector plate 30B is made of, for example, copper or a copper alloy.
  • the insulating plate 4 is made of, for example, a resin material having insulation similar to that of the gasket 3.
  • the positive and negative current collector plates 30A and 30B are collectively referred to as the current collector plate 30.
  • the current collecting plate 30 is a rectangular plate-shaped base portion 31 that is disposed to face the lower surface of the battery lid 12, and is bent at a side end of the base portion 31 so as to extend toward the bottom surface 11 b along the wide side surface 11 c of the battery can 11. And a terminal portion 32 extending in the direction.
  • the insulating plate 4 is disposed between the inner surface of the battery lid 12, that is, the lower surface, and the base 31 of the current collector plate 30, so that the battery lid 12 and the current collector plate 30 are electrically insulated.
  • the base 31 and the insulating plate 4 of the current collector plate 30 have through holes 31a and 4a through which the connection portions 21a of the external terminals 20 are inserted, respectively.
  • External terminal 20, gasket 3, insulating plate 4, and current collector plate 30 are caulked and fixed to battery lid 12.
  • the connecting portion 21 a of the external terminal 20 is connected to the through hole 3 a of the gasket 3, the through hole 12 a of the battery lid 12, the through hole 4 a of the insulating plate 4, and the through hole 31 a of the base 31 of the current collector plate 30.
  • the tip of the connecting portion 21a is plastically deformed to expand the diameter, thereby forming a caulking portion.
  • the external terminal 20, the gasket 3, the insulating plate 4, and the current collector plate 30 are caulked and fixed to the battery lid 12, and the external terminal 20 and the current collector plate 30 are electrically connected.
  • the external terminals 20 and the current collector plate 30 are electrically insulated from the battery lid 12 by the gasket 3 and the insulating plate 4.
  • the electrode group 40 bundles the foil exposed portions 41c and 42c of the positive and negative electrodes 41 and 42 (see FIG. 3), and, for example, the terminals of the positive and negative current collector plates 30A and 30B by ultrasonic welding or resistance welding, respectively. It is joined to the part 32.
  • the electrode group 40 is electrically connected to the external terminal 20 via the current collector plate 30 and is fixed to the battery lid 12 via the current collector plate 30.
  • the electrode group 40 is covered with an insulating protective film 5 made of synthetic resin such as polypropylene and electrically insulated from the battery can 11, and is inserted into the battery can 11 from the opening 11 a of the battery can 11. Yes.
  • the battery lid 12 is welded over the entire circumference of the opening 11a of the battery can 11 by laser welding, and the opening 11a of the battery can 11 is sealed with the battery lid 12, so that the battery container 10 is It is formed.
  • the nonaqueous electrolytic solution is injected into the battery container 10 through the liquid injection port 14 of the battery lid 12 to accommodate the nonaqueous electrolytic solution in the battery can 11, and the injection plug 15 is injected by laser welding, for example.
  • the battery container 10 is hermetically sealed by bonding to the liquid port 14 and sealing.
  • a nonaqueous electrolytic solution to be injected into the battery container 10 for example, a nonaqueous electrolytic solution in which a lithium salt such as lithium hexafluorophosphate (LiPF 6 ) is dissolved in a carbonic acid ester-based organic solvent such as ethylene carbonate. Liquid can be applied.
  • FIG. 4 is an exploded perspective view in which a part of the electrode group 40 shown in FIG. 3 is developed.
  • the electrode group 40 is a wound electrode group in which a positive electrode and a negative electrode 41, 42 laminated with separators 43 and 44 interposed therebetween are wound around an axis parallel to the winding axis A and formed into a flat shape.
  • the separators 43 and 44 insulate the positive electrode 41 and the negative electrode 42, and the separator 44 is wound outside the negative electrode 42 wound around the outermost periphery.
  • the separators 43 and 44 are made of, for example, a porous polyethylene resin.
  • the electrode group 40 has a pair of flat portions 40a on both sides in the thickness direction in which the positive and negative electrodes 41 and 42 are flatly laminated, and the positive and negative electrodes 41 and 42 are curved and laminated on both sides of the flat portion 40a. It has a pair of semi-cylindrical curved portions 40b.
  • the electrode group 40 is inserted into the battery can 11 so that the winding axis A is parallel to the bottom surface 11 b and the wide side surface 11 c of the battery can 11, and the pair of flat portions 40 a are formed on the pair of wide side surfaces 11 c of the battery can 11.
  • a pair of curved portions 40 b are disposed to face each other and face the battery lid 12 and the bottom surface 11 b of the battery can 11.
  • the positive electrode 41 has a positive electrode foil 41a that is a positive electrode current collector, and a positive electrode mixture layer 41b made of a positive electrode active material mixture applied to both surfaces of the positive electrode foil 41a.
  • One side of the positive electrode 41 in the width direction is a foil exposed portion 41c where the positive electrode mixture layer 41b is not formed and the positive foil 41a is exposed.
  • the positive electrode 41 is wound around the winding axis A, with the foil exposed portion 41 c disposed on the opposite side of the foil exposed portion 42 c of the negative electrode 42 in the winding axis A direction.
  • the positive electrode 41 for example, a positive electrode active material mixture kneaded by adding a conductive material, a binder and a dispersion solvent to the positive electrode active material, is applied to both surfaces of the positive electrode foil 41a except for one side in the width direction, It can be produced by drying, pressing and cutting.
  • As the positive electrode foil 41a for example, an aluminum foil with a thickness of about 20 ⁇ m can be used.
  • the thickness of the positive electrode mixture layer 41b not including the thickness of the positive electrode foil 41a is, for example, about 90 ⁇ m.
  • the positive electrode active material mixture for example, 100 parts by weight of lithium manganate (chemical formula LiMn 2 O 4 ) is used as the positive electrode active material, 10 parts by weight of flaky graphite as the conductive material, and 10% by weight as the binder.
  • Part of polyvinylidene fluoride (hereinafter referred to as PVDF) and N-methylpyrrolidone (hereinafter referred to as NMP) can be used as a dispersion solvent.
  • the positive electrode active material is not limited to the above-described lithium manganate.
  • another lithium manganate having a spinel crystal structure, or a lithium manganese composite oxide partially substituted or doped with a metal element may be used.
  • lithium cobalt oxide or lithium titanate having a layered crystal structure, or a lithium-metal composite oxide in which a part thereof is substituted or doped with a metal element may be used.
  • the negative electrode 42 has a negative electrode foil 42a which is a negative electrode current collector, and a negative electrode mixture layer 42b made of a negative electrode active material mixture coated on both surfaces of the negative electrode foil 42a.
  • One side in the width direction of the negative electrode 42 is a foil exposed portion 42c where the negative electrode mixture layer 42b is not formed and the negative foil 42a is exposed.
  • the negative electrode 42 is wound around the winding axis A such that the foil exposed portion 42 c is disposed on the opposite side of the foil exposed portion 41 c of the positive electrode 41 in the winding axis A direction.
  • the negative electrode 42 is prepared by applying a negative electrode active material mixture kneaded by adding a binder and a dispersion solvent to the negative electrode active material on both sides of the negative electrode foil 42a except for one side in the width direction, drying, pressing, It can be produced by cutting.
  • a negative electrode foil 42a for example, a copper foil having a thickness of about 10 ⁇ m can be used.
  • the thickness of the negative electrode mixture layer 42b not including the thickness of the negative electrode foil 42a is, for example, about 70 ⁇ m.
  • the negative electrode active material mixture for example, 100 parts by weight of amorphous carbon powder as the negative electrode active material, 10 parts by weight of PVDF as the binder, and NMP as the dispersion solvent can be used.
  • the negative electrode active material is not limited to the above-mentioned amorphous carbon, and natural graphite capable of inserting and removing lithium ions, various artificial graphite materials, carbonaceous materials such as coke, and compounds such as Si and Sn (for example, , SiO, TiSi 2 or the like), or a composite material thereof.
  • the particle shape of the negative electrode active material is not particularly limited, and a particle shape such as a scale shape, a spherical shape, a fiber shape, or a lump shape can be appropriately selected.
  • the binder used for the above-described positive electrode and negative electrode mixture layers 41b and 42b is not limited to PVDF.
  • the binder include polytetrafluoroethylene (PTFE), polyethylene, polystyrene, polybutadiene, butyl rubber, nitrile rubber, styrene butadiene rubber, polysulfide rubber, nitrocellulose, cyanoethyl cellulose, various latexes, acrylonitrile, and vinyl fluoride.
  • Polymers such as vinylidene fluoride, propylene fluoride, chloroprene fluoride, and acrylic resins, and mixtures thereof may be used.
  • the axial core when winding the positive electrode 41 and the negative electrode 42 with the separators 43 and 44 interposed therebetween is, for example, more flexible than the positive foil 41a, the negative foil 42a, and the separators 43 and 44.
  • a roll of a high resin sheet can be used.
  • the width of the negative electrode mixture layer 42b of the negative electrode 42 is wider than the width of the positive electrode mixture layer 41b of the positive electrode 41.
  • a negative electrode 42 is wound around the innermost and outermost circumferences of the electrode group 40.
  • the positive electrode mixture layer 41b is sandwiched between the negative electrode mixture layer 42b from the innermost periphery to the outermost periphery of the electrode group 40.
  • the foil exposed portions 41c and 42c of the positive electrode 41 and the negative electrode 42 are respectively bundled by the flat portion 40a of the electrode group 40, and are joined to the terminal portion 32 of the current collector plate 30 by, for example, ultrasonic pressure welding or resistance welding. Accordingly, the positive and negative external terminals 20A and 20B are electrically connected to the positive and negative electrodes 41 and 42 constituting the electrode group 40 via the positive and negative current collector plates 30A and 30B, respectively.
  • the width of the separators 43 and 44 is wider than the width of the negative electrode mixture layer 42b, but the foil exposed portions 41c and 42c of the positive electrode 41 and the negative electrode 42 are respectively separators. It protrudes outward in the width direction from the ends in the width direction of 43 and 44. Therefore, the separators 43 and 44 do not hinder when the foil exposed portions 41c and 42c are bundled and welded.
  • the prismatic secondary battery 100 having such a configuration is used, for example, as an assembled battery in which a bus bar is welded to the upper surface of the welded joint portion 21 of the external terminal 20 and a plurality of prismatic secondary batteries 100 are connected in series.
  • the prismatic secondary battery 100 is charged by, for example, accumulating electric power supplied from a power supply source such as a generator in the electrode group 40 via the external terminal 20 and the current collector plate 30.
  • the prismatic secondary battery 100 supplies the power stored in the electrode group 40 to a device that consumes power, such as a motor, via the current collector plate 30 and the external terminal 20.
  • the prismatic secondary battery 100 opens the gas discharge valve 13 provided in the battery cover 12, and the inside of the battery case 10. This gas can be discharged to reduce the internal pressure. Thereby, the safety
  • FIG. 5A and 5B are perspective views for explaining an insulating coating process of the prismatic secondary battery 100 shown in FIG. 1A.
  • the prismatic secondary battery 100 before insulation coating and the stretchable film 1 for covering the battery container 10 of the prismatic secondary battery 100 are prepared.
  • the elastic film 1 is arrange
  • the stretchable film 1 of this embodiment is manufactured by the resin material which has the above-mentioned thermoplasticity. Therefore, for example, after the stretchable film 1 is heated and softened by a heater or the like, air is sucked from the battery lid 12 side of the battery container 10 by a suction device or the like, so that the battery container 10 is charged by the softened stretchable film 1.
  • the can 11 can be wrapped from the bottom surface 11b side.
  • the insulating stretchable film 1 has an opening 1a at one end and covers the battery container 10 with a part of the battery container 10 exposed from the opening 1a.
  • the stretchable film 1 and the battery container 10 can be brought into close contact with each other and the stretchable film 1 can be adhered to the battery container 10. it can.
  • the stretchable film 1 is in close contact with the bottom surface 11b of the battery can 11, the pair of wide side surfaces 11c, and the pair of narrow side surfaces 11d.
  • the stretchable film 1 exposes the upper end portion of the battery can 11 in the vicinity of the opening portion 11a and the entire battery lid 12 from the opening 1a, and excludes the battery lid 12 and the upper end portion of the battery can 11 from the battery. Most of the outer surface of the container 10 is covered. In other words, the stretchable film 1 exposes the battery lid 12, a part of the pair of wide side surfaces 11c of the battery can 11, and a part of the pair of narrow side surfaces 11d of the battery can 11 from the opening 1a. The other part of the container 10 is covered.
  • the stretchable film 1 may cover the entire battery can 11, that is, the welded portion between the battery can 11 and the battery lid 12 from the bottom surface 11 b of the battery can 11.
  • the welded portion between the battery can 11 and the battery lid 12 may have a larger surface roughness or unevenness than other portions of the battery container 10. Therefore, it is preferable that the welded part between the battery can 11 and the battery lid 12 is not covered with the stretchable film 1 from the viewpoint of improving the adhesion between the stretchable film 1 and the battery container 10 and preventing peeling.
  • the size of the stretchable film 1 may be set in advance so that the welded portion is exposed. You may make it expose a welding part according to a procedure. That is, first, the stretchable film 1 covers the bottom surface 11 b of the battery can 11 to the welded portion between the battery can 11 and the battery lid 12. Thereafter, the stretchable film 1 is cut along the battery lid 12 at a position closer to the bottom surface 11b of the battery can 11 than the welded portion between the battery can 11 and the battery lid 12, and the welded portion of the stretchable film 1 is covered. You may make it remove.
  • an adhesive film 2 that covers the battery container 10 exposed from the opening 1a of the stretchable film 1 is prepared. And the adhesive film 2 is arrange
  • FIG. As shown in FIGS. 1A and 1B, the adhesive film 2 covers the battery container 10 exposed from the opening 1 a of the stretchable film 1 and has an area and shape sufficient to cover the edge 1 b of the opening 1 a of the stretchable film 1. have.
  • the adhesive film 2 has a rectangular shape in which the width W direction of the battery container 10 is the longitudinal direction and the thickness T direction is the short direction.
  • the dimension D1 in the short direction of the adhesive film 2 is sufficiently larger than the sum of twice the height H of the battery container 10 exposed from the opening 1a of the stretchable film 1 and the thickness T.
  • the dimension D2 in the longitudinal direction of the adhesive film 2 is sufficiently larger than the sum of twice the height H of the exposed battery container 10 and the width W.
  • the dimension D1 in the short direction of the adhesive film 2 is larger than the sum of the height H and the thickness T of the exposed square secondary battery 100, and is approximately 6 times the height H. It is equal to the sum of the thickness T.
  • the dimension D2 in the longitudinal direction of the adhesive film 2 is larger than the sum of the height H and the width W of the exposed square secondary battery 100, and approximately 10 times the height H and a thickness. It is equal to the sum of T.
  • the adhesive film 2 has a through hole 2 a that exposes the external terminal 20 at a position corresponding to the external terminal 20. Moreover, in this embodiment, the adhesive film 2 has the through-hole 2b which exposes at least one part of the gas exhaust valve 13 in the position corresponding to the gas exhaust valve 13. As shown in FIG. In this embodiment, the through-hole 2b is formed in the center part of the gas exhaust valve 13 in the shape of a round long hole extending along the longitudinal direction, and a part of the gas exhaust valve 13, that is, the central part is exposed. The through hole 2b may be formed in a size that exposes the entire gas discharge valve 13.
  • the adhesive film 2 has an information display unit. You may have a through-hole to expose. In addition, when the adhesive film 2 is transparent or translucent, the adhesive film 2 does not need to have a through-hole which exposes an information display part.
  • the adhesive film 2 may be colored. In this case, for example, the color of the adhesive film 2 can be varied according to the specifications of the rectangular secondary battery 100 and the delivery destination. Further, the adhesive film 2 may be colored in different colors on the positive electrode external terminal 20A side and the negative electrode external terminal 20B side.
  • the adhesive film 2 can cover the battery container 10 exposed from the opening 1a of the stretchable film 1 and the edge 1b of the opening 1a of the stretchable film 1 by the following procedure. First, as shown in FIG. 5B, in a state where the adhesive film 2 is spread, the battery lid 12 is opposed to the through hole 2a and the through hole 2b, and the external terminal 20 and the gas discharge valve 13 are aligned. Next, the adhesive film 2 is affixed on the upper surface of the battery cover 12, and the external terminal 20 and the gas discharge valve 13 are exposed from the through hole 2a and the through hole 2b. Thereby, the battery cover 12 which is a part of the battery container 10 exposed from the opening 1 a of the stretchable film 1 is covered with the adhesive film 2.
  • both ends in the longitudinal direction of the adhesive film 2 protruding in the width W direction of the battery container 10 are folded at a crease 2 c and folded downward, that is, toward the bottom surface 11 b of the battery can 11.
  • the center part of the transversal direction of the adhesive film 2 turned back is affixed on a pair of narrow side surface 11d and the expansion-contraction film 1 of the battery can 11.
  • FIG. Thereby, the upper end part by the side of the battery lid 12 of a pair of narrow side surface 11d of the battery can 11 which is a part of the battery container 10 exposed from the opening 1a of the stretch film 1, and the stretch film on the pair of narrow side surface 11d
  • An edge 1 b of one opening 1 a is covered with an adhesive film 2.
  • both sides in the short direction of the adhesive film 2 that protrudes from the battery lid 12 in the thickness T direction of the battery container 10 are folded in a fold line 2d and folded downward, and the folded adhesive film 2
  • the intermediate part excluding both ends in the longitudinal direction is attached to the wide side surface 11 c of the battery can 11 and the stretchable film 1.
  • the adhesive film 2 is folded in a fold at the crease 2e, at the corner fold 2c between the wide side surface 11c and the narrow side surface 11d of the battery can 11, and then folded at the crease 2e.
  • the adhesive layers 2 ⁇ at the opposed portions are bonded together.
  • the upper end part of the battery lid 11 side of the pair of wide side surfaces 11c of the battery can 11 that is a part of the battery case 10 exposed from the opening 1a of the stretch film 1 and the stretch film 1 on the pair of wide side surfaces 11c.
  • the edge 1 b of the opening 1 a is covered with the adhesive film 2.
  • the adhesive film 2 that protrudes on both sides of the narrow side surface 11d of the battery can 11 has a triangular region in which the adhesive layer 2 ⁇ of the adhesive film 2 folded and overlapped at the fold 2e is bonded, and the lower side thereof Thus, a rectangular region where the adhesive layer 2 ⁇ is exposed is formed.
  • the adhesive film 2 that protrudes on both sides of the narrow side surface 11d is folded back toward the center in the width W direction of the battery container 10 at the fold 2d, and the rectangular region where the adhesive layer 2 ⁇ is exposed is removed from the battery can 11. It affixes on the elastic film 1 on the wide side surface 11c.
  • the prismatic secondary battery 100 shown in FIG. 1A can be obtained.
  • the adhesive film 2 may cut out beforehand the triangular area
  • the prismatic secondary battery 100 of the present embodiment has the opening 1a at one end, and the insulating stretchable film that covers the battery container 10 with a part of the battery container 10 exposed from the opening 1a. 1 and an insulating adhesive film 2 that covers the battery container 10 exposed from the opening 1a of the stretchable film 1 and covers the edge 1b of the opening 1a.
  • the edge 1b of the opening 1a of the stretchable film 1 is peeled off. Is prevented by the adhesive film 2 covering the surface. Therefore, according to the prismatic secondary battery 100 of the embodiment, the insulating stretchable film 1 and the adhesive film 2 that cover the battery container 10 of the prismatic secondary battery 100 are prevented from peeling off, and the battery container 10 is insulated from the external environment. Reliability can be improved.
  • the stretchable film 1 exposes the entire battery lid 12 from the opening 1a. This eliminates the need to cover the welded portion between the battery can 11 and the battery lid 12 with the stretchable film 1.
  • the welded portion may have a larger surface roughness or unevenness than other portions of the battery case 10. Therefore, it is possible to avoid covering the welded portion with the stretchable film 1, improve the adhesion between the stretchable film 1 and the battery container 10, and more effectively prevent the stretchable film 1 from peeling off.
  • the stretchable film 1 exposes the entire battery lid 12 from the opening 1a, so that the edge 1b of the opening 1a of the stretchable film 1 is disposed on the wide side surface 11c and the narrow side surface 11d of the battery can 11 to expand and contract.
  • the battery container 10 can be easily covered with the film 1.
  • the area which covers the edge 1b of the opening 1a of the stretchable film 1 by the adhesive film 2 can be made relatively large, and it becomes possible to more effectively prevent the stretchable film 1 from peeling off.
  • the adhesive film 2 has a through hole 2 a that covers the battery cover 12 exposed from the opening 1 a of the stretchable film 1 and exposes the external terminal 20.
  • the adhesive film 2 can insulate the battery cover 12 exposed from the opening 1a of the stretchable film 1 without hindering the joining of the bus bar to the weld joint 21 of the external terminal 20.
  • the stretchable film 1 includes a battery lid 12 side upper end portion that is a part of the pair of wide side surfaces 11c and a part of the narrow side surface 11d from the opening 1a. The upper end portion on the lid 12 side is exposed.
  • the adhesive film 2 covers a part of the wide side surface 11c and a part of the narrow side surface 11d exposed from the opening 1a of the stretchable film 1.
  • the adhesive film 2 covers the battery lid 12 and the four surfaces of the battery can 11 adjacent thereto. Thereby, the adhesive film 2 can be more firmly attached to the battery container 10 and the stretchable film 1 to prevent the adhesive film 2 from peeling off. As a result, the stretchable film 1 can be more effectively prevented from peeling off. Can do.
  • the adhesive film 2 has a through hole 2b that exposes at least a part of the gas discharge valve 13. Therefore, when the gas discharge valve 13 is opened when the internal pressure of the battery container 10 is increased, the gas discharge from the gas discharge valve 13 is prevented from being hindered by the adhesive film 2, and the safety of the rectangular secondary battery 100 is improved. Can be secured.
  • the stretchable film 1 is made of a resin material having thermoplasticity.
  • the stretchable film 1 is heated and softened, and the battery container 10 can be easily and reliably covered with the stretchable film 1 without any gaps by sucking under reduced pressure from one direction. Therefore, it is possible to improve the insulation reliability of the rectangular secondary battery 100, improve the productivity, and reduce the manufacturing cost.
  • the tensile strength of the adhesive film 2 is stronger than the tensile strength of the stretchable film 1. Therefore, even when a tensile stress acts between the adhesive film 2 and the edge 1b of the opening 1a of the stretchable film 1, the edge 1b of the opening 1a of the stretchable film 1 is firmly held by the adhesive film 2 and stretched. The peeling of the film 1 can be prevented more effectively.
  • the adhesive film 2 has the base material layer 2 ⁇ and the adhesive layer 2 ⁇ , and the adhesive force between the adhesive layer 2 ⁇ and the stretchable film 1 is the same as that of the stretchable film 1. It is stronger than the adhesive force between the battery container 10 and weaker than the adhesive force between the adhesive layer 2 ⁇ of the adhesive film 2 and the base material layer 2 ⁇ . In other words, the holding force between the adhesive layer 2 ⁇ and the base material layer 2 ⁇ is larger than the holding force between the adhesive layer 2 ⁇ and the stretchable film 1. Further, the holding force between the adhesive layer 2 ⁇ and the base material layer 2 ⁇ is larger than the holding force between the stretchable film 1 and the battery container 10. Thereby, the adhesive film 2 firmly holds the stretchable film 1 by the adhesive layer 2 ⁇ held by the base material layer 2 ⁇ , and is more firmly fixed to the battery container 10 than the stretchable film 1, so that the stretchable film 1 Peeling can be prevented more effectively.
  • the adhesive force between the adhesive layer 2 ⁇ and the base material layer 2 ⁇ of the adhesive film 2 is stronger than the adhesive force between the adhesive layer 2 ⁇ and the battery container 10.
  • the adhesive film 2 can be reattached, the yield of the adhesive film 2 in the manufacturing process of the square secondary battery 100 can be improved, and the manufacturing cost can be reduced.
  • the adhesive film 2 can be easily collected when the rectangular secondary battery 100 is recycled.
  • the adhesive film 2 when the adhesive film 2 is colored, when measuring the external dimensions of the square secondary battery 100 with a non-contact type measuring instrument such as a laser displacement meter.
  • the surface position of the adhesive film 2 can be accurately measured. Therefore, the measurement accuracy of the external dimensions of the prismatic secondary battery 100 can be improved.
  • by coloring in different colors depending on the specifications of the prismatic secondary battery 100 and the delivery destination it is possible to easily identify the specifications of the prismatic secondary battery 100 and the delivery destination. Further, if the adhesive film 2 is colored in different colors on the positive electrode external terminal 20A side and the negative electrode external terminal 20B side, the positive electrode and the negative electrode of the prismatic secondary battery 100 can be easily distinguished.
  • the stretchable film 1 and the adhesive film 2 that are insulating materials covering the battery container 10 are prevented from being peeled, and the battery container 10 is insulated from the external environment. Reliability can be improved.
  • the stretch film 1 made of a thermoplastic resin material is disposed on the bottom surface 11b side of the battery can 11, and the stretch film 1 softened by heating is used.
  • An example in which vacuum suction is performed from the battery lid 12 side has been described.
  • the insulating coating process of the prismatic secondary battery 100 is not limited to the above example.
  • modifications 1 and 2 of the insulating coating process of the prismatic secondary battery 100 will be described.
  • 6A and 6B are perspective views for explaining a first modification of the insulating coating process of the prismatic secondary battery 100 shown in FIG. 1A.
  • 6C is an enlarged cross-sectional view taken along the line CC of FIG. 6B. In FIG. 6C, the illustration of the configuration inside the battery can 11 is omitted.
  • a rectangular secondary battery 100 before insulation coating and a stretchable film 1 for covering the battery container 10 of the rectangular secondary battery 100 are prepared.
  • the elastic film 1 is arrange
  • the stretchable film 1 is made of a resin material having thermoplasticity as in the above-described embodiment. Therefore, for example, the elastic film 1 is heated and softened with a heater or the like, and then the softened elastic film 1 is brought into close contact with the battery container 10 by sucking air from the bottom surface 11b side of the battery can 11 with a suction device or the like. Can be wrapped from the battery lid 12 side.
  • the end of the stretchable film 1 on the bottom surface 11b side of the battery can 11 is welded together by overlapping on the bottom surface 11b of the battery can 11 as shown in FIG. A weld 1c is formed and sealed. Thereafter, for example, by cutting the stretchable film 1 at the upper end of the battery can 11 so that the welded portion between the battery lid 12 and the battery can 11 is exposed from the stretchable film 1, the battery lid 12 side of the battery container 10.
  • the opening 1a of the stretchable film 1 is formed on the surface.
  • the battery lid 12 exposed from the opening 1a is covered with the adhesive film 2 in the same manner as in the above-described embodiment.
  • the battery container 10 can be covered with the stretchable film 1 from the battery lid 12 side.
  • (Insulation coating process for prismatic secondary battery: Modification 2) 7A to 7E are perspective views for explaining a second modification of the insulating coating process of the prismatic secondary battery 100 shown in FIG. 1A.
  • the rectangular secondary battery 100 before the insulating coating and the battery container 10 of the rectangular secondary battery 100 are covered.
  • a stretchable film 1 is prepared.
  • the stretchable film 1 used in the present modification is made of a heat-shrinkable resin material such as the aforementioned PET or PP.
  • the stretchable film 1 is folded in half with the battery container 10 sandwiched by lifting both ends of the battery container 10 in the thickness direction toward the battery lid 12 side.
  • the stretchable film 1 is formed in a bag shape in which both end portions in the width direction of the battery container 10 are heat-welded along the narrow side surface 11d of the battery can 11 to form a heat-welded portion 1d, and an opening is formed on the battery lid 12 side. become.
  • the opening of the stretchable film 1 formed in a bag shape is thermally welded to form a heat welded portion 1d, and the entire battery container 10 including the external terminals 20 is stretched by the stretchable film 1. cover.
  • the stretchable film 1 covering the entire battery container 10 is heated and shrunk, and the stretchable film 1 is brought into close contact with the battery container 10.
  • the stretchable film 1 is cut at a position closer to the bottom surface 11b side of the battery can 11 than the welded portion between the battery lid 12 and the battery can 11 to form the opening 1a.
  • the battery lid 12 exposed from the opening 1a is covered with the adhesive film 2 in the same manner as in the above-described embodiment.
  • the battery container 10 can be covered with the stretchable film 1 regardless of vacuum suction.
  • the position of the heat welding part 1d of the elastic film 1 is not specifically limited. Moreover, what is necessary is just to form the opening 1a of the elastic film 1 so that the upper surface of the welding junction part 21 of the external terminal 20 may be exposed at least.
  • FIG. 8A is an external perspective view showing a prismatic secondary battery 100A according to Embodiment 2 of the present invention.
  • FIG. 8B is an exploded perspective view showing a state where the adhesive film 2 is removed from the rectangular secondary battery 100A shown in FIG. 8A.
  • the size of the opening 1a of the stretchable film 1A that covers the battery container 10 and the size of the adhesive film 2A that covers the battery container 10 are the square shapes described in the first embodiment. Different from the secondary battery 100.
  • the other points of the prismatic secondary battery 100A of the present embodiment are the same as those of the prismatic secondary battery 100 of Embodiment 1, and therefore, the same portions are denoted by the same reference numerals and description thereof is omitted.
  • the insulating coating process for closely attaching the stretchable film 1A of the present embodiment to the battery container 10 for example, the insulating coating process of the first embodiment described above and any one of the modifications 1 and 2 can be employed.
  • the size of the opening 1 a of the stretchable film 1 ⁇ / b> A in the width W direction of the battery container 10 is smaller than the size in the longitudinal direction of the battery lid 12, that is, the width W of the battery container 10. ing. Further, the size of the opening 1 a of the stretchable film 1 ⁇ / b> A along the wide side surface 11 c of the battery lid 12 and the battery can 11 is larger than the thickness T of the battery container 10. Thereby, the stretchable film 1A has five surfaces of the battery container 10, that is, the bottom surface 11b of the battery can 11, the pair of wide side surfaces 11c, the narrow side surface 11d, and both ends of the battery container 10 in the width W direction. The battery cover 12 is covered.
  • the stretchable film 1A the upper end portions of the battery lid 12 and the wide side surface 11c of the battery can 11 are exposed from the opening 1a in the middle portion excluding both end portions in the width W direction of the battery case 10.
  • the stretchable film 1A has three surfaces of the battery container 10, that is, the bottom surface 11b of the battery can 11 and the upper ends of the pair of wide side surfaces 11c at the intermediate portion excluding both ends in the width W direction of the battery container 10. It covers the part to be removed.
  • the stretchable film 1A exposes a part of the battery lid 12 and a part of the pair of wide side surfaces 11c of the battery can 11 from the opening 1a, and exposes both ends in the longitudinal direction of the battery lid 12 and the narrow side surface 11d. Covering without.
  • the adhesive film 2A has a dimension D2 in the longitudinal direction smaller than the width W of the battery container 10. Therefore, the adhesive film 2A has an intermediate portion in the longitudinal direction of the battery lid 12 exposed from the opening 1a of the stretchable film 1A, an upper end portion of the wide side surface 11c of the battery can 11, and an edge 1b of the opening 1a of the stretchable film 1A. Although covered, the pair of narrow side surfaces 11d are not covered. In other words, the adhesive film 2 ⁇ / b> A covers three surfaces of the battery container 10, that is, the pair of wide side surfaces 11 c of the battery lid 12 and the battery can 11.
  • the prismatic secondary battery 100A of the present embodiment not only the same effects as those of the prismatic secondary battery 100 of Embodiment 1 are obtained, but also compared with the prismatic secondary battery 100 of Embodiment 1 shown in FIG. 5B.
  • the step of folding the adhesive film 2A at the folds 2e and 2c and stacking them can be omitted. Therefore, the manufacturing of the rectangular secondary battery 100A can be facilitated and the productivity can be improved.
  • the adhesive film 2A does not fold over the wide side surface 11c of the battery can 11, as compared with the prismatic secondary battery 100 of the first embodiment, a set in which the prismatic secondary batteries 100A are arranged in the thickness T direction. The volume of the battery can be further reduced.
  • FIG. 9A is an external perspective view showing a prismatic secondary battery 100B according to Embodiment 3 of the present invention.
  • FIG. 9B is an exploded perspective view in which the adhesive film 2B is removed from the rectangular secondary battery 100B shown in FIG. 9A.
  • the size of the opening 1a of the stretchable film 1B covering the battery container 10 and the size of the adhesive film 2B covering the battery container 10 are described in the above-described first and second embodiments. This is different from the rectangular secondary batteries 100 and 100A.
  • the other points of the prismatic secondary battery 100B of the present embodiment are the same as those of the prismatic secondary battery 100 of Embodiment 1, and therefore the same parts are denoted by the same reference numerals and description thereof is omitted.
  • the insulating coating process for closely attaching the stretchable film 1B of the present embodiment to the battery container 10 for example, the insulating coating process of the first embodiment described above and any one of the modifications 1 and 2 can be employed.
  • the size of the opening 1 a of the stretchable film 1 ⁇ / b> B in the width W direction of the battery container 10 is smaller than the size in the longitudinal direction of the battery lid 12, that is, the width W of the battery container 10. ing. Further, the dimension of the opening 1 a of the stretchable film 1 ⁇ / b> B in the thickness T direction of the battery container 10 is smaller than the thickness T of the battery container 10. Thereby, the stretchable film 1 ⁇ / b> B covers the entire battery can 11 and exposes a part of the battery lid 12, that is, a portion excluding the peripheral edge of the battery lid 12 from the opening 1 a.
  • the adhesive film 2B covers the portion excluding the peripheral portion of the battery lid 12 exposed from the opening 1a of the stretchable film 1B and the edge 1b of the opening 1a of the stretchable film 1B.
  • the adhesive film 2 ⁇ / b> B covers only one surface of the battery container 10, i.e., the upper surface of the battery lid 12.
  • the prismatic secondary battery 100B of the present embodiment not only can the same effect as that of the prismatic secondary battery 100 of the first embodiment be obtained, but the stretchable film 1B and the adhesive film 2B are formed on the wide side surface 11c of the battery can 11. Since they do not overlap, the volume of the assembled battery in which the prismatic secondary batteries 100B are arranged in the thickness T direction can be further reduced as compared with the prismatic secondary battery 100A of the second embodiment.
  • FIG. 10 is an external perspective view showing a prismatic secondary battery 100C according to Embodiment 4 of the present invention.
  • the size of the through hole 2a that exposes the external terminal 20 of the adhesive film 2C that covers the battery container 10 is the same as that of the rectangular secondary battery 100 described in the first embodiment. It is smaller than the two through holes 2a.
  • the other points of the rectangular secondary battery 100C of the present embodiment are the same as those of the rectangular secondary battery 100 of the first embodiment, and therefore the same portions are denoted by the same reference numerals and description thereof is omitted.
  • the through-hole 2a of the adhesive film 2C exposes the weld joint 21 of the external terminal 20 and is equal to or larger than the outer dimension of the gasket 3 between the weld joint 21 and the battery lid 12. Is slightly smaller.
  • the adhesive layer 2 ⁇ is in close contact with the gasket 3 and covers at least a part of the gasket 3.
  • the adhesive film 2 ⁇ / b> C covers the lower end portion of the gasket 3, but may cover the entire gasket 3.
  • the adhesive film 2C is manufactured using the above-described resin material having heat shrinkability. And the adhesive film 2C is formed in a state where the through-hole 2a slightly larger than the outer dimensions of the weld joint 21 and the gasket 3 is formed in the adhesive film 2C, and the weld joint 21 and the gasket 3 are exposed from the through-hole 2a. Heat to shrink. Thereby, the through-hole 2a shrink
  • the adhesive film 2C when the adhesive film 2C is not thermally contracted, the adhesive film 2C may be adhered to the gasket 3 by using the stretchability of the adhesive film 2C.
  • the adhesive film 2C is formed to be slightly smaller than the outer dimension of the gasket 3, and the gasket 3 is pushed into the through-hole 2a to expand the through-hole 2a.
  • the gasket 3 may be covered by being in close contact therewith.
  • the adhesive film 2C is in close contact with the gasket 3 to cover the gasket 3, so that the battery lid 12 is not exposed from the through hole 2a of the adhesive film 2C.
  • the insulation property of the battery container 10 in the vicinity of 20 is improved.

Abstract

Provided is a rectangular secondary battery which is prevented from separation of an insulating material that covers a battery container of the rectangular secondary battery, so that reliability of insulation of the battery container from the outside environment is able to be improved. A rectangular secondary battery 100 which is provided with a rectangular battery container 10. This rectangular secondary battery 100 is also provided with: an insulating stretchable film 1 that has an opening 1a at one end and covers the battery container 10 in such a manner that a part of the battery container 10 is exposed from the opening 1a; and an insulating adhesive film 2 that covers the battery container 10 exposed from the opening 1a of the stretchable film 1, while covering an edge portion 1b of the opening 1a. The battery container 10 comprises: a battery can 11 which houses an electrode group 40 and is opened at one end; and a battery cover 12 which is provided with positive electrode and negative electrode external terminals 20, and which seals the battery can 11. At least a part of the battery cover 12 is exposed from the opening 1a of the stretchable film 1. The adhesive film 2 covers the battery cover 12 exposed from the opening 1a, while having through holes 2a from which the external terminals 20 are exposed.

Description

角形二次電池Prismatic secondary battery
　本発明は、車載用途等に使用される角形二次電池に関する。 The present invention relates to a rectangular secondary battery used for in-vehicle use.
　例えば、ハイブリッド電気自動車や純粋な電気自動車等の動力源として大容量（Ｗｈ）の二次電池が開発されており、その中でもエネルギー密度（Ｗｈ／ｋｇ）の高い角形のリチウムイオン二次電池が注目されている。このような角形二次電池においては、安全性を向上させる観点から、電池容器に設けられた安全弁からのガス排出を阻害することなく、電池容器の外表面を外部環境に対して電気的に絶縁することが要求される。 For example, secondary batteries with large capacity (Wh) have been developed as power sources for hybrid electric vehicles, pure electric vehicles, etc. Among them, prismatic lithium ion secondary batteries with high energy density (Wh / kg) are of particular interest. Has been. In such a rectangular secondary battery, from the viewpoint of improving safety, the outer surface of the battery container is electrically insulated from the external environment without obstructing gas discharge from the safety valve provided in the battery container. It is required to do.
　絶縁性を有する材料で角形二次電池を被覆する技術として、角形二次電池の樹脂被覆方法が知られている（下記特許文献１を参照）。特許文献１に記載された角形二次電池の樹脂被覆方法では、二次電池本体の正極側を絶縁性蓋部材で覆い、チューブ状に延伸したシュリンクフィルムを所定寸法に切断し、このシュリンクフィルムに二次電池本体を挿入する。そして、シュリンクフィルムの二次電池本体の負極側先端部を袋状に閉じ、又は帯状にして、シュリンクフィルムによって絶縁性蓋部材を含めて二次電池本体の外周面を熱収縮して被覆する。 As a technique for coating a square secondary battery with an insulating material, a resin coating method for the square secondary battery is known (see Patent Document 1 below). In the resin coating method for a square secondary battery described in Patent Document 1, the positive electrode side of the secondary battery body is covered with an insulating lid member, a shrink film stretched into a tube shape is cut into a predetermined dimension, and the shrink film is applied to the shrink film. Insert the secondary battery body. And the negative electrode side front-end | tip part of the secondary battery main body of a shrink film is closed in a bag shape, or it makes a belt | band | zone, and heat shrinks and coat | covers the outer peripheral surface of a secondary battery main body including an insulating cover member with a shrink film.
特開２００３－２２３８７２号公報JP 2003-238772 A
　特許文献１の樹脂被覆方法を用いた角形二次電池では、チューブ状のシュリンクフィルムの開口端が、二次電池本体の正極側を覆う絶縁性蓋部材の外側に配置され、角形二次電池の外表面に露出している。この場合、例えば、角形二次電池の充放電による電極の膨張収縮に伴ってシュリンクフィルムが伸縮し、又は、角形二次電池の発熱や環境温度の変化による熱的な負荷を受け、チューブ状のシュリンクフィルムの開口端が絶縁性蓋部材から剥がれる虞がある。このように、角形二次電池の電池容器を覆うシュリンクフィルムの開口端が剥がれると、電池容器の外部環境に対する絶縁性が損なわれる虞がある。 In the prismatic secondary battery using the resin coating method of Patent Document 1, the opening end of the tubular shrink film is disposed outside the insulating lid member that covers the positive electrode side of the secondary battery body, and the prismatic secondary battery Exposed on the outer surface. In this case, for example, the shrink film expands and contracts with the expansion and contraction of the electrode due to charging / discharging of the square secondary battery, or the tube-shaped There exists a possibility that the opening end of a shrink film may peel from an insulating cover member. Thus, when the opening end of the shrink film which covers the battery container of a square secondary battery peels, there exists a possibility that the insulation with respect to the external environment of a battery container may be impaired.
　本発明は、前記課題に鑑みてなされたものであり、角形二次電池の電池容器を覆う絶縁材料の剥がれを防止し、電池容器の外部環境に対する絶縁の信頼性を向上させることができる角形二次電池を提供することを目的とする。 The present invention has been made in view of the above problems, and prevents the insulation material covering the battery case of the square secondary battery from being peeled off, thereby improving the insulation reliability of the battery case with respect to the external environment. An object is to provide a secondary battery.
　前記目的を達成すべく、本発明の角形二次電池は、角形の電池容器を備えた角形二次電池であって、一端に開口を有し該開口から前記電池容器の一部を露出させた状態で前記電池容器を覆う絶縁性の伸縮フィルムと、該伸縮フィルムの前記開口から露出した前記電池容器を覆うとともに該開口の縁部を覆う絶縁性の粘着フィルムと、を備えることを特徴とする。 In order to achieve the above object, the prismatic secondary battery of the present invention is a prismatic secondary battery including a prismatic battery container, and has an opening at one end, and a part of the battery container is exposed from the opening. An insulating stretch film covering the battery container in a state, and an insulating adhesive film covering the battery container exposed from the opening of the stretch film and covering an edge of the opening. .
　本発明の角形二次電池によれば、絶縁性を有する伸縮フィルムによって電池容器を覆い、絶縁性を有する粘着フィルムによって伸縮フィルムの開口から露出した電池容器と伸縮フィルムの開口の縁部を覆うことで、角形二次電池の電池容器を覆う伸縮フィルムの剥がれを防止し、電池容器の外部環境に対する絶縁の信頼性を向上させることができる。 According to the prismatic secondary battery of the present invention, the battery container is covered with the insulating stretch film, and the battery container exposed from the opening of the stretch film and the edge of the opening of the stretch film are covered with the insulating adhesive film. Thus, it is possible to prevent the stretchable film covering the battery case of the square secondary battery from being peeled off, and to improve the insulation reliability with respect to the external environment of the battery case.
本発明の実施形態１に係る角形二次電池を示す外観斜視図。1 is an external perspective view showing a prismatic secondary battery according to Embodiment 1 of the present invention. 図１Ａに示すＢ－Ｂ線に沿う拡大断面図。FIG. 1B is an enlarged sectional view taken along line BB shown in FIG. 1A. 図１Ａに示す角形二次電池の絶縁被覆前の外観斜視図。The external appearance perspective view before the insulation coating of the square secondary battery shown to FIG. 1A. 図２に示す角形二次電池の分解斜視図。The exploded perspective view of the square secondary battery shown in FIG. 図３に示す電極群の分解斜視図。FIG. 4 is an exploded perspective view of the electrode group shown in FIG. 3. 図１Ａに示す角形二次電池の絶縁被覆工程を説明する斜視図。The perspective view explaining the insulation coating process of the square secondary battery shown to FIG. 1A. 図１Ａに示す角形二次電池の絶縁被覆工程を説明する斜視図。The perspective view explaining the insulation coating process of the square secondary battery shown to FIG. 1A. 図１Ａに示す角形二次電池の絶縁被覆工程の変形例１を説明する斜視図。The perspective view explaining the modification 1 of the insulation coating process of the square secondary battery shown to FIG. 1A. 図１Ａに示す角形二次電池の絶縁被覆工程の変形例１を説明する斜視図。The perspective view explaining the modification 1 of the insulation coating process of the square secondary battery shown to FIG. 1A. 図１Ａに示す角形二次電池の絶縁被覆工程の変形例１を説明する断面図。Sectional drawing explaining the modification 1 of the insulation coating process of the square secondary battery shown to FIG. 1A. 図１Ａに示す角形二次電池の絶縁被覆工程の変形例２を説明する斜視図。The perspective view explaining the modification 2 of the insulation coating process of the square secondary battery shown to FIG. 1A. 図１Ａに示す角形二次電池の絶縁被覆工程の変形例２を説明する斜視図。The perspective view explaining the modification 2 of the insulation coating process of the square secondary battery shown to FIG. 1A. 図１Ａに示す角形二次電池の絶縁被覆工程の変形例２を説明する斜視図。The perspective view explaining the modification 2 of the insulation coating process of the square secondary battery shown to FIG. 1A. 図１Ａに示す角形二次電池の絶縁被覆工程の変形例２を説明する斜視図。The perspective view explaining the modification 2 of the insulation coating process of the square secondary battery shown to FIG. 1A. 図１Ａに示す角形二次電池の絶縁被覆工程の変形例２を説明する斜視図。The perspective view explaining the modification 2 of the insulation coating process of the square secondary battery shown to FIG. 1A. 本発明の実施形態２に係る角形二次電池を示す外観斜視図。The external appearance perspective view which shows the square secondary battery which concerns on Embodiment 2 of this invention. 図８Ａに示す角形二次電池から粘着フィルムを取り外した分解斜視図。The disassembled perspective view which removed the adhesive film from the square secondary battery shown to FIG. 8A. 本発明の実施形態３に係る角形二次電池を示す外観斜視図。The external appearance perspective view which shows the square secondary battery which concerns on Embodiment 3 of this invention. 図９Ａに示す角形二次電池から粘着フィルムを取り外した分解斜視図。The disassembled perspective view which removed the adhesive film from the square secondary battery shown to FIG. 9A. 本発明の実施形態４に係る角形二次電池を示す外観斜視図。The external appearance perspective view which shows the square secondary battery which concerns on Embodiment 4 of this invention.
　以下、図面を参照して本発明の角形二次電池の実施の形態について詳細に説明する。 Hereinafter, embodiments of the prismatic secondary battery of the present invention will be described in detail with reference to the drawings.
（実施形態１）
　図１Ａは、本発明の実施形態１に係る角形二次電池１００の外観斜視図である。図１Ｂは、図１ＡのＢ－Ｂ線に沿う拡大断面図である。 (Embodiment 1)
FIG. 1A is an external perspective view of a prismatic secondary battery 100 according to Embodiment 1 of the present invention. FIG. 1B is an enlarged sectional view taken along line BB of FIG. 1A.
　本実施形態の角形二次電池１００は、例えば、リチウムイオン二次電池等の非水電解質二次電池であり、角形の電池容器１０と、該電池容器１０を覆う電気絶縁性の伸縮フィルム１及び粘着フィルム２を備えている。伸縮フィルム１は、一端に開口１ａを有し、該開口１ａから電池容器１０の一部を露出させた状態で電池容器１０を覆っている。粘着フィルム２は、伸縮フィルム１の開口１ａから露出した電池容器１０を覆うとともに、伸縮フィルム１の開口１ａの縁部１ｂを覆っている。すなわち、角形二次電池１００は、電池容器１０の外表面が、伸縮フィルム１及び粘着フィルム２によって絶縁被覆されている。 The prismatic secondary battery 100 of the present embodiment is a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery, for example, and includes a prismatic battery container 10, an electrically insulating stretchable film 1 that covers the battery container 10, and An adhesive film 2 is provided. The stretchable film 1 has an opening 1a at one end, and covers the battery container 10 with a part of the battery container 10 exposed from the opening 1a. The adhesive film 2 covers the battery container 10 exposed from the opening 1a of the stretchable film 1, and covers the edge 1b of the opening 1a of the stretchable film 1. That is, in the rectangular secondary battery 100, the outer surface of the battery container 10 is insulated and coated with the stretchable film 1 and the adhesive film 2.
　本実施形態において、伸縮フィルム１は、例えば、ＰＰ（ポリプロピレン）、ＰＥ（ポリエチレン）、ナイロン等、熱可塑性を有する樹脂材料によって製作されたシート状又はフィルム状の部材である。なお、伸縮フィルム１は、熱収縮性を有する樹脂材料、例えば、ＰＥＴ（ポリエチレンテレフタレート）、ＰＰ等によって製作してもよい。伸縮フィルム１は、無色透明でも着色されていてもよく、単層でも複層でもよい。伸縮フィルム１として、複層の樹脂材料を用いる場合には、例えば、ＰＥとナイロンを積層させた樹脂シート又は樹脂フィルムを用いることができる。 In this embodiment, the stretchable film 1 is a sheet-like or film-like member made of a resin material having thermoplasticity, such as PP (polypropylene), PE (polyethylene), or nylon. The stretchable film 1 may be made of a heat-shrinkable resin material such as PET (polyethylene terephthalate) or PP. The stretchable film 1 may be colorless and transparent, or may be colored, and may be a single layer or multiple layers. When a multilayer resin material is used as the stretchable film 1, for example, a resin sheet or a resin film in which PE and nylon are laminated can be used.
　粘着フィルム２は、シート状又はフィルム状の基材層２αと、該基材層２αを電池容器１０や伸縮フィルム１に貼り付けるための粘着層２βとを備えている。粘着フィルム２の基材層２αは、例えば、伸縮フィルム１と同様の材料で製作することができる。本実施形態において、粘着フィルム２の基材層２αは、例えば、ＰＥＴ又はＰＰ等、熱収縮性を有する樹脂材料によって製作されている。粘着フィルム２の粘着層２βの材料としては、例えば、一般的な二次電池の電極絶縁用途の絶縁テープに用いられているような、シリコーン系、アクリル系等の一般的な粘着剤を用いることができる。 The adhesive film 2 includes a sheet-like or film-like base material layer 2α and an adhesive layer 2β for attaching the base material layer 2α to the battery container 10 or the stretchable film 1. The base material layer 2α of the adhesive film 2 can be made of the same material as that of the stretchable film 1, for example. In this embodiment, the base material layer 2α of the pressure-sensitive adhesive film 2 is made of a resin material having heat shrinkability such as PET or PP. As the material of the adhesive layer 2β of the adhesive film 2, for example, a general adhesive such as silicone or acrylic, which is used for an insulating tape for electrode insulation of a general secondary battery, is used. Can do.
　本実施形態において、粘着フィルム２の引張強さは、伸縮フィルム１の引張強さよりも強くなっている。このような引張強さの大小関係は、例えば、伸縮フィルム１の厚さ及び材質と、粘着フィルム２の厚さ及び材質とを、適切に設定することによって実現することができる。 In the present embodiment, the tensile strength of the adhesive film 2 is stronger than the tensile strength of the stretchable film 1. Such a magnitude relationship between the tensile strengths can be realized, for example, by appropriately setting the thickness and material of the stretchable film 1 and the thickness and material of the adhesive film 2.
　また、本実施形態において、粘着フィルム２の粘着層２βと伸縮フィルム１との間の粘着力は、伸縮フィルム１と電池容器１０との間の接着力よりも強く、粘着フィルム２の粘着層２βと基材層２αとの間の粘着力よりも弱い。さらに、本実施形態において、粘着フィルム２の粘着層２βと基材層２αとの間の粘着力は、粘着層２βと電池容器１０との間の粘着力よりも強い。換言すると、粘着層２βと基材層２αとの間の保持力は、粘着層２βと伸縮フィルム１との間の保持力より大きい。また、粘着層２βと基材層２αとの間の保持力は、伸縮フィルム１と電池容器１０との間の保持力より大きい。このような粘着力及び保持力の大小関係は、例えば、粘着フィルム２の粘着層２βと基材層２αとの間の接触面積を、粘着層２βと伸縮フィルム１又は電池容器１０との間の接触面積よりも大きくすることで、実現することができる。 Moreover, in this embodiment, the adhesive force between the adhesive layer 2β of the adhesive film 2 and the stretchable film 1 is stronger than the adhesive force between the stretchable film 1 and the battery container 10, and the adhesive layer 2β of the adhesive film 2 It is weaker than the adhesive force between the substrate layer 2α and the substrate layer 2α. Furthermore, in this embodiment, the adhesive force between the adhesive layer 2β and the base material layer 2α of the adhesive film 2 is stronger than the adhesive force between the adhesive layer 2β and the battery container 10. In other words, the holding force between the adhesive layer 2β and the base material layer 2α is larger than the holding force between the adhesive layer 2β and the stretchable film 1. Further, the holding force between the adhesive layer 2β and the base material layer 2α is larger than the holding force between the stretchable film 1 and the battery container 10. Such a magnitude relationship between the adhesive force and the holding force is, for example, the contact area between the adhesive layer 2β and the base material layer 2α of the adhesive film 2 between the adhesive layer 2β and the stretchable film 1 or the battery container 10. This can be realized by making it larger than the contact area.
　より具体的には、例えば、粘着フィルム２の基材層２αの表面を粗化する易接着処理を施したり、伸縮フィルム１又は電池容器１０の表面粗さを低減する平滑化処理を施したりすることで、粘着フィルム２の粘着層２βに対する各部材の接触面積を増減させることができる。なお、電池容器１０の表面の平滑化処理には、例えば、電池容器１０の表面にシリコンコートなどの離型処理を施して、電池容器１０と粘着フィルム２の粘着層２βとの粘着力を相対的に低減させることを含む。 More specifically, for example, an easy adhesion process for roughening the surface of the base material layer 2α of the adhesive film 2 is performed, or a smoothing process for reducing the surface roughness of the stretchable film 1 or the battery container 10 is performed. Thereby, the contact area of each member with respect to the adhesion layer 2 (beta) of the adhesion film 2 can be increased / decreased. In addition, in the smoothing process of the surface of the battery container 10, for example, the surface of the battery container 10 is subjected to a mold release process such as silicon coating, and the adhesive force between the battery container 10 and the adhesive layer 2β of the adhesive film 2 is relatively set. Reduction.
　図２は、図１Ａに示す角形二次電池１００の電池容器１０が伸縮フィルム１及び粘着フィルム２によって絶縁被覆される前の状態を示す外観斜視図である。図３は、図２に示す絶縁被覆前の角形二次電池１００の分解斜視図である。 FIG. 2 is an external perspective view showing a state before the battery container 10 of the rectangular secondary battery 100 shown in FIG. 1A is insulation-coated with the stretchable film 1 and the adhesive film 2. FIG. 3 is an exploded perspective view of the prismatic secondary battery 100 before insulation coating shown in FIG.
　本実施形態の角形二次電池１００は、例えば、矩形箱形の電池容器１０を備える角形リチウムイオン二次電池である。電池容器１０は、開口部１１ａによって一端が開放され内部に電極群４０を収容する有底角筒状の電池缶１１と、電池缶１１の開口部１１ａを封止する電池蓋１２とを有している。電池缶１１及び電池蓋１２は、例えば、アルミニウム又はアルミニウム合金等の金属材料によって製作されている。 The prismatic secondary battery 100 of the present embodiment is, for example, a prismatic lithium ion secondary battery including a rectangular box-shaped battery container 10. The battery container 10 has a bottomed rectangular tube-shaped battery can 11 that is open at one end by an opening 11 a and accommodates the electrode group 40 therein, and a battery lid 12 that seals the opening 11 a of the battery can 11. ing. The battery can 11 and the battery lid 12 are made of a metal material such as aluminum or an aluminum alloy, for example.
　電池缶１１は、内部に収容される扁平な電極群４０に対応する扁平角形の形状を有している。電池缶１１は、底部を閉塞して電池蓋１２に対向する底壁によって形成された概ね長方形の底面１１ｂと、厚さ方向に対向する一対の側壁によって形成された幅広側面１１ｃと、幅方向に対向する一対の側壁によって形成された幅狭側面１１ｄとを有している。
電池蓋１２は、電池缶１１の長方形の開口部１１ａを封止する概ね長方形の板状の部材であり、長手方向の一端と他端に正極及び負極外部端子２０Ａ，２０Ｂが設けられている。 The battery can 11 has a flat rectangular shape corresponding to the flat electrode group 40 accommodated therein. The battery can 11 has a substantially rectangular bottom surface 11b formed by a bottom wall that closes the bottom and faces the battery lid 12, a wide side surface 11c formed by a pair of side walls facing the thickness direction, and a width direction. And a narrow side surface 11d formed by a pair of opposing side walls.
The battery lid 12 is a substantially rectangular plate-like member that seals the rectangular opening 11a of the battery can 11, and is provided with positive and negative external terminals 20A and 20B at one end and the other end in the longitudinal direction.
　正極外部端子２０Ａは、例えば、アルミニウム又はアルミニウム合金によって製作され、負極外部端子２０Ｂは、例えば、銅又は銅合金によって製作されている。以下、正極側と負極側を特に区別する必要がない場合には、正極及び負極外部端子２０Ａ，２０Ｂを一括して外部端子２０と表記する。外部端子２０は、バスバー等に溶接接合される溶接接合部２１を有している。溶接接合部２１は、概ね直方体形状を有するブロック状に形成され、下端面が電池蓋１２の上面に対向し、上端面が電池蓋１２の上面と平行になっている。
溶接接合部２１の下端面には、電池蓋１２の上面に垂直な方向に延びる柱状の接続部２１ａが設けられている。 The positive external terminal 20A is made of, for example, aluminum or an aluminum alloy, and the negative external terminal 20B is made of, for example, copper or a copper alloy. Hereinafter, when there is no need to particularly distinguish the positive electrode side and the negative electrode side, the positive electrode and the negative electrode external terminals 20A and 20B are collectively referred to as the external terminal 20. The external terminal 20 has a weld joint 21 that is welded to a bus bar or the like. The welded joint portion 21 is formed in a block shape having a substantially rectangular parallelepiped shape, with a lower end surface facing the upper surface of the battery lid 12 and an upper end surface parallel to the upper surface of the battery lid 12.
A columnar connection portion 21 a extending in a direction perpendicular to the upper surface of the battery lid 12 is provided on the lower end surface of the weld joint portion 21.
　外部端子２０と電池蓋１２との間には、ガスケット３が配置されている。ガスケット３は、例えばポリブチレンテレフタレートやポリフェニレンサルファイド、ペルフルオロアルコキシフッ素樹脂等の絶縁性を有する樹脂材料によって製作されている。ガスケット３は、外部端子２０の接続部２１ａを挿通させる貫通孔３ａと、外部端子２０の溶接接合部２１の側面の一部を覆う側壁部３ｂとを有している。 The gasket 3 is disposed between the external terminal 20 and the battery cover 12. The gasket 3 is made of an insulating resin material such as polybutylene terephthalate, polyphenylene sulfide, perfluoroalkoxy fluorine resin, or the like. The gasket 3 has a through-hole 3 a through which the connection portion 21 a of the external terminal 20 is inserted, and a side wall portion 3 b that covers a part of the side surface of the weld joint portion 21 of the external terminal 20.
　電池蓋１２は、長手方向の両端に、外部端子２０の接続部２１ａを挿通させる一対の貫通孔１２ａを有している。また、電池蓋１２は、一対の貫通孔１２ａの間の中間部に、ガス排出弁１３及び注液口１４を有している。ガス排出弁１３は、例えば、電池蓋１２を薄肉化して溝部１３ａを形成することによって設けられ、電池容器１０の内部の圧力が所定値を超えて上昇した時に開裂して内部のガスを放出することで、電池容器１０の内部の圧力を低下させる。注液口１４は、電池容器１０の内部に電解液を注入するのに用いられ、例えば、レーザ溶接によって注液栓１５が溶接されて封止されている。 The battery lid 12 has a pair of through holes 12a through which the connection portions 21a of the external terminals 20 are inserted at both ends in the longitudinal direction. Further, the battery cover 12 has a gas discharge valve 13 and a liquid injection port 14 in an intermediate portion between the pair of through holes 12a. The gas discharge valve 13 is provided, for example, by thinning the battery lid 12 to form a groove 13a, and is cleaved to release the internal gas when the internal pressure of the battery container 10 exceeds a predetermined value. As a result, the pressure inside the battery container 10 is reduced. The liquid injection port 14 is used to inject an electrolytic solution into the battery container 10, and is sealed by, for example, a liquid injection stopper 15 being welded by laser welding.
　電池蓋１２の内側の面には、外側の面に配置された正極及び負極外部端子２０Ａ，２０Ｂに対応する位置に、正極及び負極集電板３０Ａ，３０Ｂが絶縁板４を介して固定されている。正極集電板３０Ａは、例えば、アルミニウム又はアルミニウム合金によって製作され、負極集電板３０Ｂは、例えば銅又は銅合金によって製作されている。絶縁板４は、例えば、ガスケット３と同様の絶縁性を有する樹脂材料によって製作されている。以下、正極及び負極集電板３０Ａ，３０Ｂを特に区別する必要がない場合には、正極及び負極集電板３０Ａ，３０Ｂを一括して集電板３０と表記する。 On the inner surface of the battery lid 12, positive and negative current collector plates 30A and 30B are fixed via insulating plates 4 at positions corresponding to the positive and negative electrode external terminals 20A and 20B disposed on the outer surface. Yes. The positive electrode current collector plate 30A is made of, for example, aluminum or an aluminum alloy, and the negative electrode current collector plate 30B is made of, for example, copper or a copper alloy. The insulating plate 4 is made of, for example, a resin material having insulation similar to that of the gasket 3. Hereinafter, when there is no need to particularly distinguish the positive and negative current collector plates 30A and 30B, the positive and negative current collector plates 30A and 30B are collectively referred to as the current collector plate 30.
　集電板３０は、電池蓋１２の下面に対向して配置される矩形板状の基部３１と、基部３１の側端で折曲されて電池缶１１の幅広側面１１ｃに沿って底面１１ｂに向かって延びる端子部３２とを有している。電池蓋１２の内側の面すなわち下面と、集電板３０の基部３１との間には、絶縁板４が配置され、電池蓋１２と集電板３０とが電気的に絶縁されている。集電板３０の基部３１と絶縁板４は、それぞれ外部端子２０の接続部２１ａを挿通させる貫通孔３１ａ，４ａを有している。 The current collecting plate 30 is a rectangular plate-shaped base portion 31 that is disposed to face the lower surface of the battery lid 12, and is bent at a side end of the base portion 31 so as to extend toward the bottom surface 11 b along the wide side surface 11 c of the battery can 11. And a terminal portion 32 extending in the direction. The insulating plate 4 is disposed between the inner surface of the battery lid 12, that is, the lower surface, and the base 31 of the current collector plate 30, so that the battery lid 12 and the current collector plate 30 are electrically insulated. The base 31 and the insulating plate 4 of the current collector plate 30 have through holes 31a and 4a through which the connection portions 21a of the external terminals 20 are inserted, respectively.
　外部端子２０、ガスケット３、絶縁板４及び集電板３０は、電池蓋１２に対してかしめ固定されている。具体的には、ガスケット３の貫通孔３ａ、電池蓋１２の貫通孔１２ａ、絶縁板４の貫通孔４ａ、及び集電板３０の基部３１の貫通孔３１ａに、外部端子２０の接続部２１ａを挿通させた後、接続部２１ａの先端を塑性変形させて拡径し、かしめ部を形成する。これにより、外部端子２０、ガスケット３、絶縁板４及び集電板３０が電池蓋１２に対してかしめ固定され、外部端子２０と集電板３０とが電気的に接続される。また、ガスケット３及び絶縁板４によって、外部端子２０及び集電板３０が電池蓋１２に対して電気的に絶縁される。 External terminal 20, gasket 3, insulating plate 4, and current collector plate 30 are caulked and fixed to battery lid 12. Specifically, the connecting portion 21 a of the external terminal 20 is connected to the through hole 3 a of the gasket 3, the through hole 12 a of the battery lid 12, the through hole 4 a of the insulating plate 4, and the through hole 31 a of the base 31 of the current collector plate 30. After the insertion, the tip of the connecting portion 21a is plastically deformed to expand the diameter, thereby forming a caulking portion. Thereby, the external terminal 20, the gasket 3, the insulating plate 4, and the current collector plate 30 are caulked and fixed to the battery lid 12, and the external terminal 20 and the current collector plate 30 are electrically connected. Further, the external terminals 20 and the current collector plate 30 are electrically insulated from the battery lid 12 by the gasket 3 and the insulating plate 4.
　電極群４０は、正極及び負極電極４１，４２（図３参照）の箔露出部４１ｃ，４２ｃを束ね、例えば、超音波圧接又は抵抗溶接等によって、それぞれ正極及び負極集電板３０Ａ，３０Ｂの端子部３２に接合されている。これにより、電極群４０は、集電板３０を介して外部端子２０と電気的に接続され、集電板３０を介して電池蓋１２に固定されている。
電極群４０は、例えば、ポリプロピレン等の合成樹脂製の絶縁保護フィルム５によって覆われて電池缶１１に対して電気的に絶縁され、電池缶１１の開口部１１ａから電池缶１１内部に挿入されている。その後、例えば、レーザ溶接によって、電池蓋１２を電池缶１１の開口部１１ａの全周に亘って溶接し、電池缶１１の開口部１１ａを電池蓋１２によって封止することで、電池容器１０が形成される。 The electrode group 40 bundles the foil exposed portions 41c and 42c of the positive and negative electrodes 41 and 42 (see FIG. 3), and, for example, the terminals of the positive and negative current collector plates 30A and 30B by ultrasonic welding or resistance welding, respectively. It is joined to the part 32. Thus, the electrode group 40 is electrically connected to the external terminal 20 via the current collector plate 30 and is fixed to the battery lid 12 via the current collector plate 30.
The electrode group 40 is covered with an insulating protective film 5 made of synthetic resin such as polypropylene and electrically insulated from the battery can 11, and is inserted into the battery can 11 from the opening 11 a of the battery can 11. Yes. Thereafter, for example, the battery lid 12 is welded over the entire circumference of the opening 11a of the battery can 11 by laser welding, and the opening 11a of the battery can 11 is sealed with the battery lid 12, so that the battery container 10 is It is formed.
　その後、電池蓋１２の注液口１４を介して電池容器１０の内部に非水電解液を注入して電池缶１１に非水電解液を収容し、例えば、レーザ溶接によって注液栓１５を注液口１４に接合して封止することで、電池容器１０が密閉されている。電池容器１０の内部に注入する非水電解液としては、例えば、エチレンカーボネート等の炭酸エステル系の有機溶媒に、６フッ化リン酸リチウム（ＬｉＰＦ６）等のリチウム塩が溶解された非水電解液を適用することができる。 Thereafter, the nonaqueous electrolytic solution is injected into the battery container 10 through the liquid injection port 14 of the battery lid 12 to accommodate the nonaqueous electrolytic solution in the battery can 11, and the injection plug 15 is injected by laser welding, for example. The battery container 10 is hermetically sealed by bonding to the liquid port 14 and sealing. As a nonaqueous electrolytic solution to be injected into the battery container 10, for example, a nonaqueous electrolytic solution in which a lithium salt such as lithium hexafluorophosphate (LiPF 6 ) is dissolved in a carbonic acid ester-based organic solvent such as ethylene carbonate. Liquid can be applied.
　図４は、図３に示す電極群４０の一部を展開した分解斜視図である。 FIG. 4 is an exploded perspective view in which a part of the electrode group 40 shown in FIG. 3 is developed.
　電極群４０は、セパレータ４３，４４を介在させて積層した正極及び負極電極４１，４２を捲回軸Ａに平行な軸芯の周りに捲回して扁平形状に成形した捲回電極群である。セパレータ４３，４４は、正極電極４１と負極電極４２との間を絶縁すると共に、最外周に捲回された負極電極４２の外側にもセパレータ４４が捲回されている。セパレータ４３，４４は、例えば、多孔質のポリエチレン樹脂によって製作されている。 The electrode group 40 is a wound electrode group in which a positive electrode and a negative electrode 41, 42 laminated with separators 43 and 44 interposed therebetween are wound around an axis parallel to the winding axis A and formed into a flat shape. The separators 43 and 44 insulate the positive electrode 41 and the negative electrode 42, and the separator 44 is wound outside the negative electrode 42 wound around the outermost periphery. The separators 43 and 44 are made of, for example, a porous polyethylene resin.
　電極群４０は、正極及び負極電極４１，４２が平坦に積層された厚さ方向両側の一対の平面部４０ａと、平面部４０ａの両側で正極及び負極電極４１，４２が湾曲して積層された半円筒状の一対の湾曲部４０ｂを有している。電極群４０は、捲回軸Ａが電池缶１１の底面１１ｂ及び幅広側面１１ｃと平行になるように電池缶１１内に挿入され、一対の平面部４０ａが電池缶１１の一対の幅広側面１１ｃに対向して配置され、一対の湾曲部４０ｂが電池蓋１２及び電池缶１１の底面１１ｂに対向して配置される。 The electrode group 40 has a pair of flat portions 40a on both sides in the thickness direction in which the positive and negative electrodes 41 and 42 are flatly laminated, and the positive and negative electrodes 41 and 42 are curved and laminated on both sides of the flat portion 40a. It has a pair of semi-cylindrical curved portions 40b. The electrode group 40 is inserted into the battery can 11 so that the winding axis A is parallel to the bottom surface 11 b and the wide side surface 11 c of the battery can 11, and the pair of flat portions 40 a are formed on the pair of wide side surfaces 11 c of the battery can 11. A pair of curved portions 40 b are disposed to face each other and face the battery lid 12 and the bottom surface 11 b of the battery can 11.
　正極電極４１は、正極集電体である正極箔４１ａと、正極箔４１ａの両面に塗布された正極活物質合剤からなる正極合剤層４１ｂとを有している。正極電極４１の幅方向の一側は、正極合剤層４１ｂが形成されず、正極箔４１ａが露出した箔露出部４１ｃとされている。正極電極４１は、箔露出部４１ｃが負極電極４２の箔露出部４２ｃと捲回軸Ａ方向の反対側に配置されて、捲回軸Ａの周りに捲回されている。 The positive electrode 41 has a positive electrode foil 41a that is a positive electrode current collector, and a positive electrode mixture layer 41b made of a positive electrode active material mixture applied to both surfaces of the positive electrode foil 41a. One side of the positive electrode 41 in the width direction is a foil exposed portion 41c where the positive electrode mixture layer 41b is not formed and the positive foil 41a is exposed. The positive electrode 41 is wound around the winding axis A, with the foil exposed portion 41 c disposed on the opposite side of the foil exposed portion 42 c of the negative electrode 42 in the winding axis A direction.
　正極電極４１は、例えば、正極活物質に導電材、結着剤及び分散溶媒を添加して混練した正極活物質合剤を、幅方向の一側を除いて正極箔４１ａの両面に塗布し、乾燥、プレス、裁断することによって製作することができる。正極箔４１ａとしては、例えば、厚さ約２０μｍのアルミニウム箔を用いることができる。正極箔４１ａの厚みを含まない正極合剤層４１ｂの厚さは、例えば、約９０μｍである。 The positive electrode 41, for example, a positive electrode active material mixture kneaded by adding a conductive material, a binder and a dispersion solvent to the positive electrode active material, is applied to both surfaces of the positive electrode foil 41a except for one side in the width direction, It can be produced by drying, pressing and cutting. As the positive electrode foil 41a, for example, an aluminum foil with a thickness of about 20 μm can be used. The thickness of the positive electrode mixture layer 41b not including the thickness of the positive electrode foil 41a is, for example, about 90 μm.
　正極活物質合剤の材料としては、例えば、正極活物質として１００重量部のマンガン酸リチウム（化学式ＬｉＭｎ２Ｏ４）を、導電材として１０重量部の鱗片状黒鉛を、結着剤として１０重量部のポリフッ化ビニリデン（以下、ＰＶＤＦという。）を、分散溶媒としてＮ－メチルピロリドン（以下、ＮＭＰという。）を、それぞれ用いることができる。正極活物質は、前記したマンガン酸リチウムに限定されず、例えば、スピネル結晶構造を有する他のマンガン酸リチウム、一部を金属元素で置換又はドープしたリチウムマンガン複合酸化物を用いてもよい。また、正極活物質として、層状結晶構造を有するコバルト酸リチウムやチタン酸リチウム、及びこれらの一部を金属元素で置換又はドープしたリチウム－金属複合酸化物を用いてもよい。 As a material of the positive electrode active material mixture, for example, 100 parts by weight of lithium manganate (chemical formula LiMn 2 O 4 ) is used as the positive electrode active material, 10 parts by weight of flaky graphite as the conductive material, and 10% by weight as the binder. Part of polyvinylidene fluoride (hereinafter referred to as PVDF) and N-methylpyrrolidone (hereinafter referred to as NMP) can be used as a dispersion solvent. The positive electrode active material is not limited to the above-described lithium manganate. For example, another lithium manganate having a spinel crystal structure, or a lithium manganese composite oxide partially substituted or doped with a metal element may be used. Further, as the positive electrode active material, lithium cobalt oxide or lithium titanate having a layered crystal structure, or a lithium-metal composite oxide in which a part thereof is substituted or doped with a metal element may be used.
　負極電極４２は、負極集電体である負極箔４２ａと、負極箔４２ａの両面に塗布された負極活物質合剤からなる負極合剤層４２ｂとを有している。負極電極４２の幅方向の一側は、負極合剤層４２ｂが形成されず、負極箔４２ａが露出した箔露出部４２ｃとされている。負極電極４２は、その箔露出部４２ｃが正極電極４１の箔露出部４１ｃと捲回軸Ａ方向の反対側に配置されて、捲回軸Ａ周りに捲回されている。 The negative electrode 42 has a negative electrode foil 42a which is a negative electrode current collector, and a negative electrode mixture layer 42b made of a negative electrode active material mixture coated on both surfaces of the negative electrode foil 42a. One side in the width direction of the negative electrode 42 is a foil exposed portion 42c where the negative electrode mixture layer 42b is not formed and the negative foil 42a is exposed. The negative electrode 42 is wound around the winding axis A such that the foil exposed portion 42 c is disposed on the opposite side of the foil exposed portion 41 c of the positive electrode 41 in the winding axis A direction.
　負極電極４２は、例えば、負極活物質に結着剤及び分散溶媒を添加して混練した負極活物質合剤を、幅方向の一側を除く負極箔４２ａの両面に塗布し、乾燥、プレス、裁断することによって製作することができる。負極箔４２ａとしては、例えば、厚さ約１０μｍの銅箔を用いることができる。負極箔４２ａの厚みを含まない負極合剤層４２ｂの厚さは、例えば、約７０μｍである。 For example, the negative electrode 42 is prepared by applying a negative electrode active material mixture kneaded by adding a binder and a dispersion solvent to the negative electrode active material on both sides of the negative electrode foil 42a except for one side in the width direction, drying, pressing, It can be produced by cutting. As the negative electrode foil 42a, for example, a copper foil having a thickness of about 10 μm can be used. The thickness of the negative electrode mixture layer 42b not including the thickness of the negative electrode foil 42a is, for example, about 70 μm.
　負極活物質合剤の材料としては、例えば、負極活物質として１００重量部の非晶質炭素粉末を、結着剤として１０重量部のＰＶＤＦを、分散溶媒としてＮＭＰをそれぞれ用いることができる。負極活物質は、前記した非晶質炭素に限定されず、リチウムイオンを挿入、脱離可能な天然黒鉛や、人造の各種黒鉛材、コークスなどの炭素質材料やＳｉやＳｎなどの化合物（例えば、ＳｉＯ、ＴｉＳｉ２等）、又はそれらの複合材料を用いてもよい。
負極活物質の粒子形状についても特に限定されず、鱗片状、球状、繊維状又は塊状等の粒子形状を適宜選択することができる。 As a material for the negative electrode active material mixture, for example, 100 parts by weight of amorphous carbon powder as the negative electrode active material, 10 parts by weight of PVDF as the binder, and NMP as the dispersion solvent can be used. The negative electrode active material is not limited to the above-mentioned amorphous carbon, and natural graphite capable of inserting and removing lithium ions, various artificial graphite materials, carbonaceous materials such as coke, and compounds such as Si and Sn (for example, , SiO, TiSi 2 or the like), or a composite material thereof.
The particle shape of the negative electrode active material is not particularly limited, and a particle shape such as a scale shape, a spherical shape, a fiber shape, or a lump shape can be appropriately selected.
　なお、前記した正極及び負極合剤層４１ｂ，４２ｂに用いる結着材は、ＰＶＤＦに限定されない。前記した結着材として、例えば、ポリテトラフルオロエチレン（ＰＴＦＥ）、ポリエチレン、ポリスチレン、ポリブタジエン、ブチルゴム、ニトリルゴム、スチレンブタジエンゴム、多硫化ゴム、ニトロセルロース、シアノエチルセルロース、各種ラテックス、アクリロニトリル、フッ化ビニル、フッ化ビニリデン、フッ化プロピレン、フッ化クロロプレン、アクリル系樹脂などの重合体及びこれらの混合体などを用いてもよい。 In addition, the binder used for the above-described positive electrode and negative electrode mixture layers 41b and 42b is not limited to PVDF. Examples of the binder include polytetrafluoroethylene (PTFE), polyethylene, polystyrene, polybutadiene, butyl rubber, nitrile rubber, styrene butadiene rubber, polysulfide rubber, nitrocellulose, cyanoethyl cellulose, various latexes, acrylonitrile, and vinyl fluoride. Polymers such as vinylidene fluoride, propylene fluoride, chloroprene fluoride, and acrylic resins, and mixtures thereof may be used.
　また、セパレータ４３，４４を介在させて正極電極４１及び負極電極４２を重ねて捲回する際の軸芯は、例えば、正極箔４１ａ、負極箔４２ａ、セパレータ４３，４４のいずれよりも曲げ剛性の高い樹脂シートを捲回したものを用いることができる。 In addition, the axial core when winding the positive electrode 41 and the negative electrode 42 with the separators 43 and 44 interposed therebetween is, for example, more flexible than the positive foil 41a, the negative foil 42a, and the separators 43 and 44. A roll of a high resin sheet can be used.
　電極群４０の捲回軸Ａ方向において、負極電極４２の負極合剤層４２ｂの幅は、正極電極４１の正極合剤層４１ｂの幅よりも広くなっている。また、電極群４０の最内周と最外周には負極電極４２が捲回されている。これにより、正極合剤層４１ｂは、電極群４０の最内周から最外周まで負極合剤層４２ｂの間に挟まれている。 In the winding axis A direction of the electrode group 40, the width of the negative electrode mixture layer 42b of the negative electrode 42 is wider than the width of the positive electrode mixture layer 41b of the positive electrode 41. A negative electrode 42 is wound around the innermost and outermost circumferences of the electrode group 40. Thus, the positive electrode mixture layer 41b is sandwiched between the negative electrode mixture layer 42b from the innermost periphery to the outermost periphery of the electrode group 40.
　正極電極４１及び負極電極４２の箔露出部４１ｃ，４２ｃはそれぞれ電極群４０の平面部４０ａで束ねられ、例えば超音波圧接、抵抗溶接等によって、集電板３０の端子部３２に接合される。これにより、正極及び負極外部端子２０Ａ，２０Ｂが、それぞれ正極及び負極集電板３０Ａ，３０Ｂを介して、電極群４０を構成する正極及び負極電極４１，４２とそれぞれ電気的に接続される。 The foil exposed portions 41c and 42c of the positive electrode 41 and the negative electrode 42 are respectively bundled by the flat portion 40a of the electrode group 40, and are joined to the terminal portion 32 of the current collector plate 30 by, for example, ultrasonic pressure welding or resistance welding. Accordingly, the positive and negative external terminals 20A and 20B are electrically connected to the positive and negative electrodes 41 and 42 constituting the electrode group 40 via the positive and negative current collector plates 30A and 30B, respectively.
　なお、電極群４０の捲回軸Ａ方向において、セパレータ４３，４４の幅は負極合剤層４２ｂの幅よりも広いが、正極電極４１及び負極電極４２の箔露出部４１ｃ，４２ｃは、それぞれセパレータ４３，４４の幅方向端部よりも幅方向外側に突出している。したがって、セパレータ４３，４４は、箔露出部４１ｃ，４２ｃを束ねて溶接する際の支障にはならない。 In addition, in the winding axis A direction of the electrode group 40, the width of the separators 43 and 44 is wider than the width of the negative electrode mixture layer 42b, but the foil exposed portions 41c and 42c of the positive electrode 41 and the negative electrode 42 are respectively separators. It protrudes outward in the width direction from the ends in the width direction of 43 and 44. Therefore, the separators 43 and 44 do not hinder when the foil exposed portions 41c and 42c are bundled and welded.
　このような構成を有する角形二次電池１００は、例えば、外部端子２０の溶接接合部２１の上面にバスバーが溶接され、複数の角形二次電池１００を直列に接続した組電池として用いられる。角形二次電池１００は、例えば、発電機等の電力供給源から供給された電力を、外部端子２０及び集電板３０を介して電極群４０に蓄積することで充電される。また、角形二次電池１００は、電極群４０に蓄積した電力を、集電板３０及び外部端子２０を介して、例えば、モーター等の電力を消費する装置に供給する。 The prismatic secondary battery 100 having such a configuration is used, for example, as an assembled battery in which a bus bar is welded to the upper surface of the welded joint portion 21 of the external terminal 20 and a plurality of prismatic secondary batteries 100 are connected in series. The prismatic secondary battery 100 is charged by, for example, accumulating electric power supplied from a power supply source such as a generator in the electrode group 40 via the external terminal 20 and the current collector plate 30. In addition, the prismatic secondary battery 100 supplies the power stored in the electrode group 40 to a device that consumes power, such as a motor, via the current collector plate 30 and the external terminal 20.
　また、角形二次電池１００は、何らかの異常によって電池容器１０の内部の圧力が上昇して所定の圧力を超えると、電池蓋１２に設けられたガス排出弁１３が開放され、電池容器１０の内部のガスを排出して内部の圧力を低減させることができる。これにより、角形二次電池１００の安全性が確保されている。 In addition, when the internal pressure of the battery case 10 increases due to some abnormality and exceeds a predetermined pressure, the prismatic secondary battery 100 opens the gas discharge valve 13 provided in the battery cover 12, and the inside of the battery case 10. This gas can be discharged to reduce the internal pressure. Thereby, the safety | security of the square secondary battery 100 is ensured.
（角形二次電池の絶縁被覆工程）
　図５Ａ及び図５Ｂは、図１Ａに示す角形二次電池１００の絶縁被覆工程を説明する斜視図である。 (Insulation coating process for prismatic secondary battery)
5A and 5B are perspective views for explaining an insulating coating process of the prismatic secondary battery 100 shown in FIG. 1A.
　まず、図５Ａに示すように、絶縁被覆前の角形二次電池１００と、角形二次電池１００の電池容器１０を覆うための伸縮フィルム１を用意する。そして、電池容器１０を構成する電池缶１１の底面１１ｂ側に、伸縮フィルム１を配置する。ここで、本実施形態の伸縮フィルム１は、前述の熱可塑性を有する樹脂材料によって製作されている。そのため、例えば、ヒーター等によって伸縮フィルム１を加熱して軟化させた後、吸引装置等によって電池容器１０の電池蓋１２側から空気を吸引することで、軟化した伸縮フィルム１によって電池容器１０を電池缶１１の底面１１ｂ側から包み込むことができる。 First, as shown in FIG. 5A, the prismatic secondary battery 100 before insulation coating and the stretchable film 1 for covering the battery container 10 of the prismatic secondary battery 100 are prepared. And the elastic film 1 is arrange | positioned at the bottom face 11b side of the battery can 11 which comprises the battery container 10. FIG. Here, the stretchable film 1 of this embodiment is manufactured by the resin material which has the above-mentioned thermoplasticity. Therefore, for example, after the stretchable film 1 is heated and softened by a heater or the like, air is sucked from the battery lid 12 side of the battery container 10 by a suction device or the like, so that the battery container 10 is charged by the softened stretchable film 1. The can 11 can be wrapped from the bottom surface 11b side.
　これにより、図５Ｂに示すように、絶縁性の伸縮フィルム１は、一端に開口１ａを有し該開口１ａから電池容器１０の一部を露出させた状態で電池容器１０を覆う。このように、加熱して軟化させた伸縮フィルム１で電池容器１０を覆うことで、伸縮フィルム１と電池容器１０とを隙間なく密着させ、伸縮フィルム１を電池容器１０に対して接着することができる。本実施形態において、伸縮フィルム１は、電池缶１１の底面１１ｂと一対の幅広側面１１ｃと一対の幅狭側面１１ｄとに密着している。 Thereby, as shown in FIG. 5B, the insulating stretchable film 1 has an opening 1a at one end and covers the battery container 10 with a part of the battery container 10 exposed from the opening 1a. Thus, by covering the battery container 10 with the stretchable film 1 softened by heating, the stretchable film 1 and the battery container 10 can be brought into close contact with each other and the stretchable film 1 can be adhered to the battery container 10. it can. In the present embodiment, the stretchable film 1 is in close contact with the bottom surface 11b of the battery can 11, the pair of wide side surfaces 11c, and the pair of narrow side surfaces 11d.
　すなわち、本実施形態において、伸縮フィルム１は、開口１ａから電池缶１１の開口部１１ａの近傍の上端部と電池蓋１２の全体を露出させ、電池蓋１２及び電池缶１１の上端部を除く電池容器１０の外表面の大部分を覆っている。換言すると、伸縮フィルム１は、開口１ａから、電池蓋１２と、電池缶１１の一対の幅広側面１１ｃの一部と、電池缶１１の一対の幅狭側面１１ｄの一部とを露出させ、電池容器１０のその他の部分を覆っている。 That is, in the present embodiment, the stretchable film 1 exposes the upper end portion of the battery can 11 in the vicinity of the opening portion 11a and the entire battery lid 12 from the opening 1a, and excludes the battery lid 12 and the upper end portion of the battery can 11 from the battery. Most of the outer surface of the container 10 is covered. In other words, the stretchable film 1 exposes the battery lid 12, a part of the pair of wide side surfaces 11c of the battery can 11, and a part of the pair of narrow side surfaces 11d of the battery can 11 from the opening 1a. The other part of the container 10 is covered.
　なお、伸縮フィルム１は、電池缶１１の全体、すなわち、電池缶１１の底面１１ｂから電池缶１１と電池蓋１２との間の溶接部までを覆うようにしてもよい。しかし、電池缶１１と電池蓋１２との間の溶接部は、電池容器１０のその他の部分よりも表面粗さや凹凸が大きくなる場合がある。そのため、伸縮フィルム１と電池容器１０との密着性を向上させて剥がれを防止する観点から、伸縮フィルム１によって電池缶１１と電池蓋１２との間の溶接部を被覆しないことが好ましい。 The stretchable film 1 may cover the entire battery can 11, that is, the welded portion between the battery can 11 and the battery lid 12 from the bottom surface 11 b of the battery can 11. However, the welded portion between the battery can 11 and the battery lid 12 may have a larger surface roughness or unevenness than other portions of the battery container 10. Therefore, it is preferable that the welded part between the battery can 11 and the battery lid 12 is not covered with the stretchable film 1 from the viewpoint of improving the adhesion between the stretchable film 1 and the battery container 10 and preventing peeling.
　電池缶１１と電池蓋１２との間の溶接部を伸縮フィルム１から露出させる場合には、溶接部が露出するように予め伸縮フィルム１の大きさを設定してもよいが、例えば、以下の手順によって溶接部を露出させるようにしてもよい。すなわち、まず、伸縮フィルム１によって電池缶１１の底面１１ｂから電池缶１１と電池蓋１２との間の溶接部までを覆う。
その後、電池缶１１と電池蓋１２との間の溶接部よりも電池缶１１の底面１１ｂ側の位置で、電池蓋１２に沿って伸縮フィルム１を切断し、伸縮フィルム１の溶接部を覆う部分を取り除くようにしてもよい。 When the welded portion between the battery can 11 and the battery lid 12 is exposed from the stretchable film 1, the size of the stretchable film 1 may be set in advance so that the welded portion is exposed. You may make it expose a welding part according to a procedure. That is, first, the stretchable film 1 covers the bottom surface 11 b of the battery can 11 to the welded portion between the battery can 11 and the battery lid 12.
Thereafter, the stretchable film 1 is cut along the battery lid 12 at a position closer to the bottom surface 11b of the battery can 11 than the welded portion between the battery can 11 and the battery lid 12, and the welded portion of the stretchable film 1 is covered. You may make it remove.
　以上のように伸縮フィルム１によって電池容器１０を覆った後、伸縮フィルム１の開口１ａから露出した電池容器１０を覆う粘着フィルム２を用意する。そして、角形二次電池１００の電池容器１０を構成する電池蓋１２側に、粘着フィルム２を配置する。図１Ａ及び図１Ｂに示すように、粘着フィルム２は、伸縮フィルム１の開口１ａから露出した電池容器１０を覆うとともに、伸縮フィルム１の開口１ａの縁部１ｂを覆うのに十分な面積と形状を有している。 After the battery container 10 is covered with the stretchable film 1 as described above, an adhesive film 2 that covers the battery container 10 exposed from the opening 1a of the stretchable film 1 is prepared. And the adhesive film 2 is arrange | positioned at the battery cover 12 side which comprises the battery container 10 of the square secondary battery 100. FIG. As shown in FIGS. 1A and 1B, the adhesive film 2 covers the battery container 10 exposed from the opening 1 a of the stretchable film 1 and has an area and shape sufficient to cover the edge 1 b of the opening 1 a of the stretchable film 1. have.
　具体的には、図５Ｂに示すように、粘着フィルム２は、電池容器１０の幅Ｗ方向を長手方向、厚さＴ方向を短手方向とする長方形の形状を有している。粘着フィルム２の短手方向の寸法Ｄ１は、伸縮フィルム１の開口１ａから露出した電池容器１０の高さＨの２倍と厚さＴとの和よりも十分に大きい。また、粘着フィルム２の長手方向の寸法Ｄ２は、露出した電池容器１０の高さＨの２倍と幅Ｗとの和よりも十分に大きい。 Specifically, as shown in FIG. 5B, the adhesive film 2 has a rectangular shape in which the width W direction of the battery container 10 is the longitudinal direction and the thickness T direction is the short direction. The dimension D1 in the short direction of the adhesive film 2 is sufficiently larger than the sum of twice the height H of the battery container 10 exposed from the opening 1a of the stretchable film 1 and the thickness T. Moreover, the dimension D2 in the longitudinal direction of the adhesive film 2 is sufficiently larger than the sum of twice the height H of the exposed battery container 10 and the width W.
　本実施形態において、粘着フィルム２の短手方向の寸法Ｄ１は、露出した角形二次電池１００の高さＨの４倍と厚さＴとの和よりも大きく、概ね高さＨの６倍と厚さＴとの和に等しくなっている。また、本実施形態において、粘着フィルム２の長手方向の寸法Ｄ２は、露出した角形二次電池１００の高さＨの６倍と幅Ｗの和よりも大きく、概ね高さＨの１０倍と厚さＴの和と等しくなっている。 In this embodiment, the dimension D1 in the short direction of the adhesive film 2 is larger than the sum of the height H and the thickness T of the exposed square secondary battery 100, and is approximately 6 times the height H. It is equal to the sum of the thickness T. Further, in this embodiment, the dimension D2 in the longitudinal direction of the adhesive film 2 is larger than the sum of the height H and the width W of the exposed square secondary battery 100, and approximately 10 times the height H and a thickness. It is equal to the sum of T.
　また、本実施形態において、粘着フィルム２は、外部端子２０に対応する位置に、外部端子２０を露出させる貫通孔２ａを有している。また、本実施形態において、粘着フィルム２は、ガス排出弁１３に対応する位置に、ガス排出弁１３の少なくとも一部を露出させる貫通孔２ｂを有している。本実施形態において、貫通孔２ｂは、ガス排出弁１３の中央部にその長手方向に沿って延びる丸長孔状に形成され、ガス排出弁１３の一部、すなわち中央部を露出させている。なお、貫通孔２ｂは、ガス排出弁１３の全体を露出させる大きさに形成してもよい。 In this embodiment, the adhesive film 2 has a through hole 2 a that exposes the external terminal 20 at a position corresponding to the external terminal 20. Moreover, in this embodiment, the adhesive film 2 has the through-hole 2b which exposes at least one part of the gas exhaust valve 13 in the position corresponding to the gas exhaust valve 13. As shown in FIG. In this embodiment, the through-hole 2b is formed in the center part of the gas exhaust valve 13 in the shape of a round long hole extending along the longitudinal direction, and a part of the gas exhaust valve 13, that is, the central part is exposed. The through hole 2b may be formed in a size that exposes the entire gas discharge valve 13.
　また、電池蓋１２又は電池缶１１に角形二次電池１００の固体識別情報を含む二次元バーコード等の情報表示部が刻印又は印字されている場合には、粘着フィルム２は、情報表示部を露出させる貫通孔を有してもよい。なお、粘着フィルム２が透明又は半透明である場合には、粘着フィルム２が情報表示部を露出させる貫通孔を有しなくてもよい。また、粘着フィルム２は、着色されていてもよい。この場合、例えば、角形二次電池１００の仕様や納品先に応じて、粘着フィルム２の色を異ならせることができる。また、粘着フィルム２は、正極外部端子２０Ａ側と負極外部端子２０Ｂ側とで異なる色に着色されていてもよい。 In addition, when an information display unit such as a two-dimensional barcode including solid identification information of the square secondary battery 100 is stamped or printed on the battery lid 12 or the battery can 11, the adhesive film 2 has an information display unit. You may have a through-hole to expose. In addition, when the adhesive film 2 is transparent or translucent, the adhesive film 2 does not need to have a through-hole which exposes an information display part. Moreover, the adhesive film 2 may be colored. In this case, for example, the color of the adhesive film 2 can be varied according to the specifications of the rectangular secondary battery 100 and the delivery destination. Further, the adhesive film 2 may be colored in different colors on the positive electrode external terminal 20A side and the negative electrode external terminal 20B side.
　例えば、以下の手順により、粘着フィルム２によって伸縮フィルム１の開口１ａから露出した電池容器１０を覆うとともに伸縮フィルム１の開口１ａの縁部１ｂを覆うことができる。まず、図５Ｂに示すように、粘着フィルム２を広げた状態で、電池蓋１２に対向させ、貫通孔２ａ及び貫通孔２ｂと、外部端子２０及びガス排出弁１３とを位置合わせする。次に、粘着フィルム２を電池蓋１２の上面に貼り付け、貫通孔２ａ及び貫通孔２ｂから外部端子２０及びガス排出弁１３を露出させる。これにより、伸縮フィルム１の開口１ａから露出した電池容器１０の一部である電池蓋１２が粘着フィルム２によって覆われる。 For example, the adhesive film 2 can cover the battery container 10 exposed from the opening 1a of the stretchable film 1 and the edge 1b of the opening 1a of the stretchable film 1 by the following procedure. First, as shown in FIG. 5B, in a state where the adhesive film 2 is spread, the battery lid 12 is opposed to the through hole 2a and the through hole 2b, and the external terminal 20 and the gas discharge valve 13 are aligned. Next, the adhesive film 2 is affixed on the upper surface of the battery cover 12, and the external terminal 20 and the gas discharge valve 13 are exposed from the through hole 2a and the through hole 2b. Thereby, the battery cover 12 which is a part of the battery container 10 exposed from the opening 1 a of the stretchable film 1 is covered with the adhesive film 2.
　次に、電池容器１０の幅Ｗ方向にはみ出した粘着フィルム２の長手方向の両端部を折目２ｃで山折りにして、下方、すなわち、電池缶１１の底面１１ｂに向けて折り返す。そして折り返した粘着フィルム２の短手方向の中央部を、電池缶１１の一対の幅狭側面１１ｄ及び伸縮フィルム１に貼り付ける。これにより、伸縮フィルム１の開口１ａから露出した電池容器１０の一部である電池缶１１の一対の幅狭側面１１ｄの電池蓋１２側の上端部と、一対の幅狭側面１１ｄ上の伸縮フィルム１の開口１ａの縁部１ｂとが、粘着フィルム２によって覆われる。 Next, both ends in the longitudinal direction of the adhesive film 2 protruding in the width W direction of the battery container 10 are folded at a crease 2 c and folded downward, that is, toward the bottom surface 11 b of the battery can 11. And the center part of the transversal direction of the adhesive film 2 turned back is affixed on a pair of narrow side surface 11d and the expansion-contraction film 1 of the battery can 11. FIG. Thereby, the upper end part by the side of the battery lid 12 of a pair of narrow side surface 11d of the battery can 11 which is a part of the battery container 10 exposed from the opening 1a of the stretch film 1, and the stretch film on the pair of narrow side surface 11d An edge 1 b of one opening 1 a is covered with an adhesive film 2.
　次に、電池蓋１２から電池容器１０の厚さＴ方向にはみ出した粘着フィルム２の短手方向の両側部を、折目２ｄで山折りにして下方に向けて折り返し、折り返した粘着フィルム２の長手方向の両端部を除く中間部を、電池缶１１の幅広側面１１ｃ及び伸縮フィルム１に貼り付ける。それと同時に、粘着フィルム２を折目２ｅで山折りにするとともに、電池缶１１の幅広側面１１ｃと幅狭側面１１ｄとの間の角部の折目２ｃで谷折りにして、折目２ｅで折り返されて対向した部分の粘着層２β同士を貼り合わせる。 Next, both sides in the short direction of the adhesive film 2 that protrudes from the battery lid 12 in the thickness T direction of the battery container 10 are folded in a fold line 2d and folded downward, and the folded adhesive film 2 The intermediate part excluding both ends in the longitudinal direction is attached to the wide side surface 11 c of the battery can 11 and the stretchable film 1. At the same time, the adhesive film 2 is folded in a fold at the crease 2e, at the corner fold 2c between the wide side surface 11c and the narrow side surface 11d of the battery can 11, and then folded at the crease 2e. Then, the adhesive layers 2β at the opposed portions are bonded together.
　これにより、伸縮フィルム１の開口１ａから露出した電池容器１０の一部である電池缶１１の一対の幅広側面１１ｃの電池蓋１２側の上端部と、一対の幅広側面１１ｃ上の伸縮フィルム１の開口１ａの縁部１ｂとが、粘着フィルム２によって覆われる。このとき、電池缶１１の幅狭側面１１ｄの両側にはみ出した粘着フィルム２には、折目２ｅで折り返されて重なった粘着フィルム２の粘着層２βが貼り合わされた三角形の領域と、その下方側で粘着層２βが露出した矩形の領域とが形成されている。 Thereby, the upper end part of the battery lid 11 side of the pair of wide side surfaces 11c of the battery can 11 that is a part of the battery case 10 exposed from the opening 1a of the stretch film 1 and the stretch film 1 on the pair of wide side surfaces 11c. The edge 1 b of the opening 1 a is covered with the adhesive film 2. At this time, the adhesive film 2 that protrudes on both sides of the narrow side surface 11d of the battery can 11 has a triangular region in which the adhesive layer 2β of the adhesive film 2 folded and overlapped at the fold 2e is bonded, and the lower side thereof Thus, a rectangular region where the adhesive layer 2β is exposed is formed.
　最後に、幅狭側面１１ｄの両側にはみ出した粘着フィルム２を、折目２ｄで電池容器１０の幅Ｗ方向の中央部に向けて折り返し、粘着層２βが露出した矩形の領域を電池缶１１の幅広側面１１ｃ上の伸縮フィルム１に貼り付ける。以上により、図１Ａに示す角形二次電池１００を得ることができる。なお、粘着フィルム２は、折目２ｃと折目２ｅとの間の三角形の領域を予め切り欠いておいてもよい。 Finally, the adhesive film 2 that protrudes on both sides of the narrow side surface 11d is folded back toward the center in the width W direction of the battery container 10 at the fold 2d, and the rectangular region where the adhesive layer 2β is exposed is removed from the battery can 11. It affixes on the elastic film 1 on the wide side surface 11c. As described above, the prismatic secondary battery 100 shown in FIG. 1A can be obtained. In addition, the adhesive film 2 may cut out beforehand the triangular area | region between the crease | fold 2c and the crease | fold 2e.
　以下、本実施形態の角形二次電池１００の作用について説明する。 Hereinafter, the operation of the prismatic secondary battery 100 of the present embodiment will be described.
　本実施形態の角形二次電池１００は、前述のように、一端に開口１ａを有し、該開口１ａから電池容器１０の一部を露出させた状態で電池容器１０を覆う絶縁性の伸縮フィルム１と、該伸縮フィルム１の開口１ａから露出した電池容器１０を覆うとともに、該開口１ａの縁部１ｂを覆う絶縁性の粘着フィルム２と、を備えている。 As described above, the prismatic secondary battery 100 of the present embodiment has the opening 1a at one end, and the insulating stretchable film that covers the battery container 10 with a part of the battery container 10 exposed from the opening 1a. 1 and an insulating adhesive film 2 that covers the battery container 10 exposed from the opening 1a of the stretchable film 1 and covers the edge 1b of the opening 1a.
　これにより、例えば、角形二次電池１００の充放電による電極群４０の膨張収縮に伴って伸縮フィルム１が伸縮しても、伸縮フィルム１の開口１ａの縁部１ｂの剥がれが、その縁部１ｂを覆う粘着フィルム２によって防止される。したがって、実施形態の角形二次電池１００によれば、角形二次電池１００の電池容器１０を覆う絶縁性の伸縮フィルム１及び粘着フィルム２の剥がれを防止し、電池容器１０の外部環境に対する絶縁の信頼性を向上させることができる。 Thereby, for example, even if the stretchable film 1 expands / contracts due to the expansion / contraction of the electrode group 40 due to charging / discharging of the square secondary battery 100, the edge 1b of the opening 1a of the stretchable film 1 is peeled off. Is prevented by the adhesive film 2 covering the surface. Therefore, according to the prismatic secondary battery 100 of the embodiment, the insulating stretchable film 1 and the adhesive film 2 that cover the battery container 10 of the prismatic secondary battery 100 are prevented from peeling off, and the battery container 10 is insulated from the external environment. Reliability can be improved.
　また、本実施形態の角形二次電池１００において、伸縮フィルム１は、開口１ａから電池蓋１２の全体を露出させている。これにより、電池缶１１と電池蓋１２との間の溶接部を伸縮フィルム１によって覆う必要がなくなる。溶接部は、電池容器１０のその他の部分と比較して表面粗さや凹凸が大きくなる場合がある。したがって、伸縮フィルム１による溶接部の被覆を回避して、伸縮フィルム１と電池容器１０との密着性を向上させ、伸縮フィルム１の剥がれをより効果的に防止することができる。 In the rectangular secondary battery 100 of the present embodiment, the stretchable film 1 exposes the entire battery lid 12 from the opening 1a. This eliminates the need to cover the welded portion between the battery can 11 and the battery lid 12 with the stretchable film 1. The welded portion may have a larger surface roughness or unevenness than other portions of the battery case 10. Therefore, it is possible to avoid covering the welded portion with the stretchable film 1, improve the adhesion between the stretchable film 1 and the battery container 10, and more effectively prevent the stretchable film 1 from peeling off.
　また、伸縮フィルム１は、開口１ａから電池蓋１２の全体を露出させることで、伸縮フィルム１の開口１ａの縁部１ｂを電池缶１１の幅広側面１１ｃ及び幅狭側面１１ｄ上に配置し、伸縮フィルム１による電池容器１０の被覆を容易にすることができる。また、粘着フィルム２によって伸縮フィルム１の開口１ａの縁部１ｂを覆う面積を比較的大きくすることができ、伸縮フィルム１の剥がれをより効果的に防止することが可能になる。 In addition, the stretchable film 1 exposes the entire battery lid 12 from the opening 1a, so that the edge 1b of the opening 1a of the stretchable film 1 is disposed on the wide side surface 11c and the narrow side surface 11d of the battery can 11 to expand and contract. The battery container 10 can be easily covered with the film 1. Moreover, the area which covers the edge 1b of the opening 1a of the stretchable film 1 by the adhesive film 2 can be made relatively large, and it becomes possible to more effectively prevent the stretchable film 1 from peeling off.
　また、本実施形態の角形二次電池１００において、粘着フィルム２は、伸縮フィルム１の開口１ａから露出した電池蓋１２を覆うとともに、外部端子２０を露出させる貫通孔２ａを有している。これにより、粘着フィルム２によって、外部端子２０の溶接接合部２１に対するバスバーの接合を阻害することなく、伸縮フィルム１の開口１ａから露出した電池蓋１２を絶縁被覆することが可能になる。 Further, in the rectangular secondary battery 100 of the present embodiment, the adhesive film 2 has a through hole 2 a that covers the battery cover 12 exposed from the opening 1 a of the stretchable film 1 and exposes the external terminal 20. As a result, the adhesive film 2 can insulate the battery cover 12 exposed from the opening 1a of the stretchable film 1 without hindering the joining of the bus bar to the weld joint 21 of the external terminal 20.
　また、本実施形態の角形二次電池１００において、伸縮フィルム１は、開口１ａから一対の幅広側面１１ｃの一部である電池蓋１２側の上端部と、幅狭側面１１ｄの一部である電池蓋１２側の上端部と、を露出させている。そして、粘着フィルム２は、これら伸縮フィルム１の開口１ａから露出した幅広側面１１ｃの一部と幅狭側面１１ｄの一部を覆っている。換言すると、粘着フィルム２は、電池蓋１２と、それに隣接する電池缶１１の４面を覆っている。これにより、粘着フィルム２をより強固に電池容器１０及び伸縮フィルム１に貼り付けて、粘着フィルム２の剥がれを防止することができ、その結果、伸縮フィルム１の剥がれをより効果的に防止することができる。 Further, in the rectangular secondary battery 100 of the present embodiment, the stretchable film 1 includes a battery lid 12 side upper end portion that is a part of the pair of wide side surfaces 11c and a part of the narrow side surface 11d from the opening 1a. The upper end portion on the lid 12 side is exposed. The adhesive film 2 covers a part of the wide side surface 11c and a part of the narrow side surface 11d exposed from the opening 1a of the stretchable film 1. In other words, the adhesive film 2 covers the battery lid 12 and the four surfaces of the battery can 11 adjacent thereto. Thereby, the adhesive film 2 can be more firmly attached to the battery container 10 and the stretchable film 1 to prevent the adhesive film 2 from peeling off. As a result, the stretchable film 1 can be more effectively prevented from peeling off. Can do.
　また、本実施形態の角形二次電池１００において、粘着フィルム２は、ガス排出弁１３の少なくとも一部を露出させる貫通孔２ｂを有している。したがって、電池容器１０の内圧上昇時にガス排出弁１３が開放されたときに、ガス排出弁１３からのガスの排出が粘着フィルム２によって妨げられることが防止され、角形二次電池１００の安全性を確保することができる。 Further, in the rectangular secondary battery 100 of the present embodiment, the adhesive film 2 has a through hole 2b that exposes at least a part of the gas discharge valve 13. Therefore, when the gas discharge valve 13 is opened when the internal pressure of the battery container 10 is increased, the gas discharge from the gas discharge valve 13 is prevented from being hindered by the adhesive film 2, and the safety of the rectangular secondary battery 100 is improved. Can be secured.
　また、本実施形態の角形二次電池１００において、伸縮フィルム１は、熱可塑性を有する樹脂材料によって製作されている。これにより、前述のように、伸縮フィルム１を加熱して軟化させ、一方向から減圧吸引することで、電池容器１０を伸縮フィルム１によって容易かつ確実に隙間なく覆うことができる。したがって、角形二次電池１００の絶縁の信頼性の向上、生産性の向上、及び製造コストの低減が可能になる。 Moreover, in the square secondary battery 100 of the present embodiment, the stretchable film 1 is made of a resin material having thermoplasticity. Thereby, as described above, the stretchable film 1 is heated and softened, and the battery container 10 can be easily and reliably covered with the stretchable film 1 without any gaps by sucking under reduced pressure from one direction. Therefore, it is possible to improve the insulation reliability of the rectangular secondary battery 100, improve the productivity, and reduce the manufacturing cost.
　また、本実施形態の角形二次電池１００において、粘着フィルム２の引張強さが伸縮フィルム１の引張強さよりも強い。これにより、粘着フィルム２と伸縮フィルム１の開口１ａの縁部１ｂとの間に引張応力が作用した場合でも、粘着フィルム２によって伸縮フィルム１の開口１ａの縁部１ｂを強固に保持し、伸縮フィルム１の剥がれをより効果的に防止することができる。 Further, in the rectangular secondary battery 100 of the present embodiment, the tensile strength of the adhesive film 2 is stronger than the tensile strength of the stretchable film 1. Thereby, even when a tensile stress acts between the adhesive film 2 and the edge 1b of the opening 1a of the stretchable film 1, the edge 1b of the opening 1a of the stretchable film 1 is firmly held by the adhesive film 2 and stretched. The peeling of the film 1 can be prevented more effectively.
　また、本実施形態の角形二次電池１００において、粘着フィルム２は、基材層２αと粘着層２βとを有し、粘着層２βと伸縮フィルム１との間の粘着力は、伸縮フィルム１と電池容器１０との間の接着力よりも強く、粘着フィルム２の粘着層２βと基材層２αとの間の粘着力よりも弱い。換言すると、粘着層２βと基材層２αとの間の保持力は、粘着層２βと伸縮フィルム１との間の保持力より大きい。また、粘着層２βと基材層２αとの間の保持力は、伸縮フィルム１と電池容器１０との間の保持力より大きい。これにより、粘着フィルム２は、基材層２αに保持された粘着層２βによって、伸縮フィルム１を強固に保持するとともに、伸縮フィルム１よりも電池容器１０に強固に固定されて、伸縮フィルム１の剥がれをより効果的に防止することができる。 Moreover, in the square secondary battery 100 of this embodiment, the adhesive film 2 has the base material layer 2α and the adhesive layer 2β, and the adhesive force between the adhesive layer 2β and the stretchable film 1 is the same as that of the stretchable film 1. It is stronger than the adhesive force between the battery container 10 and weaker than the adhesive force between the adhesive layer 2β of the adhesive film 2 and the base material layer 2α. In other words, the holding force between the adhesive layer 2β and the base material layer 2α is larger than the holding force between the adhesive layer 2β and the stretchable film 1. Further, the holding force between the adhesive layer 2β and the base material layer 2α is larger than the holding force between the stretchable film 1 and the battery container 10. Thereby, the adhesive film 2 firmly holds the stretchable film 1 by the adhesive layer 2β held by the base material layer 2α, and is more firmly fixed to the battery container 10 than the stretchable film 1, so that the stretchable film 1 Peeling can be prevented more effectively.
　また、本実施形態の角形二次電池１００において、粘着フィルム２の粘着層２βと基材層２αとの間の粘着力は、粘着層２βと電池容器１０との間の粘着力よりも強い。これにより、粘着フィルム２の貼り直しが可能になり、角形二次電池１００の製造工程における粘着フィルム２の歩留まりを向上させ、製造コストを低減することが可能になる。また、例えば、角形二次電池１００のリサイクル時に粘着フィルム２の回収が容易になる。 Further, in the rectangular secondary battery 100 of the present embodiment, the adhesive force between the adhesive layer 2β and the base material layer 2α of the adhesive film 2 is stronger than the adhesive force between the adhesive layer 2β and the battery container 10. Thereby, the adhesive film 2 can be reattached, the yield of the adhesive film 2 in the manufacturing process of the square secondary battery 100 can be improved, and the manufacturing cost can be reduced. In addition, for example, the adhesive film 2 can be easily collected when the rectangular secondary battery 100 is recycled.
　また、本実施形態の角形二次電池１００において、粘着フィルム２が着色されている場合には、レーザ変位計等の非接触式の測定器によって角形二次電池１００の外形寸法を測定する際に、粘着フィルム２の表面位置を正確に計測できる。したがって、角形二次電池１００の外形寸法の測定精度を向上させることができる。さらに、角形二次電池１００の仕様や納品先によって異なる色に着色することで、角形二次電池１００の仕様や納品先の判別を容易にすることができる。また、正極外部端子２０Ａ側と負極外部端子２０Ｂ側とで粘着フィルム２を異なる色に着色すれば、角形二次電池１００の正極と負極の判別が容易になる。 Moreover, in the square secondary battery 100 of this embodiment, when the adhesive film 2 is colored, when measuring the external dimensions of the square secondary battery 100 with a non-contact type measuring instrument such as a laser displacement meter. The surface position of the adhesive film 2 can be accurately measured. Therefore, the measurement accuracy of the external dimensions of the prismatic secondary battery 100 can be improved. Furthermore, by coloring in different colors depending on the specifications of the prismatic secondary battery 100 and the delivery destination, it is possible to easily identify the specifications of the prismatic secondary battery 100 and the delivery destination. Further, if the adhesive film 2 is colored in different colors on the positive electrode external terminal 20A side and the negative electrode external terminal 20B side, the positive electrode and the negative electrode of the prismatic secondary battery 100 can be easily distinguished.
　以上説明したように、本実施形態の角形二次電池１００によれば、電池容器１０を覆う絶縁材料である伸縮フィルム１及び粘着フィルム２の剥がれを防止し、電池容器１０の外部環境に対する絶縁の信頼性を向上させることができる。 As described above, according to the rectangular secondary battery 100 of the present embodiment, the stretchable film 1 and the adhesive film 2 that are insulating materials covering the battery container 10 are prevented from being peeled, and the battery container 10 is insulated from the external environment. Reliability can be improved.
　なお、前述の実施形態では、角形二次電池１００の絶縁被覆工程において、熱可塑性の樹脂材料からなる伸縮フィルム１を電池缶１１の底面１１ｂ側に配置し、加熱により軟化させた伸縮フィルム１を電池蓋１２側から減圧吸引する例について説明した。しかし、角形二次電池１００の絶縁被覆工程は、前述の例に限定されない。以下、角形二次電池１００の絶縁被覆工程の変形例１及び２について説明する。 In the above-described embodiment, in the insulating coating process of the rectangular secondary battery 100, the stretch film 1 made of a thermoplastic resin material is disposed on the bottom surface 11b side of the battery can 11, and the stretch film 1 softened by heating is used. An example in which vacuum suction is performed from the battery lid 12 side has been described. However, the insulating coating process of the prismatic secondary battery 100 is not limited to the above example. Hereinafter, modifications 1 and 2 of the insulating coating process of the prismatic secondary battery 100 will be described.
（角形二次電池の絶縁被覆工程：変形例１）
　図６Ａ及び図６Ｂは、図１Ａに示す角形二次電池１００の絶縁被覆工程の変形例１を説明する斜視図である。図６Ｃは、図６ＢのＣ－Ｃ線に沿う拡大断面図である。なお、図６Ｃにおいて、電池缶１１内の構成の図示は省略している。 (Insulation coating process for prismatic secondary battery: Modification 1)
6A and 6B are perspective views for explaining a first modification of the insulating coating process of the prismatic secondary battery 100 shown in FIG. 1A. 6C is an enlarged cross-sectional view taken along the line CC of FIG. 6B. In FIG. 6C, the illustration of the configuration inside the battery can 11 is omitted.
　本変形例では、まず、図６Ａに示すように、絶縁被覆前の角形二次電池１００と、角形二次電池１００の電池容器１０を覆うための伸縮フィルム１を用意する。そして、電池容器１０を構成する電池蓋１２側に、伸縮フィルム１を配置する。ここで、伸縮フィルム１は、前述の実施形態と同様に、熱可塑性を有する樹脂材料によって製作されている。そのため、例えば、ヒーター等によって伸縮フィルム１を加熱して軟化させた後、吸引装置等によって電池缶１１の底面１１ｂ側から空気を吸引することで、軟化した伸縮フィルム１を電池容器１０に密着させて電池蓋１２側から包み込むことができる。 In this modification, first, as shown in FIG. 6A, a rectangular secondary battery 100 before insulation coating and a stretchable film 1 for covering the battery container 10 of the rectangular secondary battery 100 are prepared. And the elastic film 1 is arrange | positioned at the battery lid 12 side which comprises the battery container 10. FIG. Here, the stretchable film 1 is made of a resin material having thermoplasticity as in the above-described embodiment. Therefore, for example, the elastic film 1 is heated and softened with a heater or the like, and then the softened elastic film 1 is brought into close contact with the battery container 10 by sucking air from the bottom surface 11b side of the battery can 11 with a suction device or the like. Can be wrapped from the battery lid 12 side.
　このとき、伸縮フィルム１の電池缶１１の底面１１ｂ側の端部は、図６Ｃに示すように、電池缶１１の底面１１ｂ上で重なることで互いに溶着され、電池缶１１の底面１１ｂ上に熱溶着部１ｃが形成されて封止される。その後、例えば、伸縮フィルム１から電池蓋１２と電池缶１１との間の溶接部を露出させるように、電池缶１１の上端で伸縮フィルム１を切断することで、電池容器１０の電池蓋１２側に伸縮フィルム１の開口１ａが形成される。その後、前述の実施形態と同様に、粘着フィルム２によって開口１ａから露出した電池蓋１２を覆う。本変形例の絶縁被覆工程によれば、電池容器１０を電池蓋１２側から伸縮フィルム１によって覆うことができる。 At this time, the end of the stretchable film 1 on the bottom surface 11b side of the battery can 11 is welded together by overlapping on the bottom surface 11b of the battery can 11 as shown in FIG. A weld 1c is formed and sealed. Thereafter, for example, by cutting the stretchable film 1 at the upper end of the battery can 11 so that the welded portion between the battery lid 12 and the battery can 11 is exposed from the stretchable film 1, the battery lid 12 side of the battery container 10. The opening 1a of the stretchable film 1 is formed on the surface. Thereafter, the battery lid 12 exposed from the opening 1a is covered with the adhesive film 2 in the same manner as in the above-described embodiment. According to the insulating coating process of this modification, the battery container 10 can be covered with the stretchable film 1 from the battery lid 12 side.
（角形二次電池の絶縁被覆工程：変形例２）
　図７Ａから図７Ｅは、図１Ａに示す角形二次電池１００の絶縁被覆工程の変形例２を説明する斜視図である。 (Insulation coating process for prismatic secondary battery: Modification 2)
7A to 7E are perspective views for explaining a second modification of the insulating coating process of the prismatic secondary battery 100 shown in FIG. 1A.
　本変形例では、前述の実施形態１の絶縁被覆工程と同様に、まず、図７Ａに示すように、絶縁被覆前の角形二次電池１００と、角形二次電池１００の電池容器１０を覆うための伸縮フィルム１を用意する。ただし、本変形例で用いる伸縮フィルム１は、前述のＰＥＴ、ＰＰ等、熱収縮性を有する樹脂材料によって製作されている。伸縮フィルム１は、電池容器１０の厚さ方向における両端部が電池蓋１２側に向けて引き上げられることで、電池容器１０を挟んで二つ折りにされる。その後、伸縮フィルム１は、電池容器１０の幅方向の両端部が電池缶１１の幅狭側面１１ｄに沿って熱溶着されて熱溶着部１ｄが形成され、電池蓋１２側に開口を有する袋状になる。 In the present modification, as in the insulating coating process of the first embodiment, first, as shown in FIG. 7A, the rectangular secondary battery 100 before the insulating coating and the battery container 10 of the rectangular secondary battery 100 are covered. A stretchable film 1 is prepared. However, the stretchable film 1 used in the present modification is made of a heat-shrinkable resin material such as the aforementioned PET or PP. The stretchable film 1 is folded in half with the battery container 10 sandwiched by lifting both ends of the battery container 10 in the thickness direction toward the battery lid 12 side. Thereafter, the stretchable film 1 is formed in a bag shape in which both end portions in the width direction of the battery container 10 are heat-welded along the narrow side surface 11d of the battery can 11 to form a heat-welded portion 1d, and an opening is formed on the battery lid 12 side. become.
　次に、図７Ｃに示すように、袋状に形成された伸縮フィルム１の開口を熱溶着して熱溶着部１ｄを形成し、伸縮フィルム１によって外部端子２０を含めて電池容器１０の全体を覆う。次に、図７Ｄに示すように、電池容器１０の全体を覆う伸縮フィルム１を加熱して収縮させ、伸縮フィルム１を電池容器１０に密着させる。次に、図７Ｅに示すように、例えば、電池蓋１２と電池缶１１との間の溶接部よりも電池缶１１の底面１１ｂ側の位置で伸縮フィルム１を切断して開口１ａを形成する。その後、前述の実施形態と同様に、粘着フィルム２によって開口１ａから露出した電池蓋１２を覆う。本変形例の絶縁被覆工程によれば、減圧吸引によらず、電池容器１０を伸縮フィルム１によって覆うことができる。 Next, as shown in FIG. 7C, the opening of the stretchable film 1 formed in a bag shape is thermally welded to form a heat welded portion 1d, and the entire battery container 10 including the external terminals 20 is stretched by the stretchable film 1. cover. Next, as shown in FIG. 7D, the stretchable film 1 covering the entire battery container 10 is heated and shrunk, and the stretchable film 1 is brought into close contact with the battery container 10. Next, as shown in FIG. 7E, for example, the stretchable film 1 is cut at a position closer to the bottom surface 11b side of the battery can 11 than the welded portion between the battery lid 12 and the battery can 11 to form the opening 1a. Thereafter, the battery lid 12 exposed from the opening 1a is covered with the adhesive film 2 in the same manner as in the above-described embodiment. According to the insulating coating process of the present modification, the battery container 10 can be covered with the stretchable film 1 regardless of vacuum suction.
　なお、本変形例において、伸縮フィルム１の熱溶着部１ｄの位置は、特に限定されない。また、伸縮フィルム１の開口１ａは、少なくとも外部端子２０の溶接接合部２１の上面を露出させるように形成すればよい。 In addition, in this modification, the position of the heat welding part 1d of the elastic film 1 is not specifically limited. Moreover, what is necessary is just to form the opening 1a of the elastic film 1 so that the upper surface of the welding junction part 21 of the external terminal 20 may be exposed at least.
（実施形態２）
　次に、本発明の角形二次電池の実施形態２について、図２から図４を援用し、図８Ａ及び図８Ｂを用いて説明する。図８Ａは、本発明の実施形態２に係る角形二次電池１００Ａを示す外観斜視図である。図８Ｂは、図８Ａに示す角形二次電池１００Ａから粘着フィルム２を取り外した状態を示す分解斜視図である。 (Embodiment 2)
Next, Embodiment 2 of the rectangular secondary battery of the present invention will be described with reference to FIGS. 8A and 8B with reference to FIGS. FIG. 8A is an external perspective view showing a prismatic secondary battery 100A according to Embodiment 2 of the present invention. FIG. 8B is an exploded perspective view showing a state where the adhesive film 2 is removed from the rectangular secondary battery 100A shown in FIG. 8A.
　本実施形態の角形二次電池１００Ａは、電池容器１０を覆う伸縮フィルム１Ａの開口１ａの大きさ、及び、電池容器１０を覆う粘着フィルム２Ａの大きさが、前述の実施形態１で説明した角形二次電池１００と異なっている。本実施形態の角形二次電池１００Ａのその他の点は、実施形態１の角形二次電池１００と同一であるので、同一の部分には同一の符号を付して説明を省略する。また、本実施形態の伸縮フィルム１Ａを電池容器１０に密着させる絶縁被覆工程は、例えば、前述の実施形態１の絶縁被覆工程とその変形例１及び２のいずれかを採用することができる。 In the rectangular secondary battery 100A of the present embodiment, the size of the opening 1a of the stretchable film 1A that covers the battery container 10 and the size of the adhesive film 2A that covers the battery container 10 are the square shapes described in the first embodiment. Different from the secondary battery 100. The other points of the prismatic secondary battery 100A of the present embodiment are the same as those of the prismatic secondary battery 100 of Embodiment 1, and therefore, the same portions are denoted by the same reference numerals and description thereof is omitted. In addition, as the insulating coating process for closely attaching the stretchable film 1A of the present embodiment to the battery container 10, for example, the insulating coating process of the first embodiment described above and any one of the modifications 1 and 2 can be employed.
　本実施形態の角形二次電池１００Ａは、電池容器１０の幅Ｗ方向における伸縮フィルム１Ａの開口１ａの寸法が、電池蓋１２の長手方向の寸法、すなわち、電池容器１０の幅Ｗよりも小さくなっている。また、電池蓋１２及び電池缶１１の幅広側面１１ｃに沿う伸縮フィルム１Ａの開口１ａの寸法が、電池容器１０の厚さＴよりも大きくなっている。これにより、伸縮フィルム１Ａは、電池容器１０の幅Ｗ方向の両端部において、電池容器１０の５面、すなわち、電池缶１１の底面１１ｂ、一対の幅広側面１１ｃ、及び幅狭側面１１ｄ、並びに、電池蓋１２を覆っている。 In the rectangular secondary battery 100 </ b> A of the present embodiment, the size of the opening 1 a of the stretchable film 1 </ b> A in the width W direction of the battery container 10 is smaller than the size in the longitudinal direction of the battery lid 12, that is, the width W of the battery container 10. ing. Further, the size of the opening 1 a of the stretchable film 1 </ b> A along the wide side surface 11 c of the battery lid 12 and the battery can 11 is larger than the thickness T of the battery container 10. Thereby, the stretchable film 1A has five surfaces of the battery container 10, that is, the bottom surface 11b of the battery can 11, the pair of wide side surfaces 11c, the narrow side surface 11d, and both ends of the battery container 10 in the width W direction. The battery cover 12 is covered.
　また、伸縮フィルム１Ａは、電池容器１０の幅Ｗ方向の両端部を除く中間部において、開口１ａから電池蓋１２と電池缶１１の幅広側面１１ｃの上端部を露出させている。換言すると、伸縮フィルム１Ａは、電池容器１０の幅Ｗ方向の両端部を除く中間部において、電池容器１０の３面、すなわち、電池缶１１の底面１１ｂと、一対の幅広側面１１ｃの上端部を除く部分とを覆っている。要するに、伸縮フィルム１Ａは、開口１ａから電池蓋１２の一部と電池缶１１の一対の幅広側面１１ｃの一部を露出させ、電池蓋１２の長手方向の両端部と幅狭側面１１ｄを露出させることなく覆っている。 Further, in the stretchable film 1A, the upper end portions of the battery lid 12 and the wide side surface 11c of the battery can 11 are exposed from the opening 1a in the middle portion excluding both end portions in the width W direction of the battery case 10. In other words, the stretchable film 1A has three surfaces of the battery container 10, that is, the bottom surface 11b of the battery can 11 and the upper ends of the pair of wide side surfaces 11c at the intermediate portion excluding both ends in the width W direction of the battery container 10. It covers the part to be removed. In short, the stretchable film 1A exposes a part of the battery lid 12 and a part of the pair of wide side surfaces 11c of the battery can 11 from the opening 1a, and exposes both ends in the longitudinal direction of the battery lid 12 and the narrow side surface 11d. Covering without.
　また、本実施形態において、粘着フィルム２Ａは、長手方向の寸法Ｄ２が電池容器１０の幅Ｗよりも小さくなっている。そのため、粘着フィルム２Ａは、伸縮フィルム１Ａの開口１ａから露出した電池蓋１２の長手方向の中間部、電池缶１１の幅広側面１１ｃの上端部、及び、伸縮フィルム１Ａの開口１ａの縁部１ｂを覆っているが、一対の幅狭側面１１ｄは覆っていない。換言すると、粘着フィルム２Ａは、電池容器１０の３面、すなわち、電池蓋１２及び電池缶１１の一対の幅広側面１１ｃを覆っている。 In the present embodiment, the adhesive film 2A has a dimension D2 in the longitudinal direction smaller than the width W of the battery container 10. Therefore, the adhesive film 2A has an intermediate portion in the longitudinal direction of the battery lid 12 exposed from the opening 1a of the stretchable film 1A, an upper end portion of the wide side surface 11c of the battery can 11, and an edge 1b of the opening 1a of the stretchable film 1A. Although covered, the pair of narrow side surfaces 11d are not covered. In other words, the adhesive film 2 </ b> A covers three surfaces of the battery container 10, that is, the pair of wide side surfaces 11 c of the battery lid 12 and the battery can 11.
　本実施形態の角形二次電池１００Ａによれば、実施形態１の角形二次電池１００と同様の効果が得られるだけでなく、図５Ｂに示す実施形態１の角形二次電池１００と比較して、粘着フィルム２Ａを折目２ｅ，２ｃで折り畳んで重ねる工程を省略することができる。
したがって、角形二次電池１００Ａの製造を容易にして、生産性を向上させることができる。また、電池缶１１の幅広側面１１ｃ上で粘着フィルム２Ａが折り重なることがないので、実施形態１の角形二次電池１００と比較して、角形二次電池１００Ａを厚さＴ方向に並べて構成する組電池の体積をより減少させることができる。 According to the prismatic secondary battery 100A of the present embodiment, not only the same effects as those of the prismatic secondary battery 100 of Embodiment 1 are obtained, but also compared with the prismatic secondary battery 100 of Embodiment 1 shown in FIG. 5B. The step of folding the adhesive film 2A at the folds 2e and 2c and stacking them can be omitted.
Therefore, the manufacturing of the rectangular secondary battery 100A can be facilitated and the productivity can be improved. In addition, since the adhesive film 2A does not fold over the wide side surface 11c of the battery can 11, as compared with the prismatic secondary battery 100 of the first embodiment, a set in which the prismatic secondary batteries 100A are arranged in the thickness T direction. The volume of the battery can be further reduced.
（実施形態３）
　次に、本発明の角形二次電池の実施形態３について、図２から図４を援用し、図９Ａ及び図９Ｂを用いて説明する。図９Ａは、本発明の実施形態３に係る角形二次電池１００Ｂを示す外観斜視図である。図９Ｂは、図９Ａに示す角形二次電池１００Ｂから粘着フィルム２Ｂを取り外した分解斜視図である。 (Embodiment 3)
Next, Embodiment 3 of the rectangular secondary battery of the present invention will be described with reference to FIGS. 9A and 9B with reference to FIGS. FIG. 9A is an external perspective view showing a prismatic secondary battery 100B according to Embodiment 3 of the present invention. FIG. 9B is an exploded perspective view in which the adhesive film 2B is removed from the rectangular secondary battery 100B shown in FIG. 9A.
　本実施形態の角形二次電池１００Ｂは、電池容器１０を覆う伸縮フィルム１Ｂの開口１ａの大きさ、及び、電池容器１０を覆う粘着フィルム２Ｂの大きさが、前述の実施形態１及び２で説明した角形二次電池１００，１００Ａと異なっている。本実施形態の角形二次電池１００Ｂのその他の点は、実施形態１の角形二次電池１００と同一であるので、同一の部分には同一の符号を付して説明を省略する。また、本実施形態の伸縮フィルム１Ｂを電池容器１０に密着させる絶縁被覆工程は、例えば、前述の実施形態１の絶縁被覆工程とその変形例１及び２のいずれかを採用することができる。 In the square secondary battery 100B of the present embodiment, the size of the opening 1a of the stretchable film 1B covering the battery container 10 and the size of the adhesive film 2B covering the battery container 10 are described in the above-described first and second embodiments. This is different from the rectangular secondary batteries 100 and 100A. The other points of the prismatic secondary battery 100B of the present embodiment are the same as those of the prismatic secondary battery 100 of Embodiment 1, and therefore the same parts are denoted by the same reference numerals and description thereof is omitted. In addition, as the insulating coating process for closely attaching the stretchable film 1B of the present embodiment to the battery container 10, for example, the insulating coating process of the first embodiment described above and any one of the modifications 1 and 2 can be employed.
　本実施形態の角形二次電池１００Ｂは、電池容器１０の幅Ｗ方向における伸縮フィルム１Ｂの開口１ａの寸法が、電池蓋１２の長手方向の寸法、すなわち、電池容器１０の幅Ｗよりも小さくなっている。また、電池容器１０の厚さＴ方向における伸縮フィルム１Ｂの開口１ａの寸法が、電池容器１０の厚さＴよりも小さくなっている。これにより、伸縮フィルム１Ｂは、電池缶１１の全体を覆って、開口１ａから電池蓋１２の一部、すなわち電池蓋１２の周縁部を除く部分を露出させている。 In the rectangular secondary battery 100 </ b> B of the present embodiment, the size of the opening 1 a of the stretchable film 1 </ b> B in the width W direction of the battery container 10 is smaller than the size in the longitudinal direction of the battery lid 12, that is, the width W of the battery container 10. ing. Further, the dimension of the opening 1 a of the stretchable film 1 </ b> B in the thickness T direction of the battery container 10 is smaller than the thickness T of the battery container 10. Thereby, the stretchable film 1 </ b> B covers the entire battery can 11 and exposes a part of the battery lid 12, that is, a portion excluding the peripheral edge of the battery lid 12 from the opening 1 a.
　また、本実施形態において、粘着フィルム２Ｂは、伸縮フィルム１Ｂの開口１ａから露出した電池蓋１２の周縁部を除く部分と伸縮フィルム１Ｂの開口１ａの縁部１ｂを覆っている。換言すると、粘着フィルム２Ｂは、電池容器１０の１面、すなわち、電池蓋１２の上面のみを覆っている。本実施形態の角形二次電池１００Ｂによれば、実施形態１の角形二次電池１００と同様の効果を得られるだけでなく、電池缶１１の幅広側面１１ｃにおいて伸縮フィルム１Ｂと粘着フィルム２Ｂとが重ならないので、実施形態２の角形二次電池１００Ａと比較して、角形二次電池１００Ｂを厚さＴ方向に並べて構成する組電池の体積をより減少させることができる。 In the present embodiment, the adhesive film 2B covers the portion excluding the peripheral portion of the battery lid 12 exposed from the opening 1a of the stretchable film 1B and the edge 1b of the opening 1a of the stretchable film 1B. In other words, the adhesive film 2 </ b> B covers only one surface of the battery container 10, i.e., the upper surface of the battery lid 12. According to the prismatic secondary battery 100B of the present embodiment, not only can the same effect as that of the prismatic secondary battery 100 of the first embodiment be obtained, but the stretchable film 1B and the adhesive film 2B are formed on the wide side surface 11c of the battery can 11. Since they do not overlap, the volume of the assembled battery in which the prismatic secondary batteries 100B are arranged in the thickness T direction can be further reduced as compared with the prismatic secondary battery 100A of the second embodiment.
（実施形態４）
　次に、本発明の角形二次電池の実施形態４について、図２から図４を援用し、図１０を用いて説明する。図１０は、本発明の実施形態４に係る角形二次電池１００Ｃを示す外観斜視図である。 (Embodiment 4)
Next, Embodiment 4 of the prismatic secondary battery of the present invention will be described with reference to FIGS. 2 to 4 and FIG. FIG. 10 is an external perspective view showing a prismatic secondary battery 100C according to Embodiment 4 of the present invention.
　本実施形態の角形二次電池１００Ｃは、電池容器１０を覆う粘着フィルム２Ｃの外部端子２０を露出させる貫通孔２ａの大きさが、前述の実施形態１で説明した角形二次電池１００の粘着フィルム２の貫通孔２ａよりも小さくなっている。本実施形態の角形二次電池１００Ｃのその他の点は、実施形態１の角形二次電池１００と同一であるので、同一の部分には同一の符号を付して説明を省略する。 In the rectangular secondary battery 100C of the present embodiment, the size of the through hole 2a that exposes the external terminal 20 of the adhesive film 2C that covers the battery container 10 is the same as that of the rectangular secondary battery 100 described in the first embodiment. It is smaller than the two through holes 2a. The other points of the rectangular secondary battery 100C of the present embodiment are the same as those of the rectangular secondary battery 100 of the first embodiment, and therefore the same portions are denoted by the same reference numerals and description thereof is omitted.
　本実施形態において、粘着フィルム２Ｃの貫通孔２ａは、外部端子２０の溶接接合部２１を露出させ、かつ、溶接接合部２１と電池蓋１２との間のガスケット３の外形寸法と等しいかそれよりも僅かに小さくなっている。これにより、粘着フィルム２Ｃは、粘着層２βがガスケット３と密着し、ガスケット３の少なくとも一部を覆う。本実施形態において、粘着フィルム２Ｃは、ガスケット３の下端部を覆っているが、ガスケット３の全体を覆うようにしてもよい。 In the present embodiment, the through-hole 2a of the adhesive film 2C exposes the weld joint 21 of the external terminal 20 and is equal to or larger than the outer dimension of the gasket 3 between the weld joint 21 and the battery lid 12. Is slightly smaller. Thus, in the adhesive film 2C, the adhesive layer 2β is in close contact with the gasket 3 and covers at least a part of the gasket 3. In the present embodiment, the adhesive film 2 </ b> C covers the lower end portion of the gasket 3, but may cover the entire gasket 3.
　このように、粘着フィルム２Ｃをガスケット３に密着させてガスケット３の少なくとも一部を覆うようにするためには、例えば、粘着フィルム２Ｃを前述の熱収縮性を有する樹脂材料によって製作する。そして、粘着フィルム２Ｃに溶接接合部２１及びガスケット３の外形寸法よりも僅かに大きい貫通孔２ａを形成し、貫通孔２ａから溶接接合部２１及びガスケット３を露出させた状態で、粘着フィルム２Ｃを加熱して収縮させる。これにより、貫通孔２ａが収縮し、粘着フィルム２Ｃをガスケット３に密着させてガスケット３を覆うことができる。 In this way, in order to adhere the adhesive film 2C to the gasket 3 so as to cover at least a part of the gasket 3, for example, the adhesive film 2C is manufactured using the above-described resin material having heat shrinkability. And the adhesive film 2C is formed in a state where the through-hole 2a slightly larger than the outer dimensions of the weld joint 21 and the gasket 3 is formed in the adhesive film 2C, and the weld joint 21 and the gasket 3 are exposed from the through-hole 2a. Heat to shrink. Thereby, the through-hole 2a shrink | contracts, the adhesive film 2C can be stuck to the gasket 3, and the gasket 3 can be covered.
　なお、粘着フィルム２Ｃを熱収縮させない場合には、粘着フィルム２Ｃの伸縮性を利用して粘着フィルム２Ｃをガスケット３に密着させてもよい。具体的には、粘着フィルム２Ｃの貫通孔２ａをガスケット３の外形寸法よりも僅かに小さく形成し、ガスケット３を貫通孔２ａに押し込んで貫通孔２ａを拡張させることで、粘着フィルム２Ｃをガスケット３に密着させてガスケット３を覆うようにしてもよい。 In addition, when the adhesive film 2C is not thermally contracted, the adhesive film 2C may be adhered to the gasket 3 by using the stretchability of the adhesive film 2C. Specifically, the adhesive film 2C is formed to be slightly smaller than the outer dimension of the gasket 3, and the gasket 3 is pushed into the through-hole 2a to expand the through-hole 2a. The gasket 3 may be covered by being in close contact therewith.
　本実施形態の角形二次電池１００Ｃによれば、粘着フィルム２Ｃがガスケット３に密着してガスケット３を覆うことで、電池蓋１２が粘着フィルム２Ｃの貫通孔２ａから露出することがなく、外部端子２０の近傍における電池容器１０の絶縁性が向上する。 According to the rectangular secondary battery 100C of the present embodiment, the adhesive film 2C is in close contact with the gasket 3 to cover the gasket 3, so that the battery lid 12 is not exposed from the through hole 2a of the adhesive film 2C. The insulation property of the battery container 10 in the vicinity of 20 is improved.
　以上、図面を用いて本発明の実施の形態を詳述してきたが、具体的な構成はこの実施形態に限定されるものではなく、本発明の要旨を逸脱しない範囲における設計変更等があっても、それらは本発明に含まれるものである。 The embodiment of the present invention has been described in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.
１，１Ａ，１Ｂ　伸縮フィルム、１ａ　開口、１ｂ　縁部、２，２Ａ，２Ｂ，２Ｃ　粘着フィルム、２ａ　貫通孔、２ｂ　貫通孔、２α　基材層、２β　粘着層、３　ガスケット、１０　電池容器、１１　電池缶、１１ｃ　幅広側面、１１ｄ　幅狭側面、１２　電池蓋、１３　ガス排出弁、２０　外部端子、２０Ａ　正極外部端子、２０Ｂ　負極外部端子、４０　電極群、１００，１００Ａ，１００Ｂ，１００Ｃ　角形二次電池 1, 1A, 1B stretchable film, 1a opening, 1b edge, 2, 2A, 2B, 2C adhesive film, 2a through hole, 2b through hole, 2α substrate layer, 2β adhesive layer, 3 gasket, 10 battery container, 11 Battery can, 11c Wide side, 11d Narrow side, 12 Battery lid, 13 Gas exhaust valve, 20 External terminal, 20A Positive external terminal, 20B Negative external terminal, 40 Electrode group, 100, 100A, 100B, 100C Rectangular secondary battery

Claims (14)

  1. 　角形の電池容器を備えた角形二次電池であって、
    　一端に開口を有し該開口から前記電池容器の一部を露出させた状態で前記電池容器を覆う絶縁性の伸縮フィルムと、該伸縮フィルムの前記開口から露出した前記電池容器を覆うとともに該開口の縁部を覆う絶縁性の粘着フィルムと、を備えることを特徴とする角形二次電池。     A prismatic secondary battery having a prismatic battery container,
    An insulating stretch film covering the battery container with an opening at one end and a part of the battery container exposed from the opening; and covering the battery container exposed from the opening of the stretch film and the opening An insulative adhesive film covering the edge of the prismatic secondary battery.
  2. 　前記電池容器は、電極群を収容する一端が開放された電池缶と、正極及び負極外部端子が設けられ前記電池缶を封止する電池蓋と、を有し、
    　前記伸縮フィルムは、前記開口から前記電池蓋の少なくとも一部を露出させ、
    　前記粘着フィルムは、前記開口から露出した前記電池蓋を覆うとともに前記正極及び負極外部端子を露出させる貫通孔を有することを特徴とする請求項１に記載の角形二次電池。     The battery container has a battery can opened at one end for accommodating an electrode group, and a battery lid provided with a positive electrode and a negative electrode external terminal to seal the battery can,
    The stretchable film exposes at least a part of the battery lid from the opening,
    2. The prismatic secondary battery according to claim 1, wherein the adhesive film has a through hole that covers the battery cover exposed from the opening and exposes the positive electrode and the negative electrode external terminal.
  3. 　前記電池缶は、一対の幅広側面と一対の幅狭側面とを有する扁平な形状を有し、
    　前記伸縮フィルムは、前記開口から前記一対の幅広側面の一部を露出させ、
    　前記粘着フィルムは、前記幅広側面の前記一部を覆うことを特徴とする請求項２に記載の角形二次電池。     The battery can has a flat shape having a pair of wide side surfaces and a pair of narrow side surfaces,
    The stretchable film exposes part of the pair of wide side surfaces from the opening,
    The prismatic secondary battery according to claim 2, wherein the adhesive film covers the part of the wide side surface.
  4. 　前記伸縮フィルムは、前記開口から前記一対の幅狭側面の一部を露出させ、
    　前記粘着フィルムは、前記幅狭側面の前記一部を覆うことを特徴とする請求項３に記載の角形二次電池。     The stretchable film exposes part of the pair of narrow side surfaces from the opening,
    The prismatic secondary battery according to claim 3, wherein the adhesive film covers the part of the narrow side surface.
  5. 　前記伸縮フィルムは、前記電池缶の全体を覆って前記開口から前記電池蓋の一部を露出させ、
    　前記粘着フィルムは、前記電池蓋の前記一部を覆うことを特徴とする請求項２に記載の角形二次電池。     The stretch film covers the entire battery can and exposes a part of the battery lid from the opening,
    The prismatic secondary battery according to claim 2, wherein the adhesive film covers the part of the battery lid.
  6. 　前記電池蓋と前記正極及び負極外部端子との間にガスケットを備え、
    　前記粘着フィルムは、前記ガスケットを覆うことを特徴とする請求項２から請求項５のいずれか一項に記載の角形二次電池。     A gasket is provided between the battery lid and the positive and negative external terminals,
    The prismatic secondary battery according to any one of claims 2 to 5, wherein the adhesive film covers the gasket.
  7. 　前記電池蓋は、前記電池容器の内圧上昇時に開放されるガス排出弁を有し、
    　前記粘着フィルムは、前記ガス排出弁の少なくとも一部を露出させる貫通孔を有することを特徴とする請求項２から請求項５のいずれか一項に記載の角形二次電池。     The battery lid has a gas discharge valve that is opened when the internal pressure of the battery container is increased,
    The prismatic secondary battery according to any one of claims 2 to 5, wherein the adhesive film has a through hole that exposes at least a part of the gas discharge valve.
  8. 　前記伸縮フィルムは、熱可塑性を有する樹脂材料によって製作されていることを特徴とする請求項１に記載の角形二次電池。 2. The prismatic secondary battery according to claim 1, wherein the stretchable film is made of a resin material having thermoplasticity.
  9. 　前記伸縮フィルムは、熱収縮性を有する樹脂材料によって製作されていることを特徴とする請求項８に記載の角形二次電池。 The prismatic secondary battery according to claim 8, wherein the stretchable film is made of a heat-shrinkable resin material.
  10. 　前記粘着フィルムの引張強さが前記伸縮フィルムの引張強さよりも強いことを特徴とする請求項１に記載の角形二次電池。 The prismatic secondary battery according to claim 1, wherein the tensile strength of the adhesive film is stronger than the tensile strength of the stretchable film.
  11. 　前記粘着フィルムは、基材層と粘着層とを有し、
    　前記粘着層と前記伸縮フィルムとの間の粘着力は、前記伸縮フィルムと前記電池容器との間の接着力よりも強く、前記粘着層と前記基材層との間の粘着力よりも弱いことを特徴とする請求項１に記載の角形二次電池。     The adhesive film has a base material layer and an adhesive layer,
    The adhesive force between the adhesive layer and the stretchable film is stronger than the adhesive force between the stretchable film and the battery container, and weaker than the adhesive force between the adhesive layer and the base material layer. The prismatic secondary battery according to claim 1.
  12. 　前記粘着層と前記基材層との間の粘着力は、前記粘着層と前記電池容器との間の粘着力よりも強いことを特徴とする請求項１１に記載の角形二次電池。 The prismatic secondary battery according to claim 11, wherein the adhesive force between the adhesive layer and the base material layer is stronger than the adhesive force between the adhesive layer and the battery container.
  13. 　前記粘着フィルムは、着色されていることを特徴とする請求項２に記載の角形二次電池。 The prismatic secondary battery according to claim 2, wherein the adhesive film is colored.
  14. 　前記粘着フィルムは、前記正極外部端子側と前記負極外部端子側とで異なる色に着色されていることを特徴とする請求項１３に記載の角形二次電池。 The prismatic secondary battery according to claim 13, wherein the adhesive film is colored in different colors on the positive electrode external terminal side and the negative electrode external terminal side.
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