WO2015005227A1 - Film-packaged cell and method for manufacturing same - Google Patents

Film-packaged cell and method for manufacturing same Download PDF

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Publication number
WO2015005227A1
WO2015005227A1 PCT/JP2014/067824 JP2014067824W WO2015005227A1 WO 2015005227 A1 WO2015005227 A1 WO 2015005227A1 JP 2014067824 W JP2014067824 W JP 2014067824W WO 2015005227 A1 WO2015005227 A1 WO 2015005227A1
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WIPO (PCT)
Prior art keywords
hole
film
battery element
negative electrode
positive electrode
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PCT/JP2014/067824
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French (fr)
Japanese (ja)
Inventor
伸 田中
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Ｎｅｃエナジーデバイス株式会社
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Publication of WO2015005227A1 publication Critical patent/WO2015005227A1/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
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/04—Construction or manufacture in general
    • H01M10/0413—Large-sized flat cells or batteries for motive or stationary systems with plate-like electrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • 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
    • H01M50/342—Non-re-sealable arrangements
    • 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 film-clad battery in which battery elements are sealed with a film-like packaging material and a method for producing a film-clad battery.
  • non-aqueous electrolyte secondary battery serving as the power source for stationary power storage systems
  • the demand is growing.
  • a nonaqueous electrolyte secondary battery using a substance capable of inserting and extracting lithium has been proposed.
  • metal containers made of iron or aluminum that have been conventionally used as exterior materials in order to reduce the volume occupied by elements other than battery elements and to increase the energy and size of batteries instead of this, a film-clad battery using a film-like packaging material (hereinafter referred to as a packaging film) has attracted attention.
  • an exterior film can further reduce the thickness, and the structure can be freely selected.
  • the exterior film is formed in a structure in which a metal film such as an aluminum foil capable of preventing permeation of an electrolyte or gas and a resin film such as nylon, polyethylene, or polypropylene are bonded together.
  • a metal film such as an aluminum foil capable of preventing permeation of an electrolyte or gas
  • a resin film such as nylon, polyethylene, or polypropylene are bonded together.
  • the battery element is covered with two exterior films or an exterior film folded in two, and the outer periphery of the exterior film is sealed by thermal welding.
  • the stopping structure is widely adopted.
  • the exterior film is formed in a bag shape and the battery element is accommodated in the bag-shaped exterior film.
  • Patent Documents 1 and 2 disclose a configuration in which a safety valve is provided around the exterior film in order to prevent the gas from being blown out due to tearing of an unspecified portion of the sealing portion due to thermal welding of the outer peripheral portion of the film exterior battery. Yes.
  • the film-clad batteries described in Patent Documents 1 and 2 safely discharge gas to the outside of the exterior film when the internal pressure of the exterior film rises abnormally due to the generation of gas accompanying abnormal heat generation inside the exterior film. It is possible to release.
  • the present invention is a case where a small amount of gas is generated inside the exterior film without reducing the reliability of the sealed state of the battery element, as compared with the configuration in which the safety valve is disposed on the outer peripheral portion of the exterior film. Even if it exists, it aims at providing the manufacturing method of the film-clad battery which can discharge
  • a film-clad battery includes a battery element having a positive electrode and a negative electrode laminated via a separator, and an external film that surrounds and seals the battery element.
  • the positive electrode has a positive electrode through hole.
  • the separator has a separator through hole.
  • the negative electrode has a negative electrode through hole.
  • the battery element has a battery element through hole in which a positive electrode through hole, a separator through hole, and a negative electrode through hole communicate with each other along the stacking direction, and a part of the exterior film is welded inside the battery element through hole. . Inside the battery element through hole, a cut or opening is provided in a portion where the exterior film is welded.
  • the method for manufacturing a film-clad battery according to the present invention includes a positive electrode having a positive electrode through hole and a negative electrode having a negative electrode through hole stacked via a separator having a separator through hole.
  • a method for producing a film-clad battery comprising: a step of forming a cut or an opening in a welded part of the exterior film that is welded inside a battery element through hole.
  • the present invention when gas is generated inside the exterior film, it is possible to release the gas to the outside even when a small amount of gas is generated. For this reason, it is possible to prevent a large amount of gas from being blown out at a stretch from a part of the welded portion of the exterior film, thereby improving safety.
  • the film-clad battery 1 As shown in FIGS. 1 and 2, the film-clad battery 1 according to the embodiment is drawn out from the battery element 2 and the battery element 2 housed in the interior sealed by the upper and lower exterior films 8 and 9.
  • a negative electrode terminal 6 and a positive electrode terminal 5 as external terminals connected to the negative electrode current collector exposed portion 21 and the positive electrode current collector exposed portion 20, respectively, and an electrolyte.
  • the negative electrode 4 has a negative electrode active material 19 formed on a negative electrode current collector 18.
  • the negative electrode active material 19 formed in a slurry form is applied to both surfaces of the negative electrode current collector 18 made of a metal foil such as copper, and the negative electrode active material 19 is dried. Subsequently, the negative electrode 4 is formed by rolling the negative electrode current collector 18 having the negative electrode active material 19 formed thereon using a roll press. As shown in FIG.
  • the negative electrode 4 is formed with a slit-shaped negative electrode through hole 14 penetrating the center portion. Formation of the negative electrode through-hole 14 can be performed by processing using a press machine or the like after rolling of the negative electrode 4.
  • the opening shape of the negative electrode through hole 14 is not limited to a rectangle as shown in FIG. 2, and the shape is not limited to other rectangles such as a square, a polygon, a circle or an ellipse.
  • the opening area of the negative electrode through hole 14 is preferably as small as possible so that the energy density per battery is not significantly reduced.
  • the opening area of the negative electrode through hole 14 is preferably set to 10 mm 2 or more and 300 mm 2 or less in consideration of workability.
  • the positive electrode 3 has a positive electrode active material 17 formed on a positive electrode current collector 16.
  • a positive electrode active material 17 made of lithium cobaltate, lithium nickelate, lithium manganate, or a mixture containing at least one of them is mixed with a binder and a conductive agent such as acetylene black to form a slurry.
  • the positive electrode active material 17 is formed.
  • the positive electrode active material 17 formed in a slurry form is applied to both surfaces of the positive electrode current collector 16 made of a metal foil such as aluminum, and the positive electrode active material 17 is dried. Then, the positive electrode 3 is formed by rolling the positive electrode collector 16 in which the positive electrode active material 17 was formed using a roll press. As shown in FIG.
  • the positive electrode 3 is formed with a slit-shaped positive electrode through-hole 13 that penetrates the central portion.
  • the positive electrode through-hole 13 can be formed by processing using a press machine or the like after the positive electrode 3 is rolled.
  • the opening shape of the positive electrode through hole 13 may normally be the same opening shape as that of the negative electrode through hole 14, but may be different from the negative electrode through hole 14 as necessary.
  • a positive electrode through hole 13 is formed in the positive electrode 3 at a position corresponding to the negative electrode through hole 14 of the negative electrode 4 laminated together with the positive electrode 3.
  • the opening shape of the positive electrode through hole 13 is the same as the opening shape of the negative electrode through hole 14.
  • the opening size of the positive electrode through hole 13 is larger than that of the negative electrode through hole 14 and is formed so as to surround the opening shape of the negative electrode through hole 14.
  • the length and width of the opening of the positive electrode through hole 13 are formed larger than the length and width of the opening of the negative electrode through hole 14.
  • the separator 7 has slit-like separator through-holes 15 penetrating at positions corresponding to the negative electrode through-holes 14 of the negative electrode 4 and the positive electrode through-holes 13 of the positive electrode 3 laminated together with the separator 7. Is formed.
  • the opening shape and opening size of the separator through hole 15 are the same as and the same size as the opening shape of the negative electrode through hole 14.
  • the separator through hole 15 is formed such that the opening size is smaller than that of the negative electrode through hole 14 and is surrounded by the negative electrode through hole 14. As shown in FIGS.
  • the battery element 2 in which the positive electrode 3 and the negative electrode 4 are stacked via the separator 7 has the positive electrode through hole 13, the separator through hole 15, and the negative electrode through hole 14 along the stacking direction.
  • the battery element through-hole 10 is formed so as to communicate with each other.
  • the battery element through hole 10 is configured by aligning the center positions of the positive electrode through hole 13, the separator through hole 15 and the negative electrode through hole 14 along the stacking direction.
  • the positive electrode through hole 13 is the largest with respect to the opening cross-sectional area constituting the battery element through hole 10, and the positive electrode through hole 13, the negative electrode through hole 14, and the separator through hole 15 are formed in this order. ing.
  • a battery element 2 is formed by stacking a predetermined number of negative electrodes 4 and positive electrodes 3 with a separator 7 interposed between the negative electrodes 4 and the positive electrodes 3.
  • the separator 7 is made of polyethylene, polypropylene, or the like, and a large number of small holes (not shown) are provided throughout the separator 7.
  • the negative electrode terminal 6 is welded to the negative electrode current collector exposed portion 21 of the negative electrode 4.
  • the positive electrode terminal 5 is welded to the positive electrode current collector exposed portion 20 of the positive electrode 3.
  • the upper exterior film 8 and the lower exterior film 9 have a three-layer structure made of, for example, nylon, aluminum, and polypropylene.
  • the upper exterior film 8 and the lower exterior film 9 are processed by drawing so that the battery element accommodating portion 8 a is drawn into the upper exterior film 8 and the polypropylene side is inside the recess.
  • the drawing process for storing the battery element of the exterior film is not limited to the configuration provided in the upper exterior film as shown in FIG. 5, but may be provided in the lower exterior film or both the upper exterior film and the lower exterior film. . Further, as shown in FIG. 5 and FIG.
  • a convex portion is processed on the upper exterior film 8 so that the upper exterior film 8 and the lower exterior film 9 are welded inside the battery element through hole 10.
  • a cut 11 or an opening 12 is provided in a portion of the end face of the convex portion corresponding to the welded portion.
  • the convex part for welding the upper and lower outer film and the lower outer film is not limited to the configuration provided only in the upper outer film, but by adjusting the size of the lower outer film or the convex part. You may provide in both an upper exterior film and a lower exterior film.
  • interruption or opening provided in a convex part what is necessary is just to be provided in either one of an upper exterior film or a lower exterior film.
  • the shape of the opening 12 may be formed in the same shape as the negative electrode through hole 14 or the positive electrode through hole 13, but may be formed in a shape different from that of the negative electrode through hole 14 or the positive electrode through hole 13.
  • the opening 12 may be configured by arranging a plurality of small holes.
  • the battery element 2 is covered with the lower exterior film 9.
  • three sides of the outer periphery of the upper exterior film 8 and the lower exterior film 9 are welded, and the upper exterior film 8 and the lower exterior film 9 in the inner portion of the battery element through hole 10 are thermally welded.
  • an electrolytic solution is injected into the battery element storage portion 8a from one side of the outer peripheral portion of the upper and lower outer films 8 and 9 that is not thermally welded, and the outer heat film is vacuum-welded.
  • Battery 1 is produced.
  • a non-aqueous electrolytic solution having lithium ion conductivity is used as the electrolytic solution.
  • the battery element through-hole 10 is interposed more than the heat welding width represented by the minimum length from the outer peripheral edge of the upper exterior film 8 and the lower exterior film 9 to the unwelded portion of the battery element housing portion 8a.
  • the thermal welding width represented by the minimum length from the cut 11 or the opening 12 of the heat-welded portion to the unwelded portion in the vicinity of the battery element through hole 10 is reduced.
  • this embodiment compared with the form which does not have a safety valve, and the form where the safety valve is arranged on the outer peripheral part of the exterior film, this embodiment has a relatively small space for the exterior film to expand due to the generation of gas. Depending on the amount of gas generated, the welded portion inside the battery element through hole 10 is peeled off. As a result, since the cut 11 or the opening 12 is provided in at least one of the exterior films from which the inner side of the battery element through-hole 10 has been peeled off, the gas can be further safely released to the outside from the position of the cut 11 or the opening 12. It becomes possible to do.
  • the negative electrode active material 19 was formed on the negative electrode current collector 18 made of a copper foil having a thickness of 10 ⁇ m. A preparation was formed so that the negative electrode active material 19 made of graphite powder became a slurry together with a binder made of PVdF (polyvinylidene fluoride). The formed preparation was applied to both surfaces of the negative electrode current collector 18, the negative electrode active material 19 was dried, and rolled using a roll press to form the negative electrode 4.
  • PVdF polyvinylidene fluoride
  • the negative electrode active material 19 is applied to a rectangular region having a length of 200 mm and a width of 100 mm on the negative electrode current collector 18, and a rectangular negative electrode through hole having a length of 30 mm and a width of 6 mm is formed in the center of the negative electrode 4. 14 was formed.
  • the positive electrode active material 17 was formed on the positive electrode current collector 16 made of an aluminum foil having a thickness of 20 ⁇ m.
  • the positive electrode active material 17 made of lithium manganate was added with a binder made of PVdF and a conductive agent made of acetylene black to form a slurry.
  • the formed preparation was applied on both surfaces of the positive electrode current collector 16, the positive electrode active material 17 was dried, and rolled using a roll press to form the positive electrode 3.
  • the positive electrode active material 17 was applied to a rectangular region having an area of 198 mm in length and 98 mm in width on the positive electrode current collector 16.
  • a rectangular positive electrode through hole 12 having a length of 32 mm and a width of 8 mm was formed in the central portion of the positive electrode 3 corresponding to the negative electrode through hole 14 of the positive electrode 3.
  • the separator 7 was formed of a polyethylene nonwoven fabric having a length of 202 mm and a width of 102 mm.
  • a rectangular separator through hole 15 having a length of 28 mm and a width of 4 mm was formed in the center portion of the separator 7 corresponding to the negative electrode through hole 14 and the positive electrode through hole 13.
  • FIG. 3 nine negative electrodes 4 and eight positive electrodes 8 were laminated between a negative electrode 4 and a positive electrode 3 with a separator 7 therebetween, thereby producing a battery element 2.
  • the negative electrode terminal 6 was welded at the tip of the negative electrode current collector exposed portion 21.
  • the positive electrode terminal 5 was welded at the tip of the positive electrode current collector exposed portion 20.
  • the upper exterior film 8 and the lower exterior film 9 have a three-layer structure in which nylon / aluminum / polypropylene are laminated in this order.
  • a battery element storage portion 8a for storing the battery element 2 was formed by drawing so that the polypropylene side was inside the recess. Further, as shown in FIG.
  • the upper exterior film 8 is attached to the inner portion of the battery element through-hole 10 so that it can be thermally welded to the lower exterior film 9 through the inner portion of the battery element through-hole 10. Then, drawing was performed so that the polypropylene side was outside the convex portion. In addition, a cut 11 having a length of 15 mm was formed in the upper exterior film 8 at a portion welded to the lower exterior film 9 in the inner portion of the battery element through hole 10.
  • a battery element 2 comprising a negative electrode 4 to which a negative electrode terminal 6 is welded and a positive electrode 3 to which a positive electrode terminal 5 is welded and a separator 7 is accommodated in a battery element accommodating portion 8a formed on an upper exterior film 8, and the lower exterior
  • the battery element 2 was covered with the film 9.
  • the upper exterior film 8 and the lower exterior film 9 were thermally welded via three sides of the rectangular outer peripheral portion of the exterior film and the battery element through hole 10.
  • a film-clad battery 1 is produced by injecting an electrolyte into the battery element storage portion 8a from one side of the outer peripheral portion of the outer film that is not thermally welded, and thermally welding one side of the outer peripheral portion under vacuum. did.
  • the thermal welding width represented by the minimum length from the end where the upper outer packaging film 8 and the lower outer packaging film 9 were thermally welded to the non-welded portion was set to 5 mm in the outer peripheral portion of the film outer battery 1.
  • the minimum width represented by the minimum length from the cut line 11 of the heat welded part to the unwelded part was set to 1 mm.
  • a battery element not including the positive electrode through hole 13, the negative electrode through hole 14, and the separator through hole 15 was used.
  • a film-clad battery having the same configuration as that of the first example was prepared except that the upper and lower exterior films 8 and 9 were not welded via the battery element through holes 10. .
  • an opening 12 may be formed in the welded portion of the exterior film inside the battery element through hole 10 as shown in FIG. 6 instead of the cut 11 of the first example. Also in the second embodiment, the same operation and effect as the first embodiment can be obtained.
  • surroundings of opening of one exterior film are welded and sealed by the other exterior film.
  • the cut line 11 or the opening 12 formed inside the battery element through hole 10 is a part for releasing the gas generated inside the battery element 2, and the part around the cut line 11 or the opening 12 is an exterior film. If it is a form which is welded and sealed, it may be formed straddling both the upper and lower exterior films that are superimposed.
  • a pair of the upper and lower exterior films 8 and 9 whose outer peripheral portions are welded are used as the exterior films, but the present invention is not limited to this configuration.
  • an exterior film formed in a bag shape by being bonded or welded in advance except for a portion for projecting a part of the negative electrode terminal and the positive electrode terminal to the outside of the exterior film may be used.
  • the battery element is accommodated in a bag-shaped exterior film, and a portion for projecting a part of the negative electrode terminal and the positive electrode terminal to the outside of the exterior film is welded, and the battery element is sealed with the exterior film. Thereby, the welding location of the exterior film for sealing a battery element can be reduced.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Sealing Battery Cases Or Jackets (AREA)

Abstract

The present invention is provided with: a cell element (2) having a positive electrode (3) and a negative electrode (4) stacked with a separator (7) interposed therebetween; and an upper packaging film (8) and a lower packaging film (9) which surround and seal the cell element (2). The positive electrode (3) has a positive electrode through-hole (13), the separator (7) has a separator through-hole (15), and the negative electrode has a negative electrode through-hole (14). The cell element (2) has a cell element through-hole (10) resulting from the positive electrode through-hole (13), the separator through-hole (15), and the negative electrode through-hole (14) communicating with each other along the stacking direction. The upper packaging film (8) and the lower packaging film (9) are fused so as to produce a seal along the inside of the cell element through-hole (10). A cut (11) is provided at a portion, in the cell element through-hole (10), at which the upper packaging film (8) and the lower packaging film (9) are fused to each other.

Description

フィルム外装電池及びその製造方法Film-clad battery and manufacturing method thereof
　本発明は、フィルム状の外装材によって電池要素が封止されたフィルム外装電池及びフィルム外装電池の製造方法に関する。 The present invention relates to a film-clad battery in which battery elements are sealed with a film-like packaging material and a method for producing a film-clad battery.
　近年、電気自動車、ハイブリッド自動車、電気アシスト自転車や電動バイクを長時間稼働させるための駆動源、及び定置用蓄電システムの電源となる非水電解液二次電池の高エネルギー化及び高容量化への要求が高まっている。
　これらの要求を実現するために、リチウムを吸蔵及び放出できる物質を用いた非水電解液二次電池が提案されている。この非水電解液二次電池の中でも、電池要素以外が占める体積を削減し、電池の高エネルギー化及び小型化を図るために、従来から外装材として使用されていた鉄やアルミニウム製の金属容器の代わりに、フィルム状の外装材（以下、外装フィルムと称する）を使用したフィルム外装電池が注目されている。フィルム外装電池では、外装フィルムを使用することで、更なる薄肉化が可能であり、構造を自由に選ぶことが可能になる。　外装フィルムは、電解液やガスの透過を防止することが可能なアルミニウム箔などの金属膜と、ナイロン、ポリエチレン、ポリプロピレンなどの樹脂フィルムとを貼り合せた構造に形成されている。この種の金属ラミネート樹脂フィルムをフィルム外装電池の外装材として使用する場合には、２枚の外装フィルムまたは２つに折り畳んだ外装フィルムによって電池要素を覆い、外装フィルムの外周部を熱溶着によって封止する構造が広く採用されている。
　上述した構造以外には、外装フィルムを袋状に形成して、袋状の外装フィルムに電池要素を収納する構造がある。
　関連技術のフィルム外装電池では、内部短絡による電解液の分解等に伴って外装フィイムの内部にガスが多量に発生した場合、外装フィルムの熱溶着による封止部の一部が破れ、ガスが一気に噴き出することがある。このようにフィルム外装電池の外周部の熱溶着による封止部の不特定箇所の開裂によるガスの噴き出しを防ぐために、外装フィルムの周囲に安全弁を設ける構成が、特許文献１、２に開示されている。
　特許文献１、２に記載されたフィルム外装電池は、外装フィルムの内部の異常発熱等に伴うガスの発生によって外装フィルムの内部圧力が異常に上昇したときに、外装フィルムの外部にガスを安全に放出することが可能になっている。 In recent years, the drive source for operating electric vehicles, hybrid vehicles, electric assist bicycles and electric motorcycles for a long time, and the non-aqueous electrolyte secondary battery serving as the power source for stationary power storage systems has been increasing in energy and capacity. The demand is growing.
In order to realize these requirements, a nonaqueous electrolyte secondary battery using a substance capable of inserting and extracting lithium has been proposed. Among these non-aqueous electrolyte secondary batteries, metal containers made of iron or aluminum that have been conventionally used as exterior materials in order to reduce the volume occupied by elements other than battery elements and to increase the energy and size of batteries. Instead of this, a film-clad battery using a film-like packaging material (hereinafter referred to as a packaging film) has attracted attention. In a film-clad battery, the use of an exterior film can further reduce the thickness, and the structure can be freely selected. The exterior film is formed in a structure in which a metal film such as an aluminum foil capable of preventing permeation of an electrolyte or gas and a resin film such as nylon, polyethylene, or polypropylene are bonded together. When this type of metal laminated resin film is used as an exterior material for a film-clad battery, the battery element is covered with two exterior films or an exterior film folded in two, and the outer periphery of the exterior film is sealed by thermal welding. The stopping structure is widely adopted.
In addition to the structure described above, there is a structure in which the exterior film is formed in a bag shape and the battery element is accommodated in the bag-shaped exterior film.
In related art film-clad batteries, if a large amount of gas is generated inside the outer film due to decomposition of the electrolyte due to internal short circuit, etc., a part of the sealing part due to thermal welding of the outer film is broken, and the gas is blown all at once. May erupt. Patent Documents 1 and 2 disclose a configuration in which a safety valve is provided around the exterior film in order to prevent the gas from being blown out due to tearing of an unspecified portion of the sealing portion due to thermal welding of the outer peripheral portion of the film exterior battery. Yes.
The film-clad batteries described in Patent Documents 1 and 2 safely discharge gas to the outside of the exterior film when the internal pressure of the exterior film rises abnormally due to the generation of gas accompanying abnormal heat generation inside the exterior film. It is possible to release.
特開２００４－５５２９０号公報JP 2004-55290 A 特開２０１１－２３３７４７号公報JP 2011-233747 A
　しかしながら、特許文献１、２に記載された構造では、安全弁を作動させるために、外装フィルムが膨張し、内部の圧力が所定の圧力以上まで上昇する必要がある。そのため、特許文献１、２に記載されたフィルム外装電池において、外装フィルムの周囲に設けられた安全弁を、より少量のガスが発生したときに作動するように構成した場合には、電池要素の封止状態の信頼性を低下させてしまうおそれがあった。 However, in the structures described in Patent Documents 1 and 2, in order to operate the safety valve, the exterior film needs to expand and the internal pressure needs to rise to a predetermined pressure or higher. Therefore, in the film-clad batteries described in Patent Documents 1 and 2, when the safety valve provided around the exterior film is configured to operate when a smaller amount of gas is generated, the battery element is sealed. There was a risk of reducing the reliability of the stopped state.
　そこで、本発明は、外装フィルムの外周部に安全弁が配置される構成と比べて、電池要素の封止状態の信頼性を低下させることなく、外装フィルムの内部に少量のガスが発生したときであってもガスを外部に放出することができるフィルム外装電池及びフィルム外装電池の製造方法を提供することを目的とする。 Therefore, the present invention is a case where a small amount of gas is generated inside the exterior film without reducing the reliability of the sealed state of the battery element, as compared with the configuration in which the safety valve is disposed on the outer peripheral portion of the exterior film. Even if it exists, it aims at providing the manufacturing method of the film-clad battery which can discharge | release gas outside, and a film-clad battery.
　上述した目的を達成するため、本発明に係るフィルム外装電池は、セパレータを介して積層された正極と負極とを有する電池要素と、電池要素を包囲して封止する外装フィルムと、を備える。正極は正極貫通孔を有する。セパレータはセパレータ貫通孔を有する。負極は負極貫通孔を有する。電池要素は、正極貫通孔、セパレータ貫通孔及び負極貫通孔が積層方向に沿って互いに連通してなる電池要素貫通孔を有し、電池要素貫通孔の内部で外装フィルムの一部が溶着される。電池要素貫通孔の内部において、外装フィルムが溶着された部分に切れ目または開口が設けられる。 In order to achieve the above-described object, a film-clad battery according to the present invention includes a battery element having a positive electrode and a negative electrode laminated via a separator, and an external film that surrounds and seals the battery element. The positive electrode has a positive electrode through hole. The separator has a separator through hole. The negative electrode has a negative electrode through hole. The battery element has a battery element through hole in which a positive electrode through hole, a separator through hole, and a negative electrode through hole communicate with each other along the stacking direction, and a part of the exterior film is welded inside the battery element through hole. . Inside the battery element through hole, a cut or opening is provided in a portion where the exterior film is welded.
　また、本発明に係るフィルム外装電池の製造方法は、正極貫通孔を有する正極と、負極貫通孔を有する負極とを、セパレータ貫通孔を有するセパレータを介して積層し、正極貫通孔、負極貫通孔、セパレータ貫通孔が互いに連通された電池要素貫通孔を有する電池要素を形成する工程と、外装フィルムによって包囲された電池要素の電池要素貫通孔の内部で外装フィルムの一部を溶着する工程と、を有するフィルム外装電池の製造方法であって、電池要素貫通孔の内部で溶着される、外装フィルムの溶着部分に、切れ目または開口を形成する工程を有することを特徴とする。 In addition, the method for manufacturing a film-clad battery according to the present invention includes a positive electrode having a positive electrode through hole and a negative electrode having a negative electrode through hole stacked via a separator having a separator through hole. A step of forming a battery element having battery element through holes in which separator through holes communicate with each other; a step of welding a part of the exterior film inside the battery element through hole of the battery element surrounded by the exterior film; A method for producing a film-clad battery comprising: a step of forming a cut or an opening in a welded part of the exterior film that is welded inside a battery element through hole.
　本発明によれば、外装フィルムの内部にガスが発生した場合、少量のガスが発生したときであってもガスを外部に放出することが可能になる。このため、外装フィルムの溶着部の一部分から大量のガスが一気に噴き出することを防ぎ、安全性を高めることができる。 According to the present invention, when gas is generated inside the exterior film, it is possible to release the gas to the outside even when a small amount of gas is generated. For this reason, it is possible to prevent a large amount of gas from being blown out at a stretch from a part of the welded portion of the exterior film, thereby improving safety.
本実施形態のフィルム外装電池を示す斜視図である。It is a perspective view which shows the film-clad battery of this embodiment. 本実施形態のフィルム外装電池における電池要素の一部を模式的に示す斜視図である。It is a perspective view which shows typically a part of battery element in the film-clad battery of this embodiment. 本実施形態のフィルム外装電池における電池要素の一部を模式的に示す斜視図である。It is a perspective view which shows typically a part of battery element in the film-clad battery of this embodiment. 本実施形態のフィルム外装電池における電池要素を構成する正極、負極を示す平面図である。It is a top view which shows the positive electrode and negative electrode which comprise the battery element in the film-clad battery of this embodiment. 第１の実施例の外装フィルム電池が有する電池要素貫通孔部を示す断面図である。It is sectional drawing which shows the battery element through-hole part which the exterior film battery of a 1st Example has. 第２の実施例の外装フィルム電池が有する電池要素貫通孔部を示す断面図である。It is sectional drawing which shows the battery element through-hole part which the exterior film battery of a 2nd Example has.
　以下、本発明の実施形態について、図１～図６を参照して詳細に説明する。
　実施形態のフィルム外装電池１は、図１及び図２に示すように、上外装フィルム８と下外装フィルム９によって封止された内部に収納される電池要素２と、電池要素２から引き出された負極集電体露出部２１及び正極集電体露出部２０にそれぞれ接続された外部端子としての負極端子６及び正極端子５と、電解液と、を備えている。 Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS.
As shown in FIGS. 1 and 2, the film-clad battery 1 according to the embodiment is drawn out from the battery element 2 and the battery element 2 housed in the interior sealed by the upper and lower exterior films 8 and 9. A negative electrode terminal 6 and a positive electrode terminal 5 as external terminals connected to the negative electrode current collector exposed portion 21 and the positive electrode current collector exposed portion 20, respectively, and an electrolyte.
　図３に示すように、負極４は、負極集電体１８上に負極活物質１９が形成されてなる。リチウムを吸蔵及び放出する物質であるグラファイトやシリコンを含む粉末からなる負極活物質１９を、結着材と共に混ぜてスラリー状の負極活物質１９を形成する。スラリー状に形成された負極活物質１９を銅などの金属箔からなる負極集電体１８の両面に塗布して、負極活物質１９を乾燥する。続いて、負極活物質１９が形成された負極集電体１８を、ロールプレス機を用いて圧延することで負極４が形成されている。
　負極４には、図４に示すように、中央部を貫通するスリット状の負極貫通孔１４が形成されている。負極貫通孔１４の形成は、負極４の圧延後にプレス機等を用いた加工によって行うことができる。負極貫通孔１４の開口形状は、図２に示すような長方形に限定されるものではなく、正方形などの他の四角形や多角形、円形や楕円形など、形状を限定しない。しかし、電池１つ当たりのエネルギー密度を大きく低下させないように、負極貫通孔１４の開口面積は、可能な限り小さい方が好ましい。負極貫通孔１４の開口面積は、加工性を考慮した場合、１０ｍｍ2以上、３００ｍｍ2以下に設定することが望ましい。 As shown in FIG. 3, the negative electrode 4 has a negative electrode active material 19 formed on a negative electrode current collector 18. A negative electrode active material 19 made of a powder containing graphite or silicon, which is a material that absorbs and releases lithium, is mixed with a binder to form a slurry-like negative electrode active material 19. The negative electrode active material 19 formed in a slurry form is applied to both surfaces of the negative electrode current collector 18 made of a metal foil such as copper, and the negative electrode active material 19 is dried. Subsequently, the negative electrode 4 is formed by rolling the negative electrode current collector 18 having the negative electrode active material 19 formed thereon using a roll press.
As shown in FIG. 4, the negative electrode 4 is formed with a slit-shaped negative electrode through hole 14 penetrating the center portion. Formation of the negative electrode through-hole 14 can be performed by processing using a press machine or the like after rolling of the negative electrode 4. The opening shape of the negative electrode through hole 14 is not limited to a rectangle as shown in FIG. 2, and the shape is not limited to other rectangles such as a square, a polygon, a circle or an ellipse. However, the opening area of the negative electrode through hole 14 is preferably as small as possible so that the energy density per battery is not significantly reduced. The opening area of the negative electrode through hole 14 is preferably set to 10 mm 2 or more and 300 mm 2 or less in consideration of workability.
　図３に示すように、正極３は、正極集電体１６上に正極活物質１７が形成されてなる。コバルト酸リチウム、ニッケル酸リチウム、マンガン酸リチウムのいずれか、またはこれらを少なくとも１種類以上を含む混合物からなる正極活物質１７に、結着材とアセチレンブラックなどの導電剤とを共に混ぜてスラリー状の正極活物質１７を形成する。スラリー状に形成された正極活物質１７をアルミニウムなどの金属箔からなる正極集電体１６の両面に塗布して、正極活物質１７を乾燥する。続いて、正極活物質１７が形成された正極集電体１６を、ロールプレス機を用いて圧延することで正極３が形成されている。
　正極３には、図４に示すように、中央部を貫通するスリット状の正極貫通孔１３が形成されている。正極貫通孔１３は、正極３の圧延後にプレス機等を用いた加工によって形成することができる。正極貫通孔１３の開口形状は、通常は負極貫通孔１４と同様の開口形状とすればよいが、必要に応じて負極貫通孔１４と異なる開口形状としてもよい。
　図４に示すように、正極３には、正極３と一緒に積層する負極４の負極貫通孔１４に対応する位置に、正極貫通孔１３が形成されている。正極貫通孔１３の開口形状は、負極貫通孔１４の開口形状と同じ形状に形成されている。正極貫通孔１３の開口寸法は、負極貫通孔１４よりも大きくされて、負極貫通孔１４の開口形状を包囲するように形成されている。本実施形態では、正極貫通孔１３の開口の長さ及び幅は、負極貫通孔１４の開口の長さ及び幅よりも大きく形成されている。 As shown in FIG. 3, the positive electrode 3 has a positive electrode active material 17 formed on a positive electrode current collector 16. A positive electrode active material 17 made of lithium cobaltate, lithium nickelate, lithium manganate, or a mixture containing at least one of them is mixed with a binder and a conductive agent such as acetylene black to form a slurry. The positive electrode active material 17 is formed. The positive electrode active material 17 formed in a slurry form is applied to both surfaces of the positive electrode current collector 16 made of a metal foil such as aluminum, and the positive electrode active material 17 is dried. Then, the positive electrode 3 is formed by rolling the positive electrode collector 16 in which the positive electrode active material 17 was formed using a roll press.
As shown in FIG. 4, the positive electrode 3 is formed with a slit-shaped positive electrode through-hole 13 that penetrates the central portion. The positive electrode through-hole 13 can be formed by processing using a press machine or the like after the positive electrode 3 is rolled. The opening shape of the positive electrode through hole 13 may normally be the same opening shape as that of the negative electrode through hole 14, but may be different from the negative electrode through hole 14 as necessary.
As shown in FIG. 4, a positive electrode through hole 13 is formed in the positive electrode 3 at a position corresponding to the negative electrode through hole 14 of the negative electrode 4 laminated together with the positive electrode 3. The opening shape of the positive electrode through hole 13 is the same as the opening shape of the negative electrode through hole 14. The opening size of the positive electrode through hole 13 is larger than that of the negative electrode through hole 14 and is formed so as to surround the opening shape of the negative electrode through hole 14. In the present embodiment, the length and width of the opening of the positive electrode through hole 13 are formed larger than the length and width of the opening of the negative electrode through hole 14.
　図３に示すように、セパレータ７には、セパレータ７と一緒に積層する負極４の負極貫通孔１４及び正極３の正極貫通孔１３と対応する位置に、貫通するスリット状のセパレータ貫通孔１５が形成されている。セパレータ貫通孔１５の開口形状及び開口寸法は、負極貫通孔１４の開口形状と同じ形状、且つ同じ大きさに形成されている。あるいは、セパレータ貫通孔１５は、開口寸法が負極貫通孔１４よりも小さくされて、負極貫通孔１４によって包囲されるように形成されている。
　セパレータ７を介して正極３及び負極４が積層されてなる電池要素２は、図１及び図３に示すように、正極貫通孔１３、セパレータ貫通孔１５及び負極貫通孔１４が積層方向に沿って互いに連通してなる電池要素貫通孔１０を有している。電池要素貫通孔１０は、正極貫通孔１３、セパレータ貫通孔１５及び負極貫通孔１４の中心位置を積層方向に沿って一致させて構成されている。電池要素貫通孔１０を構成する開口断面積に関して、図３に示すように、正極貫通孔１３が最も大きく、正極貫通孔１３、負極貫通孔１４、セパレータ貫通孔１５の順に小さくなるように形成されている。
　負極４と正極３との間にセパレータ７を挟んで、所定の数量だけ負極４及び正極３を積層することで電池要素２を形成する。正極貫通孔１３の輪郭と負極貫通孔１４の輪郭とが重なっているか、または正極貫通孔１３の内側に負極貫通孔１４が包囲され、さらに負極貫通孔１４の内側にセパレータ貫通孔１５が包囲されるような大小関係になっている。このような大小関係を満たす正極貫通孔１３と負極貫通孔１４の構造を有することで、充放電中におけるリチウム金属の析出を防ぐことができる。
　セパレータ７は、ポリエチレンやポリプロピレンなどによって形成されており、セパレータ７の全体にわたって多数の小孔（不図示）が設けられている。
　また、負極端子６は、負極４の負極集電体露出部２１に溶接されている。また、正極端子５は、正極３の正極集電体露出部２０に溶接されている。 As shown in FIG. 3, the separator 7 has slit-like separator through-holes 15 penetrating at positions corresponding to the negative electrode through-holes 14 of the negative electrode 4 and the positive electrode through-holes 13 of the positive electrode 3 laminated together with the separator 7. Is formed. The opening shape and opening size of the separator through hole 15 are the same as and the same size as the opening shape of the negative electrode through hole 14. Alternatively, the separator through hole 15 is formed such that the opening size is smaller than that of the negative electrode through hole 14 and is surrounded by the negative electrode through hole 14.
As shown in FIGS. 1 and 3, the battery element 2 in which the positive electrode 3 and the negative electrode 4 are stacked via the separator 7 has the positive electrode through hole 13, the separator through hole 15, and the negative electrode through hole 14 along the stacking direction. The battery element through-hole 10 is formed so as to communicate with each other. The battery element through hole 10 is configured by aligning the center positions of the positive electrode through hole 13, the separator through hole 15 and the negative electrode through hole 14 along the stacking direction. As shown in FIG. 3, the positive electrode through hole 13 is the largest with respect to the opening cross-sectional area constituting the battery element through hole 10, and the positive electrode through hole 13, the negative electrode through hole 14, and the separator through hole 15 are formed in this order. ing.
A battery element 2 is formed by stacking a predetermined number of negative electrodes 4 and positive electrodes 3 with a separator 7 interposed between the negative electrodes 4 and the positive electrodes 3. The outline of the positive electrode through hole 13 and the outline of the negative electrode through hole 14 overlap, or the negative electrode through hole 14 is surrounded inside the positive electrode through hole 13, and the separator through hole 15 is surrounded inside the negative electrode through hole 14. It is a big and small relationship. By having the structure of the positive electrode through hole 13 and the negative electrode through hole 14 that satisfy such a magnitude relationship, it is possible to prevent lithium metal from being deposited during charging and discharging.
The separator 7 is made of polyethylene, polypropylene, or the like, and a large number of small holes (not shown) are provided throughout the separator 7.
The negative electrode terminal 6 is welded to the negative electrode current collector exposed portion 21 of the negative electrode 4. The positive electrode terminal 5 is welded to the positive electrode current collector exposed portion 20 of the positive electrode 3.
　図５に示すように、上外装フィルム８及び下外装フィルム９は、例えばナイロン、アルミニウム、ポリプロピレンからなる３層構造を有している。上外装フィルム８及び下外装フィルム９は、電池要素２を収納するために、絞り加工によって上外装フィルム８に電池要素収納部８ａが、ポリプロピレン側が凹部の内側となるように加工されている。外装フィルムの電池要素を収納するための絞り加工については、図５に示すように上外装フィルムに設ける構成に限らず、下外装フィルム、または上外装フィルム及び下外装フィルムの両方に設けてもよい。また、図５及び図６に示すように、電池要素貫通孔１０の内側において、上外装フィルム８と下外装フィルム９とが溶着されるように、上外装フィルム８に凸部が加工され、この凸部の端面の、溶着部に相当する部分に、切れ目１１または開口１２が設けられている。電池要素貫通孔の内部において、上外装フィルムと下外装フィルムとを溶着するための凸部は、上外装フィルムのみに設けられる構成に限らず、下外装フィルムまたは凸部の寸法を調整することで上外装フィルムと下外装フィルムの両方に設けられてもよい。また、凸部に設ける切れ目または開口については、上外装フィルムまたは下外装フィルムのいずれか一方に設けられればよい。
　なお、開口１２の形状としては、通常は負極貫通孔１４や正極貫通孔１３と同様の形状に形成すればよいが、負極貫通孔１４や正極貫通孔１３と異なる形状に形成されてもよい。また、開口１２は、複数の小孔を配列して構成されてもよい。 As shown in FIG. 5, the upper exterior film 8 and the lower exterior film 9 have a three-layer structure made of, for example, nylon, aluminum, and polypropylene. In order to accommodate the battery element 2, the upper exterior film 8 and the lower exterior film 9 are processed by drawing so that the battery element accommodating portion 8 a is drawn into the upper exterior film 8 and the polypropylene side is inside the recess. The drawing process for storing the battery element of the exterior film is not limited to the configuration provided in the upper exterior film as shown in FIG. 5, but may be provided in the lower exterior film or both the upper exterior film and the lower exterior film. . Further, as shown in FIG. 5 and FIG. 6, a convex portion is processed on the upper exterior film 8 so that the upper exterior film 8 and the lower exterior film 9 are welded inside the battery element through hole 10. A cut 11 or an opening 12 is provided in a portion of the end face of the convex portion corresponding to the welded portion. In the inside of the battery element through-hole, the convex part for welding the upper and lower outer film and the lower outer film is not limited to the configuration provided only in the upper outer film, but by adjusting the size of the lower outer film or the convex part. You may provide in both an upper exterior film and a lower exterior film. Moreover, about the cut | interruption or opening provided in a convex part, what is necessary is just to be provided in either one of an upper exterior film or a lower exterior film.
The shape of the opening 12 may be formed in the same shape as the negative electrode through hole 14 or the positive electrode through hole 13, but may be formed in a shape different from that of the negative electrode through hole 14 or the positive electrode through hole 13. The opening 12 may be configured by arranging a plurality of small holes.
　負極端子６が溶接された負極４と、正極端子５が溶接された正極３とが、セパレータ７を介して積層されてなる電池要素２を、上外装フィルム８の電池要素収納部８ａに収納し、下外装フィルム９によって電池要素２を覆う。続いて、上外装フィルム８及び下外装フィルム９の外周部のうちの三辺を溶着すると共に、電池要素貫通孔１０の内側部分の、上外装フィルム８と下外装フィルム９とを熱溶着する。次に、上外装フィルム８及び下外装フィルム９の外周部の、熱溶着されていない一辺から、電池要素収納部８ａに電解液を注液し、真空下にて熱溶着することで、フィルム外装電池１が作製される。電解液としては、リチウムイオン伝導性を有する非水電解液が用いられる。
　このとき、上外装フィルム８及び下外装フィルム９の外周部の端から、電池要素収容部８ａの未溶着部までの最小長さで表される熱溶着幅よりも、電池要素貫通孔１０を介した熱溶着部分の切れ目１１または開口１２から、電池要素貫通孔１０の近傍の未溶着部までの最小長さで表される熱溶着幅を小さくする。
　このような構造の電池要素貫通孔１０を備えることで、密封された外装フィルムの内部でガスが発生したときに、外装フィルムの外周部よりも先に、電池要素貫通孔１０の内側の溶着部分がガスの圧力で剥離することになる。このため、安全弁を有していない形態や、外装フィルムの外周部に安全弁が配置された形態と比べて、本実施形態は、ガスの発生によって外装フィルムが膨らむスペースが小さいので、相対的に少ないガスの発生量によって、電池要素貫通孔１０の内側で溶着された部分が剥がれる。その結果、電池要素貫通孔１０の内側が剥がれた、少なくとも一方の外装フィルムに、切れ目１１または開口１２が設けられているので、切れ目１１または開口１２の箇所から、外部にガスを更に安全に放出することが可能になる。 A battery element 2 in which a negative electrode 4 to which a negative electrode terminal 6 is welded and a positive electrode 3 to which a positive electrode terminal 5 is welded is laminated via a separator 7 is accommodated in a battery element accommodating portion 8 a of an upper exterior film 8. The battery element 2 is covered with the lower exterior film 9. Subsequently, three sides of the outer periphery of the upper exterior film 8 and the lower exterior film 9 are welded, and the upper exterior film 8 and the lower exterior film 9 in the inner portion of the battery element through hole 10 are thermally welded. Next, an electrolytic solution is injected into the battery element storage portion 8a from one side of the outer peripheral portion of the upper and lower outer films 8 and 9 that is not thermally welded, and the outer heat film is vacuum-welded. Battery 1 is produced. As the electrolytic solution, a non-aqueous electrolytic solution having lithium ion conductivity is used.
At this time, the battery element through-hole 10 is interposed more than the heat welding width represented by the minimum length from the outer peripheral edge of the upper exterior film 8 and the lower exterior film 9 to the unwelded portion of the battery element housing portion 8a. The thermal welding width represented by the minimum length from the cut 11 or the opening 12 of the heat-welded portion to the unwelded portion in the vicinity of the battery element through hole 10 is reduced.
By providing the battery element through hole 10 having such a structure, when gas is generated inside the sealed exterior film, the welded portion inside the battery element through hole 10 is ahead of the outer peripheral portion of the exterior film. Will be peeled off by gas pressure. For this reason, compared with the form which does not have a safety valve, and the form where the safety valve is arranged on the outer peripheral part of the exterior film, this embodiment has a relatively small space for the exterior film to expand due to the generation of gas. Depending on the amount of gas generated, the welded portion inside the battery element through hole 10 is peeled off. As a result, since the cut 11 or the opening 12 is provided in at least one of the exterior films from which the inner side of the battery element through-hole 10 has been peeled off, the gas can be further safely released to the outside from the position of the cut 11 or the opening 12. It becomes possible to do.
　（第１の実施例）
　以下、第１の実施例と比較例とを比較した結果について説明する。負極活物質１９は、厚さ１０μｍの銅箔からなる負極集電体１８上に形成した。グラファイト粉末からなる負極活物質１９を、ＰＶｄＦ（ポリフッ化ビニリデン）からなる結着材と共にスラリー状となるよう調剤を形成した。形成した調剤を負極集電体１８上の両面に塗布し、負極活物質１９を乾燥し、ロールプレス機を用いて圧延することで負極４を形成した。負極活物質１９を、負極集電体１８上の、長さ２００ｍｍ、幅１００ｍｍからなる面積の矩形領域に塗布し、負極４の中央部に、長さ３０ｍｍ、幅６ｍｍの矩形状の負極貫通孔１４を形成した。
　正極活物質１７は、厚さ２０μｍのアルミニウム箔からなる正極集電体１６上に形成した。マンガン酸リチウムからなる正極活物質１７に、ＰＶｄＦからなる結着材と、アセチレンブラックからなる導電剤とを添加してスラリー状となるように調剤を形成した。形成した調剤を、正極集電体１６上の両面に塗布、正極活物質１７を乾燥し、ロールプレス機を用いて圧延することで正極３が形成された。正極活物質１７を正極集電体１６上の、長さ１９８ｍｍ、幅９８ｍｍからなる面積の矩形領域に塗布した。また、正極３の、負極貫通孔１４に対応する正極３の中央部に、長さ３２ｍｍ、幅８ｍｍの矩形状の正極貫通孔１２を形成した。
　セパレータ７は、長さ２０２ｍｍ、幅１０２ｍｍのポリエチレン不織布によって形成した。また、セパレータ７の、負極貫通孔１４及び正極貫通孔１３に対応する中央部に、長さ２８ｍｍ、幅４ｍｍの矩形状のセパレータ貫通孔１５を形成した。 (First embodiment)
Hereinafter, the result of comparing the first example and the comparative example will be described. The negative electrode active material 19 was formed on the negative electrode current collector 18 made of a copper foil having a thickness of 10 μm. A preparation was formed so that the negative electrode active material 19 made of graphite powder became a slurry together with a binder made of PVdF (polyvinylidene fluoride). The formed preparation was applied to both surfaces of the negative electrode current collector 18, the negative electrode active material 19 was dried, and rolled using a roll press to form the negative electrode 4. The negative electrode active material 19 is applied to a rectangular region having a length of 200 mm and a width of 100 mm on the negative electrode current collector 18, and a rectangular negative electrode through hole having a length of 30 mm and a width of 6 mm is formed in the center of the negative electrode 4. 14 was formed.
The positive electrode active material 17 was formed on the positive electrode current collector 16 made of an aluminum foil having a thickness of 20 μm. The positive electrode active material 17 made of lithium manganate was added with a binder made of PVdF and a conductive agent made of acetylene black to form a slurry. The formed preparation was applied on both surfaces of the positive electrode current collector 16, the positive electrode active material 17 was dried, and rolled using a roll press to form the positive electrode 3. The positive electrode active material 17 was applied to a rectangular region having an area of 198 mm in length and 98 mm in width on the positive electrode current collector 16. In addition, a rectangular positive electrode through hole 12 having a length of 32 mm and a width of 8 mm was formed in the central portion of the positive electrode 3 corresponding to the negative electrode through hole 14 of the positive electrode 3.
The separator 7 was formed of a polyethylene nonwoven fabric having a length of 202 mm and a width of 102 mm. In addition, a rectangular separator through hole 15 having a length of 28 mm and a width of 4 mm was formed in the center portion of the separator 7 corresponding to the negative electrode through hole 14 and the positive electrode through hole 13.
　図３に示すように、負極４と正極３との間にセパレータ７を介して、９枚の負極４と、８枚の正極８とを積層して電池要素２を作製した。図２に示すように、負極端子６を負極集電体露出部２１の先端部で溶接した。また、正極端子５を正極集電体露出部２０の先端部で溶接した。上外装フィルム８及び下外装フィルム９は、ナイロン／アルミニウム／ポリプロピレンの順に積層された３層構造を有している。上外装フィルム８には、電池要素２を収納するための電池要素収納部８ａを、絞り加工によって、ポリプロピレン側が凹部の内側となるように形成した。また、上外装フィルム８には、図５に示すように、電池要素貫通孔１０の内側部分を介して下外装フィルム９と熱溶着することができるように、電池要素貫通孔１０の内側部分に、ポリプロピレン側が凸部の外側となるように絞り加工した。加えて、上外装フィルム８には、電池要素貫通孔１０の内側部分において、下外装フィルム９に溶着される部分に長さ１５ｍｍの切れ目１１を形成した。
　負極端子６が溶接された負極４及び正極端子５が溶接された正極３と、セパレータ７とからなる電池要素２を、上外装フィルム８に形成された電池要素収納部８ａに収納し、下外装フィルム９によって電池要素２を覆った。続いて、外装フィルムにおける矩形状の外周部のうちの三辺と、電池要素貫通孔１０とを介して、上外装フィルム８と下外装フィルム９を熱溶着した。外装フィルムの、熱溶着されていない外周部の一辺から、電池要素収納部８ａ内に電解液を注液し、真空下にて外周部の一辺を熱溶着することによって、フィルム外装電池１を作製した。このとき、フィルム外装電池１の外周部において、上外装フィルム８と下外装フィルム９が熱溶着された端から、未溶着部までの最小長さで表される熱溶着幅を５ｍｍに設定した。また、電池要素貫通孔１０の内側部分において、熱溶着部の切れ目１１から未溶着部までの最小長さで表される最小幅を１ｍｍに設定した。
　比較例としては、正極貫通孔１３、負極貫通孔１４及びセパレータ貫通孔１５を備えていない電池要素を用いた。また、比較例としては、上外装フィルム８と下外装フィルム９とが電池要素貫通孔１０を介して溶着されていない点以外が、第１の実施例と同じ構成であるフィルム外装電池を用意した。 As shown in FIG. 3, nine negative electrodes 4 and eight positive electrodes 8 were laminated between a negative electrode 4 and a positive electrode 3 with a separator 7 therebetween, thereby producing a battery element 2. As shown in FIG. 2, the negative electrode terminal 6 was welded at the tip of the negative electrode current collector exposed portion 21. The positive electrode terminal 5 was welded at the tip of the positive electrode current collector exposed portion 20. The upper exterior film 8 and the lower exterior film 9 have a three-layer structure in which nylon / aluminum / polypropylene are laminated in this order. In the upper exterior film 8, a battery element storage portion 8a for storing the battery element 2 was formed by drawing so that the polypropylene side was inside the recess. Further, as shown in FIG. 5, the upper exterior film 8 is attached to the inner portion of the battery element through-hole 10 so that it can be thermally welded to the lower exterior film 9 through the inner portion of the battery element through-hole 10. Then, drawing was performed so that the polypropylene side was outside the convex portion. In addition, a cut 11 having a length of 15 mm was formed in the upper exterior film 8 at a portion welded to the lower exterior film 9 in the inner portion of the battery element through hole 10.
A battery element 2 comprising a negative electrode 4 to which a negative electrode terminal 6 is welded and a positive electrode 3 to which a positive electrode terminal 5 is welded and a separator 7 is accommodated in a battery element accommodating portion 8a formed on an upper exterior film 8, and the lower exterior The battery element 2 was covered with the film 9. Subsequently, the upper exterior film 8 and the lower exterior film 9 were thermally welded via three sides of the rectangular outer peripheral portion of the exterior film and the battery element through hole 10. A film-clad battery 1 is produced by injecting an electrolyte into the battery element storage portion 8a from one side of the outer peripheral portion of the outer film that is not thermally welded, and thermally welding one side of the outer peripheral portion under vacuum. did. At this time, the thermal welding width represented by the minimum length from the end where the upper outer packaging film 8 and the lower outer packaging film 9 were thermally welded to the non-welded portion was set to 5 mm in the outer peripheral portion of the film outer battery 1. Moreover, in the inner part of the battery element through-hole 10, the minimum width represented by the minimum length from the cut line 11 of the heat welded part to the unwelded part was set to 1 mm.
As a comparative example, a battery element not including the positive electrode through hole 13, the negative electrode through hole 14, and the separator through hole 15 was used. Moreover, as a comparative example, a film-clad battery having the same configuration as that of the first example was prepared except that the upper and lower exterior films 8 and 9 were not welded via the battery element through holes 10. .
　〈比較結果〉
　第１の実施例のフィルム外装電池について、直流電源を用いて１００Ａの定電流充電による過電流試験を行い、外装フィルムの内部にガスを発生させた。第１の実施例のフィルム外装電池に関しては、試験を行った１０個全てにおいて、破裂することなく、内部に発生したガスが勢いよく噴出することなく、切れ目１１からガスが大気に開放された。比較例のフィルム外装電池に関しては、第１の実施例と同じ条件の過電流試験を行ったところ、試験を行った１０個全てにおいて、内部に発生したガスが勢いよく噴出した。
　以上の結果から、本発明によれば、電池要素２の封止状態の信頼性を低下させることなく、異常発熱等に伴うガスの発生によって生じた、外装フィルムの内部圧力の異常な上昇時に、より少量のガスが発生するだけでガスを安全に外部に開放できることができる。 <Comparison result>
About the film-clad battery of the 1st Example, the overcurrent test by 100 A constant current charge was performed using DC power supply, and gas was generated inside the exterior film. With respect to the film-clad batteries of the first example, in all 10 tested, the gas was released from the cut 11 to the atmosphere without bursting and without the gas generated inside expelling vigorously. Regarding the film-clad battery of the comparative example, an overcurrent test was performed under the same conditions as in the first example. As a result, the gas generated inside was vigorously ejected in all 10 tested.
From the above results, according to the present invention, without reducing the reliability of the sealed state of the battery element 2, when an abnormal increase in the internal pressure of the exterior film caused by the generation of gas accompanying abnormal heat generation, The gas can be safely released to the outside only by generating a smaller amount of gas.
　第２の実施例として、第１の実施例の切れ目１１の代わりに、図６に示すように、電池要素貫通孔１０の内部における外装フィルムの溶着部分に開口１２が形成されてもよい。第２の実施例においても、第１の実施例と同様の作用、効果を得ることができる。なお、一方の外装フィルムの開口の周囲は、他方の外装フィルムに溶着されて封止されている。
　電池要素貫通孔１０の内部に形成される切れ目１１または開口１２は、電池要素２の内部に生じたガスを放出させるための部分であって、切れ目１１または開口１２の周囲の部分が、外装フィルムが溶着されて封止されている形態であれば、重ね合わされた上外装フィルム及び下外装フィルムの両方に跨がって形成されてもよい。
　また、上述した実施形態では、外装フィルムとして外周部が溶着される一組の上外装フィルム８と下外装フィルム９が用いられたが、この構成に本発明が限定されるものではない。例えば、負極端子及び正極端子の一部を外装フィルムの外部に突出させるための箇所を除いて予め接合または溶着されることで袋状に形成された外装フィルムが用いられてもよい。この場合、袋状の外装フィルム内に電池要素を収容し、負極端子及び正極端子の一部を外装フィルムの外部に突出させるための箇所を溶着して、外装フィルムによって電池要素を封止する。これよって、電池要素を封止するための外装フィルムの溶着箇所を減らすことができる。 As a second example, an opening 12 may be formed in the welded portion of the exterior film inside the battery element through hole 10 as shown in FIG. 6 instead of the cut 11 of the first example. Also in the second embodiment, the same operation and effect as the first embodiment can be obtained. In addition, the circumference | surroundings of opening of one exterior film are welded and sealed by the other exterior film.
The cut line 11 or the opening 12 formed inside the battery element through hole 10 is a part for releasing the gas generated inside the battery element 2, and the part around the cut line 11 or the opening 12 is an exterior film. If it is a form which is welded and sealed, it may be formed straddling both the upper and lower exterior films that are superimposed.
In the above-described embodiment, a pair of the upper and lower exterior films 8 and 9 whose outer peripheral portions are welded are used as the exterior films, but the present invention is not limited to this configuration. For example, an exterior film formed in a bag shape by being bonded or welded in advance except for a portion for projecting a part of the negative electrode terminal and the positive electrode terminal to the outside of the exterior film may be used. In this case, the battery element is accommodated in a bag-shaped exterior film, and a portion for projecting a part of the negative electrode terminal and the positive electrode terminal to the outside of the exterior film is welded, and the battery element is sealed with the exterior film. Thereby, the welding location of the exterior film for sealing a battery element can be reduced.
　以上、実施形態を参照して本発明を説明したが、本発明は上記実施形態に限定されるものではない。本発明の構成や詳細に対して、本発明のスコープ内で当業者が理解し得る様々な変更を行うことができる。
　この出願は、２０１３年　７月１２日に出願された日本出願特願２０１３－１４６２１８を基礎とする優先権を主張し、その開示の全てをここに取り込む。 The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.
This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2013-146218 for which it applied on July 12, 2013, and takes in those the indications of all here.
　　１　フィルム外装電池
　　２　電池要素
　　３　正極
　　４　負極
　　５　正極端子
　　６　負極端子
　　７　セパレータ
　　８　上外装フィルム
　　９　下外装フィルム
　１０　電池要素貫通孔
　１１　切れ目
　１２　開口
　１３　正極貫通孔
　１４　負極貫通孔
　１５　セパレータ貫通孔 DESCRIPTION OF SYMBOLS 1 Film exterior battery 2 Battery element 3 Positive electrode 4 Negative electrode 5 Positive electrode terminal 6 Negative electrode terminal 7 Separator 8 Upper exterior film 9 Lower exterior film 10 Battery element through-hole 11 Break 12 Opening 13 Positive electrode through-hole 14 Negative electrode through-hole 15 Separator through-hole

Claims (5)

  1. 　セパレータを介して積層された正極と負極とを有する電池要素と、
    　前記電池要素を包囲して封止する外装フィルムと、を備え、
    　前記正極は正極貫通孔を有し、前記セパレータはセパレータ貫通孔を有し、前記負極は負極貫通孔を有し、
    　前記電池要素は、前記正極貫通孔、前記セパレータ貫通孔及び前記負極貫通孔が積層方向に沿って互いに連通してなる電池要素貫通孔を有し、該電池要素貫通孔の内部で前記外装フィルムの一部が溶着され、
    　前記電池要素貫通孔の内部において、前記外装フィルムが溶着された部分に切れ目または開口が設けられているフィルム外装電池。     A battery element having a positive electrode and a negative electrode laminated via a separator;
    An exterior film surrounding and sealing the battery element,
    The positive electrode has a positive electrode through hole, the separator has a separator through hole, the negative electrode has a negative electrode through hole,
    The battery element has a battery element through hole in which the positive electrode through hole, the separator through hole, and the negative electrode through hole communicate with each other along a stacking direction, and the battery element through hole is formed inside the battery element through hole. Some are welded,
    A film-clad battery in which a cut or an opening is provided in a portion where the exterior film is welded inside the battery element through hole.
  2. 　前記電池要素貫通孔は、前記正極貫通孔、前記負極貫通孔、前記セパレータ貫通孔の順に開口面積が小さくなる、請求項１に記載のフィルム外装電池。 2. The film-clad battery according to claim 1, wherein the battery element through hole has an opening area that decreases in order of the positive electrode through hole, the negative electrode through hole, and the separator through hole.
  3. 　前記外装フィルムは、第１の外装フィルム及び第２の外装フィルムを含み、前記第１の外装フィルム及び前記第２の外装フィルムによって前記電池要素を覆い、前記電池要素の周囲である外周部を溶着してなる、請求項１または２に記載のフィルム外装電池。 The exterior film includes a first exterior film and a second exterior film, covers the battery element with the first exterior film and the second exterior film, and welds an outer peripheral portion around the battery element. The film-clad battery according to claim 1 or 2.
  4. 　前記電池要素の内部には、リチウムイオン伝導性を有する非水電解液が含浸されている、請求項１乃至３のいずれか１項に記載のフィルム外装電池。 The film-clad battery according to any one of claims 1 to 3, wherein the battery element is impregnated with a non-aqueous electrolyte having lithium ion conductivity.
  5. 　正極貫通孔を有する正極と、負極貫通孔を有する負極とを、セパレータ貫通孔を有するセパレータを介して積層し、前記正極貫通孔、前記負極貫通孔、前記セパレータ貫通孔が互いに連通された電池要素貫通孔を有する電池要素を形成する工程と、
    　外装フィルムによって包囲された前記電池要素の前記電池要素貫通孔の内部で前記外装フィルムの一部を溶着する工程と、
    　前記電池要素貫通孔の内部で溶着される、前記外装フィルムの溶着部分に切れ目または開口を形成する工程と、を有するフィルム外装電池の製造方法。     A battery element in which a positive electrode having a positive electrode through hole and a negative electrode having a negative electrode through hole are stacked via a separator having a separator through hole, and the positive electrode through hole, the negative electrode through hole, and the separator through hole communicate with each other. Forming a battery element having a through hole;
    Welding a part of the exterior film inside the battery element through-hole of the battery element surrounded by the exterior film;
    Forming a cut or an opening in a welded portion of the exterior film, which is welded inside the battery element through hole.
PCT/JP2014/067824 2013-07-12 2014-07-03 Film-packaged cell and method for manufacturing same WO2015005227A1 (en)

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