WO2015072451A1 - Outer cladding material for lithium ion battery - Google Patents

Outer cladding material for lithium ion battery Download PDF

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Publication number
WO2015072451A1
WO2015072451A1 PCT/JP2014/079841 JP2014079841W WO2015072451A1 WO 2015072451 A1 WO2015072451 A1 WO 2015072451A1 JP 2014079841 W JP2014079841 W JP 2014079841W WO 2015072451 A1 WO2015072451 A1 WO 2015072451A1
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WO
WIPO (PCT)
Prior art keywords
layer
base material
material layer
adhesive
lithium ion
Prior art date
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PCT/JP2014/079841
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French (fr)
Japanese (ja)
Inventor
智昭 谷口
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凸版印刷株式会社
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Application filed by 凸版印刷株式会社 filed Critical 凸版印刷株式会社
Priority to CN201480061523.5A priority Critical patent/CN105706266A/en
Publication of WO2015072451A1 publication Critical patent/WO2015072451A1/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
    • H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
    • H01M50/116—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material
    • H01M50/124—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material having a layered structure
    • 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
    • H01M50/116—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material
    • H01M50/121—Organic material
    • 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
    • H01M50/116—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material
    • H01M50/117—Inorganic material
    • H01M50/119—Metals
    • 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
    • H01M50/116—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material
    • H01M50/124—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material having a layered structure
    • H01M50/126—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material having a layered structure comprising three or more layers
    • H01M50/129—Primary casings, jackets or wrappings of a single cell or a single battery characterised by the material having a layered structure comprising three or more layers with two or more layers of only organic material
    • 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
    • H01M50/131—Primary casings, jackets or wrappings of a single cell or a single battery characterised by physical properties, e.g. gas-permeability or size
    • H01M50/133—Thickness
    • 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
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • 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
    • H01M50/543—Terminals
    • H01M50/545—Terminals formed by the casing of the cells
    • 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 packaging material for a lithium ion battery.
  • This application claims priority based on Japanese Patent Application No. 2013-234082 for which it applied to Japan on November 12, 2013, and uses the content here.
  • nickel-metal hydride and lead-acid batteries are known as secondary batteries.
  • lithium ion batteries with high energy density have attracted attention because miniaturization of secondary batteries is essential due to miniaturization of portable devices and limitations on installation space.
  • metal cans have been used as exterior materials used in lithium-ion batteries (hereinafter sometimes referred to simply as “exterior materials”), but they are lightweight, have high heat dissipation, and are manufactured at low cost. Many possible multilayer films have been used.
  • the electrolyte of the lithium ion battery is composed of an aprotic solvent such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate, and an electrolyte.
  • an aprotic solvent such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate
  • electrolyte lithium salts such as LiPF 6 and LiBF 4 are used.
  • these lithium salts generate hydrofluoric acid by a hydrolysis reaction with moisture.
  • the hydrofluoric acid may cause corrosion of the metal surface of the battery member and decrease of the laminate strength between the respective layers of the exterior material formed from the multilayer film. Therefore, in the exterior material formed from the multilayer film, an aluminum foil layer is provided inside, and moisture is prevented from entering from the surface of the multilayer film.
  • a packaging material in which a heat-resistant base material layer / first adhesive layer / aluminum foil layer / corrosion prevention treatment layer for preventing corrosion due to hydrofluoric acid / second adhesive layer / sealant layer is sequentially laminated is known.
  • a lithium ion battery using such an exterior material is also called an aluminum laminate type lithium ion battery.
  • a recess is formed in a part of the exterior material by cold molding, and the battery contents such as a positive electrode, a separator, a negative electrode, an electrolyte solution are accommodated in the recess, A configuration in which the remaining part is folded and the edge part is sealed by heat sealing is known.
  • Such a battery is also called an embossed type lithium ion battery.
  • an embossed type lithium ion battery has also been manufactured in which recesses are formed on both sides of an exterior material to be bonded to accommodate more battery contents.
  • the energy density of a lithium ion battery increases as the recesses formed by cold forming become deeper. However, the deeper the recesses to be formed, the easier it is for pinholes and breaks during molding of the exterior material. Then, protecting metal foil using the biaxially stretched polyamide film for the base material layer of exterior material is performed.
  • the tensile strength until it breaks in a tensile test in four directions of 0 °, 45 °, 90 °, and 135 ° with respect to the tensile direction is 150 MPa, and 4 It has been proposed to use a film having an elongation in the direction of 80% or more as a base material layer (see, for example, Patent Document 1).
  • an object of the present invention is to provide an exterior material for a lithium ion battery capable of reducing the amount of warping after molding while maintaining excellent moldability.
  • An exterior material for a lithium ion battery includes a first base material layer formed of a polyester resin or a polyamide resin, and a polyester elastomer, and the second base material layer formed on the first base material layer.
  • a base material layer, a first adhesive layer laminated on the first base material layer, a metal foil layer laminated on the first adhesive layer, and the metal foil layer A laminated corrosion prevention treatment layer; a second adhesive layer formed on the corrosion prevention treatment layer; and a sealant layer formed on the second adhesion layer.
  • the thickness of the first base material layer is 4 ⁇ m or more and 20 ⁇ m or less
  • the thickness of the second base material layer is 2 ⁇ m or more and 15 ⁇ m or less
  • the thickness of the base material layer is 6 ⁇ m or more. It may be 25 ⁇ m or less.
  • the base material layer may be formed by a coextrusion method.
  • the amount of warpage after molding can be reduced while maintaining excellent moldability according to the exterior material for a lithium ion battery.
  • FIG. 3 is a cross-sectional view taken along line II in FIG. 2.
  • FIG. 1 is a cross-sectional view showing a lithium ion battery exterior material (hereinafter simply referred to as “exterior material”) 1 of the present embodiment.
  • the exterior material 1 has a sheet-like first adhesive layer 12, a metal foil layer 13, and a corrosion prevention treatment on one surface (first surface) of the sheet-like base material layer 11.
  • This is a laminate in which the layer 14, the second adhesive layer 15, and the sealant layer 16 are sequentially laminated.
  • the base material layer 11 becomes an outermost layer, and the sealant layer 16 becomes an innermost layer.
  • the base material layer 11 is a multilayer film
  • the exterior side of a battery is the 2nd base material layer 11b, and the layer which contact
  • the base material layer 11 provides heat resistance in a sealing process when manufacturing a lithium ion battery, and plays a role of suppressing generation of pinholes that may occur during processing and distribution.
  • the base material layer 11 has a multilayer structure having a first base material layer 11a and a second base material layer 11b.
  • the first base material layer 11a in contact with the first adhesive layer 12 is made of a polyester resin or a polyamide resin.
  • the second base material layer 11b laminated on the surface (second surface) 19 opposite to the surface (first surface) 18 in contact with the first adhesive layer 12 side of the first base material layer 11a is made of polyester elastomer. Contains.
  • the first base material layer 11a is preferably made of a polyamide (nylon) or polyester film having high strength, high elongation, and softness in order to form a thin and sharp shape. Furthermore, a biaxially stretched nylon (ONy) film or a biaxially stretched polyethylene terephthalate (PET) film is more preferable from the viewpoint of excellent puncture strength and impact strength. Among these, a biaxially stretched PET film is more preferable because the physical property value hardly changes depending on the moisture absorption state and the molding performance is stable.
  • the second base material layer 11b is a layer that relaxes the shrinkage rate of the base material layer 11 stretched by molding, and has a configuration containing a polyester elastomer so that the elastic limit (yield point) becomes small.
  • This configuration also has an advantage that the physical property value can be easily adjusted by the addition amount of the polyester elastomer.
  • the polyester elastomer contained in the second base material layer 11b has a hard segment and a soft segment.
  • the hard segment include crystalline polyesters such as polybutylene terephthalate, polybutylene naphthalate, and polyethylene terephthalate, and polybutylene terephthalate is particularly preferable.
  • the soft segment include polyoxyalkylene glycols such as polytetramethylene glycol, or polyesters such as polycaprolactone and polybutylene adipate, and polytetramethylene glycol is particularly preferable.
  • the thickness of the first base material layer 11a is preferably 4 ⁇ m to 20 ⁇ m, and more preferably 6 ⁇ m to 15 ⁇ m.
  • the thickness of the second base material layer 11b is preferably 2 ⁇ m to 15 ⁇ m, and more preferably 3 ⁇ m to 10 ⁇ m.
  • the thickness of the base material layer 11 is preferably 6 ⁇ m to 25 ⁇ m, and more preferably 10 ⁇ m to 20 ⁇ m. If the thickness of the 1st base material layer 11a is 4 micrometers or more and the thickness of the 2nd base material layer 11b is 15 micrometers or less, it is excellent in a moldability.
  • the shrinkage rate of the base material layer 11 at the location stretched by the molding process is not so large.
  • the shape after molding can be suitably maintained.
  • the base material layer 11 is preferably formed by a co-extrusion method capable of forming multiple layers at once and enabling the thinning of each layer.
  • the first adhesive layer 12 is a layer that bonds the base material layer 11 and the metal foil layer 13 together.
  • an adhesive constituting the first adhesive layer 12 a two-component curable type in which a bifunctional or higher functional aromatic or aliphatic isocyanate compound is allowed to act as a curing agent on a main component such as polyester polyol, polyether polyol, and acrylic polyol.
  • the urethane adhesive is preferable. Such a urethane-based adhesive is subjected to, for example, aging at 40 ° C. for 4 days or more after coating, whereby the reaction between the hydroxyl group of the main agent and the isocyanate group of the curing agent proceeds to enable strong adhesion.
  • the thickness of the first adhesive layer 12 is preferably 1 to 10 ⁇ m, more preferably 3 to 7 ⁇ m, from the viewpoint of adhesive strength, followability, workability, and the like.
  • Metal foil layer 13 As the metal foil layer 13, various metal foils such as aluminum and stainless steel can be used, and aluminum foil is preferable from the viewpoint of workability such as moisture resistance and spreadability and cost. A general soft aluminum foil can be used as the aluminum foil. Among these, an aluminum foil containing iron is preferable from the viewpoint of excellent pinhole resistance and extensibility during molding.
  • the content of iron in the aluminum foil containing iron (100% by mass) is preferably 0.1 to 9.0% by mass, and more preferably 0.5 to 2.0% by mass. When the iron content is 0.1% by mass or more, the exterior material 1 is excellent in pinhole resistance and spreadability. If the iron content is 9.0% by mass or less, the exterior material 1 is excellent in flexibility.
  • the thickness of the metal foil layer 13 is preferably 9 to 200 ⁇ m, more preferably 15 to 100 ⁇ m, from the viewpoint of barrier properties, pinhole resistance, and workability.
  • the corrosion prevention treatment layer 14 serves to suppress the corrosion of the metal foil layer 13 due to the electrolytic solution or hydrofluoric acid generated by the reaction between the electrolytic solution and moisture. Further, it plays a role of increasing the adhesion between the metal foil layer 13 and the second adhesive layer 15.
  • a coating film formed by a coating type or immersion type acid resistant corrosion prevention treatment agent is preferable. Such a coating film is excellent in the effect of preventing corrosion of the metal foil layer 13 against acid. Moreover, since such a coating film strengthens the adhesive force of the metal foil layer 13 and the 2nd contact bonding layer 15 by an anchor effect, the outstanding tolerance with respect to contents, such as electrolyte solution, is acquired.
  • the coating film constituting the corrosion prevention treatment layer 14 for example, a coating film formed by ceriazol treatment with a corrosion prevention treatment agent having cerium oxide, phosphate and various thermosetting resins, chromate, phosphoric acid Examples thereof include a coating film formed by chromate treatment with a corrosion prevention treatment agent having a salt, fluoride and various thermosetting resins.
  • the corrosion prevention treatment layer 14 is not limited to the above-described coating film as long as the corrosion resistance of the metal foil layer 13 is sufficiently obtained.
  • a coating film formed by phosphate treatment, boehmite treatment, or the like may be used.
  • the corrosion prevention treatment layer 14 may be a single layer or a plurality of layers.
  • an additive such as a silane coupling agent may be added to the corrosion prevention treatment layer 14.
  • the thickness of the corrosion prevention treatment layer 14 is preferably 10 nm to 5 ⁇ m, more preferably 20 to 500 nm, from the viewpoint of the corrosion prevention function and the function as an anchor.
  • the corrosion prevention process layer 14 may be further provided between the 1st contact bonding layer 12 and the metal foil layer 13 according to a required function.
  • the second adhesive layer 15 is a layer that bonds the metal foil layer 13 on which the corrosion prevention treatment layer 14 is formed and the sealant layer 16.
  • the exterior material 1 is roughly divided into a thermal laminate configuration and a dry laminate configuration depending on the adhesive component forming the second adhesive layer 15.
  • an adhesive component for forming the second adhesive layer 15 in the thermal laminate configuration an acid-modified polyolefin resin obtained by graft-modifying a polyolefin resin with an acid such as maleic anhydride is preferable.
  • a polar group is introduced into a part of the non-polar polyolefin-based resin.
  • the acid-modified polyolefin resin can be firmly adhered to both the nonpolar sealant layer 16 formed of a polyolefin resin film or the like and the polar corrosion prevention treatment layer 14.
  • the acid-modified polyolefin resin resistance to contents such as electrolyte solution is improved, and even if hydrofluoric acid is generated inside the battery, a decrease in adhesion due to deterioration of the second adhesive layer 15 is prevented. easy.
  • the acid-modified polyolefin resin used for the second adhesive layer 15 may be one type or two or more types.
  • polyolefin resin used for the acid-modified polyolefin resin examples include low density, medium density, and high density polyethylene; ethylene- ⁇ olefin copolymer; homopropylene, block propylene, or random polypropylene; propylene- ⁇ olefin copolymer Examples include coalescence.
  • copolymers obtained by copolymerizing polar molecules such as acrylic acid and methacrylic acid, polymers such as crosslinked polyolefin, and the like can also be used.
  • the acid that modifies the polyolefin-based resin examples include carboxylic acid, epoxy compound, acid anhydride and the like, and maleic anhydride is preferable.
  • a polyolefin resin is grafted with maleic anhydride from the viewpoint that the adhesive force between the sealant layer 16 and the metal foil layer 13 can be easily maintained even when the electrolyte permeates.
  • a modified maleic anhydride-modified polyolefin resin is preferable, and maleic anhydride-modified polypropylene is particularly preferable.
  • the modification rate of maleic anhydride-modified polypropylene with maleic anhydride is preferably 0.1 to 20% by mass, preferably 0.3 to 5% by mass. % Is more preferable.
  • the second adhesive layer 15 having a heat laminate structure preferably contains a styrene elastomer or an olefin elastomer. Thereby, it is easy to suppress that the second adhesive layer 15 is cracked and whitened at the time of cold forming, and it is expected that the adhesion is improved by improving the wettability and the film forming property is improved by reducing the anisotropy. .
  • These elastomers are preferably dispersed and compatible with each other in the order of nanometers in the acid-modified polyolefin resin.
  • the second adhesive layer 15 in the thermal laminate configuration can be formed by extruding the above-described adhesive component with an extrusion device.
  • the melt flow rate (MFR) of the adhesive component is preferably 4 to 30 g / 10 min under the conditions of 230 ° C. and 2.16 kgf.
  • the thickness of the second adhesive layer 15 in the heat laminate configuration is preferably 2 to 50 ⁇ m.
  • the second adhesive layer 15 in the dry laminate configuration for example, a two-component curable polyurethane adhesive similar to the component mentioned in the first adhesive layer 12 may be used.
  • the second adhesive layer 15 in the dry laminate configuration has a highly hydrolyzable bonding portion such as an ester group or a urethane group. Therefore, the second adhesive layer 15 having a heat laminate structure is preferable for applications that require higher reliability.
  • the sealant layer 16 is a layer that imparts sealing properties by heat sealing in the exterior material 1.
  • the sealant layer 16 include a resin film formed from a polyolefin resin or an acid-modified polyolefin resin obtained by graft-modifying an acid such as maleic anhydride to a polyolefin resin.
  • the polyolefin resin include low density, medium density, and high density polyethylene; ethylene- ⁇ olefin copolymer; homopolypropylene, block polypropylene, or random polypropylene; propylene- ⁇ olefin copolymer. These polyolefin resin may be used individually by 1 type, and may use 2 or more types together.
  • the acid-modified polyolefin resin include the same type as the resin exemplified in the second adhesive layer 15.
  • the sealant layer 16 may be a single layer film or a multilayer film, and may be selected according to a required function. For example, in terms of imparting moisture resistance, a multilayer film in which a resin such as an ethylene-cycloolefin copolymer or polymethylpentene is interposed can be used.
  • the sealant layer 16 may be blended with various additives such as a flame retardant, slip agent, anti-blocking agent, antioxidant, light stabilizer, and tackifier.
  • the thickness of the sealant layer 16 is preferably 10 to 100 ⁇ m, and more preferably 20 to 60 ⁇ m.
  • the exterior material 1 may have a configuration in which a sealant layer 16 is laminated by dry lamination.
  • the sealant layer 16 is laminated by sandwich lamination in which the second adhesive layer 15 is formed from an acid-modified polyolefin resin.
  • the manufacturing method of the exterior material 1 is demonstrated.
  • the following content is an example, and the manufacturing method of the exterior material 1 is not limited to the following content.
  • Examples of the manufacturing method of the packaging material 1 include a method having the following steps (1) to (3).
  • Step (1) A step of forming a corrosion prevention treatment layer 14 on the metal foil layer 13.
  • Step (2) A step of bonding the base material layer 11 through the first adhesive layer 12 to the surface of the metal foil layer 13 opposite to the surface on which the corrosion prevention treatment layer 14 is formed.
  • Step (3) A step of bonding the sealant layer 16 to the corrosion prevention treatment layer 14 formed on the metal foil layer 13 via the second adhesive layer 15.
  • a corrosion prevention treatment agent is applied to one surface (first surface) of the metal foil layer 13 and dried to form the corrosion prevention treatment layer 14.
  • the anti-corrosion treatment agent include the above-described anti-corrosion treatment agent for ceriazole treatment, anti-corrosion treatment agent for chromate treatment, and the like.
  • the coating method of the corrosion inhibitor is not particularly limited, and various methods such as gravure coating, reverse coating, roll coating, and bar coating can be employed.
  • the base material layer is formed by a technique such as dry lamination using an adhesive for forming the first adhesive layer 12 on the surface (second surface) opposite to the surface on which the corrosion prevention treatment layer 14 is formed in the metal foil layer 13. 11 is pasted together.
  • an aging treatment (curing) may be performed in the range of room temperature to 100 ° C. in order to promote adhesion.
  • a second adhesive layer 15 is formed by extrusion lamination on the corrosion prevention treatment layer 14 of the laminate in which the base material layer 11, the first adhesion layer 12, the metal foil layer 13, and the corrosion prevention treatment layer 14 are laminated in this order. Then, a resin film for forming the sealant layer 16 is bonded. The lamination of the sealant layer 16 is preferably performed by sandwich lamination.
  • the exterior material 1 is obtained by the steps (1) to (3) described above. Note that the process sequence of the manufacturing method of the packaging material 1 is not limited to the method of sequentially performing the above (1) to (3). For example, step (1) may be performed after performing step (2).
  • FIG. 2 is a plan view of the packaging material 1
  • FIG. 3 is a cross-sectional view taken along the line II of FIG.
  • a molding method for forming the molding processing area 17 shown in FIGS. 2 and 3 as a concave portion having a rectangular shape in plan view in the exterior material 1 in the process of manufacturing a lithium ion battery will be described.
  • the molding process area 17 is formed, for example, by pressing a pressing member having a rectangular pressure surface against a part of the exterior material 1 in the thickness direction. Moreover, it is preferable to form the pressing position, that is, the molding area 17 at a position deviated from the center of the exterior material 1 cut into a rectangle as shown in FIGS. If it does in this way, the part by which the molding process area 17 of the cladding
  • a lithium ion battery is manufactured by performing the following steps on the exterior material 1. That is, after forming the molding process area 17 as a recess as in the above process, the positive electrode, the separator, and the negative electrode are placed inside the recess. Thereafter, the exterior material 1 is folded back and overlapped so that the sealant layers face each other, and the two sides are heat-sealed. Thereafter, in a vacuum state, an electrolyte is injected from the remaining side, and the remaining side is heat-sealed and sealed to form a lithium ion battery.
  • the lithium ion battery using the exterior material for lithium ion batteries of this invention is not limited to the structure manufactured by the said method.
  • a lithium ion battery may be formed by preparing two exterior members 1 and bonding the sealant layers 16 so as to face each other.
  • the metal foil layer 13 is protected and the moldability is improved by forming the first base material layer 11a with a polyester resin or a polyamide resin. Is possible. Further, since the second base material layer 11b contains the polyester elastomer, it is possible to reduce the amount of warping of the exterior material after the molding process.
  • the thickness of the first base material layer 11a is set to 4 ⁇ m to 20 ⁇ m
  • the thickness of the second base material layer 11b is set to 2 ⁇ m to 15 ⁇ m so that the moldability is improved and the exterior after molding is processed. It becomes possible to reduce the amount of warping of the material.
  • the base material layer 11 by the coextrusion method, the first base material layer 11a and the second base material layer 11b can be thinned.
  • the packaging material and secondary battery of the present invention will be further described with reference to examples and comparative examples, but the present invention is not limited at all based on the specific contents of the examples.
  • [Materials used] First, the material of each layer used in Examples and Comparative Examples is shown below. (Base material layer) Table 1 shows the structures of the base material layers used in Examples 1 to 7 and Comparative Examples 1 to 5.
  • Adhesive B-1 Polyester urethane adhesive
  • Metal foil layer Metal foil C-1: Soft aluminum foil 8079 (Toyo Aluminum Co., Ltd., thickness 40 ⁇ m)
  • Treatment agent D-1 Treatment agent for coating-type ceriazole treatment mainly composed of cerium oxide, phosphoric acid and acrylic resin
  • Adhesive resin E-1 Polypropylene resin graft-modified with maleic anhydride (trade name “Admer”, manufactured by Mitsui Chemicals, Inc.)
  • Film F-1 Film obtained by corona-treating the inner surface of an unstretched polypropylene film (thickness 40 ⁇ m)
  • Treatment agent D-1 was applied to one surface of metal foil C-1 to be a metal foil layer and dried to form a corrosion prevention treatment layer.
  • any one of the substrates A-1 to A-12 is formed on the surface of the metal foil layer opposite to the surface on which the corrosion prevention treatment layer is formed by a dry laminating method using an adhesive B-1. Were pasted together. Thereafter, aging was performed at 60 ° C. for 6 days.
  • a second adhesive layer is formed by extruding the adhesive resin E-1 on the corrosion prevention treatment layer of the obtained laminate with an extruder, and the sealant layer is formed by laminating and bonding the film F-1. Formed.
  • the obtained laminate, 190 ° C. was created exterior material by heat pressing at 4kg / cm 2, 2m / min conditions.
  • the exterior material obtained in each example was cut into a 120 mm ⁇ 260 mm blank shape with the long side of the tensile elongation obtained in the tensile evaluation as the long side, and the molding depth was 3 mm in a molding environment of 23 ° C. and 40% RH. And cold forming was performed.
  • the molding area was 25 mm from the end of the blank shape, and molding was performed in a state of being brought to one side of the blank shape.
  • As the punch a punch having a shape of 70 mm ⁇ 80 mm, RCP of 1.5 mm, RP of 0.75 mm, and RD of 0.75 mm was used.
  • the molded exterior material is fixed to a flat reference surface so that the base material layer side of the molding area faces up, and the warping amount of the edge of the unmolded area after 60 minutes from the molding process (from the reference surface) Distance) was measured. Evaluation criteria were performed according to the following. E (excellent): Warpage amount is less than 50 mm F (fair): Warpage amount is 50 mm or more and less than 100 mm I (insufficient): Warpage amount is 100 mm or more
  • Table 2 shows the evaluation results of moldability and post-molding warpage amount of Examples 1 to 7 and Comparative Examples 1 to 5.
  • Examples 1 to 7 having the configuration according to an embodiment of the present invention it was possible to provide a packaging material for a lithium ion battery that can obtain sufficient moldability and can reduce the amount of warping after molding.

Abstract

This outer cladding material (1) for a lithium ion battery has: a substrate layer (11) having a first substrate layer (11a) formed from a polyester resin or a polyamide resin and a second substrate layer (11b) containing a polyester elastomer and formed on the first substrate layer (11a); a first adhesive layer (12) laminated on the first substrate layer (11a); a metal foil layer (13) laminated on the first substrate layer (12); a corrosion prevention treatment layer (14) laminated on the metal foil layer (13); a second adhesive layer (15) formed on the corrosion prevention treatment layer (14); and a sealant layer (16) formed on the second adhesive layer (15).

Description

リチウムイオン電池用外装材Exterior materials for lithium-ion batteries
　本発明は、リチウムイオン電池用外装材に関する。
　本願は、２０１３年１１月１２日に日本に出願された特願２０１３－２３４０８２号に基づき優先権を主張し、その内容をここに援用する。 The present invention relates to a packaging material for a lithium ion battery.
This application claims priority based on Japanese Patent Application No. 2013-234082 for which it applied to Japan on November 12, 2013, and uses the content here.
　従来、二次電池としてはニッケル水素、鉛蓄電池が知られている。一方、携帯機器の小型化や設置スペースの制限等により二次電池の小型化が必須となっているため、エネルギー密度が高いリチウムイオン電池が注目されている。リチウムイオン電池に用いられる外装材（以下、単に「外装材」ということがある。）としては、従来は金属製の缶が用いられていたが、軽量で、放熱性が高く、低コストで製造できる多層フィルムが多く用いられるようになっている。 Conventionally, nickel-metal hydride and lead-acid batteries are known as secondary batteries. On the other hand, lithium ion batteries with high energy density have attracted attention because miniaturization of secondary batteries is essential due to miniaturization of portable devices and limitations on installation space. Conventionally, metal cans have been used as exterior materials used in lithium-ion batteries (hereinafter sometimes referred to simply as “exterior materials”), but they are lightweight, have high heat dissipation, and are manufactured at low cost. Many possible multilayer films have been used.
　リチウムイオン電池の電解液は、炭酸プロピレン、炭酸エチレン、炭酸ジメチル、炭酸ジエチル、炭酸エチルメチルなどの非プロトン性の溶媒と電解質とから構成される。電解質としては、ＬｉＰＦ６、ＬｉＢＦ４などのリチウム塩が用いられる。しかし、これらのリチウム塩は水分による加水分解反応によりフッ酸を発生する。フッ酸は電池部材の金属面の腐食や、多層フィルムから形成される外装材の各層間のラミネート強度の低下を引き起こすことがある。
　そこで、多層フィルムから形成される外装材では内部にアルミニウム箔層が設けられ、多層フィルムの表面から水分が入ることを抑制している。たとえば、耐熱性を有する基材層／第１接着層／アルミニウム箔層／フッ酸による腐食を防止する腐食防止処理層／第２接着層／シーラント層が順次積層された外装材が知られている。このような外装材を使用したリチウムイオン電池は、アルミラミネートタイプのリチウムイオン電池とも呼ばれる。 The electrolyte of the lithium ion battery is composed of an aprotic solvent such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate, and an electrolyte. As the electrolyte, lithium salts such as LiPF 6 and LiBF 4 are used. However, these lithium salts generate hydrofluoric acid by a hydrolysis reaction with moisture. The hydrofluoric acid may cause corrosion of the metal surface of the battery member and decrease of the laminate strength between the respective layers of the exterior material formed from the multilayer film.
Therefore, in the exterior material formed from the multilayer film, an aluminum foil layer is provided inside, and moisture is prevented from entering from the surface of the multilayer film. For example, a packaging material in which a heat-resistant base material layer / first adhesive layer / aluminum foil layer / corrosion prevention treatment layer for preventing corrosion due to hydrofluoric acid / second adhesive layer / sealant layer is sequentially laminated is known. . A lithium ion battery using such an exterior material is also called an aluminum laminate type lithium ion battery.
　アルミラミネートタイプのリチウムイオン電池の一種として、外装材の一部に冷間成型によって凹部を形成し、該凹部内に正極、セパレータ、負極、電解液等の電池内容物を収容し、外装材の残りの部分を折り返して縁部分をヒートシールで封止した構成が知られている。このような電池は、エンボスタイプのリチウムイオン電池とも呼ばれる。近年では、エネルギー密度を高める目的で、貼り合わせる外装材の両側に凹部を形成し、より多くの電池内容物を収容できるようにしたエンボスタイプのリチウムイオン電池も製造されている。 As a kind of aluminum laminate type lithium ion battery, a recess is formed in a part of the exterior material by cold molding, and the battery contents such as a positive electrode, a separator, a negative electrode, an electrolyte solution are accommodated in the recess, A configuration in which the remaining part is folded and the edge part is sealed by heat sealing is known. Such a battery is also called an embossed type lithium ion battery. In recent years, for the purpose of increasing the energy density, an embossed type lithium ion battery has also been manufactured in which recesses are formed on both sides of an exterior material to be bonded to accommodate more battery contents.
　リチウムイオン電池のエネルギー密度は、冷間成型によって形成する凹部を深くするほど高くなる。しかし、形成する凹部が深いほど、外装材の成型時にピンホールや破断が起こり易くなる。そこで、外装材の基材層に二軸延伸ポリアミドフィルムを用いて金属箔を保護することが行われている。 The energy density of a lithium ion battery increases as the recesses formed by cold forming become deeper. However, the deeper the recesses to be formed, the easier it is for pinholes and breaks during molding of the exterior material. Then, protecting metal foil using the biaxially stretched polyamide film for the base material layer of exterior material is performed.
　外装材の成型性を向上させる従来技術として、引張方向に対する０°、４５°、９０°、１３５°の４方向においての引張試験で破断するまでの引張強さがいずれも１５０ＭＰａであり、かつ４方向における伸びが８０％以上であるフィルムを基材層として用いることが提案されている（例えば、特許文献１参照。）。 As a conventional technique for improving the moldability of the exterior material, the tensile strength until it breaks in a tensile test in four directions of 0 °, 45 °, 90 °, and 135 ° with respect to the tensile direction is 150 MPa, and 4 It has been proposed to use a film having an elongation in the direction of 80% or more as a base material layer (see, for example, Patent Document 1).
日本国特許第３５６７２３０号公報Japanese Patent No. 3567230
　しかしながら、特許文献１の技術では、成型加工後の反りに関して何ら考慮されていない。そのため、外装材を延伸しながら成型加工した際に、延伸された基材層が元の状態に戻ろうとするために発生する反りが改善できないという問題がある。 However, in the technique of Patent Document 1, no consideration is given to warpage after molding. Therefore, there is a problem that when the exterior material is molded while being stretched, warping that occurs because the stretched base material layer tends to return to its original state cannot be improved.
　上記事情を踏まえ、本発明は、優れた成型性を維持しつつ、成型加工後の反り量を低減することが可能なリチウムイオン電池用外装材の提供を目的とする。 In view of the above circumstances, an object of the present invention is to provide an exterior material for a lithium ion battery capable of reducing the amount of warping after molding while maintaining excellent moldability.
　本発明の一態様に係るリチウムイオン電池用外装材は、ポリエステル樹脂またはポリアミド樹脂で形成された第１基材層と、ポリエステルエラストマーを含有し、前記第１基材層上に形成された第２基材層と、を有する基材層と、前記第１基材層上に積層された第１接着層と、前記第１接着層上に積層された金属箔層と、前記金属箔層上に積層された腐食防止処理層と、前記腐食防止処理層上に形成された第２接着層と、前記第２接着層上に形成されたシーラント層と、を有する。 An exterior material for a lithium ion battery according to an aspect of the present invention includes a first base material layer formed of a polyester resin or a polyamide resin, and a polyester elastomer, and the second base material layer formed on the first base material layer. A base material layer, a first adhesive layer laminated on the first base material layer, a metal foil layer laminated on the first adhesive layer, and the metal foil layer A laminated corrosion prevention treatment layer; a second adhesive layer formed on the corrosion prevention treatment layer; and a sealant layer formed on the second adhesion layer.
　上記一態様において、前記第１基材層の厚さが４μｍ以上２０μｍ以下であり、前記第２基材層の厚さが２μｍ以上１５μｍ以下であり、前記基材層の厚さが６μｍ以上、２５μｍ以下であってもよい。　 In the one aspect, the thickness of the first base material layer is 4 μm or more and 20 μm or less, the thickness of the second base material layer is 2 μm or more and 15 μm or less, and the thickness of the base material layer is 6 μm or more. It may be 25 μm or less. *
　上記一態様において、前記基材層が共押出し法で形成されてもよい。　 In the above aspect, the base material layer may be formed by a coextrusion method. *
　本発明の上記態様によれば、リチウムイオン電池用外装材によれば、優れた成型性を維持しつつ、成型加工後の反り量を低減することができる。 According to the above aspect of the present invention, the amount of warpage after molding can be reduced while maintaining excellent moldability according to the exterior material for a lithium ion battery.
本発明の一実施形態に係るリチウムイオン電池用外装材を示す断面図である。It is sectional drawing which shows the exterior material for lithium ion batteries which concerns on one Embodiment of this invention. 本発明の一実施形態に係るリチウムイオン電池用外装材の平面図である。It is a top view of the exterior material for lithium ion batteries which concerns on one Embodiment of this invention. 図２のＩ－Ｉ線における断面図である。FIG. 3 is a cross-sectional view taken along line II in FIG. 2.
　本発明の一実施形態について、図１から図３を参照して説明する。図１は、本実施形態のリチウムイオン電池用外装材（以下、単に「外装材」と称する。）１を示す断面図である。
　外装材１は、図１に示すように、シート状の基材層１１の一方の面（第１の面）に、同じくそれぞれシート状の第１接着層１２、金属箔層１３、腐食防止処理層１４、第２接着層１５、及びシーラント層１６が順次積層された積層体である。外装材１を用いてリチウムイオン電池を形成する際は、基材層１１が最外層となり、シーラント層１６が最内層となる。また、基材層１１は多層フィルムであり、電池の外部側が第２基材層１１ｂであり、第１接着層１２に接する層が第１基材層１１aである。 An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing a lithium ion battery exterior material (hereinafter simply referred to as “exterior material”) 1 of the present embodiment.
As shown in FIG. 1, the exterior material 1 has a sheet-like first adhesive layer 12, a metal foil layer 13, and a corrosion prevention treatment on one surface (first surface) of the sheet-like base material layer 11. This is a laminate in which the layer 14, the second adhesive layer 15, and the sealant layer 16 are sequentially laminated. When forming a lithium ion battery using the exterior material 1, the base material layer 11 becomes an outermost layer, and the sealant layer 16 becomes an innermost layer. Moreover, the base material layer 11 is a multilayer film, the exterior side of a battery is the 2nd base material layer 11b, and the layer which contact | connects the 1st contact bonding layer 12 is the 1st base material layer 11a.
［基材層１１］
　基材層１１は、リチウムイオン電池を製造する際のシール工程における耐熱性を付与し、加工や流通の際に起こり得るピンホールの発生を抑制する役割を果たす。
　基材層１１は、第１基材層１１ａおよび第２基材層１１ｂを有する多層構成である。第１接着層１２に接する第１基材層１１ａは、ポリエステル樹脂またはポリアミド樹脂からなる。第１基材層１１ａの第１接着層１２側と接する面（第１の面）１８と反対側の面（第２の面）１９に積層された第２基材層１１ｂは、ポリエステルエラストマーを含有している。 [Base material layer 11]
The base material layer 11 provides heat resistance in a sealing process when manufacturing a lithium ion battery, and plays a role of suppressing generation of pinholes that may occur during processing and distribution.
The base material layer 11 has a multilayer structure having a first base material layer 11a and a second base material layer 11b. The first base material layer 11a in contact with the first adhesive layer 12 is made of a polyester resin or a polyamide resin. The second base material layer 11b laminated on the surface (second surface) 19 opposite to the surface (first surface) 18 in contact with the first adhesive layer 12 side of the first base material layer 11a is made of polyester elastomer. Contains.
　第１基材層１１ａは、薄肉で、シャープな形状の成型を行うために、強度が高く、伸びが大きく、かつ軟質であるポリアミド（ナイロン）またはポリエステルのフィルムを使用することが好ましい。さらに、突刺強度、衝撃強度に優れる点から二軸延伸ナイロン（ＯＮｙ）フィルム又は二軸延伸ポリエチレンテレフタレート（ＰＥＴ）フィルムがより好ましい。中でも、吸湿状態により物性値が変化しにくく、成型性能が安定する二軸延伸ＰＥＴフィルムがさらに好ましい。 The first base material layer 11a is preferably made of a polyamide (nylon) or polyester film having high strength, high elongation, and softness in order to form a thin and sharp shape. Furthermore, a biaxially stretched nylon (ONy) film or a biaxially stretched polyethylene terephthalate (PET) film is more preferable from the viewpoint of excellent puncture strength and impact strength. Among these, a biaxially stretched PET film is more preferable because the physical property value hardly changes depending on the moisture absorption state and the molding performance is stable.
　第２基材層１１ｂは、成型加工により延伸された基材層１１の収縮率を緩和する層であり、弾性限界（降伏点）が小さくなるよう、ポリエステルエラストマーを含有する構成を有する。この構成には、ポリエステルエラストマーの添加量により容易に物性値を調整できるという利点もある。 The second base material layer 11b is a layer that relaxes the shrinkage rate of the base material layer 11 stretched by molding, and has a configuration containing a polyester elastomer so that the elastic limit (yield point) becomes small. This configuration also has an advantage that the physical property value can be easily adjusted by the addition amount of the polyester elastomer.
　第２基材層１１ｂに含有されるポリエステルエラストマーは、ハードセグメントとソフトセグメントとを有する。ハードセグメントはポリブチレンテレフタレート、ポリブチレンナフタレート、ポリエチレンテレフタレートなどの結晶性ポリエステルが挙げられ、特にポリブチレンテレフタレートが好ましい。ソフトセグメントはポリテトラメチレングリコールなどのポリオキシアルキレングリコール類、または、ポリカプロラクトン、ポリブチレンアジペートなどのポリエステルが挙げられ、特にポリテトラメチレングリコールが好ましい。 The polyester elastomer contained in the second base material layer 11b has a hard segment and a soft segment. Examples of the hard segment include crystalline polyesters such as polybutylene terephthalate, polybutylene naphthalate, and polyethylene terephthalate, and polybutylene terephthalate is particularly preferable. Examples of the soft segment include polyoxyalkylene glycols such as polytetramethylene glycol, or polyesters such as polycaprolactone and polybutylene adipate, and polytetramethylene glycol is particularly preferable.
　第１基材層１１ａの厚さは、４μｍ～２０μｍが好ましく、６μｍ～１５μｍがより好ましい。
　また、第２基材層１１ｂの厚さは、２μｍ～１５μｍが好ましく、３μｍ～１０μｍがより好ましい。
　基材層１１の厚さとしては、６μｍ～２５μｍが好ましく、１０μｍ～２０μｍがより好ましい。
　第１基材層１１ａの厚さが４μｍ以上かつ第２基材層１１ｂの厚さが１５μｍ以下であれば成型性に優れる。第１基材層１１ａの厚さが２０μｍ以下かつ第２基材層１１ｂの厚さが２μｍ以上であれば、成型加工により延伸された箇所における基材層１１の収縮率がそれほど大きくならず、成型加工後の形状を好適に維持できる。 The thickness of the first base material layer 11a is preferably 4 μm to 20 μm, and more preferably 6 μm to 15 μm.
The thickness of the second base material layer 11b is preferably 2 μm to 15 μm, and more preferably 3 μm to 10 μm.
The thickness of the base material layer 11 is preferably 6 μm to 25 μm, and more preferably 10 μm to 20 μm.
If the thickness of the 1st base material layer 11a is 4 micrometers or more and the thickness of the 2nd base material layer 11b is 15 micrometers or less, it is excellent in a moldability. If the thickness of the first base material layer 11a is 20 μm or less and the thickness of the second base material layer 11b is 2 μm or more, the shrinkage rate of the base material layer 11 at the location stretched by the molding process is not so large. The shape after molding can be suitably maintained.
　基材層１１は、多層を一度に形成でき、各層の薄膜化も可能となる共押出し法で形成されていることが好ましい。 The base material layer 11 is preferably formed by a co-extrusion method capable of forming multiple layers at once and enabling the thinning of each layer.
［第１接着層１２］
　第１接着層１２は、基材層１１と金属箔層１３とを接着する層である。
　第１接着層１２を構成する接着材としては、ポリエステルポリオール、ポリエーテルポリオール、アクリルポリオール等の主剤に、硬化剤として２官能以上の芳香族系又は脂肪族系イソシアネート化合物を作用させる２液硬化型のウレタン系接着剤が好ましい。このようなウレタン系接着剤は、塗工後、例えば４０℃で４日以上のエージングを行うことで、主剤の水酸基と硬化剤のイソシアネート基との反応が進行して強固な接着が可能となる。
　第１接着層１２の厚さは、接着強度、追随性、加工性などの点から、１～１０μｍが好ましく、３～７μｍがより好ましい。 [First adhesive layer 12]
The first adhesive layer 12 is a layer that bonds the base material layer 11 and the metal foil layer 13 together.
As an adhesive constituting the first adhesive layer 12, a two-component curable type in which a bifunctional or higher functional aromatic or aliphatic isocyanate compound is allowed to act as a curing agent on a main component such as polyester polyol, polyether polyol, and acrylic polyol. The urethane adhesive is preferable. Such a urethane-based adhesive is subjected to, for example, aging at 40 ° C. for 4 days or more after coating, whereby the reaction between the hydroxyl group of the main agent and the isocyanate group of the curing agent proceeds to enable strong adhesion. .
The thickness of the first adhesive layer 12 is preferably 1 to 10 μm, more preferably 3 to 7 μm, from the viewpoint of adhesive strength, followability, workability, and the like.
［金属箔層１３］
　金属箔層１３としては、アルミニウム、ステンレス鋼等の各種金属箔を使用することができ、防湿性、延展性等の加工性、コストの面から、アルミニウム箔が好ましい。アルミニウム箔としては、一般の軟質アルミニウム箔を用いることができる。なかでも、耐ピンホール性、および成形時の延展性に優れる点から、鉄を含むアルミニウム箔が好ましい。
　鉄を含むアルミニウム箔（１００質量％）中の鉄の含有量は、０．１～９．０質量％が好ましく、０．５～２．０質量％がより好ましい。鉄の含有量が０．１質量％以上であれば、外装材１は耐ピンホール性、延展性に優れる。鉄の含有量が９．０質量％以下であれば外装材１は柔軟性に優れる。 [Metal foil layer 13]
As the metal foil layer 13, various metal foils such as aluminum and stainless steel can be used, and aluminum foil is preferable from the viewpoint of workability such as moisture resistance and spreadability and cost. A general soft aluminum foil can be used as the aluminum foil. Among these, an aluminum foil containing iron is preferable from the viewpoint of excellent pinhole resistance and extensibility during molding.
The content of iron in the aluminum foil containing iron (100% by mass) is preferably 0.1 to 9.0% by mass, and more preferably 0.5 to 2.0% by mass. When the iron content is 0.1% by mass or more, the exterior material 1 is excellent in pinhole resistance and spreadability. If the iron content is 9.0% by mass or less, the exterior material 1 is excellent in flexibility.
　金属箔層１３の厚さは、バリア性、耐ピンホール性、加工性の点から、９～２００μｍが好ましく、１５～１００μｍがより好ましい。 The thickness of the metal foil layer 13 is preferably 9 to 200 μm, more preferably 15 to 100 μm, from the viewpoint of barrier properties, pinhole resistance, and workability.
［腐食防止処理層１４］
　腐食防止処理層１４は、電解液や、電解液と水分の反応により発生するフッ酸による金属箔層１３の腐食を抑制する役割を果たす。また、金属箔層１３と第２接着層１５との密着力を高める役割を果たす。
　腐食防止処理層１４としては、塗布型、又は浸漬型の耐酸性の腐食防止処理剤によって形成された塗膜が好ましい。このような塗膜は、金属箔層１３の酸に対する腐食防止効果に優れる。また、このような塗膜は、アンカー効果によって金属箔層１３と第２接着層１５との密着力をより強固にするため、電解液等の内容物に対して優れた耐性が得られる。 [Corrosion prevention treatment layer 14]
The corrosion prevention treatment layer 14 serves to suppress the corrosion of the metal foil layer 13 due to the electrolytic solution or hydrofluoric acid generated by the reaction between the electrolytic solution and moisture. Further, it plays a role of increasing the adhesion between the metal foil layer 13 and the second adhesive layer 15.
As the corrosion prevention treatment layer 14, a coating film formed by a coating type or immersion type acid resistant corrosion prevention treatment agent is preferable. Such a coating film is excellent in the effect of preventing corrosion of the metal foil layer 13 against acid. Moreover, since such a coating film strengthens the adhesive force of the metal foil layer 13 and the 2nd contact bonding layer 15 by an anchor effect, the outstanding tolerance with respect to contents, such as electrolyte solution, is acquired.
　腐食防止処理層１４を構成する塗膜としては、例えば、酸化セリウムとリン酸塩と各種熱硬化性樹脂とを有する腐食防止処理剤によるセリアゾール処理によって形成される塗膜、クロム酸塩、リン酸塩、フッ化物と各種熱硬化性樹脂とを有する腐食防止処理剤によるクロメート処理により形成される塗膜等が挙げられる。
　腐食防止処理層１４は、金属箔層１３の耐食性が充分に得られる塗膜であれば、上述した塗膜には限定されない。例えば、リン酸塩処理、ベーマイト処理等によって形成した塗膜であってもよい。 As the coating film constituting the corrosion prevention treatment layer 14, for example, a coating film formed by ceriazol treatment with a corrosion prevention treatment agent having cerium oxide, phosphate and various thermosetting resins, chromate, phosphoric acid Examples thereof include a coating film formed by chromate treatment with a corrosion prevention treatment agent having a salt, fluoride and various thermosetting resins.
The corrosion prevention treatment layer 14 is not limited to the above-described coating film as long as the corrosion resistance of the metal foil layer 13 is sufficiently obtained. For example, a coating film formed by phosphate treatment, boehmite treatment, or the like may be used.
　腐食防止処理層１４は、単層であってもよく、複数層であってもよい。また、腐食防止処理層１４には、シラン系カップリング剤等の添加剤が添加されてもよい。
　腐食防止処理層１４の厚さは、腐食防止機能、及びアンカーとしての機能の点から、１０ｎｍ～５μｍが好ましく、２０～５００ｎｍがより好ましい。
　なお、腐食防止処理層１４は、必要な機能に応じて第１接着層１２と金属箔層１３との間にさらに設けられてもよい。 The corrosion prevention treatment layer 14 may be a single layer or a plurality of layers. In addition, an additive such as a silane coupling agent may be added to the corrosion prevention treatment layer 14.
The thickness of the corrosion prevention treatment layer 14 is preferably 10 nm to 5 μm, more preferably 20 to 500 nm, from the viewpoint of the corrosion prevention function and the function as an anchor.
In addition, the corrosion prevention process layer 14 may be further provided between the 1st contact bonding layer 12 and the metal foil layer 13 according to a required function.
［第２接着層１５］
　第２接着層１５は、腐食防止処理層１４が形成された金属箔層１３とシーラント層１６とを接着する層である。外装材１は、第２接着層１５を形成する接着成分によって、熱ラミネート構成とドライラミネート構成との大きく二つに分けられる。
　熱ラミネート構成における第２接着層１５を形成する接着成分としては、ポリオレフィン系樹脂を無水マレイン酸等の酸でグラフト変性した酸変性ポリオレフィン系樹脂が好ましい。酸変性ポリオレフィン系樹脂は、無極性であるポリオレフィン系樹脂の一部に極性基が導入されている。そのため、酸変性ポリオレフィン系樹脂は、ポリオレフィン系樹脂フィルム等で形成した無極性のシーラント層１６と、極性を有する腐食防止処理層１４との両方に強固に密着することができる。また、酸変性ポリオレフィン系樹脂を使用することで、電解液等の内容物に対する耐性が向上し、電池内部でフッ酸が発生しても第２接着層１５の劣化による密着力の低下を防止し易い。
　第２接着層１５に使用する酸変性ポリオレフィン系樹脂は、１種であってもよく、２種以上であってもよい。 [Second adhesive layer 15]
The second adhesive layer 15 is a layer that bonds the metal foil layer 13 on which the corrosion prevention treatment layer 14 is formed and the sealant layer 16. The exterior material 1 is roughly divided into a thermal laminate configuration and a dry laminate configuration depending on the adhesive component forming the second adhesive layer 15.
As an adhesive component for forming the second adhesive layer 15 in the thermal laminate configuration, an acid-modified polyolefin resin obtained by graft-modifying a polyolefin resin with an acid such as maleic anhydride is preferable. In the acid-modified polyolefin-based resin, a polar group is introduced into a part of the non-polar polyolefin-based resin. Therefore, the acid-modified polyolefin resin can be firmly adhered to both the nonpolar sealant layer 16 formed of a polyolefin resin film or the like and the polar corrosion prevention treatment layer 14. In addition, by using acid-modified polyolefin resin, resistance to contents such as electrolyte solution is improved, and even if hydrofluoric acid is generated inside the battery, a decrease in adhesion due to deterioration of the second adhesive layer 15 is prevented. easy.
The acid-modified polyolefin resin used for the second adhesive layer 15 may be one type or two or more types.
　酸変性ポリオレフィン系樹脂に用いるポリオレフィン系樹脂としては、例えば、低密度、中密度、高密度のポリエチレン；エチレン－αオレフィン共重合体；ホモプロピレン、ブロックプロピレン、又はランダムポリプロピレン；プロピレン－αオレフィン共重合体等が挙げられる。また、これらにアクリル酸やメタクリル酸等の極性分子を共重合させた共重合体や、架橋ポリオレフィン等の重合体等も使用できる。
　前記ポリオレフィン系樹脂を変性する酸としては、カルボン酸、エポキシ化合物、酸無水物等が挙げられ、無水マレイン酸が好ましい。 Examples of the polyolefin resin used for the acid-modified polyolefin resin include low density, medium density, and high density polyethylene; ethylene-α olefin copolymer; homopropylene, block propylene, or random polypropylene; propylene-α olefin copolymer Examples include coalescence. In addition, copolymers obtained by copolymerizing polar molecules such as acrylic acid and methacrylic acid, polymers such as crosslinked polyolefin, and the like can also be used.
Examples of the acid that modifies the polyolefin-based resin include carboxylic acid, epoxy compound, acid anhydride and the like, and maleic anhydride is preferable.
　熱ラミネート構成における第２接着層１５の接着成分としては、電解液が浸透してきてもシーラント層１６と金属箔層１３との密着力を維持しやすい点から、ポリオレフィン系樹脂を無水マレイン酸でグラフト変性させた、無水マレイン酸変性ポリオレフィン系樹脂が好ましく、無水マレイン酸変性ポリプロピレンが特に好ましい。
　無水マレイン酸変性ポリプロピレンの無水マレイン酸による変性率（無水マレイン酸変性ポリプロピレンの総質量に対する無水マレイン酸に由来する部分の質量）は、０．１～２０質量％が好ましく、０．３～５質量％がより好ましい。 As an adhesive component of the second adhesive layer 15 in the thermal laminate configuration, a polyolefin resin is grafted with maleic anhydride from the viewpoint that the adhesive force between the sealant layer 16 and the metal foil layer 13 can be easily maintained even when the electrolyte permeates. A modified maleic anhydride-modified polyolefin resin is preferable, and maleic anhydride-modified polypropylene is particularly preferable.
The modification rate of maleic anhydride-modified polypropylene with maleic anhydride (the mass of the portion derived from maleic anhydride relative to the total mass of maleic anhydride-modified polypropylene) is preferably 0.1 to 20% by mass, preferably 0.3 to 5% by mass. % Is more preferable.
　熱ラミネート構成の第２接着層１５中には、スチレン系エラストマー又はオレフィン系エラストマーが含有されていることが好ましい。これにより、冷間成形時に第２接着層１５にクラックが生じて白化することを抑制しやすく、濡れ性の改善による密着力の向上、異方性の低減による製膜性の向上等が期待できる。これらのエラストマーは酸変性ポリオレフィン系樹脂中にナノメートルオーダーで分散、相溶していることが好ましい。 The second adhesive layer 15 having a heat laminate structure preferably contains a styrene elastomer or an olefin elastomer. Thereby, it is easy to suppress that the second adhesive layer 15 is cracked and whitened at the time of cold forming, and it is expected that the adhesion is improved by improving the wettability and the film forming property is improved by reducing the anisotropy. . These elastomers are preferably dispersed and compatible with each other in the order of nanometers in the acid-modified polyolefin resin.
　熱ラミネート構成における第２接着層１５は、上述の接着成分を押出し装置で押し出すことで形成できる。接着成分のメルトフローレート（ＭＦＲ）は、２３０℃、２．１６ｋｇｆの条件において４～３０ｇ／１０分が好ましい。
　熱ラミネート構成における第２接着層１５の厚さは２～５０μｍが好ましい。 The second adhesive layer 15 in the thermal laminate configuration can be formed by extruding the above-described adhesive component with an extrusion device. The melt flow rate (MFR) of the adhesive component is preferably 4 to 30 g / 10 min under the conditions of 230 ° C. and 2.16 kgf.
The thickness of the second adhesive layer 15 in the heat laminate configuration is preferably 2 to 50 μm.
　ドライラミネート構成における第２接着層１５の接着成分としては、例えば、第１接着層１２で挙げた成分と同様の２液硬化型のポリウレタン系接着剤が挙げられる。
　ドライラミネート構成における第２接着層１５は、エステル基やウレタン基等の加水分解性の高い結合部を有している。そのため、より高い信頼性が求められる用途には熱ラミネート構成の第２接着層１５が好ましい。 As an adhesive component of the second adhesive layer 15 in the dry laminate configuration, for example, a two-component curable polyurethane adhesive similar to the component mentioned in the first adhesive layer 12 may be used.
The second adhesive layer 15 in the dry laminate configuration has a highly hydrolyzable bonding portion such as an ester group or a urethane group. Therefore, the second adhesive layer 15 having a heat laminate structure is preferable for applications that require higher reliability.
［シーラント層］
　シーラント層１６は、外装材１においてヒートシールによる封止性を付与する層である。シーラント層１６としては、ポリオレフィン系樹脂、又はポリオレフィン系樹脂に無水マレイン酸等の酸をグラフト変性させた酸変性ポリオレフィン系樹脂から形成される樹脂フィルムが挙げられる。
　ポリオレフィン系樹脂としては、例えば、低密度、中密度、高密度のポリエチレン；エチレン－αオレフィン共重合体；ホモポリプロピレン、ブロックポリプロピレン、又はランダムポリプロピレン；プロピレン－αオレフィン共重合体等が挙げられる。これらポリオレフィン系樹脂は、１種を単独で使用してもよく、２種以上を併用してもよい。
　酸変性ポリオレフィン系樹脂としては、例えば、第２接着層１５で挙げた樹脂と同じ種類が挙げられる。 [Sealant layer]
The sealant layer 16 is a layer that imparts sealing properties by heat sealing in the exterior material 1. Examples of the sealant layer 16 include a resin film formed from a polyolefin resin or an acid-modified polyolefin resin obtained by graft-modifying an acid such as maleic anhydride to a polyolefin resin.
Examples of the polyolefin resin include low density, medium density, and high density polyethylene; ethylene-α olefin copolymer; homopolypropylene, block polypropylene, or random polypropylene; propylene-α olefin copolymer. These polyolefin resin may be used individually by 1 type, and may use 2 or more types together.
Examples of the acid-modified polyolefin resin include the same type as the resin exemplified in the second adhesive layer 15.
　シーラント層１６は、単層フィルムでも多層フィルムでもよく、必要とされる機能に応じて選択すればよい。例えば、防湿性を付与する点では、エチレン－環状オレフィン共重合体やポリメチルペンテン等の樹脂を介在させた多層フィルムが使用できる。
　また、シーラント層１６は、難燃剤、スリップ剤、アンチブロッキング剤、酸化防止剤、光安定剤、粘着付与剤等の各種添加材が配合されてもよい。
　シーラント層１６の厚さは、１０～１００μｍが好ましく、２０～６０μｍがより好ましい。 The sealant layer 16 may be a single layer film or a multilayer film, and may be selected according to a required function. For example, in terms of imparting moisture resistance, a multilayer film in which a resin such as an ethylene-cycloolefin copolymer or polymethylpentene is interposed can be used.
The sealant layer 16 may be blended with various additives such as a flame retardant, slip agent, anti-blocking agent, antioxidant, light stabilizer, and tackifier.
The thickness of the sealant layer 16 is preferably 10 to 100 μm, and more preferably 20 to 60 μm.
　外装材１としては、ドライラミネーションによってシーラント層１６が積層された構成でもよい。しかしながら、接着性向上の点から、第２接着層１５が酸変性ポリオレフィン系樹脂から形成されるサンドイッチラミネーションによってシーラント層１６が積層されていることが好ましい。 The exterior material 1 may have a configuration in which a sealant layer 16 is laminated by dry lamination. However, from the viewpoint of improving adhesiveness, it is preferable that the sealant layer 16 is laminated by sandwich lamination in which the second adhesive layer 15 is formed from an acid-modified polyolefin resin.
［製造方法］
　以下、外装材１の製造方法について説明する。ただし、下記内容は一例であり、外装材１の製造方法は下記の内容に限定されない。
　外装材１の製造方法としては、例えば、下記工程（１）～（３）を有する方法が挙げられる。
　工程（１）：金属箔層１３上に、腐食防止処理層１４を形成する工程。
　工程（２）：金属箔層１３における腐食防止処理層１４を形成した面と反対側の面に、第１接着層１２を介して基材層１１をはり合わせる工程。
　工程（３）：金属箔層１３上に形成された腐食防止処理層１４に、第２接着層１５を介してシーラント層１６を貼り合わせる工程。 [Production method]
Hereinafter, the manufacturing method of the exterior material 1 is demonstrated. However, the following content is an example, and the manufacturing method of the exterior material 1 is not limited to the following content.
Examples of the manufacturing method of the packaging material 1 include a method having the following steps (1) to (3).
Step (1): A step of forming a corrosion prevention treatment layer 14 on the metal foil layer 13.
Step (2): A step of bonding the base material layer 11 through the first adhesive layer 12 to the surface of the metal foil layer 13 opposite to the surface on which the corrosion prevention treatment layer 14 is formed.
Step (3): A step of bonding the sealant layer 16 to the corrosion prevention treatment layer 14 formed on the metal foil layer 13 via the second adhesive layer 15.
（工程（１））
　金属箔層１３の一方の面（第１の面）に、腐食防止処理剤を塗布、乾燥して腐食防止処理層１４を形成する。腐食防止処理剤としては、例えば、前記したセリアゾール処理用の腐食防止処理剤、クロメート処理用の腐食防止処理剤等が挙げられる。
　腐食防止処理剤の塗布方法は特に限定されず、グラビアコート、リバースコート、ロールコート、バーコート等、各種方法を採用できる。 (Process (1))
A corrosion prevention treatment agent is applied to one surface (first surface) of the metal foil layer 13 and dried to form the corrosion prevention treatment layer 14. Examples of the anti-corrosion treatment agent include the above-described anti-corrosion treatment agent for ceriazole treatment, anti-corrosion treatment agent for chromate treatment, and the like.
The coating method of the corrosion inhibitor is not particularly limited, and various methods such as gravure coating, reverse coating, roll coating, and bar coating can be employed.
（工程（２））
　金属箔層１３における腐食防止処理層１４を形成した面と反対側の面（第２の面）に、第１接着層１２を形成する接着剤を用いて、ドライラミネーション等の手法で基材層１１を貼り合わせる。
　基材層１１を貼り合わせる際は、第１基材層１１ａと第１接着層１２とが接するよう貼り合わせる。
　工程（２）では、接着性の促進のため、室温～１００℃の範囲でエージング（養生）処理を行ってもよい。 (Process (2))
The base material layer is formed by a technique such as dry lamination using an adhesive for forming the first adhesive layer 12 on the surface (second surface) opposite to the surface on which the corrosion prevention treatment layer 14 is formed in the metal foil layer 13. 11 is pasted together.
When bonding the base material layer 11, it bonds so that the 1st base material layer 11a and the 1st contact bonding layer 12 may contact | connect.
In step (2), an aging treatment (curing) may be performed in the range of room temperature to 100 ° C. in order to promote adhesion.
（工程（３））
　基材層１１、第１接着層１２、金属箔層１３及び腐食防止処理層１４がこの順に積層された積層体の腐食防止処理層１４上に、押出ラミネート法によって第２接着層１５を形成し、シーラント層１６を形成する樹脂フィルムを貼り合わせる。シーラント層１６の積層は、サンドイッチラミネーションにより行うことが好ましい。 (Process (3))
A second adhesive layer 15 is formed by extrusion lamination on the corrosion prevention treatment layer 14 of the laminate in which the base material layer 11, the first adhesion layer 12, the metal foil layer 13, and the corrosion prevention treatment layer 14 are laminated in this order. Then, a resin film for forming the sealant layer 16 is bonded. The lamination of the sealant layer 16 is preferably performed by sandwich lamination.
　以上説明した工程（１）～（３）により、外装材１が得られる。
　なお、外装材１の製造方法の工程順序は、前記（１）～（３）を順次実施する方法に限定されない。例えば、工程（２）を行ってから工程（１）を行ってもよい。 The exterior material 1 is obtained by the steps (1) to (3) described above.
Note that the process sequence of the manufacturing method of the packaging material 1 is not limited to the method of sequentially performing the above (1) to (3). For example, step (1) may be performed after performing step (2).
　完成した外装材１を２枚用意してシーラント層１６どうしを対向させる、あるいは１枚の外装材１をシーラント層１６が対向するように折り返して、内部に発電要素や端子となるタブ部材等を配置し、周縁をヒートシールにより接合すると、外装材１を用いたリチウムイオン電池セルが完成する。
　以下、本実施形態の外装材１を用いたリチウムイオン電池の製造方法における外装材１の成型加工方法の一例について、図２および図３を参照して説明する。図２は、外装材１の平面図であり、図３は、図２のＩ－Ｉ線における断面図である。
　ここでは、リチウムイオン電池を製造する過程において外装材１に平面視矩形状をなす凹部として図２および図３に示す成型加工エリア１７を形成する成型加工方法を説明する。 Prepare two finished exterior materials 1 so that the sealant layers 16 face each other, or fold back one exterior material 1 so that the sealant layers 16 face each other, and a tab member or the like that becomes a power generation element or terminal is inside. If it arrange | positions and a periphery will be joined by heat sealing, the lithium ion battery cell using the exterior material 1 will be completed.
Hereinafter, an example of a method for molding the exterior material 1 in the method for manufacturing a lithium ion battery using the exterior material 1 of the present embodiment will be described with reference to FIGS. 2 and 3. FIG. 2 is a plan view of the packaging material 1, and FIG. 3 is a cross-sectional view taken along the line II of FIG.
Here, a molding method for forming the molding processing area 17 shown in FIGS. 2 and 3 as a concave portion having a rectangular shape in plan view in the exterior material 1 in the process of manufacturing a lithium ion battery will be described.
　成型加工エリア１７は、例えば矩形状の圧力面を有する押圧部材を外装材１の一部に対してその厚さ方向に押圧することで形成される。また、押圧する位置、すなわち成型加工エリア１７を、図２および図３に示すように、長方形に切り出した外装材１の中央より偏った位置に形成するのが好ましい。このようにすると、成型加工後に外装材１の成型加工エリア１７が形成されていない部分を折り返し、成型加工エリア１７に蓋をするように外装体を形成することができる。 The molding process area 17 is formed, for example, by pressing a pressing member having a rectangular pressure surface against a part of the exterior material 1 in the thickness direction. Moreover, it is preferable to form the pressing position, that is, the molding area 17 at a position deviated from the center of the exterior material 1 cut into a rectangle as shown in FIGS. If it does in this way, the part by which the molding process area 17 of the cladding | exterior_material 1 is not formed after a shaping | molding process will be return | folded, and an exterior body can be formed so that the molding process area 17 may be covered.
　このような成型加工を行った後、外装材１に以下の工程が施されることでリチウムイオン電池が製造される。
　即ち、上記工程のように凹部としての成型加工エリア１７を形成後、該凹部の内部に、正極、セパレータ、及び負極を入れる。その後、外装材１を折り返し、シーラント層が向かい合うように重ね合わせ、その二辺をヒートシールする。その後、真空状態において、残った一辺から電解液を注入し、残りの一辺をヒートシールして密封することでリチウムイオン電池が形成される。
　なお、本発明のリチウムイオン電池用外装材を使用したリチウムイオン電池は、前記方法で製造した構成には限定されない。例えば、外装材１を２枚用意し、シーラント層１６どうしを対向させて接合することによりリチウムイオン電池を形成してもよい。 After performing such a molding process, a lithium ion battery is manufactured by performing the following steps on the exterior material 1.
That is, after forming the molding process area 17 as a recess as in the above process, the positive electrode, the separator, and the negative electrode are placed inside the recess. Thereafter, the exterior material 1 is folded back and overlapped so that the sealant layers face each other, and the two sides are heat-sealed. Thereafter, in a vacuum state, an electrolyte is injected from the remaining side, and the remaining side is heat-sealed and sealed to form a lithium ion battery.
In addition, the lithium ion battery using the exterior material for lithium ion batteries of this invention is not limited to the structure manufactured by the said method. For example, a lithium ion battery may be formed by preparing two exterior members 1 and bonding the sealant layers 16 so as to face each other.
　以上説明したように、本実施形態の外装材１によれば、第１基材層１１ａをポリエステル樹脂、または、ポリアミド樹脂によって形成することで金属箔層１３を保護し、成型性を向上させることが可能となる。
　さらに、第２基材層１１ｂにポリエステルエラストマーが含有されていることで、成型加工後の外装材の反り量の低減を図ることが可能となる。 As described above, according to the packaging material 1 of the present embodiment, the metal foil layer 13 is protected and the moldability is improved by forming the first base material layer 11a with a polyester resin or a polyamide resin. Is possible.
Further, since the second base material layer 11b contains the polyester elastomer, it is possible to reduce the amount of warping of the exterior material after the molding process.
　また、第１基材層１１ａの厚さを４μｍ～２０μｍに設定し、第２基材層１１ｂの厚さを２μｍ～１５μｍに設定することで成型性を向上させたまま、成型加工後の外装材の反り量の低減を図ることが可能となる。 In addition, the thickness of the first base material layer 11a is set to 4 μm to 20 μm, and the thickness of the second base material layer 11b is set to 2 μm to 15 μm so that the moldability is improved and the exterior after molding is processed. It becomes possible to reduce the amount of warping of the material.
　さらに、基材層１１を共押出し法により形成することで、第１基材層１１ａおよび第２基材層１１ｂの薄膜化が可能となる。 Furthermore, by forming the base material layer 11 by the coextrusion method, the first base material layer 11a and the second base material layer 11b can be thinned.
　本発明の外装材および二次電池について、実施例および比較例を用いてさらに説明するが、本発明は、実施例の具体的内容にもとづいて何ら限定されない。
［使用材料］
　まず、実施例および比較例において使用した各層の材料を以下に示す。
（基材層）
　実施例１～７及び比較例１～５において用いた基材層の構成を表１に示す。 The packaging material and secondary battery of the present invention will be further described with reference to examples and comparative examples, but the present invention is not limited at all based on the specific contents of the examples.
[Materials used]
First, the material of each layer used in Examples and Comparative Examples is shown below.
(Base material layer)
Table 1 shows the structures of the base material layers used in Examples 1 to 7 and Comparative Examples 1 to 5.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　（第１接着層）
　接着剤Ｂ－１：ポリエステルウレタン系接着剤 (First adhesive layer)
Adhesive B-1: Polyester urethane adhesive
（金属箔層）
　金属箔Ｃ－１：軟質アルミニウム箔８０７９材（東洋アルミニウム社製、厚さ４０μｍ） (Metal foil layer)
Metal foil C-1: Soft aluminum foil 8079 (Toyo Aluminum Co., Ltd., thickness 40 μm)
（腐食防止処理層）
　処理剤Ｄ－１：酸化セリウム、リン酸、アクリル系樹脂を主体とした塗布型セリアゾール処理用の処理剤 (Corrosion prevention treatment layer)
Treatment agent D-1: Treatment agent for coating-type ceriazole treatment mainly composed of cerium oxide, phosphoric acid and acrylic resin
（第２接着層１５）
　接着樹脂Ｅ－１：無水マレイン酸でグラフト変性したポリプロピレン系樹脂（商品名「アドマー」、三井化学社製） (Second adhesive layer 15)
Adhesive resin E-1: Polypropylene resin graft-modified with maleic anhydride (trade name “Admer”, manufactured by Mitsui Chemicals, Inc.)
（シーラント層１６）
　フィルムＦ－１：無延伸ポリプロピレンフィルム（厚さ４０μｍ）の内面となる面をコロナ処理したフィルム (Sealant layer 16)
Film F-1: Film obtained by corona-treating the inner surface of an unstretched polypropylene film (thickness 40 μm)
［外装材の作成］
　金属箔層となる金属箔Ｃ－１の一方の面に処理剤Ｄ－１を塗布、乾燥して腐食防止処理層を形成した。次に、金属箔層の腐食防止処理層が形成された面と反対側の面に、接着剤Ｂ－１を用いたドライラミネート法により、基材Ａ－１～Ａ－１２のいずれか１つを貼り合せた。その後、６０℃、６日間のエージングを行った。次に、得られた積層体の腐食防止処理層上に押出し装置にて接着樹脂Ｅ－１を押出して第２接着層を形成し、フィルムＦ－１を貼り合わせてサンドイッチラミネーションすることでシーラント層を形成した。その後、得られた積層体に対し、１９０℃、４ｋｇ／ｃｍ２、２ｍ／分の条件で加熱圧着することで外装材を作成した。 [Creating exterior materials]
Treatment agent D-1 was applied to one surface of metal foil C-1 to be a metal foil layer and dried to form a corrosion prevention treatment layer. Next, any one of the substrates A-1 to A-12 is formed on the surface of the metal foil layer opposite to the surface on which the corrosion prevention treatment layer is formed by a dry laminating method using an adhesive B-1. Were pasted together. Thereafter, aging was performed at 60 ° C. for 6 days. Next, a second adhesive layer is formed by extruding the adhesive resin E-1 on the corrosion prevention treatment layer of the obtained laminate with an extruder, and the sealant layer is formed by laminating and bonding the film F-1. Formed. Then, the obtained laminate, 190 ° C., was created exterior material by heat pressing at 4kg / cm 2, 2m / min conditions.
［成型性の評価］
　各例で得られた外装材を、１５０ｍｍ×１９０ｍｍのブランク形状に切り取り、２３℃、４０％ＲＨ（相対湿度）の成形環境下で成形深さを変化させながら冷間成型し、成型性を評価した。
　パンチとしては、形状が１００ｍｍ×１５０ｍｍ、パンチコーナーＲ（ＲＣＰ）が１．５ｍｍ、パンチ肩Ｒ（ＲＰ）が０．７５ｍｍ、ダイ肩Ｒ（ＲＤ）が０．７５ｍｍであるパンチを使用した。評価基準は、以下に従って行った。
　Ｅ（excellent）：破断、クラックを生じさせずに、成型深さ６ｍｍ以上の深絞り成型が可能である。
　Ｆ（fair）：破断、クラックを生じさせずに、成型深さ４ｍｍ以上６ｍｍ未満の深絞り成型が可能である。
　Ｉ（insufficient）：成形深さ４ｍｍ未満の深絞り成型で破断、クラックが生じる。 [Evaluation of moldability]
The exterior material obtained in each example is cut into a blank shape of 150 mm × 190 mm, cold-molded while changing the molding depth in a molding environment of 23 ° C. and 40% RH (relative humidity), and the moldability is evaluated. did.
As the punch, a punch having a shape of 100 mm × 150 mm, a punch corner R (RCP) of 1.5 mm, a punch shoulder R (RP) of 0.75 mm, and a die shoulder R (RD) of 0.75 mm was used. Evaluation criteria were performed according to the following.
E (excellent): Deep drawing with a molding depth of 6 mm or more is possible without causing breakage and cracks.
F (fair): Deep drawing with a molding depth of 4 mm or more and less than 6 mm is possible without causing breakage or cracks.
I (insufficient): Breaking and cracking occur in deep drawing with a molding depth of less than 4 mm.
［成型加工後反り量の評価］
　各例で得られた外装材を、引張り評価で得られた引張伸度の大きい方向を長辺として１２０ｍｍ×２６０ｍｍのブランク形状に切り取り、２３℃、４０％ＲＨの成型環境下で成型深さ３ｍｍに設定し、冷間成型を行った。
　成型エリアはブランク形状端から２５ｍｍとし、ブランク形状の片側に寄せた状態で成型を行った。
　パンチとしては、形状が７０ｍｍ×８０ｍｍ、ＲＣＰが１．５ｍｍ、ＲＰが０．７５ｍｍ、ＲＤが０．７５ｍｍであるパンチを使用した。
　成型加工された外装材を、成形エリアの基材層側が上となるように平坦な基準面に固定し、成型加工から６０分後に成型されていないエリアの端辺の反り量（基準面からの距離）を測定した。評価基準は、以下に従って行った。
　Ｅ（excellent）：反り量が５０ｍｍ未満
　Ｆ（fair）：反り量が５０ｍｍ以上１００ｍｍ未満
　Ｉ（insufficient）：反り量が１００ｍｍ以上 [Evaluation of warpage after molding]
The exterior material obtained in each example was cut into a 120 mm × 260 mm blank shape with the long side of the tensile elongation obtained in the tensile evaluation as the long side, and the molding depth was 3 mm in a molding environment of 23 ° C. and 40% RH. And cold forming was performed.
The molding area was 25 mm from the end of the blank shape, and molding was performed in a state of being brought to one side of the blank shape.
As the punch, a punch having a shape of 70 mm × 80 mm, RCP of 1.5 mm, RP of 0.75 mm, and RD of 0.75 mm was used.
The molded exterior material is fixed to a flat reference surface so that the base material layer side of the molding area faces up, and the warping amount of the edge of the unmolded area after 60 minutes from the molding process (from the reference surface) Distance) was measured. Evaluation criteria were performed according to the following.
E (excellent): Warpage amount is less than 50 mm F (fair): Warpage amount is 50 mm or more and less than 100 mm I (insufficient): Warpage amount is 100 mm or more
　実施例１～７および比較例１～５の成型性および成型加工後反り量の評価結果を表２に示す。 Table 2 shows the evaluation results of moldability and post-molding warpage amount of Examples 1 to 7 and Comparative Examples 1 to 5.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　本発明の一実施形態に係る構成を有する実施例１～７では、十分な成型性が得られるとともに、成型加工後の反り量を低減できるリチウムイオン電池用外装材を提供することができた。 In Examples 1 to 7 having the configuration according to an embodiment of the present invention, it was possible to provide a packaging material for a lithium ion battery that can obtain sufficient moldability and can reduce the amount of warping after molding.
　以上、本発明の各実施形態および実施例について説明したが、本発明の技術範囲は上記実施形態に限定されず、本発明の趣旨を逸脱しない範囲において構成要素の組合せを変えたり、各構成要素に種々の変更を加えたり、削除したりすることが可能である。 The embodiments and examples of the present invention have been described above. However, the technical scope of the present invention is not limited to the above-described embodiments, and the combinations of the components may be changed without departing from the spirit of the present invention. It is possible to make various changes to or delete them.
１　リチウムイオン電池用外装材
１１　基材層
１１ａ　第１基材層
１１ｂ　第２基材層
１２　第１接着層
１３　金属箔層
１４　腐食防止処理層
１５　第２接着層
１６　シーラント層 DESCRIPTION OF SYMBOLS 1 Lithium ion battery exterior material 11 Base material layer 11a 1st base material layer 11b 2nd base material layer 12 1st contact bonding layer 13 Metal foil layer 14 Corrosion prevention processing layer 15 2nd contact bonding layer 16 Sealant layer

Claims (3)

  1. 　ポリエステル樹脂またはポリアミド樹脂で形成された第１基材層と、ポリエステルエラストマーを含有し、前記第１基材層上に形成された第２基材層と、を有する基材層と、
    　前記第１基材層上に積層された第１接着層と、
    　前記第１接着層上に積層された金属箔層と、
    　前記金属箔層上に積層された腐食防止処理層と、
    　前記腐食防止処理層上に形成された第２接着層と、
    　前記第２接着層上に形成されたシーラント層と、を有するリチウムイオン電池用外装材。     A base material layer having a first base material layer formed of a polyester resin or a polyamide resin and a second base material layer containing a polyester elastomer and formed on the first base material layer;
    A first adhesive layer laminated on the first base material layer;
    A metal foil layer laminated on the first adhesive layer;
    A corrosion prevention treatment layer laminated on the metal foil layer;
    A second adhesive layer formed on the corrosion prevention treatment layer;
    And a sealant layer formed on the second adhesive layer.
  2. 　前記第１基材層の厚さが４μｍ以上２０μｍ以下であり、
    　前記第２基材層の厚さが２μｍ以上１５μｍ以下であり、
    　前記基材層の厚さが６μｍ以上、２５μｍ以下である、請求項１に記載のリチウムイオン電池用外装材。     The thickness of the first base material layer is 4 μm or more and 20 μm or less,
    The thickness of the second base material layer is 2 μm or more and 15 μm or less,
    The exterior material for a lithium ion battery according to claim 1, wherein the thickness of the base material layer is 6 µm or more and 25 µm or less.
  3. 　前記基材層が共押出し法で形成される、請求項１または請求項２に記載のリチウムイオン電池用外装材。 The exterior material for a lithium ion battery according to claim 1 or 2, wherein the base material layer is formed by a coextrusion method.
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