JP5414832B2 - Method for producing composite packaging material for polymer battery - Google Patents

Description

  The present invention relates to a composite packaging material for a polymer battery, and more particularly to a method for producing a composite packaging material for a polymer battery comprising a composite aluminum foil.

Polymer batteries are lithium-ion secondary batteries used as power sources for electronic devices such as mobile phones, notebook computers, and video cameras. Polymer batteries use solid or semi-solid electrolytes such as conductive polymers. The electrolyte is a non-aqueous solvent such as PC (propylene carbonate), DEC (diethylene carbonate), EC (ethylene carbonate), and γ-BL (gamma butyrolactone), and complex fluorides such as LiBF ₄ and LiPF _6. Compared to ordinary lithium-ion secondary batteries that use a battery with the addition of lithium ion, it is possible to achieve thinner and lighter weight, and there is less risk of electrolyte leakage etc. The future development is expected.

As a polymer battery case, conventionally, a battery formed by heat sealing a packaging material formed from a composite aluminum foil obtained by bonding a thermoplastic resin such as polypropylene to an aluminum foil by heat lamination is used. Since a material containing a solvent such as PC, DEC, EC, or γ-BL to which a complex fluoride such as LiBF ₄ or LiPF ₆ is added is used, a part of the complex fluoride in the solvent is used as an electrode or a packaging material. Hydrofluoric acid (HF) generated by reacting with water adsorbed on the surface penetrates the heat-sealable thermoplastic resin layer to reach the surface of the aluminum foil and corrodes the aluminum foil. Adhesiveness with a plastic resin layer falls and it may lead to peeling of a thermoplastic resin layer.

  In order to solve the above problems, some of the inventors have previously proposed a packaging material for a polymer battery comprising a composite aluminum foil laminated in the order of an aluminum foil, a maleated PP layer and an extrusion-coated polypropylene layer. (Japanese Patent Application No. 11-275827). According to this packaging material, by interposing maleated PP between the aluminum foil and the thermoplastic resin layer, the electrolytic solution resistance and the solvent resistance are improved, and the aluminum foil by permeation of hydrofluoric acid and Although the decrease in adhesion with the thermoplastic resin layer can be reduced, depending on the use conditions, the electrolytic solution resistance and the solvent resistance may not be sufficient, and between the aluminum foil and the thermoplastic resin layer. It has been experienced that peeling occurs due to a decrease in adhesion.

  The present invention is based on the polymer electrode packaging material described in Japanese Patent Application No. 11-275827 and is used for polymer batteries in order to solve the above-mentioned problems in the polymer electrode packaging material comprising a composite aluminum foil. It was made as a result of reexamination of the characteristics required for packaging materials, especially the anti-electrolyte properties, the solvent resistance and the adhesion between the layers of the composite aluminum foil. For polymer batteries that have liquid properties and solvent resistance, and that do not peel off the aluminum foil and thermoplastic resin layer even when they come into contact with the electrolyte, and have excellent heat sealability, adhesion to electrode terminals, and adhesion It is providing the manufacturing method of a composite packaging material.

In order to achieve the above object, a method for producing a composite packaging material for a polymer battery according to the present invention comprises a coating type surface treating agent comprising a metal salt of one of zirconium, titanium and silicon on the surface of an aluminum foil. The surface treatment layer in which one kind of metal of zirconium, titanium, and silicon is adhered to the surface of the aluminum foil is formed by treating with heat drying, and the metal adhered to the surface of the aluminum foil is formed. The amount of adhesion was set to 1 to 100 mg / m ^2, and maleic anhydride-modified polypropylene (maleated PP, hereinafter the same) was applied to the surface of the aluminum foil on which the surface treatment layer was formed by a gravure coating method or a roll coating method. A maleated PP layer is formed by coating at a coating amount of 10 g / m ^{2, and} a thermoplastic resin layer is laminated on the maleated PP layer.

  According to the present invention, the aluminum foil and the thermoplastic resin layer do not peel off even when in contact with the electrolytic solution, with excellent electrolytic solution resistance and solvent resistance. A method for producing a polymer battery composite packaging material having excellent adhesion and adhesion is provided.

It is sectional drawing which shows one Example of the composite packaging material for polymer batteries manufactured by this invention.

  In the composite packaging material for a polymer battery manufactured according to the present invention, as shown in FIG. 1, a composite aluminum foil in which an aluminum foil 3, a maleated PP layer 4, and a thermoplastic resin layer 5 are laminated in this order, The composite packaging material 1 is constituted by the composite aluminum foil 2 in which the foil 3 and the maleated PP are bonded via a surface treatment layer 6 containing one kind of metal of zirconium, titanium, and silicon.

  As the aluminum foil 3, tempered O to H18 such as a pure aluminum-based aluminum foil (JIS H4160 1N30 or the like) having a thickness of 6 to 300 μm, an Al—Fe alloy foil, or the like is used.

  The surface treatment layer 6 formed on the surface of the aluminum foil 3 is obtained by treating the surface of the aluminum foil with a coating-type surface treatment agent containing a metal salt of one of zirconium, titanium, and silicon. . The coating type surface treatment agent is prepared by combining a reducing agent, an inorganic acid, an organic compound, and the like in addition to the metal salt.

Zirconium, titanium, silicon fluoride salts (ZrF ₄ ²⁻ , TiF ₆ ²⁻ , SiF ₆ ²⁻ ), silicates, etc. are used as metal salts, and alcohols, polysaccharides are used as reducing agents. Organic compounds having a hydroxyl group such as tannic acid, methanol, hydrazine, sucrose, etc., inorganic acids such as phosphoric acid, hydrofluoric acid, silicic acid, etc., organic compounds such as polyacrylic acid, polymethacrylic acid, Examples include acrylic acid and methacrylic acid copolymers, cellulose, and polyvinyl alcohol. In order to improve the corrosion resistance, silica particles such as vapor phase silica and colloidal silica may be contained.

The maleated PP layer 4 laminated on the surface of the aluminum foil via the surface treatment layer plays a role of electrolytic solution resistance and solvent resistance. The coating of the maleated PP on the aluminum foil 3 surface is as follows. It is carried out by applying maleated PP dissolved or dispersed in an aromatic organic solvent such as toluene or xylene on the surface of the aluminum foil. As a coating method, a gravure coating method is preferable from the viewpoint of mass productivity, but a roll coating method is also applied. The coating amount is preferably 0.2 to 10 g / m ^{2. When the} coating amount is less than 0.2 g / m ² , it is difficult to apply uniformly. When the coating amount exceeds 10 g / m ² , the effect of improving the adhesion is saturated. Therefore, coating exceeding 10 g / m ² is economically disadvantageous.

  Lamination of the thermoplastic resin layer 5 to the maleated PP layer 4 is performed by thermocompression bonding of a film of polyethylene, polypropylene, ionomer resin or the like by a thermal laminating method, or a film is formed by extruding a molten resin from a die. The extrusion coating method is performed. The thermoplastic resin layer 5 is excellent in heat-resistant heat sealability and adhesion to electrode terminals, and wraps the polymer electrolyte composite packaging material 1 with a solid electrolyte and electrodes, and heat-seals the packaging material including the electrode terminals. Serves as a heat seal layer. The thermoplastic resin layer 5 is preferably formed with a thickness of 15 to 100 μm.

  In the polymer battery composite packaging material, a heat-resistant biaxially stretched film layer (for example, a thickness of 6 to 100 μm) of a thermoplastic resin such as a nylon film or a polyethylene terephthalate film on the surface of the aluminum foil 3 (outside of the battery), You may form by dry-laminating with adhesives, such as a urethane type adhesive agent, and puncture resistance can be improved by formation of a thermoplastic resin film.

  The production of the polymer battery composite packaging material of the present invention will be described. First, the aluminum foil is degreased, washed, and ground-treated as necessary, and then the coating-type surface treatment agent prepared as described above is rolled. Apply the gravure coating method. The coating temperature is not particularly limited, but it is preferably performed at a temperature of room temperature to 40 ° C. After the application, the aluminum foil is heated and dried so that the maximum temperature of the aluminum foil reaches a temperature of 60 to 250 ° C. If it is less than 60 ° C., a sufficient film cannot be formed, and if it exceeds 250 ° C., a sufficient adhesion imparting effect cannot be obtained.

By treating the surface of the aluminum foil with a coating type surface treating agent containing a metal salt of one of the metals of zirconium, titanium and silicon, the surface of the aluminum foil is made of one of zirconium, titanium and silicon. Although the surface treatment layer to which the metal has adhered is formed, it is preferable to select the coating amount so that the adhesion amount of the metal adhering to the surface of the aluminum foil is 1 to 100 mg / m ² after the treatment. If it is less than 1 mg / m ² , sufficient adhesion cannot be obtained, and if it exceeds 100 mg / m ² , the effect of improving adhesion is saturated, so that application exceeding 100 mg / m ² is economically disadvantageous.

  A coating agent in which maleated PP particles are dissolved or dispersed is prepared, and maleated PP is applied by the gravure coating method as described above, and dried at a temperature of about 180 to 250 ° C. for about 5 to 10 seconds. Then, the maleated PP layer 4 is formed on the surface of the aluminum foil via the surface treatment layer.

  Next, a thermoplastic resin is formed by forming a film of polyethylene, polypropylene, ionomer resin or the like on the maleated PP layer 4 by thermocompression bonding using a heat laminating method or by extruding a molten resin from a die using an extrusion coating method. Layer 5 is laminated.

  If necessary, a thermoplastic resin film such as a nylon film or a polyethylene terephthalate film is dry-laminated on the outer surface (outside of the battery) of the aluminum foil 3 with an urethane adhesive as necessary. .

  When the polymer battery composite packaging material produced according to the present invention is used as a packaging material for a polymer battery, electrode terminals in which a maleated PP layer is coated on both surfaces of an electrode plate made of Al, Cu or Ni are applied. It is preferable that the electrolyte is sandwiched between the composite packaging materials manufactured according to the present invention, and the electrode terminals are heat-sealed with the composite packaging materials. With this configuration, the adhesive strength between the composite packaging material and the electrode terminals in the heat seal portion is increased. be able to.

  Examples of the present invention will be described below in comparison with comparative examples. In addition, a present Example is for describing one preferable embodiment of this invention, Comprising: This invention is not restrict | limited by this.

Example 1
A coating type surface treatment agent is applied to one surface (glossy surface) of an aluminum foil (JIS H4160, 8021, tempered O material, thickness 50 μm) by a roll coating method, heated at 200 ° C. for 1 minute, and dried. By doing so, a surface treatment layer was formed. Table 1 shows the types of coating-type surface treatment agents (containing metals) and the amount of the metal attached.

Next, the maleated PP was applied by a roll coating method through the surface treatment layer so that the dry coating amount was 1 g / m ² and dried at 200 ° C. for 30 seconds to form a maleated PP layer. A polypropylene film (thickness 40 μm) was laminated on the maleated PP layer by thermocompression bonding to obtain a composite aluminum foil.

The obtained composite aluminum foil (test material) was cut into strips having a width of 15 mm to produce adhesion test pieces. As an electrolytic solution, a solution obtained by dissolving 1 mol / liter of LiPF ₆ in a mixed solvent of EC and DEC (a mixing ratio of EC: DEC = 1: 1 by volume) was used. The adhesion test piece was immersed in an electrolytic solution at 60 ° C., and the number of days until the aluminum foil and the polypropylene film layer were peeled was investigated. The results are shown in Table 1.

  As can be seen from Table 1, according to the composite packaging material comprising the composite aluminum foil according to the present invention, the adhesive between the aluminum foil and the maleated PP is good, and peeling is difficult to occur. It was recognized that it had characteristics and solvent resistance.

Comparative Example 1
A coating type surface treatment agent is applied to one surface (glossy surface) of an aluminum foil (JIS H4160, 8021, tempered O material, thickness 50 μm) by a roll coating method, heated at 200 ° C. for 1 minute, and dried. By doing so, a surface treatment layer was formed. Table 2 shows the types of coating-type surface treatment agents (containing metals) and the amount of the metal attached.

Next, the maleated PP was applied by a roll coating method through the surface treatment layer so that the dry coating amount was 1 g / m ² and dried at 200 ° C. for 30 seconds to form a maleated PP layer. A polypropylene film (thickness 40 μm) was laminated on the maleated PP layer by thermocompression bonding to obtain a composite aluminum foil.

  The obtained composite aluminum foil (test material) was cut into 15 mm-wide strips to produce adhesion test pieces. The same electrolyte solution as in Example 1 was used, and the adhesion test piece was immersed in an electrolyte solution at 60 ° C. Then, the number of days until the aluminum foil and the polypropylene film layer were peeled was investigated. The results are shown in Table 2.

  As shown in Table 2, all of the adhesion test pieces collected from the test materials that deviated from the conditions of the present invention were peeled off in a short period of time.

DESCRIPTION OF SYMBOLS 1 Composite packaging material for polymer batteries 2 Composite aluminum foil 3 Aluminum foil 4 Maleated PP layer 5 Thermoplastic resin layer 6 Surface treatment layer by coating type surface treatment agent

Claims (1)

The surface of the aluminum foil is treated with a coating-type surface treatment agent containing a metal salt of one of the metals of zirconium, titanium, and silicon, and dried by heating, whereby the surface of the aluminum foil is made of zirconium, titanium, and silicon. The surface treatment layer to which one kind of metal was attached was formed, the amount of the metal attached to the surface of the aluminum foil was set to 1 to 100 mg / m ^2, and then the aluminum foil having the surface treatment layer formed thereon maleic anhydride modified polypropylene to the surface (maleated PP, hereinafter) was applied at a coverage of from 0.2 to 10 g / m ² by a gravure coating method or roll coating method to form a maleated PP layer, maleated PP A method for producing a composite packaging material for a polymer battery, wherein a thermoplastic resin layer is laminated on the layer.

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