JP2007257952A - Packaging material for battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a packaging material for a battery with suitability in press molding and excellent in adhesiveness and contactness to an adhesive seal. <P>SOLUTION: The packaging material, at least provided with a base material layer 12, a barrier layer made of a metal foil, and a polyolefin system resin layer 14 with a heat-sealing property as an innermost layer, is also provided with a slip layer 11 made by almost uniformly applying a slipping agent on a whole surface of the base material layer at a given interval. An application area of the slipping agent is to be within the range of 5% or more and 30% or less of the whole surface area of the base layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a battery packaging material that exhibits stable sealing properties, moisture resistance, and moldability with the packaging material.

The lithium ion battery is also referred to as a lithium secondary battery, and includes a battery having a liquid, gel-like, and polymer-like electrolyte, and a positive electrode / negative electrode active material made of a polymer. In this lithium ion battery, the lithium atom (Li) in the lithium transition metal oxide, which is the positive electrode active material, is charged as lithium ion (Li ⁺ ) during charging and enters the carbon layer of the negative electrode (intercalation). This is a battery in which charge / discharge reaction proceeds when ions (Li ⁺ ) are separated from the carbon layer (deintercalation) and move to the positive electrode to become the original lithium compound. From the nickel-cadmium battery and the nickel-hydrogen battery The output voltage is high, the energy density is high, and the apparent discharge capacity is reduced by repeating shallow discharge and recharging, so that there is no so-called memory effect. Therefore, in recent years, it has been widely used as a power source for portable devices such as mobile phones, notebook computers, digital cameras, and small video cameras.

  The composition of the lithium ion battery is as follows: positive electrode current collector (aluminum, nickel) / positive electrode active material layer (polymeric positive electrode material such as metal oxide, carbon black, metal sulfide, electrolyte, polyacrylonitrile) / electrolyte layer (propylene carbonate) , Carbonate electrolytes such as ethylene carbonate, dimethyl carbonate, ethylene methyl carbonate, inorganic solid electrolytes composed of lithium salts, gel electrolytes, etc.) / Anode active material layers (lithium metals, alloys, carbon, electrolytes, polyacrylonitrile, etc.) Molecular negative electrode material) / negative electrode current collector (copper, nickel, stainless steel) and an outer package for packaging them. As the exterior body, conventionally, a metal can obtained by pressing a metal into a cylindrical shape or a rectangular parallelepiped shape has been used.

  However, in the conventional metal can, since the outer wall of the container is rigid, the shape of the battery itself is determined. For this reason, since the hardware side is designed in accordance with the battery, the size of the hardware using the battery is determined by the battery, and there is no degree of freedom in shape.

  Therefore, in recent years, there is a tendency to use an exterior body (hereinafter referred to as an exterior body) made of a laminated body having a high degree of freedom in shape. The material structure of the exterior body is composed of at least a base material layer in the outermost layer, a barrier layer, a heat seal layer in the innermost layer, and an adhesive layer for adhering the respective layers, in view of necessary physical properties, workability, economy and the like as a battery. Further, there is a pouch type in which a pouch is formed from the exterior body configured as described above and the lithium ion battery main body is accommodated, or an embossed type in which the exterior body is pressed to form a recess and the lithium ion battery main body is accommodated in the recess. Has been developed.

FIG. 7 shows the structure of a male type 21 and female type 22 press machine showing molding in an embossed type. 7A is a perspective view of the outer package 10 before pressing, FIG. 7B is a perspective view of the outer package molded into a concave shape after pressing, and FIG. 7C is a cross-sectional view taken along line X ₂ -X ₂ . FIG. 7D is an enlarged view of the Y ₁ portion.

  Here, in the case of the embossed type exterior body 10, as shown in FIG. 7A or FIG. 7B, it is necessary to form a recess for housing the lithium ion battery body by press molding or the like. FIG. 8A shows a single-sided embossed type. FIGS. 8B and 8C are both double-sided embossed types, but are different in peripheral seals and show a four-side seal and a three-side seal. Then, as shown in FIGS. 8D and 8E, the lithium ion battery 1 houses the lithium ion battery body 3 in the recess 7 formed in the exterior body body and covers the exterior body lid 5t. The peripheral seal portion 9 is completed by heat sealing. At this time, it is desirable that the side wall portion 8 to be molded is raised as much as possible so that the battery body is tightly accommodated.

  Further, as shown in FIG. 7, in the press molding, the concave portion is formed by pressing the base layer side of the planar outer package against the female mold 22 and pressing with the male mold 21 from the heat seal layer side. As a result, the exterior body 10 is formed with a heat seal layer on the inside of the recess for housing the battery body and a base material layer on the outside of the recess. However, if the slidability between the female die 22 and the base material layer is poor, a flaw due to a slip failure occurs in the outer casing 10 during pressing, and in an extreme case, pinholes and cracks occur in the barrier layer made of metal foil. Sometimes. Further, delamination may occur in a portion where the lithium ion battery main body is housed in an exterior body and the periphery thereof is heat sealed. Therefore, the appropriateness of the outer package 10 when pressing into a concave shape is important.

Conventionally, in order to solve this problem, the entire surface of the base material layer is coated with a slip agent such as a fatty acid amide to improve the slipperiness of the surface of the base material layer (see Patent Document 1).
JP 2002-216713 A

  However, since a lithium battery enclosed in a laminated outer package has lower impact resistance or the like than a lithium battery constituted by a metal can, it is usually used by being housed in a plastic case. At this time, in the plastic case, the lithium battery is fixed to the surface of the base material layer of the exterior body with an adhesive label. When the resin layer is coated, the moldability at the time of pressing is improved, but sufficient adhesion and adhesion between the exterior body and the pressure-sensitive adhesive label cannot be obtained, and the lithium battery cannot be fixed and adhered in the plastic case. . For this reason, the lithium battery hits the inner wall of the plastic case due to a drop impact or the like, and pinholes or cracks in the exterior body may occur.

  Then, in view of the said problem, this invention aims at providing the packaging material for batteries which has the aptitude in press molding and is excellent in adhesiveness and adhesiveness with an adhesive label.

  In order to achieve the above object, a first configuration of the present invention is a battery including at least an outermost base material layer, a barrier layer made of a metal foil, and an innermost heat-sealing polyolefin resin layer. In the packaging material, a slip layer is provided on the entire surface of the base material layer by applying the slip agent substantially uniformly at a predetermined interval, and the application area of the slip agent is 5 of the entire surface area of the base material layer. The battery packaging material is characterized by being in the range of not less than 30% and not more than 30%.

  The battery packaging material of the second configuration of the present invention is characterized in that the intervals between the application parts and the non-application parts of the slip agent are 0.1 mm or more and 5.0 mm or less, respectively.

  The battery packaging material of the third configuration of the present invention is characterized in that the application part and the non-application part are formed in a pattern that repeats alternately.

  The battery packaging material according to a fourth configuration of the present invention is characterized in that the slip agent contains a polydimethylsiloxane-based block copolymer.

  According to the first configuration of the present invention, by suppressing the application area of the slip agent to 5% or more and 30% or less of the entire surface of the base material layer, the application part of the slip agent ensures the slipperiness of the base material layer surface, At the time of pressing, it is possible to prevent generation of wrinkles due to poor sliding, pinholes and cracks in the barrier layer on the exterior body formed with the recesses. Further, the non-coated portion of the slip agent ensures a certain adhesion and adhesion with an adhesive seal such as an adhesive label, and can be stably adhered and fixed to a plastic case or the like.

  According to the second configuration of the present invention, the distance between the application parts of the slip agent and the interval between the non-application parts is 0.1 or more and 5.0 mm or less, respectively, in the limited slip agent coating area. An application part and a non-application part can be arrange | positioned at the whole base-material layer surface. Thereby, the slipperiness of the whole base-material layer surface is securable.

  According to the third configuration of the present invention, the entire surface of the base material layer is uniformly covered with the application part and the non-application part of the slip agent by forming the application part and the non-application part into a pattern that repeats continuously. Therefore, unevenness in slipperiness and adhesiveness on the entire surface of the base material layer is eliminated, and defective molding can be reduced in the embossing molding process to further increase productivity. Further, by changing the design of the pattern shape, it is possible to adjust the slipperiness and the adhesiveness in accordance with the shape of the mold.

  According to the 4th structure of this invention, while using the slip agent containing a polydimethyl silosan type | system | group block copolymer, while being able to ensure the slipperiness at the time of a process, the fatty acid amide type slip agent used conventionally Thus, the problem that the slip agent accumulates in the press machine and adheres to the exterior body can be solved.

  The present invention is a packaging material for a lithium ion battery that is excellent in moisture resistance and content resistance and has good productivity in emboss molding and the like. The exterior body will be described in more detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the part which is common in FIG. 7, FIG. 8 of a prior art example, and description is abbreviate | omitted.

  The material which comprises each layer of the packaging material for batteries of this invention is demonstrated with reference to FIG. The outer package according to the present invention has a base material layer 12 as an outermost layer, a heat seal layer 14 made of a polyolefin resin as an innermost layer, and a barrier layer 13 made of a metal foil therebetween. Further, a slip layer 11 is provided on the surface of the base material layer 12.

  Here, the base material layer 12 needs to have a spreadability that can withstand a press during embossing. Generally, it consists of a stretched polyester or nylon film. At this time, examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolymerized polyester, and polycarbonate. Examples of nylon include polyamide resin, that is, nylon 6, nylon 6,6, a copolymer of nylon 6 and nylon 6,6, nylon 6,10, polymetaxylylene adipamide (MXD6), and the like.

In addition, the base material layer 12 can be laminated in addition to the nylon film in order to improve the pinhole resistance and the insulation when used as a battery outer package. When making the base material layer 12 into a laminated body, a base material layer contains at least 1 resin layer of 2 or more layers, and the thickness of each layer is 6 micrometers or more, Preferably, it is 12-25 micrometers. Examples of laminating the base material layer include the following 1) to 7) although not shown.
1) Stretched polyethylene terephthalate / stretched nylon 2) Stretched nylon / stretched stretched polyethylene terephthalate In addition, packaging material mechanical suitability (transport stability in packaging machines and processing machines), surface protection (heat resistance, electrolyte resistance) ) When making the exterior body for a lithium ion battery as an embossed type as a secondary processing, the base material layer is used for the purpose of reducing the frictional resistance between the mold and the base material layer at the time of embossing or when an electrolytic solution adheres. In order to protect the substrate, it is preferable that the base material layer is multilayered, and the surface of the base material layer is provided with a fluorine resin layer, an acrylic resin layer, a silicone resin layer, a polyester resin layer, and a blended material layer thereof. .
3) Fluorine resin / stretched polyethylene terephthalate (Fluorine resin is a film or formed by drying after liquid coating)
4) Silicone resin / stretched polyethylene terephthalate (silicone resin is a film or formed by drying after liquid coating)
5) Fluorine-based resin / stretched polyethylene terephthalate / stretched nylon 6) Silicone-based resin / stretched polyethylene terephthalate / stretched nylon 7) Acrylic resin / stretched nylon (Acrylic resin is cured in a film or liquid coating and dried)

  The barrier layer 13 is a layer for preventing water vapor from entering the inside of the lithium ion battery from the outside, and stabilizes the pinhole property and processability (pouching, embossing formability) of the barrier layer alone, In addition, in order to have pinhole resistance, a metal such as aluminum or nickel having a thickness of 15 μm or more, or a film on which an inorganic compound such as silicon oxide or alumina is deposited may be used. Is 20 to 80 μm aluminum.

  In order to further improve the generation of pinholes and make the outer body type of the lithium ion battery an embossed type, in order to prevent the occurrence of cracks in the embossing molding, the material of the aluminum used as the barrier layer 13 is: By making the iron content 0.3 to 9.0% by weight, preferably 0.7 to 2.0% by weight, the aluminum has good extensibility compared with aluminum not containing iron, and the exterior The generation of pinholes due to bending as a body is reduced, and the side wall can be easily formed when the embossed type exterior body is molded. When the iron content is less than 0.3% by weight, effects such as prevention of pinholes and improvement of embossing formability are not observed, and the iron content of the aluminum exceeds 9.0% by weight. In this case, the flexibility as aluminum is hindered, and the bag-making property as an exterior body is deteriorated.

  In addition, aluminum produced by cold rolling changes its flexibility, waist strength and hardness under annealing (so-called annealing treatment) conditions, but the aluminum used in the present invention is harder than the non-annealed hard-treated product. Aluminum which tends to be soft with some or complete annealing is preferred. The degree of flexibility, waist strength, and hardness of aluminum, that is, the conditions for annealing, may be appropriately selected in accordance with processability (pouching, embossing). For example, in order to prevent wrinkles and pinholes at the time of emboss molding, annealed soft aluminum according to the degree of molding can be used.

  Moreover, the adhesive strength with the adhesive 15 improves by performing the chemical conversion treatment 13a on the front and back surfaces of the aluminum that is the barrier layer 13. The chemical conversion treatment 13a specifically refers to delamination between aluminum and the base material layer 12 during embossing by forming an acid-resistant film such as phosphate, chromate, fluoride, triazine thiol compound, etc. And hydrogen fluoride produced by the reaction between the electrolyte and water in the lithium ion battery prevents the aluminum surface from being dissolved and corroded, especially the aluminum oxide present on the aluminum surface from being dissolved and corroded. Improves surface adhesion (wetting), prevents delamination between the base material layer 12 and aluminum during embossing and heat sealing, and on the inner surface of the aluminum due to hydrogen fluoride generated by the reaction between electrolyte and moisture Delamination prevention effect is obtained.

  As a result of applying chemical conversion treatment 13a to the aluminum surface using various substances and studying the effect thereof, among the acid-resistant film-forming substances, from the three components of phenol resin, chromium fluoride (3) compound and phosphoric acid. It has been found that the phosphate chromate treatment using the constructed one is good. Further, a chemical conversion treatment agent containing a metal such as molybdenum, titanium, zircon, or a metal salt in a resin component containing at least a phenol resin is favorable.

  When the acid-modified polypropylene resin and the heat seal layer 14 (polypropylene film) are laminated on the chemical conversion treatment layer 13a by the sandwich lamination method or the coextrusion method, the extruded acid-modified polypropylene resin on the chemical conversion treatment surface The adhesiveness is poor, and as a countermeasure against this, an acid-modified polypropylene emulsion solution is applied to the chemical conversion surface 13a by a roll coating method, etc., dried, baked at a temperature of 170 to 200 ° C., and then co-extruded. Thus, it has been confirmed that the adhesive strength of the laminate is improved. However, the baking speed is extremely slow and the productivity is poor.

  Therefore, as a laminating method showing stable adhesive strength even without application or baking of acid-modified polypropylene, the base layer 12 and one side of the barrier layer 13 chemically treated on both sides are dry laminated, By laminating a polyolefin film as the heat seal layer 14 on the surface by a dry laminating method, a laminate having a predetermined adhesive strength can be obtained.

  In addition to the base material layer 12, the barrier layer 13, the adhesive layer 15, and the heat seal layer 14 (polypropylene or polyethylene), between the barrier layer 13 and the heat seal layer 14, 2 such as polyimide and polyethylene terephthalate are used. An intermediate layer made of an axially stretched film or the like may be provided. An intermediate | middle layer can prevent the short circuit by contact with the tab and barrier layer at the time of the heat | fever seal of the lithium ion battery exterior body at the time of the heat improvement of a lithium ion battery exterior body by improving the strength as a packaging material for lithium ion batteries.

  In addition, for each of the above layers, corona treatment, blast treatment, and oxidation treatment are appropriately performed for the purpose of improving and stabilizing film forming properties, lamination processing, and final product secondary processing (pouching, embossing). Surface activation treatment such as ozone treatment may be performed.

  The resin for forming the heat seal layer 14 is a polyolefin resin, that is, a single-layer film formed from a resin such as random propylene, homopropylene, or block propylene, or a film formed from a resin blended with the above resin. The single layer film made is used as a multilayer film. Random propylene is preferably used as the heat seal layer 14. Alternatively, it can also be used as a single layer or multilayer film composed of a linear low density polyethylene, a medium density polyethylene single layer or multilayer, or a linear low density polyethylene, medium density polyethylene blend resin.

  For each type of polypropylene, that is, random propylene, homopropylene, block propylene, and linear low density polyethylene, medium density polyethylene, low crystalline ethylene-butene copolymer, low crystalline propylene-butene copolymer, A terpolymer composed of a three-component copolymer of ethylene, butene, and propylene, silica, zeolite, an antiblocking agent (AB agent) such as acrylic resin beads, a fatty acid amide slip agent, and the like may be added.

A butene component, a terpolymer component comprising a three-component copolymer of ethylene, butene and propylene, a low crystalline ethylene and butene copolymer having a density of 900 kg / m ³ , an amorphous ethylene and propylene copolymer, A propylene-α / olefin copolymer component may be added.

As the heat seal layer 14, it is preferable to use the above-mentioned random polypropylene, which has good heat sealability between random polypropylenes, heat seal of packaging materials for lithium ion batteries such as moisture resistance and heat resistance. It has the required protective properties as the layer 14, and also has good laminating properties and embossing properties. The random polypropylene used for the heat seal layer 14 is preferably (1) a density of 0.90 g / cm ³ or more, a bigat softening point of 115 ° C. or more, and a melting point of 120 ° C. or more. The linear low density polyethylene or medium density polyethylene used for the heat seal layer 14 is preferably (1) a density of 0.91 g / cm ³ or more, a bigat softening point of 70 ° C. or more, and a melting point of 110 ° C. or more.

  The random polypropylene may be a general random polypropylene having an ethylene content of 3 to 4%, but more preferably an ethylene-rich polypropylene having an ethylene content of 5 to 10%. By using random polypropylene as the heat seal layer 14, flexibility is imparted, and the effect of improving the bending resistance and preventing cracks during molding is also demonstrated. However, even if it is a random polypropylene, if the ethylene content is increased, the slipperiness of the surface becomes worse. Therefore, liquid paraffin may be coated on the innermost surface of the random polypropylene. By the liquid paraffin coating, the Young's modulus of the heat seal layer 14 is reduced to make it easy to stretch and improve the slipperiness.

  Moreover, it is desirable to bond the base material 12 and the chemical conversion treatment surface of the barrier layer 13 by a dry laminating method. Examples of the adhesive used for the dry lamination of the substrate 12 and the aluminum phosphate chromate-treated surface include polyester, polyethyleneimine, polyether, cyanoacrylate, urethane, organic titanium, and polyetherurethane. Epoxy, polyester urethane, imide, isocyanate, polyolefin, and silicone adhesives can be used.

  Moreover, as a slip agent which forms the slip layer 11, the polydimethylsiloxane type block copolymer manufactured by copolymerizing a vinyl copolymer by using azo group containing polydimethylsiloxane amide as an initiator is used.

  A slip agent using a polydimethylsiloxane block copolymer is deposited and deposited on a molding die or a guide roll when continuously molding using a conventional fatty acid amide slip agent. There is no need to bake at a high temperature when a slip agent deposited on the film adheres to the film, or when a coating such as a slip agent of a fluororesin layer or a silicone resin layer is applied. Therefore, it is a material suitable as a slip agent.

The polydimethylsiloxane block copolymer has the following structure.
[1]. (A ¹ * a ² ) _l
[2]. a ¹ * (a ¹ * a ² ) _m
[3]. a ² * (a ¹ * a ² ) _n
Here, l, m, and n are integers of 1 to 10, a ¹ is a polydimethylsiloxane moiety represented by the following formula (Formula 1),

a ² is a vinyl polymer portion. First, a polymer initiator method is applied to synthesize the polydimethylsiloxane block copolymer. In the above polymer initiator method, for example, if a vinyl short monomer copolymerizable with a polymer having a polydimethylsiloxane moiety represented by the following formula (Chemical Formula 2) is copolymerized, the efficiency is improved. A block copolymer can be produced well.

  Further, if a polymeric initiator such as a peroxide type polymer initiator or an azo type polymer initiator is used, the polymerization can be carried out in two stages. For example, when an azo type polymer initiator is used, the polymerization is a two-stage polymerization represented by the following formulas (Chemical Formula 3) and (Chemical Formula 4):

Here, m, n, n ′ and l are integers of 1 or more, M ₁ is a macromonomer represented by the following formulas (Chemical Formula 5) and (Chemical Formula 6),

Here, M ₂ is a vinyl monomer copolymerizable with M ₁ , and, for example, R can be represented by the following formula (Formula 7).

and so on.

  Next, examples of the copolymerizable vinyl monomer used in the polymer initiator method include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl ( (Meth) acrylate, n-butyl (meth) acrylate, iso-butyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, Aliphatic or cyclic (meth) acrylate such as stearyl (meth) acrylate, theuryl (meth) acrylate, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, n-butyl vinyl ether, iso-butyl vinyl ether, etc. Nyl ethers, styrenes such as styrene and α-methylstyrene, nitrile monomers such as acrylonitrile and methacrylonitrile, aliphatic vinyls such as vinyl acetate and vinyl propionate, vinyl chloride, vinylidene chloride, vinyl fluoride, and fins , Dienes such as chloroprene, butadiene, acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, α, β-unsaturated carboxylic acid such as crotonic acid, atropic acid, citraconic acid, acrylamide, methacrylamide, Amides such as N, N-methylolacrylamide, N, N-dimethylacrylamide, diacetoneacrylamide, methylacrylamide glycolate methyl ether, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminomethyl (Meta) Acry , Amino group-containing monomers such as N, N-dimethylaminopropyl (meth) acrylate, epoxy group-containing monomers such as glycidyl (meth) acrylate and glycidyl allyl ether, 2-hydroxyethyl (meth) acrylate, Reaction products of 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl acrylate, allyl alcohol, Cardura E with acrylic acid, methacrylic acid, itaconic acid, maleic acid, crotonic acid, etc., other vinylpyrrolidone, vinylpyridine, vinylcarbazole Further, vinyl monomers having hydrolyzable silyl groups include γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, and γ-methacryloxy. Propyl methyl diethoxy silane, .gamma.-methacryloxypropyl methoxy silane, vinyl trimethoxy silane, can be used silane coupling agents such as vinyltriethoxysilane. The above monomers may be used alone or in combination of two or more. In this stage, (meth) acrylate is used in the meaning of acrylate or methacrylate.

  As a method for producing the polydimethylsiloxane block copolymer, it is produced by adding a vinyl monomer copolymerizable with the above-described polymer initiator into which polydimethylsiloxane is introduced and polymerizing it. The polymerization reaction is usually performed in a solution. In the above polymerization reaction, aromatic hydrocarbon solvents such as toluene and xylene, ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, propyl acetate, butyl acetate and isobutyl acetate, methanol, It can be used alone or as a mixed solvent such as alcohol solvents such as ethanol, isopropanol, butanol and isobutanol.

  In the above polymerization reaction, a known polymerization initiator such as benzoyl peroxide, lauryl peroxide, cumene hydroperoxide, dicumyl peroxide or the like may be used in combination as necessary. . In the polydimethylsiloxane block copolymer thus obtained, the siloxane content ratio is 1 to 60% by weight, preferably 5 to 40% by weight, and the content ratio of other copolymerizable vinyl monomers is 99 to 40%. It is desirable that the vinyl monomer has an OH group or an epoxy group contained therein, preferably 95% to 60% by weight. The polydimethylsiloxane block copolymer thus obtained has a high compatibility with other synthetic resins and is extremely effective as a compatibilizer. For example, silicone resin, polyvinyl acetoacetal, polyvinyl butyral, etc. A synthetic resin such as the above may be used as a mixture.

When a polydimethylsiloxane block copolymer is used as a slip agent, a resin solution containing the polydimethylsiloxane block copolymer obtained by the above polymerization reaction in a solution is applied by a known coating method such as a gravure printing method. The slip agent layer 11 can be obtained by applying to the surface of the base material layer and drying. The coating amount of the polydimethylsiloxane block copolymer is 0.05 g / m ² or more after drying, preferably 0.08 to 0.5 g / m ² , more preferably 0.1 to 0.2 g / m. m ² . Is less than the coating amount is 0.05 g / m ^2, there is no stable sliding properties can be obtained (slipperiness varies) risk, even at 0.5 g / m ² greater, although the sufficient effect of the sliding property is obtained This is not preferable in terms of cost effectiveness.

  Fig.2 (a) is an oblique schematic diagram which shows an example of the press work of the exterior body 10 which concerns on this invention. 21 is a male type, 10 is an outer package before pressing, and 22 is a female type. The outer package 10 before pressing faces the surface on which the slip layer 11 is provided on the female die 22 side, and presses the surface of the heat seal layer 14 with the male die 21.

  FIG. 2B is a cross-sectional view showing the force acting on the exterior body 10 when the exterior body 10 is pressed. When pressed into a concave shape, as the depth of the side wall portion 22a of the female die 22 increases, the slipperiness between the surface of the base material layer 12 and the inner surface of the female die 22 becomes important. When a downward press is applied to the exterior body 10, a downward force x (arrow) due to the male die 21 acts on the heat seal layer 14 in the side wall portion 22 a, whereas an upward force due to friction acts on the base material layer 12. y (arrow) works. Therefore, a shearing force parallel to the interlayer adhesion surface of the outer package 10 acts on the outer package 10, and the work exerted on the outer package 10 by the shear force increases as the depth of the side wall portion 22a of the female die 22 increases. Causes delamination of the laminated structure or cracking of the barrier layer.

  As a method for solving this problem, the slip layer 11 is provided on the surface of the base material layer 12 in order to reduce the dynamic friction coefficient between the base material layer 12 and the inner surface of the female die 22, It is conceivable to improve the adhesion strength between the layers.

  Here, as described above, the method of improving the interlayer adhesive strength of the outer package 10 uses aluminum which has been subjected to chemical conversion treatment on both surfaces of the barrier layer, or a cast polypropylene of a heat seal layer which is applied and baked with acid-modified polypropylene. The method of heat laminating etc. are mentioned.

  Moreover, the method of providing a slip agent layer on the surface of the base material layer and lowering the coefficient of dynamic friction includes coating the entire surface of the base material layer 12 with the slip agent.

  FIG. 3 is a schematic plan view showing the slip layer 11 provided on the exterior body 10 according to the present invention. In the exterior body 10 according to the present invention, the slip agent is not applied to the entire surface of the base material layer 12 as in the prior art, but the range in which the slip agent is applied is a range of 5% to 30% of the entire base material layer 12. Limited to. Thereby, at the time of a press work, the application part 11b of a slip agent can ensure sufficient slidability of the base material layer surface. Moreover, although the coating area of the application part 11b was limited, an adhesive seal may be adhered to the surface of the base material layer after press processing as will be described later, but the adhesion between the adhesive seal and the non-application part 11c is ensured. Because. In addition, the shape of the application part 11b and the non-application part 11c shown in FIG. 3 is not limited to this shape. However, in order to improve the slipperiness by providing the slip layer 11 and stably perform the press molding, it is necessary to provide the coating part 11b at the entire exterior body 10 at a predetermined interval.

  FIG. 4 is an oblique schematic view showing the lithium ion battery 1 enclosed in the plastic case 16. The lithium ion battery body is sealed in the press-molded concave exterior body 10b, and then the periphery is hermetically sealed to produce the lithium ion battery 1. However, when the lithium ion battery 1 is actually used, only the concave exterior body 10b is produced. So, it is weak in impact resistance and may cause cracking due to small scratches. Therefore, the lithium ion battery 1 is often stored and used in a plastic case 16. For example, when it is used for a mobile phone or the like, it is stored in a plastic case because it receives an impact when dropped.

  However, the lithium ion battery 1 may collide with the inner wall of the plastic case 16 in the plastic case 16, and the exterior body may be broken by impact. Therefore, the lithium ion battery 1 needs to be accommodated and fixed inside the plastic case 16 with an adhesive seal 17 or the like.

  FIG. 5A is an oblique schematic view showing the concave exterior body 10 b after press molding of the exterior body 10. When the slip layer 11 is provided on the outer package 10 before press molding and press molding is performed, the slip layer 11 remains fixed on the surface of the outer package 10 after press molding. This slip agent has very low adhesion to the adhesive seal 17. For this reason, the adhesive seal affixed to the surface of the concave exterior body 10 b is peeled off immediately, and the lithium ion battery cannot be bonded and fixed in the plastic case 16.

  However, as shown in FIG. 3, the surface of the exterior body 10 according to the present invention has an area of the application part 11b of the slip agent limited to a range of 5% to 30% of the surface of the base material layer, and other areas are not applied. Part 11c. Therefore, the adhesive seal 17 can be bonded to the non-applied portion 11 b to fix the concave exterior body 10 b inside the plastic case 16.

  5B and 5C are schematic plan views showing the slip layer 11 surrounded by the dotted line in FIG. 5A in an enlarged manner. In both figures, the application part 11b and the non-application part 11c of the slip agent are formed in a pattern that repeats alternately. Here, the pattern shape means a pattern in which the same shape is regularly and repeatedly arranged, such as a lattice shape, a mesh shape, or a line shape.

  FIG. 5 (b) is a diagram showing a case where the application part 11b of the slip agent is applied in a lattice shape, and FIG. 5 (c) shows the other part where the non-application part 11c of the slip agent is formed in a dot shape. It is a figure which shows the case where a slip agent is apply | coated. In this way, by applying the application portions 11b and the non-application portions 11c alternately to form a pattern, the application portion 11b makes the entire surface of the substrate layer slid evenly during pressing, and at the time of adhesion of the adhesive seal. The non-application part 11c makes the adhesive strength with the contact adhesive seal uniform. This further stabilizes the adhesion with the press molding and the adhesive seal.

  When the width L of the non-applied portion 11c is 0.1 mm or less, the slipperiness is improved, but the area of the non-applied portion that adheres to the adhesive seal becomes small, so that even if an adhesive seal is applied, it is immediately peeled. Moreover, when the width L of the non-application part 11c is 5.0 mm or more, although adhesiveness with an adhesive seal | sticker improves, slipperiness falls. On the contrary, when the width T of the application part 11b is 1.0 mm or less, the adhesiveness is improved, but the slipperiness is lowered. Moreover, in the case of 5.0 mm or more, although slipperiness improves, adhesiveness falls. Therefore, by adjusting the width T of the application part 11b and the width L of the non-application part 11c in the range of 1.0 mm to 5.0 mm, and providing the application part 11b and the non-application part 11c on the entire surface of the base material layer 12, A slip layer 11 having moderately stickiness and slipperiness can be formed.

  Moreover, the slip layer 11 suitable for the shape of the female mold | type 22 can be shape | molded by adjusting the magnitude | size of a dot or a grating | lattice, or changing the pattern pattern. For example, when the press working is performed, a particularly large frictional force acts on the peripheral edge portion of the base material layer 12 in contact with the side wall portion 22a (see FIG. 2) inside the female mold. For this reason, in order to ensure sufficient slidability of the peripheral portion, the coating area of the coating portion 11b in this portion can be provided wide. On the other hand, in the vicinity of the central portion of the base material layer 12 to which the adhesive seal 17 is bonded, the coating area of the application part 11b can be provided narrow, and the adhesion area between the non-application part 11c and the adhesive sheet can be increased.

  Moreover, the said pattern shape is shape | molded by printing a slip agent on the base-material layer surface. At this time, when the viscosity of the slip agent solution is low, the boundary between the application part and the non-application part may be blurred in a state in which the slip agent solution is not fixed on the surface of the base material layer and blots. At this time, the surface area of the non-application portion is not sufficiently secured, and the pressure-sensitive adhesive sheet does not adhere. In particular, since the surface of the base material layer is pressed against the mold at the time of pressing, a viscosity that can withstand it is required. Therefore, a resin having normal adhesiveness is added to the slip agent to ensure a certain viscosity.

  The present invention is not limited to the above-described embodiments, and various modifications are possible. Embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included in the present invention. Included in the technical scope. Hereinafter, the battery packaging material of the present invention will be specifically described in Examples.

In both Examples and Comparative Examples, a stretched nylon film nylon (thickness 25 μm) was used as a base material layer, aluminum 40 μm as a barrier layer, and cast polypropylene 30 μm as a heat seal layer. In each of the chemical conversion treatments, an aqueous solution composed of a phenol resin, a chromium fluoride compound, and phosphoric acid was used as a treatment solution, applied by a roll coating method, and baked under conditions where the film temperature was 180 ° C. or higher. The application amount of chromium is 10 mg / m ² (dry weight). Acid-modified polypropylene (hereinafter abbreviated as acid-modified PP) was applied by a roll coating method and baked under conditions where the aluminum temperature was 180 ° C. or higher. The coating amount of the acid-modified PP was 3 g / m ² (dry weight). For the slip layer, a polydimethylsiloxane block copolymer was used as a slip agent. The coating amount of the polydimethylsiloxane block copolymer was 0.15 g / m ² (dry weight).

  A chemical conversion treatment is performed on both sides of aluminum, and one side of the chemical conversion treatment surface is bonded with a stretched nylon film by a dry laminating method via a two-component curable polyurethane adhesive, and the other chemical conversion treatment surface is roll-coated with acid-modified PP. The film was applied and baked by a method, and a cast polypropylene film was laminated on the acid-modified PP surface by a heat laminating method. Thereafter, the slip agent was printed and fixed on the surface of the stretched nylon film by a gravure printing method to form a slip layer. At this time, the coated area of the application part of the slip agent was applied so as to be 6%, 11%, and 25% of the whole stretched nylon film to obtain the battery packaging material of the present invention (Inventions 1 to 3). Further, the coating concentration of the battery according to the present invention (the present invention) is applied by diluting the coating concentration of the slip agent to 1/2 and applying the coated area of the coated portion to 6%, 11% and 25% of the entire stretched nylon film. 4-6) were obtained.

  Further, a battery packaging material in which the coating area of the application part of the slip agent was 0% by the same production method as above was designated as Comparative Example 1.

  Further, a battery packaging material in which the coating area of the application part of the slip agent was 100% by the same production method as above was designated as Comparative Example 2.

  For the battery packaging materials of the present inventions 1 to 6 and Comparative Examples 1 and 2 obtained above, the following evaluation methods were used to evaluate the limit moldability, dynamic friction coefficient, cello tape (registered trademark) peel strength, and oil-based magic ink adhesion. The results are summarized in FIG.

  As a method for evaluating formability, a sample cut into 80 × 120 mm square was stored in a thermostatic chamber (40 ° C., 90% RH) for 14 days, and then the sample was molded into a mold with a diameter of 30 mm × 50 mm (female Mold) and a corresponding molding die (male), and cold-molding 10 samples each by changing the molding depth from 0.5mm to 0.5mm. The forming depth at which pinholes and cracks did not occur in any of the ten samples of the ridges or aluminum foil was taken as the limit forming depth, and the forming depth was shown as an evaluation value.

  As a method for evaluating the dynamic friction coefficient, a sample cut into an 80 × 120 mm square is stored in a thermostatic chamber (40 ° C., 90% RH) for 14 days, and then the outermost layer is a stretched nylon film nylon and the innermost layer is cast. The dynamic friction coefficient of polypropylene was measured and indicated as an evaluation value.

  As an evaluation method of the cellotape (registered trademark) peel strength, a sample cut to 80 × 120 mm square was pressed at a pressure of 5 MPa (upper metal, lower silicon rubber), and then applied to the surface on which the slip agent was applied. ), And cello tape (registered trademark) is cut to a width of 15 mm, and measured with an autograph (manufactured by Shimadzu Corporation, AGS-50D (trade name)) at a chucking dimension of 30 mm and a bowing speed of 300 mm / min. The value is shown. The unit is N / 15 mm width.

  As a method for evaluating the adhesion property of oil-based magic ink, the surface of the sample coated with the slip agent layer cut to 80 × 120 mm square is marked with the oil-based magic ink, and the oil repellency of the oil-based magic ink is evaluated. In general, the product number or the like is generally printed on the surface of the battery packaging material, but the ink adhesion at that time is observed.

  As apparent from FIG. 6, it was found that the limit moldability and the dynamic friction coefficient were also improved in proportion to the coating area of the slip agent layer. On the contrary, it was found that the cellotape (registered trademark) peel strength and the oil-based magic ink adhesion decreased in proportion to the coating area of the slip agent layer. In particular, Comparative Example 1 in which the coat area is 0% has a high cellotape (registered trademark) peel strength, but is extremely inferior in moldability. Moreover, although the comparative example 2 which makes a coat area 100% is excellent in a moldability, it is inferior to a cellotape (trademark) peeling strength. It was also found that the coating solution concentration did not significantly affect the moldability and adhesiveness.

  As described above, by adjusting the coating area of the slip agent to a range of 5% or more and 30% or less, a battery packaging material having appropriateness in press molding and excellent in adhesiveness and adhesiveness with an adhesive label is provided. I found out that I could do it.

These are schematic sectional drawings which show the layer structure of the packaging material for batteries of this invention. These are the diagonal schematic which shows the process of embossing the packaging material for batteries of this invention. These are the schematic diagrams which show the slip layer which concerns on the packaging material for batteries of this invention. These are the diagonal schematic which shows the usage aspect of the lithium ion battery concerning the packaging material for batteries of this invention. These are the expansion schematic which shows the slip layer after the press work in the packaging material for batteries of this invention. These are the tables | surfaces which show the evaluation result about the moldability in a battery packaging material of this invention, a dynamic friction coefficient, tape peeling strength, and ink adhesion. These are the schematic diagrams which show the conventional embossing process. FIG. 3 is an oblique outline view showing an exploded view of a conventional embossed type lithium ion battery.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lithium ion battery 2 Lithium ion battery main body 3 Cell (electric storage part)
4 Tab 4a Tab material 4b Adhesive film for sealing lithium battery metal terminal part 5 Exterior body 7 Holding part 8 Positive electrode current collector 10 Exterior body 11 Slip layer 11b Application part 11c Non-application part 12 Base material layer 13 Barrier layer 13a Chemical conversion treatment Layer (barrier layer surface)
14 Innermost layer (heat seal layer)
DESCRIPTION OF SYMBOLS 15 Adhesive layer 16 Plastic case 17 Adhesive seal 20 Press molding part 21 Male part 22 Female type | mold 22a Side wall part 23 Cavity

Claims (4)

In a battery packaging material comprising at least an outermost base material layer, a barrier layer made of a metal foil, and a polyolefin resin layer having heat sealability as an innermost layer,
A slip layer is provided by applying a slip agent substantially uniformly at a predetermined interval on the entire surface of the base material layer,
The battery packaging material, wherein the application area of the slip agent is in the range of 5% to 30% of the entire surface area of the base material layer.   The battery packaging material according to claim 1, wherein an interval between the application part and the non-application part of the slip agent is 0.1 mm or more and 5.0 mm or less, respectively.   The battery packaging material according to claim 1 or 2, wherein the coating part and the non-coating part are formed in a pattern that repeats alternately.   The battery packaging material according to any one of claims 1 to 3, wherein the slip agent contains a polydimethylsiloxane-based block copolymer.