JP2022000853A - Battery packaging material, method of producing the same, and battery - Google Patents

Abstract

To provide a battery packaging material excellent in water vapor barrier properties and having excellent formability and electrolyte resistance.SOLUTION: A battery packaging material comprises a laminate in which at least a base material layer, an adhesive layer, an aluminum foil layer, and a heat welding resin layer are laminated in order. A moisture barrier layer is provided on at least one side of the aluminum foil layer.SELECTED DRAWING: None

Description

The present invention relates to a packaging material for a battery, a method for manufacturing the same, and a battery.

Conventionally, various types of batteries have been developed, but in all batteries, a packaging material is an indispensable member for encapsulating a battery element such as an electrode or an electrolyte. Conventionally, metal packaging materials have been widely used for battery packaging.

On the other hand, in recent years, with the improvement of high performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones and the like, batteries are required to have various shapes, and are required to be thinner and lighter. However, the metal packaging material for batteries, which has been widely used in the past, has a drawback that it is difficult to keep up with the diversification of shapes and there is a limit to weight reduction.

Therefore, in recent years, as a packaging material for batteries that can be easily processed into various shapes and can be made thinner and lighter, a film-like laminate in which a base material / aluminum foil layer / heat-weldable resin layer is sequentially laminated. Has been proposed (for example, Patent Document 1).

The battery packaging material composed of such a film-like laminate has a problem that the moisture barrier property tends to decrease when pinholes are present in the barrier layer. Further, the thinner the barrier layer, the higher the probability that pinholes are generally present. When the moisture barrier property of the battery packaging material is lowered, moisture easily permeates from the outside of the battery to the battery element. Since the permeated water reacts with the electrolytic solution of the battery element, there is a problem that hydrogen fluoride or the like is generated inside the battery.

Japanese Unexamined Patent Publication No. 2008-287971

Under such circumstances, a main object of the present invention is at least in a battery packaging material composed of a laminate in which a base material layer, an adhesive layer, an aluminum foil layer, and a heat-weldable resin layer are sequentially laminated. The present invention is to provide a packaging material for a battery having excellent barrier properties.

The present inventors have made diligent studies to solve the above problems. As a result, in a battery packaging material composed of a laminate in which at least a base material layer, an adhesive layer, an aluminum foil layer, and a heat-welding resin layer are sequentially laminated, a moisture barrier layer is provided on at least one side of the aluminum foil layer. It has been found that a packaging material for a battery having excellent water vapor barrier properties can be obtained by providing the same. The present invention has been completed by further studies based on these findings.

That is, the present invention provides a battery packaging material and a battery according to the following aspects.
Item 1. It is composed of a laminate having at least a base material layer, an adhesive layer, an aluminum foil layer, and a heat-weldable resin layer in this order.
A battery packaging material comprising a moisture barrier layer on at least one side of the aluminum foil layer.
Item 2. Item 2. The battery packaging material according to Item 1, wherein the total thickness of the laminate is 55 μm or less.
Item 3. Item 2. The packaging material for a battery according to Item 1 or 2, wherein the moisture barrier layer is provided between the aluminum foil layer and the heat-weldable resin layer.
Item 4. The aluminum foil layer has pinholes and
Item 6. The battery packaging material according to any one of Items 1 to 3, wherein the pinhole is filled with the moisture barrier layer.
Item 5. Item 2. The battery packaging material according to any one of Items 1 to 4, wherein the moisture barrier layer has a thickness of 1 μm or less.
Item 6. Item 2. The battery packaging material according to any one of Items 1 to 5, wherein the moisture barrier layer is formed of at least one selected from the group consisting of fluororesin, polyethylene naphthalate, and polyarylate.
Item 7. Item 6. The packaging material for a battery according to any one of Items 1 to 6, wherein the thickness of the aluminum foil layer is 20 μm or less.
Item 8. Item 6. The battery packaging material according to any one of Items 1 to 7, which is a packaging material for a secondary battery.
Item 9. A battery in which a battery element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the battery packaging material according to any one of Items 1 to 8.
Item 10. At least, a step of laminating the base material layer, the adhesive layer, the aluminum foil layer, and the heat-welding resin layer in this order to obtain a laminate.
A step of covering at least one side of the aluminum foil layer with a moisture barrier layer,
A method of manufacturing packaging materials for batteries.

According to the present invention, in a battery packaging material composed of a laminate in which a base material layer, an adhesive layer, an aluminum foil layer, and a heat-welding resin layer are sequentially laminated, moisture is provided on at least one side of the aluminum foil layer. Since the barrier layer is provided, the moisture barrier property is improved and the water vapor barrier property is excellent.

It is a figure which shows an example of the cross-sectional structure of the packaging material for a battery of this invention. It is a figure which shows an example of the cross-sectional structure of the packaging material for a battery of this invention. It is a figure which shows an example of the cross-sectional structure of the packaging material for a battery of this invention. It is a figure which shows an example of the cross-sectional structure of the packaging material for a battery of this invention.

The packaging material for a battery of the present invention is composed of at least a laminate in which a base material layer, an adhesive layer, an aluminum foil layer, and a heat-weldable resin layer are sequentially laminated, and moisture is provided on at least one side of the aluminum foil layer. It is characterized in that a barrier layer is provided. Hereinafter, the battery packaging material of the present invention will be described in detail.

In this specification, the numerical range indicated by "~" means "greater than or equal to" and "less than or equal to". For example, the notation of 2 to 15 mm means 2 mm or more and 15 mm or less.

1. 1. Laminated structure of battery packaging material As shown in FIG. 1, the battery packaging material is a laminated structure in which at least a base material layer 1, an adhesive layer 2, an aluminum foil layer 3, and a heat-weldable resin layer 4 are sequentially laminated. It consists of a body. Further, in the battery packaging material of the present invention, the moisture barrier layers 6a and 6b are provided on at least one side of the aluminum foil layer. The moisture barrier layer 6a is formed on the base material layer 1 side of the aluminum foil layer 3, and the moisture barrier layer 6b is formed on the heat-welding resin layer 4 side of the aluminum foil layer 3.

In the packaging material for batteries of the present invention, the base material layer 1 is on the outermost layer side, and the heat-weldable resin layer 4 is on the innermost layer. That is, when the battery is assembled, the heat-weldable resin layers 4 located on the peripheral edge of the battery element are heat-welded to each other to seal the battery element, thereby sealing the battery element.

Further, as shown in FIG. 2, the packaging material for a battery of the present invention has heat-weldability between the aluminum foil layer 3 and the heat-weldable resin layer 4 (in the case of having the water-weldable resin layer 6b, the water-weldable layer 6b). An adhesive layer 5 may be provided between the resin layer 4 and the resin layer 4), if necessary, for the purpose of enhancing these adhesiveness.

Further, an acid resistant film 7 may be provided on at least one surface of the aluminum foil layer 3, if necessary.

The total thickness of the laminate constituting the packaging material for a battery of the present invention may be, for example, 80 μm or less. The battery packaging material of the present invention is excellent in water vapor barrier property because the moisture barrier layer is provided on at least one side of the aluminum foil layer even when the thickness is extremely thin.

From the viewpoint of making the total thickness of the laminate constituting the battery packaging material of the present invention as thin as possible, the upper limit is, for example, 80 μm or less, further 75 μm or less, further 65 μm or less, and further 55 μm or less. The lower limit is, for example, 40 μm or more, more preferably 45 μm or more. From the same viewpoint, the range of the total thickness of the laminated body is preferably about 40 to 80 μm, about 45 to 80 μm, about 40 to 75 μm, about 45 to 75 μm, about 40 to 65 μm, about 45 to 65 μm, and 40 to. About 55 μm and about 45 to 55 μm can be mentioned. The battery packaging material of the present invention can be made extremely thin in this way and can contribute to the improvement of the energy density of the battery. When the formability is emphasized, the lower limit of the total thickness of the laminate is preferably 50 μm or more, and the range of the total thickness is preferably about 50 to 80 μm, about 50 to 75 μm, and so on. Examples thereof include about 50 to 65 μm and about 50 to 55 μm.

The packaging material for a battery is generally manufactured as a strip-shaped laminated film (laminated body) on a production line, and is distributed as a rolled-up body wound into a roll shape for storage, transportation, and the like. Then, at the time of manufacturing the battery, the packaging material for the battery is unwound from the winding body, cut into a predetermined shape according to the product specifications of the battery, and used.

When the packaging material for a battery of the present invention is in the form of a wound body, the length of the laminated film constituting the packaging material for a battery is not particularly limited, but may be, for example, 200 m or more, preferably about 200 to 4000 m. The width of the laminated film is, for example, about 0.01 to 1 m, preferably about 0.1 to 1 m. In the roll-shaped wound body, the diameter of the circular cross section in the direction perpendicular to the width direction of the laminated film is, for example, 150 mm or more, preferably 220 mm or more. The upper limit of the diameter of the circular cross section is usually about 1000 mm. However, the diameter of the circular cross section of the wound body is the diameter when the battery packaging material is wound around the core tube made of resin, paper, etc., and the outer diameter of the core tube is usually 70 to 70 to. It is about 180 mm.

2. 2. Each layer forming the packaging material for batteries [base material layer 1]
In the packaging material for a battery of the present invention, the base material layer 1 is a layer formed on the outermost layer side. The material forming the base material layer 1 can be provided with the above-mentioned physical properties, and is not particularly limited as long as it has an insulating property. Examples of the material forming the base material layer 1 include polyester resin, polyamide resin, epoxy resin, acrylic resin, fluororesin, polyurethane resin, silicon resin, phenol resin, and resin films such as mixtures and copolymers thereof. Can be mentioned. Among these, polyester resin and polyamide resin are preferable, and biaxially stretched polyester resin and biaxially stretched polyamide resin are more preferable. Specific examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, copolymerized polyester, polycarbonate and the like. Specific examples of the polyamide resin include nylon 6, nylon 66, a copolymer of nylon 6 and nylon 66, nylon 6, 10, and polymethoxylylen adipamide (MXD6).

The base material layer 1 may be formed of one layer of resin film, but may be formed of two or more layers of resin film in order to improve pinhole resistance and insulating property. For example, when the base material layer 1 is formed of two layers of resin film, it is preferably made of polyester resin / polyamide resin, and more preferably made of polyethylene terephthalate / nylon. In the laminated structure, it is preferable to laminate the base material layer 1 so that the polyester resin or polyethylene terephthalate is located on the outermost layer side.

When the base material layer 1 is formed of a multi-layered resin film, the two or more resin films may be laminated via an adhesive component such as an adhesive or an adhesive resin, and the type and amount of the adhesive component used may be used. The same applies to the case of the adhesive layer 2 described later. The method for laminating two or more layers of resin films is not particularly limited, and a known method can be adopted, and examples thereof include a dry laminating method and a sandwich laminating method, and a dry laminating method is preferable. When laminating by the dry laminating method, it is preferable to use a urethane-based adhesive as the adhesive layer. At this time, the thickness of the adhesive layer may be, for example, about 2 to 5 μm.

The thickness of the base material layer 1 is not particularly limited as long as it can exhibit the function as the base material layer, but from the viewpoint of reducing the thickness of the laminated body, it is preferably about 6 to 12 μm, more preferably about 9 to 12 μm. ..

[Adhesive layer 2]
In the packaging material for batteries of the present invention, the adhesive layer 2 is a layer provided between the base material layer 1 and the aluminum foil layer 3 in order to firmly bond them.

The adhesive layer 2 is formed by an adhesive capable of adhering the base material layer 1 and the aluminum foil layer 3. The adhesive used to form the adhesive layer 2 may be a two-component curable adhesive or a one-component curable adhesive. Further, the adhesive mechanism used for forming the adhesive layer 2 is not particularly limited, and may be any of a chemical reaction type, a solvent volatile type, a heat melting type, a thermal pressure type and the like.

Specific examples of the adhesive component that can be used to form the adhesive layer 2 include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, and copolymerized polyester; Polyether-based adhesives; Polyurethane-based adhesives; Epoxy resins; Phenolic resin-based resins; Polyethylene-based resins such as nylon 6, nylon 66, nylon 12, and copolymerized polyamides; polyolefins, carboxylic acid-modified polyolefins, metal-modified polyolefins, etc. Polyolefin resin, Polyvinyl acetate resin; Cellulous adhesive; (Meta) acrylic resin; Polyimide resin; Amino resin such as urea resin and melamine resin; Rubber such as chloroprene rubber, nitrile rubber, styrene-butadiene rubber; Examples include silicone-based resins. These adhesive components may be used alone or in combination of two or more. Among these adhesive components, a polyurethane-based adhesive is preferable.

The thickness of the adhesive layer 2 is not particularly limited as long as it can function as an adhesive layer, but is preferably about 1 to 10 μm, more preferably about 2 to 5 μm, from the viewpoint of reducing the thickness of the laminated body. ..

[Aluminum foil layer 3]
In the battery packaging material of the present invention, the aluminum foil layer 3 is a layer that functions as a barrier layer for improving the strength of the battery packaging material and preventing water vapor, oxygen, light, etc. from entering the inside of the battery. be. From the viewpoint of suppressing the occurrence of wrinkles and pinholes in the aluminum foil layer 3 during the production of the packaging material for batteries, the aluminum foil layer 3 is, for example, an aluminum foil layer 3 that has been annealed (JIS H4160: 1994 A8021H-O,). It is more preferable to form it with a soft aluminum foil such as JIS H4160: 1994 A8079H-O, JIS H4000: 2014 A8021P-O, JIS H4000: 2014 A8079P-O).

The thickness of the aluminum foil layer 3 is not particularly limited as long as it can function as a barrier layer such as water vapor, but from the viewpoint of reducing the thickness of the laminated body, it is preferably 20 μm or less, more preferably about 7 to 15 μm.

At least one side, preferably both sides, of the aluminum foil layer 3 may be subjected to chemical conversion treatment in order to stabilize adhesion, prevent melting and corrosion, and the like. Here, the chemical conversion treatment refers to a treatment for forming an acid-resistant film 7 on the surface of an aluminum foil. The chemical conversion treatment includes, for example, chromate treatment using a chromium compound such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium bicarbonate, acetylacetate chromate, chromium chloride, potassium sulfate chromium; phosphorus. Phosphoric acid treatment using a phosphoric acid compound such as sodium acid, potassium phosphate, ammonium phosphate, polyphosphoric acid; chemical treatment using an aminoated phenol polymer and the like can be mentioned.

In the packaging material for batteries of the present invention, the aluminum foil layer 3 may have pinholes. That is, in the packaging material for a battery of the present invention, even when the aluminum foil layer 3 has pinholes, the pinholes are filled by the moisture barrier layer described later, so that the pinholes are present. As a result, the decrease in water vapor barrier property is effectively suppressed. The fact that the pinholes of the aluminum foil layer 3 are filled with the moisture barrier layer means that the cross section in the thickness direction of the portion of the aluminum foil layer of the packaging material for a battery of the present invention in which the pinholes are formed is formed by a microtome or the like. It can be made and confirmed by observing the cross section with a microscope.

[Moisture barrier layers 6a, 6b]
In the battery packaging material of the present invention, the moisture barrier layer is provided on at least one side of the aluminum foil layer. As shown in FIGS. 1 and 2, the moisture barrier layer 6a is formed on the base material layer 1 side of the aluminum foil layer 3, and the moisture barrier layer 6b is the heat-welding resin layer 4 of the aluminum foil layer 3. It is formed on the side.

The moisture barrier layer 6a is preferably provided between the base material layer 1 (adhesive layer 2 when the adhesive layer 2 is provided) and the aluminum foil layer 3, and is the base material of the aluminum foil layer 3. It is more preferable that the surface is provided on the surface on the layer 1 side (in the case of having the above-mentioned acid-resistant film 7, the surface of the acid-resistant film 7). Further, the moisture barrier layer 6b is preferably provided between the aluminum foil layer 3 and the heat-weldable resin layer 4 (adhesive layer 5 when the adhesive layer 5 is provided), and the aluminum foil layer 3 is preferably provided. It is more preferable that the surface is provided on the surface of the heat-welding resin layer 4 side (in the case of having the above-mentioned acid-resistant film 7, the surface of the acid-resistant film 7).

As shown in FIG. 3, the moisture barrier layer may be provided only on the heat-welding resin layer 4 side of the aluminum foil layer 3, or as shown in FIG. 4, the base material of the aluminum foil layer 3 is provided. It may be provided only on the layer 1 side. When the moisture barrier layer is provided only on the base material layer 1 side of the aluminum foil layer 3, it is preferable to provide an acid resistant film 7 on the surface of the aluminum foil layer 3 on the heat-welding resin layer 4 side. ..

As described above, the packaging material for batteries is generally manufactured as a strip-shaped laminated film (laminated body) on a production line, and is distributed as a rolled-up body wound into a roll shape for storage, transportation, and the like. .. Therefore, as for the aluminum foil forming the aluminum foil layer described above, strips of several hundred to several thousand m are laminated in the wound body. It is known that such a long aluminum foil may have very few pinholes, and the number of pinholes increases as the thickness of the aluminum foil becomes thinner (note that the number of pinholes increases). The number is usually 10 pieces / 1000 m ² or less). Further, as described above, cracks, pinholes, etc. are likely to occur when molding a thin battery packaging material. Even for thick aluminum foil, pinholes may occur depending on the material and manufacturing method of the aluminum foil.

As described above, the acid-resistant film 7 may be provided on the surface of the aluminum foil layer 3, and in the present invention, when the acid-resistant film 7 is provided on the surface of the aluminum foil layer 3. , Moisture barrier layers 6a and 6b are formed on the acid resistant film 7 of the aluminum foil layer 3.

In the packaging material for batteries of the present invention, since the moisture barrier layer is formed on the surface of the aluminum foil layer, the pinholes of the aluminum foil layer can be filled (closed) with the moisture barrier layer, and the water vapor barrier property is deteriorated. Can be effectively suppressed. Further, by filling the pinholes of the aluminum foil layer with the moisture barrier layer, it is possible to suppress the occurrence of cracks in the aluminum foil layer. Further, by filling the pinholes of the aluminum foil layer with the moisture barrier layer, the electrolytic solution resistance of the battery packaging material is also improved. On the other hand, for example, in the configuration in which the vapor-filmed film is laminated on the surface of the aluminum foil layer, the pinholes of the aluminum foil layer are not filled, so that the effect of suppressing the deterioration of the water vapor barrier property is low. Further, in the configuration in which the thin-film vapor deposition film is laminated on the surface of the aluminum foil layer, the electrolytic solution resistance of the adhesion strength between the thin-film deposition layer and the film layer of the vapor-film deposition film is poor, so that the electrolytic solution resistance is significantly inferior. The present invention is particularly effective when a thin aluminum foil is used, but it is also effective when a thick aluminum foil is used.

From the viewpoint of further enhancing the water vapor barrier property, it is preferable that the moisture barrier layer is provided on the heat-welding resin layer 4 side of the aluminum foil layer. That is, it is preferable that the packaging material for a battery of the present invention includes at least a moisture barrier layer 6b.

The thickness of the moisture barrier layers 6a and 6b is not particularly limited, but from the viewpoint of improving the moldability and the electrolytic solution resistance while improving the water vapor barrier property, the upper limit is preferably about 1 μm or less, more preferably. It is preferably about 0.5 μm or less, more preferably about 0.4 μm or less, and the lower limit is preferably about 0.08 μm or more. The thickness range of the moisture barrier layers 6a and 6b is preferably about 0.08 to 1 μm, about 0.08 to 0.5 μm, and about 0.08 to 0.4 μm. When the thicknesses of the moisture barrier layers 6a and 6b have such values, it is possible to effectively achieve both moisture barrier properties and moldability.

For the thickness of the moisture barrier layers 6a and 6b, a cross section in the thickness direction of the battery packaging material other than the portion where the pinhole of the aluminum foil layer of the present invention is formed is prepared by a microtome or the like, and the cross section is observed with a microscope. It can be measured by doing.

The moisture barrier layers 6a and 6b can be formed, for example, by applying a resin to the surface of the aluminum foil layer. The resin forming the moisture barrier layers 6a and 6b is not particularly limited as long as it is a resin having low moisture permeability, but from the viewpoint of enhancing the water vapor barrier property and improving the moldability and the electrolytic solution resistance, fluoropolymer is preferable. Examples thereof include resin, polyethylene naphthalate, and polyarylate. As the resin forming the moisture barrier layers 6a and 6b, one type may be used alone, or two or more types may be used in combination. Among these, fluororesin is preferable, polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene-ethylene copolymer (ETFE), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-hexa. Fluoropropylene copolymer (FEP) and the like are particularly preferable.

It can be confirmed by analysis such as X-ray photoelectron spectroscopy (ESCA) and infrared spectroscopy (IR) that the moisture barrier layers 6a and 6b are composed of fluororesin. Further, it can be confirmed by IR or the like that the fluororesin is PCTFE, ETFE, PFA, or FEP.

Further, from the viewpoint of improving the moldability and the electrolytic solution resistance while improving the water vapor barrier property of the battery packaging material, the moisture barrier layers 6a and 6b have a temperature of 40 ° C. when a resin film having a thickness of 50 μm is used. Relative humidity 90% RH, water vapor transmission rate measured in an environment of 1 atm is 10 g / (m ²⁾
-It is preferable that it is formed of a resin having 24h) or less. The water vapor transmission rate is a value measured by the method described in Examples.

The moisture barrier layers 6a and 6b are formed by applying and drying a solution containing the above resin on the surface of the aluminum foil layer by a bar coating method, a roll coating method, a gravure coating method, a dipping method or the like. Can be done.

Further, the surfaces of the moisture barrier layers 6a and 6b can be subjected to surface activation treatments such as corona treatment, blast treatment, oxidation treatment and ozone treatment to improve the adhesion with the adjacent layer.

[Heat-welded resin layer 4]
In the battery packaging material of the present invention, the heat-weldable resin layer 4 corresponds to the innermost layer, and is a layer in which the heat-weldable resin layers are heat-welded to each other when the battery is assembled to seal the battery element.

The resin component used in the heat-welable resin layer 4 is not particularly limited as long as it can be heat-welded, and examples thereof include polyolefins, cyclic polyolefins, carboxylic acid-modified polyolefins, and carboxylic acid-modified cyclic polyolefins. That is, the heat-welded resin layer 4 may contain a polyolefin skeleton, and preferably contains a polyolefin skeleton. The fact that the heat-weldable resin layer 4 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, or the like, and the analysis method is not particularly limited. For example, when the maleic anhydride-modified polyolefin is measured by infrared spectroscopy, peaks derived from maleic anhydride are detected near a wave number of 1760 cm-1 and a wave number of 1780 cm-1. However, if the degree of acid denaturation is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

Specific examples of the polyolefin include polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; homopolypropylene, a block copolymer of polypropylene (for example, a block copolymer of propylene and ethylene), and polypropylene. Polypropylene such as random copolymers of polyethylene (eg, random copolymers of propylene and ethylene); polyethylene-butene-propylene tarpolymers and the like. Among these polyolefins, polyethylene and polypropylene are preferable.

The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer, and examples of the olefin which is a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, and isoprene. .. Examples of the cyclic monomer which is a constituent monomer of the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic diene such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, norbornadiene and the like. Styrene is also mentioned as a constituent monomer. Among these polyolefins, cyclic alkene is preferable, and norbornene is more preferable.

The carboxylic acid-modified polyolefin is a polymer modified by block-polymerizing or graft-polymerizing the polyolefin with a carboxylic acid. Examples of the carboxylic acid used for modification include maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, itaconic anhydride and the like.

The carboxylic acid-modified cyclic polyolefin means that a part of the monomer constituting the cyclic polyolefin is copolymerized in place of α, β-unsaturated carboxylic acid or its anhydride, or α, β with respect to the cyclic polyolefin. -A polymer obtained by block polymerization or graft polymerization of unsaturated carboxylic acid or its anhydride. The same applies to the cyclic polyolefin that is modified with carboxylic acid. The carboxylic acid used for the modification is the same as the carboxylic acid used for the modification of the carboxylic acid-modified polyolefin.

Among these resin components, carboxylic acid-modified polyolefin is preferable; and carboxylic acid-modified polypropylene is more preferable.

The heat-weldable resin layer 4 may be formed of one type of resin component alone, or may be formed of a blended polymer in which two or more types of resin components are combined. Further, the heat-weldable resin layer 4 may be formed of only one layer, or may be formed of two or more layers with the same or different resin components.

The thickness of the heat-weldable resin layer 4 is not particularly limited as long as it can exhibit the function as the heat-weldable resin layer, but is preferably about 15 to 25 μm, more preferably 20 from the viewpoint of reducing the thickness of the laminated body. The range is about 25 μm.

[Adhesive layer 5]
In the packaging material for a battery of the present invention, the adhesive layer 5 is a layer provided as necessary between the aluminum foil layer 3 and the heat-weldable resin layer 4 in order to firmly bond them.

The adhesive layer 5 is formed of an adhesive capable of adhering the aluminum foil layer 3 and the heat-weldable resin layer 4 (in the case of having the moisture barrier layer 6b, the moisture barrier layer 6b and the heat-weldable resin layer 4). To. Regarding the adhesive used for forming the adhesive layer 5, the adhesive mechanism, the types of adhesive components, and the like are the same as in the case of the adhesive layer 2. Examples of the adhesive component used in the adhesive layer 5 include a polyolefin-based resin, more preferably a carboxylic acid-modified polyolefin, and particularly preferably a carboxylic acid-modified polypropylene. That is, the adhesive layer 5 may contain a polyolefin skeleton, and preferably contains a polyolefin skeleton. The fact that the adhesive layer 5 contains a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, or the like, and the analysis method is not particularly limited. For example, when the maleic anhydride-modified polyolefin is measured by infrared spectroscopy, peaks derived from maleic anhydride are detected near a wave number of 1760 cm-1 and a wave number of 1780 cm-1. However, if the degree of acid denaturation is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

The thickness of the adhesive layer 5 is not particularly limited as long as it can function as an adhesive layer, but from the viewpoint of reducing the thickness of the laminated body, for example, about 1 to 10 μm, preferably about 2 to 5 μm can be mentioned.

[Surface coating layer]
In the packaging material for a battery of the present invention, for the purpose of improving designability, electrolytic solution resistance, scratch resistance, moldability, etc., as necessary, on the base material layer 1 (aluminum foil of the base material layer 1). A surface coating layer (not shown) may be provided on the side opposite to the layer 3 as needed. The surface coating layer is a layer located on the outermost layer when the battery is assembled.

The surface coating layer can be formed of, for example, polyvinylidene chloride, polyester resin, urethane resin, acrylic resin, epoxy resin, or the like. Among these, the surface coating layer is preferably formed of a two-component curable resin. Examples of the two-component curable resin forming the surface coating layer include a two-component curable urethane resin, a two-component curable polyester resin, and a two-component curable epoxy resin. Further, an additive may be added to the surface coating layer.

Examples of the additive include fine particles having a particle size of about 0.5 nm to 5 μm. The material of the additive is not particularly limited, and examples thereof include metals, metal oxides, inorganic substances, and organic substances. The shape of the additive is also not particularly limited, and examples thereof include a spherical shape, a fibrous shape, a plate shape, an amorphous shape, and a balloon shape. As additives, specifically, talc, silica, graphite, kaolin, montmoriloid, montmorillonite, synthetic mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, Neodium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotubes, high Examples thereof include melting point nylon, crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper and nickel. These additives may be used alone or in combination of two or more. Among these additives, silica, barium sulfate, and titanium oxide are preferable from the viewpoint of dispersion stability and cost. Further, the additive may be subjected to various surface treatments such as an insulation treatment and a high dispersibility treatment on the surface.

The method for forming the surface coating layer is not particularly limited, and examples thereof include a method of applying a two-component curable resin for forming the surface coating layer on one surface of the base material layer 1. When the additive is blended, the additive may be added to the two-component curable resin, mixed, and then applied.

The content of the additive in the surface coating layer is not particularly limited, but is preferably about 0.05 to 1.0% by mass, and more preferably about 0.1 to 0.5% by mass.

The thickness of the surface coating layer is not particularly limited as long as it can exhibit the above functions as the surface coating layer, but from the viewpoint of reducing the thickness of the laminate, for example, it is about 0.5 to 10 μm, preferably about 1 to 5 μm. Can be mentioned.

3. 3. Method for Manufacturing Battery Packaging Material The method for producing a battery packaging material of the present invention is not particularly limited as long as a laminate in which each layer having a predetermined composition is laminated can be obtained, and is not particularly limited, for example, at least a base material layer and adhesion. A step of laminating the agent layer, the aluminum foil layer, and the heat-welding resin layer in this order to obtain a laminate is provided, and in the laminating of the aluminum foil layer, a moisture barrier layer is formed on at least one surface. It is possible to adopt a manufacturing method using the aluminum foil.

That is, in the lamination of the aluminum foil layer 3, the moisture barrier layers 6a and 6b described in the column of "2. Each layer forming the packaging material for a battery" are formed on at least one surface, and each layer is laminated. By doing so, the packaging material for a battery of the present invention can be manufactured.

Further, at least a step of laminating the base material layer, the adhesive layer, the aluminum foil layer, and the heat-welding resin layer in this order to obtain a laminated body, and at least one side of the aluminum foil layer are moistened. The packaging material for a battery of the present invention can also be produced by a method including a step of coating with a barrier layer.

As described above, the surface of the aluminum foil layer 3 may be provided with an acid resistant film by the above-mentioned chemical conversion treatment or the like, and in the present invention, the surface of the aluminum foil layer 3 may be provided with an acid resistant film. A moisture barrier layer is formed on the acid resistant film of the aluminum foil layer.

An example of the method for manufacturing the packaging material for a battery of the present invention is as follows. First, a laminate in which an aluminum foil layer 3 having a base material layer 1, an adhesive layer 2, and a moisture barrier layers 6a and 6b formed on at least one surface is laminated in this order (hereinafter referred to as "laminate A"). There is also). Specifically, in the formation of the laminate A, first, a solution containing a resin for forming the moisture barrier layers 6a and 6b on one side or both sides of the aluminum foil layer 3 is subjected to a bar coating method, a roll coating method, or a gravure coating method. It can be formed by applying and drying by a method, a dipping method, or the like. Next, the adhesive used for forming the adhesive layer 2 is applied to the aluminum foil layer 3 on which the base material layer 1 or the moisture barrier layers 6a and 6b are formed on at least one surface by a gravure coating method or a roll coating. It can be carried out by a dry laminating method in which the aluminum foil layer 3 or the base material layer 1 is laminated and the adhesive layer 2 is cured after being applied and dried by a coating method such as a method.

Further, as described above, the moisture barrier layers 6a and 6b are formed by applying and drying a solution containing a resin on the surface of the aluminum foil layer by a bar coating method, a roll coating method, a gravure coating method, a dipping method or the like. can do. As a method for forming the moisture barrier layers 6a and 6b, a dipping method is preferable from the viewpoint of more reliably filling the pinholes. The resin for forming the moisture barrier layers 6a and 6b is as described above.

Next, the heat-weldable resin layer 4 is laminated on the aluminum foil layer 3 of the laminate A (in the case of having the moisture barrier layer 6b, the moisture barrier layer 6b; the same applies hereinafter). When the heat-weldable resin layer 4 is directly laminated on the aluminum foil layer 3, the resin components constituting the heat-weldable resin layer 4 are coated on the aluminum foil layer 3 of the laminated body A by a gravure coating method or a roll coating method. It may be applied by a method such as. When the adhesive layer 5 is provided between the aluminum foil layer 3 and the heat-weldable resin layer 4, for example, (1) the adhesive layer 5 and the heat-weldable resin layer are placed on the aluminum foil layer 3 of the laminated body A. A method of laminating 4 by co-extruding (co-extrusion laminating method), (2) Separately, a laminated body in which the adhesive layer 5 and the heat-weldable resin layer 4 are laminated is formed, and this is used as the aluminum foil layer of the laminated body A. A method of laminating on 3 by a thermal laminating method, (3) a method of laminating an adhesive for forming an adhesive layer 5 on an aluminum foil layer 3 of a laminated body A by an extrusion method, a method of coating with a solution and drying at a high temperature. Further, a method of laminating by a baking method or the like and laminating a heat-welding resin layer 4 having a sheet-like film formed in advance on the adhesive layer 5 by a thermal laminating method, (4) an aluminum foil layer 3 of the laminated body A and A method of laminating the laminate A and the heat-weldable resin layer 4 via the adhesive layer 5 while pouring the melted adhesive layer 5 between the heat-weldable resin layer 4 formed into a sheet in advance (sandwich). Laminating method) and the like.

When the surface coating layer is provided, the surface coating layer is laminated on the surface of the base material layer 1 opposite to the aluminum foil layer 3. The surface coating layer can be formed, for example, by applying the above resin forming the surface coating layer to the surface of the base material layer 1. The order of the step of laminating the aluminum foil layer 3 on the surface of the base material layer 1 and the step of laminating the surface coating layer on the surface of the base material layer 1 is not particularly limited. For example, after forming the surface coating layer on the surface of the base material layer 1, the aluminum foil layer 3 may be formed on the surface of the base material layer 1 opposite to the surface coating layer.

As described above, a surface coating layer provided as needed / a base material layer 1 / an adhesive layer 2 / an aluminum foil layer 3 (having a moisture barrier layer on at least one surface) / adhesion provided as needed. A laminate composed of the layer 5 / the heat-weldable resin layer 4 is formed. As described above, an acid resistant film 7 may be provided on at least one surface of the aluminum foil layer 3. In order to strengthen the adhesiveness of the adhesive layer 2 and the adhesive layer 5 provided as needed, it may be further subjected to heat treatment such as hot roll contact type, hot air type, near or far infrared type.

In the packaging material for batteries of the present invention, each layer constituting the laminated body improves or stabilizes film-forming property, laminating process, suitability for secondary processing (pouching, embossing) of the final product, etc., as necessary. Therefore, surface activation treatments such as corona treatment, blast treatment, oxidation treatment, and ozone treatment may be performed.

4. Uses of Battery Packaging Material The battery packaging material of the present invention is used as a packaging material for sealing and accommodating battery elements such as a positive electrode, a negative electrode, and an electrolyte. That is, the battery element can be housed in the package formed of the battery packaging material of the present invention.

Specifically, a battery element having at least a positive electrode, a negative electrode, and an electrolyte is connected to each of the positive electrode and the negative electrode by using a package formed of the battery packaging material of the present invention, and the metal terminals are outside. The battery element is coated so that a flange portion (a region where the heat-welding resin layers come into contact with each other) can be formed on the peripheral edge of the battery element, and the heat-welding resin layers of the flange portion are heat-sealed. By sealing, a battery using a battery packaging material is provided. When the battery element is housed using the battery packaging material of the present invention, the heat-weldable resin portion of the battery packaging material of the present invention is used so as to be inside (the surface in contact with the battery element).

The battery packaging material of the present invention may be used for either a primary battery or a secondary battery, but is preferably a secondary battery. The type of the secondary battery to which the packaging material for a battery of the present invention is applied is not particularly limited, and for example, a lithium ion battery, a lithium ion polymer battery, a lead livestock battery, a nickel / hydrogen livestock battery, and a nickel / cadmium livestock battery. , Nickel / iron livestock battery, nickel / zinc livestock battery, silver oxide / zinc livestock battery, metal air battery, polyvalent cation battery, condenser, capacitor and the like. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries can be mentioned as suitable application targets of the battery packaging material of the present invention.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the examples. The water vapor transmission rate of the resin is a value measured in accordance with JIS K 7129: 2008.

Examples 1-12
An aluminum foil coated on one side with a resin (shown in Table 1) forming the moisture barrier layer 6b was laminated on a base material layer (thickness 12 μm) by a dry laminating method. Specifically, a two-component urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to the surface of the aluminum foil on the side not coated with the moisture barrier layer 6b at a coating amount of ^{3 g / m 2.} The base material layer and the aluminum foil were laminated by the dry laminating method via the adhesive. Next, by carrying out an aging treatment, a laminate of a base material layer / adhesive layer / aluminum foil layer / moisture barrier layer 6b was produced. Further, the aluminum foil of Example 12 has one pinhole having a diameter of 0.1 mm.

Next, the surface of the moisture barrier layer 6b of the obtained laminate was subjected to corona treatment. Next, 10 μm of maleic anhydride-modified polypropylene (PPa; adhesive layer) and 14 μm of random polypropylene (PP; heat-welded resin layer) were co-extruded onto the corona-treated surface so that PPa was on the corona-treated surface side. An adhesive layer / heat-weldable resin layer was laminated on the moisture barrier layer 6b to obtain a packaging material for a battery. The laminated structure of each battery packaging material is as described later. ^{At the time of co-extrusion, air containing 20 g / m 3 of} ozone was blown onto the molten resin surface on the PPa surface side.
Adhesion with the aluminum foil layer with the corona-treated surface was promoted. The laminated structure of each battery packaging material is as described later.

Comparative Example 1-5 and Reference Example 1
An aluminum foil having an acid-resistant film formed on both sides was laminated on a base material layer (thickness 12 μm) by a dry laminating method. Specifically, a two-component urethane adhesive (polyol compound and aromatic isocyanate compound) was applied to the surface of the aluminum foil on the side not coated with the moisture barrier layer 6b at a coating amount of ^{3 g / m 2.} The base material layer and the aluminum foil were laminated by the dry laminating method via the adhesive. Next, by carrying out an aging treatment, a laminate of a base material layer / adhesive layer / acid-resistant film / aluminum foil layer / acid-resistant film was produced.

In the chemical conversion treatment to form an acid-resistant film on both sides of the aluminum foil, a treatment liquid consisting of a phenol resin, a chromium fluoride compound, and phosphoric acid is applied so that the coating amount of chromium is 10 mg / m ² (dry mass). , It was applied to both sides of the aluminum foil by the roll coating method and baked. Further, the aluminum foil of Comparative Example 5 has one pinhole having a diameter of 0.1 mm.

Next, the surface of the acid-resistant film of the obtained laminate was subjected to corona treatment. Next, in Comparative Examples 1, 2, 5 and Reference Example 1, 10 μm of maleic anhydride-modified polypropylene (PPa; adhesive layer) and 14 μm of random polypropylene (PP; heat-welded resin layer) were applied to the corona-treated surface of the laminated body. , PPa was co-extruded so as to be on the corona-treated surface side, and an adhesive layer / heat-weldable resin layer was laminated on the acid-resistant film of the aluminum foil layer to obtain a packaging material for a battery. Further, in Comparative Examples 3 and 4, a random polypropylene film (25 μm, heat-welded resin layer) was adhered to the corona-treated surface of the laminated body via an adhesive layer (2 μm) to obtain a packaging material for a battery. In Comparative Example 3, an adhesive containing maleic anhydride-modified polypropylene and an epoxy resin was used as the adhesive layer. In Comparative Example 4, an adhesive containing a polyester resin and a urethane resin was used as the adhesive layer. The laminated structure of each battery packaging material is as described later.

Example 13
An aluminum foil having an acid resistant film formed on both sides was prepared. The chemical conversion treatment for forming an acid-resistant film on both sides of the aluminum foil is the same as in Comparative Example 1-5 and Reference Example 1. Next, one surface that had undergone chemical conversion treatment was coated with a resin (shown in Table 1) that forms the moisture barrier layer 6a. Next, the surface of the aluminum foil coated with the moisture barrier layer 6a is subjected to corona treatment, and a two-component urethane adhesive (polyol compound and aromatic isocyanate compound) is applied at a coating amount of ^{3 g / m 2.} Dry laminate the substrate layer and aluminum foil via the adhesive

Laminated by the G method. Next, by carrying out an aging treatment, a laminate of a base material layer / adhesive layer / moisture barrier layer 6a / acid-resistant film / aluminum foil layer / acid-resistant film was produced.

Next, 10 μm of maleic anhydride-modified polypropylene (PPa; adhesive layer) and random polypropylene (PP; heat-welding resin layer) were placed on the surface of the acid-resistant film on the side where the base material layer of the obtained laminate was not laminated. 14 μm was co-extruded so that PPa was on the acid-resistant film side, and an adhesive layer / heat-weldable resin layer was laminated on the acid-resistant film of the aluminum foil layer to obtain a packaging material for a battery. The laminated structure of each battery packaging material is as described later.

The laminated structure of the battery packaging material obtained in Example 1-13, Reference Example 1, and Comparative Example 1-5 is shown below. Specifically, the resins used in Examples and Comparative Examples are as follows. The water vapor transmission rate of the resin is a value measured in an environment of a temperature of 40 ° C., a relative humidity of 90% RH, and 1 atm when the resin is a film having a thickness of 50 μm.

Ny: Nylon film PBT: Polybutylene terephthalate film PCTFE: Polychlorotrifluoroethylene Melting point 210 ° C, water vapor permeability 0.2 g / m ² · day, specific gravity 2.15
ETFE: Tetrafluoroethylene-ethylene copolymer Melting point 260 ° C, water vapor transmission rate 3.0 g / m ² · day, specific density 1.73
PFA: Tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer Melting point 305 ° C, water vapor transmission rate 1.3 g / m ² · day, specific density 2.15
FEP: Tetrafluoroethylene-hexafluoropropylene copolymer Melting point 270 ° C., water vapor transmission rate 0.6 g / m ² · day, specific gravity 2.15
PPa: Maleic anhydride-modified polypropylene Melting point 140 ° C
PP: Random polypropylene Melting point 140 ° C
CPP: unstretched polypropylene Melting point 140 ° C

(Example 1)
Ny (12 μm) / adhesive layer (3 μm) / aluminum foil layer (9 μm) / PCTFE (0.1 μm) / PPa (10 μm) / PP (14 μm)
(Example 2)
Ny (12 μm) / adhesive layer (3 μm) / aluminum foil layer (15 μm) / PCTFE (0.1 μm) / PPa (10 μm) / PP (14 μm)
(Example 3)
PBT (12 μm) / adhesive layer (3 μm) / aluminum foil layer (9 μm) / PCTFE (0.1 μm) / PPa (10 μm) / PP (14 μm)
(Example 4)
Ny (12 μm) / adhesive layer (3 μm) / aluminum foil layer (9 μm) / ETFE (0.1 μm) / PPa (10 μm) / PP (14 μm)
(Example 5)
Ny (12 μm) / adhesive layer (3 μm) / aluminum foil layer (9 μm) / PFA (0.1 μm) / PPa (10 μm) / PP (14 μm)
(Example 6)
Ny (12 μm) / adhesive layer (3 μm) / aluminum foil layer (9 μm) / FEP (0.1 μm) / PPa (10 μm) / PP (14 μm)
(Example 7)
Ny (12 μm) / adhesive layer (3 μm) / aluminum foil layer (9 μm) / PCTFE (0.3 μm) / PPa (10 μm) / PP (14 μm)
(Example 8)
Ny (12 μm) / adhesive layer (3 μm) / aluminum foil layer (9 μm) / PCTFE (0.6 μm) / PPa (10 μm) / PP (14 μm)
(Example 9)
Ny (12 μm) / adhesive layer (3 μm) / aluminum foil layer (35 μm) / PCTFE (0.1 μm) / PPa (10 μm) / PP (14 μm)
(Example 10)
Ny (25 μm) / adhesive layer (3 μm) / aluminum foil layer (9 μm) / PCTFE (0.1 μm) / PPa (10 μm) / PP (14 μm)
(Example 11)
Ny (12 μm) / adhesive layer (3 μm) / aluminum foil layer (9 μm) / PCTFE (0.1 μm) / PPa (23 μm) / PP (23 μm)
(Example 12)
Ny (12 μm) / adhesive layer (3 μm) / aluminum foil layer (35 μm) / PCTFE (0.1 μm) / PPa (10 μm) / PP (14 μm)
(Example 13)
Ny (12 μm) / Adhesive layer (3 μm) / PCTFE (0.1 μm) / Acid resistant film (0.05 μm) / Aluminum foil layer (9 μm) / Acid resistant film (0.05 μm) / PPa (10 μm) / PP (14 μm)

(Comparative Example 1)
Ny (12 μm) / Adhesive layer (3 μm) / Acid resistant film (0.05 μm) / Aluminum foil layer (6 μm) / Acid resistant film (0.05 μm) / PPa (10 μm) / PP (14 μm) (Comparative Example 2) )
Ny (12 μm) / Adhesive layer (3 μm) / Acid resistant film (0.05 μm) / Aluminum foil layer (9 μm) / Acid resistant film (0.05 μm) / PPa (10 μm) / PP (14 μm) (Comparative Example 3) )
Ny (12 μm) / Adhesive layer (3 μm) / Acid resistant film (0.05 μm) / Aluminum foil layer (9 μm) / Acid resistant film (0.05 μm) / PPa + Epoxy resin (2 μm) / Unstretched PP film (25 μm) )
(Comparative Example 4)
Ny (12 μm) / Adhesive layer (3 μm) / Acid resistant film (0.05 μm) / Aluminum foil layer (9 μm) / Acid resistant film (0.05 μm) / Polyester + Urethane resin (2 μm) / Unstretched PP film ( 25 μm)
(Comparative Example 5)
Ny (12 μm) / Adhesive layer (3 μm) / Acid resistant film (0.05 μm) / Aluminum foil layer (35 μm) / Acid resistant film (0.05 μm) / PPa (10 μm) / PP (14 μm)
(Reference example 1)
Ny (12 μm) / Adhesive layer (3 μm) / Acid resistant film (0.05 μm) / Aluminum foil layer (35 μm) / Acid resistant film (0.05 μm) / PPa (10 μm) / PP (14 μm)

<Evaluation of moldability>
Each battery packaging material obtained above was cut into a rectangle of 80 mm × 120 mm to prepare a sample. Using a molding die (female mold) having a diameter of 30 mm × 50 mm and a corresponding molding die (male mold), this sample was pressed from a molding depth of 0.5 mm at a pressing pressure of 0.4 MPa to 0. Cold forming was performed on each of 10 samples by changing the forming depth in units of 5 mm. For the sample after cold forming, the deepest forming depth at which wrinkles, pinholes, and cracks did not occur in all 10 samples was defined as the limit forming depth of the sample. From this limit molding depth, the moldability of the battery packaging material was evaluated according to the following criteria. The results are shown in Tables 1 and 2.
A: Limit molding depth over 5.0 mm B: Limit molding depth over 4.0, 5.0 mm or less C: Limit molding depth over 3.0, 4.0 mm or less D: Limit molding depth 3.0 mm or less

<Evaluation of electrolyte resistance>
1 g of electrolytic solution (ethylene carbonate, diethyl carbonate, dimethyl carbonate (1: 1: 1) so as to be _{1 M LiPF 6) in} the concave portion of the sample after the above cold molding was performed at a molding depth of 3.0 mm. And another packaging material for batteries (unmolded) was layered from above the recesses so that the heat-weldable resin layers faced each other, and the peripheral edge was heat-sealed. The conditions for heat sealing were 190 ° C. and a surface pressure of 1.0 MPa for 3 seconds. This was stored at 85 ° C. for 1 day, opened, washed with water, wiped with water, and a strip-shaped sample having a width of 15 mm was cut out from the recess. Next, the peel strength between the aluminum foil layer and the heat-weldable resin layer of the sample was measured by 180 degree peeling at a tensile speed of 50 mm / min. The results are shown in Tables 1 and 2.
A: Peeling strength over 4N / 15mm B: Peeling strength over 2N / 15mm, 4N / 15mm or less C: Peeling strength over 2N / 15mm

<Evaluation of water vapor barrier property>
The packaging material for each battery obtained above is cut into strips of 120 mm x 120 mm, the sealant side is overlapped and folded in half, and the long side facing the folded side is heat-sealed with a width of 7 mm (seal condition: seal temperature). After 190 ° C., surface pressure 1.0 MPa, sealing time 3.0 seconds), trimming to a width of 3 mm was performed. Next, one of the two sides of the folded side is heat-sealed with a width of 10 mm (sealing conditions: sealing temperature 190 ° C., surface pressure 2.0 MPa, sealing time 3.0 seconds) to form a pouch, and a solution (ethylene carbonate) is formed. : Diethyl carbonate: dimethyl carbonate = 1: 1: 1) is injected into the pouch, and then the remaining short side to be opened is heat-sealed with a width of 10 mm (seal conditions: seal temperature 190 ° C, surface pressure 2.0 MPa, seal). The time was 3.0 seconds) to prepare an enclosure (bag). Next, the pouch was stored in an environment with a relative humidity of 90% and a temperature of 60 ° C. for 7 days, and then the amount of water contained in the electrolytic solution was measured by the Karl Fischer method. The results are shown in Tables 1 and 2 based on the following evaluation criteria.
A: 20ppm or less B: 20ppm or more, 30ppm or less C: 30ppm or more, 50ppm or less D: 50ppm or less

* 1 In Table 1, one pinhole having a diameter of 0.1 mm is formed in the aluminum foils of Example 12 and Comparative Example 5.
* 2 On the other hand, the aluminum foils of Example 9 and Reference Example 1 are large in thickness and do not have pinholes.

In Tables 1 and 2, AL is an aluminum foil layer, Ny is nylon, PBT is polybutylene terephthalate, PCTFE is polychlorotrifluoroethylene, ETFE is a tetrafluoroethylene-ethylene copolymer, and PFA is tetrafluoroethylene-per. Fluoroalkyl vinyl ether copolymer, FEP means tetrafluoroethylene-hexafluoropropylene copolymer, PPa means maleic anhydride-modified polypropylene, PP means polypropylene, and CPP means unstretched polypropylene. Further, in Tables 1 and 2, the numerical value attached to the back of each layer means the thickness (μm), and for example, “Ny12” means “nylon with a thickness of 12 μm”.

As is clear from the results shown in Table 1, in the battery packaging material of Example 1-13 in which the moisture barrier layer is provided on the surface of the aluminum foil layer, the water vapor barrier property, moldability, and electrolytic solution resistance are improved. It was excellent. Specifically, in the battery packaging materials of Examples 1-8, 10, 11 and 13, although the thickness of the aluminum foil layer is very thin, there is a high possibility that pinholes are present. Since the moisture barrier layer is provided, it is excellent in water vapor barrier property, moldability, and electrolytic solution resistance. On the other hand, in the battery packaging material of Comparative Example 1-4 in which the moisture barrier layer was not provided, it is considered that pinholes are present because the thickness of the aluminum foil layer is very thin, and the water vapor barrier property is remarkably poor. rice field. Further, Example 12 in which the moisture barrier layer is provided on the thick aluminum foil having pinholes is the same as in Example 9 and Reference Example 1 using the thick aluminum foil having no pinholes. It had excellent water vapor barrier properties. On the other hand, in Comparative Example 5 in which the moisture barrier layer was not provided on the thick aluminum foil having pinholes, the water vapor barrier property was remarkably poor.

1 Base material layer 2 Adhesive layer 3 Aluminum foil layer 4 Heat-welding resin layer 5 Adhesive layers 6a, 6b Moisture barrier layer 7 Acid-resistant film

Claims (10)

It is composed of a laminate having at least a base material layer, an adhesive layer, an aluminum foil layer, and a heat-weldable resin layer in this order.
A battery packaging material comprising a moisture barrier layer on at least one side of the aluminum foil layer. The battery packaging material according to claim 1, wherein the total thickness of the laminate is 55 μm or less. The packaging material for a battery according to claim 1 or 2, wherein the moisture barrier layer is provided between the aluminum foil layer and the heat-weldable resin layer. The aluminum foil layer has pinholes and
The battery packaging material according to any one of claims 1 to 3, wherein the pinhole is filled with the moisture barrier layer. The battery packaging material according to any one of claims 1 to 4, wherein the moisture barrier layer has a thickness of 1 μm or less. The battery packaging material according to any one of claims 1 to 5, wherein the moisture barrier layer is formed of at least one selected from the group consisting of fluororesin, polyethylene naphthalate, and polyarylate. The packaging material for a battery according to any one of claims 1 to 6, wherein the thickness of the aluminum foil layer is 20 μm or less. The battery packaging material according to any one of claims 1 to 7, which is a packaging material for a secondary battery. A battery in which a battery element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the battery packaging material according to any one of claims 1 to 8. At least, a step of laminating the base material layer, the adhesive layer, the aluminum foil layer, and the heat-welding resin layer in this order to obtain a laminate.
A step of covering at least one side of the aluminum foil layer with a moisture barrier layer,
A method of manufacturing packaging materials for batteries.

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