JP2017084787A - Battery-packaging material, battery, method for manufacturing battery-packaging material, and aluminum alloy foil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery-packaging material which is hard to form a pin hole or crack in molding, and superior in moldability.SOLUTION: A battery-packaging material comprises at least an aluminum alloy foil layer 3. With random 100 second phase grains 32 located within a field of view of an optical microscope in a cross section of the aluminum alloy foil layer in a thickness direction, an average of diameters y of the 20 second phase grains of higher rank in a descending order of the diameters y is 5.0 μm or less, provided that the diameter y is a straight line distance connecting between leftmost and rightmost ends of each second phase grain in a direction perpendicular to the thickness direction.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a battery packaging material, a battery, a method for producing a battery packaging material, and an aluminum alloy foil.

  Conventionally, various types of batteries have been developed. In any battery, a packaging material is an indispensable member for sealing battery elements such as electrodes and electrolytes. Conventionally, metal packaging materials have been frequently used as battery packaging.

  On the other hand, in recent years, with the improvement in performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., batteries are required to have various shapes, and are also required to be thinner and lighter. However, metal battery packaging materials that have been widely used in the past have the disadvantages that it is difficult to follow the diversification of shapes and that there is a limit to weight reduction.

  Therefore, in recent years, as a battery packaging material that can be easily processed into various shapes and can be thinned and lightened, a film-like structure in which a base material / aluminum alloy foil layer / a heat-fusible resin layer are sequentially laminated. Laminates have been proposed.

  In such battery packaging materials, generally, recesses are formed by cold forming, and battery elements such as electrodes and electrolytes are arranged in the spaces formed by the recesses, and the heat-fusible resin layers Is heat-sealed to obtain a battery in which the battery element is accommodated in the battery packaging material. However, such a film-shaped packaging material has a drawback that it is thinner than a metal packaging material and easily causes pinholes and cracks during molding. When pinholes or cracks occur in battery packaging materials, the electrolyte can penetrate into the aluminum alloy foil layer to form metal deposits, which can result in short circuits. It is indispensable to provide the battery packaging material with a characteristic that does not easily cause pinholes during molding, that is, excellent moldability.

  For example, Patent Document 1 discloses that in the laminated packaging material including an inner layer made of a resin film, a first adhesive layer, an aluminum alloy foil layer, a second adhesive layer, and an outer layer made of a resin film, the first adhesive By forming at least one of the agent layer and the second adhesive layer with an adhesive composition containing a resin having an active hydrogen group in the side chain, a polyfunctional isocyanate, and a polyfunctional amine compound, It is disclosed that a highly reliable packaging material can be obtained.

JP 2008-287971 A

  In recent years, with the demand for smaller and thinner batteries, there has been a demand for further thinning of battery packaging materials. Accordingly, there is a demand for further reduction in the thickness of the aluminum alloy foil layer laminated on the battery packaging material. However, when the thickness of the aluminum alloy foil layer is reduced, there is a problem that pinholes and cracks are likely to occur in the aluminum alloy foil layer during molding.

  Under such circumstances, the present invention provides a battery packaging material that can effectively suppress the occurrence of pinholes and cracks in the aluminum alloy foil layer during the molding of the battery packaging material. Main purpose.

  The present inventor has intensively studied to solve the above problems. As a result, at least in the battery packaging material provided with the aluminum alloy foil layer, in the cross section in the thickness direction of the aluminum alloy foil layer, for each of the 100 second phase particles in the field of view of the optical microscope, the individual second phase particles When the distance from the leftmost end of the phase particles to the rightmost end is the diameter y, the average of the diameters y of the top 20 second phase particles in the descending order of the diameter y is 5.0 μm or less. As a result, the inventors have found that pinholes and cracks are less likely to occur during molding, and the battery packaging material has excellent moldability. The present invention has been completed by further studies based on these findings.

That is, this invention provides the battery packaging material and battery of the aspect hung up below.
Item 1. At least a battery packaging material provided with an aluminum alloy foil layer,
In the cross section in the thickness direction of the aluminum alloy foil layer, for any 100 second phase particles in the field of view of the optical microscope, the leftmost end in the direction perpendicular to the thickness direction of the individual second phase particles, Is a battery for which the average of the diameter y of the top 20 second phase particles is 5.0 μm or less when the diameter y is the linear distance connecting the rightmost end in the vertical direction. Packaging material.
Item 2. In the cross section in the thickness direction of the aluminum alloy foil layer, for any 100 aluminum alloy crystal grains located within the field of view of the scanning electron microscope, the leftmost end in the direction perpendicular to the thickness direction of the individual crystal grains, The average crystal grain size, which is an average value of the maximum diameter x of the 100 crystal grains, is 10.0 μm or less, where the maximum diameter x is a linear distance connecting the thickness direction and the rightmost end in the vertical direction. Item 4. The battery packaging material according to Item 1.
Item 3. Item 1 or 2 wherein the aluminum alloy constituting the aluminum alloy foil layer includes 0.7% by mass or more and 2.5% by mass or less of Fe, 0.05% by mass or less of Cu, and 0.30% by mass or less of Si. 2. Battery packaging material according to 2.
Item 4. Item 4. The battery packaging material according to any one of Items 1 to 3, wherein the aluminum alloy foil layer has an acid-resistant film on at least one surface thereof.
Item 5. Item 5. The battery packaging material according to any one of Items 1 to 4, which is a packaging material for a secondary battery.
Item 6. A battery in which a battery element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a container formed of the battery packaging material according to any one of Items 1 to 5.
Item 7. At least a base material layer, an aluminum alloy foil layer, and a heat-fusible resin layer are provided so as to be laminated in this order to obtain a laminate.
As the aluminum alloy foil layer, in the cross section in the thickness direction of the aluminum alloy foil layer, any 100 second phase particles in the field of view of the optical microscope are perpendicular to the thickness direction of the individual second phase particles. When the linear distance connecting the leftmost end and the rightmost end in the direction perpendicular to the thickness direction is defined as the diameter y, the average of the diameters y of the top 20 second phase particles in the descending order of the diameter y is 5. The manufacturing method of the packaging material for batteries using what is 0 micrometer or less.
Item 8. An aluminum alloy foil for use in battery packaging materials,
In the cross section in the thickness direction of the aluminum alloy foil, with respect to any 100 second phase particles in the field of view of the optical microscope, the leftmost end in the direction perpendicular to the thickness direction of the individual second phase particles and the thickness direction are A battery packaging in which the average of the diameters y of the top 20 second phase particles in the descending order of the diameter y is 5.0 μm or less, where the linear distance connecting the rightmost end in the vertical direction is the diameter y. Aluminum alloy foil for use in materials.
Item 9. In the cross section in the thickness direction of the aluminum alloy foil, with respect to any 100 aluminum alloy crystal grains located within the field of view of the scanning electron microscope, the leftmost end in the direction perpendicular to the thickness direction of the individual crystal grains, and When the straight line distance connecting the rightmost end in the vertical direction with the thickness direction is the maximum diameter x, the average crystal grain size, which is an average value of the maximum diameter x of the 100 crystal grains, is 10.0 μm or less. Item 9. An aluminum alloy foil for use in a battery packaging material according to Item 8.
Item 10. Item 8 or 9 wherein the aluminum alloy constituting the aluminum alloy foil contains 0.7% by mass or more and 2.5% by mass or less of Fe, 0.05% by mass or less of Cu, and 0.30% by mass or less of Si. Aluminum alloy foil for use in the battery packaging material described in 1.
Item 11. Item 11. The aluminum alloy foil for use in a battery packaging material according to any one of Items 8 to 10, wherein the aluminum alloy foil has an acid-resistant film on at least one surface thereof.

  According to the present invention, it is possible to provide a battery packaging material that is less likely to cause pinholes and cracks during molding and has excellent moldability. Since the battery packaging material of the present invention has excellent moldability, it can also contribute to the improvement of productivity.

It is a figure which shows an example of the cross-section of the packaging material for batteries of this invention. It is a figure which shows an example of the cross-section of the packaging material for batteries of this invention. It is a schematic diagram which shows the crystal grain and 2nd phase particle in the cross section of the thickness direction of an aluminum alloy foil layer.

  The battery packaging material of the present invention includes at least an aluminum alloy foil layer, and in the cross section in the thickness direction of the aluminum alloy foil layer, any 100 second phase particles in the field of view of the optical microscope are individually provided. When the diameter y is a linear distance connecting the leftmost end in the vertical direction with respect to the thickness direction of the second phase particles and the rightmost end in the vertical direction with respect to the thickness direction, the top 20 of the top 20 The average of the diameter y of the two-phase particles is 5.0 μm or less. Hereinafter, the battery packaging material of the present invention will be described in detail.

  In the present specification, the numerical range indicated by “to” means “above” or “below”, except for the portions specified as “above” or “below”. For example, the notation of 2 to 15 mm means 2 mm or more and 15 mm or less.

1. Laminated structure of battery packaging material The battery packaging material of the present invention comprises at least an aluminum alloy foil layer 3 as shown in FIG. The battery packaging material of the present invention may be, for example, a laminate having a base material layer 1, an aluminum alloy foil layer 3, and a heat-fusible resin layer 4 in this order, as shown in FIG. When the battery packaging material of the present invention is such a laminate, the base material layer 1 is the outermost layer side, and the heat-fusible resin layer 4 is the innermost layer. That is, when the battery is assembled, the battery element is sealed by heat-sealing the heat-fusible resin layers 4 positioned at the periphery of the battery element to seal the battery element.

  As shown in FIG. 1, the battery packaging material of the present invention is provided with an adhesive layer 2 between the base material layer 1 and the aluminum alloy foil layer 3 as necessary for the purpose of enhancing the adhesiveness thereof. It may be done. In addition, as shown in FIG. 2, the battery packaging material of the present invention is bonded between the aluminum alloy foil layer 3 and the heat-fusible resin layer 4 as necessary for the purpose of improving the adhesion. A layer 5 may be provided.

  The total thickness of the laminate constituting the battery packaging material of the present invention is not particularly limited, but the battery packaging material has excellent moldability while reducing the thickness of the battery packaging material to increase the energy density of the battery. In view of the above, for example, 200 μm or less, preferably 180 μm or less, more preferably about 40 to 155 μm, and still more preferably about 40 to 90 μm.

2. Each layer forming the battery packaging material [base material layer 1]
In the battery packaging material of the present invention, the base material layer 1 is a layer provided as necessary, and is a layer located on the outermost layer side. The material for forming the base material layer 1 is not particularly limited as long as it has insulating properties. Examples of the material for forming the base material layer 1 include polyester, polyamide, epoxy resin, acrylic resin, fluorine resin, polyurethane, silicon resin, phenol resin, polyetherimide, polyimide, and a mixture or copolymer thereof. Can be mentioned.

  Specific examples of the polyester include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, copolymerized polyester mainly composed of ethylene terephthalate, butylene terephthalate as a repeating unit. Examples thereof include a copolymer polyester mainly used. The copolymer polyester mainly composed of ethylene terephthalate is a copolymer polyester that polymerizes with ethylene isophthalate mainly composed of ethylene terephthalate (hereinafter, polyethylene (terephthalate / isophthalate)). Abbreviated), polyethylene (terephthalate / isophthalate), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate) And polyethylene (terephthalate / decanedicarboxylate). In addition, as a copolymer polyester mainly composed of butylene terephthalate as a repeating unit, specifically, a copolymer polyester that polymerizes with butylene isophthalate having butylene terephthalate as a repeating unit (hereinafter referred to as polybutylene (terephthalate / isophthalate)). For example), polybutylene (terephthalate / adipate), polybutylene (terephthalate / sebacate), polybutylene (terephthalate / decanedicarboxylate), polybutylene naphthalate and the like. These polyesters may be used individually by 1 type, and may be used in combination of 2 or more type. Polyester has the advantage of being excellent in electrolytic solution resistance and less likely to cause whitening due to the adhesion of the electrolytic solution, and is suitably used as a material for forming the base material layer 1.

  Specific examples of polyamides include aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and a copolymer of nylon 6 and nylon 66; terephthalic acid and / or isophthalic acid Nylon 6I, Nylon 6T, Nylon 6IT, Nylon 6I6T (I represents isophthalic acid, T represents terephthalic acid) and the like, and polymetaxylylene azide Polyamide containing aromatics such as Pamide (MXD6); Alicyclic polyamides such as Polyaminomethylcyclohexyl Adipamide (PACM6); and Lactam components and isocyanate components such as 4,4′-diphenylmethane-diisocyanate are copolymerized Polyamide, copolymer Polyester amide copolymer and polyether ester amide copolymer is a copolymer of a polyamide and a polyester and polyalkylene ether glycol; copolymers thereof, and the like. These polyamides may be used individually by 1 type, and may be used in combination of 2 or more type. The stretched polyamide film is excellent in stretchability, can prevent whitening due to resin cracking of the base material layer 1 during molding, and is suitably used as a material for forming the base material layer 1.

  The base material layer 1 may be formed of a uniaxially or biaxially stretched resin film, or may be formed of an unstretched resin film. Among them, a uniaxially or biaxially stretched resin film, in particular, a biaxially stretched resin film has improved heat resistance by orientation crystallization, and thus is suitably used as the base material layer 1. Moreover, the base material layer 1 may be formed by coating the above-mentioned raw material on the aluminum alloy foil layer 3.

  Among these, as a resin film which forms the base material layer 1, Preferably nylon and polyester, More preferably, biaxially stretched nylon, biaxially stretched polyester, Most preferably, biaxially stretched nylon is mentioned.

  The base material layer 1 can also be laminated with at least one of resin films and coatings of different materials in order to improve pinhole resistance and insulation when used as a battery package. Specific examples include a multilayer structure in which a polyester film and a nylon film are laminated, and a multilayer structure in which a biaxially stretched polyester and a biaxially stretched nylon are laminated. When making the base material layer 1 into a multilayer structure, each resin film may be adhere | attached through an adhesive agent, and may be laminated | stacked directly without an adhesive agent. In the case of bonding without using an adhesive, for example, a method of bonding in a hot-melt state such as a co-extrusion lamination method, a sandwich lamination method, or a thermal lamination method can be mentioned. Moreover, when making it adhere | attach through an adhesive agent, the adhesive agent to be used may be a two-component curable adhesive, or a one-component curable adhesive. Furthermore, the adhesive mechanism of the adhesive is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a heat melting type, a hot pressure type, an electron beam curable type, an ultraviolet curable type, and the like. As an adhesive component, polyester resin, polyether resin, polyurethane resin, epoxy resin, phenol resin resin, polyamide resin, polyolefin resin, polyvinyl acetate resin, cellulose resin, (meth) acrylic resin Resins, polyimide resins, amino resins, rubbers, and silicon resins can be used.

  As thickness of the base material layer 1, Preferably it is 25 micrometers or less, More preferably, about 8-25 micrometers is mentioned.

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

  The adhesive layer 2 is formed of an adhesive capable of bonding the base material layer 1 and the aluminum alloy foil layer 3. The adhesive used for forming the adhesive layer 2 may be a two-component curable adhesive or a one-component curable adhesive. Furthermore, the bonding mechanism of the adhesive used for forming the adhesive layer 2 is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a heat melting type, a hot pressure type, and the like.

  Specific examples of adhesive components 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 copolyester; Polyether adhesive; Polyurethane adhesive; Epoxy resin; Phenol resin resin; Polyamide resin such as nylon 6, nylon 66, nylon 12, copolymer polyamide; polyolefin, carboxylic acid modified polyolefin, metal modified polyolefin, etc. Polyolefin resins, polyvinyl acetate resins, cellulose adhesives, (meth) acrylic resins, polyimide resins, urea resins, melamine resins and other amino resins, chloroprene rubber, nitrile rubber, steel - down rubber such as butadiene rubber, silicone-based resins. These adhesive components may be used individually by 1 type, and may be used in combination of 2 or more type. Among these adhesive components, a polyurethane adhesive is preferable.

  The thickness of the adhesive layer 2 is not particularly limited as long as the battery packaging material satisfies the above physical properties while exhibiting the function as the adhesive layer. For example, the thickness is about 1 to 10 μm, preferably about 2 to 5 μm. It is done.

[Aluminum alloy foil layer 3]
In the battery packaging material, the aluminum alloy foil layer 3 is a layer that functions as a barrier layer for preventing water vapor, oxygen, light, and the like from entering the battery, in addition to improving the strength of the battery packaging material.

  As described above, in recent years, with the demand for smaller and thinner batteries, there has been a demand for further thinning of battery packaging materials. In connection with this, further thickness reduction is calculated | required also with respect to the thickness of the aluminum alloy foil layer laminated | stacked on the packaging material for batteries. In the present invention, the thickness of the entire battery packaging material can be set as described above. For this reason, the energy density of a battery can be raised effectively.

  In the present invention, from the viewpoint of making the battery packaging material excellent in moldability and appearance after molding while further reducing the thickness of the battery packaging material to increase the energy density of the battery, an aluminum alloy The thickness of the foil layer is preferably 100 μm or less, more preferably 80 μm or less, further preferably 50 μm or less, still more preferably 35 μm or less, further 30 μm or less, further about 15 to 30 μm, further about 15 to 25 μm, Especially about 15-20 micrometers is mentioned.

  As described above, when the thickness of the aluminum alloy foil layer is reduced to, for example, about 100 μm, further to about 30 μm, it becomes clear that pinholes and cracks are particularly likely to occur in the aluminum alloy foil layer when the battery packaging material is formed. It was. Furthermore, as a result of repeated studies by the present inventor, the thickness of the aluminum alloy foil layer is reduced to, for example, about 100 μm, and further to about 30 μm. When it became thin, it became clear that the frequency of occurrence of pinholes and cracks during molding was remarkably increased.

  On the other hand, in the battery packaging material of the present invention, each of the 100 second phase particles 32 in the field of view of the optical microscope in the cross section in the thickness direction of the aluminum alloy foil layer 3 is an individual second phase. When the diameter y is a linear distance connecting the leftmost end in the vertical direction with the thickness direction of the particle 32 and the rightmost end in the vertical direction with the thickness direction, the top 20 second phase particles in descending order of the diameter y. Since the average of the diameter y of 32 is 5.0 μm or less, the battery packaging material is formed even though a very thin aluminum alloy foil having a thickness of, for example, about 100 μm or even 30 μm or less is laminated. Occasionally pinholes and cracks hardly occur and it has excellent formability. Furthermore, in the battery packaging material of the present invention, the average diameter y of the second phase particles 32 in the aluminum alloy foil layer 3 is 5.0 μm or less, so that the thickness of the aluminum alloy foil layer 3 is, for example, about 100 μm, Furthermore, the total thickness of the battery packaging material is 30 μm or less, and even when it is as thin as the above-described thickness, for example, pinholes and cracks hardly occur during molding, and excellent moldability is provided.

  In the present invention, the average diameter y of the second phase particles 32 in the aluminum alloy foil layer 3 may be 5.0 μm or less, but from the viewpoint of further improving the formability, the average of the diameter y is 1 The thickness is more preferably about 0.0 to 4.0 μm, and further preferably about 1.0 to 2.0 μm. Since FIG. 3 is a schematic diagram, drawing is omitted and 100 second phase particles 32 are not drawn.

  In the present invention, the second phase particles contained in the aluminum alloy layer refer to intermetallic compound particles present in the aluminum alloy, and are precipitated when performing a crystallization phase or homogenization treatment or annealing separated by rolling. Phase particles.

  When a cross section in the thickness direction of the aluminum alloy foil layer is observed with a scanning electron microscope (SEM), the crystal grains usually draw a boundary line in contact with a plurality of crystals. On the other hand, the second phase particles usually have a single crystal at the boundary line. Further, since the crystal grains and the second phase particles have different phases, they have a feature that the colors are different on the SEM image. Furthermore, when the cross section in the thickness direction of the aluminum alloy foil layer is observed with an optical microscope, only the second phase particles appear black due to the phase difference between the crystal grains and the second phase particles. It becomes easy.

  The average crystal grain size in the aluminum alloy foil layer 3 is preferably 10.0 μm or less, more preferably about 1.0 to 7.0 μm, and still more preferably 1.0 to 3.mu. About 2 μm may be mentioned. When the average crystal grain size in the aluminum alloy foil layer 3 is 10.0 μm or less and the diameter y of the second phase particles 32 is the above value, the moldability of the battery packaging material is further enhanced. be able to.

  In the present invention, the average crystal grain size in the aluminum alloy foil layer is obtained by observing a cross section in the thickness direction of the aluminum alloy foil layer with a scanning electron microscope (SEM), and regarding the crystal grains 31 of 100 aluminum alloys located in the field of view. As shown in the schematic diagram of FIG. 3, when the maximum diameter x is a linear distance connecting the leftmost end in the vertical direction with respect to the thickness direction of each crystal grain and the rightmost end in the vertical direction with respect to the thickness direction, It means the average value of the maximum diameter x of 100 crystal grains. Since FIG. 3 is a schematic diagram, drawing is omitted and 100 crystal grains 31 are not drawn.

  The composition of the aluminum alloy constituting the aluminum alloy foil layer 3 is not particularly limited as long as the average diameter y of the second phase particles 32 is 5.0 μm or less, but the viewpoint of further improving the moldability of the battery packaging material. Therefore, the aluminum alloy preferably contains 0.7 to 2.5 mass% Fe, 0.05 mass% or less Cu, and 0.30 mass% or less Si.

  Specific examples of the aluminum alloy forming the aluminum alloy foil layer 3 include, for example, annealed aluminum (JIS H4160 A8021H-O, JIS H4160 A8079H-O, JIS H4000: 2014 A8021P-O, JIS H4000: 2014 A8079P- Examples thereof include soft aluminum alloys such as O). However, since the diameter and average crystal grain size of the above-mentioned second phase particles vary depending not only on the composition of the aluminum alloy but also on the processing method of the aluminum alloy foil layer, for example, the above-mentioned thickness only with the composition specified in JIS. Does not satisfy the relationship.

  The diameter of the second phase particles and the average crystal grain size of the aluminum alloy foil layer can be adjusted by a known method. For example, the method of adjusting the firing temperature, rolling conditions, etc. at the time of manufacturing aluminum alloy foil is mentioned. In the following, as a method for setting the diameter of the second phase particles and the average crystal grain size of the aluminum alloy foil layer 3 to the above values, an Al—Fe based aluminum foil is shown as an example.

(Example of formation method of Al-Fe-based aluminum foil)
The Al—Fe-based aluminum foil in which the diameter of the second phase particles and the average crystal grain size in the aluminum alloy foil layer are the above values is melted, cast, slab, face-cut, homogenized (homogenized), hot-rolled, It can manufacture by performing each process, such as cold rolling, intermediate annealing, cold rolling, foil rolling, and final annealing. In the melting step and the casting step, for example, JIS standard A8079H-O is melted to produce an ingot. In the hot rolling process, the homogenized alloy material is rolled in a high temperature environment. The hot rolling temperature of the alloy material in this step is preferably 280 to 300 ° C. Subsequently, in the cold rolling process, the hot-rolled alloy material is cold-rolled and thinly extended. The cold rolling temperature of the alloy material in this step is preferably set to 110 to 240 ° C. Further, in the intermediate annealing step, strain inside the alloy material after cold rolling is removed by heat treatment, the structure is softened, and expanded. Improve ductility. The treatment temperature in this step is preferably 380 to 400 ° C, and particularly preferably 390 ° C. The treatment time is preferably 1.5 to 2.5 hours. By appropriately adjusting these conditions, the diameter and average crystal grain size of the second phase particles in the aluminum alloy foil layer can be set to the above values.

  The aluminum alloy foil layer 3 is preferably subjected to chemical conversion treatment on at least one surface, preferably both surfaces, for the purpose of stabilizing adhesion, preventing dissolution and corrosion, and the like. Here, the chemical conversion treatment refers to a treatment for forming an acid-resistant film on the surface of the aluminum alloy foil layer. That is, it is preferable that the aluminum alloy foil layer 3 has an acid-resistant film on at least one surface thereof. Examples of chemical conversion treatment for forming an acid-resistant film include chromium such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromic acetyl acetate, chromium chloride, and potassium sulfate chromium. Chromate chromate treatment using acid compounds; phosphate chromate treatment using phosphate compounds such as sodium phosphate, potassium phosphate, ammonium phosphate, polyphosphoric acid; represented by the following general formulas (1) to (4) And chromate treatment using an aminated phenol polymer having a repeating unit. In the aminated phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be included singly or in any combination of two or more. Also good.

In general formulas (1) to (4), X represents a hydrogen atom, a hydroxyl group, an alkyl group, a hydroxyalkyl group, an allyl group or a benzyl group. R ¹ and R ² are the same or different and each represents a hydroxyl group, an alkyl group, or a hydroxyalkyl group. In the general formulas (1) to (4), examples of the alkyl group represented by X, R ¹ and R ² include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, C1-C4 linear or branched alkyl groups, such as a tert- butyl group, are mentioned. Examples of the hydroxyalkyl group represented by X, R ¹ and R ² include a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group, 3- C1-C4 straight or branched chain in which one hydroxy group such as hydroxypropyl group, 1-hydroxybutyl group, 2-hydroxybutyl group, 3-hydroxybutyl group, 4-hydroxybutyl group is substituted An alkyl group is mentioned. In the general formulas (1) to (4), the alkyl group and hydroxyalkyl group represented by X, R ¹ and R ² may be the same or different. In the general formulas (1) to (4), X is preferably a hydrogen atom, a hydroxyl group or a hydroxyalkyl group. The number average molecular weight of the aminated phenol polymer having the repeating units represented by the general formulas (1) to (4) is preferably, for example, 500 to 1,000,000, more preferably about 1,000 to 20,000. preferable.

  In addition, as a chemical conversion treatment method for imparting corrosion resistance to the aluminum alloy foil layer 3, a coating in which fine particles of metal oxide such as aluminum oxide, titanium oxide, cerium oxide, tin oxide, or barium sulfate are dispersed in phosphoric acid is coated. And the method of forming a corrosion-resistant process layer in the surface of the aluminum alloy foil layer 3 by baking at 150 degreeC or more is mentioned. Further, a resin layer obtained by crosslinking a cationic polymer with a crosslinking agent may be further formed on the corrosion-resistant treatment layer. Here, examples of the cationic polymer include polyethyleneimine, an ionic polymer complex composed of a polymer having polyethyleneimine and a carboxylic acid, a primary amine graft acrylic resin obtained by graft polymerization of a primary amine on an acrylic main skeleton, and polyallylamine. Or the derivative, aminophenol, etc. are mentioned. As these cationic polymers, only one type may be used, or two or more types may be used in combination. Examples of the crosslinking agent include a compound having at least one functional group selected from the group consisting of an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group, and a silane coupling agent. As these crosslinking agents, only one type may be used, or two or more types may be used in combination.

In addition, as a method for specifically providing an acid-resistant film, for example, as an example, at least the surface on the inner layer side of the aluminum alloy foil is firstly immersed in an alkali soaking method, electrolytic cleaning method, acid cleaning method, electrolytic acid cleaning method. , Degreasing treatment is performed by a known treatment method such as an acid activation method, and then a Cr (chromium) phosphate, Ti (titanium) phosphate, Zr (zirconium) phosphate, Zn phosphate ( Zinc) Treatment liquid (aqueous solution) mainly composed of metal phosphates such as salts and mixtures of these metal salts, or treatment mainly composed of non-metal phosphates and mixtures of these non-metal salts A liquid (aqueous solution) or a treatment liquid (aqueous solution) composed of a mixture of these with an aqueous synthetic resin such as an acrylic resin, a phenolic resin, or a urethane resin, a roll coating method, a gravure printing method, an immersion method, etc. By coating in a known coating method, it is possible to form the acid-resistant coating. For example, when treated with a Cr (chromium) phosphate-based treatment solution, CrPO ₄ (chromium phosphate), AlPO ₄ (aluminum phosphate), Al ₂ O ₃ (aluminum oxide), Al (OH) _x (water Zn ₂ PO ₄ · 4H ₂ O (zinc phosphate hydrate) when treated with an acid-resistant film made of aluminum oxide), AlF _x (aluminum fluoride), etc. ), AlPO ₄ (aluminum phosphate), Al ₂ O ₃ (aluminum oxide), Al (OH) _x (aluminum hydroxide), AlF _x (aluminum fluoride), and the like.

  In addition, as another example of a specific method for providing an acid-resistant film, for example, at least the surface on the inner layer side of the aluminum alloy foil is first subjected to an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, an acid An acid-resistant film can be formed by performing a degreasing process by a known processing method such as an activation method and then performing a known anodizing process on the degreasing surface.

  Other examples of acid-resistant films include phosphate-based and chromic acid-based films. Examples of the phosphate system include zinc phosphate, iron phosphate, manganese phosphate, calcium phosphate, and chromium phosphate. Examples of the chromic acid system include chromium chromate.

  In addition, as another example of the acid-resistant film, by forming an acid-resistant film such as phosphate, chromate, fluoride, triazine thiol compound, between the aluminum and the base material layer at the time of embossing molding Prevention of delamination, hydrogen fluoride generated by the reaction between electrolyte and moisture prevents dissolution and corrosion of the aluminum surface, especially the dissolution and corrosion of aluminum oxide present on the aluminum surface, and adhesion of the aluminum surface This improves the wettability and prevents delamination between the base material layer and aluminum at the time of heat sealing. In the embossed type, it shows the effect of preventing delamination between the base material layer and aluminum at the time of press molding. Among substances that form an acid-resistant film, an aqueous solution composed of three components of a phenol resin, a chromium fluoride (3) compound, and phosphoric acid is applied to the aluminum surface, and the dry baking treatment is good.

  The acid-resistant film includes a layer having cerium oxide, phosphoric acid or phosphate, an anionic polymer, and a crosslinking agent that crosslinks the anionic polymer, and the phosphoric acid or phosphate is 1-100 mass parts may be mix | blended with respect to 100 mass parts of cerium oxides. It is preferable that the acid-resistant film has a multilayer structure further including a layer having a cationic polymer and a crosslinking agent for crosslinking the cationic polymer.

  Furthermore, it is preferable that the anionic polymer is poly (meth) acrylic acid or a salt thereof, or a copolymer having (meth) acrylic acid or a salt thereof as a main component. Moreover, it is preferable that the said crosslinking agent is at least 1 sort (s) chosen from the group which has a functional group in any one of an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group, and a silane coupling agent.

  The phosphoric acid or phosphate is preferably condensed phosphoric acid or condensed phosphate.

  As the chemical conversion treatment, only one type of chemical conversion treatment may be performed, or two or more types of chemical conversion treatment may be performed in combination. Furthermore, these chemical conversion treatments may be carried out using one kind of compound alone, or may be carried out using a combination of two or more kinds of compounds. Among the chemical conversion treatments, chromic acid chromate treatment, chromate treatment combining a chromic acid compound, a phosphoric acid compound, and an aminated phenol polymer are preferable.

  Specific examples of the acid resistant film include those containing at least one of phosphate, chromate, fluoride, and triazine thiol. An acid resistant film containing a cerium compound is also preferable. As the cerium compound, cerium oxide is preferable.

  Specific examples of the acid-resistant film include a phosphate film, a chromate film, a fluoride film, and a triazine thiol compound film. As an acid-resistant film, one of these may be used, or a plurality of combinations may be used. Furthermore, as an acid-resistant film, after degreasing the chemical conversion surface of the aluminum alloy foil, a treatment liquid comprising a mixture of a metal phosphate and an aqueous synthetic resin, or a mixture of a non-metal phosphate and an aqueous synthetic resin It may be formed of a treatment liquid consisting of

The composition of the acid resistant film can be analyzed using, for example, time-of-flight secondary ion mass spectrometry. By analyzing the composition of the acid-resistant film using time-of-flight secondary ion mass spectrometry, for example, at least one secondary ion composed of Ce, P and O (for example, Ce ₂ PO ₄ ⁺ , CePO ₄ ^−, etc.) ) Or a peak derived from a secondary ion composed of Cr, P, and O (for example, at least one kind of CrPO ₂ ⁺ , CrPO ₄ ^−, etc.) is detected.

The amount of the acid-resistant film formed on the surface of the aluminum alloy foil layer 3 in the chemical conversion treatment is not particularly limited. For example, if the above chromate treatment is performed, per 1 m ² of the surface of the aluminum alloy foil layer 3, The chromic acid compound is about 0.5 to about 50 mg, preferably about 1.0 to about 40 mg in terms of chromium, the phosphorus compound is about 0.5 to about 50 mg, preferably about 1.0 to about 40 mg, in terms of phosphorus, and It is desirable that the aminated phenol polymer is contained in an amount of about 1 to about 200 mg, preferably about 5.0 to 150 mg.

  The thickness of the acid-resistant film is not particularly limited, but is preferably about 1 nm to 20 μm, more preferably about 1 to 100 nm, from the viewpoint of the cohesive strength of the film and the adhesive strength with the aluminum alloy foil and the heat-sealing resin layer. More preferably, about 1-50 nm is mentioned. The thickness of the acid-resistant film can be measured by observation with a transmission electron microscope, or a combination of observation with a transmission electron microscope and energy dispersive X-ray spectroscopy or electron energy loss spectroscopy.

  The chemical conversion treatment is performed by applying a solution containing a compound used for forming an acid-resistant film to the surface of the aluminum alloy foil layer by a bar coating method, a roll coating method, a gravure coating method, a dipping method, etc. It is performed by heating so that the temperature of this is about 70 to 200 ° C. Further, before the chemical conversion treatment is performed on the aluminum alloy foil layer, the aluminum alloy foil layer may be previously subjected to a degreasing treatment by an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, or the like. By performing the degreasing treatment in this way, it is possible to more efficiently perform the chemical conversion treatment on the surface of the aluminum alloy foil layer.

[Heat-fusion resin layer 4]
In the battery packaging material of the present invention, the heat-fusible resin layer 4 is a layer provided as necessary and corresponds to the innermost layer. When the battery packaging material of the present invention includes a heat-fusible resin layer, the heat-fusible resin layers are heat-sealed to seal the battery element when the battery is assembled.

  The resin component used in the heat-fusible resin layer 4 is not particularly limited as long as it can be heat-sealed, and examples thereof include polyolefins, cyclic polyolefins, carboxylic acid-modified polyolefins, and carboxylic acid-modified cyclic polyolefins. It is done.

  Specific examples of the polyolefin include polyethylene such as low density polyethylene, medium density polyethylene, high density polyethylene, and linear low density polyethylene; homopolypropylene, polypropylene block copolymer (for example, block copolymer of propylene and ethylene), polypropylene And a random copolymer (for example, a random copolymer of propylene and ethylene); an ethylene-butene-propylene terpolymer; 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 that is a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, and isoprene. Is mentioned. Examples of the cyclic monomer that is a constituent monomer of the cyclic polyolefin include cyclic alkenes such as norbornene; specifically, cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, and norbornadiene. Among these polyolefins, cyclic alkene is preferable, and norbornene is more preferable.

  The carboxylic acid-modified polyolefin is a polymer obtained by modifying the polyolefin by block polymerization or graft polymerization with 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 is obtained by copolymerizing a part of the monomer constituting the cyclic polyolefin in place of the 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 an unsaturated carboxylic acid or its anhydride. The cyclic polyolefin to be modified with carboxylic acid is the same as described above. Moreover, as carboxylic acid used for modification | denaturation, it is the same as that of the said carboxylic acid.

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

  The heat-fusible resin layer 4 may be formed of one kind of resin component alone or may be formed of a blend polymer in which two or more kinds of resin components are combined. Furthermore, the heat-fusible resin layer 4 may be formed of only one layer, but may be formed of two or more layers using the same or different resin components.

  Further, the thickness of the heat-fusible resin layer 4 is not particularly limited as long as it exhibits a function as a heat-fusible resin layer, but is preferably 60 μm or less, more preferably about 15 to 40 μm.

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

  The adhesive layer 5 is formed of an adhesive that can adhere the aluminum alloy foil layer 3 and the heat-fusible resin layer 4. With respect to the adhesive used for forming the adhesive layer 5, the adhesive mechanism, the types of adhesive components, and the like are the same as those of the adhesive layer 2. The adhesive component used for the adhesive layer 5 is preferably a polyolefin resin, more preferably a carboxylic acid-modified polyolefin, particularly preferably a carboxylic acid-modified polypropylene.

  The thickness of the adhesive layer 5 is not particularly limited as long as the battery packaging material satisfies the above physical properties while exhibiting the function as the adhesive layer. For example, the thickness is about 2 to 50 μm, preferably about 10 to 40 μm. .

[Surface coating layer]
In the battery packaging material of the present invention, for the purpose of improving design properties, electrolytic solution resistance, scratch resistance, moldability, and the like, the base material layer 1 is optionally formed (the aluminum alloy of the base material layer 1). If necessary, a surface coating layer (not shown) may be provided on the side opposite to the foil layer 3. A surface coating layer is a layer located in the outermost layer when a 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. Of these, the surface coating layer is preferably formed of a two-component curable resin. Examples of the two-component curable resin that forms the surface coating layer include a two-component curable urethane resin, a two-component curable polyester resin, and a two-component curable epoxy resin. Moreover, you may mix | blend a matting agent with a surface coating layer.

  Examples of the matting agent include fine particles having a particle size of about 0.5 nm to 5 μm. The material of the matting agent is not particularly limited, and examples thereof include metals, metal oxides, inorganic substances, and organic substances. The shape of the matting agent is not particularly limited, and examples thereof include a spherical shape, a fiber shape, a plate shape, an indeterminate shape, and a balloon shape. Specific examples of the matting agent include talc, silica, graphite, kaolin, montmorilloid, montmorillonite, synthetic mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, and aluminum oxide. , Neodymium 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 melting point nylon, crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, nickel and the like can be mentioned. These matting agents may be used individually by 1 type, and may be used in combination of 2 or more type. Among these matting agents, silica, barium sulfate, and titanium oxide are preferable from the viewpoint of dispersion stability and cost. The matting agent may be subjected to various surface treatments such as insulation treatment and 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 matting agent is blended, the matting agent may be added to the two-component curable resin, mixed, and then applied.

  The thickness of the surface coating layer is not particularly limited as long as the battery packaging material satisfies the above physical properties while exhibiting the above function as the surface coating layer. For example, about 0.5 to 10 μm, preferably 1 to For example, about 5 μm.

3. Production method of battery packaging material The production method of the battery packaging material of the present invention is not particularly limited as long as a laminate in which layers of a predetermined composition are laminated is obtained, and at least a base material layer and an aluminum alloy foil And a step of obtaining a laminated body by laminating the layers and the heat-fusible resin layer in this order, and the aluminum alloy foil layer 3 is an optical microscope in a cross section in the thickness direction of the aluminum alloy foil layer. For any 100 second phase particles in the field of view, a linear distance connecting the leftmost end in the vertical direction with respect to the thickness direction and the rightmost end in the vertical direction with respect to the thickness direction of each second phase particle In this case, it is possible to adopt a manufacturing method using a method in which the average of the diameters y of the top 20 second phase particles is 5.0 μm or less in the descending order of the diameter y.
That is, as the aluminum alloy foil layer 3, by using the aluminum alloy foil layer 3 described in the section of “2. Each layer forming the battery packaging material”, by laminating each layer, the battery packaging material of the present invention is obtained. Can be manufactured.

  An example of the method for producing the battery packaging material of the present invention is as follows. First, a laminate in which the base material layer 1, the adhesive layer 2, and the aluminum alloy foil layer 3 are laminated in this order (hereinafter also referred to as “laminate A”) is formed. Specifically, the laminate A is formed by gravure coating an adhesive used for forming the adhesive layer 2 on the base material layer 1 or on the aluminum alloy foil layer 3 whose surface is subjected to chemical conversion treatment as necessary. After applying and drying by a coating method such as a method or a roll coating method, the aluminum alloy foil layer 3 or the base material layer 1 can be laminated and the adhesive layer 2 can be cured by a dry laminating method.

  Next, the heat-fusible resin layer 4 is laminated on the aluminum alloy foil layer 3 of the laminate A. When the heat-fusible resin layer 4 is directly laminated on the aluminum alloy foil layer 3, the resin component constituting the heat-fusible resin layer 4 is applied to the aluminum alloy foil layer 3 of the laminate A by a gravure coating method. It may be applied by a method such as roll coating. In the case where the adhesive layer 5 is provided between the aluminum alloy foil layer 3 and the heat-fusible resin layer 4, for example, (1) the adhesive layer 5 and the heat-melting layer on the aluminum alloy foil layer 3 of the laminate A Method of laminating adhesive resin layer 4 by coextrusion (coextrusion laminating method), (2) Separately, a laminated body in which adhesive layer 5 and heat-fusible resin layer 4 are laminated is formed, and this laminated body A method of laminating on the aluminum alloy foil layer 3 of A by a thermal laminating method, (3) A high temperature in which an adhesive for forming the adhesive layer 5 is extruded or solution-coated on the aluminum alloy foil layer 3 of the laminate A And a method of laminating the heat-fusible resin layer 4 previously formed into a sheet on the adhesive layer 5 by a thermal laminating method, and (4) an aluminum alloy foil of the laminate A Layer 3 and formed into a sheet in advance A method (sandwich laminating method) in which the laminate A and the heat-fusible resin layer 4 are bonded through the adhesive layer 5 while pouring the molten adhesive layer 5 between the heat-fusible resin layer 4 and the like. Can be mentioned.

  When providing a surface coating layer, a surface coating layer is laminated | stacked on the surface on the opposite side to the aluminum alloy foil layer 3 of the base material layer 1. FIG. The surface coating layer can be formed, for example, by applying the above-described resin for forming the surface coating layer to the surface of the base material layer 1. The order of the step of laminating the aluminum alloy 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 are not particularly limited. For example, after forming the surface coating layer on the surface of the base material layer 1, the aluminum alloy foil layer 3 may be formed on the surface of the base material layer 1 opposite to the surface coating layer.

  Surface coating layer / base material layer 1 / adhesive layer 2 provided as necessary / aluminum alloy foil layer 3 whose surface is subjected to chemical conversion treatment as required / as required In order to strengthen the adhesiveness of the adhesive layer 2 and the adhesive layer 5 provided as necessary, a laminate composed of the adhesive layer 5 / the heat-fusible resin layer 4 provided accordingly is formed. You may use for heat processing of a hot roll contact type, a hot air type, a near or far-infrared type. Examples of such heat treatment conditions include 150 to 250 ° C. for 1 to 5 minutes.

  In the battery packaging material of the present invention, each layer constituting the laminate improves or stabilizes film forming properties, lamination processing, suitability for final processing (pouching, embossing), etc., as necessary. Therefore, surface activation treatment such as corona treatment, blast treatment, oxidation treatment, ozone treatment may be performed.

4). Application of Battery Packaging Material The battery packaging material of the present invention is used as a packaging material for sealing and housing battery elements such as a positive electrode, a negative electrode, and an electrolyte.

  Specifically, a battery element including at least a positive electrode, a negative electrode, and an electrolyte is formed using the battery packaging material of the present invention, with the metal terminals connected to each of the positive electrode and the negative electrode protruding outward. By covering the periphery of the element so that a flange portion (region where the heat-fusible resin layers are in contact with each other) can be formed, and heat-sealing the heat-fusible resin layers of the flange portion to seal the battery A battery using the packaging material is provided. In addition, when accommodating a battery element using the battery packaging material of the present invention, the battery packaging material of the present invention is used so that the heat-fusible resin layer is on the inner side (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 secondary battery to which the battery packaging material of the present invention is applied is not particularly limited. For example, a lithium ion battery, a lithium ion polymer battery, a lead battery, a nickel / hydrogen battery, a nickel / cadmium battery , Nickel / iron livestock batteries, nickel / zinc livestock batteries, silver oxide / zinc livestock batteries, metal-air batteries, polyvalent cation batteries, capacitors, capacitors and the like. Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are suitable applications for 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.

(Example 1-24 and Comparative Example 1-14)
<Manufacture of battery packaging materials>
On the base material layer, aluminum alloy foils (thicknesses shown in Tables 1 and 2 respectively) subjected to chemical conversion treatment on both surfaces were laminated by a dry laminating method. Specifically, a two-component urethane adhesive (a polyol compound and an aromatic isocyanate compound) is applied to one surface of an aluminum alloy foil having a second phase particle size and an average crystal particle size described in Table 2. An adhesive layer was formed on the aluminum alloy foil layer. Next, after laminating the adhesive layer and the base material layer on the aluminum alloy foil layer by a dry laminating method, the base material layer / adhesive layer / aluminum alloy foil layer is subjected to aging treatment at 40 ° C. for 24 hours. A laminate was prepared. In addition, the chemical conversion treatment of the aluminum foil is carried out by using a roll coating method to treat the aluminum foil with a treatment solution comprising a phenol resin, a chromium fluoride compound, and phosphoric acid so that the coating amount of chromium is 10 mg / m ² (dry weight). The coating was performed on both surfaces and baked for 20 seconds under the condition that the film temperature was 180 ° C. or higher. Next, on the aluminum alloy foil layer of the laminate, a carboxylic acid-modified polypropylene (arranged on the aluminum alloy foil layer side) and random polypropylene (innermost layer side) are coextruded to form an adhesive layer on the aluminum alloy foil layer. The heat-fusible resin layer was laminated to obtain a battery packaging material in which the base material layer / adhesive layer / aluminum alloy foil layer / adhesive layer / heat-fusible resin layer were laminated in this order. The thickness of each layer is as shown in Table 1. In Tables 1 and 2, PET means polyethylene terephthalate, DL means adhesive layer, ONy means stretched nylon, PPa means carboxylic acid-modified polypropylene, and PP means random polypropylene. Moreover, PET, DL, and ONy in the base material layer are laminated in this order, and ONy is located on the aluminum alloy layer side. Specific materials for the aluminum alloy foil are as follows.

<Aluminum alloy foil>
A8021 material: soft aluminum (JIS H4160 A8021H-O)
The second phase particles and average crystal grain size of the aluminum alloy are adjusted by changing rolling conditions and the like. That is, about the aluminum alloy manufactured by changing various rolling conditions etc., after measuring a 2nd phase particle and an average crystal grain size, it used for manufacture of the packaging material for batteries in an Example and a comparative example.

<Measurement of second phase particle diameter of aluminum alloy foil>
The second-phase particle diameter of the aluminum alloy foil used as the aluminum alloy foil layer of the example and the comparative example is individual among the 100 second-phase particles in the field of view of the optical microscope in the cross section in the thickness direction. The straight line distance connecting the leftmost end in the vertical direction with the thickness direction of the second phase particles and the rightmost end in the vertical direction with the thickness direction is the maximum diameter y, and the average of the top 20 diameters y in descending order of the maximum diameter y Obtained as a value. The results are shown in Table 2.

<Measurement of average grain size of aluminum alloy foil>
The average crystal grain size in the aluminum alloy foil used as the aluminum alloy foil layer in Examples and Comparative Examples was observed by observing a cross section in the thickness direction of the aluminum alloy foil layer with a scanning electron microscope, and arbitrary 100 particles located in the field of view. With respect to the crystal grains of the aluminum alloy, the maximum distance x is defined as a linear distance connecting the leftmost end in the vertical direction with respect to the thickness direction of each crystal grain and the rightmost end in the vertical direction with respect to the thickness direction. The average value of the maximum diameter x was used. The results are shown in Table 2.

(Evaluation of formability)
Each battery packaging material obtained above was cut into a rectangle of 80 mm × 120 mm to prepare a sample. This sample was molded from a molding depth of 0.5 mm with a pressing pressure of 0.4 MPa using a molding die (female die) having a diameter of 30 mm × 50 mm and a corresponding molding die (male die). Cold forming was performed on each of 10 samples at different forming depths in units of 5 mm. For the samples after cold forming, the deepest forming depth at which pinholes and cracks did not occur in all 10 samples in the battery packaging material 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. In addition, since the limit forming depth tends to increase as the thickness of the aluminum alloy foil increases, the standard for formability evaluation is set for each thickness of the aluminum alloy foil. The results are shown in Table 2.

[Evaluation criteria 1: When the thickness of the aluminum alloy foil is 100 μm]
A1: Limit forming depth 20.0 mm or more B1: Limit forming depth 19.0 mm, 19.5 mm
C1: Limit forming depth 18.0mm, 18.5mm
D1: Limit forming depth 17.5mm or less

[Evaluation criteria 2: When the thickness of the aluminum alloy foil is 80 μm]
A2: Limit forming depth 17.0 mm or more B2: Limit forming depth 16.0 mm, 16.5 mm
C2: Limit forming depth 15.0mm, 15.5mm
D2: Limit forming depth 14.5mm or less

[Evaluation criteria 3: When the thickness of the aluminum alloy foil is 50 μm]
A3: Limit forming depth 10.0 mm or more B3: Limit forming depth 9.0 mm, 9.5 mm
C3: Limit forming depth 8.0 mm, 8.5 mm
D3: Limit forming depth 7.5mm or less

[Evaluation criteria 4: When the thickness of the aluminum alloy foil is 40 μm]
A4: Limit forming depth 9.0 mm or more B4: Limit forming depth 8.0 mm, 8.5 mm
C4: Limit forming depth 7.0 mm, 7.5 mm
D4: Limit forming depth 6.5mm or less

[Evaluation criteria 5: When the thickness of the aluminum alloy foil is 35 μm]
A5: Limit forming depth 8.0 mm or more B5: Limit forming depth 7.0 mm, 7.5 mm
C5: Limit forming depth 6.0 mm, 6.5 mm
D5: Limit molding depth 5.5mm or less

[Evaluation Criteria 6: When the thickness of the aluminum alloy foil is 30 μm]
A6: Limit forming depth 7.0 mm or more B6: Limit forming depth 6.0 mm, 6.5 mm
C6: Limit molding depth 5.0 mm, 5.5 mm
D6: Limit forming depth 4.5mm or less

[Evaluation criteria 7: When the thickness of the aluminum alloy foil is 25 μm]
A7: Limit forming depth 6.5 mm or more B7: Limit forming depth 5.5 mm, 6.0 mm
C7: Limit forming depth 4.5mm, 5.0mm
D7: Limit forming depth 4.0 mm or less

[Evaluation criteria 8: When the thickness of the aluminum alloy foil is 20 μm]
A8: Limit forming depth 6.0 mm or more B8: Limit forming depth 5.0 mm, 5.5 mm
C8: Limit forming depth 4.0 mm, 4.5 mm
D8: Limit molding depth 3.5mm or less

[Evaluation Criteria 9: When the thickness of the aluminum alloy foil is 15 μm]
A9: Limit forming depth 5.5 mm or more B9: Limit forming depth 4.5 mm, 5.0 mm
C9: Limit forming depth 3.5mm, 4.0mm
D9: Limit molding depth 3.0mm or less

  As is apparent from the results shown in Table 2, the battery packaging material in which the second phase particle diameter of the aluminum alloy foil is 5 μm or less was excellent in moldability. Furthermore, the battery packaging material in which the second phase particle diameter of the aluminum alloy foil is 5 μm or less and the average crystal particle diameter is 10 μm or less was particularly excellent in moldability. On the other hand, the battery packaging material in which the second phase particle diameter of the aluminum alloy foil exceeds 5 μm was inferior in formability.

DESCRIPTION OF SYMBOLS 1 Base material layer 2 Adhesive layer 3 Aluminum alloy foil layer 4 Heat-fusible resin layer 5 Adhesive layer 31 Crystal grain 32 Second phase particle

Claims (11)

At least a battery packaging material provided with an aluminum alloy foil layer,
In the cross section in the thickness direction of the aluminum alloy foil layer, for any 100 second phase particles in the field of view of the optical microscope, the leftmost end in the direction perpendicular to the thickness direction of the individual second phase particles, Is a battery for which the average of the diameter y of the top 20 second phase particles is 5.0 μm or less when the diameter y is the linear distance connecting the rightmost end in the vertical direction. Packaging material.   In the cross section in the thickness direction of the aluminum alloy foil layer, for any 100 aluminum alloy crystal grains located within the field of view of the scanning electron microscope, the leftmost end in the direction perpendicular to the thickness direction of the individual crystal grains, The average crystal grain size, which is an average value of the maximum diameter x of the 100 crystal grains, is 10.0 μm or less, where the maximum diameter x is a linear distance connecting the thickness direction and the rightmost end in the vertical direction. The battery packaging material according to claim 1, wherein   The aluminum alloy which comprises the said aluminum alloy foil layer contains 0.7 mass% or more and 2.5 mass% or less of Fe, 0.05 mass% or less of Cu, and 0.30 mass% or less of Si. Or the packaging material for batteries of 2.   The battery packaging material according to any one of claims 1 to 3, wherein the aluminum alloy foil layer has an acid-resistant film on at least one surface thereof.   The battery packaging material according to any one of claims 1 to 4, which is a packaging material for a secondary battery.   The battery in which the battery element provided with the positive electrode, the negative electrode, and the electrolyte at least is accommodated in the container formed with the packaging material for batteries in any one of Claims 1-5. At least a base material layer, an aluminum alloy foil layer, and a heat-fusible resin layer are provided so as to be laminated in this order to obtain a laminate.
As the aluminum alloy foil layer, in the cross section in the thickness direction of the aluminum alloy foil layer, any 100 second phase particles in the field of view of the optical microscope are perpendicular to the thickness direction of the individual second phase particles. When the linear distance connecting the leftmost end and the rightmost end in the direction perpendicular to the thickness direction is defined as the diameter y, the average of the diameters y of the top 20 second phase particles in the descending order of the diameter y is 5. The manufacturing method of the packaging material for batteries using what is 0 micrometer or less. An aluminum alloy foil for use in battery packaging materials,
In the cross section in the thickness direction of the aluminum alloy foil, with respect to any 100 second phase particles in the field of view of the optical microscope, the leftmost end in the direction perpendicular to the thickness direction of the individual second phase particles and the thickness direction are A battery packaging in which the average of the diameters y of the top 20 second phase particles in the descending order of the diameter y is 5.0 μm or less, where the linear distance connecting the rightmost end in the vertical direction is the diameter y. Aluminum alloy foil for use in materials.   In the cross section in the thickness direction of the aluminum alloy foil, with respect to any 100 aluminum alloy crystal grains located within the field of view of the scanning electron microscope, the leftmost end in the direction perpendicular to the thickness direction of the individual crystal grains, and When the straight line distance connecting the rightmost end in the vertical direction with the thickness direction is the maximum diameter x, the average crystal grain size, which is an average value of the maximum diameter x of the 100 crystal grains, is 10.0 μm or less. An aluminum alloy foil for use in the battery packaging material according to claim 8.   The aluminum alloy which comprises the said aluminum alloy foil contains 0.7 mass% or more and 2.5 mass% or less of Fe, 0.05 mass% or less of Cu, and 0.30 mass% or less of Si. 9. An aluminum alloy foil for use in the battery packaging material according to 9.   The aluminum alloy foil for use in a battery packaging material according to any one of claims 8 to 10, wherein the aluminum alloy foil has an acid-resistant film on at least one surface thereof.