JP7167930B2 - Battery packaging materials and batteries - Google Patents

Description

TECHNICAL FIELD The present invention relates to a battery packaging material and a battery.

Conventionally, various types of batteries have been developed, and in all batteries, packaging materials have become indispensable members for sealing battery elements such as electrodes and electrolytes. Conventionally, metal packaging materials have been widely used as packaging materials for batteries.

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

Therefore, in recent years, a film-like laminate in which a substrate, a barrier layer, and a heat-sealable resin layer are sequentially laminated has been developed as a packaging material for batteries that can be easily processed into various shapes and can be made thinner and lighter. has been proposed (see Patent Document 1, for example).

In such a battery packaging material, generally, recesses are formed by molding, and battery elements such as electrodes and electrolytic solution are arranged in the spaces formed by the recesses. By fusing, a battery in which the battery element is accommodated inside the battery packaging material is obtained.

JP 2008-287971 A

Vehicles and mobile devices are subject to strong impacts during transportation and use of products, and the batteries used in these products are also subject to strong impacts. If the battery is subjected to a strong impact and the battery packaging material is damaged, there is a risk that the electrolyte or the like may leak out, so the battery packaging material is required to have high impact resistance.

On the other hand, in recent years, there has been a demand for batteries to have a higher capacity and a thinner thickness. However, when the thickness of the battery packaging material is reduced, there is a problem that the impact resistance is lowered.

Further, in the manufacturing process of the battery, when the electrolytic solution is accommodated in the package formed by the battery packaging material, the electrolytic solution adheres to the outer surface of the battery packaging material, discoloring the surface and causing the product to deteriorate. It may become defective.

As described above, there are the above-mentioned problems caused by the battery packaging material, the manufacturing process of the battery, and the mode of use of the battery, and a method capable of solving all these problems is desired.

Under such circumstances, the main object of the present invention is to provide a battery packaging material having high impact resistance and electrolyte resistance. Another object of the present invention is to provide a battery using the battery packaging material.

The inventor of the present invention has made intensive studies to solve the above problems. As a result, it is composed of a laminate including at least a substrate layer, a barrier layer, and a heat-fusible resin layer in this order, and the substrate layer comprises, in order from the barrier layer side, at least a polyamide resin layer and an adhesive resin. and a polyester resin layer, the thickness of the polyester resin layer is 6 μm or less, and the impact strength (J) measured from the base layer side of the laminate in accordance with the provisions of ASTM D3420 is It was found that a battery packaging material having a value obtained by dividing by the thickness (μm) of the laminate of 0.015 J/μm or more has high impact resistance and electrolyte resistance. The present invention has been completed through further studies based on these findings.

That is, the present invention provides inventions in the following aspects.
Section 1. Consists of a laminate comprising at least a substrate layer, a barrier layer, and a heat-fusible resin layer in this order,
The base material layer includes at least a polyamide resin layer, an adhesive resin layer, and a polyester resin layer in order from the barrier layer side,
The polyester resin layer has a thickness of 6 μm or less,
The value obtained by dividing the impact strength (J) measured from the base layer side of the laminate by the thickness (μm) of the laminate in accordance with ASTM D3420 is 0.015J. / μm or more, packaging material for batteries.
Section 2. An adhesive layer is provided between the base material layer and the barrier layer,
Item 2. The battery packaging material according to Item 1, wherein each of the adhesive resin layer and the adhesive layer has a hardness of 50 MPa or less as measured by a nanoindentation method.
Item 3. Item 3. The battery according to Item 1 or 2, wherein the adhesive resin layer is made of at least one selected from the group consisting of acid-modified polyolefin resins, acid-modified styrene-based elastomer resins, and acid-modified polyester-based elastomer resins. packaging material for
Section 4. Item 4. The battery packaging material according to any one of Items 1 to 3, wherein the heat-fusible resin layer is made of unstretched polypropylene.
Item 5. Item 5. The battery packaging material according to any one of items 1 to 4, wherein the ratio of the thickness of the polyester resin layer to the thickness of the polyamide resin layer is 0.5 or less.
Item 6. Item 6. The battery packaging material according to any one of Items 1 to 5, wherein the laminate has a thickness of 180 μm or less.
Item 7. Item 7. The battery packaging material according to any one of Items 1 to 6, wherein the polyamide resin layer is made of nylon.
Item 8. Item 8. The battery packaging material according to any one of Items 1 to 7, wherein the polyester resin layer is composed of polyethylene terephthalate.
Item 9. Item 9. A battery, wherein a battery element comprising 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.

According to the present invention, it is possible to provide a battery packaging material having high impact resistance and electrolyte resistance. Furthermore, according to the present invention, it is possible to provide a battery using the battery packaging material.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows an example of the cross-sectional structure of the packaging material for batteries of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows an example of the cross-sectional structure of the packaging material for batteries of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows an example of the cross-sectional structure of the packaging material for batteries of this invention.

The battery packaging material of the present invention is composed of a laminate comprising at least a substrate layer, a barrier layer and a heat-fusible resin layer in this order. The substrate layer includes at least a polyamide resin layer, an adhesive resin layer, and a polyester resin layer in order from the barrier layer side. Moreover, the thickness of the polyester resin layer is 6 μm or less. Furthermore, in accordance with the provisions of ASTM D3420, the value obtained by dividing the impact strength (J) measured from the base layer side of the laminate by the thickness (μm) of the laminate is 0.015 J / μm or more. The battery packaging material of the present invention has such a structure, and thus has high impact resistance and electrolytic solution resistance. The battery packaging material of the present invention will be described in detail below.

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

1. Laminate structure and physical properties of battery packaging material The battery packaging material 10 of the present invention comprises at least a substrate layer 1, a barrier layer 3, and a heat-fusible resin layer 4 in this order, as shown in FIG. consists of the body. The substrate layer 1 includes at least a polyamide resin layer 1a, an adhesive resin layer 1b, and a polyester resin layer 1c in order from the barrier layer 3 side.

In the battery packaging material of the present invention, the polyester resin layer 1c of the substrate layer 1 is the outermost layer, and the heat-fusible resin layer 4 is the innermost layer. That is, when the battery is assembled, the heat-sealable resin layers 4 positioned at the periphery of the battery element are heat-sealed to seal the battery element, thereby sealing the battery element.

As shown in FIGS. 2 and 3, in the battery packaging material 10 of the present invention, an adhesive layer 2 is optionally provided between the base layer 1 and the barrier layer 3 for the purpose of enhancing the adhesion between them. may be provided. Further, as shown in FIG. 3, an adhesive layer 5 may be provided between the barrier layer 3 and the heat-fusible resin layer 4, if necessary, for the purpose of enhancing the adhesiveness therebetween.

In the battery packaging material of the present invention, the impact strength (J) measured from the base layer 1 side of the laminate constituting the battery packaging material is measured in accordance with ASTM D3420. A value P obtained by dividing by the thickness (μm) of is 0.015 J/μm or more. In the battery packaging material of the present invention, the substrate layer 1 includes at least a polyamide resin layer 1a, an adhesive resin layer 1b, and a polyester resin layer 1c in this order from the barrier layer 3 side, and such characteristics Therefore, although the thickness of the polyester resin layer is set to 6 μm or less, high impact resistance and high electrolytic solution resistance can be exhibited. The impact head of the measuring device has a radius of 12.7 mm and a hemispherical tip with a smooth surface. A sample cut to a diameter of 100 mm is used for impact strength measurement. The sample is clamped between two plates with a circular opening of 89±0.5 mm diameter in the center.

From the viewpoint of further improving the impact resistance, the impact strength (J) measured from the base layer 1 side of the laminate constituting the battery packaging material is divided by the thickness (μm) of the laminate. The lower limit of the value P obtained by is preferably about 0.015 J/μm or more, more preferably about 0.016 J/μm or more, and the upper limit is preferably about 0.020 J/μm or less, more preferably about 0.020 J/μm or less. Preferably, it is about 0.019 J/μm or less. Further, the preferable range of the value P is about 0.015 to 0.020 J/μm, about 0.015 to 0.019 J/μm, about 0.016 to 0.020 J/μm, and 0.016 to 0. 019 J/μm or so.

As a method for setting the value P to the above value, the substrate layer 1 includes at least a polyamide resin layer 1a, an adhesive resin layer 1b, and a polyester resin layer 1c in order from the barrier layer 3 side, and Furthermore, after setting the thickness of the polyester resin layer 1c to 6 μm or less, a method of adjusting the material and thickness of each layer, which will be described later, can be adopted.

In addition, in the battery packaging material of the present invention, the impact strength (J) may satisfy the value P in relation to the thickness of the laminate constituting the battery packaging material, but is preferably 1.4 J. above, more preferably 1.6 J or more, and still more preferably 1.7 J or more. The upper limit of the impact strength (J) is, for example, 3.0J and 2.8J.

The thickness of the laminate constituting the battery packaging material 10 of the present invention is not particularly limited. 180 μm or less, preferably about 160 μm or less, more preferably about 60 to 180 μm, still more preferably about 60 to 160 μm, even more preferably about 80 to 160 μm, particularly preferably about 100 to 160 μm.

2. Each layer forming the battery packaging material [base layer 1]
In the battery packaging material 10 of the present invention, the base material layer 1 is the outermost layer. The substrate layer 1 includes, in order from the barrier layer 3 side, at least a polyamide resin layer 1a, an adhesive resin layer 1b, and a polyester resin layer 1c.

The polyamide resin layer 1a is a layer made of polyamide, and by being made of polyamide, it imparts toughness and plays a role of improving the moldability of the battery packaging material 10, and also has flexibility, puncture resistance, Cold resistance can also be imparted. In the present invention, the polyamide resin layer 1a is located on the barrier layer 3 side of the substrate layer 1, and ensures the high impact resistance of the present invention together with the polyester resin layer 1c.

Specific examples of polyamides include aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and copolymers of nylon 6 and nylon 66; derived from terephthalic acid and/or isophthalic acid Hexamethylenediamine-isophthalic acid-terephthalic acid copolymer polyamide such as nylon 6I, nylon 6T, nylon 6IT, nylon 6I6T (I represents isophthalic acid, T represents terephthalic acid), polymetaxylylene adipamide Polyamides containing aromatics such as (MXD6); Alicyclic polyamides such as polyaminomethylcyclohexyladipamide (PACM6); Polyamides obtained by copolymerizing lactam components and isocyanate components such as 4,4'-diphenylmethane-diisocyanate , polyesteramide copolymers and polyetheresteramide copolymers, which are copolymers of copolymerized polyamide and polyester or polyalkylene ether glycol; and copolymers thereof. These polyamides may be used singly or in combination of two or more. The stretched polyamide film has excellent stretchability and can prevent whitening due to cracking of the resin in the substrate layer 1 during molding, and is suitably used as a material for forming the polyamide resin layer 1a.

Among polyamides, the polyamide resin layer 1a is preferably made of nylon.

From the viewpoint of imparting high impact resistance while suppressing an increase in the thickness of the battery packaging material, the thickness of the polyamide resin layer 1a is preferably about 12 to 25 μm, more preferably about 15 to 24 μm. be done.

Moreover, the polyester resin layer 1c is a layer made of polyester. The polyester resin layer 1 c constitutes the outermost layer of the base material layer 1 . That is, the polyester resin layer 1c constitutes the outermost layer of the battery packaging material of the present invention, and exhibits excellent electrolyte resistance. Moreover, as described above, the polyester resin layer 1c assures the high impact resistance of the present invention together with the polyamide resin layer 1a.

Specific examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, copolymer polyester mainly composed of repeating units of ethylene terephthalate, and butylene terephthalate mainly composed of repeating units. and copolymerized polyester. Further, as the copolymer polyester having ethylene terephthalate as the main repeating unit, specifically, a copolymer polyester polymerized with ethylene isophthalate having ethylene terephthalate as the main repeating unit (hereinafter referred to as polyethylene (terephthalate/isophthalate) ), polyethylene (terephthalate/isophthalate), polyethylene (terephthalate/adipate), polyethylene (terephthalate/sodium sulfoisophthalate), polyethylene (terephthalate/sodium isophthalate), polyethylene (terephthalate/phenyl-dicarboxylate) , polyethylene (terephthalate/decanedicarboxylate), and the like. Further, as the copolymer polyester having butylene terephthalate as the main repeating unit, specifically, a copolymer polyester polymerized with butylene isophthalate having butylene terephthalate as the main repeating unit (hereinafter referred to as polybutylene (terephthalate/isophthalate) ), polybutylene (terephthalate/adipate), polybutylene (terephthalate/sebacate), polybutylene (terephthalate/decanedicarboxylate), polybutylene naphthalate, and the like. These polyesters may be used singly or in combination of two or more. Polyester has an advantage that it is excellent in resistance to electrolytic solution and hardly causes whitening or the like due to adhesion of electrolytic solution.

Among polyesters, the polyester resin layer 1c is preferably made of polyethylene terephthalate, and more preferably made of stretched polyethylene terephthalate.

The thickness of the polyester resin layer 1c may be 6 μm or less. The thickness is preferably about 1 to 6 μm, more preferably about 1 to 5 μm.

From the viewpoint of imparting high impact resistance and electrolytic solution resistance while suppressing an increase in the thickness of the battery packaging material, the ratio of the thickness of the polyester resin layer 1c to the thickness of the polyamide resin layer 1a (polyester resin The upper limit of the thickness of layer 1c/thickness of polyamide resin layer 1a) is preferably about 0.5 or less, more preferably about 0.3 or less, and still more preferably about 0.25 or less. is preferably about 0.01 or more, more preferably about 0.03 or more, and still more preferably 0.04 or more. The range of the ratio is preferably about 0.01 to 0.5, about 0.01 to 0.3, about 0.01 to 0.25, about 0.03 to 0.5, 0.03 to about 0.3, about 0.03 to 0.25, about 0.04 to 0.5, about 0.04 to 0.3, and about 0.04 to 0.25.

The adhesive resin layer 1b is a layer made of a resin that bonds the polyamide resin layer 1a and the polyester resin layer 1c. The adhesion 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 heat pressure type, an electron beam curing type, an ultraviolet curing type, and the like.

In the present invention, the hardness of the adhesive resin layer 1b measured by the nanoindentation method is preferably 50 MPa or less. In the battery packaging material of the present invention, the hardness of the adhesive resin layer 1b is 50 MPa or less, and the adhesive layer 2, which is located between the base material layer 1 and the barrier layer 3, is also When the hardness measured by the nanoindentation method is 50 MPa or less, excellent moldability can be exhibited. This mechanism can be considered, for example, as follows. That is, since the hardness of these layers is designed to be smaller than that of ordinary adhesives, even though the base material layer 1 has a polyester resin layer 1c (polyester resins are generally made of nylon or the like), The adhesive resin layer 1b and the adhesive layer 2 suitably suppress the rapid deformation of the barrier layer 3 due to the deformation of the base material layer 1 during molding. As a result, it is considered that the occurrence of cracks and pinholes in the barrier layer 3 is effectively suppressed.

The hardness of the polyester resin layer 1c is preferably about 10 to 50 MPa, more preferably about 15 to 40 MPa, from the viewpoint of enhancing the moldability of the battery packaging material.

In the present invention, the hardnesses of the adhesive resin layer 1b and the adhesive layer 2 measured by the nanoindentation method are values measured as follows. As an apparatus, a nanoindenter ("TriboIndenter TI950" manufactured by HYSITRON) is used.As an indenter for the nanoindenter, a Berkovich indenter (triangular pyramid) is used. , in an environment of 50% relative humidity and 23 ° C., the indenter is applied to the surface of the adhesive layer 2 of the battery packaging material (the surface where the adhesive layer 2 is exposed, perpendicular to the stacking direction of each layer) The indenter is pressed into the adhesive layer over 10 seconds to a load of 40 μN from the surface, held there for 5 seconds, and then unloaded over 10 seconds.Maximum load P _max (μN) and maximum depth Using the contact projected area A (μm ² ) at the time of contact, the indentation hardness (MPa) is calculated from P _max /A.The hardness of the adhesive resin layer 1b is determined with a load of 10 μN. Other than that, it can be measured in the same manner as the adhesive layer 2 .

The adhesive used to form the adhesive resin layer 1b is preferably a resin composition containing a modified thermoplastic resin graft-modified with an unsaturated carboxylic acid or unsaturated carboxylic acid derivative component. Examples of the modified thermoplastic resin include resins obtained by modifying polyolefin resins, styrene elastomers, polyester elastomers, etc. with unsaturated carboxylic acid derivative components. The said resin may be used individually by 1 type, and may be used in combination of 2 or more types. Examples of unsaturated carboxylic acid derivative components include acid anhydrides of unsaturated carboxylic acids and esters of unsaturated carboxylic acids. As the unsaturated carboxylic acid derivative component, one type may be used alone, or two or more types may be used in combination.

Polyolefin resins in modified thermoplastic resins include low-density polyethylene, medium-density polyethylene, high-density polyethylene; ethylene-α-olefin copolymer; homo, block or random polypropylene; propylene-α-olefin copolymer; Copolymers obtained by copolymerizing polar molecules such as acrylic acid and methacrylic acid; and polymers such as crosslinked polyolefins. Polyolefin-based resins may be used alone or in combination of two or more.

Styrene-based elastomers in modified thermoplastic resins include copolymers of styrene (hard segment) and butadiene, isoprene, or hydrogenated products thereof (soft segment). Polyolefin-based resins may be used alone or in combination of two or more.

Examples of polyester-based elastomers in modified thermoplastic resins include copolymers of crystalline polyester (hard segment) and polyalkylene ether glycol (soft segment). Polyolefin-based resins may be used alone or in combination of two or more.

Examples of unsaturated carboxylic acids in modified thermoplastic resins include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, bicyclo[2,2,1]hept-2-ene- 5,6-dicarboxylic acid and the like. Acid anhydrides of unsaturated carboxylic acids include, for example, maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo[2,2,1]hept-2-ene-5,6- and dicarboxylic anhydrides. Examples of unsaturated carboxylic acid esters include methyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dimethyl maleate, monomethyl maleate, diethyl fumarate, dimethyl itaconate, diethyl citraconate, tetrahydro Examples thereof include unsaturated carboxylic acid esters such as dimethyl phthalate anhydride and dimethyl bicyclo[2,2,1]hept-2-ene-5,6-dicarboxylate.

As the modified thermoplastic resin, 0.2 to 100 parts by mass of the unsaturated carboxylic acid derivative component is reacted with 100 parts by mass of the base thermoplastic resin by heating in the presence of a radical initiator. is obtained by

The reaction temperature is preferably 50 to 250°C, more preferably 60 to 200°C. Although the reaction time depends on the production method, in the case of melt graft reaction using a twin-screw extruder, it is preferably 2 to 30 minutes, more preferably 5 to 10 minutes, which is within the residence time of the extruder. Further, the modification reaction can be carried out under either normal pressure or pressurized conditions.

Radical initiators used in the modification reaction include organic peroxides. As the organic peroxide, various materials can be selected depending on the temperature conditions and reaction time. oxyesters, hydroperoxides and the like. In the case of the melt graft reaction by the twin-screw extruder described above, alkyl peroxides, peroxyketals and peroxyesters are preferred, and di-t-butyl peroxide, 2,5-dimethyl-2,5-di-t- More preferably, butylperoxy-hexyne-3, dicumyl peroxide is used.

The hardness of the adhesive resin layer 1b can be adjusted not only by the type of resin contained in the adhesive, but also by adjusting the molecular weight of the resin, the number of cross-linking points, the modification ratio, the stretching ratio, the stretching temperature, and the like. value can be adjusted.

Further, from the viewpoint of further improving the moldability of the battery packaging material, the hardness of the polyester resin layer 1c measured by the nanoindentation method is preferably about 300 to 400 MPa, more preferably about 300 to 350 MPa. . Furthermore, the hardness of the polyamide resin layer 1a measured by the nanoindentation method is preferably about 200 to 400 MPa, more preferably about 200 to 350 MPa.

In the present invention, the hardness of the polyester resin layer 1c and the polyamide resin layer 1a measured by the nanoindentation method is the hardness measurement object in the above-described method of measuring the hardness of the adhesive resin layer 1b. Measurement can be performed in the same manner as for the adhesive resin layer 1b except that the polyester resin layer 1c or the polyamide resin layer 1a is used and the indentation load is 100 μN.

From the viewpoint of imparting high impact resistance while suppressing an increase in the thickness of the battery packaging material, the thickness of the adhesive resin layer 1b is preferably about 0.5 to 2 μm, more preferably 0.8 to 0.8 μm. About 1.2 μm can be mentioned.

The base material layer 1 may further include other layers in addition to the polyamide resin layer 1a, the adhesive resin layer 1b, and the polyester resin layer 1c. Examples of materials constituting other layers include epoxy resins, acrylic resins, fluorine resins, polyurethanes, silicon resins, phenol resins, polyetherimides, polyimides, and mixtures and copolymers thereof. Moreover, each of the polyamide resin layer 1a, the adhesive resin layer 1b, and the polyester resin layer 1c may be a single layer or a multilayer.

In the present invention, from the viewpoint of improving the moldability of the battery packaging material, it is preferable that a lubricant is adhered to the surface of the substrate layer 1 side. The lubricant is not particularly limited, but preferably includes an amide-based lubricant. Specific examples of amide-based lubricants include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylolamides, saturated fatty acid bisamides, and unsaturated fatty acid bisamides. Specific examples of saturated fatty acid amides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide. Specific examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide. Specific examples of substituted amides include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide and the like. Further, specific examples of methylolamide include methylol stearamide. Specific examples of saturated fatty acid bisamides include methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, ethylenebisstearic acid amide, ethylenebishydroxystearic acid amide, ethylenebisbehenic acid amide, hexamethylenebisstearin. acid amide, hexamethylenebisbehenamide, hexamethylenehydroxystearic acid amide, N,N'-distearyladipic acid amide, N,N'-distearylsebacic acid amide and the like. Specific examples of unsaturated fatty acid bisamides include ethylenebisoleic acid amide, ethylenebiserucic acid amide, hexamethylenebisoleic acid amide, N,N'-dioleyladipic acid amide, and N,N'-dioleylsebacic acid amide. etc. Specific examples of fatty acid ester amides include stearamide ethyl stearate. Further, specific examples of the aromatic bisamide include m-xylylenebisstearic acid amide, m-xylylenebishydroxystearic acid amide, N,N'-distearyl isophthalic acid amide and the like. Lubricants may be used singly or in combination of two or more.

When a lubricant exists on the surface of the substrate layer ¹ , the amount of the lubricant is not particularly limited. Up to about 15 mg/m ² , more preferably about 5 to 14 mg/m ² .

The thickness of the base material layer 1 is preferably about 15 μm or more, more preferably 15 μm or more, from the viewpoint of imparting high impact resistance and electrolytic solution resistance while suppressing an increase in the thickness of the battery packaging material. About 30 μm, more preferably about 20 to 30 μm.

[Adhesive layer 2]
In the battery packaging material 10 of the present invention, the adhesive layer 2 is a layer provided between the base material layer 1 and the barrier layer 3 as necessary in order to firmly bond them.

The adhesive layer 2 is made of an adhesive capable of bonding the base material layer 1 and the barrier layer 3 together. The adhesive used to form the adhesive layer 2 may be a two-component curing adhesive or a one-component curing adhesive. Furthermore, the adhesion mechanism of the adhesive used to form the adhesive layer 2 is not particularly limited, and may be any of chemical reaction type, solvent volatilization type, heat melting type, heat pressure type, and the like.

In the present invention, the hardness of the adhesive layer 2 measured by the nanoindentation method is preferably 50 MPa or less. As described above, in the battery packaging material of the present invention, when both the hardness measured by the nanoindentation method of the adhesive resin layer 1b and the adhesive layer 2 are 50 MPa or less, excellent moldability is exhibited. becomes possible. The method for measuring the hardness of the adhesive layer 2 is as described above.

The hardness of the adhesive layer 2 is preferably about 10 to 50 MPa, more preferably about 20 to 40 MPa, from the viewpoint of improving the moldability of the battery packaging material.

The hardness of the adhesive layer 2 is determined not only by the type of resin contained in the adhesive, but also by the molecular weight of the resin, the number of crosslinking points, the ratio of the main agent and the curing agent, the dilution ratio of the main agent and the curing agent, the drying temperature, By adjusting the aging temperature, aging time, etc., the above values can be obtained.

Specific examples of adhesive components that can be used to form the adhesive layer 2 include polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolymerized polyester; Polyurethane adhesive; Epoxy resin; Phenolic resin; Polyamide resin such as nylon 6, nylon 66, nylon 12, copolyamide; Polyolefin such as polyolefin, carboxylic acid-modified polyolefin, metal-modified polyolefin Resins, polyvinyl acetate resins; cellulose adhesives; (meth)acrylic resins; polyimide resins; polycarbonates; amino resins such as urea resins and melamine resins; Examples include silicone-based resins. These adhesive components may be used singly or in combination of two or more. Among these adhesive components, polyurethane-based adhesives are preferred.

The thickness of the adhesive layer 2 is not particularly limited as long as it functions as an adhesive layer.

[Barrier layer 3]
In the battery packaging material of the present invention, the barrier layer 3 is a layer that has the function of improving the strength of the battery packaging material and also preventing water vapor, oxygen, light, and the like from entering the inside of the battery. The barrier layer 3 can be formed of a metal foil, a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, a film provided with these vapor deposition layers, or the like. is preferably Specific examples of the metal forming the barrier layer include aluminum, stainless steel, titanium, and the like, preferably aluminum. From the viewpoint of preventing wrinkles and pinholes in the barrier layer 3 during production of the battery packaging material, the barrier layer is made of, for example, annealed aluminum (JIS H4160: 1994 A8021H-O, JIS H4160: 1994 A8079H-O, JIS H4000:2014 A8021P-O, JIS H4000:2014 A8079P-O).

The thickness of the barrier layer 3 is not particularly limited as long as it functions as a barrier layer against water vapor. be done.

At least one surface, preferably both surfaces, of the barrier layer 3 is preferably subjected to a chemical conversion treatment in order to stabilize adhesion and prevent dissolution and corrosion. Here, chemical conversion treatment refers to treatment for forming an acid-resistant film on the surface of the barrier layer. Examples of chemical conversion treatments include chromate treatment using chromium compounds such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium biphosphate, chromic acid acetyl acetate, chromium chloride, and potassium chromium sulfate; phosphoric acid treatment using a phosphoric acid compound such as sodium phosphate, potassium phosphate, ammonium phosphate, polyphosphoric acid; and chemical conversion treatment. In the aminated phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be contained singly or in any combination of two or more. good too.

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

In addition, as a chemical conversion treatment method for imparting corrosion resistance to the barrier layer 3, fine particles of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide, and barium sulfate are dispersed in phosphoric acid. A method of forming an acid-resistant film on the surface of the barrier layer 3 by performing a baking treatment at 150° C. or higher can be mentioned. A resin layer obtained by cross-linking a cationic polymer with a cross-linking agent may be further formed on the acid-resistant film. Examples of the cationic polymer include polyethyleneimine, an ionic polymer complex composed of a polymer containing polyethyleneimine and carboxylic acid, a primary amine-grafted acrylic resin obtained by graft-polymerizing a primary amine to an acrylic backbone, and polyallylamine. or derivatives thereof, aminophenol and the like. As these cationic polymers, only one type may be used, or two or more types may be used in combination. Examples of cross-linking agents include compounds having at least one functional group selected from the group consisting of isocyanate groups, glycidyl groups, carboxyl groups, and oxazoline groups, and silane coupling agents. As these cross-linking agents, only one type may be used, or two or more types may be used in combination.

As a specific method for providing the acid-resistant film, for example, at least the inner layer side surface of the aluminum foil is first subjected to an alkali immersion method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, Perform degreasing treatment by a well-known treatment method such as an acid activation method, and then apply metal phosphates such as chromium phosphate, titanium phosphate, zirconium phosphate, zinc phosphate, and these metals to the degreased surface. A treatment liquid (aqueous solution) mainly composed of a mixture of salts, or a treatment liquid (aqueous solution) mainly composed of a non-metallic phosphate and a mixture of these non-metallic salts, or these and an acrylic resin or Acid-resistant film is formed by applying a treatment liquid (aqueous solution) consisting of a mixture of water-based synthetic resins such as phenolic resins and urethane resins by well-known coating methods such as roll coating, gravure printing, and dipping. can be formed. For example, when treated with a chromium phosphate-based treatment solution, it becomes an acid-resistant film made of chromium phosphate, aluminum phosphate, aluminum oxide, aluminum hydroxide, aluminum fluoride, etc., and treated with a zinc phosphate-based treatment solution. In this case, an acid-resistant film composed of zinc phosphate hydrate, aluminum phosphate, aluminum oxide, aluminum hydroxide, aluminum fluoride, or the like is formed.

Further, as other specific examples of the method for providing the acid-resistant film, for example, at least the inner layer side surface of the aluminum foil is first subjected to an alkali immersion method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, an acid activated An acid-resistant film can be formed by performing a degreasing treatment by a well-known treatment method such as a degreasing method, and then subjecting the degreased surface to a well-known anodizing treatment.

Other examples of the acid-resistant coating include phosphate-based and chromic acid-based coatings. Phosphate type includes zinc phosphate, iron phosphate, manganese phosphate, calcium phosphate, chromium phosphate and the like, and chromic acid type includes chromium chromate and the like.

Further, as another example of the acid-resistant film, by forming an acid-resistant film of phosphate, chromate, fluoride, triazinethiol compound, or the like, it is possible to improve the adhesion between the aluminum and the base layer during embossing. Prevention of delamination, prevention of dissolution and corrosion of the aluminum surface, especially dissolution and corrosion of aluminum oxide existing on the aluminum surface, and adhesion of the aluminum surface by hydrogen fluoride generated by the reaction between the electrolyte and moisture. It exhibits the effect of improving wettability, preventing delamination between the base material layer and aluminum during heat sealing, and preventing delamination between the base material layer and aluminum during press molding in the case of the embossed type. Among the substances that form an acid-resistant film, an aqueous solution composed of three components, phenolic resin, chromium (III) fluoride compound, and phosphoric acid, is applied to the surface of aluminum, followed by dry baking.

Further, the acid-resistant film includes a layer having cerium oxide, phosphoric acid or a phosphate, an anionic polymer, and a cross-linking agent that cross-links the anionic polymer, and the phosphoric acid or phosphate is the About 1 to 100 parts by mass may be blended with 100 parts by mass of cerium oxide. It is preferable that the acid-resistant film has a multi-layer structure further including a layer having a cationic polymer and a cross-linking agent for cross-linking the cationic polymer.

Further, the anionic polymer is preferably poly(meth)acrylic acid or a salt thereof, or a copolymer containing (meth)acrylic acid or a salt thereof as a main component. Moreover, the cross-linking agent is preferably at least one selected from the group consisting of a compound having a functional group such as an isocyanate group, a glycidyl group, a carboxyl group, or an oxazoline group, and a silane coupling agent.

Further, the phosphoric acid or phosphate is preferably condensed phosphoric acid or condensed phosphate.

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

Specific examples of acid-resistant coatings include those containing at least one of phosphates, chromates, fluorides, and triazinethiols. An acid-resistant film containing a cerium compound is also preferred. As the cerium compound, cerium oxide is preferred.

Further, specific examples of acid-resistant coatings include phosphate-based coatings, chromate-based coatings, fluoride-based coatings, and triazinethiol compound coatings. The acid-resistant coating may be one of these, or may be a combination of multiple types. Furthermore, as the acid-resistant film, after degreasing the chemically treated surface of the aluminum foil, It may be formed of a different treatment liquid.

The composition of the acid-resistant coating can be analyzed using, for example, time-of-flight secondary ion mass spectrometry. By analyzing the composition of the acid-resistant coating using time-of-flight secondary ion mass spectrometry, peaks derived from at least one of Ce ⁺ and Cr ⁺ are detected, for example.

It is preferable that the surface of the aluminum foil is provided with an acid-resistant film containing at least one element selected from the group consisting of phosphorus, chromium and cerium. X-ray photoelectron spectroscopy is used to confirm that at least one element selected from the group consisting of phosphorus, chromium and cerium is contained in the acid-resistant coating on the surface of the aluminum foil of the battery packaging material. be able to. Specifically, first, in the battery packaging material, the heat-fusible resin layer, the adhesive layer, and the like laminated on the aluminum foil are physically peeled off. Next, the aluminum foil is placed in an electric furnace, and organic components present on the surface of the aluminum foil are removed at about 300° C. for about 30 minutes. After that, the inclusion of these elements is confirmed using X-ray photoelectron spectroscopy of the surface of the aluminum foil.

The amount of the acid-resistant film formed on the surface of the barrier layer ³ in the chemical conversion treatment is not particularly limited. About 0.5 to 50 mg, preferably about 1.0 to 40 mg, in terms of phosphorus compound, about 0.5 to 50 mg, preferably about 1.0 to 40 mg in terms of phosphorus, and aminated phenol polymer is 1.0 It is desired to be contained in a ratio of about 200 mg, preferably about 5.0 to 150 mg.

The thickness of the acid-resistant coating is not particularly limited, but is preferably about 1 nm to 10 μm, more preferably 1 to 100 nm, from the viewpoint of the cohesion of the coating and the adhesion to the aluminum foil or the heat-sealable resin layer. about 1 to 50 nm, more preferably about 1 to 50 nm. The thickness of the acid-resistant film can be measured by observation with a transmission electron microscope, or by a combination of observation with a transmission electron microscope and energy dispersive X-ray spectroscopy or electron beam energy loss spectroscopy.

In the chemical conversion treatment, a solution containing a compound used for forming an acid-resistant film is applied to the surface of the barrier layer by a bar coating method, a roll coating method, a gravure coating method, an immersion method, or the like. It is carried out by heating to about 200°C. In addition, before the barrier layer is subjected to the chemical conversion treatment, the barrier layer may be previously subjected to a degreasing treatment by an alkali immersion 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 becomes possible to perform the chemical conversion treatment on the surface of the barrier layer more efficiently.

[Heat-fusible resin layer 4]
In the battery packaging material of the present invention, the heat-fusible resin layer 4 corresponds to the innermost layer, and is a layer that seals the battery element by heat-fusifying the heat-fusible resin layers to each other when the battery is assembled.

The resin component used for the heat-fusible resin layer 4 is not particularly limited as long as it is heat-fusible, and examples thereof include polyolefins, cyclic polyolefins, acid-modified polyolefins, and acid-modified cyclic polyolefins. That is, the resin constituting the heat-fusible resin layer 4 may or may not contain a polyolefin skeleton, and preferably contains a polyolefin skeleton. Whether the resin constituting the heat-fusible 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 maleic anhydride-modified polyolefin is measured by infrared spectroscopy, peaks derived from maleic anhydride are detected near wavenumbers of 1760 cm ⁻¹ and 1780 cm ⁻¹ . However, if the degree of acid denaturation is low, the peak may be too small to be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

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

The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer. Examples of olefins that are constituent monomers of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, butadiene, and isoprene. be done. Examples of cyclic monomers constituting the cyclic polyolefin include cyclic alkenes such as norbornene; specific examples thereof include cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene and norbornadiene. Among these polyolefins, cyclic alkenes are preferred, and norbornene is more preferred.

The acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of the polyolefin with an acid component such as carboxylic acid. Acid components used for modification include, for example, carboxylic acids such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, itaconic anhydride, and anhydrides thereof.

The acid-modified cyclic polyolefin is obtained by copolymerizing a part of the monomers constituting the cyclic polyolefin with α,β-unsaturated carboxylic acid or its anhydride, or by copolymerizing α,β- It is a polymer obtained by block polymerization or graft polymerization of an unsaturated carboxylic acid or its anhydride. The carboxylic acid-modified cyclic polyolefin is the same as described above. The carboxylic acid used for modification is the same as those used for modifying the carboxylic acid-modified polyolefin.

Among these resin components, preferred are polyolefins such as polypropylene and carboxylic acid-modified polyolefins; more preferred are polypropylene and acid-modified polypropylene.

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

From the viewpoint of imparting high impact resistance while suppressing an increase in the thickness of the battery packaging material, the heat-fusible resin layer 4 is preferably made of unstretched polypropylene. From the same point of view, in particular, the adhesive layer 5, which will be described later, is made of a cured polyurethane adhesive having a thickness of about 1 to 5 μm, and the heat-fusible resin layer 4 has a thickness of about 20 to 80 μm. It is preferably made of unstretched polypropylene.

In the present invention, from the viewpoint of improving the moldability of the battery packaging material, it is preferable that the surface of the heat-fusible resin layer 4 is coated with a lubricant. The lubricant is not particularly limited, but preferably includes an amide-based lubricant. Specific examples of amide-based lubricants include those described above.

When a lubricant exists on the surface of the heat-sealable resin layer ⁴ , the amount of the lubricant is not particularly limited. is about 4 to 15 mg/m ² , more preferably about 5 to 14 mg/m ² .

The thickness of the heat-fusible resin layer 4 is not particularly limited as long as it functions as a heat-fusible resin layer. About 15 to 80 μm can be mentioned.

[Adhesion layer 5]
In the battery packaging material of the present invention, the adhesive layer 5 is a layer optionally provided between the barrier layer 3 and the heat-fusible resin layer 4 in order to firmly bond them.

The adhesive layer 5 is made of a resin capable of bonding the barrier layer 3 and the heat-fusible resin layer 4 together. As the resin used to form the adhesive layer 5, the same adhesives as those exemplified for the adhesive layer 2 can be used in terms of the adhesive mechanism, the types of adhesive components, and the like. As the resin used to form the adhesive layer 5, polyolefin-based resins such as polyolefins, cyclic polyolefins, carboxylic acid-modified polyolefins, and carboxylic acid-modified cyclic polyolefins exemplified for the heat-sealable resin layer 4 can also be used. . From the viewpoint of excellent adhesion between the barrier layer 3 and the heat-fusible resin layer 4, the polyolefin is preferably carboxylic acid-modified polyolefin, and particularly preferably carboxylic acid-modified polypropylene. That is, the resin forming the adhesive layer 5 may or may not contain a polyolefin skeleton, and preferably contains a polyolefin skeleton. Whether the resin constituting 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 maleic anhydride-modified polyolefin is measured by infrared spectroscopy, peaks derived from maleic anhydride are detected near wavenumbers of 1760 cm ⁻¹ and 1780 cm ⁻¹ . However, if the degree of acid denaturation is low, the peak may be too small to be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

Furthermore, from the viewpoint of making the battery packaging material excellent in shape stability after molding while reducing the thickness of the battery packaging material, the adhesive layer 5 is made of a resin composition containing an acid-modified polyolefin and a curing agent. It may be a cured product. As the acid-modified polyolefin, the same carboxylic acid-modified polyolefin and carboxylic acid-modified cyclic polyolefin exemplified for the heat-sealable resin layer 4 can be preferably exemplified.

Moreover, the curing agent is not particularly limited as long as it cures the acid-modified polyolefin. Examples of curing agents include epoxy-based curing agents, polyfunctional isocyanate-based curing agents, carbodiimide-based curing agents, and oxazoline-based curing agents.

The epoxy-based curing agent is not particularly limited as long as it is a compound having at least one epoxy group. Examples of epoxy-based curing agents include epoxy resins such as bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolac glycidyl ether, glycerin polyglycidyl ether, and polyglycerin polyglycidyl ether.

The polyfunctional isocyanate-based curing agent is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of polyfunctional isocyanate curing agents include isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), polymers and nurates thereof, and Mixtures and copolymers with other polymers may be mentioned.

The carbodiimide-based curing agent is not particularly limited as long as it is a compound having at least one carbodiimide group (-N=C=N-). As the carbodiimide curing agent, a polycarbodiimide compound having at least two carbodiimide groups is preferred.

The oxazoline-based curing agent is not particularly limited as long as it is a compound having an oxazoline skeleton. Specific examples of oxazoline-based curing agents include Epocross series manufactured by Nippon Shokubai Co., Ltd., and the like.

From the viewpoint of enhancing the adhesion between the barrier layer 3 and the heat-fusible resin layer 4 by the adhesive layer 5, the curing agent may be composed of two or more kinds of compounds.

The content of the curing agent in the resin composition forming the adhesive layer 5 is preferably in the range of about 0.1 to 50% by mass, more preferably in the range of about 0.1 to 30% by mass. More preferably, it is in the range of about 0.1 to 10% by mass.

The thickness of the adhesive layer 5 is not particularly limited as long as it functions as an adhesive layer. Up to about 5 μm can be mentioned. In the case of using the resin exemplified for the heat-fusible resin layer 4, the thickness is preferably about 2 to 50 μm, more preferably about 10 to 40 μm. In the case of a cured product of an acid-modified polyolefin and a curing agent, the thickness is preferably 30 μm or less, more preferably about 0.1 to 20 μm, still more preferably about 0.5 to 5 μm. When the adhesive layer 5 is a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, the adhesive layer 5 can be formed by applying the resin composition and curing it by heating or the like.

3. Method for Producing Battery Packaging Material The method for producing the battery packaging material of the present invention is not particularly limited as long as a laminate obtained by laminating each layer having a predetermined composition can be obtained. That is, as the base material layer 1, prepare a material having at least a polyamide resin layer 1a, an adhesive resin layer 1b, and a polyester resin layer 1c in this order, together with a barrier layer 3 and a heat-fusible resin layer 4. By laminating the above, the battery packaging material of the present invention can be obtained.

An example of the method for producing the battery packaging material of the present invention is as follows. First, a laminate (hereinafter also referred to as "laminate A") is formed by sequentially laminating a substrate layer 1, an adhesive layer 2 provided as necessary, and a barrier layer 3. Specifically, the laminate A is formed by applying an adhesive used for forming the adhesive layer 2 on the substrate layer 1 or on the barrier layer 3 whose surface is chemically treated as necessary, by a gravure coating method, After coating and drying by a coating method such as a roll coating method, the barrier layer 3 or the base material layer 1 is laminated and the adhesive layer 2 is cured by a dry lamination method.

Next, on the barrier layer 3 of the laminate A, the heat-fusible resin layer 4 is laminated. When the heat-fusible resin layer 4 is directly laminated on the barrier layer 3, the resin component constituting the heat-fusible resin layer 4 is applied onto the barrier layer 3 of the laminate A by a gravure coating method or a roll coating method. It may be applied by a method such as the following. When the adhesive layer 5 is provided between the barrier layer 3 and the heat-fusible resin layer 4, for example, (1) the adhesive layer 5 and the heat-fusible resin layer are placed on the barrier layer 3 of the laminate A. 4 (co-extrusion lamination method); (3) a method of extruding or solution-coating an adhesive for forming an adhesive layer 5 on the barrier layer 3 of the laminate A, followed by drying and baking at a high temperature; (4) The barrier layer 3 of the laminate A and the barrier layer 3 of the laminated body A, which is laminated in advance in a sheet form A method of laminating the laminate A and the heat-fusible resin layer 4 via the adhesive layer 5 while pouring the melted adhesive layer 5 between the formed heat-fusible resin layer 4 (sandwich lamination method). etc.

As described above, the substrate layer 1/optionally provided adhesive layer 2/optionally chemically treated barrier layer 3/optionally provided adhesive layer 5/thermal fusion bondability A laminate consisting of the resin layer 4 is formed, and in order to strengthen the adhesiveness of the adhesive layer 2 and the adhesive layer 5 provided as necessary, a hot roll contact type, hot air type, near infrared type Or you may use for heat processing, such as a far-infrared type. Conditions for such heat treatment include, for example, 150° C. to 250° C. for 1 minute to 5 minutes.

In the battery packaging material of the present invention, each layer constituting the laminate, if necessary, improves or stabilizes film formability, lamination processing, final product secondary processing (pouching, embossing) aptitude, etc. For this purpose, surface activation treatment such as corona treatment, blast treatment, oxidation treatment and ozone treatment may be applied.

4. Use of Battery Packaging Material The battery packaging material of the present invention is used as a package for hermetically housing battery elements such as a positive electrode, a negative electrode and an electrolyte. That is, a battery can be made by housing a battery element comprising at least a positive electrode, a negative electrode, and an electrolyte in a package formed of the battery packaging material of the present invention.

Specifically, a battery element comprising at least a positive electrode, a negative electrode, and an electrolyte is wrapped in the battery packaging material of the present invention in a state in which metal terminals connected to the positive electrode and the negative electrode protrude outward. The peripheral edge of the element is coated so as to form a flange portion (area where the heat-fusible resin layers contact each other), and the heat-fusible resin layers of the flange portion are heat-sealed to seal the battery. A battery using the packaging material for a battery is provided. When a battery element is housed in a package formed of the battery packaging material of the present invention, the heat-sealable resin portion of the battery packaging material of the present invention should face the inside (the surface in contact with the battery element). to form a package.

The battery packaging material of the present invention may be used for either primary batteries or secondary batteries, preferably for secondary batteries. The type of secondary battery to which the battery packaging material of the present invention is applied is not particularly limited. Examples include iron storage batteries, nickel/zinc storage batteries, silver oxide/zinc storage batteries, metal-air batteries, polyvalent cation batteries, capacitors, capacitors, and the like. Among these secondary batteries, lithium-ion batteries and lithium-ion polymer batteries can be cited as suitable targets for application of the battery packaging material of the present invention.

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples. However, the present invention is not limited to the examples.

(Example 1-8 and Comparative Example 1-10)
<Manufacturing of packaging materials for batteries>
A substrate layer, a barrier layer, an adhesive layer, and a heat-fusible resin layer were laminated so as to form a laminated structure shown in Table 1 to produce a battery packaging material. In addition, in the laminated structure shown in Table 1, the numerical value means the thickness (μm) of each layer, and for example, “PET5” means polyethylene terephthalate with a thickness of 5 μm. In Table 1, PET is polyethylene terephthalate, AD is an adhesive resin layer, ONY is oriented nylon, in the lamination process, DL is an adhesive layer or adhesive layer formed by a dry lamination method, ALM is aluminum foil, PP is polypropylene, and CPP. means unstretched polypropylene, PPa means maleic anhydride-modified polypropylene, and PEN means polyethylene naphthalate.

First, an aluminum foil (40 μm thick) as a barrier layer was laminated on the substrate layer by a dry lamination method. Specifically, a two-part urethane adhesive (polyol compound and aromatic isocyanate compound) is applied to one side of the barrier layer with an acid-resistant film formed on the surface, and an adhesive layer (thickness 3 μm) was formed. Next, after the adhesive layer on the barrier layer and the polyamide resin layer side of the base layer are laminated by a dry lamination method, an aging treatment is performed to obtain a base layer/adhesive layer/barrier layer laminate. was made.

Next, in Examples 1, 3, 5, 7 and Comparative Examples 1, 3, 5, 7, 9, an anhydrous adhesive layer was applied on the barrier layer (acid-resistant coating) of each laminate obtained. By melt co-extrusion of maleic acid-modified polypropylene and polypropylene as a heat-fusible resin layer, an adhesive layer and a heat-fusible resin layer are laminated on the surface of the barrier layer to form a substrate layer/adhesive layer/barrier layer. A battery packaging material was obtained in which the /adhesive layer/heat-fusible resin layer was laminated in this order.

On the other hand, in Examples 2, 4, 6, 8 and Comparative Examples 2, 4, 6, 8, 10, the barrier layer (acid-resistant layer) of each laminate of base layer/adhesive layer/barrier layer obtained above A two-component urethane adhesive (a polyol compound and an aromatic isocyanate compound) was applied onto the adhesive film) to form an adhesive layer (3 μm thick) on the aluminum foil. Next, after laminating the adhesive layer on the barrier layer and the unstretched polypropylene by a dry lamination method, an aging treatment is performed to obtain a substrate layer/adhesive layer/barrier layer/adhesive layer/heat-fusible resin layer. was laminated in order to obtain a battery packaging material.

<Evaluation of electrolyte resistance>
Each battery packaging material obtained above was cut to prepare a test piece of 100 mm×100 mm, which was used as a test sample. 1 mol of lithium hexafluorophosphate in an electrolyte (ethylene carbonate: diethyl carbonate: dimethyl carbonate = 1:1:1 (volume ratio)) was applied to the surface of the test sample on the substrate layer side in a room temperature (25 ° C.) environment. was added dropwise, and the mixture was left for 1 hour. After that, the electrolytic solution was wiped off with a rag, and it was visually observed whether or not the surface of the substrate layer was whitened. A case where whitening did not occur was judged as A, and a case where whitening had occurred was judged as C. Table 1 shows the results.

<Lamination times>
Table 1 shows the number of times each layer was laminated in the production of the battery packaging material. In Examples 1, 3, 5, 7 and Comparative Examples 1, 3, 5, 7, and 9, a lamination step by a dry lamination method between the substrate layer and the barrier layer, and an adhesive layer and a heat-melting layer to the barrier layer. Two lamination processes are carried out by a lamination process by a melt co-extrusion method for the adhesive resin layer. Further, in Examples 2, 4, 6, 8 and Comparative Examples 2, 4, 6, 8, a lamination step by a dry lamination method between the base material layer and the barrier layer, and a laminate between the barrier layer and the unstretched polypropylene film The lamination process is carried out twice by the dry lamination method.

<Measurement of Impact Strength (J)>
The impact strength (J) of each battery packaging material obtained above was measured from the substrate layer side in accordance with ASTM D3420. As a measuring instrument, a film impact tester manufactured by Toyo Seiki Co., Ltd. was used, and an impact head with a hemispherical tip having a smooth surface with a radius of 12.7 mm was used. A sample cut to a diameter of 100 mm was used for the measurement of impact strength. The sample was clamped between two plates with a circular opening of 89±0.5 mm diameter in the center. Each sample was measured three times, and the average value was taken as the impact strength of each sample. The measurement was performed in an environment of temperature 23±2° C. and relative humidity 50±5%. Table 1 shows the results.

<Measurement of Layer Thickness of Laminate>
The total thickness of the laminate constituting each battery packaging material obtained above was measured using a Mitutoyo microgauge. Table 1 shows the results. Since the thickness of each laminate in Examples and Comparative Examples is different, the value (J/μm) obtained by dividing the impact strength measured by the above method by the thickness (μm) of each laminate is shown in Table 1. Indicated.

As is clear from the results shown in Table 1, the substrate layer includes, in order from the barrier layer side, a polyamide resin layer, an adhesive resin layer, and a polyester resin layer, and the thickness of the polyester resin layer is 6 μm or less. Furthermore, in accordance with the provisions of ASTM D3420, the value obtained by dividing the impact strength (J) measured from the base layer side of the laminate by the thickness (μm) of the laminate is 0.015J. /μm or more, the battery packaging materials of Examples 1 to 8 have high impact resistance and electrolyte solution resistance.

In addition, in Comparative Examples 6 and 8, which have relatively large thicknesses, the impact strength is also a large value, but in Examples 3, 4, 7, and 8, which have the same thickness, even more than Comparative Examples 6 and 8. It had great impact strength.

<Measurement of Hardness of Each Layer in Example 4>
As an apparatus, a nanoindenter ("TriboIndenter TI950" manufactured by HYSITRON) is used.As an indenter for the nanoindenter, a Berkovich indenter (triangular pyramid) is used. First, relative humidity is 50%, 23 ℃ environment, the indenter is applied to the surface of the adhesive layer of the battery packaging material (the surface where the adhesive layer is exposed, perpendicular to the stacking direction of each layer), and the surface is pressed for 10 seconds. The indenter was pressed into the adhesive layer with a load of 40 μN from the maximum load P _max (μN) and the contact projected area A at the maximum depth (μm ² ), the indentation hardness (MPa) was calculated from P _max /A.The average value was used after measuring five different measurement points.The hardness of the adhesive resin layer was measured with a load of 10 μN. In addition, the polyethylene terephthalate film and the stretched nylon film as the base layer were measured in the same manner as the adhesive layer except that the load was 100 μN under the above measurement conditions. Each hardness is shown in Table 2. The surface into which the indenter is pressed was obtained by cutting in the thickness direction so as to pass through the center of the battery packaging material. This is the portion where the cross section of the target (adhesive layer, etc.) is exposed.The cutting was performed using a commercially available rotating microtome.

<Evaluation of formability>
The battery packaging material of Example 4 was cut into a rectangle of 90 mm in length (x direction)×150 mm in width (y direction) to obtain a test sample. This sample is placed in a rectangular mold (female mold, surface is JIS B 0659-1: 2002 Annex 1 (reference) with a diameter of 31.6 mm (x direction) x 54.5 mm (y direction) for comparison. The maximum height roughness (Rz nominal value) defined in Table 2 of the surface roughness standard piece is 3.2 μm. Corner R 2.0 mm, ridge R 1.0 mm) and a corresponding molding die ( Male type, the surface is JIS B 0659-1: 2002 Annex 1 (reference) The maximum height roughness (nominal value of Rz) specified in Table 2 of the surface roughness standard piece for comparison is 1.6 μm Corner R 2.0 mm, ridge R 1.0 mm), pressing pressure (surface pressure) 0.25 MPa, changing the molding depth from 0.5 mm in increments of 0.5 mm, 10 samples each was subjected to cold forming (pull-in one-stage forming). At this time, the test sample was placed on the female mold so that the heat-sealable resin layer side was positioned on the male mold side. Also, the clearance between the male and female dies was set to 0.3 mm. The sample after cold forming was illuminated with a penlight in a dark room, and it was confirmed whether or not pinholes and cracks had occurred in the aluminum foil due to the transmission of the light. The deepest molding depth at which pinholes and cracks do not occur in all 10 samples of aluminum foil is A mm, and the number of samples with pinholes etc. at the shallowest molding depth where pinholes etc. occur in aluminum foil is B A value calculated by the following formula was defined as the limit molding depth of the battery packaging material. Table 2 shows the results.
Limit molding depth = A mm + (0.5 mm / 10 pieces) x (10 pieces - B pieces)

1 base material layer 1a polyamide resin layer 1b adhesive resin layer 1c polyester resin layer 2 adhesive layer 3 barrier layer 4 heat-fusible resin layer 5 adhesive layer 10 battery packaging material

Claims (9)

Consists of a laminate comprising at least a substrate layer, a barrier layer, and a heat-fusible resin layer in this order,
The base material layer includes at least a polyamide resin layer, an adhesive resin layer, and a polyester resin layer in order from the barrier layer side,
The polyester resin layer has a thickness of 6 μm or less,
The value obtained by dividing the impact strength measured from the base layer side of the laminate by the thickness of the laminate is 0.015 J / μm or more, in accordance with the provisions of ASTM D3420. Packaging materials for batteries. An adhesive layer is provided between the base material layer and the barrier layer,
2. The battery packaging material according to claim 1, wherein each of said adhesive resin layer and said adhesive layer has a hardness of 50 MPa or less as measured by a nanoindentation method. 3. The adhesive resin layer according to claim 1 or 2, wherein the adhesive resin layer is formed of at least one selected from the group consisting of acid-modified polyolefin resins, acid-modified styrene-based elastomer resins, and acid-modified polyester-based elastomer resins. Packaging materials for batteries. The battery packaging material according to any one of claims 1 to 3, wherein the heat-fusible resin layer is made of unstretched polypropylene. 5. The battery packaging material according to claim 1, wherein the ratio of the thickness of said polyester resin layer to the thickness of said polyamide resin layer is 0.5 or less. The battery packaging material according to any one of claims 1 to 5, wherein the laminate has a thickness of 180 µm or less. The battery packaging material according to any one of claims 1 to 6, wherein the polyamide resin layer is made of nylon. The battery packaging material according to any one of claims 1 to 7, wherein the polyester resin layer is made of polyethylene terephthalate. A battery, wherein a battery element comprising 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.

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