CN111279509A

CN111279509A - Battery packaging material and battery

Info

Publication number: CN111279509A
Application number: CN201880067169.5A
Authority: CN
Inventors: 横田一彦; 津森薰; 山下孝典; 山下力也
Original assignee: Dai Nippon Printing Co Ltd
Current assignee: Dai Nippon Printing Co Ltd
Priority date: 2017-10-18
Filing date: 2018-10-18
Publication date: 2020-06-12
Also published as: JP7347628B2; WO2019078284A1; JP2023011708A; JPWO2019078284A1; JP7167930B2

Abstract

The battery packaging material of the present invention is composed of a laminate having at least a base material layer, a barrier layer and a heat-sealable resin layer in this order, wherein the base material layer has at least a polyamide resin layer, an adhesive resin layer and a polyester resin layer in this order from the side of the barrier layer, the thickness of the polyester resin layer is 6 [ mu ] m or less, and the value obtained by dividing the impact strength (J) of the laminate measured from the side of the base material layer by the thickness (μm) of the laminate is 0.015J/μm or more according to ASTM D3420.

Description

Battery packaging material and battery

Technical Field

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

Background

Various types of batteries have been developed, but in all batteries, a packaging material is an essential component for sealing battery elements such as electrodes and electrolytes. At present, a metal packaging material is generally used as a battery package.

On the other hand, in recent years, with the increase in performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, and the like, batteries are required to have various shapes, and further, to be thin and light. However, the metal-made battery packaging materials that are commonly used at present have disadvantages that it is difficult to cope with the diversification of shapes and that weight reduction is limited.

Therefore, in recent years, as a battery packaging material which can be easily processed into various shapes and can be made thinner and lighter, a film-shaped laminate in which a substrate, a barrier layer, and a heat-fusible resin layer are sequentially laminated has been proposed (for example, see patent document 1).

In such a battery packaging material, a battery in which a battery element is housed inside the battery packaging material can be obtained by forming a recess by molding, disposing a battery element such as an electrode or an electrolyte solution in a space formed by the recess, and thermally welding the thermally-weldable resin layers to each other.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2008-287971

Disclosure of Invention

Technical problem to be solved by the invention

In vehicles and mobile devices, strong impact may be applied to a battery used for a product while the product is being transported or used. When a strong impact is applied to the battery and the battery packaging material is broken, the electrolyte solution and the like may leak to the outside, and therefore, high impact resistance is required for the battery packaging material.

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

In addition, in the case where the electrolyte solution is contained in a package formed of a battery packaging material in the battery manufacturing process, the electrolyte solution may adhere to the outer surface of the battery packaging material, which discolors the surface and results in a defective product.

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

Under such circumstances, the main object of the present invention is to: provided is a battery packaging material having high impact resistance and electrolyte resistance. The invention also aims to: a battery using the battery packaging material is provided.

Technical solution for solving technical problem

The present inventors have conducted intensive studies in order to solve the above-mentioned technical problems. As a result, it was found that a battery packaging material comprising a laminate comprising at least a base layer, a barrier layer and a heat-sealable resin layer in this order, the base layer comprising at least a polyamide resin layer, an adhesive resin layer and a polyester resin layer in this order from the barrier layer side, the polyester resin layer having a thickness of 6 μm or less, and the laminate having a value of 0.015J/μm or more obtained by dividing the impact strength (J) of the laminate measured from the base layer side by the thickness (μm) of the laminate according to the specification of ASTM D3420, has high impact resistance and electrolyte solution resistance. The present invention has been completed based on these findings and further research and study.

That is, the present invention provides the following aspects of the invention.

The packaging material for a battery according to item 1, which comprises a laminate comprising at least a substrate layer, a barrier layer and a heat-sealable resin layer in this order,

the base material layer comprises at least a polyamide resin layer, an adhesive resin layer and a polyester resin layer in this order from the barrier layer side,

the thickness of the polyester resin layer is 6 μm or less,

the laminate has a value obtained by dividing the impact strength (J) of the laminate measured from the base layer side by the thickness (μm) of the laminate, which is 0.015J/μm or more, according to the ASTM D3420.

The battery packaging material according to item 1, wherein an adhesive layer is provided between the base material layer and the barrier layer,

the adhesive resin layer and the adhesive layer each have a hardness of 50MPa or less as measured by nanoindentation.

The battery packaging material according to item 1 or 2, wherein the adhesive resin layer is formed of at least 1 selected from the group consisting of an acid-modified polyolefin-based resin, an acid-modified styrene-based elastomer resin, and an acid-modified polyester-based elastomer resin.

The battery packaging material according to any one of claims 1 to 3, wherein the heat-fusible resin layer is formed of unstretched polypropylene.

The battery packaging material according to any one of claims 1 to 4, wherein a ratio of the thickness of the polyester resin layer to the thickness of the 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 of any one of claims 1 to 7, wherein the polyester resin layer is made of polyethylene terephthalate.

The battery according to item 9, wherein a battery element having at least a positive electrode, a negative electrode, and an electrolyte is contained in a package formed of the battery packaging material according to any one of items 1 to 8.

Effects of the invention

The present invention can provide a battery packaging material having high impact resistance and electrolyte resistance. The present invention can also provide a battery using the battery packaging material.

Drawings

Fig. 1 is a schematic diagram showing an example of a cross-sectional structure of a battery packaging material of the present invention.

Fig. 2 is a schematic diagram showing an example of a cross-sectional structure of the battery packaging material of the present invention.

Fig. 3 is a schematic diagram showing an example of a cross-sectional structure of the battery packaging material of the present invention.

Detailed Description

The battery packaging material of the present invention is composed of a laminate having at least a base material layer, a barrier layer, and a heat-sealable resin layer in this order. The base material layer has at least a polyamide resin layer, an adhesive resin layer, and a polyester resin layer in this order from the barrier layer side. The thickness of the polyester resin layer is 6 μm or less. Further, the value obtained by dividing the impact strength (J) of the laminate measured from the base layer side by the thickness (μm) of the laminate is 0.015J/μm or more in accordance with the specification of ASTM D3420. The battery packaging material of the present invention can have high impact resistance and electrolyte resistance by having such a configuration. The battery packaging material of the present invention will be described in detail below.

In the present specification, the numerical ranges indicated by "to" mean "above" and "below". For example, a mark of 2 to 15mm means 2mm to 15 mm.

1. Laminate structure and physical properties of battery packaging material

As shown in fig. 1, a battery packaging material 10 of the present invention includes a laminate having at least a base material layer 1, a barrier layer 3, and a heat-fusible resin layer 4 in this order. The base material 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.

In the battery packaging material of the present invention, the polyester resin layer 1c of the base 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-fusible resin layers 4 located at the peripheral edges of the battery element are heat-fused to each other to seal the battery element, whereby the battery element is sealed.

In the battery packaging material 10 of the present invention, as shown in fig. 2 and 3, an adhesive layer 2 may be provided between the base material layer 1 and the barrier layer 3 as needed for the purpose of improving the adhesiveness therebetween. As shown in fig. 3, an adhesive layer 5 may be provided between the barrier layer 3 and the heat-fusible resin layer 4 as needed for the purpose of improving the adhesiveness therebetween.

The battery packaging material of the present invention is characterized in that: a value P obtained by dividing the impact strength (J) measured from the substrate layer 1 side of a laminate constituting a packaging material for a battery by the thickness (μm) of the laminate is 0.015J/μm or more in accordance with the specification of ASTM D3420. The substrate layer 1 of the battery packaging material of the present invention has at least the polyamide resin layer 1a, the adhesive resin layer 1b, and the polyester resin layer 1c in this order from the barrier layer 3 side, and has such characteristics that high impact resistance and high electrolyte resistance can be exhibited even if the thickness of the polyester resin layer is set to 6 μm or less. As the impact head of the measuring apparatus, a tip hemispherical member having a radius of 12.7mm and a smooth surface was used. The impact strength was measured by using a laminate cut to a diameter of 100mm as a sample. The sample was held between 2 plates with a circular opening of 89. + -. 0.5mm diameter in the center.

From the viewpoint of further improving the impact resistance, the lower limit of the value P obtained by dividing the impact strength (J) measured from the substrate layer 1 side of the laminate constituting the battery packaging material by the thickness (μm) of the laminate is preferably about 0.015J/μm or more, more preferably about 0.016J/μm or more; the upper limit is preferably about 0.020J/μm or less, more preferably about 0.019J/μm or less. Preferable ranges of the value P include about 0.015 to 0.020J/μm, about 0.015 to 0.019J/μm, about 0.016 to 0.020J/μm, and about 0.016 to 0.019J/μm.

As a method of setting the value P to the above value, the following method may be employed: as the substrate layer 1, a substrate layer having 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 is used, and after the thickness of the polyester resin layer 1c is set to 6 μm or less, the material and thickness of each layer described later are adjusted.

In the battery packaging material of the present invention, the impact strength (J) may be preferably 1.4J or more, more preferably 1.6J or more, and still more preferably 1.7J or more, considering the relationship with the thickness of the laminate constituting the battery packaging material, as long as the value P is satisfied. Examples of the upper limit of the impact strength (J) include 3.0J and 2.8J.

The thickness of the laminate constituting the battery packaging material 10 of the present invention is not particularly limited, and from the viewpoint of suppressing an increase in the thickness of the battery packaging material and imparting high impact resistance, for example, it is about 180 μm or less, preferably about 160 μm or less, more preferably about 60 to 180 μm, further preferably about 60 to 160 μm, further preferably about 80 to 160 μm, and particularly preferably about 100 to 160 μm.

2. Each layer forming the packaging material for batteries

[ base Material layer 1]

In the battery packaging material 10 of the present invention, the base material layer 1 is a layer located on the outermost layer side. The base material 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.

The polyamide resin layer 1a is a layer made of polyamide, and is made of polyamide, and thus has the effects of imparting toughness and improving moldability of the battery packaging material 10, and can also impart flexibility, puncture resistance, and cold resistance. In the present invention, the polyamide resin layer 1a is located on the barrier layer 3 side of the base material layer 1, and ensures the high impact resistance of the present invention together with the polyester resin layer 1 c.

Specific examples of the polyamide include: aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and copolymers of nylon 6 and nylon 66; hexamethylenediamine-isophthalic acid-terephthalic acid copolymerized polyamides such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (I represents isophthalic acid and T represents terephthalic acid) containing a structural unit derived from terephthalic acid and/or isophthalic acid, aromatic polyamides such as polymetaxylyleneadipamide (MXD6), and the like; alicyclic polyamides such as polyaminomethylcyclohexyl adipic acid amide (PACM 6); polyamide obtained by copolymerizing a lactam component and an isocyanate component such as 4, 4' -diphenylmethane-diisocyanate, and polyester amide copolymers and polyether ester amide copolymers which are copolymers of a copolymerized polyamide with polyester and polyalkylene ether glycol; copolymers thereof, and the like. These polyamides may be used alone in 1 kind, or may be used in combination of 2 or more kinds. The stretched polyamide film has excellent stretchability, and can prevent whitening due to resin breakage of the base layer 1 during molding, and is suitable for use as a material for forming the polyamide resin layer 1 a.

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

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

The polyester resin layer 1c is a layer made of polyester. The polyester resin layer 1c 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. In addition, as described above, the polyester resin layer 1c ensures the high impact resistance of the present invention together with the polyamide resin layer 1 a.

Specific examples of the polyester include: polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, a copolyester mainly composed of ethylene terephthalate as a repeating unit, a copolyester mainly composed of butylene terephthalate as a repeating unit, and the like. Further, as the copolyester mainly containing ethylene terephthalate as a repeating unit, there can be specifically mentioned: a copolymer polyester obtained by polymerizing ethylene terephthalate as a main repeating unit with ethylene isophthalate (hereinafter, referred to as polyethylene glycol (terephthalate/isophthalate)), polyethylene glycol (terephthalate/isophthalate), polyethylene glycol (terephthalate/adipate), polyethylene glycol (sodium terephthalate/isophthalate sulfonate), polyethylene glycol (sodium terephthalate/isophthalate), polyethylene glycol (terephthalate/phenyl-dicarboxylate), polyethylene glycol (terephthalate/decanedicarboxylate), and the like. Specific examples of the copolyester mainly composed of butylene terephthalate as a repeating unit include a copolyester mainly composed of butylene terephthalate as a repeating unit and polymerized with butylene isophthalate (hereinafter, referred to as polybutylene terephthalate/isophthalate), polybutylene terephthalate/adipate, polybutylene terephthalate/sebacate, polybutylene terephthalate/decanedioate, and polybutylene naphthalate. These polyesters may be used alone in 1 kind, or 2 or more kinds may be used in combination. The polyester has an excellent electrolyte resistance and has an advantage that whitening or the like is less likely to occur on adhesion to an electrolyte.

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

The thickness of the polyester resin layer 1c may be 6 μm or less, and from the viewpoint of suppressing an increase in the thickness of the battery packaging material and imparting high impact resistance and electrolyte resistance, the thickness of the polyester resin layer 1c is preferably about 1 to 6 μm, and more preferably about 1 to 5 μm.

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

The adhesive resin layer 1b is a layer made of a resin that adheres the polyamide resin layer 1a and the polyester resin layer 1 c. The bonding mechanism of the adhesive is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a hot melt type, a hot press 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 as measured by the nanoindentation method is preferably 50MPa or less. In the battery packaging material of the present invention, excellent moldability can be exhibited when the above hardness of the adhesive resin layer 1b is 50MPa or less, and the hardness of the adhesive layer 2 described later, which is located between the base material layer 1 and the barrier layer 3, is also 50MPa or less as measured by the nanoindentation method. This mechanism can be considered, for example, as follows. That is, it is considered that since the hardness of these layers is designed to be smaller than that of a normal adhesive, although the base layer 1 has the polyester resin layer 1c (polyester resin is generally harder than polyamide resin such as nylon and is inferior in moldability), the adhesive resin layer 1b and the adhesive layer 2 can suitably suppress rapid deformation of the barrier layer 3 due to deformation of the base layer 1 at the time of molding, and as a result, generation of cracks or pinholes in the barrier layer 3 can be effectively suppressed.

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

In the present invention, the hardness of the adhesive resin layer 1b and the adhesive layer 2 measured by nanoindentation method are respectively in accordance withThe following procedure was performed to obtain values. As an apparatus, a nanoindenter ("TriboInducer TI 950" manufactured by HYSITRON corporation) was used as a indenter of the nanoindenter, a Berkovich indenter (triangular pyramid) was used, the indenter was brought into contact with the surface of the adhesive layer 2 (the surface on which the adhesive layer 2 was exposed, in a direction perpendicular to the laminating direction of the respective layers) of the battery packaging material with respect to the hardness of the adhesive layer 2 in an environment of a relative humidity of 50% and 23 ℃, the pressure was applied from the surface to the adhesive layer for 10 seconds while maintaining the pressure for 40. mu.N, the pressure was applied for 5 seconds, then the load was removed for 10 seconds, and the maximum load P was used_max(μ N) and projected area of contact A (μm) at maximum depth²) By the use of P_maxThe indentation hardness (MPa) was calculated. The hardness of the adhesive resin layer 1b can be measured in the same manner as the adhesive layer 2, except that the load is 10 μ N.

The adhesive used to form the adhesive resin layer 1b is preferably a resin composition containing a modified thermoplastic resin, which is graft-modified with an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative component. The modified thermoplastic resin is preferably a resin obtained by modifying a polyolefin resin, a styrene elastomer, a polyester elastomer, or the like with an unsaturated carboxylic acid derivative component. The resin can be used alone in 1, also can be used in 2 or more combinations. Examples of the unsaturated carboxylic acid derivative component include an anhydride of an unsaturated carboxylic acid and an ester of an unsaturated carboxylic acid. The unsaturated carboxylic acid derivative component may be used alone in 1 kind, or may be used in combination with 2 or more kinds.

Examples of the polyolefin resin in the modified thermoplastic resin include low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene- α olefin copolymer, homopolypropylene, block polypropylene or random polypropylene, propylene- α olefin copolymer, copolymer obtained by copolymerizing polar molecules such as acrylic acid and methacrylic acid with the above-mentioned materials, and polymer such as crosslinked polyolefin, and the polyolefin resin may be 1 kind alone or 2 or more kinds in combination.

Examples of the styrene-based elastomer in the modified thermoplastic resin include copolymers of styrene (hard segment) and butadiene or isoprene or hydrides thereof (soft segment). The polyolefin-based resin may be 1 kind alone or 2 or more kinds in combination.

Examples of the polyester elastomer in the modified thermoplastic resin include copolymers of a crystalline polyester (hard segment) and a polyalkylene ether glycol (soft segment). The polyolefin-based resin may be 1 kind alone or 2 or more kinds in combination.

Examples of the unsaturated carboxylic acid in the modified thermoplastic resin 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. Examples of the acid anhydride of the unsaturated carboxylic acid include maleic anhydride, itaconic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, bicyclo [2,2,1] hept-2-ene-5, 6-dicarboxylic anhydride, and the like. Examples of the ester of an unsaturated carboxylic acid include esters of unsaturated carboxylic acids such as methyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dimethyl maleate, monomethyl maleate, diethyl fumarate, dimethyl itaconate, diethyl citraconate, dimethyl tetrahydrophthalate, and dimethyl bicyclo [2,2,1] hept-2-ene-5, 6-dicarboxylate.

The modified thermoplastic resin can be obtained by heating and reacting 0.2 to 100 parts by mass of the unsaturated carboxylic acid derivative component with 100 parts by mass of a thermoplastic resin as a matrix in the presence of a radical initiator.

The reaction temperature is preferably 50 to 250 ℃, and more preferably 60 to 200 ℃. The reaction time also depends on the production method, and the residence time in the extruder during the melt grafting reaction using the twin-screw extruder is preferably 2 to 30 minutes, more preferably 5 to 10 minutes. The modification reaction may be carried out under any conditions of normal pressure and increased pressure.

Examples of the radical initiator used in the modification reaction include organic peroxides. As the organic peroxide, various materials can be selected depending on the temperature conditions and the reaction time, and examples thereof include alkyl peroxides, aryl peroxides, acyl peroxides, ketone peroxides, peroxyketals, peroxycarbonates, peroxyesters, and hydrogen peroxide. In the case of the above melt grafting reaction using a twin-screw extruder, alkyl peroxides, peroxyketals, peroxyesters are preferred, and di-t-butyl peroxide, 2, 5-dimethyl-2, 5-di-t-butylperoxy-hexyne-3, dicumyl peroxide are more preferred.

The hardness of the adhesive resin layer 1b may be adjusted to the above value by adjusting not only the kind of resin contained in the adhesive but also the molecular weight of the resin, the number of crosslinking points, the modification ratio, the elongation ratio, the stretching temperature, and the like.

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 400MPa, and more preferably about 300 to 350 MPa. Further, the hardness of the polyamide resin layer 1a measured by the nanoindentation method is preferably about 200 to 400MPa, and 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 can be measured in the same manner as the adhesive resin layer 1b except that the polyester resin layer 1c or the polyamide resin layer 1a is used as the object of hardness measurement and the press-in load is set to 100 μ N in the above-described method for measuring the hardness of the adhesive resin layer 1 b.

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

The base material layer 1 may have other layers in addition to the polyamide resin layer 1a, the adhesive resin layer 1b, and the polyester resin layer 1 c. Examples of the material constituting the other layer include epoxy resin, acrylic resin, fluorine resin, polyurethane, silicone resin, phenol resin, polyetherimide, polyimide, and a mixture or copolymer thereof. The polyamide resin layer 1a, the adhesive resin layer 1b, and the polyester resin layer 1c may be a single layer or a plurality of layers.

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 on the side of the base material layer 1. The lubricant is not particularly limited, but preferably includes an amide-based lubricant. Specific examples of the amide-based lubricant include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, and unsaturated fatty acid bisamides. Specific examples of the saturated fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, and hydroxystearic acid amide. Specific examples of the unsaturated fatty acid amide include oleamide and erucamide. Specific examples of the substituted amide include N-oleyl palmitamide, N-stearyl stearamide, N-stearyl oleamide, N-oleyl stearamide, and N-stearyl erucamide. Specific examples of the methylolamide include methylolstearic acid amide. Specific examples of the saturated fatty bisamide include methylene bisstearamide, ethylene bisdecanoic acid amide, ethylene bislauric acid amide, ethylene bisstearamide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearamide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N '-distearyladipic acid amide, N' -distearylsebacic acid amide, and the like. Specific examples of the unsaturated fatty bisamide include ethylene bisoleamide, ethylene biserucamide, hexamethylene bisoleamide, N '-dioleyl adipic acid amide, and N, N' -dioleyl sebacic acid amide. Specific examples of the fatty acid ester amide include stearic acid amide ethyl stearate. Specific examples of the aromatic bisamide include m-xylylene bisstearamide, m-xylylene bishydroxystearamide, and N, N' -distearyl isophthalic acid amide. The lubricant may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

When the lubricant is present on the surface of the substrate layer 1 side, the amount of the lubricant present is not particularly limited, and is preferably about 3mg/m in an environment having a temperature of 24 ℃ and a relative humidity of 60%²More preferably 4 to 15mg/m²About, preferably 5 to 14mg/m²Left and right.

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

[ 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 needed to firmly adhere them.

The adhesive layer 2 is formed of an adhesive capable of bonding the base layer 1 and the barrier layer 3. The adhesive used to form the adhesive layer 2 may be a two-component curing adhesive or a one-component curing adhesive. The bonding mechanism of the adhesive for forming the adhesive layer 2 is not particularly limited, and may be any of a chemical reaction type, a solvent volatilization type, a hot melt type, a hot press type, and the like.

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

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

The hardness of the adhesive layer 2 can be adjusted to the above-mentioned value by adjusting not only the kind of the resin contained in the adhesive but also the molecular weight of the resin and the number of crosslinking points, the ratio of the main agent to the curing agent, the dilution ratio of the main agent to the curing agent, the drying temperature, the curing time, and the like.

Specific examples of the 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, and copolyester; a polyether adhesive; a polyurethane adhesive; an epoxy resin; a phenolic resin-based resin; polyamide resins such as nylon 6, nylon 66, nylon 12, and copolyamide; polyolefin resins such as polyolefin, carboxylic acid-modified polyolefin, and metal-modified polyolefin, and polyvinyl acetate resins; a cellulose-based binder; (meth) acrylic resins; a polyimide-based resin; a polycarbonate; amino resins such as urea resins and melamine resins; rubbers such as chloroprene rubber, nitrile rubber, and styrene-butadiene rubber; silicone resins, and the like. These adhesive components can be used alone in 1 kind, can also be used in 2 or more combinations. Among these adhesive components, a polyurethane adhesive is preferably used.

The thickness of the adhesive layer 2 is not particularly limited as long as it can function as an adhesive layer, and may be, for example, about 1 to 10 μm, preferably about 2 to 5 μm.

[ Barrier layer 3]

In the battery packaging material of the present invention, the barrier layer 3 is a layer having a function of improving the strength of the battery packaging material and preventing water vapor, oxygen, light, and the like from entering the battery. The barrier layer 3 may be formed of a metal foil, a metal vapor-deposited film, an inorganic oxide vapor-deposited film, a carbon-containing inorganic oxide vapor-deposited film, a film provided with these vapor-deposited layers, or the like, and is preferably a layer formed of a metal foil. Specific examples of the metal constituting the barrier layer include aluminum, stainless steel, and titanium, and aluminum is preferably used. In the production of the battery packaging material, the barrier layer is more preferably formed of, for example, a soft aluminum foil such as annealed aluminum (JIS H4160: 1994A 8021H-O, JIS H4160: 1994A 8079H-O, JIS H4000: 2014A 8021P-O, JIS H4000: 2014A 8079P-O) from the viewpoint of preventing the occurrence of wrinkles and pinholes in the barrier layer 3.

The thickness of the barrier layer 3 is not particularly limited as long as it can function as a barrier layer for water vapor or the like, and examples thereof include preferably about 100 μm or less, more preferably about 10 to 100 μm, and further preferably about 10 to 80 μm.

In addition, at least one surface, preferably both surfaces, of the barrier layer 3 are preferably subjected to chemical conversion treatment for stabilization of adhesion, prevention of dissolution, corrosion, and the like. The chemical conversion treatment is a treatment for forming an acid-resistant coating on the surface of the barrier layer. The chemical conversion treatment includes, for example: chromate treatment using chromium compounds such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium dihydrogen phosphate, chromic acid acetoacetate, chromium chloride, and chromium potassium sulfate; phosphoric acid treatment using a phosphoric acid compound such as sodium phosphate, potassium phosphate, ammonium phosphate, or polyphosphoric acid; chemical conversion treatment using an aminated phenol polymer having a repeating unit represented by the following general formulae (1) to (4). In the aminated phenol polymer, the repeating units represented by the following general formulae (1) to (4) may be contained in 1 kind alone, or may be contained in any combination of 2 or more kinds.

In the general formulae (1) to (4), X represents a hydrogen atom, a hydroxyl group, an alkyl group, a hydroxyalkyl group, an allyl group or a benzyl group. In addition, R¹And R²The same or different from each other, represent a hydroxyl group, an alkyl group or a hydroxyalkyl group. X, R in the general formulae (1) to (4)¹And R²Examples of the alkyl group include a linear or branched alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group. In addition, as X, R¹And R²Hydroxyalkyl groups shown, for example, can beExamples of the alkyl group include a straight-chain or branched-chain alkyl group having 1 to 4 carbon atoms, which is substituted with 1 hydroxyl group, such as a hydroxymethyl group, a 1-hydroxyethyl group, a 2-hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group, a 3-hydroxypropyl group, a 1-hydroxybutyl group, a 2-hydroxybutyl group, a 3-hydroxybutyl group, or a 4-hydroxybutyl group. X, R in the general formulae (1) to (4)¹And R²The alkyl and hydroxyalkyl groups shown may be the same or different from each other. In the general formulae (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 formulae (1) to (4) is, for example, preferably about 500 to 100 ten thousand, and more preferably about 1000 to 2 ten thousand.

As a chemical conversion treatment method for imparting corrosion resistance to the barrier layer 3, the following method can be mentioned: an acid-resistant coating film is formed on the surface of the barrier layer 3 by coating a material obtained by dispersing fine particles of a metal oxide such as aluminum oxide, titanium oxide, cerium oxide, or tin oxide or barium sulfate in phosphoric acid and then sintering the coated material at 150 ℃ or higher. Further, a resin layer obtained by crosslinking a cationic polymer with a crosslinking agent may be further formed on the acid-resistant coating film. Among them, examples of the cationic polymer include polyethyleneimine, an ionic polymer complex comprising polyethyleneimine and a polymer having a carboxylic acid, a primary amine-grafted acrylic resin obtained by graft-polymerizing a primary amine onto an acrylic backbone, polyallylamine or a derivative thereof, and aminophenol. These cationic polymers may be used alone in 1 kind, or 2 or more kinds may be used in combination. Examples of the crosslinking agent include compounds having at least 1 functional group selected from the group consisting of an isocyanate group, a glycidyl group, a carboxyl group and an oxazoline group, and silane coupling agents. These crosslinking agents may be used alone in 1 kind, or 2 or more kinds may be used in combination.

As a specific method for providing the acid-resistant coating film, for example, a method of degreasing at least the surface of the inner layer side of the aluminum foil by a known treatment method such as an alkali immersion method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, or an acid activation method, and then applying a treatment liquid (aqueous solution) containing a metal phosphate such as a chromium phosphate, a titanium phosphate, a zirconium phosphate, or a zinc phosphate and a mixture of these metal salts as a main component to the degreased surface by a known application method such as a roll coating method, a gravure printing method, or an immersion method; or a treatment liquid (aqueous solution) containing a nonmetallic phosphate salt and a mixture of these nonmetallic salts as main components; or a mixture of these and an aqueous synthetic resin such as an acrylic resin, a phenolic resin, or a urethane resin (aqueous solution), whereby an acid-resistant coating film can be formed. For example, when the treatment is performed with a chromium phosphate treatment liquid, an acid-resistant coating film containing chromium phosphate, aluminum oxide, aluminum hydroxide, aluminum fluoride, or the like is formed; when treated with a zinc phosphate-based treatment liquid, an acid-resistant coating film containing zinc phosphate hydrate, aluminum phosphate, alumina, aluminum hydroxide, aluminum fluoride, or the like is formed.

As another specific example of the method for providing the acid-resistant coating, for example, the acid-resistant coating can be formed by degreasing at least the surface of the inner layer side of the aluminum foil by a known treatment method such as an alkali immersion method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, or an acid activation method, and then subjecting the degreased surface to a known anodic oxidation treatment.

As another example of the acid-resistant coating, a phosphate-based coating or a chromic acid-based coating may be mentioned. Examples of the phosphate system include zinc phosphate, iron phosphate, manganese phosphate, calcium phosphate, and chromium phosphate; examples of the chromic acid series include chromic chromate.

As another example of the acid-resistant coating, a phosphate, chromate, fluoride, triazine thiol compound, or the like can be formed to exhibit the following effects: the delamination between the aluminum and the base material layer is prevented during the embossing molding; prevent dissolution and corrosion of the aluminum surface, particularly dissolution and corrosion of aluminum oxide present on the aluminum surface, caused by hydrogen fluoride generated by the reaction of an electrolyte with moisture, and improve the adhesiveness (wettability) of the aluminum surface; preventing delamination of the substrate layer from the aluminum during heat sealing; the delamination of the base material layer from the aluminum is prevented when the embossed type press molding is performed. Among the substances forming the acid-resistant coating, the treatment of applying an aqueous solution composed of three components of a phenol resin, a chromium (III) fluoride compound, and phosphoric acid to the aluminum surface, and drying and firing the coating is preferable.

The acid-resistant coating film includes a layer containing cerium oxide, phosphoric acid or a phosphate, an anionic polymer, and a crosslinking agent for crosslinking the anionic polymer, and the phosphoric acid or the phosphate may be added in an amount of about 1 to 100 parts by mass based on 100 parts by mass of the cerium oxide. The acid-resistant coating film preferably has a multilayer structure further including a layer containing a cationic polymer and a crosslinking agent for crosslinking the cationic polymer.

Further, the anionic polymer is preferably poly (meth) acrylic acid or a salt thereof, or a copolymer mainly composed of (meth) acrylic acid or a salt thereof. The crosslinking agent is preferably at least 1 selected from compounds having any functional group of an isocyanate group, a glycidyl group, a carboxyl group and an oxazoline group, and silane coupling agents.

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

The chemical conversion treatment may be performed by only 1 type of chemical conversion treatment, or may be performed by combining 2 or more types of chemical conversion treatments. These chemical conversion treatments may be carried out using 1 compound alone, or using 2 or more compounds in combination. Among the chemical conversion treatments, chromate treatment, chemical conversion treatment in which a chromium compound, a phosphoric acid compound, and an aminated phenol polymer are combined, or the like is preferable. Among the chromium compounds, a chromic acid compound is preferable.

Specific examples of the acid-resistant coating film include an acid-resistant coating film containing at least 1 of phosphate, chromate, fluoride, and triazine thiol. Also, an acid-resistant coating film containing a cerium compound is preferable. As the cerium compound, cerium oxide is preferable.

Specific examples of the acid-resistant coating include a phosphate coating, a chromate coating, a fluoride coating, and a triazine thiol compound coating. The acid-resistant coating may be 1 of these, or a combination of a plurality of these. Further, the acid-resistant coating may be formed by degreasing the surface to be chemically treated of the aluminum foil and then using a treatment liquid containing a mixture of a metal phosphate and an aqueous synthetic resin or a treatment liquid containing a mixture of a nonmetal salt of phosphate and an aqueous synthetic resin.

Among these, composition analysis of the acid-resistant coating film can be performed by, for example, time-of-flight secondary ion mass spectrometry. By the composition analysis of the acid-resistant coating film by the time-of-flight secondary ion mass spectrometry, for example, Ce can be detected⁺And Cr⁺A peak of at least one of (a).

The aluminum foil preferably has an acid-resistant coating film containing at least 1 element selected from phosphorus, chromium, and cerium on the surface thereof. Among these, it can be confirmed by X-ray photoelectron spectroscopy that at least 1 element selected from phosphorus, chromium, and cerium is contained in the acid-resistant coating film on the surface of the aluminum foil of the battery packaging material. Specifically, first, a heat-fusible resin layer, an adhesive layer, and the like laminated on an aluminum foil in a battery packaging material are physically peeled off. Next, the aluminum foil was put into an electric furnace, and organic components present on the surface of the aluminum foil were removed at about 300 ℃ for about 30 minutes. Then, it was confirmed that these elements were contained by X-ray photoelectron spectroscopy on the surface of the aluminum foil.

The amount of the acid-resistant coating film formed on the surface of the barrier layer 3 in the chemical conversion treatment is not particularly limited, and for example, in the case of performing the above-mentioned chromate treatment, it is desirable that the barrier layer 3 is formed every 1m²The content ratio of the chromium compound is about 0.5 to 50mg, preferably about 1.0 to 40mg, in terms of chromium, the content ratio of the phosphorus compound is about 0.5 to 50mg, preferably about 1.0 to 40mg, in terms of phosphorus, and the content ratio of the aminated phenol polymer is about 1.0 to 200mg, preferably about 5.0 to 150 mg.

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

The chemical conversion treatment is performed by applying a solution containing a compound for forming an acid-resistant coating film on the surface of the barrier layer by a bar coating method, a roll coating method, a gravure coating method, a dipping method, or the like, and then heating the solution so that the temperature of the barrier layer becomes about 70 to 200 ℃. Before the barrier layer is subjected to the chemical conversion treatment, the barrier layer may be subjected to 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 manner, the chemical conversion treatment of the surface of the barrier layer can be more effectively performed.

[ 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 in which the heat-fusible resin layers are heat-fused to each other at the time of assembling the battery to seal the battery element.

The resin component used for the heat-sealable resin layer 4 is not particularly limited as long as it can be heat-sealed, 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. The resin constituting the heat-fusible resin layer 4 containing a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like, and the analysis method is not particularly limited. For example, when the maleic anhydride-modified polyolefin is measured by infrared spectroscopy, the wavenumber is 1760cm^-1Neighborhood and wavenumber 1780cm^-1A peak derived from maleic anhydride was detected in the vicinity. However, when the acid modification degree is low, the peak may become small and may not be detected. In this case, the analysis can be performed by nuclear magnetic resonance spectroscopy.

Specific examples of the polyolefin include: polyethylene such as low density polyethylene, medium density polyethylene, high density polyethylene, and linear low density polyethylene; polypropylene such as homopolypropylene, a block copolymer of polypropylene (e.g., a block copolymer of propylene and ethylene), a random copolymer of polypropylene (e.g., a random copolymer of propylene and ethylene), and the like; ethylene-butene-propylene terpolymers, and the like. Among these polyolefins, polyethylene and polypropylene are preferably cited.

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

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

The acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a part of monomers constituting the cyclic polyolefin with α -unsaturated carboxylic acid or an acid anhydride thereof, or block polymerization or graft polymerization of α -unsaturated carboxylic acid or an acid anhydride thereof and the cyclic polyolefin.

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

The heat-fusible resin layer 4 may be formed of 1 resin component alone, or may be formed of a blend polymer in which 2 or more resin components are combined. The heat-fusible resin layer 4 may be formed of only 1 layer, or may be formed of 2 or more layers using the same or different resin components.

From the viewpoint of suppressing an increase in thickness of the battery packaging material and imparting high impact resistance, the heat-fusible resin layer 4 is preferably composed of unstretched polypropylene. From the same viewpoint, it is particularly preferable that the adhesive layer 5 described later is formed of a cured product of a polyurethane adhesive having a thickness of about 1 to 5 μm, and the heat-fusible resin layer 4 is formed of an unstretched polypropylene having a thickness of about 20 to 80 μm.

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

When a lubricant is present on the surface of the heat-sealable resin layer 4, the amount of the lubricant present is not particularly limited, but is preferably about 3mg/m in an environment having a temperature of 24 ℃ and a relative humidity of 60%²More preferably 4 to 15mg/m²About, preferably 5 to 14mg/m²Left and right.

The thickness of the heat-fusible resin layer 4 is not particularly limited as long as the function as a heat-fusible resin layer can be exhibited, and is preferably about 100 μm or less, more preferably about 15 to 100 μm, and still more preferably about 15 to 80 μm.

[ adhesive layer 5]

In the battery packaging material of the present invention, the adhesive layer 5 is a layer provided between the barrier layer 3 and the heat-fusible resin layer 4 as necessary to firmly adhere them.

The adhesive layer 5 is formed of a resin capable of bonding the barrier layer 3 and the heat-fusible resin layer 4. As the resin for forming the adhesive layer 5, an adhesive having the same adhesive mechanism, the same type of adhesive component, and the like as those exemplified for the adhesive layer 2 can be used. As the resin for forming the adhesive layer 5, polyolefin-based resins such as polyolefin, cyclic polyolefin, carboxylic acid-modified polyolefin, and carboxylic acid-modified cyclic polyolefin exemplified as the aforementioned heat-sealable resin layer 4 can be used. The barrier layer 3 and the heat-fusible resin layer 4 have excellent adhesionFrom the viewpoint of (2), the polyolefin is preferably a carboxylic acid-modified polyolefin, and particularly preferably a carboxylic acid-modified polypropylene. That is, the resin constituting the adhesive layer 5 may or may not contain a polyolefin skeleton, and preferably contains a polyolefin skeleton. The resin constituting the adhesive layer 5 containing a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography mass spectrometry, or the like, and the analysis method is not particularly limited. For example, when the maleic anhydride-modified polyolefin is measured by infrared spectroscopy, the wavenumber is 1760cm^-1Neighborhood and wavenumber 1780cm^-1A peak derived from maleic anhydride was detected in the vicinity. However, when the acid modification degree is low, the peak may become small and may not be detected. In this case, the analysis can be performed by nuclear magnetic resonance spectroscopy.

Further, the adhesive layer 5 may be a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, from the viewpoint of making the thickness of the battery packaging material thin and providing a battery packaging material having excellent shape stability after molding. The acid-modified polyolefin is preferably the same as the carboxylic acid-modified polyolefin or the carboxylic acid-modified cyclic polyolefin exemplified in the heat-sealable resin layer 4.

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

The epoxy curing agent is not particularly limited as long as it is a compound having at least 1 epoxy group. Examples of the epoxy curing agent include epoxy resins such as bisphenol a diglycidyl ether, modified bisphenol a diglycidyl ether, novolac glycidyl ether, glycerol polyglycidyl ether, and polyglycerol polyglycidyl ether.

The polyfunctional isocyanate-based curing agent is not particularly limited as long as it is a compound having 2 or more isocyanate groups. Specific examples of the polyfunctional isocyanate curing agent include isophorone diisocyanate (IPDI), Hexamethylene Diisocyanate (HDI), Toluene Diisocyanate (TDI), diphenylmethane diisocyanate (MDI), products obtained by polymerizing or urethanizing these isocyanates, mixtures thereof, and copolymers with other polymers.

The carbodiimide-based curing agent is not particularly limited as long as it is a compound having at least 1 carbodiimide group (-N ═ C ═ N —). The carbodiimide-based curing agent is preferably a polycarbodiimide compound having at least 2 or more carbodiimide groups.

The oxazoline-based curing agent is not particularly limited as long as it is a compound having an oxazoline skeleton. Specific examples of the oxazoline-based curing agent include Epocros series products manufactured by Nippon catalyst Co.

The curing agent may be composed of 2 or more compounds from the viewpoint of improving the adhesion between the barrier layer 3 and the heat-fusible resin layer 4 by the adhesive layer 5.

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 about 0.1 to 30% by mass, and still more preferably about 0.1 to 10% by mass.

The thickness of the adhesive layer 5 is not particularly limited as long as it can function as an adhesive layer, and when the adhesive exemplified by the adhesive layer 2 is used, it is preferably about 1 to 10 μm, more preferably about 1 to 5 μm. In addition, when the resin exemplified as the heat-fusible resin layer 4 is used, it is preferably about 2 to 50 μm, and more preferably about 10 to 40 μm. In the case of a cured product of an acid-modified polyolefin and a curing agent, it is preferably 30 μm or less, more preferably about 0.1 to 20 μm, and 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 the resin composition 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 layers having a predetermined composition can be obtained. That is, the battery packaging material of the present invention can be obtained by preparing a layer having at least the polyamide resin layer 1a, the adhesive resin layer 1b, and the polyester resin layer 1c in this order as the base layer 1, and laminating the base layer 1, the barrier layer 3, and the heat-fusible resin layer 4.

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 base material layer 1, an adhesive layer 2 provided as needed, and a barrier layer 3. Specifically, the laminate a can be formed by a dry lamination method as follows: an adhesive for forming the adhesive layer 2 is applied on the substrate layer 1 or the barrier layer 3 whose surface is subjected to chemical conversion treatment as necessary by a coating method such as a gravure coating method or a roll coating method, and after drying, the barrier layer 3 or the substrate layer 1 is laminated and the adhesive layer 2 is cured.

Next, the heat-fusible resin layer 4 is laminated on the barrier layer 3 of the laminate a. 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 may be applied to the barrier layer 3 of the laminate a by a method such as a gravure coating method or a roll coating method. In the case where the adhesive layer 5 is provided between the barrier layer 3 and the heat-fusible resin layer 4, examples thereof include: (1) a method of laminating the adhesive layer 5 and the heat-fusible resin layer 4 on the barrier layer 3 of the laminate a by coextrusion (coextrusion lamination method); (2) a method of forming a laminate in which the adhesive layer 5 and the heat-fusible resin layer 4 are laminated, and laminating the laminate on the barrier layer 3 of the laminate A by a heat lamination method; (3) a method in which an adhesive for forming the adhesive layer 5 is applied to the barrier layer 3 of the laminate a by an extrusion method or a solution, dried at a high temperature, and then laminated by a sintering method or the like, and a heat-fusible resin layer 4 previously formed into a sheet shape is laminated on the adhesive layer 5 by a heat lamination method; (4) a method (interlayer lamination method) in which the laminate a and the heat-fusible resin layer 4 are bonded to each other by the adhesive layer 5 while the molten adhesive layer 5 is poured between the barrier layer 3 of the laminate a and the heat-fusible resin layer 4 formed in a sheet shape in advance.

In order to enhance the adhesiveness between the adhesive layer 2 and the adhesive layer 5 provided as needed, a laminate comprising the base material layer 1, the adhesive layer 2 provided as needed, the barrier layer 3 whose surface has been subjected to chemical conversion treatment as needed, and the heat-fusible resin layer 4 can be further subjected to heat treatment such as a heat roller contact type, a hot air type, a near infrared type, or a far infrared type. Examples of the conditions for such heat treatment include heating at 150 to 250 ℃ for 1 to 5 minutes.

In the battery packaging material of the present invention, each layer constituting the laminate may be subjected to surface activation treatment such as corona treatment, sand blasting, oxidation treatment, ozone treatment, or the like as necessary, in order to improve or stabilize film formability, lamination processing, 2-pass processing (bag making, embossing) suitability of the final product, or the like.

4. Use of packaging material for battery

The battery packaging material of the present invention is used for a package for sealing and housing battery elements such as a positive electrode, a negative electrode, and an electrolyte. That is, a battery can be formed by housing a battery element having 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, the battery packaging material of the present invention is used to cover a battery element having at least a positive electrode, a negative electrode, and an electrolyte so that flange portions (regions where heat-fusible resin layers are in contact with each other) can be formed at the peripheral edge of the battery element in a state where metal terminals connected to the positive electrode and the negative electrode are protruded outward, and the heat-fusible resin layers of the flange portions are heat-sealed and sealed with each other, thereby providing a battery using the battery packaging material. When a battery element is housed in a package formed of the battery packaging material of the present invention, the package is formed such that the heat-fusible resin portion of the battery packaging material of the present invention is on the inside (the surface in contact with the battery element).

The battery packaging material of the present invention can be used for both primary batteries and secondary batteries, and 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, and examples thereof include a lithium ion battery, a lithium ion polymer battery, a lead storage battery, a nickel-hydrogen storage battery, a nickel-cadmium storage battery, a nickel-iron storage battery, a nickel-zinc storage battery, a silver oxide-zinc storage battery, a metal air battery, a polyvalent cation battery, a capacitor (condenser), and a capacitor (capacitor). Among these secondary batteries, lithium ion batteries and lithium ion polymer batteries are preferable examples of the battery packaging material of the present invention.

Examples

The present invention will be described in detail below by way of examples and comparative examples. However, the present invention is not limited to the examples.

(examples 1 to 8 and comparative examples 1 to 10)

< production of packaging Material for Battery >

The base material layer, the barrier layer, the adhesive layer, and the heat-fusible resin layer were laminated to have a laminated structure shown in table 1, thereby producing a battery packaging material. In the laminate structure shown in Table 1, the numerical values indicate the thickness (μm) of each layer, and for example, "PET 5" indicates polyethylene terephthalate having a thickness of 5 μm. In table 1, PET means polyethylene terephthalate, AD means an adhesive resin layer, ONY means stretched nylon, DL means an adhesive layer or an adhesive layer formed by a dry lamination method in the lamination step, ALM means aluminum foil, PP means polypropylene, 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 a base material layer by a dry lamination method. Specifically, a two-pack type polyurethane adhesive (a polyol compound and an aromatic isocyanate compound) was applied to one surface of a barrier layer having an acid-resistant coating film formed on the surface thereof, and an adhesive layer (thickness: 3 μm) was formed on an aluminum foil. Next, the adhesive layer on the barrier layer and the polyamide resin layer side of the base layer are laminated by a dry lamination method, and then subjected to a curing treatment, thereby producing a laminate of the base layer/adhesive layer/barrier layer.

Next, in examples 1, 3, 5, and 7 and comparative examples 1, 3, 5, 7, and 9, maleic anhydride-modified polypropylene as an adhesive layer and polypropylene as a heat-fusible resin layer were melt-coextruded on the barrier layer (acid-resistant coating film) of each of the obtained laminates, whereby the adhesive layer and the heat-fusible resin layer were laminated on the surface of the barrier layer, and a battery packaging material was obtained in which the base layer/adhesive layer/barrier layer/adhesive layer/heat-fusible resin layer were laminated in this order.

On the other hand, in examples 2, 4, 6 and 8 and comparative examples 2, 4, 6, 8 and 10, a two-liquid polyurethane adhesive (a polyol compound and an aromatic isocyanate compound) was applied to the barrier layer (acid-resistant coating film) of each of the obtained substrate layer/adhesive layer/barrier layer laminates, and an adhesive layer (thickness 3 μm) was formed on the aluminum foil. Next, the adhesive layer on the barrier layer and the non-stretched polypropylene were laminated by a dry lamination method, and then subjected to a curing treatment, thereby obtaining a battery packaging material in which a base material layer/adhesive layer/barrier layer/adhesive layer/heat-fusible resin layer were laminated in this order.

< evaluation of electrolyte resistance >

The obtained packaging material for each battery was cut to prepare a test piece of 100mm × 100mm, which was used as a test sample. 0.1g of an electrolyte (prepared by adding 1mol of lithium hexafluorophosphate to 1:1:1 (volume ratio) of ethylene carbonate, diethyl carbonate and dimethyl carbonate) was dropped onto the surface of the test sample on the base layer side in an atmosphere at room temperature (25 ℃) and left as it was for 1 hour. After that, the electrolyte solution was wiped off with a waste cloth, and whether whitening occurred on the surface of the base material layer was observed visually. The case where whitening did not occur was determined as a, and the case where whitening occurred was determined as C. The results are shown in Table 1.

< number of laminations >

In the production of the above-mentioned battery packaging material, the number of times each layer was laminated is shown in table 1. In examples 1, 3, 5, and 7 and comparative examples 1, 3, 5, 7, and 9, the following 2 lamination steps were performed: a laminating step of laminating the base layer and the barrier layer by a dry lamination method, and a laminating step of laminating the adhesive layer and the heat-fusible resin layer by a melt coextrusion method to the barrier layer. In examples 2, 4, 6, and 8 and comparative examples 2, 4, 6, and 8, the following 2 lamination steps were performed: a laminating step by a dry laminating method between the base layer and the barrier layer, and a laminating step by a dry laminating method between the barrier layer and the non-stretched polypropylene film.

< determination of impact Strength (J) >

The impact strength (J) of each of the battery packaging materials obtained above was measured from the base layer side according to the specification of ASTM D3420. As the measuring apparatus, a film impact tester manufactured by Toyo Seiki Seisaku-Sho was used, and a hemispherical impact head having a smooth surface with a radius of 12.7mm was used. In the measurement of the impact strength, a test piece cut to a diameter of 100mm was used. The sample was held between 2 plates with a circular opening of 89. + -. 0.5mm diameter in the center. The impact strength of each sample was determined by taking the average value of 3 measurements of each sample. The measurement was carried out at a temperature of 23. + -. 2 ℃ and a relative humidity of 50. + -. 5%. The results are shown in table 1.

< measurement of layer thickness of laminate >

The total thickness of the laminate constituting each battery packaging material obtained above was measured using a micrometer manufactured by Mitutoyo. The results are shown in Table 1. In the examples and comparative examples, the values (J/μm) obtained by dividing the impact strength measured by the above method by the thickness (μm) of each laminate are shown in table 1, because the laminates have different thicknesses.

[ Table 1]

From the results shown in table 1, it can be seen that: the battery packaging materials of examples 1 to 8 have high impact resistance and electrolyte solution resistance, and the substrate layer of the battery packaging materials of examples 1 to 8 has a polyamide resin layer, an adhesive resin layer, and a polyester resin layer in this order from the barrier layer side, and the thickness of the polyester resin layer is 6 μm or less, and the value obtained by dividing the impact strength (J) of the laminate measured from the substrate layer side by the thickness (μm) of the laminate is 0.015J/μm or more, based on the specification of ASTM D3420.

In comparative examples 6 and 8 having relatively large thicknesses, the impact strength also became large, but in examples 3, 4, 7, and 8 having thicknesses of the same degree, the impact strength was larger than in comparative examples 6 and 8.

< measurement of hardness of each layer of example 4 >

As an apparatus, a nanoindenter ("tribo indenter ti 950" manufactured by hystron corporation) was used as an indenter of the nanoindenter, a Berkovich indenter (triangular pyramid) was used, first, the indenter was brought into contact with the surface of the adhesive layer (the surface on which the adhesive layer was exposed, in the direction perpendicular to the lamination direction of the layers) of the battery packaging material in an environment of a relative humidity of 50% and 23 ℃_max(μ N) and projected area of contact A (μm) at maximum depth²) By the use of P_maxThe indentation hardness (MPa) was calculated. The measurement positions were changed, 5 positions were measured, and the average value was used. The hardness of the adhesive resin layer was measured in the same manner as in the adhesive layer, except that the load was changed to 10 μ N or more. The hardness of each of the polyethylene terephthalate film and the stretched nylon film as the base material layer was measured in the same manner except that the load was set to 100 μ N under the above measurement conditions. The respective hardnesses are shown in table 2. The surface of the press-fit indenter is a portion where a cross section of a measurement object (an adhesive layer or the like) is exposed, which is obtained by cutting in the thickness direction so as to pass through the center portion of the battery packaging material. The cutting was performed using a commercially available rotary microtome or the like.

< evaluation of moldability >

The battery packaging material of example 4 was cut into a rectangular shape having a length (x direction) of 90mm × a width (y direction) of 150mm, and used as a test sample. For this sample, 10 samples were cold-rolled (1-stage molding) using a rectangular molding die (female die, nominal value of Rz of JIS B0659-1: 2002 attached document 1 (reference) comparative surface roughness standard sheet specified in table 2, with a 31.6mm (x direction) × 54.5mm (y direction) caliber (3.2 μm. corner r2.0mm, ridge line r1.0mm), and a molding die corresponding thereto (male die, nominal value of Rz of JIS B0659-1: 2002 attached document 1 (reference) comparative surface roughness standard sheet specified in table 2, with a molding depth of 0.5mm changed in units of 0.5mm from the molding depth of 0.5mm, and a pressing pressure (surface pressure) of 0.25MPa, respectively. At this time, the test sample was placed on a female mold and molded so that the side of the heat-fusible resin layer was on the male mold side. Further, the clearance between the male mold and the female mold was 0.3 mm. The cold-rolled sample was irradiated with light in a dark room using a pen torch, and whether or not pinholes or cracks were generated in the aluminum foil was confirmed by light transmission. The deepest molding depth at which no pinholes or cracks were generated in the aluminum foil was Amm for all 10 samples, and the number of samples at which pinholes or the like were generated in the shallowest molding depth at which pinholes or the like were generated in the aluminum foil was B, and the value calculated by the following equation was used as the limit molding depth of the battery packaging material. The results are shown in Table 2.

Ultimate forming depth of Amm + (0.5 mm/10) × (10-B)

[ Table 2]

Description of the symbols

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

1. A packaging material for a battery, characterized in that:

comprising a laminate comprising at least a base material layer, a barrier layer and a heat-sealable resin layer in this order,

the base material layer at least comprises a polyamide resin layer, an adhesive resin layer and a polyester resin layer in sequence from the side of the barrier layer,

the thickness of the polyester resin layer is 6 μm or less,

the laminate has a value of 0.015J/μm or more obtained by dividing the impact strength of the laminate measured from the base material layer side by the thickness of the laminate, in accordance with the specification of ASTM D3420.

2. The packaging material for batteries according to claim 1, wherein:

an adhesive layer is provided between the base material layer and the barrier layer,

the adhesive resin layer and the adhesive layer each have a hardness of 50MPa or less as measured by a nanoindentation method.

3. The packaging material for batteries according to claim 1 or 2, wherein:

the adhesive resin layer is formed of at least 1 selected from the group consisting of an acid-modified polyolefin-based resin, an acid-modified styrene-based elastomer resin, and an acid-modified polyester-based elastomer resin.

4. The packaging material for a battery according to any one of claims 1 to 3, wherein:

the heat-fusible resin layer is composed of unstretched polypropylene.

5. The packaging material for a battery according to any one of claims 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.

6. The packaging material for a battery according to any one of claims 1 to 5, wherein:

the thickness of the laminate is 180 μm or less.

7. The packaging material for a battery according to any one of claims 1 to 6, wherein:

the polyamide resin layer is made of nylon.

8. The packaging material for a battery according to any one of claims 1 to 7, wherein:

the polyester resin layer is composed of polyethylene terephthalate.

9. A battery, characterized by:

a battery element having 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.