CN108431987B

CN108431987B - Battery packaging material, method for producing same, and battery

Info

Publication number: CN108431987B
Application number: CN201780006100.7A
Authority: CN
Inventors: 津森薰; 山下力也; 山下孝典
Original assignee: Dai Nippon Printing Co Ltd
Current assignee: Dai Nippon Printing Co Ltd
Priority date: 2016-10-05
Filing date: 2017-10-05
Publication date: 2020-09-01
Anticipated expiration: 2037-10-05
Also published as: JPWO2018066671A1; CN108431987A; WO2018066671A1; JP7238403B2

Abstract

The invention provides a packaging material for a battery, which can ensure the safety even under the condition that the pressure or the temperature in the battery is continuously increased. The battery packaging material is composed of a laminate having at least a base material layer, a barrier layer, an adhesive layer, and a heat-sealable resin layer in this order, wherein in thermomechanical analysis for measuring the displacement amount of a probe, the probe is provided on the surface of the adhesive layer in the cross section of the laminate, and the probe is heated from 40 ℃ to 220 ℃ under conditions that the set value of the deflection of the probe at the start of measurement is-4V and the temperature rise rate is 5 ℃/min, and the temperature at which the position of the probe is lower than the initial value is 130 ℃ or lower.

Description

Battery packaging material, method for producing same, and battery

Technical Field

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

Background

Various types of batteries have been developed, and in all of the batteries, a packaging material is an indispensable member for sealing battery elements such as electrodes and electrolytes. Conventionally, a metal packaging material has been used as a battery package in many cases.

On the other hand, in recent years, with the increase in performance of electric vehicles, hybrid electric vehicles, computers, cameras, cellular phones, and the like, batteries are required to have various shapes, and thinning and weight reduction are required. However, the metal-made battery packaging materials that have been used in many cases in the prior art have drawbacks that it is difficult to adapt to the diversification of shapes and that weight reduction is also 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 base material layer, an adhesive layer, a barrier layer, and a heat-sealable resin layer are sequentially laminated has been proposed (for example, see patent document 1). The film-like battery packaging material is formed by: the heat-fusible resin layers are opposed to each other, and the peripheral edge portions are heat-fused to seal the battery element.

On the other hand, in the battery, the temperature in the battery is continuously increased by charging with overvoltage or discharging at the time of excessive current, and the battery reaction may be caused to run away.

Therefore, in the battery packaging material, in order to ensure safety when the pressure or temperature in the battery continues to rise, the following design is required: the battery element is kept in a sealed state so as not to crack until a predetermined temperature is reached, thereby suppressing ignition and the like due to rapid ejection of a combustible gas, and thereafter, the battery element is smoothly opened to gradually release the gas in the battery packaging material.

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

The purpose of the present invention is to provide a battery packaging material that can suppress excessive swelling, ignition, and the like of the battery packaging material.

Means for solving the problems

The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, have found that a battery packaging material comprising a laminate comprising at least a base material layer, a barrier layer, an adhesive layer and a heat-sealable resin layer in this order, in the thermomechanical analysis for measuring the displacement of the probe, the probe is arranged on the surface of the adhesive layer of the cross section of the battery packaging material, when the probe is heated from 40 ℃ to 220 ℃ under the conditions that the set value of the deflection (deflection) of the probe at the start of measurement is-4V and the temperature rise rate is 5 ℃/min, the temperature at which the position of the probe is lower than the initial value is 130 ℃ or lower, the packaging material for a battery can maintain a state in which a battery element is sealed until the increase in pressure and temperature within the battery reaches a certain level, and can lead to smooth unsealing at the time when the state in which the pressure and temperature in the battery are continuously raised is reached.

The present inventors have also found that a battery packaging material comprising a laminate having at least a base layer, a barrier layer, an adhesive layer, and a heat-sealable resin layer in this order can be opened smoothly even when the probe is placed on the surface of the adhesive layer on the cross section of the battery packaging material in a thermomechanical analysis for measuring the displacement of the probe, and the probe is heated from 40 ℃ to 220 ℃ under conditions in which the probe deflection is set to-4V at the start of measurement and the temperature rise rate is 5 ℃/min, the temperature at which the position of the probe reaches the highest point is 100 ℃ or less, and the battery packaging material can maintain the sealed state of the battery element until the pressure and temperature rise in the battery reach a certain level, and can be opened smoothly at the time when the pressure and temperature in the battery continue to rise.

The present invention has been completed based on these findings and further research and study has been conducted. That is, the present invention provides the following embodiments.

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

in the thermomechanical analysis for measuring the displacement of a probe, the probe is arranged on the surface of the bonding layer of the cross section of the laminated body, and when the probe is heated from 40 ℃ to 220 ℃ under the conditions that the set value of the deflection of the probe at the start of measurement is-4V and the heating rate is 5 ℃/min, the temperature at which the position of the probe is lower than the initial value is 130 ℃ or lower.

The packaging material for a battery according to item 2, which comprises a laminate comprising at least a base material layer, a barrier layer, an adhesive layer and a heat-sealable resin layer in this order,

in the thermomechanical analysis for measuring the displacement amount of a probe, the probe is arranged on the surface of the bonding layer of the cross section of the laminated body, and when the probe is heated from 40 ℃ to 220 ℃ under the conditions that the set value of the deflection of the probe at the start of measurement is-4V and the heating rate is 5 ℃/min, the temperature at which the position of the probe reaches the highest point is 100 ℃ or lower.

The battery packaging material according to item 1 or 2, wherein a portion of the battery packaging material where the heat-fusible resin layers are heat-fused to each other has a sealing strength of 1/8 or less at a temperature of 120 ℃ or less than a sealing strength at a temperature of 25 ℃.

The battery packaging material according to any one of claims 1 to 3, wherein a sealing strength of a portion of the battery packaging material obtained by thermally welding the thermally-weldable resin layers to each other at 120 ℃ is 20N/15mm or less.

The battery packaging material of any one of claims 1 to 4, wherein the base material layer has at least one of a polyester film layer and a polyamide film layer.

The battery packaging material according to any one of claims 1 to 4, wherein the base material layer has at least a polyester film layer and a polyamide film layer.

The battery packaging material of item 6, wherein a ratio of the thickness of the polyester film layer to the thickness of the polyamide film layer is in a range of 1: 1 to 1: 5.

The battery packaging material according to claim 6 or 7, wherein the substrate layer has the polyamide film layer and the polyester film layer in this order from the barrier layer side.

The battery packaging material according to any one of claims 6 to 8, wherein a layer containing at least one of polyester and polyolefin is provided between the polyester film layer and the polyamide film layer.

The battery packaging material according to any one of claims 1 to 9, wherein the resin constituting the adhesive layer contains a polyolefin skeleton.

The battery packaging material of any one of claims 1 to 9, wherein the adhesive layer contains an acid-modified polyolefin.

The battery packaging material according to claim 11, wherein the acid-modified polyolefin of the adhesive layer is maleic anhydride-modified polypropylene, and the heat-fusible resin layer contains polypropylene.

The battery packaging material of any one of items 1 to 12, wherein the adhesive layer is a cured product of a resin composition containing at least 1 selected from a compound having an isocyanate group, a compound having an oxazoline group, and a compound having an epoxy group.

The battery packaging material of any one of items 1 to 12, wherein the adhesive layer is a cured product of a resin composition containing a curing agent having at least 1 selected from an oxygen atom, a heterocycle, a C ═ N bond, and a C — O — C bond.

The battery packaging material of any one of claims 1 to 12, wherein the adhesive layer contains at least 1 selected from a polyurethane resin, an ester resin, and an epoxy resin.

The battery packaging material of any one of claims 1 to 15, wherein the adhesive layer has a thickness of 5 μm or less.

The battery packaging material according to any one of claims 1 to 16, wherein the barrier layer has an acid-resistant coating on a surface thereof, and when the acid-resistant coating is analyzed by a time-of-flight secondary ion mass spectrometry, a detection result derived from Ce is detected₂PO₄ ⁺、CePO₄ ^-、CrPO₂ ⁺And CrPO₄ ^-Peak of at least 1 species.

The battery packaging material of any one of claims 1 to 16, wherein an acid-resistant coating film containing at least 1 selected from the group consisting of a phosphorus compound, a chromium compound, a fluoride compound and a triazine thiol compound is provided on the surface of the barrier layer.

The battery packaging material of any one of claims 1 to 16, wherein an acid-resistant coating containing a cerium compound is provided on a surface of the barrier layer.

The battery according to item 20, 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 19.

The method of producing a packaging material for a battery according to item 21, which comprises a step of sequentially laminating at least a base material layer, a barrier layer, an adhesive layer and a heat-fusible resin layer to obtain a laminate,

as the adhesive layer, a material satisfying the following conditions is used: in the thermomechanical analysis for measuring the displacement of a probe, the probe is arranged on the surface of the bonding layer of the cross section of the laminated body, and when the probe is heated from 40 ℃ to 220 ℃ under the conditions that the set value of the deflection of the probe at the start of measurement is-4V and the heating rate is 5 ℃/min, the temperature at which the position of the probe is lower than the initial value is 130 ℃ or lower.

The method of producing a packaging material for a battery according to item 22, which comprises a step of sequentially laminating at least a base material layer, a barrier layer, an adhesive layer and a heat-fusible resin layer to obtain a laminate,

as the adhesive layer, a material satisfying the following conditions is used: in the thermomechanical analysis for measuring the displacement amount of a probe, the probe is arranged on the surface of the bonding layer of the cross section of the laminated body, and when the probe is heated from 40 ℃ to 220 ℃ under the conditions that the set value of the deflection of the probe at the start of measurement is-4V and the heating rate is 5 ℃/min, the temperature at which the position of the probe reaches the highest point is 100 ℃ or lower.

Effects of the invention

The first battery packaging material of the present invention is characterized by comprising a laminate comprising at least a base material layer, a barrier layer, an adhesive layer and a heat-sealable resin layer in this order, wherein in a thermomechanical analysis for measuring the displacement amount of a probe, the probe is provided on the surface of the adhesive layer in the cross section of the battery packaging material, and when the probe is heated from 40 ℃ to 220 ℃ under the conditions that the set value of the deflection of the probe at the start of measurement is-4V and the temperature rise rate is 5 ℃/min, the temperature at which the position of the probe is lower than the initial value is 130 ℃ or lower. The second battery packaging material of the present invention is characterized by comprising a laminate comprising at least a base material layer, a barrier layer, an adhesive layer, and a heat-sealable resin layer in this order, wherein in the thermomechanical analysis for measuring the displacement amount of the probe, the probe is provided on the surface of the adhesive layer in the cross section of the battery packaging material, and the temperature at which the position of the probe reaches the highest point is 100 ℃ or less when the probe is heated from 40 ℃ to 220 ℃ under the conditions that the set value of the deflection of the probe at the start of measurement is-4V and the temperature increase rate is 5 ℃/min. According to the battery packaging material of the present invention, even when the pressure or temperature in the battery continues to rise, the battery packaging material can be smoothly opened, excessive expansion or ignition of the battery packaging material can be suppressed, and safety can be ensured.

Drawings

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

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

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

Fig. 4 is a diagram showing an example of a cross-sectional structure of a battery packaging material, and is a diagram showing a position where a probe is provided (an adhesive layer surface in a cross section of the battery packaging material) in a thermomechanical analysis for measuring a displacement amount of the probe.

Fig. 5 is a conceptual diagram illustrating a change in the position of the probe in the thermomechanical analysis for measuring the displacement amount of the probe.

Fig. 6 is a graph showing the relationship between the heating temperature and the displacement of the probe position when the probe was placed on the adhesive layer surface of the cross section of the battery packaging material obtained in example 1 and heated from 40 ℃ to a predetermined temperature.

Fig. 7 is a graph showing the relationship between the heating temperature and the displacement of the probe position when the probe was placed on the adhesive layer surface of the cross section of the battery packaging material obtained in example 2 and heated from 40 ℃ to a predetermined temperature.

Fig. 8 is a graph showing the relationship between the heating temperature and the displacement of the probe position when the probe was placed on the adhesive layer surface of the cross section of the battery packaging material obtained in example 3 and heated from 40 ℃ to a predetermined temperature.

Fig. 9 is a graph showing the relationship between the heating temperature and the displacement of the probe position when the probe was placed on the adhesive layer surface of the cross section of the battery packaging material obtained in example 4 and heated from 40 ℃ to a predetermined temperature.

Fig. 10 is a graph showing the relationship between the heating temperature and the displacement of the probe position when the probe was placed on the adhesive layer surface of the cross section of the battery packaging material obtained in comparative example 1 and heated from 40 ℃ to a predetermined temperature.

Fig. 11 is a graph showing the relationship between the heating temperature and the displacement of the probe position when the probe was placed on the adhesive layer surface of the cross section of the battery packaging material obtained in comparative example 2 and heated from 40 ℃ to a predetermined temperature.

Fig. 12 is a schematic diagram for explaining a method of evaluating the sealing property of the battery packaging material in the example.

Fig. 13 is a schematic diagram for explaining a method of evaluating the sealing property of the battery packaging material in the example.

Fig. 14 is a schematic diagram for explaining a method of measuring the seal strength of the battery packaging material in the example.

Fig. 15 is a schematic diagram for explaining a method of measuring the sealing strength of the battery packaging material in the example.

Fig. 16 is a schematic cross-sectional view of one surface (left end heat-sealed, right side omitted) of 2 sheets of the battery packaging material of the present invention in a state (a) in which a sealed space is formed by heat-sealing, a state (B) in which peeling is formed after temperature rise, and a state (C) in which the battery packaging material is opened.

Fig. 17 is a schematic cross-sectional view of one surface (left end heat-sealed, right side omitted) of 2 sheets of the battery packaging material of the present invention in a state (a) in which a sealed space is formed by heat-sealing, a state (B) in which peeling is formed after temperature rise, and a state (C) in which the battery packaging material is opened.

Fig. 18 is a schematic cross-sectional view of one surface (left end heat-sealed, right side omitted) of 2 sheets of the battery packaging material of the present invention in a state (a) in which a sealed space is formed by heat-sealing, a state (B) in which peeling is formed after temperature rise, and a state (C) in which the battery packaging material is opened.

Fig. 19 is a schematic perspective view showing a position (at 5) where a probe is provided in the thermomechanical analysis for measuring the displacement amount of the probe.

Detailed Description

The first battery packaging material of the present invention is characterized by comprising a laminate having at least a base material layer, a barrier layer, an adhesive layer, and a heat-sealable resin layer in this order, wherein in thermomechanical analysis for measuring the displacement amount of a probe, the probe is provided on the surface of the adhesive layer in the cross section of the laminate, and when the probe is heated from 40 ℃ to 220 ℃ under conditions in which the set value of the deflection of the probe at the start of measurement is-4V and the temperature rise rate is 5 ℃/min, the temperature at which the position of the probe is lower than the initial value is 130 ℃ or lower.

The second battery packaging material of the present invention is characterized by comprising a laminate having at least a base material layer, a barrier layer, an adhesive layer, and a heat-sealable resin layer in this order, wherein in the thermomechanical analysis for measuring the displacement amount of the probe, the probe is provided on the surface of the adhesive layer in the cross section of the laminate, and the temperature at which the position of the probe reaches the highest point is 100 ℃ or less when the probe is heated from 40 ℃ to 220 ℃ under the conditions that the set value of the deflection of the probe at the start of measurement is-4V and the temperature increase rate is 5 ℃/min.

In the battery packaging material of the present invention, by adopting these specific configurations, the sealed state of the battery element can be maintained until the increase in the pressure and temperature in the battery reaches a certain level, and the opening can be smoothly guided when the state in which the pressure and temperature in the battery continue to increase is reached. More specifically, after the increase in pressure and temperature within the battery reaches a certain level, the combustible gas generated within the battery is released to the outside, thereby enabling the internal pressure to be stably reduced. The release of the electrolyte to the outside of the battery cell can be suppressed by the decrease in the internal pressure inside the battery. In addition, by flowing air into the battery while releasing gas, the concentration of the combustible gas generated in the battery becomes low, and ignition of the battery can be suppressed. Further, the electrolyte inside the battery is easily dried by the inflow of air, and thus ignition of the battery can be suppressed. In particular, when the battery reaches a high temperature, the separator inside the battery is likely to contract, and therefore the internal pressure increases, the battery deforms, and the risk of ignition due to a short circuit increases.

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" with respect to the numerical ranges. For example, the term of 2 to 15mm means 2mm to 15 mm.

1. Laminate structure of battery packaging material

For example, as shown in fig. 1, a battery packaging material 10 of the present invention is composed of a laminate having a base material layer 1, a barrier layer 3, an adhesive layer 4, and a heat-fusible resin layer 5 in this order. In the battery packaging material of the present invention, the base material layer 1 is the outermost layer side, and the heat-sealable resin layer 5 is the innermost layer side. That is, at the time of battery assembly, the heat-fusible resin layers 5 located at the peripheral edge of the battery element are heat-fused to each other to seal the battery element, whereby the battery element is sealed.

The battery packaging material of the present invention may have an adhesive layer 2 between the base material layer 1 and the barrier layer 3 as necessary to improve the adhesiveness therebetween, as shown in fig. 2, for example. As shown in fig. 3, a surface coating layer 6 or the like may be provided on the outer side of the base material layer 1 (the side opposite to the heat-fusible resin layer 5) as necessary.

The thickness of the laminate constituting the battery packaging material of the present invention is not particularly limited, and from the viewpoint of minimizing the thickness of the laminate and exerting high insulation properties, it is preferably about 160 μm or less, more preferably about 35 to 155 μm, and still more preferably about 45 to 120 μm. The laminate constituting the battery packaging material of the present invention can exhibit excellent insulating properties even when the thickness thereof is as thin as 160 μm or less, for example. Therefore, the battery packaging material of the present invention contributes to an improvement in the energy density of the battery.

2. Each layer forming the packaging material for batteries

[ base Material layer 1]

In the battery packaging material of the present invention, the base material layer 1 is a layer located on the outermost layer side. The material forming the base layer 1 is not particularly limited as long as it has insulation properties.

Examples of the material forming the base layer 1 include resins such as polyester, polyamide, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, phenol resin, polyetherimide, polyimide, and a mixture or copolymer thereof. The substrate layer 1 may be formed of a resin film or may be formed by coating a resin.

The base layer 1 may have a single-layer structure formed of these resins, or may have a multilayer structure in order to improve pinhole resistance and insulation properties when the battery package is formed. Specific examples of the multilayer structure include a multilayer structure in which a polyester film and a nylon film are laminated, a multilayer structure in which a plurality of nylon films are laminated, and a multilayer structure in which a plurality of polyester films are laminated. When the base layer 1 has a multilayer structure, a laminate of a biaxially stretched nylon film and a biaxially stretched polyester film, a laminate obtained by laminating a plurality of biaxially stretched nylon films, and a laminate obtained by laminating a plurality of biaxially stretched polyester films are preferable. For example, when the base layer 1 is formed of a 2-layer resin film, a structure in which a polyester resin and a polyester resin are laminated, a structure in which a polyamide resin and a polyamide resin are laminated, or a structure in which a polyester resin and a polyamide resin are laminated is preferable, and a structure in which polyethylene terephthalate and polyethylene terephthalate are laminated, a structure in which nylon and nylon are laminated, or a structure in which polyethylene terephthalate and nylon are laminated is more preferable. When the substrate layer 1 has a multilayer structure, the thickness of each layer is preferably 3 to 25 μm.

When the base layer 1 has a multilayer structure, the layers may be bonded via an adhesive, or may be directly laminated without an adhesive. When the bonding is not performed by an adhesive, for example, a method of bonding in a hot-melt state such as a coextrusion method, a sandwich method, or a heat lamination method can be mentioned. In the case of bonding via an adhesive, the adhesive used may be a two-component curing adhesive or a one-component curing adhesive. The adhesive is not particularly limited, and may be any type such as a chemical reaction type, a solvent volatilization type, a hot melt type, a hot press type, an electron beam curing type, or an ultraviolet curing type. Specific examples of the adhesive include those similar to the adhesives exemplified for the adhesive layer 2. The thickness of the adhesive can be the same as that of the adhesive layer 2.

The base material layer 1 preferably has at least one of a polyester film layer and a polyamide film layer, and more preferably at least a polyester film layer and a polyamide film layer.

Specific examples of the polyester constituting the polyester film layer include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, polycarbonate, a copolyester mainly composed of ethylene terephthalate and a copolyester mainly composed of butylene terephthalate. Specific examples of the copolyester mainly composed of ethylene terephthalate as a repeating unit include a copolyester mainly composed of ethylene terephthalate as a repeating unit and polymerized with ethylene isophthalate (hereinafter, simply 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), and polyethylene glycol (terephthalate/decanedicarboxylate). Specific examples of the copolyester mainly containing butylene terephthalate as a repeating unit include a copolyester mainly containing butylene terephthalate as a repeating unit and polymerized with butylene isophthalate (hereinafter, simply referred to as "polybutylene terephthalate/isophthalate"), polybutylene terephthalate (terephthalate/adipate), polybutylene terephthalate (terephthalate/sebacic acid), polybutylene terephthalate (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 advantages such as excellent electrolyte resistance and less tendency to cause whitening on the electrolyte adhesion, and is suitable for use as a material for forming the base material layer 1.

The polyester film layer is preferably formed of a biaxially stretched polyester film, and particularly preferably a biaxially stretched polyethylene terephthalate film.

The thickness of the polyester film layer is not particularly limited, but is preferably about 20 μm or less, more preferably about 1 to 15 μm, and still more preferably about 3 to 12 μm, from the viewpoint of making the battery packaging material thinner and exhibiting excellent moldability.

In addition, as the polyamide constituting the polyamide film layer, specifically, there can be mentioned: 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 copolyamides 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, and aromatic polyamides such as polymetaxylylene adipamide (MXD 6); alicyclic polyamides such as poly (aminomethyl) cyclohexyl adipamide (PACM 6); and polyamides obtained by copolymerizing lactam components or isocyanate components such as 4, 4' -diphenylmethane-diisocyanate, and polyester amide copolymers or polyether ester amide copolymers which are copolymers of a copolymerized polyamide and a polyester or polyalkylene ether glycol; copolymers thereof, and the like. These polyamides may be used alone in 1 kind, or 2 or more kinds may be used in combination. The stretched polyamide film is excellent in stretchability, can prevent whitening due to cracking of the resin of the base layer 1 during molding, and is suitable for use as a material for forming the base layer 1.

The polyamide film layer is preferably formed of a biaxially stretched polyamide film, and particularly preferably a biaxially stretched nylon film.

The thickness of the polyamide film layer is not particularly limited, but is preferably about 30 μm or less, more preferably about 1 to 25 μm, and still more preferably about 10 to 25 μm, from the viewpoint of making the battery packaging material thinner and exhibiting excellent moldability.

From the viewpoint of further improving moldability, in the base material layer 1, the ratio of the thickness of the polyester film layer to the thickness of the polyamide film layer (the thickness of the polyester film layer: the thickness of the polyamide film layer) is preferably in the range of 1: 1 to 1: 5, and more preferably in the range of 1: 1.2 to 1: 4. When the thickness ratio is within such a range, the balance of stress at the time of molding the battery packaging material can be easily obtained, and the battery packaging material can be appropriately thinned.

In the base material layer 1, the order of lamination of the polyester film layer and the polyamide film layer is not particularly limited, and the polyester resin is less likely to be discolored when, for example, an electrolytic solution adheres to the surface, and therefore, from the viewpoint of improving the electrolytic solution resistance of the battery packaging material, it is preferable to have the polyamide film layer and the polyester film layer from the barrier layer 3 side described later.

Between the polyester film layer and the polyamide film layer, there may be a layer containing at least one of polyester and polyolefin. The polyolefin is preferably a resin composition containing a modified thermoplastic resin 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 unsaturated carboxylic acid, 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-alpha-olefin copolymers; homopolypropylene, block polypropylene or random polypropylene; propylene- α -olefin copolymers; copolymers obtained by copolymerizing polar molecules such as acrylic acid and methacrylic acid with the above-mentioned materials; crosslinked polyolefin polymers, and the like. The polyolefin-based 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, 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 unsaturated carboxylic acid esters 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 the following reaction: 0.2 to 100 parts by mass of the unsaturated carboxylic acid derivative component is heated and reacted with 100 parts by mass of the thermoplastic resin as a matrix in the presence of a radical initiator.

The reaction temperature is preferably about 50 to 250 ℃, and more preferably about 60 to 200 ℃. The reaction time is also limited by the production method, and when the melt grafting reaction is performed by a twin screw extruder, the residence time of the extruder is preferably about 2 to 30 minutes, and more preferably about 5 to 10 minutes. The modification reaction may be carried out under any conditions of normal pressure and 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 melt grafting reaction using the twin-screw extruder described above, alkyl peroxides, peroxyketals, and peroxyesters are preferable, and di-tert-butyl peroxide, 2, 5-dimethyl-2, 5-di-tert-butylperoxy-hexyne-3, and dicumyl peroxide are more preferable.

The thickness of the adhesive between the polyester film layer and the polyamide film layer is preferably about 0.1 to 5 μm, and more preferably about 0.5 to 3 μm.

The adhesive layer 13 may contain a colorant similar to that of the adhesive layer 2 described later.

From the viewpoint of improving the moldability of the battery packaging material of the present invention, it is preferable that a lubricant is present on the surface (surface opposite to the barrier layer) of the base material layer 1. When the lubricant is present on the surface of the base material layer 1, the amount of the lubricant present is not particularly limited, but is preferably about 3mg/m in an environment of 24 ℃ and 60% humidity²More preferably 4 to 15mg/m²About, more preferably 5 to 14mg/m²Left and right.

The lubricant is not particularly limited, but preferably includes an amide-based lubricant. Specific examples of the lubricant include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, and the like. Specific examples of the saturated fatty amide include lauramide, palmitamide, stearamide, behenamide, and hydroxystearamide. Specific examples of the unsaturated fatty 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 methylolstearylamide and the like. Specific examples of the saturated fatty acid bisamide include methylene bisstearamide, ethylene biscapramide, ethylene bislauramide, ethylene bisstearamide, ethylene bishydroxystearamide, ethylene bisbehenamide, hexylene bisstearamide, hexylene bisbehenamide, hexylene hydroxystearamide, N '-distearyladipamide, N' -distearylsebacamide, and the like. Specific examples of the unsaturated fatty acid bisamide include ethylene bisoleamide, ethylene biserucamide, hexamethylene bisoleamide, N '-dioleyl adipamide, N' -dioleyl sebacamide, and the like. Specific examples of the fatty acid ester amide include stearamide ethyl stearate. Specific examples of the aromatic bisamide include m-xylylene bisstearamide, m-xylylene bishydroxystearamide, and N, N' -distearyl isophthalamide. The lubricant may be used alone in 1 kind, or may be used in combination of 2 or more kinds.

The base material layer 1 may contain a lubricant. The lubricant present on the surface of the base material layer 1 may be a lubricant in which a lubricant contained in the resin constituting the base material layer 1 bleeds out, or a lubricant may be applied to the surface of the base material layer 1.

The thickness of the base layer 1 is preferably about 4 μm or more, more preferably about 10 to 75 μm, and even more preferably about 10 to 50 μm, from the viewpoint of reducing the thickness of the battery packaging material and producing a battery packaging material having excellent moldability.

[ adhesive layer 2]

In the battery packaging material of the present invention, the adhesive layer 2 is a layer provided between the base material layer 1 and the barrier layer 3 as necessary to strongly bond 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 for forming the adhesive layer 2 may be a two-component curing adhesive or a one-component curing adhesive. The bonding mechanism of the adhesive used for forming the adhesive layer 2 is not particularly limited, and any type such as a chemical reaction type, a solvent volatilization type, a hot melt type, and a hot press type may be used.

Specific examples of the adhesive component that can be used to form the adhesive layer 2 include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolyester; a polyether adhesive; a polyurethane adhesive; an epoxy resin; a phenolic 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, or can be used in combination of 2 or more. Among these adhesive components, a polyurethane adhesive is preferably used.

Examples of the polyurethane adhesive include the following adhesives: a polyurethane adhesive comprising a base containing a polyol component (A) and a curing agent containing a polyisocyanate component (B), wherein the polyol component (A) comprises a polyester polyol (A1), the polyester polyol (A1) is a polyester polyol having a number average molecular weight of 5000 to 50000 and comprising a polybasic acid component and a polyol component, and the polybasic acid componentThe base acid component contains 45 to 95 mol% of an aromatic multi-basic acid component per 100 mol% of the base acid component, and the tensile stress at 100% elongation of the adhesive layer is 100kg/cm²Above 500kg/cm²The following. The following adhesives may also be mentioned: a polyurethane adhesive for a battery packaging material, which contains a main agent and a polyisocyanate curing agent, wherein the main agent contains a polyol component (A) and a silane coupling agent (B), the polyol component (A) contains 5 to 50 mass% of a polyester polyol (A1) having a glass transition temperature of 40 ℃ or higher and 95 to 50 mass% of a polyester polyol (A2) having a glass transition temperature of less than 40 ℃, and the equivalent ratio of isocyanate groups contained in the curing agent to the total of hydroxyl groups and carboxyl groups derived from the polyol component (A) [ NCO ] is the equivalent ratio [ NCO [ ([ NCO ] ])]/([OH]+[COOH]) Is 1 to 30.

Further, there may be mentioned an adhesive containing a resin containing 1 or more kinds of resins (a) selected from modified polypropylene and polyacrylic resins, or a resin containing any one of coupling agents (B) (a) or (B)) including at least one kind of a silane coupling agent and a titanate coupling agent.

In addition, the adhesive layer 2 may contain a colorant. By containing the colorant in the adhesive layer 2, the battery packaging material can be colored. As the colorant, known substances such as pigments and dyes can be used. Further, only 1 kind of the colorant may be used, or 2 or more kinds may be mixed and used.

For example, specific examples of the inorganic pigment include carbon black and titanium oxide. Specific examples of the organic pigment include azo pigments, phthalocyanine pigments, and condensed ring pigments. Examples of azo pigments include soluble pigments such as watchung red and carmine 6C; insoluble azo pigments such as monoazo yellow, disazo yellow, pyrrazolone orange, pyrrazolone red, and permanent red; examples of the phthalocyanine pigment include copper phthalocyanine pigments, and blue pigments or green pigments which are metal-free phthalocyanine pigments; examples of the condensed system pigment include dioxazine violet and quinacridone violet. As the pigment, a pearl pigment, a fluorescent pigment, or the like can be used.

Among the colorants, carbon black is preferable, for example, in order to make the appearance of the battery packaging material black.

The average particle diameter of the pigment is not particularly limited, and may be, for example, about 0.05 to 5 μm, preferably about 0.08 to 2 μm. The average particle diameter of the pigment is a median diameter measured by a laser diffraction/scattering particle size distribution measuring apparatus.

The content of the pigment in the adhesive layer 2 is not particularly limited as long as the battery packaging material can be colored, and may be, for example, about 5 to 60 mass%.

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. [ coloring layer ]

The colored layer is a layer (not shown) provided between the base material layer 1 and the adhesive layer 2 as needed. By providing the coloring layer, the battery packaging material can be colored.

The colored layer can be formed by, for example, applying an ink containing a colorant to the surface of the base layer 1 or the surface of the barrier layer 3. As the colorant, a known colorant such as a pigment or a dye can be used. Further, only 1 kind of the colorant may be used, or 2 or more kinds may be mixed and used.

Specific examples of the coloring agent contained in the colored layer include the same coloring agents as those exemplified in the adhesive layer 2.

[ Barrier layer 3]

In the battery packaging material, the barrier layer 3 is a layer that enhances the strength of the battery packaging material and functions as a barrier layer for preventing water vapor, oxygen, light, and the like from entering the battery. The barrier layer 3 can 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. Specific examples of the metal constituting the barrier layer 3 include aluminum, stainless steel, and titanium steel, and aluminum is preferably used. The barrier layer 3 can be formed of a metal foil, a metal vapor deposition, or the like, preferably a metal foil, and more preferably an aluminum foil or a stainless steel foil. From the viewpoint of preventing the occurrence of wrinkles or pinholes in the barrier layer 3 when producing the packaging material for a battery, it is more preferably formed of 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).

Examples of the stainless steel foil include an austenitic stainless steel foil and a ferritic stainless steel foil. The stainless steel foil is preferably made of austenitic stainless steel.

Specific examples of austenitic stainless steel constituting the stainless steel foil include SUS304, SUS301, and SUS316L, and among them, SUS304 is particularly preferable.

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 the upper limit is preferably about 85 μm or less, more preferably about 50 μm or less, further preferably 40 μm or less, and the lower limit is preferably about 10 μm or more, and the range of the thickness can be, for example, about 10 to 85 μm, preferably about 10 to 50 μm, more preferably about 10 to 45 μm. Among them, in the case where the barrier layer 3 is formed of a stainless steel foil, the thickness of the stainless steel foil is preferably about 85 μm or less, more preferably about 50 μm or less, further preferably about 40 μm or less, further more preferably about 30 μm or less, particularly preferably about 25 μm or less, the lower limit is preferably about 10 μm or more, and preferable thickness ranges are about 10 to 85 μm or about 10 to 50 μm, more preferably about 10 to 40 μm, further more preferably about 10 to 30 μm, and further more preferably about 15 to 25 μm.

The barrier layer 3 is preferably subjected to chemical conversion treatment on at least one side, preferably both sides, for stabilization of adhesion, prevention of dissolution, corrosion, or the like. Here, the chemical conversion treatment means a treatment for forming an acid-resistant coating film on the surface of the barrier layer. When the acid-resistant coating film is formed on the surface of the barrier layer 3 of the present invention, the barrier layer 3 contains the acid-resistant coating film. As the chemical conversion treatment, for example, there are: chromate treatment using a chromic acid compound such as chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium dihydrogen phosphate, acetylacetone chromate, chromium chloride, chromium potassium sulfate, or the like; phosphoric acid chromate treatment using phosphoric acid compounds such as sodium phosphate, potassium phosphate, ammonium phosphate, polyphosphoric acid, and the like; chromate treatment using an aminated phenol polymer having a repeating unit represented by the following general formulae (1) to (4), and the like. 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 R²Each of which is the same or different, represents 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 linear or branched alkyl groups 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 R²Examples of the hydroxyalkyl group include a linear or branched alkyl group having 1 to 4 carbon atoms, which is substituted with 1 hydroxyl group, such as a hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, 3-hydroxypropyl group, 1-hydroxybutyl group, 2-hydroxybutyl group, 3-hydroxybutyl group, or 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. 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 repeating units represented by the general formulae (1) to (4) is, for example, preferably 500 to 100 ten thousand, more preferably 1000 to 2 ten thousand.

Further, as a chemical conversion treatment method for imparting corrosion resistance to the barrier layer 3, there can be mentioned: a method of coating a material in which fine particles of barium sulfate or a metal oxide such as alumina, titanium oxide, cerium oxide, or tin oxide are dispersed in phosphoric acid, and performing a sintering process at 150 ℃ or higher to form an acid-resistant coating on the surface of the barrier layer 3. Further, a resin layer obtained by crosslinking a cationic polymer with a crosslinking agent may be further formed on the acid-resistant coating film. 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 isocyanate group, glycidoxy group, carboxyl group and 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, for example, at least the surface on the inner layer side of the aluminum foil (barrier layer) may be degreased 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 a treatment liquid (aqueous solution) containing a metal phosphate such as Cr (chromium) phosphate, Ti (titanium) phosphate, Zr (zirconium) phosphate, or Zn (zinc) phosphate and a mixture of these metal salts as main components, a treatment liquid (aqueous solution) containing a mixture of a nonmetal salt of phosphoric acid and these nonmetal salts as main components, or a treatment liquid (aqueous solution) containing a mixture of these nonmetal salts and an aqueous synthetic resin such as an acrylic resin, a phenolic resin, or a urethane resin may be applied to the degreased surface by a known application method such as a roll coating method, a gravure printing method, or an immersion method, thereby forming an acid-resistant coating film. For example, when the treatment is carried out with a Cr (chromium) phosphate treatment liquid, the treatment is carried out with CrPO₄(chromium phosphate), AlPO₄(aluminum phosphate) and Al₂O₃(alumina), Al (OH)_x(aluminum hydroxide) AlF_xAn acid-resistant coating film made of (aluminum fluoride) or the like; when the treatment is carried out by using a Zn (zinc) phosphate treatment liquid, Zn is formed₂PO₄·4H₂O (Zinc phosphate hydrate), AlPO₄(aluminum phosphate) and Al₂O₃(alumina), Al (OH)_x(aluminum hydroxide))、AlF_xAn acid-resistant coating film made of (aluminum fluoride) or the like.

As another specific example of the method for providing the acid-resistant coating, for example, the acid-resistant coating can be formed by first performing degreasing treatment on at least the surface on 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 performing known anodization treatment on the degreased surface.

Further, as other examples of the acid-resistant coating film, a coating film of a phosphorus compound (for example, phosphate-based) or a chromium compound (for example, chromic acid-based) 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.

In addition, as another example of the acid-resistant coating, by forming an acid-resistant coating of a phosphorus compound (phosphate, etc.), a chromium compound (chromate, etc.), a fluoride, a triazine thiol compound, or the like, the following effects are exhibited: the method prevents delamination between aluminum and a base material layer during embossing, prevents dissolution and corrosion of the aluminum surface, particularly dissolution and corrosion of aluminum oxide present on the aluminum surface, due to hydrogen fluoride generated by the reaction of an electrolyte with water, improves the adhesiveness (wettability) of the aluminum surface, prevents delamination between the base material layer and aluminum during heat sealing, and prevents delamination between the base material layer and aluminum during press molding in the embossing type. Among the substances forming the acid-resistant coating, the aluminum surface is coated with an aqueous solution composed of three components, namely, a phenolic resin, a chromium fluoride (3) compound and phosphoric acid, and the treatment of drying and sintering is good.

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 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.

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 glycidoxy 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 chemical conversion treatment, or may be performed by 2 or more chemical conversion treatments in combination. These chemical conversion treatments may be carried out using 1 compound alone or 2 or more compounds in combination. Among the chemical conversion treatments, chromic acid chromate treatment, chromate treatment combining a chromic acid compound, a phosphoric acid compound, and an aminated phenol polymer, or the like is preferable.

Specific examples of the acid-resistant coating film include a coating film containing at least 1 of phosphate, chromate, fluoride, and triazine thiol. Further, an acid-resistant coating film containing a cerium compound is most 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 kind of the acid-resistant coating, or may be a combination of plural kinds of the acid-resistant coating. The acid-resistant coating is formed from 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 phosphoric acid and an aqueous synthetic resin after degreasing the chemical conversion-treated surface of the barrier layer.

Among these, composition analysis of the acid-resistant coating film can be performed by, for example, time-of-flight secondary ion mass spectrometry. By analyzing the composition of the acid-resistant coating film by time-of-flight secondary ion mass spectrometry, for example, secondary ions derived from a substance containing Ce, P and O (for example, Ce2 PO) are detected₄ ⁺、CePO₄ ^-Etc.) or, for example, from secondary ions including Cr, P, and O (e.g., CrPO)₂ ⁺、CrPO₄ ^-Etc. of at least 1).

The amount of the acid-resistant coating 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, the amount of the acid-resistant coating is 1m per one barrier layer 3²On the surface, the content of chromic acid compound is about 0.5 to 50mg, preferably about 1.0 to 40mg, the content of phosphorus compound is about 0.5 to 50mg, preferably about 1.0 to 40mg, and the content of 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, but is preferably about 1nm to 20 μm, more preferably about 1 to 100nm, and still more preferably about 1 to 50nm, from the viewpoint of the aggregating power of the coating and the adhesion to the barrier layer or the heat-sealable resin layer. 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 an electron-beam energy loss spectroscopy.

The chemical conversion treatment is performed by applying a solution containing a compound used 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 reaches 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 such degreasing treatment, the chemical conversion treatment of the surface of the barrier layer can be more effectively performed.

[ adhesive layer 4]

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

In the first battery packaging material of the present invention, in the thermo-mechanical analysis for measuring the displacement amount of the probe, the probe is provided on the surface of the adhesive layer 4 on the cross section of the battery packaging material, and when the probe is heated from 40 ℃ to 220 ℃ under the conditions that the set value of the deflection of the probe at the start of measurement is-4V and the temperature rise rate is 5 ℃/min, the temperature at which the position of the probe is lower than the initial value is 130 ℃ or lower. In the first battery packaging material of the present invention, since the adhesive layer 4 located between the barrier layer 3 and the heat-fusible resin layer 5 has such specific physical properties, the sealed state of the battery element can be maintained until the increase in pressure and temperature in the battery reaches a certain level, and at the time when the pressure and temperature in the battery continue to increase, fine cracks such as pinholes can be rapidly generated at the adhesive layer 4 or at the interface between the adhesive layer and the adjacent layer (barrier layer 3 or heat-fusible resin layer 5), and the battery can be smoothly opened.

More specifically, the heat-fusible resin layer 5 of the first battery packaging material of the present invention is heat-fused in a state of facing each other, and an aluminum plate as a dummy battery (dummy cell) and water as a substitute for the electrolyte are sealed with the battery packaging material, and when the temperature is raised to 130 ℃ under vacuum, the sealing is smoothly conducted at a temperature of 130 ℃ or lower. Among them, the following three mechanisms (see fig. 16 to 18) can be considered as detailed mechanisms. The left side of B in fig. 16 to 18 corresponds to the left side of C, and the right side of B corresponds to the right side of C.

As a first mechanism, the following can be considered: when the temperature is raised from the state a in fig. 16 until the battery reaches a certain temperature (for example, about 80 to 120 ℃), peeling occurs at least in part of the interface between the barrier layer 3 and the adhesive layer 4 (interface peeling) as shown in B in fig. 16, and at this time, the adhesive layer 4 and the heat-fusible resin layer 5 are formed into a bag shape (inner bag) and the state of sealing the battery element can be maintained. Next, as shown in C of fig. 16, a fine crack such as a pinhole (shown by H in fig. 16) is generated in the region (inner bag) of the adhesive layer 4 and the heat-fusible resin layer 5 peeled from the barrier layer 3, and it is considered that an opened state is formed under a smooth condition.

As a second mechanism, the following can be considered: when the temperature is raised from the state a in fig. 17 until the battery reaches a certain temperature (for example, about 80 to 120 ℃), as shown in B in fig. 17, at least a part of the inside of the adhesive layer 4 is peeled off in an aggregated state, and at this time, the part of the adhesive layer 4 where the peeling off in an aggregated state and the heat-fusible resin layer 5 in contact therewith are formed into a bag (inner bag), and the sealed state of the battery element is maintained. Next, as shown in C of fig. 17, it is considered that a fine crack such as a pinhole is generated in the region of the adhesive layer 4 where the aggregation peeling occurs and the heat-fusible resin layer 5 (inner bag) in contact therewith (shown in H of fig. 17), and the opened state is formed under a smooth condition.

As a third mechanism, the following can be considered: when the temperature is raised from the state a in fig. 18 until the battery reaches a certain temperature (for example, about 80 to 120 ℃), peeling occurs at least in part of the interface between the adhesive layer 4 and the heat-fusible resin layer 5 (interfacial peeling) as shown in B in fig. 18, and at this time, the heat-fusible resin layer 5 is formed into a bag (inner bag) and the battery element is maintained in a sealed state. Next, as shown in C of fig. 18, it is considered that a fine crack such as a pinhole is generated in the region (inner bag) of the heat-fusible resin layer 5 peeled from the adhesive layer 4 (shown by H of fig. 18), and the opened state is formed under a smooth condition.

However, when the adhesive layer 4 is formed of a plurality of layers, and when peeling occurs inside the adhesive layer 4, peeling may occur at least in part at the interface of the plurality of layers, and fine cracks such as pinholes may occur in the peeled area, resulting in an unsealed state under smooth conditions.

The interfacial peeling, the aggregation peeling, the formation of the inner bag, and the like as described above can be controlled by observing the inside of the battery after the opening.

The battery packaging material of the present invention is preferably used for a battery having an opening temperature set to about 120 ℃. The unsealing temperature is more preferably about 80 to 95 ℃.

The above-described evaluation of the sealing property (measurement of the unsealing temperature) can be carried out as described in examples by referring to JIS C8714: the method of 2007.

In the first battery packaging material, the temperature at which the position of the probe is lower than the initial value is preferably about 60 to 130 ℃, and more preferably about 60 to 90 ℃, from the viewpoint that the battery element can be sealed until the pressure and temperature in the battery increase to a certain level, and the battery can be quickly and smoothly unsealed when the pressure and temperature in the battery continue to increase. Particularly, the probe is positioned at a temperature lower than the initial value of about 60 to 90 ℃, so that the probe can be smoothly unsealed at an unsealing temperature of about 80 to 95 ℃.

From the same viewpoint, in the first battery packaging material of the present invention, in the thermo-mechanical analysis for measuring the displacement amount of the probe, the probe is provided on the surface of the adhesive layer 4 on the cross section of the battery packaging material, and when the probe is heated from 40 ℃ to 220 ℃ under the conditions that the set value of the deflection of the probe at the start of measurement is-4V and the temperature rise rate is 5 ℃/min, the temperature at which the position of the probe reaches the highest point is preferably about 100 ℃ or less, more preferably about 50 to 100 ℃, further preferably about 50 to 70 ℃, and further preferably about 50 to 65 ℃.

In the second battery packaging material of the present invention, in the thermo-mechanical analysis for measuring the displacement amount of the probe, the probe is provided on the surface of the adhesive layer 4 on the cross section of the battery packaging material, and when the probe is heated from 40 ℃ to 220 ℃ under the conditions that the set value of the deflection of the probe at the start of measurement is-4V and the temperature rise rate is 5 ℃/min, the temperature at which the position of the probe reaches the highest point is 100 ℃ or lower. In the second battery packaging material of the present invention, since the adhesive layer 4 located between the barrier layer 3 and the heat-fusible resin layer 5 has such specific physical properties, the sealed state of the battery element can be maintained until the increase in pressure and temperature in the battery reaches a certain level, and at the time when the pressure and temperature in the battery continue to increase, fine cracks such as pinholes can be rapidly generated at the adhesive layer 4 or at the interface between the adhesive layer and the adjacent layer (barrier layer 3 or heat-fusible resin layer 5), and the battery can be smoothly opened.

More specifically, the heat-fusible resin layer 5 of the second battery packaging material of the present invention is heat-fused in a state of facing each other, and an aluminum plate as a dummy battery and water as a substitute for the electrolyte are sealed with the battery packaging material, and the temperature is raised to 130 ℃ under vacuum, and the sealing is smoothly conducted at a temperature of 130 ℃ or lower. Among them, as detailed mechanisms, the above three mechanisms can be considered, as in the case of the first battery packaging material.

From the same viewpoint, in the second battery packaging material of the present invention, in the thermo-mechanical analysis for measuring the displacement amount of the probe, the probe is provided on the surface of the adhesive layer 4 on the cross section of the battery packaging material, and when the probe is heated from 40 ℃ to 220 ℃ under the conditions that the set value of the deflection of the probe at the start of measurement is-4V and the temperature increase rate is 5 ℃/min, the temperature at which the position of the probe reaches the highest point is preferably 50 to 100 ℃, and more preferably 50 to 70 ℃.

From the same viewpoint, in the second battery packaging material of the present invention, in the thermo-mechanical analysis for measuring the displacement amount of the probe, when the probe is provided on the surface of the adhesive layer 4 on the cross section of the battery packaging material and the probe is heated from 40 ℃ to 220 ℃ under the conditions that the set value of the deflection of the probe at the start of measurement is-4V and the temperature rise rate is 5 ℃/min, the temperature at which the position of the probe is lower than the initial value is preferably 130 ℃ or lower, more preferably about 60 to 130 ℃, and still more preferably about 60 to 90 ℃.

(measurement of Displacement amount of Probe)

In the thermomechanical analysis for measuring the displacement amount of the probe, for example, as shown in the conceptual diagram of fig. 5, first, the probe 11 of the thermomechanical analysis apparatus is set on the surface of the adhesive layer 4 in the cross section of the battery packaging material (measurement start a of fig. 5). The cross section at this time is a portion of the adhesive layer 4 exposed in cross section, which is cut in the thickness direction so as to pass through the center portion of the battery packaging material. Fig. 4 shows the probe installation position 4 a. The cutting can be performed using a commercially available rotary microtome or the like. Here, when measuring the displacement of a battery packaging material used for a battery in which an electrolyte or the like is sealed, the portion of the battery packaging material where the heat-fusible resin layers are heat-fused to each other is cut in the thickness direction in the same manner as in the above-described method and measured. As a device for thermal mechanical analysis, AN atomic force microscope equipped with a cantilever having a heating mechanism, for example, the afm plus system manufactured by ANASIS INSTRUMENTS corporation, can be used, and as a probe, a cantilever ThermLever AN2-200 (spring constant 0.5-3N/m) can be used. The radius of the tip of probe 11 was 30nm or less, the set value of Deflection (deflections) of probe 11 was-4V, and the temperature rising rate was 5 ℃/min. Next, when the probe is heated in this state, the surface of the adhesive layer 4 expands as shown in B of fig. 5 due to the heat from the probe, and the probe 11 is lifted, so that the position of the probe 11 is higher than the initial value (the position when the temperature of the probe is 40 ℃). When the heating temperature is further increased, the adhesive layer 4 is softened, and as shown in C of fig. 5, the probe 11 penetrates the adhesive layer 4, and the position of the probe 11 is lowered. In the thermomechanical analysis for measuring the displacement amount of the probe, the battery packaging material to be measured was at room temperature (25 ℃), and the probe heated to 40 ℃ was placed on the surface of the adhesive layer 4 to start the measurement. For the measurement of the amount of displacement of the probe, a cross section along the thickness direction of the battery packaging material was prepared, 5 points of the cross section were measured (see fig. 19), and the average value was taken as the measurement value. In addition, the thickness direction and the vertical direction of the cross section may be in any direction (for example, TD may be mentioned), and the temperature at which the position of the probe is lower than the initial value in any direction may be 130 ℃. The calibration was also performed 5 times, and the average value was obtained.

In the present invention, since the displacement amount of the probe is measured from the cross section of the laminate of the battery packaging material, the thermal performance of only the adhesive layer can be measured in a state close to the usage state of the battery, as compared with the case where the displacement amount is measured from the surface of the material (before the battery packaging material is formed) on which the adhesive layer is formed. That is, when the material of the adhesive layer is applied to a film base material or the like and the softening temperature or the like is measured from the surface thereof by TMA or the like, the thickness required for the measurement is 10 times or more thicker than the actual thickness of the adhesive layer, and the curing degree and the bonding state are different when the adhesive layer is actually used as a battery packaging material, and therefore the thermal properties are different. In this case, the influence of the thermal properties of the film base material and the like may be superimposed, and it cannot be said that the thermo-mechanical properties of only the adhesive layer are measured.

The adhesive layer 4 is formed of a resin capable of bonding the barrier layer 3 and the heat-fusible resin layer 5. As the resin used for forming the adhesive layer 4, the same resin as the adhesive exemplified in the adhesive layer 2, such as the adhesion mechanism and the type of the adhesive component, can be used. As the resin used for forming the adhesive layer 4, polyolefin-based resins such as polyolefin, cyclic polyolefin, carboxylic acid-modified polyolefin, and carboxylic acid-modified cyclic polyolefin exemplified in the above-described heat-sealable resin layer 5 can be used. That is, the resin constituting the adhesive layer 4 may or may not contain a polyolefin skeleton, and preferably contains a polyolefin skeleton. The resin constituting the adhesive 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 becomes small and may not be detected. In this case, the analysis can be performed by nuclear magnetic resonance spectroscopy.

From the viewpoint of improving the adhesion between the barrier layer 3 (or acid-resistant coating film) and the heat-fusible resin layer 5, the adhesive layer 4 preferably contains an acid-modified polyolefin. The acid-modified polyolefin is a polymer modified by block polymerization or graft polymerization of a polyolefin 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. Examples of the modified polyolefin include polyethylenes 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 (for example, a block copolymer of propylene and ethylene), a random copolymer of polypropylene (for example, 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.

Among the acid-modified polyolefins, maleic anhydride-modified polyolefins are particularly preferable, and maleic anhydride-modified polypropylene is more preferable in the adhesive layer 4.

The adhesive layer 4 is more preferably a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, from the viewpoint of further reducing the thickness of the battery packaging material and producing a battery packaging material having excellent shape stability after molding. The acid-modified polyolefin can be preferably exemplified by those described above.

The adhesive layer 4 is preferably a cured product of a resin composition containing an acid-modified polyolefin and at least 1 selected from a compound having an isocyanate group, a compound having an oxazoline group, and a compound having an epoxy group, and is particularly preferably a cured product of a resin composition containing an acid-modified polyolefin and at least 1 selected from a compound having an isocyanate group and a compound having an epoxy group. The adhesive layer 4 preferably contains at least 1 selected from a polyurethane resin, an ester resin, and an epoxy resin, and more preferably contains a polyurethane resin and an epoxy resin. As the ester resin, for example, an amide ester resin is preferable. Amide ester resins are typically formed by the reaction of a carboxyl group with an oxazoline group. The adhesive layer 4 is more preferably a cured product of a resin composition containing at least 1 of these resins and the acid-modified polyolefin. When an unreacted material of a compound having an isocyanate group, a compound having an oxazoline group, or a curing agent such as an epoxy resin remains in the adhesive layer 4, the presence of the unreacted material can be confirmed by a method selected from, for example, infrared spectroscopy, raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and the like.

In addition, from the viewpoint of further improving the adhesion of the barrier layer 3 (or acid-resistant coating film), the heat-fusible resin layer 5, and the adhesive layer 4, the adhesive layer 4 is preferably a cured product of a resin composition containing at least 1 kind of curing agent selected from an oxygen atom, a heterocyclic ring, a C ═ N bond, and a C — O — C bond. Examples of the curing agent having a heterocyclic ring include a curing agent having an oxazoline group, a curing agent having an epoxy group, and the like. Examples of the curing agent having a C ═ N bond include a curing agent having an oxazoline group and a curing agent having an isocyanate group. Examples of the curing agent having a C — O — C bond include a curing agent having an oxazoline group, a curing agent having an epoxy group, and a urethane resin. The cured product of the resin composition containing the curing agent in the adhesive layer 4 can be confirmed by, for example, Gas Chromatography Mass Spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry (TOF-SIMS), X-ray photoelectron spectroscopy (XPS), or the like.

The compound having an isocyanate group is not particularly limited, and a polyfunctional isocyanate compound is preferably used from the viewpoint of effectively improving the adhesion between the acid-resistant coating film and the adhesive layer 4. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having 2 or more isocyanate groups. Specific examples of the polyfunctional isocyanate-based curing agent include Pentane Diisocyanate (PDI), 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 content of the compound having an isocyanate group in the adhesive layer 4 is preferably in the range of 0.1 to 50 mass%, more preferably 0.5 to 40 mass% in the resin composition constituting the adhesive layer 4.

The oxazoline group-containing compound is not particularly limited as long as it is a compound having an oxazoline skeleton. Specific examples of the oxazoline group-containing compound include a compound having a polystyrene main chain, a compound having an acrylic main chain, and the like. Examples of commercially available products include Epocros series products produced by Nippon catalysts, Inc.

The proportion of the oxazoline group-containing compound in the adhesive layer 4 is preferably in the range of 0.1 to 50 mass%, more preferably in the range of 0.5 to 40 mass% in the resin composition constituting the adhesive layer 4. This can effectively improve the adhesion between the barrier layer 3 (or acid-resistant coating film) and the adhesive layer 4.

The epoxy resin is not particularly limited as long as it can form a crosslinked structure by epoxy groups present in the molecule, and a known epoxy resin can be used. The weight average molecular weight of the epoxy resin is preferably about 50 to 2000, more preferably about 100 to 1000, and still more preferably about 200 to 800. Wherein, in the present invention, the weight average molecular weight of the epoxy resin is a value measured by Gel Permeation Chromatography (GPC) measured under the condition that polystyrene is used as a standard sample.

Specific examples of the epoxy resin include glycidyl ether derivatives of trimethylolpropane, bisphenol a diglycidyl ether, modified bisphenol a diglycidyl ether, novolak glycidyl ether, glycerol polyglycidyl ether, and polyglycerol polyglycidyl ether. The epoxy resin may be used alone in 1 kind, or 2 or more kinds may be used in combination.

The proportion of the epoxy resin in the adhesive layer 4 is preferably in the range of 0.1 to 50 mass%, more preferably 0.5 to 40 mass% in the resin composition constituting the adhesive layer 4. This can effectively improve the adhesion between the barrier layer 3 (or acid-resistant coating film) and the adhesive layer 4.

In the present invention, when the adhesive layer 4 is a cured product of a resin composition containing at least 1 selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group and an epoxy resin, and the acid-modified polyolefin, the acid-modified polyolefin functions as a main agent, and the compound having an isocyanate group, the compound having an oxazoline group and the epoxy resin each function as a curing agent.

The thickness of the adhesive layer 4 is preferably about 30 μm or less, more preferably about 20 μm or less, and still more preferably about 5 μm or less. The lower limit is about 0.1 μm or more and about 0.5 μm or more. The thickness is preferably about 0.1 to 30 μm, about 0.1 to 20 μm, about 0.1 to 5 μm, about 0.5 to 30 μm, about 0.5 to 20 μm, or about 0.5 to 5 μm.

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 carbodiimide groups.

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 5 by the adhesive layer 4.

The content of the curing agent in the resin composition forming the adhesive layer 4 is preferably in the range of about 0.1 to 50 mass%, more preferably about 0.1 to 30 mass%, and still more preferably about 0.1 to 10 mass%.

The adhesive layer 4 can be formed using an adhesive, for example. Examples of the adhesive include an adhesive composition containing an amorphous polyolefin resin (a) having a carboxyl group, a polyfunctional isocyanate compound (B), and a tertiary amine (C) having no functional group reactive with the polyfunctional isocyanate compound (B), wherein the polyfunctional isocyanate compound (B) is contained in an amount of 0.3 to 10 moles per 1 mole of the total of the carboxyl groups, and the tertiary amine (C) is contained in an amount of 1 to 10 moles per the total of the carboxyl groups. The adhesive composition may further contain 20 to 90% by mass of the styrene-based thermoplastic elastomer (A), 10 to 80% by mass of the adhesion imparting agent (B), and 0.003 to 0.04mmol/g of active hydrogen derived from an amino group or a hydroxyl group per 100% by mass of the total of the styrene-based thermoplastic elastomer (A) and the adhesion imparting agent (B), wherein the active hydrogen derived from the functional group of the adhesion imparting agent (B) is 0 to 15 mol per 1 mol of the active hydrogen derived from the styrene-based thermoplastic elastomer (A), and the active hydrogen derived from the functional group of the adhesion imparting agent (B) is 3 to 15 mol per 1 mol of the total of the active hydrogen derived from the styrene-based thermoplastic elastomer (A) and the active hydrogen derived from the adhesion imparting agent (B), and a polyisocyanate (C) The polyisocyanate (C) is contained in a range of 150 moles of isocyanate groups.

In the adhesive layer 4, the temperature at which the position of the probe is lower than the initial value and the temperature at which the position of the probe is at the maximum can be adjusted to the above values not only by the type of resin contained in the adhesive but also by the molecular weight and the number of crosslinking points of the resin, the ratio and dilution ratio of the main agent and the curing agent, the drying temperature, the aging time, and the like.

The thickness of the adhesive layer 4 is not particularly limited as long as it can function as an adhesive layer, and when the adhesive exemplified in the adhesive layer 2 is used, it is preferably about 2 to 10 μm, and more preferably about 2 to 5 μm. When the resin exemplified in the heat-fusible resin layer 5 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, the thickness is preferably about 30 μm or less, more preferably about 0.1 to 20 μm, and still more preferably about 0.5 to 5 μm. In the case of the adhesive layer formed of the adhesive composition, the thickness after drying and curing is 1 to 30g/m²Left and right. When the adhesive layer 4 is a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, the adhesive layer 4 can be formed by applying the resin composition and curing the resin composition by heating or the like.

[ Heat-fusible resin layer 5]

In the battery packaging material of the present invention, the heat-fusible resin layer 5 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 5 is not particularly limited as long as it can be heat-sealed, and examples thereof include polyolefins, cyclic polyolefins, carboxylic acid-modified polyolefins, and carboxylic acid-modified cyclic polyolefins. That is, the resin constituting the heat-fusible resin layer 5 may or may not contain a polyolefin skeleton, and preferably contains a polyolefin skeleton. The resin constituting the heat-sealable resin layer 5 containing a polyolefin skeleton can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, or the likeThere is no particular limitation. 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 becomes 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 polyethylenes 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 (for example, a block copolymer of propylene and ethylene), a random copolymer of polypropylene (for example, 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, styrene, butadiene, isoprene, and the like. Examples of the cyclic monomer as a constituent monomer of 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 olefins are preferred, and norbornene is more preferred.

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

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

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

The heat-fusible resin layer 5 may be formed of 1 resin component alone, or may be formed of a blend polymer composed of 2 or more resin components. The heat-fusible resin layer 5 may be formed of only 1 layer, or may be formed of 2 or more layers using the same or different resin components.

In addition, from the viewpoint of improving moldability of the battery packaging material, a lubricant may be present on the surface of the heat-fusible resin layer 5 as needed. The lubricant is not particularly limited, and a known lubricant can be used, and examples thereof include the lubricant exemplified in the base layer 1. The lubricant may be used alone in 1 kind, or may be used in combination of 2 or more kinds. The amount of the lubricant present on the surface of the heat-sealable resin layer 5 is not particularly limited, but is preferably 10 to 50mg/m in an environment of 24 ℃ and 60% humidity from the viewpoint of improving moldability of the electronic packaging material²About 15 to 40mg/m is more preferable²Left and right.

The heat-fusible resin layer 5 may contain a lubricant. The lubricant present on the surface of the heat-fusible resin layer 5 may be one obtained by bleeding out a lubricant contained in the resin constituting the heat-fusible resin layer 5, or one obtained by applying a lubricant to the surface of the heat-fusible resin layer 5.

In the battery packaging material of the present invention, the sealing strength (N/15mm) of the part obtained by thermally welding the thermally-weldable resin layers 5 to each other at 120 ℃ is preferably 1/8 or less, more preferably 1/18 to 1/8, of the sealing strength (N/15mm) at 25 ℃.

In the battery packaging material of the present invention, the sealing strength of the portion obtained by heat-sealing the heat-sealable resin layers 5 to each other at 120 ℃ is preferably about 20N/15mm or less, more preferably about 18N/15mm or less, still more preferably about 15N/15mm or less, and the lower limit is preferably about 2N/15mm or more, still more preferably about 3N/15mm or more, and still more preferably about 5N/15mm or more. Preferable ranges of the sealing strength include about 2 to 20N/15mm, about 2 to 18N/15mm, about 2 to 15N/15mm, about 3 to 20N/15mm, about 3 to 18N/15mm, about 3 to 15N/15mm, about 5 to 20N/15mm, about 5 to 18N/15mm, and about 5 to 15N/15 mm.

In the battery packaging material of the present invention, the sealing strength of the portion obtained by heat-welding the heat-sealable resin layers 5 to each other at 100 ℃ is preferably about 30N/15mm or less, more preferably about 25N/15mm or less, still more preferably about 22.9N/15mm or less as the upper limit, and is preferably about 3N/15mm or more, still more preferably about 5N/15mm or more, still more preferably about 8N/15mm or more as the lower limit. Preferable ranges of the sealing strength include about 3 to 30N/15mm, about 3 to 25N/15mm, about 3 to 22.9N/15mm, about 5 to 30N/15mm, about 5 to 25N/15mm, about 5 to 22.9N/15mm, about 8 to 30N/15mm, about 8 to 25N/15mm, and about 8 to 22.9N/15 mm.

(method of measuring seal Strength)

Seal strength of the battery packaging material at each measurement temperature was measured in accordance with JIS K7127: 1999. As a test piece, a battery packaging material was prepared by cutting the width of TD (Transverse Direction) into a long strip of 15 mm. Specifically, as shown in fig. 14, first, the battery packaging material is cut into 60mm (td) x 200mm (MD (Machine Direction)) (fig. 14 a). Next, the battery packaging material is folded in two in the MD direction at the position of the fold P (middle of MD) so that the heat-fusible resin layers face each other (fig. 14 b). The heat-sealable resin layers were heat-sealed to each other at a sealing width of 7mm, a temperature of 190 ℃, a surface pressure of 1.0MPa, and a time of 3 seconds on the inner side in the MD direction of about 10mm from the fold P (FIG. 14 c). In fig. 14c, the hatched portion S is a portion heat-sealed. Subsequently, a test piece was obtained by cutting in the MD direction (cutting at the position of the two-dot chain line in fig. 14 d) so that the width in the TD direction was 15mm (fig. 14 e). Next, the test piece 13 was left at each measurement temperature for 2 minutes, and the heat-fusible resin layer of the heat-fused portion was peeled off at a speed of 300 mm/minute by a tensile tester under each measurement temperature environment (fig. 15). The maximum strength at the time of peeling was defined as the sealing strength (N/15 mm). In the measurement of the sealing strength, there are a case where the test piece 13 shown in fig. 15 is peeled (broken) at the heat seal interface a and a case where the test piece 13 is broken at a portion different from the heat seal interface a (for example, at a position B in fig. 15). When the test piece 13 was broken, the breaking strength was defined as the sealing strength. The distance between the clamps was 50 mm.

When the seal strength is measured, the test piece may be broken at a position different from the seal portion without peeling at the seal portion. This phenomenon occurs when the peel strength of the seal portion is greater than the rupture strength of the test piece. When the test piece was broken at a position different from the sealed portion, the seal strength was evaluated to be equal to or higher than the breaking strength. In the MD and TD of the battery packaging material, for example, the rolling direction of the aluminum foil or the like constituting the barrier layer is MD, and the direction perpendicular to the MD on the same plane is TD. The rolling direction of the aluminum foil or the like can be confirmed from the rolling marks of the aluminum foil or the like.

The thickness of the heat-fusible resin layer 5 is not particularly limited as long as it can function as a heat-fusible resin layer, and examples thereof include about 100 μm or less, preferably about 85 μm or less, and more preferably about 15 to 85 μm. Among them, for example, when the thickness of the adhesive layer 4 is 10 μm or more, the thickness of the heat-fusible resin layer 5 is preferably about 85 μm or less, and preferably about 15 to 45 μm; for example, when the thickness of the adhesive layer 4 is less than about 10 μm, the thickness of the heat-fusible resin layer 5 is preferably about 20 μm or more, and more preferably about 35 to 85 μm.

[ surface coating layer 6]

In the battery packaging material of the present invention, the surface coating layer 6 may be provided on the base material layer 1 (on the side of the base material layer 1 opposite to the barrier layer 3) as necessary in order to improve design properties, electrolyte resistance, scratch resistance, moldability, and the like. The surface coating layer 6 is a layer located at the outermost layer when the battery is assembled.

The surface coating layer 6 can be formed of, for example, polyvinylidene chloride, polyester resin, polyurethane resin, acrylic resin, epoxy resin, or the like. Of these, the surface coating layer 6 is preferably formed of a two-liquid curable resin. Examples of the two-liquid curable resin for forming the surface coating layer 6 include two-liquid curable urethane resins, two-liquid curable polyester resins, and two-liquid curable epoxy resins. Further, an additive may be blended in the surface coating layer 6. The additive added may function as a matting agent, for example, and the surface coating layer may function as a matting layer.

Examples of the additive include fine particles having a particle diameter of 0.5nm to 5 μm. The material of the additive is not particularly limited, and examples thereof include metals, metal oxides, inorganic substances, and organic substances. The shape of the additive is not particularly limited, and examples thereof include spherical, fibrous, plate-like, amorphous, and hollow spherical shapes. Specific examples of the additive include talc, silica, graphite, kaolin, montmorillonite, synthetic mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, aluminum oxide, carbon black, carbon nanotubes, high-melting nylon, crosslinked acrylic acid, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, and nickel. These additives may be used alone in 1 kind, or may be used in combination of 2 or more kinds. Among these additives, silica, barium sulfate, and titanium oxide are preferable from the viewpoints of dispersion stability, cost, and the like. The additive may be subjected to various surface treatments such as an insulating treatment and a high-dispersibility treatment.

The method for forming the surface coating layer 6 is not particularly limited, and for example, a method of applying a two-liquid curable resin for forming the surface coating layer 6 on one surface of the base material layer 1 may be mentioned. When the additive is blended, the additive may be added to the two-liquid curable resin, mixed, and applied.

The thickness of the surface coating layer 6 is not particularly limited as long as the above function as the surface coating layer 6 can be exerted, and for example, the thickness is about 0.5 to 10 μm, preferably about 1 to 5 μm.

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, in the method for producing the first battery packaging material of the present invention, the following methods may be mentioned: the method comprises a step of sequentially laminating at least a base material layer, a barrier layer, an adhesive layer and a heat-fusible resin layer to obtain a laminate, wherein the adhesive layer satisfies the following conditions: in the thermomechanical analysis for measuring the displacement of the probe, the probe is arranged on the surface of the bonding layer of the cross section of the laminated body, and when the probe is heated from 40 ℃ to 220 ℃ under the conditions that the deflection of the probe is set to-4V and the heating rate is 5 ℃/min, the temperature at which the position of the probe is lower than the initial value is 130 ℃ or lower. In addition, in the method for producing the second battery packaging material of the present invention, the following method may be mentioned: the method comprises a step of sequentially laminating at least a base material layer, a barrier layer, an adhesive layer and a heat-fusible resin layer to obtain a laminate, wherein the adhesive layer satisfies the following conditions: in the thermomechanical analysis for measuring the displacement amount of the probe, the probe is arranged on the surface of the bonding layer of the cross section of the laminated body, and when the probe is heated from 40 ℃ to 220 ℃ under the conditions that the set value of the deflection of the probe at the start of measurement is-4V and the heating rate is 5 ℃/min, the temperature at which the position of the probe reaches the highest point is 100 ℃ or less.

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") in which a base material layer 1, an adhesive layer 2, and a barrier layer 3 are laminated in this order is formed. Specifically, the laminate a was formed by a dry lamination method as follows: the adhesive used for forming the adhesive layer 2 is applied on the base material layer 1 or the barrier layer 3 whose surface has been subjected to chemical conversion treatment as necessary by a coating method such as a gravure coating method or a roll coating method, and dried, and then the barrier layer 3 or the base material layer 1 is laminated, and the adhesive layer 2 is cured.

Next, the adhesive layer 4 and the heat-fusible resin layer 5 are sequentially laminated on the barrier layer 3 of the laminate a. For example, the following methods can be cited: (1) a method of laminating the barrier layer 3 of the laminate a by co-extrusion of the adhesive layer 4 and the heat-fusible resin layer 5 (co-extrusion lamination method); (2) a method of forming a laminate in which the adhesive layer 4 and the heat-fusible resin layer 5 are separately laminated, and laminating them 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 4 is extruded or solution-coated on the barrier layer 3 of the laminate a, dried at a high temperature, and then laminated by a method such as sintering, and a heat-fusible resin layer 5 previously formed into a sheet shape is laminated on the adhesive layer 4 by a heat lamination method; (4) a method (composite lamination method) in which the laminate a and the heat-fusible resin layer 5 are bonded to each other by the adhesive layer 4 while the molten adhesive layer 4 is poured between the barrier layer 3 of the laminate a and the heat-fusible resin layer 5 formed in a sheet shape in advance.

When the surface coating layer 6 is provided, the surface coating layer 6 is laminated on the surface of the base material layer 1 opposite to the barrier layer 3. The surface coating layer 6 can be formed by, for example, applying the resin for forming the surface coating layer 6 to the surface of the base material layer 1. The order of the step of laminating the barrier layer 3 on the surface of the base material layer 1 and the step of laminating the surface coating layer 6 on the surface of the base material layer 1 is not particularly limited. For example, the surface coating layer 6 may be formed on the surface of the base material layer 1, and then the barrier layer 3 may be formed on the surface of the base material layer 1 opposite to the surface coating layer 6.

In this manner, a laminate comprising the surface coating layer 6 provided as needed, the base material layer 1, the adhesive layer 2 provided as needed, the barrier layer 3 whose surface is subjected to chemical conversion treatment as needed, the adhesive layer 4 provided as needed, and the heat-sealable resin layer 5 is formed, and heat treatment such as heat roller contact type, hot air type, near infrared type, or far infrared type may be further performed to enhance the adhesiveness of the adhesive layer 2 or the adhesive layer 4. The conditions for such heat treatment include, for example, 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, etc. as necessary for improving or stabilizing suitability for film formation, lamination, 2-pass processing (bag formation, embossing) of the final product, etc.

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 produced 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, with the battery packaging material of the present invention, a battery element having at least a positive electrode, a negative electrode, and an electrolyte is covered so that flange portions (regions where heat-fusible resin layers contact each other) can be formed at the peripheral edges of the battery element in a state where metal terminals to which the positive electrode and the negative electrode are connected respectively protrude outward, and the heat-fusible resin layers of the flange portions are heat-sealed and sealed with each other, whereby a battery using the battery packaging material can be provided. 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 (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 secondary batteries are preferred. The type of secondary battery to which the battery packaging material of the present invention can be 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 as the objects of application 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.

< production of packaging Material for Battery >

Example 1

As the base layer, a laminated film obtained by laminating a polyethylene terephthalate film and a nylon film by coextrusion and biaxially stretching the laminated film was prepared. In this laminated film, a biaxially stretched polyethylene terephthalate film (thickness: 5 μm) and a biaxially stretched nylon film (thickness: 20 μm) were bonded together with an adhesive (thickness: 1 μm) using a resin composition containing a modified thermoplastic resin graft-modified with an unsaturated carboxylic acid derivative component. Then, a barrier layer composed of an aluminum foil (JIS H4160: 1994A 8021H-O, thickness 40 μm) having both sides chemically treated and provided with an acid-resistant coating was laminated on the surface of the biaxially stretched nylon film side by a dry lamination method. Specifically, a two-pack urethane adhesive (a polyol compound and an aromatic isocyanate compound) was applied to one surface of the aluminum foil, and an adhesive layer (thickness 3 μm) was formed on the barrier layer. Next, the adhesive layer on the barrier layer and the biaxially stretched nylon film side of the base material layer were laminated, and then subjected to aging treatment at 40 ℃ for 24 hours, thereby producing a biaxially stretched polyethylene terephthalate film/adhesive/biaxially stretched nylon film/adhesive layer/barrier layer laminate.

Among them, the aluminum foil used as the barrier layer has an acid-resistant coating film containing cerium oxide and phosphate. Analysis of the acid-resistant coating was performed as follows. First, the barrier layer and the cured resin layer are torn apart. At this time, water, an organic solvent, an aqueous solution of an acid or an alkali, or the like is not used, and physical peeling is performed. After the barrier layer and the cured resin layer are peeled off from each other, the cured resin remains on the surface of the barrier layerThe resin layer, and thus the remaining cured resin layer, was removed by etching with Ar-GCIB. The surface of the barrier layer thus obtained was analyzed for an acid-resistant coating by time-of-flight secondary ion mass spectrometry. As a result, Ce was detected from the acid-resistant coating film₂PO₄ ⁺、CePO₄ ^-And the like secondary ions composed of Ce, P and O. The details of the measurement apparatus and the measurement conditions of the time-of-flight secondary ion mass spectrometry are as follows.

A measuring device: SIMS5, time-of-flight type secondary ION mass spectrometer TOF manufactured by ION-TOF corporation

Measurement conditions

Primary ion: double charged ions of bismuth cluster (Bi3+ +)

Primary ion acceleration voltage: 30kV

Mass range (m/z): 0 to 1500

Measurement range: 100 μm × 100 μm

Scanning number: 16 scans/cycles

Number of pixels (1 side): 256pixel

Etching ions: ar gas cluster ion beam (Ar-GCIB)

Etching ion acceleration voltage: 5.0kV

Next, an adhesive (cured thickness: 2 μm) containing an amorphous polyolefin resin having a carboxyl group and a polyfunctional isocyanate compound was applied and dried at 100 ℃, and the barrier layer side of the obtained laminate and an unstretched polypropylene film (thickness: 80 μm) were passed between 2 rolls set at 60 ℃ to bond them, thereby laminating an adhesive layer/heat-fusible resin layer on the metal foil. Then, the obtained laminate was cured (aged) at 40 ℃ for 1 day and at 40 ℃ for 5 days to obtain a battery packaging material in which a biaxially stretched polyethylene terephthalate film (5 μm)/an adhesive (1 μm)/a biaxially stretched nylon film (20 μm)/an adhesive layer (3 μm)/a barrier layer (40 μm)/an adhesive layer (2 μm)/an unstretched polypropylene film (80 μm) were laminated in this order. The layer structure of the battery packaging material is shown in table 1. Erucamide as a lubricant is present on the surface of the innermost layer side (the side opposite to the barrier layer) of the unstretched polypropylene film from the viewpoint of improving the moldability of the battery packaging material.

Example 2

A battery packaging material was obtained by laminating biaxially stretched polyethylene terephthalate film (5 μm)/adhesive (1 μm)/biaxially stretched nylon film (20 μm)/adhesive layer (3 μm)/barrier layer (40 μm)/adhesive layer (2 μm)/unstretched polypropylene film (40 μm) in this order in the same manner as in example 1, except that an unstretched polypropylene film (40 μm) was used instead of the unstretched polypropylene film (80 μm). Erucamide as a lubricant is present on the surface of the innermost layer side (the side opposite to the barrier layer) of the unstretched polypropylene film from the viewpoint of improving the moldability of the battery packaging material. The layer structure of the battery packaging material is shown in table 1. Among them, the aluminum foil used as the barrier layer has an acid-resistant coating film containing cerium oxide and phosphate. The analysis result of the acid-resistant coating was the same as in example 1.

Example 3 and comparative example 1

As the substrate layer, a biaxially stretched polyethylene terephthalate film (thickness: 12 μm) and a biaxially stretched nylon film (thickness: 15 μm) were laminated by a dry lamination method to prepare laminated films. In this laminated film, a biaxially stretched polyethylene terephthalate film and a biaxially stretched nylon film were bonded to each other with a polyurethane adhesive (thickness after curing: 3 μm) using a polyol and an isocyanate-based curing agent. Then, a barrier layer composed of an aluminum foil (JIS H4160: 1994A 8021H-O, thickness 40 μm) having both sides chemically treated and provided with an acid-resistant coating was laminated on the surface of the biaxially stretched nylon film side by a dry lamination method. Specifically, a two-pack urethane adhesive (a polyol compound and an aromatic isocyanate compound) was applied to one surface of the aluminum foil, and an adhesive layer (thickness 3 μm) was formed on the barrier layer. Then, the adhesive layer on the barrier layer and the biaxially stretched nylon film side of the base material layer were laminated, and then subjected to aging treatment at 40 ℃ for 24 hours to prepare a laminate of a biaxially stretched polyethylene terephthalate film/adhesive/biaxially stretched nylon film/adhesive layer/barrier layerAnd (3) a body. Among them, the aluminum foil used as the barrier layer has an acid-resistant coating film containing chromium oxide and phosphate. Analysis of the acid-resistant coating on the barrier layer was performed by time-of-flight secondary ion mass spectrometry in the same manner as in example 1. As a result, CrPO was detected from the acid-resistant coating film₂ ⁺、CrPO₄ ^-And the like, secondary ions composed of Cr, P, and O.

Next, in example 3, an elastic adhesive composition containing a polyolefin polyol and a polyfunctional isocyanate curing agent (thickness after curing: 3 μm) was used, and the barrier layer side of the obtained laminate was bonded to an unstretched polypropylene film (thickness: 80 μm), thereby laminating an adhesive layer/heat-sealable resin layer on the barrier layer. Subsequently, the obtained laminate was aged at 80 ℃ for 24 hours and finally heated at 190 ℃ for 2 minutes.

On the other hand, in comparative example 1, the resin composition containing the acid-modified polyolefin and the epoxy resin was applied to the barrier layer side of the obtained laminate so that the thickness after curing became 3 μm, and dried at 80 ℃ for 60 seconds to form an adhesive layer. Subsequently, an unstretched polypropylene film (CPP) was laminated by a dry lamination method from above the adhesive layer to obtain a heat-sealable resin layer. The obtained laminates were aged at 70 ℃ for 24 hours, respectively.

Through the above-described steps, a battery packaging material was obtained in which a biaxially stretched polyethylene terephthalate film (12 μm)/an adhesive (3 μm)/a biaxially stretched nylon film (15 μm)/an adhesive layer (3 μm)/a barrier layer (40 μm)/an adhesive layer (3 μm)/an unstretched polypropylene film (80 μm) were laminated in this order in example 3 and comparative example 1. Among them, erucamide as a lubricant is present on the surface of the innermost layer side (the side opposite to the barrier layer) of the unstretched polypropylene film from the viewpoint of improving the moldability of the battery packaging material. The layer structure of the battery packaging material is shown in table 1.

Example 4

As the base material layer, a biaxially stretched nylon film (thickness 25 μm) was prepared. Then, a barrier layer composed of a pair of a barrier layer and a pair of a barrier layer is laminated on the surface of the biaxially stretched nylon film by a dry lamination methodAn aluminum foil (JIS H4160: 1994A 8021H-O, thickness 40 μm) having both surfaces subjected to chemical conversion treatment and provided with an acid-resistant coating. Specifically, a two-pack urethane adhesive (a polyol compound and an aromatic isocyanate compound) was applied to one surface of the aluminum foil, and an adhesive layer (thickness 3 μm) was formed on the barrier layer. Next, the adhesive layer on the barrier layer and the biaxially stretched nylon film were laminated, and then subjected to aging treatment at 40 ℃ for 24 hours, thereby producing a biaxially stretched nylon film/adhesive layer/barrier layer laminate. Among them, the aluminum foil used as the barrier layer has an acid-resistant coating film containing chromium oxide and phosphate. The analysis of the acid-resistant coating on the barrier layer was performed by the time-of-flight secondary ion mass spectrometry in the same manner as in example 1. As a result, CrPO was detected from the acid-resistant coating film₂ ⁺、CrPO₄ ^-And the like, secondary ions composed of Cr, P, and O.

Next, in example 4, an elastic adhesive composition containing a polyolefin polyol and a polyfunctional isocyanate curing agent (thickness after curing: 3 μm) was used, and the barrier layer side of the obtained laminate was bonded to an unstretched polypropylene film (thickness: 40 μm), to laminate an adhesive layer/heat-sealable resin layer on the barrier layer. Then, the obtained laminate was aged at 80 ℃ for 24 hours and finally heated at 190 ℃ for 2 minutes to obtain a battery packaging material in which a biaxially stretched nylon film (25 μm)/an adhesive layer (3 μm)/a barrier layer (40 μm)/an adhesive layer (3 μm)/an unstretched polypropylene film (40 μm) were laminated in this order. Among them, erucamide as a lubricant is present on the surface of the innermost layer side (the side opposite to the barrier layer) of the unstretched polypropylene film from the viewpoint of improving the moldability of the battery packaging material. The layer structure of the battery packaging material is shown in table 1.

Comparative example 2

As the base layer, a biaxially stretched nylon film (thickness 15 μm) was prepared. Then, a barrier layer composed of an aluminum foil (JIS H4160: 1994A 8021H-O, thickness 35 μm) having both sides chemically treated and provided with an acid-resistant coating was laminated on the surface of the biaxially stretched nylon film side by a dry lamination method. Specifically, in aluminumOne side of the foil was coated with a two-pack urethane adhesive (a polyol compound and an aromatic isocyanate compound) to form an adhesive layer (thickness 3 μm) on the barrier layer. Next, the adhesive layer on the barrier layer and the biaxially stretched nylon film were laminated, and then subjected to aging treatment at 40 ℃ for 24 hours, thereby producing a biaxially stretched nylon film/adhesive layer/barrier layer laminate. Among them, the aluminum foil used as the barrier layer has an acid-resistant coating film containing chromium oxide and phosphate. The analysis of the acid-resistant coating film on the barrier layer was performed by time-of-flight secondary ion mass spectrometry in the same manner as in example 1. As a result, CrPO was detected from the acid-resistant coating film₂ ⁺、CrPO₄ ^-And the like, secondary ions composed of Cr, P, and O.

Next, a resin composition containing an acid-modified polyolefin and an epoxy resin was applied to the barrier layer side of the obtained laminate so that the thickness after curing became 3 μm, and the laminate was dried at 80 ℃ for 60 seconds to form an adhesive layer. Subsequently, an unstretched polypropylene film (CPP, 30 μm) was laminated by a dry lamination method from above the adhesive layer to form a heat-weldable resin layer. The obtained laminates were aged at 70 ℃ for 24 hours, and the biaxially stretched nylon film (15 μm)/adhesive layer (3 μm)/barrier layer (35 μm)/adhesive layer (3 μm)/unstretched polypropylene film (30 μm) obtained were laminated in this order to obtain a battery packaging material. Among them, erucamide as a lubricant is present on the surface of the innermost layer side (the side opposite to the barrier layer) of the unstretched polypropylene film from the viewpoint of improving the moldability of the battery packaging material. The layer structure of the battery packaging material is shown in table 1.

Example 5

As the substrate layer, a biaxially stretched polyethylene terephthalate film (thickness 9 μm) was prepared. Next, a metal foil composed of a stainless steel foil (austenitic stainless steel foil, 20 μm thick) having both surfaces subjected to chemical conversion treatment and provided with an acid-resistant coating was laminated on one surface of the base material layer by a dry lamination method. Specifically, a two-pack polyurethane adhesive (10% by mass of a resin comprising a polyol compound and an aromatic isocyanate compound) was applied to one surface of a base layerCarbon black was blended in an amount), and an adhesive layer (thickness 3 μm) was formed on the base material layer. Next, the adhesive layer on the base layer and one surface of the stainless steel foil having the acid-resistant coating film were laminated, and then subjected to aging treatment at 40 ℃ for 24 hours, thereby producing a biaxially stretched polyethylene terephthalate film/adhesive layer/barrier layer laminate. Among them, the stainless steel foil used as the barrier layer has an acid-resistant coating film containing chromium oxide and phosphate. The analysis of the acid-resistant coating film on the barrier layer was performed by time-of-flight secondary ion mass spectrometry in the same manner as in example 1. As a result, CrPO was detected from the acid-resistant coating film₂ ⁺、CrPO₄ ^-And the like, secondary ions composed of Cr, P, and O.

Next, an adhesive (cured thickness: 2 μm) composed of an amorphous polyolefin resin having a carboxyl group and a polyfunctional isocyanate compound was applied and dried at 100 ℃, and the barrier layer side of the obtained laminate and an unstretched polypropylene film (CPP, thickness: 23 μm) were passed between 2 rolls set at 60 ℃ to bond them, thereby laminating an adhesive layer/heat-fusible resin layer on the barrier layer. Next, an ink obtained by mixing a resin (80 mass%) containing a polyester polyol and an isocyanate-based curing agent and silica particles (20 mass%) was printed on the surface of the base material layer by gravure coating, thereby forming a surface coating layer (matte layer) having a thickness of 3 μm. Then, the obtained laminate was cured (aged) at 40 ℃ for 1 day and at 40 ℃ for 5 days to obtain a battery packaging material in which a matte layer (3 μm)/biaxially stretched polyethylene terephthalate film (9 μm)/adhesive layer (3 μm)/barrier layer (20 μm)/adhesive layer (3 μm)/unstretched polypropylene film (23 μm) were laminated in this order. Among them, erucamide as a lubricant is present on the surface of the innermost layer side (the side opposite to the barrier layer) of the unstretched polypropylene film from the viewpoint of improving the moldability of the battery packaging material. The layer structure of the battery packaging material is shown in table 1.

Comparative example 3

In comparative example 3, the aging conditions of the adhesive layer were changed from those in example 3 to prepare a battery packaging material. Specifically, in comparative example 3, a battery packaging material was obtained by laminating biaxially stretched polyethylene terephthalate film (12 μm)/adhesive (3 μm)/biaxially stretched nylon film (15 μm)/adhesive layer (3 μm)/barrier layer (40 μm)/adhesive layer (3 μm)/non-stretched polypropylene film (80 μm) in this order, except that "aging at 80 ℃ for 24 hours and finally heating at 190 ℃ for 2 minutes" was carried out in the temperature environment of 60 ℃ for 12 hours, then aging at 80 ℃ for 72 hours and finally heating at 190 ℃ for 2 minutes "in place of the above-mentioned aging conditions" for the laminate in example 3. Among them, in comparative example 3, erucamide as a lubricant was present on the surface of the innermost layer side (the side opposite to the barrier layer) of the unstretched polypropylene film, from the viewpoint of improving the moldability of the battery packaging material, as in example 3. The layer structure of the battery packaging material is shown in table 1.

[ Table 1]

	Layer structure of battery packaging material
		EXAMPLE 1	PET (5)/AD (1)/Ny (20)/DL (3)/ALM (40)/adhesive layer (2)/CPP (80)
Example 2	PET (5)/AD (1)/Ny (20)/DL (3)/ALM (40)/adhesive layer (2)/CPP (40)
		Example 3	PET (12)/DL (3)/Ny (15)/DL (3)/ALM (40)/adhesive layer (3)/CPP (80)
Example 4	Ny (25)/DL (3)/ALM (40)/adhesive layer (3)/CPP (40)
		Comparative example 1	PET (12)/DL (3)/Ny (15)/DL (3)/ALM (40)/adhesive layer (3)/CPP (80)
Comparative example 2	Ny (15)/DL (3)/ALM (35)/adhesive layer (3)/CPP (30)
		Example 5	Extinction layer (3)/PET (9)/DL (3)/SUS (20)/adhesive layer (3)/CPP (23)
Comparative example 3	PET (12)/DL (3)/Ny (15)/DL (3)/ALM (40)/adhesive layer (3)/CPP (80)

In table 1, the numerical values in parentheses in the layer structure represent thicknesses (μm). Further, PET represents polyethylene terephthalate, Ny represents nylon, AD represents an adhesive layer formed by coextrusion, DL represents an adhesive layer formed by dry lamination, ALM represents aluminum foil, and CPP represents a heat-fusible resin layer formed of non-stretched polypropylene.

< measurement of Displacement amount of Probe Using device for thermomechanical analysis >

The probe was placed on the surface of the adhesive layer of the cross section of each battery packaging material (the radius of the tip of the probe was 30nm or less, and the set value of the Deflection (deflections) of the probe was-4V), the probe was heated from 40 ℃ (temperature rise rate 5 ℃/min) to a predetermined temperature (the temperature at the right end of the plotted point shown in the curves of fig. 6 to 11), and the amount of displacement of the probe was measured. The details of the measurement conditions are as follows. As a device for thermal mechanical analysis, afm plus system manufactured by ANASIS INSTRUMENTS was used, and as a probe, cantilever ThermaLever AN2-200 (spring constant 0.5-3N/m) was used. The calibration was carried out using 3 types of the accompanying samples (polycaprolactam (melting point 55 ℃ C.), polyethylene (melting point 116 ℃ C.), and polyethylene terephthalate (melting point 235 ℃ C.), with an applied voltage of 0.1 to 10V, a velocity of 0.2V/sec, and a set value of Deflection (deflections) of-4V. Curves showing the relationship between the heating temperature and the displacement (deflection (v)) of the probe position are shown in fig. 6 (example 1), fig. 7 (example 2), fig. 8 (example 3), fig. 9 (example 4), fig. 10 (comparative example 1), and fig. 11 (comparative example 2), respectively. As shown in fig. 6 to 9, in the battery packaging materials obtained in examples 1 to 4, in the thermo-mechanical analysis for measuring the displacement amount of the probe, when the probe was heated from 40 ℃ to 220 ℃, the position of the probe was lower than the initial value at a temperature of 130 ℃. In examples 1 to 4, it is understood that the temperature at which the position of the probe reaches the maximum is 100 ℃. On the other hand, as shown in fig. 10 and 11, in the battery packaging materials obtained in comparative examples 1 and 2, in the thermo-mechanical analysis for measuring the displacement amount of the probe, the position of the probe was not lower than the initial value when the probe was heated from 40 ℃ to 220 ℃. The displacement (deflection (v)) of the position indicates the position (warp) of the probe tip, and a larger value indicates a state in which the probe tip is moved upward (the probe is tilted upward). For the measurement of the displacement amount of the probe, a cross section along the TD and the thickness direction was formed on the battery packaging material, and 5 points of the cross section were measured (see fig. 19) to obtain an average value. The calibration was also performed 5 times, and the average value was obtained.

(evaluation of sealing Property)

The sealing properties of each battery packaging material can be evaluated by a method according to JIS C8714: 2007. As shown in FIG. 12, each of the battery packaging materials was cut into 80Mm (MD) X160 mm (TD) (FIG. 12 a). Next, from the heat-fusible resin layer side, a molding die (female type) having a diameter of 31.6mm (md) × 54.5mm (TD) and a molding die (male type) corresponding thereto were cold-molded at a pressing pressure of 0.1MPa to a depth of 3.0mm from the center of the TD on one side, and a concave portion M was formed at the center portion (fig. 12 a). In addition, the clearance between the male and female types was 0.3 mm. Next, the molded battery packaging material is folded in two in the TD direction at the position of the fold P (middle of TD) with the concave portion M inside (fig. 12 b). Subsequently, the overlapped portions of the heat-sealable resin layers were heat-sealed at 2 places (190 ℃, 3 seconds, 1.0MPa in surface pressure, 7mm in width) in the MD (FIG. 12 c). In fig. 12c, the hatched portion S is a portion heat-sealed. Next, an aluminum plate AL (30 mm. times.52 mm, 3mm in thickness) as a dummy cell and 0.5g of water were sealed in the opening E which was not heat-sealed (FIG. 12 d). Then, the opening was heat-sealed (190 ℃, 3 seconds, 1.0MPa of surface pressure, 7mm width), and the pseudo battery and the water were sealed (FIG. 12 e). Next, the heat-sealed portion was cut into a width of 3mm (a position of a two-dot chain line in fig. 12e), and a test cell 12 formed in a box shape having an internal space (pressure 1atm) was produced (fig. 12 f). Next, as shown in fig. 13, the test cell was sandwiched between 2 stainless steel plates 20 and fixed by a fixing separator 21. In this case, the spacing W between the 2 stainless steel plates was 7.0 mm. Next, in this state, the test cell 12 was placed in an oven capable of reducing pressure, the pressure in the oven was set to 0atm, the temperature was increased to 120 ℃ at a temperature increase rate of 3 ℃/min, and the temperature at the time of unsealing was confirmed. The results are shown in Table 2. In the JIS standards, the oven temperature is used as a standard, but in the present example, the temperature of the sample is used as a standard for more detailed evaluation of the sealing property. The reason why the evacuation is performed is to assume that gas is generated inside the actual battery and the internal pressure is increased. The reason why the stainless steel plate and the fixing separator 21 are used is that the battery is usually fixed by a case or the like and excessively swells in order to suppress expansion of the battery.

(measurement of seal Strength)

According to JIS K7127: 1999, the sealing strength of the battery packaging material was measured at each measurement temperature of the 25 ℃ environment, the 80 ℃ environment, the 100 ℃ environment and the 120 ℃ environment, respectively, as follows. As a test piece, a battery packaging material cut into a long length with a TD width of 15mm was prepared. Specifically, as shown in fig. 14, each battery packaging material is first cut into 60mm (td) × 200mm (md) (fig. 14 a). Next, the battery packaging material is folded in two in the MD direction at the position of the fold P (middle of MD) so that the heat-fusible resin layers face each other (fig. 14 b). The heat-sealable resin layers were heat-sealed to each other at a sealing width of 7mm, a temperature of 190 ℃, a surface pressure of 1.0MPa, and a time of 3 seconds on the inner side in the MD direction from the fold P10mm (FIG. 14 c). In fig. 14c, the hatched portion S is a portion heat-sealed. Subsequently, a test piece was obtained by cutting in the MD direction (cutting at the position of the two-dot chain line in fig. 14 d) so that the width in the TD direction was 15mm (fig. 14 e). Next, the test piece 13 was left at each measurement temperature (25 ℃, 80 ℃, 100 ℃, 120 ℃) for 2 minutes, and the heat-fusible resin layer of the heat-fused portion was peeled off at a speed of 300 mm/minute by a tensile tester (AG-Xplus (trade name) manufactured by Shimadzu corporation) under an environment at each measurement temperature (25 ℃, 80 ℃, 100 ℃, 120 ℃) (FIG. 15). The maximum strength at the time of peeling was defined as the sealing strength (N/15 mm). The distance between the clamps was 50 mm. The results are shown in Table 2. In the measurement of the seal strength, there were a case where the test piece 13 peeled (broken) at the heat seal interface a shown in fig. 15 and a case where the test piece 13 broke at a portion different from the heat seal interface a (for example, at a position B in fig. 15). When the test piece 13 was broken, the breaking strength was shown in table 2 as the sealing strength (the numerical value of the band in table 2 is the breaking strength). The seal strength was an average value of 3 measurements.

[ Table 2]

As shown in table 2, the batteries using the packaging materials for batteries of examples 1 to 5 were not opened at a temperature of about 80 ℃ and were opened at a temperature of 120 ℃ or lower, which is a higher temperature, and were smoothly opened. On the other hand, in the battery using the battery packaging material of comparative example 13, the battery was not opened even if it exceeded 120 ℃.

Description of the symbols

1: substrate layer

2: adhesive layer

3: barrier layer

4: adhesive layer

4 a: setting position of probe

5: heat-fusible resin layer

6: surface coating layer

10: packaging material for battery

11: probe needle

12: battery for test

12 a: edge part

20: partition plate for fixing

21: stainless steel plate

Claims

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

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

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

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

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

the battery packaging material has a portion in which the heat-fusible resin layers are heat-fused to each other, and the sealing strength in an environment at 120 ℃ is 1/8 or less of the sealing strength in an environment at 25 ℃.

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

the battery packaging material has a sealing strength of 20N/15mm or less at 120 ℃ in a portion obtained by thermally bonding the thermally-adhesive resin layers to each other.

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

the substrate layer has at least one of a polyester film layer and a polyamide film layer.

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

the substrate layer at least comprises a polyester film layer and a polyamide film layer.

7. The packaging material for batteries according to claim 6, wherein:

the ratio of the thickness of the polyester film layer to the thickness of the polyamide film layer is in the range of 1: 1 to 1: 5.

8. The packaging material for batteries according to claim 6, wherein:

the substrate layer has the polyamide film layer and the polyester film layer in this order from the barrier layer side.

9. The packaging material for batteries according to claim 6, wherein:

between the polyester film layer and the polyamide film layer, a layer containing at least one of polyester and polyolefin is provided.

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

the resin constituting the adhesive layer contains a polyolefin skeleton.

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

the adhesive layer contains an acid-modified polyolefin.

12. The packaging material for a battery according to claim 11, wherein:

the acid-modified polyolefin of the adhesive layer is maleic anhydride-modified polypropylene,

the heat-fusible resin layer contains polypropylene.

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

the adhesive layer is a cured product of a resin composition containing at least 1 selected from a compound having an isocyanate group, a compound having an oxazoline group, and a compound having an epoxy group.

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

the adhesive layer is a cured product of a resin composition containing a curing agent having at least 1 selected from the group consisting of an oxygen atom, a heterocycle, a C ═ N bond, and a C — O — C bond.

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

the adhesive layer contains at least 1 selected from a polyurethane resin, an ester resin, and an epoxy resin.

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

the thickness of the adhesive layer is 5 μm or less.

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

the surface of the barrier layer is provided with an acid-resistant coating film,

when the acid-resistant coating film is analyzed by a time-of-flight secondary ion mass spectrometry, the acid-resistant coating film is detected to be derived from Ce₂PO₄ ⁺、CePO₄ ^-、CrPO₂ ⁺And CrPO₄ ^-Peak of at least 1 species.

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

the surface of the barrier layer has an acid-resistant coating film containing at least 1 selected from the group consisting of a phosphorus compound, a chromium compound, a fluoride compound, and a triazine thiol compound.

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

the barrier layer has an acid-resistant coating film containing a cerium compound on the surface thereof.

20. 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 19.

21. A method for manufacturing a battery packaging material, characterized in that:

comprises a step of laminating at least a base material layer, a barrier layer, an adhesive layer and a heat-fusible resin layer in this order to obtain a laminate,

22. A method for manufacturing a battery packaging material, characterized in that:

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

the substrate layer is composed of a polyester film layer.

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

the substrate layer at least comprises a polyester film layer,

the thickness of the polyester film layer is more than 10 mu m and less than 50 mu m.

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

the thickness of the adhesive layer is 10-40 μm.

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

the heat-fusible resin layer is formed of 2 or more layers.