JP2013222555A - Sheath material for lithium-ion battery and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheath material for a lithium-ion battery that has excellent chemical resistance, sealability, and moldability, and in which an adhesive resin layer and a sealant layer have a uniform thickness and are capable of obtaining stable characteristics, and a method of manufacturing the same.SOLUTION: A sheath material 1 for a lithium-ion battery is formed such that a base material layer 11, an adhesive layer 12, a metal foil layer 13, an anticorrosive treatment layer 14, an adhesive resin layer 15, and a sealant layer 16 are laminated in sequence and the adhesive resin layer 15 and sealant layer 16 are laminated separately by extrusion laminate. After being heated at a temperature equal to or higher than their melting temperatures, they are cooled at a temperature equal to or lower than their crystallization temperatures. A method of manufacturing the sheath material 1 for a lithium-ion battery includes: a first extrusion laminate step and a second extrusion laminate step in which the adhesive resin layer 15 and sealant layer 16 are formed separately; and post heat treatment step in which the adhesive resin layer 15 and sealant layer 16 are heated and cooled as mentioned above.

Description

  The present invention relates to a packaging material for a lithium ion battery and a method for producing the same.

  BACKGROUND ART Lithium ion batteries that can be ultra-thin and miniaturized have been actively developed as battery devices used in personal digital assistants such as personal computers and mobile phones, video cameras, satellites, vehicles, and the like. Lithium-ion battery exterior materials (hereinafter sometimes referred to simply as “exterior materials”) are lightweight, have high heat dissipation, and can be freely selected, unlike conventional metal cans. In view of this, a laminate-type exterior material made of a multilayer film (for example, a structure such as a base material layer / first adhesive layer / metal foil layer / second adhesive layer / sealant layer) has attracted attention. Such laminate-type exterior materials are roughly classified into two types depending on the type of the second adhesive layer between the metal foil layer and the sealant layer. That is, it is roughly classified into a dry laminate configuration using a thermosetting resin such as an adhesive for dry laminate for the second adhesive layer and a thermal laminate configuration using a thermoplastic material such as an acid-modified polyolefin resin for the second adhesive layer. The An exterior material having a dry laminate structure is widely used in consumer applications such as portable devices that require moldability and low cost. On the other hand, exterior materials having a heat laminate configuration are widely used in industrial applications such as electric vehicles, electric motorcycles, and electric bicycles that require higher reliability.

The lithium ion battery using a laminate-type exterior material is sealed with battery contents such as a positive electrode, a separator, a negative electrode, an electrolytic solution in which an electrolyte is dissolved, and a tab composed of a tab lead and a tab sealant. As forms, the following two types of packaging forms have been proposed.
(I) A pouch type in which a pouch-shaped container body is formed using an exterior material, and the battery contents are stored and sealed.
(Ii) An embossed type in which the exterior material is cold-molded to form a recess, and the battery contents are stored and sealed in the recess.
In the embossed type, in order to enclose the battery contents more efficiently, a form in which concave portions are formed on both sides of the exterior material to be bonded to increase the storage volume and the battery capacity is also adopted. For example, a lithium ion battery in which two exterior materials having recesses formed by cold molding are faced to each other, the battery contents are accommodated in these recesses, and the edge portions are heat sealed and sealed.

Laminate-type exterior materials are required to have various properties such as sealing properties, chemical resistance, moldability, water vapor barrier properties, heat resistance and cold resistance, and insulation properties. Among them, the metal foil layer depends on the battery contents. Is particularly required to have chemical resistance to suppress corrosion.
Specifically, since the metal can is sealed by laser welding, the penetration of moisture from the outside into the battery is sufficiently suppressed. On the other hand, the laminate-type exterior material is sealed by heat sealing that is thermocompression bonded at a temperature equal to or higher than the melting temperature of the sealant layer with the sealant layers facing each other. Since the moisture permeates through the second adhesive layer and the sealant layer, the heat-sealed edge portion gradually permeates through the second adhesive layer and the sealant layer between the metal foil layers from the side end surfaces, and the moisture enters the battery. When moisture enters the battery, it reacts with a fluorine-based electrolyte such as LiPF ₆ to generate hydrogen fluoride. Since this hydrogen fluoride which is an acid corrodes the surface of the metal foil layer, it reduces the adhesion between the second adhesive layer and the metal foil layer. Moreover, in the exterior material of a dry laminate structure, the adhesive forming the second adhesive layer is hydrolyzed, so that cohesive failure occurs easily in the second adhesive layer. Thus, the generation of hydrofluoric acid becomes a delamination factor in the vicinity of the second adhesive layer.

  Therefore, a corrosion prevention treatment layer is formed between the metal foil layer and the second adhesive layer. For example, a base material layer, a first adhesive layer, a corrosion prevention treatment layer, a metal foil layer, a corrosion prevention treatment layer, a second adhesion layer and a sealant layer are sequentially laminated, and the corrosion prevention treatment layer is a chemical conversion treatment. A packaging material is known which is a layer formed by treatment, the second adhesive layer is an adhesive resin layer formed of acid-modified polypropylene (PPa), and the sealant layer is a layer formed of polypropylene (PP). (Patent Document 1). In the exterior material, there is no possibility that the adhesive resin layer is hydrolyzed, and corrosion of the metal foil layer is suppressed by the corrosion prevention treatment layer, so that delamination on the adhesive resin layer side of the metal foil layer is suppressed. . Further, in order to enhance adhesion between the adhesive resin layer and the sealant layer and suppress delamination, the exterior material is formed using a co-extrusion laminating method. Specifically, PPa and PP are laminated on the corrosion prevention treatment layer formed on the metal foil layer by the coextrusion laminating method, laminated by the sandwich laminating method, and then heated at a temperature equal to or higher than the softening point of PPa and PP. The adhesive resin layer and the sealant layer are formed by processing.

JP 2001-202928 A

  However, the exterior material manufactured by the method of Patent Document 1 may not provide sufficient chemical resistance, sealing properties, and moldability. In addition, the thickness of the adhesive resin layer and the sealant layer may become uneven, and the characteristics of the exterior material may not be stable.

  The present invention provides an outer packaging material for a lithium ion battery that has excellent chemical resistance, sealing properties, and moldability, and has a uniform and stable thickness of an adhesive resin layer and a sealant layer, and the lithium ion battery It aims at providing the manufacturing method of the exterior material.

The present invention employs the following configuration in order to solve the above problems.
[1] A method for manufacturing a packaging material for a lithium ion battery, in which at least an adhesive layer, a metal foil layer, a corrosion prevention treatment layer, an adhesive resin layer, and a sealant layer are sequentially laminated on one surface side of a base material layer. ,
The step (X1) of forming the corrosion prevention treatment layer on the metal foil layer, and the step of laminating the base material layer via the adhesive layer on the opposite side of the corrosion prevention treatment layer of the metal foil layer (X2) and a step (X3) of laminating the sealant layer on the corrosion prevention treatment layer via the adhesive resin layer,
The step (X3)
A first extrusion laminating step of forming the adhesive resin layer by extrusion lamination on the corrosion prevention treatment layer;
A second extrusion laminating step of forming the sealant layer on the adhesive resin layer by extrusion lamination;
After the second extrusion laminating step, the adhesive resin layer and the sealant layer are heated at a temperature not lower than the melting temperature of the adhesive resin layer and not lower than the melting temperature of the sealant layer, and then not higher than the crystallization temperature of the adhesive resin layer. And a post-heat treatment step of cooling at a temperature lower than the crystallization temperature of the sealant layer.
[2] For the lithium ion battery according to [1], including an intermediate treatment step of performing a surface treatment on the adhesive resin layer or forming an intermediate coating layer on the adhesive resin layer after the first extrusion lamination step. A method for manufacturing an exterior material.
[3] The exterior material for a lithium ion battery according to [2], wherein the surface treatment is at least one selected from the group consisting of corona treatment, ozone treatment, flame treatment, ultraviolet irradiation treatment, excimer treatment, and plasma treatment. Manufacturing method.
[4] A coating liquid containing at least one selected from the group consisting of an inorganic oxide, a coupling agent, a polyolefin, an isocyanate compound, and polyethyleneimine is applied onto the adhesive resin layer to form the intermediate coating layer. The manufacturing method of the exterior material for lithium ion batteries as described in [2].
[5] The method for producing an exterior material for a lithium ion battery according to any one of [1] to [4], wherein the heating temperature in the post-heat treatment step is 140 to 220 ° C and the cooling temperature is 10 to 100 ° C.
[6] The method for manufacturing an exterior material for a lithium ion battery according to any one of [1] to [5], wherein the corrosion prevention treatment layer is formed by a non-chromium treatment.
[7] Between the first extrusion laminating step and the second extrusion laminating step, the adhesive resin layer is heated at a temperature equal to or higher than a melting temperature of the adhesive resin layer, and is equal to or lower than a crystallization temperature of the adhesive resin layer. The manufacturing method of the exterior material for lithium ion batteries in any one of [1]-[6] which has the intermediate heat treatment process cooled at temperature.
[8] A lithium ion battery exterior material in which at least an adhesive layer, a metal foil layer, a corrosion prevention treatment layer, an adhesive resin layer, and a sealant layer are sequentially laminated on one surface side of the base material layer,
After the adhesive resin layer and the sealant layer are separately laminated by extrusion lamination and heated at a temperature equal to or higher than the melting temperature of the adhesive resin layer and equal to or higher than the melting temperature of the sealant layer, the crystallization temperature of the adhesive resin layer An outer packaging material for a lithium ion battery, which is a layer formed by cooling at a temperature below the crystallization temperature of the sealant layer.
[9] The lithium ion according to [8], wherein a surface treatment is applied to the sealant layer side of the adhesive resin layer, or an intermediate coating layer is formed between the adhesive resin layer and the sealant layer. Battery exterior material.
[10] The exterior material for a lithium ion battery according to [9], wherein the surface treatment is at least one selected from the group consisting of corona treatment, ozone treatment, flame treatment, ultraviolet irradiation treatment, excimer treatment, and plasma treatment. .
[11] The intermediate coating layer is formed by coating a coating liquid containing at least one selected from the group consisting of an inorganic oxide, a coupling agent, a polyolefin, an isocyanate compound, and polyethyleneimine on the adhesive resin layer. The outer packaging material for a lithium ion battery according to [9], wherein the outer layer is a layer formed.

The outer packaging material for a lithium ion battery according to the present invention has excellent chemical resistance, sealing properties and moldability, and the adhesive resin layer and the sealant layer have uniform thickness and stable characteristics.
According to the method for manufacturing an outer packaging material for a lithium ion battery of the present invention, lithium ions having excellent chemical resistance, sealing properties, and moldability, and having uniform adhesive resin layer and sealant layer thickness and stable characteristics. A battery packaging material is obtained.

It is sectional drawing which showed an example of the exterior material for lithium ion batteries of this invention. It is sectional drawing which showed the other example of the exterior material for lithium ion batteries of this invention. It is sectional drawing which showed the other example of the exterior material for lithium ion batteries of this invention. It is the schematic which showed the manufacturing process of the exterior material for lithium ion batteries of this invention. It is the schematic which showed the manufacturing process of the exterior material for lithium ion batteries of this invention. It is the schematic which showed the manufacturing process of the exterior material for lithium ion batteries of this invention. It is the schematic which showed the manufacturing process of the exterior material for lithium ion batteries of this invention. It is the schematic which showed the manufacturing process of the exterior material for lithium ion batteries of this invention. It is the perspective view which showed the lithium ion battery using the exterior material for lithium ion batteries of this invention. It is the perspective view which showed a mode that the side edge part of the lithium ion battery of FIG. 9 was turned up. It is the perspective view which showed the manufacturing process of the lithium ion battery of FIG.

<Exterior materials for lithium-ion batteries>
Hereinafter, an example of the exterior material for a lithium ion battery of the present invention will be described with reference to FIG.
As shown in FIG. 1, an exterior material 1 for a lithium ion battery of the present embodiment (hereinafter referred to as “exterior material 1”) has an adhesive layer 12, a metal foil layer on one surface side of a base material layer 11. 13 is a laminate in which a corrosion prevention treatment layer 14, an adhesive resin layer 15, and a sealant layer 16 are sequentially laminated. The packaging material 1 is used so that the base material layer 11 is an outermost layer and the sealant layer 16 is an innermost layer.

(Base material layer 11)
The base material layer 11 is formed on the metal foil layer 13 via the adhesive layer 12. The base material layer 11 imparts heat resistance in a sealing process when manufacturing the battery, and plays a role of suppressing the generation of pinholes that can occur during molding and distribution. Moreover, it plays the role which suppresses the fracture | rupture of the metal foil layer 13 at the time of cold forming, or improves the insulation of the metal foil layer 13 and another metal member.
Examples of the base material layer 11 include stretched or unstretched films such as polyester resin, polyamide resin, and polyolefin resin. Of these, a biaxially stretched polyamide film and a biaxially stretched polyester film are preferable because they are excellent in moldability, heat resistance, puncture resistance, and insulation.

The film forming the base material layer 11 may be a single layer film having a single resin layer or a multilayer film having two or more resin layers, and two or more films may be dry laminated. It may be a composite film bonded with an adhesive.
The monolayer film is preferably a biaxially stretched polyamide film or a biaxially stretched polyester film. As the multilayer film, a biaxially stretched coextruded film having a multilayer structure of polyamide resin / polyester thermoplastic elastomer / polyester resin is preferable. The composite film is preferably a composite film in which a biaxially stretched polyamide film and a biaxially stretched polyester film are bonded together with a polyurethane adhesive.

Polyester thermoplastic elastomers are more resistant to hydrogen fluoride and electrolytes than polyurethane adhesives, and are less susceptible to degradation by these chemicals in battery manufacturing processes and the like. An axially stretched coextruded film is more preferred.
Examples of the polyester-based thermoplastic elastomer include Primalloy manufactured by Mitsubishi Chemical Corporation.

The base material layer 11 may have additives such as a flame retardant, a lubricant, an antiblocking agent, an antioxidant, a light stabilizer, a tackifier, and an antistatic agent dispersed therein or applied to the surface. Good.
Examples of the lubricant include fatty acid amides (for example, oleic acid amide, erucic acid amide, stearic acid amide, behenic acid amide, ethylene bisoleic acid amide, ethylene biserucic acid amide) and the like.
Examples of the anti-blocking agent include various filler-based anti-blocking agents such as silica. An additive may be used individually by 1 type and may use 2 or more types together.

The thickness of the base material layer 11 is preferably 6 to 50 μm, more preferably 10 to 40 μm, from the viewpoint of puncture resistance, insulation, moldability, and the like.
An uneven shape may be formed on the surface of the base material layer 11 in order to improve scratch resistance and slipperiness.

(Adhesive layer 12)
The adhesive layer 12 is formed between the base material layer 11 and the metal foil layer 13. The adhesive layer 12 not only has an adhesive force necessary to firmly bond the base material layer 11 and the metal foil layer 13, but also has a follow-up property to protect the metal foil layer 13 from breaking during cold forming. Is required.
As a material for the adhesive layer 12, a two-component curing type polyurethane adhesive in which an aromatic or aliphatic isocyanate is allowed to act as a curing agent on a main component such as polyester polyol, polyether polyol, acrylic polyol, and polyolefin polyol. Is preferred. 1-10 are preferable and, as for the molar ratio (NCO / OH) of the isocyanate group of the hardening | curing agent with respect to the hydroxyl group of the main ingredient of the said polyurethane-type adhesive agent, 2-5 are more preferable.

The adhesive layer 12 may be added with a thermoplastic elastomer, a tackifier, a filler, a pigment, a dye, or the like described in the adhesive resin layer 15.
The thickness of the adhesive layer 12 is preferably 1 to 10 μm, and more preferably 2 to 6 μm, from the viewpoint of adhesive strength, followability, and workability.

(Metal foil layer 13)
The metal foil layer 13 is provided in order to prevent moisture from entering the lithium ion battery. Further, the metal foil layer 13 is required to have excellent spreadability and enable deep drawing because of cold forming.
As the metal foil layer 13, various metal foils such as aluminum and stainless steel can be used, and aluminum foil is preferable from the viewpoints of mass (specific gravity), workability such as moisture resistance and spreadability, and cost.

As the aluminum foil, for example, a known soft aluminum foil can be used, and an aluminum foil containing iron is preferable from the viewpoint of pinhole resistance and spreadability at the time of molding. 0.1-9.0 mass% is preferable and, as for content of iron in aluminum foil (100 mass%), 0.5-2.0 mass% is more preferable. If the iron content is at least the lower limit, pinhole resistance and spreadability are improved. If the iron content is less than or equal to the upper limit, flexibility is improved.
The thickness of the metal foil layer 13 is preferably 10 to 100 μm and more preferably 15 to 80 μm from the viewpoint of barrier properties, pinhole resistance, and workability.

An untreated aluminum foil may be used for the metal foil layer 13, but an aluminum foil subjected to a degreasing treatment is preferable. The degreasing treatment is roughly classified into a wet type and a dry type.
Examples of the wet type degreasing treatment include acid degreasing and alkali degreasing. Examples of the acid used for acid degreasing include inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, and hydrofluoric acid. These acids may be used individually by 1 type, and may use 2 or more types together. Moreover, you may mix | blend various metal salts used as supply sources, such as an iron (III) ion and a cerium (III) ion, if the etching effect of aluminum foil improves. As an alkali used for alkali degreasing, sodium hydroxide etc. are mentioned as a thing with a high etching effect, for example. Moreover, what mix | blended weak alkali type and surfactant is mentioned. The wet type degreasing treatment is performed by an immersion method or a spray method.
Examples of the dry type degreasing treatment include a method of performing a degreasing treatment by increasing the treatment time in the step of annealing the aluminum foil. In addition to the degreasing treatment, frame treatment, corona treatment and the like can be mentioned. Furthermore, a degreasing process in which contaminants are oxidatively decomposed and removed by active oxygen generated by irradiation with ultraviolet rays having a specific wavelength may be employed.

(Corrosion prevention treatment layer 14)
The corrosion prevention treatment layer 14 is formed on the sealant layer 16 side of the metal foil layer 13. The corrosion prevention treatment layer 14 serves to prevent the surface of the metal foil layer 13 from being corroded by hydrogen fluoride generated by the reaction between the electrolyte and moisture. In addition, the metal foil layer 13 and the adhesive resin layer 15 are also firmly adhered to each other by the function as an anchor.
As the corrosion prevention treatment layer 14, for example, chromate treatment with a corrosion prevention treatment agent comprising chromate, phosphate, fluoride and various thermosetting resins, oxides that are rare earth elements (for example, cerium oxide, zircon oxide) Etc.), phosphate, and a layer formed by a ceria sol treatment with a corrosion prevention treatment agent composed of various thermosetting resins. Moreover, the corrosion prevention process layer 14 should just be a layer in which the corrosion resistance of the metal foil layer 13 is fully obtained, for example, the layer formed by the phosphate process, the boehmite process, etc. may be sufficient as it.
Since the use of hexavalent chromium leads to environmental destruction, the corrosion prevention treatment layer 14 is preferably a layer formed by non-chromium treatment that does not use chromium.

The corrosion prevention treatment layer 14 may be a single layer or a plurality of layers.
The thickness of the corrosion prevention treatment layer 14 is preferably 5 nm to 1 μm, more preferably 10 nm to 200 nm, from the viewpoint of the corrosion prevention function and the function as an anchor.

(Adhesive resin layer 15)
The adhesive resin layer 15 is formed between the sealant layer 16 and the corrosion prevention treatment layer 14. Examples of the adhesive resin layer 15 include a layer formed of a thermoplastic adhesive such as an acid-modified polyolefin resin. The acid-modified polyolefin resin can firmly adhere to both the sealant layer 16 and the corrosion prevention treatment layer 14. Moreover, since it is excellent in chemical resistance, even if hydrogen fluoride generated by the reaction between the electrolytic solution and moisture or the electrolytic solution is present, it is possible to suppress the adhesive resin layer 15 from decomposing and degrading to lower the adhesiveness.

The acid-modified polyolefin resin is a resin obtained by graft-modifying a polyolefin resin with an acid. The acid-modified polyolefin resin is preferably a maleic anhydride-modified polyolefin resin obtained by graft-modifying a polyolefin resin with maleic anhydride.
Examples of the polyolefin resin include low density, medium density, and high density polyethylene; homo, block, and random polypropylene. In addition, a copolymer obtained by copolymerizing polar molecules such as acrylic acid and methacrylic acid, a polymer such as cross-linked polyolefin, and the like can be used, and a resin subjected to dispersion, copolymerization, or the like can be employed. These polyolefin resins may be used individually by 1 type, and may use 2 or more types together.
As the acid-modified polyolefin resin, maleic anhydride-modified polypropylene is more preferable than maleic anhydride-modified polyethylene from the viewpoint of heat resistance.

The modification rate of maleic anhydride in the maleic anhydride-modified polypropylene is preferably 0.01 to 10% by mass, and more preferably 0.1 to 5% by mass. The modification rate is a mass ratio of a portion derived from maleic anhydride in maleic anhydride-modified polypropylene.
For the adhesive resin layer 15, one kind of acid-modified polyolefin resin may be used alone, or two or more kinds of acid-modified polyolefin resins may be used in combination.
Examples of commercially available thermoplastic adhesives include Admer manufactured by Mitsui Chemicals, Modic manufactured by Mitsubishi Chemical, and the like.

  The adhesive resin layer 15 may contain a soft resin. Thereby, the stretch whitening resistance due to cracks during cold forming is improved, the adhesion is improved by improving the wettability, and the properties such as film forming properties are improved by reducing the anisotropy. It is preferable that the soft resin is uniformly dispersed.

Examples of the soft resin include thermoplastic elastomers, and olefin elastomers and styrene elastomers are preferable.
Examples of olefin elastomers include ethylene / propylene copolymers, ethylene / 1-butene copolymers, ethylene / α-olefin copolymers, propylene / 1-butene copolymers, propylene / α-olefin copolymers. 1-butene / α-olefin copolymer, propylene / 1-butene / ethylene copolymer, propylene / α-olefin / ethylene copolymer, propylene / α-olefin / 1-butene copolymer, 1-butene -An alpha-olefin-ethylene copolymer etc. are mentioned.
Examples of the styrene elastomer include styrene / ethylene / butylene / styrene copolymers and styrene / ethylene / propylene / styrene copolymers.
These olefin elastomers and olefin elastomers may be used alone or in combination of two or more.

When using soft resin, 1-35 mass% is preferable and, as for content of soft resin in the adhesive resin layer 15, 5-30 mass% is more preferable.
Further, the dispersion diameter of the soft resin in the adhesive resin layer 15 is preferably 1 nm to 20 μm, and more preferably 10 nm to 10 μm. In the present invention, the dispersed diameter means the longest axis of the ellipsoid forming the dispersed phase.

  Commercially available soft resins include, for example, Asahi Kasei's Tuftec, Kuraray's Septon, Mitsui Chemical's Notio, Toughmer, Mitsubishi Chemical's Zelas, Thermoran, Sumitomo Chemical's Tufselen, Exelen, Esprene. , Espolex, Nippon Polypro's Wellnex, Newcon, Prime Polymer's Prime TPO, Sun Allomer's Catalloy, Qualia and the like.

The melt flow rate (MFR) of the material forming the adhesive resin layer 15 is preferably 3 to 30 g / 10 min under the conditions of a temperature of 230 ° C. and a load of 2.16 kgf.
The thickness of the adhesive resin layer 15 is preferably 2 to 50 μm.

(Sealant layer 16)
The sealant layer 16 is formed on the corrosion prevention treatment layer 14 via the adhesive resin layer 15. By laminating the sealant layer 16 on the adhesive resin layer 15, the sealant layers 16 of the two exterior materials face each other and heat sealed at the melting temperature or higher of the sealant layer 16, thereby sealing the lithium ion battery. You can stop. Further, by controlling the crystallinity of the sealant layer 16, it is possible to reduce the amount of moisture that enters the battery from the side end face of the heat-sealed edge portion. Moreover, the fluidity | liquidity of resin extruded from the edge part at the time of heat sealing can be adjusted by adjusting melt viscosity.

As a material of the sealant layer 16, a polyolefin resin is preferable. Examples of the polyolefin resin include the polyolefin resins mentioned in the description of the acid-modified polyolefin resin of the adhesive resin layer 15. A polyolefin resin may be used individually by 1 type, and may use 2 or more types together.
As the polyolefin resin, polypropylene is preferable to polyethylene from the viewpoint of heat resistance.
Examples of commercially available polyolefin resins include Novatec FL02A manufactured by Nippon Polypropylene, Prime Polypro F329RA manufactured by Prime Polymer, and Sun Allomer PH943B manufactured by Sun Allomer. Among these, Prime Polypro F329RA is preferable because it is excellent in moldability and hardly causes cracks in the sealant layer 16 during cold molding.

The sealant layer 16 may contain various additives such as a lubricant, an antiblocking agent, an antistatic agent, and a nucleating agent. These additives may be used individually by 1 type, and may use 2 or more types together.
The MFR of the material forming the sealant layer 16 is preferably 3 to 30 g / 10 min under the conditions of a temperature of 230 ° C. and a load of 2.16 kgf.
The thickness of the sealant layer 16 is preferably 10 to 80 μm.

Similar to the adhesive resin layer 15, a soft resin may be blended in the sealant layer 16. Thereby, the stretch whitening resistance due to cracks during cold forming is improved, the adhesion is improved by improving the wettability, and the properties such as film forming properties are improved by reducing the anisotropy. It is preferable that the soft resin is uniformly dispersed.
As a soft resin mix | blended with the sealant layer 16, the same thing as what was mentioned by the adhesive resin layer 15 is mentioned, for example, A preferable aspect is also the same.

When the soft resin is used, the content of the soft resin in the sealant layer 16 is preferably 1 to 35% by mass, and more preferably 5 to 30% by mass.
Further, the dispersion diameter of the soft resin in the sealant layer 16 is preferably 1 nm to 20 μm, and more preferably 10 nm to 10 μm.

The exterior material 1 includes an adhesive resin layer 15 and a sealant layer 16 that are separately laminated by extrusion lamination and heated at a temperature equal to or higher than the melting temperature of the adhesive resin layer 15 and equal to or higher than the melting temperature of the sealant layer 16. It is a layer formed by being cooled at a temperature not higher than 15 crystallization temperature and not higher than the crystallization temperature of the sealant layer 16. That is, the adhesive resin layer 15 and the sealant layer 16 are sequentially laminated by extrusion lamination, and after being heated at a temperature at which the adhesive resin layer 15 and the sealant layer 16 are melted together, the adhesive resin layer 15 and the sealant layer 16 are both crystallized. It is a layer formed by cooling at a temperature lower than or equal to the temperature at which it is heated. The melting temperature in the present invention means that in differential scanning calorimetry, the temperature is raised from 20 ° C. to 200 ° C. at 10 ° C./min, and then cooled to 20 ° C. at 50 ° C./min. It is a value measured as a peak temperature when the temperature is increased at a rate of 1 minute. Further, the crystallization temperature is a temperature at which an exothermic peak accompanying crystallization is obtained when it is melted at a melting temperature or higher and then slowly cooled at 25 ° C. in differential scanning calorimetry.
Since the adhesive resin layer 15 and the sealant layer 16 are formed as described above, they have excellent chemical resistance, sealing properties, and moldability, and the thickness of the adhesive resin layer 15 and the sealant layer 16 is high. The packaging material 1 having uniform and stable characteristics is obtained. The following factors can be considered as factors for obtaining the effect.

In a conventional exterior material such as Patent Document 1 in which an adhesive resin layer and a sealant layer are laminated by coextrusion lamination, the same type of polypropylene resin is used for the adhesive resin layer and the sealant layer. Since it is also dissolved, sufficient laminate strength can be obtained. On the other hand, the material of the corrosion prevention treatment layer and the adhesive resin layer are greatly different, and the laminate strength is lower than that of the interface between the adhesive resin layer and the sealant layer. In addition, after the laminate is formed by coextrusion lamination, the adhesive resin layer and the sealant layer are heated at a temperature equal to or higher than the softening point of the adhesive resin layer and the sealant layer, and the layers are formed. The resin is not fully dissolved. As a result, it is difficult to say that the resin forming the adhesive resin layer is sufficiently wet against the corrosion prevention treatment layer side of the metal foil layer, and only a part of the surface layer of the adhesive resin layer is corrosion resistant. It is considered that it is in close contact with the treatment layer. Therefore, it is difficult to obtain sufficient laminate strength and heat seal strength. When the adhesive resin layer and sealant layer are swollen by the electrolyte during long-term use of the exterior material, the laminate strength of the corrosion prevention treatment layer and the adhesive resin layer is greatly reduced. However, chemical resistance and sealing properties are considered to be reduced.
Further, when heated at a temperature equal to or higher than the softening point, the crystals in the adhesive resin layer and the sealant layer are partially dissolved, and the melted portion and the non-melted portion of the crystal are mixed. Therefore, during cooling, crystals grow uniformly in the melted part, while in the non-melted part, crystals grow around the remaining crystal nuclei, and the crystalline state becomes uneven in the adhesive resin layer and sealant layer, and cracks occur. Is likely to occur. If cracks occur in the adhesive resin layer and the sealant layer, whitening is likely to occur particularly in the stretched portion during cold molding, and the cracks become a movement path of lithium ions and cause deterioration of battery characteristics.
In the case of coextrusion lamination, the thickness of the adhesive resin layer and the sealant layer tends to be non-uniform, and the characteristics of the exterior material may not be sufficiently stable.

On the other hand, in the present invention, since the adhesive resin layer 15 and the sealant layer 16 are separately laminated by extrusion lamination, the thickness of the adhesive resin layer 15 and the sealant layer 16 becomes uniform, and the characteristics of the exterior material 1 are improved. Stabilize. Further, since the adhesive resin layer 15 and the sealant layer 16 are heated at a temperature equal to or higher than the melting temperature of the adhesive resin layer 15 and the sealant layer 16, the resin forming the adhesive resin layer 15 is sufficiently dissolved, and the corrosion prevention treatment layer is obtained. 14 and the adhesive resin layer 15 are increased in the laminate strength, and the heat seal strength is also increased.
Further, since the adhesive resin layer 15 and the sealant layer 16 are heated at a temperature equal to or higher than the melting temperature of the adhesive resin layer 15 and the sealant layer 16, crystals in the adhesive resin layer 15 and the sealant layer 16 are sufficiently dissolved and uniform. Crystal structure can be obtained. Moreover, since it cools at the temperature below the crystallization temperature of the adhesive resin layer 15 and the sealant layer 16 after a heating, it is suppressed that crystallization progresses too much and embrittles. For this reason, cracks are hardly generated in the adhesive resin layer and the sealant layer, and whitening and deterioration of battery characteristics during cold molding are suppressed.

The exterior material of the present invention is not limited to the exterior material 1 described above. For example, the exterior material of this invention may form a corrosion prevention process layer on both surfaces of a metal foil layer.
Moreover, the exterior material 2 for lithium ion batteries illustrated to FIG. 2 (henceforth "the exterior material 2") may be sufficient. The same parts as those of the exterior material 1 in the exterior material 2 are denoted by the same reference numerals, and description thereof is omitted.
As shown in FIG. 2, the exterior material 2 is formed by sequentially laminating an adhesive layer 12, a metal foil layer 13, a corrosion prevention treatment layer 14, an adhesive resin layer 15, and a sealant layer 16 on one surface side of the base material layer 11. In the laminated body, the outer coating layer 17 is laminated on the other surface side of the base material layer 11. That is, the exterior material 2 is the same as the exterior material 1 except that the outer coating layer 17 is formed outside the base material layer 11.

(Outer coating layer 17)
The outer coating layer 17 is formed on the surface of the base material layer 11 opposite to the metal foil layer 13 according to desired characteristics. By forming the outer coating layer 17, imparting scratch resistance that suppresses the occurrence of scratches on the base material layer 11 and chemical resistance that suppresses dissolution of the base material layer 11 by an electrolytic solution or the like. Can do. Moreover, moldability can also be improved by improving the slipperiness of the outermost surface or shaping the surface.

Examples of the outer coating layer 17 include olefin resin, acrylic resin, urethane resin, ester resin, epoxy resin, fluorine resin, silicon resin, alkyd resin, melamine resin, siloxane resin, amide resin, imide resin, cellulose resin, and acetic acid. Examples thereof include a layer formed by applying a coating liquid containing one or more selected from the group consisting of vinyl resins.
The outer coating layer 17 is dispersed with additives such as fillers, pigments, dyes, flame retardants, lubricants, antiblocking agents, antioxidants, light stabilizers, tackifiers, antistatic agents, or the like. You may apply to.
The thickness of the outer coating layer 17 is preferably 0.01 to 50 μm, and more preferably 0.1 to 30 μm, from the viewpoint of followability and workability.

Further, the exterior material of the present invention may be the exterior material 3 for a lithium ion battery illustrated in FIG. 3 (hereinafter referred to as “exterior material 3”). The same portions of the exterior material 3 as the exterior material 1 are denoted by the same reference numerals and description thereof is omitted.
As shown in FIG. 3, the exterior material 3 has an adhesive layer 12, a metal foil layer 13, a corrosion prevention treatment layer 14, an adhesive resin layer 15, an intermediate coating layer 18, and a sealant on one surface side of the base material layer 11. A layered body in which the layers 16 are sequentially stacked. That is, the exterior material 3 is the same as the exterior material 1 except that an intermediate coating layer 18 is formed between the adhesive resin layer 15 and the sealant layer 16.

(Intermediate coating layer 18)
By forming the intermediate coating layer 18, for example, water vapor barrier properties, electrical insulation properties, and the like can be improved.
Specifically, for example, the intermediate coating layer 18 is formed using an inorganic compound having a high barrier property or a thermoplastic resin having a high crystallinity, and the adhesive resin layer 15 is made thinner by the amount of the intermediate coating layer 18 formed. . Thereby, since the penetration | invasion of a water | moisture content is suppressed in the intermediate | middle coating layer 18, the amount of the water | moisture content permeating into the inside of a battery from the side end surface of the edge part heat-sealed can be reduced by the part which the intermediate | middle coating layer 18 formed.
In addition, if the intermediate coating layer 18 is formed using a thermosetting resin, the thickness of the intermediate coating layer 18 is difficult to change when a tab made of a tab lead and a tab sealant is sandwiched between the edge portions and heat sealed. The thickness of the edge portion is easily maintained. Thereby, it can suppress that a tab lead and the metal foil layer 13 contact and short-circuit, and can improve insulation.

The intermediate coating layer 18 was formed by coating a coating liquid containing at least one selected from the group consisting of an inorganic oxide, a coupling agent, a polyolefin, an isocyanate compound, and polyethyleneimine on the adhesive resin layer. Layer.
Examples of the inorganic oxide include silicon oxide and aluminum oxide. Examples of the coupling agent include a silane coupling agent and a titanium coupling agent. Examples of the polyolefin include polyethylene, polypropylene, acid-modified polypropylene, chlorinated polypropylene, acrylic-modified polypropylene, and polypropylene-based elastomer. These materials may be used alone or in combination of two or more.

In the intermediate coating layer 18, additives such as fillers, pigments, and tackifiers may be dispersed.
The thickness of the intermediate coating layer 18 is preferably 0.01 to 10 μm, and more preferably 0.1 to 5 μm, from the viewpoint of followability and workability.

Further, the exterior material of the present invention may be one in which a surface treatment is applied to the sealant layer 16 side of the adhesive resin layer 15. By adjusting the lamination strength of the adhesive resin layer 15 and the sealant layer 16 by the surface treatment, the heat seal strength when the edge portion of the exterior material is heat sealed and sealed can be increased.
The heat seal strength, which is the strength when the heat-sealed portions of the sealant layers of the exterior material are peeled, is composed of the burst strength in the initial peel and the seal strength in a region where the peel strength is stable after the initial peel. Specifically, the seal strength when peeling progresses along the interlayer between the adhesive resin layer 15 and the sealant layer 16 is smaller than the seal strength when peeling progresses in the adhesive resin layer 15, and the corrosion prevention treatment. The laminate strength of the adhesive resin layer 15 and the sealant layer 16 is adjusted so as to be greater than the seal strength when peeling between the layer 14 and the adhesive resin layer 15 proceeds.
When the adjustment of the laminate strength as described above is not performed, after the peeling occurs between the sealant layers, the generated crack advances to between the corrosion prevention treatment layer and the adhesive resin layer, and the peeling progresses along these layers. It's easy to do. This is because the sealing strength between the corrosion prevention treatment layer and the adhesive resin layer is lower than that in the adhesive resin layer or the sealant layer or between the adhesive resin layer and the sealant layer. However, if the adjustment of the laminate strength as described above is performed, after the crack progresses in the adhesive resin layer 15 and reaches between the corrosion prevention treatment layer 14 and the adhesion resin layer 15, the corrosion prevention treatment layer 14 and Releasing progresses along the interlayer between the adhesive resin layer 15 and the sealant layer 16 rather than progressing along the interlayer between the adhesive resin layers 15. The distance that the crack travels between the corrosion prevention treatment layer 14 and the adhesive resin layer 15 or between the adhesive resin layer 15 and the sealant layer 16 is longer than the distance that the crack travels within the adhesive resin layer 15. Therefore, it is more heat-induced as a whole to induce the separation to proceed between the corrosion prevention treatment layer 14 and the adhesive resin layer 15 having a higher seal strength than the seal strength between the corrosion prevention treatment layer 14 and the adhesive resin layer 15. The seal strength is increased.

  The surface treatment applied to the sealant layer 16 side of the adhesive resin layer 15 is preferably at least one selected from the group consisting of corona treatment, ozone treatment, flame treatment, ultraviolet irradiation treatment, excimer treatment, and plasma treatment.

<Method for manufacturing exterior material for lithium ion battery>
Hereinafter, as an example of a method for manufacturing the exterior material for a lithium ion battery, a method for manufacturing the exterior material 1 described above will be described.
The manufacturing method of the packaging material 1 includes the following steps (X1) to (X3).
(X1) A step of forming the corrosion prevention treatment layer 14 on the metal foil layer 13.
(X2) A step of laminating the base material layer 11 via the adhesive layer 12 on the opposite side of the metal foil layer 13 from the corrosion prevention treatment layer 14.
(X3) A step of laminating the sealant layer 16 on the corrosion prevention treatment layer 14 via the adhesive resin layer 15.

(Process (X1))
For example, a corrosion prevention treatment agent is applied to one surface of the metal foil layer 13 and baked to form the corrosion prevention treatment layer 14.
The coating method of the corrosion inhibitor is not particularly limited, and examples thereof include gravure coating, gravure reverse coating, roll coating, reverse roll coating, die coating, bar coating, kiss coating, and comma coating.

(Process (X2))
The base material layer 11 is bonded to the side of the metal foil layer 13 opposite to the side on which the corrosion prevention treatment layer 14 is formed, using an adhesive that forms the adhesive layer 12. Examples of the method for applying the adhesive include the same method as described in the step (X1).
Examples of the method for attaching the base material layer 11 include dry lamination, non-solvent lamination, wet lamination, and the like.
In the step (X2), an aging treatment may be performed in the range of room temperature to 100 ° C. to promote adhesion.

(Process (X3))
A sealant layer 16 is bonded onto the corrosion prevention treatment layer 14 via an adhesive resin layer 15. In this embodiment, the step (X3) includes the following first extrusion lamination step, second extrusion lamination step, and post heat treatment step.
First extrusion laminating step: a step of forming the adhesive resin layer 15 on the corrosion prevention treatment layer 14 by extrusion laminating.
Second extrusion laminating step: a step of forming the sealant layer 16 on the adhesive resin layer 15 by extrusion lamination.
Post-heat treatment step: After the second extrusion laminating step, the adhesive resin layer 15 and the sealant layer 16 are heated at a temperature equal to or higher than the melting temperature of the adhesive resin layer 15 and equal to or higher than the melting temperature of the sealant layer 16. A step of cooling at a temperature below the crystallization temperature and below the crystallization temperature of the sealant layer 16;

First extrusion lamination step and second extrusion lamination step:
As shown in FIG. 4, a laminate 20 composed of a base material layer 11, an adhesive layer 12, a metal foil layer 13, and a corrosion prevention treatment layer 14 is delivered from a delivery roll 41, and the corrosion prevention treatment layer 14 of the laminate 20. On top, the material forming the adhesive resin layer 15 is extruded from the extruder 42 and cooled while being pressed by the nip roll 43 and the cooling roll 44, and the base material layer 11, the adhesive layer 12, the metal foil layer 13, and the corrosion prevention treatment. A laminate 21 composed of the layer 14 and the adhesive resin layer 15 is obtained.
Furthermore, while conveying the laminated body 21 with the conveyance roll 45, the material which forms the sealant layer 16 is extruded from the extruder 46, it cools, pressing with the nip roll 47 and the cooling roll 48, and the base material layer 11, adhesive agent A laminate 22 composed of the layer 12, the metal foil layer 13, the corrosion prevention treatment layer 14, the adhesive resin layer 15, and the sealant layer 16 is wound around a winding roll 49.

  Thus, the method of separately forming the adhesive resin layer 15 and the sealant layer 16 in the first extrusion laminating step and the second extrusion laminating step is the characteristic of each resin material used for forming the adhesive resin layer 15 and the sealant layer 16. The extruder 42 and the extruder 46 are advantageous in that the extrusion temperature, the rotation speed, etc. can be set separately. In addition, in coextrusion, a wrapping phenomenon may occur due to the difference in fluidity of the two layers of molten resin, resulting in inconveniences such as non-uniform thickness and poor adhesion due to disordered interface between layers. However, these problems can be avoided and the quality is stabilized.

In the first extrusion laminating process and the second extruding laminating process, the surfaces of the resin materials extruded from the extruder 42 and the extruder 46 are solidified by air cooling, and the adhesive force of the adhesive resin layer 15 and the sealant layer 16 cannot be sufficiently obtained. . However, since the adhesive strength is increased in the post-heat treatment step described later, the adhesive strength to the extent that the adhesive resin layer 15 and the sealant layer 16 are temporarily attached can be obtained in the first extrusion lamination step and the second extrusion lamination step. That's fine.
In the first extrusion lamination process and the second extrusion lamination process, the surface of the resin material extruded from the extruder 42 and the extruder 46 may be subjected to ozone treatment. Thereby, the laminate strength of the corrosion prevention treatment layer 14 and the adhesive resin layer 15 and between the adhesive resin layer 15 and the sealant layer 16 is increased.

Post heat treatment process:
As shown in FIG. 5, the laminate 22 is sent out from the take-up roll 49, and the adhesive resin layer 15 and the sealant layer 16 are heated by the heating means 50 to a temperature equal to or higher than the melting temperature of the adhesive resin layer 15 and higher than the melting temperature of the sealant layer 16. After heating at the temperature, the adhesive resin layer 15 and the sealant layer 16 are cooled while being pressed by the nip roll 51 and the cooling roll 52 at a temperature below the crystallization temperature of the adhesive resin layer 15 and below the crystallization temperature of the sealant layer 16. The outer packaging material 1 is formed and wound on the winding roll 53.
Examples of the heating method by the heating means 50 include a method using a heat oven, a heat roll, or the like.

The heating temperature in the heating means 50 should just be the temperature more than the melting temperature of the adhesive resin layer 15 and the melting temperature of the sealant layer 16, 140-220 degreeC is preferable and 150-210 degreeC is more preferable.
If the heating temperature is equal to or higher than the lower limit value, the adhesive resin layer 15 is sufficiently dissolved, and the adhesive resin layer 15 is sufficiently wetted with respect to the corrosion prevention treatment layer 14 side of the metal foil layer 13 to prevent corrosion. The treatment layer 14 and the adhesive resin layer 15 are sufficiently adhered, the laminate strength is increased, and the heat seal strength when heat-sealed is also increased. Further, since the crystals in the adhesive resin layer 15 and the sealant layer 16 are sufficiently dissolved and are prevented from being separated into a melted portion and a non-melted portion, the crystals grow uniformly during cooling and cracks occur during cold forming. It becomes difficult to occur. Therefore, it is possible to suppress whitening of the adhesive resin layer 15 and the sealant layer 16 and deterioration of battery characteristics due to cracks serving as electrolyte migration paths. If the heating temperature is equal to or lower than the upper limit value, it is easy to suppress the base material layer 11 from being dissolved, and it is easy to maintain the mechanical properties of the base material layer 11.

The cooling temperature by the cooling roll 52 should just be the temperature below the crystallization temperature of the adhesive resin layer 15, and the crystallization temperature of the sealant layer 16, and 10-100 degreeC is preferable and 20-90 degreeC is more preferable.
When the cooling temperature is equal to or higher than the lower limit value, the cooling roll 52 is difficult to condense, and it is easy to suppress the appearance of the condensed water droplets from adhering to the surface of the sealant layer 16. If the cooling temperature is equal to or lower than the upper limit value, the progress of crystallization can be suppressed in the adhesive resin layer 15 and the sealant layer 16, so that the adhesive resin layer 15 and the sealant layer 16 become brittle and cracks are likely to occur. Easy to suppress.

It is preferable that the cooling at a temperature below the crystallization temperature of the adhesive resin layer 15 and below the crystallization temperature of the sealant layer 16 is before crystallization of the adhesive resin layer 15 and the sealant layer 16. That is, after the adhesive resin layer 15 and the sealant layer 16 are heated at a temperature equal to or higher than the melting temperature of the adhesive resin layer 15 and equal to or higher than the melting temperature of the sealant layer 16, the crystal below the crystallization temperature of the adhesive resin layer 15 and the crystal of the sealant layer 16. It is preferable to perform rapid cooling at a temperature below the conversion temperature. Thereby, a crystal structure (pseudo hexagonal crystal) excellent in flexibility and transparency is obtained, and resistance to stretching, folding, and the like during cold forming is increased.
“Before crystallization of the adhesive resin layer 15 and the sealant layer 16” means that, in the differential scanning calorimetry (DSC), after the adhesive resin layer 15 and the sealant layer 16 are melted at a temperature higher than their melting temperature, 25 ° C. It means before the exothermic peak accompanying crystallization is obtained when it is slowly cooled.

The packaging material 1 is obtained by the steps (X1) to (X3) described above.
In addition, the manufacturing method of the exterior material 1 is not limited to an above-described method. For example, you may perform a process (X2) after performing a process (X3). Further, as shown in FIG. 6, the laminate 22 may be continuously heated by the heating means 50 without being wound on the take-up roll 49 and cooled by the cooling roll 52. The same parts in FIG. 4 as FIG. 4 and FIG.

As a manufacturing method of the exterior material 2, for example, after the base material layer 11 is laminated on the outside of the metal foil layer 13 via the adhesive layer 12 in the step (X2), the outer coating layer 17 is formed on the base material layer 11. The method of applying and baking the coating liquid containing the resin material which forms can be mentioned.
As a coating method, the same method as the method quoted at the process (X1) is mentioned, for example.

As a manufacturing method of the exterior material 3, a coating liquid containing a material for forming the intermediate coating layer 18 is applied and baked between the first extrusion laminating process and the second extrusion laminating process to form the intermediate coating layer 18. Except for having an intermediate treatment step, the same method as the method for manufacturing the exterior material 1 described above can be used.
Specifically, for example, as shown in FIG. 7, the material for forming the adhesive resin layer 15 is extruded from the extruder 42 to the corrosion prevention treatment layer 14 side of the laminate 20 and is pressed by the nip roll 43 and the cooling roll 44. While cooling, a laminate 21 composed of the base material layer 11, the adhesive layer 12, the metal foil layer 13, the corrosion prevention treatment layer 14, and the adhesive resin layer 15 is obtained. After that, the material for forming the intermediate coating layer 18 is applied onto the adhesive resin layer 15 of the laminate 21 by the gravure roll 54 and the nip roll 55, and is heated and baked by the heating means 56 to form the base material layer 11 and the adhesive layer. 12, a laminate 23 composed of the metal foil layer 13, the corrosion prevention treatment layer 14, the adhesive resin layer 15 and the intermediate coating layer 18 is obtained. Further, the material for forming the sealant layer 16 is extruded from the extruder 46 onto the intermediate coating layer 18 of the laminate 23 and cooled while being pressed by the nip roll 47 and the cooling roll 48, so that the base material layer 11 and the adhesive layer 12. The laminate 24 composed of the metal foil layer 13, the corrosion prevention treatment layer 14, the adhesive resin layer 15, the intermediate coating layer 18, and the sealant layer 16 is wound around a winding roll 49.
The exterior material 3 is obtained by performing the post-heat treatment step described above on the laminate 24.
7 that are the same as those in FIG. 4 and FIG. As the heating means 56, for example, those mentioned in the heating means 50 can be cited.

Moreover, when surface-treating the sealant layer 16 side of the adhesive resin layer 15, an intermediate treatment step for performing surface treatment on the surface of the adhesive resin layer 15 between the first extrusion laminating step and the second extrusion laminating step is performed. What is necessary is just to provide.
Specifically, for example, as shown in FIG. 8, a material for forming the adhesive resin layer 15 is extruded from the extruder 42 to the corrosion prevention treatment layer 14 side of the laminate 20 and is pressed by a nip roll 43 and a cooling roll 44. While cooling, a laminate 21 composed of the base material layer 11, the adhesive layer 12, the metal foil layer 13, the corrosion prevention treatment layer 14, and the adhesive resin layer 15 is obtained. Thereafter, the surface treatment means 57 performs a surface treatment on the surface of the adhesive resin layer 15 and further extrudes the material for forming the sealant layer 16 from the extruder 46 while the laminate 21 is conveyed by the conveying roll 45, and the cooling with the nip roll 47. The laminate 22 composed of the base material layer 11, the adhesive layer 12, the metal foil layer 13, the corrosion prevention treatment layer 14, the adhesive resin layer 15, and the sealant layer 16 is cooled on the winding roll 49 while being pressurized by the roll 48. Wind up.
By performing the post-heat treatment step described above on the obtained laminate 22, an exterior material in which the surface treatment is applied to the sealant layer 16 side of the adhesive resin layer 15 is obtained. The surface treatment means 57 in this example is an apparatus that performs corona treatment including an electrode 58 and a dielectric roll 59.
In FIG. 8, the same parts as those in FIG. 4 and FIG.

Moreover, in the manufacturing method of the exterior material for lithium ion batteries of this invention, it is more than the melting temperature of the adhesive resin layer 15 between the 1st extrusion lamination process in a process (X3), and a 2nd extrusion lamination process. An intermediate heat treatment step of heating at a temperature of 5 ° C. and cooling at a temperature not higher than the crystallization temperature of the adhesive resin layer 15 may be included. Thereby, the wettability of the adhesive resin layer 15 with respect to the corrosion prevention treatment layer 14 side of the metal foil layer 13 is further improved, so that the laminate strength of the corrosion prevention treatment layer 14 and the adhesion resin layer 15 is further increased. The preferable aspect of the heating temperature and the cooling temperature in the intermediate heat treatment step is the same as the preferable aspect in the post heat treatment step.
Specifically, for example, heating means and cooling means similar to the heating means 50, the nip roll 51, and the cooling roll 52 are provided between the cooling by the cooling roll 44 and the extrusion by the extruder 46 in FIG. The aspect which heat-processes between an extrusion lamination process and a 2nd extrusion lamination process is mentioned.

The exterior material of the present invention can be used in various forms of lithium ion batteries. For example, as a lithium ion battery using the exterior material of the present invention, the lithium ion battery 100 illustrated in FIG. The lithium ion battery 100 includes a sealed container body 110 formed by the exterior material 1 and a battery member 112 that is accommodated in the container body 110 such that a part of the tab 114 protrudes to the outside.
The container body 110 has a first container part 110a and a second container part 110b in which the rectangular outer packaging material 1 is folded in two with the sealant layer 16 inside. By the inter-molding, a concave battery member accommodating portion 116 that protrudes from the sealant layer 16 side to the base material layer 11 side is provided, thereby forming a container shape. The tip edge portion 118 where the sealant layers 16 located on the opposite sides of the folded-back portion 110c in the first container portion 110a and the second container portion 110b are in contact with each other is heat-sealed with a part of the tab 114 sandwiched therebetween. Yes. Further, the side edge portions 120 and 122 on both sides of the battery member accommodating portion 116 are also heat sealed. The container body 110 is sealed by heat-sealing the front edge portion 118 and both side edge portions 120 and 122 in this way. In addition, the container body 110 is sealed in a state in which the electrolytic solution is accommodated together with the battery member 112 in the battery member accommodating portion 116.
Both side edge portions 120 and 122 are folded back toward the battery member housing portion 116 as shown in FIG.

  As shown in FIG. 9, the battery member 112 includes a battery member main body 124 having a positive electrode, a separator, and a negative electrode, and tabs 114 and 114 connected to the positive electrode and the negative electrode of the battery member main body 124, respectively. The tabs 114, 114 have leads 126, 126 joined to the positive electrode and the negative electrode, respectively, and tab sealants 128, 128 wound around the leads 126, 126 and welded to the sealant layer 16 of the tip edge portion 118. The tabs 114 and 114 are installed such that the base end side of the lead 126 is joined to the positive electrode and the negative electrode, respectively, and the tip end side is exposed to the outside of the container body 110.

The lithium ion battery 100 can be obtained by a manufacturing method having the following steps (Y1) to (Y4).
(Y1) The process of forming the battery member accommodating part 116 in the part used as the 1st container part 110a in the rectangular-shaped exterior material 1, as shown in FIG.
(Y2) The battery member 112 is disposed in the battery member housing portion 116 of the first container portion 110a, the portion that becomes the second container portion 110b of the exterior material 1 is folded back, and the tip edge portion 118 on the opposite side to the folded portion 110c is formed. Heat sealing so that a part of the tab 114 is exposed to the outside.
(Y3) The side edge portion 120 on one side of the battery member accommodating portion 116 is heat-sealed, and after the electrolyte is injected into the battery member accommodating portion 116 from the opening on the remaining side edge portion 122 side, the side remaining in a vacuum state Heat sealing the edge portion 122;
(Y4) A step of cutting and turning back a part of the side edge portions 120 and 122 on the side end side.

(Process (Y1))
From the sealant layer 16 side of the exterior material 1 to the base material layer 11 side, the battery member is cold-molded with a mold so as to have a desired molding depth in consideration of the rebound amount, and a battery member is formed in a portion that becomes the first container portion 110a. The accommodating part 116 is formed.
At the time of cold molding, for example, by using a lubricant or the like to reduce the friction coefficient of the surface of the exterior material 1, the friction between the mold and the exterior material 1 is reduced, and from the film press of the mold to the molded part. The exterior material 1 becomes easy to flow. Thereby, the deeper battery member accommodating part 116 can be formed, without producing a crack and a pinhole.

(Process (Y2))
The battery member 112 is accommodated in the battery member accommodating portion 116 formed in the step (Y1), the portion that becomes the second container portion 110b of the exterior material 1 is folded, and the tip edge portion 118 on the opposite side of the folded portion 110c is tabbed. Heat seal is performed so that a part of the plate 114 is exposed outside. At this time, the tab sealant 128 of the tab 114 is welded to both the sealant layer 16 on the first container part 110a side and the sealant layer 16 on the second container part 110b side in the exterior material 1.
The heat seal can be controlled by adjusting three conditions of the temperature of the heat seal bar, the surface pressure at the time of sealing, and the sealing time, at a temperature equal to or higher than the melting temperature of the adhesive resin layer 15 and the sealant layer 16, and at an appropriate pressure. This is done so that a molten resin reservoir called polysphere is not formed on the side end face of the edge portion.

(Process (Y3))
The side edge portion 120 on one side of the battery member housing portion 116 is heat-sealed, and an electrolyte solution in which an electrolyte is dissolved is injected into the battery member housing portion 116 from the remaining opening on the side edge portion 122 side. Then, after passing through a degassing step in aging, the side edge portion 122 remaining in a vacuum state is heat-sealed and sealed so that air does not enter the battery, whereby the lithium ion battery 100 is obtained.

(Process (Y4))
In many cases, since the resin forming the sealant layer 16 melted at the time of heat sealing protrudes from the side end surfaces of the side edge portions 120 and 122, a part of the side edge portions 120 and 122 on the side end surface side is predetermined. Cut away leaving a width. Thereafter, the side edge portions 120 and 122 are folded back toward the battery member housing portion 116 side.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by the following description.
[Materials used]
The materials used in this example are shown below.
(Base material layer 11)
Film A-1: Biaxially stretched coextruded film (thickness 25 μm) made of polyamide resin (nylon 6) / polyester thermoplastic elastomer (trade name “Primalloy AP”, manufactured by Mitsubishi Chemical Corporation) / polyester resin (polyethylene terephthalate) .
(Adhesive layer 12)
Adhesive B-1: A two-component curable polyurethane adhesive (thickness 4 μm).
(Metal foil layer 13)
Metal foil C-1: Soft aluminum foil (O8079 material, thickness 40 μm).
(Corrosion prevention treatment layer 14)
Treatment agent D-1: “Sodium polyphosphate-stabilized cerium oxide sol” adjusted to a solid content of 10% by mass using distilled water as a solvent. The phosphate was 10 parts by mass with respect to 100 parts by mass of cerium oxide.
Treatment agent D-2: 90% by mass of “polyacrylic acid ammonium salt (manufactured by Toagosei Co., Ltd.)” adjusted to a solid content concentration of 5% by mass using distilled water as a solvent, and “acrylic-isopropenyl oxazoline copolymer” (Nippon Shokubai Co., Ltd.) A composition comprising 10% by mass.
(Adhesive resin layer 15)
Adhesive resin E-1: Maleic anhydride-modified polypropylene (melting temperature 140 ° C., Bigat softening point 123 ° C., crystallization temperature 109 ° C., melt flow rate (230 ° C., 2.16 kgf) 5 g / 10 min).
(Sealant layer 16)
Sealant resin F-1: Polypropylene (melting temperature 137 ° C., bigat softening point 125 ° C., crystallization temperature 102 ° C., melt flow rate (230 ° C., 2.16 kgf) 20 g / 10 min).
(Intermediate coating layer 18)
Coating solution G-1: A coating solution obtained by dissolving maleic anhydride-modified polypropylene having a crystallinity of 57 in a mixed solution of toluene / methyl ethyl ketone (1: 1) so as to have a solid concentration of 18% by mass. The crystallinity is a value defined by the X-ray diffraction method.

[Example 1]
(Step (X1) and Step (X2))
On metal foil C-1, the processing agent D-1 was applied with a bar coater, and baked at 200 ° C. in a drying unit to form a cerium oxide layer having a dry thickness of 50 μm. Further, the treatment agent D-2 is applied onto the cerium oxide layer with a bar coater, and is baked at 150 ° C. in a drying unit to form an acrylic resin layer having a dry thickness of 50 nm. The cerium oxide layer and the acrylic resin The corrosion prevention processing layer 14 by which the layer was laminated | stacked was obtained. Next, after the film A-1 is bonded to the opposite side of the metal foil layer 13 from the corrosion prevention treatment layer 14 by the dry laminating method using the adhesive B-1, an aging treatment is performed at 40 ° C. for 7 days to produce heat. The base material layer 11 was laminated | stacked through the adhesive layer 12 (dry thickness 4 micrometers) through bridge | crosslinking. Film A-1 was laminated so that the polyamide resin side faced the metal foil layer 13 side to obtain a laminate 20.

(Process (X3))
First extrusion lamination step and second extrusion lamination step:
Next, as shown in FIG. 4, the adhesive resin E-1 is extruded at 250 ° C. from the extruder 42 to the corrosion prevention treatment layer 14 side of the laminate 20, and cooled by a cooling roll 44 at 20 ° C. to a thickness of 40 μm. The laminated resin 21 was obtained. Further, the sealant resin F-1 was extruded from the extruder 46 at 230 ° C., and cooled by a cooling roll 48 at 20 ° C. to form the sealant layer 16 having a thickness of 40 μm, whereby the laminate 22 was obtained.
Post heat treatment process:
Next, as shown in FIG. 5, the heating means 50 (heat oven) is heated at 190 ° C. which is equal to or higher than the melting temperature of the adhesive resin layer 15 and the sealant layer 16 to crystallize the adhesive resin layer 15 and the sealant layer 16. The exterior material 1 was obtained by cooling with a cooling roll 52 of 20 ° C. which is lower than the temperature while being pressurized before crystallization.

[Example 2]
In step (X3), as shown in FIG. 8, the same procedure as in Example 1 was performed except that corona treatment (50 W · min / m ² ) was performed between the first extrusion lamination step and the second extrusion lamination step. An exterior material was obtained.

[Example 3]
The laminated body 20 was obtained like the process (X1) and process (X2) of Example 1. Next, as shown in FIG. 7, the adhesive resin E-1 is extruded from the extruder 42 at 250 ° C. and cooled by a cooling roll 44 at 20 ° C. to form an adhesive resin layer 15 having a thickness of 36 μm. Got. Next, the coating liquid G-1 is applied onto the adhesive resin layer 15 of the laminate 21 by the gravure roll 54, baked at 180 ° C. in the heating means 56 (heat oven), and the intermediate coating layer 18 having a dry thickness of 4 μm. To obtain a laminate 23. Next, on the intermediate coating layer 18 of the laminate 23, the sealant resin F-1 is extruded from an extruder 46 at 230 ° C., and cooled by a cooling roll 48 at 20 ° C. to form a sealant layer 16 having a thickness of 40 μm. A laminate 24 was obtained. The laminate 24 was subjected to a post heat treatment step in the same manner as in Example 1 to obtain the exterior material 3.

[Example 4]
Between the first extrusion laminating process and the second extrusion laminating process, the adhesive resin layer 15 is heated at 190 ° C. which is higher than the melting temperature of the adhesive resin layer 15, and at 20 ° C. which is lower than the crystallization temperature of the adhesive resin layer 15. An exterior material was obtained in the same manner as in Example 1 except that an intermediate heat treatment step for cooling the adhesive resin layer 15 was performed.

[Comparative Example 1]
In the post heat treatment step, the adhesive resin layer 15 and the sealant layer 16 were heated at 130 ° C. above their bigat softening point and below the melting temperature, and cooled with a cooling roll at 20 ° C. below their crystallization temperature, An exterior material was obtained in the same manner as in Example 1.

[Comparative Example 2]
In the post-heat treatment step, the adhesive resin layer 15 and the sealant layer 16 were heated at 190 ° C. above their melting temperature and cooled by a 120 ° C. cooling roll exceeding their crystallization temperature, as in Example 1. Thus, an exterior material was obtained.

[Comparative Example 3]
In the same manner as in Example 1, the step (X1) and the step (X2) were performed to obtain the stacked body 20. Next, the adhesive resin E-1 and the sealant resin F-1 are extruded and laminated at 230 ° C. by a co-extrusion laminate on the corrosion prevention treatment layer 14 side of the laminate 20 at 20 ° C. It cooled by the cooling roll, and the laminated body of the base material layer / adhesive layer / metal foil layer / corrosion prevention treatment layer / adhesive resin layer / sealant layer was obtained. The post-heat treatment process was implemented with respect to the obtained laminated body like Example 1, and the exterior material was obtained.

[Evaluation method]
(Evaluation of chemical resistance)
An electrolytic solution in which ethylene carbonate, dimethyl carbonate and diethyl carbonate are mixed at a mass ratio of 1: 1: 1, LiPF ₆ is dissolved at 1 mol / L, and 1000 mass ppm of water is added to LiPF ₆ (85 C.), a sample cut out in a size of 100 mm × 150 mm from the exterior material obtained in each example was immersed and stored for 4 weeks. Thereafter, at 25 ° C., the laminate strength between the metal foil layer and the adhesive resin layer of the sample was measured by T-type peeling at a tensile rate of 100 mm / min. Further, the initial laminate strength before dipping in the electrolytic solution was measured in the same manner. Chemical resistance was evaluated according to the following criteria.
“◯ (good)”: The laminate strength after immersion is 10 N / 15 mm or more.
“X (defect)”: The laminate strength after immersion is less than 10 N / 15 mm.

(Evaluation of sealing performance)
The exterior material obtained in each example was cut into a size of 60 mm × 100 mm, the sample was folded back at the middle of the long side to 60 mm × 50 mm, and the edge of the 60 mm side was heat sealed with a width of 10 mm (temperature 190 ° C., surface pressure 0 0.5 MPa, sealing time 3 seconds). Thereafter, one of the edge portions of the 50 mm side is heat-sealed with a width of 5 mm under the same conditions as described above, and the same electrolyte as that used in the evaluation of chemical resistance is injected from the remaining one side, and the remaining 1 The edge portion of the side was sealed by heat sealing in the same manner as described above to obtain a pouch sample. After storing the pouch sample at 60 ° C. for 4 weeks, at 25 ° C., a heat-sealed strength is obtained by cutting a heat-sealed sample piece having a width of 15 mm × a length of 50 mm from the side of 60 mm, with a tensile speed of 100 mm / min, and T-type peeling. Was measured. The heat seal strength was also measured in the same manner for a sample piece cut out from a pouch sample into which no electrolyte was injected. The sealing property was evaluated according to the following criteria.
“◯ (good)”: The heat seal strength after injecting and storing the electrolyte is 100 N / 15 mm or more.
“X (defect)”: The heat seal strength after injecting and storing the electrolyte is less than 100 N / 15 mm.

(Evaluation of moldability)
The outer packaging material obtained in each example was cut into a size of 200 mm × 100 mm, and in the center of the sample, using a cold molding apparatus, a rectangular shape of 100 mm length × 50 mm width at a head speed of 10 mm / second was used. Cold molding of 5 mm was performed and the presence or absence of whitening was evaluated. The moldability was evaluated according to the following criteria.
“◯ (good)”: no whitening is observed in the stretched part.
“X (defect)”: Whitening is observed in a portion stretched by molding.

(Evaluation of water vapor barrier properties)
Sample pieces were cut out in a size of 240 mm × 70 mm from the exterior materials obtained in Examples 1 and 3, folded back at the center of the long side to 120 mm × 70 mm, and both sides of the 120 mm side were heat-sealed with a width of 3 mm (temperature 190 ° C. Surface pressure 0.5 MPa, sealing time 3 seconds). Ethylene carbonate, dimethyl carbonate, and diethyl carbonate were mixed at a mass ratio of 1: 1: 1, and 3 mg of an electrolytic solution having a water content of 20 mass ppm was injected from the remaining one side, and the remaining one side was the same as described above. Heat sealed with a width of 3 mm and sealed. The obtained sample was stored for 4 weeks in an environment of a temperature of 60 ° C. and a humidity of 90%, and then the amount of water contained in the electrolyte in the sample was measured with a Karl Fischer tester. Example in which the value obtained by subtracting the initial value (20 ppm by mass) from the measured value is the amount of moisture infiltrated from the side end face of the heat-sealed edge portion, and the case where the exterior material of Example 1 is used is 100 The amount of moisture in the case of using the exterior packaging material 3 was determined.

(Evaluation of thickness of adhesive resin layer and sealant layer)
About the exterior material obtained in each example, the cross-section (cut perpendicularly to the MD direction) of the center part and the end part in the TD direction is performed using a microtome, and the thickness of the adhesive resin layer and the sealant layer is measured with an optical microscope. It was measured. The thickness evaluation of the adhesive resin layer and the sealant layer was performed according to the following criteria.
“◯ (good)”: The film thickness difference between the adhesive resin layer and the sealant layer is within 10% between the center and the end.
“X (defect)”: The film thickness difference between the adhesive resin layer and the sealant layer exceeds 10% at the center and the end.

(Evaluation of characteristic stability)
For each sample piece cut out in a size of 100 mm × 150 mm from the center part and the end part in the TD direction in the packaging material of each example, the laminate strength between the metal foil layer and the adhesive resin layer is set to a tensile rate of 100 mm / min, T Measured by mold release. Moreover, the sample which carried out the heat sealing (temperature 190 degreeC, surface pressure 0.5MPa, sealing time 3 seconds) with the width | variety 10mm in the center part or edge part of the TD direction in the exterior material of each example was created, and from each sample A sample piece having a width of 15 mm and a length of 50 mm was cut out, and the heat seal strength was measured by T-type peeling at a tensile rate of 100 mm / min. Evaluation of characteristic stability was performed according to the following criteria.
“◯ (good)”: The difference in laminate strength and the difference in heat seal strength between the central portion and the end portion are both less than 5%.
“X (defect)”: Either the difference in laminate strength or the difference in heat seal strength between the center portion and the end portion is 5% or more.

(Comprehensive evaluation)
Comprehensive evaluation is "Good" for chemical resistance, sealing property, moldability, thickness evaluation and property stability evaluation, "Good", chemical resistance, sealing property, moldability In addition, any evaluation of “x” in any one of thickness evaluation and characteristic stability was defined as “x (defect)”.
Table 1 shows the evaluation results of chemical resistance, sealing properties, moldability, water vapor barrier properties, thickness evaluation, and characteristic stability in Examples 1 to 4 and Comparative Examples 1 to 3.

As shown in Table 1, in Examples 1 to 4 which are the exterior materials of the present invention, they have excellent chemical resistance, sealing properties and moldability, and the thicknesses of the adhesive resin layer and the sealant layer are uniform. The characteristics were stable. Moreover, the exterior material of Example 3 in which the intermediate coating layer was formed between the adhesive resin layer and the sealant layer was heat sealed compared to the exterior material of Example 1 having the same configuration except that the intermediate coating layer was not formed. The amount of moisture that entered from the side end face of the edge portion was small, and the water vapor barrier property was excellent.
On the other hand, in the post-heat treatment process, the exterior packaging material of Comparative Example 1 in which the adhesive resin layer and the sealant layer were heated at 130 ° C. above their bigat softening point and below the melting temperature had a laminate strength of 4 N / 15 mm after being immersed in the electrolyte. As a result, sufficient chemical resistance could not be obtained. This is considered to be because the adhesive resin layer is not sufficiently dissolved in the post-heat treatment step, and the adhesive resin layer is in close contact with the corrosion prevention treatment layer only at a part of the surface layer. Further, the heat seal strength was similarly reduced to 80 N / 15 mm, and sufficient sealing performance was not obtained. Moreover, when the peeling interface was confirmed, peeling in the exterior materials of Examples 1 to 4 was cohesive failure in the sealant layer, whereas in Comparative Example 1, the peeling between the corrosion prevention treatment layer and the adhesive resin layer was performed. It is considered that the decrease in the laminate strength affected the decrease in the heat seal strength. Moreover, in the exterior material of the comparative example 1, the whitening by the crack in an adhesive resin layer and a sealant layer was confirmed, and sufficient moldability was not obtained. This is presumably because the resin forming the adhesive resin layer and the sealant layer was not sufficiently dissolved in the post-heat treatment step, and a non-uniform crystal structure was formed, resulting in a density difference.
In the exterior material of Comparative Example 2, whitening due to cracks in the adhesive resin layer and the sealant layer was confirmed, and sufficient moldability was not obtained. This is presumably because the cooling temperature in the post-heat treatment step was higher than the crystallization temperature of the adhesive resin layer and the sealant layer, so that the adhesive resin layer and the sealant layer were not rapidly cooled and crystallization progressed too much.
In the exterior material of Comparative Example 3, since the adhesive resin layer and the sealant layer were formed by coextrusion, the thicknesses of the adhesive resin layer and the sealant layer were not uniform, and the characteristics were unstable. As described above, when the thickness of the adhesive resin layer and the sealant layer is not uniform, it is difficult to stabilize the characteristics of the exterior material.

  DESCRIPTION OF SYMBOLS 1-3 ... Exterior material for lithium ion batteries, 11 ... Base material layer, 12 ... Adhesive layer, 13 ... Metal foil layer, 14 ... Corrosion prevention processing layer, 15 ... Adhesive resin layer, 16 ... sealant layer, 17 ... outer coating layer, 18 ... intermediate coating layer.

Claims (11)

A method for producing an exterior material for a lithium ion battery in which at least an adhesive layer, a metal foil layer, a corrosion prevention treatment layer, an adhesive resin layer, and a sealant layer are sequentially laminated on one surface side of a base material layer,
The step (X1) of forming the corrosion prevention treatment layer on the metal foil layer, and the step of laminating the base material layer via the adhesive layer on the opposite side of the corrosion prevention treatment layer of the metal foil layer (X2) and a step (X3) of laminating the sealant layer on the corrosion prevention treatment layer via the adhesive resin layer,
The step (X3)
A first extrusion laminating step of forming the adhesive resin layer by extrusion lamination on the corrosion prevention treatment layer;
A second extrusion laminating step of forming the sealant layer on the adhesive resin layer by extrusion lamination;
After the second extrusion laminating step, the adhesive resin layer and the sealant layer are heated at a temperature not lower than the melting temperature of the adhesive resin layer and not lower than the melting temperature of the sealant layer, and then not higher than the crystallization temperature of the adhesive resin layer. And a post-heat treatment step of cooling at a temperature lower than the crystallization temperature of the sealant layer.   The exterior material for a lithium ion battery according to claim 1, further comprising an intermediate treatment step of performing a surface treatment on the adhesive resin layer or forming an intermediate coating layer on the adhesive resin layer after the first extrusion laminating step. Production method.   The manufacturing method of the exterior material for lithium ion batteries according to claim 2, wherein the surface treatment is at least one selected from the group consisting of corona treatment, ozone treatment, flame treatment, ultraviolet irradiation treatment, excimer treatment, and plasma treatment. .   The intermediate coating layer is formed by applying a coating liquid containing at least one selected from the group consisting of an inorganic oxide, a coupling agent, a polyolefin, an isocyanate compound, and polyethyleneimine on the adhesive resin layer. The manufacturing method of the exterior material for lithium ion batteries of 2.   The manufacturing method of the exterior material for lithium ion batteries as described in any one of Claims 1-4 whose heating temperature of the said post-heat-processing process is 140-220 degreeC, and whose cooling temperature is 10-100 degreeC.   The manufacturing method of the exterior material for lithium ion batteries as described in any one of Claims 1-5 which forms the said corrosion prevention process layer by a non-chromium-type process.   Between the first extrusion laminating step and the second extrusion laminating step, the adhesive resin layer is heated at a temperature not lower than the melting temperature of the adhesive resin layer and cooled at a temperature not higher than the crystallization temperature of the adhesive resin layer. The manufacturing method of the exterior material for lithium ion batteries as described in any one of Claims 1-6 which has the intermediate heat treatment process to do. A lithium ion battery exterior material in which at least an adhesive layer, a metal foil layer, a corrosion prevention treatment layer, an adhesive resin layer and a sealant layer are sequentially laminated on one surface side of the base material layer,
After the adhesive resin layer and the sealant layer are separately laminated by extrusion lamination and heated at a temperature equal to or higher than the melting temperature of the adhesive resin layer and equal to or higher than the melting temperature of the sealant layer, the crystallization temperature of the adhesive resin layer An outer packaging material for a lithium ion battery, which is a layer formed by cooling at a temperature below the crystallization temperature of the sealant layer.   The exterior for lithium ion batteries according to claim 8, wherein a surface treatment is applied to the sealant layer side of the adhesive resin layer, or an intermediate coating layer is formed between the adhesive resin layer and the sealant layer. Wood.   The exterior material for lithium ion batteries according to claim 9, wherein the surface treatment is at least one selected from the group consisting of corona treatment, ozone treatment, flame treatment, ultraviolet irradiation treatment, excimer treatment, and plasma treatment.   The intermediate coating layer is a layer formed by coating a coating liquid containing at least one selected from the group consisting of an inorganic oxide, a coupling agent, a polyolefin, an isocyanate compound, and polyethyleneimine on the adhesive resin layer. The outer packaging material for a lithium ion battery according to claim 9, wherein

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