JP2014049203A - Sheath material for lithium ion battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheath material for a lithium ion battery which is high in adhesion with a base material layer and has a base material protective layer to exhibit excellent scratch resistance in addition to sufficient moldability and electrolyte resistance.SOLUTION: A sheath material 1 for a lithium ion battery is formed by laminating a base material protective layer 18, a third adhesion layer 17, a base material layer 11, a first adhesion layer 12, a metal foil layer 13, an anti-corrosion treatment layer 14, a second adhesion layer 15 and a sealant layer 16 in this order from the outside. The base material protective layer 18 contains water-soluble polysaccharides (A) which are dissolved at 85°C by 1 pt.mass or more on the basis of 100 pts.mass of an alcohol aqueous solution containing water or alcohols, and the polymerization degree of the water-soluble polysaccharides (A) on the side opposite to the base material layer is higher than that of the water-soluble polysaccharides (A) on the side of the base material layer.

Description

  The present invention relates to a packaging material for a lithium ion battery.

  Since secondary batteries are indispensable for miniaturization due to miniaturization of portable devices, installation space limitations, and the like, lithium ion batteries having higher energy density than nickel metal hydride and lead storage batteries have attracted attention. As a lithium-ion battery exterior material (hereinafter sometimes referred to simply as “exterior material”), it is a multilayer film that is lighter, has higher heat dissipation than conventional metal cans, and can be handled at low cost. The outer packaging material is widely used. As such an exterior material, for example, an exterior material in which a base material layer / first adhesive layer / aluminum foil layer / corrosion prevention treatment layer / second adhesive layer / sealant layer for preventing corrosion due to hydrofluoric acid is sequentially laminated. Are known.

  As a lithium ion battery using the outer packaging material, for example, a concave portion is formed by cold molding in one part when the outer packaging material is folded in half, and a positive electrode, a separator, a negative electrode, an electrolytic solution, etc. are formed in the concave portion. It is known that the battery contents are placed, the remaining part is folded, and the edge part is heat sealed. In recent years, in order to efficiently store more battery contents and increase the energy density, lithium ion batteries in which recesses are formed on both sides of the exterior material to be bonded have also been manufactured.

  In order to increase the energy density of a lithium ion battery, it is important to deepen the recess formed by cold forming and increase the amount of battery contents accommodated in the recess. Therefore, a nylon film excellent in moldability is widely used for the base material layer. However, since the nylon film has low electrolyte solution resistance, if the electrolyte solution adheres to the base material layer during battery production or use, the base material layer may be dissolved and the aluminum foil layer may be corroded. In addition, since the nylon film has low scratch resistance, the surface of the base material layer may be damaged when handled, and the designability, durability, and the like may be reduced.

As an exterior material with improved resistance to electrolyte solution on the base material layer side, for example, on the outside of the base material layer made of nylon film, polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymer, maleic anhydride-modified polypropylene, polyester resin An exterior material in which at least one coating layer selected from the group consisting of an epoxy resin, a phenol resin, a fluororesin, a cellulose ester, a urethane resin and an acrylic resin is formed is known (Patent Document 1).
However, although the exterior material of Patent Document 1 provides sufficient electrolytic solution properties, it is difficult to obtain sufficient scratch resistance particularly for in-vehicle use.
Moreover, when forming the layer which protects a base material layer on the outer side of a base material layer, it is important to fully improve the adhesiveness of this layer and a base material layer.

Japanese Patent No. 3567229

  The present invention provides a packaging material for a lithium ion battery having a base material protective layer that has high adhesion to a base material layer and exhibits excellent scratch resistance in addition to sufficient moldability and electrolyte resistance.

The exterior material for a lithium ion battery of the present invention includes a base material layer made of a nylon film,
A first adhesive layer provided on the first surface side of the base material layer;
A metal foil layer provided on the opposite side of the base layer of the first adhesive layer;
A corrosion prevention treatment layer provided on the opposite side of the metal foil layer from the first adhesive layer;
A second adhesive layer provided on the opposite side of the corrosion prevention treatment layer from the metal foil layer;
A sealant layer provided on the opposite side of the corrosion prevention treatment layer of the second adhesive layer;
A third adhesive layer provided on the second surface side of the base material layer;
A base material protective layer provided on the side opposite to the base material layer of the third adhesive layer,
The base material protective layer contains the following water-soluble polysaccharide (A), and the degree of polymerization of the water-soluble polysaccharide (A) on the side opposite to the base material layer is the water-soluble polysaccharide (A) on the base material layer side. ) The degree of polymerization of the lithium ion battery exterior material is higher.
Water-soluble polysaccharide (A): At 85 ° C., at least one solvent selected from the group consisting of an aqueous alcohol solution containing 50% by mass of methanol, ethanol, propanol or isopropyl alcohol, and water, A polysaccharide that dissolves 1 part by mass or more per part.

Moreover, the exterior material for a lithium ion battery of the present invention includes a base material layer made of a nylon film,
A first adhesive layer provided on the first surface side of the base material layer;
A metal foil layer provided on the opposite side of the base layer of the first adhesive layer;
A corrosion prevention treatment layer provided on the opposite side of the metal foil layer from the first adhesive layer;
A second adhesive layer provided on the opposite side of the corrosion prevention treatment layer from the metal foil layer;
A sealant layer provided on the opposite side of the corrosion prevention treatment layer of the second adhesive layer;
A base material protective layer provided on the second surface side of the base material layer,
The base material protective layer contains the water-soluble polysaccharide (A) and the adhesive resin (B), and the degree of polymerization of the water-soluble polysaccharide (A) opposite to the base material layer is the base material layer side. The degree of polymerization of the water-soluble polysaccharide (A) is higher.

  The adhesive resin (B) is preferably at least one selected from the group consisting of polyvinyl resins, polyolefin resins, urethane resins, epoxy resins, acrylic resins, and polyester resins.

  The outer packaging material for a lithium ion battery of the present invention has a high adhesion to the base material layer, and has a base material protective layer that exhibits excellent scratch resistance in addition to sufficient moldability and electrolyte resistance. .

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.

<First Embodiment>
Hereinafter, an example of the outer packaging material for a lithium ion battery of the present invention will be shown and described in detail.
As shown in FIG. 1, the lithium ion battery exterior material 1 (hereinafter simply referred to as “exterior material 1”) of the present embodiment is disposed on the base layer 11 and the first surface 11 a side of the base layer 11. The first adhesive layer 12 provided, the metal foil layer 13 provided on the opposite side of the base layer 11 of the first adhesive layer 12, and the first adhesive layer 12 provided on the opposite side of the metal foil layer 13 Corrosion prevention treatment layer 14, second adhesive layer 15 provided on the opposite side of corrosion prevention treatment layer 14 to metal foil layer 13, and sealant provided on the opposite side of corrosion prevention treatment layer 14 of second adhesion layer 15. A layer 16, a third adhesive layer 17 provided on the second surface 11b side of the base material layer 11, a base material protective layer 18 provided on the opposite side of the third adhesive layer 17 from the base material layer 11, Have That is, the exterior material 1 includes a base material protective layer 18, a third adhesive layer 17, a base material layer 11, a first adhesive layer 12, a metal foil layer 13, a corrosion prevention treatment layer 14, a second adhesive layer 15, and a sealant layer 16. Is a laminated body laminated in this order.
When the exterior material 1 is used for a battery, the base material protective layer 18 is used as the outside, and the sealant layer 16 is used as the inside.

(Base material protective layer)
The base material protective layer 18 protects the base material layer 11 and plays a role of suppressing the base material layer 11 from being deteriorated or damaged by the electrolytic solution.
The base material protective layer 18 contains the following water-soluble polysaccharide (A).
Water-soluble polysaccharide (A): At 85 ° C., at least one solvent selected from the group consisting of an aqueous alcohol solution containing 50% by mass of methanol, ethanol, propanol or isopropyl alcohol, and water, A polysaccharide that dissolves 1 part by mass or more per part.
That is, the water-soluble polysaccharide (A) comprises at least one of methanol water having a concentration of 50% by mass, ethanol water having a concentration of 50% by mass, propanol water having a concentration of 50% by mass, isopropyl alcohol water having a concentration of 50% by mass, and water. It is a polysaccharide that dissolves in one ratio in the above ratio.
In the present invention, the dissolution of the polysaccharide includes not only the dissolved state in which the polysaccharide is completely molecularly dispersed but also the fact that the polysaccharide is swollen or dispersed to show a uniform dissolved state.

Examples of the water-soluble polysaccharide (A) include cellulose derivatives such as chitin and carboxymethylcellulose, chitin derivatives such as chitosan, amylose, amylopectin, dextran, pullulan, erucinane, sodium alginate, agar, pectin, tamarind gum, and xanthan gum. Can be mentioned.
A water-soluble polysaccharide (A) may be used individually by 1 type, and may use 2 or more types together.

The water-soluble polysaccharide (A) is particularly preferably cellulose having a regular structural arrangement and having a rigid skeleton by formation of intramolecular hydrogen bonds or intermolecular hydrogen bonds. Cellulose is known to have an extremely low linear expansion coefficient, and excellent moldability can be obtained due to the low linear expansion coefficient. Examples of the cellulose raw material include wood pulp, non-wood pulp, cotton, and bacterial cellulose. The fiber width of cellulose is preferably 2 nm or more and 200 nm or less. The length of cellulose is preferably 0.5 μm or more and 50 μm or less. If the fiber width and length of cellulose are within the above ranges, a uniform and transparent cellulose aqueous dispersion can be prepared. In addition, about the fiber width and length of a cellulose, about 0.001 mass% aqueous dispersion is cast on glass or mica, and it dries, and uses a transmission electron microscope (TEM) or an atomic force microscope (AFM). It can be obtained by observing.
The aqueous dispersion of cellulose used for forming the base material protective layer 18 is obtained by subjecting cellulose to mechanical treatment in water and making it finer. The mechanical treatment is not particularly limited, and examples thereof include treatment using a mixer, a high-pressure homogenizer, an ultrasonic homogenizer, grinder grinding, freeze grinding, media mill, and the like. Moreover, you may chemically-process a cellulose as a pre-process which performs a mechanical process.

  More preferably, the cellulose is crystalline cellulose. When the crystallinity of cellulose is high, the high modulus of elasticity of the base material protective layer 18 is maintained, and the electrolytic solution resistance and heat resistance are improved. As a method for obtaining an aqueous dispersion of highly crystalline cellulose, TEMPO oxidized cellulose obtained by chemically treating cellulose using 2,2,6,6-tetramethyl-1-pipedinyloxy radical (TEMPO) as a catalyst is used. A method is mentioned. An aqueous dispersion of TEMPO-oxidized cellulose has a feature that the pigment dispersibility is good when a pigment is added. Furthermore, since the aqueous dispersion of TEMPO-oxidized cellulose has high transparency of the dispersion, excellent design properties can be obtained. In addition, the aqueous dispersion of TEMPO-oxidized cellulose is excellent in coatability.

TEMPO oxidized cellulose is obtained, for example, by the chemical treatment shown below.
A nitroxy radical and sodium bromide (bromide) are added to cellulose dispersed in water, and an aqueous solution of sodium hypochlorite (oxidant) is added with stirring at room temperature to oxidize the cellulose. An alkaline solution such as sodium hydroxide is added during the oxidation reaction to control the pH in the reaction system to 9-11. At this time, the hydroxyl group at the C6 position on the surface of the cellulose fiber is oxidized to a carboxyl group, and TEMPO oxidized cellulose is obtained. After the treatment, it is sufficiently washed with water, and the obtained TEMPO-oxidized cellulose is dispersed in water in a fibrous form, and the solid content concentration is appropriately adjusted, which can be used as a constituent material of the aqueous dispersion.
As the oxidizing agent, hypohalous acid or a salt thereof, halogenous acid or a salt thereof can be used, and sodium hypochlorite is preferable.
Examples of the bromide include lithium bromide, potassium bromide, sodium bromide and the like, and sodium bromide is preferable.

The degree of polymerization of the water-soluble polysaccharide (A) is preferably from 100 to 800, more preferably from 250 to 400. If the degree of polymerization of the water-soluble polysaccharide (A) is at least the lower limit value, the scratch resistance becomes better. When the degree of polymerization of the water-soluble polysaccharide (A) is not more than the upper limit value, the adhesion between the base material layer 11 and the base material protective layer 18 becomes better.
The degree of polymerization of the water-soluble polysaccharide (A) is measured by a viscosity method using a copper ethylenediamine solution.

In the base material protective layer 18, the degree of polymerization of the water-soluble polysaccharide (A) on the side opposite to the base material layer 11 is higher than the degree of polymerization of the water-soluble polysaccharide (A) on the base material layer 11 side. . Thereby, both the particularly excellent adhesion between the substrate protective layer 18 and the substrate layer 11 and the particularly excellent scratch resistance can be achieved.
The base material protective layer 18 in which the degree of polymerization of the water-soluble polysaccharide (A) on the opposite side of the base material layer 11 is higher than the degree of polymerization of the water-soluble polysaccharide (A) on the base material layer 11 side is, for example, Preparing a plurality of coating liquids containing different water-soluble polysaccharides (A), and coating and drying these coating liquids in order from the coating liquid containing water-soluble polysaccharides (A) having a low degree of polymerization. Can be formed. The substrate protective layer 18 may be two layers or three or more layers.
For example, a layer containing a water-soluble polysaccharide (A) having a polymerization degree of 300, a layer containing a water-soluble polysaccharide (A) having a polymerization degree of 500, and a layer containing a water-soluble polysaccharide (A) having a polymerization degree of 700 May be a multi-layer base material protective layer 18 or the like laminated in order from the base material layer 11.

The base material protective layer 18 preferably contains a lubricant or is applied to the surface. Thereby, the moldability and winding yield of the exterior material 1 are improved. When the base material protective layer 18 contains a lubricant, it is preferable that the base material protective layer 18 contains a lubricant on the side opposite to the base material layer 11.
Examples of the lubricant include fatty acid amides (eg, oleic acid amide, erucic acid amide, stearic acid amide, behenic acid amide, ethylene bisoleic acid amide, ethylene biserucic acid amide), glycerin and the like.
One type of lubricant may be used alone, or two or more types may be used in combination.

The base material protective layer 18 may contain a plasticizer. Thereby, the moldability of the exterior material 1 improves. Examples of the plasticizer include phthalic acid plasticizers and glycol plasticizers.
Examples of the phthalic acid plasticizer include dioctyl phthalate, dimethyl phthalate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate, diisobutyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate, didodecyl phthalate, butyl benzyl phthalate, dimethyl glycol phthalate, ethyl phthalate Examples include ruethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, and diisodecyl glycolate.
Examples of the glycol plasticizer include ethylene glycol, diethylene glycol, triethylene glycol, hexamethylene glycol, polyethylene glycol, butyl phthalyl glycolate, triethylene glycol-2-ethyl butyrate, and glycerin. Of these, glycerin is preferred as the glycol plasticizer.
In addition, sugar alcohols such as sorbitol and xylitol and their compounds can also be used as plasticizers.

  The base material protective layer 18 preferably contains one or more elastomer components selected from the group consisting of olefin elastomers, styrene elastomers, and polyester elastomers. Thereby, the moldability of the exterior material 1 improves. The elastomer component is a component composed of a hard segment and a soft segment. When the substrate protective layer 18 contains an elastomer component, the elastomer component is preferably contained uniformly in the substrate protective layer 18.

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.
Examples of the hard segment of the polyester elastomer include crystalline polyesters such as polybutylene terephthalate, polybutylene naphthalate and polyethylene terephthalate, and polybutylene terephthalate is particularly preferable. Examples of the soft segment of the polyester elastomer include polyoxyalkylene glycols such as polytetramethylene glycol or polyesters such as polycaprolactone and polybutylene adipate, and polytetramethylene glycol is particularly preferable.
An elastomer component may be used individually by 1 type, and may use 2 or more types together.

The base material protective layer 18 preferably contains one or more filler components selected from the group consisting of organic fillers and inorganic fillers. Thereby, the scratch resistance of the base material protective layer 18 is improved. When making the base material protective layer 18 contain a filler component, it is preferable that the filler component is contained on the side of the base material protective layer 18 opposite to the base material layer 11.
As the organic filler, for example, plastic powder or fine particles can be used. Examples of the plastic include acrylic, polyethylene, polystyrene, polycarbonate, vinyl chloride, vinylidene chloride, and melamine.
Examples of the inorganic filler include fine particles such as carbon, silica, glass beads, glass powder, aluminum silicate, clay, zinc oxide, calcium carbonate, boron nitride, and mica.

The substrate protective layer 18 preferably contains a pigment in terms of design. When a pigment is used, the pigment may be contained in any layer outside the metal foil layer 13. However, since the pigment dispersibility is excellent and the color tends to be uniform, the pigment is added to the base material protective layer 18. It is preferable to contain.
The pigment is not particularly limited as long as the adhesion between the base material protective layer 18 and the base material layer 11 is not impaired, and may be an organic pigment or an inorganic pigment.
Examples of organic pigments include azo, phthalocyanine, quinacridone, anthraquinone, dioxazine, indigothioindigo, perinone-perylene, and isoindolenin.
Examples of inorganic pigments include carbon black, titanium oxide, cadmium, lead, and oxide oxide. Mica (mica) fine powder, fish scale foil, and the like may also be used.

From the viewpoint of water resistance, the base material protective layer 18 preferably has a crosslinked structure formed by a crosslinking agent.
Examples of the crosslinking agent include oxazoline, divinyl sulfone, carbodiimide, dihydrazine, dihydrazide, epichlorohydrin and the like. The said crosslinking agent may be used individually by 1 type, and may use 2 or more types together.
Moreover, the base material protective layer 18 may contain additives such as a flame retardant, an antiblocking agent, an antioxidant, a light stabilizer, a tackifier, and an antistatic agent in addition to those described above.

  In view of obtaining excellent electrolytic solution resistance and scratch resistance, the content of the water-soluble polysaccharide (A) in the base material protective layer 18 (100% by mass) is preferably 20% by mass or more, more preferably 40% by mass or more. Is more preferable. Moreover, the upper limit of content of the water-soluble polysaccharide (A) in the base-material protective layer 18 (100 mass%) is 100 mass%. The content of the water-soluble polysaccharide (A) is preferably 95% by mass or less, and more preferably 90% by mass or less from the viewpoint that the effects of other components can be easily obtained.

  When making the base material protective layer 18 contain a lubricant, 0.1-10 mass% is preferable and, as for content of the lubricant in the base material protective layer 18 (100 mass%), 1-5 mass% is more preferable. If content of the said lubricant is more than a lower limit, moldability will become more favorable. If content of the said lubricant is below an upper limit, it will suppress that a lubricant bleeds to the base material layer 11 side of the base material protective layer 18, and the adhesiveness of the base material layer 11 and the base material protective layer 18 falls. Cheap.

  When making the base material protective layer 18 contain a plasticizer, 1-70 mass% is preferable and, as for content of the plasticizer in the base material protective layer 18 (100 mass%), 10-60 mass% is more preferable. If content of the said plasticizer is more than a lower limit, moldability will become more favorable. If content of the said plasticizer is below an upper limit, heat resistance will become more favorable.

  When the base material protective layer 18 contains an elastomer component, the content of the elastomer component in the base material protective layer 18 (100% by mass) is preferably 5 to 80% by mass, and more preferably 10 to 70% by mass. If content of the said elastomer component is more than a lower limit, moldability will become more favorable. When the content of the elastomer component is not more than the upper limit value, the scratch resistance and the electrolytic solution resistance become better.

  When making the base-material protective layer 18 contain a filler component, 0.1-50 mass% is preferable and, as for content of the filler component in the base-material protective layer 18 (100 mass%), 1-30 mass% is more preferable. . If content of the said filler component is more than a lower limit, scratch resistance will become more favorable. If content of the said filler component is below an upper limit, moldability will become more favorable.

  When making the base material protective layer 18 contain a pigment, 0.1-30 mass% is preferable and, as for content of the pigment in the base material protective layer 18 (100 mass%), 5-20 mass% is more preferable. If content of the said pigment is in the said range, design property will become more favorable.

  0.1-5.0 micrometers is preferable and, as for the thickness of the base material protective layer 18, 0.3-3.0 micrometers is more preferable. If the thickness of the base material protective layer 18 is equal to or more than the lower limit value, the electrolytic solution resistance and the scratch resistance become better. If the thickness of the base material protective layer 18 is not more than the upper limit value, the moldability becomes better.

(3rd adhesive layer)
The third adhesive layer 17 is a layer that bonds the base material layer 11 and the base material protective layer 18 together. By adhering the base material layer 11 and the base material protective layer 18 through the third adhesive layer 17, the adhesion, moldability, and tensile strength between the base material layer 11 and the base material protective layer 18 are improved.
Examples of the third adhesive layer 17 include a layer formed by applying a coating solution containing the following adhesive resin (B).
Adhesive resin (B): At least one adhesive resin selected from the group consisting of polyvinyl resins, polyolefin resins, urethane resins, epoxy resins, acrylic resins and polyester resins.
As the adhesive resin (B), polyvinyl resins and polyester resins are preferable, polyvinyl alcohol, ethylene / vinyl acetate copolymer and polybutylene terephthalate are more preferable, and polyvinyl alcohol is particularly preferable.

  Further, the third adhesive layer 17 may be formed of a urethane-based adhesive described later in the section of the first adhesive layer 12, or may be formed of an adhesive component having a thermal laminate configuration described later in the section of the second adhesive layer 15. Also good.

The third adhesive layer 17 may contain additives such as fillers, pigments, dyes, flame retardants, lubricants, antiblocking agents, antioxidants, light stabilizers, tackifiers, and antistatic agents.
The thickness of the third adhesive layer 17 is preferably 0.1 to 5.0 μm, more preferably 1.0 to 4.0 μm from the viewpoint of adhesive strength.
3.0-10.0 micrometers is preferable and, as for the total thickness of the 3rd contact bonding layer 17 and the base-material protective layer 18, 2.0-6.0 micrometers is more preferable.

(Base material layer)
The base material layer 11 is a layer made of a nylon film.
The nylon film may be a stretched film or an unstretched film. Examples of the nylon forming the nylon film include nylon 6, nylon 11, nylon 12, nylon 66, nylon 610, nylon 612, and the like.
The second surface 11b of the base material layer 11 is preferably subjected to surface treatment such as corona treatment or plasma treatment. That is, the nylon film forming the base material layer 11 is preferably subjected to a surface treatment such as corona treatment or plasma treatment on the surface on which the base material protective layer 18 is provided. Thereby, the adhesiveness of the base material layer 11 and the base material protective layer 18 becomes better.

6-40 micrometers is preferable and, as for the thickness of the base material layer 11, 10-30 micrometers is more preferable. If the thickness of the base material layer 11 is equal to or more than the lower limit value, the pinhole resistance and the insulation are improved. If the thickness of the base material layer 11 is not more than the upper limit value, the moldability becomes better.
A coupling agent may be coated on the surface of the base material layer 11 on the first adhesive layer 12 side in order to help improve the adhesive strength.

(First adhesive layer)
The first adhesive layer 12 is a layer that bonds the base material layer 11 and the metal foil layer 13 together.
As an adhesive component constituting the first adhesive layer 12, a two-component curable type in which a bifunctional or higher functional aromatic or aliphatic isocyanate compound is allowed to act as a curing agent on a main component such as polyester polyol, polyether polyol, and acrylic polyol. The urethane adhesive is preferable.
For example, the urethane-based adhesive is aged at 40 ° C. for 4 days or more after coating, whereby the reaction of the hydroxyl group of the main agent and the isocyanate group of the curing agent proceeds to enable strong adhesion.
The thickness of the first adhesive layer 12 is preferably 1 to 10 μm, more preferably 3 to 7 μm, from the viewpoint of adhesive strength, followability, and workability.

(Metal foil layer)
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 viewpoint of workability such as moisture resistance and spreadability and cost. A general soft aluminum foil can be used as the aluminum foil. Among these, an aluminum foil containing iron is preferable from the viewpoint of excellent pinhole resistance and extensibility during molding.
0.1-9.0 mass% is preferable and, as for content of iron in the aluminum foil (100 mass%) containing iron, 0.5-2.0 mass% is more preferable. When the iron content is 0.1% by mass or more, the exterior material 1 is excellent in pinhole resistance and spreadability. If the iron content is 9.0% by mass or less, the exterior material 1 is excellent in flexibility.
The thickness of the metal foil layer 13 is preferably 9 to 200 μm, more preferably 15 to 100 μm, from the viewpoint of barrier properties, pinhole resistance, and workability.

(Corrosion prevention treatment layer)
The corrosion prevention treatment layer 14 serves to suppress the corrosion of the metal foil layer 13 due to the electrolytic solution or hydrofluoric acid generated by the reaction between the electrolytic solution and moisture. A lithium salt such as LiPF ₆ or LiBF ₄ used for an electrolyte of a lithium ion battery generates hydrofluoric acid by a hydrolysis reaction with moisture. By providing the corrosion prevention treatment layer 14, the inner side of the metal foil layer 13 is also prevented from being corroded by hydrofluoric acid, and delamination inside the metal foil layer can be suppressed. The corrosion prevention treatment layer 14 also plays a role of increasing the adhesion between the metal foil layer 13 and the second adhesive layer 15.
The corrosion prevention treatment layer 14 is preferably a coating film formed by a coating type or immersion type acid-resistant corrosion prevention treatment agent. The said coating film is excellent in the corrosion prevention effect with respect to the acid of the metal foil layer 13. FIG. Moreover, since the adhesive force of the metal foil layer 13 and the 2nd contact bonding layer 15 is strengthened by an anchor effect, the outstanding tolerance with respect to contents, such as electrolyte solution, is acquired.

As the coating film, for example, a coating film, chromate, phosphate, fluoride, and various thermosettings formed by a ceriazol treatment with a corrosion preventing treatment agent composed of cerium oxide, phosphate and various thermosetting resins. For example, a coating film formed by chromate treatment with a corrosion-inhibiting treatment agent made of a conductive resin.
The corrosion prevention treatment layer 14 is not limited to the coating film as long as the corrosion resistance of the metal foil layer 13 is sufficiently obtained. For example, a coating film formed by phosphate treatment, boehmite treatment, or the like may be used.

The corrosion prevention treatment layer 14 may be a single layer or a plurality of layers. In addition, an additive such as a silane coupling agent may be added to the corrosion prevention treatment layer 14.
The thickness of the corrosion prevention treatment layer 14 is preferably 10 nm to 5 μm, and more preferably 20 to 500 nm from the viewpoint of the corrosion prevention function and the function as an anchor.

(Second adhesive layer)
The second adhesive layer 15 is a layer that bonds the metal foil layer 13 on which the corrosion prevention treatment layer 14 is formed and the sealant layer 16. The packaging material 1 is roughly divided into a thermal laminate configuration and a dry laminate configuration depending on the adhesive component forming the second adhesive layer 15.
As an adhesive component for forming the second adhesive layer 15 in the thermal laminate configuration, an acid-modified polyolefin resin obtained by graft-modifying a polyolefin resin with an acid such as maleic anhydride is preferable. Since the acid-modified polyolefin-based resin has a polar group introduced into a part of the non-polar polyolefin-based resin, the sealant layer 16 is formed of a non-polar polyolefin-based resin film or the like, and the corrosion prevention treatment layer 14 is formed. When the coating film has polarity, it can be firmly adhered to both of them. In addition, by using acid-modified polyolefin resin, resistance to contents such as electrolyte solution is improved, and even if hydrofluoric acid is generated inside the battery, a decrease in adhesion due to deterioration of the second adhesive layer 15 is prevented. Cheap.
The acid-modified polyolefin resin used for the second adhesive layer 15 may be one type or two or more types.

Examples of the polyolefin resin used for the acid-modified polyolefin resin include low density, medium density or high density polyethylene; ethylene / α-olefin copolymer; homo, block or random polypropylene; propylene / α-olefin copolymer. Etc. In addition, a copolymer obtained by copolymerizing polar molecules such as acrylic acid and methacrylic acid with the above-described one, a polymer such as a crosslinked polyolefin, and the like can be used.
Examples of the acid that modifies the polyolefin-based resin include carboxylic acid, epoxy compound, acid anhydride, and the like, and maleic anhydride is particularly preferable.

As an adhesive component constituting the second adhesive layer 15 of the heat laminate structure, the polyolefin resin is made of maleic anhydride from the viewpoint that it is easy to maintain the adhesion between the sealant layer 16 and the metal foil layer 13 even if the electrolyte solution penetrates. A graft-modified maleic anhydride-modified polyolefin resin is preferable, and maleic anhydride-modified polypropylene is particularly preferable.
The modification rate of maleic anhydride-modified polypropylene with maleic anhydride (the mass of the portion derived from maleic anhydride relative to the total mass of maleic anhydride-modified polypropylene) is preferably 0.1 to 20% by mass, and 0.3 to 5% by mass. % Is more preferable.

  It is preferable that the second adhesive layer 15 having a heat laminate structure contains the elastomer component described in the base material protective layer 18. Thereby, it is easy to suppress that the second adhesive layer 15 is cracked and whitened at the time of cold forming, and it can be expected to improve adhesion by improving wettability, and improve film forming property by reducing anisotropy. . The elastomer component is preferably dispersed and compatible with each other in the order of nanometers in the acid-modified polyolefin resin.

The second adhesive layer 15 having a heat laminate structure can be formed by extruding the adhesive component with an extrusion device.
The melt flow rate (MFR) of the adhesive component of the second adhesive layer 15 having a heat laminate structure is preferably 4 to 30 g / 10 min under the conditions of 230 ° C. and 2.16 kgf.
As for the thickness of the 2nd contact bonding layer 15 of a heat lamination structure, 2-50 micrometers is preferable.

Examples of the adhesive component of the second adhesive layer 15 having a dry laminate structure include a two-component curable polyurethane adhesive similar to that described for the first adhesive layer 12.
Since the second adhesive layer 15 having a dry laminate structure has a hydrolyzable bonding portion such as an ester group or a urethane group, the second adhesive layer having a heat laminate structure is required for applications that require higher reliability. 15 is preferred.

(Sealant layer)
The sealant layer 16 is a layer that imparts sealing properties by heat sealing in the exterior material 1.
Examples of the sealant layer 16 include a polyolefin resin or a resin film made of an acid-modified polyolefin resin obtained by graft-modifying an acid such as maleic anhydride to a polyolefin resin.
Examples of the polyolefin resin include low-density, medium-density or high-density polyethylene; ethylene / α-olefin copolymer; homo, block, or random polypropylene; propylene / α-olefin copolymer. These polyolefin resin may be used individually by 1 type, and may use 2 or more types together.
Examples of the acid-modified polyolefin-based resin include the same as those mentioned in the second adhesive layer 15.

  The sealant layer 16 may be a single layer film or a multilayer film, and may be selected according to a required function. For example, in terms of imparting moisture resistance, a multilayer film in which a resin such as an ethylene / cyclic olefin copolymer or polymethylpentene is interposed can be used.

When a film formed by extrusion molding is used as the sealant layer 16, molecules tend to be oriented in the extrusion direction of the film. You may mix | blend the demonstrated elastomer component. This makes it difficult for the sealant layer 16 to be whitened when the exterior material 1 is cold-molded to form a recess.
The sealant layer 16 may be blended with various additives such as a flame retardant, a lubricant, an antiblocking agent, an antioxidant, a light stabilizer, and a tackifier.
10-100 micrometers is preferable and, as for the thickness of the sealant layer 16, 20-60 micrometers is more preferable.

  The exterior material 1 may be one in which the sealant layer 16 is laminated by dry lamination, but from the viewpoint of improving adhesion, the second adhesive layer 15 is made of an acid-modified polyolefin resin, and the sealant layer 16 is laminated by sandwich lamination. It is preferable that

(Production method)
Hereinafter, the manufacturing method of the exterior material 1 is demonstrated. However, the manufacturing method of the exterior material 1 is not limited to the following method. As a manufacturing method of the exterior material 1, the method which has the following process (X1)-(X4) is mentioned, for example.
(X1) A step of forming a corrosion prevention treatment layer 14 on the metal foil layer 13.
(X2) A step of laminating the base material layer 11 via the first adhesive layer 12 on the side opposite to the side on which the corrosion prevention treatment layer 14 is formed in the metal foil layer 13.
(X3) The process of laminating | stacking the base material protective layer 18 through the 3rd contact bonding layer 17 on the opposite side to the 1st contact bonding layer 12 of the base material layer 11. FIG.
(X4) A step of laminating the sealant layer 16 on the corrosion prevention treatment layer 14 side of the metal foil layer 13 via the second adhesive layer 15.

Step (X1):
For example, a corrosion prevention treatment agent is applied to one surface of the metal foil layer 13 and dried to form the corrosion prevention treatment layer 14. Examples of the anti-corrosion treatment agent include the above-described anti-corrosion treatment agent for ceriazole treatment, anti-corrosion treatment agent for chromate treatment, and the like.
The coating method of the corrosion inhibitor is not particularly limited, and various methods such as gravure coating, reverse coating, roll coating, and bar coating can be employed.

Step (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 first adhesive layer 12 by a technique such as dry lamination.
In the step (X2), an aging treatment may be performed in the range of room temperature to 100 ° C. in order to promote adhesion.

Step (X3):
For example, on the opposite side of the base material layer 11 from the first adhesive layer 12, a coating liquid containing the adhesive resin (B) and components such as additives to be used as necessary is applied and dried to form a third adhesive layer 17 is further applied, and a coating liquid containing a water-soluble polysaccharide (A) and, if necessary, a lubricant, an elastomer component, and the like is applied and dried to form the substrate protective layer 18. At this time, the base material protective layer 18 prepares, for example, a plurality of coating liquids containing water-soluble polysaccharides (A) having different degrees of polymerization, and these coating liquids are converted into water-soluble polysaccharides (A) having a low degree of polymerization. ) In the order of the coating liquid containing, and can be formed by drying.

  1-60 mass% is preferable and, as for the solid content concentration of the coating liquid which forms the 3rd contact bonding layer 17, 5-20 mass% is more preferable. If the solid content concentration is at least the lower limit, drying after coating becomes easy. When the solid content concentration is not more than the upper limit value, the coatability becomes better.

As the coating liquid for forming the base material protective layer 18, for example, an aqueous dispersion of a water-soluble polysaccharide (A) can be used. The aqueous dispersion of the water-soluble polysaccharide (A) may contain alcohols.
0.5-20 mass% is preferable and, as for the solid content concentration of the coating liquid which forms the base-material protective layer 18, 1-10 mass% is more preferable. If the solid content concentration is at least the lower limit, drying after coating becomes easy. When the solid content concentration is not more than the upper limit value, the coatability becomes better.

  Further, after forming the third adhesive layer 17 using the same adhesive as the adhesive forming the first adhesive layer 12, the base material protective layer 18 may be formed in the same manner as described above. Alternatively, the base material protective layer 18 may be formed in the same manner as described above after the third adhesive layer 17 is formed by an extrusion laminating method using an adhesive component that forms the second adhesive layer 15.

Step (X4):
In the case of a dry laminate configuration, for example, the same adhesive as that used to form the first adhesive layer 12 is used, and dry lamination, non-solvent lamination, wet lamination is provided on the side opposite to the metal foil layer 13 in the corrosion prevention treatment layer 14. The sealant layer 16 is bonded through the second adhesive layer 15 by a method such as the above.
In the case of the thermal laminate configuration, in the dry process, for example, the second adhesive layer 15 is formed by extrusion lamination on the opposite side of the corrosion prevention treatment layer 14 from the metal foil layer 13 using an adhesive component for thermal lamination, and sandwiched. The sealant layer 16 is laminated by lamination.
In the wet process, an adhesive resin liquid in which an adhesive component for heat laminating is dispersed in a solvent is applied to the side opposite to the metal foil layer 13 in the corrosion prevention treatment layer 14, and the solvent is removed at a temperature equal to or higher than the melting point of the adhesive component. After volatilizing and melting and softening the adhesive component, the sealant layer 16 is laminated on the second adhesive layer 15 by heat treatment such as thermal lamination.

The packaging material 1 is obtained by the steps (X1) to (X4) described above.
In addition, the manufacturing method of the exterior material 1 is not limited to the method of implementing the said process (X1)-(X4) sequentially. For example, the step (X1) may be performed after performing the step (X2). Further, the step (X3) may be performed after performing the step (X4).

  The exterior material 1 is provided with a base material protective layer 18 containing the water-soluble polysaccharide (A) on the outside of the base material layer 11 via the third adhesive layer 17. In addition to the resistance to electrolyte, it has excellent scratch resistance that can be used for in-vehicle use. Moreover, in the base material protective layer 18, the polymerization degree of the water-soluble polysaccharide (A) on the opposite side to the base material layer 11 is higher than the polymerization degree of the water-soluble polysaccharide (A) on the base material layer 11 side. Therefore, it is possible to express particularly excellent scratch resistance while obtaining excellent adhesion between the substrate layer 11 and the substrate protective layer 18.

Second Embodiment
Hereinafter, other embodiment of the exterior material of this invention is described based on FIG. In FIG. 2, the same parts as those in FIG.
The lithium ion battery exterior material 2 (hereinafter referred to as “exterior material 2”) of the present embodiment is provided on the base layer 11 and the first surface 11a side of the base layer 11 as shown in FIG. The first adhesive layer 12 formed, the metal foil layer 13 provided on the opposite side of the substrate layer 11 of the first adhesive layer 12, and the corrosion provided on the opposite side of the metal foil layer 13 from the first adhesive layer 12 The prevention treatment layer 14, the second adhesive layer 15 provided on the opposite side of the corrosion prevention treatment layer 14 from the metal foil layer 13, and the sealant layer provided on the second adhesion layer 15 opposite to the corrosion prevention treatment layer 14. 16 and a base material protective layer 19 provided on the second surface 11b side of the base material layer 11. That is, the exterior material 2 has a base material protective layer 19, a base material layer 11, a first adhesive layer 12, a metal foil layer 13, a corrosion prevention treatment layer 14, a second adhesive layer 15, and a sealant layer 16 laminated in this order. It is a laminate.
The packaging material 2 is used with the base material protective layer 19 on the outside and the sealant layer 16 on the inside.

(Base material protective layer)
The base material protective layer 19 is a layer containing the water-soluble polysaccharide (A) and the adhesive resin (B). Since the base material protective layer 19 contains the water-soluble polysaccharide (A), excellent electrolytic solution resistance and scratch resistance can be obtained, and the base material layer 11 may be deteriorated or damaged by the electrolytic solution. It is suppressed. Moreover, it is excellent in the adhesiveness of the base material layer 11 and the base material protective layer 19, a moldability, and tensile strength because the base material protective layer 19 contains adhesive resin (B).
The preferred water-soluble polysaccharide (A) and adhesive resin (B) are the same as in the first embodiment.

In the base material protective layer 19, the polymerization degree of the water-soluble polysaccharide (A) on the side opposite to the base material layer 11 is higher than the polymerization degree of the water-soluble polysaccharide (A) on the base material layer 11 side. Thereby, both the particularly excellent adhesion between the base material protective layer 19 and the base material layer 11 and the particularly excellent scratch resistance can be achieved.
The base material protective layer 19 has a higher degree of polymerization of the water-soluble polysaccharide (A) on the side opposite to the base material layer 11 than the degree of polymerization of the water-soluble polysaccharide (A) on the base material layer 11 side. Preparing a plurality of coating liquids containing different water-soluble polysaccharides (A), and coating and drying these coating liquids in order from the coating liquid containing water-soluble polysaccharides (A) having a low degree of polymerization. Can be formed. The base material protective layer 19 may be two layers or three or more layers.
For example, a layer containing a water-soluble polysaccharide (A) having a polymerization degree of 150, a layer containing a water-soluble polysaccharide (A) having a polymerization degree of 300, and a layer containing a water-soluble polysaccharide (A) having a polymerization degree of 500 May be a multilayer base material protective layer 19 or the like laminated in order from the base material layer 11.

Preferred combinations of the water-soluble polysaccharide (A) and the adhesive resin (B) include the following. These combinations of the water-soluble polysaccharide (A) and the adhesive resin (B) are excellent in compatibility and can better express each other's performance.
A combination of cellulose and polyvinyl alcohol,
Combination of cellulose and ethylene / vinyl acetate copolymer,
A combination of carboxymethylcellulose and polybutylene terephthalate.

The base material protective layer 19 preferably contains a lubricant or is applied to the surface. Thereby, the moldability and winding yield of the exterior material 2 are improved. Examples of the lubricant include those mentioned in the first embodiment. When the base material protective layer 19 contains a lubricant, the base material protective layer 19 preferably contains a lubricant on the side opposite to the base material layer 11. One type of lubricant may be used alone, or two or more types may be used in combination.
Moreover, it is preferable that the base material protective layer 19 contains the plasticizer mentioned in the first embodiment. Thereby, the moldability of the exterior material 2 improves. A plasticizer may be used individually by 1 type and may use 2 or more types together. When the base material protective layer 19 contains a plasticizer, the plasticizer is preferably contained uniformly in the base material protective layer 19.
The base material protective layer 19 preferably contains the elastomer component mentioned in the first embodiment. Thereby, the moldability of the exterior material 2 improves. An elastomer component may be used individually by 1 type, and may use 2 or more types together. When the substrate protective layer 19 contains an elastomer component, the elastomer component is preferably contained uniformly in the substrate protective layer 19.
Moreover, it is preferable that the base-material protective layer 19 contains the filler component quoted in 1st Embodiment. Thereby, the scratch resistance of the base material protective layer 19 is improved. When making the base material protective layer 19 contain a filler component, it is preferable that the filler component is contained on the side of the base material protective layer 19 opposite to the base material layer 11.

Moreover, it is preferable that the base material protective layer 19 contains the pigment from the point of design property. When a pigment is used, the pigment may be contained in any layer outside the metal foil layer 13. However, since the pigment dispersibility is excellent and the color tends to be uniform, the pigment is added to the base material protective layer 19. It is preferable to contain. Examples of the pigment are the same as those described in the first embodiment.
Moreover, it is preferable that the base material protective layer 19 has a crosslinked structure formed of a crosslinking agent in terms of water resistance. Examples of the crosslinking agent include the same ones as those mentioned in the first embodiment.
Moreover, the base material protective layer 19 may contain additives such as a flame retardant, an antiblocking agent, an antioxidant, a light stabilizer, a tackifier, and an antistatic agent in addition to those described above.

  The content of the water-soluble polysaccharide (A) in the base material protective layer 19 (100% by mass) is preferably 20% by mass or more, and preferably 40% by mass or more from the viewpoint that excellent electrolytic solution resistance and scratch resistance can be obtained. Is more preferable. In addition, the content of the water-soluble polysaccharide (A) in the base material protective layer 19 (100% by mass) is preferably 95% by mass or less, and preferably 90% by mass or less in that the effect of other components is easily obtained. More preferred.

From the point of adhesion between the base material layer 11 and the base material protective layer 19, the content of the adhesive resin (B) in the base material protective layer 19 (100% by mass) is preferably 5% by mass or more, and more preferably 30% by mass or more. Is more preferable. In addition, since the amount of the water-soluble polysaccharide (A) can be relatively increased and excellent electrolytic solution resistance and scratch resistance can be easily obtained, the adhesive resin (B ) Is preferably 80% by mass or less, and more preferably 50% by mass or less.
It is preferable that the adhesive resin (B) has a higher concentration as it is closer to the base material layer 11.

The mass ratio (A) / (B) of the water-soluble polysaccharide (A) and the adhesive resin (B) in the base material protective layer 19 is preferably 20/80 to 95/5, more preferably 60/40 to 90/10. preferable. When the mass ratio (A) / (B) is within the above range, it is easy to achieve both electrolytic solution resistance, scratch resistance, moldability, adhesion, and tensile strength.
The total amount of the water-soluble polysaccharide (A) and the adhesive resin (B) in the base material protective layer 19 (100% by mass) is excellent in electrolytic solution resistance, scratch resistance, moldability, adhesion, and tensile strength. 25 mass% or more is preferable, and 50 mass% or more is more preferable. Moreover, the upper limit of the total amount of the water-soluble polysaccharide (A) and the adhesive resin (B) is 100% by mass.

  When making the base material protective layer 19 contain a lubricant, 0.1-10 mass% is preferable and, as for content of the lubricant in the base material protective layer 19 (100 mass%), 1-5 mass% is more preferable. If content of the said lubricant is more than a lower limit, moldability will become more favorable. If the content of the lubricant is not more than the upper limit value, the lubricant bleeds to the base material layer 11 side of the base material protective layer 19 and suppresses a decrease in the adhesion between the base material layer 11 and the base material protective layer 19. Cheap.

  When making the base material protective layer 19 contain a plasticizer, 1-70 mass% is preferable and, as for content of the plasticizer in the base material protective layer 19 (100 mass%), 10-60 mass% is more preferable. If content of the said plasticizer is more than a lower limit, moldability will become more favorable. If content of the said plasticizer is below an upper limit, heat resistance will become more favorable.

  When making the base material protective layer 19 contain an elastomer component, 5-80 mass% is preferable and, as for content of the elastomer component in the base material protective layer 19 (100 mass%), 10-70 mass% is more preferable. If content of the said elastomer component is more than a lower limit, moldability will become more favorable. When the content of the elastomer component is not more than the upper limit value, the scratch resistance and the electrolytic solution resistance become better.

  When making the base-material protective layer 19 contain a filler component, 0.1-50 mass% is preferable and, as for content of the filler component in the base-material protective layer 19 (100 mass%), 1-30 mass% is more preferable. . If content of the said filler component is more than a lower limit, scratch resistance will become more favorable. If content of the said filler component is below an upper limit, moldability will become more favorable.

  When making the base material protective layer 19 contain a pigment, 0.1-30 mass% is preferable and, as for content of the pigment in the base material protective layer 19 (100 mass%), 5-20 mass% is more preferable. If content of the said pigment is in the said range, design property will become more favorable.

  The thickness of the base material protective layer 19 is preferably 3.0 to 10.0 μm, and more preferably 4.0 to 6.0 μm. When the thickness of the base material protective layer 19 is equal to or greater than the lower limit value, the electrolyte solution resistance and the scratch resistance become better. If the thickness of the base material protective layer 19 is not more than the upper limit value, the moldability becomes better.

(Production method)
Hereinafter, the manufacturing method of the exterior material 2 is demonstrated. However, the manufacturing method of the exterior material 2 is not limited to the following method. As a manufacturing method of the exterior material 2, the method which has the following process (Y1)-(Y4) is mentioned, for example.
(Y1) A step of forming a corrosion prevention treatment layer 14 on the metal foil layer 13.
(Y2) The process of laminating | stacking the base material layer 11 through the 1st contact bonding layer 12 on the opposite side to the side in which the corrosion prevention process layer 14 in the metal foil layer 13 was formed.
(Y3) A step of laminating the base material protective layer 19 on the side of the base material layer 11 opposite to the first adhesive layer 12.
(Y4) A step of laminating the sealant layer 16 on the corrosion prevention treatment layer 14 side of the metal foil layer 13 via the second adhesive layer 15.

Step (Y1):
The step (Y1) can be performed in the same manner as the step (X1) of the first embodiment.

Step (Y2):
The step (Y2) can be performed in the same manner as the step (X2) of the first embodiment.

Step (Y3):
For example, a coating liquid containing a water-soluble polysaccharide (A), an adhesive resin (B), and a lubricant to be used as necessary, an elastomer component, etc. is applied to the side of the base material layer 11 opposite to the first adhesive layer 12. The base material protective layer 19 is formed by drying. At this time, the base material protective layer 19 prepares, for example, a plurality of coating liquids containing water-soluble polysaccharides (A) having different polymerization degrees, and these coating liquids are converted into water-soluble polysaccharides (A) having a low polymerization degree. ) In the order of the coating liquid containing, and can be formed by drying.
As the coating liquid for forming the base material protective layer 19, for example, a dispersion obtained by mixing an aqueous dispersion of a water-soluble polysaccharide (A) with an adhesive resin (B) or the like can be used. The aqueous dispersion of the water-soluble polysaccharide (A) may contain alcohols.
0.5-20 mass% is preferable and, as for the solid content density | concentration of the coating liquid which forms the base-material protective layer 19, 1-10 mass% is more preferable. If the solid content concentration is at least the lower limit, drying after coating becomes easy. When the solid content concentration is not more than the upper limit value, the coatability becomes better.

Step (Y4):
The step (Y4) can be performed in the same manner as the step (X4) of the first embodiment.

The exterior material 1 is obtained by the steps (Y1) to (Y4) described above.
In addition, the manufacturing method of the exterior material 1 is not limited to the method of implementing the said process (Y1)-(Y4) sequentially. For example, the step (Y1) may be performed after performing the step (Y2). Further, the step (Y3) may be performed after performing the step (Y4).

  The exterior material 2 is provided with the base material protective layer 19 containing the water-soluble polysaccharide (A) and the adhesive resin (B) on the outside of the base material layer 11, so that sufficient moldability and electrolyte solution resistance are provided. In addition, it has excellent scratch resistance that can be endured for in-vehicle use. Moreover, in the base material protective layer 19, the polymerization degree of the water-soluble polysaccharide (A) on the opposite side to the base material layer 11 is higher than the polymerization degree of the water-soluble polysaccharide (A) on the base material layer 11 side. Therefore, particularly excellent scratch resistance can be exhibited while obtaining excellent adhesion between the substrate layer 11 and the substrate protective layer 19.

<Other embodiments>
The exterior material of the present invention is not limited to the exterior materials 1 and 2, and the base material protective layer containing the water-soluble polysaccharide (A) and the first material are within the range not impairing the effects of the present invention. Between the three adhesive layers, between the third adhesive layer and the base material layer, between the base material layer and the first adhesive layer, between the first adhesive layer and the metal foil layer, between the metal foil layer and the corrosion prevention treatment layer, Another layer may be provided between the corrosion prevention treatment layer and the second adhesive layer and between the second adhesive layer and the sealant layer. Moreover, you may have another layer between the base material protective layer containing a water-soluble polysaccharide (A) and adhesive resin (B), and a base material layer. For example, a corrosion prevention treatment layer may be formed between the metal foil layer and the first adhesive layer. If the corrosion prevention treatment layer is also formed on the first adhesive layer side of the metal foil layer, it becomes easier to suppress the first adhesive layer side of the metal foil layer from being corroded by the electrolytic solution.
Moreover, if the exterior material of this invention is in the range which does not impair the effect of this invention, it may have another layer on the outer side of a base-material protective layer. As the exterior material of the present invention, it is preferable that the base material protective layer is the outermost layer from the viewpoint that an effect of being excellent in electrolytic solution resistance and scratch resistance is easily obtained.
Moreover, it is preferable that a sealant layer is also an outermost layer from the point that the sealing performance by heat seal is acquired favorably.

Examples of the lithium ion battery formed using the exterior material of the present invention include lithium ion batteries used for portable terminal devices such as personal computers and mobile phones, video cameras, satellites, submarines, electric cars, and electric bicycles. Of these, an in-vehicle lithium ion battery such as an electric vehicle is preferable.
Lithium ion batteries include, for example, battery contents having a tab made of a positive electrode, a separator, a negative electrode, an electrolyte, and leads and a tab sealant in a container body in which the outer packaging material of the present invention is formed into a bag shape or the like. It is manufactured by housing and sealing so that the part is located outside. The lithium ion battery can adopt a known form except for having the exterior material of the present invention.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by the following description.
(Third adhesive layer 17, base material protective layer 18, base material protective layer 19)
Water dispersion of water-soluble polysaccharide A-1: An aqueous dispersion of TEMPO-oxidized cellulose obtained by the method described below.
(1) Reagents and materials Cellulose: Bleached kraft pulp (Fletcher Challenge Canada “Machenzie”),
TEMPO: Commercial product (Tokyo Chemical Industry Co., Ltd., 98%),
Sodium hypochlorite: commercially available product (manufactured by Wako Pure Chemical Industries, Ltd., Cl: 5%),
Sodium bromide: Commercial product (Wako Pure Chemical Industries, Ltd.).
(2) TEMPO oxidation reaction of cellulose A 2 L glass beaker was charged with 10 g of dry kraft pulp and 500 ml of ion-exchanged water and allowed to stand overnight to swell the pulp. The temperature was adjusted to 20.0 ° C. with a water bath with temperature control, and 0.1 g of TEMPO and 1 g of sodium bromide were added and stirred to obtain a pulp suspension. Furthermore, 5 mmol / g sodium hypochlorite per cellulose mass was added with stirring. At this time, about 1N sodium hydroxide aqueous solution was added to maintain the pH of the pulp suspension at about 10.5. Thereafter, the reaction was performed for 3 hours, and the pulp was sufficiently washed with ion-exchanged water to obtain TEMPO oxidized cellulose (water-soluble polysaccharide A-1). When the molecular weight of the obtained TEMPO-oxidized cellulose freeze-dried was measured by a viscosity method using a copper ethylenediamine solution, the degree of polymerization was 150.
(3) Dispersion treatment of TEMPO oxidized cellulose The obtained TEMPO oxidized cellulose was adjusted to a predetermined concentration in ion-exchanged water, and stirred for 30 minutes using a mixer (Osaka Chemical, Absolute Mill, 14,000 rpm). As a result, an aqueous dispersion of transparent water-soluble polysaccharide A-1 was obtained.
Water dispersion of water-soluble polysaccharide A-2: TEMPO oxidation in the same manner as the water dispersion of water-soluble polysaccharide A-1 except that the reaction time of the oxidation reaction of (2) was changed to 1.5 hours. An aqueous dispersion of cellulose (water-soluble polysaccharide A-2, degree of polymerization 290) was obtained.
Water dispersion of water-soluble polysaccharide A-3: TEMPO oxidized cellulose (like the water dispersion of water-soluble polysaccharide A-1) except that the reaction time of the oxidation reaction of (2) was changed to 30 minutes. An aqueous dispersion of water-soluble polysaccharide A-3 (degree of polymerization 480) was obtained.
Adhesive component B-1: Polyvinyl alcohol (trade name “PVA-124”, manufactured by Kuraray Co., Ltd.).
Adhesive component B-2: Acrylic resin (trade name “Cotax LH635”, manufactured by Toray Fine Chemical Co., Ltd.).
(Base material layer 11)
Film C-1: Nylon 6 film having a thickness of 25 μm.
(First adhesive layer 12)
Adhesive component D-1: Urethane adhesive (trade name “A525 / A50”, manufactured by Mitsui Chemicals Polyurethane Co., Ltd.).
(Metal foil layer 13)
Metal foil E-1: Soft aluminum foil 8079 material (manufactured by Toyo Aluminum Co., Ltd., thickness 40 μm).
(Corrosion prevention treatment layer 14)
Treatment agent F-1: “Sodium polyphosphate-stabilized cerium oxide sol” adjusted to a solid content concentration 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.
(Second adhesive layer 15)
Adhesive Component G-1: Polypropylene resin graft-modified with maleic anhydride (trade name “Admer”, manufactured by Mitsui Chemicals, Inc.).
(Sealant layer 16)
Film H-1: A film obtained by corona-treating the surface that is the inner surface of an unstretched polypropylene film (thickness 40 μm).

[Example 1]
Treatment agent F-1 was applied to one surface of metal foil E-1 and dried to form a corrosion prevention treatment layer 14 (thickness 200 nm) on one surface of metal foil layer 13. Next, the film C-1 is bonded to the opposite side of the corrosion prevention treatment layer 14 in the metal foil layer 13 by a dry laminating method using the adhesive component D-1, and the first adhesive layer 12 (thickness 4 μm) is interposed therebetween. The base material layer 11 was laminated. Thereafter, aging was performed at 60 ° C. for 6 days.
Next, on the side opposite to the first adhesive layer 12 of the base material layer 11, a coating liquid (solid content concentration 5 mass%) in which the adhesive component B-1 and distilled water are mixed is applied by a gravure coating method, A third adhesive layer 17 (thickness 1 μm) was formed by drying. Thereafter, an aqueous dispersion of the water-soluble polysaccharide A-1 (solid content concentration 2% by mass), an aqueous dispersion of the water-soluble polysaccharide A-2 (solid content concentration 2% by mass), and the water-soluble polysaccharide A-3 An aqueous dispersion (solid content concentration of 2 mass%) is applied to the side opposite to the base material layer 11 of the third adhesive layer 17 by a gravure coating method and dried in order to form a base material protective layer 18 (3-layer structure) 4 μm thick) was formed. The thickness of each of the three layers of the base material protective layer 18 was 1 μm, 1 μm, and 2 μm in order from the base material layer 11 side.
Next, the adhesive component G-1 is extruded by an extrusion device on the corrosion prevention treatment layer 14 side of the obtained laminate to form a second adhesive layer 15 (thickness 50 μm), and the film H-1 is bonded. The sealant layer 16 was formed by sandwich lamination. Then, the obtained laminate, 160 ° C., to obtain a sheathing material by heat pressing at 4kg ^/ cm 2, 2m ^/ min conditions.

[Example 2]
Treatment agent F-1 was applied to one surface of metal foil E-1 and dried to form a corrosion prevention treatment layer 14 (thickness 200 nm) on one surface of metal foil layer 13. Next, the film C-1 is bonded to the opposite side of the corrosion prevention treatment layer 14 in the metal foil layer 13 by a dry laminating method using the adhesive component D-1, and the first adhesive layer 12 (thickness 4 μm) is interposed therebetween. The base material layer 11 was laminated. Thereafter, aging was performed at 60 ° C. for 6 days.
Next, a coating liquid (solid content concentration 3 mass) obtained by mixing an aqueous dispersion of the water-soluble polysaccharide A-1 and the adhesive component B-1 so that the mass ratio (A) / (B) is 60/40. %), An aqueous dispersion of the water-soluble polysaccharide A-2 and an adhesive component B-1 mixed so that the mass ratio (A) / (B) is 60/40 (solid content concentration 3 mass) %), An aqueous dispersion of the water-soluble polysaccharide A-3 and an adhesive component B-1 mixed so that the mass ratio (A) / (B) is 90/10 (solid content concentration 2 mass) %) On the side of the base material layer 11 opposite to the first adhesive layer 12 and successively coated by a gravure coating method, and dried to form a base material protective layer 19 (thickness 4 μm) having a three-layer structure. The thickness of each of the three layers of the base material protective layer 19 was 1 μm, 1 μm, and 2 μm in order from the base material layer 11 side.
Next, the adhesive component G-1 is extruded by an extrusion device on the corrosion prevention treatment layer 14 side of the obtained laminate to form a second adhesive layer 15 (thickness 50 μm), and the film F-1 is bonded. The sealant layer 16 was formed by sandwich lamination. Then, the obtained laminate, 160 ° C., to obtain a sheathing material by heat pressing at 4kg ^/ cm 2, 2m ^/ min conditions.

[Comparative Example 1]
An exterior material was obtained in the same manner as in Example 1 except that the base material protective layer 18 was not formed.

[Comparative Example 2]
An exterior material was obtained in the same manner as in Example 1 except that the adhesive component B-2 was used instead of the adhesive component B-1, and the base material protective layer 18 was not formed.

[Comparative Example 3]
Implementation was carried out except that the base material protective layer (thickness 4 μm) was formed only with an aqueous dispersion of water-soluble polysaccharide A-1 (solid content concentration 2 mass%) instead of forming the multilayer base material protective layer 18. An exterior material was obtained in the same manner as in Example 1.

[Comparative Example 4]
Implementation was carried out except that the base material protective layer (thickness 4 μm) was formed only with an aqueous dispersion of water-soluble polysaccharide A-3 (solid content concentration 2 mass%) instead of forming the multilayer base material protective layer 19. An exterior material was obtained in the same manner as in Example 2.

[Evaluation of scratch resistance]
The outer surface (surface on the base material layer side) of the exterior material obtained in each example was rubbed by reciprocating 10 times with # 0000 steel wool (manufactured by Nippon Steel Wool) while applying a load of 150 g / cm ^2. The depth of the wound was measured with a displacement meter. The scratch resistance was evaluated according to the following criteria.
“◯”: The depth of the scratch on the surface is less than 1 μm.
“×”: The depth of the scratch on the surface is 1 μm or more.

[Evaluation of electrolyte resistance]
LiPF ₆ (relative to the mixed solution of ethylene carbonate / dimethyl carbonate / diethyl carbonate = 1/1/1 (mass ratio) on the outer surface (surface on the base material layer side) of the exterior material obtained in each example. Drop a few drops of electrolyte solution (lithium hexafluorophosphate) adjusted to 1.5 M and leave it in an environment of 25 ° C. and 65% RH for 24 hours to wipe off the electrolyte solution. Was confirmed by an optical microscope (manufactured by Shimadzu Corporation). The evaluation of electrolyte resistance was performed according to the following criteria.
“◯”: Surface alteration (whitening) was not observed.
"X": The surface was altered (whitened).

[Evaluation of moldability]
The exterior material obtained in each example was cut into a blank shape of 150 mm × 190 mm, cold-molded while changing the molding depth, and the moldability was evaluated. A punch having a shape of 100 mm × 150 mm, a punch corner R (RCP) of 1.5 mm, a punch shoulder R (RP) of 0.75 mm, and a die shoulder R (RD) of 0.75 mm was used. The moldability was evaluated according to the following criteria.
“A”: Deep drawing with a molding depth of 7 mm or more was possible without causing breakage and cracks.
“◯”: Deep drawing with a molding depth of 5 mm or more and less than 7 mm was possible without causing breakage or cracks.
“×”: Breaking and cracking occurred in deep drawing with a molding depth of less than 5 mm.

[Evaluation of adhesion]
The outer surface (surface on the base material layer side) of the obtained exterior material was cut into 6 pieces vertically and horizontally at intervals of 1 mm with a cutter to form a lattice pattern of a total of 25 sections. Cellotape (registered trademark) was adhered on this pattern, the tape was peeled off, and peeling of the surface layer was visually observed. The test described above was performed according to JIS K5600. The evaluation of adhesion was performed according to the following criteria.
“◯”: No peeling was observed.
"X": Peeling was observed in one section or more.
Table 1 shows the results of evaluation in Examples and Comparative Examples.

As shown in Table 1, Examples 1 and 2 which are exterior materials of the present invention have excellent scratch resistance in addition to sufficient moldability and electrolyte solution resistance. The adhesion of the protective layer was also excellent.
On the other hand, the exterior material of Comparative Example 1 in which the outermost layer was a layer formed of polyvinyl alcohol did not have sufficient scratch resistance and electrolyte resistance. In addition, the exterior material of Comparative Example 2 in which the outermost layer was a layer formed of an acrylic resin did not have sufficient scratch resistance.
Further, in Comparative Examples 3 and 4 in which the degree of polymerization of the water-soluble polysaccharide (A) forming the base material protective layer is not higher on the side opposite to the base material layer side than on the base material layer side, excellent electrolyte resistance And adhesion could not be achieved.

  DESCRIPTION OF SYMBOLS 1, 2 ... Lithium ion battery exterior material, 11 ... Base material layer, 11a ... 1st surface, 11b ... 2nd surface, 12 ... 1st contact bonding layer, 13 * ..Metal foil layer, 14 ... corrosion prevention treatment layer, 15 ... second adhesive layer, 16 ... sealant layer, 17 ... third adhesive layer, 18, 19 ... base material protective layer .

Claims (3)

A base material layer made of nylon film;
A first adhesive layer provided on the first surface side of the base material layer;
A metal foil layer provided on the opposite side of the base layer of the first adhesive layer;
A corrosion prevention treatment layer provided on the opposite side of the metal foil layer from the first adhesive layer;
A second adhesive layer provided on the opposite side of the corrosion prevention treatment layer from the metal foil layer;
A sealant layer provided on the opposite side of the corrosion prevention treatment layer of the second adhesive layer;
A third adhesive layer provided on the second surface side of the base material layer;
A base material protective layer provided on the side opposite to the base material layer of the third adhesive layer,
The base material protective layer contains the following water-soluble polysaccharide (A), and the degree of polymerization of the water-soluble polysaccharide (A) on the side opposite to the base material layer is the water-soluble polysaccharide (A) on the base material layer side. ) The degree of polymerization of the lithium ion battery exterior material is higher.
Water-soluble polysaccharide (A): At 85 ° C., at least one solvent selected from the group consisting of an aqueous alcohol solution containing 50% by mass of methanol, ethanol, propanol or isopropyl alcohol, and water, A polysaccharide that dissolves 1 part by mass or more per part. A base material layer made of nylon film;
A first adhesive layer provided on the first surface side of the base material layer;
A metal foil layer provided on the opposite side of the base layer of the first adhesive layer;
A corrosion prevention treatment layer provided on the opposite side of the metal foil layer from the first adhesive layer;
A second adhesive layer provided on the opposite side of the corrosion prevention treatment layer from the metal foil layer;
A sealant layer provided on the opposite side of the corrosion prevention treatment layer of the second adhesive layer;
A base material protective layer provided on the second surface side of the base material layer,
The base material protective layer contains the following water-soluble polysaccharide (A) and adhesive resin (B), and the degree of polymerization of the water-soluble polysaccharide (A) on the side opposite to the base material layer is the base material layer side. The exterior material for lithium ion batteries which is higher than the degree of polymerization of the water-soluble polysaccharide (A).
Water-soluble polysaccharide (A): At 85 ° C., at least one solvent selected from the group consisting of an aqueous alcohol solution containing 50% by mass of methanol, ethanol, propanol or isopropyl alcohol, and water, A polysaccharide that dissolves 1 part by mass or more per part.   The lithium according to claim 2, wherein the adhesive resin (B) is at least one selected from the group consisting of a polyvinyl resin, a polyolefin resin, a urethane resin, an epoxy resin, an acrylic resin, and a polyester resin. Exterior material for ion batteries.

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