JP7635303B2 - Exterior materials for power storage devices - Google Patents

Description

The present invention relates to batteries and capacitors used in mobile devices such as smartphones and tablets.
The present invention relates to an exterior material for electricity storage devices such as batteries and capacitors used for storing electricity in hybrid automobiles, electric automobiles, wind power generation, solar power generation, and nighttime electricity, and to an electricity storage device exteriorly covered with said exterior material.

In the claims and the present specification, the term "polyester polyol" means
The term is used to include: 1) polyesters having hydroxyl groups at both ends in the longitudinal direction of the main chain; 2) polyesters having carboxyl groups at both ends in the longitudinal direction of the main chain; and 3) polyesters having a hydroxyl group at one end in the longitudinal direction of the main chain and a carboxyl group at the other end.

In recent years, as mobile electrical devices such as smartphones and tablet terminals have become thinner and lighter, a laminate consisting of a heat-resistant resin layer (base material layer)/adhesive layer/metal foil layer/adhesive layer/thermoplastic resin layer (inner sealant layer) has been used as the exterior material of the power storage devices such as lithium ion secondary batteries, lithium polymer secondary batteries, lithium ion capacitors, and electric double layer capacitors mounted thereon, instead of the conventional metal can (see Patent Document 1). In addition, power sources for electric vehicles, large power sources for power storage, capacitors, etc. are increasingly being exteriorized with a laminate (exterior material) of the above configuration. The laminate is molded into a three-dimensional shape such as a substantially rectangular parallelepiped shape by performing stretch molding or deep drawing. By molding into such a three-dimensional shape, it is possible to secure a storage space for accommodating the main body of the power storage device.

Also, a configuration has been proposed in which a matte varnish layer (protective layer) is provided on the outside of the base layer in order to protect the exterior material and improve its formability (slipperiness). For the matte varnish layer, it is described that a matte varnish made by adding an appropriate amount of an inorganic material matting agent such as silica or kaolin to an olefin-based or alkyd-based synthetic resin such as a cellulose-based, polyamide-based, vinyl chloride-vinyl acetate-based, modified polyolefin-based, rubber-based, acrylic-based, or urethane-based resin (see Patent Document 2).

JP 2003-288865 A JP 2011-54563 A

For example, in the case of a battery exterior material, when the electrolyte is injected into the body during the manufacturing process of the battery, the electrolyte (containing a solvent) may adhere to the surface (outer surface) of the exterior material.
If the solvent resistance of the outer surface of the exterior material is poor, the appearance of the exterior material will be poor. For example, when a protective layer is formed from a urethane resin, the exterior material has good formability, but the solvent resistance of the outer surface of the exterior material is poor (sufficient solvent resistance is not obtained).

Furthermore, when a protective layer is formed from a fluororesin, the solvent resistance of the exterior material is good, but the adhesion of letters, bar codes, etc. printed on the surface (outer surface) of the exterior material is insufficient, and the printing is prone to bleeding, resulting in problems of poor printability.

The present invention has been made in consideration of this technical background, and aims to provide an exterior material for an electricity storage device that has excellent formability, can ensure good printability on the surface, and also has excellent solvent resistance, an exterior case for an electricity storage device, and an electricity storage device.

To achieve the above objective, the present invention provides the following means:

[1] An exterior material for an electricity storage device, comprising a base layer made of a heat-resistant resin, a sealant layer as an inner layer, and a metal foil layer disposed between the base layer and the sealant layer,
a protective layer is laminated on a surface of the base layer opposite to the metal foil layer;
The protective layer is an exterior material for an electricity storage device, characterized in that it contains 40 mass% or more of a polyester resin formed from a polyester polyol having a number average molecular weight of 5,000 to 50,000 and having a hydroxyl group or a carboxyl group independently at at least both ends, and a polyfunctional isocyanate curing agent containing at least an aliphatic polyfunctional isocyanate compound.

[2] An equivalent ratio [NCO]/[OH+], which is the ratio of the number of moles of the isocyanate group of the polyfunctional isocyanate curing agent to the total number of moles of the hydroxyl group and the number of moles of the carboxyl group.
2. The exterior packaging material for an electricity storage device according to item 1, wherein the molecular weight of the organic solvent is 0.5 to 5.

[3] The exterior material for an electricity storage device according to item 1 or 2, wherein the aliphatic polyfunctional isocyanate compound is at least one aliphatic polyfunctional isocyanate compound selected from the group consisting of an adduct of trimethylolpropane and an aliphatic diisocyanate compound, and an adduct of pentaerythritol and an aliphatic diisocyanate compound.

[4] The polyester resin constituting the protective layer is the polyester polyol,
4. The exterior packaging material for an electricity storage device according to any one of items 1 to 3, which is a polyester resin formed from the polyfunctional isocyanate curing agent and a trihydric or higher polyhydric alcohol.

[5] The exterior material for an electricity storage device according to any one of items 1 to 4, wherein the protective layer contains solid fine particles having an average particle size of 1 μm to 10 μm.

[6] The exterior material for an electricity storage device according to any one of items 1 to 5, wherein the protective layer contains a lubricant.

[7] The exterior material for an electricity storage device according to any one of items 1 to 6, wherein a colored layer is disposed between the base layer and the metal foil layer.

[8] The exterior material for an electricity storage device according to item 7 above, wherein the base layer and the colored layer are laminated and integrated via an easy-adhesion layer.

[9] An exterior case for an electricity storage device, comprising a molded article of the exterior material for an electricity storage device according to any one of items 1 to 8 above.

[10] A main body of an electricity storage device;
An exterior member made of the exterior material for an electricity storage device according to any one of items 1 to 8 and/or the exterior case for an electricity storage device according to item 9,
The power storage device, wherein the power storage device main body is exteriorly covered with the exterior member.

In the invention of [1], the protective layer is a polyester polyol having a hydroxyl group or a carboxyl group at least at each of both ends independently, and a polyfunctional isocyanate curing agent containing at least an aliphatic polyfunctional isocyanate compound, and the number average molecular weight is 5,000.
Since the composition contains 40% by mass or more of polyester resin with a molecular weight of 1000 to 50,000, it has excellent moldability, can be printed in a good condition on the surface of the exterior material (surface of the protective layer), and the surface of the protective layer also has excellent solvent resistance.

In the invention [2], since the equivalent ratio [NCO]/[OH+COOH] is in the range of 0.5 to 5, printing can be performed in a better condition on the surface of the packaging material (the surface of the protective layer), and the solvent resistance of the surface of the protective layer can be further improved.

In the invention [3], since the aliphatic polyfunctional isocyanate compound is the specific aliphatic polyfunctional isocyanate compound, printing can be performed in a better state on the surface of the exterior material (the surface of the protective layer), and the solvent resistance of the surface of the protective layer can be further improved.

In the invention of [4], the polyester resin constituting the protective layer is a polyester polyol,
Since the resin is formed from a polyfunctional isocyanate curing agent and a trivalent or higher polyhydric alcohol, the crosslinking density of the resin is high, which can further improve the solvent resistance of the surface of the exterior material (the surface of the protective layer).

In the invention [5], since the protective layer contains solid fine particles having an average particle size of 1 μm to 10 μm, the moldability of the packaging material can be further improved.

In the invention [6], since the protective layer contains a lubricant, the slipperiness of the surface of the packaging material (the surface of the protective layer) can be improved, and thus the formability can be improved.

In the invention of [7], since the colored layer is disposed between the base layer (heat-resistant resin layer) and the metal foil layer, the color of the colored layer is visible through the base layer (heat-resistant resin layer), improving the design of the exterior material. In addition, since the colored layer is disposed on the inner side of the base layer, the colored layer is not scratched or the color is not peeled off, ensuring durability.

In the invention of [8], the base layer and the colored layer are laminated and integrated via the easy-adhesion layer,
This can sufficiently prevent the colored layer from peeling off from the base layer when the exterior material is molded.

The invention [9] can provide an exterior case for an electricity storage device that is molded in a good condition, while ensuring good printability on the surface and also having excellent solvent resistance.

The invention [10] provides an electricity storage device that is packaged with an exterior material for an electricity storage device and/or an exterior case that can ensure good printability on the surface and has excellent solvent resistance and is molded in a good state.

1 is a cross-sectional view showing one embodiment of an exterior material for an electricity storage device according to the present invention. 1 is a cross-sectional view showing one embodiment of an electricity storage device according to the present invention. 3 is a perspective view showing the exterior material (planar), the main body of the electricity storage device, and the exterior case (a molded body molded into a three-dimensional shape) constituting the electricity storage device of FIG. 2 in a separated state before being heat-sealed. FIG.

One embodiment of an exterior material 1 for an electricity storage device according to the present invention is shown in Fig. 1. The exterior material 1 for an electricity storage device of this embodiment is suitably used as a packaging material for a lithium ion secondary battery case, but is not particularly limited to such an application.

The exterior material 1 for an electricity storage device has a configuration in which a base material layer (heat-resistant resin layer) 2 is laminated integrally to one surface (upper surface) of a metal foil layer 4 via a first adhesive layer (outer adhesive layer) 5, a sealant layer (inner layer) 3 is laminated integrally to the other surface (lower surface) of the metal foil layer 4 via a second adhesive layer (inner adhesive layer) 6, and a protective layer 7 is laminated integrally to the surface of the base material layer 2 opposite to the metal foil layer 4 (see FIG. 1 ).

In this embodiment, an easy-adhesion layer 8 is laminated on the lower surface of the base material layer (heat-resistant resin layer) 2, a colored layer 9 is laminated on the lower surface of the easy-adhesion layer 8, and the colored layer 9 and the metal foil layer 4 are bonded to a first adhesive layer 5.
In other words, the colored layer 9 is disposed between the metal foil layer 4 and the base layer (heat-resistant resin layer) 2.
An easy-adhesion layer 8 is laminated on the lower surface of the heat-resistant resin layer 2 by a gravure coating method, and the easy-adhesion layer 8
The colored layer 9 is laminated on the lower surface of the substrate 1 by printing.

[Protective Layer]
In the present invention, the protective layer 7 contains 40% by mass or more of a polyester resin formed from a polyester polyol having a number average molecular weight of 5,000 to 50,000 and having a hydroxyl group or a carboxyl group at each of at least both longitudinal ends of the main chain, and a polyfunctional isocyanate curing agent containing at least an aliphatic polyfunctional isocyanate compound. Because of the adoption of such a configuration, the exterior packaging material 1 of the present invention has excellent moldability, can be printed in a good condition on the surface of the exterior packaging material (the surface of the protective layer 7), and the surface of the protective layer 7 also has excellent solvent resistance.

As the polyester polyol, for example, a polyester polyol having a hydroxyl group or a carboxyl group at each of at least both ends independently, which is obtained by mixing a polyhydric alcohol and a polybasic carboxylic acid and carrying out a condensation polymerization reaction, is preferably used in terms of further improving the solvent resistance. That is, the polyester polyol is preferably a condensation polymer of a polyhydric alcohol and a polybasic carboxylic acid. For example, by mixing a polyhydric alcohol and a dicarboxylic acid and carrying out a condensation polymerization reaction at 210°C for 20 hours,
The "polyester polyol having a hydroxyl group or a carboxyl group at at least both ends, independently, can be produced. The polyhydric alcohol is not particularly limited, but examples thereof include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,6-hexanediol, neopentyl glycol, 1
, 4-butylene glycol, trimethylolpropane, glycerin, 1,9-nanonediol, 3-methyl-1,5-pentanediol, etc. The polybasic carboxylic acid is not particularly limited, but examples thereof include dicarboxylic acids such as aliphatic dicarboxylic acids and aromatic dicarboxylic acids. The aliphatic dicarboxylic acid is not particularly limited, but examples thereof include adipic acid, succinic acid, azelaic acid, suberic acid, sebacic acid, glutaric acid, maleic anhydride, itaconic anhydride, etc. The aromatic dicarboxylic acid is not particularly limited, but examples thereof include isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride,
Examples of the acid include phthalic anhydride, trimellitic acid, and pyromellitic acid.

The polyester polyol has a number average molecular weight (Mn) of 5,000 to 50,000.
A polyester polyol having a number average molecular weight of less than 5,000 is used. If the number average molecular weight is less than 5,000, the solvent resistance is poor, and when a solvent adheres to the outer surface of the exterior material, the surface of the protective layer becomes cloudy. On the other hand, if the number average molecular weight exceeds 50,000, the viscosity increases, and the viscosity of the coating solution increases, making coating difficult or reducing the coating properties. Among these, the number average molecular weight of the polyester polyol is preferably 8,000 to 40,000, and more preferably 10,000 to 30,000.
It is particularly preferable that the number average molecular weight is in the range of 5,000 to 45,000. Note that the number average molecular weight of the polyester polyol is in the range of 5,000 to 45,000 in order to sufficiently improve the coatability (applicability).

The number average molecular weight of the polyester polyol is a value calculated in terms of polystyrene by gel permeation chromatography (GPC). Specifically, for example, the number average molecular weight of the polyester polyol is measured by using KF805L, KF803L, and KF802 (all manufactured by Showa Denko K.K.) as columns at a column temperature of 40° C., tetrahydrofuran (THF) as an eluent, and a flow rate of 0.2 mL/min.
/min, detector: differential refractive index (RI) meter, sample concentration: 0.02 mass%, and number average molecular weight measured using polystyrene with known molecular weight as a standard sample.

The aliphatic polyfunctional isocyanate compound (curing agent) is not particularly limited, but examples thereof include hexamethylene diisocyanate (HMDI), tetramethylene diisocyanate, 1,2-propylene diisocyanate, and isophorone diisocyanate (I
PDI) and the like. Thus, the aliphatic polyfunctional isocyanate compound includes both acyclic and cyclic (alicyclic) compounds. Modified aliphatic polyfunctional isocyanate compounds may also be used. The modified aliphatic polyfunctional isocyanate compound is not particularly limited, but examples thereof include modified aliphatic polyfunctional isocyanate compounds obtained by polymerization reactions such as isocyanuration, polymerization, and carbodiimidization. Specific examples thereof include dimers, trimers, biurets, and allophanates of aliphatic polyfunctional isocyanate compounds, as well as polyisocyanates having a 2,4,6-oxadiazinetrione ring obtained from carbon dioxide and an aliphatic polyfunctional isocyanate compound monomer.

Among them, the aliphatic polyfunctional isocyanate compound is at least one selected from the group consisting of an adduct between trimethylolpropane and an aliphatic polyfunctional isocyanate compound and an adduct between pentaerythritol and an aliphatic polyfunctional isocyanate compound.
It is preferable to use at least one kind of aliphatic polyfunctional isocyanate compound, and it is particularly preferable to use at least one kind of aliphatic polyfunctional isocyanate compound selected from the group consisting of an adduct of trimethylolpropane and an aliphatic diisocyanate compound and an adduct of pentaerythritol and an aliphatic diisocyanate compound.

As the curing agent, an aromatic polyfunctional isocyanate compound may be used in combination with the aliphatic polyfunctional isocyanate compound within a range that does not impair the effects of the present invention. The aromatic polyfunctional isocyanate compound is not particularly limited, but examples thereof include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and the like.
), methylene diphenyl diisocyanate, and the like.

The content of the aliphatic polyfunctional isocyanate compound in the polyfunctional isocyanate curing agent is preferably set to 30% by mass to 100% by mass, more preferably 50% by mass to 100% by mass.
It is more preferable that the content be set to 00% by mass, and particularly preferable that the content be set to 70% to 100% by mass.

The polyester resin constituting the protective layer 7 is "the polyester polyol",
The polyester resin may be formed from "the polyfunctional isocyanate curing agent containing the aliphatic polyfunctional isocyanate compound" and "an aliphatic compound having a plurality of functional groups in one molecule that can react with an isocyanate group." The aliphatic compound may contain oxygen, nitrogen,
Compounds having atoms such as sulfur and chlorine bonded thereto are also included. The aliphatic compounds do not include the polyester polyol and the polyfunctional isocyanate compound. It is preferable to use an aliphatic compound having a molecular weight smaller than the number average molecular weight of the polyester polyol. In this case, the curing reaction proceeds quickly, which is advantageous in improving productivity. In addition, even if a manufacturing procedure is adopted in which a protective layer is formed first during the manufacture of an exterior material, and then a metal foil and a sealant film (sealant layer) are laminated, the protective layer can be sufficiently prevented from adhering to the roll of the processing machine and peeling off (contaminating the surface of the roll). Among these, the molecular weight of the "aliphatic compound having multiple functional groups in one molecule that can react with an isocyanate group" is 6.
A range of 0 to 9,500 is more preferable, and a range of 100 to 1,000 is particularly preferable.

Regarding the aliphatic compound, the functional group capable of reacting with an isocyanate group is not particularly limited, but examples thereof include a hydroxyl group, an amino group, and a carboxyl group. Specific examples of the "aliphatic compound having a plurality of functional groups capable of reacting with an isocyanate group in one molecule" are not particularly limited, but examples thereof include a polyhydric alcohol, an aliphatic diamine, and a dicarboxylic acid. The polyhydric alcohol is an alcohol having two or more alcoholic hydroxyl groups in one molecule. The polyhydric alcohol is not particularly limited, but examples thereof include trimethylolethane, trimethylolpropane (TMP), etc.
, trimethylolbutane, pentaerythritol, 1,2,6-hexanetriol, methylpentanediol, dimethylbutanediol, ethylene glycol, glycerin, carbitol, sorbitol, etc. Among these, it is preferable to use a polyhydric alcohol having a valence of three or more.

The content of the aliphatic compound in the polyester resin is preferably 1% by mass to 30% by mass, more preferably 1% by mass to 15% by mass, and even more preferably 3% by mass to 5% by mass.
A content of 10% by weight is particularly preferred.

The content of the polyester resin in the protective layer 7 is 40% by mass to 99.9% by mass.
In particular, the content of the polyester resin in the protective layer 7 is preferably set to 50% by mass to 95% by mass, more preferably 60% by mass to 90% by mass.
It is particularly preferable to set it to

The protective layer 7 is preferably further configured to contain solid fine particles. By containing the solid fine particles, good slipperiness is imparted to the surface (outer surface of the protective layer 7) of the electrical storage device exterior material 1, and the formability of the electrical storage device exterior material 1 can be further improved. From the viewpoint of improving slipperiness, the gloss value of the surface (outer surface) of the protective layer 7 is preferably set to 30% or less, more preferably set to 1% to 15%. The gloss value is a value obtained by measuring at a reflection angle of 60° using a gloss meter "micro-TRI-gloss-s" manufactured by BYK. The solid fine particles are not particularly limited, and examples thereof include silica fine particles, alumina fine particles, kaolin fine particles, calcium oxide fine particles, calcium carbonate fine particles, calcium sulfate fine particles, barium sulfate fine particles, calcium silicate fine particles, silicone resin beads, acrylic resin beads, and fluororesin beads. Among these, it is preferable to use silica fine particles, barium sulfate fine particles, and acrylic resin beads. It is preferable to use solid fine particles having an average particle size of 1 μm to 10 μm as the solid fine particles.

The content of the solid fine particles in the protective layer 7 is preferably set to 0.1% by mass to 60% by mass. By setting the content to 0.1% by mass or more, the slipperiness during molding can be improved, and by setting the content to 60% by mass or less, the coating processability during the formation of the protective layer can be improved and the shape retention of the protective layer can be sufficiently ensured. Among these, the content of the solid fine particles in the protective layer 7 is more preferably set to 5% by mass to 45% by mass, and particularly preferably set to 10% by mass to 30% by mass.

The protective layer 7 preferably contains a lubricant. By containing a lubricant, good slip properties are imparted, and it is possible to further improve the formability of the exterior material for an electrical storage device 1. The lubricant is not particularly limited, and examples thereof include fatty acid amides, silicones, and waxes (polyethylene wax, fluorine-containing polyethylene wax, etc.).

The protective layer 7 may contain an additive. The additive is not particularly limited, but examples thereof include a reaction accelerator. The reaction accelerator is for efficiently promoting the reaction between the polyester polyol and the polyfunctional isocyanate compound. The reaction accelerator is not particularly limited, but examples thereof include dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dimaleate, and tertiary amines (tributylamine, triethanolamine, etc.).

The thickness (thickness after drying) of the protective layer 7 is preferably set to 1 μm to 10 μm. In order to set the thickness of the protective layer 7 in such a thin range, the protective layer 7 is preferably formed of a coating film (a coating film formed by coating).

[Base material layer (heat-resistant resin layer)]
The base layer (heat-resistant resin layer) 2 is a member that mainly plays a role in ensuring good moldability as an exterior material, that is, prevents breakage due to necking of the metal foil during molding. As the heat-resistant resin constituting the base layer 2, a heat-resistant resin that does not melt at the heat-sealing temperature when the exterior material 1 is heat-sealed is used. As the heat-resistant resin, a heat-resistant resin having a melting point 10°C or more higher than the melting point of the thermoplastic resin constituting the sealant layer 3 is preferably used, and a heat-resistant resin having a melting point 20°C or more higher than the melting point of the thermoplastic resin is particularly preferably used.

The base layer (heat-resistant resin layer) 2 is preferably composed of a heat-resistant resin stretched film having a hot water shrinkage rate of 2% to 20%. A hot water shrinkage rate of 2% or more can adequately prevent the colored layer 9 from peeling off from the heat-resistant resin layer 2 when used in a somewhat severe environment such as high temperature and humidity. Furthermore, a hot water shrinkage rate of 20% or less can adequately prevent the colored layer 9 of the exterior packaging material 1 from peeling off from the heat-resistant resin layer 2 when molding such as deep drawing and stretch molding is performed. Among these, the heat-resistant resin stretched film is preferably composed of a heat-resistant resin stretched film having a hot water shrinkage rate of 2.5 to 10%.
It is preferable to use a heat-resistant resin stretched film having a hot water shrinkage rate of 3.0% to 6.
It is more preferable to use a heat-resistant resin stretched film having a hot water shrinkage rate of 3.5 or less.
It is particularly preferable to use a heat-resistant resin stretched film having a heat resistance of from 1.0% to 5.0%.

The "hot water shrinkage rate" refers to the shrinkage rate of a test piece (10 cm x 10
This is the rate of dimensional change in the stretching direction of a test piece before and after immersion in hot water at 95° C. for 30 minutes, and is calculated by the following formula.

Hot water shrinkage rate (%) = {(X-Y)/X} x 100
X: Dimension in the stretching direction before immersion treatment. Y: Dimension in the stretching direction after immersion treatment.

When a biaxially stretched film is used, the hot water shrinkage rate is the average value of the dimensional change rates in the two stretching directions.

The hot water shrinkage rate of the heat-resistant resin stretched film can be controlled, for example, by adjusting the heat setting temperature during stretching.

The heat-resistant resin stretched film 2 is not particularly limited, and examples thereof include stretched polyamide films such as stretched nylon films, stretched polyester films, and the like. Among them, it is particularly preferable to use biaxially stretched polyamide films such as biaxially stretched nylon films, biaxially stretched polybutylene terephthalate (PBT) films, biaxially stretched polyethylene terephthalate (PET) films, or biaxially stretched polyethylene naphthalate (PEN) films as the heat-resistant resin stretched film 2. It is also preferable to use a heat-resistant resin biaxially stretched film stretched by a simultaneous biaxial stretching method as the heat-resistant resin stretched film 2. It is also preferable to use a heat-resistant resin biaxially stretched film in which the ratio (MD/TD) of the "hot water shrinkage rate in the M direction" to the "hot water shrinkage rate in the T direction" is in the range of 0.9 to 1.1. When a configuration in which the ratio (MD/TD) is in the range of 0.9 to 1.1 is adopted, an exterior material 1 having particularly good moldability can be obtained. The "M direction" means the "machine flow direction", and the "T direction" means the "direction perpendicular to the M direction". The nylon is not particularly limited, but examples thereof include nylon 6, nylon 6,6, and MXD nylon. The heat-resistant resin stretched film layer 2 may be formed of a single layer (single stretched film), or may be formed of a multilayer structure (stretched PET film/stretched polyamide film) such as a stretched polyester film/stretched polyamide film.
The film may be formed of a multi-layer material such as a stretched nylon film.

Among them, it is preferable to use a biaxially oriented polyamide film having a shrinkage rate of 2 to 20%, a biaxially oriented polyethylene naphthalate (PEN) film having a shrinkage rate of 2 to 20%, or a biaxially oriented polyethylene terephthalate (PET) film having a shrinkage rate of 2 to 20% as the heat-resistant resin stretched film layer 2. In this case, the effect of preventing the colored layer 9 from peeling off from the heat-resistant resin layer 2 can be further improved during molding, sealing, use under somewhat severe environments such as high temperature and humidity, etc.

The thickness of the base material layer (heat-resistant resin layer) 2 is preferably 12 μm to 50 μm. When a polyester film is used, the thickness is preferably 12 μm to 50 μm, and when a nylon film is used, the thickness is preferably 15 μm to 50 μm. By setting the thickness to be equal to or greater than the above-mentioned preferable lower limit, sufficient strength as an exterior material can be ensured, and by setting the thickness to be equal to or less than the above-mentioned preferable upper limit, stress during stretch forming or drawing can be reduced, thereby further improving formability.

[Easy-adhesion layer]
An easy-adhesion layer 8 may be laminated on the inner surface (the surface on the metal foil layer 4 side) of the base layer (heat-resistant resin layer) 2. By coating the surface of the heat-resistant resin layer 2, which originally has poor adhesion, with a polar resin or the like having excellent tackiness and adhesiveness, and laminating the easy-adhesion layer 8, it is possible to further improve the adhesion and adhesion with the colored layer 9. Note that it is preferable to enhance the wettability of the inner surface of the heat-resistant resin layer 2 (the surface on which the easy-adhesion layer 8 is laminated) by performing a corona treatment or the like in advance before laminating the easy-adhesion layer 8.

The method for forming the easy-adhesion layer 8 is not particularly limited. For example,
The adhesive layer 8 can be formed by applying an aqueous emulsion (water-based emulsion) of one or more resins selected from the group consisting of epoxy resins, urethane resins, acrylic ester resins, methacrylic ester resins, polyester resins, and polyethyleneimine resins to the surface of the substrate 2 and drying the emulsion. The application method is not particularly limited, and examples thereof include a spray coating method, a gravure roll coating method, a reverse roll coating method, and a lip coating method.

The easy-adhesion layer 8 is preferably configured to contain one or more resins selected from the group consisting of epoxy resins, urethane resins, acrylic ester resins, methacrylic ester resins, polyester resins, and polyethyleneimine resins. By adopting such a configuration, the adhesive strength between the heat-resistant resin layer 2 and the colored layer 9 can be further improved, and when the exterior material is subjected to molding such as deep drawing and stretch molding, or when the exterior material is sealed for sealing, the colored layer 9 can be sufficiently prevented from peeling off from the heat-resistant resin layer 2,
Even when the packaging material 1 is used in a somewhat severe environment such as high temperature and high humidity, the colored layer 9 can be sufficiently prevented from peeling off from the heat-resistant resin layer 2.

Among them, it is particularly preferable that the easy-adhesion layer 8 contains a urethane resin and an epoxy resin, or a (meth)acrylic acid ester resin and an epoxy resin, in which case the adhesive strength between the heat-resistant resin layer 2 and the colored layer 9 can be further improved.

In the case of adopting the former configuration, the mass ratio of the urethane resin/epoxy resin in the adhesive layer 8 is preferably in the range of 98/2 to 40/60, and in this case, the adhesive strength between the heat-resistant resin layer 2 and the colored layer 9 can be further improved.
When the content ratio of the urethane resin becomes larger than the content ratio of the epoxy resin by mass (98/2),
It is not preferable because the degree of crosslinking is insufficient, making it difficult to obtain sufficient solvent resistance and adhesive strength. On the other hand, if the content ratio of the urethane resin is smaller than the content ratio by mass of the urethane resin/epoxy resin (40/60), it is not preferable because it takes too long to complete the crosslinking.
In particular, the mass ratio of the urethane resin/epoxy resin in the adhesive layer 8 is 90/10 to 50/10.
A range of 0/50 is more preferable.

In addition, in the case of adopting the latter configuration, the content mass ratio of the (meth)acrylic ester resin/epoxy resin in the easy-adhesion layer 8 is preferably in the range of 98/2 to 40/60, in which case the adhesive strength between the heat-resistant resin layer 2 and the colored layer 9 can be further improved. If the content ratio of the (meth)acrylic ester resin is greater than the content mass ratio of the (meth)acrylic ester resin/epoxy resin (98/2), the degree of crosslinking becomes insufficient, making it difficult to obtain sufficient solvent resistance and adhesive strength, which is not preferable. On the other hand, if the content ratio of the (meth)acrylic ester resin is smaller than the content mass ratio of the (meth)acrylic ester resin/epoxy resin (40/60), it takes too long to complete the crosslinking, which is not preferable. Among them, the content mass ratio of the (meth)acrylic ester resin/epoxy resin in the easy-adhesion layer 8 is more preferably in the range of 90/10 to 50/50.

A surfactant such as glycols or an ethylene oxide adduct of glycol may be added to the resin aqueous emulsion (resin-water emulsion) for forming the easy-adhesion layer 8. In this case, a sufficient defoaming effect can be obtained in the resin aqueous emulsion, so that the easy-adhesion layer 8 having excellent surface smoothness can be formed. The surfactant is preferably contained in the resin aqueous emulsion in an amount of 0.01% by mass to 2.0% by mass.

In addition, it is preferable that the resin aqueous emulsion (resin-aqueous emulsion) for forming the easy-adhesion layer 8 contains inorganic fine particles such as silica and colloidal silica, and in this case, a blocking prevention effect can be obtained.
It is preferable to add 0.1 to 10 parts by mass per 00 parts by mass of the inorganic filler.

The amount of the easy-adhesion layer 8 formed (solid content after drying) is preferably in the range of 0.01 g/m ² to 0.5 g/m ^2. When it is 0.01 g/m ² or more, the heat-resistant resin stretched film layer 2 and the colored ink layer 9 can be sufficiently bonded, and when it is 0.5 g/m ² or less, the cost can be reduced and it is economical.

The content of the resin in the easy-adhesion layer (after drying) 8 is 88% by mass to 99.9% by mass.
It is preferable that:

[Colored layer]
A configuration may be adopted in which a colored layer 9 is disposed between the base material layer 2 and the metal foil layer 4. By adopting such a configuration, it is possible to impart a color (including an achromatic color) or a design to the outer surface side of the exterior packaging material 1.

The colored layer 9 is not particularly limited, but examples thereof include a black ink layer, a white ink layer, a gray ink layer, a red ink layer, a blue ink layer, a green ink layer, and a yellow ink layer.

The black ink layer 9 will now be described. The black ink layer 10 is usually formed of a composition containing carbon black.

Among them, the black ink layer 9 preferably contains carbon black, diamine, polyol and a hardener, but is not limited to this particular composition.

In the black ink layer (ink layer after drying) 9, the carbon black content is preferably 15% by mass to 60% by mass, and the total content of the diamine, polyol and curing agent is preferably 40% by mass to 85% by mass.
It is particularly preferably up to 50% by weight.

If the carbon black content is less than 15% by mass, the metallic luster of the metal foil layer 4 remains, impairing the solid feel, and partial color unevenness is likely to occur during molding, which is not preferred. On the other hand, if the carbon black content exceeds 60% by mass, the black ink layer 9 becomes hard and brittle, reducing the adhesive strength to the metal foil layer 4, which may cause peeling between the metal foil layer 4 and the black ink layer 9 during molding, which is not preferred.

The black ink layer 9 preferably contains 2 to 20 parts by mass of the curing agent per 100 parts by mass of the total amount of the carbon black, the diamine, and the polyol. If the curing agent is less than 2 parts by mass, peeling between the metal foil layer 4 and the black ink layer 9 is likely to occur during molding, and if the curing agent is more than 20 parts by mass, blocking occurs when the wound exterior material 1 is unwound, and the heat-resistant resin layer 2 and the sealant layer (thermoplastic resin layer) 3 are easily peeled off.
This is undesirable because it is likely to cause problems such as transfer and adhesion to the outer surface of the device.

The carbon black preferably has an average particle size of 0.2 μm to 5 μm.

The diamine is not particularly limited, but examples thereof include ethylenediamine,
Examples of the diamine include dimer diamine, 2-hydroxyethyl ethylenediamine, 2-hydroxyethyl propylenediamine, dicyclohexylmethanediamine, 2-hydroxyethyl propylenediamine, etc. Among them, it is preferable to use one or more diamines selected from the group consisting of ethylenediamine, dimer diamine, 2-hydroxyethyl ethylenediamine, 2-hydroxyethyl propylenediamine, and dicyclohexylmethanediamine as the diamine.

The diamine reacts with the curing agent (such as isocyanate) more quickly than the polyol, and can achieve curing in a short time. That is, the diamine reacts with the curing agent together with the polyol to promote crosslinking and curing of the ink composition.

The polyol is not particularly limited, but it is preferable to use one or more polyols selected from the group consisting of polyurethane polyols, polyester polyols, and polyether polyols.

The number average molecular weight of the polyol is preferably in the range of 1,000 to 8,000.
When the molecular weight is 8,000 or more, the adhesive strength after curing can be increased, and when the molecular weight is 8,000 or less, the reaction rate with the curing agent can be increased.

The curing agent is not particularly limited, and examples thereof include isocyanate compounds. Examples of the isocyanate compound that can be used include various aromatic, aliphatic, and alicyclic isocyanate compounds. Specific examples include tolylene diisocyanate (TDI), diphenylmethane diisocyanate, hexamethylene diisocyanate (HDI), and isophorone diisocyanate.

The colored ink layer (excluding the black ink layer) 9 will be described. The colored ink layer (excluding the black ink layer) 9 is preferably composed of a cured film of a colored ink composition containing a two-component curing type polyester urethane resin binder made of a polyester resin as a base material and a polyfunctional isocyanate compound as a curing agent, and a colored pigment containing an inorganic pigment.

The color pigment is preferably one containing at least an inorganic pigment. In addition to the inorganic pigment, examples of the color pigment include azo pigments, phthalocyanine pigments, and condensed polycyclic pigments. The inorganic pigment is not particularly limited, but examples thereof include carbon black, calcium carbonate, titanium oxide, zinc oxide, iron oxide, and aluminum powder. The inorganic pigment is preferably one having an average particle size of 0.1 μm to 5 μm, and more preferably one having an average particle size of 0.5 μm to 2.5 μm. When dispersing the color pigment, it is preferable to disperse the color pigment using a pigment dispersing machine. When dispersing the color pigment, a pigment dispersant such as a surfactant can also be used.

It is preferable that 50% by mass or more of the color pigment is composed of the inorganic pigment. In this case, it is possible to form a color ink layer 9 of a specific color tone that can obtain a sufficient hiding power for hiding the metal foil layer 4 and can sufficiently impart a heavy and luxurious feel. Among them, it is more preferable that 60% by mass or more of the color pigment is composed of the inorganic pigment.

The thickness (after drying) of the colored layer 9 is preferably 1 μm to 4 μm. When the thickness is 1 μm or more, the color tone of the colored layer 9 does not remain transparent, and the color and gloss of the metal foil layer 4 can be sufficiently concealed. When the thickness is 4 μm or less, partial cracking of the colored layer 9 during molding can be sufficiently prevented.

The colored layer 9 is not particularly limited, but may be, for example,
The ink composition can be formed by printing (applying) 1) an ink composition containing carbon black, a diamine, a polyol, a curing agent, and an organic solvent, or 2) a colored ink composition containing a two-component curing type polyester urethane resin binder made of a polyester resin as a base material and a polyfunctional isocyanate compound as a curing agent, and a colored pigment containing an inorganic pigment, on the surface of the easy-adhesion layer 8 on the lower surface of the heat-resistant resin layer 2 by gravure printing or the like. The organic solvent is not particularly limited, and examples thereof include toluene.

The method for forming the colored layer 9 is not particularly limited, but examples thereof include gravure printing, reverse roll coating, and lip roll coating.

[Sealant layer (inner layer)]
The sealant layer (inner layer) 3 is formed of a thermoplastic resin layer.
The inner layer 3 provides excellent chemical resistance against highly corrosive electrolytes used in lithium ion secondary batteries and the like, and also plays a role in imparting heat sealability to the exterior packaging material 1.

The thermoplastic resin layer 3 is preferably, but not limited to, an unstretched thermoplastic resin film layer. The thermoplastic resin unstretched film layer 3 is preferably, but not limited to, an unstretched film made of at least one thermoplastic resin selected from the group consisting of polyethylene, polypropylene, olefin copolymers, acid-modified products thereof, and ionomers.

Among these, a three-layer structure in which a random copolymer layer containing propylene and other copolymer components excluding propylene as copolymer components is laminated on both sides of an intermediate layer containing an elastomer-modified olefin-based resin as the thermoplastic resin layer 3 is more preferable in terms of ensuring sufficient insulation during heat sealing.

The elastomer-modified olefin resin (polypropylene block copolymer) constituting the intermediate layer is preferably made of an elastomer-modified homopolypropylene and/or an elastomer-modified random copolymer. The elastomer-modified random copolymer is an elastomer-modified random copolymer containing "propylene" and "other copolymer components other than propylene" as copolymer components. The "other copolymer components other than propylene" are not particularly limited, but may be, for example, ethylene, 1-butene, 1-hexene,
Examples of the elastomer include olefin components such as 1-pentene and 4-methyl-1-pentene, as well as butadiene. The elastomer is not particularly limited, but it is preferable to use an olefin-based thermoplastic elastomer. The olefin-based thermoplastic elastomer is not particularly limited, but examples thereof include EPR (ethylene propylene rubber), propylene-butene elastomer, propylene-butene-ethylene elastomer, EPDM (
Ethylene-propylene-diene rubber, etc., are examples of the elastomer-modified olefin-based resin, and among them, it is preferable to use EPR (ethylene propylene rubber).
The "elastomer modification" may be achieved by graft polymerization of an elastomer, or by adding an elastomer to an olefin resin (homopolypropylene and/or the random copolymer), or may be another modification.

The random copolymer (layer) is a random copolymer containing "propylene" and "other copolymer components other than propylene" as copolymerization components. Regarding the random copolymer, the "other copolymer components other than propylene" are not particularly limited, and examples thereof include olefin components such as ethylene, 1-butene, 1-hexene, 1-pentene, and 4-methyl-1-pentene, as well as butadiene.

The thickness of the thermoplastic resin layer 3 is preferably set to 20 μm to 80 μm.
By setting the thickness to 80 μm or more, the occurrence of pinholes can be sufficiently prevented, and by setting the thickness to 80 μm or less, the amount of resin used can be reduced, thereby reducing costs. In particular, it is particularly preferable that the thickness of the thermoplastic resin layer 3 is set to 30 μm to 50 μm. The thermoplastic resin layer 3 may be a single layer or multiple layers.

[Metal foil layer]
The metal foil layer 4 plays a role of imparting gas barrier properties that prevent the intrusion of oxygen and moisture to the packaging material 1. The metal foil layer 4 is not particularly limited, but examples thereof include aluminum foil, copper foil, nickel foil, stainless steel foil, etc., and aluminum foil is generally used. As the aluminum foil, A8079H-O and A8021H-O as specified in JIS H4160-2006 are preferable. The thickness of the metal foil layer 4 is 20 μm.
It is preferable that the thickness is 20 μm or more to prevent the occurrence of pinholes during rolling in manufacturing the metal foil, and that the thickness is 100 μm or less to reduce stress during stretch forming or drawing, thereby improving formability.

It is preferable that at least the inner surface 4a (the surface on the inner adhesive layer 6 side) of the metal foil layer 4 is subjected to a chemical conversion treatment. By performing such a chemical conversion treatment, corrosion of the metal foil surface due to the contents (battery electrolyte, food, medicine, etc.) can be sufficiently prevented. For example, the chemical conversion treatment is performed on the metal foil by carrying out the following treatment. That is, for example, the surface of the metal foil that has been subjected to a degreasing treatment is subjected to the following treatment.
The chemical conversion treatment is carried out by applying and then drying one of the following: 1) an aqueous solution consisting of a mixture of phosphoric acid, chromic acid, and a metal salt of a fluoride; 2) an aqueous solution consisting of a mixture of phosphoric acid, chromic acid, a metal salt of a fluoride, and a non-metal salt of a fluoride; or 3) an aqueous solution consisting of a mixture of an acrylic resin and/or a phenolic resin, phosphoric acid, chromic acid, and a metal salt of a fluoride.

[Outer adhesive layer (first adhesive layer)]
The outer adhesive layer 5 is not particularly limited, but examples thereof include an adhesive layer formed from a two-component curing adhesive. The two-component curing adhesive is not particularly limited, but examples thereof include a two-component curing urethane adhesive and a two-component curing polyester urethane adhesive. The two-component curing urethane adhesive is not particularly limited, but examples thereof include a two-component curing urethane adhesive containing a polyol component and an isocyanate component. This two-component curing urethane adhesive is,
It is particularly suitable for use when bonding by a dry lamination method. The polyol component is not particularly limited, but examples thereof include polyester polyol and polyether polyol. The isocyanate component is not particularly limited, but examples thereof include diisocyanates such as TDI (tolylene diisocyanate), HMDI (hexamethylene diisocyanate), and MDI (methylene bis (4,1-phenylene) diisocyanate). The thickness of the outer adhesive layer 5 is preferably set to 2 μm to 5 μm, and particularly preferably set to 3 μm to 4 μm. The outer adhesive layer 5 may contain an inorganic or organic antiblocking agent or an amide slip agent.

The outer adhesive layer 5 is formed, for example, by applying an adhesive such as the two-component curing adhesive to the "upper surface of the metal foil layer 4" and/or to the "lower surface of the colored layer 9 laminated on the lower surface of the heat-resistant resin layer 2 via the easy-adhesion layer 8" by a method such as gravure coating. The method of forming the outer adhesive layer 5 is merely an example, and is not particularly limited to such a forming method.

[Inner adhesive layer (second adhesive layer)]
The inner adhesive layer 6 is an inner adhesive layer 5 that bonds the metal foil layer 4 and the sealant layer 3.
In order to prevent deterioration of the laminate strength over time due to the influence of the electrolyte, etc., at least the metal foil layer 4
It is preferable to use an adhesive resin having good adhesion to both the adhesive layer 2 and the sealant layer 3. The specific type of resin is not particularly limited, but examples thereof include resins obtained by graft-addition modification or copolymerization of dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid, and mesaconic acid, dicarboxylic anhydrides such as maleic anhydride, fumaric anhydride, itaconic anhydride, and mesaconic anhydride, and carboxyl group-containing monomers such as acrylic acid, methacrylic acid, crotonic acid, and itaconic acid to polypropylene. Among these, it is preferable to use a resin graft-addition modified with maleic anhydride, acrylic acid, or methacrylic acid, and maleic anhydride-modified polyolefin resin is particularly suitable. The method for producing such a resin is not particularly limited, but examples thereof include a solution method in which polypropylene is dissolved in an organic solvent and reacted with an acid (maleic anhydride, etc.) in the presence of a radical generator, and a melting method in which polypropylene is heated and melted and reacted with an acid (maleic anhydride, etc.) in the presence of a radical generator.

In addition, from the viewpoint of ensuring sufficient electrolyte resistance and thereby increasing the service life of the exterior material, it is particularly preferable that the inner adhesive layer 6 be composed of an adhesive composition containing a polyolefin resin having a carboxyl group in its chemical structure and a polyfunctional isocyanate compound.
This inner adhesive layer 6 can be formed, for example, by applying an adhesive liquid containing a polyolefin resin having a carboxyl group, a polyfunctional isocyanate compound, and an organic solvent to the metal foil layer 4 and/or the sealant layer 3, and then drying the liquid.

The polyolefin resin having a carboxyl group (hereinafter, sometimes referred to as a "carboxyl group-containing polyolefin resin") is not particularly limited, but examples thereof include:
Examples of the polyolefin include modified polyolefin resins obtained by graft-polymerizing an ethylenically unsaturated carboxylic acid or its acid anhydride to a polyolefin, and copolymer resins of an olefin monomer and an ethylenically unsaturated carboxylic acid. The polyolefin is not particularly limited, but examples thereof include homopolymers of olefin monomers such as ethylene, propylene, and butene, and copolymers of these olefin monomers. The ethylenically unsaturated carboxylic acid is,
Although not particularly limited, examples thereof include acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, etc. These ethylenically unsaturated carboxylic acids include
Only one type may be used, or two or more types may be used in combination. As the carboxyl group-containing polyolefin resin, one that is soluble in an organic solvent is preferably used.

Among them, it is preferable to use a modified polyolefin resin obtained by graft-polymerizing an ethylenically unsaturated carboxylic acid or its acid anhydride to a homopolymer of propylene or a copolymer of propylene and ethylene as the carboxyl group-containing polyolefin resin. The carboxyl group-containing polyolefin resin may be a single composition or may be a mixture of two polymers having different melting points.
It may be a mixture of more than one type.

The polyfunctional isocyanate compound reacts with the carboxyl group-containing polyolefin resin to act as a curing agent for curing the adhesive composition. The polyfunctional isocyanate compound is not particularly limited, but examples thereof include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, or isocyanurate-modified products of these diisocyanate compounds,
Examples of the polyfunctional isocyanate compound include biuret modified compounds, and modified compounds obtained by adduct-modifying the diisocyanate compound with a polyhydric alcohol such as trimethylolpropane. The polyfunctional isocyanate compound may be used alone or in combination of two or more. In addition, the polyfunctional isocyanate compound is preferably a polyfunctional isocyanate compound that dissolves in an organic solvent.

The organic solvent is not particularly limited as long as it can dissolve or disperse the carboxyl group-containing polyolefin resin. Among these, an organic solvent capable of dissolving the carboxyl group-containing polyolefin resin is preferably used. In addition, as the organic solvent, an organic solvent capable of easily removing the organic solvent from the adhesive liquid by heating or the like is preferably used. The organic solvent capable of dissolving the carboxyl group-containing polyolefin resin and easily removing the organic solvent by heating or the like is not particularly limited, and examples thereof include aromatic organic solvents such as toluene and xylene, aliphatic organic solvents such as n-hexane, alicyclic organic solvents such as cyclohexane and methylcyclohexane (MCH), and ketone organic solvents such as methyl ethyl ketone (MEK). These organic solvents may be used alone or in combination of two or more.

In the adhesive liquid or the adhesive resin composition, the equivalent ratio [NCO]/[OH] of the isocyanate group of the polyfunctional isocyanate compound to the hydroxyl group constituting the carboxyl group of the carboxyl group-containing polyolefin resin is preferably set to 0.5 to 10.0. If set in such a range, an adhesive composition having excellent initial adhesive performance can be obtained, and the deterioration over time of the adhesive strength between the metal foil layer 4 and the sealant layer 3 due to the electrolyte of the battery can be sufficiently suppressed for a longer period of time, thereby further improving the electrolyte resistance performance. The equivalent ratio [NCO]/[OH] is more preferably set to 1.0 to 9.0, and particularly preferably set to 1.0 to 6.0.

The adhesive liquid or adhesive composition may contain additives such as a reaction accelerator, a tackifier, a plasticizer, etc., as required.

The thickness of the inner adhesive layer 6 is preferably set to 1 μm to 10 μm. A thickness of 1 μm or more can provide sufficient adhesive strength, while a thickness of 10 μm or less can improve water vapor barrier properties.

In the above embodiment, a configuration is adopted in which the easy-adhesion layer 8, the colored layer 9, the first adhesive layer 5, and the second adhesive layer 6 are provided, but none of these layers are essential constituent layers, and a configuration in which they are not provided can also be adopted.

The exterior material 1 for an electricity storage device of the present invention can be molded (deep drawing, stretch molding, etc.) to obtain an exterior case 10 for an electricity storage device (see FIG. 3). The exterior material 1 of the present invention can also be used as it is without being molded (see FIG. 3).

FIG. 2 shows an embodiment of an electricity storage device 30 constructed using the exterior material 1 of the present invention. This electricity storage device 30 is a lithium ion secondary battery. In this embodiment, as shown in FIGS. 2 and 3, an exterior member 15 is constructed by an exterior case 10 obtained by molding the exterior material 1 and a planar exterior material 1 that was not used for molding. Thus, a substantially rectangular parallelepiped electricity storage device main body portion (electrochemical element, etc.) 31 is housed in the housing recess of the exterior case 10 obtained by molding the exterior material 1 of the present invention, and the exterior material 1 of the present invention is placed on the electricity storage device main body portion 31 with its inner layer 3 side facing inward (lower side) without being molded, and the peripheral portion of the inner layer 3 of the planar exterior material 1 and the inner layer 3 of the flange portion (sealing peripheral portion) 29 of the exterior case 10 are in contact with each other.
The above components are heat-sealed to form the electricity storage device 30 of the present invention (see Figs. 2 and 3). The inner surface of the storage recess of the exterior case 10 is an inner layer (sealant layer) 3, and the outer surface of the storage recess is a protective layer 7 (see Fig. 3).

In FIG. 2, 39 is a portion between the peripheral edge of the exterior material 1 and the flange portion of the exterior case 10 (
The heat seal portion is formed by joining (fusing) the sealing peripheral portion 29 to the power storage device 30. Note that in the power storage device 30, the tip portion of the tab lead connected to the power storage device main body 31 is led out to the outside of the exterior member 15, but is not shown in the figure.

The electric storage device main body 31 is not particularly limited, but examples thereof include a battery main body, a capacitor main body, and a condenser main body.

The width of the heat-sealed portion 39 is preferably set to 0.5 mm or more.
In particular, it is preferable that the width of the heat-sealed portion 39 is set to 3 mm to 15 mm.

In the above embodiment, the exterior member 15 includes the exterior case 10 obtained by molding the exterior material 1,
In the above embodiment, the exterior member 15 is configured to be composed of a pair of exterior materials 1 and a planar exterior case 10 (see Figures 2 and 3), but is not limited to this combination. For example, the exterior member 15 may be configured to be composed of a pair of exterior materials 1, or a pair of exterior cases 10.

Next, specific examples of the present invention will be described, but the present invention is not particularly limited to these examples.

Example 1
A base material was obtained by blending 50 parts by mass of carbon black having an average particle size of 0.8 μm, 5 parts by mass of ethylenediamine, and 45 parts by mass of polyester polyol (number average molecular weight: 2500). 3 parts by mass of tolylene diisocyanate (TDI) as a curing agent was blended with 100 parts by mass of the base material, and 50 parts by mass of toluene was further blended and thoroughly stirred to obtain an ink composition.

In addition, 70 parts by mass of "Takelac W-6010" manufactured by Mitsui Chemicals, Inc. was used as a water-based urethane resin, and "Denacol EX-521" manufactured by Nagase Chemtec Corporation was used as a water-based epoxy resin.
As an anti-blocking agent, 30 parts by mass of "Snowtex ST-C" colloidal silica (average particle size 10 nm to 20 nm) manufactured by Nissan Chemical Industries, Ltd. was mixed, and the mixture was further diluted with ion exchanged water to obtain an adhesive composition for forming an easy-adhesion layer having a non-volatile content of 2 mass%.

Next, a biaxially oriented nylon (6 nylon) film (heat-resistant resin oriented film layer, MD/TD=0.9) having a thickness of 15 μm and a hot water shrinkage rate of 4.0% was obtained by simultaneous biaxial stretching.
5) The adhesive composition for forming an easy-adhesion layer is applied to one surface of 2 by a gravure roll coating method, dried, and then allowed to stand in a 40° C. environment for one day to allow a curing reaction to proceed;
An easy-adhesion layer 8 having a formation amount of 0.1 g/m ² was formed.

Next, the ink composition was printed (applied) on the surface of the easy-adhesion layer 8 of the biaxially oriented nylon film 2 by gravure printing, and then left to stand for one day in a 40°C environment to allow drying and a crosslinking reaction to proceed, thereby forming a colored layer (black ink layer) 9 having a thickness of 3 μm, thereby obtaining a first laminate.

Further, on the biaxially oriented nylon film 2 of the first laminate (on the unlaminated surface), 55 parts by mass of a polyester (number average molecular weight: 5,300) having hydroxyl groups at both ends in the longitudinal direction of the main chain,
The mixture was mixed with 13 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate (referred to as "adduct A" in the table), 2 parts by mass of powdered silica having an average particle size of 2 μm, 20 parts by mass of barium sulfate having an average particle size of 2 μm, 5 parts by mass of acrylic resin beads having an average particle size of 7 μm, 5 parts by mass of polyethylene wax, and 100 parts by mass of a solvent (50 parts by mass of methyl ethyl ketone:
After coating the protective layer-forming composition, which is made of 50 parts by mass of toluene and 50 parts by mass of toluene, the composition is left in a 60° C. environment for 3 days to allow the reaction to proceed, forming a protective layer 7 having a thickness of 2 μm, and thus obtaining a second laminate.
was 2.9.

On the other hand, a chemical conversion treatment solution consisting of polyacrylic acid, phosphoric acid, a trivalent chromium compound, water, and alcohol was applied to both sides of an aluminum foil 4 having a thickness of 35 μm, and dried at 180° C. until the amount of chromium deposition became 5 mg/m ² .

Next, the second laminate is laminated on one side of the chemically treated aluminum foil 4 with a polyester polyurethane adhesive 5 interposed therebetween at its colored layer (black ink layer) 9 side, and then a 30 μm-thick unstretched polypropylene film (thermoplastic resin layer) 3 is laminated on the other side of the aluminum foil 4 with a maleic anhydride-modified polypropylene adhesive 6 interposed therebetween.
The product was left in an environment of 0° C. for 5 days, thereby obtaining an outer casing material 1 for an electricity storage device as shown in FIG. 1 .

Example 2
In the composition for forming the protective layer, "55 parts by mass of polyester having hydroxyl groups at both ends in the length direction of the main chain (number average molecular weight: 5300), 13 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate" was changed to "63 parts by mass of polyester having hydroxyl groups at both ends in the length direction of the main chain (number average molecular weight: 9800), 5 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate", and the equivalent ratio [NCO] was changed to
An exterior material for a power storage device 1 shown in FIG. 1 was obtained in the same manner as in Example 1, except that a composition for forming a protective layer having a molecular weight ratio of 1.8 was used.

Example 3
An outer casing material 1 for a storage battery device shown in FIG. 1 was obtained in the same manner as in Example 2, except that a composition for forming a protective layer in which erucic acid amide was further added at a concentration of 5000 ppm to the composition for forming a protective layer in Example 2 was used.

Example 4
In the composition for forming the protective layer, "55 parts by mass of a polyester having hydroxyl groups at both ends in the length direction of the main chain (number average molecular weight: 5,300), and 13 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate" was changed to "65 parts by mass of a polyester having hydroxyl groups at both ends in the length direction of the main chain (number average molecular weight: 14,500), and 3 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate", and the equivalent ratio [NCO]/
An exterior material for a power storage device 1 shown in FIG. 1 was obtained in the same manner as in Example 1, except that a composition for forming a protective layer having an [OH+COOH] of 1.6 was used.

Example 5
An exterior material for a power storage device 1 shown in FIG. 1 was obtained in the same manner as in Example 4, except that in the protective layer-forming composition, "3 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate" was changed to "1.5 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate and 1.5 parts by mass of an adduct of trimethylolpropane and tolylene diisocyanate (TDI)."

Example 6
In the composition for forming the protective layer, "55 parts by mass of a polyester having hydroxyl groups at both ends in the longitudinal direction of the main chain (number average molecular weight: 5,300), and 13 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate" was changed to "65 parts by mass of a polyester having hydroxyl groups at both ends in the longitudinal direction of the main chain (number average molecular weight: 14,500), and 3 parts by mass of an adduct of pentaerythritol and hexamethylene diisocyanate", and the equivalent ratio [NCO]/[
An exterior material 1 for an electricity storage device shown in FIG. 1 was obtained in the same manner as in Example 1, except that a composition for forming a protective layer having a molecular weight ratio (OH+COOH) of 1.7 was used.

Example 7
Polyester having hydroxyl groups at both ends of the main chain (number average molecular weight: 14,500)
Instead of the above, a polyester having hydroxyl groups at both ends of the main chain in the longitudinal direction (number average molecular weight: 19
An outer casing material for an electricity storage device 1 shown in FIG. 1 was obtained in the same manner as in Example 4, except that a cellulose acylate 110 (600) was used.

Example 8
Polyester having hydroxyl groups at both ends of the main chain (number average molecular weight: 14,500)
Instead of the above, a polyester having hydroxyl groups at both ends of the main chain in the longitudinal direction (number average molecular weight: 28
An outer casing material for an electricity storage device 1 shown in FIG. 1 was obtained in the same manner as in Example 4, except that 500g of ethylenediaminetetraacetate was used.

Example 9
Instead of a polyester having hydroxyl groups at both ends of the main chain in the length direction (number average molecular weight: 5300), a polyester having hydroxyl groups at both ends of the main chain in the length direction (number average molecular weight: 490
1 was obtained in the same manner as in Example 1, except that 1,000,000 cellulose ester was used.

Example 10
An outer casing material 1 for a storage battery device shown in FIG. 1 was obtained in the same manner as in Example 3, except that a polyester having carboxyl groups at both ends in the longitudinal direction of the main chain (number average molecular weight: 9800) was used instead of a polyester having hydroxyl groups at both ends in the longitudinal direction of the main chain (number average molecular weight: 9800).

Example 11
As a composition for forming a protective layer, a polyester having hydroxyl groups at both ends in the longitudinal direction of the main chain (
The electrical storage device exterior material 1 shown in FIG. 1 was produced in the same manner as in Example 2, except that a protective layer-forming composition was used that consisted of 57 parts by mass of a cellulose acylate copolymer (number average molecular weight: 9800), 10 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate, 1 part by mass of trimethylolpropane (polyhydric alcohol), 2 parts by mass of powdered silica having an average particle size of 2 μm, 20 parts by mass of barium sulfate having an average particle size of 2 μm, 5 parts by mass of acrylic resin beads having an average particle size of 7 μm, and 5 parts by mass of wax.
obtained.

Example 12
As a composition for forming a protective layer, a polyester having hydroxyl groups at both ends in the longitudinal direction of the main chain (
Number average molecular weight: 9800) 57 parts by mass, adduct of trimethylolpropane and hexamethylene diisocyanate 10 parts by mass, pentaerythritol (polyhydric alcohol) 1 part by mass, powdered silica having an average particle size of 2 μm 2 parts by mass, barium sulfate having an average particle size of 2 μm 20 parts by mass,
An exterior material 1 for a power storage device shown in FIG. 1 was obtained in the same manner as in Example 2, except that a composition for forming a protective layer consisting of 5 parts by mass of acrylic resin beads having an average particle size of 7 μm and 5 parts by mass of wax was used.

Example 13
As a composition for forming a protective layer, a polyester having hydroxyl groups at both ends in the longitudinal direction of the main chain (
Number average molecular weight: 9800) 57 parts by weight, adduct of trimethylolpropane and hexamethylene diisocyanate 10 parts by weight, glycerin (polyhydric alcohol) 1 part by weight, powdered silica having an average particle size of 2 μm 2 parts by weight, barium sulfate having an average particle size of 2 μm 20 parts by weight,
An exterior material for a power storage device 1 shown in FIG. 1 was obtained in the same manner as in Example 2, except that a protective layer-forming composition consisting of 5 parts by mass of acrylic resin beads having a diameter of 1 μm and 5 parts by mass of wax was used.

<Example 14>
In the protective layer-forming composition, "55 parts by mass of a polyester (number average molecular weight: 5,300) having hydroxyl groups at both ends in the length direction of the main chain, and 13 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate" was changed to "65 parts by mass of a polyester (number average molecular weight: 14,200) having four hydroxyl groups including the hydroxyl groups at both ends in the length direction of the main chain (having hydroxyl groups at both ends in the length direction of the main chain and having two hydroxyl groups at intermediate positions in the chain of the main chain), and 3 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate" and a protective layer-forming composition having an equivalent ratio [NCO]/[OH+COOH] of 0.8 was used. Except for this, an exterior material for a storage battery device 1 shown in FIG. 1 was obtained in the same manner as in Example 1.

Example 15
In the protective layer-forming composition, "55 parts by mass of a polyester (number average molecular weight: 5,300) having hydroxyl groups at both ends in the length direction of the main chain, and 13 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate" was changed to "65 parts by mass of a polyester (number average molecular weight: 11,200) having four hydroxyl groups including the hydroxyl groups at both ends in the length direction of the main chain (having hydroxyl groups at both ends in the length direction of the main chain and having two hydroxyl groups at intermediate positions in the chain of the main chain) and 3 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate" and a protective layer-forming composition having an equivalent ratio [NCO]/[OH+COOH] of 0.9 was used. Except for this, an exterior material for a storage battery device 1 shown in FIG. 1 was obtained in the same manner as in Example 1.

<Comparative Example 1>
As a composition for forming a protective layer, 65% of fluorine-containing polyol (number average molecular weight: 15,000) was used.
The electrical storage device exterior material 1 shown in FIG. 1 was produced in the same manner as in Example 1, except that a protective layer-forming composition was used, which consisted of 1 part by mass of 10 parts by mass of 100 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate, 3 parts by mass of a trimethylolpropane-hexamethylene diisocyanate adduct, 2 parts by mass of powdered silica having an average particle size of 2 μm, 20 parts by mass of barium sulfate having an average particle size of 2 μm, 5 parts by mass of acrylic resin beads having an average particle size of 7 μm, and 5 parts by mass of wax.
obtained.

<Comparative Example 2>
As a composition for forming a protective layer, 53% polyurethane polyol (number average molecular weight: 5400) was used.
parts by weight, adduct of trimethylolpropane and hexamethylene diisocyanate 15
An exterior material 1 for a storage battery device shown in FIG. 1 was obtained in the same manner as in Example 1, except that a protective layer-forming composition consisting of 2 parts by mass of powdered silica having an average particle size of 2 μm, 20 parts by mass of barium sulfate having an average particle size of 2 μm, 5 parts by mass of acrylic resin beads having an average particle size of 7 μm, and 5 parts by mass of wax was used.

<Comparative Example 3>
Except for using a protective layer-forming composition consisting of 53 parts by mass of acrylic polyol (number average molecular weight: 3400), 15 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate, 2 parts by mass of powdered silica having an average particle size of 2 μm, 20 parts by mass of barium sulfate having an average particle size of 2 μm, 5 parts by mass of acrylic resin beads having an average particle size of 7 μm, and 5 parts by mass of wax, an exterior material 1 for a power storage device shown in FIG. 1 was produced in the same manner as in Example 1.
obtained.

<Comparative Example 4>
In the composition for forming the protective layer, "55 parts by mass of a polyester having hydroxyl groups at both ends in the length direction of the main chain (number average molecular weight: 5,300), and 13 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate" was changed to "53 parts by mass of a polyester having hydroxyl groups at both ends in the length direction of the main chain (number average molecular weight: 3,900), and 15 parts by mass of an adduct of pentaerythritol and hexamethylene diisocyanate", and the equivalent ratio [NCO]/[
An exterior material for a power storage device 1 shown in FIG. 1 was obtained in the same manner as in Example 1, except that a composition for forming a protective layer having a molecular weight ratio (OH+COOH) of 2.6 was used.

<Comparative Example 5>
The same procedure as in Example 1 was repeated, except that in the protective layer-forming composition, "13 parts by mass of an adduct of trimethylolpropane and hexamethylene diisocyanate" was changed to "13 parts by mass of an adduct of trimethylolpropane and tolylene diisocyanate (TDI)."
An exterior material for an electricity storage device 1 shown in FIG. 1 was obtained.

In the table, trimethylolpropane and hexamethylene diisocyanate (H
An adduct between pentaerythritol and hexamethylene diisocyanate (HMDI) was denoted as "adduct A," an adduct between pentaerythritol and hexamethylene diisocyanate (HMDI) was denoted as "adduct B," and an adduct between trimethylolpropane and tolylene diisocyanate (TDI) was denoted as "adduct C."

Each of the electrical storage device exterior materials obtained as described above was evaluated according to the following evaluation methods. The results are shown in Tables 1 to 3.

<Moldability evaluation method>
Using an expansion molding machine manufactured by Amada Corporation (product number: TP-25C-X2), the exterior material for an electricity storage device was expanded into a rectangular parallelepiped shape of 55 mm in length × 35 mm in width × 8 mm in depth, and the formability was evaluated based on the following criteria.
(Judgment criteria)
"◎": No pinholes or cracks were observed.
"◯": No pinholes or cracks, but slight cloudiness is observed in the protective layer.
"△": A few pinholes were generated in a very small area, but practically none were generated.
"X": Pinholes and cracks occurred in the corners.

<Printability evaluation method>
A barcode (dot size: diameter 0.25 mm) was printed with white ink on the surface (outer surface) of the protective layer of each exterior material using an inkjet printer. Next, printability was evaluated based on the following criteria in terms of whether the printed barcode could be read without problems with a barcode reader and whether the printed barcode was blurred.
(Judgment criteria)
"◎": The barcode could be read without any problems using a barcode reader. There was no bleeding.
"○": The barcode can be read without any problems using a barcode reader. There is a slight blur, but it is not a problem.
"△": Some bleeding is observed, but the barcode can be read without any problems using a barcode reader.
"X": The barcode could not be read by the barcode reader. There was a large amount of bleeding.

<Solvent resistance evaluation method (ethanol)>
Each exterior material was cut into a size of 10 cm length x 10 cm width to obtain a test piece, and 1 mL (1 cc) of ethanol was dropped onto the surface (outer surface) of the protective layer of the test piece.
The droplet-attached portion of the test piece was rubbed back and forth 10 times with a sliding member having a weight of 1.0 g wrapped around the surface of the weight and a cotton-wrapped sliding member. After the 10 times of rubbing, the appearance of the surface (outer surface) of the protective layer of the test piece was visually inspected, and the solvent resistance (ethanol) was evaluated based on the following criteria.
(Judgment criteria)
"◎": There was no change in appearance even after 10 round trips.
"○": There was no change in appearance from the first to the seventh round trips, but a change in appearance occurred after the eighth round trip.
"△": There was no change in appearance for the first to fourth round trips, but a change in appearance occurred after the fifth round trip.
"X": Appearance changed after one stroke (poor solvent resistance).

<Solvent resistance evaluation method (methyl ethyl ketone)>
Solvent resistance (methyl ethyl ketone) was evaluated in the same manner as in the solvent resistance evaluation method (ethanol) except that 1 mL of methyl ethyl ketone (MEK) was used instead of 1 mL of ethanol.
The evaluation criteria were the same as those for the solvent resistance evaluation method (ethanol).

As is clear from the table, the exterior packaging materials for electricity storage devices of Examples 1 to 15 of the present invention were excellent in moldability, had good printability, and also had excellent solvent resistance.

In contrast, Comparative Examples 1 to 5, which deviate from the range of the present invention, had the following problems. That is, the exterior material of Comparative Example 1 had poor printability. Also, the exterior materials of Comparative Examples 2 to 5 had poor printability.
The solvent resistance to MEK was extremely poor.

The exterior material for an electricity storage device according to the present invention and the exterior case for an electricity storage device according to the present invention are,
As a specific example,
Used as exterior materials or exterior cases for various types of electricity storage devices such as lithium secondary batteries (lithium ion batteries, lithium polymer batteries, etc.), lithium ion capacitors, electric double layer capacitors, all-solid-state batteries, etc. Examples of the electricity storage device according to the present invention include the various electricity storage devices exemplified above.

1... Exterior material for an electricity storage device 2... Base material layer 3... Sealant layer (inner layer)
4...Metal foil layer 5...First adhesive layer (outer adhesive layer)
6...Second adhesive layer (inner adhesive layer)
7: Protective layer 8: Easy-adhesion layer 9: Colored layer 10: Outer case for electricity storage device (molded body)
15... Exterior member 30... Electricity storage device 31... Electricity storage device main body

Claims (10)

The device includes an exterior member and a main body of the power storage device,
the exterior member includes a base layer made of a heat-resistant resin, a sealant layer as an inner layer, and a metal foil layer disposed between the base layer and the sealant layer,
The electricity storage device is characterized in that a protective layer is provided on the surface of the base material layer opposite to the metal foil layer, the protective layer containing 40 mass% or more of a polyester resin formed from a polyester polyol having a number average molecular weight of 5,000 to 50,000 and having a hydroxyl group or a carboxyl group, independently at least at both ends, a polyfunctional isocyanate curing agent including at least an aliphatic polyfunctional isocyanate compound, and an aliphatic compound having a plurality of functional groups in one molecule that can react with an isocyanate group. The electricity storage device according to claim 1, wherein the equivalent ratio [NCO]/[OH+COOH], which is the ratio of the number of moles of isocyanate groups of the polyfunctional isocyanate curing agent to the sum of the number of moles of the hydroxyl groups and the number of moles of the carboxyl groups, is 0.5 to 5. The electricity storage device according to claim 1 or 2, wherein the aliphatic polyfunctional isocyanate compound is at least one aliphatic polyfunctional isocyanate compound selected from the group consisting of an adduct between trimethylolpropane and an aliphatic diisocyanate compound and an adduct between pentaerythritol and an aliphatic diisocyanate compound. The electric storage device according to any one of claims 1 to 3, characterized in that the protective layer further contains solid fine particles. The electric storage device according to any one of claims 1 to 4, characterized in that a colored layer is further disposed on the exterior member. The electric storage device according to any one of claims 1 to 5, characterized in that the number average molecular weight is 11,200 to 49,000. The electricity storage device according to any one of claims 1 to 6, characterized in that the gloss value of the surface (outer surface) of the protective layer is 30% or less. The electricity storage device according to any one of claims 1 to 7, characterized in that the electricity storage device main body is at least one selected from the group consisting of lithium secondary batteries such as lithium ion batteries and lithium polymer batteries, lithium ion capacitors, electric double layer capacitors, and all-solid-state batteries. A method for manufacturing an electricity storage device including an exterior member and an electricity storage device main body, comprising:
the exterior member includes a base layer made of a heat-resistant resin, a sealant layer as an inner layer, and a metal foil layer disposed between the base layer and the sealant layer,
The method for producing an electricity storage device includes a step of obtaining an exterior member having a protective layer on a surface of the base material layer opposite to the metal foil layer , the protective layer containing 40 mass% or more of a polyester resin formed from a polyester polyol having a number average molecular weight of 5,000 to 50,000 and having a hydroxyl group or a carboxyl group, independently at least at both ends, a polyfunctional isocyanate curing agent including at least an aliphatic polyfunctional isocyanate compound, and an aliphatic compound having a plurality of functional groups in one molecule capable of reacting with an isocyanate group. a step of forming the exterior member to obtain an exterior case having a recessed portion;
accommodating the power storage device main body in the accommodating recess;
placing the unformed, planar exterior member on the power storage device main body;
a step of heat-sealing a peripheral portion of the planar exterior member and a peripheral portion of the exterior case;
The method for manufacturing an electricity storage device according to claim 9 , further comprising:

Images