JP2016015250A - Sheath material for power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheath material for a power storage device, which is superior in moldability and therefore hard to produce a defect such as a crack or pin hole in cold molding, and which has superior adhesiveness with tape after heat sealing.SOLUTION: A sheath material for a power storage device comprises: a base material layer; a first adhesion layer, a metal foil layer, a corrosion-proof processed layer, a second adhesion layer and a sealant layer which are stacked on the base material layer on one side thereof in turn; and a protection layer stacked on the base material layer on the other side. The protection layer includes a water-soluble polymer, an OH group crosslinker and a filler; the content of the filler is 10-45 mass% to the total mass of the protection layer. The protection layer has a thickness of 2-7 μm.

Description

  The present invention relates to an exterior material for an electricity storage device.

  As power storage devices used for mobile terminal devices such as mobile phones and laptop computers, video cameras, satellites, electric vehicles, etc., for example, lithium ion batteries that can be made ultra-thin and miniaturized are known. In such an electricity storage device, contents such as a positive electrode material, a negative electrode material, a separator, and an electrolyte solution are packaged by molding an electricity storage device exterior material (hereinafter simply referred to as “exterior material”) into a predetermined shape. Stored in the body. Conventionally, a metal can obtained by press-molding a metal plate or the like has been used as the exterior body. However, since the degree of freedom of shape is high and the weight can be easily reduced, a laminate film having an aluminum foil (for example, Laminate film type obtained by cold molding a substrate layer / first adhesive layer / aluminum foil layer / second adhesive layer / sealant layer) is widely used.

  An electricity storage device using a laminate film as an exterior material is to deep-draw the laminate film by cold forming to form a recess, accommodate the contents in the recess, and heat seal the peripheral edge by heat sealing. Manufactured by. As the concave portion is deepened, the storage capacity of the power storage device increases and the energy density increases. Therefore, for the base material layer of the exterior material, a polyamide film having excellent moldability, which does not easily generate cracks or pinholes even when the recess is deepened, is preferably used.

  However, even when a polyamide film is used for the base material layer, the concave portion may not be deepened if the surface of the polyamide film is not sufficiently slippery. In order to obtain the slipperiness of the surface of the base material layer, for example, an exterior material in which a mat varnish layer is formed on the surface of the base material layer and the upper surface of the base material layer is processed to a predetermined surface roughness is known (Patent Document). 1).

Japanese Patent No. 5110132

  By the way, when using an exterior material as disclosed in Patent Document 1, after heat-sealing the outer periphery of the exterior material in the electricity storage device manufacturing process, the heat-sealed portion is bent to the electricity storage device body side and fixed with an adhesive tape. do. Since the stress of returning to the original state is applied to the folded portion of the exterior material, the tape may be peeled off when the adhesive force between the adhesive tape and the mat varnish layer is low. When the heat seal part fixed by peeling off the adhesive tape is lifted, it becomes impossible to install the electricity storage device in a predetermined space in the precision instrument.

  An object of the present invention is to provide an exterior material for an electricity storage device having excellent moldability in which defects such as cracks and pinholes are unlikely to occur during cold molding, and further having excellent tape adhesion after heat sealing.

  The packaging material for an electricity storage device of the present invention includes a base material layer, a first adhesive layer, a metal foil layer, a corrosion prevention treatment layer, a second adhesive layer, and a sealant layer, which are sequentially laminated on one surface side of the base material layer. A protective layer laminated on the other surface side of the base material layer, the protective layer contains a water-soluble polymer, an OH group cross-linking agent and a filler, and the filler content is the total mass of the protective layer. It is an exterior material which is 10 mass% or more and 45 mass% or less as a reference | standard, and the thickness of a protective layer is 2 micrometers or more and 7 micrometers or less. Such an exterior material can exhibit both excellent moldability and excellent tape adhesion after heat sealing.

  In this invention, the average particle diameter of a filler is 0.01 micrometer or more and 4 micrometers or less, and the root mean square deviation roughness (Sq) before heat sealing in the surface on the opposite side to a base material layer of a protective layer is 0. It is preferably 1 μm or more and 3 μm or less, and the root mean square deviation roughness after heat sealing is preferably 0.05 μm or more and 2 μm or less. Thereby, the more excellent moldability and the adhesive force of a heat seal part and an adhesive tape are securable.

  The root mean square deviation roughness after heat sealing is preferably 80% or less of the root mean square deviation roughness before heat sealing. As a result, the heat seal portion becomes clear, and the adhesive tape can be applied straight along the side of the battery cell while using the heat seal mark as a guide.

  Moreover, it is preferable that content of a filler is 20 to 40 mass% on the basis of the total mass of a protective layer. This makes it easier to obtain the effects of the present invention.

  In addition, it is preferable that a sealant layer consists of polyolefin resin or acid-modified polyolefin resin. Thereby, heat-sealing property can be improved more.

  According to the present invention, the battery has excellent electrolyte resistance, excellent moldability such that cracks, pinholes and the like do not easily occur during cold forming, and excellent tape adhesion after heat sealing. A packaging material for a device can be provided. In addition, in the present invention, by appropriately adjusting the surface roughness of the protective layer, when fixing the heat seal portion with the adhesive tape, the position where the adhesive tape is applied becomes clear, and the adhesive tape is connected to the battery cell. It becomes easy to stick straight along the side.

It is sectional drawing which represents typically the structure of the exterior material for electrical storage devices which concerns on one Embodiment of this invention. It is a top view which shows the state by which the recessed part was provided in the exterior material for electrical storage devices which concerns on one Embodiment of this invention. It is process drawing for obtaining an electrical storage device using the exterior | packing material for electrical storage devices which concerns on one Embodiment of this invention.

  Hereinafter, an embodiment according to the present invention will be described with reference to FIG. As shown in FIG. 1, a power storage device exterior material 1 (hereinafter referred to as “exterior material 1”) of this embodiment is sequentially laminated on a base layer 12 and one surface side of the base layer 12. A first adhesive layer 13, a metal foil layer 14, a corrosion prevention treatment layer 15, a second adhesive layer 16 and a sealant layer 17, and a protective layer 11 laminated on the other surface side of the base material layer 12 are provided. When packaging the battery contents with the outer packaging material 1, the protective layer 11 becomes the outermost layer and the sealant layer 17 becomes the innermost layer. That is, the exterior material 1 is used with the protective layer 11 on the outside of the electricity storage device and the sealant layer 17 on the inside of the electricity storage device.

  Although the thickness of the exterior material 1 is not particularly limited, it is preferably 50 μm or more and 180 μm or less, more preferably 60 μm or more and 160 μm or less, from the viewpoint of achieving both good moldability and high volume energy density of the battery. .

[Protective layer 11]
The protective layer 11 protects the base material layer 12 and plays a role of suppressing the base material layer 12 from being deteriorated or damaged by the electrolytic solution.

  The protective layer 11 contains a water-soluble polymer, an OH group crosslinking agent, and a filler (specifically, one or more filler components selected from the group consisting of an organic filler and an inorganic filler). Thereby, the surface roughness of the surface of the protective layer 11 is controlled, and the slipperiness of the surface of the protective layer 11 is improved.

  Examples of water-soluble polymers include starch, protein, carboxymethyl cellulose, sodium polyacrylate, polyethylene oxide, polyvinyl pyrrolidone, modified polyvinyl acetal, polyvinyl alcohol, and the like. Alcohol is preferred.

  The degree of polymerization of polyvinyl alcohol is preferably 1000 or more and 3500 or less, and more preferably 1700 or more and 2400 or less. If the degree of polymerization of polyvinyl alcohol is not less than the lower limit, the stretchability will be improved and the moldability will be better, and if it is not more than the upper limit, the dispersibility of fillers, pigments, etc. will be better.

  The saponification degree of polyvinyl alcohol is preferably 80 or more, more preferably 95 or more. If the degree of saponification of polyvinyl alcohol is at least the lower limit, the heat resistance and water resistance will be good. In addition, since it is difficult to produce polyvinyl alcohol having a saponification degree of 100 or more, the saponification degree is preferably substantially less than 100.

  As the polyvinyl alcohol, modified polyvinyl alcohol into which a functional group such as a carboxyl group or a carbonyl group is introduced may be used.

  The content of the water-soluble polymer is preferably 48% by mass or more and 78% by mass or less based on the total mass (100% by mass) of the protective layer 11 in terms of obtaining excellent electrolytic solution resistance and scratch resistance. 50 mass% or more and 70 mass% or less are more preferable. If it is in the said content range, the effect by other components, such as a lubricant, an elastomer component, and a filler, will be easy to be acquired.

  Examples of the OH group crosslinking agent include dialdehyde, methylol compound, phenol compound, isocyanate, polyamidoamine epichlorohydrin, vinyl sulfone compound, organometallic compound, isobutylene-maleic anhydride copolymer and vinyl ether-maleic anhydride copolymer. Polycarboxylic acids are exemplified, and among them, vinyl ether-maleic anhydride copolymer is particularly preferable.

  The addition concentration of the OH group crosslinking agent is preferably 5% by mass or more and 40% by mass or less, and more preferably 10% by mass or more and 30% by mass or less with respect to the total mass (100% by mass) of the water-soluble polymer. If the concentration of the cross-linking agent is at least the lower limit, the heat resistance required when heat-sealing the outer packaging material 1 is easily obtained, and if it is less than the upper limit, the heat-sealing softens and the filler is in the water-soluble polymer. It is buried and moderate smoothness is easily obtained.

  The protective layer 11 preferably contains a lubricant or is provided on the surface (that is, the surface opposite to the base material layer 12). Thereby, the moldability of the exterior material 1 and a winding yield can be improved more.

  Examples of the lubricant include fatty acid amides (for example, oleic acid amide, erucic acid amide, stearic acid amide, behenic acid amide, ethylene bisoleic acid amide, ethylene biserucic acid amide), glycerin and the like. These lubricants may be used individually by 1 type, and may use 2 or more types together.

When a lubricant is contained in the protective layer 11, the content of the lubricant is preferably 0.5% by mass or more and 10% by mass or less, and preferably 1% by mass or more and 5% by mass or less, based on the total mass of the protective layer 11. More preferred. If it is in such content range, the slipperiness required for shaping | molding will be obtained, without impairing the adhesiveness to the base material layer 12. FIG. On the other hand, when a lubricant is applied to the surface of the protective layer 11, the applied amount is preferably 0.1 g / m ² or more and 5 g / m ² or less.

  Examples of the elastomer component include styrene, olefin, ester, soft vinyl, urethane, and amide. These elastomer components may be used individually by 1 type, and may use 2 or more types together.

  When the elastomer component is contained in the protective layer 11, the content of the elastomer component is preferably 5% by mass or more and 30% by mass or less, preferably 10% by mass or more and 20% by mass or less, based on the total mass of the protective layer 11. More preferred. If it is such a content range, the extensibility required for shaping | molding will be obtained, without heat resistance falling.

  As the organic filler, plastic powder or fine particles can be used. Examples of the plastic include acrylic, urethane, silicone resin, polyethylene, polystyrene, polycarbonate, vinyl chloride, vinylidene chloride, melamine and the like. 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. These fillers may be used individually by 1 type, and may use 2 or more types together.

  The content of the filler component in the total mass (100 mass%) of the protective layer 11 is 10 mass% or more and 45 mass% or less, but preferably 20 mass% or more and 40 mass% or less. When the content of the filler component is at least the lower limit value, an appropriate surface roughness is obtained and the slipperiness is improved. If the content is below the upper limit, the filler is buried in the water-soluble polymer at the time of heat sealing to obtain appropriate smoothness, and all fillers are covered with the water-soluble polymer and the OH group crosslinking agent. Therefore, high adhesion between the water-soluble polymer and the OH group crosslinking agent and the filler can be obtained.

  The average particle size of the filler is preferably from 0.01 μm to 4 μm, more preferably from 0.5 μm to 3.5 μm, and even more preferably from 1.5 μm to 3 μm. If the average particle diameter of the filler is not less than the lower limit, an appropriate surface roughness can be obtained and the slipperiness can be improved. Also, if the particle size is less than the upper limit value, the filler is buried in the water-soluble polymer during heat sealing to obtain appropriate smoothness, and the filler has a large surface area, so the water-soluble polymer and the OH group crosslinking agent. Strong adhesion between the filler and the filler is obtained. The average particle size is, for example, a particle size measurement software manufactured by MOUNTECH, Mac-ViewVer. 4 can be measured.

  The thickness of the protective layer 11 is 2 μm or more and 7 μm or less, but preferably 3 μm or more and 5 μm or less. If the thickness of the protective layer 11 is not less than the lower limit value, the scratch resistance and the electrolytic solution resistance will be good. If the thickness of the protective layer 11 is less than or equal to the upper limit value, an appropriate surface roughness is obtained and the slipperiness is improved. In the present embodiment, the thickness of each layer can be measured using, for example, a cross-sectional SEM.

  In the present embodiment, it is preferable to adjust the surface roughness (root mean square deviation roughness Sq) of the surface of the protective layer 11 opposite to the base material layer 12 to a predetermined range. This is because if the surface is rough, the slipping property at the time of molding is high and preferable, but the adhesive force when the tape is applied after the molding is likely to drop. On the other hand, if the surface is smooth, the OH groups of the resin come out on the surface when the tape is applied after molding, so it is easy to obtain adhesion without being disturbed by particles, but the slipping property at the time of molding tends to decrease. This is because there is a trade-off relationship. In addition, although the slip property at the time of shaping | molding improves by adding a lubricant to the protective layer 11, since the adhesive force at the time of sticking a tape falls, said trade-off cannot fully be eliminated.

  The surface roughness before and after heat sealing can be measured as follows. In the present embodiment, the following operation is performed on five randomly selected portions of the heat seal portion, and the average value is defined as the surface roughness of each heat seal portion (protective layer) before and after heat sealing.

  Sq before heat sealing: The surface of the protective layer is observed with a laser microscope (for example, OLS-4000, manufactured by OLYMPAS), and the value of Sq is measured. A 50 × objective lens is used for measurement, and the scanning mode is XYZ high precision. A Gaussian filter is used as the smoothing filter, and the cutoff values are λc = 80 μm, λs = none, and λf = none.

  Sq after heat sealing: 180 to 210 ° C., preferably using a heat seal bar heated to 190 to 200 ° C., with a surface pressure of 0.3 to 1.3 MPa, preferably 0.5 to 1.0 MPa, The exterior material 1 is heat sealed for 15 seconds, preferably 3 to 10 seconds. Thereafter, the place where the heat seal bar is in contact with the surface of the protective layer is observed with a laser microscope, and the value of Sq is measured. In addition, although there is no limitation in particular in a heat seal apparatus, the target engineering company make and TEHS-300 can be used, for example.

  In addition, Sq before heat sealing is preferably 0.1 μm or more and 3 μm or less, more preferably 0.5 μm or more and 2.5 μm or less in consideration of moldability. If Sq before heat sealing is at least the lower limit value, good slipperiness is obtained, and if it is not more than the upper limit value, the filler can be prevented from falling off.

  The Sq of the heat seal part after heat sealing is preferably 0.05 μm or more and 2 μm or less, more preferably 0.1 μm or more and 1.5 μm or less in consideration of the adhesiveness of the tape. If Sq after heat sealing is greater than or equal to the lower limit value, it is possible to sufficiently ensure realistic feasibility. This is because it is difficult to make Sq after heat sealing smaller than the lower limit. If Sq after heat sealing is less than or equal to the upper limit, the amount of functional group-rich water-soluble polymer and OH group cross-linking agent present on the surface of the exterior material in contact with the tape increases, and coarse unevenness decreases. Therefore, it becomes easy to obtain good tape adhesiveness that can sufficiently withstand the force of the folded heat seal portion to return.

  In addition, it is preferable that Sq of the heat seal part after heat sealing is 80% or less of Sq of the heat seal part before heat sealing, and it is more preferable that it is 60% or less. Thereby, since the boundary of the part which is not made into the heat-sealed part can be confirmed visually, an adhesive tape can be affixed on the basis of the boundary. Therefore, it is possible to apply a tape in a straight line and improve workability and appearance. The lower limit of the Sq ratio is not particularly limited, but the heat resistance of the protective layer must be reduced to form a protective layer having an Sq ratio that is too low. .

[Base material layer 12]
The base material layer 12 is preferably made of a polyamide (nylon) or polyester film having high strength, high elongation, and softness in order to form a thin and sharp shape. Furthermore, biaxially stretched nylon (ONy) is more preferable from the viewpoint of excellent puncture strength and impact strength.

  The thickness of the base material layer 12 is preferably set to 4 μm or more and 30 μm or less, and more preferably set to 10 μm or more and 25 μm or less. If the thickness of the base material layer 12 is equal to or more than the lower limit value, it becomes easy to suppress the breakage of the metal foil layer 14 at the location stretched by the molding process, and thus more excellent moldability can be obtained. On the other hand, if the thickness is equal to or less than the upper limit value, the contraction force of the base material layer 12 at the portion stretched by the molding process is not so large, and the shape after the molding process can be maintained.

[First adhesive layer 13]
The first adhesive layer 13 is a layer that bonds the base material layer 12 and the metal foil layer 14 together. The adhesive constituting the first adhesive layer 13 is 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 polyurethane adhesive is preferable. In addition, a polyurethane type adhesive can perform strong adhesion | attachment by advancing the reaction of the hydroxyl group of a main ingredient and the isocyanate group of a hardening | curing agent by performing aging for 4 days or more, for example after coating at 40 degreeC.

  The thickness of the first adhesive layer 13 is preferably set to 1 μm or more and 10 μm or less, more preferably 3 μm or more and 7 μm or less, from the viewpoint of adhesive strength, followability, workability, and the like.

[Metal foil layer 14]
As the metal foil layer 14, various metal foils made of aluminum, stainless steel, or the like can be used, and aluminum foil is preferable from the viewpoints 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 mass% or more and 9.0 mass% or less are preferable, and, as for content of iron in the aluminum foil (100 mass%) containing iron, 0.5 mass% or more and 2.0 mass% or less are more preferable. If the iron content is equal to or higher than the lower limit value, the outer packaging material 1 is superior in pinhole resistance and spreadability. If the iron content is less than or equal to the upper limit, the exterior material 1 is more flexible.

  The thickness of the metal foil layer 14 is preferably set to 9 μm or more and 200 μm or less, more preferably 15 μm or more and 100 μm or less from the viewpoint of barrier properties, pinhole resistance, and workability.

[Corrosion prevention treatment layer 15]
The corrosion prevention treatment layer 15 serves to suppress the corrosion of the metal foil layer 14 due to the electrolytic solution or hydrofluoric acid generated by the reaction between the electrolytic solution and moisture. Further, it plays a role of increasing the adhesion between the metal foil layer 14 and the second adhesive layer 16.

  The corrosion prevention treatment layer 15 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 14. FIG. Moreover, since the adhesive force of the metal foil layer 14 and the 2nd contact bonding layer 16 is strengthened by an anchor effect, the outstanding tolerance with respect to contents, such as electrolyte solution, is acquired. However, the corrosion prevention treatment layer 15 may be added between the first adhesive layer 13 and the metal foil layer 14 according to a required function.

  Examples of the coating film include coating films, chromates, phosphates, fluorides, and various thermosets formed by ceriazol treatment with a corrosion inhibitor 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. However, the corrosion prevention treatment layer 15 is not limited to the coating film as long as the corrosion resistance of the metal foil layer 14 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 15 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 15. The thickness of the corrosion prevention treatment layer 15 is preferably set to 10 nm or more and 5 μm or less, and more preferably set to 20 nm or more and 500 nm or less from the viewpoint of the corrosion prevention function and the function as an anchor.

[Second adhesive layer 16]
The second adhesive layer 16 is a layer that bonds the metal foil layer 14 on which the corrosion prevention treatment layer 15 is formed and the sealant layer 17. The packaging material 1 is roughly divided into a thermal laminate configuration and a dry laminate configuration depending on the adhesive component that constitutes the second adhesive layer 16.

  As an adhesive component constituting the second adhesive layer 16 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 resin has a polar group introduced into a part of the nonpolar polyolefin resin, for example, a nonpolar layer formed of a polyolefin resin film or the like is used as the sealant layer 17. In addition, when a layer having polarity is used as the corrosion prevention treatment layer 15, it is possible to firmly adhere to both of these layers. In addition, by using an acid-modified polyolefin resin, resistance to contents such as an electrolytic 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 16 is prevented. easy. The acid-modified polyolefin resin used for the second adhesive layer 16 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, and high density polyethylene; ethylene-α olefin copolymer; homo, block or random polypropylene; propylene-α olefin copolymer. Can be mentioned. In addition, a copolymer obtained by copolymerizing a polar molecule such as acrylic acid or methacrylic acid with the aforementioned one, a polymer such as a crosslinked polyolefin, and the like can also be used. Examples of the acid that modifies the polyolefin resin include carboxylic acid, epoxy compound, acid anhydride and the like, and maleic anhydride is preferable.

  In the case of a thermal laminate configuration, the second adhesive layer 16 can be formed by extruding the adhesive component with an extrusion device.

  In the case of a dry laminate configuration, examples of the adhesive component that constitutes the second adhesive layer 16 include the same two-component curable polyurethane adhesive as that described for the first adhesive layer 13. However, in that case, since the second adhesive layer 16 having a dry laminate structure has a highly hydrolyzable bonding portion such as an ester group or a urethane group, the second adhesive layer 16 has a heat laminate structure for applications that require higher reliability. The second adhesive layer 16 is preferable.

  For example, the second adhesive layer 16 having a dry laminate structure is coated with the adhesive component on the second corrosion prevention treatment layer 15 side of the metal foil layer 14, and the solvent is blown away in a drying furnace having a temperature equal to or higher than the volatilization temperature of the solvent. Can be formed.

  The thickness of the second adhesive layer 16 is preferably set to 1 μm or more and 20 μm or less, more preferably 3 μm or more and 10 μm or less, from the viewpoint of ensuring adhesion strength and suppressing film cracking.

[Sealant layer 17]
The sealant layer 17 is a layer that imparts a sealing property by heat sealing in the exterior material 1. Examples of the sealant layer 17 include a resin film made of a polyolefin resin or an acid-modified polyolefin resin obtained by graft-modifying a polyolefin resin with an acid such as maleic anhydride.

  Examples of the polyolefin resin include low density, medium density, and high density polyethylene; ethylene-α olefin copolymer; homo, block, or random polypropylene; propylene-α olefin copolymer; polymethylpentene, and the like. It is done. These polyolefin resin may be used individually by 1 type, and may use 2 or more types together.

  Examples of the acid that modifies the polyolefin resin include the same acids as those mentioned for the second adhesive layer 16.

  The sealant layer 17 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.

  The sealant layer 17 may contain various additives such as a flame retardant, slip agent, anti-blocking agent, antioxidant, light stabilizer, and tackifier.

  The thickness of the sealant layer 17 is preferably set to 10 μm or more and 100 μm or less, and more preferably set to 20 μm or more and 60 μm or less.

  The exterior material 1 may be one in which a sealant layer 17 is laminated by dry lamination. From the viewpoint of improving adhesiveness, the second adhesive layer 16 is made of an acid-modified polyolefin resin, and the sealant layer is formed by sandwich lamination or coextrusion method. It is preferable that 17 is laminated.

[Method for Manufacturing Exterior Material 1]
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 (1)-(4) is mentioned, for example.
Step (1) A step of forming a corrosion prevention treatment layer 15 on the metal foil layer 14.
Process (2) The process of bonding the base material layer 12 through the 1st contact bonding layer 13 on the opposite side to the side in which the corrosion prevention process layer 15 in the metal foil layer 14 was formed.
Step (3) A step of bonding the sealant layer 17 to the corrosion prevention treatment layer 15 side of the metal foil layer 14 via the second adhesive layer 16.
Process (4) The process of forming the protective layer 11 in the opposite side to the side in which the 1st contact bonding layer 13 of the base material layer 12 was formed.

(Process (1))
A corrosion prevention treatment agent is applied to one surface of the metal foil layer 14 and dried to form the corrosion prevention treatment layer 15. Examples of the anti-corrosion treatment agent include the above-described anti-corrosion treatment agent for ceriazole treatment and anti-corrosion treatment agent for chromate treatment. 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.

(Process (2))
The base material layer 12 is bonded to the side of the metal foil layer 14 opposite to the side on which the corrosion prevention treatment layer 15 is formed, using an adhesive that forms the first adhesive layer 13 by a technique such as dry lamination. In the step (2), an aging treatment (curing) may be performed in a range of 40 ° C. or higher and 100 ° C. or lower in order to promote adhesion.

(Process (3))
A second adhesive layer 16 is formed by extrusion sandwich lamination on the corrosion prevention treatment layer 15 side of the laminate in which the base material layer 12, the first adhesion layer 13, the metal foil layer 14, and the corrosion prevention treatment layer 15 are laminated in this order. Then, a resin film for forming the sealant layer 17 is bonded. The lamination of the sealant layer 17 may be a co-extrusion laminating method in which the second adhesive layer 16 and the sealant layer 17 are extruded together.

(Process (4))
The protective layer 11 is formed by applying and drying a water-soluble polymer treatment agent on the side of the base material layer 12 opposite to the side on which the first adhesive layer 13 is formed. As a water-soluble polymer processing agent, the polyvinyl alcohol aqueous solution containing the above-mentioned filler and crosslinking agent is mentioned, for example. The method for applying the water-soluble polymer treating agent is not particularly limited, and various methods such as gravure coating, reverse coating, roll coating, and bar coating can be adopted. In addition, when apply | coating a lubricant to the protective layer 11 surface, as the application method, a gravure coat is mentioned, for example.

  The exterior material 1 is obtained by the steps (1) to (4) described above. In addition, the process sequence of the manufacturing method of the cladding | exterior_material 1 is not limited to the method of implementing said (1)-(4) sequentially. For example, step (3) may be performed after performing step (4).

[Method of manufacturing power storage device]
Hereinafter, the manufacturing method of the electrical storage device using the exterior | packing material 1 of this embodiment is demonstrated.

  FIG. 2 is a plan view showing a state in which the recess 18 is provided in the packaging material 1 of the present embodiment, and such a state can be specifically obtained as follows. First, the exterior material 1 of this embodiment is prepared. Then, for example, using a pressing member having a rectangular pressure surface, a recess 18 (molding area) is provided by pressing a part of the exterior material 1 in the thickness direction from the front side of the paper (sealant layer 17) side. Can do. Here, by pressing the pressing position, that is, the concave portion 18 at a position deviated from the center of the exterior material 1 cut into a rectangular shape, an area that is not pressed after the molding process can be used as a lid for the concave portion 18.

  FIG. 3 is a process diagram for obtaining an electricity storage device using the exterior material 1 of the present embodiment. FIG. 3A is a cross-sectional view taken along III (a) -III (a) of FIG.

  FIG. 3B is a diagram in which heat sealing is performed in a state where the battery contents X are stored. Thereby, the battery contents X can be sealed using the exterior material 1. Specifically, the sealing can be performed as follows. First, the battery contents X such as the positive electrode, the separator, and the negative electrode are accommodated in the recess 18, and the exterior material 1 is folded back along BB ′ as shown in FIG. 2. Then, AA ′ and CC ′ are overlapped with each other so that the sealant layer 17 faces each other, and either two sides are heat sealed using a heat seal bar. Thereafter, in a vacuum state, an electrolyte is injected from the remaining one side, the remaining one side is heat-sealed, and the battery contents X are sealed.

  FIG. 3C is a view in which the heat seal part 19 is fixed with the adhesive tape 20. That is, after heat sealing, the heat sealing portion 19 is cut to a predetermined width and folded back along the side surface of the battery contents X. And it can fix with the adhesive tape 20 so that the folded heat-seal part 19 may be covered, and the electrical storage device which concerns on this embodiment by which the battery contents X were sealed using the exterior | packing material 1 can be obtained. In the present embodiment, if the thickness of the battery contents X is too thin, problems such as capacity and bending resistance are likely to occur, and if it is too thick, cracks tend to occur in the protective layer and the like when forming a deep squeeze. Therefore, the thickness is preferably about 1 to 8 mm. Therefore, it is preferable that the width of the heat seal portion 19 folded back along the side surface of the battery contents X is also cut to be about 1 to 8 mm.

  In addition, such a manufacturing method is only an example to the last, and the electrical storage device obtained using the exterior material for electrical storage devices of this embodiment is not limited to what was manufactured by the said method.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by the following description.

[Materials used]
The materials used in this example are shown below.
(Protective layer 11)

Coating film A-1: manufactured by Kuraray as a water-soluble polymer, 61% by mass of PVA117, manufactured by ISP as an OH group crosslinking agent, 9% by mass of GANTREZ AN-119, and an average particle diameter of 2 μm as a filler A coating film having a coating thickness of 3 μm and containing 30% by mass of J-4P.
Coating film A-2: manufactured by Kuraray Co., Ltd. as a water-soluble polymer, 57% by mass of PVA117, manufactured by ISP Co., Ltd. as an OH group crosslinking agent, 8% by mass of GANTREZ AN-119, and an acrylic filler having an average particle diameter of 1 μm as a filler A coating film containing 35% by mass and having a coating thickness of 3 μm.
Coating film A-3: Sekisui Plastics manufactured by Kuraray Co., Ltd. as a water-soluble polymer, 48% by mass of PVA117, manufactured by ISP Co., Ltd., 7% by mass of GANTREZ AN-119, and an average particle diameter of 2 μm as a filler A coating film having a coating thickness of 3 μm, containing 45% by mass of SSX-102 manufactured by Kogyo Co., Ltd.
Coating film A-4: Kuraray Co., Ltd. as a water-soluble polymer, 65% by mass of PVA117, manufactured by ISP as an OH group crosslinking agent, 10% by mass of GANTREZ AN-119, and an average particle diameter of 5 μm as a filler A coating film having a coating thickness of 3 μm containing 25% by mass of SSX-105 manufactured by Kogyo Co., Ltd.
Coating film A-5: Kuraray Co., Ltd. as a water-soluble polymer, 39% by mass of PVA117, manufactured by ISP as an OH group cross-linking agent, 6% by mass of GANTREZ AN-119, and an average particle diameter of 2 μm as a filler A coating film having a coating thickness of 3 μm, containing 55% by mass of SSX-102 manufactured by Kogyo Co., Ltd.
Coating film A-6: manufactured by Kuraray as water-soluble polymer, 56% by mass of PVA117, manufactured by ISP as OH group crosslinking agent, 9% by mass of GANTREZ AN-119, and Negami Industrial Co., Ltd. having an average particle diameter of 2 μm as a filler A coating film having a coating thickness of 8 μm, containing 35% by mass of J-4P.

(Base material layer 12)
Base material B-1: Biaxially stretched nylon (ONy) film (thickness 15 μm).

(First adhesive layer 13)
Adhesive C-1: Polyester urethane adhesive (thickness: 4 μm).

(Metal foil layer 14)
Metal foil D-1: Soft aluminum foil 8079 (Toyo Aluminum Co., Ltd., thickness 40 μm).

(Corrosion prevention treatment layer 15)
Treatment agent E-1: Treatment agent for coating ceriazole treatment (thickness 20 nm) mainly composed of cerium oxide, phosphate and acrylic resin.

(Second adhesive layer 16)
Adhesive F-1: Polypropylene resin graft-modified with maleic anhydride (trade name “Admer”, manufactured by Mitsui Chemicals, thickness 3 μm)

(Sealant layer 17)
Film G-1: An unstretched polypropylene film (thickness: 60 μm) having a corona-treated surface on the corrosion prevention treatment layer side.

[Production of exterior materials]
The treatment agent E-1 was applied to one surface of the metal foil D-1 to be the metal foil layer 14 and dried to form the corrosion prevention treatment layer 15. Next, the base material B-1 to be the base material layer 12 was bonded to the opposite surface of the corrosion prevention treatment layer 15 in the metal foil layer 14 by a dry laminating method using an adhesive C-1. Thereafter, aging was performed at 60 ° C. for 6 days. Next, the adhesive F-1 is extruded by an extrusion device to the corrosion prevention treatment layer 15 side of the obtained laminate to form the second adhesive layer 16, and the film G-1 is bonded and sandwiched. A sealant layer 17 was formed. Next, any one of the coating films A-1 to A-6 was applied to the surface of the base material layer 12 of the obtained laminate by gravure coating, and the protective layer 11 was formed to prepare an exterior material. .

[Evaluation of exterior materials]
The obtained exterior materials were evaluated in the following 1) to 3). The evaluation results are shown in Table 1.

1) Evaluation of surface roughness before and after heat sealing Each of the obtained exterior materials was cut into 60 mm × 120 mm, and was folded in two along the short side so that the sealant layer was inside.
Surface roughness before heat sealing (Sq1): The surface of the protective layer was observed with a laser microscope (OLS-4000, manufactured by OLYMPAS), and the value of root mean square deviation roughness (Sq1) was measured. A 50 × objective lens was used for the measurement, and the scanning mode was XYZ high precision. A Gaussian filter was used as the smoothing filter, and the cutoff values were λc = 80 μm, λs = none, and λf = none.
Surface roughness after heat sealing (Sq2): Using a 10 mm-wide heat seal bar heated to 190 ° C., the folded exterior material was heat sealed at a surface pressure of 0.5 MPa for 3 seconds. Thereafter, the heat-sealed portion of the protective layer (in contact with the heat seal bar) was observed with a laser microscope, and the root mean square deviation roughness (Sq2) was measured in the same manner as Sq1.
Sq ratio: Based on Sq1 and Sq2 measured as described above, the ratio of Sq2 to Sq1 was calculated as Sq2 / Sq1 × 100 (%).

2) Evaluation of Tape Adhesive Strength In 1) above, a polyimide tape (Nitto Denko, No. 360A, 53 μm thickness) cut to 5 mm × 100 mm was adhered to the surface of the protective layer in contact with the heat seal bar. Thermocompression bonding was performed with a roll at 0 ° C. Thereafter, a T-peeling test of the polyimide tape was performed with a tensile tester, and the tape adhesion was evaluated. The test piece was a dumbbell type having a width of 6 mm, the distance between chucks was 50 mm, and the tensile speed was 300 mm / min. The evaluation criteria were as follows.
“A”: Adhesive strength of 3 N / mm ² or more “B”: Adhesive strength of less than 3 N / mm ²

3) Evaluation of moldability (molding depth) The obtained exterior material is cut into a blank shape of 150 mm × 190 mm, and cold while changing the molding depth in a molding environment of room temperature 23 ° C. and dew point temperature −35 ° C. Molded and evaluated for moldability. 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 as a molding punch. . The evaluation criteria were as follows.
“A”: Deep drawing with a molding depth of 6 mm or more is possible without causing breakage and cracks.
“B”: Deep drawing with a molding depth of 4 mm or more and less than 6 mm is possible without causing breakage or cracks.
“C”: Breaking and cracking occur in deep drawing with a molding depth of less than 4 mm.

4) Evaluation of tape sticking property The obtained exterior material was heat-sealed by the method of 1), and the mountain-fold was made so as to cover the heat-sealed portion with an adhesive tape (468MP 200MP / 3M) cut into 20 mm × 60 mm. I pasted it. In order to confirm whether or not the adhesive tape was applied to the end of the exterior material 1 without deviation, the difference in the width of the adhesive tape was measured with a scale at both ends in the longitudinal direction of the applied adhesive tape. The evaluation criteria were as follows.
“A”: The difference in width of the adhesive tape at both ends is less than 1 mm.
“B”: The width difference between the adhesive tapes at both ends is 1 mm or more and less than 3 mm.

  As shown in Table 1, Examples 1, 2, and 3 were able to achieve the intended task.

  In Example 4, the intended problem could be achieved, but the filler was larger than 4 μm and the surface roughness after heat sealing (root mean square deviation roughness) was the surface roughness before heat sealing (root mean square). Since the deviation roughness was not less than 80%, the tape sticking property was slightly inferior.

  On the other hand, Comparative Example 1 could not achieve the intended problem because the filler content was too high.

  In Comparative Example 2, the intended problem could not be achieved because the protective layer was too thick.

DESCRIPTION OF SYMBOLS 1 ... Exterior material for electrical storage devices, 11 ... Protective layer, 12 ... Base material layer, 13 ... First adhesive layer, 14 ... Metal foil layer, 15 ... Corrosion prevention treatment layer, 16 ... Second adhesive layer, 17 ... Sealant layer , 18 ... concave portion, 19 ... heat seal portion, 20 ... adhesive tape.

Claims (5)

A base material layer, a first adhesive layer, a metal foil layer, a corrosion prevention treatment layer, a second adhesive layer and a sealant layer, which are sequentially laminated on one surface side of the base material layer, and the other surface of the base material layer A protective layer laminated on the side,
The protective layer contains a water-soluble polymer, an OH group crosslinking agent and a filler,
The filler content is 10% by mass or more and 45% by mass or less based on the total mass of the protective layer,
An exterior material for an electricity storage device, wherein the protective layer has a thickness of 2 µm to 7 µm.   The filler has an average particle diameter of 0.01 μm or more and 4 μm or less, and the root mean square deviation roughness (Sq) before heat sealing on the surface of the protective layer opposite to the base material layer is 0.1 μm. The exterior material for an electricity storage device according to claim 1, which is 3 μm or less and the root mean square deviation roughness after heat sealing is 0.05 μm or more and 2 μm or less.   The power storage device exterior material according to claim 2, wherein the root mean square deviation roughness after heat sealing is 80% or less of the root mean square deviation roughness before heat sealing.   The packaging material for an electricity storage device according to any one of claims 1 to 3, wherein a content of the filler is 20% by mass or more and 40% by mass or less based on the total mass of the protective layer.   The packaging material for an electricity storage device according to any one of claims 1 to 4, wherein the sealant layer is made of a polyolefin resin or an acid-modified polyolefin resin.

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