Exterior material for a power storage device, method for manufacturing the same, and power storage device

Abstract

To provide an exterior material for a power storage device that has a black appearance but has an excellent identification mark printed on its surface in a yellow room.SOLUTION: An exterior material for a power storage device with a black appearance includes a laminate including, in order from the outside, at least a base material layer, a barrier layer, and a heat-fusible resin layer, and the b* value in the L*a*b* color space of the reflected light measured from the outside of the laminate under the measurement conditions of a SCI method, field of view 10°, and light source F2 is -0.20 or less.

Description

Technical Field

[0001] The present disclosure relates to an exterior material for a power storage device, a method for manufacturing the same, and a power storage device.

Background Art

[0002] Conventionally, various types of power storage devices have been developed. In any power storage device, an exterior material is an essential member for sealing power storage device elements such as electrodes and electrolytes. Conventionally, metal exterior materials have been widely used as exterior materials for power storage devices.

[0003] On the other hand, in recent years, with the improvement in performance of electric vehicles, hybrid electric vehicles, personal computers, cameras, mobile phones, etc., power storage devices are required to have various shapes and to be thinned and lightened. However, conventionally widely used metal exterior materials for power storage devices have the drawbacks that it is difficult to follow the diversification of shapes and there is also a limit to weight reduction.

[0004] Therefore, in recent years, as an exterior material for a power storage device that can be easily processed into various shapes and can achieve thinning and weight reduction, a film-like laminate in which a base material layer / a barrier layer / a heat-sealable resin layer are sequentially laminated has been proposed (see, for example, Patent Document 1).

[0005] In such an exterior material for a power storage device, generally, a recess is formed by cold forming, power storage device elements such as electrodes and electrolytic solution are arranged in the space formed by the recess, and the heat-sealable resin layer is heat-sealed, whereby a power storage device in which the power storage device elements are housed inside the exterior material for a power storage device is obtained.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] For example, a power storage device such as a lithium-ion secondary battery may be required to be colored black in order to unify the appearance and color of a device such as an electrical device to be mounted (see, for example, Patent Document 2).

[0008] On the other hand, in the manufacturing process of a power storage device using an exterior material for a power storage device, an identification mark such as product information (for example, characters and numbers indicating a lot number, a barcode, a symbol, etc.) may be printed on the surface of the power storage device. By attaching an identification mark to the surface of the power storage device, for example, it is possible to distinguish between genuine and counterfeit products. Similarly, in the manufacturing process of the exterior material for a power storage device, an identification mark or the like may be printed on the outer surface.

[0009] However, as a result of investigations by the inventors of the present disclosure, it has been found that when the appearance of a power storage device or an exterior material for a power storage device is colored so as to exhibit black, there is a new problem that the discriminability of printed identification marks and the like decreases in these manufacturing processes and the like.

[0010] Specifically, in the manufacturing process of a power storage device or an exterior material for a power storage device, processing and inspection may be performed under a yellow light source such as in a yellow room. However, when an identification mark or the like is printed on a power storage device or an exterior material for a power storage device whose appearance is black, and processing and inspection are performed under the light source in the yellow room, the discriminability of the identification mark decreases, and there is a problem that product information and the like may not be accurately read.

[0011] Under such circumstances, the main object of the present disclosure is to provide an exterior material for a power storage device that has excellent discriminability of an identification mark printed on the surface under the light source in a yellow room, even though it is an exterior material for a power storage device whose appearance is black.

MEANS FOR SOLVING THE PROBLEMS

[0012] The inventors of the present disclosure have conducted intensive studies to solve the above problems. As a result, in an exterior material for a power storage device composed of a laminate including at least a base material layer, a barrier layer, and a heat-sealable resin layer in order from the outside, and having a black appearance, the L of the reflected light measured from the outside under predetermined conditions * a * b * the b value in the color space is set to be equal to or less than a predetermined value, so that among blacks, it is possible to adjust to a black exhibiting a bluish hue that is a complementary color of yellow in particular, and the discriminability of the identification label printed on the surface is enhanced in a yellow room or under the light source of an orange-yellow lamp (Na lamp). * The present disclosure has been completed by further studies based on these findings. That is, the present disclosure provides an invention in the following aspects.

[0013] The present disclosure has been completed by further studies based on these findings. That is, the present disclosure provides an invention in the following aspects. An exterior material for a power storage device having a black appearance, the exterior material for a power storage device is composed of a laminate including at least a base material layer, a barrier layer, and a heat-sealable resin layer in order from the outside, Under the measurement conditions of the SCI method, a viewing angle of 10°, and a light source F2, the L of the reflected light measured from the outside of the laminate * a * b * the b value in the color space * is -0.20 or less, an exterior material for a power storage device.

Effect of the Invention

[0014] According to the present disclosure, it is possible to provide an exterior material for a power storage device that has excellent discriminability of an identification label printed on the surface under the light source of a yellow room or an orange-yellow lamp (Na lamp), even though it is an exterior material for a power storage device having a black appearance. Further, according to the present disclosure, it is also possible to provide a manufacturing method of the exterior material for a power storage device and a power storage device using the exterior material for a power storage device.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0016] The exterior material for an electric storage device of the present disclosure is an exterior material for an electric storage device having a black appearance, and the exterior material for an electric storage device is composed of a laminate including at least a base material layer, a barrier layer, and a heat-sealable resin layer in order from the outside. Under the measurement conditions of the SCI method, a viewing angle of 10°, and a light source F2, the L of the reflected light measured from the outside * a * b * b value in the color space * is characterized by being -0.20 or less. According to the exterior material for an electric storage device of the present disclosure, by having the said structure, although it is an exterior material for an electric storage device having a black appearance, excellent discriminability of an identification label printed on the surface can be exhibited under a light source in a yellow room.

[0017] Hereinafter, the exterior material for an electric storage device of the present disclosure will be described in detail. In this specification, the numerical range indicated by "~" means "or more" and "or less". For example, the notation of 2~15 mm means 2 mm or more and 15 mm or less.

[0018] In addition, in the exterior material for a power storage device of the present disclosure, "the appearance exhibits black" means that it is recognized as black when the exterior material for a power storage device is observed with the naked eye from the outside. More specifically, the "black" in "the appearance exhibits black" is the L * a * b * (CIELAB) chromaticity coordinates, where the L * value is 40 or less, preferably 35 or less. Regarding the L * value as well, it is the one in the color space of the reflected light measured from the outside under the measurement conditions of the SCI method, a viewing angle of 10°, and a light source F2. Also, for black, in addition to the L * a * b * value, preferably, the a * value is in the range of -20 to +20, and more preferably in the range of -10 to +10. The exterior material for a power storage device of the present disclosure is characterized in that, in addition to the appearance exhibiting black, the b * value is -0.20 or less. * As described later, by adjusting the types and contents of additives and colorants contained in each layer (layers located outside the barrier layers such as the base material layer, adhesive layer, coloring layer, and surface coating layer) constituting the exterior material for a power storage device of the present disclosure, the composition of the layers located outside the barrier layer, and further the aging treatment conditions of the exterior material for a power storage device described later, etc., the appearance of the exterior material for a power storage device can be made black and the b

[0019] value etc. can be adjusted. It is preferable to adjust the b * value using at least black additives and colorants (for example, black pigments), but it is also possible to mix multiple types of additives and colorants other than black to make black and adjust the b * value. Also, among the layers constituting the exterior material for a power storage device of the present disclosure, a black additive and colorant are used in one layer, and additives and colorants other than black (for example, blue) are used in other layers, and the b * value can be adjusted by multiple layers. * value can also be adjusted.

[0020] The "yellow room" means a room in which light with a wavelength of 500 nm or less including ultraviolet light is cut off, and in this room, the light is visually recognized as yellow. The yellow room is generally provided, for example, in a clean room of a semiconductor factory for performing a photolithography process in which photosensitive substances are handled.

[0021] 1. Laminated Structure and Physical Properties of Exterior Material for Energy Storage Device The exterior material 10 for a power storage device of the present disclosure is composed of, for example, a laminate including a base material layer 1, a barrier layer 3, and a heat-sealable resin layer 4 in this order from the outside. In the exterior material 10 for a power storage device, the base material layer 1 is on the outermost layer side, and the heat-sealable resin layer 4 is on the innermost layer. When assembling a power storage device using the exterior material 10 for a power storage device and a power storage device element, the power storage device element is accommodated in a space formed by heat-sealing the peripheral portions in a state where the heat-sealable resin layers 4 of the exterior material 10 for a power storage device face each other. In the laminate constituting the exterior material 10 for a power storage device of the present disclosure, with the barrier layer 3 as a reference, the side of the heat-sealable resin layer 4 is the inner side with respect to the barrier layer 3, and the side of the base material layer 1 is the outer side with respect to the barrier layer 3.

[0022] The exterior material 10 for a power storage device may, for example, as shown in FIGS. 2 and 4 to 6, have an adhesive layer 2 between the base material layer 1 and the barrier layer 3 as needed for the purpose of enhancing the adhesiveness between these layers (furthermore, as will be described later, coloring the exterior material 10 for a power storage device). Also, for example, as shown in FIGS. 3 and 4, between the base material layer 1 and the barrier layer 3, a coloring layer 21 may be provided as needed for the purpose of coloring the exterior material 10 for a power storage device. Also, for example, as shown in FIGS. 5 and 6, an adhesive layer 5 may be provided between the barrier layer 3 and the heat-sealable resin layer 4 as needed for the purpose of enhancing the adhesiveness between these layers. Also, as shown in FIG. 6, a surface coating layer 6 or the like may be provided on the outside of the base material layer 1 (the side opposite to the heat-sealable resin layer 4) as needed.

[0023] The thickness of the laminate constituting the exterior material 10 for a power storage device is not particularly limited, but from the viewpoints of cost reduction, improvement of energy density, etc., it is preferably about 180 μm or less, about 155 μm or less, about 120 μm or less. Further, as the thickness of the laminate constituting the exterior material 10 for a power storage device, from the viewpoint of maintaining the function of the exterior material for a power storage device to protect the power storage device element, it is preferably about 35 μm or more, about 45 μm or more, about 60 μm or more. Further, regarding the preferable range of the thickness of the laminate constituting the exterior material 10 for a power storage device, for example, about 35 to 180 μm, about 35 to 155 μm, about 35 to 120 μm, about 45 to 180 μm, about 45 to 155 μm, about 45 to 120 μm, about 60 to 180 μm, about 60 to 155 μm, about 60 to 120 μm can be mentioned.

[0024] The exterior material 10 for a power storage device of the present disclosure has an L of reflected light measured from the outside under the measurement conditions of the SCI method, a viewing angle of 10°, and a light source F2. * a * b * b value in the color space * is -0.20 or less. By setting the upper limit of the b value to such a specific value, in the exterior material for a power storage device whose appearance is black, it is possible to adjust to black presenting a bluish hue which is the complementary color of yellow, and excellent discriminability of the identification label printed on the surface is exhibited in a yellow room or under a yellow light source. * *

[0025] b * The b value is not particularly limited as long as it is -0.20 or less, but from the viewpoints that the discriminability is further improved and the appearance is preferably recognized as black, it is preferably about -0.50 or less, more preferably about -0.80 or less. Further, from the same viewpoints, the b value is preferably about -5.00 or more, more preferably about -4.00 or more, still more preferably about -2.00 or more, and still more preferably about -1.50 or more. Also, the b * * *Preferred ranges of the value are about -5.00 to -0.20, about -5.00 to -0.50, about -5.00 to -0.80, about -4.00 to -0.20, about -4.00 to -0.50, about -4.00 to -0.80, about -2.00 to -0.20, about -2.00 to -0.50, about -2.00 to -0.80, about -1.50 to -0.20, about -1.50 to -0.50, about -1.50 to -0.80. Among these, b * The value is particularly preferably about -1.50 to -0.80.

[0026] Further, the exterior material 10 for the power storage device of the present disclosure has an L of reflected light measured from the outside under the measurement conditions of the SCI method, a visual field of 10°, and a light source F2 * a * b * The a value in the color space * is preferably 0.20 or less. Thereby, the discriminability is further improved, and it is preferably recognized that the appearance is black.

[0027] a * As the value, from the viewpoints of further improving the discriminability and preferably recognizing that the appearance is black, it is more preferably about 0.10 or less, still more preferably 0.04 or less, still more preferably about 0.02 or less, still more preferably about 0.00 or less, still more preferably about -0.01 or less. Also, from the same viewpoints, as the a * value, it is preferably about -3.50 or more, more preferably about -3.00 or more, still more preferably about -2.00 or more, still more preferably about -0.50 or more, still more preferably about -0.30 or more, still more preferably about -0.15 or more, still more preferably about -0.10 or more. Also, a *Preferred ranges of the value are about -3.50 to +0.20, about -3.50 to +0.10, about -3.50 to +0.04, about -3.50 to +0.02, about -3.50 to 0.00, about -3.50 to -0.01, about -3.00 to +0.20, about -3.00 to +0.10, about -3.00 to +0.04, about -3.00 to +0.02, about -3.00 to 0.00, about -3.00 to -0.01, about -2.00 to +0.20, about -2.00 to +0.10, about -2.00 to +0.04, about -2.00 to +0.02, about -2.00 to 0.00, about -2.00 to -0.01, about -0.50 to +0.20, about -0.50 to +0.10, about -0.50 to +0.04, about -0.50 to +0.02, about -0.50 to 0.00, about -0.50 to -0.01, about -0.30 to +0.20, about -0.30 to +0.10, about -0.30 to +0.04, about -0.30 to +0.02, about -0.30 to 0.00, about -0.30 to -0.01, about -0.15 to +0.20, about -0.15 to +0.10, about -0.15 to +0.04, about -0.15 to +0.02, about -0.15 to 0.00, about -0.15 to -0.01, about -0.10 to +0.20, about -0.10 to +0.10, about -0.10 to +0.04, about -0.10 to +0.02, about -0.10 to 0.00, about -0.10 to -0.01. Among these, a * The value is particularly preferably about -0.30 to -0.01 and about -0.10 to -0.01. [[ID=q4]]

[0028] In addition, the exterior material 10 for the power storage device of the present disclosure has an L of the reflected light measured from the outside under the measurement conditions of the SCI method, a viewing angle of 10°, and a light source F2. * a * b * L in the color space * The value is preferably 35.0 or less. Thereby, the discriminability is further improved, and it is preferably recognized that the appearance is black.

[0029] L *As values, from the viewpoint that the distinctiveness is further improved and the appearance is preferably recognized as black, more preferably about 33.0 or less, more preferably about 30.0 or less, and even more preferably about 28.0 or less. Also, from the same viewpoint, L * As values, preferably about 25.0 or more, more preferably about 26.0 or more. Also, L * Preferred ranges of the L value include about 25.0 to 35.0, about 25.0 to 33.0, about 25.0 to 30.0, about 25.0 to 28.0, about 26.0 to 35.0, about 26.0 to 33.0, about 26.0 to 30.0, about 26.0 to 28.0. Among these, L * The value is particularly preferably about 25.0 to 30.0, about 26.0 to 30.0, more preferably about 26.0 to 29.0, and even more preferably about 26.0 to 28.0.

[0030] <L * value, a * value and b * Measurement of values In the present disclosure, L * value, a * value and b * The values are the values measured by the following method. For the exterior material for a power storage device, the observation conditions of a spectrophotometer (for example, CM-700d manufactured by Konica Minolta) calibrated with a white calibration cap (for example, CM-A177: manufactured by Konica Minolta) are 10°, the observation light source is F2, SCI Set to the mode (JIS Z8722-2009), and measure L * , a * , b * on the outer surface (substrate layer side) at normal temperature and normal humidity. The measurement is performed by measuring three points for each sample, and the average value is taken as the measured value. Also, the L * value, a * value, and b * value can also be measured. When the exterior material for a power storage device is obtained from a power storage device and measured, the top surface where the exterior material for a power storage device is not stretched by molding is the measurement target.

[0031] In the exterior material for a power storage device of the present disclosure and in a power storage device using the same, examples of the identification mark to be printed include characters or numbers indicating a lot number, barcodes, symbols, and the like. Further, the color of the ink used for printing the identification mark (that is, the color of the identification mark) is preferably white in the exterior material for a power storage device of the present disclosure having a black appearance because it has excellent discriminability.

[0032] 2. Each Layer Forming Exterior Material for Energy Storage Device [Base material layer 1] In the present disclosure, the base material layer 1 is a layer provided for the purpose of, for example, exerting the function as a base material of the exterior material for a power storage device. The base material layer 1 is located on the outer layer side of the exterior material for a power storage device.

[0033] The material forming the base material layer 1 is not particularly limited as long as it has the function as a base material, that is, at least has insulation properties. The base material layer 1 can be formed using, for example, a resin, and the resin may contain additives described later. For example, by blending an additive or a colorant described later into the base material layer, the above-mentioned L * value, a * value and b * value can also be adjusted.

[0034] When the base material layer 1 is formed of a resin, the base material layer 1 may be, for example, a resin film formed of a resin, or may be formed by applying a resin. The resin film may be an unstretched film or a stretched film. Examples of the stretched film include a uniaxially stretched film and a biaxially stretched film, and a biaxially stretched film is preferred. Examples of the stretching method for forming the biaxially stretched film include a sequential biaxial stretching method, an inflation method, a simultaneous biaxial stretching method, and the like. Examples of the method for applying the resin include a roll coating method, a gravure coating method, an extrusion coating method, and the like.

[0035] Examples of the resin for forming the base material layer 1 include resins such as polyester, polyamide, polyolefin, epoxy resin, acrylic resin, fluororesin, polyurethane, silicone resin, and phenol resin, and modified products of these resins. Further, the resin for forming the base material layer 1 may be a copolymer of these resins, or a modified product of the copolymer. Furthermore, a mixture of these resins may also be used.

[0036] Among these, preferred examples of the resin for forming the base material layer 1 include polyester and polyamide.

[0037] Specific examples of the polyester include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, copolyester, etc. Examples of the copolyester include copolyesters having ethylene terephthalate as the main repeating unit. Specifically, copolyester polyesters obtained by polymerizing ethylene isophthalate with ethylene terephthalate as the main repeating unit (hereinafter abbreviated following polyethylene (terephthalate / isophthalate)), polyethylene (terephthalate / adipate), polyethylene (terephthalate / sodium sulfoisophthalate), polyethylene (terephthalate / sodium isophthalate), polyethylene (terephthalate / phenyl-dicarboxylate), polyethylene (terephthalate / decanedicarboxylate), etc. These polyesters may be used alone or in combination of two or more.

[0038] Also, examples of the polyamide include, specifically, aliphatic polyamides such as nylon 6, nylon 66, nylon 610, nylon 12, nylon 46, and copolymers of nylon 6 and nylon 66; hexamethylenediamine-isophthalic acid-terephthalic acid copolymer polyamides such as nylon 6I, nylon 6T, nylon 6IT, and nylon 6I6T (where I represents isophthalic acid and T represents terephthalic acid) that contain structural units derived from terephthalic acid and / or isophthalic acid, and polyamides containing aromatics such as polyamide MXD6 (polymetaxylylene adipamide); alicyclic polyamides such as polyamide PACM6 (poly(bis(4-aminocyclohexyl)methane adipamide)); furthermore, polyamides copolymerized with a lactam component or an isocyanate component such as 4,4'-diphenylmethane-diisocyanate, and polyester amide copolymers and polyether ester amide copolymers that are copolymers of a copolymer polyamide and a polyester or a polyalkylene ether glycol; and polyamides such as these copolymers. These polyamides may be used alone or in combination of two or more.

[0039] The base material layer 1 preferably contains at least one of a polyester film, a polyamide film, and a polyolefin film, more preferably contains at least one of a stretched polyester film, a stretched polyamide film, and a stretched polyolefin film, still more preferably contains at least one of a biaxially stretched polyethylene terephthalate film, a biaxially stretched polybutylene terephthalate film, a biaxially stretched nylon film, and a biaxially stretched polypropylene film.

[0040] The base material layer 1 may be a single layer or may be composed of two or more layers. When the base material layer 1 is composed of two or more layers, the base material layer 1 may be a laminate in which resin films are laminated with an adhesive or the like, or may be a laminate of resin films in which resins are co-extruded to form two or more layers. Further, the laminate of resin films in which resins are co-extruded to form two or more layers may be used as the base material layer 1 as it is without stretching, or may be uniaxially or biaxially stretched to be used as the base material layer 1.

[0041] In the base material layer 1, specific examples of the laminate of two or more resin films include a laminate of a polyester film and a nylon film, a laminate of two or more nylon films, a laminate of two or more polyester films, etc. Preferably, a laminate of a stretched nylon film and a stretched polyester film, a laminate of two or more stretched nylon films, and a laminate of two or more stretched polyester films are preferred. For example, when the base material layer 1 is a laminate of two resin films, a laminate of a polyester resin film and a polyester resin film, a laminate of a polyamide resin film and a polyamide resin film, or a laminate of a polyester resin film and a polyamide resin film is preferred, and a laminate of a polyethylene terephthalate film and a polyethylene terephthalate film, a laminate of nylon films, or a laminate of a polyethylene terephthalate film and a nylon film is more preferred. Further, since the polyester resin is less likely to change color when, for example, an electrolytic solution adheres to the surface, when the base material layer 1 is a laminate of two or more resin films, it is preferable that the polyester resin film is located on the outermost layer of the base material layer 1.

[0042] When the base material layer 1 is a laminate of two or more resin films, the two or more resin films may be laminated via an adhesive. Preferred adhesives include the same ones as those exemplified for the adhesive layer 2 described later. The method for laminating two or more resin films is not particularly limited, and known methods can be adopted. For example, dry lamination method, sandwich lamination method, extrusion lamination method, thermal lamination method, etc. can be mentioned, and preferably the dry lamination method can be mentioned. When laminating by the dry lamination method, it is preferable to use a polyurethane adhesive as the adhesive. At this time, the thickness of the adhesive is, for example, about 2 to 5 μm. Also, an anchor coat layer may be formed on and laminated to the resin film. The anchor coat layer includes the same ones as those exemplified for the adhesive layer 2 described later. At this time, the thickness of the anchor coat layer is, for example, about 0.01 to 1.0 μm.

[0043] In addition, additives such as lubricants, flame retardants, antiblocking agents, antioxidants, light stabilizers, tackifiers, antistatic agents, etc. may be present on at least one of the surface and inside of the base material layer 1. Only one type of additive may be used, or two or more types may be mixed and used.

[0044] In the present disclosure, from the viewpoint of enhancing the moldability of the exterior material for the power storage device, it is preferable that a lubricant is present on the surface of the base material layer 1. The lubricant is not particularly limited, but preferably an amide-based lubricant. Specific examples of the amide-based lubricant include, for example, saturated fatty acid amide, unsaturated fatty acid amide, substituted amide, methylol amide, saturated fatty acid bisamide, unsaturated fatty acid bisamide, fatty acid ester amide, aromatic bisamide, and the like. Specific examples of the saturated fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, and the like. Specific examples of the unsaturated fatty acid amide include oleic acid amide, erucic acid amide, and the like. Specific examples of the substituted amide include N-oleyl palmitic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, and the like. Specific examples of the methylol amide include methylol stearic acid amide, and the like. Specific examples of the saturated fatty acid bisamide include methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisstearic acid amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipic acid amide, N,N'-distearyl sebacic acid amide, and the like. Specific examples of the unsaturated fatty acid bisamide include ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N,N'-dioleyl adipic acid amide, N,N'-dioleyl sebacic acid amide, and the like. Specific examples of the fatty acid ester amide include stearoamide ethyl stearate, and the like. Specific examples of the aromatic bisamide include m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, N,N'-distearyl isophthalic acid amide, and the like. The lubricant may be used alone or in combination of two or more.

[0045] When a lubricant is present on the surface of the base material layer 1, the amount of its presence is not particularly limited, but preferably about 3 mg / m 2 or more, more preferably 4 to 15 mg / m 2 or so, even more preferably 5 to 14 mg / m 2 or so can be mentioned.

[0046] The lubricant present on the surface of the base material layer 1 may be one obtained by exuding the lubricant contained in the resin constituting the base material layer 1, or may be one obtained by applying a lubricant to the surface of the base material layer 1.

[0047] Regarding the thickness of the base material layer 1, there is no particular limitation as long as the function as a base material is exhibited. For example, it is about 3 to 50 μm, preferably about 10 to 35 μm. When the base material layer 1 is a laminate of two or more resin films, the thickness of each resin film constituting each layer is preferably about 2 to 25 μm.

[0048] For example, when the adhesive layer is a layer colored black, the base material layer located outside the adhesive layer is preferably transparent or translucent.

[0049] [Adhesive layer 2] In the exterior material for a power storage device of the present disclosure, the adhesive layer 2 is a layer provided between these as needed for the purpose of enhancing the adhesiveness between the base material layer 1 and the barrier layer 3.

[0050] Also, in the exterior material for a power storage device of the present disclosure, the adhesive layer 2 may be colored black. By coloring the adhesive layer 2 black, on the basis of obtaining an exterior material for a power storage device having a black appearance, the b * value can be suitably set to -0.20 or less. However, if the adhesive layer 2 is colored black, the b *It doesn't necessarily become -0.20 or less. By adjusting the composition such as the type and content of the colorant contained in the adhesive layer 2, the composition of the base material layer 1, the composition of the layers located outside the barrier layer 3 such as the surface coating layer 6 and the coloring layer 21 provided as needed, and further the aging treatment conditions of the exterior material for the power storage device described later, the appearance of the exterior material for the power storage device can be made black, and the b * value can be set to -0.20 or less 。L * value and a * The same applies to the setting of the value.

[0051] The adhesive layer 2 is formed of an adhesive that can bond the base material layer 1 and the barrier layer 3. The adhesive used for forming the adhesive layer 2 is not limited, and it may be any of a chemical reaction type, a solvent evaporation type, a hot melt type, a hot press type, etc. Also, it may be a two-component curing adhesive (two-component adhesive), a one-component curing adhesive (one-component adhesive), or a resin without a curing reaction. Further, the adhesive layer 2 may be a single layer or a multi-layer.

[0052] Specific examples of the adhesive component contained in the adhesive include polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolyester; polyethers; polyurethanes; epoxy resins; phenolic resins; polyamides such as nylon 6, nylon 66, nylon 12, and copolyamide; polyolefin resins such as polyolefin, cyclic polyolefin, acid-modified polyolefin, and acid-modified cyclic polyolefin; polyvinyl acetate; cellulose; (meth)acrylic resins; polyimides; polycarbonates; amino resins such as urea resin and melamine resin; rubbers such as chloroprene rubber, nitrile rubber, and styrene-butadiene rubber; and silicone resins. These adhesive components may be used alone or in combination of two or more. Among these adhesive components, polyurethane adhesives are preferably mentioned. In addition, the resins serving as these adhesive components can enhance the adhesive strength by using an appropriate curing agent in combination. The curing agent is appropriately selected from polyisocyanates, polyfunctional epoxy resins, oxazoline group-containing polymers, polyamine resins, acid anhydrides, etc., according to the functional groups of the adhesive components.

[0053] Examples of polyurethane adhesives include polyurethane adhesives containing a main agent containing a polyol compound and a curing agent containing an isocyanate compound. Preferably, a two-component curable polyurethane adhesive using a polyol such as polyester polyol, polyether polyol, or acrylic polyol as the main agent and an aromatic or aliphatic polyisocyanate as the curing agent can be mentioned. Further, as the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group not only at the terminal of the repeating unit but also in the side chain. Examples of the curing agent include aliphatic, alicyclic, aromatic, and araliphatic isocyanate compounds. Examples of the isocyanate compound include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthalene diisocyanate (NDI), and the like. Further, examples include polyfunctional isocyanate modified products derived from one or more of these diisocyanates. Further, a multimer (for example, a trimer) can also be used as the polyisocyanate compound. Examples of such multimers include adducts, biurets, and nurates. Note that the aliphatic isocyanate compound refers to an isocyanate having an aliphatic group and no aromatic ring, the alicyclic isocyanate compound refers to an isocyanate having an alicyclic hydrocarbon group, and the aromatic isocyanate compound refers to an isocyanate having an aromatic ring. Since the adhesive layer 2 is formed of a polyurethane adhesive, excellent electrolyte resistance is imparted to the exterior material for the power storage device, and even if the electrolyte adheres to the side surface, peeling of the base material layer 1 is suppressed.

[0054] In addition, as long as the adhesive property is not inhibited, the addition of other components is allowed in the adhesive layer 2, and it may contain a colorant, a thermoplastic elastomer, a tackifier, a filler, and the like. Since the adhesive layer 2 contains a colorant, the exterior material for the power storage device can be colored. As the colorant, known ones such as pigments and dyes can be used. Also, only one type of colorant may be used, or two or more types may be mixed and used.

[0055] The type of the pigment is the above-mentioned b * As long as the value is -0.20 or less and the adhesiveness of the adhesive layer 2 is not impaired, it is not particularly limited. Examples of the organic pigment include pigments such as azo-based, phthalocyanine-based, quinacridone-based, anthraquinone-based, dioxazine-based, indigothioindigo-based, perinone-perylene-based, isoindolenine-based, and benzimidazolone-based pigments. Examples of the inorganic pigment include pigments such as carbon black-based, titanium-based, titanium oxide-based, cadmium-based, lead-based, chromium oxide-based, and iron-based pigments. In addition, fine powders of mica (muscovite), fish scale foil, and the like can be mentioned.

[0056] The average particle diameter of the pigment is the above-mentioned b * As long as the value is -0.20 or less and the adhesiveness of the adhesive layer 2 is not impaired, it is not particularly limited. For example, it is about 0.05 to 5 μm, preferably about 0.08 to 2 μm. The average particle diameter of the pigment is the median diameter measured by a laser diffraction / scattering type particle size distribution measuring device. When the primary particle diameter of the pigment changes, even for the same type of pigment, the above-mentioned L * value, a * value and b * value will change. For example, when the primary particle diameter of the black pigment increases, it may become slightly bluish black. Therefore, in the present disclosure, the L * value, a * value and b *In the setting of values, it is also preferable to adjust the primary particle diameter of the pigment to be used. Note that the secondary particle diameter of the pigment is preferably about 0.8 μm or less, more preferably about 0.6 μm or less, and still more preferably about 0.4 μm or less. Also, the secondary particle diameter of the pigment is preferably about 0.05 μm or more, more preferably about 0.1 μm or more. Preferred ranges of the secondary particle diameter of the pigment include about 0.05 to 0.8 μm, about 0.05 to 0.6 μm, about 0.05 to 0.4 μm, about 0.1 to 0.8 μm, about 0.1 to 0.6 μm, and about 0.1 to 0.4 μm.

[0057] Among colorants, in order to make the appearance of the exterior material for a power storage device black, it is preferable to use a blackening agent. A blackening agent is an additive such as a pigment or a dye that can be colored black, and is a black coloring agent. Examples of the blackening agent include black pigments. Also, as the black pigment, carbon and titanium-based pigments are preferable. Note that the black pigment made of carbon is generally referred to as carbon black. As the titanium-based pigment, titanium black is preferable. Also, carbon black and titanium black may be mixed and used.

[0058] Furthermore, after making the appearance of the exterior material for a power storage device black, from the viewpoint of improving the discriminability by preferably setting the b * value to -0.20 or less, the adhesive layer 2 preferably further contains a blue agent in addition to the blackening agent. A blue agent is an additive such as a pigment or a dye that can be colored blue, and is a blue coloring agent. Examples of the blue agent include dyes such as anthraquinone and indigoid, and pigments such as phthalocyanine, ultramarine, ferric ferricyanide, and navy blue. Examples of phthalocyanine include copper phthalocyanine and metal-free phthalocyanine, and copper phthalocyanine is preferable. Copper phthalocyanine is known as a blue pigment.

[0059] When performing analysis by X-ray fluorescence spectrometry (XRF) from the outside of the laminate constituting the exterior material for the power storage device of the present disclosure, it is preferable that a Cu element is detected. For example, when a pigment containing copper (for example, copper phthalocyanine) or the like is included as the pigment of the adhesive layer 2 of the exterior material for the power storage device, when performing analysis by X-ray fluorescence spectrometry (XRF) from the outside of the laminate, a Cu element is detected. As will be described later, also when the surface coating layer 6 or the coloring layer 21 contains a pigment containing copper (for example, copper phthalocyanine) or the like, when performing analysis by X-ray fluorescence spectrometry (XRF) from the outside, a Cu element is detected. For the detection of the Cu element by X-ray fluorescence spectrometry (XRF), the measurement conditions described in the examples can be adopted.

[0060] Regarding the content of the colorant in the adhesive layer 2, when the exterior material for the power storage device is colored black and the above-mentioned b * value is -0.20 or less, there is no particular limitation. From the viewpoint of appropriately coloring, it is preferably about 0.5 mass% or more, more preferably about 1.0 mass% or more. Also, from the viewpoint of appropriately maintaining the adhesiveness between the base material layer 1 and the barrier layer 3, the content of the colorant in the adhesive layer 2 is preferably about 50.0 mass% or less, more preferably about 30.0 mass% or less, still more preferably 20.0 mass% or less. Preferred ranges of the content of the colorant in the adhesive layer 2 include about 0.5 to 50.0 mass%, about 0.5 to 30.0 mass%, about 0.5 to 20.0 mass%, about 1.0 to 50.0 mass%, about 1.0 to 30.0 mass%, and about 1.0 to 20.0 mass%.

[0061] Also, when a blackening agent is blended as the colorant in the adhesive layer 2, regarding the content of the blackening agent in the adhesive layer 2, when the exterior material for the power storage device is colored black and the above-mentioned b *If the value is -0.20 or less, there is no particular limitation. From the viewpoint of proper coloring, it is preferably about 0.5% by mass or more, more preferably about 1.0% by mass or more. Further, from the viewpoint of properly maintaining the adhesiveness between the base material layer 1 and the barrier layer 3, the content of the blackening agent in the adhesive layer 2 is preferably about 50.0% by mass or less, more preferably about 30.0% by mass or less, and still more preferably 20.0% by mass or less. Further, the preferable range of the content of the blackening agent in the adhesive layer 2 is about 0.5 to 50.0% by mass, about 0.5 to 30.0% by mass, about 0.5 to 20.0% by mass, about 1.0 to 50.0% by mass, about 1.0 to 30.0% by mass, about 1.0 to 20.0% by mass. Further, when a blue agent is blended in the adhesive layer 2, the content of the blue agent in the adhesive layer 2 is not particularly limited as long as the exterior material for the power storage device is colored black. For example, it is about 0.5 to 30% by mass, preferably 1 to 20% by mass.

[0062] Further, when a blackening agent and a blue agent are blended in the adhesive layer 2, regarding the ratio of the blackening agent and the blue agent in the adhesive layer 2, with the blackening agent as 100 parts by mass, the ratio of the blue agent is preferably about 0.1 part by mass or more, more preferably about 1 part by mass or more, and still more preferably about 10 parts by mass or more. Further, the ratio of the blue agent is preferably about 150 parts by mass or less, more preferably about 100 parts by mass or less. The preferable range of the ratio of the blue agent is about 0.1 to 150 parts by mass, about 0.1 to 100 parts by mass, about 1 to 150 parts by mass, about 1 to 100 parts by mass, about 10 to 150 parts by mass, about 10 to 100 parts by mass. As described above, by adjusting the primary particle diameter of the pigment used, the composition of the layer located outside the barrier layer 3, and further the aging treatment conditions of the exterior material for the power storage device described later, etc., the L * value, a * value and b * value can also be set. Therefore, the adhesive layer 2 may contain only a blackening agent as a coloring agent, and for example, may not contain a blue agent.

[0063] The thickness of the adhesive layer 2 is not particularly limited as long as the base material layer 1 and the barrier layer 3 can be adhered. For example, it is about 1 μm or more, about 2 μm or more. Also, the thickness of the adhesive layer 2 is, for example, about 10 μm or less, about 5 μm or less. Preferred ranges for the thickness of the adhesive layer 2 include about 1 to 10 μm, about 1 to 5 μm, about 2 to 10 μm, and about 2 to 5 μm.

[0064] [Coloring layer 21] The coloring layer 21 is a layer provided between the base material layer 1 and the barrier layer 3 as needed. When having the adhesive layer 2, the coloring layer 21 may be provided on at least one of between the base material layer 1 and the adhesive layer 2 and between the adhesive layer 2 and the barrier layer 3. Also, the coloring layer 21 may be provided on the outside of the base material layer 1. By providing the coloring layer 21, the exterior material for a power storage device can be suitably colored black.

[0065] Further, in the exterior material for a power storage device of the present disclosure, by coloring the coloring layer 21 black, after making it an exterior material for a power storage device presenting a black appearance, the b * value can be suitably set to -0.20 or less. However, similar to the case of coloring the aforementioned adhesive layer 2 black, just coloring the coloring layer 21 black does not necessarily make the b * value -0.20 or less. By adjusting the composition such as the type and content of the colorant contained in the coloring layer 21, the composition of the layer located outside the barrier layer 3 such as the base material layer 1, the surface coating layer 6 provided as needed, and the adhesive layer 2, and further the aging treatment conditions of the exterior material for a power storage device described later, the appearance of the exterior material for a power storage device can be made black and the b * value can be set to -0.20 or less. The setting of the L * value and the a * value is the same.

[0066] The coloring layer 21 can be formed, for example, by applying ink containing a colorant to the surface of the base material layer 1 or the surface of the barrier layer 3. As the colorant, known ones such as pigments and dyes can be used. Also, only one type of colorant may be used, or two or more types may be mixed and used.

[0067] Specific examples of the colorant contained in the coloring layer 21 are the same as those exemplified in the column of [adhesive layer 2].

[0068] The content of the colorant in the coloring layer 21 is not particularly limited as long as the exterior material for the power storage device is colored black and the b * value is -0.20 or less. From the viewpoint of appropriate coloring, it is preferably about 0.5% by mass or more, more preferably about 1.0% by mass or more. Also, from the viewpoint of appropriately forming the coloring layer 21, the content of the colorant in the coloring layer 21 is preferably about 50.0% by mass or less, more preferably about 30.0% by mass or less, still more preferably 20.0% by mass or less. Preferred ranges for the content of the colorant in the coloring layer 21 include about 0.5 to 50.0% by mass, about 0.5 to 30.0% by mass, about 0.5 to 20.0% by mass, about 1.0 to 50.0% by mass, about 1.0 to 30.0% by mass, and about 1.0 to 20.0% by mass.

[0069] Also, when a blackening agent is blended in the coloring layer 21, the content of the blackening agent in the coloring layer 21 is not particularly limited as long as the exterior material for the power storage device is colored black and the b * value is -0.20 or less. From the viewpoint of appropriate coloring, it is preferably about 0.5% by mass or more, more preferably about 1.0% by mass or more. Also, from the viewpoint of appropriately forming the coloring layer 21, the content of the blackening agent in the coloring layer 21 is preferably about 50.0% by mass or less, more preferably about 30.0% by mass or less, still more preferably 20.0% by mass or less. Preferred ranges for the content of the blackening agent in the coloring layer 21 include about 0.5 to 50.0% by mass, about 0.5 to 30.0% by mass, about 0.5 to 20.0% by mass, about 1.0 to 50.0% by mass, about 1.0 to 30.0% by mass, and about 1.0 to 20.0% by mass. Also, when a blue agent is blended in the coloring layer 21, the content of the blue agent in the coloring layer 21 is not particularly limited as long as the exterior material for the power storage device is colored black, and examples include about 0.5 to 30% by mass, preferably 1 to 20% by mass.

[0070] Also, when a black agent and a blue agent are blended in the coloring layer 21, regarding the ratio of the black agent and the blue agent in the coloring layer 21, with the black agent being 100 parts by mass, the ratio of the blue agent is preferably about 0.1 part by mass or more, more preferably about 1 part by mass or more, still more preferably about 10 parts by mass or more. Also, the ratio of the blue agent is preferably about 150 parts by mass or less, more preferably about 100 parts by mass or less. The preferable range of the blue agent is about 0.1 to 150 parts by mass, about 0.1 to 100 parts by mass, about 1 to 150 parts by mass, about 1 to 100 parts by mass, about 10 to 150 parts by mass, or about 10 to 100 parts by mass.

[0071] [Barrier layer 3] In the exterior material for a power storage device, the barrier layer 3 is a layer that at least suppresses the intrusion of moisture.

[0072] Examples of the barrier layer 3 include a metal foil having barrier properties, a vapor deposition film, a resin layer, etc. Examples of the vapor deposition film include a metal vapor deposition film, an inorganic oxide vapor deposition film, a carbon-containing inorganic oxide vapor deposition film, etc. Examples of the resin layer include polyvinylidene chloride, polymers mainly composed of chlorotrifluoroethylene (CTFE), polymers mainly composed of tetrafluoroethylene (TFE), polymers having a fluoroalkyl group, and fluorine-containing resins such as polymers mainly composed of fluoroalkyl units, ethylene-vinyl alcohol copolymers, etc. Also, examples of the barrier layer 3 include a resin film provided with at least one layer of these vapor deposition films and resin layers. A plurality of barrier layers 3 may be provided. The barrier layer 3 preferably includes a layer composed of a metal material. Specific examples of the metal material constituting the barrier layer 3 include aluminum alloy, stainless steel, titanium steel, steel plate, etc. When used as a metal foil, it preferably includes at least one of an aluminum alloy foil and a stainless steel foil.

[0073] The aluminum alloy foil is preferably a soft aluminum alloy foil composed of, for example, an annealed aluminum alloy or the like from the viewpoint of improving the formability of the exterior material for the power storage device. From the viewpoint of further improving the formability, it is preferably an aluminum alloy foil containing iron. In the aluminum alloy foil containing iron (100% by mass), the iron content is preferably 0.1 to 9.0% by mass, and more preferably 0.5 to 2.0% by mass. When the iron content is 0.1% by mass or more, an exterior material for the power storage device having better formability can be obtained. When the iron content is 9.0% by mass or less, an exterior material for the power storage device having better flexibility can be obtained. Examples of the soft aluminum alloy foil include aluminum alloy foils having compositions defined in JIS H4160:1994 A8021H-O, JIS H4160:1994 A8079H-O, JIS H4000:2014 A8021P-O, or JIS H4000:2014 A8079P-O. Also, silicon, magnesium, copper, manganese, etc. may be added as necessary. The softening can be performed by annealing or the like.

[0074] Examples of the stainless steel foil include austenitic, ferritic, austenitic-ferritic, martensitic, and precipitation-hardening stainless steel foils. From the viewpoint of providing an exterior material for the power storage device with excellent formability, the stainless steel foil is preferably composed of austenitic stainless steel.

[0075] Specific examples of the austenitic stainless steel constituting the stainless steel foil include SUS304, SUS301, SUS316L, etc. Among these, SUS304 is particularly preferred.

[0076] In the case of a metal foil, the thickness of the barrier layer 3 only needs to exhibit a function as a barrier layer that at least suppresses the intrusion of moisture, and for example, it can be about 9 to 200 μm. The thickness of the barrier layer 3 is preferably about 85 μm or less, more preferably about 50 μm or less, still more preferably about 40 μm or less, and particularly preferably about 35 μm or less. Also, the thickness of the barrier layer 3 is preferably about 10 μm or more, still more preferably about 20 μm or more, and more preferably about 25 μm or more. Preferred ranges of the thickness include about 10 to 85 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 35 μm, about 20 to 85 μm, about 20 to 50 μm, about 20 to 40 μm, about 20 to 35 μm, about 25 to 85 μm, about 25 to 50 μm, about 25 to 40 μm, and about 25 to 35 μm. When the barrier layer 3 is composed of an aluminum alloy foil, the above-described range is particularly preferred. Also, particularly when the barrier layer 3 is composed of a stainless steel foil, the thickness of the stainless steel foil is preferably about 60 μm or less, more preferably about 50 μm or less, still more preferably about 40 μm or less, still more preferably about 30 μm or less, and particularly preferably about 25 μm or less. Also, the thickness of the stainless steel foil is preferably about 10 μm or more, and more preferably about 15 μm or more. Also, preferred ranges of the thickness of the stainless steel foil include about 10 to 60 μm, about 10 to 50 μm, about 10 to 40 μm, about 10 to 30 μm, about 10 to 25 μm, about 15 to 60 μm, about 15 to 50 μm, about 15 to 40 μm, about 15 to 30 μm, and about 15 to 25 μm.

[0077] Also, when the barrier layer 3 is a metal foil, it is preferable to provide a corrosion-resistant film on at least the surface opposite to the base material layer in order to prevent dissolution and corrosion. The barrier layer 3 may be provided with corrosion-resistant films on both sidesHere, the corrosion-resistant film refers to, for example, a thin film that is formed by performing a hot water conversion treatment such as a boehmite treatment, a chemical conversion treatment, an anodizing treatment, a plating treatment such as nickel or chromium, or a corrosion prevention treatment of applying a coating agent on the surface of the barrier layer to impart corrosion resistance to the barrier layer. As the treatment for forming the corrosion-resistant film, one type may be performed, or two or more types may be combined. Further, not only a single layer but also a multilayer structure can be formed. Furthermore, among these treatments, the hot water conversion treatment and the anodizing treatment are treatments that dissolve the surface of the metal foil with a treatment agent and form a metal compound having excellent corrosion resistance. Note that these treatments may be included in the definition of the chemical conversion treatment. Also, when the barrier layer 3 is provided with a corrosion-resistant film, the barrier layer 3 includes the corrosion-resistant film.

[0078] The corrosion-resistant film prevents delamination between the barrier layer (for example, an aluminum alloy foil) and the base material layer during the molding of the exterior material for the power storage device, and prevents dissolution and corrosion of the surface of the barrier layer due to hydrogen fluoride generated by the reaction of the electrolyte and moisture. In particular, when the barrier layer is an aluminum alloy foil, it prevents dissolution and corrosion of aluminum oxide present on the surface of the barrier layer, and improves the adhesiveness (wettability) of the surface of the barrier layer, showing the effect of preventing delamination between the base material layer and the barrier layer during heat sealing and preventing delamination between the base material layer and the barrier layer during molding.

[0079] As the corrosion-resistant film formed by chemical conversion treatment, various types are known, and mainly include corrosion-resistant films containing at least one of phosphates, chromates, fluorides, triazine thiol compounds, and rare earth oxides. Examples of chemical conversion treatments using phosphates and chromates include chromic acid chromate treatment, phosphoric acid chromate treatment, phosphate-chromate treatment, chromate treatment, etc. Examples of chromium compounds used in these treatments include chromium nitrate, chromium fluoride, chromium sulfate, chromium acetate, chromium oxalate, chromium metaphosphate, acetylacetate chromium, chromium chloride, potassium chromium sulfate, etc. Examples of phosphorus compounds used in these treatments include sodium phosphate, potassium phosphate, ammonium phosphate, polyphosphoric acid, etc. Examples of chromate treatments include etching chromate treatment, electrolytic chromate treatment, coating-type chromate treatment, etc., and coating-type chromate treatment is preferred. This coating-type chromate treatment first degreases at least the inner layer side surface of the barrier layer (e.g., aluminum alloy foil) by well-known treatment methods such as alkaline immersion method, electrolytic cleaning method, acid cleaning method, electrolytic acid cleaning method, acid activation method, etc. Then, a treatment liquid mainly composed of metal phosphates such as chromium (Cr) phosphate, titanium (Ti) phosphate, zirconium (Zr) phosphate, zinc (Zn) phosphate, etc. and mixtures of these metal salts, or a treatment liquid mainly composed of non-metal phosphates and mixtures of these non-metal salts, or a treatment liquid composed of a mixture of these and synthetic resin, etc. is applied by well-known coating methods such as roll coating method, gravure printing method, immersion method, etc. and dried. For the treatment liquid, various solvents such as water, alcohol-based solvents, hydrocarbon-based solvents, ketone-based solvents, ester-based solvents, ether-based solvents, etc. can be used, and water is preferred. Examples of the resin component used at this time include polymers such as phenolic resins and acrylic resins, and chromate treatment using an aminated phenol polymer having repeating units represented by the following general formulas (1) to (4) can be mentioned. In the aminated phenol polymer, the repeating units represented by the following general formulas (1) to (4) may be contained alone or in any combination of two or more types.The acrylic resin is preferably a derivative such as polyacrylic acid, an acrylic acid-methacrylic acid ester copolymer, an acrylic acid-maleic acid copolymer, an acrylic acid-styrene copolymer, or their sodium salts, ammonium salts, amine salts, etc. In particular, derivatives of polyacrylic acid such as ammonium salts, sodium salts, or amine salts of polyacrylic acid are preferred. In the present disclosure, polyacrylic acid means a polymer of acrylic acid. Further, the acrylic resin is also preferably a copolymer of acrylic acid and a dicarboxylic acid or a dicarboxylic anhydride, and is also preferably an ammonium salt, a sodium salt, or an amine salt of a copolymer of acrylic acid and a dicarboxylic acid or a dicarboxylic anhydride. Only one type of acrylic resin may be used, or two or more types may be mixed and used.

[0080]

Chem.

[0081]

Chem.

[0082]

Chem.

[0083]

Chem.

[0084] In general formulas (1) to (4), X represents a hydrogen atom, a hydroxy group, an alkyl group, a hydroxyalkyl group, an allyl group or a benzyl group. Also, R 1 and R 2 each independently represent the same or different hydroxy groups, alkyl groups, or hydroxyalkyl groups. In general formulas (1) to (4), X, R 1 and R 2Examples of the alkyl group represented by [alkyl group] include linear or branched alkyl groups having 1 to 4 carbon atoms such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, and tert-butyl group. Further, X, R 1 and R 2 Examples of the hydroxyalkyl group represented by [hydroxyalkyl group] include linear or branched alkyl groups having 1 to 4 carbon atoms substituted with one hydroxy group such as hydroxymethyl group, 1-hydroxyethyl group, 2-hydroxyethyl group, 1-hydroxypropyl group, 2-hydroxypropyl group, 3-hydroxypropyl group, 1-hydroxybutyl group, 2-hydroxybutyl group, 3-hydroxybutyl group, and 4-hydroxybutyl group. In General Formulas (1) to (4), the alkyl groups and hydroxyalkyl groups represented by X, R 1 and R 2 may be the same or different from each other. In General Formulas (1) to (4), X is preferably a hydrogen atom, a hydroxy group, or a hydroxyalkyl group. The number average molecular weight of the aminated phenol polymer having repeating units represented by General Formulas (1) to (4) is preferably about 500 to 1,000,000, and more preferably about 1,000 to 20,000. The aminated phenol polymer is produced, for example, by polycondensing a phenol compound or a naphthol compound and formaldehyde to produce a polymer composed of the repeating units represented by the above General Formula (1) or General Formula (3), and then introducing a functional group (-CH2NR 1 R 2 ) into the polymer obtained above using formaldehyde and an amine (R 1 R 2 NH). The aminated phenol polymer is used alone or in a mixture of two or more.

[0085] As another example of the corrosion-resistant film, there is a thin film formed by a coating-type corrosion prevention treatment in which a coating agent containing at least one selected from the group consisting of rare earth element oxide sols, anionic polymers, and cationic polymers is applied. The coating agent may further contain phosphoric acid or a phosphate, and a crosslinking agent for crosslinking the polymer. In the rare earth element oxide sol, fine particles of a rare earth element oxide (for example, particles having an average particle size of 100 nm or less) are dispersed in a liquid dispersion medium. Examples of the rare earth element oxide include cerium oxide, yttrium oxide, neodymium oxide, lanthanum oxide, etc., and cerium oxide is preferable from the viewpoint of further improving the adhesion. The rare earth element oxide contained in the corrosion-resistant film can be used alone or in combination of two or more. As the liquid dispersion medium of the rare earth element oxide sol, various solvents such as water, alcohol solvents, hydrocarbon solvents, ketone solvents, ester solvents, and ether solvents can be used, and water is preferable. Examples of the cationic polymer include polyethyleneimine, an ion polymer complex composed of polyethyleneimine and a polymer having a carboxylic acid, a primary amine graft acrylic resin obtained by graft polymerizing a primary amine onto an acrylic main skeleton, polyallylamine or its derivative, and aminated phenol. Further, as the anionic polymer, poly(meth)acrylic acid or its salt, or a copolymer mainly composed of (meth)acrylic acid or its salt is preferable. Further, it is preferable that the crosslinking agent is at least one selected from the group consisting of a compound having any functional group of an isocyanate group, a glycidyl group, a carboxyl group, and an oxazoline group and a silane coupling agent. Further, it is preferable that the phosphoric acid or the phosphate is a condensed phosphoric acid or a condensed phosphate.

[0086] As an example of the corrosion-resistant film, there is one formed by applying, to the surface of a barrier layer, a dispersion of fine particles of metal oxides such as aluminum oxide, titanium oxide, cerium oxide, and tin oxide and barium sulfate in phosphoric acid, and performing a baking treatment at 150 °C or higher.

[0087] The corrosion-resistant film may, if necessary, have a laminated structure in which at least one of a cationic polymer and an anionic polymer is further laminated. Examples of the cationic polymer and the anionic polymer include those described above.

[0088] Note that the analysis of the composition of the corrosion-resistant film can be performed, for example, using time-of-flight secondary ion mass spectrometry.

[0089] The amount of the corrosion-resistant film formed on the surface of the barrier layer 3 in the chemical conversion treatment is not particularly limited. For example, in the case of performing a coating-type chromate treatment, per 1 m² of the surface of the barrier layer 3, 2 the chromium compound is preferably contained in an amount of about 0.5 to 50 mg, more preferably about 1.0 to 40 mg, in terms of chromium conversion, the phosphorus compound is preferably contained in an amount of about 0.5 to 50 mg, more preferably about 1.0 to 40 mg, in terms of phosphorus conversion, and the aminated phenol polymer is preferably contained in an amount of about 1.0 to 200 mg, more preferably about 5.0 to 150 mg.

[0090] The thickness of the corrosion-resistant film is not particularly limited. However, from the viewpoints of the cohesion of the film and the adhesion to the barrier layer or the heat-sealable resin layer, it is preferably about 1 nm to 20 μm, more preferably about 1 nm to 100 nm, and even more preferably about 1 nm to 5 nm. The thickness of the corrosion-resistant film can be measured by observation with a transmission electron microscope, or in combination with observation with a transmission electron microscope and energy-dispersive X-ray spectroscopy or electron energy loss spectroscopy. By analyzing the composition of the corrosion-resistant film using time-of-flight secondary ion mass spectrometry, for example, peaks derived from secondary ions composed of at least one of Ce, P, and O (e.g., at least one of Ce₂PO₄, CePO₄, etc.) and secondary ions composed of, for example, Cr, P, and O (e.g., at least one of CrPO₂, CrPO₄, etc.) are detected. + 、CePO4 - For example, secondary ions composed of at least one of Cr, P, and O (e.g., at least one of CrPO₂, CrPO₄, etc.) + 、CrPO4 - etc.) are detected.

[0091] The chemical conversion treatment is performed by applying a solution containing a compound used for forming a corrosion-resistant film onto the surface of the barrier layer by means of a bar coating method, a roll coating method, a gravure coating method, a dipping method, etc., and then heating the barrier layer so that its temperature reaches about 70 to 200°C. Also, before subjecting the barrier layer to the chemical conversion treatment, the barrier layer may be preliminarily subjected to a degreasing treatment by means of an alkali dipping method, an electrolytic cleaning method, an acid cleaning method, an electrolytic acid cleaning method, etc. By performing the degreasing treatment in this way, it becomes possible to perform the chemical conversion treatment on the surface of the barrier layer more efficiently. Further, by using an acid degreasing agent in which a fluorine-containing compound is dissolved in an inorganic acid for the degreasing treatment, it is possible to form not only a degreasing effect on the metal foil but also a fluoride of a passive metal. In such a case, only the degreasing treatment may be performed.

[0092] [Heat-sealable resin layer 4] In the exterior material for a power storage device of the present disclosure, the heat-sealable resin layer 4 corresponds to the innermost layer and is a layer (sealing layer) that exhibits a function of heat-sealing the heat-sealable resin layers to seal the power storage device element during the assembly of the power storage device.

[0093] The resin constituting the heat-sealable resin layer 4 is not particularly limited as long as it is heat-sealable, but resins containing a polyolefin backbone such as polyolefin and acid-modified polyolefin are preferred. Whether the resin constituting the heat-sealable resin layer 4 contains a polyolefin backbone can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, etc. Also, when the resin constituting the heat-sealable resin layer 4 is analyzed by infrared spectroscopy, it is preferable that a peak derived from maleic anhydride is detected. For example, when measuring maleic anhydride-modified polyolefin by infrared spectroscopy, peaks derived from maleic anhydride are detected in the vicinity of a wave number of 1760 cm -1 and in the vicinity of a wave number of 1780 cm -1 When the heat-sealable resin layer 4 is a layer composed of maleic anhydride-modified polyolefin, peaks derived from maleic anhydride are detected when measured by infrared spectroscopy. However, if the degree of acid modification is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

[0094] Examples of polyolefins specifically include polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene; ethylene-α-olefin copolymers; polypropylene such as homopolypropylene, block copolymers of polypropylene (e.g., block copolymers of propylene and ethylene), random copolymers of polypropylene (e.g., random copolymers of propylene and ethylene), etc.; propylene-α-olefin copolymers; and terpolymers of ethylene-butene-propylene. Among these, polypropylene is preferred. The polyolefin resin in the case of being a copolymer may be a block copolymer or a random copolymer. These polyolefin-based resins may be used alone or in combination of two or more.

[0095] Also, the polyolefin may be a cyclic polyolefin. The cyclic polyolefin is a copolymer of an olefin and a cyclic monomer. Examples of the olefin that is a constituent monomer of the cyclic polyolefin include ethylene, propylene, 4-methyl-1-pentene, styrene, butadiene, isoprene, etc. Examples of the cyclic monomer that is a constituent monomer of the cyclic polyolefin include cyclic alkenes such as norbornene; and cyclic dienes such as cyclopentadiene, dicyclopentadiene, cyclohexadiene, norbornadiene. Among these, cyclic alkenes are preferred, and norbornene is more preferred.

[0096] The acid-modified polyolefin is a polymer obtained by modifying a polyolefin by block polymerization or graft polymerization with an acid component. As the polyolefin to be acid-modified, the above-mentioned polyolefins, copolymers obtained by copolymerizing the above-mentioned polyolefins with polar molecules such as acrylic acid or methacrylic acid, or polymers such as crosslinked polyolefins can also be used. Examples of the acid component used for acid modification include carboxylic acids such as maleic acid, acrylic acid, itaconic acid, crotonic acid, maleic anhydride, and itaconic anhydride or their anhydrides.

[0097] The acid-modified polyolefin may be an acid-modified cyclic polyolefin. The acid-modified cyclic polyolefin is a polymer obtained by copolymerizing a part of the monomers constituting the cyclic polyolefin by replacing it with an acid component, or by block-polymerizing or graft-polymerizing an acid component onto the cyclic polyolefin. The cyclic polyolefin to be acid-modified is the same as described above. Also, the acid component used for acid modification is the same as the acid component used for modifying the above polyolefin.

[0098] Preferred acid-modified polyolefins include polyolefins modified with carboxylic acid or its anhydride, polypropylenes modified with carboxylic acid or its anhydride, maleic anhydride-modified polyolefins, and maleic anhydride-modified polypropylenes.

[0099] The heat-sealable resin layer 4 may be formed of a single resin alone, or may be formed of a blend polymer combining two or more resins. Further, the heat-sealable resin layer 4 may be formed of only one layer, but may also be formed of two or more layers with the same or different resins.

[0100] Also, the heat-sealable resin layer 4 may contain a lubricant or the like as necessary. When the heat-sealable resin layer 4 contains a lubricant, the moldability of the exterior material for the power storage device can be enhanced. The lubricant is not particularly limited, and known lubricants can be used. The lubricant may be used alone or in combination of two or more.

[0101] The lubricant is not particularly limited, but preferably includes amide-based lubricants. Specific examples of the lubricant include those exemplified in the base material layer 1. The lubricant may be used alone or in combination of two or more.

[0102] When a lubricant is present on the surface of the heat-sealable resin layer 4, the amount thereof is not particularly limited, but from the viewpoint of enhancing the moldability of the exterior material for the power storage device, it is preferably about 10 to 50 mg / m 2 level, more preferably about 15 to 40 mg / m 2 level.

[0103] The lubricant present on the surface of the heat-sealable resin layer 4 may be one obtained by exuding the lubricant contained in the resin constituting the heat-sealable resin layer 4, or may be one obtained by applying a lubricant to the surface of the heat-sealable resin layer 4.

[0104] Also, the thickness of the heat-sealable resin layer 4 is not particularly limited as long as the heat-sealable resin layers can exhibit the function of heat-sealing to seal the power storage device element. For example, it is about 100 μm or less, preferably about 85 μm or less, and more preferably about 15 to 85 μm. For example, when the thickness of the adhesive layer 5 described later is 10 μm or more, the thickness of the heat-sealable resin layer 4 is preferably about 85 μm or less, and more preferably about 15 to 45 μm. For example, when the thickness of the adhesive layer 5 described later is less than 10 μm or when the adhesive layer 5 is not provided, the thickness of the heat-sealable resin layer 4 is preferably about 20 μm or more, and more preferably about 35 to 85 μm.

[0105] [Adhesive layer 5] In the exterior material for the power storage device of the present disclosure, the adhesive layer 5 is a layer provided between the barrier layer 3 (or a corrosion-resistant film (such as an acid-resistant film)) and the heat-sealable resin layer 4 as necessary to firmly bond them.

[0106] The subsequent layer 5 is formed of a resin that can adhere the barrier layer 3 and the heat-sealable resin layer 4. As the resin used for forming the adhesive layer 5, for example, the same adhesives as those exemplified for the adhesive layer 2 can be used. In addition, it is preferable that the resin used for forming the adhesive layer 5 contains a polyolefin backbone, and examples thereof include the polyolefins and acid-modified polyolefins exemplified for the aforementioned heat-sealable resin layer 4. Whether the resin constituting the adhesive layer 5 contains a polyolefin backbone can be analyzed by, for example, infrared spectroscopy, gas chromatography-mass spectrometry, etc., and the analysis method is not particularly limited. Further, when the resin constituting the adhesive layer 5 is analyzed by infrared spectroscopy, it is preferable that a peak derived from maleic anhydride is detected. For example, when measuring maleic anhydride-modified polyolefin by infrared spectroscopy, peaks derived from maleic anhydride are detected in the vicinity of a wave number of 1760 cm -1 -1 and in the vicinity of a wave number of 1780 cm -1 -1. However, if the degree of acid modification is low, the peak may become small and may not be detected. In that case, it can be analyzed by nuclear magnetic resonance spectroscopy.

[0107] From the viewpoint of firmly adhering the barrier layer 3 and the heat-sealable resin layer 4, the adhesive layer 5 preferably contains an acid-modified polyolefin. As the acid-modified polyolefin, polyolefin modified with a carboxylic acid or its anhydride, polypropylene modified with a carboxylic acid or its anhydride, maleic anhydride-modified polyolefin, and maleic anhydride-modified polypropylene are particularly preferable.

[0108] Furthermore, from the viewpoint of making the exterior material for a power storage device have excellent shape stability after molding while reducing the thickness of the exterior material for a power storage device, the adhesive layer 5 is more preferably a cured product of a resin composition containing an acid-modified polyolefin and a curing agent. As the acid-modified polyolefin, preferably, those described above can be exemplified.

[0109] Further, the adhesive layer 5 is preferably a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and a compound having an epoxy group, and particularly preferably a cured product of a resin composition containing an acid-modified polyolefin and at least one selected from the group consisting of a compound having an isocyanate group and a compound having an epoxy group. Further, the adhesive layer 5 preferably contains at least one selected from the group consisting of polyurethane, polyester, and epoxy resin, and more preferably contains polyurethane and epoxy resin. As the polyester, for example, an amide ester resin is preferable. The amide ester resin is generally produced by the reaction of a carboxyl group and an oxazoline group. The adhesive layer 5 is more preferably a cured product of a resin composition containing at least one of these resins and the acid-modified polyolefin. When unreacted products of curing agents such as a compound having an isocyanate group, a compound having an oxazoline group, and an epoxy resin remain in the adhesive layer 5, the presence of the unreacted products can be confirmed by a method selected from, for example, infrared spectroscopy, Raman spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), etc.

[0110] Further, from the viewpoint of further enhancing the adhesion between the barrier layer 3 and the adhesive layer 5, the adhesive layer 5 is preferably a cured product of a resin composition containing a curing agent having at least one selected from the group consisting of an oxygen atom, a heterocyclic ring, a C=N bond, and a C-O-C bond. Examples of the curing agent having a heterocyclic ring include a curing agent having an oxazoline group and a curing agent having an epoxy group. Examples of the curing agent having a C=N bond include a curing agent having an oxazoline group and a curing agent having an isocyanate group. Examples of the curing agent having a C-O-C bond include a curing agent having an oxazoline group, a curing agent having an epoxy group, and polyurethane. The fact that the adhesive layer 5 is a cured product of a resin composition containing these curing agents can be confirmed by methods such as gas chromatography-mass spectrometry (GCMS), infrared spectroscopy (IR), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and X-ray photoelectron spectroscopy (XPS).

[0111] The compound having an isocyanate group is not particularly limited, but from the viewpoint of effectively enhancing the adhesion between the barrier layer 3 and the adhesive layer 5, a polyfunctional isocyanate compound is preferably used. The polyfunctional isocyanate compound is not particularly limited as long as it is a compound having two or more isocyanate groups. Specific examples of the polyfunctional isocyanate-based curing agent include pentane diisocyanate (PDI), isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), those obtained by polymerizing or nurating these, mixtures thereof, and copolymers with other polymers. Further, adducts, burettes, isocyanurates, etc. are included.

[0112] The content of the compound having an isocyanate group in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, and more preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. Thereby, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively enhanced.

[0113] The compound having an oxazoline group is not particularly limited as long as it is a compound having an oxazoline skeleton. Specific examples of the compound having an oxazoline group include those having a polystyrene main chain and those having an acrylic main chain. Further, as commercially available products, for example, the Epocros series manufactured by Nippon Shokubai Co., Ltd. etc. are included.

[0114] The ratio of the compound having an oxazoline group in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, and more preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. Thereby, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively enhanced.

[0115] Examples of the compound having an epoxy group include, for example, epoxy resins. The epoxy resin is not particularly limited as long as it is a resin capable of forming a crosslinked structure by the epoxy groups present in the molecule, and known epoxy resins can be used. The weight average molecular weight of the epoxy resin is preferably about 50 to 2000, more preferably about 100 to 1000, and even more preferably about 200 to 800. In the present disclosure, the weight average molecular weight of the epoxy resin is a value measured by gel permeation chromatography (GPC) measured under the conditions using polystyrene as a standard sample.

[0116] Specific examples of the epoxy resin include glycidyl ether derivatives of trimethylolpropane, bisphenol A diglycidyl ether, modified bisphenol A diglycidyl ether, novolak glycidyl ether, glycerin polyglycidyl ether, polyglycerin polyglycidyl ether, and the like. The epoxy resin may be used alone or in combination of two or more.

[0117] The proportion of the epoxy resin in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, more preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. Thereby, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively enhanced.

[0118] The polyurethane is not particularly limited, and known polyurethanes can be used. The adhesive layer 5 may be, for example, a cured product of a two-component curable polyurethane.

[0119] The proportion of the polyurethane in the adhesive layer 5 is preferably in the range of 0.1 to 50% by mass, more preferably in the range of 0.5 to 40% by mass in the resin composition constituting the adhesive layer 5. Thereby, the adhesion between the barrier layer 3 and the adhesive layer 5 can be effectively enhanced in an atmosphere where components that induce corrosion of the barrier layer such as an electrolytic solution are present.

[0120] In addition, when the adhesive layer 5 is a cured product of a resin composition containing at least one selected from the group consisting of a compound having an isocyanate group, a compound having an oxazoline group, and an epoxy resin, and the acid-modified polyolefin, the acid-modified polyolefin functions as a main agent, and the compound having an isocyanate group, the compound having an oxazoline group, and the compound having an epoxy group each function as a curing agent.

[0121] The thickness of the adhesive layer 5 is preferably about 50 μm or less, about 40 μm or less, about 30 μm or less, about 20 μm or less, about 5 μm or less. Also, the thickness of the adhesive layer 5 is preferably about 0.1 μm or more, about 0.5 μm or more. As the range of the thickness, preferably, it is about 0.1 to 50 μm, about 0.1 to 40 μm, about 0.1 to 30 μm, about 0.1 to 20 μm, about 0.1 to 5 μm, about 0.5 to 50 μm, about 0.5 to 40 μm, about 0.5 to 30 μm, about 0.5 to 20 μm, about 0.5 to 5 μm. More specifically, in the case of the adhesive exemplified in the adhesive layer 2 or a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, preferably, it is about 1 to 10 μm, more preferably about 1 to 5 μm. Also, in the case of using the resin exemplified in the heat-fusible resin layer 4, preferably, it is about 2 to 50 μm, more preferably about 10 to 40 μm. When the adhesive layer 5 is the adhesive exemplified in the adhesive layer 2 or a cured product of a resin composition containing an acid-modified polyolefin and a curing agent, for example, the adhesive layer 5 can be formed by applying the resin composition and curing it by heating or the like. Also, in the case of using the resin exemplified in the heat-fusible resin layer 4, for example, it can be formed by extrusion molding of the heat-fusible resin layer 4 and the adhesive layer 5.

[0122] [Surface coating layer 6] The exterior material for a power storage device of the present disclosure may be provided with a surface coating layer 6 on the upper side of the base material layer 1 (on the side opposite to the barrier layer 3 of the base material layer 1), if necessary, for the purpose of improving at least one of design, electrolyte resistance, scratch resistance, moldability, etc. The surface coating layer 6 is a layer located on the outermost layer side of the exterior material for a power storage device when the power storage device is assembled using the exterior material for a power storage device. As described above, in the exterior material for a power storage device of the present disclosure, when the b * value is -0.20 or less, an excellent effect of the discriminability of the identification label printed on the surface is exhibited under the light source in the yellow room. However, although the exterior material for a power storage device may slightly exhibit blue and color unevenness may be visually recognized, when the surface coating layer 6 is provided on the outermost layer of the exterior material for a power storage device of the present disclosure, since the surface coating layer has an effect of diffusing light and suppressing gloss, the occurrence of color unevenness is suppressed and there is an advantage that the appearance uniformity is enhanced. On the other hand, when the outermost layer of the exterior material for a power storage device of the present disclosure does not have the surface coating layer 6, the gloss of the surface of the exterior material for a power storage device is high and scratches are easily noticeable, but when the surface coating layer 6 is provided, since the surface coating layer has an effect of diffusing light and suppressing gloss, there is also an advantage that scratches are not easily noticeable. These advantages are particularly likely to be exhibited when the surface coating layer 6 contains an additive (especially a matting agent) described later.

[0123] Further, in the exterior material for a power storage device of the present disclosure, by coloring the surface coating layer 6 black, after making the exterior material for a power storage device have a black appearance, the b * value can be preferably set to -0.20 or less. However, similar to the case of coloring the adhesive layer 2 and the coloring layer 21 black described above, simply coloring the surface coating layer 6 black does not necessarily make the b * value -0.20 or less. By adjusting the composition such as the type and content of the colorant contained in the surface coating layer 6, the composition of the layer located outside the barrier layer 3 such as the base material layer 1, the adhesive layer 2 and the coloring layer 21 provided if necessary, and further, the aging treatment conditions of the exterior material for a power storage device described later, the appearance of the exterior material for a power storage device can be made black and the b * value can be set to -0.20 or less. L* Value and a * The same applies to the setting of the value.

[0124] The surface coating layer 6 can be formed of a resin such as polyvinylidene chloride, polyester, polyurethane, acrylic resin, epoxy resin, or the like.

[0125] When the resin forming the surface coating layer 6 is a curable resin, the resin may be either a one-component curable type or a two-component curable type, but preferably a two-component curable type. Examples of the two-component curable resin include two-component curable polyurethane, two-component curable polyester, two-component curable epoxy resin, and the like. Among these, two-component curable polyurethane is preferable.

[0126] Examples of the two-component curable polyurethane include polyurethanes containing a main agent containing a polyol compound and a curing agent containing an isocyanate compound. Preferably, a two-component curable polyurethane using a polyol such as a polyester polyol, a polyether polyol, or an acrylic polyol as the main agent and an aromatic or aliphatic polyisocyanate as the curing agent can be mentioned. Further, as the polyol compound, it is preferable to use a polyester polyol having a hydroxyl group not only at the terminal of the repeating unit but also in the side chain. Examples of the curing agent include aliphatic, alicyclic, aromatic, and araliphatic isocyanate compounds. Examples of the isocyanate compound include hexamethylene diisocyanate (HDI), xylylene diisocyanate (XDI), isophorone diisocyanate (IPDI), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthalene diisocyanate (NDI), and the like. Further, examples include polyfunctional isocyanate modified products derived from one or more of these diisocyanates. Further, a multimer (for example, a trimer) can also be used as the polyisocyanate compound. Examples of such multimers include adducts, biurets, and nurates. The formation of the surface coating layer 6 from polyurethane imparts excellent electrolyte resistance to the exterior material for the power storage device.

[0127] The surface coating layer 6 may contain additives such as the lubricants, colorants, antiblocking agents, matting agents, flame retardants, antioxidants, tackifiers, and antistatic agents described above, as necessary, depending on the functionality to be provided on at least one of the surface and the interior of the surface coating layer 6 and its surface. Examples of the additives include fine particles having an average particle diameter of about 0.5 nm to 5 μm. The average particle diameter of the additives is the median diameter measured by a laser diffraction / scattering type particle size distribution measuring device.

[0128] The additive may be either an inorganic substance or an organic substance. Also, the shape of the additive is not particularly limited, and examples thereof include spherical, fibrous, plate-like, amorphous, scaly, and the like.

[0129] Specific examples of the additive include talc, silica, graphite, kaolin, montmorillonite, mica, hydrotalcite, silica gel, zeolite, aluminum hydroxide, magnesium hydroxide, zinc oxide, magnesium oxide, aluminum oxide, neodymium oxide, antimony oxide, titanium oxide, cerium oxide, calcium sulfate, barium sulfate, calcium carbonate, calcium silicate, lithium carbonate, calcium benzoate, calcium oxalate, magnesium stearate, alumina, carbon black, carbon nanotube, high melting point nylon, acrylate resin, crosslinked acrylic, crosslinked styrene, crosslinked polyethylene, benzoguanamine, gold, aluminum, copper, nickel, and the like. The additive may be used alone or in combination of two or more. Among these additives, from the viewpoint of improving the discriminability, it is preferable to use calcium carbonate. Since calcium carbonate has a bluish tint, by using it as an additive for the surface coating layer, the b * value can be suitably set to -0.20 or less. Also, it is preferable to use a mixture of silica and calcium carbonate as the additive. By using silica as an additive for the surface coating layer, it becomes easier to diffuse the reflected light, and it is possible to make the appearance of the exterior material for the power storage device more bluish, and the b * value can be suitably set to -0.20 or less. Also, among these additives, from the viewpoints of dispersion stability and cost, silica, barium sulfate, and titanium oxide are preferably mentioned. Also, various surface treatments such as insulation treatment and high dispersibility treatment may be performed on the surface of the additive.

[0130] When the surface coating layer 6 contains a colorant, known colorants such as pigments and dyes can be used as the colorant. Also, only one type of colorant may be used, or two or more types may be mixed and used. Specific examples of the colorant contained in the surface coating layer 6 are the same as those exemplified in the column of [adhesive layer 2]. Also, the preferable content of the colorant contained in the surface coating layer 6 is the same as the content described in the column of [adhesive layer 2].

[0131] For example, when a blackening agent is blended in the surface coating layer 6, the content of the blackening agent in the surface coating layer 6 is not particularly limited as long as the exterior material for the power storage device is colored black. For example, it is about 5 to 60% by mass, preferably about 10 to 40% by mass. Also, when a blue agent is blended in the surface coating layer 6, the content of the blue agent in the surface coating layer 6 is not particularly limited as long as the exterior material for the power storage device is colored black. For example, it is about 0.5 to 30% by mass, preferably about 1 to 20% by mass.

[0132] Also, for example, when a blackening agent and a blue agent are blended in the surface coating layer 6, regarding the ratio of the blackening agent and the blue agent in the surface coating layer 6, with the blackening agent being 100 parts by mass, the ratio of the blue agent is preferably about 0.1 part by mass or more, more preferably about 1 part by mass or more, and even more preferably about 10 parts by mass or more. Also, the ratio of the blue agent is preferably about 150 parts by mass or less, more preferably about 100 parts by mass or less. Also, the preferable range of the blue agent is about 0.1 to 150 parts by mass, about 0.1 to 100 parts by mass, about 1 to 150 parts by mass, about 1 to 100 parts by mass, about 10 to 150 parts by mass, about 10 to 100 parts by mass.

[0133] The method for forming the surface coating layer 6 is not particularly limited. For example, a method of applying a resin for forming the surface coating layer 6 can be mentioned. When an additive is blended in the surface coating layer 6, a resin mixed with the additive may be applied.

[0134] The thickness of the surface coating layer 6 is not particularly limited as long as the above functions of the surface coating layer 6 are exhibited. For example, it is about 0.5 to 10 μm, preferably about 1 to 5 μm.

[0135] For example, when the adhesive layer is a layer colored black, the surface coating layer located outside the adhesive layer is preferably transparent or translucent.

[0136] 3. Manufacturing Method of Exterior Material for Energy Storage Device The manufacturing method of the exterior material for a power storage device is not particularly limited as long as a laminate in which each layer included in the exterior material for a power storage device of the present disclosure is laminated can be obtained, and examples thereof include a method including a step of laminating at least a base material layer 1, a barrier layer 3, and a heat-sealable resin layer 4 in this order. Specifically, the manufacturing method of the exterior material for a power storage device of the present disclosure is a manufacturing method of an exterior material for a power storage device having a black appearance, and includes a step of obtaining a laminate in which at least a base material layer, a barrier layer, and a heat-sealable resin layer are laminated in order from the outside. Under the measurement conditions of the SCI method, a viewing angle of 10°, and a light source F2, the L of the reflected light measured from the outside of the laminate * a * b * b value in the color space * is -0.20 or less.

[0137] As an example of the manufacturing method of the exterior material for a power storage device of the present disclosure, it is as follows. First, a laminate (hereinafter, sometimes referred to as "laminate A") in which a base material layer 1, an adhesive layer 2, and a barrier layer 3 are laminated in this order is formed. The formation of laminate A can be specifically performed by applying an adhesive used for forming the adhesive layer 2 on the base material layer 1 or on the barrier layer 3 whose surface has been chemically converted as necessary, drying it by a coating method such as a gravure coating method or a roll coating method, and then laminating the barrier layer 3 or the base material layer 1 and curing the adhesive layer 2 by a dry lamination method.

[0138] Next, a heat-sealable resin layer 4 is laminated on the barrier layer 3 of the laminate A. When directly laminating the heat-sealable resin layer 4 on the barrier layer 3, it may be laminated on the barrier layer 3 of the laminate A by methods such as the thermal lamination method or the extrusion lamination method. Further, when an adhesive layer 5 is provided between the barrier layer 3 and the heat-sealable resin layer 4, for example, (1) a method of laminating by extruding the adhesive layer 5 and the heat-sealable resin layer 4 on the barrier layer 3 of the laminate A (co-extrusion lamination method, tandem lamination method), (2) separately forming a laminate in which the adhesive layer 5 and the heat-sealable resin layer 4 are laminated, and laminating this on the barrier layer 3 of the laminate A by the thermal lamination method, or forming a laminate in which the adhesive layer 5 is laminated on the barrier layer 3 of the laminate A, and laminating this with the heat-sealable resin layer 4 by the thermal lamination method, (3) a method of bonding the laminate A and the heat-sealable resin layer 4 via the adhesive layer 5 while pouring the melted adhesive layer 5 between the barrier layer 3 of the laminate A and the heat-sealable resin layer 4 previously formed in a sheet shape (sandwich lamination method), (4) a method of laminating by solution coating and drying an adhesive for forming the adhesive layer 5 on the barrier layer 3 of the laminate A, and further by baking or the like, and laminating the heat-sealable resin layer 4 previously formed in a sheet shape on this adhesive layer 5, etc. can be mentioned.

[0139] When providing the surface coating layer 6, the surface coating layer 6 is laminated on the surface of the base material layer 1 opposite to the barrier layer 3. The surface coating layer 6 can be formed, for example, by applying the above resin for forming the surface coating layer 6 to the surface of the base material layer 1. The order of the step of laminating the barrier layer 3 on the surface of the base material layer 1 and the step of laminating the surface coating layer 6 on the surface of the base material layer 1 is not particularly limited. For example, after forming the surface coating layer 6 on the surface of the base material layer 1, the barrier layer 3 may be formed on the surface of the base material layer 1 opposite to the surface coating layer 6.

[0140] As described above, a laminate is formed that includes, in order from the outside, a surface coating layer 6 provided as necessary / a base material layer 1 / an adhesive layer 2 provided as necessary / a barrier layer 3 / an adhesive layer 5 provided as necessary / a heat-sealable resin layer 4. However, in order to strengthen the adhesiveness of the adhesive layer 2 and the adhesive layer 5 provided as necessary, it may be further subjected to a heat treatment.

[0141] In the exterior material for a power storage device, each layer constituting the laminate may be subjected to a surface activation treatment such as corona treatment, blast treatment, oxidation treatment, ozone treatment, etc. as necessary to improve the processability. For example, by subjecting the surface of the base material layer 1 on the side opposite to the barrier layer 3 to corona treatment, the printability of ink on the surface of the base material layer 1 can be improved.

[0142] The exterior material for a power storage device is preferably subjected to an aging treatment after laminating each layer. By changing the aging treatment conditions of the exterior material for a power storage device, the L * value, a * value, and b * value can be changed. Therefore, it is preferable to select the aging treatment conditions for the purpose of adjusting the L * value, a * value, and b * value. Examples of the adjustment items for the aging treatment conditions include the heating rate, heating temperature, heating time, presence or absence of pretreatment and its temperature, etc. Note that the main factor for the change in the L * value, a * value, and b * value due to the aging treatment conditions is that the degree of aggregation of the colorant contained in the exterior material for a power storage device changes depending on the aging treatment conditions.

[0143] 4. Use of Exterior Material for Energy Storage Device The exterior material for a power storage device of the present disclosure is used for a package for sealing and housing power storage device elements such as a positive electrode, a negative electrode, and an electrolyte. That is, a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte can be housed in a package formed by the exterior material for a power storage device of the present disclosure to obtain a power storage device.

[0144] Specifically, a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte is coated with the exterior material for a power storage device of the present disclosure in a state where metal terminals connected to each of the positive electrode and the negative electrode protrude outward so that a flange portion (a region where heat-sealable resin layers contact each other) can be formed at the periphery of the power storage device element, and the heat-sealable resin layers of the flange portion are heat-sealed and sealed, thereby providing a power storage device using the exterior material for a power storage device. When housing a power storage device element in a package formed by the exterior material for a power storage device of the present disclosure, the package is formed such that the heat-sealable resin portion of the exterior material for a power storage device of the present disclosure faces the inside (the surface in contact with the power storage device element).

[0145] The exterior material for a power storage device of the present disclosure can be suitably used for power storage devices such as batteries (including capacitors, capacitors, etc.). Further, the exterior material for a power storage device of the present disclosure can be used for either a primary battery or a secondary battery, but preferably a secondary battery. The type of secondary battery to which the exterior material for a power storage device of the present disclosure is applied is not particularly limited, and examples include lithium-ion batteries, lithium-ion polymer batteries, all-solid-state batteries, lead-acid batteries, nickel-metal hydride batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, metal-air batteries, polyvalent cation batteries, capacitors, capacitors, etc. Among these secondary batteries, lithium-ion batteries and lithium-ion polymer batteries are mentioned as suitable application targets for the exterior material for a power storage device of the present disclosure.

Examples

[0146] Examples and comparative examples are shown below to explain the present disclosure in detail. However, the present disclosure is not limited to the examples.

[0147] <Manufacture of Exterior Material for Power Storage Device> Examples 1 - 7, 14, 15 and Comparative Example 1 As the base material layer, a stretched nylon (ONy) film (thickness 15 μm) was prepared. Also, as the barrier layer, an aluminum foil (JIS H4160:1994 A8021H-O (thickness 35 μm)) was prepared. Next, the barrier layer and the base material layer were laminated by the dry lamination method using an adhesive (two-component urethane adhesive containing a colorant) described later, and then an aging treatment was carried out to produce a laminate of the base material layer / adhesive layer / barrier layer. Chemical conversion treatment was performed on both sides of the aluminum foil. The chemical conversion treatment of the aluminum foil was carried out by applying a treatment liquid composed of a phenol resin, a chromium fluoride compound, and phosphoric acid to both sides of the aluminum foil by the roll coating method so that the coating amount of chromium was 10 mg / m 2 (dry mass), and baking.

[0148] Next, maleic anhydride-modified polypropylene as an adhesive layer (thickness 20 μm) and random polypropylene as a heat-sealable resin layer (thickness 20 μm) were co-extruded onto the barrier layer of each laminate obtained above, so that the adhesive layer / heat-sealable resin layer was laminated on the barrier layer. Further, a resin composition containing silica particles (the resin is a polyurethane resin formed from a mixture of a polyol compound and an isocyanate compound) was applied to the surface of the base material layer of the obtained laminate to a thickness of 3 μm, thereby forming a matte-finished surface coating layer. In order from the outside, a laminate (total thickness 96 μm) in which a surface coating layer (3 μm) / base material layer (thickness 15 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer (20 μm) / heat-sealable resin layer (20 μm) was laminated was obtained.

[0149] Example 8 In Example 1, a laminate (total thickness: 93 μm) in which a base material layer (thickness: 15 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer (20 μm) / heat-fusible resin layer (20 μm) were laminated was obtained in the same manner as in Example 1, except that the surface coating layer was not formed.

[0150] Example 9 In Example 3, a laminate (total thickness: 93 μm) in which a base material layer (thickness: 15 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer (20 μm) / heat-fusible resin layer (20 μm) were laminated was obtained in the same manner as in Example 3, except that the surface coating layer was not formed.

[0151] Example 10 In Example 4, a laminate (total thickness: 93 μm) in which a base material layer (thickness: 15 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer (20 μm) / heat-fusible resin layer (20 μm) were laminated was obtained in the same manner as in Example 4, except that the surface coating layer was not formed.

[0152] Example 11 In Example 5, a laminate (total thickness: 93 μm) in which a base material layer (thickness: 15 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer (20 μm) / heat-fusible resin layer (20 μm) were laminated was obtained in the same manner as in Example 5, except that the surface coating layer was not formed.

[0153] Example 12 In Example 2, a laminate (total thickness: 93 μm) in which a base material layer (thickness: 15 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer (20 μm) / heat-fusible resin layer (20 μm) were laminated was obtained in the same manner as in Example 2, except that the surface coating layer was not formed.

[0154] Examples 13, 16 - 20 In Example 1, except that the surface coating layer was not formed and adhesives B, C4 to C8 shown in Table 1 were used instead of Adhesive A as the adhesive used for forming the adhesive layer, in the same manner as in Example 1, a laminate (total thickness: 93 μm) in which a base material layer (thickness: 15 μm) / adhesive layer (3 μm) / barrier layer (35 μm) / adhesive layer (20 μm) / heat-sealable resin layer (20 μm) were laminated was obtained.

[0155] <Adhesive> For forming the adhesive layer between the base material layer and the barrier layer, the following adhesives were used. Table 1 shows the types of adhesives used in each example and comparative example. [Adhesive A] A two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound) containing carbon black (secondary particle diameter: 0.2 μm) as a blackening agent [Adhesive B] A two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound) containing carbon black (secondary particle diameter: 0.2 μm) having a larger primary particle diameter than the carbon black contained in Adhesive A as a blackening agent [Adhesive C1] The same carbon black as the carbon black contained in Adhesive A was used as a blackening agent. A two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound) containing 4 parts by mass of copper phthalocyanine as a blueing agent with respect to 26 parts by mass of carbon black [Adhesive C2] The same carbon black as the carbon black contained in Adhesive A was used as a blackening agent. A two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound) containing 15 parts by mass of copper phthalocyanine as a blueing agent with respect to 15 parts by mass of carbon black [Adhesive C3] The same carbon black as the carbon black contained in Adhesive A was used as a blackening agent. A two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound) containing 17 parts by mass of copper phthalocyanine as a blueing agent with respect to 13 parts by mass of carbon black [Adhesive C4] As the black agent, the same carbon black as that contained in Adhesive A was used. A two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound) containing 10 parts by mass of copper phthalocyanine as a blue agent with respect to 20 parts by mass of carbon black [Adhesive C5] As the black agent, the same carbon black as that contained in Adhesive A was used. A two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound) containing 12 parts by mass of copper phthalocyanine as a blue agent with respect to 18 parts by mass of carbon black [Adhesive C6] As the black agent, the same carbon black as that contained in Adhesive A was used. A two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound) containing 8 parts by mass of copper phthalocyanine as a blue agent with respect to 22 parts by mass of carbon black [Adhesive C7] As the black agent, the same carbon black as that contained in Adhesive A was used. A two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound) containing 14 parts by mass of copper phthalocyanine as a blue agent with respect to 16 parts by mass of carbon black [Adhesive C8] As the black agent, the same carbon black as that contained in Adhesive A was used. A two-component urethane adhesive (a mixture of a polyol compound and an aromatic isocyanate compound) containing 16 parts by mass of copper phthalocyanine as a blue agent with respect to 14 parts by mass of carbon black

[0156] <Aging treatment conditions> Regarding the exterior materials for power storage devices manufactured in each example and comparative example, the aging treatment conditions used for adjusting the color observed from the outside are as follows. [Condition A] Leave it standing in an 80°C environment for 12 hours. [Condition B] First, as step 1, leave it standing at room temperature (about 25 °C) for 3 hours. Next, as step 2, leave it standing in an environment of 55 °C for 3 hours. Next, as step 3, leave it standing in an environment of 80 °C for 12 hours. [Condition C] Leave it standing in an environment of 60 °C to 100 °C for 3 days.

[0157] <L * Value, a * Value and b * Measurement of values> For the exterior materials for power storage devices obtained in each example and comparative example, the observation conditions of the spectrophotometer (CM-700d) manufactured by Konica Minolta calibrated with a white calibration cap (CM-A177: manufactured by Konica Minolta) were 10°, the observation light source was F2, SCI Set to the mode (JIS Z8722-2009), and measure L on the outer (base material layer side) surface * , a * , b * at normal temperature and humidity. The measurement was performed at 3 points for each sample, and the average value was shown in Table 1 as the evaluation result.

[0158] <Measurement of Cu element by X-ray fluorescence analysis (XRF)> For the exterior materials for power storage devices obtained in Examples 1 to 5 and Comparative Example 1, the presence or absence of detection of Cu element by X-ray fluorescence analysis (XRF) was confirmed under the following measurement conditions. As a result, in Examples 1, 2 and Comparative Example 1, peaks derived from Cu element were not detected. Also, in Examples 3, 4, 5, peaks derived from Cu element were detected. The peak intensity of CuKα was 0.4 for Example 3, 1.2 for Example 4, and 1.2 for Example 5. (Measurement conditions) Device used: EDX-800HS (manufactured by Shimadzu Corporation) X-ray: Rh target Voltage: 50 kV Current: 1000 μA Irradiation area: 100φ Measurement time: 100 sec Measurement atmosphere: vacuum Measurement surface: Outer side (X-rays are irradiated on the outer side of the exterior material for the power storage device) Analysis method: Automatic intensity calculation is performed using the software "PCEDX" attached to EDX-800HS (manufactured by Shimadzu Corporation). Specifically, peak detection is performed on the spectrum obtained by measurement. The coefficient of the peak detection condition is set to 10. Next, the detected intensity is calculated from the intensity calculation for the detected peak.

[0159] <Discriminability in the yellow room> On the surface of the surface coating layer of the exterior material for the power storage device obtained in each example and comparative example, a numerical sequence "0123456789" with a dot diameter of about 0.3 mm and a character string height of about 1.5 mm was printed using an inkjet printer (model name 9040, manufactured by Markem-Imaje Co., Ltd.) to obtain a sample. The ink used for printing was white. Next, in the yellow room, each sample was observed with the naked eye from a position 30 cm away, and the discriminability was evaluated according to the following evaluation criteria. The results are shown in Table 1. (Evaluation criteria) [[ID=I2]]A: Immediately recognizable B: Takes several seconds to recognize C: Can be recognized by changing the sample angle

[0160] <Black appearance> In a room under a fluorescent lamp, for each sample prepared in the <Discriminability in the yellow room> above, it was observed with the naked eye, and the evaluation was made on whether the appearance was recognized as black according to the following evaluation criteria. The results are shown in Table 1. (Evaluation criteria) A: Clearly recognized as black B: Slight blue or red is recognized, but it is recognized as black without problem C: Blue or red is clearly recognized, and there is a possibility that it is not recognized as black

[0161]

Table 1

[0162] As is clear from the results shown in Table 1, the packaging materials for electricity storage devices of Examples 1 to 20 had a low L of reflected light measured from the outside under the measurement conditions of the SCI method, a field of view of 10°, and a light source of F2. * a * b * b in color space * Since the value was -0.20 or less, it can be seen that, despite the electrical storage device packaging materials having a black appearance, the identification marks printed on the surfaces were excellent in the identification of the identification marks printed on the surfaces in a yellow room. The electrical storage device packaging materials of Examples 1 to 20 had excellent identification of the identification marks printed on the surfaces not only in a yellow room but also indoors under ordinary fluorescent lighting. Furthermore, the electrical storage device packaging materials of Examples 1 to 20 could be recognized without any problem as having a black appearance indoors under ordinary fluorescent lighting.

[0163] As described above, the present disclosure provides the following aspects of the invention. Item 1. An exterior packaging material for an electricity storage device that has a black appearance, the electrical storage device packaging material is composed of a laminate including, in order from the outside, at least a base layer, a barrier layer, and a heat-sealable resin layer; The L of reflected light measured from the outside of the laminate under the measurement conditions of SCI method, field of view 10° and light source F2 * a * b * b in color space * An exterior material for an electricity storage device, wherein the value is -0.20 or less. Item 2. The L of reflected light measured from the outside of the laminate under the measurement conditions of SCI method, field of view 10° and light source F2 * a * b * a in color space * Item 2. The packaging material for an electricity storage device according to Item 1, wherein the value is +0.2 or less. Item 3. An adhesive layer is provided between the base layer and the barrier layer, Item 3. The electrical storage device packaging material according to Item 1 or 2, wherein the adhesive layer contains a colorant. Item 4. A colored layer is provided between the substrate layer and the barrier layer, The exterior material for a power storage device according to any one of items 1 to 3, wherein the colored layer contains a pigment. Item 5. The exterior material for a power storage device according to any one of items 1 to 4, further comprising a surface coating layer on the side opposite to the barrier layer side of the base material layer. Item 6. When analyzing from the outside of the laminate by X-ray fluorescence analysis, Cu element is detected. The exterior material for a power storage device according to any one of items 1 to 5. Item 7. A method for manufacturing an exterior material for a power storage device having a black appearance, comprising a step of obtaining a laminate in which at least a base material layer, a barrier layer, and a heat-sealable resin layer are laminated in this order from the outside. The L of the reflected light measured from the outside of the laminate under the measurement conditions of SCI method, a viewing angle of 10°, and a light source F2 * a * b * in the color space of b * value is -0.20 or less. A method for manufacturing an exterior material for a power storage device. Item 8. A power storage device in which a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the exterior material for a power storage device according to any one of items 1 to 6.

Explanation of symbols

[0164] 1 Base material layer 2 Adhesive layer 21 Colored layer 3 Barrier layer 4 Heat-sealable resin layer 5 Adhesive layer 6 Surface coating layer 10 Exterior material for a power storage device

Claims

1. An exterior material for a power storage device whose appearance exhibits black color, The exterior material for a power storage device is composed of a laminate including at least a base material layer, a barrier layer, and a heat-sealable resin layer, in this order from the outside, L of the reflected light measured from the outside of the laminate under the measurement conditions of the SCI method, a viewing angle of 10°, and a light source F2 * a * b * b value in the color space * is -5.00 or more and -0.20 or less, The a* value in the L*a*b* color space of the reflected light is -3.50 or more and +0.20 or less, The L* value in the L*a*b* color space of the reflected light is 40 or less. An exterior material for a power storage device.

2. L of the reflected light measured from the outside of the laminate under the measurement conditions of the SCI method, a viewing angle of 10°, and a light source F2 * a * b * a in the color space * The exterior material for a power storage device according to claim 1, wherein the value is +0.10 or less

3. An adhesive layer is provided between the base material layer and the barrier layer, The exterior material for a power storage device according to claim 1 or 2, wherein the adhesive layer contains a colorant.

4. A colored layer is provided between the base material layer and the barrier layer, The exterior material for a power storage device according to any one of claims 1 to 3, wherein the colored layer contains a pigment.

5. A surface coating layer is provided on the side of the base material layer opposite to the barrier layer side. The exterior material for a power storage device according to any one of claims 1 to 4.

6. When analysis is performed on the outside of the laminate by fluorescent X-ray analysis, a Cu element is detected. The exterior material for a power storage device according to any one of claims 1 to 5.

7. L of the reflected light * a * b * b in the color space * The exterior material for a power storage device according to any one of claims 1 to 6, wherein the value is -1.20 or more.

8. L of the reflected light * a * b * a in the color space * The exterior material for a power storage device according to any one of claims 1 to 7, wherein the value is -0.07 or more.

9. A lubricant is present on the surface of the heat-sealable resin layer, The amount of the lubricant present is 10 mg / m 2 or more. The exterior material for a power storage device according to any one of claims 1 to 8.

10. At least one of the surface and the inside of the heat-sealable resin layer has two or more kinds of lubricants. The exterior material for a power storage device according to any one of claims 1 to 9.

11. At least two or more selected from the group consisting of saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides are present in at least one of the surface and the inside of the heat-sealable resin layer. The exterior material for a power storage device according to any one of claims 1 to 10.

12. A surface coating layer is provided on the side of the base material layer opposite to the barrier layer, At least one of the surface and the inside of the surface coating layer has a lubricant. The exterior material for a power storage device according to any one of claims 1 to 11.

13. A surface coating layer is provided on the side of the base material layer opposite to the barrier layer, At least one of the surface and the inside of the surface coating layer has two or more kinds of lubricants. The exterior material for a power storage device according to any one of claims 1 to 12. b

14. A surface coating layer is provided on the side opposite to the barrier layer of the base material layer. On at least one of the surface and the interior of the surface coating layer, there are present at least two or more selected from the group consisting of saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, methylol amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, and aromatic bisamides. The exterior material for a power storage device according to any one of claims 1 to 13.

15. A method for manufacturing an exterior material for a power storage device having a black appearance, comprising: A step of obtaining a laminate in which at least a base material layer, a barrier layer, and a heat-sealable resin layer are laminated in order from the outside. L of the reflected light measured from the outside of the laminate under the measurement conditions of the SCI method, a viewing angle of 10°, and a light source F2 * a * b * b value in the color space * is -5.00 or more and -0.20 or less, The a* value in the L*a*b* color space of the reflected light is -3.50 or more and +0.20 or less. The L* value in the L*a*b* color space of the reflected light is 40 or less. A method for manufacturing an exterior material for a power storage device.

16. An adhesive layer is provided between the barrier layer and the heat-sealable resin layer. The barrier layer and the heat-sealable resin layer are formed by a coextrusion lamination method, a tandem lamination method, a thermal lamination method, a sandwich lamination method, or by solution-coating an adhesive for forming the adhesive layer on the barrier layer and laminating the heat-sealable resin layer previously formed in a sheet shape on the adhesive layer. The method for manufacturing an exterior material for a power storage device according to claim 15.

17. A power storage device in which a power storage device element including at least a positive electrode, a negative electrode, and an electrolyte is housed in a package formed of the exterior material for a power storage device according to any one of claims 1 to 14.

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