CN116096572A - Outer packaging material for electrical storage equipment, electrical storage equipment, and manufacturing method of outer packaging material for electrical storage equipment - Google Patents

Abstract

The outer packaging material (1) for the power storage device comprises a base material layer (3), a metal layer (2), and a sealant layer (4). Arithmetic mean curvature Spc (unit: mm) of peak apex in inner side surface (1 a) of outer packaging material (1) ^‑1 ) Five-point peak area height S5p (μm), smooth coarse cross SRC (μm) ² ) The region typing complexity Safc (dimensionless), the height difference Sk (μm) of the core, the pole height Sxp (μm), the root mean square slope Sdr (%), the minimum autocorrelation length Sal (μm), the volume Vvc (mL/m) of the space of the core ² ) Volume of core Vmc (mL/m ² ) When a to j are defined, the value of F defined by the following formula 1 is greater than 0. F= -6.0-0.13a-0.51b+0.000073c-3.9d+0.91e+1.5f-3.9g+0.027h+2.1i+2.3j … (formula 1).

Description

Outer packaging material for electrical storage equipment, electrical storage equipment, and manufacturing method of outer packaging material for electrical storage equipment

technical field

The present invention relates to outer packaging materials for electric storage devices such as batteries and capacitors used in portable devices (such as smartphones and tablet computers), electric vehicles (including hybrid cars), electric storage devices, and outer packaging materials for electric storage devices manufacturing method.

Background technique

In a battery as an electrical storage device, for example, the battery main body, which is the main body of the electrical storage device, is packaged with an outer packaging body. As this outer wrapping material, there is known an outer wrapping material formed of a laminate comprising a substrate layer as an outer layer, a sealant layer as an inner layer, and a sealant layer disposed between these two layers as The metal layers of the barrier layer are arranged in a stacked form.

In the outer packaging material, the base material layer and the sealant layer are each formed of a predetermined resin, and the metal layer is formed of a predetermined metal foil (for example, aluminum foil). Usually, the substrate layer and the metal layer are bonded to each other by an adhesive layer interposed between these two layers, and the metal layer and the sealant layer are bonded to each other by an adhesive layer interposed between these two layers.

When the battery main body (power storage device main body) is packaged by the outer packaging material, since the outer packaging material forms a space for accommodating the battery main body, the outer packaging material has a predetermined shape such as a container shape. Carry out prescribed forming processes such as bulge forming process and deep drawing process.

In order to improve the molding processability of the outer packaging material at this time, Patent Document 1 discloses that the arithmetic average roughness (center line average roughness) Ra of the surface of the sealant layer as the inner surface of the outer packaging material is 0.05 μm to 1 μm. In addition, Patent Document 2 discloses that the surface of the sealant layer, which is the inner surface of the outer packaging material, has a concavo-convex shape, and its arithmetic average roughness Ra is 3.0 μm to 20.0 μm.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2018-73649

Patent Document 2: Japanese Patent Laid-Open No. 2017-112014

Contents of the invention

The problem to be solved by the invention

However, after the outer packaging material has been molded into a predetermined shape as described above, blisters (convex deformation and swelling) may occur on the outer surface of the outer packaging material. The inventors of the present application conducted intensive studies and experiments to find out the cause of the bubbles (Japanese: フクレ) as follows.

That is, in order to improve the various strengths of the outer packaging material (such as the adhesive strength of the adhesive layer) and aging the outer packaging material, usually the outer packaging material produced by winding the outer packaging material into a roll The volume is aged. In addition, when storing and transporting the outer packaging material, the outer packaging material roll produced by winding the outer packaging material is usually also stored and transported.

When winding the wrapping material to produce the wrapping material roll, the wrapping material is wound into a roll with high tension applied to the wrapping material in order to avoid winding misalignment at the center of the wrapping material roll. At this time, a large amount of air may be enclosed between the wound packaging materials. If the outer wrapping material roll is aged with air sealed between the outer wrapping materials, or the outer wrapping material roll is exposed to high temperature during storage and transportation of the outer wrapping material roll, the air layer sealed between the outer wrapping materials will thermally expand and Compress the outer packaging material. Then, when the temperature of the wrapping material roll returns to room temperature or the tension of the wrapping material in the wrapping material roll is relaxed, the air layer disappears. Thus, the base material layer and sealant layer of the outer packaging material are formed of resin, so they can be restored to their original shape by the restoring force of the resin, but since the metal layer of the outer packaging material is difficult to restore, the metal layer remains. Indentation caused by thermal expansion. This indentation serves as a starting point for blisters to be generated in the molded packaging material. The above situation was found out.

Therefore, the inventors of the present application considered and adjusted the calculated average roughness Ra of the inner surface and the outer surface of the outer packaging material in order to prevent air from being trapped between the outer packaging materials of the outer packaging material roll.

Here, the inventions of the above-mentioned Patent Documents 1 and 2 are not intended to prevent air from being trapped between the outer wrapping materials of the outer wrapping material roll, but for the calculation of the average roughness Ra of the inner surface and the outer surface of the outer wrapping material as The inventors of the present application conceived and conducted experiments to obtain the effect of avoiding the encapsulation of air between the outer packaging materials within the scope disclosed in Patent Documents 1 and 2, but a sufficient effect could not be obtained.

The present invention was made in view of the above-mentioned technical background, and an object of the present invention is to provide an electrical storage device outer packaging material capable of suppressing blisters after molding, an electrical storage device using the outer packaging material, and an electrical storage device outer packaging The method of manufacture of the material.

Other objects and advantages of the present invention will be apparent from the following preferred embodiments.

means to solve the problem

The present invention provides the following aspects.

1) An outer packaging material for an electrical storage device, comprising a base material layer as an outer layer, a sealant layer as an inner layer, and a metal layer as a barrier layer arranged between these two layers,

The arithmetic mean curvature Spc (unit: mm ^-1 ) of the peak apex measured based on ISO25178, the height of the five-point peak area S5p (unit: μm), the smooth and rough cross SRC (unit: μm ^{2 )} in the inner surface of the outer packaging material ), regional typing complexity Safc (unit: dimensionless), core height difference Sk (unit: μm), pole height Sxp (unit: μm), root mean square slope Sdr (unit: %), minimum autocorrelation When the length Sal (unit: μm), the volume Vvc (unit: mL/m ² ) of the core space, and the volume Vmc (unit: mL/m ² ) of the core are respectively a to j,

The value of F defined by Formula 1 below is greater than zero.

F=-6.0-0.13a-0.51b+0.000073c-3.9d+0.91e+1.5f-3.9g+0.027h+2.1i+2.3j... (Formula 1).

2) The outer packaging material for an electrical storage device according to 1 above, wherein the arithmetic mean curvature Spc of the peak apex is in the range of -40 mm ^-1 to -500 mm ^-1 .

3) The outer packaging material for an electrical storage device according to the above 1 or 2, wherein the sealant layer is formed of a multilayer film containing polypropylene.

4) An electrical storage device, wherein the main body of the electrical storage device is packaged with the outer packaging material for an electrical storage device according to any one of 1 to 3 above.

5) A method of manufacturing an outer packaging material for an electrical storage device, the outer packaging material for an electrical storage device comprising a base material layer as an outer layer, a sealant layer as an inner layer, and a barrier layer disposed between these two layers. layer metal layer,

The arithmetic mean curvature Spc (unit: mm ^-1 ) of the peak apex measured based on ISO25178, the height of the five-point peak area S5p (unit: μm), the smooth and rough cross SRC (unit: μm ^{2 )} in the inner surface of the outer packaging material ), regional typing complexity Safc (unit: dimensionless), core height difference Sk (unit: μm), pole height Sxp (unit: μm), root mean square slope Sdr (unit: %), minimum autocorrelation When the length Sal (unit: μm), the volume Vvc (unit: mL/m ² ) of the core space, and the volume Vmc (unit: mL/m ² ) of the core are respectively a to j,

Select an outer packaging material whose value of F defined by the following formula 1 is greater than 0 from a plurality of outer packaging materials,

The selected outer wrapping material is aged in a rolled state.

F=-6.0-0.13a-0.51b+0.000073c-3.9d+0.91e+1.5f-3.9g+0.027h+2.1i+2.3j... (Formula 1).

Invention effect

The present invention has the following effects.

In the aforementioned 1, in the case where the value of F defined by the above formula 1 is greater than 0, the inner surface of the outer wrapping material has a moderate concave-convex shape, and since the outer wrapping material is restrained from forming a bond with each other when the outer wrapping material is wound into a roll, The tightness makes it difficult for air to be sealed between the outer packaging materials. Therefore, it is possible to suppress generation of blisters on the outer surface of the exterior material after molding the exterior material into a predetermined shape.

In the above-mentioned 2, since air is not easily enclosed between the outer wrapping materials of the outer wrapping material roll, it is possible to reliably suppress the occurrence of indentations in the outer wrapping material. Accordingly, it is possible to reliably suppress the occurrence of blisters in the outer packaging material.

In the above-mentioned 3, it is possible to easily join the part to be joined of the outer wrapping material by heat sealing after the molding process of the outer wrapping material.

In the aforementioned 4, it is possible to provide an electrical storage device packaged with a package material in which generation of blisters is suppressed.

In the aforementioned 5, it is possible to reliably obtain an outer packaging material capable of suppressing generation of bubbling after molding processing.

Description of drawings

FIG. 1 is a schematic cross-sectional view of an exterior material for an electrical storage device according to one embodiment of the present invention.

Fig. 2 is a schematic side view of an outer wrapping material roll produced by winding an outer wrapping material into a roll.

Fig. 3 is a schematic cross-sectional view of an electrical storage device according to an embodiment of the present invention.

Fig. 4 is a schematic perspective view illustrating the power storage device in disassemble.

Detailed ways

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1 , an exterior material 1 for an electrical storage device according to an embodiment of the present invention is formed of a laminate comprising a base material layer 3 as an outer layer, a sealant layer 4 as an inner layer, and the metal layer 2 as a barrier layer arranged between these two layers 3 and 4 are arranged in a laminated form. It should be noted that the reference numeral “1a” in FIG. 1 is the inner surface of the outer packaging material 1 , and the reference numeral “1b” is the outer surface of the outer packaging material 1 .

In the exterior material 1, the base material layer 3, the metal layer 2, and the sealant layer 4 are sequentially bonded and integrated in a laminated form. Specifically, the base material layer 3 and the metal layer 2 are bonded to each other through the first adhesive layer 5a by, for example, a dry lamination method, and the metal layer 2 and the sealant layer 4 are bonded to each other by, for example, a dry lamination method through the first adhesive layer 5a. 2. The adhesive layer 5b adheres to each other.

The outer wrapping material 1 is usually in the shape of a long strip, and the outer wrapping material 1 is cut into a predetermined length and a predetermined shape before wrapping the main body of the electrical storage device with the outer wrapping material 1 .

When storing and transporting the outer packaging material 1 , as shown in FIG. 2 , the outer packaging material roll 10 produced by winding the outer packaging material 1 into a roll shape is usually stored and transported. During this storage and transportation, the outer wrapping material roll 10 may be exposed to a temperature higher than room temperature (25° C.) such as 35° C. to 70° C.

In addition, in order to improve the various strengths of the outer packaging material 1 (such as the adhesive strength of the adhesive layer 5a, 5b), when the outer packaging material 1 is aged, it is still necessary to wind the outer packaging material 1 into a roll. Shape and the outer packaging material roll 10 that makes is aged. At this time, for aging (specifically, artificial aging), the wrapping material roll 10 is exposed to a temperature higher than room temperature of 35° C. to 65° C. using a predetermined aging device.

Here, in the present embodiment, three-dimensional surface texture parameters (Spc, S5p, SRC, Safc, Sk, Sxp, Sdr, Sal, Vvc, and Vmc) measured in accordance with ISO25178 on the inner surface 1a of the outer packaging material 1 are used. value, F is defined by Equation 1 below.

F=-6.0-0.13a-0.51b+0.000073c-3.9d+0.91e+1.5f-3.9g+0.027h+2.1i+2.3j... (Formula 1).

In Formula 1, a to j represent the values of the following three-dimensional surface texture parameters, and the units in each parenthesis.

a: Arithmetic mean curvature Spc of peak apex (Japanese: Arithmetic mean curvature Spc of mountain top) (unit: mm ^-1 )

b: Height S5p of Wudian Peak Area (Japanese: Wudianshan Area Height さS5p) (unit: μm)

c: Smooth rough cross SRC (Japanese: スムースラフクロスオーバー SRC) (unit: μm ² )

d: Area classification complexity Safc (Japanese: エリアルフラクタルコンプレキシティーSafc) (unit: dimensionless)

e: The height difference Sk of the core (Japanese: コアブのレベル差Sk) (unit: μm)

f: pole height Sxp (Japanese: pole height さSxp) (unit: μm)

g: root mean square slope Sdr (unit: %)

h: minimum autocorrelation length Sal (unit: μm)

i: Volume Vvc of the space in the core (unit: mL/m ² )

j: volume Vmc of the core (unit: mL/m ² ).

In the outer packaging material 1 of the present embodiment, the value of F (hereinafter also referred to as "F value") must be greater than 0 (that is, F>0).

When the F value is greater than 0, the inner side surface 1a of the outer packaging material 1 has a moderate concave-convex shape, and when the outer packaging material 1 is wound into a roll shape, the close adhesion of the outer packaging materials 1 and 1 can be suppressed, and the air It is difficult to be enclosed between the outer packaging materials 1,1. Therefore, even when the wrapping material roll 10 is exposed to a high temperature state as described above, it is possible to suppress generation of indentations in the wrapping material 1 (specifically, the metal layer 2 of the wrapping material 1 ). Thereby, it is possible to suppress generation of blisters on the outer surface 1b of the exterior material 1 after molding the exterior material 1 into a predetermined shape. The upper limit of the F value is not limited, and is usually 10 or less.

In addition, it is preferable that the arithmetic mean curvature Spc of the peak apex is in the range of -40 mm ^-1 to -500 mm ^-1 . In this case, it is difficult for air to be reliably enclosed between the outer wrapping materials 1 and 1 of the outer wrapping material roll 10 , and thus it is possible to reliably suppress the occurrence of indentations in the outer wrapping material 1 . Accordingly, it is possible to reliably suppress the occurrence of blisters in the outer packaging material 1 . A particularly preferable range of Spc is -40mm ^-1 to -100mm ^-1 .

Here, the term "bubble" refers to convex deformation and swelling that occurs on the outer surface 1b of the outer packaging material 1 after the outer packaging material 1 is molded into a predetermined shape such as a container shape. The size (diameter) of the bubbles is usually 10 mm or more.

The value of the above-mentioned three-dimensional surface texture parameter is measured based on ISO25178 as described above, specifically, by white light interference microscopy (vertical scanning low-coherence interferometry) or the like.

Next, the base material layer 3 , the metal layer 2 , and the sealant layer 4 constituting the exterior material 1 will be described below.

<Substrate layer 3>

The base material layer 3 is formed of a resin, specifically, a resin or the like having heat resistance at a temperature at the time of heat welding via the sealant layer 4 . Specifically, it is preferable that the substrate layer 3 is made of a biaxially stretched polyamide film, a biaxially stretched polybutylene terephthalate (PBT) film, a biaxially stretched polyethylene terephthalate Polyester (PET) film, biaxially stretched polyethylene naphthalate (PEN) film, etc. As the above-mentioned polyamide film, 6 nylon film, 6,6 nylon film, MXD nylon film, etc. can be used. In addition, the base material layer 3 is not necessarily formed of a film, and may be formed of, for example, a resin coating. It should be noted that the base material layer 3 may be formed of a single layer or may be formed of multiple layers.

In addition, the base material layer 3 is preferably formed of a resin having a melting point higher by 10° C. or more than all the resins constituting the sealant layer 4 , and particularly preferably formed of a resin having a melting point higher than 20° C. or more.

The thickness of the base material layer 3 is not limited, but is preferably 9 μm to 50 μm.

It should be noted that a matte coating (not shown) or the like may be formed on the outer surface of the base material layer 3 .

＜Metal layer 2＞

The metal layer 2 is made of metal foil or the like. Specifically, the metal layer 2 is formed of aluminum foil, copper foil, stainless steel foil, titanium foil, nickel foil, clad foil, or the like.

When the metal layer 2 is formed of a metal foil, it is preferable to form a base treatment layer (not shown) such as a chemical conversion treatment layer on at least one of both surfaces of the metal foil (particularly preferably the surface on the sealant layer 4 side). In this case, it is possible to suppress corrosion of the metal layer 2 caused by content in the battery device body (for example, electrolyte solution in the battery body).

The chemical conversion treatment to metal foil is performed, for example, by the following method. That is, after the surface of the degreasing metal foil is coated with any one of the following 1) to 3) aqueous solutions, the chemical conversion treatment is carried out by drying:

1) contains: phosphoric acid;

chromic acid; and

An aqueous solution of a mixture of at least one compound selected from the group consisting of metal salts of fluorides and non-metallic salts of fluorides,

2) contains: phosphoric acid;

at least one resin selected from the group consisting of acrylic resins, chitosan derivative resins, and phenolic resins; and

an aqueous solution of a mixture of at least one compound selected from the group consisting of chromic acid and chromium (III) salts,

3) contains: phosphoric acid;

at least one resin selected from the group consisting of acrylic resins, chitosan derivative resins, and phenolic resins;

at least one compound selected from the group consisting of chromic acid and chromium(III) salts; and

An aqueous solution of a mixture of at least one compound selected from the group consisting of metal salts of fluorides and non-metallic salts of fluorides.

The thickness of the metal layer 2 is not limited, but is preferably 20 μm to 100 μm.

<Sealant layer 4>

The sealant layer 4 is formed of thermoplastic resin (for example, polyolefin-based resin) or the like. Specifically, the sealant layer 4 is formed of a polyolefin film or the like. As the polyolefin film, a non-stretched polypropylene (CPP) film or the like can be used. In addition, when the sealant layer 4 is formed of a film, the film which forms the sealant layer 4 is also called a sealant film hereinafter.

In addition, the sealant layer 4 may be composed of a single layer, and particularly, as shown in FIG. 1 , is preferably formed of a multilayer, and is more preferably formed of a multilayer film. When the number of layers of the multilayer film is two, the multilayer film has an innermost layer 4a arranged on the inner surface 1a side of the outer packaging material 1, and an outermost layer 4b arranged on the metal layer 2 side of the outer packaging material 1. When the number of layers of the multilayer film is three or more, the multilayer film has the above-mentioned innermost layer 4a and outermost layer 4b, and at least one intermediate layer (not shown) disposed between these two layers 4a, 4b. Show).

Furthermore, it is preferred that the multilayer film is formed of polypropylene. In this case, the portion to be joined of the exterior material 1 can be easily joined by heat sealing after molding the exterior material 1 . More preferably, the multilayer film is integrated in a state where two or more layers of a random polypropylene copolymer (rPP) layer and a polypropylene block copolymer (bPP) layer are laminated. In particular, it is preferable that the rPP layer is arranged as the innermost layer 4 a of the sealant layer 4 among the layers constituting the sealant layer 4 .

The thickness of the sealant layer 4 is not limited, but is preferably 20 μm to 100 μm.

In addition, it is preferable that the sealant layer 4 includes a lubricant-containing layer. In this case, the friction between the outer packaging materials 1 and 1 of the outer packaging material roll 10 is reduced, so it is possible to suppress damage to the inner surface 1a and the outer surface 1b of the outer packaging material 1 wound in a roll shape, and ensure reliable operation. Air can be prevented from being enclosed between the outer packaging materials 1 and 1 as much as possible, so it is possible to reliably suppress the generation of bubbles in the outer packaging material 1 . In particular, it is preferable that the lubricant-containing layer in the sealant layer 4 is arranged as at least the innermost layer 4 a of the sealant layer 4 . In this case, the above-mentioned effects of the lubricant can be reliably exhibited.

＜Lubricant＞

The lubricant is used to improve the sliding properties of the outer packaging material 1 when the outer packaging material 1 is molded, thereby improving the molding processability of the outer packaging material 1, and is used to reduce the friction when the outer packaging material 1 is wound into a roll. The friction between the outer wrapping materials 1 and 1 of the outer wrapping material roll 10 suppresses damage to the inner surface 1 a and the outer surface 1 b of the outer wrapping material 1 . A lubricant is generally contained in the sealant layer (resin) 4 by being added to the resin forming the sealant layer 4 .

Specifically, as lubricants, saturated fatty acid amides (such as lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide), unsaturated fatty acid amides (such as oleic acid amide, erucamide), substituted amides (such as N-oleyl palmitamide, N-stearyl stearamide, N-stearyl oleamide, N-oleyl stearamide, N-stearyl erucamide), methylolamides (e.g. hydroxymethylstearamide), saturated fatty acid bisamides (e.g. methylenebisstearamide, ethylenebiscapricamide, ethylenebislauricamide , ethylene bis stearic acid amide, ethylene bis hydroxystearic acid amide, ethylene bis behenic acid amide, hexamethylene bis stearic acid amide, hexamethylene bis behenic acid amide, six Methylene hydroxystearic acid amide, N,N'-distearyl adipamide, N,N'-distearyl sebacic acid amide), unsaturated fatty acid bisamides (e.g. ethylene bis-oil acid amide, ethylenebiserucamide, hexamethylenebisoleamide, N,N'-dioleyl adipamide, N,N'-dioleyl sebacate), fatty acid ester Amides (such as stearamide ethyl stearate), aromatic bisamides (such as m-xylyl bis-stearic acid amide, m-xylyl bis-hydroxy stearic acid amide, N,N'-di stearyl isophthalic acid amide), etc.

The content of the lubricant is not limited. When the sealant layer 4 is composed of a single layer, the content of the lubricant is preferably in the range of 100 ppm to 7000 ppm relative to the sealant layer 4. In addition, when the sealant layer 4 is formed of multiple layers and When at least the innermost layer 4 a of the sealant layer 4 contains a lubricant, the content of the lubricant is preferably in the range of 100 ppm to 7000 ppm relative to the innermost layer 4 a of the sealant layer 4 .

Here, when the sealant layer 4 of the outer packaging material 1 has a lubricant, if the outer packaging material roll 10 is exposed to a high temperature state as described above, the lubricant in the sealant layer 4 of the outer packaging material 1 will remain in the outer packaging. The inner surface 1a of the material 1 seeps out slightly, forming a very thin lubricant layer (not shown) on the inner surface 1a, and the lubricant that seeps out is further transferred to the outer surface 1b of the outer packaging material 1, where A very thin lubricant layer (not shown) is also formed on the outer surface 1b.

However, the thickness of each lubricant layer is usually several nm, so the inventors of the present application confirmed that the presence of each lubricant layer hardly affects the value of the above-mentioned three-dimensional surface texture parameter and the F value.

<Adhesive layer 5a, 5b>

The adhesive of the first adhesive layer 5a is not limited, and specifically, adhesives such as polyurethane resins, epoxy resins, and acrylic resins (including two-component curing adhesives) can be exemplified. ).

The adhesive of the second adhesive layer 5b is not limited, and specifically, adhesives such as olefin-based resins, acid-modified olefin-based resins, and epoxy-based resins (including two-component curing types) can be exemplified. glue).

The method of applying each adhesive bond layer 5a, 5b to the corresponding surface of the metal layer 2 is not limited, For example, the method of applying each adhesive bond layer 5a, 5b by gravure coating is mentioned.

Here, a method for reliably obtaining a packaging material that suppresses the generation of blisters after molding is as follows.

That is, an outer wrapping material having an F value larger than 0 is selected from a plurality of outer wrapping materials, and the selected outer wrapping material is aged in a state wound in a roll. Thereby, it is possible to reliably obtain an outer packaging material in which generation of blisters can be suppressed after molding. The aging conditions at this time are not limited, but the aging temperature is preferably 30°C to 50°C. In this case, various strengths of the exterior material 1, such as the adhesive strength of the adhesive layer 5a, 5b, can be improved reliably. The aging time is, for example, 3 days to 14 days.

In addition, a method for reliably obtaining the outer packaging material 1 with an F value greater than 0 is as follows.

That is, the value of the three-dimensional surface texture parameter of the inner surface 1a of the outer packaging material 1 mainly depends on the uneven shape of the surface of the sealant film (sealant layer 4) side of the second adhesive layer 5b and the inner surface of the sealant film. surface properties. Therefore, a combination of the uneven shape of the surface of the second adhesive layer 5b and the surface texture of the inner surface of the sealant film is designed in advance through experiments in which the F value is greater than 0, and the outer packaging material can be produced reliably by using this combination. Obtain the outer packing material whose F value is greater than 0. In addition, the said inside surface of the sealant film is the surface of the side which becomes the inside surface 1a of the exterior material 1 among both surfaces of the sealant film.

The method of designing the concavo-convex shape of the surface of the second adhesive layer 5b is not limited. For example, when the second adhesive layer 5b is applied to the surface of the metal layer 2 by gravure coating, it can be applied by gravure coating. The concavo-convex shape of the surface of the second adhesive layer 5b is designed by adjusting conditions (for example, the grid shape, the number of lines, and the depth of the gravure roll).

The surface properties of the inner surface of the sealant film can be designed by adjusting the amount of the anti-blocking agent added to the film, molding the film, and the like.

As shown in FIGS. 3 and 4 , the exterior material 1 of the present embodiment is used for exterior packaging of, for example, a lithium ion secondary battery 25 as an electrical storage device.

As shown in FIG. 4 , lithium ion secondary battery 25 includes a substantially rectangular parallelepiped battery body 24 serving as an electrical storage device body, and an outer container 20 housed in a state surrounding battery body 24 . The outer packaging container 20 includes an outer packaging container main body 21 and an outer packaging cover body 22 corresponding to the outer packaging container main body 21 .

The outer container main body 21 is formed into a container shape by predetermined molding processing (eg, bulge molding, deep drawing) with the inner surface 1 a of the outer packaging material 1 of the above embodiment facing inward. A recess 21b for accommodating the battery body 24 is formed at the center of the inner surface 1a of the outer container body 21, and a flange portion 21a curved outward as a planned joining portion is formed at the outer periphery of the outer container body 21.

The exterior cover 22 is used in a flat state without molding the exterior material 1 of the above-mentioned embodiment.

In the battery 25, as shown in FIG. 3 , the battery main body 24 is accommodated in the recess 21b of the outer container main body 21, and the outer packaging lid 22 is arranged on the outer packaging so that the inner surface 1a faces the battery main body 24 side (lower side). On the container body 21, the sealant layer 4 (see FIG. 1 ) of the flange portion 21a (part to be joined) of the outer container body 21 and the sealant layer 4 (refer to FIG. The layers 4 (see FIG. 1 ) are bonded in a hermetically sealed state by heat sealing (thermal welding), thereby forming a battery 25 in a state where the battery main body 24 is surrounded by the outer packaging container 20 (outer packaging material 1 ).

It should be noted that reference numeral "23" in FIG. 3 is a joint portion of the sealant layer 4 of the flange portion 21a of the outer container body 21 and the sealant layer 4 of the outer peripheral portion 22a of the outer cover body 22 ( thermal welding part).

In the battery 25 , the inner surface 1 a of the outer packaging material 1 forming the outer packaging container body 21 faces the battery body 24 side, and the inner surface 1 a of the outer packaging material 1 forming the outer packaging lid 22 also faces the battery main body 24 side.

It should be noted that the front end portion of the tab lead connected to the battery main body 24 is led out to the outside of the outer packaging container 20, and in FIGS. 3 and 4 , the illustration of the tab lead is omitted.

One embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and various changes can be made within a range not departing from the gist of the present invention.

In addition, in the present invention, the power storage device main body packaged by the outer packaging material is not limited to the battery main body of various batteries such as lithium-ion secondary batteries, and may also be the electrolytic capacitor main body of other various electrolytic capacitors (capicitor), Capacitor body of various capacitors (condenser), etc.

Example

Specific examples and comparative examples of the present invention are shown below. However, the present invention is not limited to the following examples.

＜Example and Comparative Example＞

A strip-shaped aluminum foil (material: A8021-O (specified by JIS H4160)) having a thickness of 40 μm was prepared as the metal layer. Furthermore, a chromate treatment was performed on both surfaces of the aluminum foil to form a chemical conversion coating as a base treatment layer.

Next, on one surface of the aluminum foil, a 25-μm-thick strip of the substrate layer was bonded by dry lamination via a two-component curing polyurethane-based adhesive layer (first adhesive layer). A biaxially stretched 6 nylon film and wound into a roll. Bonding based on the dry lamination method is performed by pinching aluminum foil and biaxially stretched 6 nylon film between rubber nip rolls and lamination rolls heated to 100°C. In addition, application of the first adhesive layer on one surface of the aluminum foil was performed by gravure coating.

Then, the above-mentioned aluminum foil wound into a roll was aged at 60° C. for 7 to 10 days.

Next, on the other surface of the aluminum foil, the thickness of the adhesive sealant layer is formed by dry lamination through a two-component curing type maleic acid-modified polypropylene adhesive layer (second adhesive layer). 80μm long strip-shaped sealant film, and wound into a roll. Bonding based on dry lamination is performed by pinching aluminum foil and sealant film between rubber nip rolls and lamination rolls heated to 100°C. In addition, the application of the second adhesive layer to the other surface of the aluminum foil was performed by gravure coating.

As the sealant film, a three-layer co-extruded non-stretched film of rPP layer/bPP layer/rPP layer made of polypropylene containing a lubricant was used. Use erucamide as a lubricant. The content of the lubricant was 1000 ppm for each layer.

Then, in order to improve the intensity|strength of the exterior material, such as the adhesive strength of an adhesive bond layer, the said aluminum foil wound up into roll shape was aged at 40 degreeC for 7 to 10 days.

Next, the aluminum foil was unwound and inspected over its entire length, and the aluminum foil without appearance defects such as indentation was rewound into a roll to produce an outer wrapping material roll. The width of the wrapping material roll is 240mm, and the winding length is 250m. Moreover, the thickness of the 1st adhesive bond layer of an exterior material was 4 micrometers, and the thickness of the 2nd adhesive bond layer was 2 micrometers.

According to the manufacturing method of the above-mentioned outer wrapping material roll, the surface of the inner surface is produced by using a plurality of sealant films having different surface properties on the inner surface or by changing the concave-convex shape of the surface of the second adhesive layer on the sealant film side. An outer wrapping material roll of a plurality of outer wrapping materials having different properties.

Next, three-dimensional surface texture parameters Spc, S5p, SRC, Safc, Sk, Sxp, Sdr, Sal, Vvc, and Vmc on the inner surface of the outer wrapping material of each outer wrapping material roll were measured. The specific measurement method applied at this time will be described later. And, using the values of these parameters, the F value was calculated according to the above formula 1.

Next, these wrapper rolls were stored at 40° C. for 2 days, and then the storage environment was changed to room temperature 25° C. and stored for 3 days.

Next, the outer wrapping material of each outer wrapping material roll is visually inspected over its entire length to check whether there is any appearance defect such as indentation on each outer wrapping material roll. The results are shown in Table 1 and Table 2.

【Table 1】

【Table 2】

The meanings of the symbols in the "defective appearance" column in the above table are as follows.

◯: The location where the appearance defect occurs is 0 (that is, the outer packaging material has no appearance defect).

×: There are one or more locations where the appearance defect occurs.

From Table 1 and Table 2, it can be seen that when the F value is greater than 0, that is, the outer packaging materials of Examples 1 to 20 have no appearance defects such as indentation. Therefore, when the F value is greater than 0, it is possible to suppress generation of blisters in the outer packaging material after molding the outer packaging material.

In addition, as can be seen from the "Spc" column of Table 1 and the "Spc" column of Table 2, when the Spc is in the range of -40mm ^-1 to -500mm ^-1 , the F value can be reliably made greater than 0. Therefore, for In order to reliably suppress appearance defects, the Spc is preferably in the range of -40 mm ^-1 to -500 mm ^-1 .

<<Measurement method of three-dimensional surface texture parameters>>

The method of measuring the value of the above-mentioned three-dimensional surface texture parameter is as follows.

The values of the three-dimensional surface texture parameters were measured by white light interference microscopy (vertical scanning low-coherence interferometry) based on ISO25178 for the measurement target area of a square of 1000 μm in length and 1000 μm in width on the inner surface of the packaging material.

The device used for this measurement is a scanning white light interference microscope "VS1330" (manufactured by Hitachi High-Tech Corporation), which has a surface spatial resolution of 350 nm and a vertical resolution of 0.01 nm.

Industrial availability

The present invention can be used for external packaging materials and electric storage devices such as lithium-ion secondary batteries (LIB), lithium-ion capacitors (LIC), electric double-layer capacitors (EDLC), and all-solid batteries.

This application claims the priority of Japanese Patent Application No. 2020-155255 filed on September 16, 2020, the disclosure content of which directly constitutes a part of the present application.

The terms and expressions used here are for illustration, not for limiting interpretation, and do not exclude any equivalent content of the characteristic items disclosed and described herein, and should be regarded as allowing various modifications within the scope of the claimed protection of the present invention.

Explanation of reference signs

1: Outer packing material

1a: Medial surface

1b: Outer surface

2: metal layer

3: Substrate layer

4: Sealant layer

5a, 5b: Adhesive layer

10: Outer packaging material roll

20: Outer packaging container

24: Battery main body (electric storage device main body)

25: Lithium ion secondary battery (storage equipment)

Claims (5)

1. An outer packaging material for an electrical storage device, comprising a base material layer as an outer layer, a sealant layer as an inner layer, and a metal layer as a barrier layer arranged between these two layers, The arithmetic mean curvature Spc (unit: mm ^-1 ) of the peak apex measured based on ISO25178, the height of the five-point peak area S5p (unit: μm), the smooth and rough cross SRC (unit: μm ^{2 )} in the inner surface of the outer packaging material ), regional typing complexity Safc (unit: dimensionless), core height difference Sk (unit: μm), pole height Sxp (unit: μm), root mean square slope Sdr (unit: %), minimum autocorrelation When the length Sal (unit: μm), the volume Vvc (unit: mL/m ² ) of the core space, and the volume Vmc (unit: mL/m ² ) of the core are respectively a to j, The value of F defined by the following formula 1 is greater than 0: F=-6.0-0.13a-0.51b+0.000073c-3.9d+0.91e+1.5f-3.9g+0.027h+2.1i+2.3j... (Formula 1). 2 . The outer packaging material for an electrical storage device according to claim 1 , wherein the arithmetic mean curvature Spc of the peak apex is in the range of -40 mm ^-1 to -500 mm ^-1 . 3. The exterior material for electrical storage devices according to claim 1 or 2, wherein the sealant layer is formed of a multilayer film containing polypropylene. 4. An electrical storage device, wherein the main body of the electrical storage device is packaged with the outer packaging material for an electrical storage device according to any one of claims 1 to 3. 5. A method for producing an outer packaging material for an electrical storage device, the outer packaging material for an electrical storage device comprising a base material layer as an outer layer, a sealant layer as an inner layer, and a barrier layer disposed between these two layers layer metal layer, The arithmetic mean curvature Spc (unit: mm ^-1 ) of the peak apex measured based on ISO25178, the height of the five-point peak area S5p (unit: μm), the smooth and rough cross SRC (unit: μm ^{2 )} in the inner surface of the outer packaging material ), regional typing complexity Safc (unit: dimensionless), core height difference Sk (unit: μm), pole height Sxp (unit: μm), root mean square slope Sdr (unit: %), minimum autocorrelation Length Sal (unit: μm), volume Vvc (unit: mL/m ² ) of the core space, and core volume Vmc (unit: mL/m ² ) as a~j respectively, Select an outer packaging material whose value of F defined by the following formula 1 is greater than 0 from a plurality of outer packaging materials, Aging of the selected outer packaging material in the rolled state: F=-6.0-0.13a-0.51b+0.000073c-3.9d+0.91e+1.5f-3.9g+0.027h+2.1i+2.3j... (Formula 1).

Images