TWI677129B - External storage material and power storage device for power storage device - Google Patents

Abstract

The present invention provides an exterior material 1 for a power storage device, which is characterized in that it includes a heat-resistant resin layer 2 as an outer layer, a thermoplastic resin layer 3 as an inner layer, and a metal foil disposed between the two layers. Layer 4; and the heat-resistant resin layer 2 has a vapor deposition layer on the outer layer; the vapor deposition layer is vapor-deposited from at least one vapor-deposition material selected from the group consisting of metal, metal oxide, and silicon dioxide. And the former. With this configuration, it is possible to provide an exterior material for a power storage device while ensuring good formability and preventing occurrence of bending (warping). The outer surface side of the vapor deposition layer 7 is preferably formed by laminating a protective resin layer 8. The protective resin layer 8 is selected from acrylic resin, fluorine resin, urethane resin, and polymer. Ester-based resin, epoxy-based resin and phenoxy-based resin are formed by one or more resins.

Description

Exterior material for power storage device and power storage device

The present invention relates to batteries or capacitors used in portable devices such as smart phones and tablet computers, and to power storage devices such as batteries or capacitors used in power storage of hybrid vehicles, electric vehicles, wind power, solar power, and night-time generators. Exterior material and power storage device exterior with the exterior material.

In recent years, with the reduction in thickness and weight of portable devices such as smart phones and tablet computer terminals, it has been used as a storage device for lithium-ion batteries, lithium polymer batteries, lithium-ion capacitors, and electric double-layer capacitors. As exterior materials, a laminated body formed of a heat-resistant resin layer / adhesive layer / metal foil layer / adhesive layer / thermoplastic resin layer is currently used to replace the conventional metal cans (see Patent Documents 1 and 2). Generally, the aforementioned laminated body is subjected to inflation molding or deep-extension molding to form a three-dimensional shape such as a substantially rectangular parallelepiped shape. In addition, for power sources such as electric vehicles, large power sources for storage purposes, capacitors, and the like, the laminated body (exterior material) having the above-mentioned configuration is used, and the number of exteriors is gradually increasing.

Among the above-mentioned exterior materials, the heat-resistant resin film used as the outer layer is generally made of polyamide from the viewpoint of ensuring good moldability when bulging or deep-drawing is performed. A resin film or a polyester resin film (see Patent Documents 1 and 2).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2011-98759

[Patent Document 2] Japanese Patent Laid-Open No. 2005-26152

However, since a polyamide resin film or a polyester resin film has high hygroscopicity, the exterior material using such a film as an outer layer has a problem of being easily bent (warped) due to moisture absorption and the like. In addition, when a polyamide resin film is used, bending is particularly likely to occur.

If the exterior material is bent in this way, when the exterior material sheet is formed, it will not be able to dress on the fixed position of the mold. In addition to the formation failure, the following problems are also prone to occur. After the inside of the battery case, when the peripheral edge portion of the case is to be heat-sealed, the sealing position is shifted, or the heat-sealed portion is wrinkled.

The present invention has been made in view of the above-mentioned technical background, and an object thereof is to provide an exterior material for a power storage device that can ensure good formability and prevent occurrence of bending (warping).

To achieve the foregoing object, the present invention provides the following means.

[1] An exterior material for a power storage device, comprising: a heat-resistant resin layer as an outer layer; a thermoplastic resin layer as an inner layer; and a metal foil layer disposed between the two layers; and The heat-resistant resin layer has a vapor deposition layer on the outer layer. The vapor deposition layer is formed by vaporizing at least one vapor deposition material selected from the group consisting of metal, metal oxide, and silicon dioxide.

[2] The exterior material for a power storage device according to the item 1, wherein a protective resin layer is laminated on an outer surface side of the vapor deposition layer; and the protective resin layer is selected from an acrylic resin, a fluorine resin, and an amine. One or two or more resins in the group consisting of urethane resin, polyester resin, epoxy resin, and phenoxy resin.

[3] A power storage device comprising: a power storage device main body and the exterior material for a power storage device described in the preceding paragraph 1 or 2; and the power storage device main body is covered by the exterior material Installer.

According to the invention of [1], a vapor deposition layer is laminated on the outer side of the heat-resistant resin layer in the exterior material, and the vapor deposition layer is at least one selected from the group consisting of a metal, a metal oxide, and a silicon dioxide. The presence of such a vapor deposition material can further suppress the intrusion of moisture from the outside by the presence of such a vapor deposition layer. Therefore, it is possible to prevent moisture from penetrating into the heat-resistant resin layer and to prevent moisture absorption of the heat-resistant resin layer, and to prevent the exterior material from being bent (to prevent warping from occurring). In addition, due to heat-resistant trees Since the vapor deposition layer is laminated on the outer side of the fat layer, the reduction in the strength of the heat-resistant resin layer can be suppressed, thereby further improving the moldability, and the puncture strength can be further improved.

According to the invention of [2], since the specific protective resin layer is further laminated on the outer surface side of the vapor deposition layer, the separation and peeling of the vapor deposition layer can be sufficiently prevented, and the effect of suppressing the intrusion of moisture from the outside can be achieved. Long time. In addition, by laminating such a protective resin layer, processing can be performed more easily when the device is manufactured (processability can be improved). In addition, due to the above-mentioned specific resins (one or two selected from the group consisting of acrylic resins, fluorine resins, urethane resins, polyester resins, epoxy resins, and phenoxy resins) The above resins) have excellent chemical resistance. Therefore, by disposing the protective resin layer on the outer side, the electrolyte resistance can be improved (for example, there is no obstacle when the electrolyte adheres to the outer surface of the exterior material).

According to the invention of [3], it is possible to provide a high-quality power storage device that is mounted on an exterior material that is hard to bend.

1‧‧‧ Exterior materials for power storage devices

2‧‧‧ heat-resistant resin layer (outer layer)

3‧‧‧ thermoplastic resin layer (inner layer)

4‧‧‧ metal foil layer

5‧‧‧The first adhesive layer

6‧‧‧The second adhesive layer

7‧‧‧Steamed layer

8‧‧‧ protective resin layer

11‧‧‧Shape

19‧‧‧ Power storage device body

20‧‧‧ Power storage device

FIG. 1 is a sectional view showing an embodiment of an exterior material for a power storage device according to the present invention.

Fig. 2 is a cross-sectional view showing another embodiment of an exterior material for a power storage device according to the present invention.

FIG. 3 is a cross-sectional view showing an embodiment of a power storage device using an exterior material for a power storage device according to the present invention.

[Fig. 4] An explanatory diagram of the evaluation method for preventing bending resistance, (A) is an oblique view of the state immediately after the incision is placed on the evaluation sample; (B) is an oblique view of the state where the evaluation sample is bent; Sectional view of line XX in (B).

An embodiment of an exterior material 1 for a power storage device according to the present invention is shown in FIG. 1. This exterior material 1 for a power storage device is used as a lithium ion secondary battery case by a user. The exterior material 1 for a power storage device is used as a case of a secondary battery by performing, for example, deep drawing forming, inflation forming, and the like.

The exterior material 1 for a power storage device is integrated with a heat-resistant resin layer (outer layer) 2 through a surface 4a on one side of the metal foil layer 4 through a first adhesive layer 5. The other surface 4 b is integrated with the thermoplastic resin layer (inner layer) 3 by a second adhesive layer 6, and a vapor deposition layer 7 is laminated on the outer surface of the heat-resistant resin layer 2. In this embodiment, a protective resin layer 8 is laminated on the outer surface of the vapor deposition layer 7 (see FIG. 1).

In the present invention, the vapor deposition layer 7 is a laminated layer on the outer surface side of the heat-resistant resin layer 2. The vapor deposition layer 7 is formed by vapor deposition of at least one vapor deposition material selected from the group consisting of metal, metal oxide, and silicon dioxide. The vapor deposition material may be vapor-deposited on the outer surface side of the heat-resistant resin layer 2 during the manufacturing process, or may be vapor-deposited on the inner surface of the protective resin layer 8. The target surface may be vaporized, and a corona treatment, a coating treatment, etc. may be applied in advance. The means for vaporizing is not particularly limited, but examples thereof include a chemical vaporization method (CVD method), a physical vaporization method (DVD method), and the like.

The metal is not particularly limited, but examples thereof include aluminum, chromium, gold, silver, copper, platinum, and nickel. The metal oxide is not particularly limited, and examples thereof include alumina and the like.

The vapor deposition layer 7 may be composed of two or more vapor deposition layers. Examples Such as: the structure of two layers of silicon dioxide vapor deposition layer / alumina vapor deposition layer.

The thickness of the aforementioned vapor deposition layer 7 is preferably set to 50 Å to 10,000 Å. 50 Å or more can sufficiently prevent moisture absorption of the heat-resistant resin layer 2, and 10,000 Å or less can promote cost reduction and sufficiently ensure the flexibility of the exterior material. Among them, the thickness of the aforementioned vapor deposition layer 7 is particularly preferably set at 200Å to 2000Å.

In the present invention, it is preferable to adopt a configuration in which a protective resin layer 8 is further laminated on the outer surface side of the vapor deposition layer 7. The protective resin layer 8 is one or two selected from the group consisting of an acrylic resin, a fluorine resin, a urethane resin, a polyester resin, an epoxy resin, and a phenoxy resin. The above resins are preferably formed. The protective resin layer 8 is particularly preferably formed of a fluorine-based resin, a urethane-based resin, a phenoxy-based resin, or a mixed resin of a urethane-based resin and a phenoxy-based resin.

The thickness of the protective resin layer 8 is preferably set to 0.5 μm to 5 μm. A thickness of 0.5 μm or more can sufficiently prevent peeling, peeling, and injury of the vapor deposition layer, and a thickness of 5 μm or less can sufficiently ensure the lightweight of the exterior material and the energy density of the power storage device.

The heat-resistant resin constituting the heat-resistant resin layer (outer layer) 2 is a heat-resistant resin that does not melt due to the heat-sealing temperature when a heat-sealed exterior material is used. The heat-resistant resin is preferably a heat-resistant resin having a melting point that is higher than the melting point of the thermoplastic resin constituting the thermoplastic resin layer 3 by 10 ° C or higher, and has a melting point that is higher than the melting point of the thermoplastic resin by 20 ° C or higher. The heat-resistant resin is particularly preferable.

The heat-resistant resin layer (outer layer) 2 is not particularly limited, but examples thereof include a polyamide film such as a nylon film, a polyester film, and the like, and these stretched films can be preferably used. The heat-resistant resin layer 2 is a biaxially stretched biaxially stretched nylon film or the like. Polyethylene terephthalate film, biaxially stretched polybutylene terephthalate (PBT) film, biaxially stretched polyethylene terephthalate (PET) film, or biaxially stretched polyethylene naphthalate (PEN) The film is particularly good. The nylon film is not particularly limited, but examples thereof include 6 nylon films, 6,6 nylon films, and MXD nylon films. The heat-resistant resin layer 2 may be formed of a single layer, or may be formed of, for example, a plurality of layers made of a polyester film / polyamide film (a plurality of layers made of a PET film / nylon film, etc.).

The thickness of the heat-resistant resin layer 2 is preferably 5 μm to 50 μm. When a polyester film is used, the thickness is preferably 5 μm to 50 μm, and when a nylon film is used, the thickness is preferably 12 μm to 50 μm. By setting above the above-mentioned preferred lower limit value, sufficient strength of the packaging material can be ensured, and by setting below the above-mentioned preferred upper limit value, the stress during inflation molding and deep-extension molding can be reduced and improved Formability.

The thermoplastic resin layer (inner layer) 3 has excellent chemical resistance even for corrosive electrolytes used in lithium ion batteries and the like, and is responsible for imparting heat sealing properties to packaging materials.

The thermoplastic resin layer 3 is not particularly limited, but is preferably a thermoplastic resin unstretched film layer. The thermoplastic resin unstretched film layer 3 is not particularly limited, but is selected from the group consisting of polyethylene, polypropylene, and olefinic copolymers, and at least one type of acid-modified products and ionic polymers. A non-stretched film made of a plastic resin is preferred.

The thickness of the thermoplastic resin layer 3 is preferably set to 20 μm to 80 μm. By setting it at 20 μm or more, it is possible to sufficiently prevent the occurrence of pinholes. At the same time, by setting it at 80 μm or less, the amount of resin can be reduced and the cost can be reduced. The thickness of the thermoplastic resin layer 3 is particularly preferably set to 30 μm to 50 μm. The thermoplastic resin Layer 3 may be a single layer or a plurality of layers.

The metal foil layer 4 is responsible for providing the outer packaging material 1 with gas barrier properties to prevent oxygen or moisture from entering. The metal foil layer 4 is not particularly limited, and examples thereof include aluminum foil, copper foil, and SUS (stainless steel) foil. Generally, aluminum foil and SUS foil are used. As the material of the aluminum foil, O material of A8079 and O material of A8021 are preferable. The thickness of the metal foil layer 4 is preferably 15 μm to 80 μm. When the thickness is 15 μm or more, pinholes can be prevented from being generated when the metal foil is manufactured. At the same time, when the thickness is 80 μm or less, the stress during bulging and deep extension molding can be reduced to improve formability.

It is preferable that the metal foil layer 4 is chemically treated at least on the inner surface 4b (the surface on the second adhesive layer 6 side). The chemical conversion treatment as described above can sufficiently prevent the surface of the metal foil from being corroded by the contents (the electrolyte of the battery, etc.). For example, a metal foil can be formed by performing the following processing. That is, for example, the surface of the metal foil after being subjected to the degreasing treatment may be subjected to a chemical conversion treatment by applying an aqueous solution of any one of the following 1) to 3) and drying it.

1) An aqueous solution containing a mixture of at least one compound selected from the group consisting of phosphoric acid, chromic acid, metal salts of fluoride, and non-metal salts of fluoride.

2) A resin containing at least one selected from the group consisting of phosphoric acid, acrylic resin, Chitosan derivative resins, and phenol resin, and a group selected from chromic acid and chromium (III) salt An aqueous solution of a mixture of at least one compound

3) A resin containing at least one member selected from the group consisting of phosphoric acid, an acrylic resin, a chitosan derivative resin, and a phenol-based resin, and at least one member selected from the group consisting of chromic acid and a chromium (III) salt. An aqueous solution of a compound and a mixture of at least one compound selected from the group consisting of a metal salt of a fluoride and a non-metal salt of a fluoride

In the aforementioned chemical conversion film, the chromium adhesion amount (on each side) is preferably 0.1 mg / m ² to 50 mg / m ² , and 2 mg / m ² to 20 mg / m ² is particularly preferred.

The first adhesive layer 5 is not particularly limited, but examples thereof include a polyurethane adhesive layer, a polyester polyurethane adhesive layer, and a polyether polyurethane adhesive layer. The thickness of the first adhesive layer 5 is preferably set to 1 μm to 5 μm. Among them, from the viewpoint of thinning and reducing the weight of the exterior material, the thickness of the first adhesive layer 5 is particularly preferably set to 1 μm to 3 μm.

Although the second adhesive layer 6 is not particularly limited, for example, the first adhesive layer 5 described above can be used, but a polyolefin-based adhesive having less swelling due to the electrolytic solution is preferably used. The thickness of the second adhesive layer 6 is preferably set to 1 μm to 5 μm. Among them, from the viewpoint of thinning and lightening the exterior material, the thickness of the second adhesive layer 6 is particularly preferably set to 1 μm to 3 μm.

The exterior material 1 of the present invention can be formed into a case (battery case, etc.) by forming (deep drawing, inflation, etc.). In addition, the exterior material 1 of the present invention may be used without being formed.

One of the battery devices 20 constructed using the exterior material 1 of the present invention The pattern is shown in Figure 3. This storage battery device 20 is a lithium ion secondary battery.

The battery 20 includes an electrolyte 21, a tab 22, and the outer casing 1 having a flat shape without being formed, and a molded case 11 having a receiving recess 11b obtained by forming the outer casing 1 (see FIG. 3). ). The power storage device body 19 is configured by the electrolyte 21, the tab 22, and the like.

A part of the electrolyte 21 and the tab 22 are received in the receiving recess 11b of the molded case 11, and the planar exterior material 1 is disposed on the molded case 11. The peripheral edge portion of the exterior material 1 ( The inner layer 3) of the molded case 11 is joined to and sealed with the sealing peripheral portion 11a (the inner layer 3) of the molded case 11 to form the battery 20 described above. In addition, the tip end portion of the tab 22 is led out to the outside (see FIG. 3).

In the above embodiment, the protective resin layer 8 is laminated on the outer side of the vapor deposition layer 7, but it is not particularly limited to this configuration. For example, as shown in FIG. 2, no protective resin is provided. The structure of the layer 8 (the structure in which the vapor deposition layer 7 is exposed) or a structure in which the protective resin layer 8 is laminated on the outer surface side of the vapor deposition layer 7 is replaced with another layer body.

[Example]

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

<Example 1>

Physical evaporation method by heating electron beam on one side of a biaxially stretched polyethylene terephthalate (PET) film (melting point: 230 ° C) 2 having a thickness of 25 μm The silicon dioxide was vaporized to form a vaporized layer 7 having a thickness of 1000Å.

On the other hand, on both sides of the aluminum foil 4 having a thickness of 35 μm, a chemical conversion treatment solution made of phosphoric acid, polyacrylic acid, trivalent chromium compound, water, and alcohol was applied and dried at 180 ° C. to form a chemical conversion film. The amount of chromium deposited on the formed film was 10 mg / m ^{2 on} one side.

Next, on the surface 4a on one side of the aluminum foil 4 that has undergone the aforementioned chemical conversion treatment, a two-liquid curable urethane-based adhesive (first adhesive layer) 5 and the aforementioned vapor deposition layer 7bis are passed through The shaft-stretched PET film 2 is dry-laminated (bonded). At this time, the non-evaporated surface of the biaxially stretched PET film is in contact with the urethane-based adhesive 5 and laminated.

Next, the adhesive solution was applied to the other surface 4b of the aluminum foil 4 using a gravure roller, and then dried with hot air at 80 ° C. to form a bonding resin layer (second adhesive layer) 6 having a thickness of 3 μm. The adhesive solution is a mixed solvent (toluene / methyl ethyl ketone = 8 parts by mass / 2 parts by mass of mixed solvent) in which 85 parts by mass of maleic acid-denatured polypropylene (a copolymer of propylene and ethylene and maleic anhydride) is dissolved Graft polymerization was performed to form a denatured polypropylene resin; the dissolution temperature was 80 ° C.) 15 parts by mass, and 0.9 parts by mass of the polymer of hexamethylene diisocyanate was mixed to form an adhesive solution.

Next, by laminating the surface of the resin layer 6 formed on the surface 4b on the other side of the aluminum foil 4, the melting point was 140 ° C, the MFR (melt flow rate) was 4.5 g / 10 minutes, and A propylene-ethylene random copolymer film (inner layer; sealing layer) 3 having a thickness of 40 μm can be used to obtain an exterior material 1 for a power storage device configured as shown in FIG. 2.

<Example 2>

In addition to the use of biaxially stretched PET films with a thickness of 12 μm (melting point 230 ℃) / 15 μm biaxially stretched polyamide film (melting point 220 ° C 6 nylon film) 2-layer laminated film (Polyamide film is placed on the outside and a vapor deposition layer is placed on the surface area of the polyamide film) A biaxially stretched PET film with a thickness of 25 μm was formed by the physical evaporation method of resistance heating to form an aluminum vapor deposition layer with a thickness of 600 Å instead of a silicon dioxide vapor deposition layer with a thickness of 1000 Å. The rest were the same as in Example 1, and were obtained as An exterior material 1 for a power storage device having a configuration shown in FIG. 2.

<Example 3>

Except the use of a biaxially-stretched polyimide film with a thickness of 25 μm (6 nylon film with a melting point of 220 ° C.) instead of the two-layer laminated film, it was the same as in Example 2 to obtain an exterior for a power storage device having the structure shown in FIG.材 1。 Material 1.

<Example 4>

Except for the physical vapor deposition method of electron beam heating, a silicon dioxide-alumina vapor deposition layer having a thickness of 1500 Å (a vapor deposition layer obtained by vaporizing a mixture of silicon dioxide and alumina) is used instead of a silicon dioxide vapor deposition layer having a thickness of 1000 Å. Others are the same as in Example 1, and an exterior material 1 for a power storage device having the structure shown in FIG. 2 is obtained.

<Example 5>

Except the use of a biaxially stretched polyamide film with a thickness of 25 μm (6 nylon film with a melting point of 220 ° C.) instead of a biaxially stretched PET film with a thickness of 25 μm, it was the same as in Example 1 to obtain a power storage device having the structure shown in FIG. 2.装 用 装 装 材料 1。 Exterior materials 1 for the device.

<Example 6>

In addition to the vapor deposition layer 7 laminated on the outer surface of the biaxially stretched polyamide film 2, a protective resin layer 8 made of a urethane resin with a thickness of 2 μm is further laminated to Except that, the other parts were the same as those in Example 5, and an exterior material 1 for a power storage device having a structure shown in FIG. 1 was obtained. The protective resin layer laminated on the outer surface of the vapor deposition layer was dried by hot air drying at 80 ° C after coating with a gravure roll.

<Example 7>

In addition to the aluminum vapor deposition layer 7 laminated on the outer surface of the biaxially-stretched polyamide film 2, a protective resin layer 8 made of a mixed resin of a urethane resin and a phenoxy resin is further laminated to a thickness of 2 μm. Others are the same as in Example 3, and an exterior material 1 for a power storage device having the structure shown in FIG. 1 is obtained. The protective resin layer laminated on the outer surface of the vapor deposition layer was dried by hot air drying at 80 ° C after coating with a gravure roll.

<Example 8>

Except that the thickness of the silicon dioxide vapor deposition layer was set to 2000 Å instead of 1000 Å, and a protective resin layer 8 made of acrylic resin with a thickness of 2 μm was further laminated on the outer surface of the silicon dioxide vapor deposition layer 7. Similarly, an exterior material 1 for a power storage device configured as shown in FIG. 1 was obtained. The protective resin layer was deposited on the outer area of the vapor deposition layer, followed by coating with a gravure roll and drying with hot air at 80 ° C.

<Example 9>

Except that the aluminum vapor deposition layer 7 laminated on the outer surface of the biaxially stretched polyamide film 2 was further laminated with a protective resin layer 8 made of epoxy resin and having a thickness of 2 μm, the rest were the same as in Example 3 to obtain An exterior material 1 for a power storage device configured as shown in FIG. 1. The protective resin layer laminated on the outer surface of the vapor deposition layer was dried by hot air drying at 80 ° C after coating with a gravure roll.

<Example 10>

A protective resin layer 8 made of a polyester resin with a thickness of 2 μm was further laminated on the outer surface of the aluminum vapor deposition layer 7 laminated on the outer surface of the biaxially stretched polyamide film 2. An exterior material 1 for a power storage device configured as shown in FIG. 1. The protective resin layer laminated on the outer surface of the vapor deposition layer was dried by hot air drying at 80 ° C after coating with a gravure roll.

<Example 11>

Except that the aluminum vapor deposition layer 7 laminated on the outer surface of the biaxially-stretched polyamide film 2 was further laminated with a protective resin layer 8 made of a fluororesin to a thickness of 2 μm, the rest were the same as in Example 3, and obtained as follows An exterior material 1 for a power storage device having the configuration shown in FIG. 1. The protective resin layer laminated on the outer surface of the vapor deposition layer was dried by hot air drying at 80 ° C after coating with a gravure roll.

<Comparative example 1>

Except that the structure without a silicon dioxide vapor deposition layer was the same as in Example 1, an exterior material for a power storage device was obtained.

<Comparative example 2>

Except that the aluminum vapor deposition layer was not provided, it was the same as in Example 3, and an exterior material for a power storage device was obtained.

<Comparative example 3>

Except for the dry lamination of the biaxially stretched polyamide film with the side of one side of the aluminum foil that has undergone the chemical conversion treatment, the vapor deposition surface (aluminum vapor deposition layer 7) of the biaxially stretched polyamide film 2 is made to have an amine group. Except that the ethyl formate-based adhesive 5 was laminated in contact, it was the same as in Example 3, and an exterior material for a power storage device was obtained.

With respect to each of the obtained exterior materials for power storage devices, performance evaluation was performed using the following evaluation method as a reference. The results are shown in Table 1.

<Formability Evaluation Method>

Use an inflation molding machine (No. TP-25C-X2) manufactured by Amada Co., Ltd. to perform an inflation molding of a slightly cuboid shape with a length of 55 mm and a width of 35 mm for the exterior material. Whether or not there are pinholes and cracks in the corners of the obtained formed body, thereby measuring the "maximum forming depth (mm)" in which such pinholes and cracks do not occur. A maximum forming depth of 7.0 mm or more is "○"; a maximum forming depth of 6.0 mm or more and less than 7.0 mm is "△"; a maximum forming depth of less than 6.0 mm is "×".

<Electrolytic Resistance Evaluation Method>

The outer packaging material was cut into a test piece with a width of 15 mm, and the lithium hexafluorophosphate was dissolved in a mixed solvent prepared by mixing ethylene carbonate and diethyl carbonate in a volume ratio of 1: 1 to obtain a concentration of 1 mole / The solution of L was put in a tetrafluoroethylene resin jar and stored in an 85 ° C oven for one week. After taking out the test piece, the aluminum foil 4 and the ethylene-propylene random copolymer resin layer (inner layer) 3 were peeled off. Interface, the lamination strength (adhesion strength) between the two (N / 15mm width) was measured. Then, the strength of 10 (N / 15mm width) or more is "○"; the strength of 5 (N / 15mm width) or more is less than 10 (N / 15mm width) is "△"; Wide) is "×".

<Bend prevention evaluation method>

The exterior material is cut into a 100 mm × 100 mm square shape, and as shown in FIG. 4 (A), a cut that crosses at the center point (center of gravity) and penetrates vertically along the diagonal of the square (one cut 31 length 40mm, the length of the other cut 31 is 40mm) In a room at a relative humidity of 75% and a temperature of 23 ° C., the vapor deposition layer 7 or the protective resin layer 8 of the sample was set as the lower side, and the inner layer 3 was placed on the water platform as the upper side. After maintaining this state for 1 hour, the height (warpage amount) H from the upper surface of the water platform to the highest part (central point) of the sample was measured (see FIG. 4 (C)). Those with a height of less than 10mm are "○"; those with a height of more than 10mm and less than 15mm are "△"; those with a height of more than 15mm are "x".

It is clear from Table 1 that the exterior materials for power storage devices according to Examples 1 to 11 of the present invention have a large maximum forming depth, and can ensure excellent moldability even with deep forming, and have excellent electrolyte resistance. Furthermore, it has excellent bending resistance.

On the other hand, the exterior materials of Comparative Examples 1 to 3 had poor bending prevention properties and caused great warpage.

[Possibility of industrial use]

Specific examples of the exterior material for a power storage device according to the present invention may be, for example ,:

． Power storage devices such as lithium secondary batteries (lithium ion batteries, lithium polymer batteries, etc.)

． Lithium ion capacitor

． Electric double layer capacitor

Used as exterior materials for various power storage devices.

This application claims priority from Japanese Patent Application No. 2014-255885, filed on Dec. 18, 2014, and its disclosure directly constitutes a part of this application.

The terms and descriptions used herein are for explaining the embodiments of the present invention. Use, but the invention is not limited to this. Any equivalents of the characteristic matters disclosed and described in the present invention should not be excluded, and various modifications within the scope claimed by the present invention should also be understood as acceptable.

Claims (8)

An exterior material for a power storage device, comprising: a heat-resistant resin layer as an outer layer; a thermoplastic resin layer as an inner layer; and a metal foil layer disposed between the two layers; and the heat-resistant resin. The vapor deposition layer is formed on the outer layer side of the layer; the protective resin layer is formed on the outer surface side of the vapor deposition layer; and the vapor deposition layer is at least one selected from the group consisting of metal, metal oxide, and silicon dioxide. Steamed material formed by steaming. The exterior material for a power storage device according to item 1 of the patent application scope, wherein the protective resin layer is selected from the group consisting of acrylic resin, fluorine resin, urethane resin, polyester resin, and epoxy resin. Based on one or two or more resins in the group of resins and phenoxy resins. The exterior material for a power storage device according to item 1 or 2 of the scope of the patent application, wherein the thickness of the vapor deposition layer is 50 Å to 10,000 Å. The exterior material for a power storage device according to item 1 or 2 of the scope of patent application, wherein the thickness of the vapor deposition layer is 200 Å to 2000 Å. The exterior material for a power storage device according to item 1 or 2 of the scope of the patent application, wherein the thickness of the protective resin layer is 0.5 μm to 5 μm. The exterior material for a power storage device according to item 3 of the scope of patent application, wherein the thickness of the protective resin layer is 0.5 μm to 5 μm. The exterior material for a power storage device according to item 4 of the scope of patent application, wherein the thickness of the protective resin layer is 0.5 μm to 5 μm. A power storage device is characterized in that the power storage device includes a power storage device main body and an exterior material for a power storage device as described in any one of claims 1 to 7; and the power storage device main body is formed by the external Outfitting materials.