JP6788991B2 - Exterior material for power storage device and power storage device - Google Patents

Description

The present invention relates to batteries and capacitors used in portable devices such as smartphones and tablets, storage devices such as batteries and capacitors used for storing hybrid vehicles, electric vehicles, wind power generation, solar power generation, and nighttime electricity, and storage devices such as capacitors. The present invention relates to an exterior material for such a power storage device.

In recent years, as mobile devices such as smartphones and tablet terminals have become thinner and lighter, the exterior materials of lithium ion secondary batteries and lithium polymer secondary batteries mounted on them have been replaced with metals instead of conventional metal cans. A laminated exterior material in which resin films are bonded to both sides of the foil is used. Similarly, it is being considered to mount a capacitor, a capacitor, or the like using a laminated exterior material on an IC card or an electronic device as a backup power source.

Assuming that the battery body is housed in a laminated exterior material in which resin films are laminated on both sides of a metal foil, for example, a positive electrode, a separator, a negative electrode, and a negative electrode laminated in a sealed exterior material made of a flexible film, and A card battery containing a battery constituent substance made of an electrolyte, wherein a laminated film having a structure in which a thermoplastic resin, a metal foil, and a thermoplastic resin are sequentially laminated as the exterior material is known. (See Patent Document 1).

Japanese Unexamined Patent Publication No. 2005-56854

However, in the battery described in Patent Document 1, since it is necessary to provide a tab lead wire (lead wire) led out from the electrode, there is a problem that the number of parts increases accordingly. Further, since this tab lead wire needs to be fixed at the heat-sealed portion on the periphery of the laminated exterior material, there is a problem that the man-hours at the time of manufacturing increase and it takes time and effort.

Further, since the exterior material having the above-mentioned conventional structure cannot sufficiently prevent corrosion of the barrier layer due to the electrolytic solution, it has been desired to further improve the corrosion resistance of the exterior material.

The present invention has been made in view of such a technical background, and is a power storage device capable of energizing without requiring tab lead, having sufficient corrosion resistance of the exterior material, and having sufficient interlayer bonding force. An object of the present invention is to provide an exterior material for a power storage device.

In order to achieve the above object, the present invention provides the following means.

[1] Corrosion-resistant layer / base layer / inner adhesive layer / thermoplastic resin layer are laminated in this order on one surface of the metal foil layer, and the inner adhesive layer and the heat are formed on a part of the surface of the base layer. An exterior material for a power storage device provided with a conductive portion that is not coated with a plastic resin layer.
The corrosion-resistant layer is a layer made of a metal oxide or a Si oxide.
An exterior material for a power storage device, wherein the base layer is a layer containing one or more components selected from the group consisting of metal and Si, and a water-soluble resin.

[2] Corrosion-resistant layer / intermediate layer / base layer / inner adhesive layer / thermoplastic resin layer are laminated in this order on one surface of the metal foil layer, and the inner adhesive layer is formed on a part of the surface of the base layer. And an exterior material for a power storage device provided with a conductive portion that is not coated with the thermoplastic resin layer.
The corrosion-resistant layer is a layer made of a metal oxide or a Si oxide.
The intermediate layer is a layer containing a hydrolyzate of metal alkoxide or a hydrolyzate of Si alkoxide.
An exterior material for a power storage device, wherein the base layer is a layer containing one or more components selected from the group consisting of metal and Si, and a water-soluble resin.

[3] The exterior material for a power storage device according to item 2 above, wherein the metal in the metal alkoxide is at least one metal selected from the group consisting of Cr, Zr, Ti, Ce and Al.

[4] When the organic matter content in the corrosion-resistant layer is "X", the organic matter content in the intermediate layer is "Y", and the organic matter content in the underlayer is "Z".
X <Y <Z
The exterior material for a power storage device according to the above item 2 or 3, which is related to the above.

[5] The exterior material for a power storage device according to any one of the above items 1 to 4, wherein the corrosion-resistant layer has an organic substance content of less than 50% by mass, and the underlying layer has an organic substance content of 50% by mass or more.

[6] The exterior material for a power storage device according to any one of items 1 to 5 above, wherein the metal foil layer is made of copper foil or iron foil.

[7] Item 1 to 5 above, wherein the metal foil layer is formed of a metal foil having a plating layer made of at least one metal selected from the group consisting of Ni, Cr, Zn and Sn formed on at least one surface of the metal foil. The exterior material for a power storage device according to any one of the items.

[8] A heat-resistant resin layer is laminated on the other surface of the metal foil layer, and a terminal portion not covered with the heat-resistant resin layer is provided on a part of the other surface of the metal foil layer. The exterior material for a power storage device according to any one of the preceding items 1 to 7.

[9] The two exterior materials for the power storage device according to any one of the above items 1 to 8 and
With the device body
The device main body is housed in a space between the two exterior materials arranged so that the thermoplastic resin layers face each other, and the electrodes of the device main body and the conductive part of the exterior material are connected to each other. , A power storage device characterized in that the thermoplastic resin layers at the peripheral edges of the two exterior materials are joined and sealed.

In the invention of [1], since the conductive portion connecting the device main body portion is formed as a part of the exterior material, energization is possible without using a tab lead. By eliminating the tab lead, it is possible to contribute to weight reduction and miniaturization of the power storage device. Since the corrosion-resistant layer / base layer / inner adhesive layer / thermoplastic resin layer are laminated in this order on one surface of the metal foil layer, and the corrosion-resistant layer is a layer made of a metal oxide or a Si oxide. The corrosion resistance of the metal foil can be improved, and the base layer is a layer containing one or more components selected from the group consisting of metal and Si, and a water-soluble resin, so that it is adhered inside. It can be stably adhered to the agent layer. Therefore, it is possible to provide an exterior material for a power storage device, which is excellent in corrosion resistance of a metal foil, excellent in electrolytic solution resistance, and the like, and has sufficient adhesive strength.

In the invention of [2], since the conductive portion connecting the device main body portion is formed as a part of the exterior material, energization is possible without using a tab lead. By eliminating the tab lead, it is possible to contribute to weight reduction and miniaturization of the power storage device. Corrosion-resistant layer / intermediate layer / base layer / inner adhesive layer / thermoplastic resin layer are laminated in this order on one surface of the metal foil layer, and the corrosion-resistant layer is a layer made of metal oxide or Si oxide. Therefore, the corrosion resistance of the metal foil can be improved, and the base layer is a layer containing one or more components selected from the group consisting of metal and Si, and a water-soluble resin. , Can be stably adhered to the inner adhesive layer. Further, since the base layer is laminated on the corrosion resistant layer via an intermediate layer (a layer containing a hydrolyzate of metal alkoxide or a hydrolyzate of Si alkoxide), more sufficient adhesive strength can be obtained, and the metal foil can be obtained. The layer and the thermoplastic resin layer are joined with sufficient adhesive force. Therefore, it is possible to provide an exterior material for a power storage device, which is excellent in corrosion resistance of a metal foil, excellent in electrolytic solution resistance, and the like, and has a more sufficient adhesive force.

In the invention of [3], since the metal constituting the metal alkoxide in the intermediate layer is at least one metal selected from the group consisting of Cr, Zr, Ti, Ce and Al, the corrosion resistant layer is interposed via the intermediate layer. The base layer is joined with a more sufficient adhesive force, and the metal foil layer and the thermoplastic resin layer are joined with a more sufficient adhesive force.

In the invention of [4], since the configuration has a relationship of X <Y <Z, the adhesive force between the layers can be further enhanced.

In the invention of [5], since the organic matter content in the corrosion-resistant layer is less than 50% by mass, the bonding force between the metal foil layer and the corrosion-resistant layer can be further improved, and the organic matter content in the base layer is 50% by mass. As described above, the bonding strength between the base layer and the inner adhesive layer can be further improved, and the exterior material for a power storage device in which the metal foil layer and the thermoplastic resin layer are bonded with a more sufficient adhesive force is provided. Will be done.

In the invention of [6], the metal foil layer is composed of copper foil or iron foil, and when it is copper foil, the heat dissipation of the device can be improved, and when it is iron foil, the exterior The strength of the material can be improved.

In the invention of [7], the metal foil layer is composed of a metal foil having a plating layer made of at least one metal selected from the group consisting of Ni, Cr, Zn and Sn formed on at least one surface of the metal foil. Therefore, the corrosion resistance can be improved.

In the invention of [8], since the heat-resistant resin layer is laminated on the other surface of the metal foil layer, sufficient insulation (excluding the terminal portion) can be ensured, and physical strength and impact resistance are also obtained. In addition to being able to secure it, an exposed portion (terminal portion) that is not covered with the heat-resistant resin layer is provided on a part of the other surface of the metal foil layer, so that electricity is supplied through this exposed portion (terminal portion). It can be carried out.

In the invention (storage device) of [9], since it is configured by using any of the exterior materials [1] to [8] above, it is possible to energize without using a tab lead, and the weight is reduced and the size is reduced. Provided is a highly durable power storage device that is covered with an exterior material that has excellent corrosion resistance, excellent electrolytic solution resistance, and sufficient adhesive strength. ..

It is sectional drawing which shows one Embodiment of the exterior material for a power storage device which concerns on this invention. It is sectional drawing which shows an example of the power storage device configured by using the exterior material for power storage device of FIG. It is a top view of the power storage device of FIG.

An embodiment of the power storage device 1 according to the present invention is shown in FIGS. The power storage device 1 is a laminated exterior battery, and includes a bare cell 60 as a device main body and an exterior case 45 for accommodating the bare cell 60.

As shown in FIGS. 2 and 3, the outer case 45 has a main body 51 having a concave portion 52 having a plan view angle and a flange 53 extending outward from the opening edge of the concave portion 52, and an outer peripheral dimension of the flange 53 of the main body 51. It was manufactured in combination with a lid (bottom lid) 55 of the same size. The recess 52 forms a storage space for the bare cell 60.

The constituent materials of the main body 51 include a second metal foil layer 12, a second thermoplastic resin layer 14 laminated on one surface (first surface) side of the second metal foil layer 12, and the first. An exterior material (exterior material for power storage device) 50 having a second heat-resistant resin layer 18 laminated on the other surface (second surface) side of the two metal layers 12 is used (see FIG. 2). ).

As the constituent materials of the lid 55, the first metal foil layer 2, the first thermoplastic resin layer 4 laminated on one surface (first surface) side of the first metal foil layer 2, and the above. An exterior material (exterior material for power storage device) 50 having a first heat-resistant resin layer 8 laminated on the other surface (second surface) side of the first metal foil layer 2 is used (FIG. 2).

Explaining the structure of the exterior material 50 constituting the main body 51 in detail, as shown in FIG. 1, on one surface of the second metal foil layer 12, the corrosion resistant layer 81 / intermediate layer 82 / base layer 83 / The inner adhesive layer 84 / second thermoplastic resin layer 14 are laminated in this order, and the inner adhesive layer 84 and the second thermoplastic are formed on a part of the surface (central portion in the present embodiment) of the base layer 83. A negative electrode conductive portion 54 not covered with the resin layer 14 is provided, and an inner adhesive layer is provided on the surface of the base layer 83 (the surface on the side of the second thermoplastic resin layer 14) excluding the negative electrode conductive portion 54. The second thermoplastic resin layer 14 is laminated via 84. Further, the second heat-resistant resin layer 18 is laminated on the other surface of the second metal foil layer 12 via the outer adhesive layer 90, and a part of the other surface of the second metal foil layer 12 (the present). In the embodiment, the central portion) is provided with the negative electrode terminal portion 19 not covered with the second heat-resistant resin layer 18 and the outer adhesive layer 90 (see FIG. 1). The corrosion-resistant layer 81 is a layer made of a metal oxide or a Si oxide, the intermediate layer 82 is a layer containing a hydrolyzate of a metal alkoxide or a hydrolyzate of a Si alkoxide, and the base layer 83 is a layer. , A layer containing one or more components selected from the group consisting of metal and Si, and a water-soluble resin. Details of the configurations of the corrosion-resistant layer 81, the intermediate layer 82, and the base layer 83 will be described later. In FIGS. 1 and 2, 80 is a functional layer, and the functional layer is a corrosion resistant layer 81 / intermediate layer 82 / base layer in order from the second metal foil layer 12 side to the second thermoplastic resin layer 14 side. It is composed of 83 / inner adhesive layer 84.

Explaining the structure of the exterior material 50 constituting the lid 55 in detail, as shown in FIG. 1, one surface of the first metal foil layer 2 has a corrosion resistant layer 81 / intermediate layer 82 / base layer 83. / The inner adhesive layer 84 / the first thermoplastic resin layer 4 is laminated in this order, and the inner adhesive layer 84 and the first heat are applied to a part of the surface of the base layer 83 (the central portion in the present embodiment). A positive electrode conductive portion 56 that is not covered with the plastic resin layer 4 is provided, and an inner adhesive is provided on the surface of the base layer 83 (the surface on the first thermoplastic resin layer 4 side) except for the positive electrode conductive portion 56. The first thermoplastic resin layer 4 is laminated via the layer 84. Further, the first heat-resistant resin layer 8 is laminated on the other surface of the first metal foil layer 2 via the outer adhesive layer 90, and a part of the other surface of the first metal foil layer 2 (this In the embodiment, the central portion) is provided with the positive terminal portion 9 not covered with the first heat-resistant resin layer 8 and the outer adhesive layer 90 (see FIG. 1). The corrosion-resistant layer 81 is a layer made of a metal oxide or a Si oxide, the intermediate layer 82 is a layer containing a hydrolyzate of a metal alkoxide or a hydrolyzate of a Si alkoxide, and the base layer 83 is a layer. , A layer containing one or more components selected from the group consisting of metal and Si, and a water-soluble resin. Details of the configurations of the corrosion-resistant layer 81, the intermediate layer 82, and the base layer 83 will be described later. In FIGS. 1 and 2, 80 is a functional layer, and the functional layer is a corrosion resistant layer 81 / intermediate layer 82 / base layer in order from the first metal foil layer 2 side to the first thermoplastic resin layer 4 side. It is composed of 83 / inner adhesive layer 84.

The main body 51 is formed by performing molding such as overhang molding and drawing molding on the exterior material 50 of the flat sheet to form a recess 52, and the undeformed portion around the recess 52 is trimmed to the outer circumference of the flange 53. Is. On the other hand, the lid 55 is made by cutting the exterior material 50 of a flat sheet to a required size. A negative electrode conductive portion 54 is provided on the inner surface of the bottom of the recess 52 of the main body 51, and a positive electrode conductive portion 56 is provided on the inner surface of the lid 55 (see FIG. 2). The positive electrode conductive portion 56 and the negative electrode conductive portion 54 are formed by exposed portions in which the base layer 83 of the exterior material 50 is exposed (see FIG. 1). Further, the positive electrode terminal portion 9 and the negative electrode terminal portion 19 are formed by exposed portions in which the metal foil layers 2 and 12 of the exterior material 50 are exposed (see FIG. 1).

In the bare cell 60, a sheet-shaped positive electrode 61 and a sheet-shaped negative electrode 62 are laminated via a separator 63, and the bare cell 60 is housed in a space between the two exterior materials 50 to accommodate the positive electrode 61. Is connected to the positive electrode conductive portion 56 of the exterior material 50, and the end of the negative electrode 62 is connected to the negative electrode conductive portion 54 of the exterior material 50 (see FIG. 2).

In the power storage device 1, after joining the positive electrode 61 and the negative electrode 62 of the bare cell 60 to the positive electrode conductive portion 56 and the negative electrode conductive portion 54, respectively, the bare cell 60 is housed in the recess 52 of the main body 51 and covered with the lid 55 to inject electrolyte. The thermoplastic resin layers 4 and 14 at the contact portion between the flange 53 of the main body 51 and the lid 55 are heat-sealed with the inlet left, and the electrolyte injection port is heat-sealed after the electrolyte is injected. Is.

In the power storage device 1, since the exterior material 50 is provided with the positive electrode terminal portion 9 and the negative electrode terminal portion 19, it is possible to connect to other devices so as to be energized via these terminal portions.

The means for joining the positive electrode 61 and the positive electrode conductive portion 56 and the means for joining the negative electrode 62 and the negative electrode conductive portion 54 are not particularly limited, but are, for example, ultrasonic bonding, soldering, or a conductive adhesive. Adhesion and the like can be exemplified.

In the power storage device 1, since the conductive parts (metal layers) 54 and 56 connecting the bare cell (device body part) 60 are formed as a part of the exterior material, energization is possible without using a tab lead. By eliminating the tab lead, it is possible to reduce the weight and size of the power storage device 1. Further, the corrosion resistant layer 81 / intermediate layer 82 / base layer 83 is laminated in this order on one surface of the metal foil layers 2 and 12 (the surface on the device body 60 side; the surface on the thermoplastic resin layer side), and the base layer is formed. The surface of the 83 has a structure in which the thermoplastic resin layers 4 and 14 are laminated via the inner adhesive layer 84 in the region excluding the conductive portions 56 and 54, and the corrosion resistant layer 81 is made of a metal oxide or a Si oxide. Since it is a layer, the corrosion resistance of the metal foil can be improved, and the base layer 83 is a layer containing one or more components selected from the group consisting of metal and Si, and a water-soluble resin. Therefore, it can be stably adhered to the inner adhesive layer 84. Here, since the base layer 83 is laminated on the corrosion resistant layer 81 via the intermediate layer (layer containing the hydrolyzate of metal alkoxide or the hydrolyzate of Si alkoxide) 82, sufficient adhesive strength can be obtained. , The metal foil layers 2 and 12 and the thermoplastic resin layers 4 and 14 are joined with sufficient adhesive force. The exterior material 50 is excellent in corrosion resistance of the metal foil, excellent in electrolytic solution resistance, and the like, and can secure sufficient adhesive strength.

An embodiment of the exterior material 50 for a power storage device of the present invention is shown in FIG. The exterior material 1 for a power storage device has a corrosion resistant layer 81 / intermediate layer 82 / base layer 83 / inner adhesive layer 84 / thermoplastic resin layer 4 (14) on one surface of the metal foil layer 2 (12). A part of the surface of the base layer 83 (the central portion in the present embodiment) is laminated in order, and a conductive portion 56 (54) not covered with the thermoplastic resin layer 4 (14) and the inner adhesive layer 84 is provided. It is provided. Further, the heat-resistant resin layer 8 (18) is laminated on the other surface of the metal foil layer 2 (12) via the outer adhesive layer 90, and one of the other surfaces of the metal foil layer 2 (12). A terminal portion 9 (19) not covered with the heat-resistant resin layer 8 (18) and the outer adhesive layer 90 is provided in a portion (central portion in the present embodiment) (see FIG. 1). As shown in FIG. 1, the functional layer 80 is formed by the corrosion resistant layer 81 / intermediate layer 82 / base layer 83 / inner adhesive layer 84. In FIG. 2, each layer of the corrosion resistant layer 81, the intermediate layer 82, the base layer 83, and the inner adhesive layer 84 is not described, but for convenience, these layers are collectively described as the functional layer 80, and the functional layer 80 is described. The detailed configuration, mode, etc. of the above are as shown in FIG.

In the present invention, the corrosion resistant layer 81 is a layer made of a metal oxide or a Si oxide, and the intermediate layer 82 is a layer containing a hydrolyzate of a metal alkoxide or a hydrolyzate of a Si alkoxide. The base layer 83 is a layer containing one or more components selected from the group consisting of metal and Si, and a water-soluble resin.

In the exterior material 50 for a power storage device of the present invention, the organic matter content in the corrosion-resistant layer 81 is "X" (mass%), the organic matter content in the intermediate layer 82 is "Y" (mass%), and the base layer. When the organic matter content in 83 is "Z" (mass%), a configuration having an X <Y <Z relationship is preferable. The adhesive force between the metal foil layers 2 and 12 and the thermoplastic resin layers 4 and 14 can be further enhanced. For the "organic matter content" (mass%) in each of the above layers, the mass reduction due to TG (reduced mass) was measured in accordance with JIS K7120-1987, and the mass reduction (reduced mass) of the layer was measured. When "M" is set and the mass of the layer before the above measurement is set to "N",
Organic matter content = (M / N) x 100
It is a value (mass%) obtained by the above formula.

The metal foil layers 2 and 12 play a role of imparting a gas barrier property to prevent the invasion of oxygen and water into the exterior material 50. The metal foil layers 2 and 12 are not particularly limited, but for example, copper foil, iron foil, silver foil, aluminum foil (Al foil), various alloy foils, and the like, as well as on at least one side of the metal foil. Examples thereof include those in which a plating layer made of at least one metal selected from the group consisting of Ni, Cr, Zn and Sn is formed. Above all, as the metal foil layers 2 and 12, it is preferable to use a metal foil such as a copper foil, an iron foil, or a silver foil. The thickness of the metal foil layers 2 and 12 is preferably 20 μm to 100 μm. When it is 20 μm or more, it is possible to prevent the occurrence of pinholes during rolling when manufacturing a metal foil, and when it is 100 μm or less, the stress during molding such as overhang molding and draw forming can be reduced and the moldability is improved. be able to. Above all, the thickness of the metal foil layers 2 and 12 is particularly preferably 20 μm to 50 μm.

Considering the ionization tendency of the metal, when the aluminum foil is used for the positive electrode, the copper foil or the iron foil is suitable as the metal foil layer (metal foil layer 12 in FIG. 2) for the exterior material on the negative electrode side.

The corrosion-resistant layer 81 laminated on one surface (the surface on the inner layers 4 and 14 sides) of the metal foil layers 2 and 12 is a layer made of a metal oxide or a Si oxide. The corrosion-resistant layer 81 mainly plays a role of preventing corrosion (including discoloration due to corrosion) of the metal foil layers 2 and 12. The corrosion-resistant layer 81 is not particularly limited, but for example, a chromate film (chromate chromate film, phosphate chromate film, electrolytic chromate film, etc.), titanate film, zirconate film, alumina film, silicate film, cerium oxidation. Examples include a physical film and a metal oxide film obtained by passibate treatment. The thickness of the corrosion resistant layer 81 is preferably 0.01 μm to 5 μm.

The intermediate layer 82 mainly plays a role of enhancing the adhesive force between the corrosion resistant layer 81 and the base layer 83. The intermediate layer 82 is a layer containing a hydrolyzate of metal alkoxide or a hydrolyzate of Si alkoxide. Metal alkoxides and Si alkoxides are represented by the general formula R'M (OR) n, where here.
Examples of "M" include Si, Ti, Zr, Cr, Ce, Al and the like.
Examples of "R'" include a vinyl group, a styryl group, a methacrylic group, an epoxy group, an amino group and the like.
Examples of "R" include methane, ethane, etc.
R in R'M (OR) n is released by hydrolysis and this site is bonded to the metal or Si of the corrosion resistant layer 81, while R'is a functional group (for example, a carbonyl group) of the water-soluble resin of the underlying layer 83. Bonds with hydroxyl groups, amino groups, etc.). As a result, the corrosion resistant layer 81 and the base layer 83 are joined with sufficient bonding force via the intermediate layer 82.

Further, the intermediate layer 82 is a layer that can be formed by applying, for example, a coupling agent such as a silane coupling agent, a titanate coupling agent, a zirconate coupling agent, or an aluminate coupling agent. After applying the coupling agent, the corrosion-resistant layer 81 and the base layer 83 are bonded (bonded) with sufficient bonding force via the intermediate layer 82 by the above-mentioned hydrolysis. The thickness of the intermediate layer 82 is preferably 0.01 μm to 5 μm.

The base layer 83 mainly plays a role of stably adhering and bonding to the inner adhesive layer 84. The base layer 83 is a layer containing one or more components selected from the group consisting of metal and Si, and a water-soluble resin. Examples of one or more components selected from the group consisting of metal and Si include Cr, Zr, Ti, Ce, Zn, Si and the like. The water-soluble resin is not particularly limited, and examples thereof include acrylic acid-based resins, epoxy-based resins, melamine-based resins, and polyester-based resins.

As a treatment liquid for forming the base layer 83, for example,
1) Phosphoric acid and
With chromic acid
An aqueous solution of a mixture containing at least one compound selected from the group consisting of a metal salt of fluoride and a non-metal salt of fluoride 2) 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 containing at least one compound selected from the group consisting of chromic acid and chromium (III) salt 3) phosphoric acid.
At least one resin selected from the group consisting of acrylic resins, chitosan derivative resins and phenolic resins, and
At least one compound selected from the group consisting of chromic acid and chromium (III) salt, and
An aqueous solution of a mixture containing at least one compound selected from the group consisting of a metal salt of fluoride and a non-metal salt of fluoride An aqueous solution of any one of 1) to 3) above can be exemplified. The base layer 83 can be formed by applying this aqueous solution to the surface of the intermediate layer 82 (after drying) and then drying it.

The thickness of the base layer 83 is preferably 0.1 μm to 10 μm.

The inner adhesive layer 84 is not particularly limited, and examples thereof include a polyurethane adhesive layer, a polyester polyurethane adhesive layer, a polyether polyurethane adhesive layer, and a polyolefin-based adhesive layer. Above all, it is preferable to use a polyolefin-based adhesive that does not swell due to the electrolytic solution. The thickness of the inner adhesive layer 84 is preferably set to 1 μm to 5 μm. Above all, from the viewpoint of thinning and weight reduction of the exterior material, the thickness of the inner adhesive layer 84 is particularly preferably set to 1 μm to 3 μm.

The thermoplastic resin layers (thermosetting resin layers) (inner layers) 4 and 14 are provided with excellent chemical resistance against a highly corrosive electrolytic solution used in a lithium ion secondary battery or the like. At the same time, it plays a role of imparting heat-sealing property to the exterior material.

The thermoplastic resin layers 4 and 14 are not particularly limited, but are preferably thermoplastic resin non-stretched film layers. The thermoplastic resin non-stretched film layer 3 is not particularly limited, but is at least one thermoplastic selected from the group consisting of polyethylene, polypropylene, olefin-based copolymers, acid-modified products thereof, and ionomers. It is preferably composed of a non-stretched film made of resin. The thermoplastic resin layers 4 and 14 may be a single layer or a plurality of layers.

The thickness of the thermoplastic resin layers 4 and 14 is preferably set to 10 μm to 80 μm. When it is set to 10 μm or more, the occurrence of pinholes can be sufficiently prevented, and when it is set to 80 μm or less, the amount of resin used can be reduced and the cost can be reduced. Above all, it is particularly preferable that the thickness of the thermoplastic resin layers 4 and 14 is set to 25 μm to 50 μm.

As the heat-resistant resin constituting the heat-resistant resin layers (outer layers) 8 and 18, a heat-resistant resin that does not melt at the heat-sealing temperature when the exterior material is heat-sealed is used. As the heat-resistant resin, it is preferable to use a heat-resistant resin having a melting point of 10 ° C. or higher higher than the melting point of the thermoplastic resin constituting the thermoplastic resin layer, and heat resistance having a melting point of 20 ° C. or higher higher than the melting point of the thermoplastic resin. It is particularly preferable to use a sex resin.

The heat-resistant resin layers (outer layers) 8 and 18 are not particularly limited, and examples thereof include polyamide films such as nylon films, polyester films, and polyolefin films, and these stretched films are preferably used. Be done. Among them, the heat-resistant resin layers 8 and 18 include a biaxially stretched polyamide film such as a biaxially stretched nylon film, a biaxially stretched polybutylene terephthalate (PBT) film, a biaxially stretched polyethylene terephthalate (PET) film, and a biaxially stretched film. It is particularly preferable to use a polyethylene naphthalate (PEN) film or a biaxially stretched polypropylene film. The nylon film is not particularly limited, and examples thereof include a 6-nylon film, a 6,6 nylon film, and an MXD nylon film. The heat-resistant resin layers 8 and 18 may be formed of a single layer, or may be formed of, for example, a multi-layer made of a polyester film / polyamide film (a multi-layer made of a PET film / nylon film, etc.). You may have. In the above-exemplified multi-layer structure, the polyester film is preferably arranged outside the polyamide film, and similarly, the PET film is preferably arranged outside the nylon film.

The thickness of the heat-resistant resin layers 8 and 18 is preferably 8 μm to 50 μm. Sufficient strength as an exterior material can be secured by setting it to the above-mentioned preferable lower limit value or more, and stress during molding such as overhang molding and draw forming can be reduced and formability is improved by setting it to the above-mentioned preferable upper limit value or less. Can be made to. Above all, the thickness of the heat-resistant resin layers 8 and 18 is particularly preferably 12 μm to 25 μm.

The outer adhesive layer 90 is not particularly limited, and examples thereof include a polyurethane adhesive layer, a polyester polyurethane adhesive layer, and a polyether polyurethane adhesive layer. The thickness of the outer adhesive layer 90 is preferably set to 1 μm to 5 μm. Above all, from the viewpoint of thinning and weight reduction of the exterior material, the thickness of the outer adhesive layer 90 is particularly preferably set to 1 μm to 3 μm.

In the present invention, the base layer 83 may be formed on the other surface (the surface on the outer layer side) of the metal foil layer 2 (12). That is, even if the other surface side of the metal foil layer 2 (12) has a laminated mode of the metal foil layer 2 (12) / base layer 83 / outer adhesive layer 90 / heat-resistant resin layer 8 (18). Good.

Further, in the above embodiment, the exterior material 1 for the power storage device has a corrosion resistant layer 81 / intermediate layer 82 / base layer 83 / inner adhesive layer 84 / thermoplastic resin layer on one surface of the metal foil layer 2 (12). 4 (14) are laminated in this order, and a conductive portion 56 (54) not covered with the thermoplastic resin layer 4 (14) and the inner adhesive layer 84 is provided on a part of the surface of the base layer 83. However, instead of this component, one surface of the metal foil layer 2 (12) has a corrosion resistant layer 81 / a base layer 83 / an inner adhesive layer 84 / a thermoplastic resin layer 4 (14). ) Are laminated in this order, and a conductive portion 56 (54) not covered with the thermoplastic resin layer 4 (14) and the inner adhesive layer 84 is provided on a part of the surface of the base layer 83. It may be adopted. That is, a configuration in which the intermediate layer 82 is not provided at all may be adopted.

Further, in the above embodiment, the intermediate layer 82 is laminated on the entire surface of one surface of the metal foil layer 2 (12) via the corrosion resistant layer 81. For example, the conductive portion 56 is used. In the region corresponding to (54), the corrosion resistant layer 81 / the base layer 83 are laminated in this order on one surface of the metal foil layer 2 (12) (a configuration in which the intermediate layer 82 is not provided only in this corresponding region). It may be adopted. In this case, the conductive portion 56 (54) is formed by the exposed portion on the surface of the base layer 83 in the corresponding region.

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

<Example 1>
Immerse a copper foil with a thickness of 35 μm in an aqueous solution of chromic anhydride (concentration of chromic anhydride 3 g / L) controlled at a temperature of 20 ° C to 40 ° C, and perform electrolytic chromate treatment under the condition of a current density of 15 A / dm ^2. A chromate film (corrosion resistant layer) having a thickness of 1 μm was formed on one surface of a copper foil having a thickness of 35 μm. The organic matter content of the corrosion resistant layer is 0% by mass.

Next, a 1 vol% aqueous solution of a silane coupling agent (3-aminopropyl ethoxysilane) is applied onto the chromate film (corrosion resistant layer) in the copper foil, and then the chromate film (corrosion resistant layer) is heated and dried at 130 ° C. An intermediate layer having a thickness of 1 μm containing a Sialkoxide hydrolyzate was formed on the corrosion-resistant layer. The organic matter content of the intermediate layer is 50% by mass.

Next, on the surface of the intermediate layer (on the surface of the obtained copper foil / corrosion resistant layer / intermediate layer on the intermediate layer side), phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water, After applying a chemical conversion treatment liquid composed of alcohol, it was dried at 180 ° C. to form a chemical conversion film (underlayer) having a thickness of 1 μm containing Cr and an acrylic resin. The amount of chromium adhered to this base layer was 3 mg / m ² . The organic matter content of the base layer is 90% by mass.

Further, a polyester-urethane adhesive was applied to the other surface of the copper foil. At the time of this coating, the central portion of the other surface of the copper foil was designated as an adhesive-uncoated region by masking (masking tape affixed). After that, a biaxially stretched polyamide film (heat resistant resin layer; outer layer) having a thickness of 15 μm was attached to the polyester-urethane adhesive coated surface.

Next, on the surface of the base layer (on the surface of the obtained copper foil / corrosion resistant layer / intermediate layer / base layer side of the base layer), a two-component curable type maleic acid-modified polypropylene adhesive (many hardeners). Functional isocyanate) was applied. At the time of this coating, the central portion of the surface of the base layer was made into an adhesive-uncoated region by masking (masking tape was attached). After that, a 30 μm-thick unstretched polypropylene film (thermoplastic resin layer; inner layer) is superposed on the maleic anhydride-modified polypropylene adhesive coated surface, and between the rubber nip roll and the laminate roll heated to 100 ° C. The laminate was dry-laminated by sandwiching it between the two, and then aging (heating) at 40 ° C. for 5 days to obtain a laminate.

Next, the peripheral edge of the adhesive-uncoated region of the biaxially stretched polyamide film (heat-resistant resin layer; outer layer) in the laminate was irradiated with a laser to cut the biaxially stretched polyamide film, and the adhesive-uncoated region was formed. A biaxially stretched polyamide film was removed to form a positive terminal portion 9. Further, the unstretched polypropylene film (thermoplastic resin layer; inner layer) in the laminate is irradiated with a laser on the periphery of the adhesive-uncoated region to cut the unstretched polypropylene film, and the unstretched polypropylene film in the adhesive-uncoated region is cut. The polypropylene film was removed to form the positive electrode conductive portion 56, and an exterior material 1 for a power storage device having a thickness of 86 μm shown in FIG. 1 was obtained.

<Example 2>
Instead of the chromic acid anhydride aqueous solution (chromic acid anhydride concentration 3 g / L), EDTA (ethylenediaminetetraacetic acid) for improving dispersibility was added to the chromic acid anhydride aqueous solution (chromic acid anhydride concentration 3 g / L). By performing the chemical conversion treatment using the aqueous solution, the corrosion-resistant layer is composed of a chromate film having a thickness of 1 μm having an organic substance content of 5% by mass, and the chemical conversion treatment used in Example 1 as the chemical conversion treatment liquid. An exterior material 1 for a power storage device having a thickness of 86 μm having the configuration shown in FIG. 1 was obtained in the same manner as in Example 1 except that the liquid further contained 1% by mass of EDTA (ethylenediaminetetraacetic acid) was used. .. In the obtained exterior material for a power storage device, the organic matter content of the base layer is 95% by mass.

<Example 3>
By using an iron foil (Fe foil) having a thickness of 35 μm instead of the copper foil having a thickness of 35 μm and performing a silicate treatment using an aqueous solution of sodium silicate having a concentration of 5 vol% instead of the aqueous solution of chromic anhydride. The exterior for a power storage device having a thickness of 85 μm shown in FIG. 1 in the same manner as in Example 1 except that the corrosion-resistant layer is composed of a silicate film having a thickness of 0.1 μm having an organic substance content of 0% by mass. Material 1 was obtained.

<Example 4>
By performing a film formation treatment by a wet method using a titania colloidal dispersion having a concentration of 5 vol% instead of the aqueous solution of chromic anhydride, the corrosion-resistant layer is composed of a titanate film having a thickness of 2 μm having an organic substance content of 0% by mass. An exterior material 1 for a power storage device having a thickness of 87 μm shown in FIG. 1 was obtained in the same manner as in Example 2 except that the configuration was adopted.

<Example 5>
By performing a film formation treatment by a wet method using a zirconia colloidal dispersion having a concentration of 5 vol% instead of the aqueous solution of chromic anhydride, the corrosion-resistant layer is composed of a zirconate film having a thickness of 2 μm having an organic substance content of 0% by mass. An exterior material 1 for a power storage device having a thickness of 87 μm shown in FIG. 1 was obtained in the same manner as in Example 1 except that the configuration was adopted.

<Example 6>
Exterior material 1 for power storage device having a thickness of 86 μm having the configuration shown in FIG. 1 in the same manner as in Example 1 except that a SUS foil (stainless steel foil) having a thickness of 35 μm was used instead of the copper foil having a thickness of 35 μm. Got

<Example 7>
In the same manner as in Example 1, a Zn-plated layer (1 μm each) was formed on both sides of a steel foil (Fe foil) having a thickness of 35 μm instead of the copper foil having a thickness of 35 μm. An exterior material 1 for a power storage device having a thickness of 88 μm having the configuration shown in FIG. 1 was obtained.

<Example 8>
Instead of chemical conversion treatment liquid consisting of phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water, and alcohol, from phosphoric acid, polyacrylic acid (acrylic resin), cerium oxide, water, and alcohol. Example 1 except that the base layer is composed of a base layer having a thickness of 1 μm (a base layer containing Ce and an acrylic resin) having an organic substance content of 90% by mass by using the chemical conversion treatment liquid. In the same manner as above, an exterior material 1 for a power storage device having a thickness of 86 μm and having the configuration shown in FIG. 1 was obtained.

<Example 9>
An exterior material 1 for a power storage device having a thickness of 86 μm having the configuration shown in FIG. 1 was obtained in the same manner as in Example 1 except that a titanate coupling agent (titanium lactate) was used instead of the silane coupling agent. The organic matter content of the intermediate layer in the obtained exterior material for a power storage device is 65% by mass.

<Example 10>
Instead of the chromic anhydride aqueous solution (chromic anhydride concentration 3 g / L), EDTA (ethylenediamine tetraacetic acid) for improving dispersibility was added to the chromic anhydride aqueous solution (chromic anhydride concentration 3 g / L). By performing the chemical conversion treatment with the aqueous solution, the corrosion-resistant layer is composed of a chromate film having a thickness of 1 μm having an organic substance content of 5% by mass, and a zirconate coupling agent is used instead of the silane coupling agent. An exterior material 1 for a power storage device having a thickness of 86 μm having the configuration shown in FIG. 1 was obtained in the same manner as in Example 1 except that (zyroxide monoacetyl acetate) was used. The organic matter content of the intermediate layer in the obtained exterior material for a power storage device is 70% by mass.

<Example 11>
The exterior for a power storage device having a thickness of 86 μm having the configuration shown in FIG. 1 in the same manner as in Example 1 except that aluminum tris (ethylacetacetate), which is an aluminate coupling agent, was used instead of the silane coupling agent. Material 1 was obtained. The organic matter content of the intermediate layer in the obtained exterior material for a power storage device is 60% by mass.

<Example 12>
Instead of a chemical conversion treatment solution consisting of phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water, and alcohol, it is composed of phosphoric acid, polyacrylic acid (acrylic resin), silica, water, and alcohol. Except that the base layer was composed of a base layer having a thickness of 1 μm (a base layer containing Si and an acrylic resin) having an organic substance content of 90% by mass by using the chemical conversion treatment liquid, as in Example 1. In the same manner, an exterior material 1 for a power storage device having a thickness of 86 μm shown in FIG. 1 was obtained.

<Example 13>
Exterior material 1 for power storage device with a thickness of 80 μm having the configuration shown in FIG. 1 in the same manner as in Example 3 except that an aluminum foil (Al foil) having a thickness of 30 μm was used instead of the copper foil having a thickness of 35 μm. Got

<Example 14>
The exterior material 1 for a power storage device having a thickness of 85 μm having the configuration shown in FIG. 1 was used in the same manner as in Example 3 except that a silver foil (Ag foil) having a thickness of 35 μm was used instead of the copper foil having a thickness of 35 μm. Obtained.

<Example 15>
A chemical conversion treatment solution composed of phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water, and alcohol was applied to the surface of the copper foil / corrosion-resistant layer obtained in Example 1 on the corrosion-resistant layer side. After that, it was dried at 180 ° C. to form a chemical conversion film (underlayer) containing Cr and an acrylic resin. The amount of chromium adhered to this base layer was 3 mg / m ² .

Next, a two-component curable maleic acid-modified polypropylene adhesive (curing agent is a polyfunctional isocyanate) is applied to the surface of the base layer (on the surface of the obtained copper foil / corrosion resistant layer / base layer on the base layer side). An unstretched polypropylene film (inner layer) having a thickness of 30 μm is laminated, sandwiched between a rubber nip roll and a laminate roll heated to 100 ° C., and pressure-bonded to dry-laminate the material. A laminate was obtained by aging (heating) at ° C. for 5 days.

Next, the peripheral edge of the adhesive-uncoated region of the biaxially stretched polyamide film (heat-resistant resin layer; outer layer) in the laminate was irradiated with a laser to cut the biaxially stretched polyamide film, and the adhesive-uncoated region was formed. A biaxially stretched polyamide film was removed to form a positive terminal portion 9. Further, the unstretched polypropylene film (thermoplastic resin layer; inner layer) in the laminated body is irradiated with a laser on the periphery of the adhesive-uncoated region to cut the unstretched polypropylene film, and the unstretched polypropylene film in the adhesive-uncoated region is cut. The polypropylene film was removed to form the positive electrode conductive portion 56, and an exterior material for a power storage device having a thickness of 85 μm was obtained. That is, as compared with Example 1, an exterior material for a power storage device having no intermediate layer was obtained.

<Example 16>
By performing the silicate treatment using an aqueous solution of sodium silicate having a concentration of 5 vol% instead of the aqueous solution of chromic anhydride, the corrosion-resistant layer is composed of a silicate film having a thickness of 0.1 μm having an organic substance content of 0% by mass. An exterior material 1 for a power storage device having a thickness of 84 μm was obtained in the same manner as in Example 15.

<Example 17>
Instead of a chemical conversion treatment solution consisting of phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water, and alcohol, it is composed of phosphoric acid, polyacrylic acid (acrylic resin), silica, water, and alcohol. Example 15 and the like, except that the base layer was composed of a base layer having a thickness of 1 μm (a base layer containing Si and an acrylic resin) having an organic substance content of 90% by mass by using the chemical conversion treatment liquid. Similarly, an exterior material 1 for a power storage device having a thickness of 85 μm was obtained.

<Example 18>
By performing silicate treatment using an aqueous solution of sodium silicate having a concentration of 5 vol% instead of the aqueous solution of chromic anhydride, the corrosion-resistant layer is composed of a silicate film having a thickness of 0.1 μm having an organic matter content of 0% by mass. In addition, instead of a chemical conversion treatment solution consisting of phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water, and alcohol, phosphoric acid, polyacrylic acid (acrylic resin), silica, water, By using a chemical conversion treatment liquid composed of alcohol, the process was carried out except that the base layer was composed of a base layer having a thickness of 1 μm (a base layer containing Si and an acrylic resin) having an organic substance content of 90% by mass. In the same manner as in Example 15, an exterior material 1 for a power storage device having a thickness of 84 μm was obtained.

<Comparative example 1>
A 30 μm-thick unstretched polypropylene film (inner layer) is laminated on one surface of a 35 μm-thick copper foil via a two-component curable maleic acid-modified polypropylene adhesive (the curing agent is a polyfunctional isocyanate). Then, it was sandwiched between a rubber nip roll and a laminate roll heated to 100 ° C. and crimped to obtain a dry laminate, and then aged (heated) at 40 ° C. for 5 days to obtain a laminate. ..

Next, the peripheral edge of the adhesive-uncoated region of the biaxially stretched polyamide film (heat-resistant resin layer; outer layer) in the laminate was irradiated with a laser to cut the biaxially stretched polyamide film, and the adhesive-uncoated region was formed. A biaxially stretched polyamide film was removed to form a positive terminal portion. Further, the unstretched polypropylene film (thermoplastic resin layer; inner layer) in the laminate is irradiated with a laser on the periphery of the adhesive-uncoated region to cut the unstretched polypropylene film, and the unstretched polypropylene film in the adhesive-uncoated region is cut. The polypropylene film was removed to form a positive conductive portion to obtain an exterior material for a power storage device having a thickness of 83 μm. That is, as compared with Example 1, an exterior material for a power storage device having no corrosion resistant layer, an intermediate layer and a base layer was obtained.

<Comparative example 2>
A chemical conversion treatment solution consisting of phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water, and alcohol is applied to one surface of a copper foil having a thickness of 35 μm, and then dried at 180 ° C. A chemical conversion film (underlayer) containing Cr and an acrylic resin was formed. The amount of chromium adhered to this base layer was 3 mg / m ² . Next, on the surface of the base layer (on the surface of the obtained copper foil / base layer on the base layer side), a two-component curable maleic acid-modified polypropylene adhesive (curing agent is a polyfunctional isocyanate) is interposed. An unstretched polypropylene film (inner layer) having a thickness of 30 μm is laminated, sandwiched between a rubber nip roll and a laminate roll heated to 100 ° C. and pressure-bonded to dry laminate, and then at 40 ° C. 5 A laminate was obtained by aging (heating) for days.

Next, the peripheral edge of the adhesive-uncoated region of the biaxially stretched polyamide film (heat-resistant resin layer; outer layer) in the laminate was irradiated with a laser to cut the biaxially stretched polyamide film, and the adhesive-uncoated region was formed. A biaxially stretched polyamide film was removed to form a positive terminal portion. Further, the unstretched polypropylene film (thermoplastic resin layer; inner layer) in the laminate is irradiated with a laser on the periphery of the adhesive-uncoated region to cut the unstretched polypropylene film, and the unstretched polypropylene film in the adhesive-uncoated region is cut. The polypropylene film was removed to form a positive conductive portion to obtain an exterior material for a power storage device having a thickness of 84 μm. That is, as compared with Example 1, an exterior material for a power storage device having a structure in which a corrosion resistant layer and an intermediate layer were not provided was obtained.

<Comparative example 3>
Immerse a copper foil with a thickness of 35 μm in an aqueous solution of chromic anhydride (concentration of chromic anhydride 3 g / L) controlled at a temperature of 20 ° C to 40 ° C, and perform electrolytic chromate treatment under the condition of a current density of 15 A / dm ^2. A chromate film (corrosion resistant layer) having a thickness of 1 μm was formed on one surface of a copper foil having a thickness of 35 μm.

Next, on the chromate film (corrosion resistant layer) of the copper foil, a non-stretched polypropylene film (inner layer) having a thickness of 30 μm is interposed via a two-component curable maleic acid-modified polypropylene adhesive (the curing agent is a polyfunctional isocyanate). ) Are laminated, sandwiched between a rubber nip roll and a laminate roll heated to 100 ° C. and crimped to dry laminate, and then aged (heated) at 40 ° C. for 5 days to laminate. I got a body.

Next, the peripheral edge of the adhesive-uncoated region of the biaxially stretched polyamide film (heat-resistant resin layer; outer layer) in the laminate was irradiated with a laser to cut the biaxially stretched polyamide film, and the adhesive-uncoated region was formed. A biaxially stretched polyamide film was removed to form a positive terminal portion. Further, the unstretched polypropylene film (thermoplastic resin layer; inner layer) in the laminate is irradiated with a laser on the periphery of the adhesive-uncoated region to cut the unstretched polypropylene film, and the unstretched polypropylene film in the adhesive-uncoated region is cut. The polypropylene film was removed to form a positive conductive portion to obtain an exterior material for a power storage device having a thickness of 84 μm. That is, as compared with Example 1, an exterior material for a power storage device having no intermediate layer and a base layer was obtained.

<Comparative example 4>
On the surface of the copper foil / corrosion resistant layer / intermediate layer obtained in Example 1 on the intermediate layer side, a two-component curable maleic acid-modified polypropylene adhesive (curing agent is a polyfunctional isocyanate) has a thickness of 30 μm. An unstretched polypropylene film (inner layer) is laminated, sandwiched between a rubber nip roll and a laminate roll heated to 100 ° C. and pressure-bonded to dry-laminate, and then aged at 40 ° C. for 5 days ( By heating), a laminate was obtained.

Next, the peripheral edge of the adhesive-uncoated region of the biaxially stretched polyamide film (heat-resistant resin layer; outer layer) in the laminate was irradiated with a laser to cut the biaxially stretched polyamide film, and the adhesive-uncoated region was formed. A biaxially stretched polyamide film was removed to form a positive terminal portion. Further, the unstretched polypropylene film (thermoplastic resin layer; inner layer) in the laminate is irradiated with a laser on the periphery of the adhesive-uncoated region to cut the unstretched polypropylene film, and the unstretched polypropylene film in the adhesive-uncoated region is cut. The polypropylene film was removed to form a positive electrode conductive portion to obtain an exterior material for a power storage device having a thickness of 85 μm. That is, as compared with Example 1, an exterior material for a power storage device having no base layer was obtained.

<Comparative example 5>
A 1 vol% aqueous solution of a silane coupling agent (3-aminopropyl ethoxysilane) is applied to one surface of a copper foil having a thickness of 35 μm, and then heated and dried at 130 ° C. to obtain one surface of the copper foil. , A 1 μm-thick intermediate layer containing a Sialkoxide hydrolyzate was formed.

Next, the surface of the intermediate layer (on the surface of the obtained copper foil / intermediate layer on the intermediate layer side) is composed of phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water, and alcohol. After applying the chemical conversion treatment liquid, it was dried at 180 ° C. to form a chemical conversion film (underlayer) containing Cr and an acrylic resin. The amount of chromium adhered to this base layer was 3 mg / m ² .

Next, a two-component curable maleic acid-modified polypropylene adhesive (curing agent is polyfunctional isocyanate) is applied to the surface of the base layer (on the surface of the obtained copper foil / intermediate layer / base layer on the base layer side). An unstretched polypropylene film (inner layer) having a thickness of 30 μm is laminated, sandwiched between a rubber nip roll and a laminate roll heated to 100 ° C., and pressure-bonded to dry-laminate the material. A laminate was obtained by aging (heating) at ° C. for 5 days.

Next, the peripheral edge of the adhesive-uncoated region of the biaxially stretched polyamide film (heat-resistant resin layer; outer layer) in the laminate was irradiated with a laser to cut the biaxially stretched polyamide film, and the adhesive-uncoated region was formed. A biaxially stretched polyamide film was removed to form a positive terminal portion. Further, the unstretched polypropylene film (thermoplastic resin layer; inner layer) in the laminate is irradiated with a laser on the periphery of the adhesive-uncoated region to cut the unstretched polypropylene film, and the unstretched polypropylene film in the adhesive-uncoated region is cut. The polypropylene film was removed to form a positive electrode conductive portion to obtain an exterior material for a power storage device having a thickness of 85 μm. That is, as compared with Example 1, an exterior material for a power storage device having no corrosion resistant layer was obtained.

The performance of each power storage device exterior material obtained as described above was evaluated based on the following evaluation method. The results are shown in Tables 1 to 3.

<Corrosion resistance evaluation method>
For each Example and Comparative Example, a test piece having a length of 100 mm and a width of 15 mm was cut out from the exterior material for a power storage device, and the test piece was immersed in an electrolytic solution with one end in the length direction of the test piece peeled off. Then, it was allowed to stand in an oven at 85 ° C. for 4 hours in this electrolytic solution exposed state. As the electrolytic solution, lithium hexafluorophosphate (LiPF ₆ ) has a concentration of 1 in a mixed solvent in which ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) are mixed in equal volume ratios. An electrolytic solution dissolved in molar / L was used.

After 4 hours, the test piece is taken out from the oven, the taken-out test piece is washed with water, and then the metal foil at one end of the test piece is visually observed to check for discoloration. Those with no discoloration were marked with "x" and marked with "○" (passed).

<Resistance measurement method>
A resistance value (mΩ) was measured between the positive electrode terminal portion 9 and the positive electrode conductive portion 56 of the exterior material for the power storage device using a “Milliohm High Tester 3540” manufactured by Hioki Electric Co., Ltd. (manufactured by HIOKI). Those with a resistance value of 100 mΩ or less were rejected, and those with a resistance value exceeding 100 mΩ were rejected.

<Measurement method of peel strength after immersion in electrolytic solution>
A test piece having a length of 100 mm and a width of 15 mm was cut out from the exterior material for the power storage device for each Example and Comparative Example, and a grip margin for measuring the peel strength was provided at one end of the test piece in the length direction. The test piece was immersed in an electrolytic solution and allowed to stand in an oven at 85 ° C. for 4 hours in an exposed state of the electrolytic solution. As the electrolytic solution, lithium hexafluorophosphate (LiPF ₆ ) has a concentration of 1 in a mixed solvent containing ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) in equal volume ratios. An electrolytic solution dissolved in molar / L was used.

After 4 hours had passed, the test piece was taken out from the oven, the test piece was washed with water, and then allowed to stand in a thermostatic environment at 25 ° C. for 24 hours. After that, the test piece was peeled off at the interface between the metal foil layer and the inner layer (polypropylene film) in the constant temperature room, and the peeling strength was measured. At this time, the tensile speed was set to 150 mm / min, and the peel strength (N / 15 mm width) was measured by peeling 180 degrees. 3 (N / 15 mm width) or more was accepted, and less than 3 (N / 15 mm width) was rejected.

<Comprehensive judgment>
Corrosion resistance is "○" (pass), electrolyte resistance is pass, resistance value is small and sufficient energization is possible, and the overall judgment is "○". Corrosion resistance, electrolyte resistance, small resistance value Those that failed any of (sufficient electrical conductivity) were evaluated as "x".

As is clear from Tables 1 to 3, the exterior materials for power storage devices of Examples 1 to 18 according to the present invention have low resistance between the terminal portion and the conductive portion, but discolor even when exposed to an electrolytic solution. Since there is no corrosion (no corrosion is observed) and the corrosion resistance is excellent, and the peel strength (adhesive strength between layers) after immersion in the electrolytic solution can be maintained, no tab lead is used between the terminal part and the conductive part. However, energization is sufficiently possible.

On the other hand, as is clear from Table 3, in Comparative Examples 1 to 5, the peel strength after immersion in the electrolytic solution was insufficient. Moreover, in Comparative Examples 1, 2 and 5, the corrosion resistance was not good.

As a specific example, the exterior material for a power storage device according to the present invention is, for example,
-Used as an exterior material for various power storage devices such as power storage devices such as lithium secondary batteries (lithium ion batteries, lithium polymer batteries, etc.), lithium ion capacitors, and electric double layer capacitors. Further, the power storage device according to the present invention includes an all-solid-state battery in addition to the power storage device exemplified above.

1 ... Power storage device 2 ... First metal foil layer (metal foil layer)
4 ... First thermoplastic resin layer (thermoplastic resin layer; inner layer)
8 ... First heat-resistant resin layer (heat-resistant resin layer; outer layer)
9 ... Positive electrode terminal (terminal)
12 ... Second metal foil layer (metal foil layer)
14 ... Second thermoplastic resin layer (thermoplastic resin layer; inner layer)
18 ... Second heat-resistant resin layer (heat-resistant resin layer; outer layer)
19 ... Negative electrode terminal (terminal)
50 ... Exterior material for power storage device 54 ... Negative electrode conductive part (conductive part)
56 ... Positive electrode conductive part (conductive part)
60 ... Device body (bare cell)
80 ... Functional layer 81 ... Corrosion resistant layer 82 ... Intermediate layer 83 ... Underlayer 84 ... Inner adhesive layer 90 ... Outer adhesive layer

Claims (8)

A corrosion resistant layer / intermediate layer / base layer / inner adhesive layer / thermoplastic resin layer is laminated in this order on one surface of the metal foil layer, and the inner adhesive layer and the heat are formed on a part of the surface of the base layer. An exterior material for a power storage device provided with a conductive portion that is not coated with a plastic resin layer.
The corrosion-resistant layer is a layer made of a metal oxide or a Si oxide.
The intermediate layer is a layer containing a hydrolyzate of metal alkoxide or a hydrolyzate of Si alkoxide.
An exterior material for a power storage device, wherein the base layer is a layer containing one or more components selected from the group consisting of metal and Si, and a water-soluble resin. The exterior material for a power storage device according to claim 1 , wherein the metal in the metal alkoxide is at least one metal selected from the group consisting of Cr, Zr, Ti, Ce and Al. When the organic matter content in the corrosion-resistant layer is "X", the organic matter content in the intermediate layer is "Y", and the organic matter content in the base layer is "Z",
X <Y <Z
The exterior material for a power storage device according to claim 1 or 2 , which is related to the above. The exterior material for a power storage device according to any one of claims 1 to 3 , wherein the content of organic substances in the corrosion-resistant layer is less than 50% by mass, and the content of organic substances in the base layer is 50% by mass or more. The exterior material for a power storage device according to any one of claims 1 to 4 , wherein the metal foil layer is made of copper foil or iron foil. The metal foil layer is any one of claims 1 to 4, wherein a plating layer made of at least one metal selected from the group consisting of Ni, Cr, Zn and Sn is formed on at least one surface of the metal foil. The exterior material for a power storage device according to item 1. A claim in which a heat-resistant resin layer is laminated on the other surface of the metal foil layer, and a terminal portion not covered with the heat-resistant resin layer is provided on a part of the other surface of the metal foil layer. Item 8. The exterior material for a power storage device according to any one of Items 1 to 6 . The two exterior materials for power storage devices according to any one of claims 1 to 7 , and the two exterior materials.
With the device body
The device main body is housed in a space between the two exterior materials arranged so that the thermoplastic resin layers face each other, and the electrodes of the device main body and the conductive part of the exterior material are connected to each other. , A power storage device characterized in that the thermoplastic resin layers at the peripheral edges of the two exterior materials are joined and sealed.