TW201537809A - External packaging material of electrochemical device and electrochemical device - Google Patents

Abstract

The present invention provides an external packaging material of electrochemical device, which is characterized in comprising: a metal foil layer 4 and a thermoplastic non-expandable thin-film layer 3 as the inner layer; in the external packaging material of electrochemical device, the surface of at least one side of the metal foil layer 4 is formed with a metal coating layer 8. With such a composition, the external packaging material of electrochemical device of the present invention may be sufficiently light-weighted, and the permeation of external moisture and electrolyte diffusion may also be prevented.

Description

External material for electrochemical device and electrochemical device

The present invention relates to a thin and lightweight exterior material and an electrochemical device externally mounted by the exterior material, which is used for a battery or a capacitor used in a portable device such as a smart phone or a tablet computer; or A battery or capacitor used in power storage for hybrid vehicles, electric vehicles, wind power generation, solar power generation, and nighttime electricity.

In the present specification, the "outer layer" does not mean that it is the outermost layer of the exterior material, but means that it is disposed outside the metal foil layer.

Further, in the present invention, the meaning of "aluminum" includes aluminum and alloys thereof.

In addition to the thinner and lighter mobile electronic devices such as smart phones and tablet terminals, the electrochemical devices such as lithium ion batteries, lithium polymer batteries, lithium ion capacitors, and electric double layer capacitors are installed. At present, we are working on a laminated exterior material in which two sides of an aluminum foil are bonded to a plastic film to replace the conventional metal can and achieve the purpose of weight reduction. In addition, batteries such as electric vehicles and the like, large power sources for power storage, capacitors, and the like which are packaged by using the laminated exterior material having the above-described configuration are also used.

The laminated exterior material is generally configured to be bonded to a heat-resistant stretch film on one side of the aluminum foil as a shield layer, and to heat sealable heat on the other side of the aluminum foil. In the case of a laminate having a total thickness of about 100 μm, it has a function of preventing moisture or various gases from entering the inside and preventing leakage of the electrolyte (see Patent Document 1). Further, the thickness of the outer casing of the first embodiment of Patent Document 1 was about 98 μm, and the thickness of the outer casing of Example 2 was about 103 μm.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2002-25511

However, the above-mentioned mobile electronic devices and the like have been moving toward thinner and lighter weights in recent years, and the electrochemical devices mounted therein are also required to be thinner and lighter, and accordingly, the exterior materials for electrochemical devices are used. Thin film formation and light weight are also being developed for this purpose. Further, an aluminum foil of 30 μm or more which does not generate pinholes has been used to form an exterior material. Further, it is known that an aluminum foil of less than 30 μm may have pinholes, and the thinner the thickness, the more the number of pinholes will increase. In the case where pinholes are present, the aluminum foil cannot function as a shield layer, and thus it is impossible to prevent moisture from entering from the outside, and problems such as diffusion and leakage of the electrolyte cannot be prevented.

On the other hand, in order to prevent pinholes from being formed in the aluminum foil and the thickness of the aluminum foil needs to be 30 μm or more, the total thickness of the exterior material is at least 80 μm or more, making it difficult to further develop. Thin film and light weight.

Therefore, even when it is used as an exterior material for a small-sized electrochemical device such as a lithium ion battery having a small capacity of about 30 mA to 500 mA, it is actually used for a large-sized electrochemical device such as a lithium ion battery having a capacity of more than 500 mA. In order to reduce the thickness and weight of the exterior material for a small-sized electrochemical device having a capacity of 30 mA to 500 mA, the size of the material is the same.

The present invention has been made in view of the above-described technical background, and an object of the invention is to provide an exterior material for an electrochemical device which can be sufficiently lightened and which suppresses intrusion of moisture from the outside and prevents diffusion of the electrolyte.

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

[1] An exterior material for an electrochemical device, comprising: a metal foil layer; and a thermoplastic resin unstretched film layer as an inner layer; and in the exterior material for an electrochemical device, the metal A surface of at least one side of the foil layer is formed with a metal plating layer.

[2] An exterior material for an electrochemical device, comprising: an outer layer; a thermoplastic resin unstretched film layer as an inner layer; and a metal foil layer disposed between the outer layer and the inner layer; In the exterior material for an electrochemical device, a metal plating layer is formed on at least one surface of the metal foil layer.

[3] The exterior material for an electrochemical device according to [2], wherein the outer layer is a heat resistant resin film layer.

[4] The exterior material for an electrochemical device according to [2], wherein the outer layer is coated with a heat resistant resin coating layer formed of a heat resistant resin.

[5] The exterior material for an electrochemical device according to any one of the preceding claims, wherein the thickness of the metal foil layer is 5 μm or more and less than 30 μm.

[6] The exterior material for an electrochemical device according to any one of the preceding claims, wherein the metal plating layer has a thickness of 0.5 μm to 5 μm.

[7] The exterior material for an electrochemical device according to any one of the preceding claims, wherein the metal plating layer is selected from the group consisting of nickel, zinc, tin, chromium, and cobalt. The coating formed by the material.

[8] The exterior material for an electrochemical device according to any one of the preceding claims, wherein the outer casing has a thickness of 30 μm to 80 μm.

[9] An electrochemical device comprising: an electrochemical device main body portion, any one of the above items 1 to 8 and the external material for an electrochemical device; and the electrochemical device body portion is The aforementioned exterior material is externally mounted.

According to the inventions of [1] and [2], since at least one surface of the metal thin layer is formed with a metal plating layer, even if the metal foil is thinned, pinholes are formed in the metal foil layer. The metal plating can suppress the intrusion of moisture from the outside, and at the same time, the electrolyte can be prevented from diffusing and leaking to the outside. Thus, the above effects can be improved by the presence of the metal plating layer, so that even if the thickness of the metal foil layer is designed to be thinner (for example, 5 μm or more and less than 30 μ) m) It can be made lightweight, and it can also be used as an exterior material to suppress the intrusion of moisture from the outside while preventing the diffusion of the electrolyte. Therefore, according to the present invention, it is possible to achieve sufficient film formation and weight reduction, and to secure excellent moisture barrier properties and excellent electrolyte solution diffusion preventing properties. By using the electrochemical device externally mounted on the outer casing of the present invention which is thinned and lightened, the weight energy density and the volume energy density of the electrochemical device can be improved. Further, since the surface of at least one side of the metal foil layer is formed of a metal plating layer, the puncture resistance of the metal foil itself can be further improved.

Further, according to the invention of [2], since the outer layer is provided, sufficient puncture strength as the exterior material can be secured, and puncture resistance can be improved.

According to the invention of [3], since the outer layer is a heat-resistant resin film layer, the puncture strength as an exterior material can be improved.

According to the invention of [4], since the outer layer is coated with the heat-resistant resin coating layer formed of the heat-resistant resin, the puncture strength as the exterior material can be improved. Further, the heat-resistant resin coating layer can be further thinned as compared with the case where the heat-resistant resin film layer constitutes the outer layer.

According to the invention of [5], the thickness of the metal foil layer is 5 μm or more and less than 30 μm, and excellent moisture barrier properties and excellent electrolyte solution diffusion preventing properties can be secured, and thinning and weight reduction can be further achieved.

According to the invention of [6], the thickness of the metal plating layer is from 0.5 μm to 5 μm, and it is possible to achieve sufficient film formation and weight reduction, and to secure excellent moisture barrier properties and excellent electrolyte solution diffusion preventing properties.

According to the invention of [7], the metal plating layer is selected from the group consisting of metal materials of at least one of a group consisting of nickel, zinc, tin, chromium, and cobalt, thereby ensuring further excellent moisture barrier properties and more. Further excellent electrolyte diffusion prevention, and at the same time can be improved as The puncture strength of the exterior material.

According to the invention of [8], the thickness of the exterior material is 30 μm to 80 μm, and the weight energy density and the volume energy density of the electrochemical device can be further improved by using an electrochemical device which is externally mounted.

According to the invention (electrochemical device) of [9], an external device can provide an electrochemical device which can ensure more excellent moisture barrier properties and excellent electrolyte diffusion prevention, and simultaneously improve the electrochemical device. Weight energy density and volume energy density.

1‧‧‧External materials for electrochemical devices

2‧‧‧Outer layer

3‧‧‧ thermoplastic resin unstretched film layer (inner layer)

4‧‧‧metal foil layer

5‧‧‧1st adhesive layer

6‧‧‧2nd adhesive layer

8‧‧‧Metal plating

10‧‧‧Shield

12‧‧‧Heat resistant resin film layer

13‧‧‧Heat resistant resin coating

30‧‧‧Electrochemical device

31‧‧‧Electrical device body (electrochemical device)

T‧‧‧ thickness of plating

Fig. 1 shows an embodiment of an exterior material for an electrochemical device according to the present invention (first embodiment) Sectional view of the type).

Fig. 2 is a cross-sectional view showing another embodiment (second embodiment) of the exterior material for an electrochemical device of the present invention.

Fig. 3 is a cross-sectional view showing another embodiment (third embodiment) of the exterior material for an electrochemical device of the present invention.

Fig. 4 is a cross-sectional view showing another embodiment (fourth embodiment) of the exterior material for an electrochemical device of the present invention.

Fig. 5 is a cross-sectional view showing an embodiment of an electrochemical device of the present invention.

Fig. 6 is a perspective view showing a state in which a material other than the electrochemical device of Fig. 5 (planar shape), an electrochemical device main body portion, and an exterior material (formed into a three-dimensional shape) are separated before heat sealing.

An embodiment of the exterior material 1 for an electrochemical device of the present invention is shown in Fig. 1. The exterior material 1 for an electrochemical device is formed by forming metal plating layers 8 and 8 on both surfaces of the metal foil layer 4 as a shield layer 10, and integrating the first adhesive layer 5 and the outer layer 2 on one surface thereof. At the same time, the surface of the other side of the shield layer 10 is formed by laminating and integrating the second adhesive layer 6 and the thermoplastic resin unstretched film layer (inner layer) 3 . In the present embodiment, the outer layer 2 is composed of the heat resistant resin film layer 12.

In the embodiment shown in Fig. 1, the shield layer 10 is formed by forming the metal plating layers 8 and 8 on both surfaces of the metal foil layer 4, but is not particularly limited to such a configuration, and may be as shown in Figs. The metal plating layer 8 is formed only on the surface of one side of the metal foil layer 4.

That is, in the embodiment shown in Fig. 2, the exterior material 1 for an electrochemical device is formed by forming a metal plating layer 8 as a shielding layer 10 on one side of the metal foil layer 4, and on the side surface (metal The surface of the plating layer 8 is integrated with the outer layer 2 via the first adhesive layer 5, and the surface of the other side of the shield layer 10 (the surface of the metal foil layer 4) is interposed between the second adhesive layer 6 and The thermoplastic resin unstretched film layer (inner layer) 3 is laminated and integrated. In the present embodiment, the outer layer 2 is composed of the heat resistant resin film layer 12.

Further, in the embodiment shown in Fig. 3, the exterior material 1 for an electrochemical device is formed by the metal plating layer 8 on one surface of the metal foil layer 4 as the shield layer 10, and on the other side. (the surface of the metal foil layer 4) is laminated and integrated with the outer layer 2 via the first adhesive layer 5, and the second adhesive layer 6 is interposed between the surface of the shield layer 10 (the surface of the metal plating layer 8). It is formed by laminating a film layer (inner layer) 3 of a thermoplastic resin unstretched. In the present embodiment, the outer layer 2 is composed of the heat resistant resin film layer 12.

On the other hand, in the embodiment shown in Fig. 4, the exterior material 1 for an electrochemical device is formed by forming the metal plating layers 8, 8 as the shielding layer 10 on both sides of the metal foil layer 4, and on the side surface thereof. The heat-resistant resin coating layer 13 of the outer layer 2 is laminated and integrated, and the surface of the other side of the shield layer 10 is laminated with the thermoplastic film unstretched film layer (inner layer) via the second adhesive layer 6 . And constitute.

In the present invention, as described above, the metal plating layer 8 is formed on at least one surface of the metal foil layer 4, and even if the metal foil is thinned, pinholes are present in the metal foil layer 4, and the depth direction of the pinholes The end opening (in the thickness direction of the metal foil) can be considered to be almost closed by the metal plating 8. Further, it is considered that the inside of the pinhole in the metal foil layer 4 (the inner region of the hole deeper from the end of the pinhole), the metal plating layer 8 may also intrude therein to form a slightly closed or closed state.

The exterior material 1 for an electrochemical device is formed by forming a metal plating layer 8 on at least one surface of the metal foil layer 4. Therefore, even if the metal foil is thinned, the metal foil layer 4 has pinholes. The metal plating layer 4 can suppress the intrusion of moisture from the outside, and at the same time suppress the diffusion and leakage of the electrolyte to the outside. In this way, the above-described effects are improved by the presence of the metal plating layer 4, and even if the thickness of the metal foil layer 4 is designed to be thinner (for example, 5 μm or more and less than 30 μm), it is lightweight, and it can be used as the exterior material 1 It inhibits the intrusion of moisture from the outside while preventing the diffusion of the electrolyte. Therefore, according to the present invention, it is possible to achieve sufficient thin film formation and weight reduction, and to secure excellent moisture barrier properties and excellent electrolyte solution diffusion preventing properties. By using the electrochemical device 30 which is externally mounted by the thinned and lightweight outer casing 1 of the present invention, the weight energy density and the volume energy density of the electrochemical device can be improved. Further, since the surface of at least one side of the metal foil layer 4 is formed with the metal plating layer 8, the puncture resistance of the metal foil itself can be further improved.

Further, in the embodiment shown in FIGS. 1 to 4, the outer layer 2 is provided regardless of any type, so that the outer casing 1 can have sufficient puncture strength and the puncture resistance can be sufficiently improved.

Further, in the laminated structure shown in Figs. 1 and 4, the metal plating layer 8 formed on the surface of one side of the metal foil layer 4 and the metal foil layer 4 as the completion of the shielding function is the metal foil layer 4 The metal plating layer 8 formed on the other side surface is present in three layers, and is laminated with the layers shown in FIGS. 2 and 3 (as the function of completing the shielding function is: the metal foil layer 4, the side of the metal foil layer 4) In comparison with the two layers of the metal plating layer 8 formed on the surface, it has an advantage of ensuring more excellent moisture barrier properties and more excellent electrolyte solution diffusion preventing properties.

Further, in the present invention, when the thickness of the metal foil layer 4 is set to less than 30 μm in order to achieve sufficient weight reduction, pinholes may occur in the metal foil, and on the other hand, the metal plating layer 8 cannot be denied. There is a possibility that a small amount of peeling occurs due to a stress change or the like. However, in the configurations of FIGS. 2 and 3 (the configuration in which the metal foil layer 4 and the metal plating layer 8 are double-shielded), the pinhole position of the metal foil layer 4 is present. The possibility that the (specific point) overlaps with the peeling point position (specific point) of the metal plating layer 8 does not actually occur, and therefore excellent moisture barrier properties and excellent electrolyte solution diffusion preventing properties can be secured.

Further, in the configuration of FIGS. 1 and 4, the following three-shielding portion is provided: the metal foil layer 4, the metal plating layer 8 formed on one surface of the metal foil layer 4, and the metal foil layer 4 The metal plating layer 8 formed on the other side surface, the pinhole position (specific point) of the metal foil layer 4 and the peeling point position (specific point) of the metal plating layer 8 on the one side and the metal plating layer 8 of the other side The position of the peeling point (specific point), the possibility that all three overlap at the same position does not actually occur, so the configuration of the triple shield portion (the configuration of Figs. 1 and 4) is provided, and Figs. 2 and 3 In comparison with the configuration (the configuration in which the two heavy shielding portions are provided), it is possible to ensure more excellent moisture barrier properties and more excellent electrolyte solution diffusion preventing properties.

In the present invention, the metal foil layer 4 is responsible for preventing oxygen gas or moisture from intruding into the exterior material 1 and imparting gas barrier properties thereto. The thickness of the metal foil layer 4 is preferably 5 μm or more and 30 μm or less. By setting it in the thickness range, thinning and weight reduction can be achieved, and the thickness of the metal plating layer 8 can be adjusted by increasing or decreasing, thereby ensuring excellent moisture barrier properties and excellent electrolyte diffusion of the exterior material 1 as a whole. Preventive. The thickness of the metal foil layer 4 is more preferably 5 μm or more and less than 20 μm, and particularly preferably 5 μm to 18 μm. The metal foil is not particularly limited, and examples thereof include an aluminum foil, a stainless steel foil, a nickel foil, a copper foil, and a titanium foil. Among them, aluminum foil is preferred from the viewpoint of weight reduction and cost.

The outer layer 2 and the inner layer (thermoplastic resin unstretched film layer) 3 are layers made of a resin. Although these resin layers are extremely small, there is a possibility that light, oxygen, or liquid may enter the outside of the outer casing. There is also the possibility of infiltration of internal contents (electrolyte, food, medicine, etc. of the battery). The arrival of such intrusions into the metal foil layer 4 causes corrosion of the metal foil layer 4. In the present invention, it is preferable that the metal foil is formed into a film on at least the surface on the side of the thermoplastic resin layer 3, and in this case, the corrosion resistance of the metal foil layer 4 can be improved. Among them, a configuration in which the chemical conversion film is formed on both surfaces of the metal foil is particularly preferable, and in this case, the corrosion resistance of the metal foil layer 4 can be sufficiently improved.

The chemical conversion film is a film formed by performing a chemical conversion treatment on the surface of the metal foil. For example, the metal foil may be chromate-treated, and the zirconium compound may be subjected to a non-chromium chemical conversion treatment. For example, in the chromate treatment, an aqueous solution of the mixture of any one of the following 1) to 3) may be applied to the surface of the metal foil subjected to the degreasing treatment, followed by drying.

1) at least one compound in a group containing a metal salt selected from the group consisting of phosphoric acid, chromic acid, fluoride, and fluoride, and an aqueous solution of a mixture thereof

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

3) at least one resin selected from the group consisting of phosphoric acid, acrylic resin, chitosan derivative resin, and phenol resin, and at least one compound selected from the group consisting of chromic acid and chromium (III) salt. And an aqueous solution of 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 chemical conversion film, the amount of chromium adhesion (single side) is preferably 0.1 mg/m ² to 50 mg/m ^{2 , and particularly} preferably 2 mg/m ² to 20 mg/m ² .

The metal constituting the metal plating layer 8 is not particularly limited, and examples thereof include nickel, zinc, tin, chromium, cobalt, gold, silver, platinum, and the like. In particular, the metal plating layer 8 is preferably a plating layer made of a metal material selected from the group consisting of nickel, zinc, tin, chromium, and cobalt, and at least one of the specific metals is used. Further, it is possible to further improve the moisture barrier property and further excellent electrolyte solution diffusion preventing property, and at the same time, to improve the puncture strength as the exterior material 1.

The thickness of the metal plating layer 8 (the thickness of the metal plating layer formed on one surface when the metal plating layer is formed on both surfaces) is preferably set to 0.5 μm to 5 μm. When the thickness of the metal foil layer 4 is less than 30 μm, pinholes may occur in the metal foil. However, by adjusting the thickness of the metal foil, the thickness T of the metal plating layer 8 is adjusted and adjusted to ensure the exterior. The material as a whole has excellent moisture barrier properties and excellent electrolyte diffusion preventing properties. Wherein, the foregoing metal plating layer 8 The thickness (the thickness of the metal plating layer formed on one side when the metal plating layer is formed on both sides) T is preferably set to 2 μm to 5 μm from the viewpoint of sufficiently closing the pinhole of the metal foil layer 4 (refer to FIGS. 1 to 4). . Further, when the metal constituting the metal plating layer 8 is nickel, it has an advantage of further improving the puncture strength as compared with the case of using other metals.

The means for the metal plating is not particularly limited, and examples thereof include an electroless plating method, a plating method, and a vacuum plating method. Among them, the metal plating layer 8 is preferably formed by electroless plating. The metal plating layer formed by electroless plating can form a more uniform plating layer without unevenness than those formed by the electroplating method, and can surely ensure excellent moisture barrier properties and excellent electrolyte diffusion preventing property, particularly metal foil. When the layer 4 is an aluminum foil layer, the metal plating layer (the metal plating layer formed by the electroless plating method) 8 of the aluminum foil layer 4 can have an advantageous effect of providing high adhesion.

The thermoplastic resin is not stretched with a film layer (inner layer) 3, and has excellent chemical resistance even when it is used for a lithium ion battery or the like, and has excellent chemical resistance, and at the same time, imparts heat sealing properties to the exterior material. By.

The resin constituting the thermoplastic resin unstretched film layer 3 is not particularly limited, and examples thereof include polyethylene, polypropylene, ionomer, ethylene ethyl acrylate (EEA), ethylene methyl acrylate (EAA), and ethylene. Methyl methacrylate resin (EMMA), ethylene vinyl acetate copolymer resin (EVA), maleic anhydride-modified polypropylene, maleic anhydride-denatured polyethylene, and the like.

The thickness of the thermoplastic resin unstretched film layer 3 is preferably set to 20 μm to 80 μm. By setting it at 20 μm or more, the occurrence of pinholes can be sufficiently prevented, and by setting it to 80 μm or less, the amount of the resin can be lowered to achieve cost reduction. among them, It is particularly preferable that the thickness of the thermoplastic resin unstretched film layer 3 is set to 30 μm to 50 μm. Further, the thermoplastic resin may not have the film layer 3 extended, and may be a single layer or a plurality of layers.

In the present invention, the outer layer 2 is a main component for ensuring good moldability as an exterior material, that is, it is intended to prevent breakage of the metal foil during necking due to necking. Further, in the present invention, the outer layer 2 is not necessarily an essential constituent layer, but it is preferably provided.

The outer layer 2 is preferably formed of a heat-resistant resin film layer 12 or a heat-resistant resin coating layer 13 formed of a heat-resistant resin. At this time, there is an advantage that the puncture strength as the exterior material 1 can be improved.

The heat-resistant resin film layer 12 is not particularly limited, and for example, a stretched polyamide film (such as a stretched nylon film) or an extended polyester film is preferably used. The heat-resistant resin film layer 12 is formed by using a biaxially stretched polyimide film (a biaxially stretched nylon film or the like), a biaxially stretched polybutylene terephthalate (PBT) film, and a biaxially oriented polycondensation. A polyethylene terephthalate (PET) film or a biaxially stretched polyphthalic acid (PEN) film is particularly preferred. The nylon is not particularly limited, and examples thereof include 6 nylon, 6,6 nylon, MXD nylon, and the like. Further, the heat-resistant resin film layer 12 may be formed of a single layer (single stretched film), or may be a plurality of layers (two-axis stretch PET film/two) formed by, for example, an extended polyester film/extensive polyamide film. It is formed by a plurality of layers formed by a shaft extending nylon film.

The heat-resistant resin film layer 12 includes a biaxially stretched polyester film disposed on the outer side and a biaxially stretched polyimide film disposed on the side of the first adhesive layer 5, and the plurality of layers are formed. It is better. Further, the heat-resistant resin film layer 12 includes a biaxially-oriented polyethylene terephthalate disposed on the outer side and a biaxially stretched nylon film disposed on the side of the first adhesive layer 5, and the like. The plural layer constitutes a better one.

Further, the heat-resistant resin film layer 12 may be formed of a heat-resistant resin unstretched film such as a polycarbonate unstretched film or a polyimide-unstretched film.

The thickness of the heat resistant resin film layer 12 is preferably set to 12 μm to 50 μm.

The heat resistant resin coating layer 13 is a coating layer formed by applying a heat resistant resin. For example, it can be formed by applying a heat resistant resin to the surface of the metal foil layer 4. Alternatively, the metal plating layer 8 may be formed on at least one side surface of the metal thin layer 4 to form a surface of the shielding layer 10 (the surface of the metal plating layer 8) by applying a heat-resistant resin.

The heat-resistant resin constituting the heat-resistant resin coating layer 13 is not particularly limited, and examples thereof include an acrylic resin, an epoxy resin, a urethane resin, a polyolefin resin, and a fluorine resin. Among them, a fluorine-based resin having a base made of tetrafluoroethylene or vinyl fluoride vinyl ether is preferred in view of the advantages of heat resistance and chemical resistance. Further, in order to change the appearance of the exterior material, the design property is improved, and an additive such as fine particles (such as cerium oxide or acrylic beads) or ink may be added to the heat-resistant resin.

The means for the resin coating layer is not particularly limited, and examples thereof include a gravure roll method, a reverse roll coating method, a lip roll coating method, and a die coating method. The thickness of the heat-resistant resin coating layer 13 is preferably set to 0.1 μm to 40 μm. The thickness of the heat-resistant resin coating layer 13 is preferably set to 0.1 μm to 20 μm.

It is also possible to form a vapor deposition layer on the outer surface or/and the inner surface (the surface on the side of the metal foil layer 4) of the outer layer 2. By providing such a vapor deposition layer, it is possible to ensure further excellent moisture barrier properties and further excellent electrolyte solution diffusion preventing properties. The vapor deposition layer is preferably composed of a material selected from the group consisting of a metal, a metal oxide, and a fluoride. The aforementioned metal, Although not particularly limited, for example, aluminum, chromium, zinc, nickel, gold, silver, platinum, or the like can be given. Further, the metal oxide is not particularly limited, and examples thereof include alumina, ceria, titania, and zirconia. The fluoride is not particularly limited, and examples thereof include magnesium fluoride and the like. Among them, the material (vapor deposition material) forming the vapor deposition layer is particularly preferably a material selected from the group consisting of aluminum, aluminum oxide, and cerium oxide.

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

The second adhesive layer 6 is not particularly limited, but may be exemplified by the first adhesive layer 5, and a polyolefin-based adhesive layer which is less swelled by an electrolytic solution is preferably used. The thickness of the second adhesive layer 6 is preferably set to 1 μm to 5 μm. In particular, the thickness of the second adhesive layer 6 is particularly preferably set to 1 μm to 3 μm from the viewpoint of thinning and weight reduction of the exterior material.

The shielding layer 10 (the shielding layer 10 formed of the metal plating layer 8 on the surface of at least one side of the metal foil layer 4) and the outer layer 2 (the heat resistant resin film layer 12, the heat resistant resin coating layer 13, etc.) are attached. The method of combination is not particularly limited, but a method called dry lamination is recommended. Specifically, the prepared first adhesive is applied to the upper surface of the shield layer 10 or the lower surface of the outer layer 2, or the surfaces on the both sides, and the solvent is evaporated and dried to a film, and then the shield layer 10 is The outer layer 2 is attached. Next, it hardens according to the hardening conditions of a 1st adhesive agent. Thereby, the shield layer 10 can be joined to the outer layer 2 via the first adhesive layer 5. Again, the first one The means for applying the agent may, for example, be a gravure coating method, a reverse roll coating method, a lip roll coating method, or the like.

The method of bonding the shield layer 10 (the shield layer 10 on which the surface of the metal foil layer 8 is formed on at least one side of the metal foil layer 4) and the thermoplastic resin unstretched film 3 is not particularly limited, but may be combined with the shield layer. 10 is the same as the outer layer 2, and a dry lamination method in which the second adhesive is applied and dried, and the shield layer 10 and the thermoplastic resin unstretched film layer 3 are bonded together can be exemplified.

The thermoplastic resin layer 3 and the outer layer 2 may be added with an additive. The additives are not particularly limited, and examples thereof include anti-blocking agents (cerium oxide, talc, kaolin, acrylic beads, etc.), lubricants (fatty acid amides, waxes, etc.), and antioxidants (hindered phenols, etc.). Wait.

The thickness of the exterior material 1 of the present invention is preferably set to 30 μm to 80 μm. When the thickness is 80 μm or less, the weight energy density and the volume energy density of the electrochemical device 30 using the additional material 1 can be improved. The thickness of the exterior material 1 is preferably set to 30 μm to 65 μm.

Further, in the exterior material 1 of the present invention, the outer layer 2 is not an essential constituent layer, and the shield layer 10 (the shield layer 10 formed of the metal plating layer 8 on the surface of at least one side of the metal foil layer 4) may be employed. The surface on one side is formed by laminating the second adhesive layer 6 and the unstretched film layer (inner layer) 3 of the thermoplastic resin.

Further, in the above embodiment, the first adhesive layer 5 and the second adhesive layer 6 are provided. However, the two layers 5 and 6 are unnecessary constituent layers, and may be omitted. Composition.

Further, the exterior material 1 of the present invention is not particularly limited to the products shown in FIGS. 1 to 4. The layer structure can be further added to enhance the function as an exterior material.

The exterior material 1 of the present invention can be formed into a molded case (battery case or the like) for an electrochemical device by molding (deep extension molding, bulging molding, or the like).

Next, Figs. 5 and 6 show an embodiment of the electrochemical device 30 of the present invention. As shown in Figs. 5 and 6, the housing portion of the molded casing 1A obtained by molding the exterior material 1 of the present invention accommodates an electrochemical device main body portion (electrochemical device) 31 having a substantially rectangular parallelepiped shape. The inner portion (lower side) of the exterior material 1 of the present invention on the inner layer 3 side is disposed above the portion 31, and the peripheral portion of the inner layer 3 of the planar exterior material 1 is formed on the outer periphery of the planar outer casing 1 and the molded outer casing 1A. The inner layer 3 of the rim portion (sealing peripheral portion) 29 is sealed by heat sealing and sealed to constitute the electrochemical device 30 of the present invention.

In Fig. 5, reference numeral 39 denotes a peripheral portion of the exterior material 1, and is joined (fused) to a rim portion (sealing peripheral portion) 29 of the molded casing 1A to form a heat seal portion.

The electrochemical device main body portion 31 is not particularly limited, and examples thereof include a battery main body portion, a capacitor main body portion, and a battery main body portion.

The width of the heat seal portion 39 is preferably set to 0.5 mm or more. More than 0.5mm can be surely sealed. Preferably, the width of the heat seal portion 39 is set to be 3 mm to 15 mm.

[Examples]

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

<Example 1>

A soft aluminum foil having a thickness of 15 μm (A8079 soft aluminum alloy foil specified in JIS H4000) 4 is subjected to electroless nickel plating (Kanigen plating) to form a nickel plating layer 8 having a thickness (T) of 2 μm on both surfaces of the soft aluminum foil 4, thereby A double-sided aluminum foil (shield layer 10) having a thickness of 19 μm was obtained.

Next, on both surfaces of the double-sided aluminum foil (shield layer 10), phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water, and alcohol are applied to form a treatment liquid, and then dried at 150 ° C. A double-sided aluminum foil having a chemical conversion film formed on both sides is prepared. The amount of chromium deposited on the film was 5 mg/m ^{2 on} one side.

Next, a two-liquid-curable polyester-urethane-based resin adhesive is applied to the surface on both sides of the two-side aluminum-plated foil on which the film is formed, and dried to form a first adhesive layer 5, which is a first adhesive. The surface of the layer 5 is bonded to the 2-axis stretched polyester film 2 having a thickness of 12 μm, and simultaneously coated on the other side of the aluminum foil, a two-liquid curing type polyolefin-based adhesive (acid-modified polypropylene as a main agent, six) The two-component curing agent of methylene diisocyanate as a curing agent was dried to form a second adhesive layer 6, and the surface of the second adhesive layer 6 was bonded to the unstretched polypropylene film 3 having a thickness of 25 μm. By placing the laminate in an environment of 40 ° C for 3 days (curing), an exterior material (thickness 62 μm) 1 for the electrochemical device shown in Fig. 1 was obtained.

<Example 2>

The exterior material (thickness: 54 μm) 1 for the electrochemical device shown in Fig. 1 was obtained in the same manner as in Example 1 except that a soft aluminum alloy foil having a thickness of 7 μm was used instead of the soft aluminum alloy foil having a thickness of 15 μm.

<Example 3>

Except that the thickness T of the nickel plating layer 8 was changed to 0.5 μm, In the same manner as in Example 1, an exterior material (thickness: 59 μm) 1 for the electrochemical device shown in Fig. 1 was obtained.

<Example 4>

The aluminum foil is coated on both sides, and a soft aluminum foil having a thickness of 15 μm (A8079 soft aluminum alloy foil specified in JIS H4000) 4 is subjected to electroless nickel plating (Kanigen plating), and the nickel plating layer 8 having a thickness of 1 μm is formed on both surfaces of the soft aluminum foil. Further, electroless tin plating was performed to further laminate a tin plating layer having a thickness of 1 μm on both sides to obtain a double-sided aluminum-plated foil having a thickness of 19 μm, and the same as in Example 1 except that the above-mentioned two-side aluminum-plated foil was used, and the electrification shown in FIG. 1 was obtained. The device is made of an exterior material (thickness 62 μm)1.

<Example 5>

The outer casing for the electrochemical device shown in Fig. 2 was obtained in the same manner as in the first embodiment except that the nickel plating layer 8 having a thickness of 2 μm was formed on one surface of the soft aluminum foil to form a single-sided aluminum foil. Thickness 60 μm)1. Moreover, the plated surface 8 side of the single-sided aluminum-plated foil was bonded to the 2-axis stretched polyester film 2 (see FIG. 2).

<Example 6>

Using tetrafluoroethylene and vinyl acetate copolymer as the main resin, toluene diisocyanate (TDI) and hexamethylene diisocyanate (HDI) are mixed as a hardener in a ratio of 1:1 by mass, and the mass of the main resin 100 is The mixture and 18 parts by mass of the above-mentioned curing agent were mixed to obtain a coating resin (heat resistant resin).

Then, 80 parts by mass of the coating resin (heat resistant resin), 10 parts by mass of barium sulfate, and 10 parts by mass of particulate cerium oxide were mixed to form a resin composition, and ethyl acetate was added as a solvent to adjust the solid content to 19 mass. % to prepare a resin solution.

Next, on both sides obtained in Example 1, a double-sided aluminum-plated foil formed into a film was formed. The surface of one side (the surface of the plating layer 8) is coated with the above-mentioned resin solution by a gravure roll method and dried to form a heat-resistant resin coating layer 13 having a thickness of 2 μm after being dried, and simultaneously with the other aluminum foil. One side of the surface (the surface of the plating layer 8) is coated with a two-liquid curing type polyolefin-based adhesive (acid-modified polypropylene as a main component, hexamethylene diisocyanate as a two-liquid hardening type adhesive for curing agent), and dried. Thereafter, the second adhesive layer 6 was formed, and the surface of the second adhesive layer 6 was bonded to the unstretched polypropylene film 3 having a thickness of 25 μm. By placing the laminate in an environment of 40 ° C for 3 days (curing), an exterior material (thickness: 50 μm) 1 for the electrochemical device shown in Fig. 4 was obtained.

<Comparative Example 1>

An exterior material for an electrochemical device was obtained in the same manner as in Example 1 except that a soft aluminum foil having a thickness of 15 μm (A8079 soft aluminum alloy foil specified in JIS H4000) was used instead of the double-sided aluminum foil having a thickness of 19 μm.

<Comparative Example 2>

An exterior material for an electrochemical device was obtained in the same manner as in Example 1 except that a soft aluminum foil having a thickness of 40 μm (A8079 soft aluminum alloy foil specified in JIS H4000) was used instead of the double-sided aluminum foil having a thickness of 19 μm.

The battery for each electrochemical device obtained above was used as a battery (analog battery) as described below. First, the exterior material is cut into a size of 120 mm in length × 100 mm in width, and the cut outer casing is embossed using a movable mold and a fixed mold, and the upper side is opened, and is 100 mm in length × The molded case 1A (see FIG. 6) having a spheroidal portion (sealing peripheral portion) 29 is formed in a substantially rectangular parallelepiped shape with a width of 80 mm and a depth of 2 mm. Further, the embossing is such that the inner surface of the bottom surface of the substantially rectangular parallelepiped shape in which the upper surface is opened is an unstretched polypropylene film (inner layer) 3. On the other hand, a cut product (hereinafter referred to as "planar outer material") having a size of 120 mm in length × 100 mm in width is not formed (see FIG. 6).

A soft aluminum foil having a thickness of 30 μm, a polypropylene film having a thickness of 100 μm, and a soft copper foil having a thickness of 30 μm were layered and laminated, and an analog electrode having a size of 95 mm in length × 75 mm in width was punched, and 10 dummy electrodes were laminated to obtain an electrochemistry. The device body portion (simulated product) 31 (see Fig. 6).

Further, as shown in Fig. 5, the electrochemical device main body portion 31 is filled with an embossed portion having a substantially rectangular parallelepiped shape opened from the upper surface of the molded outer casing 1A, and then the molded outer casing 1A and the planar shape are externally formed. In the material 1, the inner side layers 3 are opposed to each other, and the peripheral edge portion of the inner layer 3 of the planar outer casing 1 and the inner layer 3 of the rim portion 29 of the molded outer casing 1 are formed in four sides. The mixture was heated to 200 ° C on the other side, and heat-sealed by a metal hot plate at a pressure of 0.3 MPa for 3 seconds to form a heat seal portion 39, which was then placed in a drying chamber having a dew point of -60 ° C for 24 hours.

Next, in a drying chamber having a dew point of -60 ° C, an electrolyte solution was used by using an open portion of the unsealed one side of the heat-sealed joint body (a vinyl carbonate: dimethyl carbonate: dimethyl carbonate) In the mixed carbonate in which the mixing volume ratio is 1:1:1, the LiPF ₆ concentration obtained after adding LiPF ₆ is 1 mol/L of the electrolytic solution) 10 mL is poured into the inside, and then decompressed at 0.086 MPa. In the state, the unbonded one side portion of the heat-sealed joined body was heat-sealed by a metal hot plate heated at 200 ° C for 3 seconds at a pressure of 0.3 MPa, and after the sealing was completed, it was obtained as shown in FIG. Battery (analog battery) 30.

The battery (analog battery) obtained above was subjected to measurement of the moisture content in the electrolytic solution in the simulated battery according to the following evaluation test method, and the moisture barrier property evaluation was performed, and the electrolyte diffusion prevention property evaluation was performed. The results are shown in Table 2. 3 is shown.

<Evaluation test method for moisture barrier properties>

Each of the examples and the comparative examples was prepared separately with 9 samples (analog batteries), a first constant temperature and humidity chamber at 40 ° C and a humidity of 90%, a second constant temperature and humidity chamber at 60 ° C and a humidity of 90%, and 80 ° C. After three of the third constant temperature and humidity chambers having a humidity of 90% were placed, one was taken out one week, one was taken out after two weeks, and one was taken out three weeks, and the electrolyte inside the battery was taken out by 1 mL using a syringe. The amount of water in the electrolytic solution was measured using a Karl Fischer moisture meter ("AQ2250" manufactured by Hiranuma Sangyo Co., Ltd.).

In the results of Table 2, compared with the initial (before the start of the test), the amount of water after one week showed a significant increase in any sample, but this can be considered as a polypropylene for simulating a battery or an exterior material. The trace amount of moisture contained in the film dissolves in the electrolyte. Compared with the results of Comparative Example 1 (the amount of water after 1, 2, and 3 weeks), the simulated battery composed of the exterior materials of Examples 1 to 5 did not have an extreme (substantial) increase in moisture. It was confirmed that the exterior material of the present invention has an excellent moisture barrier effect.

<Evaluation test method for electrolyte diffusion prevention>

Three samples (analog batteries) were prepared individually for each of the examples and the comparative examples, and individual masses (hereinafter referred to as "initial masses") were measured using an electronic balance. Next, each sample was placed in a disk made of a single polypropylene, and each of the samples was individually placed in a first constant temperature and humidity chamber at 40 ° C, a second constant temperature and humidity chamber at 60 ° C, and a third constant temperature and humidity chamber at 80 ° C. After that, it was taken out one week later and then taken out for mass measurement, and quickly returned to the constant temperature bath. After 2 weeks, after 3 weeks, the mass measurement was performed in the same manner. At this time, the mass only reduces the amount of diffusion and leakage of the electrolyte, and the mass does not change when the electrolyte does not bleed out.

X={(quality after 1 week)-(initial quality)}÷(initial quality)×100

Y={(quality after 2 weeks)-(initial quality)}÷(initial quality)×100

Z={(mass after 3 weeks)-(initial quality)}÷(initial quality)×100

The mass change rate X (%) after one week, the mass change rate Y (%) after two weeks, and the mass change rate Z (%) after three weeks were calculated by the above formula.

As shown in Tables 1 to 3, the battery (analog battery) comprising the exterior material for electrochemical devices according to Examples 1 to 6 of the present invention was compared with the exterior material of Comparative Example 1 in which no metal plating layer was provided. The thickness of the exterior material is the same (light weight has been achieved), and the present invention has excellent moisture barrier properties and at the same time has excellent diffusion preventing property of the electrolytic solution. In other words, the battery (analog battery) comprising the exterior material for electrochemical devices according to the first to sixth embodiments of the present invention can have both excellent moisture barrier properties, excellent electrolyte solution diffusion preventing property, and sufficient weight reduction. These three advantages.

On the other hand, the exterior material of Comparative Example 1 in which the metal plating layer was not provided was light in weight, but the moisture barrier property was inferior and the electrolyte solution diffusion preventing property was also inferior. In addition, the outside of Comparative Example 2 Although the material has excellent moisture barrier properties and excellent electrolyte diffusion prevention, it cannot be made lightweight. As described above, in Comparative Examples 1 and 2, it is not possible to have both excellent moisture barrier properties, excellent electrolyte solution diffusion preventing property, and sufficient weight reduction.

Further, the amount of water after the first, second, and third weeks of the third embodiment in which the thickness of the metal plating layer was 0.5 μm was compared with the amount of water after the first, second, and third weeks of the first embodiment in which the thickness of the metal plating layer was 2 μm. It can be known that the thicker the metal plating layer, the higher the moisture shielding last name.

Further, the mass change rate after the first, second, and third weeks of the third embodiment in which the thickness of the metal plating layer was 0.5 μm, and the mass change rate after the first, second, and third weeks after the first embodiment of the metal plating layer having a thickness of 2 μm. In contrast, it can be seen that the thicker the metal plating layer, the higher the electrolyte diffusion preventing property.

[The possibility of industrial use]

The exterior material for an electrochemical device of the present invention is preferably used, for example, as an exterior material for a battery or an exterior material for a capacitor, but is not particularly limited. Among them, the exterior material for an electrochemical device of the present invention can be preferably used as an exterior material for a small electrochemical device having a capacity of 30 mA to 500 mA.

The electrochemical device of the present invention can be preferably used, for example, as follows:

1) Lithium polymer batteries, lithium ion batteries, lithium ion capacitors, and electric double layer capacitors used in portable devices such as smart phones and tablet computers

2) Power supply for hybrid vehicles, electric vehicles, etc.

3) Batteries or capacitors used for wind power generation, solar power generation, and nighttime power storage

Etc., but not limited to such uses.

The present application is a priority claim of Japanese Patent Application No. 2014-60266, filed on March 24, 2014, the disclosure of which is incorporated herein in its entirety.

The terms and descriptions used herein are for describing embodiments of the invention, but the invention is not limited thereto. Any equivalents of the features disclosed and described herein are not to be construed as limited, and various modifications within the scope of the invention are intended to be accepted.

1‧‧‧External materials for electrochemical devices

2‧‧‧Outer layer

3‧‧‧ thermoplastic resin unstretched film layer (inner layer)

4‧‧‧metal foil layer

5‧‧‧1st adhesive layer

6‧‧‧2nd adhesive layer

8‧‧‧Metal plating

10‧‧‧Shield

12‧‧‧Heat resistant resin film layer

T‧‧‧ thickness of plating

Claims (9)

An exterior material for an electrochemical device, comprising: a metal foil layer; and a thermoplastic resin unstretched film layer as an inner layer; and in the outer casing for the electrochemical device, the metal foil layer is at least A metal plating is formed on the surface of one side. An exterior material for an electrochemical device, comprising: an outer layer, a thermoplastic resin unstretched film layer as an inner layer, and a metal foil layer disposed between the outer layer and the inner layer; and the electrification In the exterior material for a device, a metal plating layer is formed on at least one surface of the metal foil layer. The exterior material for an electrochemical device according to the second aspect of the invention, wherein the outer layer is a heat resistant resin film layer. The exterior material for an electrochemical device according to the second aspect of the invention, wherein the outer layer is coated with a heat resistant resin coating layer formed of a heat resistant resin. The exterior material for an electrochemical device according to any one of claims 1 to 4, wherein the thickness of the metal foil layer is 5 μm or more and less than 30 μm. The exterior material for an electrochemical device according to any one of claims 1 to 5, wherein the metal plating layer has a thickness of 0.5 μm to 5 μm. The exterior material for an electrochemical device according to any one of the invention, wherein the metal plating layer is at least one selected from the group consisting of nickel, zinc, tin, chromium, and cobalt. A coating made of a metal material. The exterior material for an electrochemical device according to any one of claims 1 to 7, wherein the outer casing has a thickness of 30 μm to 80 μm. An electrochemical device characterized by having: An external component for an electrochemical device according to any one of the first to eighth aspects of the invention, wherein the external component of the electrochemical device is externally attached to the external component.