JP2015185340A - Outer packaging material for electrochemical device and electrochemical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an outer packaging material for an electrochemical device, capable of being sufficiently reduced in weight, capable of suppressing moisture from an outside from entering and also capable of preventing an electrolyte from being dispersed.SOLUTION: In an outer packaging material for an electrochemical device including a metal foil layer 4 and a thermoplastic resin unstretched film layer 3 serving as an inner layer, a metal plating layer 8 is formed on at least one surface of the metal foil layer 4.

Description

  The present invention relates to batteries and capacitors used for portable devices such as smartphones and tablets, hybrid vehicles, electric vehicles, wind power generation, solar power generation, and electrochemical devices such as batteries and capacitors used for power storage for night electricity. The present invention relates to a thin and lightweight exterior material and an electrochemical device that is exteriorized with the exterior material.

  In the present specification, the term “outer layer” does not mean the outermost side in the exterior material, but means that it is arranged outside the metal foil layer.

  In this specification, the term “aluminum” is used to include aluminum and alloys thereof.

  As mobile electrical devices such as smartphones and tablet terminals become thinner and lighter, the exterior materials for electrochemical devices such as lithium ion batteries, lithium polymer batteries, lithium ion capacitors, and electric double layer capacitors mounted on them are as follows: In place of the conventional metal can, weight reduction is achieved by using a laminate exterior material in which a plastic film is bonded to both surfaces of an aluminum foil. In addition, as an application thereof, power sources for electric vehicles, large-scale power sources for power storage, capacitors, and the like have been increasingly packaged with the laminate exterior material configured as described above.

  As the laminate outer packaging material, a heat-resistant stretched film is bonded to one surface of an aluminum foil serving as a barrier layer, and a heat-sealable non-stretched film that can be heat-sealed is bonded to the other surface of the aluminum foil. The combined structure is general. With such a structure, even an exterior material having a total thickness of about 100 μm has a function of preventing intrusion of moisture and various gases into the inside and an electrolyte leakage preventing function (Patent Document 1). reference). In addition, the exterior material of Example 1 of Patent Document 1 has a thickness of about 98 μm, and the exterior material of Example 2 has a thickness of about 103 μm.

JP 2002-25511 A

  By the way, in recent years, the above-mentioned mobile electrical devices and the like have been further reduced in thickness and weight, and it is required to reduce the thickness and weight of the electrochemical device mounted therein. In response, developments are being made to reduce the thickness and weight of exterior materials for electrochemical devices. At present, the exterior material is made of aluminum foil having a thickness of 30 μm or more, which is considered to have no possibility of generating pinholes. If the thickness is less than 30 μm, pinholes may be generated in the aluminum foil, and it is known that the number of pinholes increases as the thickness is reduced. When pinholes are present, the aluminum foil cannot function as a barrier layer, and therefore, it cannot prevent moisture from entering from the outside, nor can it prevent diffusion or leakage of the electrolyte. Occur.

  On the other hand, in order to eliminate pinholes in the aluminum foil, when the thickness of the aluminum foil is 30 μm or more, the total thickness as the exterior material is at least 80 μm. It was actually difficult to make it.

  For this reason, even when used as a packaging material for small electrochemical devices such as small-capacity lithium ion batteries of about 30 mA to 500 mA, in fact, large-scale electric batteries such as lithium-ion batteries with large capacities exceeding 500 mA are used. The same specification as the exterior material for the chemical device is used, and in particular, the reduction in thickness and weight of the exterior material for a small electrochemical device having a capacity of 30 mA to 500 mA has been a major issue. .

  The present invention has been made in view of such a technical background, and is capable of sufficiently reducing the weight, suppressing the intrusion of moisture from the outside, and preventing the diffusion of the electrolyte. It aims at providing the exterior material for devices.

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

[1] In an exterior device for an electrochemical device including a metal foil layer and a thermoplastic resin unstretched film layer as an inner layer,
An outer packaging material for an electrochemical device, wherein a metal plating layer is formed on at least one surface of the metal foil layer.

[2] In an exterior device 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,
An outer packaging material for an electrochemical device, wherein a metal plating layer is formed on at least one surface of the metal foil layer.

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

  [4] The outer packaging material for an electrochemical device according to [2], wherein the outer layer is a heat resistant resin coat layer formed by applying a heat resistant resin.

  [5] The packaging material for an electrochemical device according to any one of the aforementioned Items 1 to 4, wherein the thickness of the metal foil layer is 5 μm or more and less than 30 μm.

  [6] The packaging material for electrochemical devices according to any one of 1 to 5, wherein the thickness of the metal plating layer is 0.5 μm to 5 μm.

  [7] The metal plating layer according to any one of items 1 to 6, wherein the metal plating layer is a plating layer made of at least one metal material selected from the group consisting of nickel, zinc, tin, chromium, and cobalt. Exterior material for electrochemical devices.

  [8] The packaging material for electrochemical devices according to any one of 1 to 7 above, wherein the packaging material has a thickness of 30 μm to 80 μm.

[9] Electrochemical device body,
The outer packaging material for an electrochemical device according to any one of items 1 to 8,
The electrochemical device main body is covered with the exterior material.

  In the inventions of [1] and [2], since the metal plating layer is formed on at least one surface of the metal foil layer, pinholes exist in the metal foil layer due to the thinning of the metal foil. However, the metal plating layer can suppress the intrusion of moisture from the outside, and can also suppress the diffusion and leakage of the electrolyte solution to the outside. As described above, the above-described effects can be improved by the presence of the metal plating layer. Therefore, even if the thickness of the metal foil layer is designed to be thin (for example, 5 μm or more and less than 30 μm) and reduced in weight, the exterior material is externally applied. Intrusion of moisture can be suppressed, and diffusion of the electrolyte can also be prevented. Therefore, according to the present invention, it is possible to ensure excellent moisture barrier properties and excellent electrolyte solution diffusion preventing properties while achieving sufficient thinning and weight reduction. Thus, the electrochemical device packaged using the packaging material of the present invention that has been reduced in thickness and weight can improve the weight energy density and volume energy density of the electrochemical device. Furthermore, since the metal plating layer is formed on at least one surface of the metal foil layer, the puncture resistance of the metal foil itself can be further improved.

  Furthermore, in the invention of [2], since the outer layer is provided, a sufficient puncture strength as an exterior material can be secured, and the puncture resistance can be improved.

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

  In the invention of [4], since the outer layer is a heat-resistant resin coat layer formed by applying a heat-resistant resin, the puncture strength can be further improved as an exterior material. Further, the heat-resistant resin coat layer can be made thinner than the case where the outer layer is constituted by the heat-resistant resin film layer.

  In the invention of [5], since the thickness of the metal foil layer is 5 μm or more and less than 30 μm, it is possible to further reduce the thickness and weight while ensuring excellent moisture barrier properties and excellent electrolyte solution diffusion preventing properties. it can.

  In the invention of [6], since the thickness of the metal plating layer is 0.5 μm to 5 μm, it is possible to ensure an excellent moisture barrier property and an excellent electrolyte solution diffusion preventing property while sufficiently reducing the thickness and weight. .

  In the invention of [7], the metal plating layer is a plating layer made of at least one metal material selected from the group consisting of nickel, zinc, tin, chromium, and cobalt, so that the moisture barrier property is further improved. In addition, it is possible to ensure even better electrolyte diffusion prevention properties and to further improve the puncture strength as an exterior material.

  In the invention of [8], since the thickness of the packaging material is 30 μm to 80 μm, the electrochemical device packaged using this packaging material further improves the weight energy density and volumetric energy density of the electrochemical device. Can do.

  [9] The invention (electrochemical device) provides an electrochemical device that can ensure excellent moisture barrier properties and excellent electrolyte diffusion prevention properties, as well as improved weight energy density and volume energy density, by the exterior material. Is done.

It is sectional drawing which shows one Embodiment (1st Embodiment) of the exterior material for electrochemical devices of this invention. It is sectional drawing which shows other embodiment (2nd Embodiment) of the exterior material for electrochemical devices of this invention. It is sectional drawing which shows other embodiment (3rd Embodiment) of the exterior material for electrochemical devices of this invention. It is sectional drawing which shows other embodiment (4th Embodiment) of the exterior material for electrochemical devices of this invention. It is sectional drawing which shows one Embodiment of the electrochemical device of this invention. It is a perspective view shown in the separated state before heat-sealing the exterior material (planar thing) which comprises the electrochemical device of FIG. 5, the electrochemical device main-body part, and the exterior material (thing shape | molded in the solid shape). .

  One embodiment of the outer packaging material 1 for an electrochemical device according to the present invention is shown in FIG. In this outer packaging material 1 for electrochemical devices, an outer layer 2 is laminated on one side of a barrier layer 10 having metal plating layers 8 and 8 formed on both sides of a metal foil layer 4 via a first adhesive layer 5. The thermoplastic resin unstretched film layer (inner layer) 3 is laminated and integrated on the other surface of the barrier layer 10 via the second adhesive layer 6. In the present embodiment, the outer layer 2 is composed of a heat resistant resin film layer 12.

  In the embodiment shown in FIG. 1, the barrier layer 10 is formed by forming metal plating layers 8 and 8 on both surfaces of the metal foil layer 4, but is not particularly limited to such a configuration. As shown in FIGS. 2 and 3, a configuration in which the metal plating layer 8 is formed only on one surface of the metal foil layer 4 may be adopted.

  That is, in the embodiment shown in FIG. 2, the packaging material 1 for an electrochemical device is formed on the one surface of the barrier layer 10 in which the metal plating layer 8 is formed on one surface of the metal foil layer 4 (the metal plating layer). The outer layer 2 is laminated and integrated via the first adhesive layer 5 (on the surface of 8), and the second adhesive layer 6 is formed on the other surface of the barrier layer 10 (on the surface of the metal foil layer 4). The thermoplastic resin unstretched film layer (inner layer) 3 is laminated and integrated. In this embodiment, the outer layer 2 is composed of a heat resistant resin film layer 12.

  In the embodiment shown in FIG. 3, the packaging material 1 for an electrochemical device is formed on the other surface of the barrier layer 10 in which the metal plating layer 8 is formed on one surface of the metal foil layer 4 (the metal foil layer 4 The outer layer 2 is laminated and integrated via the first adhesive layer 5 on the surface of the barrier layer 10 and the second adhesive layer 6 is provided on one surface of the barrier layer 10 (on the surface of the metal plating layer 8). The thermoplastic resin unstretched film layer (inner layer) 3 is laminated and integrated. In this embodiment, the outer layer 2 is composed of a heat resistant resin film layer 12.

  On the other hand, in the embodiment shown in FIG. 4, the outer packaging material 1 for an electrochemical device is formed as an outer layer 2 on one surface of a barrier layer 10 in which metal plating layers 8 and 8 are formed on both surfaces of a metal foil layer 4. The heat-resistant resin coat layer 13 is laminated and integrated, and the thermoplastic resin unstretched film layer (inner layer) 3 is laminated and integrated on the other surface of the barrier layer 10 via the second adhesive layer 6. Consisting of

  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 pinholes exist in the metal foil layer 4 due to the thinning of the metal foil. It is considered that the end opening in the pinhole depth direction (metal foil thickness direction) is substantially closed by the metal plating layer 8. Further, the plated portion of the metal plating layer 8 may enter and close or close to the inside of the pinhole in the metal foil layer 4 (region entering the inside of the hole further from the end opening in the pinhole). It is considered a thing.

  In the electrochemical device exterior material 1, since the metal plating layer 8 is formed on at least one surface of the metal foil layer 4, there is a pinhole in the metal foil layer 4 by thinning the metal foil. Even so, the metal plating layer 4 can suppress the intrusion of moisture from the outside, and can also suppress the diffusion and leakage of the electrolyte to the outside. Since the various effects can be improved by the presence of the metal plating layer 4 as described above, even if the thickness of the metal foil layer 4 is designed thin (for example, 5 μm or more and less than 30 μm) to reduce the weight, the exterior material 1 As a result, intrusion of moisture from the outside can be suppressed and diffusion of the electrolyte can also be prevented. Therefore, according to the present invention, it is possible to ensure excellent moisture barrier properties and excellent electrolyte solution diffusion preventing properties while achieving sufficient thinning and weight reduction. Thus, the electrochemical device 30 packaged using the packaging material 1 of the present invention that has been thinned and reduced in weight can improve the weight energy density and volume energy density of the electrochemical device. Furthermore, since the metal plating layer 8 is formed on at least one surface of the metal foil layer 4, the puncture resistance of the metal foil itself can be further improved.

  Furthermore, in the embodiment shown in FIGS. 1 to 4, since the outer layer 2 is provided, sufficient puncture strength can be secured as the exterior material 1 and puncture resistance can be sufficiently improved.

  1 and 4, the metal foil layer 4, the metal plating layer 8 formed on one surface of the metal foil layer 4, and the other of the metal foil layer 4 are assumed to function as a barrier. 3, there are three layers of the metal plating layer 8 formed on the surface of FIG. 2, the laminated structure shown in FIGS. 2 and 3 (the one that functions as a barrier is the metal foil layer 4, one surface of the metal foil layer 4. Compared with the two layers of the metal plating layer 8 formed in the above, there is an advantage that a better moisture barrier property and a better electrolyte solution diffusion preventing property can be secured.

  In the present invention, when the thickness of the metal foil layer 4 is set to be less than 30 μm in order to reduce the weight sufficiently, there is a possibility that pinholes are generated in the metal foil. Although the layer 8 cannot be denied that a part of the layer 8 may be peeled off due to a stress change or the like, the configuration of FIGS. 2 and 3 (a configuration in which a double barrier of the metal foil layer 4 and one metal plating layer 8 is provided) ), The pinhole position (specific point) of the metal foil layer 4 and the peeling point position (specific point) of the metal plating layer 8 are not substantially overlapped. Performance and excellent electrolytic solution diffusion prevention can be ensured.

  1 and 4, the metal foil layer 4, the metal plating layer 8 formed on one surface of the metal foil layer 4, and the metal plating layer formed on the other surface of the metal foil layer 4. 8 is provided with a triple barrier portion, the pinhole position (specific point) of the metal foil layer 4, the peeling point (specific point) of the one metal plating layer 8, and the other metal plating layer 8. Since there is virtually no possibility that all three peeling points (specific points) overlap at the same position, in the configuration in which these three barrier portions are provided (configuration in FIGS. 1 and 4), FIG. Compared with the configurations of 2 and 3 (a configuration in which a double barrier portion is provided), it is possible to ensure a better moisture barrier property and a better electrolyte solution diffusion preventing property.

  In the present invention, the metal foil layer 4 plays a role of providing the exterior material 1 with a gas barrier property that prevents oxygen and moisture from entering. The thickness of the metal foil layer 4 is preferably 5 μm or more and less than 30 μm. By making this thickness range, it is possible to reduce the thickness and weight, and by adjusting the thickness of the metal plating layer 8 to increase or decrease, the exterior material 1 as a whole has an excellent moisture barrier property and an excellent electrolyte solution. Diffusion prevention can be ensured. Among these, 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. Although it does not specifically limit as said metal foil, For example, aluminum foil, stainless steel foil, nickel foil, copper foil, titanium foil etc. are mentioned. Among them, it is preferable to use an aluminum foil 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 resin, and although there are a very small amount of these resin layers, there is a possibility that light, oxygen, and liquid enter from the outside of the case. Yes, the contents (battery electrolyte, food, pharmaceuticals, etc.) may penetrate from the inside. When these intruders reach the metal foil layer 4, they cause corrosion of the metal foil layer. In the present invention, it is preferable that a chemical conversion film is formed at least on the surface of the metal foil on the thermoplastic resin layer 3 side. In this case, the corrosion resistance of the metal foil layer 4 can be improved. Among these, it is particularly preferable to adopt a configuration in which a chemical conversion film is formed on both surfaces of the metal foil. 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, and can be formed, for example, by subjecting the metal foil to a chromate treatment or a non-chromium chemical conversion treatment using a zirconium compound. For example, in the case of chromate treatment, an aqueous solution of any one of the following 1) to 3) is applied to the surface of the metal foil that has been degreased and then dried.
1) An aqueous solution of a mixture containing phosphoric acid, chromic acid, and at least one compound selected from the group consisting of a fluoride metal salt and a fluoride non-metal salt 2) phosphoric acid, an acrylic resin, An aqueous solution of a mixture comprising at least one resin selected from the group consisting of chitosan derivative resins and phenolic resins, and at least one compound selected from the group consisting of chromic acid and chromium (III) salts 3) phosphoric acid And at least one resin selected from the group consisting of acrylic resins, chitosan derivative resins and phenolic resins, at least one compound selected from the group consisting of chromic acid and chromium (III) salts, and fluoride An aqueous solution of a mixture comprising at least one compound selected from the group consisting of a metal salt and a non-metal salt of fluoride.

The conversion coating, chromium coating weight preferably is 0.1mg / m ² ~50mg / m ² as a (per one surface), in particular 2mg / m ² ~20mg / m 2 preferred.

  Although the metal which comprises the said metal plating layer 8 is not specifically limited, For example, nickel, zinc, tin, chromium, cobalt, gold | metal | money, silver, platinum etc. are mentioned. Among these, the metal plating layer 8 is preferably a plating layer made of at least one metal material selected from the group consisting of nickel, zinc, tin, chromium and cobalt, and at least one of these specific metal materials. In the case of being constituted by seeds, it is possible to ensure a further excellent moisture barrier property and a further excellent electrolytic solution diffusion preventing property and to further improve the puncture strength as the exterior material 1.

  The thickness T of the metal plating layer 8 (the thickness of the plating layer formed on one side when the plating layer is formed on both sides) T is preferably set to 0.5 μm to 5 μm. If the thickness of the metal foil layer 4 is less than 30 μm, pinholes may occur in the metal foil, but the thickness T of the metal plating layer 8 is adjusted to increase or decrease in accordance with the thickness of the metal foil. Thus, it is possible to ensure the excellent moisture barrier property and the excellent electrolyte solution diffusion preventing property as the exterior material 1 as a whole. Among these, the thickness T of the metal plating layer 8 (the thickness of the plating layer formed on one side when the plating layers are formed on both sides) T is from the viewpoint of sufficiently closing the pinhole of the metal foil layer 4. It is more preferable to set to 2 micrometers-5 micrometers (refer FIGS. 1-4). In addition, when nickel is used as the metal constituting the metal plating layer 8, there is an advantage that the piercing strength can be further improved as compared with the case where other metal is used.

  The metal plating method is not particularly limited, and examples thereof include an electroless plating method, an electroplating method, and a vacuum plating method. Among these, the metal plating layer 8 is preferably formed by an electroless plating method. Compared with the electroplating method, the metal plating layer formed by the electroless plating method has a more uniform plating layer with no unevenness, and has excellent moisture barrier properties and excellent electrolyte solution diffusion prevention properties. In particular, when the metal foil layer 4 is an aluminum foil layer, the metal plating layer (metal plating layer formed by an electroless plating method) 8 has high adhesion to the aluminum foil layer 4. There is an advantageous effect that.

  The thermoplastic resin unstretched film layer (inner layer) 3 has excellent chemical resistance against highly corrosive electrolytes used in lithium ion secondary batteries and the like, and heat seals the exterior material. It plays a role of imparting sex.

  Although it does not specifically limit as resin which comprises the said thermoplastic resin unstretched film layer 3, For example, polyethylene, a polypropylene, an ionomer, ethylene ethyl acrylate (EEA), ethylene methyl acrylate (EAA), ethylene Examples thereof include methyl methacrylate resin (EMMA), ethylene-vinyl acetate copolymer resin (EVA), maleic anhydride-modified polypropylene, and maleic anhydride-modified polyethylene.

  The thickness of the unstretched thermoplastic resin film layer 3 is preferably set to 20 μm to 80 μm. When the thickness is 20 μm or more, pinholes can be sufficiently prevented from being generated, and by setting the thickness to 80 μm or less, the amount of resin used can be reduced, and the cost can be reduced. Especially, it is especially preferable that the thickness of the unstretched thermoplastic resin film layer 3 is set to 30 μm to 50 μm. The unstretched thermoplastic resin film layer 3 may be a single layer or a multilayer.

  In the present invention, the outer layer 2 is a member that mainly plays a role of ensuring good formability as an exterior material, that is, plays a role of preventing breakage due to necking of the metal foil during forming. In the present invention, the outer layer 2 is not an essential constituent layer, but is preferably provided.

  The outer layer 2 is not particularly limited, but is composed of a heat resistant resin film layer 12 or a heat resistant resin coat layer 13 formed by applying a heat resistant resin. Is preferred. In this case, there is an advantage that the piercing strength can be further improved as the exterior material 1.

  Although it does not specifically limit as the said heat resistant resin film layer 12, For example, a stretched polyamide film (stretched nylon film etc.) and a stretched polyester film are used preferably. Among them, the heat-resistant resin film layer 12 includes a biaxially stretched polyamide film (biaxially stretched nylon film, etc.), a biaxially stretched polybutylene terephthalate (PBT) film, a biaxially stretched polyethylene terephthalate (PET) film, or a biaxially stretched film. It is particularly preferable that the film is composed of a polyethylene naphthalate (PEN) film. Although it does not specifically limit as said nylon, For example, 6 nylon, 6, 6 nylon, MXD nylon etc. are mentioned. The heat-resistant resin film layer 12 may be formed as a single layer (single stretched film), or a multi-layer (biaxially stretched PET film / It may be formed of a bilayer stretched nylon film or the like.

  Among them, the heat resistant resin film layer 12 has a multilayer structure including a biaxially stretched polyester film disposed on the outer side and a biaxially stretched polyamide film disposed on the first adhesive layer 5 side. Is preferred. Furthermore, the heat resistant resin film layer 12 has a multilayer structure including a biaxially stretched polyethylene terephthalate film disposed on the outer side and a biaxially stretched nylon film disposed on the first adhesive layer 5 side. Is more preferable.

  In addition, the said heat resistant resin film layer 12 may be comprised with heat resistant resin unstretched films, such as a polycarbonate unstretched film and 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 coat layer 13 is a coat 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. Or it can form by apply | coating to this one side of the barrier layer 10 in which the metal plating layer 8 is formed in at least one surface of the metal foil layer 4 (on the surface of the metal plating layer 8).

  The heat resistant resin constituting the heat resistant resin coat layer 13 is not particularly limited, and examples thereof include acrylic resins, epoxy resins, urethane resins, polyolefin resins, and fluorine resins. . Among them, it is preferable to use a fluororesin based on tetrafluoroethylene or fluoroethylene vinyl ether in terms of excellent heat resistance and chemical resistance. Furthermore, additives such as fine particles (silica, acrylic beads, etc.) and ink may be added to the heat-resistant resin in order to improve the design by changing the appearance of the exterior material.

  The method for the resin coating 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 coat layer 13 is preferably set to 0.1 μm to 40 μm. Especially, it is more preferable that the thickness of the heat-resistant resin coat layer 13 is set to 0.1 μm to 20 μm.

  It is good also as a structure which laminated | stacked the vapor deposition layer on the outer surface and / or inner surface (surface by the side of the metal foil layer 4) of the said outer side layer 2. FIG. By providing such a vapor deposition layer, it is possible to secure a further excellent moisture barrier property and a further excellent electrolyte solution diffusion preventing property. It is preferable that the vapor deposition layer is composed of at least one material selected from the group consisting of metals, metal oxides, and fluorides. Although it does not specifically limit as said metal, For example, aluminum, chromium, zinc, nickel, gold | metal | money, silver, platinum etc. are mentioned. The metal oxide is not particularly limited, and examples thereof include alumina, silica, titanium oxide, and zirconium oxide. Although it does not specifically limit as said fluoride, For example, magnesium fluoride etc. are mentioned. Especially, it is especially preferable that the material (vapor deposition material) for forming the vapor deposition layer is at least one material selected from the group consisting of aluminum, alumina, and silica.

  The first adhesive layer 5 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 first adhesive layer 5 is preferably set to 1 μm to 5 μm. Especially, it is especially preferable that the thickness of the said 1st adhesive bond layer 5 is set to 1 micrometer-3 micrometers from a viewpoint of thickness reduction of an exterior material and weight reduction.

  Although it does not specifically limit as said 2nd adhesive bond layer 6, For example, what was illustrated as said 1st adhesive bond layer 5 can be used, However, The polyolefin-type adhesive agent with few swelling by electrolyte solution is used. Is preferred. The thickness of the second adhesive layer 6 is preferably set to 1 μm to 5 μm. Especially, it is especially preferable that the thickness of the said 2nd adhesive bond layer 6 is set to 1 micrometer-3 micrometers from a viewpoint of thickness reduction of an exterior material and weight reduction.

  The barrier layer 10 (barrier layer 10 having a metal plating layer 8 formed on at least one surface of the metal foil layer 4) and the outer layer 2 (heat-resistant resin film layer 12, heat-resistant resin coat layer 13). Etc.) is not particularly limited, but a method called dry lamination can be recommended. Specifically, after the prepared first adhesive is applied to the upper surface of the barrier layer 10, the lower surface of the outer layer 2, or both of these surfaces, the solvent is evaporated to form a dry film, The outer layer 2 is bonded together. Thereafter, curing is performed according to the curing conditions of the first adhesive. Thereby, the barrier layer 10 and the outer layer 2 are bonded via the first adhesive layer 5. Examples of the method for applying the first adhesive include a gravure coating method, a reverse roll coating method, and a lip roll coating method.

  The bonding method of the barrier layer 10 (the barrier layer 10 having the metal plating layer 8 formed on at least one surface of the metal foil layer 4) and the thermoplastic resin unstretched film layer 3 is particularly limited. However, similar to the above-described bonding between the barrier layer 10 and the outer layer 2, the second adhesive is applied and dried, and then the barrier layer 10 and the thermoplastic resin unstretched film layer 3 are bonded together. A laminating method can be illustrated.

  The thermoplastic resin layer 3 and the outer layer 2 may contain an additive. Examples of such additives include, but are not limited to, antiblocking agents (silica, talc, kaolin, acrylic resin beads, etc.), lubricants (fatty acid amide, wax, etc.), antioxidants (hindered) Phenol, etc.).

  The thickness of the packaging material 1 of the present invention is preferably set to 30 μm to 80 μm. By being 80 micrometers or less, the weight energy density and volume energy density of the electrochemical device 30 armored using this exterior material 1 can be improved. Especially, it is more preferable that the thickness of the exterior material 1 is set to 30 μm to 65 μm.

  In the exterior material 1 of the present invention, the outer layer 2 is not an essential constituent layer, but the barrier layer 10 (the barrier layer 10 in which the metal plating layer 8 is formed on at least one surface of the metal foil layer 4). A structure in which the thermoplastic resin unstretched film layer (inner layer) 3 is laminated and integrated on one surface of the second adhesive layer 6 may be employed.

  Moreover, in the said embodiment, although the structure which provided the 1st adhesive bond layer 5 and the 2nd adhesive bond layer 6 is employ | adopted, these both layers 5 and 6 are not an essential structural layer, These are these. It is also possible to adopt a configuration that is not provided.

  Moreover, the exterior material 1 of this invention is not specifically limited to the laminated structure shown in FIGS. 1-4, It can also add a layer and can improve a function as an exterior material.

  A molding case (battery case or the like) for an electrochemical device can be obtained by molding the outer packaging material 1 of the present invention (deep drawing molding, stretch molding or the like).

  Next, one embodiment of the electrochemical device 30 of the present invention is shown in FIGS. As shown in FIGS. 5 and 6, a substantially rectangular parallelepiped electrochemical device body (electrochemical element) 31 is accommodated in the accommodating recess of the molding case 1 </ b> A obtained by molding the exterior material 1 of the present invention, On the electrochemical device main body 31, the outer packaging material 1 of the present invention is disposed with the inner layer 3 side inward (lower side), and the peripheral portion of the inner layer 3 of the planar outer packaging material 1, The electrochemical device 30 of the present invention is configured by sealing and sealing the inner layer 3 of the flange portion (sealing peripheral portion) 29 of the molded case 1A by heat sealing.

  In FIG. 5, 39 is a heat seal part where the peripheral part of the exterior material 1 and the flange part (sealing peripheral part) 29 of the molded case 1A are joined (welded).

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

  The width of the heat seal part 39 is preferably set to 0.5 mm or more. Sealing can be reliably performed by setting it as 0.5 mm or more. Especially, it is preferable to set the width | variety of the said heat seal part 39 to 3 mm-15 mm.

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

<Example 1>
By performing electroless nickel plating (Kanizen plating) on a soft aluminum foil (A8079 soft aluminum alloy foil defined by JIS H4000) 4 having a thickness of 15 μm, each of both surfaces of the soft aluminum foil 4 has a thickness (T). A nickel plating layer 8 having a thickness of 2 μm was formed to obtain a double-sided plated aluminum foil (barrier layer 10) having a thickness of 19 μm.

Next, after applying a chemical conversion treatment solution composed of phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water, and alcohol on both sides of the double-sided plated aluminum foil (barrier layer 10), 150 A double-sided plated aluminum foil having a chemical conversion film formed on both sides was prepared by drying at 0 ° C. The amount of chromium deposited by this chemical film was 5 mg / m ^{2 on} one side.

  Next, a two-component curable polyester-urethane resin adhesive is applied to one side of the double-sided plated aluminum foil having a chemical conversion film formed on both sides, and dried to form the first adhesive layer 5; A biaxially stretched polyester film 2 having a thickness of 12 μm is bonded to the surface of the first adhesive layer 5, and a two-component curable polyolefin-based adhesive (acid-modified polypropylene is used as a main component and hexamethylene is formed on the other surface of the aluminum foil. A two-component curable adhesive having a diisocyanate as a curing agent) is applied and dried to form a second adhesive layer 6, and an unstretched polypropylene film 3 having a thickness of 25 μm is pasted on the surface of the second adhesive layer 6. Combined. The laminated body was allowed to stand for 3 days in an environment of 40 ° C. (curing was performed) to obtain an outer packaging material for electrochemical devices (thickness 62 μm) 1 shown in FIG.

<Example 2>
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. Got.

<Example 3>
1 was obtained in the same manner as in Example 1 except that the thickness T of the nickel plating layer 8 was changed to 0.5 μm. The outer packaging material for electrochemical devices (thickness 59 μm) 1 shown in FIG.

<Example 4>
As a double-sided plated aluminum foil, electroless nickel plating (Kanizen plating) is performed on a soft aluminum foil (A8079 soft aluminum alloy foil defined by JIS H4000) 4 having a thickness of 15 μm, and each of the soft aluminum foils has a thickness. After forming a 1 μm nickel plating layer, electroless tin plating was performed, and a 19 μm thick double-sided plated aluminum foil obtained by laminating a 1 μm thick tin plating layer on each of the two surfaces was used. In the same manner as in Example 1, the outer packaging material for electrochemical devices (thickness 62 μm) 1 shown in FIG. 1 was obtained.

<Example 5>
The electric circuit shown in FIG. 2 is the same as in Example 1 except that instead of the double-sided plated aluminum foil, a single-sided plated aluminum foil in which a nickel plating layer 8 having a thickness of 2 μm is formed on one side of a soft aluminum foil is used. A packaging material for chemical devices (thickness 60 μm) 1 was obtained. In addition, the biaxially stretched polyester film 2 was bonded to the plated surface 8 side of the single-sided plated aluminum foil (see FIG. 2).

<Example 6>
A copolymer of tetrafluoroethylene and vinyl acetate is used as a main resin, and a mixture of tolylene diisocyanate (TDI) and hexamethylene diisocyanate (HDI) so as to have a mass ratio of 1: 1 is used as a curing agent. 100 parts by mass of resin and 18 parts by mass of the curing agent were mixed to obtain a coat resin (heat resistant resin).

  Next, ethyl acetate is added as a solvent to a resin composition obtained by mixing 80 parts by mass of the coating resin (heat resistant resin), 10 parts by mass of barium sulfate, and 10 parts by mass of granular silica, so that the solid content becomes 19% by mass. A resin solution prepared as described above was prepared.

  Next, by applying the resin solution to the one surface of the double-sided plated aluminum foil (surface of the plating layer 8) on which the chemical conversion film was formed on both surfaces obtained in Example 1 by the gravure roll method, and then drying, While laminating a heat-resistant resin coating layer 13 having a thickness of 2 μm after drying, a two-component curable polyolefin adhesive (based on acid-modified polypropylene) on the other surface of the aluminum foil (surface of the plating layer 8), A two-component curable adhesive having hexamethylene diisocyanate as a curing agent) is applied and dried to form a second adhesive layer 6, and an unstretched polypropylene film 3 having a thickness of 25 μm is formed on the surface of the second adhesive layer 6. Were pasted together. The laminated body was allowed to stand for 3 days in an environment of 40 ° C. (curing was performed), thereby obtaining an outer packaging material for electrochemical devices (thickness 50 μm) 1 shown in FIG.

<Comparative Example 1>
For electrochemical devices 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 defined by JIS H4000) was used instead of the double-sided plated aluminum foil having a thickness of 19 μm. An exterior material was obtained.

<Comparative Example 2>
For electrochemical devices in the same manner as in Example 1, except that a 40 μm thick soft aluminum foil (A8079 soft aluminum alloy foil defined in JIS H4000) was used instead of the 19 μm thick double-sided plated aluminum foil An exterior material was obtained.

上記のようにして得られた各電気化学デバイス用外装材を用いて下記のとおり電池（模擬電池）を作成した。まず、外装材を縦１２０ｍｍ×横１００ｍｍの大きさに裁断し、この裁断した外装材を、雄型と雌型からなる金型を用いて、縦１００ｍｍ×横８０ｍｍ×深さ２ｍｍの上面が開放された略直方体形状にエンボス成形することによって、周囲にフランジ部２９を有する成形ケース１Ａを作成した（図６参照）。なお、上面が開放された略直方体形状の底面の内面が未延伸ポリプロピレンフィルム（内側層）３になるようにエンボス成形した。一方、エンボス成形を施さない縦１２０ｍｍ×横１００ｍｍの大きさの外装材１の裁断品（以下、「平面状外装材」という）も作成した（図６参照）。

A battery (simulated battery) was prepared as follows using each of the packaging materials for electrochemical devices obtained as described above. First, the exterior material is cut into a size of 120 mm in length and 100 mm in width, and this cut exterior material is opened using a mold composed of a male mold and a female mold, and an upper surface of 100 mm in length, 80 mm in width, and 2 mm in depth is opened. The molded case 1A having a flange portion 29 around the periphery was created by embossing into a substantially rectangular parallelepiped shape (see FIG. 6). In addition, it emboss-molded so that the inner surface of the bottom face of the substantially rectangular parallelepiped shape with the upper surface opened could be an unstretched polypropylene film (inner layer) 3. On the other hand, a cut product (hereinafter referred to as “planar exterior material”) of the exterior material 1 having a size of 120 mm in length × 100 mm in width without embossing was also created (see FIG. 6).

  A simulated electrode in which 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 are stacked in layers and punched into a size of 95 mm in length and 75 mm in width is formed. The sheets were laminated to obtain an electrochemical device body (simulated product) 31 (see FIG. 6).

  Then, as shown in FIG. 5, after the electrochemical device body 31 is loaded into the substantially rectangular parallelepiped embossed portion of the molded case 1 </ b> A, the molded case 1 </ b> A and the planar exterior material 1 are The inner layer 3 is overlapped so that the inner layers 3 face each other, and the peripheral portion of the inner layer 3 of the planar exterior material 1 and the inner layer 3 of the flange portion 29 of the molded case 1A are out of the four sides. After heat seal joining was performed by applying a metal hot plate heated to 200 ° C. on three sides at a pressure of 0.3 MPa for 3 seconds to form a heat seal portion 39, this was placed in a dry room having a dew point of −60 ° C. Left for 24 hours.

Next, in a dry room having a dew point of −60 ° C., an electrolytic solution (ethylene carbonate: dimethylene carbonate: dimethyl carbonate is formed through an open portion on one side of the heat-sealed joined body that has not yet been joined). 10 mL of LiPF ₆ concentration obtained by adding LiPF ₆ to a mixed carbonate mixed at a volume ratio of 1: 1: 1 was injected into the interior, and then dropped to 0.086 MPa. Sealing is completed by applying a heat seal joint by applying a metal hot plate heated to 200 ° C. at a pressure of 0.3 MPa for 3 seconds to one unbonded side of the heat seal assembly in a reduced pressure state. Thus, a battery (simulated battery) 30 shown in FIG. 5 was obtained.

  For the battery (simulated battery) obtained as described above, based on the following evaluation test method, evaluate the moisture barrier property by measuring the amount of water in the electrolyte solution inside the simulated battery, and evaluate the electrolyte diffusion prevention property. went. These results are shown in Tables 2 and 3.

<Evaluation test method for moisture barrier properties>
Nine samples (simulated batteries) were prepared for each example and each comparative example, a first constant temperature and humidity chamber having a temperature of 40 ° C. and a humidity of 90%, and a second constant temperature and humidity chamber having a temperature of 60 ° C. and a humidity of 90%. , 80 ° C, 90% humidity in a third constant temperature and humidity chamber, 3 each, take out after 1 week, take out after 2 weeks, take out after 3 weeks, take out one after 3 weeks, syringe for each 1 mL of the electrolyte solution in the battery was taken out using the Karl Fischer moisture meter (“AQ2250” manufactured by Hiranuma Sangyo Co., Ltd.) and the amount of water in the electrolyte solution was measured.

  In the results shown in Table 2, the moisture content after one week has clearly increased compared to the initial moisture content (before the start of the test). It is considered that the moisture contained in a small amount in the polypropylene film was eluted into the electrolyte. From the comparison with the result of Comparative Example 1 (the amount of water after 1, 2, 3 weeks), the simulated battery constructed using the exterior material of Examples 1 to 5 has an extreme (substantial) increase in water. Was not observed, and the excellent effect of the moisture barrier by the exterior material of the present invention could be confirmed.

<Evaluation test method for electrolyte diffusion prevention>
Three samples (simulated batteries) were prepared for each example and each comparative example, and each mass (hereinafter referred to as “initial mass”) was measured with an electronic balance. Next, each sample was placed in a polypropylene tray and placed in a 40 ° C. first thermostat, a 60 ° C. second thermostat, and an 80 ° C. third thermostat, respectively. After taking out after a week and performing mass measurement, it returned to the said thermostat immediately. Mass measurement was performed in the same manner after 2 weeks and after 3 weeks. At this time, the mass decreases as the electrolyte solution diffuses and escapes, and there is no change in mass when the electrolyte solution does not escape.

X = {(mass after one week) − (initial mass)} ÷ (initial mass) × 100
Y = {(mass after 2 weeks) − (initial mass)} ÷ (initial mass) × 100
Z = {(mass after 3 weeks) − (initial mass)} ÷ (initial mass) × 100
The mass change rate X (%) after 1 week passed, the mass change rate Y (%) after 2 weeks passed, and the mass change rate Z (%) after 3 weeks passed, respectively, were calculated by the above formulas.

  As is clear from Tables 1 to 3, the battery (simulated battery) configured using the outer packaging material for electrochemical devices of Examples 1 to 6 according to the present invention is Comparative Example 1 in which no metal plating layer is provided. Compared with the exterior material, the thickness of the exterior material was the same (light weight), but the moisture barrier property was excellent and the electrolyte solution diffusion prevention property was also excellent. That is, in the battery (simulated battery) configured using the outer packaging material for electrochemical devices of Examples 1 to 6 according to the present invention, it has excellent moisture barrier property, excellent electrolyte solution diffusion preventing property, and sufficient lightness. I was able to satisfy three at the same time.

  On the other hand, although the exterior material of Comparative Example 1 in which the metal plating layer was not provided was reduced in weight, it was inferior in the moisture barrier property and inferior in the ability to diffuse the electrolytic solution. In addition, the exterior material of Comparative Example 2 was excellent in moisture barrier properties and excellent in prevention of electrolyte diffusion, but was not reduced in weight. Thus, in Comparative Examples 1 and 2, it was not possible to satisfy three of excellent moisture barrier properties, excellent electrolyte solution diffusion preventing properties, and sufficient lightness at the same time.

  It should be noted that the amount of water after 1, 2, and 3 weeks of Example 3 in which the thickness of the metal plating layer is 0.5 μm, and 1, 2, and 3 in Example 1 in which the thickness of the metal plating layer is 2 μm. From the comparison with the amount of water after a lapse of a week, it is understood that the moisture barrier property is further improved as the thickness of the metal plating layer is increased.

  Further, the mass change rate after 1, 2, and 3 weeks of Example 3 in which the thickness of the metal plating layer is 0.5 μm, and 1, 2 in Example 1 in which the thickness of the metal plating layer is 2 μm, From the comparison with the rate of mass change after the lapse of 3 weeks, it can be seen that as the thickness of the metal plating layer increases, the electrolytic solution diffusion preventing property is further improved.

  The outer packaging material for electrochemical devices according to the present invention is suitably used as, for example, a battery outer packaging material and a capacitor outer packaging material, but is not particularly limited to such applications. Among these, the packaging material for electrochemical devices according to the present invention is suitable as a packaging material for small electrochemical devices having a capacity of 30 mA to 500 mA.

The electrochemical device according to the present invention is, for example,
1) Lithium polymer batteries, lithium ion batteries, lithium ion capacitors, electric double layer capacitors used for mobile devices such as smartphones and tablets 2) Power sources for hybrid cars, electric cars, etc. 3) Wind power generation, solar power generation, nighttime electricity However, it is not particularly limited to such applications.

DESCRIPTION OF SYMBOLS 1 ... Electrochemical device exterior material 2 ... Outer layer 3 ... Thermoplastic resin unstretched film layer (inner layer)
DESCRIPTION OF SYMBOLS 4 ... Metal foil layer 5 ... 1st adhesive bond layer 6 ... 2nd adhesive bond layer 8 ... Metal plating layer 10 ... Barrier layer 12 ... Heat resistant resin film layer 13 ... Heat resistant resin coat layer 30 ... Electrochemical device 31 ... Electricity Chemical device body (electrochemical element)
T: Thickness of plating layer

Claims (9)

In an exterior device for an electrochemical device including a metal foil layer and a thermoplastic resin unstretched film layer as an inner layer,
An outer packaging material for an electrochemical device, wherein a metal plating layer is formed on at least one surface of the metal foil layer. In an exterior device 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,
An outer packaging material for an electrochemical device, wherein a metal plating layer is formed on at least one surface of the metal foil layer.   The exterior material for electrochemical devices according to claim 2, wherein the outer layer is a heat-resistant resin film layer.   The exterior device for an electrochemical device according to claim 2, wherein the outer layer is a heat-resistant resin coat layer formed by applying a heat-resistant resin.   The exterior material for electrochemical devices according to any one of claims 1 to 4, wherein the metal foil layer has a thickness of 5 µm or more and less than 30 µm.   The packaging material for an electrochemical device according to any one of claims 1 to 5, wherein a thickness of the metal plating layer is 0.5 µm to 5 µm.   The electrochemical according to any one of claims 1 to 6, wherein the metal plating layer is a plating layer made of at least one metal material selected from the group consisting of nickel, zinc, tin, chromium, and cobalt. Device exterior materials.   The thickness of the said exterior material is 30 micrometers-80 micrometers, The exterior material for electrochemical devices of any one of Claims 1-7. An electrochemical device body,
The exterior material for electrochemical devices according to any one of claims 1 to 8,
The electrochemical device main body is covered with the exterior material.

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