Adhesive, exterior material for power storage device, exterior case for power storage device, and power storage device

Abstract

The invention relates to an adhesive, an exterior material for a power storage device, an exterior case for a power storage device, and a power storage device. The present invention addresses the problem of providing an adhesive capable of producing an exterior material for a power storage device having good moldability. The adhesive contains an adhesive component, has a shear adhesive strength of 0.7 MPa or more, and is used in the formation of an adhesive layer between a base material layer and a barrier layer when an exterior material for an electricity storage device is produced.

Description

Technical Field

[0001] The present invention relates to an adhesive, an exterior material for an electric storage device, an exterior case for an electric storage device, and an electric storage device. Background Art

[0002] In recent years, with the thinning and lightening of mobile electric devices such as smartphones and tablet terminals, as an exterior material for electric storage devices such as lithium ion secondary batteries, lithium polymer secondary batteries, lithium ion electric double layer capacitors, and electric double layer small capacitors mounted on them, a laminate including a heat resistant resin layer / adhesive layer / metal foil layer / adhesive layer / thermoplastic resin layer (inner sealant layer) is used instead of the conventional metal can. In addition, power sources for electric vehicles, large power sources for electric storage applications, electric double layer capacitors, etc. are also increasingly exteriorly packaged with the above-described laminate (exterior material). By performing bulging molding or deep drawing molding on the aforementioned laminate, a three-dimensional shape such as a substantially rectangular parallelepiped shape is formed. By forming such a three-dimensional shape, a housing space for housing the main body portion of the electric storage device can be ensured.

[0003] In order to be formed into such a three-dimensional shape in a good state without pinholes, breaks, etc., it is required to improve the slidability of the surface of the inner sealant layer. As a method for improving the slidability of the surface of the inner sealant layer, adding an anti-blocking agent to the inner sealant layer can be cited. However, if the anti-blocking agent is excessively added to the inner sealant layer, the inner sealant layer is likely to become cloudy, and due to the cloudiness of the sealant layer, there is a problem that even if interlayer peeling (delamination) occurs in the exterior material, it is likely to be overlooked in quality inspection.

[0004] Patent Document 1 proposes an exterior material for an electric storage device that can ensure good slidability during molding, can ensure good moldability, and can suppress cloudiness in the exterior material.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent No. 6936093 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] For example, in a state where an electric storage device main body portion is housed in an exterior case obtained by molding an exterior material for an electric storage device as described in Patent Document 1, an electric storage device can be obtained by thermally bonding the inner sealant layer. The exterior material for an electric storage device is formed by deep drawing molding, bulging molding, etc., but from the viewpoints of expansion of use, productivity of the electric storage device, etc., it is desired to suppress the generation of pinholes, cracks, etc., and increase the molding depth and improve the moldability.

[0010] An object of the present invention is to provide an exterior material for a power storage device capable of achieving high formability, an exterior case for a power storage device using the same, and a power storage device.

[0011] Means for Solving the Problem

[0012] Specific means for achieving the above problems are as follows.

[0013] <1> An adhesive that contains an adhesive component and has a shear adhesive strength of 0.7 MPa or more, and is used for forming an adhesive layer between a base material layer and a barrier layer when manufacturing an exterior material for a power storage device.

[0014] <2> An adhesive that contains an adhesive component and an additive, and has a shear adhesive strength increase rate of 20% or more compared to a comparative adhesive having the same composition except for not containing the above additive, and is used for forming an adhesive layer between a base material layer and a barrier layer when manufacturing an exterior material for a power storage device.

[0015] <3> The adhesive according to <1> or <2>, wherein the adhesive component contains at least one selected from the group consisting of polyester and polyurethane.

[0016] <4> The adhesive according to any one of <1> to <3>, which further contains a metal salt containing an amino group and a carbonyl group.

[0017] <5> The adhesive according to any one of <2> to <4>, wherein the additive contains a metal salt containing an amino group and a carbonyl group.

[0018] <6> The adhesive according to <4>, wherein the content rate of the metal salt is 0.5 mass% to 4 mass% with respect to the solid content of the adhesive.

[0019] <7> The adhesive according to <5>, wherein the content rate of the metal salt is 0.5 mass% to 4 mass% with respect to the solid content of the adhesive.

[0020] <8> An exterior material for a power storage device, in which a base material layer, an adhesive layer formed from the adhesive according to any one of <1> to <7>, a barrier layer, and a sealant layer are laminated in this order.

[0021] <9> A method for manufacturing an exterior material for a power storage device, which includes:

[0022] A step of applying the adhesive according to any one of <1> to <7> to the base material layer or the barrier layer; and

[0023] A step of laminating the barrier layer or the base material layer on the applied adhesive.

[0024] <10>The outer housing for a power storage device, which is a molded body of the outer packaging material for a power storage device described in <8>.

[0025] <11>A power storage device, which includes:

[0026] A main body portion of the power storage device; and

[0027] An outer packaging member that houses the main body portion of the power storage device and includes the outer packaging material for a power storage device described in <10>.

[0028] Effects of the Invention

[0029] According to the present invention, it is possible to provide an outer packaging material for a power storage device with high moldability, and an outer housing for a power storage device and a power storage device using the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic cross-sectional view showing an example of the outer packaging material for a power storage device of the present invention.

[0031] Figure 2 It is a schematic cross-sectional view showing an example of a power storage device.

[0032] Figure 3 It shows Figure 2 A schematic perspective view showing the components of the power storage device in a separated state. DETAILED DESCRIPTION

[0033] Hereinafter, the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In the following embodiments, its constituent elements (including element steps, etc.) are not essential unless otherwise specifically stated. The same applies to numerical values and their ranges, and the present invention is not limited.

[0034] In the present invention, the term "process" includes not only processes independent of other processes, but also processes that are included as long as the purpose of the process can be achieved even when it cannot be clearly distinguished from other processes.

[0035] In the present invention, in the numerical range indicated by "~", the numerical values described before and after "~" are included as the minimum value and the maximum value, respectively.

[0036] In the numerical ranges described stepwise in the present invention, the upper limit value or the lower limit value described in one numerical range can be replaced with the upper limit value or the lower limit value of other numerically described ranges. In addition, in the numerical ranges described in the present invention, the upper limit value or the lower limit value of the numerical range can be replaced with the value shown in the examples.

[0037] In the present invention, various corresponding substances may be included in each component. When there are multiple substances belonging to each component in the composition, unless otherwise specified, the content rate or content of each component refers to the total content rate or content of the multiple substances present in the composition.

[0038] In the present invention, multiple particles may be included in the particles belonging to each component. When there are multiple particles belonging to each component in the composition, unless otherwise specified, the particle size of each component refers to the value for the mixture of the multiple particles present in the composition.

[0039] Hereinafter, the adhesives of the first embodiment, the second embodiment, or the third embodiment of the adhesive of the present invention will be described. It should be noted that the adhesive of the present invention is not limited to the following embodiments. In addition, within the scope of achieving the effects of the present invention, the configurations of each embodiment may also be combined.

[0040] <Adhesive>

[0041] [First Embodiment]

[0042] The adhesive according to the first embodiment of the present invention contains an adhesive component and has a shear bond strength of 0.7 MPa or more, and is an adhesive for forming an adhesive layer between a base material layer and a barrier layer during the production of an exterior material for an electric storage device.

[0043] By making the shear bond strength of the adhesive of the first embodiment 0.7 MPa or more, when forming an exterior material for an electric storage device by deep drawing, bulging, etc., the generation of pinholes, cracks, etc. can be suppressed, and the forming depth can be increased and the formability can be improved. It is presumed that the reason is that by increasing the shear bond strength, the barrier layer follows the base material layer more during forming, so it is not easily stretched locally and necking is less likely to occur.

[0044] The shear bond strength of the adhesive of the present invention is preferably 0.75 MPa or more, more preferably 0.8 MPa or more.

[0045] There is no particular limitation on the upper limit of the shear bond strength of the adhesive of the present invention.

[0046] The shear bond strength of the adhesive is measured by the method described in the examples. For example, it can be the shear bond strength of the adhesive when the base material layer is a nylon film and the barrier layer is an aluminum foil.

[0047] In the present invention, the exterior material for a power storage device is a component that houses the main body of the power storage device and is used to fabricate the power storage device. For example, the exterior material for a power storage device is a component in which a base material layer, an adhesive layer (also referred to as an outer adhesive layer) formed from the adhesive of the present invention, a barrier layer, and a sealant layer are laminated in sequence, and an adhesive layer (also referred to as an inner adhesive layer) may also be formed between the barrier layer and the sealant layer.

[0048] The adhesive of the present invention contains an adhesive component. The adhesive can be any of chemical reaction type, solvent evaporation type, hot melt type, hot press type, etc. Additionally, it can be a two-component curable adhesive (two-component adhesive), a one-component curable adhesive (one-component adhesive), or a resin without a curing reaction.

[0049] Examples of the adhesive component contained in the adhesive include: polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyethylene isophthalate, and copolyester; polyethers; polyurethanes; epoxy resins; phenolic resins; polyamides such as nylon 6, nylon 66, nylon 12, and copolyamide; polyolefin resins such as polyolefins, cyclic polyolefins, acid-modified polyolefins, and acid-modified cyclic polyolefins; polyvinyl acetate; cellulose; (meth)acrylic resins; polyimides; polycarbonates; amino resins such as urea resins and melamine resins; rubbers such as chloroprene rubber, nitrile rubber, and styrene-butadiene rubber; silicone resins; and so on.

[0050] Examples of the adhesive component in the thermosetting adhesive include polyester-based resins, polyolefin-based resins, epoxy resins, and (meth)acrylic resins.

[0051] The adhesive component can contain one kind alone or two or more kinds.

[0052] The adhesive component contained in the adhesive preferably contains at least one selected from the group consisting of polyester and polyurethane.

[0053] The adhesive of the present invention preferably contains a metal salt containing an amino group and a carbonyl group (hereinafter also referred to as a specific metal salt). By using the specific metal salt, there is a tendency to improve the adhesion between the adhesive and the base material layer (e.g., nylon film) and the barrier layer (e.g., aluminum foil).

[0054] The specific metal salt can contain one kind alone or two or more kinds.

[0055] The specific metal salt preferably contains two or more amino groups and two or more carbonyl groups, and more preferably contains three amino groups and three carbonyl groups.

[0056] The specific metal salt can contain a ring structure, can contain an amino group and a carbonyl group within the ring structure, or can contain an isocyanurate ring.

[0057] Examples of the metal contained in the specific metal salt include zinc, titanium, chromium, manganese, iron, cobalt, copper, molybdenum, cadmium, aluminum, beryllium, magnesium, calcium, strontium, barium, etc. Among them, zinc is preferred.

[0058] Examples of the specific metal salt include zinc cyanurate, titanium cyanurate, chromium cyanurate, manganese cyanurate, iron cyanurate, cobalt cyanurate, copper cyanurate, molybdenum cyanurate, cadmium cyanurate, aluminum cyanurate, beryllium cyanurate, magnesium cyanurate, calcium cyanurate, strontium cyanurate, and barium cyanurate.

[0059] From the viewpoint of shear bond strength, the content rate of the specific metal salt is preferably 0.5% by mass to 4% by mass, more preferably 0.8% by mass to 3% by mass, and still more preferably 1% by mass to 2.5% by mass, relative to the solid components of the adhesive.

[0060] The adhesive of the present invention may also contain other components. Examples of the other components include colorants, thermoplastic elastomers, tackifiers, fillers, etc. If a colorant is contained in the adhesive, a colored exterior material for a power storage device can be obtained. As the colorant, known colorants such as pigments and dyes can be used. In addition, the colorant may contain 1 type alone or may contain 2 or more types.

[0061] [Second Embodiment]

[0062] The adhesive according to the second embodiment of the present invention is an adhesive containing an adhesive component and an additive, and the rate of increase in shear bond strength relative to a comparative adhesive having the same composition except for not containing the aforementioned additive is 20% or more. The aforementioned adhesive is used for forming an adhesive layer between a base material layer and a barrier layer when manufacturing an exterior material for a power storage device.

[0063] The adhesive of the second embodiment has an increased shear bond strength due to the rate of increase in shear bond strength relative to the comparative adhesive being 20% or more, and can improve formability when forming an exterior material for a power storage device by deep drawing, bulging, etc.

[0064] The rate of increase in shear bond strength relative to the comparative adhesive is preferably 25% or more, more preferably 30% or more.

[0065] There is no particular limitation on the upper limit of the rate of increase in shear bond strength relative to the comparative adhesive.

[0066] The preferred constitution of the adhesive component contained in the adhesive of the second embodiment is the same as the preferred constitution of the adhesive component contained in the adhesive of the first embodiment.

[0067] Examples of the additives contained in the adhesive of the second embodiment include the aforementioned specific metal salts, the aforementioned other components, etc. The adhesive preferably contains a specific metal salt as the aforementioned additive. From the viewpoint of shear bond strength, the preferred content rate of the specific metal salt is preferably 0.5% by mass to 4% by mass, more preferably 0.8% by mass to 3% by mass, and still more preferably 1% by mass to 2.5% by mass, relative to the solid components of the adhesive.

[0068] [Third Embodiment]

[0069] The adhesive of the third embodiment of the present invention contains an adhesive component and a metal salt containing an amino group and a carbonyl group (specific metal salt). The content rate of the specific metal salt is 0.5% by mass to 4% by mass relative to the solid components of the adhesive.

[0070] In the adhesive of the third embodiment, by adjusting the content rate of the specific metal salt, the shear bond strength can be improved. As a result, the formability of the exterior material for the electrical storage device is improved.

[0071] The adhesive of the third embodiment can be used for forming the adhesive layer between the base material layer and the barrier layer when manufacturing the exterior material for the electrical storage device, and can also be used for other purposes.

[0072] The matters described in the first embodiment or the second embodiment can also be appropriately combined with the adhesive of the third embodiment.

[0073] [Exterior Material for Electrical Storage Device]

[0074] The exterior material for the electrical storage device of the present invention is a component in which a base material layer, an adhesive layer formed of the aforementioned adhesive of the present invention, a barrier layer, and a sealant layer are laminated in sequence.

[0075] Hereinafter, the layer constitution of the exterior material for the electrical storage device will be described.

[0076] (Base Material Layer)

[0077] The exterior material for the electrical storage device includes a base material layer.

[0078] The base material layer is preferably formed of a heat-resistant resin layer. The heat-resistant resin is preferably a resin that does not melt at the heat-sealing temperature when heat-sealing the exterior material. As the heat-resistant resin, a resin having a high melting point is preferred. For example, it is preferably higher than the melting points of the respective layers contained in the sealant layer, preferably has a melting point 10°C or more higher than the melting point of the layer having the highest melting point among the respective layers contained in the sealant layer, and preferably has a melting point 20°C or more higher.

[0079] As the base material layer, for example, polyamide films such as nylon films, polyester films, etc. can be cited, and these films can be stretched films. As the stretched film, biaxially stretched polyamide films such as biaxially stretched nylon films, biaxially stretched polybutylene terephthalate (PBT) films, biaxially stretched polyethylene terephthalate (PET) films, biaxially stretched polyethylene naphthalate (PEN) films, etc. can be cited. As the nylon film, 6-nylon film, 6,6-nylon film, MXD-nylon film, etc. can be cited.

[0080] The base material layer can be a single layer or a multi-layer formed of two or more layers. As the multi-layer, a polyester film / polyamide film (for example, a PET film / nylon film) can be cited. A bonding layer can also be formed between the polyester film and the polyamide film. As the adhesive constituting the bonding layer, there is no particular limitation, and for example, a thermosetting adhesive, the adhesive of the present invention for forming the outer bonding layer described later, etc. can be cited. As the thermosetting adhesive, there is no particular limitation, and for example, polyurethane-based adhesives, poly(meth)acrylate-based adhesives, modified polypropylene-based adhesives, polyester-based adhesives, polyamide-based adhesives, olefin-based adhesives, epoxy-based adhesives, acrylic-based adhesives, etc. can be cited.

[0081] The thickness of the base material layer can be 2 μm to 50 μm. For example, when the base material layer is a polyester film, its thickness can be 2 μm to 50 μm, and when the base material layer is a nylon film, its thickness can be 7 μm to 50 μm.

[0082] (Outer bonding layer)

[0083] A bonding layer (also referred to as an outer bonding layer) is provided between the base material layer and the barrier layer described later. The adhesive constituting the outer bonding layer is the adhesive of the present invention described above, and can also be the adhesive of the first embodiment, the adhesive of the second embodiment, or the adhesive of the third embodiment.

[0084] The thickness of the outer adhesive layer can be 1 μm to 7 μm. Among them, from the viewpoints of thinning and lightening of the packaging material, the thickness of the outer bonding layer is preferably 1 μm to 5 μm.

[0085] The outer bonding layer can be a single layer or a multi-layer of two or more layers. In the case of a multi-layer, for example, it can also be a combination of a bonding layer containing a colorant and a bonding layer not containing a colorant.

[0086] (Barrier layer)

[0087] The exterior material for the electric storage device includes a barrier layer.

[0088] The barrier layer serves to impart gas barrier properties to the outer packaging material to inhibit the intrusion of oxygen, moisture, etc. There is no particular limitation on the barrier layer, and examples thereof include metal foils, vapor deposition films, resin layers, etc. As the vapor deposition film, examples include metal vapor deposition films, inorganic oxide vapor deposition films, carbon-containing inorganic oxide vapor deposition films, etc. There is no particular limitation on the metal foil, and examples include aluminum foil, SUS foil (stainless steel foil), Cu foil, Ni foil, Ti foil, etc. Among them, aluminum foil and SUS foil (stainless steel foil) are preferred. As the resin for the resin layer, examples include fluororesins, ethylene-vinyl alcohol copolymers, etc. As the fluororesin, examples include polymers mainly composed of polyvinylidene chloride, chlorotrifluoroethylene (CTFE), polymers mainly composed of tetrafluoroethylene (TFE), polymers having fluoroalkyl groups, polymers mainly composed of fluoroalkyl units, etc.

[0089] The barrier layer can be a single layer or a multi-layer of two or more layers. In the case of a multi-layer, it can be a laminate of the same kind of layers or a laminate of different kinds of layers. As a laminate of different kinds of layers, an example is a combination of a vapor deposition film and a resin layer.

[0090] From the viewpoints of suppressing the generation of pinholes during rolling and formability, the thickness of the barrier layer can be 5 μm to 120 μm, or can be 10 μm to 80 μm.

[0091] Chemical conversion treatment can be performed on at least one of the surface on the substrate layer side and the surface on the adhesive layer side of the metal foil. For example, it can have an anti-corrosion layer. By providing the anti-corrosion layer, corrosion of the metal foil surface caused by the contents (such as the electrolyte of the battery, etc.) can be suppressed. For example, the metal foil can be chemically converted to form an anti-corrosion layer by the treatment described below.

[0092] For example, after coating any one of the following aqueous solutions 1) to 3) on the surface of the degreased metal foil and drying, chemical conversion treatment is thus performed.

[0093] 1) Containing phosphoric acid,

[0094] chromic acid, and

[0095] an aqueous solution of a mixture of at least one compound selected from the group consisting of metal salts of fluorides and non-metal salts of fluorides;

[0096] 2) Containing phosphoric acid,

[0097] at least one resin selected from the group consisting of acrylic resins, chitosan derivative resins, and phenolic resins, and

[0098] an aqueous solution of a mixture of at least one compound selected from the group consisting of chromic acid and chromium(III) salts;

[0099] 3) Containing phosphoric acid,

[0100] At least one resin selected from the group consisting of acrylic resins, chitosan derivative resins, and phenolic resins,

[0101] At least one compound selected from the group consisting of chromic acid and chromium(III) salts, and

[0102] An aqueous solution of a mixture of at least one compound selected from the group consisting of metal salts of fluorides and non-metal salts of fluorides.

[0103] The chemical conversion film formed by chemical conversion treatment preferably has a chromium adhesion amount (per side) of 0.1 mg / m 2 ~50 mg / m 2 and more preferably 2 mg / m 2 ~20 mg / m 2 .

[0104] (Inner adhesive layer)

[0105] An adhesive layer (also referred to as an inner adhesive layer) may be provided between the barrier layer and the sealant layer described later, and the barrier layer and the sealant layer may be integrated via the inner adhesive layer.

[0106] The adhesive constituting the inner adhesive layer is not particularly limited, and examples thereof include thermosetting adhesives, the adhesives of the present invention for forming the aforementioned outer adhesive layer, etc. As the thermosetting adhesive, there is no particular limitation, and examples thereof include olefin-based adhesives, epoxy-based adhesives, acrylic-based adhesives, acid-modified polyolefin-based adhesives such as maleic anhydride-modified polypropylene, etc.

[0107] The thickness of the inner adhesive layer may be 1 μm to 5 μm. Among them, from the viewpoints of thinning and lightening of the packaging material, the thickness of the inner adhesive layer is preferably 1 μm to 3 μm.

[0108] When the inner adhesive layer is composed of an acid-modified polyolefin-based adhesive, the thickness of the inner adhesive layer may be 1 μm to 50 μm, or may be 10 μm to 50 μm.

[0109] (Sealant layer)

[0110] The exterior material for a power storage device includes a sealant layer. The sealant layer is a layer that plays a role of imparting heat sealability to the exterior material. For example, the sealant layer includes one or more heat-sealable resin layers, and may also include two or three heat-sealable resin layers.

[0111] The heat-sealable resin layer contains a heat-sealable resin, and may also contain a lubricant, incompatible particles, and other components described later as needed.

[0112] In order to melt at the heat-sealing temperature, a heat-sealing resin is selected as a resin having a melting point below the heat-sealing temperature. The heat-sealing resin is not particularly limited as long as it has the above melting point, and is preferably at least one selected from the group consisting of polyethylene, polypropylene, olefin copolymers, acid-modified products thereof, and ionomers. "Polyethylene, polypropylene, olefin copolymers, acid-modified products thereof, and ionomers" are also referred to as "specific polyolefins".

[0113] Among the resins contained in the heat-sealing resin layer, the proportion of the specific polyolefin is preferably 50% by mass or more, more preferably 60% by mass or more, further preferably 70% by mass or more, particularly preferably 80% by mass or more, extremely preferably 90% by mass or more, and may be 95% by mass or more, may be 98% by mass or more, or may be 99% by mass or more.

[0114] The heat-sealing resin layer may be configured to contain a single heat-sealing resin or may be configured to contain two or more heat-sealing resins.

[0115] The plurality of heat-sealing resin layers contained in the sealant layer may be each composed of the same heat-sealing resin or may be composed of different heat-sealing resins.

[0116] The heat-sealing resin layer in the sealant layer may further contain a lubricant.

[0117] The lubricant is not particularly limited, and examples thereof include fatty acid amides. The fatty acid amide is not particularly limited, and examples thereof include saturated fatty acid amides, unsaturated fatty acid amides, substituted amides, hydroxymethyl amides, saturated fatty acid bisamides, unsaturated fatty acid bisamides, fatty acid ester amides, aromatic bisamides, and the like.

[0118] The lubricant may be contained in any layer of the sealant layer or may not contain a lubricant.

[0119] The heat-sealing resin layer in the sealant layer may further contain incompatible particles.

[0120] The incompatible particles may be inorganic particles, organic particles, metal particles, composite particles thereof, etc. From the viewpoint of suppressing deformation caused by heat during heat melting, the incompatible particles are preferably inorganic particles, metal particles, or composite particles thereof, and from the viewpoints of further ensuring the insulating function of the sealant layer and weight reduction, inorganic particles, organic particles, or composite particles thereof are preferred. From these comprehensive viewpoints, the incompatible particles are more preferably inorganic particles.

[0121] The incompatible particles may be used alone or two or more thereof may be used in combination.

[0122] Examples of the inorganic particles include inorganic oxide particles (such as silica particles, alumina particles, and titanium oxide particles), inorganic carbonate particles (such as calcium carbonate particles and barium carbonate particles), and inorganic silicate particles (such as aluminum silicate particles, talc particles, and kaolin particles).

[0123] Examples of the organic particles include acrylic resin particles, polyolefin resin particles (such as polyethylene resin particles and polypropylene resin particles), and polystyrene resin particles.

[0124] The incompatible particles may be contained in any layer of the sealant layer or may not be contained. Additionally, the content ratio of the incompatible particles may be changed in multiple heat-sealable resin layers.

[0125] The heat-sealable resin layer in the sealant layer may contain other components.

[0126] Examples of the other components include antioxidants, plasticizers, ultraviolet absorbers, mildew-proof agents, colorants (such as pigments and dyes), antistatic agents, rust inhibitors, moisture absorbers, and oxygen absorbers. There is no particular limitation on the plasticizer, and examples thereof include glycerol fatty acid ester monoglyceride, acetylated glycerol fatty acid ester monoglyceride, organic acid glycerol fatty acid ester monoglyceride, medium-chain fatty acid triglyceride of glycerol fatty acid ester, polyglycerol fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, special fatty acid ester, and higher alcohol fatty acid ester.

[0127] The other components may be contained in any layer of the sealant layer or may not be contained. Additionally, the composition or content ratio of the other components may be changed in multiple heat-sealable resin layers.

[0128] Hereinafter, Figure 1 An example of the exterior material for an electric storage device of the present invention is shown. Figure 1 FIG. is a schematic cross-sectional view showing an example of the exterior material for an electric storage device of the present invention.

[0129] The exterior material 1 for an electric storage device sequentially includes a base material layer 2, a barrier layer 4, and a sealant layer 3. The sealant layer 3 sequentially includes a first heat-sealable resin layer 7, a second heat-sealable resin layer 8, and a third heat-sealable resin layer 9 from the barrier layer 4 side. And, an outer adhesive layer 5 is provided between the base material layer 2 and the barrier layer 4, and an inner adhesive layer 6 is provided between the barrier layer 4 and the A layer 7.

[0130] <Method for manufacturing an exterior material for an electric storage device>

[0131] The manufacturing method of the exterior material for the electricity storage device is not particularly limited as long as the above-mentioned exterior material for the electricity storage device can be obtained. For example, the manufacturing method of the exterior material for the electricity storage device may include a step of applying the above-mentioned adhesive of the present invention to the base material layer or the barrier layer, and a step of laminating the above-mentioned barrier layer or the above-mentioned base material layer on the above-mentioned adhesive. As an example of the manufacturing method of the exterior material for the electricity storage device, the manufacturing method of the exterior material 1 for the electricity storage device shown in Figure 1 will be described below.

[0132] Prepare a laminate A in which a base material layer 2, an outer adhesive layer 5, and a barrier layer 4 are laminated in sequence. The laminate A can be produced by the following dry lamination method: The adhesive component for forming the outer adhesive layer 5 is applied to the base material layer 2 or the barrier layer 4 by a gravure coating method, a roll coating method, etc., and after drying, the barrier layer 4 or the base material layer 2 is laminated thereon. In the case where the adhesive component is a curable resin, after the barrier layer 4 or the base material layer 2 is laminated on the outer adhesive layer 5, the outer adhesive layer 5 is cured by heating or the like.

[0133] Next, a sealant layer 3 is provided on the barrier layer 4 of the laminate A. For the sealant layer 3, the sealant layer 3 previously formed as a resin film can be disposed on the barrier layer 4 (the first method), or the resin material for forming the sealant layer 3 can be applied to the barrier layer 4 by extrusion molding, coating, etc. to form the sealant layer 3 (the second method).

[0134] In the first method, a resin film of a laminate of multiple layers such as a first heat-sealable resin layer 7, a second heat-sealable resin layer 8, and a third heat-sealable resin layer 9 can be produced by a coextrusion method or the like.

[0135] In the case of the first method, the barrier layer 4 and the sealant layer 3 are bonded by an inner adhesive layer 6. In the case of the second method, the inner adhesive layer 6 can be omitted, or the inner adhesive layer 6 can be provided.

[0136] In the case where the inner adhesive layer 6 is provided between the barrier layer 4 and the sealant layer 3, the inner adhesive layer 6 and the sealant layer 3 can be laminated by an extrusion lamination method, a thermal lamination method, a sandwich lamination method, a dry lamination method, etc.

[0137] As the extrusion lamination method, there can be mentioned a method of laminating by extruding the inner adhesive layer 6 and the sealant layer (the first heat-sealable resin layer 7, the second heat-sealable resin layer 8, and the third heat-sealable resin layer 9) on the barrier layer 4 of the laminate A (coextrusion lamination method, tandem lamination method), etc.

[0138] As the thermal lamination method, there can be mentioned a method of laminating a laminate B in which an inner adhesive layer 6 and a sealant layer 3 are separately formed so that the inner adhesive layer 6 of the laminate B faces the barrier layer 4 of the laminate A; a method of forming a laminate C having an inner adhesive layer 6 on the barrier layer 4 of the laminate A and laminating the inner adhesive layer 6 of the laminate C with the sealant layer 3, etc.

[0139] As the sandwich lamination method, there can be mentioned a method of flowing a molten inner adhesive layer 6 between the barrier layer 4 of the laminate A and a sealant layer 3 previously formed in a film shape, etc. An adhesive resin such as an acid-modified polyolefin-based adhesive can be flowed between the barrier layer 4 of the laminate A and a sealant layer 3 previously formed in a film shape, and after sandwich lamination, heating is performed using a hot bonding roll, and the barrier layer 4 and the sealant layer 3 are bonded through the inner adhesive layer 6 (hot bonding resin).

[0140] As the dry lamination method, there can be mentioned a method of solution-coating an adhesive component for forming the inner adhesive layer 6 on the barrier layer 4 of the laminate A, drying or baking it, and laminating a sealant layer 3 previously formed in a film shape on the inner adhesive layer 6, etc.

[0141] <Outer packaging case for a power storage device>

[0142] The outer packaging case for a power storage device of the present invention is a molded body of the aforementioned outer packaging material for a power storage device. The outer packaging material for a power storage device can be molded by deep drawing, bulging molding, etc. As the shape of the outer packaging case for a power storage device, for example, those described later Figure 2 and Figure 3 of the outer packaging case 10 can be mentioned.

[0143] <Power storage device>

[0144] The power storage device of the present invention includes a power storage device main body portion and an outer packaging member that houses the aforementioned power storage device main body portion and includes the aforementioned outer packaging material for a power storage device of the present invention. The outer packaging member can be configured to include the outer packaging case for a power storage device of the present invention.

[0145] An example of a power storage device 100 using the outer packaging material 1 for a power storage device of the present invention is shown in Figure 2 and Figure 3 . Figure 2 It is a schematic cross-sectional view showing an example of a power storage device. Figure 3 is Figure 2 a schematic perspective view showing the components of the power storage device in a separated state. The power storage device 100 is a lithium ion secondary battery.

[0146] In Figure 2 and Figure 3In this case, an exterior member 15 is composed of an exterior housing 10 which is a molded body serving as an exterior material 1 and a planar exterior material 1. A power storage device main body portion 110 is housed in a housing recess of the exterior housing 10. Further, the planar exterior material 1 is arranged with the side of the sealant layer 3 being the inner side ( Figure 2 and Figure 3 the lower side in the following) and the peripheral portion of the sealant layer 3 of the planar exterior material 1 and the sealant layer 3 of the flange portion (sealing peripheral portion) 37 of the exterior housing 10 are hermetically joined by heat fusion (heat sealing) and thus sealed.

[0147] Figure 2 In the following, reference numeral 39 denotes a heat seal portion formed by joining (welding) the peripheral portion of the exterior material 1 and the flange portion (sealing peripheral portion) 37 of the exterior housing 10. In the power storage device 100, the front end portion of the tab connected to the power storage device main body portion 110 is led out to the outside of the exterior member 15, but illustration thereof is omitted.

[0148] The power storage device main body portion 110 is not particularly limited, and examples thereof include a battery main body portion, a large-capacitance capacitor main body portion, and a small-capacitance capacitor main body portion.

[0149] From the viewpoint of reliably performing sealing, the width of the heat seal portion 39 is preferably set to 0.5 mm or more, and more preferably set to 3 mm to 15 mm.

[0150] The form of the exterior member 15 is not limited to Figure 2 and Figure 3 and may be such that the peripheries are heat-fused (heat-sealed) with a pair of planar exterior materials 1, or may be such that the peripheries are heat-fused (heat-sealed) with a pair of exterior housings 10.

[0151] Examples

[0152] Next, examples of the present invention will be described, but the present invention is not particularly limited to these examples.

[0153] [Example 1]

[0154] (Preparation of Adhesive)

[0155] Zinc cyanurate is added to a two-component curable urethane-based adhesive component containing a polyester polyol compound and an aromatic polyisocyanate compound to prepare an adhesive for use in an exterior material of a power storage device. At this time, 1% by mass of zinc cyanurate is added relative to the total amount of the urethane-based adhesive component.

[0156] (Production of Laminate A)

[0157] A chemical conversion treatment solution containing phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water, and alcohol was applied to both sides of an aluminum foil having a thickness of 40 μm, and then dried at 180°C to form a chemical conversion film. The chromium deposition amount of the chemical conversion film was 10 mg / m per side. 2 .

[0158] Next, an adhesive for preparing an external packaging material for a power storage device was applied to one side of the aluminum foil subjected to the chemical conversion treatment, and a 25 μm thick biaxially stretched 6 nylon film was dry laminated (laminated) via the adhesive. Both sides of the biaxially stretched 6 nylon film were subjected to corona treatment. Thus, a laminate A having a substrate layer, an adhesive layer, and a barrier layer laminated in this order was prepared.

[0159] (Determination of shear bond strength)

[0160] Two laminates A were prepared. The adhesive prepared as described above was applied to the central portion of the aluminum foil side of the laminate A in the width direction so as to have a width of 15 mm. The other laminate A was laminated on the adhesive of 15 mm width so that the adhesive of 15 mm width was opposite to the nylon side of the other laminate A, and aged (heated) at 50° C. for 5 days. Thus, a laminate D consisting of the laminate A, the adhesive of 15 mm width, and the laminate A was prepared.

[0161] The laminate D was cut in the thickness direction along the width direction to prepare a sample for measuring shear bond strength consisting of the cut laminate A, the adhesive of 15 mm×15 mm, and the cut laminate A.

[0162] The shear bond strength of the adhesive of 15 mm×15 mm was measured by pulling a pair of cut laminates A up and down for the sample for shear bond strength measurement.

[0163] (Manufacturing of exterior materials for power storage devices)

[0164] A chemical conversion treatment solution containing phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water, and alcohol was applied to both sides of an aluminum foil having a thickness of 35 μm, and then dried at 180°C to form a chemical conversion film. The chromium adhesion amount of the chemical conversion film was 10 mg / m per side. 2 .

[0165] Next, an adhesive for making an outer packaging material for a storage device is applied to one side of the aluminum foil treated with the chemical conversion, and a biaxially stretched 6 nylon film with a thickness of 15 μm is dry-laminated (laminated) through the adhesive. The laminating surface of the biaxially stretched 6 nylon film is subjected to a corona treatment. Next, a T-die is used to sequentially stack a first resin layer with a thickness of 4.5 μm formed by an ethylene-propylene random copolymer, a second resin layer with a thickness of 21 μm formed by an ethylene-propylene block copolymer resin, and a first resin layer with a thickness of 4.5 μm formed by an ethylene-propylene random copolymer. These three layers are co-extruded to obtain a sealant film (first resin layer / second resin layer / first resin layer) with a thickness of 30 μm formed by stacking these three layers. Then, the first resin layer of one side of the sealant film (inner layer) was overlapped on the other side of the aluminum foil after the dry lamination via a two-component curing maleic acid-modified polypropylene adhesive (curing agent is a multifunctional isocyanate), and was sandwiched between a rubber roller and a laminating roller heated to 100° C. for pressure bonding, thereby performing dry lamination. Then, it was aged at 50° C. for 5 days (heating), thereby producing an external packaging material for a storage battery device with a thickness of 86 μm.

[0166] (Determination of tensile elongation)

[0167] The above-mentioned external packaging material for a power storage device was cut into 15 mm×150 mm to prepare a sample for tensile elongation. A tensile test was performed under the conditions of a speed of 100 mm / min and a gap of 100 mm to measure the elongation at break. The results are shown in Table 1.

[0168] (Molding evaluation)

[0169] The produced external packaging material for the power storage device was cut into 100 mm×125 mm pieces as a raw material for forming, and then deep-drawn using a punch (punch shape: 33 mm×54 mm, corner R: 2 mm, punch shoulder R: 1.3 mm) and a die (die shape: die shoulder R: 1 mm) using a punching machine (model: TP-25C-XZ) manufactured by AMADA Co., Ltd.

[0170] The deep drawing was performed by bringing the top surface of the punch into contact with the sealant layer of the molding material so that the base material layer protruded outward, and by changing the molding depth D in units of 0.5 mm.

[0171] Then, the corner portions of the molded article are illuminated, and the transmitted light due to pinholes, cracks, etc. is visually observed to search for the maximum molding depth (mm) at which good molding without pinholes and cracks can be achieved. In Examples 1 to 3, 7 to 9 and Comparative Examples 3 and 4 using urethane-based adhesives, based on the maximum molding depth (mm) of Comparative Example 1, and in Examples 4 to 6 and Comparative Example 5 using ester-based adhesives, based on the maximum molding depth (mm) of Comparative Example 2, the moldability is evaluated based on the following evaluation criteria. An evaluation of A to C is judged to have good moldability, and an evaluation of D is judged to have poor moldability. The results are shown in Table 1.

[0172] - Evaluation Criteria -

[0173] A: The maximum molding depth is increased by 1.5 mm or more compared to Comparative Example 1 or 2

[0174] B: The maximum molding depth is increased by 1.0 mm or more and less than 1.5 mm compared to Comparative Example 1 or 2

[0175] C: The maximum molding depth is increased by 0.5 mm or more and less than 1.0 mm compared to Comparative Example 1 or 2

[0176] D: The maximum molding depth is increased by less than 0.5 mm compared to Comparative Example 1 or 2, or the maximum molding depth is the same as or less than that of Comparative Example 1 or 2

[0177] [Examples 2 and 3]

[0178] In Example 1, 2% by mass or 3% by mass of zinc cyanurate was added relative to the total amount of the urethane-based adhesive components. Except for this, an adhesive for manufacturing an outer packaging material for an electric storage device was prepared in the same manner as in Example 1. Then, laminate A and an outer packaging material for an electric storage device were produced in the same manner as in Example 1, and the above-described physical property measurements and molding evaluations were performed.

[0179] [Example 4]

[0180] (Preparation of Adhesive)

[0181] Zinc cyanurate was added to a two-component curable ester-based adhesive component containing a polyester polyol compound and an aliphatic polyisocyanate compound to prepare an adhesive for manufacturing an outer packaging material for an electric storage device. At this time, 1% by mass of zinc cyanurate was added relative to the total amount of the ester-based adhesive component. Then, laminate A and an outer packaging material for an electric storage device were produced in the same manner as in Example 1, and the above-described physical property measurements and molding evaluations were performed.

[0182] [Examples 5 and 6]

[0183] In Example 4, 2% by mass or 3% by mass of zinc cyanurate was added relative to the total amount of the ester-based adhesive component, and otherwise, an adhesive for manufacturing an exterior material for an electric storage device was prepared in the same manner as in Example 4. Then, laminate A and an exterior material for an electric storage device were produced in the same manner as in Example 4, and the above-described physical property measurement and molding evaluation were performed.

[0184] [Example 7]

[0185] Zinc cyanurate and a pigment (carbon black) were added to a two-component curable urethane-based adhesive component containing a polyester polyol compound and an aromatic polyisocyanate compound to prepare an adhesive for manufacturing an exterior material for an electric storage device. At this time, 1% by mass of zinc cyanurate was added relative to the total amount of the urethane-based adhesive component, and 4.3% by mass of the pigment was added relative to the total amount of the resin solid components contained in the urethane-based adhesive component. Then, laminate A and an exterior material for an electric storage device were produced in the same manner as in Example 1, and the above-described physical property measurement and molding evaluation were performed.

[0186] [Examples 8 and 9]

[0187] In Example 7, 2% by mass or 3% by mass of zinc cyanurate was added relative to the total amount of the urethane-based adhesive component, and otherwise, an adhesive for manufacturing an exterior material for an electric storage device was prepared in the same manner as in Example 7. Then, laminate A and an exterior material for an electric storage device were produced in the same manner as in Example 7, and the above-described physical property measurement and molding evaluation were performed.

[0188] [Comparative Example 1]

[0189] A two-component curable urethane-based adhesive component containing a polyester polyol compound and an aromatic polyisocyanate compound was used as the adhesive for manufacturing an exterior material for an electric storage device in Comparative Example 1. Then, laminate A and an exterior material for an electric storage device were produced in the same manner as in Example 1, and the above-described physical property measurement and molding evaluation were performed.

[0190] [Comparative Example 2]

[0191] A two-component curable ester-based adhesive component containing a polyester polyol compound and an aliphatic polyisocyanate compound was used as the adhesive for manufacturing an exterior material for an electric storage device in Comparative Example 2. Then, laminate A and an exterior material for an electric storage device were produced in the same manner as in Example 1, and the above-described physical property measurement and molding evaluation were performed.

[0192] [Comparative Example 3]

[0193] In a two-component curable urethane-based adhesive composition containing a polyester polyol compound and an aromatic polyisocyanate compound, a pigment (carbon black) is added to prepare an adhesive for an outer packaging material for an electric storage device. At this time, 4.3% by mass of the pigment is added relative to the total amount of the resin solid components contained in the urethane-based adhesive composition. Then, laminate A and the outer packaging material for the electric storage device are produced in the same manner as in Example 1, and the above-described physical property measurement and molding evaluation are carried out.

[0194] [Comparative Example 4]

[0195] In Example 1, 5% by mass of zinc cyanurate is added relative to the total amount of the urethane-based adhesive composition, and otherwise, an adhesive for an outer packaging material for an electric storage device is prepared in the same manner as in Example 1. Then, laminate A and the outer packaging material for the electric storage device are produced in the same manner as in Example 1, and the above-described physical property measurement and molding evaluation are carried out.

[0196] [Comparative Example 5]

[0197] In Example 4, 5% by mass of zinc cyanurate is added relative to the total amount of the ester-based adhesive composition, and otherwise, an adhesive for an outer packaging material for an electric storage device is prepared in the same manner as in Example 1. Then, laminate A and the outer packaging material for the electric storage device are produced in the same manner as in Example 1, and the above-described physical property measurement and molding evaluation are carried out.

[0198] [Table 1]

[0199]

[0200] As shown in Table 1, by using the adhesives of Examples 1 to 9, the molding evaluation is good as compared with the case of using the adhesives of Comparative Examples 1 to 5.

[0201] In Examples 1 to 3, relative to Comparative Example 1, by adding 1 to 3% by mass of an additive, the shear adhesive strength is increased by 20% or more. In Examples 4 to 6, relative to Comparative Example 2, by adding 1 to 3% by mass of an additive, the shear adhesive strength is increased by 20% or more. In Examples 7 to 9, relative to Comparative Example 3, by adding 1 to 3% by mass of an additive, the shear adhesive strength is increased by 20% or more, and the molding evaluation is improved in all the examples.

Claims

1. An adhesive comprising an adhesive component and having a shear adhesive strength of 0.7 MPa or more, the adhesive being used for forming an adhesive layer between a base layer and a barrier layer when producing an exterior material for a power storage device.

2. An adhesive comprising an adhesive component and an additive, wherein the rate of increase in shear bonding strength is 20% or more relative to a comparative adhesive having the same composition except that the additive is not contained, and the adhesive is used for forming an adhesive layer between a substrate layer and a barrier layer when manufacturing an exterior material for a storage device.

3. The adhesive according to claim 1 or 2, wherein: The adhesive component includes at least one selected from the group consisting of polyester and polyurethane. The adhesive according to claim 3 , further comprising a metal salt containing an amino group and a carbonyl group.

5. The adhesive according to claim 2, wherein: The additive comprises a metal salt containing an amino group and a carbonyl group.

6. The adhesive according to claim 4, wherein The content of the metal salt is 0.5% by mass to 4% by mass based on the solid content of the adhesive.

7. The adhesive according to claim 5, wherein The content of the metal salt is 0.5% by mass to 4% by mass based on the solid content of the adhesive.

8. External packaging materials for power storage devices, wherein: A substrate layer, an adhesive layer formed of the adhesive according to any one of claims 1 to 7, a barrier layer, and a sealant layer are laminated in this order.

9. A method for producing an exterior material for an electrical storage device, comprising: A step of applying the adhesive according to any one of claims 1 to 7 to a substrate layer or a barrier layer; and A step of laminating the barrier layer or the base layer on the adhesive. 10 . An exterior case for a power storage device, which is a molded body of the exterior material for a power storage device according to claim 8 .

11. An electric storage device comprising: a power storage device main body; and An exterior member that houses the power storage device main body and includes the power storage device exterior material according to claim 10 .

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