KR20180020082A - Outer material and power storage device for power storage device - Google Patents

Abstract

The present invention provides an exterior material for a power storage device, which comprises: a heat-resistant resin layer (2) as an outer layer; a sealant layer (3) as an inner layer; and a metal foil layer (4) disposed between the two layers, wherein at least an innermost layer (7) of the sealant layer (3) contains an elastomer-modified olefin-based resin. The elastomer-modified olefin-based resin is made of an olefin-based thermoplastic elastomer-modified homo polypropylene or/and an olefin-based thermoplastic elastomer-modified random copolymer, wherein the olefin-based thermoplastic elastomer-modified random copolymer contains, as copolymer components, propylene and copolymer components other than propylene. Due to the above configuration, the exterior material of the present invention maintains sufficient sealing performance of a seal portion of the exterior material even when exposed to a high temperature environment for a long period of time.

Description

TECHNICAL FIELD [0001] The present invention relates to an exterior material for a power storage device,

The present invention relates to a battery for a portable device such as a smart phone or a tablet, a condenser, a hybrid electric vehicle, an electric vehicle, an exterior material for a battery device such as a battery or a condenser used for a shaft of a wind power, Device.

In the present specification and claims, the term "tensile yield strength" refers to a tensile test piece having a sample width of 15 mm, a distance between a curved line of 50 mm, a tensile speed of 100 mm / min (Tensile yield strength) obtained by measuring the tensile yield strength under the conditions of

BACKGROUND ART Lithium ion secondary batteries are widely used as power sources for, for example, notebook personal computers, video cameras, cellular phones, and the like. As this lithium ion secondary battery, there is used a battery in which a case surrounds the periphery of a battery main body (a main body including a positive electrode, a negative electrode and an electrolyte). As the material for the case (exterior material), for example, an outer layer made of a heat-resistant resin film, an aluminum foil layer, and an inner layer made of a thermoplastic resin film are adhered and integrated in this order (see Patent Document 1).

The power storage device is configured such that the power storage device main body is sandwiched by a pair of jacket materials and the peripheral portions of the pair of jacket materials are fusion-bonded (heat seal) to each other. By sufficiently sealing by such a heat seal bonding, leakage of the electrolytic solution can be prevented.

Patent Document 1: JP-A-2005-22336

However, such a battery such as a lithium ion secondary battery is assumed to be used in a room temperature environment such as a notebook personal computer, a cellular phone, and the like.

In recent years, with the diversification of applications of such lithium ion secondary batteries, new applications for use in the outside exposed under a high-temperature environment represented by use for automobiles have been increasing.

For example, in the use for automobiles, when the vehicle is parked outdoors in summer, the temperature is considerably high. Therefore, even when a battery such as a lithium ion secondary battery is exposed to such a high temperature environment for a long period of time, There has been a demand for development of an exterior material capable of maintaining a good sealing property.

The present invention has been made in view of such a technical background, and an object of the present invention is to provide an exterior material and an electric storage device for a power storage device which can maintain the sealability of the exterior of the exterior material satisfactorily even after long-term exposure under a high temperature environment.

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

[1] An outer sheath for a power storage device comprising a heat-resistant resin layer as an outer layer, a sealant layer as an inner layer, and a metal foil layer disposed between these layers,

Wherein the sealant layer comprises one or more layers,

Wherein at least the innermost layer of the sealant layer contains an elastomer-modified olefin resin,

The elastomer-modified olefin-based resin is composed of an olefin-based thermoplastic elastomer-modified homopolypropylene and / or an olefin-based thermoplastic elastomer-modified random copolymer,

Wherein the olefinic thermoplastic elastomeric modified random copolymer is an olefinic thermoplastic elastomeric modification of a random copolymer containing a copolymerizable component other than propylene and propylene as a copolymerization component.

[2] The outer casing for electric storage devices according to the above 1, wherein the content of the olefinic thermoplastic elastomer in the innermost layer is 0.1 mass% or more and less than 20 mass%.

[3] The outer casing for electric storage devices according to the item 1 or 2, wherein the melting point of the elastomer-modified olefin-based resin constituting the innermost layer is 160 ° C to 180 ° C.

[4] The olefinic thermoplastic elastomer component present in the innermost layer has a plurality of crystallization temperatures, and the lowest crystallization temperature among the plurality of crystallization temperatures is 40 ° C to 80 ° C. [Claim 7] The external appearance of claim 1,

[5] The outer casing for an electric storage device according to any one of items 1 to 4, wherein the MFR of the olefinic thermoplastic elastomer component present in the innermost layer is 0.1 g / 10 min to 1.4 g / 10 min.

[6] The exterior material for an electric storage device according to any one of items 1 to 5, wherein the sealant film constituting the sealant layer has a tensile yield strength at 80 ° C of 3.5 MPa to 15.0 MPa.

[7] The sealant layer is composed of a plurality of layers, a second sealant layer is disposed on a side closest to the metal foil layer in the sealant layer, and the second sealant layer is formed of a mixture of a propylene- The outer sheath for electrical storage devices according to any one of items 1 to 6, which contains at least% by mass and does not contain an elastomer component.

[8] An exterior member for an electric storage device according to any one of items 1 to 7, wherein the metal foil layer and the sealant layer are bonded to each other through an adhesive layer.

[9] The exterior member for an electric storage device according to item 8, wherein the adhesive layer comprises an adhesive containing an olefin resin having a carboxyl group and a polyfunctional isocyanate compound.

[10] A power storage device comprising:

An electric storage device for an electric storage device according to any one of items 1 to 9,

Wherein the power storage device main body portion is enclosed by the exterior material.

In the invention of [1], since at least the innermost layer of the sealant layer of the facer material contains the above-mentioned specific elastomer-modified olefin resin, the initial room strength between the facer materials can be sufficiently secured even under a high- Together, it is possible to maintain a sufficient yarn strength even if it is placed in a high-temperature environment (for example, in a summer car) for a long period of time.

In the invention of [2], the content of the olefinic thermoplastic elastomer in the innermost layer of the sealant layer is 0.1% by mass or more and less than 20% by mass, the film strength of the sealant layer increases, It is difficult to cause breakage (breakage).

In the invention of [3], since the melting point of the elastomer-modified olefin-based resin constituting the innermost layer of the sealant layer is 160 ° C to 180 ° C, the outflow of the sealant layer can be sufficiently suppressed when heat- And is also excellent in heat resistance under the high temperature environment.

In the invention of [4], the lowest crystallization temperature is 40 ° C to 80 ° C, so that the bonding time at room temperature (bonding time at the time of heat sealing) can be shortened.

In the invention of [5], since the resin (olefin resin in the innermost layer) is difficult to elute in the heat treatment, a larger adhesive strength can be secured.

In the invention of [6], since the sealant film having a tensile yield strength at 80 ° C of 3.5 MPa to 15.0 MPa is used for the sealant layer, the battery device is placed in a high temperature environment (for example, It is possible to prevent the exterior material from rupturing due to an increase in internal pressure.

In the invention of [7], since the second sealant layer on the side closest to the metal foil layer contains 50 mass% or more of the propylene-ethylene random copolymer and does not contain an elastomer component, The adhesion between the layers is improved, and even if deformation occurs, peeling between the layers is hardly caused. Further, since the second sealant layer on the side closest to the metal foil layer contains no elastomer component, a crayon (cracks / gaps) that may occur at the interface between the propylene-ethylene random copolymer and the elastomer component There is no penetration of the electrolytic solution into the vicinity of the metal foil layer by the gap between the metal foil and the metal foil layer, and sufficient insulating property can be ensured.

According to the invention of [8], the adhesion between the metal foil layer and the sealant layer can be further increased.

In the invention of [9], since the adhesive layer is composed of an adhesive containing an olefin resin having a carboxyl group and a polyfunctional isocyanate compound, the electrolyte resistance (electrolyte resistance) can be further improved.

According to the invention of [10], it is possible to sufficiently secure the initial room strength between the facings even in a high-temperature environment, and to maintain sufficient room strength even under a high temperature environment (for example, Thereby providing a battery device excellent in high-temperature durability.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing an embodiment of a casing for a power storage device according to the present invention. Fig.
2 is a cross-sectional view showing another embodiment of a casing material for a power storage device according to the present invention.
3 is a cross-sectional view showing one embodiment of a power storage device according to the present invention.
Fig. 4 is a perspective view showing the casing (planar type) constituting the power storage device of Fig. 3, the power storage device main body portion, and the external case (formed body molded in a three-dimensional shape) before being heat-sealed.

Fig. 1 shows an embodiment of a casing member 1 for a power storage device according to the present invention. The casing material 1 for the power storage device is used, for example, as a casing material for a lithium ion secondary battery. The outer casing 1 for the power storage device may be used as an outer casing material without being subjected to molding and may be used for molding such as deep drawing molding or extrusion molding and used as the outer casing 10 (See Fig. 4).

The outer casing 1 for the power storage device has a structure in which a base layer (outer layer) 2 is laminated and integrated on one surface of a metal foil layer 4 through a first adhesive layer 5, And the inner sealant layer (inner layer) 3 is laminated and integrated on the other surface of the first sealant layer 3 with the second adhesive layer 6 interposed therebetween (see FIGS. 1 and 2).

In the case 1 of Fig. 1, the inner sealant layer (inner layer) 3 is composed of a single layer (one layer) of the first sealant layer 7. Therefore, the first sealant layer 7 is disposed on the innermost side (the first sealant layer 7 is the innermost layer).

2, the inner sealant layer (inner layer) 3 includes a first sealant layer 7 which is the innermost layer and a second sealant layer 7 which is disposed closest to the metal foil layer 4 2 sealant layer 8, and the first sealant layer 7 is disposed on the innermost side.

In the present invention, the inner sealant layer (inner layer) 3 has an excellent chemical resistance against a corrosive electrolyte or the like used in a lithium ion secondary battery or the like, I am in charge. The sealant layer (inner layer) 3 is made of an unoriented sealant film.

In the present invention, the sealant layer (inner layer) 3 may be formed of one layer or a plurality of layers of two or more layers, but at least the innermost layer (inner layer) of the sealant layer (First sealant layer) 7 is configured to contain an elastomer-modified olefin resin.

The elastomer-modified olefin-based resin (polypropylene block copolymer) is preferably composed of an olefin-based thermoplastic elastomer-modified homopolypropylene and / or an olefin-based thermoplastic elastomer-modified random copolymer, and the olefin- The elastomer-modified random copolymer is an olefinic thermoplastic elastomer modified product of a random copolymer containing " propylene " and " another copolymer component other than propylene " as a copolymerization component, and the term "other copolymer component excluding propylene" Butadiene and the like, in addition to the olefin components such as ethylene, 1-butene, 1-hexene, 1-pentene and 4-methyl-1-pentene. Examples of the olefinic thermoplastic elastomer include, but are not limited to, EPR (ethylene propylene rubber), propylene-butene elastomer, propylene-butene-ethylene elastomer, EPDM (ethylene- ). Of these, EPR (ethylene propylene rubber) is preferably used.

Regarding the elastomer-modified olefin-based resin, the "olefin-based thermoplastic elastomer-modified" state may be graft polymerization or other modified state.

The elastomer-modified olefin-based resin can be produced, for example, by the following reactor-assisted method. This is merely an example, and is not particularly limited as it is produced by such a production method.

First, the homopolymer is polymerized by feeding a Ziegler-Natta catalyst, a cocatalyst, propylene and hydrogen to the first reactor. The obtained homopolypropylene is transferred to the second reactor in the state containing the unreacted propylene and the Ziegler-Natta catalyst. In the second reactor, propylene and hydrogen are added again to polymerize the homopolypropylene. The obtained homopolypropylene is transferred to the third reactor in the state containing the unreacted propylene and the Ziegler-Natta catalyst. The elastomer-modified olefin resin can be prepared by polymerizing ethylene-propylene rubber (EPR) obtained by copolymerizing ethylene and propylene by adding ethylene, propylene and hydrogen again in the third reactor. For example, the elastomer-modified olefin-based resin can be prepared by adding a solvent to the elastomer-modified olefin-based resin in a liquid phase, and conducting the reaction in a gas phase without using a solvent, Can be manufactured.

The content of the olefinic thermoplastic elastomer in the innermost layer (first sealant layer) 7 of the sealant layer 3 is preferably at least 0.1 mass% and less than 20 mass%. The homopolypropylene (the portion not modified with olefinic thermoplastic elastomer) in the innermost layer (first sealant layer) 7 of the sealant layer 3 and / or the random copolymer (olefinic thermoplastic elastomer) Is not more than 80% by mass and not more than 99% by mass.

The melting point of the elastomer-modified olefin-based resin constituting the innermost layer (first sealant layer) 7 of the sealant layer 3 is preferably in the range of 160 캜 to 180 캜. The outflow of the sealant layer 3 can be sufficiently suppressed when the casing is heat-sealed, and the heat resistance under a high-temperature environment is also excellent. Among them, the melting point of the elastomer-modified olefin resin constituting the innermost layer (first sealant layer) 7 of the sealant layer 3 is preferably 163 DEG C or higher, and the range of 163 DEG C to 169 DEG C desirable. The melting point is a melting point measured by differential scanning calorimetry (DSC) according to JIS K7121-1987.

The olefinic thermoplastic elastomer component (this component alone) present in the innermost layer (first sealant layer) 7 preferably has a plurality of crystallization temperatures. In the case of having a plurality of crystallization temperatures as described above, it is possible to obtain an effect that the resin (olefin resin in the innermost layer) is difficult to elute at the time of bonding. In the case of having a plurality of crystallization temperatures, the lowest crystallization temperature among the plurality of crystallization temperatures is preferably in the range of 40 캜 to 80 캜, more preferably in the range of 40 캜 to 75 캜 . The lowest crystallization temperature is 40 占 폚 to 80 占 폚 so that the effect of shortening the bonding time at the room temperature (bonding time at the time of heat sealing) can be obtained. The crystallization temperature is the crystallization temperature (crystallization peak) measured by differential scanning calorimetry (DSC) according to JIS K7121-1987.

The MFR of the olefinic thermoplastic elastomer component (this component alone) present in the innermost layer (first sealant layer) 7 is preferably 0.1 g / 10 min to 1.4 g / 10 min. In this case, The resin (olefin resin in the innermost layer) is difficult to elute in practice, so that a larger adhesive strength can be secured. Among them, the MFR of the olefinic thermoplastic elastomer component (this component alone) present in the innermost layer (first sealant layer) 7 is more preferably 0.1 g / 10 min to 1.0 g / 10 min or less , And particularly preferably 0.1 g / 10 min to 0.6 g / 10 min or less. The MFR (melt flow rate) is an MFR measured under the conditions of 230 占 폚 and 2.16 kg in accordance with JIS K7210-1-2014.

The sealant film constituting the sealant layer 3 preferably has a tensile yield strength at 80 캜 of from 3.5 MPa to 15.0 MPa. For example, when the sealant layer 3 is composed of only the first sealant layer 7, the first sealant film preferably has a tensile yield strength at 80 캜 of from 3.5 MPa to 15.0 MPa, When the sealant layer 3 is formed of a laminate of the first sealant layer 7 and the second sealant layer 8, the laminated sealant film has a tensile yield strength at 80 캜 of 3.5 MPa to 15.0 MPa desirable. It is assumed that the sealant layer 3 has a multilayer structure of three or more layers. When the sealant film constituting the sealant layer 3 has a tensile yield strength at 80 캜 of 3.5 MPa to 15.0 MPa as described above, even if the battery device is used for a long time in a high temperature environment (for example, in a summer vehicle) It is possible to prevent the exterior material from rupturing due to an increase in internal pressure. Above all, the sealant film constituting the sealant layer 3 is particularly preferably a film having a tensile yield strength at 80 캜 of from 4 MPa to 12 MPa.

The thickness of the innermost layer (first sealant layer) 7 is preferably at least 30 mu m, and in this case, there is an advantage that the toughness of the first sealant layer 7 can be improved. Among them, the thickness of the innermost layer (first sealant layer) 7 is more preferably 30 m to 100 m.

In the case of providing the second sealant layer 8, the thickness of the second sealant layer 8 is preferably 3 m to 60 m, more preferably 5 m to 20 m. When the second sealant layer 8 is provided, the resin forming the second sealant layer 8 is not particularly limited, and examples thereof include propylene-ethylene random copolymer, homopolypropylene , An olefin-based thermoplastic elastomer-modified homopolypropylene, an olefin-based thermoplastic elastomer-modified random copolymer ("olefin-based random copolymer containing random copolymer of propylene" and "other copolymer component other than propylene" Thermoplastic elastomer modified product).

Further, it is preferable that the thickness of the sealant layer 3 is set to 30 탆 to 200 탆.

In the present invention, the sealant layer (3) comprises a plurality of layers, an innermost layer (first sealant layer) (7) containing the elastomer-modified olefin resin, (Refer to Fig. 2), and the second sealant layer contains a propylene-ethylene random copolymer in an amount of 50 mass% or more and contains no elastomer component . In such a configuration, the second sealant layer 8 closest to the metal foil layer 4 contains 50 mass% or more of a propylene-ethylene random copolymer, and contains no elastomer component The adhesion to the metal foil layer side is improved, and even if deformation occurs, the peeling between layers becomes difficult to occur. In addition, since the second sealant layer 8 closest to the metal foil layer 4 does not contain an elastomer component, there is a possibility of occurrence at the interface between the propylene-ethylene random copolymer and the elastomer component Sufficient insulation can be ensured without the penetration of the electrolytic solution into the vicinity of the metal foil layer due to the crease (deviation at the interface without cracks or gaps). Above all, it is more preferable that the second sealant layer contains a propylene-ethylene random copolymer in an amount of 70 mass% or more and does not contain an elastomer component. Here, the composition not containing the elastomer component means that the elastomer component is not mixed (blended), and the elastomer-modified resin is not mixed.

The sealant film constituting the sealant layer (inner layer) 3 is preferably produced by a molding method such as multilayer extrusion molding, inflation molding, and T-die cast film molding.

The method for laminating the sealant film constituting the sealant layer (inner layer) 3 to the metal foil layer 4 is not particularly limited, but a dry lamination method, a sandwich lamination method (an adhesive film such as an acid denatured polypropylene, Extruding it, sand-laminating it between the metal foil and the sealant film, and then heat-laminating the film with a heat roll).

In the present invention, it is preferable that the substrate layer (outer layer) 2 is formed of a heat resistant resin layer. As the heat-resistant resin constituting the heat-resistant resin layer (2), a heat-resistant resin which does not melt at the heat room temperature at the time of heat sealing the exterior material is used. As the heat resistant resin, it is preferable to use a heat resistant resin having a melting point higher than the melting point of the sealant layer (3) by at least 10 DEG C, and to use a heat resistant resin having a melting point higher than the melting point of the sealant layer (3) Particularly preferred.

The heat resistant resin layer (outer layer) 2 is not particularly limited, and for example, a polyamide film such as a nylon film, a polyester film, and the like are preferably used. As the heat resistant resin layer 2, a biaxially oriented polyamide film such as a biaxially oriented nylon film, a biaxially oriented polybutylene terephthalate (PBT) film, a biaxially oriented polyethylene terephthalate (PET) film, or a biaxially oriented poly It is particularly preferred to use a biaxially oriented polyethylene naphthalate (PEN) film. The nylon film is not particularly limited, and examples thereof include 6 nylon film, 6,6 nylon film, and MXD nylon film. The heat resistant resin layer 2 may be formed of a single layer or may be formed of a multilayer (eg, PET film / nylon film multilayer) formed of a polyester film / polyamide film. Further, in the case of the above-mentioned multilayer structure, it is preferable to arrange the polyester film side on the outermost side.

The thickness of the outer layer (base layer) 2 is preferably 2 m to 50 m. When a polyester film is used, the thickness is preferably 5 占 퐉 to 40 占 퐉, and when a nylon film is used, the thickness is preferably 15 占 퐉 to 50 占 퐉. It is possible to secure a sufficient strength as an exterior material by setting it to a value not less than the above-mentioned extremely low limit value and to set the value to be not more than the above extremely high limit value so as to reduce the stress during molding such as extrusion molding and drawing, have.

In the casing for a power storage device according to the present invention, the metal foil layer (4) plays a role of imparting gas barrier properties to prevent the penetration of oxygen and moisture into the casing (1). The metal foil layer 4 is not particularly limited. Examples of the metal foil layer 4 include aluminum foil, SUS foil (stainless steel foil) and copper foil. Among them, aluminum foil and SUS foil (stainless foil) . The thickness of the metal foil layer 4 is preferably 10 to 120 mu m. It is possible to prevent the occurrence of pinholes at the time of rolling at the time of manufacturing the metal foil and to reduce the stress at the time of forming such as extrusion molding and drawing by making it 120 탆 or less, have.

It is preferable that the metal foil layer 4 is chemically treated at least on the inner side (the side of the second adhesive layer 6). By such a chemical conversion treatment, corrosion of the surface of the metal foil by the contents (electrolytic solution of the battery, etc.) can be sufficiently prevented. For example, the metal foil is subjected to a chemical conversion treatment by the following process. That is, for example, on the surface of the metal foil subjected to the degreasing treatment,

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

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

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

A chemical conversion treatment is carried out by applying (coating) any one of the aqueous solutions 1) to 3), and then drying.

The above-mentioned chemical conversion film is preferably from 0.1 mg / m 2 to 50 mg / m 2, particularly preferably from 2 mg / m 2 to 20 mg / m 2 as the chromium adhering amount (per one side).

The first adhesive layer (outer adhesive layer) 5 is not particularly limited, and examples thereof include a polyurethane polyolefin adhesive layer, a polyurethane adhesive layer, a polyester polyurethane adhesive layer, a polyether polyurethane adhesive layer and the like . The thickness of the first adhesive layer 5 is preferably set to 1 탆 to 6 탆. Particularly, from the viewpoint of thinning and lightening of the facer material 1, it is particularly preferable that the thickness of the first adhesive layer 5 is set to 1 mu m to 3 mu m.

The second adhesive layer (inner adhesive layer) 6 is not particularly limited, and for example, those exemplified as the first adhesive layer 5 may be used, but a polyolefin-based adhesive Is preferably used. Among them, it is particularly preferable that the second adhesive layer (inner adhesive layer) 6 is formed of an adhesive containing an olefin resin having a carboxyl group and a polyfunctional isocyanate compound. The second adhesive layer can be formed by dry lamination of the adhesive. Alternatively, it is particularly preferable that the second adhesive layer (inner adhesive layer) 6 is formed of an olefin resin having a carboxyl group. In this case, the second adhesive layer can be formed by extrusion lamination by melt extrusion of an olefin resin having a carboxyl group. Examples of the olefin resin having a carboxyl group include, but are not limited to, maleic acid-modified polypropylene, maleic acid-modified polyethylene, acrylic acid-modified polypropylene, acrylic acid-modified polyethylene, methacrylic acid- modified polypropylene, And carboxylic acid-modified olefin resins such as fumaric acid-modified polypropylene and fumaric acid-modified polyethylene. The thickness of the second adhesive layer 6 is preferably set to 1 탆 to 4 탆. Particularly, from the viewpoint of thinning and lightening of the exterior material, it is particularly preferable that the thickness of the second adhesive layer 6 is set to 1 탆 to 3 탆.

An external case (battery case or the like) 10 can be obtained by molding (by deep drawing molding, extrusion molding, etc.) of the exterior member 1 of the present invention (FIG. In addition, the outer sheath 1 of the present invention can be used as it is without being provided for molding (Fig. 4).

An embodiment of the electric storage device 30 constructed using the exterior member 1 of the present invention is shown in Fig. This electric storage device 30 is a lithium ion secondary battery. In this embodiment, as shown in Figs. 3 and 4, the outer case 10 is formed by molding the outer case 1, and the outer case 15 is formed by the outer case 1 in a planar form. An electric storage device main body (electrochemical device or the like) 31 having an approximately rectangular parallelepiped shape is accommodated in the housing recessed portion of the outer case 10 obtained by molding the exterior material 1 of the present invention, The exterior material 1 of the present invention is disposed on the sealant layer 31 in such a manner that the sealant layer 3 side is located on the inner side (lower side) of the sealant layer 1 3 and the sealant layer 3 of the flange portion (sealing periphery portion) 29 of the outer case 10 are sealed and sealed by the heat seal so that the electrical storage device 30 of the present invention (See Figs. 3 and 4). The inner surface of the receiving recess of the outer case 10 is a sealant layer 3 and the outer surface of the receiving recess is a base layer (outer layer) 2 (see FIG. 4).

3, reference numeral 39 denotes a heat seal portion (portion) in which the periphery of the casing member 1 and the flange portion (sealing periphery portion) 29 of the casing member 10 are joined (welded). In the electrical storage device 30, the tip end of the tab lead connected to the power storage device main body portion 31 is led out of the exterior member 15, but illustration thereof is omitted.

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

The width of the heat seal portion 39 is preferably set to 0.5 mm or more. By setting it to 0.5 mm or more, sealing can be reliably performed. In particular, the width of the heat seal portion 39 is preferably set to 3 mm to 15 mm.

In the above-described embodiment, the case member 15 is composed of the case member 10 obtained by molding the case member 1 and the case member 1 in a planar shape (see FIGS. 3 and 4) The present invention is not limited to the combination. For example, the exterior member 15 may be constituted by a pair of planar exterior materials 1, or may be constituted by a pair of exterior cases 10.

Example

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

<Materials Used>

(Elastomer-modified olefin resin (A))

The elastomer-modified olefin-based resin (A) is composed of EPR-modified homopolypropylene and an ethylene-propylene random copolymer. The EPR means an ethylene-propylene rubber. The content of the elastomer component in the elastomer-modified olefin resin (A) is 15% by mass. The melting point of the elastomer-modified olefin-based resin (A) is 166 ° C.

(Elastomer-modified olefin-based resin (B))

The elastomer-modified olefin-based resin (B) is composed of a propylene-butene elastomer-modified homopolypropylene and an ethylene-propylene random copolymer-modified propylene-butene elastomer. The content of the elastomer component in the elastomer-modified olefin-based resin (B) is 18% by mass. The melting point of the elastomer-modified olefin-based resin (B) is 164 占 폚.

(Elastomer-modified olefin-based resin (C))

The elastomer-modified olefin-based resin (C) is composed of propylene-butene-ethylene elastomer-modified homopolypropylene and a propylene-butene-ethylene elastomer modified product of an ethylene-propylene random copolymer. The content of the elastomer component in the elastomer-modified olefin-based resin (C) is 16% by mass. The melting point of the elastomer-modified olefin-based resin (C) is 164 占 폚.

<Example 1>

A chemical conversion treatment liquid composed of phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water (water) and alcohol was applied to both surfaces of an aluminum foil 4 having a thickness of 35 탆 and then dried at 180 캜 To form a chemical conversion film. The deposition amount of chromium in this chemical conversion coating was 10 mg / m 2 per one side.

Next, a biaxially stretched 6 nylon film (2) having a thickness of 15 탆 was dry-laminated on one surface of the chemically treated aluminum foil (4) through a two-liquid curing type urethane adhesive (outer adhesive) (Right).

Next, after a sealant film (first sealant layer) 7 of 80 占 퐉 in thickness made of the elastomer-modified olefin resin (A) was extruded, two sheets of sealant film 7 (3) The other surface of the aluminum foil 4 after the dry lamination was overlaid through a liquid-curing urethane-based adhesive (inner adhesive layer) 6, sandwiched between a rubber nip roll and a laminate roll heated to 100 캜 And then subjected to dry lamination by squeezing. Thereafter, the laminate was aged at 50 ° C for 5 days (heated) to obtain a jacket 1 for an electric storage device having the structure shown in Fig.

<Practical Example 2>

1 was used in place of the two-liquid curing type acrylic adhesive 6 in place of the two-liquid curing type urethane adhesive as the inner adhesive 6, 1).

&Lt; Example 3 >

A chemical conversion treatment liquid composed of phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water and alcohol was applied to both surfaces of an aluminum foil 4 having a thickness of 35 탆 and then dried at 180 캜, To form a film. The deposition amount of chromium in this chemical conversion coating was 10 mg / m 2 per one side.

Next, a biaxially stretched 6 nylon film 2 having a thickness of 15 탆 was dry-laminated (laminated) on one surface of the chemically treated aluminum foil 4 through a two-liquid curing type urethane adhesive 5, .

Next, on the other surface of the aluminum foil 4 after the dry lamination, a maleic anhydride-modified polypropylene film (inner adhesive layer) 6 having a thickness of 4 m and a propylene-ethylene random copolymer film (2 sealant layer) 8 and an elastomer-modified olefin resin (A) film (first sealant layer) 7 having a thickness of 72 탆 were coextruded in this order to form a rubber nip roll And heated at 100 deg. C to dry laminate the laminate. After that, the laminate was subjected to aging at 50 DEG C for 5 days (heating) (1).

<Example 4>

A chemical conversion treatment liquid composed of phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water and alcohol was applied to both surfaces of an aluminum foil 4 having a thickness of 35 탆 and then dried at 180 캜, To form a film. The deposition amount of chromium in this chemical conversion coating was 10 mg / m 2 per one side.

Next, a biaxially stretched 6 nylon film 2 having a thickness of 15 탆 was dry-laminated (laminated) on one surface of the chemically treated aluminum foil 4 through a two-liquid curing type urethane adhesive 5, .

Next, on the other surface of the aluminum foil 4 after the dry lamination, a maleic anhydride-modified polypropylene film (inner adhesive layer) 6 having a thickness of 4 占 퐉 and an elastomer-modified olefinic resin (A ) Film 3 were co-extruded in this order, sandwiched between a rubber nip roll and a laminate roll heated to 100 占 폚, and then subjected to dry lamination by compression bonding. Thereafter, the laminate was aged at 50 占 폚 for 5 days (Heated) to obtain a jacket 1 for a power storage device having the structure shown in Fig.

&Lt; Example 5 >

1 was used in place of the elastomer-modified olefin-based resin (B) in place of the elastomer-modified olefin-based resin (A) .

&Lt; Example 6 >

1 was used in place of the elastomer-modified olefin resin (C) in place of the elastomer-modified olefin resin (A) .

&Lt; Example 7 >

A chemical conversion treatment liquid composed of phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water and alcohol was applied to both surfaces of an aluminum foil 4 having a thickness of 35 탆 and then dried at 180 캜, To form a film. The deposition amount of chromium in this chemical conversion coating was 10 mg / m 2 per one side.

Next, a biaxially stretched 6 nylon film 2 having a thickness of 15 탆 was dry-laminated (laminated) on one surface of the chemically treated aluminum foil 4 through a two-liquid curing type urethane adhesive 5, .

Next, a two-liquid curing type urethane adhesive (inner adhesive layer) 6 was applied to the other surface of the aluminum foil 4 after the dry lamination, and then a homopolypropylene film 2 sealant layer) 8 and an elastomer-modified olefin resin (A) film (first sealant layer) 7 having a thickness of 72 탆 were co-extruded in this order, And then the laminate was subjected to dry lamination by compression bonding. After that, the laminate was subjected to aging (heating) at 50 DEG C for 5 days to obtain an outer casing 1 for a power storage device having the structure shown in Fig. 2 .

&Lt; Example 8 >

As in the case of Example 7 except that a 8 μm-thick propylene-ethylene random copolymer film (8) was used in place of the 8 μm-thick homopolypropylene film as the second sealant layer (8) Thereby obtaining the casing member 1 for the power storage device shown in the figure.

&Lt; Example 9 &

2 was used in place of the two-liquid curing type urethane adhesive in place of the two-liquid curing type urethane adhesive as the inner adhesive 6, 1).

<Comparative Example 1>

A casing for a power storage device having the structure shown in Fig. 1 was obtained in the same manner as in Example 1 except that a propylene-ethylene random copolymer was used in place of the elastomer-modified olefin-based resin (A).

<Comparative Example 2>

A chemical conversion treatment liquid composed of phosphoric acid, polyacrylic acid (acrylic resin), chromium (III) salt compound, water and alcohol was applied to both surfaces of an aluminum foil 4 having a thickness of 35 탆 and then dried at 180 캜, To form a film. The deposition amount of chromium in this chemical conversion coating was 10 mg / m 2 per one side.

Next, a biaxially stretched 6 nylon film 2 having a thickness of 15 탆 was dry-laminated (laminated) on one surface of the chemically treated aluminum foil 4 through a two-liquid curing type urethane adhesive 5, .

Next, a two-liquid curing type acrylic adhesive 6 was applied to the other surface of the aluminum foil 4 after the dry lamination, and then an elastomer-modified olefin resin (A) film (Second sealant layer) 8 and a 12 占 퐉 -thick propylene-ethylene random copolymer film (first sealant layer) 7 were co-extruded in this order, and the rubber nip rolls were heated to 100 占 폚 And then subjected to dry lamination by squeezing. Then, the laminate was aged at 50 캜 for 5 days (heated) to obtain a casing for a power storage device having the structure shown in Fig. 2.

The tensile yield strength (see Table 1) of the sealant film (thickness 80 탆) (3) used to prepare the exterior materials of Examples 1 to 9 and Comparative Examples 1 and 2 was determined by measuring the tensile yield strength Tensile yield strength).

<Measurement method of tensile yield strength of sealant film>

A test piece of type 2 (having a length of 150 mm or more) was prepared in accordance with JIS K7127-1999 (tensile test method of plastic film) with respect to the non-oriented sealant film 3 (thickness 80 탆) Tensile yield strength (tensile yield strength) was measured under the conditions of a sample width of 15 mm, a distance between grippers of 100 mm, a distance between marks and a distance of 50 mm, and a tensile rate of 100 mm / Respectively. The load at the yield point in the S-S curve is called the tensile yield strength. Further, the test specimens were set in a tensile tester in a thermostatic chamber set at 80 DEG C, and the specimens were allowed to stand at 80 DEG C for 1 minute and then subjected to a tensile test under an environment of 80 DEG C. The results of measurement of the tensile yield strength at 80 DEG C are shown in Table 1.

For example, when the sealant film 3 having a thickness of 64 占 퐉 is used as the second sealant layer having a thickness of 6 占 퐉 and the second sealant layer having a thickness of 58 占 퐉, In the case of the layered structure, a test piece having a thickness of 80 占 퐉 is prepared and measured so that the thickness ratio of the two layers does not change. That is, a test piece having a two-layer laminated structure of a second sealant layer having a thickness of 7.5 mu m and a first sealant layer having a thickness of 72.5 mu m is prepared and measured. In the case of a laminated structure having three or more layers, a test piece having a thickness of 80 占 퐉 is similarly prepared and measured.

The outer sheath for each of the power storage devices obtained as described above was evaluated based on the following measuring methods.

&Lt; Measurement method of initial room strength at high temperature >

Two test specimens having a width of 15 mm and a length of 150 mm were cut out from the obtained outer sheath and then placed in contact with each other so that the inner sealant layers of the two test specimens were in contact with each other. Heat-sealing was performed by one-side heating using the apparatus TP-701-A under conditions of a heat room temperature of 200 占 폚, a pressure of 0.2 MPa (gauge display pressure), and a real time of 2 seconds.

Next, a pair of outer sheaths in which the inner sealant layers were heat-sealed to each other as described above was stuck to a stretch test apparatus (AGS-5kNX) manufactured by Shimadzu Corporation in a thermostatic chamber according to JIS Z0238-1998, (Test specimen) was peeled off 90 degrees between the inner sealant layers of the seal portion at a tensile speed of 100 mm / min, and the peel strength was measured as the actual strength (N / 15 mm width). The actual strength at 100 占 폚 and the actual strength at 120 占 폚 were measured.

In the measurement of the room strength at 100 占 폚, the specimen was set in a tensile tester in a thermostatic chamber set at 100 占 폚, and the specimen was allowed to stand for one minute under the environment of 100 占 폚, and then the measurement was carried out at 100 占 폚. Measurement of the actual strength at 120 占 폚 was also carried out by setting the test specimen in a tensile tester in a thermostatic chamber set at 120 占 폚 and then standing at 120 占 폚 for 1 minute and then under 120 占 폚.

Both the yarn strength at 100 ° C and the yarn strength at 120 ° C are referred to as passing at 27N / 15mm width or more.

&Lt; Measurement of yarn strength after 90 days in a high-temperature environment &

Two outer sheaths cut into a size of 200 mm length x 150 mm width were placed so as to face each other with the sealant layers facing inwardly and the edges of the three sides were heat-sealed at 180 DEG C and 0.2 MPa for 2 seconds. 10 ml of the electrolytic solution was injected from the openings of the other side which had not been broken, and the remaining one side was heat-sealed while removing air from the remaining one side under the same conditions as above to prepare a simulated battery (test body). As the electrolyte, an electrolytic solution prepared by dissolving lithium hexafluorophosphate (LiPF ₆ ) at a concentration of 1 mol / l in a mixed solvent in which ethylene carbonate (EC) and dimethyl carbonate (DMC) were mixed at an equivalent volume ratio was used.

The obtained simulated battery was placed in a constant temperature and humidity chamber made by ESPEC and allowed to stand for 90 days under the condition of 80 占 폚 and 90% Rh (exposed in a high temperature and high humidity environment for 90 days).

After the elapse of 90 days, the simulated battery was taken out, one side was opened to remove the electrolyte, the inside was washed several times with water, and then the two outer casings were overlapped so as to include the seal portions of the two outer casings, (AGS-5kNX) manufactured by Shimadzu Corporation (AGS-5kNX) in accordance with JIS Z0238-1998 with a pair of outer sheaths obtained by cutting into a size of 150 mm in length, Were peeled from each other at 90 degrees at a tensile speed of 100 mm / min. The peel strength was measured as the actual strength (N / 15 mm width). Further, the room strength at 25 캜 was measured. A yarn strength of 27N / 15㎜ width or more is called "pass".

As apparent from Table 1, the casing materials for Examples 1 to 9 according to the present invention can sufficiently secure the initial room strength even under a high temperature environment, and can maintain sufficient room strength even when placed in a high temperature environment for a long period of time .

On the other hand, in Comparative Examples 1 and 2, the initial yarn strength was insufficient under a high-temperature environment, and the yarn strength after being placed for a long period under a high-temperature environment was considerably reduced.

[Industrial Availability]

As a concrete example, the exterior material for a power storage device manufactured using the sealant film according to the present invention and the exterior material for a power storage device according to the present invention are, for example,

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

· Lithium ion capacitor

· Electric double layer condenser

And the like. Further, the electrical storage device according to the present invention includes all the solid-state batteries in addition to the above-described electrical storage device.

This application is a continuation of Japanese Patent Application No. 2016-159935, filed on August 17, 2016, which is incorporated herein by reference in its entirety.

The terms and explanations used here are used for explaining the embodiments of the present invention, and the present invention is not limited thereto. It is intended that the present invention not be limited by any of the details of the description provided herein except as defined in the appended claims.

1: Outer material for power storage device
2: Heat resistant resin layer (outer layer)
3: sealant layer (inner layer)
4: metal foil layer
5: outer adhesive layer (first adhesive layer)
6: Inner adhesive layer (second adhesive layer)
7: first sealant layer (innermost layer; innermost sealant layer)
8: second sealant layer (sealant layer closest to the metal foil layer side)
10: External case for power storage device
15: outer member
30: Power storage device
31: Power storage device main body part

Claims (10)

A heat-resistant resin layer as an outer layer, a sealant layer as an inner layer, and a metal foil layer disposed between the both layers,
Wherein the sealant layer comprises one or more layers, at least an innermost layer of the sealant layer contains an elastomer-modified olefin resin,
The elastomer-modified olefin-based resin is composed of an olefin-based thermoplastic elastomer-modified homopolypropylene and / or an olefin-based thermoplastic elastomer-modified random copolymer,
Wherein the olefinic thermoplastic elastomeric modified random copolymer is an olefinic thermoplastic elastomeric modification of a random copolymer containing a copolymerizable component other than propylene and propylene as a copolymerization component. The method according to claim 1,
Wherein the content of the olefinic thermoplastic elastomer in the innermost layer is 0.1% by mass or more and less than 20% by mass. 3. The method according to claim 1 or 2,
Wherein the melting point of the elastomer-modified olefin-based resin constituting the innermost layer is 160 占 폚 to 180 占 폚. 3. The method according to claim 1 or 2,
Wherein the olefinic thermoplastic elastomer component present in the innermost layer has a plurality of crystallization temperatures and the lowest crystallization temperature among the plurality of crystallization temperatures is 40 占 폚 to 80 占 폚. 3. The method according to claim 1 or 2,
Wherein the MFR of the olefinic thermoplastic elastomer component present in the innermost layer is 0.1 g / 10 min to 1.4 g / 10 min. 3. The method according to claim 1 or 2,
Wherein the sealant film constituting the sealant layer has a tensile yield strength at 80 캜 of 3.5 MPa to 15.0 MPa. 3. The method according to claim 1 or 2,
Wherein the sealant layer is composed of a plurality of layers, a second sealant layer is disposed on a side closest to the metal foil layer in the sealant layer, and the second sealant layer contains 50% by mass or more of a propylene-ethylene random copolymer , And does not contain an elastomer component. 3. The method according to claim 1 or 2,
Wherein the metal foil layer and the sealant layer are bonded to each other through an adhesive layer. 9. The method of claim 8,
Characterized in that the adhesive layer comprises an adhesive containing an olefin resin having a carboxyl group and a polyfunctional isocyanate compound. A power storage device main body part,
An electric storage device for an electric storage device according to any one of claims 1 to 9,
Wherein the power storage device main body portion is enclosed by the exterior material.

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